Leucine reduces reactive oxygen species levels via an energy metabolism switch by activation of the mTOR-HIF-1α pathway in porcine intestinal epithelial cells.

PubMed

Hu, Jun; Nie, Yangfan; Chen, Shifeng; Xie, Chunlin; Fan, Qiwen; Wang, Zhichang; Long, Baisheng; Yan, Guokai; Zhong, Qing; Yan, Xianghua

2017-08-01

Leucine serves not only as a substrate for protein synthesis, but also as a signal molecule involved in protein metabolism. However, whether the levels of cellular reactive oxygen species (ROS), which have damaging effects on cellular DNA, proteins, and lipids, are regulated by leucine is still unclear. Here, we report that leucine supplementation reduces ROS levels in intestinal epithelial cells of weaned piglets. A proteomics analysis revealed that leucine supplementation induces an energy metabolism switch from oxidative phosphorylation (OXPHOS) towards glycolysis. The leucine-induced ROS reduction and the energy metabolism switch were further validated in cultured cells. Mechanistically, our data revealed that leucine-induced ROS reduction actually depends on the energy metabolism switch from OXPHOS towards glycolysis through the mechanistic target of rapamycin (mTOR)- hypoxia-inducible factor-1alpha (HIF-1α) pathway. These findings reveal a vital regulatory role of leucine as the signal molecule involved in an energy metabolism switch in mammals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inflammatory signaling pathways induced by Helicobacter pylori in primary human gastric epithelial cells.

PubMed

Tran, Cong Tri; Garcia, Magali; Garnier, Martine; Burucoa, Christophe; Bodet, Charles

2017-02-01

Inflammatory signaling pathways induced by Helicobacter pylori remain unclear, having been studied mostly on cell-line models derived from gastric adenocarcinoma with potentially altered signaling pathways and nonfunctional receptors. Here, H. pylori-induced signaling pathways were investigated in primary human gastric epithelial cells. Inflammatory response was analyzed on chemokine mRNA expression and production after infection of gastric epithelial cells by H. pylori strains, B128 and B128Δ cagM, a cag type IV secretion system defective strain. Signaling pathway involvement was investigated using inhibitors of epidermal growth factor receptor (EGFR), MAPK, JAK and blocking Abs against TLR2 and TLR4. Inhibitors of EGFR, MAPK and JAK significantly reduced the chemokine mRNA expression and production induced by both H. pylori strains at 3 h and 24 h post-infection. JNK inhibitor reduced chemokine production at 24 h post-infection. Blocking Abs against TLR2 but not TLR4 showed significant reduction of chemokine secretion. Using primary culture of human gastric epithelial cells, our data suggest that H. pylori can be recognized by TLR2, leading to chemokine induction, and that EGFR, MAPK and the JAK/STAT signaling pathways play a key role in the H. pylori-induced CXCL1, CXCL5 and CXCL8 response in a cag pathogenicity island-independent manner.

Doxorubicin-induced mitophagy and mitochondrial damage is associated with dysregulation of the PINK1/parkin pathway.

PubMed

Yin, Jian; Guo, Jiabin; Zhang, Qiang; Cui, Lan; Zhang, Li; Zhang, Tingfen; Zhao, Jun; Li, Jin; Middleton, Alistair; Carmichael, Paul L; Peng, Shuangqing

2018-09-01

The usefulness of doxorubicin (DOX), a potent anticancer agent, is limited by its cardiotoxicity. Mitochondria play a central role in DOX-induced cardiotoxicity though the precise mechanisms are still obscure. Increasing evidence indicates that excessive activation of mitophagy and mitochondrial dysfunction are key causal events leading to DOX-induced cardiac injury. The PINK1/parkin pathway has emerged as a critical pathway in regulation of mitophagy as well as mitochondrial function. The present study was aimed to investigate the role of PINK1/parkin pathway in DOX-induced mitochondrial damage and cardiotoxicity. Our results showed that DOX concentration-dependently induced cytotoxicity and mitochondrial toxic effects including mitochondrial superoxide accumulation, decreased mitochondrial membrane potential and mitochondrial DNA copy number, as well as mitochondrial ultrastructural alterations. DOX induced mitophagy as evidenced by increases of the markers of autophagosomes, LC3, Beclin 1, reduction of p62, and co-localization of LC3 in mitochondria. DOX activated PINK1/parkin pathway and promoted translocation of PINK1/parkin to mitochondria. Meanwhile, DOX inhibited the expression of PGC-1α and its downstream targets nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), and reduced the expression of mitochondrial proteins. Inhibition of mitophagy by mdivi-1 was found to attenuate activation of the PINK1/parkin pathway by DOX and preserve mitochondrial biogenesis, consequently mitigating DOX-induced mitochondrial superoxide overproduction and mitochondrial dysfunction. Moreover, scavenging mitochondrial superoxide by Mito-tempo was also found to effectively attenuate activation of the PINK1/parkin pathway and rescue the cells from DOX-induced adverse effects. Taken together, these findings suggest that DOX-induced mitophagy and mitochondrial damage in cardiomyocytes are mediated, at least in part, by dysregulation of the PINK1/parkin pathway. Copyright © 2018 Elsevier Ltd. All rights reserved.

Lycium barbarum Polysaccharides Protect against Trimethyltin Chloride-Induced Apoptosis via Sonic Hedgehog and PI3K/Akt Signaling Pathways in Mouse Neuro-2a Cells.

PubMed

Zhao, Wanyun; Pan, Xiaoqi; Li, Tao; Zhang, Changchun; Shi, Nian

2016-01-01

Trimethyltin chloride (TMT) is a classic neurotoxicant that can cause severe neurodegenerative diseases. Some signaling pathways involving cell death play pivotal roles in the central nervous system. In this study, the role of Sonic Hedgehog (Shh) and PI3K/Akt pathways in TMT-induced apoptosis and protective effect of Lycium barbarum polysaccharides (LBP) on mouse neuro-2a (N2a) cells were investigated. Results showed that TMT treatment significantly enhanced apoptosis, upregulated proapoptotic Bax, downregulated antiapoptotic Bcl-2 expression, and increased caspase-3 activity in a dose-dependent manner in N2a cells. TMT induced oxidative stress in cells, performing reactive oxygen species (ROS) and malondialdehyde (MDA) excessive generation, and superoxide dismutase (SOD) activity reduction. TMT significantly decreased phosphorylated glycogen synthase kinase-3β (GSK-3β) and inhibited Shh and PI3K/Akt pathways. However, the addition of LBP upregulated GSK-3β phosphorylation, activated Shh and PI3K/Akt pathways, and eventually reduced apoptosis and oxidative stress caused by TMT. The interaction between Shh and PI3K/Akt pathways was clarified by specific PI3K inhibitor LY294002 or Shh inhibitor GDC-0449. Moreover, LY294002 and GDC-0449 pretreatment both induced phosphorylated GSK-3β downregulation and significantly promoted apoptosis induced by TMT. These results suggest that LBP could reduce TMT-induced N2a cells apoptosis by regulating GSK-3β phosphorylation, Shh, and PI3K/Akt signaling pathways.

Lycium barbarum Polysaccharides Protect against Trimethyltin Chloride-Induced Apoptosis via Sonic Hedgehog and PI3K/Akt Signaling Pathways in Mouse Neuro-2a Cells

PubMed Central

Zhao, Wanyun; Pan, Xiaoqi; Li, Tao; Zhang, Changchun; Shi, Nian

2016-01-01

Trimethyltin chloride (TMT) is a classic neurotoxicant that can cause severe neurodegenerative diseases. Some signaling pathways involving cell death play pivotal roles in the central nervous system. In this study, the role of Sonic Hedgehog (Shh) and PI3K/Akt pathways in TMT-induced apoptosis and protective effect of Lycium barbarum polysaccharides (LBP) on mouse neuro-2a (N2a) cells were investigated. Results showed that TMT treatment significantly enhanced apoptosis, upregulated proapoptotic Bax, downregulated antiapoptotic Bcl-2 expression, and increased caspase-3 activity in a dose-dependent manner in N2a cells. TMT induced oxidative stress in cells, performing reactive oxygen species (ROS) and malondialdehyde (MDA) excessive generation, and superoxide dismutase (SOD) activity reduction. TMT significantly decreased phosphorylated glycogen synthase kinase-3β (GSK-3β) and inhibited Shh and PI3K/Akt pathways. However, the addition of LBP upregulated GSK-3β phosphorylation, activated Shh and PI3K/Akt pathways, and eventually reduced apoptosis and oxidative stress caused by TMT. The interaction between Shh and PI3K/Akt pathways was clarified by specific PI3K inhibitor LY294002 or Shh inhibitor GDC-0449. Moreover, LY294002 and GDC-0449 pretreatment both induced phosphorylated GSK-3β downregulation and significantly promoted apoptosis induced by TMT. These results suggest that LBP could reduce TMT-induced N2a cells apoptosis by regulating GSK-3β phosphorylation, Shh, and PI3K/Akt signaling pathways. PMID:27143997

Berberine regulates AMP-activated protein kinase signaling pathways and inhibits colon tumorigenesis in mice

PubMed Central

Li, Weidong; Hua, Baojin; Saud, Shakir M.; Lin, Hongsheng; Hou, Wei; Matter, Matthias S.; Jia, Libin; Colburn, Nancy H.; Young, Matthew R.

2015-01-01

Colorectal cancer, a leading cause of cancer death, has been linked to inflammation and obesity. Berberine, an isoquinoline alkaloid, possesses anti-inflammatory, anti-diabetes and anti-tumor properties. In the azoxymethane initiated and dextran sulfate sodium (AOM/DSS) promoted colorectal carcinogenesis mouse model, berberine treated mice showed a 60% reduction in tumor number (P=0.009), a 48% reduction in tumors <2 mm, (P=0.05); 94% reduction in tumors 2-4 mm, (P=0.001) and 100% reduction in tumors >4 mm (P=0.02) compared to vehicle treated mice. Berberine also decreased AOM/DSS induced Ki-67 and COX-2 expression. In vitro analysis showed that in addition to its anti-proliferation activity, berberine also induced apoptosis in colorectal cancer cell lines. Berberine activated AMP-activated protein kinase (AMPK), a major regulator of metabolic pathways, and inhibited mammalian target of rapamycin (mTOR), a downstream target of AMPK. Furthermore, 4E-binding protein-1 and p70 ribosomal S6 kinases, downstream targets of mTOR, were down regulated by berberine treatment. Berberine did not affect Liver kinase B1 (LKB1) activity or the mitogen-activated protein kinase pathway. Berberine inhibited Nuclear Factor kappa-B (NF-κB) activity, reduced the expression of cyclin D1 and survivin, induced phosphorylation of p53 and increased caspase-3 cleavage in vitro. Berberine inhibition of mTOR activity and p53 phosphorylation was found to be AMPK dependent, while inhibition NF-κB was AMPK independent. In vivo, berberine also activated AMPK, inhibited mTOR and p65 phosphorylation and activated caspase-3 cleavage. Our data suggests that berberine suppresses colon epithelial proliferation and tumorigenesis via AMPK dependent inhibition of mTOR activity and AMPK independent inhibition of NF-κB. PMID:24838344

Naringin rescued the TNF-α-induced inhibition of osteogenesis of bone marrow-derived mesenchymal stem cells by depressing the activation of NF-кB signaling pathway.

PubMed

Cao, Xvhai; Lin, Weilong; Liang, Chengwei; Zhang, Dong; Yang, Fengjian; Zhang, Yan; Zhang, Xuelin; Feng, Jianyong; Chen, Cong

2015-07-01

Naringin exhibits antiinflammatory activity and is shown to induce bone formation. Yet the impact of naringin on inflammation-affected bone marrow-derived mesenchymal stem cell (BM-MSC), a promising tool for the regenerative treatment of bone injury, remained to be investigated. We first cultured and characterized the BM-MSCs in vitro and observe the effects of treatments of TNF-α, naringin, or the combination of both on osteogenic differentiation. TNF-α administered at the concentration of 20 ng/ml results in significant reductions in MSC's cell survival, alkaline phosphatase activity and expressions of two osteogenic genes, Runx2 and Osx. Simultaneous treatment of both TNF-α and naringin is able to rescue such reductions. Further mechanistic studies indicate that TNF-α treatment activates the NF-кB signaling pathway, evidenced by elevated p-IкBα level as well as the increased nuclear fraction of NF-кB subunit, p65. Finally, treatment with both TNF-α and naringin decreases expressions of p-IкBα and nuclear p65, and thus represses NF-кB pathway activated by sole TNF-α treatment. Our findings provide a molecular basis by which naringin restores the TNF-α-induced damage in MSCs and provide novel insights into the application of naringin in the MSC-based treatments for inflammation-induced bone injury.

Enzymatic reduction of disulfide bonds in lysosomes: Characterization of a Gamma-interferon-inducible lysosomal thiol reductase (GILT)

NASA Astrophysics Data System (ADS)

Arunachalam, Balasubramanian; Phan, Uyen T.; Geuze, Hans J.; Cresswell, Peter

2000-01-01

Proteins internalized into the endocytic pathway are usually degraded. Efficient proteolysis requires denaturation, induced by acidic conditions within lysosomes, and reduction of inter- and intrachain disulfide bonds. Cytosolic reduction is mediated enzymatically by thioredoxin, but the mechanism of lysosomal reduction is unknown. We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro. The active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids, similar to other enzymes of the thioredoxin family. The enzyme is a soluble glycoprotein that is synthesized as a precursor. After delivery into the endosomal/lysosomal system by the mannose 6-phosphate receptor, N- and C-terminal prosequences are removed. The enzyme is expressed constitutively in antigen-presenting cells and induced by IFN-γ in other cell types, suggesting a potentially important role in antigen processing.

Halobenzoquinone-Induced Alteration of Gene Expression Associated with Oxidative Stress Signaling Pathways.

PubMed

Li, Jinhua; Moe, Birget; Liu, Yanming; Li, Xing-Fang

2018-06-05

Halobenzoquinones (HBQs) are emerging disinfection byproducts (DBPs) that effectively induce reactive oxygen species and oxidative damage in vitro. However, the impacts of HBQs on oxidative-stress-related gene expression have not been investigated. In this study, we examined alterations in the expression of 44 genes related to oxidative-stress-induced signaling pathways in human uroepithelial cells (SV-HUC-1) upon exposure to six HBQs. The results show the structure-dependent effects of HBQs on the studied gene expression. After 2 h of exposure, the expression levels of 9 to 28 genes were altered, while after 8 h of exposure, the expression levels of 29 to 31 genes were altered. Four genes ( HMOX1, NQO1, PTGS2, and TXNRD1) were significantly upregulated by all six HBQs at both exposure time points. Ingenuity pathway analysis revealed that the Nrf2 pathway was significantly responsive to HBQ exposure. Other canonical pathways responsive to HBQ exposure included GSH redox reductions, superoxide radical degradation, and xenobiotic metabolism signaling. This study has demonstrated that HBQs significantly alter the gene expression of oxidative-stress-related signaling pathways and contributes to the understanding of HBQ-DBP-associated toxicity.

Intrinsic Apoptosis Pathway in Fallopian Tube Epithelial Cells Induced by Cladribine

PubMed Central

Chylińska-Wrzos, Patrycja; Lis-Sochocka, Marta; Bulak, Kamila; Jodłowska-Jędrych, Barbara

2014-01-01

Cladribine is a purine nucleoside analog which initiates the apoptotic mechanism within cells. Moreover, the available data confirms that cladribine, with the participation of the p53 protein, as well as the proapoptotic proteins from the Bcl-2 family, also induces the activation of the intrinsic apoptosis pathway. However, while there has been a lot of research devoted to the effect of cladribine on lymphatic system cells, little is known about the impact of cladribine on the reproductive system. The aim of our study was to evaluate apoptosis in oviduct epithelial cells sourced from 15 different female rats. In so doing, the sections were stained with caspases 3, 9, and 8. Results suggest that cladribine also induces apoptosis in the oviduct epithelial cells by way of the intrinsic pathway. Indeed, the discontinuing of the administration of cladribine leads to a reduction in the amount of apoptotic cells in the oviduct epithelium. PMID:25431797

Neferine reduces cisplatin-induced nephrotoxicity by enhancing autophagy via the AMPK/mTOR signaling pathway.

PubMed

Li, Hui; Tang, Yuling; Wen, Long; Kong, Xianglong; Chen, Xuelian; Liu, Ping; Zhou, Zhiguo; Chen, Wenhang; Xiao, Chenggen; Xiao, Ping; Xiao, Xiangcheng

2017-03-11

Cisplatin is one of the most effective chemotherapeutic agents; however, its clinical use is limited by serious side effects of which nephrotoxicity is the most important. Nephrotoxicity induced by cisplatin is closely associated with autophagy reduction and caspase activation. In this study, we investigated whether neferine, an autophagy inducer, had a protective effect against cisplatin-induced nephrotoxicity. In an in vitro cisplatin-induced nephrotoxicity model, we determined that neferine was able to induce autophagy and that pretreatment with neferine not only attenuated cisplatin-induced cell apoptosis but further activated cell autophagy. This pro-survival effect was abolished by the autophagic flux inhibitor chloroquine. Furthermore, neferine pretreatment activated the AMPK/mTOR pathway; however, pharmacological inhibition of AMPK abolished neferine-mediated autophagy and nephroprotection against cisplatin-induced apoptosis. Collectively, our findings suggest for the first time the possible protective mechanism of neferine, which is crucial for its further development as a potential therapeutic agent for cisplatin-induced nephrotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

Differential Costs of Two Distinct Resistance Mechanisms Induced by Different Herbivore Species in Arabidopsis1

PubMed Central

Reichelt, Michael; van Doorn, Arjen; Schuurink, Robert C.

2016-01-01

Plants respond to herbivory with the induction of resistance, mediated by distinct phytohormonal signaling pathways and their interactions. Phloem feeders are known to induce plant resistance via the salicylic acid pathway, whereas biting-chewing herbivores induce plant resistance mainly via the jasmonate pathway. Here, we show that a specialist caterpillar (biting-chewing herbivore) and a specialist aphid (phloem feeder) differentially induce resistance against Pieris brassicae caterpillars in Arabidopsis (Arabidopsis thaliana) plants. Caterpillar feeding induces resistance through the jasmonate signaling pathway that is associated with the induction of kaempferol 3,7-dirhamnoside, whereas aphid feeding induces resistance via a novel mechanism involving sinapoyl malate. The role of sinapoyl malate is confirmed through the use of a mutant compromised in the biosynthesis of this compound. Caterpillar-induced resistance is associated with a lower cost in terms of plant growth reduction than aphid-induced resistance. A strong constitutive resistance against P. brassicae caterpillars in combination with a strong growth attenuation in plants of a transfer DNA (T-DNA) insertion mutant of WRKY70 (wrky70) suggest that the WRKY70 transcription factor, a regulator of downstream responses mediated by jasmonate-salicylic acid signaling cross talk, is involved in the negative regulation of caterpillar resistance and in the tradeoff between growth and defense. In conclusion, different mechanisms of herbivore-induced resistance come with different costs, and a functional WRKY70 transcription factor is required for the induction of low-cost resistance. PMID:26603653

D4F alleviates macrophage-derived foam cell apoptosis by inhibiting the NF-κB-dependent Fas/FasL pathway.

PubMed

Tian, Hua; Yao, Shu-Tong; Yang, Na-Na; Ren, Jie; Jiao, Peng; Zhang, Xiangjian; Li, Dong-Xuan; Zhang, Gong-An; Xia, Zhen-Fang; Qin, Shu-Cun

2017-08-04

This study was designed to explore the protective effect of D4F, an apolipoprotein A-I mimetic peptide, on nuclear factor-κB (NF-κB)-dependent Fas/Fas ligand (FasL) pathway-mediated apoptosis in macrophages induced by oxidized low-density lipoprotein (ox-LDL). Our results showed that ox-LDL induced apoptosis, NF-κB P65 nuclear translocation and the upregulation of Fas/FasL pathway-related proteins, including Fas, FasL, Fas-associated death domain proteins (FADD), caspase-8 and caspase-3 in RAW264.7 macrophages, whereas silencing of Fas blocked ox-LDL-induced macrophage apoptosis. Furthermore, silencing of P65 attenuated macrophage apoptosis and the upregulation of Fas caused by ox-LDL, whereas P65 expression was not significantly affected by treatment with Fas siRNA. D4F attenuated the reduction of cell viability and the increase in lactate dehydrogenase leakage and apoptosis. Additionally, D4F inhibited ox-LDL-induced P65 nuclear translocation and upregulation of Fas/FasL pathway-related proteins in RAW264.7 cells and in atherosclerotic lesions of apoE -/- mice. However, Jo2, a Fas-activating monoclonal antibody, reversed the inhibitory effect of D4F on ox-LDL-induced cell apoptosis and upregulation of Fas, FasL and FADD. These data indicate that NF-κB mediates Fas/FasL pathway activation and apoptosis in macrophages induced by ox-LDL and that D4F protects macrophages from ox-LDL-induced apoptosis by suppressing the activation of NF-κB and the Fas/FasL pathway.

BECN1-dependent CASP2 incomplete autophagy induction by binding to rabies virus phosphoprotein.

PubMed

Liu, Juan; Wang, Hailong; Gu, Jinyan; Deng, Tingjuan; Yuan, Zhuangchuan; Hu, Boli; Xu, Yunbin; Yan, Yan; Zan, Jie; Liao, Min; DiCaprio, Erin; Li, Jianrong; Su, Shuo; Zhou, Jiyong

2017-04-03

Autophagy is an essential component of host immunity and used by viruses for survival. However, the autophagy signaling pathways involved in virus replication are poorly documented. Here, we observed that rabies virus (RABV) infection triggered intracellular autophagosome accumulation and results in incomplete autophagy by inhibiting autophagy flux. Subsequently, we found that RABV infection induced the reduction of CASP2/caspase 2 and the activation of AMP-activated protein kinase (AMPK)-AKT-MTOR (mechanistic target of rapamycin) and AMPK-MAPK (mitogen-activated protein kinase) pathways. Further investigation revealed that BECN1/Beclin 1 binding to viral phosphoprotein (P) induced an incomplete autophagy via activating the pathways CASP2-AMPK-AKT-MTOR and CASP2-AMPK-MAPK by decreasing CASP2. Taken together, our data first reveals a crosstalk of BECN1 and CASP2-dependent autophagy pathways by RABV infection.

Nonylphenol induced apoptosis and autophagy involving the Akt/mTOR pathway in prepubertal Sprague-Dawley male rats in vivo and in vitro.

PubMed

Huang, Wenting; Quan, Chao; Duan, Peng; Tang, Sha; Chen, Wei; Yang, Kedi

2016-12-12

This research explores the detrimental effect of nonylphenol (NP) to prepubertal Sprague-Dawley male rats in vivo and in vitro. Herein, forty-two 3-week-old rats were randomly divided into six groups, which were treated with NP (0, NAC, 25, 50, 100, 100+NACmg/kg/2d for 30 consecutive days) by intraperitoneal injection. NP induced a reduction in testosterone (15.58%, 17.23%, 13.38% in 25, 50, 100mg/kg group, respectively), triggered apoptosis related to oxidative stress, and disturbed mRNA and/or protein levels of PI3K, PTEN, PDK1, p-Akt, p-mTOR, p70S6K, caspase-3, LC3B. NP induced morphological abnormality in epididymal sperm (2.00-, 3.02-fold in 50, 100mg/kg group, respectively). Pretreatment with NAC, attenuated NP-induced ROS production; recovered testosterone in serum, and ameliorated toxic effect in epididymal sperm. Sertoli cells were isolated, purified, treated with NP (0, 10, 20, and 30μM) for 12h. NP disturbed mRNA and/or protein levels of caspase-3, cleave-caspase-3, LC3B involving the PI3K/Akt/mTOR pathway. It also decreased protein levels of ABP, FSHR, N-cadherin, transferrin, vimentin; disturbed the gene levels of all, but vimentin. Pretreatment with wortmannin, alleviated an NP-induced reduction in protein levels of PI3K and PTEN. In conclusion, excess NP exposure induces apoptosis and autophagy, causes reproductive lesions involving the PI3K/AKT/mTOR pathway both in vivo and in vitro. It also triggers oxidative stress and hormonal deficiency, reduces semen quality. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Mangiferin exerts hepatoprotective activity against D-galactosamine induced acute toxicity and oxidative/nitrosative stress via Nrf2–NFκB pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Joydeep; Ghosh, Jyotirmoy; Roy, Anandita

Mangiferin, a xanthone glucoside, is well known to exhibit antioxidant, antiviral, antitumor, anti-inflammatory and gene-regulatory effects. In the present study, we isolated mangiferin from the bark of Mangifera indica and assessed its beneficial role in galactosamine (GAL) induced hepatic pathophysiology. GAL (400 mg/kg body weight) exposed hepatotoxic rats showed elevation in the activities of serum ALP, ALT, levels of triglycerides, total cholesterol, lipid-peroxidation and reduction in the levels of serum total proteins, albumin and cellular GSH. Besides, GAL exposure (5 mM) in hepatocytes induced apoptosis and necrosis, increased ROS and NO production. Signal transduction studies showed that GAL exposure significantlymore » increased the nuclear translocation of NFκB and elevated iNOS protein expression. The same exposure also elevated TNF-α, IFN-γ, IL-1β, IL-6, IL-12, IL-18 and decreased IL-10 mRNA expressions. Furthermore, GAL also decreased the protein expression of Nrf2, NADPH:quinine oxidoreductase-1, heme oxygenase-1 and GSTα. However, mangiferin administration in GAL intoxicated rats or coincubation of hepatocytes with mangiferin significantly altered all these GAL-induced adverse effects. In conclusion, the hepatoprotective role of mangiferin was due to induction of antioxidant defense via the Nrf2 pathway and reduction of inflammation via NFκB inhibition. Highlights: ►Galactosamine induces hepatocytes death via oxidative and nitrosative stress. ►Mangiferin exerts hepatoprotective effect/antioxidant defense via Nrf2 pathway. ►Mangiferin exerts anti-inflammatory responses by inhibiting NF-κB. ►Mangiferin suppresses galactosamine-induced repression of IL-10 mRNA.« less

Lead (Pb) induced ATM-dependent mitophagy via PINK1/Parkin pathway.

PubMed

Gu, Xueyan; Qi, Yongmei; Feng, Zengxiu; Ma, Lin; Gao, Ke; Zhang, Yingmei

2018-07-01

Lead (Pb), a widely distributed environmental pollutant, is known to induce mitochondrial damage as well as autophagy in vitro and in vivo. In this study, we found that Pb could trigger mitophagy in both HEK293 cells and the kidney cortex of male Kunming mice. However, whether ataxia telangiectasis mutated (ATM) which is reported to be linked with PTEN-induced putative kinase 1 (PINK1)/Parkin pathway (a well-characterized mitophagic pathway) participates in the regulation of Pb-induced mitophagy and its exact role remains enigmatic. Our results indicated that Pb activated ATM in vitro and in vivo, and further in vitro studies showed that ATM could co-localize with PINK1 and Parkin in cytosol and interact with PINK1. Knockdown of ATM by siRNA blocked Pb-induced mitophagy even under the circumstance of enhanced accumulation of PINK1 and mitochondrial Parkin. Intriguingly, elevation instead of reduction in phosphorylation level of PINK1 and Parkin was observed in response to ATM knockdown and Pb did not contribute to the further increase of their phosphorylation level, implying that ATM indirectly regulated PINK1/Parkin pathway. These findings reveal a novel mechanism for Pb toxicity and suggest the regulatory importance of ATM in PINK1/Parkin-mediated mitophagy. Copyright © 2018 Elsevier B.V. All rights reserved.

mTORC1-Independent Reduction of Retinal Protein Synthesis in Type 1 Diabetes

PubMed Central

Losiewicz, Mandy K.; Pennathur, Subramaniam; Jefferson, Leonard S.; Kimball, Scot R.; Abcouwer, Steven F.; Gardner, Thomas W.

2014-01-01

Poorly controlled diabetes has long been known as a catabolic disorder with profound loss of muscle and fat body mass resulting from a simultaneous reduction in protein synthesis and enhanced protein degradation. By contrast, retinal structure is largely maintained during diabetes despite reduced Akt activity and increased rate of cell death. Therefore, we hypothesized that retinal protein turnover is regulated differently than in other insulin-sensitive tissues, such as skeletal muscle. Ins2Akita diabetic mice and streptozotocin-induced diabetic rats exhibited marked reductions in retinal protein synthesis matched by a concomitant reduction in retinal protein degradation associated with preserved retinal mass and protein content. The reduction in protein synthesis depended on both hyperglycemia and insulin deficiency, but protein degradation was only reversed by normalization of hyperglycemia. The reduction in protein synthesis was associated with diminished protein translation efficiency but, surprisingly, not with reduced activity of the mTORC1/S6K1/4E-BP1 pathway. Instead, diabetes induced a specific reduction of mTORC2 complex activity. These findings reveal distinctive responses of diabetes-induced retinal protein turnover compared with muscle and liver that may provide a new means to ameliorate diabetic retinopathy. PMID:24740573

The role of ARK in stress-induced apoptosis in Drosophila cells

PubMed Central

Zimmermann, Katja C.; Ricci, Jean-Ehrland; Droin, Nathalie M.; Green, Douglas R.

2002-01-01

The molecular mechanisms of apoptosis are highly conserved throughout evolution. The homologs of genes essential for apoptosis in Caenorhabditis elegans and Drosophila melanogaster have been shown to be important for apoptosis in mammalian systems. Although a homologue for CED-4/apoptotic protease-activating factor (Apaf)-1 has been described in Drosophila, its exact function and the role of the mitochondrial pathway in its activation remain unclear. Here, we used the technique of RNA interference to dissect apoptotic signaling pathways in Drosophila cells. Inhibition of the Drosophila CED-4/Apaf-1–related killer (ARK) homologue resulted in pronounced inhibition of stress-induced apoptosis, whereas loss of ARK did not protect the cells from Reaper- or Grim-induced cell death. Reduction of DIAP1 induced rapid apoptosis in these cells, whereas the inhibition of DIAP2 expression did not but resulted in increased sensitivity to stress-induced apoptosis; apoptosis in both cases was prevented by inhibition of ARK expression. Cells in which cytochrome c expression was decreased underwent apoptosis induced by stress stimuli, Reaper or Grim. These results demonstrate the central role of ARK in stress-induced apoptosis, which appears to act independently of cytochrome c. Apoptosis induced by Reaper or Grim can proceed via a distinct pathway, independent of ARK. PMID:11901172

Rescue of IL-1β-induced reduction of human neurogenesis by omega-3 fatty acids and antidepressants.

PubMed

Borsini, Alessandra; Alboni, Silvia; Horowitz, Mark A; Tojo, Luis M; Cannazza, Giuseppe; Su, Kuan-Pin; Pariante, Carmine M; Zunszain, Patricia A

2017-10-01

Both increased inflammation and reduced neurogenesis have been associated with the pathophysiology of major depression. We have previously described how interleukin-1 (IL-1) β, a pro-inflammatory cytokine increased in depressed patients, decreases neurogenesis in human hippocampal progenitor cells. Here, using the same human in vitro model, we show how omega-3 (ω-3) polyunsaturated fatty acids and conventional antidepressants reverse this reduction in neurogenesis, while differentially affecting the kynurenine pathway. We allowed neural cells to proliferate for 3days and further differentiate for 7days in the presence of IL-1β (10ng/ml) and either the selective serotonin reuptake inhibitor sertraline (1µM), the serotonin and norepinephrine reuptake inhibitor venlafaxine (1µM), or the ω-3 fatty acids eicosapentaenoic acid (EPA, 10µM) or docosahexaenoic acid (DHA, 10µM). Co-incubation with each of these compounds reversed the IL-1β-induced reduction in neurogenesis (DCX- and MAP2-positive neurons), indicative of a protective effect. Moreover, EPA and DHA also reversed the IL-1β-induced increase in kynurenine, as well as mRNA levels of indolamine-2,3-dioxygenase (IDO); while DHA and sertraline reverted the IL-1β-induced increase in quinolinic acid and mRNA levels of kynurenine 3-monooxygenase (KMO). Our results show common effects of monoaminergic antidepressants and ω-3 fatty acids on the reduction of neurogenesis caused by IL-1β, but acting through both common and different kynurenine pathway-related mechanisms. Further characterization of their individual properties will be of benefit towards improving a future personalized medicine approach. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

[Lactobacillus rhamnosus GG conditioned medium prevents E. coli meningitis by inhibiting nuclear factor-κB pathway].

PubMed

Zeng, Qing; He, Xiao-Long; Xiao, Han-Sheng; DU, Lei; Li, Yu-Jing; Chen, Le-Cheng; Tian, Hui-Wen; Huang, Sheng-He; Cao, Hong

2017-01-20

To investigate whether Lactobacillus rhamnosus GG conditioned medium(LGG-CM)has preventive effect against E. coli K1-induced neuropathogenicity in vitro by inhibiting nuclear factor-κB (NF-κB) signaling pathway. An in vitro blood-brain barrier (BBB) model was constructed using human brain microvascular endothelial cells (HBMECs). The effect of LGG-CM on E. coli-actived NF-κB signaling pathway was assayed using Western blotting. Invasion assay and polymorphonuclear leukocyte (PMN) transmigration assay were performed to explore whether LGG-CM could inhibit E. coli invasion and PMN transmigration across the BBB in vitro. The expressions of ZO-1 and CD44 were detected using Western blotting and immunofluorescence. The changes of trans-epithelial electric resistance (TEER) and bacterial translocation were determined to evaluate the BBB permeability. Pre-treament with LGG-CM inhibited E. coli-activated NF-κB signaling pathway in HBMECs and decreased the invasion of E. coli K1 and transmigration of PMN. Western blotting showed that LGG-CM could alleviate E. coli-induced up-regulation of CD44 and down-regulation of ZO-1 expressions in HBMECs. In addition, pre-treatment with LGG-CM alleviated E. coli K1-induced reduction of TEER and suppressed bacterial translocation across the BBB in vitro. LGG-CM can block E. coli-induced activation of NF-κB signaling pathway and thereby prevents E. coli K1-induced neuropathogenicity by decreasing E. coli K1 invasion rates and PMN transmigration.

CD147 induces up-regulation of vascular endothelial growth factor in U937-derived foam cells through PI3K/AKT pathway.

PubMed

Zong, JiaXin; Li, YunTian; Du, DaYong; Liu, Yang; Yin, YongJun

2016-11-01

Intraplaque angiogenesis has been recognized as an important risk factor for the rupture of advanced atherosclerotic plaques in recent years. CD147, also called Extracellular Matrix Metalloproteinase Inducer, has been found the ability to promote angiogenesis in many pathological conditions such as cancer diseases and rheumatoid arthritis via the up-regulation of vascular endothelial growth factor (VEGF), a critical mediator of angiogenesis. We investigated whether CD147 would also induce the up-regulation of VEGF in the foam cells formation process and explored the probable signaling pathway. The results showed the expression of CD147 and VEGF was significantly higher in U937-derived foam cells. After CD147 stealth siRNA transfection treatment, the production of VEGF was reduced depended on the inhibition efficiency of CD147 siRNAs.The special signaling pathway inhibitors LY294002, SP600125, SB203580 and U0126 were added to cultures respectively and the results showed LY294002 dose-dependently inhibited the expression of VEGF. The reduction of phospho-Akt was observed in both LY294002 and siRNA groups, suggested that the phosphatidylinositol 3-kinase/Akt pathway may be the probable signaling pathway underlying CD147 induced up-regulation of VEGF in U937-derived foam cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Pathophysiology of Post Transplant Hypertension in Kidney Transplant: Focus on Calcineurin Inhibitors Induced Oxidative Stress and Renal Sodium Retention and Implications with RhoA/Rho Kinase Pathway.

PubMed

Calò, Lorenzo A; Ravarotto, Verdiana; Simioni, Francesca; Naso, Elena; Marchini, Francesco; Bonfante, Luciana; Furian, Lucrezia; Rigotti, Paolo

2017-01-01

Post-transplant hypertension is a common occurrence during treatment with calcineurin inhibitors (CNIs) in kidney transplant population. The pathogenesis of vasoconstriction induced by CNIs involves vascular tone alterations and kidney sodium transport regulation. Among the factors involved a key role is played by the activation of intrarenal renin-angiotensin system with enhanced release of Angiotensin II (Ang II) and increase of oxidative stress. A common pathway between oxidative stress and hypertension induced by CNIs may be identified in the involvement of the activation of RhoA/Rho kinase pathway, key for the induction of hypertension and cardiovascular-renal remodeling, of the oxidative stress mediated increased nitric oxide (NO) metabolism and increased renal sodium retention via increased activity of thiazide-sensitive sodium chloride cotransporter (NCC) in the distal tubule. We examined literature data including those coming from our group regarding the role of oxidative stress and sodium retention in CNIs induced hypertension and their involvement in cardiovascular-renal remodeling. Based on the available data, we have provided support to the activation of RhoA/Rho kinase pathway as an important effector in the pathophysiology of CNIs induced post-transplant hypertension via activation of oxidative stress and sodium retention. Clarification of how the biochemical and molecular mechanisms that regulate the processes involved in CNIs induced post transplant hypertension work and interact, would provide further insights not only into the comprehension of the pathophysiology of CNIs induced post transplant hypertension but could also have a positive impact on the clinical ground through the identification of significant targets. Their specific pharmacologic targeting might have multiple beneficial effects on the whole cardiovascular-renal function. The demonstration that in kidney transplanted patients with CNIs induced post-transplanted hypertension, the treatment of hypertension with different antihypertensive drugs inducing a comparable blood pressure reduction but different effects for example on oxidative stress and oxidative stress related proteins and/or Rho kinase and sodium retention, could be helpful for the choice of the antihypertensive treatment in these patients which takes advantage from effects of these drugs beyond blood pressure reduction. © 2017 The Author(s). Published by S. Karger AG, Basel.

Identification of Sleep-Modulated Pathways Involved in Neuroprotection from Stroke.

PubMed

Pace, Marta; Baracchi, Francesca; Gao, Bo; Bassetti, Claudio

2015-11-01

Sleep deprivation (SDp) performed before stroke induces an ischemic tolerance state as observed in other forms of preconditioning. As the mechanisms underlying this effect are not well understood, we used DNA oligonucleotide microarray analysis to identify the genes and the gene-pathways underlying SDp preconditioning effects. Gene expression was analyzed 3 days after stroke in 4 experimental groups: (i) SDp performed before focal cerebral ischemia (IS) induction; (ii) SDp performed before sham surgery; (iii) IS without SDp; and (iv) sham surgery without SDp. SDp was performed by gentle handling during the last 6 h of the light period, and ischemia was induced immediately after. Basic sleep research laboratory. Stroke induced a massive alteration in gene expression both in sleep deprived and non-sleep deprived animals. However, compared to animals that underwent ischemia alone, SDp induced a general reduction in transcriptional changes with a reduction in the upregulation of genes involved in cell cycle regulation and immune response. Moreover, an upregulation of a new neuroendocrine pathway which included melanin concentrating hormone, glycoprotein hormones-α-polypeptide and hypocretin was observed exclusively in rats sleep deprived before stroke. Our data indicate that sleep deprivation before stroke reprogrammed the signaling response to injury. The inhibition of cell cycle regulation and inflammation are neuroprotective mechanisms reported also for other forms of preconditioning treatment, whereas the implication of the neuroendocrine function is novel and has never been described before. These results therefore provide new insights into neuroprotective mechanisms involved in ischemic tolerance mechanisms. © 2015 Associated Professional Sleep Societies, LLC.

The Antiviral Alkaloid Berberine Reduces Chikungunya Virus-Induced Mitogen-Activated Protein Kinase Signaling

PubMed Central

Thaa, Bastian; Amrun, Siti Naqiah; Simarmata, Diane; Rausalu, Kai; Nyman, Tuula A.; Merits, Andres; McInerney, Gerald M.; Ng, Lisa F. P.

2016-01-01

ABSTRACT Chikungunya virus (CHIKV) has infected millions of people in the tropical and subtropical regions since its reemergence in the last decade. We recently identified the nontoxic plant alkaloid berberine as an antiviral substance against CHIKV in a high-throughput screen. Here, we show that berberine is effective in multiple cell types against a variety of CHIKV strains, also at a high multiplicity of infection, consolidating the potential of berberine as an antiviral drug. We excluded any effect of this compound on virus entry or on the activity of the viral replicase. A human phosphokinase array revealed that CHIKV infection specifically activated the major mitogen-activated protein kinase (MAPK) signaling pathways extracellular signal-related kinase (ERK), p38 and c-Jun NH2-terminal kinase (JNK). Upon treatment with berberine, this virus-induced MAPK activation was markedly reduced. Subsequent analyses with specific inhibitors of these kinases indicated that the ERK and JNK signaling cascades are important for the generation of progeny virions. In contrast to specific MAPK inhibitors, berberine lowered virus-induced activation of all major MAPK pathways and resulted in a stronger reduction in viral titers. Further, we assessed the in vivo efficacy of berberine in a mouse model and measured a significant reduction of CHIKV-induced inflammatory disease. In summary, we demonstrate the efficacy of berberine as a drug against CHIKV and highlight the importance of the MAPK signaling pathways in the alphavirus infectious cycle. IMPORTANCE Chikungunya virus (CHIKV) is a mosquito-borne virus that causes severe and persistent muscle and joint pain and has recently spread to the Americas. No licensed drug exists to counter this virus. In this study, we report that the alkaloid berberine is antiviral against different CHIKV strains and in multiple human cell lines. We demonstrate that berberine collectively reduced the virus-induced activation of cellular mitogen-activated protein kinase signaling. The relevance of these signaling cascades in the viral life cycle was emphasized by specific inhibitors of these kinase pathways, which decreased the production of progeny virions. Berberine significantly reduced CHIKV-induced inflammatory disease in a mouse model, demonstrating efficacy of the drug in vivo. Overall, this work makes a strong case for pursuing berberine as a potential anti-CHIKV therapeutic compound and for exploring the MAPK signaling pathways as antiviral targets against alphavirus infections. PMID:27535052

Cannabidiol, a Cannabis sativa constituent, inhibits cocaine-induced seizures in mice: Possible role of the mTOR pathway and reduction in glutamate release.

PubMed

Gobira, Pedro H; Vilela, Luciano R; Gonçalves, Bruno D C; Santos, Rebeca P M; de Oliveira, Antonio C; Vieira, Luciene B; Aguiar, Daniele C; Crippa, José A; Moreira, Fabricio A

2015-09-01

Cannabidiol (CBD), a major non-psychotomimetic constituent of Cannabis sativa, has therapeutic potential for certain psychiatric and neurological disorders. Studies in laboratory animals and limited human trials indicate that CBD has anticonvulsant and neuroprotective properties. Its effects against cocaine neurotoxicity, however, have remained unclear. Thus, the present study tested the hypothesis that CBD protects against cocaine-induced seizures and investigated the underlying mechanisms. CBD (30 mg/kg) pre-treatment increased the latency and reduced the duration of cocaine (75 mg/kg)-induced seizures in mice. The CB1 receptor antagonist, AM251 (1 and 3mg/kg), and the CB2 receptor antagonist, AM630 (2 and 4 mg/kg), failed to reverse this protective effect, suggesting that alternative mechanisms are involved. Synaptosome studies with the hippocampus of drug-treated animals revealed that cocaine increases glutamate release, whereas CBD induces the opposite effect. Finally, the protective effect of this cannabinoid against cocaine-induced seizure was reversed by rapamycin (1 and 5mg/kg), an inhibitor of the mammalian target of rapamycin (mTOR) intracellular pathway. In conclusion, CBD protects against seizures in a model of cocaine intoxication. These effects possibly occur through activation of mTOR with subsequent reduction in glutamate release. CBD should be further investigated as a strategy for alleviating psychostimulant toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Gonadotropin-releasing hormone (GnRH) agonist triptorelin inhibits estradiol-induced serum response element (SRE) activation and c-fos expression in human endometrial, ovarian and breast cancer cells.

PubMed

Gründker, Carsten; Günthert, Andreas R; Hellriegel, Martin; Emons, Günter

2004-11-01

The majority of human endometrial (>80%), ovarian (>80%) and breast (>50%) cancers express GnRH receptors. Their spontaneous and epidermal growth-factor-induced proliferation is dose- and time-dependently reduced by treatment with GnRH and its agonists. In this study, we demonstrate that the GnRH agonist triptorelin inhibits estradiol (E2)-induced cancer cell proliferation. The proliferation of quiescent estrogen receptor alpha (ER alpha)-/ER beta-positive, but not of ER alpha-negative/ER beta-positive endometrial, ovarian and breast cancer cell lines, was significantly stimulated (P<0.001) (ANOVA) after treatment with E2 (10(-8) M). This effect was time- and dose-dependently antagonized by simultaneous treatment with triptorelin. The inhibitory effect was maximal at 10(-5) M concentration of triptorelin (P<0.001). In addition, we could show that, in ER alpha-/ER beta-positive cell lines, E2 induces activation of serum response element (SRE) and expression of the immediate early-response gene c-fos. These effects were blocked by triptorelin (P<0.001). E2-induced activation of estrogen-response element (ERE) was not affected by triptorelin. The transcriptional activation of SRE by E2 is due to ER alpha activation of the mitogen-activated protein kinase (MAPK) pathway. This pathway is impeded by GnRH, resulting in a reduction of E2-induced SRE activation and, in consequence, a reduction of E2-induced c-fos expression. This causes downregulation of E2-induced cancer cell proliferation.

TOR Pathway-Mediated Juvenile Hormone Synthesis Regulates Nutrient-Dependent Female Reproduction in Nilaparvata lugens (Stål)

PubMed Central

Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhou, Qiang

2016-01-01

The “target of rapamycin” (TOR) nutritional signaling pathway and juvenile hormone (JH) regulation of vitellogenesis has been known for a long time. However, the interplay between these two pathways regulating vitellogenin (Vg) expression remains obscure. Here, we first demonstrated the key role of amino acids (AAs) in activation of Vg synthesis and egg development in Nilaparvata lugens using chemically defined artificial diets. AAs induced the expression of TOR and S6K (S6 kinase), whereas RNAi-mediated silencing of these two TOR pathway genes and rapamycin application strongly inhibited the AAs-induced Vg synthesis. Furthermore, knockdown of Rheb (Ras homologue enriched in brain), TOR, S6K and application of rapamycin resulted in a dramatic reduction in the mRNA levels of jmtN (juvenile hormone acid methyltransferase, JHAMT). Application of JH III on the RNAi (Rheb and TOR) and rapamycin-treated females partially rescued the Vg expression. Conversely, knockdown of either jmtN or met (methoprene-tolerant, JH receptor) and application of JH III had no effects on mRNA levels of Rheb, TOR and S6K and phosphorylation of S6K. In summary, our results demonstrate that the TOR pathway induces JH biosynthesis that in turn regulates AAs-mediated Vg synthesis in N. lugens. PMID:27043527

Salicylic Acid and Ethylene Pathways Are Differentially Activated in Melon Cotyledons by Active or Heat-Denatured Cellulase from Trichoderma longibrachiatum

PubMed Central

Martinez, Christelle; Blanc, Frédéric; Le Claire, Emilie; Besnard, Olivier; Nicole, Michel; Baccou, Jean-Claude

2001-01-01

Infiltration of cellulase (EC 3.2.1.4) from Trichoderma longibrachiatum into melon (Cucumis melo) cotyledons induced several key defense mechanisms and hypersensitive reaction-like symptoms. An oxidative burst was observed 3 hours after treatment and was followed by activation of ethylene and salicylic acid (SA) signaling pathways leading to marked induction of peroxidase and chitinase activities. The treatment of cotyledons by heat-denatured cellulase also led to some induction of peroxidase and chitinase activities, but the oxidative burst and SA production were not observed. Co-infiltration of aminoethoxyvinil-glycine (an ethylene inhibitor) with the active cellulase did not affect the high increase of peroxidase and chitinase activities. In contrast, co-infiltration of aminoethoxyvinil-glycine with the denatured enzyme blocked peroxidase and chitinase activities. Our data suggest that the SA pathway (induced by the cellulase activity) and ethylene pathway (induced by heat-denatured and active protein) together coordinate the activation of defense mechanisms. We found a partial interaction between both signaling pathways since SA caused an inhibition of the ethylene production and a decrease in peroxidase activity when co-infiltrated with denatured cellulase. Treatments with active or denatured cellulase caused a reduction in powdery mildew (Sphaerotheca fuliginea) disease. PMID:11553761

TOR Pathway-Mediated Juvenile Hormone Synthesis Regulates Nutrient-Dependent Female Reproduction in Nilaparvata lugens (Stål).

PubMed

Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhou, Qiang

2016-03-28

The "target of rapamycin" (TOR) nutritional signaling pathway and juvenile hormone (JH) regulation of vitellogenesis has been known for a long time. However, the interplay between these two pathways regulating vitellogenin (Vg) expression remains obscure. Here, we first demonstrated the key role of amino acids (AAs) in activation of Vg synthesis and egg development in Nilaparvata lugens using chemically defined artificial diets. AAs induced the expression of TOR and S6K (S6 kinase), whereas RNAi-mediated silencing of these two TOR pathway genes and rapamycin application strongly inhibited the AAs-induced Vg synthesis. Furthermore, knockdown of Rheb (Ras homologue enriched in brain), TOR, S6K and application of rapamycin resulted in a dramatic reduction in the mRNA levels of jmtN (juvenile hormone acid methyltransferase, JHAMT). Application of JH III on the RNAi (Rheb and TOR) and rapamycin-treated females partially rescued the Vg expression. Conversely, knockdown of either jmtN or met (methoprene-tolerant, JH receptor) and application of JH III had no effects on mRNA levels of Rheb, TOR and S6K and phosphorylation of S6K. In summary, our results demonstrate that the TOR pathway induces JH biosynthesis that in turn regulates AAs-mediated Vg synthesis in N. lugens.

Interleukin-2-induced survival of natural killer (NK) cells involving phosphatidylinositol-3 kinase-dependent reduction of ceramide through acid sphingomyelinase, sphingomyelin synthase, and glucosylceramide synthase.

PubMed

Taguchi, Yoshimitsu; Kondo, Tadakazu; Watanabe, Mitsumasa; Miyaji, Michihiko; Umehara, Hisanori; Kozutsumi, Yasunori; Okazaki, Toshiro

2004-11-15

Interleukin 2 (IL-2) rescued human natural killer (NK) KHYG-1 cells from apoptosis along with a reduction of ceramide. Conversely, an increase of ceramide inhibited IL-2-rescued survival. IL-2 deprivation-induced activation of acid sphingomyelinase (SMase) and inhibition of glucosylceramide synthase (GCS) and sphingomyelin synthase (SMS) were normalized by IL-2 supplementation. A phosphatidyl inositol-3 (PI-3) kinase inhibitor, LY294002, inhibited IL-2-rescued survival, but a mitogen-activated protein kinase inhibitor, PD98059, and an inhibitor of Janus tyrosine kinase/signal transducer and activator of transcription pathway, AG490, did not. LY294002 inhibited IL-2-induced reduction of ceramide through activation of acid SMase and inhibition of GCS and SMS, suggesting the positive involvement of PI-3 kinase in ceramide reduction through enzymatic regulation. Indeed, a constitutively active PI-3 kinase enhanced growth rate and ceramide reduction through inhibition of acid SMase and activation of GCS and SMS. Further, LY294002 inhibited IL-2-induced changes of transcriptional level as well as mRNA and protein levels in acid SMase and GCS but did not affect the stability of the mRNAs. These results suggest that PI-3 kinase-dependent reduction of ceramide through regulation of acid SMase, GCS, and SMS plays a role in IL-2-rescued survival of NK cells.

Beta Catenin in Prostate Cancer Apoptosis

DTIC Science & Technology

2013-04-01

TRAIL-TZD antagonizes GSK3β and GSK3α pathways in these cells via up-regulating pGSK3βSer9 levels (indicating inhibition), and down-regulating...treatment which also showed that BIO can sensitize towards TRAIL-induced apoptosis (Fig 7B). Effect of TRAIL-TZD on GSK3β and GSK3α ...reduction of both total GSK3β and GSK3α expressions (see 16 hr and 24hr treatments). This indicated that TRAIL-TZD can antagonize GSK3β pathway by two

Inhibition of the Autophagy Pathway Synergistically Potentiates the Cytotoxic Activity of Givinostat (ITF2357) on Human Glioblastoma Cancer Stem Cells.

PubMed

Angeletti, Francesca; Fossati, Gianluca; Pattarozzi, Alessandra; Würth, Roberto; Solari, Agnese; Daga, Antonio; Masiello, Irene; Barbieri, Federica; Florio, Tullio; Comincini, Sergio

2016-01-01

Increasing evidence highlighted the role of cancer stem cells (CSCs) in the development of tumor resistance to therapy, particularly in glioblastoma (GBM). Therefore, the development of new therapies, specifically directed against GBM CSCs, constitutes an important research avenue. Considering the extended range of cancer-related pathways modulated by histone acetylation/deacetylation processes, we studied the anti-proliferative and pro-apoptotic efficacy of givinostat (GVS), a pan-histone deacetylase inhibitor, on cell cultures enriched in CSCs, isolated from nine human GBMs. We report that GVS induced a significant reduction of viability and self-renewal ability in all GBM CSC cultures; conversely, GVS exposure did not cause a significant cytotoxic activity toward differentiated GBM cells and normal mesenchymal human stem cells. Analyzing the cellular and molecular mechanisms involved, we demonstrated that GVS affected CSC viability through the activation of programmed cell death pathways. In particular, a marked stimulation of macroautophagy was observed after GVS treatment. To understand the functional link between GVS treatment and autophagy activation, different genetic and pharmacological interfering strategies were used. We show that the up-regulation of the autophagy process, obtained by deprivation of growth factors, induced a reduction of CSC sensitivity to GVS, while the pharmacological inhibition of the autophagy pathway and the silencing of the key autophagy gene ATG7 , increased the cell death rate induced by GVS. Altogether these findings suggest that autophagy represents a pro-survival mechanism activated by GBM CSCs to counteract the efficacy of the anti-proliferative activity of GVS. In conclusion, we demonstrate that GVS is a novel pharmacological tool able to target GBM CSC viability and its efficacy can be enhanced by autophagy inhibitory strategies.

Inhibition of the Autophagy Pathway Synergistically Potentiates the Cytotoxic Activity of Givinostat (ITF2357) on Human Glioblastoma Cancer Stem Cells

PubMed Central

Angeletti, Francesca; Fossati, Gianluca; Pattarozzi, Alessandra; Würth, Roberto; Solari, Agnese; Daga, Antonio; Masiello, Irene; Barbieri, Federica; Florio, Tullio; Comincini, Sergio

2016-01-01

Increasing evidence highlighted the role of cancer stem cells (CSCs) in the development of tumor resistance to therapy, particularly in glioblastoma (GBM). Therefore, the development of new therapies, specifically directed against GBM CSCs, constitutes an important research avenue. Considering the extended range of cancer-related pathways modulated by histone acetylation/deacetylation processes, we studied the anti-proliferative and pro-apoptotic efficacy of givinostat (GVS), a pan-histone deacetylase inhibitor, on cell cultures enriched in CSCs, isolated from nine human GBMs. We report that GVS induced a significant reduction of viability and self-renewal ability in all GBM CSC cultures; conversely, GVS exposure did not cause a significant cytotoxic activity toward differentiated GBM cells and normal mesenchymal human stem cells. Analyzing the cellular and molecular mechanisms involved, we demonstrated that GVS affected CSC viability through the activation of programmed cell death pathways. In particular, a marked stimulation of macroautophagy was observed after GVS treatment. To understand the functional link between GVS treatment and autophagy activation, different genetic and pharmacological interfering strategies were used. We show that the up-regulation of the autophagy process, obtained by deprivation of growth factors, induced a reduction of CSC sensitivity to GVS, while the pharmacological inhibition of the autophagy pathway and the silencing of the key autophagy gene ATG7, increased the cell death rate induced by GVS. Altogether these findings suggest that autophagy represents a pro-survival mechanism activated by GBM CSCs to counteract the efficacy of the anti-proliferative activity of GVS. In conclusion, we demonstrate that GVS is a novel pharmacological tool able to target GBM CSC viability and its efficacy can be enhanced by autophagy inhibitory strategies. PMID:27833530

DL-3-n-butylphthalide alleviates vascular cognitive impairment induced by chronic cerebral hypoperfusion by activating the Akt/Nrf2 signaling pathway in the hippocampus of rats.

PubMed

Qi, Qianqian; Xu, Jing; Lv, Peiyuan; Dong, Yanhong; Liu, Zhijuan; Hu, Ming; Xiao, Yining; Jia, Yanqiu; Jin, Wei; Fan, Mingyue; Zhang, Dandan; Meng, Nan

2018-04-13

Oxidative stress induced by chronic cerebral hypoperfusion (CCH) plays an important role in the pathogenesis of vascular cognitive impairment (VCI). The Akt/Nrf2 signaling pathway is one of the most important antioxidative stress pathways. To explore whether NBP (DL-3-n-butylphthalide) could alleviate VCI induced by CCH via activating the Akt/Nrf2 signaling pathway and modifying the levels of apoptosis-related proteins, adult male Sprague-Dawley rats were subjected to permanent occlusion of bilateral common carotid arteries (BCCAO) and treated either with vehicle or NBP (applied in two doses, 40 mg/kg and 80 mg/kg) while sham operated animals were treated with vehicle. Treatments were administered daily for 28 days. The obtained results indicate that both administrated doses of NBP significantly ameliorated the spatial learning and memory impairments as indicated by the Morris water maze test while Hematoxylin-Eosin staining revealed that morphological defects in the CA1 area of hippocampus were improved. Moreover, NBP reversed the BCCAO-induced downregulation of investigated oxidative stress-related proteins (p-Akt, t-Nrf2, n-Nrf2 and HO-1) along with the upregulation of pro-apoptotic molecule, Bax and reduction of the expression of anti-apoptotic protein, Bcl-2. According to presented results, NBP may have a protective effect against cognitive and morphological impairments induced by CCH via activation of Akt/Nrf2 signaling pathway and inhibition of apoptotic cascade. Copyright © 2017. Published by Elsevier B.V.

Dysfunction of different cellular degradation pathways contributes to specific β-amyloid42-induced pathologies.

PubMed

Ji, Xuan-Ru; Cheng, Kuan-Chung; Chen, Yu-Ru; Lin, Tzu-Yu; Cheung, Chun Hei Antonio; Wu, Chia-Lin; Chiang, Hsueh-Cheng

2018-03-01

The endosomal-lysosomal system (ELS), autophagy, and ubiquitin-proteasome system (UPS) are cellular degradation pathways that each play a critical role in the removal of misfolded proteins and the prevention of the accumulation of abnormal proteins. Recent studies on Alzheimer's disease (AD) pathogenesis have suggested that accumulation of aggregated β-amyloid (Aβ) peptides in the AD brain results from a dysfunction in these cellular clearance systems. However, the specific roles of these pathways in the removal of Aβ peptides and the pathogenesis underlying AD are unclear. Our in vitro and in vivo genetic approaches revealed that ELS mainly removed monomeric β-amyloid42 (Aβ42), while autophagy and UPS clear oligomeric Aβ42. Although overproduction of phosphatidylinositol 4-phosphate-5 increased Aβ42 clearance, it reduced the life span of Aβ42 transgenic flies. Our behavioral studies further demonstrated impaired autophagy and UPS-enhanced Aβ42-induced learning and memory deficits, but there was no effect on Aβ42-induced reduction in life span. Results from genetic fluorescence imaging showed that these pathways were damaged in the following order: UPS, autophagy, and finally ELS. The results of our study demonstrate that different degradation pathways play distinct roles in the removal of Aβ42 aggregates and in disease progression. These findings also suggest that pharmacologic treatments that are designed to stimulate cellular degradation pathways in patients with AD should be used with caution.-Ji, X.-R., Cheng, K.-C., Chen, Y.-R., Lin, T.-Y., Cheung, C. H. A., Wu, C.-L., Chiang, H.-C. Dysfunction of different cellular degradation pathways contributes to specific β-amyloid42-induced pathologies.

Selenium isotope fractionation during reduction by Fe(II)-Fe(III) hydroxide-sulfate (green rust)

USGS Publications Warehouse

Johnson, T.M.; Bullen, T.D.

2003-01-01

We have determined the extent of Se isotope fractionation induced by reduction of selenate by sulfate interlayered green rust (GRSO4), a Fe(II)-Fe(III) hydroxide-sulfate. This compound is known to reduce selenate to Se(0), and it is the only naturally relevant abiotic selenate reduction pathway documented to date. Se reduction reactions, when they occur in nature, greatly reduce Se mobility and bioavailability. Se stable isotope analysis shows promise as an indicator of Se reduction, and Se isotope fractionation by various Se reactions must be known in order to refine this tool. We measured the increase in the 80Se/76Se ratio of dissolved selenate as lighter isotopes were preferentially consumed during reduction by GRSO4. Six different experiments that used GRSO4 made by two methods, with varying solution compositions and pH, yielded identical isotopic fractionations. Regression of all the data yielded an instantaneous isotope fractionation of 7.36 ?? 0.24???. Selenate reduction by GRSO4 induces much greater isotopic fractionation than does bacterial selenate reduction. If selenate reduction by GRSO4 occurs in nature, it may be identifiable on the basis of its relatively large isotopic fractionation. ?? 2003 Elsevier Science Ltd.

Anaerobiosis Induced State Transition: A Non Photochemical Reduction of PQ Pool Mediated by NDH in Arabidopsis thaliana

PubMed Central

Tirupathi, Malavath; Subramanyam, Rajagopal

2012-01-01

Background Non photochemical reduction of PQ pool and mobilization of LHCII between PSII and PSI are found to be linked under abiotic stress conditions. The interaction of non photochemical reduction of PQ pool and state transitions associated physiological changes are critically important under anaerobic condition in higher plants. Methodology/Findings The present study focused on the effect of anaerobiosis on non-photochemical reduction of PQ pool which trigger state II transition in Arabidopsis thaliana. Upon exposure to dark-anaerobic condition the shape of the OJIP transient rise is completely altered where as in aerobic treated leaves the rise is unaltered. Rise in F o and F J was due to the loss of oxidized PQ pool as the PQ pool becomes more reduced. The increase in Fo′ was due to the non photochemical reduction of PQ pool which activated STN7 kinase and induced LHCII phosphorylation under anaerobic condition. Further, it was observed that the phosphorylated LHCII is migrated and associated with PSI supercomplex increasing its absorption cross-section. Furthermore, evidences from crr2-2 (NDH mutant) and pgr5 mutants (deficient in non NDH pathway of cyclic electron transport) have indicated that NDH is responsible for non photochemical reduction of the PQ pool. We propose that dark anaerobic condition accelerates production of reducing equivalents (such as NADPH by various metabolic pathways) which reduce PQ pool and is mediated by NDH leading to state II transition. Conclusions/Significance Anaerobic condition triggers non photochemical reduction of PQ pool mediated by NDH complex. The reduced PQ pool activates STN7 kinase leading to state II transition in A. thaliana. PMID:23185453

Nitrifier-induced denitrification is an important source of soil nitrous oxide and can be inhibited by a nitrification inhibitor 3,4-dimethylpyrazole phosphate.

PubMed

Shi, Xiuzhen; Hu, Hang-Wei; Zhu-Barker, Xia; Hayden, Helen; Wang, Juntao; Suter, Helen; Chen, Deli; He, Ji-Zheng

2017-12-01

Soil ecosystem represents the largest contributor to global nitrous oxide (N 2 O) production, which is regulated by a wide variety of microbial communities in multiple biological pathways. A mechanistic understanding of these N 2 O production biological pathways in complex soil environment is essential for improving model performance and developing innovative mitigation strategies. Here, combined approaches of the 15 N- 18 O labelling technique, transcriptome analysis, and Illumina MiSeq sequencing were used to identify the relative contributions of four N 2 O pathways including nitrification, nitrifier-induced denitrification (nitrifier denitrification and nitrification-coupled denitrification) and heterotrophic denitrification in six soils (alkaline vs. acid soils). In alkaline soils, nitrification and nitrifier-induced denitrification were the dominant pathways of N 2 O production, and application of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) significantly reduced the N 2 O production from these pathways; this is probably due to the observed reduction in the expression of the amoA gene in ammonia-oxidizing bacteria (AOB) in the DMPP-amended treatments. In acid soils, however, heterotrophic denitrification was the main source for N 2 O production, and was not impacted by the application of DMPP. Our results provide robust evidence that the nitrification inhibitor DMPP can inhibit the N 2 O production from nitrifier-induced denitrification, a potential significant source of N 2 O production in agricultural soils. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Astaxanthin Inhibits Acetaldehyde-Induced Cytotoxicity in SH-SY5Y Cells by Modulating Akt/CREB and p38MAPK/ERK Signaling Pathways.

PubMed

Yan, Tingting; Zhao, Yan; Zhang, Xia; Lin, Xiaotong

2016-03-10

Excessive alcohol consumption can lead to brain tissue damage and cognitive dysfunction. Acetaldehyde, the most toxic metabolite of ethanol, mediates the brain tissue damage and cognitive dysfunction induced by chronic excessive alcohol consumption. In this study, the effect of astaxanthin, a marine bioactive compound, on acetaldehyde-induced cytotoxicity was investigated in SH-SY5Y cells. It was found that astaxanthin protected cells from apoptosis by ameliorating the effect of acetaldehyde on the expression of Bcl-2 family proteins, preventing the reduction of anti-apoptotic protein Bcl-2 and the increase of pro-apoptotic protein Bak induced by acetaldehyde. Further analyses showed that astaxanthin treatment inhibited acetaldehyde-induced reduction of the levels of activated Akt and cyclic AMP-responsive element binding protein (CREB). Astaxanthin treatment also prevented acetaldehyde-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK) and decrease of the level of activated extracellular signal-regulated kinases (ERKs). Activation of Akt/CREB pathway promotes cell survival and is involved in the upregulation of Bcl-2 gene. P38MAPK plays a critical role in apoptotic events while ERKs mediates the inhibition of apoptosis. Thus, astaxanthin may inhibit acetaldehyde-induced apoptosis through promoting the activation of Akt/CREB and ERKs and blocking the activation of p38MAPK. In addition, astaxanthin treatment suppressed the oxidative stress induced by acetaldehyde and restored the antioxidative capacity of SH-SY5Y cells. Therefore, astaxanthin may protect cells against acetaldehyde-induced cytotoxicity through maintaining redox balance and modulating apoptotic and survival signals. The results suggest that astaxanthin treatment may be beneficial for preventing neurotoxicity associated with acetaldehyde and excessive alcohol consumption.

Arctigenin protects against ultraviolet-A-induced damage to stemness through inhibition of the NF-κB/MAPK pathway.

PubMed

Park, See-Hyoung; Cho, Jae Youl; Oh, Sae Woong; Kang, Mingyeong; Lee, Seung Eun; Yoo, Ju Ah; Jung, Kwangseon; Lee, Jienny; Lee, Sang Yeol; Lee, Jongsung

2018-02-25

The stemness of stem cells is negatively affected by ultraviolet A (UVA) irradiation. This study was performed to examine the effects of arctigenin on UVA-irradiation-induced damage to the stemness of human mesenchymal stem cells (hMSCs) derived from adipose tissue. The mechanisms of action of arctigenin were also investigated. A BrdU-incorporation assay demonstrated that arctigenin attenuated the UVA-induced reduction of the cellular proliferative potential. Arctigenin also increased the UVA-induced reduction in stemness of hMSCs by upregulating stemness-related genes such as SOX2, OCT4, and NANOG. In addition, the UVA-induced reduction in the mRNA expression level of hypoxia-inducible factor (HIF)-1α was significantly recovered by arctigenin. The antagonizing effect of arctigenin on UVA irradiation was mediated by reduced PGE 2 production through the inhibition of MAPKs (p42/44 MAPK, p38 MAPK, and JNK) and NF-κB. Overall, these findings suggest that arctigenin can ameliorate the reduced stemness of hMSCs induced by UVA irradiation. The effects of arctigenin are mediated by PGE 2 -cAMP signaling-dependent upregulation of HIF-1α. Therefore, arctigenin could be used as an antagonist to attenuate the effects of UVA irradiation. Copyright © 2018 Elsevier B.V. All rights reserved.

Rosuvastatin Treatment Affects Both Basal and Glucose-Induced Insulin Secretion in INS-1 832/13 Cells

PubMed Central

Salunkhe, Vishal A.; Elvstam, Olof; Eliasson, Lena; Wendt, Anna

2016-01-01

Rosuvastatin is a member of the statin family. Like the other statins it is prescribed to lower cholesterol levels and thereby reduce the risk of cardiovascular events. Rosuvastatin lowers the cholesterol levels by inhibiting the key enzyme 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) in the cholesterol producing mevalonate pathway. It has been recognized that apart from their beneficial lipid lowering effects, statins also exhibit diabetogenic properties. The molecular mechanisms behind these remain unresolved. To investigate the effects of rosuvastatin on insulin secretion, we treated INS-1 832/13 cells with varying doses (20 nM to 20 μM) of rosuvastatin for 48 h. At concentrations of 2 μM and above basal insulin secretion was significantly increased. Using diazoxide we could determine that rosuvastatin did not increase basal insulin secretion by corrupting the KATP channels. Glucose-induced insulin secretion on the other hand seemed to be affected differently at different rosuvastatin concentrations. Rosuvastatin treatment (20 μM) for 24–48 h inhibited voltage-gated Ca2+ channels, which lead to reduced depolarization-induced exocytosis of insulin-containing granules. At lower concentrations of rosuvastatin (≤ 2 μM) the stimulus-secretion coupling pathway was intact downstream of the KATP channels as assessed by the patch clamp technique. However, a reduction in glucose-induced insulin secretion could be observed with rosuvastatin concentrations as low as 200 nM. The inhibitory effects of rosuvastatin on glucose-induced insulin secretion could be reversed with mevalonate, but not squalene, indicating that rosuvastatin affects insulin secretion through its effects on the mevalonate pathway, but not through the reduction of cholesterol biosynthesis. Taken together, these data suggest that rosuvastatin has the potential to increase basal insulin secretion and reduce glucose-induced insulin secretion. The latter is possibly an unavoidable side effect of rosuvastatin treatment as it occurs through the same mechanisms as the lipid-lowering effects of the drug. PMID:26986474

TRAIL enhances paracetamol-induced liver sinusoidal endothelial cell death in a Bim- and Bid-dependent manner

PubMed Central

Badmann, A; Langsch, S; Keogh, A; Brunner, T; Kaufmann, T; Corazza, N

2012-01-01

Paracetamol (acetaminophen, APAP) is a universally used analgesic and antipyretic agent. Considered safe at therapeutic doses, overdoses cause acute liver damage characterized by centrilobular hepatic necrosis. One of the major clinical problems of paracetamol-induced liver disease is the development of hemorrhagic alterations. Although hepatocytes represent the main target of the cytotoxic effect of paracetamol overdose, perturbations within the endothelium involving morphological changes of liver sinusoidal endothelial cells (LSECs) have also been described in paracetamol-induced liver disease. Recently, we have shown that paracetamol-induced liver damage is synergistically enhanced by the TRAIL signaling pathway. As LSECs are constantly exposed to activated immune cells expressing death ligands, including TRAIL, we investigated the effect of TRAIL on paracetamol-induced LSEC death. We here demonstrate for the first time that TRAIL strongly enhances paracetamol-mediated LSEC death with typical features of apoptosis. Inhibition of caspases using specific inhibitors resulted in a strong reduction of cell death. TRAIL appears to enhance paracetamol-induced LSEC death via the activation of the pro-apoptotic BH3-only proteins Bid and Bim, which initiate the mitochondrial apoptotic pathway. Taken together this study shows that the liver endothelial layer, mainly LSECs, represent a direct target of the cytotoxic effect of paracetamol and that activation of TRAIL receptor synergistically enhances paracetamol-induced LSEC death via the mitochondrial apoptotic pathway. TRAIL-mediated acceleration of paracetamol-induced cell death may thus contribute to the pathogenesis of paracetamol-induced liver damage. PMID:23254290

Competing retention pathways of uranium upon reaction with Fe(II)

NASA Astrophysics Data System (ADS)

Massey, Michael S.; Lezama-Pacheco, Juan S.; Jones, Morris E.; Ilton, Eugene S.; Cerrato, José M.; Bargar, John R.; Fendorf, Scott

2014-10-01

Biogeochemical retention processes, including adsorption, reductive precipitation, and incorporation into host minerals, are important in contaminant transport, remediation, and geologic deposition of uranium. Recent work has shown that U can become incorporated into iron (hydr)oxide minerals, with a key pathway arising from Fe(II)-induced transformation of ferrihydrite, (Fe(OH)3·nH2O) to goethite (α-FeO(OH)); this is a possible U retention mechanism in soils and sediments. Several key questions, however, remain unanswered regarding U incorporation into iron (hydr)oxides and this pathway's contribution to U retention, including: (i) the competitiveness of U incorporation versus reduction to U(IV) and subsequent precipitation of UO2; (ii) the oxidation state of incorporated U; (iii) the effects of uranyl aqueous speciation on U incorporation; and, (iv) the mechanism of U incorporation. Here we use a series of batch reactions conducted at pH ∼7, [U(VI)] from 1 to 170 μM, [Fe(II)] from 0 to 3 mM, and [Ca] at 0 or 4 mM coupled with spectroscopic examination of reaction products of Fe(II)-induced ferrihydrite transformation to address these outstanding questions. Uranium retention pathways were identified and quantified using extended X-ray absorption fine structure (EXAFS) spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. Analysis of EXAFS spectra showed that 14-89% of total U was incorporated into goethite, upon reaction with Fe(II) and ferrihydrite. Uranium incorporation was a particularly dominant retention pathway at U concentrations ⩽50 μM when either uranyl-carbonato or calcium-uranyl-carbonato complexes were dominant, accounting for 64-89% of total U. With increasing U(VI) and Fe(II) concentrations, U(VI) reduction to U(IV) became more prevalent, but U incorporation remained a functioning retention pathway. These findings highlight the potential importance of U(V) incorporation within iron oxides as a retention process of U across a wide range of biogeochemical environments and the sensitivity of uranium retention processes to operative (bio)geochemical conditions.

The effect of natural antioxidants in cyclophosphamide-induced hepatotoxicity: Role of Nrf2/HO-1 pathway.

PubMed

Sherif, Iman O

2018-05-22

Hepatotoxicity induced by cyclophosphamide (Cyclo) is a major concern in clinical practice. This study was designed to investigate the possible cytoprotective effect of natural antioxidants as oleuropein and quercetin against Cyclo induced hepatotoxicity via the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. Male Wistar rats were randomly divided into six groups and treated for 10 days as follow: Group I (Normal control) received saline, group II (Oleu control): received orally oleuropein 30 mg/kg/day, group III (Quer control): administered orally quercetin 50 mg/kg/day, group IV (Cyclo): received saline and injected with single intraperitoneal (i.p) dose of Cyclo 200 mg/kg at day 5, group V (Oleu ttt): treated with oleuropein plus Cyclo i.p. injection at day 5, and group VI (Quer ttt): treated with quercetin plus Cyclo i.p. injection at day 5. Injection of Cyclo showed marked increase in serum transaminases and alkaline phosphatase, hepatic malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-⍺) levels along with significant reduction in hepatic reduced glutathione (GSH), superoxide dismutase (SOD), and catalase levels in addition to downregulation of hepatic Nrf2 and HO-1 expressions and reduction in hepatic nuclear Nrf2 binding activity when compared with normal group. Histopathological examination of Cyclo treated rats revealed hepatic damage. Both oleuropein and quercetin exhibited an improvement in the biochemical and histopathological findings. In conclusion, the natural antioxidants oleuropein and quercetin counteract the Cyclo induced hepatotoxicity through activation of Nrf2/HO-1 signaling pathway with subsequent suppression of oxidative stress and inflammation. Copyright © 2018 Elsevier B.V. All rights reserved.

Glucagon-like peptide-1 reduces pancreatic β-cell mass through hypothalamic neural pathways in high-fat diet-induced obese rats.

PubMed

Ando, Hisae; Gotoh, Koro; Fujiwara, Kansuke; Anai, Manabu; Chiba, Seiichi; Masaki, Takayuki; Kakuma, Tetsuya; Shibata, Hirotaka

2017-07-17

We examined whether glucagon-like peptide-1 (GLP-1) affects β-cell mass and proliferation through neural pathways, from hepatic afferent nerves to pancreatic efferent nerves via the central nervous system, in high-fat diet (HFD)-induced obese rats. The effects of chronic administration of GLP-1 (7-36) and liraglutide, a GLP-1 receptor agonist, on pancreatic morphological alterations, c-fos expression and brain-derived neurotrophic factor (BDNF) content in the hypothalamus, and glucose metabolism were investigated in HFD-induced obese rats that underwent hepatic afferent vagotomy (VgX) and/or pancreatic efferent sympathectomy (SpX). Chronic GLP-1 (7-36) administration to HFD-induced obese rats elevated c-fos expression and BDNF content in the hypothalamus, followed by a reduction in pancreatic β-cell hyperplasia and insulin content, thus resulting in improved glucose tolerance. These responses were abolished by VgX and SpX. Moreover, administration of liraglutide similarly activated the hypothalamic neural pathways, thus resulting in a more profound amelioration of glucose tolerance than native GLP-1 (7-36). These data suggest that GLP-1 normalizes the obesity-induced compensatory increase in β-cell mass and glucose intolerance through a neuronal relay system consisting of hepatic afferent nerves, the hypothalamus, and pancreatic efferent nerves.

The Neuroprotective Effects of Decursin Isolated from Angelica gigas Nakai Against Amyloid β-Protein-Induced Apoptosis in PC 12 Cells via a Mitochondria-Related Caspase Pathway.

PubMed

Li, Li; Du, Jikun; Zou, Liyi; Xia, Haishan; Wu, Tie; Kim, Yongho; Lee, Yongwoo

2015-08-01

Decursin, purified from Angelica gigas Nakai, has been proven to exert neuroprotective property. Previous study revealed decursin protected the PC12 cells from Aβ25-35-induced oxidative cytotoxicity. The present study aimed to investigate whether decursin could protect PC12 cells from apoptosis caused by Aβ. Our results indicated that pretreatment of PC12 cells with decursin significantly inhibited Aβ25-35-induced cytotoxicity and apoptosis. The mechanism of action is likely to reverse Aβ25-35-induced mitochondrial dysfunction, including the reduction of mitochondrial membrane potential, the inhibition of reactive oxygen species production, and the decrease of mitochondrial release of cytochrome c in PC12 cells. In addition, decursin significantly suppressed the activity of caspase-3 and moderated the ratio of Bcl-2/Bax induced by Aβ25-35. These findings indicate that decursin exerts a neuroprotective effect against Aβ25-35-induced neurotoxicity in PC12 cells, at least in part, via suppressing the mitochondrial pathway of cellular apoptosis.

Long-term administration of pyridostigmine attenuates pressure overload-induced cardiac hypertrophy by inhibiting calcineurin signalling.

PubMed

Lu, Yi; Zhao, Ming; Liu, Jin-Jun; He, Xi; Yu, Xiao-Jiang; Liu, Long-Zhu; Sun, Lei; Chen, Li-Na; Zang, Wei-Jin

2017-09-01

Cardiac hypertrophy is associated with autonomic imbalance, characterized by enhanced sympathetic activity and withdrawal of parasympathetic control. Increased parasympathetic function improves ventricular performance. However, whether pyridostigmine, a reversible acetylcholinesterase inhibitor, can offset cardiac hypertrophy induced by pressure overload remains unclear. Hence, this study aimed to determine whether pyridostigmine can ameliorate pressure overload-induced cardiac hypertrophy and identify the underlying mechanisms. Rats were subjected to either sham or constriction of abdominal aorta surgery and treated with or without pyridostigmine for 8 weeks. Vagal activity and cardiac function were determined using PowerLab. Cardiac hypertrophy was evaluated using various histological stains. Protein markers for cardiac hypertrophy were quantitated by Western blot and immunoprecipitation. Pressure overload resulted in a marked reduction in vagal discharge and a profound increase in cardiac hypertrophy index and cardiac dysfunction. Pyridostigmine increased the acetylcholine levels by inhibiting acetylcholinesterase in rats with pressure overload. Pyridostigmine significantly attenuated cardiac hypertrophy based on reduction in left ventricular weight/body weight, suppression of the levels of atrial natriuretic peptide, brain natriuretic peptide and β-myosin heavy chain, and a reduction in cardiac fibrosis. These effects were accompanied by marked improvement of cardiac function. Additionally, pyridostigmine inhibited the CaN/NFAT3/GATA4 pathway and suppressed Orai1/STIM1 complex formation. In conclusion, pressure overload resulted in cardiac hypertrophy, cardiac dysfunction and a significant reduction in vagal discharge. Pyridostigmine attenuated cardiac hypertrophy and improved cardiac function, which was related to improved cholinergic transmission efficiency (decreased acetylcholinesterase and increased acetylcholine), inhibition of the CaN/NFAT3/GATA4 pathway and suppression of the interaction of Orai1/STIM1. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

mTORC1-independent reduction of retinal protein synthesis in type 1 diabetes.

PubMed

Fort, Patrice E; Losiewicz, Mandy K; Pennathur, Subramaniam; Jefferson, Leonard S; Kimball, Scot R; Abcouwer, Steven F; Gardner, Thomas W

2014-09-01

Poorly controlled diabetes has long been known as a catabolic disorder with profound loss of muscle and fat body mass resulting from a simultaneous reduction in protein synthesis and enhanced protein degradation. By contrast, retinal structure is largely maintained during diabetes despite reduced Akt activity and increased rate of cell death. Therefore, we hypothesized that retinal protein turnover is regulated differently than in other insulin-sensitive tissues, such as skeletal muscle. Ins2(Akita) diabetic mice and streptozotocin-induced diabetic rats exhibited marked reductions in retinal protein synthesis matched by a concomitant reduction in retinal protein degradation associated with preserved retinal mass and protein content. The reduction in protein synthesis depended on both hyperglycemia and insulin deficiency, but protein degradation was only reversed by normalization of hyperglycemia. The reduction in protein synthesis was associated with diminished protein translation efficiency but, surprisingly, not with reduced activity of the mTORC1/S6K1/4E-BP1 pathway. Instead, diabetes induced a specific reduction of mTORC2 complex activity. These findings reveal distinctive responses of diabetes-induced retinal protein turnover compared with muscle and liver that may provide a new means to ameliorate diabetic retinopathy. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

RNAseq analysis reveals pathways and candidate genes associated with salinity tolerance in a spaceflight-induced wheat mutant.

PubMed

Xiong, Hongchun; Guo, Huijun; Xie, Yongdun; Zhao, Linshu; Gu, Jiayu; Zhao, Shirong; Li, Junhui; Liu, Luxiang

2017-06-02

Salinity stress has become an increasing threat to food security worldwide and elucidation of the mechanism for salinity tolerance is of great significance. Induced mutation, especially spaceflight mutagenesis, is one important method for crop breeding. In this study, we show that a spaceflight-induced wheat mutant, named salinity tolerance 1 (st1), is a salinity-tolerant line. We report the characteristics of transcriptomic sequence variation induced by spaceflight, and show that mutations in genes associated with sodium ion transport may directly contribute to salinity tolerance in st1. Furthermore, GO and KEGG enrichment analysis of differentially expressed genes (DEGs) between salinity-treated st1 and wild type suggested that the homeostasis of oxidation-reduction process is important for salt tolerance in st1. Through KEGG pathway analysis, "Butanoate metabolism" was identified as a new pathway for salinity responses. Additionally, key genes for salinity tolerance, such as genes encoding arginine decarboxylase, polyamine oxidase, hormones-related, were not only salt-induced in st1 but also showed higher expression in salt-treated st1 compared with salt-treated WT, indicating that these genes may play important roles in salinity tolerance in st1. This study presents valuable genetic resources for studies on transcriptome variation caused by induced mutation and the identification of salt tolerance genes in crops.

Creatine Monohydrate Enhances Energy Status and Reduces Glycolysis via Inhibition of AMPK Pathway in Pectoralis Major Muscle of Transport-Stressed Broilers.

PubMed

Zhang, Lin; Wang, Xiaofei; Li, Jiaolong; Zhu, Xudong; Gao, Feng; Zhou, Guanghong

2017-08-16

Creatine monohydrate (CMH) contributes to reduce transport-induced muscle rapid glycolysis and improve meat quality of broilers, but the underlying mechanism is still unknown. Therefore, this study aimed to investigate the molecular mechanisms underlying the ameliorative effects of CMH on muscle glycolysis metabolism of transported broilers during summer. The results showed that 3 h transport during summer elevated chicken live weight loss and plasma corticosterone concentration; decreased muscle concentrations of ATP, creatine, and energy charge value; increased muscle AMP concentration and AMP/ATP ratio; and upregulated muscle mRNA expression of LKB1 and AMPKα2, as well as protein expression of p-LKB1 Thr189 and p-AMPKα Thr172 , which subsequently resulted in rapid glycolysis in the pectoralis major muscle and consequent reduction of meat quality. Dietary addition of CMH at 1200 mg/kg ameliorated transport-induced rapid muscle glycolysis and reduction of meat quality via enhancement of the energy-buffering capacity of intramuscular phosphocreatine/creatine system and inhibition of AMPK pathway.

Blocking the 4-1BB Pathway Ameliorates Crystalline Silica-induced Lung Inflammation and Fibrosis in Mice

PubMed Central

Li, Chao; Du, Sitong; Lu, Yiping; Lu, Xiaowei; Liu, Fangwei; Chen, Ying; Weng, Dong; Chen, Jie

2016-01-01

Long term pulmonary exposure to crystalline silica leads to silicosis that manifests progressive interstitial fibrosis, eventually leading to respiratory failure and death. Despite efforts to eliminate silicosis, clinical cases continue to occur in both developing and developed countries. The exact mechanisms of crystalline silica-induced pulmonary fibrosis remain elusive. Herein, we find that 4-1BB is induced in response to crystalline silica injury in lungs and that it is highly expressed during development of experimental silicosis. Therefore, we explore the role of 4-1BB pathway during crystalline silica-induced lung injury and find that a specific inhibitor blocking the pathway could effectively alleviate crystalline silica-induced lung inflammation and subsequent pulmonary fibrosis in vivo. Compared to controls, the treated mice exhibited reduced Th1 and Th17 responses. The concentrations of pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF), including tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-17A following crystalline silica challenge were also reduced in inhibitor-treated mice. Although there was no significant alteration in Th2 cytokines of IL-4 and IL-13, another type of pro-fibrogenic cell, regulatory T cell (Treg) was significantly affected. In addition, one of the major participants in fibrogenesis, fibrocyte recruited less due to the blockade. Furthermore, we demonstrated the decreased fibrocyte recruitment was associated with chemokine reductions in lung. Our study discovers the 4-1BB pathway signaling enhances inflammatory response and promotes pulmonary fibrosis induced by crystalline silica. The findings here provide novel insights into the molecular events that control crystalline silica-induced lung inflammation and fibrosis through regulating Th responses and the recruitment of fibrocytes in crystalline silica-exposed lung. PMID:27698940

Blocking the 4-1BB Pathway Ameliorates Crystalline Silica-induced Lung Inflammation and Fibrosis in Mice.

PubMed

Li, Chao; Du, Sitong; Lu, Yiping; Lu, Xiaowei; Liu, Fangwei; Chen, Ying; Weng, Dong; Chen, Jie

2016-01-01

Long term pulmonary exposure to crystalline silica leads to silicosis that manifests progressive interstitial fibrosis, eventually leading to respiratory failure and death. Despite efforts to eliminate silicosis, clinical cases continue to occur in both developing and developed countries. The exact mechanisms of crystalline silica-induced pulmonary fibrosis remain elusive. Herein, we find that 4-1BB is induced in response to crystalline silica injury in lungs and that it is highly expressed during development of experimental silicosis. Therefore, we explore the role of 4-1BB pathway during crystalline silica-induced lung injury and find that a specific inhibitor blocking the pathway could effectively alleviate crystalline silica-induced lung inflammation and subsequent pulmonary fibrosis in vivo. Compared to controls, the treated mice exhibited reduced Th1 and Th17 responses. The concentrations of pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF), including tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-17A following crystalline silica challenge were also reduced in inhibitor-treated mice. Although there was no significant alteration in Th2 cytokines of IL-4 and IL-13, another type of pro-fibrogenic cell, regulatory T cell (Treg) was significantly affected. In addition, one of the major participants in fibrogenesis, fibrocyte recruited less due to the blockade. Furthermore, we demonstrated the decreased fibrocyte recruitment was associated with chemokine reductions in lung. Our study discovers the 4-1BB pathway signaling enhances inflammatory response and promotes pulmonary fibrosis induced by crystalline silica. The findings here provide novel insights into the molecular events that control crystalline silica-induced lung inflammation and fibrosis through regulating Th responses and the recruitment of fibrocytes in crystalline silica-exposed lung.

The pyrrolo-1,5-benzoxazepine, PBOX-15, enhances TRAIL-induced apoptosis by upregulation of DR5 and downregulation of core cell survival proteins in acute lymphoblastic leukaemia cells

PubMed Central

NATHWANI, SEEMA-MARIA; GREENE, LISA M.; BUTINI, STEFANIA; CAMPIANI, GIUSEPPE; WILLIAMS, D. CLIVE; SAMALI, AFSHIN; SZEGEZDI, EVA; ZISTERER, DANIELA M.

2016-01-01

Apoptotic defects are frequently associated with poor outcome in pediatric acute lymphoblastic leukaemia (ALL) hence there is an ongoing demand for novel strategies that counteract apoptotic resistance. The death ligand TRAIL (tumour necrosis factor-related apoptosis-inducing ligand) and its selective tumour receptor system has attracted exceptional clinical interest. However, many malignancies including ALL are resistant to TRAIL monotherapy. Tumour resistance can be overcome by drug combination therapy. TRAIL and its agonist antibodies are currently undergoing phase II clinical trials with established chemotherapeutics. Herein, we present promising therapeutic benefits in combining TRAIL with the selective anti-leukaemic agents, the pyrrolo-1,5-benzoxazepines (PBOXs) for the treatment of ALL. PBOX-15 synergistically enhanced apoptosis induced by TRAIL and a DR5-selective TRAIL variant in ALL-derived cells. PBOX-15 enhanced TRAIL-induced apoptosis by dual activation of extrinsic and intrinsic apoptotic pathways. The specific caspase-8 inhibitor, Z-IETD-FMK, identified the extrinsic pathway as the principal mode of apoptosis. We demonstrate that PBOX-15 can enhance TRAIL-induced apoptosis by upregulation of DR5, reduction of cellular mitochondrial potential, activation of the caspase cascade and downregulation of PI3K/Akt, c-FLIP, Mcl-1 and IAP survival pathways. Of note, the PI3K pathway inhibitor LY-294002 significantly enhanced the apoptotic potential of TRAIL and PBOX-15 validating the importance of Akt downregulation in the TRAIL/PBOX-15 synergistic combination. Considering the lack of cytotoxicity to normal cells and ability to downregulate several survival pathways, PBOX-15 may represent an effective agent for use in combination with TRAIL for the treatment of ALL. PMID:27176505

Propofol attenuates H2O2-induced oxidative stress and apoptosis via the mitochondria- and ER-medicated pathways in neonatal rat cardiomyocytes.

PubMed

Liu, Xue-Ru; Cao, Lu; Li, Tao; Chen, Lin-Lin; Yu, Yi-Yan; Huang, Wen-Jun; Liu, Li; Tan, Xiao-Qiu

2017-05-01

Previous studies have shown that propofol, an intravenous anesthetic commonly used in clinical practice, protects the myocardium from injury. Mitochondria- and endoplasmic reticulum (ER)-mediated oxidative stress and apoptosis are two important signaling pathways involved in myocardial injury and protection. The present study aimed to test the hypothesis that propofol could exert a cardio-protective effect via the above two pathways. Cultured neonatal rat cardiomyocytes were treated with culture medium (control group), H 2 O 2 at 500 μM (H 2 O 2 group), propofol at 50 μM (propofol group), and H 2 O 2 plus propofol (H 2 O 2  + propofol group), respectively. The oxidative stress, mitochondrial membrane potential (ΔΨm) and apoptosis of the cardiomyocytes were evaluated by a series of assays including ELISA, flow cytometry, immunofluorescence microscopy and Western blotting. Propofol significantly suppressed the H 2 O 2 -induced elevations in the activities of caspases 3, 8, 9 and 12, the ratio of Bax/Bcl-2, and cell apoptosis. Propofol also inhibited the H 2 O 2 -induced reactive oxygen species (ROS) generation, lactic dehydrogenase (LDH) release and mitochondrial transmembrane potential (ΔΨm) depolarization, and restored the H 2 O 2 -induced reductions of glutathione (GSH) and superoxide dismutase (SOD). In addition, propofol decreased the expressions of glucose-regulated protein 78 kDa (Grp78) and inositol-requiring enzyme 1α (IRE1α), two important signaling molecules in the ER-mediated apoptosis pathway. Propofol protects cardiomyocytes from H 2 O 2 -induced injury by inhibiting the mitochondria- and ER-mediated apoptosis signaling pathways.

Curcumin Protects Skin against UVB-Induced Cytotoxicity via the Keap1-Nrf2 Pathway: The Use of a Microemulsion Delivery System.

PubMed

Ben Yehuda Greenwald, Maya; Frušić-Zlotkin, Marina; Soroka, Yoram; Ben Sasson, Shmuel; Bitton, Ronit; Bianco-Peled, Havazelet; Kohen, Ron

2017-01-01

Curcumin was found to be beneficial in treating several skin pathologies and diseases, providing antioxidant protection due to its reducing properties and its electrophilic properties (the ability to activate the Nrf 2 pathway and induce phase II cytoprotective enzymes). Nevertheless, clinical applications of curcumin are being hampered by its insufficient solubility, chemical instability, and poor absorption, leading to low efficacy in preventing skin pathologies. These limitations can be overcome by using a nanotechnology-based delivery system. Here, we elucidated the possibility of using curcumin encapsulated in a microemulsion preserving its unique chemical structure. We also examined whether curcumin microemulsion would reduce UVB-induced toxicity in skin. A significant curcumin concentration was found in the human skin dermis following topical application of a curcumin microemulsion. Moreover, curcumin microemulsion enhanced the reduction of UV-induced cytotoxicity in epidermal cells, paving the way for other incorporated electrophiles in encapsulated form protecting skin against stress-related diseases.

Curcumin Protects Skin against UVB-Induced Cytotoxicity via the Keap1-Nrf2 Pathway: The Use of a Microemulsion Delivery System

PubMed Central

Ben Yehuda Greenwald, Maya; Frušić-Zlotkin, Marina; Soroka, Yoram; Ben Sasson, Shmuel; Bitton, Ronit; Bianco-Peled, Havazelet

2017-01-01

Curcumin was found to be beneficial in treating several skin pathologies and diseases, providing antioxidant protection due to its reducing properties and its electrophilic properties (the ability to activate the Nrf2 pathway and induce phase II cytoprotective enzymes). Nevertheless, clinical applications of curcumin are being hampered by its insufficient solubility, chemical instability, and poor absorption, leading to low efficacy in preventing skin pathologies. These limitations can be overcome by using a nanotechnology-based delivery system. Here, we elucidated the possibility of using curcumin encapsulated in a microemulsion preserving its unique chemical structure. We also examined whether curcumin microemulsion would reduce UVB-induced toxicity in skin. A significant curcumin concentration was found in the human skin dermis following topical application of a curcumin microemulsion. Moreover, curcumin microemulsion enhanced the reduction of UV-induced cytotoxicity in epidermal cells, paving the way for other incorporated electrophiles in encapsulated form protecting skin against stress-related diseases. PMID:28757910

Mechanisms of direct inhibition of the respiratory sulfate-reduction pathway by (per)chlorate and nitrate.

PubMed

Carlson, Hans K; Kuehl, Jennifer V; Hazra, Amrita B; Justice, Nicholas B; Stoeva, Magdalena K; Sczesnak, Andrew; Mullan, Mark R; Iavarone, Anthony T; Engelbrektson, Anna; Price, Morgan N; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

2015-06-01

We investigated perchlorate (ClO(4)(-)) and chlorate (ClO(3)(-)) (collectively (per)chlorate) in comparison with nitrate as potential inhibitors of sulfide (H(2)S) production by mesophilic sulfate-reducing microorganisms (SRMs). We demonstrate the specificity and potency of (per)chlorate as direct SRM inhibitors in both pure cultures and undefined sulfidogenic communities. We demonstrate that (per)chlorate and nitrate are antagonistic inhibitors and resistance is cross-inducible implying that these compounds share at least one common mechanism of resistance. Using tagged-transposon pools we identified genes responsible for sensitivity and resistance in Desulfovibrio alaskensis G20. We found that mutants in Dde_2702 (Rex), a repressor of the central sulfate-reduction pathway were resistant to both (per)chlorate and nitrate. In general, Rex derepresses its regulon in response to increasing intracellular NADH:NAD(+) ratios. In cells in which respiratory sulfate reduction is inhibited, NADH:NAD(+) ratios should increase leading to derepression of the sulfate-reduction pathway. In support of this, in (per)chlorate or nitrate-stressed wild-type G20 we observed higher NADH:NAD(+) ratios, increased transcripts and increased peptide counts for genes in the core Rex regulon. We conclude that one mode of (per)chlorate and nitrate toxicity is as direct inhibitors of the central sulfate-reduction pathway. Our results demonstrate that (per)chlorate are more potent inhibitors than nitrate in both pure cultures and communities, implying that they represent an attractive alternative for controlling sulfidogenesis in industrial ecosystems. Of these, perchlorate offers better application logistics because of its inhibitory potency, solubility, relative chemical stability, low affinity for mineral cations and high mobility in environmental systems.

Resistance to excitotoxin-induced seizures and neuronal death in mice lacking the preprotachykinin A gene.

PubMed

Liu, H; Cao, Y; Basbaum, A I; Mazarati, A M; Sankar, R; Wasterlain, C G

1999-10-12

Epileptic seizures are associated with increases in hippocampal excitability, but the mechanisms that render the hippocampus hyperexcitable chronically (in epilepsy) or acutely (in status epilepticus) are poorly understood. Recent evidence suggests that substance P (SP), a peptide that has been implicated in cardiovascular function, inflammatory responses, and nociception, also contributes to hippocampal excitability and status epilepticus, in part by enhancing glutamate release. Here we report that mice with disruption of the preprotachykinin A gene, which encodes SP and neurokinin A, are resistant to kainate excitoxicity. The mice show a reduction in the duration and severity of seizures induced by kainate or pentylenetetrazole, and both necrosis and apoptosis of hippocampal neurons are prevented. Although kainate induced the expression of bax and caspase 3 in the hippocampus of wild-type mice, these critical intracellular mediators of cell death pathways were not altered by kainate injection in the mutant mice. These results indicate that the reduction of seizure activity and the neuroprotection observed in preprotachykinin A null mice are caused by the extinction of a SP/neurokinin A-mediated signaling pathway that is activated by seizures. They suggest that these neurokinins are critical to the control of hippocampal excitability, hippocampal seizures, and hippocampal vulnerability.

Metabolic pathways for photobiological hydrogen production by nitrogenase- and hydrogenase-containing unicellular cyanobacteria Cyanothece.

PubMed

Skizim, Nicholas J; Ananyev, Gennady M; Krishnan, Anagha; Dismukes, G Charles

2012-01-20

Current biotechnological interest in nitrogen-fixing cyanobacteria stems from their robust respiration and capacity to produce hydrogen. Here we quantify both dark- and light-induced H(2) effluxes by Cyanothece sp. Miami BG 043511 and establish their respective origins. Dark, anoxic H(2) production occurs via hydrogenase utilizing reductant from glycolytic catabolism of carbohydrates (autofermentation). Photo-H(2) is shown to occur via nitrogenase and requires illumination of PSI, whereas production of O(2) by co-illumination of PSII is inhibitory to nitrogenase above a threshold pO(2). Carbohydrate also serves as the major source of reductant for the PSI pathway mediated via nonphotochemical reduction of the plastoquinone pool by NADH dehydrogenases type-1 and type-2 (NDH-1 and NDH-2). Redirection of this reductant flux exclusively through the proton-coupled NDH-1 by inhibition of NDH-2 with flavone increases the photo-H(2) production rate by 2-fold (at the expense of the dark-H(2) rate), due to production of additional ATP (via the proton gradient). Comparison of photobiological hydrogen rates, yields, and energy conversion efficiencies reveals opportunities for improvement.

Involvement of reactive oxygen species/c-Jun NH{sub 2}-terminal kinase pathway in kotomolide A induces apoptosis in human breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, P.-L.; Chen, C.-Y.; Tzeng, T.-F.

2008-06-01

The anticancer effects of kotomolide A (KTA), a new butanolide constituent isolated from the leaves of Cinnamomum kotoense (Lauraceae), on the two human breast cancer cell lines MCF-7 and MDA-MB-231, were first investigated in our study. KTA exhibited selectively antiproliferative effects in cancer cell lines without showing any toxicity in normal mammary epithelial cells. Treatment of cancer cells with KTA to trigger G2/M phase arrest was associated with increased p21/WAF1 levels and reduced amounts of cyclin A, cyclin B1, cdc2 and cdc25C. KTA induced cancer cell death treatment by triggering mitochondrial and death receptor 5 (DR5) apoptotic pathways, but didmore » not act on the Fas receptor. Exposure of MCF-7 and MDA-MB-231 cells to KTA resulted in cellular glutathione reduction and ROS generation, accompanied by JNK activation and apoptosis. Both antioxidants, NAC and catalase, significantly decreased apoptosis by inhibiting the phosphorylation of JNK and subsequently triggering DR5 cell death pathways. The reduction of JNK expression by siRNA decreased KTA-mediated Bim cleavage, DR5 upregulation and apoptosis. Furthermore, daily KTA i.p. injections in nude mice with MDA-MB-231 s.c. tumors resulted in a 50% decrease of mean tumor volume, compared with vehicle-treated controls. Taken together, the data show that cell death of breast cancer cells in response to KTA is dependent upon ROS generation and JNK activation, triggering intrinsic and extrinsic apoptotic pathways. The ROS/JNK pathway could be a useful target for novel approaches in breast cancer chemotherapy.« less

Pepsin-pancreatin protein hydrolysates from extruded amaranth inhibit markers of atherosclerosis in LPS-induced THP-1 macrophages-like human cells by reducing expression of proteins in LOX-1 signaling pathway

PubMed Central

2014-01-01

Background Atherosclerosis is considered a progressive disease that affects arteries that bring blood to the heart, to the brain and to the lower end. It derives from endothelial dysfunction and inflammation, which play an important role in the thrombotic complications of atherosclerosis. Cardiovascular disease is the leading cause of death around the world and one factor that can contribute to its progression and prevention is diet. Our previous study found that amaranth hydrolysates inhibited LPS-induced inflammation in human and mouse macrophages by preventing activation of NF-κB signaling. Furthermore, extrusion improved the anti-inflammatory effect of amaranth protein hydrolysates in both cell lines, probably attributed to the production of bioactive peptides during processing. Therefore, the objective of this study was to compare the anti-atherosclerotic potential of pepsin-pancreatin hydrolysates from unprocessed and extruded amaranth in THP-1 lipopolysaccharide-induced human macrophages and suggest the mechanism of action. Results Unprocessed amaranth hydrolysate (UAH) and extruded amaranth hydrolysate (EAH) showed a significant reduction in the expression of interleukin-4 (IL-4) (69% and 100%, respectively), interleukin-6 (IL-6) (64% and 52%, respectively), interleukin-22 (IL-22) (55% and 70%, respectively). Likewise, UAH and EAH showed a reduction in the expression of monocyte-chemo attractant protein-1 (MCP-1) (35% and 42%, respectively), transferrin receptor-1 (TfR-1) (48% and 61%, respectively), granulocyte-macrophage colony-stimulating factor (GM-CSF) (59% and 63%, respectively), and tumor necrosis factor-α (TNF-α) (60% and 63%, respectively). Also, EAH reduced the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) (27%), intracellular adhesion molecule-1 (ICAM-1) (28%) and matrix metalloproteinase-9 (MMP-9) (19%), important molecular markers in the atherosclerosis pathway. EAH, led to a reduction of 58, 52 and 79% for LOX-1, ICAM-1 and MMP-9, respectively, by confocal microscopy. Conclusions Extruded amaranth hydrolysate showed potential anti-atherosclerotic effect in LPS-induced THP-1 human macrophage-like cells by reducing the expression of proteins associated with LOX-1 signaling pathway. PMID:24891839

Effect of caffeine coadministration and of nitric oxide synthesis inhibition on the antinociceptive action of ketorolac.

PubMed

López-Muñoz, F J; Castañeda-Hernández, G; Flores-Murrieta, F J; Granados-Soto, V

1996-07-25

The effects of caffeine and nitric oxide synthesis inhibition on the antinociceptive action of ketorolac were assessed using the pain-induced functional impairment model in the rat. Nociception was induced by the intra-articular injection of uric acid. Ketorolac, but not caffeine, produced an antinociceptive effect which was reduced by NG nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis. Caffeine coadministration potentiated the ketorolac effect. L-NAME induced a dose-dependent reduction of this potentiation. The results suggest the participation of the L-arginine-nitric oxide-cyclic GMP pathway in the caffeine potentiation of ketorolac-induced antinociception.

KRE5 Suppression Induces Cell Wall Stress and Alternative ER Stress Response Required for Maintaining Cell Wall Integrity in Candida glabrata

PubMed Central

Sasaki, Masato; Ito, Fumie; Aoyama, Toshio; Sato-Okamoto, Michiyo; Takahashi-Nakaguchi, Azusa; Chibana, Hiroji; Shibata, Nobuyuki

2016-01-01

The maintenance of cell wall integrity in fungi is required for normal cell growth, division, hyphae formation, and antifungal tolerance. We observed that endoplasmic reticulum stress regulated cell wall integrity in Candida glabrata, which possesses uniquely evolved mechanisms for unfolded protein response mechanisms. Tetracycline-mediated suppression of KRE5, which encodes a predicted UDP-glucose:glycoprotein glucosyltransferase localized in the endoplasmic reticulum, significantly increased cell wall chitin content and decreased cell wall β-1,6-glucan content. KRE5 repression induced endoplasmic reticulum stress-related gene expression and MAP kinase pathway activation, including Slt2p and Hog1p phosphorylation, through the cell wall integrity signaling pathway. Moreover, the calcineurin pathway negatively regulated cell wall integrity, but not the reduction of β-1,6-glucan content. These results indicate that KRE5 is required for maintaining both endoplasmic reticulum homeostasis and cell wall integrity, and that the calcineurin pathway acts as a regulator of chitin-glucan balance in the cell wall and as an alternative mediator of endoplasmic reticulum stress in C. glabrata. PMID:27548283

Neurotoxicity induced by dexamethasone in the human neuroblastoma SH-SY5Y cell line can be prevented by folic acid.

PubMed

Budni, J; Romero, A; Molz, S; Martín-de-Saavedra, M D; Egea, J; Del Barrio, L; Tasca, C I; Rodrigues, A L S; López, M G

2011-09-08

Folic acid (folate) is a vitamin of the B-complex group that is essential for cell replication. Folate is a major determinant of one-carbon metabolism, in which S-adenosylmethionine donates methyl groups that are crucial for neurological function. Many roles for folic acid have been reported, including neuroprotective and antidepressant properties. On the other hand, increased concentrations of corticoids have proven neurotoxic effects and hypersecretion of glucocorticoids has been linked to different mood disorders. The purpose of this study was to investigate the potential protective effect of folic acid on dexamethasone-induced cellular death in SH-SY5Y neuroblastoma cell line and the possible intracellular signaling pathway involved in such effect. Exposure to 1 mM dexamethasone for 48 h caused a significant reduction of cell viability measured as 3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) reduction. Exposure of SH-SY5Y cells for 72 h to increasing concentrations of folate (1-300 μM) was not cytotoxic. However, pretreatment with folate (10-300 μM) reduced dexamethasone-induced toxicity in a significant manner. To explore the putative intracellular signaling pathways implicated in the protective effect of folate we used different protein kinase inhibitors. The protective effect of folic acid on dexamethasone-induced neurotoxicity was reversed by the phosphatidylinositol-3 kinase/Akt (PI3K/Akt, LY294002), Ca²⁺/Calmodulin-dependent protein kinase II (CaMKII, KN-93), and protein kinase A (PKA, H-89) inhibitors, but not the mitogen-activated protein/extracellular signal-regulated kinase (MEK1/2, PD98059) and protein kinase C (PKC, chelerythrine) inhibitors. In conclusion, the results of this study show that folic acid can protect against dexamethasone-induced neurotoxicity and its protective mechanism is related to a signaling pathway that involves PI3K/Akt, CaMKII, and PKA. Copyright © 2011. Published by Elsevier Ltd.

Role of the cyclooxygenase 2-thromboxane pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced decrease in mesencephalic vein blood flow in the zebrafish embryo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teraoka, Hiroki; Kubota, Akira; Dong, Wu

2009-01-01

Previously, we reported that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) evoked developmental toxicity required activation of aryl hydrocarbon receptor type 2 (AHR2), using zebrafish embryos. However, the downstream molecular targets of AHR2 activation are largely unknown and are the focus of the present investigation. TCDD induces cyclooxygenase 2 (COX2), a rate-limiting enzyme for prostaglandin synthesis in certain cells. In the present study, we investigated the role of the COX2-thromboxane pathway in causing a specific endpoint of TCDD developmental toxicity in the zebrafish embryo, namely, a decrease in regional blood flow in the dorsal midbrain. It was found that the TCDD-induced reduction in mesencephalic veinmore » blood flow was markedly inhibited by selective COX2 inhibitors, NS-398 and SC-236, and by a general COX inhibitor, indomethacin, but not by a selective COX1 inhibitor, SC-560. Gene knock-down of COX2 by two different types of morpholino antisense oligonucleotides, but not by their negative homologs, also protected the zebrafish embryos from mesencephalic vein circulation failure caused by TCDD. This inhibitory effect of TCDD on regional blood flow in the dorsal midbrain was also blocked by selective antagonists of the thromboxane receptor (TP). Treatment of control zebrafish embryos with a TP agonist also caused a reduction in mesencephalic vein blood flow and it too was blocked by a TP antagonist, without any effect on trunk circulation. Finally, gene knock-down of thromboxane A synthase 1 (TBXS) with morpholinos but not by the morpholinos' negative homologs provided significant protection against TCDD-induced mesencephalic circulation failure. Taken together, these results point to a role of the prostanoid synthesis pathway via COX2-TBXS-TP in the local circulation failure induced by TCDD in the dorsal midbrain of the zebrafish embryo.« less

The Interactions Between Kynurenine, Folate, Methionine and Pteridine Pathways in Obesity.

PubMed

Engin, Ayse Basak; Engin, Atilla

2017-01-01

Obesity activates both innate and adaptive immune responses in adipose tissue. Elevated levels of eosinophils with depression of monocyte and neutrophil indicate the deficiencies in the immune system of morbidly obese individuals. Actually, adipose tissue macrophages are functional antigen-presenting cells that promote the proliferation of interferon-gamma (IFN-gamma)-producing CD4+ T cells in adipose tissue of obese subjects. Eventually, diet-induced obesity is associated with the loss of tissue homeostasis and development of type 1 inflammatory responses in visceral adipose tissue. Activity of inducible indoleamine 2,3-dioxygenase-1 (IDO-1) plays a major role under pro-inflammatory, IFN-gamma dominated settings. One of the two rate-limiting enzymes which can metabolize tryptophan to kynurenine is IDO-1. Tumor necrosis factor-alpha (TNF-alpha) correlates with IDO-1 in adipose compartments. Actually, IDO-1-mediated tryptophan catabolism due to chronic immune activation is the cause of reduced tryptophan plasma levels and be considered as the driving force for food intake in morbidly obese patients. Thus, decrease in plasma tryptophan levels and subsequent reduction in serotonin (5-HT) production provokes satiety dysregulation that leads to increased caloric uptake and obesity. However, after bariatric surgery, weight reduction does not lead to normalization of IDO-1 activity. Furthermore, there is a connection between arginine and tryptophan metabolic pathways in the generation of reactive nitrogen intermediates. Hence, abdominal obesity is associated with vascular endothelial dysfunction and reduced nitric oxide (NO) availability. IFN-gamma-induced activation of the inducible nitric oxide synthase (iNOS) and dissociation of endothelial adenosine monophosphate activated protein kinase (AMPK)- phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt)- endothelial NO synthase (eNOS) pathway enhances oxidative stress production secondary to high-fat diet. Thus, reduced endothelial NO availability correlates with the increase in plasma non-esterified fatty acids and triglycerides levels. Additionally, in obese patients, folate-deficiency leads to hyperhomocysteinemia. Folic acid confers protection against hyperhomocysteinemia-induced oxidative stress.

Smoking-related microRNAs and mRNAs in human peripheral blood mononuclear cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Ming-Wei

Teenager smoking is of great importance in public health. Functional roles of microRNAs have been documented in smoke-induced gene expression changes, but comprehensive mechanisms of microRNA-mRNA regulation and benefits remained poorly understood. We conducted the Teenager Smoking Reduction Trial (TSRT) to investigate the causal association between active smoking reduction and whole-genome microRNA and mRNA expression changes in human peripheral blood mononuclear cells (PBMC). A total of 12 teenagers with a substantial reduction in smoke quantity and a decrease in urine cotinine/creatinine ratio were enrolled in genomic analyses. In Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA), differentially expressedmore » genes altered by smoke reduction were mainly associated with glucocorticoid receptor signaling pathway. The integrative analysis of microRNA and mRNA found eleven differentially expressed microRNAs negatively correlated with predicted target genes. CD83 molecule regulated by miR-4498 in human PBMC, was critical for the canonical pathway of communication between innate and adaptive immune cells. Our data demonstrated that microRNAs could regulate immune responses in human PBMC after habitual smokers quit smoking and support the potential translational value of microRNAs in regulating disease-relevant gene expression caused by tobacco smoke. - Highlights: • We conducted a smoke reduction trial program and investigated the causal relationship between smoke and gene regulation. • MicroRNA and mRNA expression changes were examined in human PBMC. • MicroRNAs are important in regulating disease-causal genes after tobacco smoke reduction.« less

Profound and Rapid Reduction in Body Temperature Induced by the Melanocortin Receptor Agonists

PubMed Central

Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-01-01

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5′AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII’s effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. PMID:25065745

Attenuation of Aβ{sub 25–35}-induced parallel autophagic and apoptotic cell death by gypenoside XVII through the estrogen receptor-dependent activation of Nrf2/ARE pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Xiangbao; Wang, Min; Sun, Guibo, E-mail: sunguibo@126.com

Amyloid-beta (Aβ) has a pivotal function in the pathogenesis of Alzheimer's disease. To investigate Aβ neurotoxicity, we used an in vitro model that involves Aβ{sub 25–35}-induced cell death in the nerve growth factor-induced differentiation of PC12 cells. Aβ{sub 25–35} (20 μM) treatment for 24 h caused apoptotic cell death, as evidenced by significant cell viability reduction, LDH release, phosphatidylserine externalization, mitochondrial membrane potential disruption, cytochrome c release, caspase-3 activation, PARP cleavage, and DNA fragmentation in PC12 cells. Aβ{sub 25–35} treatment led to autophagic cell death, as evidenced by augmented GFP-LC3 puncta, conversion of LC3-I to LC3-II, and increased LC3-II/LC3-I ratio.more » Aβ{sub 25–35} treatment induced oxidative stress, as evidenced by intracellular ROS accumulation and increased production of mitochondrial superoxide, malondialdehyde, protein carbonyl, and 8-OHdG. Phytoestrogens have been proved to be protective against Aβ-induced neurotoxicity and regarded as relatively safe targets for AD drug development. Gypenoside XVII (GP-17) is a novel phytoestrogen isolated from Gynostemma pentaphyllum or Panax notoginseng. Pretreatment with GP-17 (10 μM) for 12 h increased estrogen response element reporter activity, activated PI3K/Akt pathways, inhibited GSK-3β, induced Nrf2 nuclear translocation, augmented antioxidant responsive element enhancer activity, upregulated heme oxygenase 1 (HO-1) expression and activity, and provided protective effects against Aβ{sub 25–35}-induced neurotoxicity, including oxidative stress, apoptosis, and autophagic cell death. In conclusion, GP-17 conferred protection against Aβ{sub 25–35}-induced neurotoxicity through estrogen receptor-dependent activation of PI3K/Akt pathways, inactivation of GSK-3β and activation of Nrf2/ARE/HO-1 pathways. This finding might provide novel insights into understanding the mechanism for neuroprotective effects of phytoestrogens or gypenosides. - Highlights: • GP-17 showed protection against Aβ{sub 25–35}-induced neurotoxicity. • The neuroprotective effects of GP-17 are dependent on estrogen receptors. • GP-17 activates Nrf2/ARE/HO-1 pathways. • GP-17 activates PI3K/Akt/GSK-3β pathways.« less

Arachidonic acid induces macrophage cell cycle arrest through the JNK signaling pathway.

PubMed

Shen, Ziying; Ma, Yunqing; Ji, Zhonghao; Hao, Yang; Yan, Xuan; Zhong, Yuan; Tang, Xiaochun; Ren, Wenzhi

2018-02-09

Arachidonic acid (AA) has potent pro-apoptotic effects on cancer cells at a low concentration and on macrophages at a very high concentration. However, the effects of AA on the macrophage cell cycle and related signaling pathways have not been fully investigated. Herein we aim to observe the effect of AA on macrophages cell cycle. AA exposure reduced the viability and number of macrophages in a dose- and time-dependent manner. The reduction in RAW264.7 cell viability was not caused by apoptosis, as indicated by caspase-3 and activated caspase-3 detection. Further research illustrated that AA exposure induced RAW264.7 cell cycle arrested at S phase, and some cell cycle-regulated proteins were altered accordingly. Moreover, JNK signaling was stimulated by AA, and the stimulation was partially reversed by a JNK signaling inhibitor in accordance with cell cycle-related factors. In addition, nuclear and total Foxo1/3a and phosphorylated Foxo1/3a were elevated by AA in a dose- and time-dependent manner, and this elevation was suppressed by the JNK signaling inhibitor. Our study demonstrated that AA inhibits macrophage viability by inducing S phase cell cycle arrest. The JNK signaling pathway and the downstream FoxO transcription factors are involved in AA-induced RAW264.7 cell cycle arrest.

Autocrine prostaglandin E2 signaling promotes promonocytic leukemia cell survival via COX-2 expression and MAPK pathway

PubMed Central

Lee, Jaetae; Lee, Young Sup

2015-01-01

The COX-2/PGE2 pathway has been implicated in the occurrence and progression of cancer. The underlying mechanisms facilitating the production of COX-2 and its mediator, PGE2, in cancer survival remain unknown. Herein, we investigated PGE2-induced COX-2 expression and signaling in HL-60 cells following menadione treatment. Treatment with PGE2 activated anti-apoptotic proteins such as Bcl-2 and Bcl-xL while reducing pro-apoptotic proteins, thereby enhancing cell survival. PGE2 not only induced COX-2 expression, but also prevented casapse-3, PARP, and lamin B cleavage. Silencing and inhibition of COX-2 with siRNA transfection or treatment with indomethacin led to a pronounced reduction of the extracellular levels of PGE2, and restored the menadione-induced cell death. In addition, pretreatment of cells with the MEK inhibitor PD98059 and the PKA inhibitor H89 abrogated the PGE2-induced expression of COX-2, suggesting involvement of the MAPK and PKA pathways. These results demonstrate that PGE2 signaling acts in an autocrine manner, and specific inhibition of PGE2 will provide a novel approach for the treatment of leukemia. [BMB Reports 2015; 48(2): 109-114] PMID:24965577

The Marine Fungal Metabolite, Dicitrinone B, Induces A375 Cell Apoptosis through the ROS-Related Caspase Pathway

PubMed Central

Chen, Li; Gong, Mei-Wei; Peng, Zhen-Fei; Zhou, Tong; Ying, Min-Gang; Zheng, Qiu-Hong; Liu, Qin-Ying; Zhang, Qi-Qing

2014-01-01

Dicitrinone B, a rare carbon-bridged citrinin dimer, was isolated from the marine-derived fungus, Penicillium citrinum. It was reported to have antitumor effects on tumor cells previously; however, the details of the mechanism remain unclear. In this study, we found that dicitrinone B inhibited the proliferation of multiple tumor types. Among them, the human malignant melanoma cell, A375, was confirmed to be the most sensitive. Morphologic evaluation, cell cycle arrest and apoptosis rate analysis results showed that dicitrinone B significantly induced A375 cell apoptosis. Subsequent observation of reactive oxygen species (ROS) accumulation and mitochondrial membrane potential (MMP) reduction revealed that the apoptosis induced by dicitrinone B may be triggered by over-producing ROS. Further studies indicated that the apoptosis was associated with both intrinsic and extrinsic apoptosis pathways under the regulation of Bcl-2 family proteins. Caspase-9, caspase-8 and caspase-3 were activated during the process, leading to PARP cleavage. The pan-caspase inhibitor, Z-VAD-FMK, could reverse dicitrinone B-induced apoptosis, suggesting that it is a caspase-dependent pathway. Our data for the first time showed that dicitrinone B inhibits the proliferation of tumor cells by inducing cell apoptosis. Moreover, compared with the first-line chemotherapy drug, 5-fluorouracil (5-Fu), dicitrinone B showed much more potent anticancer efficacy, suggesting that it might serve as a potential antitumor agent. PMID:24699111

Curcuminoid Binding to Embryonal Carcinoma Cells: Reductive Metabolism, Induction of Apoptosis, Senescence, and Inhibition of Cell Proliferation

PubMed Central

Quitschke, Wolfgang W.

2012-01-01

Curcumin preparations typically contain a mixture of polyphenols, collectively referred to as curcuminoids. In addition to the primary component curcumin, they also contain smaller amounts of the co-extracted derivatives demethoxycurcumin and bisdemethoxycurcumin. Curcuminoids can be differentially solubilized in serum, which allows for the systematic analysis of concentration-dependent cellular binding, biological effects, and metabolism. Technical grade curcumin was solubilized in fetal calf serum by two alternative methods yielding saturated preparations containing either predominantly curcumin (60%) or bisdemethoxycurcumin (55%). Continual exposure of NT2/D1 cells for 4–6 days to either preparation in cell culture media reduced cell division (1–5 µM), induced senescence (6–7 µM) or comprehensive cell death (8–10 µM) in a concentration-dependent manner. Some of these effects could also be elicited in cells transiently exposed to higher concentrations of curcuminoids (47 µM) for 0.5–4 h. Curcuminoids induced apoptosis by generalized activation of caspases but without nucleosomal fragmentation. The equilibrium binding of serum-solubilized curcuminoids to NT2/D1 cells incubated with increasing amounts of curcuminoid-saturated serum occurred with apparent overall dissociation constants in the 6–10 µM range. However, the presence of excess free serum decreased cellular binding in a hyperbolic manner. Cellular binding was overwhelmingly associated with membrane fractions and bound curcuminoids were metabolized in NT2/D1 cells via a previously unidentified reduction pathway. Both the binding affinities for curcuminoids and their reductive metabolic pathways varied in other cell lines. These results suggest that curcuminoids interact with cellular binding sites, thereby activating signal transduction pathways that initiate a variety of biological responses. The dose-dependent effects of these responses further imply that distinct cellular pathways are sequentially activated and that this activation is dependent on the affinity of curcuminoids for the respective binding sites. Defined serum-solubilized curcuminoids used in cell culture media are thus suitable for further investigating the differential activation of signal transduction pathways. PMID:22768090

Competing retention pathways of uranium upon reaction with Fe(II)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massey, Michael S.; Lezama Pacheco, Juan S.; Jones, Morris

Biogeochemical retention processes, including adsorption, reductive precipitation, and incorporation into host minerals, are important in contaminant transport, remediation, and geologic deposition of uranium. Recent work has shown that U can become incorporated into iron (hydr)oxide minerals, with a key pathway arising from Fe(II)-induced transformation of ferrihydrite, (Fe(OH)3•nH2O) to goethite (α-FeO(OH)); this is a possible U retention mechanism in soils and sediments. Several key questions, however, remain unanswered regarding U incorporation into iron (hydr)oxides and this pathway’s contribution to U retention, including: (i) the competitiveness of U incorporation versus reduction to U(IV) and subsequent precipitation of UO2; (ii) the oxidation statemore » of incorporated U; (iii) the effects of uranyl aqueous speciation on U incorporation; and, (iv) the mechanism of U incorporation. Here we use a series of batch reactions conducted at pH ~7, [U(VI)] from 1 to 170 μM, [Fe(II)] from 0 to 3 mM, and [Ca] at 0 or 4 mM) coupled with spectroscopic examination of reaction products of Fe(II)-induced ferrihydrite transformation to address these outstanding questions. Uranium retention pathways were identified and quantified using extended x-ray absorption fine structure (EXAFS) spectroscopy, x-ray powder diffraction, x-ray photoelectron spectroscopy, and transmission electron microscopy. Analysis of EXAFS spectra showed that 14 to 89% of total U was incorporated into goethite, upon reaction with Fe(II) and ferrihydrite. Uranium incorporation was a particularly dominant retention pathway at U concentrations ≤ 50 μM when either uranyl-carbonato or calcium-uranyl-carbonato complexes were dominant, accounting for 64 to 89% of total U. With increasing U(VI) and Fe(II) concentrations, U(VI) reduction to U(IV) became more prevalent, but U incorporation remained a functioning retention pathway. These findings highlight the potential importance of U(V) incorporation within iron oxides as a retention process of U across a wide range of biogeochemical environments and the sensitivity of uranium retention processes to operative (bio)geochemical conditions.« less

Blockade of the ERK pathway enhances the therapeutic efficacy of the histone deacetylase inhibitor MS-275 in human tumor xenograft models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakamoto, Toshiaki; Ozaki, Kei-ichi; Fujio, Kohsuke

2013-04-19

Highlights: •Blockade of the ERK pathway enhances the anticancer efficacy of HDAC inhibitors. •MEK inhibitors sensitize human tumor xenografts to HDAC inhibitor cytotoxicity. •Such the enhanced efficacy is achieved by a transient blockade of the ERK pathway. •This drug combination provides a promising therapeutic strategy for cancer patients. -- Abstract: The ERK pathway is up-regulated in various human cancers and represents a prime target for mechanism-based approaches to cancer treatment. Specific blockade of the ERK pathway alone induces mostly cytostatic rather than pro-apoptotic effects, however, resulting in a limited therapeutic efficacy of the ERK kinase (MEK) inhibitors. We previously showedmore » that MEK inhibitors markedly enhance the ability of histone deacetylase (HDAC) inhibitors to induce apoptosis in tumor cells with constitutive ERK pathway activation in vitro. To evaluate the therapeutic efficacy of such drug combinations, we administered the MEK inhibitor PD184352 or AZD6244 together with the HDAC inhibitor MS-275 in nude mice harboring HT-29 or H1650 xenografts. Co-administration of the MEK inhibitor markedly sensitized the human xenografts to MS-275 cytotoxicity. A dose of MS-275 that alone showed only moderate cytotoxicity thus suppressed the growth of tumor xenografts almost completely as well as induced a marked reduction in tumor cellularity when administered with PD184352 or AZD6244. The combination of the two types of inhibitor also induced marked oxidative stress, which appeared to result in DNA damage and massive cell death, specifically in the tumor xenografts. The enhanced therapeutic efficacy of the drug combination was achieved by a relatively transient blockade of the ERK pathway. Administration of both MEK and HDAC inhibitors represents a promising chemotherapeutic strategy with improved safety for cancer patients.« less

Carcinogenesis and Reactive Oxygen Species Signaling: Interaction of the NADPH Oxidase NOX1-5 and Superoxide Dismutase 1-3 Signal Transduction Pathways.

PubMed

Parascandolo, Alessia; Laukkanen, Mikko O

2018-04-05

Reduction/oxidation (redox) balance could be defined as an even distribution of reduction and oxidation complementary processes and their reaction end products. There is a consensus that aberrant levels of reactive oxygen species (ROS), commonly observed in cancer, stimulate primary cell immortalization and progression of carcinogenesis. However, the mechanism how different ROS regulate redox balance is not completely understood. Recent Advances: In the current review, we have summarized the main signaling cascades inducing NADPH oxidase NOX1-5 and superoxide dismutase (SOD) 1-3 expression and their connection to cell proliferation, immortalization, transformation, and CD34 + cell differentiation in thyroid, colon, lung, breast, and hematological cancers. Interestingly, many of the signaling pathways activating redox enzymes or mediating the effect of ROS are common, such as pathways initiated from G protein-coupled receptors and tyrosine kinase receptors involving protein kinase A, phospholipase C, calcium, and small GTPase signaling molecules. The clarification of interaction of signal transduction pathways could explain how cells regulate redox balance and may even provide means to inhibit the accumulation of harmful levels of ROS in human pathologies. Antioxid. Redox Signal. 00, 000-000.

The Atypical Antipsychotic Agent, Clozapine, Protects Against Corticosterone-Induced Death of PC12 Cells by Regulating the Akt/FoxO3a Signaling Pathway.

PubMed

Zeng, Zhiwen; Wang, Xue; Bhardwaj, Sanjeev K; Zhou, Xuanhe; Little, Peter J; Quirion, Remi; Srivastava, Lalit K; Zheng, Wenhua

2017-07-01

Schizophrenia is one of the most severe psychiatric disorders. Increasing evidence implicates that neurodegeneration is a component of schizophrenia pathology and some atypical antipsychotics are neuroprotective and successful in slowing the progressive morphological brain changes. As an antipsychotic agent, clozapine has superior and unique effects, but the intracellular signaling pathways that mediate clozapine action remain to be elucidated. The phosphatidylinositol-3-kinase/protein kinase B/Forkhead box O3 (PI3K/Akt/FoxO3a) pathway is crucial for neuronal survival. However, little information is available regarding this pathway with clozapine. In the present study, we investigated the protective effect of clozapine on the PC12 cells against corticosterone toxicity. Our results showed that corticosterone decreases the phosphorylation of Akt and FoxO3a, leading to the nuclear localization of FoxO3a and the apoptosis of PC12 cells, while clozapine concentration dependently protected PC12 cells against corticosterone insult. Pathway inhibitors studies displayed that the protective effect of clozapine was reversed by LY294002 and wortmannin, two PI3K inhibitors, or Akt inhibitor VIII although several other inhibitors had no effect. The shRNA knockdown results displayed that downregulated Akt1 or FoxO3a attenuated the protective effect of clozapine. Western blot analyses revealed that clozapine induced the phosphorylation of Akt and FoxO3a by the PI3K/Akt pathway and reversed the reduction of the phosphorylated Akt and FoxO3a and the nuclear translocation of FoxO3a evoked by corticosterone. Together, our data indicates that clozapine protects PC12 cells against corticosterone-induced cell death by modulating activity of the PI3K/Akt/FoxO3a pathway.

Mice lacking the G protein γ3-subunit show resistance to opioids and diet induced obesity

PubMed Central

Schwindinger, William F.; Borrell, Brandon M.; Waldman, Lora C.

2009-01-01

Contributing to the obesity epidemic, there is increasing evidence that overconsumption of high-fat foods may be analogous to drug addiction in that the palatability of these foods is associated with activation of specific reward pathways in the brain. With this perspective, we report that mice lacking the G protein γ3-subunit (Gng3−/− mice) show resistance to high-fat diet-induced weight gain over the course of a 12-wk study. Compared with Gng3+/+ controls, female Gng3−/− mice exhibit a 40% reduction in weight gain and a 53% decrease in fat pad mass, whereas male Gng3−/− mice display an 18% reduction in weight gain and no significant decrease in fat pad mass. The basis for the lowered weight gain is related to reduced food consumption for female and male Gng3−/− mice of 13% and 14%, respectively. Female Gng3−/− mice also show a lesser preference for high-fat chow than their female Gng3+/+ littermates, suggesting an attenuated effect on a reward pathway associated with overconsumption of fat. One possible candidate is the μ-opioid receptor (Oprm1) signaling cascade. Supporting a defect in this signaling pathway, Gng3−/− mice show marked reductions in both acute and chronic morphine responsiveness, as well as increases in endogenous opioid mRNA levels in reward-related regions of the brain. Taken together, these data suggest that the decreased weight gain of Gng3−/− mice may be related to a reduced rewarding effect of the high-fat diet resulting from a defect in Oprm1 signaling and loss of the G protein γ3-subunit. PMID:19759336

Novel orally active epoxyeicosatrienoic acid (EET) analogs attenuate cisplatin nephrotoxicity

PubMed Central

Khan, Md. Abdul Hye; Liu, Jing; Kumar, Ganesh; Skapek, Stephen X.; Falck, John R.; Imig, John D.

2013-01-01

Nephrotoxicity severely limits the use of the anticancer drug cisplatin. Oxidative stress, inflammation, and endoplasmic reticulum (ER) stress contribute to cisplatin-induced nephrotoxicity. We developed novel orally active epoxyeicosatrienoic acid (EET) analogs and investigated their prophylactic effect in cisplatin-induced nephrotoxicity in rats. Cisplatin-induced nephrotoxicity was manifested by increases in blood urea nitrogen, plasma creatinine, urinary N-acetyl-β-(d)-glucosaminidase activity, kidney injury molecule 1, and histopathology. EET analogs (10 mg/kg/d) attenuated cisplatin-induced nephrotoxicity by reducing these renal injury markers by 40–80% along with a 50–70% reduction in renal tubular cast formation. This attenuated renal injury is associated with reduced oxidative stress, inflammation, and ER stress evident from reduction in related biomarkers and in the renal expression of genes involved in these pathways. Moreover, we demonstrated that the attenuated nephrotoxicity correlated with decreased apoptosis that is associated with 50–90% reduction in Bcl-2 protein family mediated proapoptotic signaling, reduced renal caspase-12 expression, and a 50% reduction in renal caspase-3 activity. We further demonstrated in vitro that the protective activity of EET analogs does not compromise the anticancer effects of cisplatin. Collectively, our data provide evidence that EET analogs attenuate cisplatin-induced nephrotoxicity by reducing oxidative stress, inflammation, ER stress, and apoptosis without affecting the chemotherapeutic effects of cisplatin.—Khan, Md. A. H., Liu, J., Kumar, G., Skapek, S. X., Falck, J. R., Imig, J. D. Novel orally active epoxyeicosatrienoic acid (EET) analogs attenuate cisplatin nephrotoxicity. PMID:23603837

Direct observation of ultrafast-electron-transfer reactions unravels high effectiveness of reductive DNA damage

PubMed Central

Nguyen, Jenny; Ma, Yuhan; Luo, Ting; Bristow, Robert G.; Jaffray, David A.; Lu, Qing-Bin

2011-01-01

Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosecond time-resolved laser spectroscopy measurements of ultrafast-electron-transfer (UET) reactions of with various scavengers (KNO3, isopropanol, and dimethyl sulfoxide) and the first gel electrophoresis measurements of DNA strand breaks induced by and OH• radicals co-produced by two-UV-photon photolysis of water. We strikingly found that the yield of reductive DNA strand breaks induced by each is twice the yield of oxidative DNA strand breaks induced by each OH• radical. Our results not only unravel the long-standing mystery about the relative role of radicals in inducing DNA damage under ionizing radiation, but also challenge the conventional notion that oxidative damage is the main pathway for DNA damage. The results also show the potential of femtomedicine as a new transdisciplinary frontier and the broad significance of UET reactions of in many processes in chemistry, physics, biology, and the environment. PMID:21730183

Nitric oxide-releasing sulindac is a novel skin cancer chemopreventive agent for UVB-induced photocarcinogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaudhary, Sandeep C.; Singh, Tripti; Kapur, Puneet

Nitric oxide (NO)-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) which have been synthesized to reduce gastro-intestinal and cardiovascular toxicities of NSAIDs, possess anti-proliferative, pro-apoptotic and anti-cancer activities. Here, we show that NO-sulindac inhibited UVB-induced skin tumorigenesis in SKH-1 hairless mice. Topical application of NO-sulindac reduced tumor incidence, number (p < 0.05) and volume (p < 0.005) as compared to UVB (alone)-irradiated vehicle-treated mice. An increase in TUNEL-positive cells in skin lesions was accompanied by the enhanced Bax:Bcl-2 ratio. The expression of pro-apoptotic Bax was increased whereas anti-apoptotic Bcl-2 reduced. However, proliferation was identified as the major target of NO-sulindac in this study.more » A reduced expression of PCNA and cyclin D1 associated with the dampening of cell cycle progression was observed. The mechanism of this inhibition was related to the reduction in UVB-induced Notch signaling pathway. UVB-induced inflammatory responses were diminished by NO-sulindac as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases Erk1/2, p38 and JNK1/2. In this regard, NO-sulindac also inhibited NFκB by enhancing IκBα as evidenced by the reduced expression of iNOS and COX-2, the direct NFκB transcription target proteins. NO-sulindac significantly diminished the progression of benign lesions to invasive carcinomas by suppressing the tumor aggressiveness and retarding epithelial–mesenchymal transition. A marked decrease in the expression of mesenchymal markers such as Fibronectin, N-cadherin, SNAI, Slug and Twist and an increase in epithelial cell polarity marker E-cadherin were noted in NO-sulindac-treated tumors. Our data suggest that NO-sulindac is a potent inhibitor of UVB-induced skin carcinogenesis and acts by targeting proliferation-regulatory pathways. - Highlights: ► NO-sulindac is a potent chemopreventive agent for UVB-induced skin cancer. ► NO-sulindac effectively blocks proliferation. ► NO-sulindac targets Notch and RXR-PI3k/Akt pathway to achieve anti-tumor efficacy.« less

Kit signaling inhibits the sphingomyelin-ceramide pathway through PLC gamma 1: implication in stem cell factor radioprotective effect.

PubMed

Maddens, Stéphane; Charruyer, Alexandra; Plo, Isabelle; Dubreuil, Patrice; Berger, Stuart; Salles, Bernard; Laurent, Guy; Jaffrézou, Jean-Pierre

2002-08-15

Previous studies demonstrated that Kit activation confers radioprotection. However, the mechanism by which Kit signaling interferes with cellular response to ionizing radiation (IR) has not been firmly established. Based on the role of the sphingomyelin (SM) cycle apoptotic pathway in IR-induced apoptosis, we hypothesized that one of the Kit signaling components might inhibit IR-induced ceramide production or ceramide-induced apoptosis. Results show that, in both Ba/F3 and 32D murine cell lines transfected with wild-type c-kit, stem cell factor (SCF) stimulation resulted in a significant reduction of IR-induced apoptosis and cytotoxicity, whereas DNA repair remained unaffected. Moreover, SCF stimulation inhibited IR-induced neutral sphingomyelinase (N-SMase) stimulation and ceramide production. The SCF inhibitory effect on SM cycle was not influenced by wortmannin, a phosphoinositide-3 kinase (PI3K) inhibitor. The SCF protective effect was maintained in 32D-KitYF719 cells in which the PI3K/Akt signaling pathway is abolished due to mutation in Kit docking site for PI3K. In contrast, phospholipase C gamma (PLC gamma) inhibition by U73122 totally restored IR-induced N-SMase stimulation, ceramide production, and apoptosis in Kit-activated cells. Moreover, SCF did not protect 32D-KitYF728 cells (lacking a functional docking site for PLC gamma 1), from IR-induced SM cycle. Finally, SCF-induced radioprotection of human CD34(+) bone marrow cells was also inhibited by U73122. Altogether, these results suggest that SCF radioprotection is due to PLC gamma 1-dependent negative regulation of IR-induced N-SMase stimulation. Beyond the scope of Kit-expressing cells, it suggests that PLC gamma 1 status could greatly influence the post-DNA damage cellular response to IR, and perhaps, to other genotoxic agents.

N-(2-Hydroxyphenyl)acetamide: a Novel Suppressor of RANK/RANKL Pathway in Collagen-Induced Arthritis Model in Rats.

PubMed

Gul, Anum; Kunwar, Bimal; Mazhar, Maryam; Perveen, Kahkashan; Simjee, Shabana U

2017-08-01

RANKL and RANK are potential contributors of inflammatory cascade in human and animal model of arthritis. The current study aims to investigate the effect of N-(2-hydroxyphenyl)acetamide (NA-2) on regulation of RANKL pathway in collagen-induced arthritis (CIA) model in rats. CIA was induced using bovine type II collagen in female Wistar rats. The clinical parameters, level of pro-inflammatory and oxidative stress markers were measured to determine the progression of the disease. The mRNA level of RANKL and RANK and downstream mediators of inflammation i.e. c-fos, c-jun, NF-κB and Akt were analysed in spleen tissue using real-time PCR. Immunohistochemical analysis of iNOS, pAkt and c-Fos was also done in spleen tissue. Treatment with NA-2 and indomethacin showed increase in body weight and significant reduction in paw volume and arthritic score (p < 0.0001). Marked reduction in the level of oxidative stress markers, NO, PO and GSH (p < 0.0001), and pro-inflammatory markers, IL-1β (p < 0.0001) and TNF-α (p < 0.01), was also observed. Likewise, NA-2 and indomethacin treatment also significantly suppressed the mRNA expression of RANKL, RANK, c-fos, c-jun, NF-κB (p < 0.0001) and Akt (p < 0.01) and protein expression of iNOS, pAkt and c-Fos (p < 0.0001) compared to the arthritic control group. Our findings suggest that NA-2 is an antiarthritic agent acting in a pleiotropic manner in CIA rats by not only reducing the clinical signs of arthritis, inflammatory cytokines and free radical production but also attenuating the RANK/RANKL signaling pathway.

Proteome-based systems biology analysis of the diabetic mouse aorta reveals major changes in fatty acid biosynthesis as potential hallmark in diabetes mellitus-associated vascular disease.

PubMed

Husi, Holger; Van Agtmael, Tom; Mullen, William; Bahlmann, Ferdinand H; Schanstra, Joost P; Vlahou, Antonia; Delles, Christian; Perco, Paul; Mischak, Harald

2014-04-01

Macrovascular complications of diabetes mellitus are a major risk factor for cardiovascular morbidity and mortality. Currently, studies only partially described the molecular pathophysiology of diabetes mellitus-associated effects on vasculature. However, better understanding of systemic effects is essential in unraveling key molecular events in the vascular tissue responsible for disease onset and progression. Our overall aim was to get an all-encompassing view of diabetes mellitus-induced key molecular changes in the vasculature. An integrative proteomic and bioinformatics analysis of data from aortic vessels in the low-dose streptozotocin-induced diabetic mouse model (10 animals) was performed. We observed pronounced dysregulation of molecules involved in myogenesis, vascularization, hypertension, hypertrophy (associated with thickening of the aortic wall), and a substantial reduction of fatty acid storage. A novel finding is the pronounced downregulation of glycogen synthase kinase-3β (Gsk3β) and upregulation of molecules linked to the tricarboxylic acid cycle (eg, aspartate aminotransferase [Got2] and hydroxyacid-oxoacid transhydrogenase [Adhfe1]). In addition, pathways involving primary alcohols and amino acid breakdown are altered, potentially leading to ketone-body production. A number of these findings were validated immunohistochemically. Collectively, the data support the hypothesis that in this diabetic model, there is an overproduction of ketone-bodies within the vessels using an alternative tricarboxylic acid cycle-associated pathway, ultimately leading to the development of atherosclerosis. Streptozotocin-induced diabetes mellitus in animals leads to a reduction of fatty acid biosynthesis and an upregulation of an alternative ketone-body formation pathway. This working hypothesis could form the basis for the development of novel therapeutic intervention and disease management approaches.

Tanshinone IIA protects H9c2 cells from oxidative stress-induced cell death via microRNA-133 upregulation and Akt activation.

PubMed

Gu, Yunfei; Liang, Zhuo; Wang, Haijun; Jin, Jun; Zhang, Shouyan; Xue, Shufeng; Chen, Jianfeng; He, Huijuan; Duan, Kadan; Wang, Jing; Chang, Xuewei; Qiu, Chunguang

2016-08-01

The aim of the present study was to investigate the cardioprotective effect of tanshinone IIA and the underlying molecular mechanisms. An in vitro model of oxidative stress injury was established in cardiac H9c2 cells, and the effects of tanshinone IIa were investigated using cell viability, reverse transcription-quantitative polymerase chain reaction and western blotting assays. The results demonstrated that tanshinone IIA protects H9c2 cells from H 2 O 2 -induced cell death in a concentration-dependent manner, via a mechanism involving microRNA-133 (miR-133), and that treatment with TIIA alone exerted no cytotoxic effects on H9c2. In order to further elucidate the mechanisms underlying the actions of TIIA, reverse transcription-quantitative polymease chain reaction and western blot analysis were performed. Reductions in miR-133 expression levels induced by increasing concentrations of H 2 O 2 were reversed by treatment with tanshinone IIA. In addition, the inhibition of miR-133 by transfection with an miR-133 inhibitor abolished the cardioprotective effects of tanshinone IIA against H 2 O 2 -induced cell death. Furthermore, western blot analysis demonstrated that tanshinone IIA activated Akt kinase via the phosphorylation of serine 473. Inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway by pretreatment with the PI3K specific inhibitors wortmannin and LY294002 also eliminated the cardioprotective effects of tanshinone IIA against H 2 O 2 -induced cell death. Western blot analysis demonstrated that H 2 O 2 -induced reductions in B cell lymphoma 2 (Bcl-2) expression levels were reversed by tanshinone IIA. In addition, the effect of tanshinone IIA on Bcl-2 protein expression level in an oxidative environment was suppressed by a PI3K inhibitor, wortmannin, indicating that tanshinone IIA exerts cardioprotective effects against H 2 O 2 -induced cell death via the activation of the PI3K/Akt signal transduction pathway and the consequent upregulation of Bcl-2. In conclusion, the present study demonstrates that TIIA is able to protcet H9c2 cells from oxidative stress-induced cell death through signalling pathways involving miR-133 and Akt, and that tanshinone IIA is a promising natural cardioprotective agent.

Interleukin-1β: A New Regulator of the Kynurenine Pathway Affecting Human Hippocampal Neurogenesis

PubMed Central

Zunszain, Patricia A; Anacker, Christoph; Cattaneo, Annamaria; Choudhury, Shanas; Musaelyan, Ksenia; Myint, Aye Mu; Thuret, Sandrine; Price, Jack; Pariante, Carmine M

2012-01-01

Increased inflammation and reduced neurogenesis have been associated with the pathophysiology of major depression. Here, we show for the first time how IL-1β, a pro-inflammatory cytokine shown to be increased in depressed patients, decreases neurogenesis in human hippocampal progenitor cells. IL-1β was detrimental to neurogenesis, as shown by a decrease in the number of doublecortin-positive neuroblasts (−28%), and mature, microtubule-associated protein-2-positive neurons (−36%). Analysis of the enzymes that regulate the kynurenine pathway showed that IL-1β induced an upregulation of transcripts for indolamine-2,3-dioxygenase (IDO), kynurenine 3-monooxygenase (KMO), and kynureninase (42-, 12- and 30-fold increase, respectively, under differentiating conditions), the enzymes involved in the neurotoxic arm of the kynurenine pathway. Moreover, treatment with IL-1β resulted in an increase in kynurenine, the catabolic product of IDO-induced tryptophan metabolism. Interestingly, co-treatment with the KMO inhibitor Ro 61-8048 reversed the detrimental effects of IL-1β on neurogenesis. These observations indicate that IL-1β has a critical role in regulating neurogenesis whereas affecting the availability of tryptophan and the production of enzymes conducive to toxic metabolites. Our results suggest that inhibition of the kynurenine pathway may provide a new therapy to revert inflammatory-induced reduction in neurogenesis. PMID:22071871

SMAD signaling drives heart and muscle dysfunction in a Drosophila model of muscular dystrophy.

PubMed

Goldstein, Jeffery A; Kelly, Sean M; LoPresti, Peter P; Heydemann, Ahlke; Earley, Judy U; Ferguson, Edwin L; Wolf, Matthew J; McNally, Elizabeth M

2011-03-01

Loss-of-function mutations in the genes encoding dystrophin and the associated membrane proteins, the sarcoglycans, produce muscular dystrophy and cardiomyopathy. The dystrophin complex provides stability to the plasma membrane of striated muscle during muscle contraction. Increased SMAD signaling due to activation of the transforming growth factor-β (TGFβ) pathway has been described in muscular dystrophy; however, it is not known whether this canonical TGFβ signaling is pathogenic in the muscle itself. Drosophila deleted for the γ/δ-sarcoglycan gene (Sgcd) develop progressive muscle and heart dysfunction and serve as a model for the human disorder. We used dad-lacZ flies to demonstrate the signature of TGFβ activation in response to exercise-induced injury in Sgcd null flies, finding that those muscle nuclei immediately adjacent to muscle injury demonstrate high-level TGFβ signaling. To determine the pathogenic nature of this signaling, we found that partial reduction of the co-SMAD Medea, homologous to SMAD4, or the r-SMAD, Smox, corrected both heart and muscle dysfunction in Sgcd mutants. Reduction in the r-SMAD, MAD, restored muscle function but interestingly not heart function in Sgcd mutants, consistent with a role for activin but not bone morphogenic protein signaling in cardiac dysfunction. Mammalian sarcoglycan null muscle was also found to exhibit exercise-induced SMAD signaling. These data demonstrate that hyperactivation of SMAD signaling occurs in response to repetitive injury in muscle and heart. Reduction of this pathway is sufficient to restore cardiac and muscle function and is therefore a target for therapeutic reduction.

SMAD signaling drives heart and muscle dysfunction in a Drosophila model of muscular dystrophy

PubMed Central

Goldstein, Jeffery A.; Kelly, Sean M.; LoPresti, Peter P.; Heydemann, Ahlke; Earley, Judy U.; Ferguson, Edwin L.; Wolf, Matthew J.; McNally, Elizabeth M.

2011-01-01

Loss-of-function mutations in the genes encoding dystrophin and the associated membrane proteins, the sarcoglycans, produce muscular dystrophy and cardiomyopathy. The dystrophin complex provides stability to the plasma membrane of striated muscle during muscle contraction. Increased SMAD signaling due to activation of the transforming growth factor-β (TGFβ) pathway has been described in muscular dystrophy; however, it is not known whether this canonical TGFβ signaling is pathogenic in the muscle itself. Drosophila deleted for the γ/δ-sarcoglycan gene (Sgcd) develop progressive muscle and heart dysfunction and serve as a model for the human disorder. We used dad-lacZ flies to demonstrate the signature of TGFβ activation in response to exercise-induced injury in Sgcd null flies, finding that those muscle nuclei immediately adjacent to muscle injury demonstrate high-level TGFβ signaling. To determine the pathogenic nature of this signaling, we found that partial reduction of the co-SMAD Medea, homologous to SMAD4, or the r-SMAD, Smox, corrected both heart and muscle dysfunction in Sgcd mutants. Reduction in the r-SMAD, MAD, restored muscle function but interestingly not heart function in Sgcd mutants, consistent with a role for activin but not bone morphogenic protein signaling in cardiac dysfunction. Mammalian sarcoglycan null muscle was also found to exhibit exercise-induced SMAD signaling. These data demonstrate that hyperactivation of SMAD signaling occurs in response to repetitive injury in muscle and heart. Reduction of this pathway is sufficient to restore cardiac and muscle function and is therefore a target for therapeutic reduction. PMID:21138941

Zanthoxylum ailanthoides Suppresses Oleic Acid-Induced Lipid Accumulation through an Activation of LKB1/AMPK Pathway in HepG2 Cells

PubMed Central

Kwon, Eun-Bin; Kang, Myung-Ji; Kim, Soo-Yeon; Lee, Yong-Moon; Lee, Mi-Kyeong; Yuk, Heung Joo; Ryu, Hyung Won; Lee, Su Ui

2018-01-01

Zanthoxylum ailanthoides (ZA) has been used as folk medicines in East Asian and recently reported to have several bioactivity; however, the studies of ZA on the regulation of triacylglycerol (TG) biosynthesis have not been elucidated yet. In this study, we examined whether the methanol extract of ZA (ZA-M) could reduce oleic acid- (OA-) induced intracellular lipid accumulation and confirmed its mode of action in HepG2 cells. ZA-M was shown to promote the phosphorylation of AMPK and its upstream LKB1, followed by reduction of lipogenic gene expressions. As a result, treatment of ZA-M blocked de novo TG biosynthesis and subsequently mitigated intracellular neutral lipid accumulation in HepG2 cells. ZA-M also inhibited OA-induced production of reactive oxygen species (ROS) and TNF-α, suggesting that ZA-M possess the anti-inflammatory feature in fatty acid over accumulated condition. Taken together, these results suggest that ZA-M attenuates OA-induced lipid accumulation and inflammation through the activation of LKB1/AMPK signaling pathway in HepG2 cells. PMID:29507591

Zanthoxylum ailanthoides Suppresses Oleic Acid-Induced Lipid Accumulation through an Activation of LKB1/AMPK Pathway in HepG2 Cells.

PubMed

Kwon, Eun-Bin; Kang, Myung-Ji; Kim, Soo-Yeon; Lee, Yong-Moon; Lee, Mi-Kyeong; Yuk, Heung Joo; Ryu, Hyung Won; Lee, Su Ui; Oh, Sei-Ryang; Moon, Dong-Oh; Lee, Hyun-Sun; Kim, Mun-Ock

2018-01-01

Zanthoxylum ailanthoides (ZA) has been used as folk medicines in East Asian and recently reported to have several bioactivity; however, the studies of ZA on the regulation of triacylglycerol (TG) biosynthesis have not been elucidated yet. In this study, we examined whether the methanol extract of ZA (ZA-M) could reduce oleic acid- (OA-) induced intracellular lipid accumulation and confirmed its mode of action in HepG2 cells. ZA-M was shown to promote the phosphorylation of AMPK and its upstream LKB1, followed by reduction of lipogenic gene expressions. As a result, treatment of ZA-M blocked de novo TG biosynthesis and subsequently mitigated intracellular neutral lipid accumulation in HepG2 cells. ZA-M also inhibited OA-induced production of reactive oxygen species (ROS) and TNF- α , suggesting that ZA-M possess the anti-inflammatory feature in fatty acid over accumulated condition. Taken together, these results suggest that ZA-M attenuates OA-induced lipid accumulation and inflammation through the activation of LKB1/AMPK signaling pathway in HepG2 cells.

Pomegranate protects liver against cecal ligation and puncture-induced oxidative stress and inflammation in rats through TLR4/NF-κB pathway inhibition.

PubMed

Makled, Mirhan N; El-Awady, Mohammed S; Abdelaziz, Rania R; Atwan, Nadia; Guns, Emma T; Gameil, Nariman M; Shehab El-Din, Ahmed B; Ammar, Elsayed M

2016-04-01

Acute liver injury secondary to sepsis is a major challenge in intensive care unit. This study was designed to investigate potential protective effects of pomegranate against sepsis-induced acute liver injury in rats and possible underlying mechanisms. Pomegranate was orally given (800mg/kg/day) for two weeks before sepsis induction by cecal ligation and puncture (CLP). Pomegranate improved survival and attenuated liver inflammatory response, likely related to downregulation of mRNA expression of toll like recptor-4, reduced nuclear translocation and DNA binding activity of proinflammatory transcription factor NF-κB subunit p65, decreased mRNA and protein expression of tumor necrosis factor-alpha and reduction in myeloperoxidase activity and mRNA expression. Pomegranate also decreased CLP-induced oxidative stress as reflected by decreased malondialdehyde content, and increased reduced glutathione level and superoxide dismutase activity. These results confirm the antiinflammatory and antioxidant effects of pomegranate in CLP-induced acute liver injury mediated through inhibiting TLR4/NF-κB pathway, lipid peroxidation and neutrophil infiltration. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanistic exploration of a bi-directional PDT-based combination in pancreatic cancer (Conference Presentation)

NASA Astrophysics Data System (ADS)

Huang, Huang-Chiao; Mallidi, Srivalleesha; Liu, Joyce; Chiang, Chun-Te; Mai, Zhiming; Goldschmidt, Ruth; Rizvi, Imran; Ebrahim-Zadeh, Neema; Hasan, Tayyaba

2016-03-01

It is increasingly evident that the most effective cancer treatments will involve interactive regimens that target multiple non-overlapping pathways, preferably such that each component enhances the others to improve outcomes while minimizing systemic toxicities. Toward this goal, we developed a combination of photodynamic therapy and irinotecan, which mechanistically cooperate with each other, beyond their individual tumor destruction pathways, to cause synergistic reduction in orthotopic pancreatic tumor burden. A three-way mechanistic basis of the observed the synergism will be discussed: (i) PDT downregulates drug efflux transporters to increase intracellular irinotecan levels. (ii) Irinotecan reduces the expression of hypoxia-induced marker, which is upregulated by PDT. (iii) PDT downregulates irinotecan-induced survivin expression to amplify the apoptotic and anti-proliferative effects. The clinical translation potential of the combination will also be highlighted.

TRPC3 channels play a critical role in the theta component of pilocarpine-induced Status Epilepticus in mice

PubMed Central

Phelan, Kevin D.; Shwe, U Thaung; Cozart, Michael A.; Wu, Hong; Mock, Matthew M.; Abramowitz, Joel; Birnbaumer, Lutz; Zheng, Fang

2016-01-01

Summary Objective Canonical transient receptor potential (TRPC) channels constitute a family of cation channels that exhibit a regional and cell-specific expression pattern throughout the brain. It has been reported previously that TRPC3 channels are effectors of the BDNF/trkB signaling pathway. Given the long postulated role of BDNF in epileptogenesis, TRPC3 channels may be a critical component in the underlying pathophysiology of seizure and epilepsy. In this study, we investigated the precise role of TRPC3 channels in pilocarpine-induced Status Epilepticus (SE). Methods The role of TRPC3 channels was investigated using TRPC3 knockout (KO) mice and TRPC3-selective inhibitor Pyr3. Video and EEG recording of pilocarpine-induced seizures were performed. Results We found that genetic ablation of TRPC3 channels reduces behavioral manifestations of seizures and the root-mean-square (RMS) power of SE, indicating a significant contribution of TRPC3 channels to pilocarpine-induced SE. Furthermore, the reduction in SE in TRPC3KO mice is caused by a selective attenuation of pilocarpine-induced theta activity which dominates both the pre-ictal phase and SE phase. Pyr3 also caused a reduction in the overall RMS power of pilocarpine-induced SE and a selective reduction in the theta activity during SE. Significance Our results demonstrate that TRPC3 channels unequivocally contribute to pilocarpine-induced SE and could be a novel molecular target for new anti-convulsive drugs. PMID:28012173

Iron(II) porphyrins induced conversion of nitrite into nitric oxide: A computational study.

PubMed

Zhang, Ting Ting; Liu, Yong Dong; Zhong, Ru Gang

2015-09-01

Nitrite reduction to nitric oxide by heme proteins was reported as a protective mechanism to hypoxic injury in mammalian physiology. In this study, the pathways of nitrite reduction to nitric oxide mediated by iron(II) porphyrin (P) complexes, which were generally recognized as models for heme proteins, were investigated by using density functional theory (DFT). In view of two type isomers of combination of nitrite and Fe(II)(P), N-nitro- and O-nitrito-Fe(II)-porphyrin complexes, and two binding sites of proton to the different O atoms of nitrite moiety, four main pathways for the conversion of nitrite into nitric oxide mediated by iron(II) porphyrins were proposed. The results indicate that the pathway of N-bound Fe(II)(P)(NO2) isomer into Fe(III)(P)(NO) and water is similar to that of O-bound isomer into nitric oxide and Fe(III)(P)(OH) in both thermodynamical and dynamical aspects. Based on the initial computational studies of five-coordinate nitrite complexes, the conversion of nitrite into NO mediated by Fe(II)(P)(L) complexes with 14 kinds of proximal ligands was also investigated. Generally, the same conclusion that the pathways of N-bound isomers are similar to those of O-bound isomer was obtained for iron(II) porphyrin with ligands. Different effects of ligands on the reduction reactions were also found. It is notable that the negative proximal ligands can improve reactive abilities of N-nitro-iron(II) porphyrins in the conversion of nitrite into nitric oxide compared to neutral ligands. The findings will be helpful to expand our understanding of the mechanism of nitrite reduction to nitric oxide by iron(II) porphyrins. Copyright © 2015 Elsevier Inc. All rights reserved.

Green Tea Polyphenols Attenuated Glutamate Excitotoxicity via Antioxidative and Antiapoptotic Pathway in the Primary Cultured Cortical Neurons.

PubMed

Cong, Lin; Cao, Chang; Cheng, Yong; Qin, Xiao-Yan

2016-01-01

Green tea polyphenols are a natural product which has antioxidative and antiapoptotic effects. It has been shown that glutamate excitotoxicity induced oxidative stress is linked to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. In this study we explored the neuroprotective effect of green teen polyphenols against glutamate excitotoxicity in the primary cultured cortical neurons. We found that green tea polyphenols protected against glutamate induced neurotoxicity in the cortical neurons as measured by MTT and TUNEL assays. Green tea polyphenols were then showed to inhibit the glutamate induced ROS release and SOD activity reduction in the neurons. Furthermore, our results demonstrated that green tea polyphenols restored the dysfunction of mitochondrial pro- or antiapoptotic proteins Bax, Bcl-2, and caspase-3 caused by glutamate. Interestingly, the neuroprotective effect of green tea polyphenols was abrogated when the neurons were incubated with siBcl-2. Taken together, these results demonstrated that green tea polyphenols protected against glutamate excitotoxicity through antioxidative and antiapoptotic pathways.

Design and Synthesis of Novel Small-molecule Inhibitors of the Hypoxia Inducible Factor Pathway

PubMed Central

Mooring, Suazette Reid; Jin, Hui; Devi, Narra S.; Jabbar, Adnan A.; Kaluz, Stefan; Liu, Yuan; Van Meir, Erwin G.; Wang, Binghe

2012-01-01

Hypoxia, a reduction in partial oxygen pressure, is a salient property of solid tumors. Hypoxia drives malignant progression and metastasis in tumors and participates in tumor resistance to radio- and chemotherapies. Hypoxia activates the hypoxia-inducible factor (HIF) family of transcription factors, which induce target genes that regulate adaptive biological processes such as anaerobic metabolism, cell motility and angiogenesis. Clinical evidence has demonstrated that expression of HIF-1 is strongly associated with poor patient prognosis and activation of HIF-1 contributes to malignant behavior and therapeutic resistance. Consequently, HIF-1 has become an important therapeutic target for inhibition by small molecules. Herein, we describe the design and synthesis of small molecules that inhibit the HIF-1 signaling pathway. Many of these compounds exhibit inhibitory activity in the nanomolar range. Separate mechanistic studies indicate that these inhibitors do not alter HIF-1 levels, but interfere with the HIF-1α/HIF-1β/p300/CBP complex formation by interacting with p300 and CBP. PMID:22032632

Eckol protects V79-4 lung fibroblast cells against gamma-ray radiation-induced apoptosis via the scavenging of reactive oxygen species and inhibiting of the c-Jun NH(2)-terminal kinase pathway.

PubMed

Zhang, Rui; Kang, Kyoung Ah; Piao, Mei Jing; Ko, Dong Ok; Wang, Zhi Hong; Lee, In Kyung; Kim, Bum Joon; Jeong, Il Yun; Shin, Taekyun; Park, Jae Woo; Lee, Nam Ho; Hyun, Jin Won

2008-09-04

The radioprotective effect of eckol against gamma-ray radiation-induced oxidative stress and its possible protective mechanisms were investigated. Eckol was found to reduce the intracellular reactive oxygen species generated by gamma-ray radiation. Moreover, eckol also protected against radiation-induced cellular DNA damage and membrane lipid peroxidation, which are the main targets of radiation-induced damage. In addition, eckol recovered the cell viability damaged by radiation via the inhibition of apoptosis. Irradiated cells with eckol treatment reduced the expression of bax, the activation of caspase 9 and caspase 3, which were induced by radiation. However, irradiated cells with eckol recovered the expression of bcl-2 and mitochondrial cytochrome c which were decreased by radiation. The anti-apoptotic effect of eckol exerted via the inhibition of mitogen-activated protein kinase kinase-4 (MKK4/SEK1)-c-Jun NH(2)-terminal kinase (JNK)-activator protein 1 (AP-1) cascades induced by radiation. In summary, the results suggest that eckol protects cells against the oxidative stress induced by radiation via the reduction of reactive oxygen species and the attenuation of activation in SEK1-JNK-AP-1 pathway.

α-Lipoic acid protects against the cytotoxicity and oxidative stress induced by cadmium in HepG2 cells through regeneration of glutathione by glutathione reductase via Nrf2/ARE signaling pathway.

PubMed

Shi, Chunli; Zhou, Xue; Zhang, Jiayu; Wang, Jiachun; Xie, Hong; Wu, Zhigang

2016-07-01

α-Lipoic acid (α-LA) is a potent natural antioxidant, which is capable of regenerating glutathione (GSH). However, the mechanisms by which α-LA regenerates reduced glutathione (rGSH) via the reduction of oxidized glutathione (GSSG) by glutathione reductase (GR) are still not well understood. In the present study, we investigated if α-LA replenished rGSH by GR via Nrf2/ARE signaling pathway in cadmium-treated HepG2 cells. We found that α-LA antagonized the oxidative damage and alleviated the cytotoxicity in cadmium-induced HepG2 cells by regeneration of rGSH. α-LA regenerated rGSH by activating Nrf2 signaling pathway via promoting the nuclear translocation of Nrf2, which upregulates the transcription of GR, and thus increased the activity of GR. Our results indicated that α-LA was an effective agent to antagonize the oxidative stress and alleviate the cytotoxicity in cadmium-treated HepG2 cells by regenerating rGSH through activating Nrf2 signaling pathway. Copyright © 2016. Published by Elsevier B.V.

Mutant Copper-Zinc Superoxide Dismutase (SOD1) Induces Protein Secretion Pathway Alterations and Exosome Release in Astrocytes

PubMed Central

Basso, Manuela; Pozzi, Silvia; Tortarolo, Massimo; Fiordaliso, Fabio; Bisighini, Cinzia; Pasetto, Laura; Spaltro, Gabriella; Lidonnici, Dario; Gensano, Francesco; Battaglia, Elisa; Bendotti, Caterina; Bonetto, Valentina

2013-01-01

Amyotrophic lateral sclerosis is the most common motor neuron disease and is still incurable. The mechanisms leading to the selective motor neuron vulnerability are still not known. The interplay between motor neurons and astrocytes is crucial in the outcome of the disease. We show that mutant copper-zinc superoxide dismutase (SOD1) overexpression in primary astrocyte cultures is associated with decreased levels of proteins involved in secretory pathways. This is linked to a general reduction of total secreted proteins, except for specific enrichment in a number of proteins in the media, such as mutant SOD1 and valosin-containing protein (VCP)/p97. Because there was also an increase in exosome release, we can deduce that astrocytes expressing mutant SOD1 activate unconventional secretory pathways, possibly as a protective mechanism. This may help limit the formation of intracellular aggregates and overcome mutant SOD1 toxicity. We also found that astrocyte-derived exosomes efficiently transfer mutant SOD1 to spinal neurons and induce selective motor neuron death. We conclude that the expression of mutant SOD1 has a substantial impact on astrocyte protein secretion pathways, contributing to motor neuron pathology and disease spread. PMID:23592792

Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists.

PubMed

Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-08-22

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5'AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII's effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions.

PubMed

Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo

2016-02-05

As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ginkgo biloba L. attenuates spontaneous recurrent seizures and associated neurological conditions in lithium-pilocarpine rat model of temporal lobe epilepsy through inhibition of mammalian target of rapamycin pathway hyperactivation.

PubMed

Mazumder, Arindam Ghosh; Sharma, Pallavi; Patial, Vikram; Singh, Damanpreet

2017-05-23

Ginkgo biloba L. (Ginkgoaceae) has been widely used in traditional medicine for variety of neurological conditions particularly behavioral and memory impairments. The present study was envisaged to explore the effect of a standardized fraction of Ginkgo biloba leaves (GBbf) in rat model of lithium-pilocarpine induced spontaneous recurrent seizures, and associated behavioral impairments and cognitive deficit. Rats showing appearance of spontaneous recurrent seizures following lithium pilocarpine (LiPc)-induced status epilepticus (SE) were treated with different doses of GBbf or vehicle for subsequent 4 weeks. The severity of seizures and aggression in rats were scored following treatment with GBbf. Further, open field, forced swim, novel object recognition and Morris water maze tests were conducted. Histopathological, protein levels and gene expression studies were performed in the isolated brains. Treatment with GBbf reduced seizure severity score and aggression in epileptic animals. Improved spatial cognitive functions and recognition memory, along with reduction in anxiety-like behavior were also observed in the treated animals. Histopathological examination by Nissl staining showed reduction in neuronal damage in the hippocampal pyramidal layer. The dentate gyrus and Cornu Ammonis 3 regions of the hippocampus showed reduction in mossy fiber sprouting. GBbf treatment attenuated ribosomal S6 and pS6 proteins, and hippocampal mTOR, Rps6 and Rps6kb1 mRNA levels. The results of present study concluded that GBbf treatment suppressed lithium-pilocarpine induced spontaneous recurrent seizures severity and incidence with improved cognitive functions, reduced anxiety-like behavior and aggression. The effect was found to be due to inhibition of mTOR pathway hyperactivation linked with recurrent seizures. Copyright © 2017. Published by Elsevier B.V.

Z-Guggulsterone Produces Antidepressant-Like Effects in Mice through Activation of the BDNF Signaling Pathway

PubMed Central

Liu, Feng-Guo; Hu, Wen-Feng; Wang, Ji-Li; Wang, Peng; Gong, Yu; Tong, Li-Juan; Jiang, Bo; Zhang, Wei; Qin, Yi-Bin; Chen, Zhuo

2017-01-01

Abstract Background: Z-guggulsterone, an active compound extracted from the gum resin of the tree Commiphora mukul, has been shown to improve animal memory deficits via activating the brain-derived neurotrophic factor signaling pathway. Here, we investigated the antidepressant-like effect of Z-guggulsterone in a chronic unpredictable stress mouse model of depression. Methods: The effects of Z-guggulsterone were assessed in mice with the tail suspension test and forced swimming test. Z-guggulsterone was also investigated in the chronic unpredictable stress model of depression with fluoxetine as the positive control. Changes in hippocampal neurogenesis as well as the brain-derived neurotrophic factor signaling pathway after chronic unpredictable stress/Z-guggulsterone treatment were investigated. The tryptophan hydroxylase inhibitor and the tyrosine kinase B inhibitor were also used to explore the antidepressant-like mechanisms of Z-guggulsterone. Results: Z-guggulsterone (10, 30 mg/kg) administration protected the mice against the chronic unpredictable stress-induced increases in the immobile time in the tail suspension test and forced swimming test and also reversed the reduction in sucrose intake in sucrose preference experiment. Z-guggulsterone (10, 30 mg/kg) administration prevented the reductions in brain-derived neurotrophic factor protein expression levels as well as the phosphorylation levels of cAMP response element binding protein, extracellular signal-regulated kinase 1/2, and protein kinase B in the hippocampus and cortex induced by chronic unpredictable stress. Z-guggulsterone (10, 30 mg/kg) treatment also improved hippocampal neurogenesis in chronic unpredictable stress-treated mice. Blockade of the brain-derived neurotrophic factor signal, but not the monoaminergic system, attenuated the antidepressant-like effects of Z-guggulsterone. Conclusions: Z-guggulsterone exhibits antidepressant activity via activation of the brain-derived neurotrophic factor signaling pathway and upregulation of hippocampal neurogenesis. PMID:28339691

Dendrosomatic Sonic Hedgehog Signaling in Hippocampal Neurons Regulates Axon Elongation

PubMed Central

Petralia, Ronald S.; Ott, Carolyn; Wang, Ya-Xian; Lippincott-Schwartz, Jennifer; Mattson, Mark P.

2015-01-01

The presence of Sonic Hedgehog (Shh) and its signaling components in the neurons of the hippocampus raises a question about what role the Shh signaling pathway may play in these neurons. We show here that activation of the Shh signaling pathway stimulates axon elongation in rat hippocampal neurons. This Shh-induced effect depends on the pathway transducer Smoothened (Smo) and the transcription factor Gli1. The axon itself does not respond directly to Shh; instead, the Shh signal transduction originates from the somatodendritic region of the neurons and occurs in neurons with and without detectable primary cilia. Upon Shh stimulation, Smo localization to dendrites increases significantly. Shh pathway activation results in increased levels of profilin1 (Pfn1), an actin-binding protein. Mutations in Pfn1's actin-binding sites or reduction of Pfn1 eliminate the Shh-induced axon elongation. These findings indicate that Shh can regulate axon growth, which may be critical for development of hippocampal neurons. SIGNIFICANCE STATEMENT Although numerous signaling mechanisms have been identified that act directly on axons to regulate their outgrowth, it is not known whether signals transduced in dendrites may also affect axon outgrowth. We describe here a transcellular signaling pathway in embryonic hippocampal neurons in which activation of Sonic Hedgehog (Shh) receptors in dendrites stimulates axon growth. The pathway involves the dendritic-membrane-associated Shh signal transducer Smoothened (Smo) and the transcription factor Gli, which induces the expression of the gene encoding the actin-binding protein profilin 1. Our findings suggest scenarios in which stimulation of Shh in dendrites results in accelerated outgrowth of the axon, which therefore reaches its presumptive postsynaptic target cell more quickly. By this mechanism, Shh may play critical roles in the development of hippocampal neuronal circuits. PMID:26658865

Silibinin induces mitochondrial NOX4-mediated endoplasmic reticulum stress response and its subsequent apoptosis.

PubMed

Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Seo, Young-Kyo; Chun, Sung-Sik; Yu, Hak-Sun; Ahn, Soon-Cheol

2016-07-12

Silibinin, a biologically active compound of milk thistle, has chemopreventive effects on cancer cell lines. Recently it was reported that silibinin inhibited tumor growth through activation of the apoptotic signaling pathway. Although various evidences showed multiple signaling pathways of silibinin in apoptosis, there were no reports to address the clear mechanism of ROS-mediated pathway in prostate cancer PC-3 cells. Several studies suggested that reactive oxygen species (ROS) play an important role in various signaling cascades, but the primary source of ROS was currently unclear. The effect of silibinin was investigated on cell growth of prostate cell lines by MTT assay. We examined whether silibinin induced apoptosis through production of ROS using flow cytometry. Expression of apoptosis-, endoplasmic reticulum (ER)-related protein and gene were determined by western blotting and RT-PCR, respectively. Results showed that silibinin triggered mitochondrial ROS production through NOX4 expression and finally led to induce apoptosis. In addition, mitochondrial ROS caused ER stress through disruption of Ca(2+) homeostasis. Co-treatment of ROS inhibitor reduced the silibinin-induced apoptosis through the inhibition of NOX4 expression, resulting in reduction of both Ca(2+) level and ER stress response. Taken together, silibinin induced mitochondrial ROS-dependent apoptosis through NOX4, which is associated with disruption of Ca(2+) homeostasis and ER stress response. Therefore, the regulation of NOX4, mitochondrial ROS producer, could be a potential target for the treatment of prostate cancer.

Berberine inhibits macrophage M1 polarization via AKT1/SOCS1/NF-κB signaling pathway to protect against DSS-induced colitis.

PubMed

Liu, Yunxin; Liu, Xiang; Hua, Weiwei; Wei, Qingyan; Fang, Xianjun; Zhao, Zheng; Ge, Chun; Liu, Chao; Chen, Chen; Tao, Yifu; Zhu, Yubing

2018-04-01

Berberine has been reported to have protective effects in colitis treatment. However, the detailed mechanisms remain unclear. Herein, we demonstrated that berberine could protect against dextran sulfate sodium (DSS)-induced colitis in mice by regulating macrophage polarization. In the colitis mouse model, berberine ameliorated DSS-induced colon shortening and colon tissue injury. Moreover, berberine-treated mice showed significant reduction in the disease activity index (DAI), pro-inflammatory cytokines expression and macrophages infiltration compared with the DSS-treated mice. Notably, berberine significantly reduced the percentage of M1 macrophages. In vitro analysis also confirmed the inhibitory effects of berberine on macrophages M1 polarization in RAW267.4 cells. Further investigation showed that berberine promoted AKT1 expression in mRNA and protein level. Silence of AKT1 abolished the inhibitory effect of berberine on macrophages M1 polarization. The berberine-induced AKT1 expression promoted suppressers of cytokine signaling (SOCS1) activation, which inhibited nuclear factor-kappa B (NF-κB) phosphorylation. In addition, we also found that berberine activated AKT1/SOCS1 signaling pathway but inhibited p65 phosphorylation in macrophages in vivo. Therefore, we concluded that berberine played a regulatory role in macrophages M1 polarization in DSS-induced colitis via AKT1/SOCS1/NF-κB signaling pathway. This unexpected property of berberine may provide a potential explanation for its protective effects in colitis treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Redox Signaling via Oxidative Inactivation of PTEN Modulates Pressure-Dependent Myogenic Tone in Rat Middle Cerebral Arteries

PubMed Central

Gebremedhin, Debebe; Terashvili, Maia; Wickramasekera, Nadi; Zhang, David X.; Rau, Nicole; Miura, Hiroto; Harder, David R.

2013-01-01

The present study examined the level of generation of reactive oxygen species (ROS) and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 .−) and its dismutation product hydrogen peroxide (H2O2) as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol) or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca2+]i level in freshly isolated cerebral arterial muscle cells (CAMCs), responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction. PMID:23861911

Redox signaling via oxidative inactivation of PTEN modulates pressure-dependent myogenic tone in rat middle cerebral arteries.

PubMed

Gebremedhin, Debebe; Terashvili, Maia; Wickramasekera, Nadi; Zhang, David X; Rau, Nicole; Miura, Hiroto; Harder, David R

2013-01-01

The present study examined the level of generation of reactive oxygen species (ROS) and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 (.-)) and its dismutation product hydrogen peroxide (H2O2) as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol) or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca(2+)]i level in freshly isolated cerebral arterial muscle cells (CAMCs), responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction.

SIRT2 Inhibition Confers Neuroprotection by Downregulation of FOXO3a and MAPK Signaling Pathways in Ischemic Stroke.

PubMed

She, David T; Wong, Lap Jack; Baik, Sang-Ha; Arumugam, Thiruma V

2018-04-14

Sirtuin 2 (SIRT2) is a family member of nicotinamide adenine dinucleotide (NAD + )-dependent deacetylases which appears to have detrimental roles in an array of neurological disorders such as Parkinson's disease (PD) and Huntington's disease (HD). In light of the recently emerging roles of sirtuins in normal physiology and pathological conditions such as ischemic stroke, we investigated the role of SIRT2 in ischemic stroke-induced neuronal cell death. Primary cortical neurons were subjected to oxygen-glucose deprivation (OGD) under in vitro ischemic conditions, and subsequently tested for the efficacy of SIRT2 inhibitors AK1 and AGK2 in attenuating apoptotic cell death caused by OGD. We have also evaluated the effect of SIRT2 inhibition in C57BL/6 mice subjected to 1 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion, which is a model for ischemic reperfusion injury in vivo. Significant reductions in apoptotic cell death were noted in neurons treated with AK1 or AGK2, as evidenced by reduced cleaved caspase-3 and other apoptotic markers such as Bim and Bad. In addition, downregulation of phosphorylated-AKT and FOXO3a proteins of the AKT/FOXO3a pathway, as well as a marked reduction of JNK activity and its downstream target c-Jun, were also observed. When tested in animals subjected to MCAO, the neuroprotective effects of AGK2 in vivo were evidenced by a substantial reduction in ipsilateral infarct area and a significant improvement in neurological outcomes. A similar reduction in the levels of pro-apoptotic proteins in the infarct tissue, as well as downregulation of AKT/FOXO3a and JNK pathway, were also noted. In summary, the current study demonstrated the neuroprotective effects of SIRT2 inhibition in ischemic stroke, and identified the downregulation of AKT/FOXO3a and MAPK pathways as intermediary mechanisms which may contribute to the reduction in apoptotic cell death by SIRT2 inhibition.

Activation of the Phosphatidylinositol 3-Kinase/Akt Signaling Pathway during Porcine Circovirus Type 2 Infection Facilitates Cell Survival and Viral Replication

PubMed Central

Wei, Li; Zhu, Shanshan; Wang, Jing

2012-01-01

Virus infection activates host cellular signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which regulates diverse cellular activities related to cell growth, survival, and apoptosis. The present study demonstrated for the first time that porcine circovirus type 2 (PCV2), a major causative agent of postweaning multisystemic wasting syndrome, which is an emerging and important swine disease, can transiently induce the PI3K/Akt pathway in cultured cells at an early step during PCV2 infection. Activation of the PI3K/Akt signal was also induced by UV-irradiated PCV2, indicating that virus replication was not required for this induction. Inhibition of PI3K activation leads to reduced virus yield, which is associated with decreased viral DNA replication and lower virus protein expression. However, inhibition of PI3K activation greatly enhanced apoptotic responses as evidenced by the cleavage of poly-ADP ribose polymerase and caspase-3 as well as DNA fragmentation using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling staining during the early stage of PCV2 infection. Furthermore, the pancaspase inhibitor zVAD.fmk alleviated the reduction in Akt phosphorylation levels by inhibiting PI3K activation, indicating that the signaling promotes cell survival and thereby favors viral replication. These results reveal that an antiapoptotic role for the PI3K/Akt pathway induced by PCV2 infection to suppress premature apoptosis for improved virus growth after infection, extending our understanding of the molecular mechanism of PCV2 infection. PMID:23035228

UDCA and CDCA alleviate 17α-ethinylestradiol-induced cholestasis through PKA-AMPK pathways in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xiaojiaoyang; Yuan, Zihang

Estrogen-induced cholestasis, known as intrahepatic cholestasis of pregnancy (ICP), is an estrogen-related liver disease that is widely recognized as female or pregnancy-specific. Our previous findings showed that the synthetic estrogen, 17α-ethinylestradiol (EE), induced cholestatic injury through ERK1/2-LKB1-AMP-activated protein kinase (AMPK) signaling pathway and its mediated suppression of farnesoid X receptor (FXR). To investigate the role played by bile acids in EE-induced cholestasis, we evaluated the effects of chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) on sandwich cultured rat primary hepatocytes (SCRHs) and an in vivo rat model. Our results showed that, both CDCA and UDCA significantly inducedmore » time- and concentration-dependent reduction in AMPK phosphorylation in SCRHs. Despite having different effects on FXR activation, CDCA and UDCA both inhibited EE-induced AMPK activation, accompanied with the up-regulation of FXR and its downstream bile acid transporters. However, although DCA activates FXR and induces SHP, it was unable to alleviate EE-induced FXR suppression and further aggravated EE-induced cholestasis. We further demonstrated that both CDCA and UDCA, but not DCA, activated cyclic AMP dependent protein kinase (PKA) in SCRHs and the livers of male rats (8 weeks old) liver. Furthermore, PKA antagonist, H89, blocked the AMPK inhibition by CDCA and UDCA, and pharmacological and genetic activation of PKA suppressed EE-induced AMPK activation and its downstream effects. Collectively, these results suggest that CDCA and UDCA protect against estrogen-induced cholestatic injury via PKA signaling pathway and up-regulation of EE-suppressed FXR, which suggests a potential therapeutic target for ICP. - Highlights: • AMPK is involved in cholestatic liver injury with bile acid dysregulation. • CDCA and UDCA inhibit the phosphorylation of AMPK and alleviate estrogen-induced cholestasis. • PKA activation contributes to the CDCA- and UDCA-induced protective effects. • FXR up-regulation may be critical for improvement of cholestasis.« less

Demodex canis regulates cholinergic system mediated immunosuppressive pathways in canine demodicosis.

PubMed

Kumari, P; Nigam, R; Singh, A; Nakade, U P; Sharma, A; Garg, S K; Singh, S K

2017-09-01

Demodex canis infestation in dogs remains one of the main challenges in veterinary dermatology. The exact pathogenesis of canine demodicosis is unknown but an aberration in immune status is considered very significant. No studies have underpinned the nexus between induction of demodicosis and neural immunosuppressive pathways so far. We have evaluated the involvement of cholinergic pathways in association with cytokines regulation as an insight into the immuno-pathogenesis of canine demodicosis in the present study. Remarkable elevations in circulatory immunosuppressive cytokine interleukin-10 and cholinesterase activity were observed in dogs with demodicosis. Simultaneously, remarkable reduction in circulatory pro-inflammatory cytokine tumour necrosis factor-alpha level was observed in dogs with demodicosis. Findings of the present study evidently suggest that Demodex mites might be affecting the cholinergic pathways to induce immunosuppression in their host and then proliferate incessantly in skin microenvironment to cause demodicosis.

Protein kinase C mediates platelet secretion and thrombus formation through protein kinase D2.

PubMed

Konopatskaya, Olga; Matthews, Sharon A; Harper, Matthew T; Gilio, Karen; Cosemans, Judith M E M; Williams, Christopher M; Navarro, Maria N; Carter, Deborah A; Heemskerk, Johan W M; Leitges, Michael; Cantrell, Doreen; Poole, Alastair W

2011-07-14

Platelets are highly specialized blood cells critically involved in hemostasis and thrombosis. Members of the protein kinase C (PKC) family have established roles in regulating platelet function and thrombosis, but the molecular mechanisms are not clearly understood. In particular, the conventional PKC isoform, PKCα, is a major regulator of platelet granule secretion, but the molecular pathway from PKCα to secretion is not defined. Protein kinase D (PKD) is a family of 3 kinases activated by PKC, which may represent a step in the PKC signaling pathway to secretion. In the present study, we show that PKD2 is the sole PKD member regulated downstream of PKC in platelets, and that the conventional, but not novel, PKC isoforms provide the upstream signal. Platelets from a gene knock-in mouse in which 2 key phosphorylation sites in PKD2 have been mutated (Ser707Ala/Ser711Ala) show a significant reduction in agonist-induced dense granule secretion, but not in α-granule secretion. This deficiency in dense granule release was responsible for a reduced platelet aggregation and a marked reduction in thrombus formation. Our results show that in the molecular pathway to secretion, PKD2 is a key component of the PKC-mediated pathway to platelet activation and thrombus formation through its selective regulation of dense granule secretion.

Curcumin inhibits proliferation and induces apoptosis of human colorectal cancer cells by activating the mitochondria apoptotic pathway.

PubMed

Guo, Li-da; Chen, Xue-Jie; Hu, Yu-Hong; Yu, Zhi-Jun; Wang, Duo; Liu, Jing-Ze

2013-03-01

Curcumin, a natural plant extract from Curcuma longa, is known for its anti-carcinogenic and chemopreventive effects on a variety of experimental cancer models. In this study, we evaluated the effects of curcumin and elucidated its mechanism in human colorectal carcinoma cells. Cell viability assay showed that curcumin significantly inhibited the growth of LoVo cells. Curcumin treatment induced the apoptosis accompanied by ultra-structural changes and release of lactate dehydrogenase in a dose-dependent manner. Moreover, treatment with 0-30 µg/mL curcumin decreased the mitochondrial membrane potential and activated the caspase-3 and caspase-9 in a dose- and time-dependent manner. Nuclear and annexin V/PI staining showed that curcumin induced the apoptosis of LoVo cells. FACS analysis revealed that curcumin could induce the cell cycle arrest of LoVo cells at the S phase. Furthermore, western blotting analysis indicated that curcumin induced the release of cytochrome c, a significant increase of Bax and p53 and a marked reduction of Bcl-2 and survivin in LoVo cells. Taken together, our results suggested that curcumin inhibited the growth of LoVo cells by inducing apoptosis through a mitochondria-mediated pathway. Copyright © 2012 John Wiley & Sons, Ltd.

The Protective Effect of Gangliosides on Lead (Pb)-Induced Neurotoxicity Is Mediated by Autophagic Pathways.

PubMed

Meng, Hongtao; Wang, Lan; He, Junhong; Wang, Zhufeng

2016-03-25

Lead (Pb) is a ubiquitous environmental and industrial pollutant and can affect intelligence development and the learning ability and memory of children. Therefore, necessary measures should be taken to protect the central nervous system (CNS) from Pb toxicity. Gangliosides are sialic acid-containing glycosphingolipids that are constituents of mammalian cell membranes and are more abundantly expressed in the CNS. Studies have shown that gangliosides constitute a useful tool in the attempt to promote functional recovery of CNS and can reverse Pb-induced impairments of synaptic plasticity in rats. However, the detailed mechanisms have yet to be fully understood. In our present study, we tried to investigate the role of gangliosides in Pb-induced injury in hippocampus neurons and to further confirm the detailed mechanism. Our results show that Pb-induced injuries in the spatial reference memory were associated with a reduction of cell viability and cell apoptosis, and treatment with gangliosides markedly ameliorated the Pb-induced injury by inhibition of apoptosis action. Gangliosides further attenuated Pb-induced the abnormal autophagic process by regulation of mTOR pathways. In summary, our study establishes the efficacy of gangliosides as neuroprotective agents and provides a strong rationale for further studies on the underlying mechanisms of their neuroprotective functions.

Involvement of Caveolin in Low K+-induced Endocytic Degradation of Cell-surface Human Ether-a-go-go-related Gene (hERG) Channels*

PubMed Central

Massaeli, Hamid; Sun, Tao; Li, Xian; Shallow, Heidi; Wu, Jimmy; Xu, Jianmin; Li, Wentao; Hanson, Christian; Guo, Jun; Zhang, Shetuan

2010-01-01

Reduction in the rapidly activating delayed rectifier K+ channel current (IKr) due to either mutations in the human ether-a-go-go-related gene (hERG) or drug block causes inherited or drug-induced long QT syndrome. A reduction in extracellular K+ concentration ([K+]o) exacerbates long QT syndrome. Recently, we demonstrated that lowering [K+]o promotes degradation of IKr in rabbit ventricular myocytes and of the hERG channel stably expressed in HEK 293 cells. In this study, we investigated the degradation pathways of hERG channels under low K+ conditions. We demonstrate that under low K+ conditions, mature hERG channels and caveolin-1 (Cav1) displayed a parallel time-dependent reduction. Mature hERG channels coprecipitated with Cav1 in co-immunoprecipitation analysis, and internalized hERG channels colocalized with Cav1 in immunocytochemistry analysis. Overexpression of Cav1 accelerated internalization of mature hERG channels in 0 mm K+o, whereas knockdown of Cav1 impeded this process. In addition, knockdown of dynamin 2 using siRNA transfection significantly impeded hERG internalization and degradation under low K+o conditions. In cultured neonatal rat ventricular myocytes, knockdown of caveolin-3 significantly impeded low K+o-induced reduction of IKr. Our data indicate that a caveolin-dependent endocytic route is involved in low K+o-induced degradation of mature hERG channels. PMID:20605793

Nitric oxide production from macrophages is regulated by arachidonic acid metabolites.

PubMed

Imai, Y; Kolb, H; Burkart, V

1993-11-30

In activated macrophages the inducible form of the enzyme nitric oxide (NO) synthase generates high amounts of the toxic mediator NO. After 20 h of treatment with LPS rat peritoneal macrophages release 12-16 nmol NO2-/10(5) cells which is detectable in the culture supernatant by the Griess reaction as a measure of NO formation. The addition of aminoguanidine (1 mM), a preferential inhibitor of the inducible NO-synthase, completely abolished NO2-accumulation. Incubation with indomethacin or acetyl-salicylic acid, preferential inhibitors of the cyclooxygenase pathway of the arachidonic acid metabolism, did not influence NO2- levels. Nordihydro-guaiaretic acid (50 microM), a preferential inhibitor of the lipoxygenase pathway, caused strong reduction of NO2- accumulation to 1.9 +/- 0.3 nmol/200 microliter. Simultaneous inhibition of cyclo- and lipoxygenase by BW755c resulted in an intermediate effect (7.3 +/- 1.1 nmol/200 microliter NO2-). These results show that the induction of NO production in activated macrophages is regulated by products of the lipoxygenase-pathway of the arachidonic acid metabolism.

Activity-dependent downregulation of M-Type (Kv7) K⁺ channels surface expression requires the activation of iGluRs/Ca²⁺/PKC signaling pathway in hippocampal neuron.

PubMed

Li, Cai; Lu, Qing; Huang, Pengcheng; Fu, Tianli; Li, Changjun; Guo, Lianjun; Xu, Xulin

2015-08-01

M-type (Kv7) K(+) channels, encoded by KCNQ2-KCNQ5 genes, play a pivotal role in controlling neuronal excitability. However, precisely how neuronal activity regulates Kv7 channel translocation has not yet been fully defined. Here we reported activity-dependent changes in Kv7 channel subunits Kv7.2 and Kv7.3 surface expression by glutamate (glu). In the present study, we found that treatment with glutamate rapidly caused a specific decrease in M-current as well as Kv7 channel surface expression in primary cultured hippocampal neurons. The glutamate effects were mimicked by NMDA and AMPA. The glutamate effects on Kv7 channels were partially attenuated by pre-treatment of NMDA receptors antagonist d,l-APV or AMPA-KA receptors antagonist CNQX. The signal required Ca(2+) influx through L-type Ca(2+) channel and intracellular Ca(2+) elevations. PKC activation was involved in the glutamate-induced reduction of Kv7 channel surface expression. Moreover, a significant reduction of Kv7 channel surface expression occurred following glycine-induced "chem"-LTP in vitro and hippocampus-dependent behavioral learning training in vivo. These results demonstrated that activity-dependent reduction of Kv7 channel surface expression through activation of ionotropic glutamate receptors (iGluRs)/Ca(2+)/PKC signaling pathway might be an important molecular mechanism for regulation of neuronal excitability and synaptic plasticity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neurodegeneration Alters Metabolic Profile and Sirt 1 Signaling in High-Fat-Induced Obese Mice.

PubMed

Lima, Leandro Ceotto Freitas; Saliba, Soraya Wilke; Andrade, João Marcus Oliveira; Cunha, Maria Luisa; Cassini-Vieira, Puebla; Feltenberger, John David; Barcelos, Lucíola Silva; Guimarães, André Luiz Sena; de-Paula, Alfredo Mauricio Batista; de Oliveira, Antônio Carlos Pinheiro; Santos, Sérgio Henrique Sousa

2017-07-01

Different factors may contribute to the development of neurodegenerative diseases. Among them, metabolic syndrome (MS), which has reached epidemic proportions, has emerged as a potential element that may be involved in neurodegeneration. Furthermore, studies have shown the importance of the sirtuin family in neuronal survival and MS, which opens the possibility of new pharmacological targets. This study investigates the influence of sirtuin metabolic pathways by examining the functional capacities of glucose-induced obesity in an excitotoxic state induced by a quinolinic acid (QA) animal model. Mice were divided into two groups that received different diets for 8 weeks: one group received a regular diet, and the other group received a high-fat diet (HF) to induce MS. The animals were submitted to a stereotaxic surgery and subdivided into four groups: Standard (ST), Standard-QA (ST-QA), HF and HF-QA. The QA groups were given a 250 nL quinolinic acid injection in the right striatum and PBS was injected in the other groups. Obese mice presented with a weight gain of 40 % more than the ST group beyond acquiring an insulin resistance. QA induced motor impairment and neurodegeneration in both ST-QA and HF-QA, although no difference was observed between these groups. The HF-QA group showed a reduction in adiposity when compared with the groups that received PBS. Therefore, the HF-QA group demonstrated a commitment-dependent metabolic pathway. The results suggest that an obesogenic diet does not aggravate the neurodegeneration induced by QA. However, the excitotoxicity induced by QA promotes a sirtuin pathway impairment that contributes to metabolic changes.

Downregulation of VRK1 by p53 in Response to DNA Damage Is Mediated by the Autophagic Pathway

PubMed Central

Valbuena, Alberto; Castro-Obregón, Susana; Lazo, Pedro A.

2011-01-01

Human VRK1 induces a stabilization and accumulation of p53 by specific phosphorylation in Thr18. This p53 accumulation is reversed by its downregulation mediated by Hdm2, requiring a dephosphorylated p53 and therefore also needs the removal of VRK1 as stabilizer. This process requires export of VRK1 to the cytosol and is inhibited by leptomycin B. We have identified that downregulation of VRK1 protein levels requires DRAM expression, a p53-induced gene. DRAM is located in the endosomal-lysosomal compartment. Induction of DNA damage by UV, IR, etoposide and doxorubicin stabilizes p53 and induces DRAM expression, followed by VRK1 downregulation and a reduction in p53 Thr18 phosphorylation. DRAM expression is induced by wild-type p53, but not by common human p53 mutants, R175H, R248W and R273H. Overexpression of DRAM induces VRK1 downregulation and the opposite effect was observed by its knockdown. LC3 and p62 were also downregulated, like VRK1, in response to UV-induced DNA damage. The implication of the autophagic pathway was confirmed by its requirement for Beclin1. We propose a model with a double regulatory loop in response to DNA damage, the accumulated p53 is removed by induction of Hdm2 and degradation in the proteasome, and the p53-stabilizer VRK1 is eliminated by the induction of DRAM that leads to its lysosomal degradation in the autophagic pathway, and thus permitting p53 degradation by Hdm2. This VRK1 downregulation is necessary to modulate the block in cell cycle progression induced by p53 as part of its DNA damage response. PMID:21386980

Sulfur mustard analog, 2-chloroethyl ethyl sulfide-induced skin injury involves DNA damage and induction of inflammatory mediators, in part via oxidative stress, in SKH-1 hairless mouse skin

PubMed Central

Jain, Anil K.; Tewari-Singh, Neera; Gu, Mallikarjuna; Inturi, Swetha; White, Carl W.; Agarwal, Rajesh

2011-01-01

Bifunctional alkyalating agent, Sulfur mustard (SM)-caused cutaneous injury is characterized by inflammation and delayed blistering. Our recent studies demonstrated that 2-chloroethyl ethyl sulfide (CEES), a monofunctional analog of SM that can be used in laboratory settings, induces oxidative stress. This could be the major cause of the activation of Akt/MAP kinase and AP1/NF-κB pathways that are linked to the inflammation and microvesication, and histopathological alterations in SKH-1 hairless mouse skin. To further establish a link between CEES-induced DNA damage and signaling pathways and inflammatory responses, skin samples from mice exposed to 2 or 4 mg CEES for 9–48 h were subjected to molecular analysis. Our results show a strong CEES-induced phosphorylation of H2A.X and an increase in COX-2, iNOS, and MMP-9 levels, indicating the involvement of DNA damage and inflammation in CEES-caused skin injury in male and female mice. Since, our recent studies showed reduction in CEES-induced inflammatory responses by glutathione (GSH), we further assessed the role of oxidative stress in CEES-caused DNA damage and the induction of inflammatory molecules. Oral GSH (300mg/kg) administration 1 h before CEES exposure attenuated the increase in both CEES-induced H2A.X phosphorylation (59%) as well as expression of COX-2 (68%), iNOS (53%) and MMP-9 (54%). Collectively, our results indicate that CEES-induced skin injuries involve DNA damage and an induction of inflammatory mediators, at least in part via oxidative stress. This study could help in identifying countermeasures that alone or in combination, can target the unveiled pathways for reducing skin injuries in humans by SM. PMID:21722719

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Qiwen; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009; Bijie Pilot Area Research Institute of Bijie University, Bijie 551700

Highlights: •Cadmium can promote early upregulation of autophagy in PC-12 cells. •Autophagy precedes apoptosis in cadmium-treated PC-12 cells. •Cadmium-induced autophagy is cytoprotective in PC-12 cells. •Class III PI3K/beclin-1/Bcl-2 signaling pathway plays a positive role in cadmium-triggered autophagy. -- Abstract: Laboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased,more » and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity.« less

Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice.

PubMed

Liu, Xiao-Long; Luo, Liu; Mu, Rong-Hao; Liu, Bin-Bin; Geng, Di; Liu, Qing; Yi, Li-Tao

2015-11-02

Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus.

Competing charge transfer pathways at the photosystem II-electrode interface

PubMed Central

Zhang, Jenny Z.; Sokol, Katarzyna P.; Paul, Nicholas; Romero, Elisabet; van Grondelle, Rienk; Reisner, Erwin

2016-01-01

The integration of the water-oxidation enzyme, photosystem II (PSII), into electrodes allows the electrons extracted from water-oxidation to be harnessed for enzyme characterization and driving novel endergonic reactions. However, PSII continues to underperform in integrated photoelectrochemical systems despite extensive optimization efforts. Here, we performed protein-film photoelectrochemistry on spinach and Thermosynechococcus elongatus PSII, and identified a competing charge transfer pathway at the enzyme-electrode interface that short-circuits the known water-oxidation pathway: photo-induced O2 reduction occurring at the chlorophyll pigments. This undesirable pathway is promoted by the embedment of PSII in an electron-conducting matrix, a common strategy of enzyme immobilization. Anaerobicity helps to recover the PSII photoresponses, and unmasked the onset potentials relating to the QA/QB charge transfer process. These findings have imparted a fuller understanding of the charge transfer pathways within PSII and at photosystem-electrode interfaces, which will lead to more rational design of pigment-containing photoelectrodes in general. PMID:27723748

IGF-1 protects SH-SY5Y cells against MPP+-induced apoptosis via PI3K/PDK-1/Akt pathway.

PubMed

Kim, Chanyang; Park, Seungjoon

2018-03-01

Insulin-like growth factor (IGF)-1 is a well-known anti-apoptotic pro-survival factor and phosphatidylinositol-3-kinase (PI3K)/Akt pathway is linked to cell survival induced by IGF-1. It is also reported that Akt signaling is modulated by 3-phosphoinositide-dependent kinase-1 (PDK1). In the current study, we investigated whether the anti-apoptotic effect of IGF-1 in SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP + ) is associated with the activity of PI3K/PDK1/Akt pathway. Treatment of cells with IGF-1 inhibited MPP + -induced apoptotic cell death. IGF-1-induced activation of Akt and the protective effect of IGF-1 on MPP + -induced apoptosis were abolished by chemical inhibition of PDK1 (GSK2334470) or PI3K (LY294002). The phosphorylated levels of Akt and PDK1 were significantly suppressed after MPP + exposure, while IGF-1 treatment completely restored MPP+-induced reductions in phosphorylation. IGF-1 protected cells from MPP + insult by suppressing intracellular reactive oxygen species (ROS) production and malondialdehyde levels and increasing superoxide dismutase activity. Mitochondrial ROS levels were also increased during MPP + exposure, which were attenuated by IGF-1 treatment. In addition, IGF-1-treated cells showed increased activities of succinate dehydrogenase and citrate synthase, stabilization of mitochondrial transmembrane potential, increased ratio of Bcl-2 to Bax, prevention of cytochrome c release and inhibition of caspase-3 activation with PARP cleavage. Furthermore, the protective effects of IGF-1 on oxidative stress and mitochondrial dysfunction were attenuated when cells were preincubated with GSK2334470 or LY294002. Our data suggest that IGF-1 protects SH-SY5Y cells against MPP + -associated oxidative stress by preserving mitochondrial integrity and inhibiting mitochondrial apoptotic cascades via the activation of PI3K/PDK1/Akt pathway. © 2018 The authors.

IGF-1 protects SH-SY5Y cells against MPP+-induced apoptosis via PI3K/PDK-1/Akt pathway

PubMed Central

Kim, Chanyang; Park, Seungjoon

2018-01-01

Insulin-like growth factor (IGF)-1 is a well-known anti-apoptotic pro-survival factor and phosphatidylinositol-3-kinase (PI3K)/Akt pathway is linked to cell survival induced by IGF-1. It is also reported that Akt signaling is modulated by 3-phosphoinositide-dependent kinase-1 (PDK1). In the current study, we investigated whether the anti-apoptotic effect of IGF-1 in SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP+) is associated with the activity of PI3K/PDK1/Akt pathway. Treatment of cells with IGF-1 inhibited MPP+-induced apoptotic cell death. IGF-1-induced activation of Akt and the protective effect of IGF-1 on MPP+-induced apoptosis were abolished by chemical inhibition of PDK1 (GSK2334470) or PI3K (LY294002). The phosphorylated levels of Akt and PDK1 were significantly suppressed after MPP+ exposure, while IGF-1 treatment completely restored MPP+-induced reductions in phosphorylation. IGF-1 protected cells from MPP+ insult by suppressing intracellular reactive oxygen species (ROS) production and malondialdehyde levels and increasing superoxide dismutase activity. Mitochondrial ROS levels were also increased during MPP+ exposure, which were attenuated by IGF-1 treatment. In addition, IGF-1-treated cells showed increased activities of succinate dehydrogenase and citrate synthase, stabilization of mitochondrial transmembrane potential, increased ratio of Bcl-2 to Bax, prevention of cytochrome c release and inhibition of caspase-3 activation with PARP cleavage. Furthermore, the protective effects of IGF-1 on oxidative stress and mitochondrial dysfunction were attenuated when cells were preincubated with GSK2334470 or LY294002. Our data suggest that IGF-1 protects SH-SY5Y cells against MPP+-associated oxidative stress by preserving mitochondrial integrity and inhibiting mitochondrial apoptotic cascades via the activation of PI3K/PDK1/Akt pathway. PMID:29459421

Developmentally Regulated Sesquiterpene Production Confers Resistance to Colletotrichum gloeosporioides in Ripe Pepper Fruits

PubMed Central

Im, Soonduk; Han, Yun-Jeong; Lee, Sungbeom; Back, Kyoungwhan; Kim, Jeong-Il; Kim, Young Soon

2014-01-01

Sesquiterpenoid capsidiol, exhibiting antifungal activity against pathogenic fungus, is accumulated in infected ripe pepper fruits. In this study, we found a negative relation between the capsidiol level and lesion size in fruits infected with Colletotrichum gloeosporioides, depending on the stage of ripening. To understand the developmental regulation of capsidiol biosynthesis, fungal-induced gene expressions in the isoprenoid biosynthetic pathways were examined in unripe and ripe pepper fruits. The sterol biosynthetic pathway was almost shut down in healthy ripe fruits, showing very low expression of hydroxymethyl glutaryl CoA reductase (HMGR) and squalene synthase (SS) genes. In contrast, genes in the carotenoid pathway were highly expressed in ripe fruits. In the sesquiterpene pathway, 5-epi-aristolochene synthase (EAS), belonging to a sesquiterpene cyclase (STC) family, was significantly induced in the ripe fruits upon fungal infection. Immunoblot and enzyme activity analyses showed that the STCs were induced both in the infected unripe and ripe fruits, while capsidiol was synthesized discriminatively in the ripe fruits, implying diverse enzymatic specificity of multiple STCs. Thereby, to divert sterol biosynthesis into sesquiterpene production, infected fruits were pretreated with an SS inhibitor, zaragozic acid (ZA), resulting in increased levels of capsidiol by more than 2-fold in the ripe fruits, with concurrent reduction of phytosterols. Taken together, the present results suggest that the enhanced expression and activity of EAS in the ripe fruits play an important role in capsidiol production, contributing to the incompatibility between the anthracnose fungus and the ripe pepper fruits. PMID:25286411

Sulfur mustard analog, 2-chloroethyl ethyl sulfide-induced skin injury involves DNA damage and induction of inflammatory mediators, in part via oxidative stress, in SKH-1 hairless mouse skin.

PubMed

Jain, Anil K; Tewari-Singh, Neera; Gu, Mallikarjuna; Inturi, Swetha; White, Carl W; Agarwal, Rajesh

2011-09-10

Bifunctional alkyalating agent, sulfur mustard (SM)-induced cutaneous injury is characterized by inflammation and delayed blistering. Our recent studies demonstrated that 2-chloroethyl ethyl sulfide (CEES), a monofunctional analog of SM that can be used in laboratory settings, induces oxidative stress. This could be the major cause of the activation of Akt/MAP kinase and AP1/NF-κB pathways that are linked to the inflammation and microvesication, and histopathological alterations in SKH-1 hairless mouse skin. To further establish a link between CEES-induced DNA damage and signaling pathways and inflammatory responses, skin samples from mice exposed to 2 mg or 4 mg CEES for 9-48 h were subjected to molecular analysis. Our results show a strong CEES-induced phosphorylation of H2A.X and an increase in cyclooxygenase-2 (COX-2), inducible NOS (iNOS), and matrix metalloproteinase-9 (MMP-9) levels, indicating the involvement of DNA damage and inflammation in CEES-induced skin injury in male and female mice. Since, our recent studies showed reduction in CEES-induced inflammatory responses by glutathione (GSH), we further assessed the role of oxidative stress in CEES-related DNA damage and the induction of inflammatory molecules. Oral GSH (300 mg/kg) administration 1h before CEES exposure attenuated the increase in both CEES-induced H2A.X phosphorylation (59%) as well as expression of COX-2 (68%), iNOS (53%) and MMP-9 (54%). Collectively, our results indicate that CEES-induced skin injury involves DNA damage and an induction of inflammatory mediators, at least in part via oxidative stress. This study could help in identifying countermeasures that alone or in combination, can target the unveiled pathways for reducing skin injury in humans by SM. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Boosting the pentose phosphate pathway restores cardiac progenitor cell availability in diabetes.

PubMed

Katare, Rajesh; Oikawa, Atsuhiko; Cesselli, Daniela; Beltrami, Antonio P; Avolio, Elisa; Muthukrishnan, Deepti; Munasinghe, Pujika Emani; Angelini, Gianni; Emanueli, Costanza; Madeddu, Paolo

2013-01-01

Diabetes impinges upon mechanisms of cardiovascular repair. However, the biochemical adaptation of cardiac stem cells to sustained hyperglycaemia remains largely unknown. Here, we investigate the molecular targets of high glucose-induced damage in cardiac progenitor cells (CPCs) from murine and human hearts and attempt safeguarding CPC viability and function through reactivation of the pentose phosphate pathway. Type-1 diabetes was induced by streptozotocin. CPC abundance was determined by flow cytometry. Proliferating CPCs were identified in situ by immunostaining for the proliferation marker Ki67. Diabetic hearts showed marked reduction in CPC abundance and proliferation when compared with controls. Moreover, Sca-1(pos) CPCs isolated from hearts of diabetic mice displayed reduced activity of key enzymes of the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD), and transketolase, increased levels of superoxide and advanced glucose end-products (AGE), and inhibition of the Akt/Pim-1/Bcl-2 signalling pathway. Similarly, culture of murine CPCs or human CD105(pos) progenitor cells in high glucose inhibits the pentose phosphate and pro-survival signalling pathways, leading to the activation of apoptosis. In vivo and in vitro supplementation with benfotiamine reactivates the pentose phosphate pathway and rescues CPC availability and function. This benefit is abrogated by either G6PD silencing by small interfering RNA (siRNA) or Akt inhibition by dominant-negative Akt. We provide new evidence of the negative impact of diabetes and high glucose on mechanisms controlling CPC redox state and survival. Boosting the pentose phosphate pathway might represent a novel mechanistic target for protection of CPC integrity.

Boosting the pentose phosphate pathway restores cardiac progenitor cell availability in diabetes

PubMed Central

Katare, Rajesh; Oikawa, Atsuhiko; Cesselli, Daniela; Beltrami, Antonio P.; Avolio, Elisa; Muthukrishnan, Deepti; Munasinghe, Pujika Emani; Angelini, Gianni; Emanueli, Costanza; Madeddu, Paolo

2013-01-01

Aims Diabetes impinges upon mechanisms of cardiovascular repair. However, the biochemical adaptation of cardiac stem cells to sustained hyperglycaemia remains largely unknown. Here, we investigate the molecular targets of high glucose-induced damage in cardiac progenitor cells (CPCs) from murine and human hearts and attempt safeguarding CPC viability and function through reactivation of the pentose phosphate pathway. Methods and results Type-1 diabetes was induced by streptozotocin. CPC abundance was determined by flow cytometry. Proliferating CPCs were identified in situ by immunostaining for the proliferation marker Ki67. Diabetic hearts showed marked reduction in CPC abundance and proliferation when compared with controls. Moreover, Sca-1pos CPCs isolated from hearts of diabetic mice displayed reduced activity of key enzymes of the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD), and transketolase, increased levels of superoxide and advanced glucose end-products (AGE), and inhibition of the Akt/Pim-1/Bcl-2 signalling pathway. Similarly, culture of murine CPCs or human CD105pos progenitor cells in high glucose inhibits the pentose phosphate and pro-survival signalling pathways, leading to the activation of apoptosis. In vivo and in vitro supplementation with benfotiamine reactivates the pentose phosphate pathway and rescues CPC availability and function. This benefit is abrogated by either G6PD silencing by small interfering RNA (siRNA) or Akt inhibition by dominant-negative Akt. Conclusion We provide new evidence of the negative impact of diabetes and high glucose on mechanisms controlling CPC redox state and survival. Boosting the pentose phosphate pathway might represent a novel mechanistic target for protection of CPC integrity. PMID:22997160

Effect of CO, NOx and SO2 on ROS production, photosynthesis and ascorbate–glutathione pathway to induce Fragaria×annasa as a hyperaccumulator☆

PubMed Central

Muneer, Sowbiya; Kim, Tae Hwan; Choi, Byung Chul; Lee, Beom Seon; Lee, Jeong Hyun

2013-01-01

A study was conducted to determine the effect of carbon monoxide (CO), nitroxide (NOx) and sulfur dioxide (SO2) on ROS production, photosynthesis and ascorbate–glutathione pathway in strawberry plants. The results showed that both singlet oxygen (O2−1) and hydrogen peroxide (H2O2) content increased in CO, NOx and SO2 treated strawberry leaves. A drastic reduction of primary metabolism of plants (photosynthesis), with the closure of stomata, resulted in a reduction of protein, carbohydrate and sucrose content due to production of reactive oxygen species (ROS) under prolonged exposure of gas stress. The resulting antioxidant enzymes were increased under a low dose of gas stress, whereas they were decreased due to a high dose of gas stress. Our results indicate that increased ROS may act as a signal to induce defense responses to CO, NOx and SO2 gas stress. The increased level of antioxidant enzymes plays a significant role in plant protection due to which strawberry plants can be used as a hyperaccumulator to maintain environmental pollution, however, the defense capacity cannot sufficiently alleviate oxidative damage under prolonged exposure of CO, NOx and SO2 stress. PMID:25460723

FKBP12.6 protects heart from AngII-induced hypertrophy through inhibiting Ca2+ /calmodulin-mediated signalling pathways in vivo and in vitro.

PubMed

Xiao, Yun-Fei; Zeng, Zhi-Xiong; Guan, Xiao-Hui; Wang, Ling-Fang; Wang, Chan-Juan; Shi, Huidong; Shou, Weinian; Deng, Ke-Yu; Xin, Hong-Bo

2018-04-22

We previously observed that disruption of FK506-binding protein 12.6 (FKBP12.6) gene resulted in cardiac hypertrophy in male mice. Studies showed that overexpression of FKBP12.6 attenuated thoracic aortic constriction (TAC)-induced cardiac hypertrophy in mice, whereas the adenovirus-mediated overexpression of FKBP12.6 induced hypertrophy and apoptosis in cultured neonatal cardiomyocytes, indicating that the role of FKBP12.6 in cardiac hypertrophy is still controversial. In this study, we aimed to investigate the roles and mechanisms of FKBP12.6 in angiotensin II (AngII)-induced cardiac hypertrophy using various transgenic mouse models in vivo and in vitro. FKBP12.6 knockout (FKBP12.6 -/- ) mice and cardiac-specific FKBP12.6 overexpressing (FKBP12.6 TG) mice were infused with AngII (1500 ng/kg/min) for 14 days subcutaneously by implantation of an osmotic mini-pump. The results showed that FKBP12.6 deficiency aggravated AngII-induced cardiac hypertrophy, while cardiac-specific overexpression of FKBP12.6 prevented hearts from the hypertrophic response to AngII stimulation in mice. Consistent with the results in vivo, overexpression of FKBP12.6 in H9c2 cells significantly repressed the AngII-induced cardiomyocyte hypertrophy, seen as reductions in the cell sizes and the expressions of hypertrophic genes. Furthermore, we demonstrated that the protection of FKBP12.6 on AngII-induced cardiac hypertrophy was involved in reducing the concentration of intracellular Ca 2+ ([Ca 2+ ]i), in which the protein significantly inhibited the key Ca 2+ /calmodulin-dependent signalling pathways such as calcineurin/cardiac form of nuclear factor of activated T cells 4 (NFATc4), calmodulin kinaseII (CaMKII)/MEF-2, AKT/Glycogen synthase kinase 3β (GSK3β)/NFATc4 and AKT/mTOR signalling pathways. Our study demonstrated that FKBP12.6 protects heart from AngII-induced cardiac hypertrophy through inhibiting Ca 2+ /calmodulin-mediated signalling pathways. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

CCL11 promotes angiogenic activity by activating the PI3K/Akt pathway in HUVECs.

PubMed

Park, Jun Young; Kang, Yeo Wool; Choi, Byung Young; Yang, Young Chul; Cho, Byung Pil; Cho, Won Gil

2017-08-01

CCR3, the receptor for CCL11, is expressed on the surface of immune cells and even on non-immune cells. CCL11-CCR3 interactions can promote cell migration and proliferation. In this study, we investigated the effect of CCL11 on angiogenesis in HUVECs and also examined the molecular mechanisms of this process. We found that CCL11 induced mRNA transcription and protein expression of CCR3 in HUVECs. Moreover, the scratch wound healing assay and MTS proliferation assay both demonstrated that CCL11 promotes endothelial cell migration and induces weak proliferation. CCL11 directly induced microvessel sprouting from the rat aortic ring; these effects occurred earlier and to a greater extent than with VEGF stimulation. Furthermore, CCL11-induced phosphorylation of Akt was abolished by PI3K inhibitors. siRNA-mediated knockdown of CCR3 led to a significant reduction of PI3K phosphorylation. However, the phosphorylation levels of ERK1/2 were not changed, even after CCL11 treatment. Cumulatively, our data suggest that the CCL11-CCR3 interaction mainly activates PI3K/Akt signal transduction pathway in HUVECs.

Effect of uric acid on inflammatory COX-2 and ROS pathways in vascular smooth muscle cells.

PubMed

Oğuz, Nurgül; Kırça, Mustafa; Çetin, Arzu; Yeşilkaya, Akın

2017-10-01

Hyperuricemia is thought to play a role in cardiovascular diseases (CVD), including hypertension, coronary artery disease and atherosclerosis. However, exactly how uric acid contributes to these pathologies is unknown. An underlying mechanism of inflammatory diseases, such as atherosclerosis, includes enhanced production of cyclooxygenase-2 (COX-2) and superoxide anion. Here, we aimed to examine the effect of uric acid on inflammatory COX-2 and superoxide anion production and to determine the role of losartan. Primarily cultured vascular smooth muscle cells (VSMCs) were time and dose-dependently induced by uric acid and COX-2 and superoxide anion levels were measured. COX-2 levels were determined by ELISA, and superoxide anion was measured by the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c method. Uric acid elevated COX-2 levels in a time-dependent manner. Angiotensin-II receptor blocker, losartan, diminished uric-acid-induced COX-2 elevation. Uric acid also increased superoxide anion level in VSMCs. Uric acid plays an important role in CVD pathogenesis by inducing inflammatory COX-2 and ROS pathways. This is the first study demonstrating losartan's ability to reduce uric-acid-induced COX-2 elevation.

Boron Tolerance in Aspergillus nidulans Is Sustained by the SltA Pathway Through the SLC-Family Transporters SbtA and SbtB

PubMed Central

Villarino, María; Mendizabal, Gorka; Garzia, Aitor; Ugalde, Unai

2017-01-01

Microbial cells interact with the environment by adapting to external changes. Signal transduction pathways participate in both sensing and responding in the form of modification of gene expression patterns, enabling cell survival. The filamentous fungal-specific SltA pathway regulates tolerance to alkalinity, elevated cation concentrations and, as shown in this work, also stress conditions induced by borates. Growth of sltA− mutants is inhibited by increasing millimolar concentrations of boric acid or borax (sodium tetraborate). In an attempt to identify genes required for boron-stress response, we determined the boric acid or borax-dependent expression of sbtA and sbtB, orthologs of Saccharomyces cerevisiae bor1, and a reduction in their transcript levels in a ΔsltA mutant. Deletion of sbtA, but mainly that of sbtB, decreased the tolerance to boric acid or borax. In contrast, null mutants of genes coding for additional transporters of the Solute Carrier (SLC) family, sB, sbtD or sbtE, showed an unaltered growth pattern under the same stress conditions. Taken together, our results suggest that the SltA pathway induces, through SbtA and SbtB, the export of toxic concentrations of borates, which have largely recognized antimicrobial properties. PMID:28753996

Mechanisms of CCl4-induced liver fibrosis with combined transcriptomic and proteomic analysis.

PubMed

Dong, Shu; Chen, Qi-Long; Song, Ya-Nan; Sun, Yang; Wei, Bin; Li, Xiao-Yan; Hu, Yi-Yang; Liu, Ping; Su, Shi-Bing

2016-01-01

The classic toxicity of carbon tetrachloride (CCl4) is to induce liver lesion and liver fibrosis. Liver fibrosis is a consequence of chronic liver lesion, which can progress into liver cirrhosis even hepatocarcinoma. However, the toxicological mechanisms of CCl4-induced liver fibrosis remain not fully understood. We combined transcriptomic and proteomic analysis and biological network technology, predicted toxicological targets and regulatory networks of CCl4 in liver fibrosis. Wistar rats were treated with CCl4 for 9 weeks. Histopathological changes, hydroxyproline (Hyp) contents, serum ALT and AST in the CCl4-treated group were significantly higher than that of CCl4-untreated group. CCl4-treated and -untreated liver tissues were examined by microarray and iTRAQ. The results showed that 3535 genes (fold change ≥ 1.5, P < 0.05) and 1412 proteins (fold change ≥ 1.2, P < 0.05) were differentially expressed. Moreover, the integrative analysis of transcriptomics and proteomics data showed 523 overlapped proteins, enriched in 182 GO terms including oxidation reduction, response to oxidative stress, inflammatory response, extracellular matrix organization, etc. Furthermore, KEGG pathway analysis showed that 36 pathways including retinol metabolism, PPAR signaling pathway, glycolysis/gluconeogenesis, arachidonic acid metabolism, metabolism of xenobiotics by cytochrome P450 and drug metabolism. Network of protein-protein interaction (PPI) and key function with their related targets were performed and the degree of network was calculated with Cytoscape. The expression of key targets such as CYP4A3, ALDH2 and ALDH7A1 decreased after CCl4 treatment. Therefore, the toxicological mechanisms of CCl4-induced liver fibrosis may be related with multi biological process, pathway and targets which may provide potential protection reaction mechanism for CCl4 detoxication in the liver.

Cyanidin-3-glucoside attenuates angiotensin II-induced oxidative stress and inflammation in vascular endothelial cells.

PubMed

Sivasinprasasn, Sivanan; Pantan, Rungusa; Thummayot, Sarinthorn; Tocharus, Jiraporn; Suksamrarn, Apichart; Tocharus, Chainarong

2016-10-28

Angiotensin II (Ang II) causes oxidative stress and vascular inflammation, leading to vascular endothelial cell dysfunction, and is associated with the development of inflammatory cardiovascular diseases such as atherosclerosis. Therefore, interventions of oxidative stress and inflammation may contribute to the reduction of cardiovascular diseases. Cyanidin-3-glucoside (C3G) plays a role in the prevention of oxidative damage in several diseases. Here, we investigated the effect of C3G on Ang II-induced oxidative stress and vascular inflammation in human endothelial cells (EA.hy926). C3G dose-dependently suppressed the free radicals and inhibited the nuclear factor-kappa B (NF-κB) signaling pathway by protecting the degradation of inhibitor of kappa B-alpha (IκB-α), inhibiting the expression and translocation of NF-κB into the nucleus through the down-regulation of NF-κB p65 and reducing the expression of inducible nitric oxide synthase (iNOS). Pretreatment with C3G not only prohibited the NF-κB signaling pathway but also promoted the activity of the nuclear erythroid-related factor 2 (Nrf2) signaling pathway through the upregulation of endogenous antioxidant enzymes. Particularly, we observed that C3G significantly enhanced the production of superoxide dismutase (SOD) and induced the expression of heme oxygenase (HO-1). Our findings confirm that C3G can protect against vascular endothelial cell inflammation induced by AngII. C3G may represent a promising dietary supplement for the prevention of inflammation, thereby decreasing the risk for the development of atherosclerosis. Copyright © 2016. Published by Elsevier Ireland Ltd.

Induction of apoptosis by pinostrobin in human cervical cancer cells: Possible mechanism of action.

PubMed

Jaudan, Alka; Sharma, Sapna; Malek, Sri Nurestri Abd; Dixit, Aparna

2018-01-01

Pinostrobin (PN) is a naturally occurring dietary bioflavonoid, found in various medicinal herbs/plants. Though anti-cancer potential of many such similar constituents has been demonstrated, critical biochemical targets and exact mechanism for their apoptosis-inducing actions have not been fully elucidated. The present study was aimed to investigate if PN induced apoptosis in cervical cancer cells (HeLa) of human origin. It is demonstrated that PN at increasing dose effectivity reduced the cell viability as well as GSH and NO2- levels. Condensed nuclei with fragmented chromatin and changes in mitochondrial matrix morphology clearly indicated the role of mitochondria in PN induced apoptosis. A marked reduction in mitochondrial membrane potential and increased ROS production after PN treatment showed involvement of free radicals, which in turn further augment ROS levels. PN treatment resulted in DNA damage, which could have been triggered by an increase in ROS levels. Decrease in apoptotic cells in the presence of caspase 3 inhibitor in PN-treated cells suggested that PN induced apoptosis via caspase dependent pathways. Additionally, a significant increase in the expression of proteins of extrinsic (TRAIL R1/DR4, TRAIL R2/DR5, TNF RI/TNFRSF1A, FADD, Fas/TNFRSF6) and intrinsic pathway (Bad, Bax, HTRA2/Omi, SMAC/Diablo, cytochrome C, Pro-Caspase-3, Cleaved Caspase-3) was observed in the cells exposed to PN. Taken together, these observations suggest that PN efficiently induces apoptosis through ROS mediated extrinsic and intrinsic dependent signaling pathways, as well as ROS mediated mitochondrial damage in HeLa cells.

Ionizing radiation induces cellular senescence of articular chondrocytes via negative regulation of SIRT1 by p38 kinase.

PubMed

Hong, Eun-Hee; Lee, Su-Jae; Kim, Jae-Sung; Lee, Kee-Ho; Um, Hong-Duck; Kim, Jae-Hong; Kim, Song-Ja; Kim, Jong-Il; Hwang, Sang-Gu

2010-01-08

Radiotherapy is increasingly used in the treatment of joint diseases, but limited information is available on the effects of radiation on cartilage. Here, we characterize the molecular mechanisms leading to cellular senescence in irradiated primary cultured articular chondrocytes. Ionizing radiation (IR) causes activation of ERK, in turn generating intracellular reactive oxygen species (ROS) with induction of senescence-associated beta-galactosidase (SA-beta-gal) activity. ROS activate p38 kinase, which further promotes ROS generation, forming a positive feedback loop to sustain ROS-p38 kinase signaling. The ROS inhibitors, nordihydroguaiaretic acid and GSH, suppress phosphorylation of p38 and cell numbers positive for SA-beta-gal following irradiation. Moreover, inhibition of the ERK and p38 kinase pathways leads to blockage of IR-induced SA-beta-gal activity via reduction of ROS generation. Although JNK is activated by ROS, this pathway is not associated with cellular senescence of chondrocytes. Interestingly, IR triggers down-regulation of SIRT1 protein expression but not the transcript level, indicative of post-transcriptional cleavage of the protein. SIRT1 degradation is markedly blocked by SB203589 or MG132 after IR treatment, suggesting that cleavage occurs as a result of binding with p38 kinase, followed by processing via the 26 S proteasomal degradation pathway. Overexpression or activation of SIRT1 significantly reduces the IR-induced senescence phenotype, whereas inhibition of SIRT1 activity induces senescence. Based on these findings, we propose that IR induces cellular senescence of articular chondrocytes by negative post-translational regulation of SIRT1 via ROS-dependent p38 kinase activation.

Cigarette smoke exposure reveals a novel role for the MEK/ERK1/2 MAPK pathway in regulation of CFTR

PubMed Central

Xu, Xiaohua; Balsiger, Robert; Tyrrell, Jean; Boyaka, Prosper N.; Tarran, Robert; Cormet-Boyaka, Estelle

2015-01-01

Background CFTR plays a key role in maintenance of lung fluid homeostasis. Cigarette smoke decreases CFTR expression in the lung but neither the mechanisms leading to CFTR loss, nor potential ways to prevent its loss have been identified to date. Methods The molecular mechanisms leading to down-regulation of CFTR by cigarette smoke were determined using pharmacologic inhibitors and silencing RNAs. Results Using human bronchial epithelial cells, here we show that cigarette smoke induces degradation of CFTR that is attenuated by the lysosomal inhibitors, but not proteasome inhibitors. Cigarette smoke can activate multiple signaling pathways in airway epithelial cells, including the MEK/Erk1/2 MAPK pathway regulating cell survival. Interestingly, pharmacological inhibition of the MEK/Erk1/2 MAPK pathway prevented the loss of plasma membrane CFTR upon cigarette smoke exposure. Similarly, decreased expression of Erk1/2 using silencing RNAs prevented the suppression of CFTR protein by cigarette smoke. Conversely, specific inhibitors of the JNK or p38 MAPK pathways had no effect on CFTR decrease after cigarette smoke exposure. In addition, inhibition of the MEK/Erk1/2 MAPK pathway prevented the reduction of the airway surface liquid observed upon cigarette smoke exposure of primary human airway epithelial cells. Finally, addition of the antioxidant NAC inhibited activation of Erk1/2 by cigarette smoke and precluded the cigarette smoke-induced decrease of CFTR. Conclusions These results show that the MEK/Erk1/2 MAPK pathway regulates plasma membrane CFTR in human airway cells. General Significance The MEK/Erk1/2 MAPK pathway should be considered as a target for strategies to maintain/restore CFTR expression in the lung of smokers. PMID:25697727

Down-regulation of Homer1b/c protects against chemically induced seizures through inhibition of mTOR signaling.

PubMed

Cao, Lei; Tian, Ye; Jiang, Yi; Zhang, Ge-Juan; Lei, Hui; Di, Zheng-Li

2015-01-01

Homer is a family of post synaptic density proteins functionally and physically attached to target proteins at proline-rich sequences. Reducing Homer1b/c expression has been shown in previous studies to be protective against excitotoxic insults, implicating Homer1b/c in the physiological regulation of aberrant neuronal excitability. To test the efficacy of a Homer1b/c reducing therapy for disorders with a detrimental hyperexcitability profile in mice, we used small interfere RNA (siRNA) to decrease endogenous Homer1b/c expression in mouse hippocampus. The baseline motor and cognitive behavior was measured by sensorimotor tests, Morris water maze and elevated plus maze tasks. The anti-epileptic effects of Homer1b/c knockdown were determined in two chemically induced seizure models induced by Picrotoxin (PTX) or pentylenetetrazole (PTZ) administration. The results of sensorimotor tests, Morris water maze and elevated plus maze tasks showed that Homer1b/c reduction had no effect on baseline motor or cognitive behavior. In two chemically induced seizure models, mice with reduced Homerb/c protein had less severe seizures than control mice. Total Homer1b/c protein levels and seizure severity were highly correlated, such that those mice with the most severe seizures also had the highest levels of Homer1b/c. In addition, the phosphorylation of mammalian target of rapamycin (mTOR) and its target protein S6 was significantly inhibited in Homer1b/c down-regulated mice. Homer1b/c knockdown-induced inhibition of mTOR pathway was partially ablated by the metabotropic glutamate receptor 5 (mGluR5) agonist CHPG. Our results demonstrate that endogenous Homer1b/c is integral for regulating neuronal hyperexcitability in adult animals and suggest that reduction of Homer1b/c could protect against chemically induced seizures through inhibition mTOR pathway. © 2015 S. Karger AG, Basel.

Hydrogen peroxide toxicity induces Ras signaling in human neuroblastoma SH-SY5Y cultured cells.

PubMed

Chetsawang, Jirapa; Govitrapong, Piyarat; Chetsawang, Banthit

2010-01-01

It has been reported that overproduction of reactive oxygen species occurs after brain injury and mediates neuronal cells degeneration. In the present study, we examined the role of Ras signaling on hydrogen peroxide-induced neuronal cells degeneration in dopaminergic neuroblastoma SH-SY5Y cells. Hydrogen peroxide significantly reduced cell viability in SH-SY5Y cultured cells. An inhibitor of the enzyme that catalyzes the farnesylation of Ras proteins, FTI-277, and a competitive inhibitor of GTP-binding proteins, GDP-beta-S significantly decreased hydrogen peroxide-induced reduction in cell viability in SH-SY5Y cultured cells. The results of this study might indicate that a Ras-dependent signaling pathway plays a role in hydrogen peroxide-induced toxicity in neuronal cells.

Profiling the changes in signaling pathways in ascorbic acid/β-glycerophosphate-induced osteoblastic differentiation.

PubMed

Chaves Neto, Antonio Hernandes; Queiroz, Karla Cristiana; Milani, Renato; Paredes-Gamero, Edgar Julian; Justo, Giselle Zenker; Peppelenbosch, Maikel P; Ferreira, Carmen Veríssima

2011-01-01

Despite numerous reports on the ability of ascorbic acid and β-glycerophosphate (AA/β-GP) to induce osteoblast differentiation, little is known about the molecular mechanisms involved in this phenomenon. In this work, we used a peptide array containing specific consensus sequences (potential substrates) for protein kinases and traditional biochemical techniques to examine the signaling pathways modulated during AA/β-GP-induced osteoblast differentiation. The kinomic profile obtained after 7 days of treatment with AA/β-GP identified 18 kinase substrates with significantly enhanced or reduced phosphorylation. Peptide substrates for Akt, PI3K, PKC, BCR, ABL, PRKG1, PAK1, PAK2, ERK1, ERBB2, and SYK showed a considerable reduction in phosphorylation, whereas enhanced phosphorylation was observed in substrates for CHKB, CHKA, PKA, FAK, ATM, PKA, and VEGFR-1. These findings confirm the potential usefulness of peptide microarrays for identifying kinases known to be involved in bone development in vivo and in vitro and show that this technique can be used to investigate kinases whose function in osteoblastic differentiation is poorly understood.

Attenuation of cadmium-induced necrotic cell death by necrostatin-1: Potential necrostatin-1 acting sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, T.-S.; Yang, P.-M.; Tsai, J.-S.

2009-03-01

Cadmium (Cd) induces necrotic death in Chinese hamster ovary (CHO) K1 cells and we have established the responsible signaling pathway. Reportedly, necrostatin-1 (Nec-1) rescues cells from necrotic death by mediating through the death domain receptor (DR) signaling pathway. We show here that Nec-1 also effectively attenuates necrotic death triggered by Cd. Two other treatments that cause necrotic cell death, one can (z-VAD-fmk/TNF-{alpha} on U937 cells) and the other cannot (etherynic acid (EA) on DLD-1 cells) be rescued by Nec-1, were also studied in parallel for comparison. Results show that Nec-1 is ineffectual in modulating intracellular calcium contents, calpain activity (amore » downstream protease), or reactive oxygen species production. It can counteract the reduction in mitochondrial membrane potential (MMP) caused by treating CHO K1 or U937 cells with necrosis-inducing agent. However, this effect was not found in EA-treated DLD-1 cells. Notably, Nec-1 elevates NF-{kappa}B activity in the presence or absence of necrosis-inducing agents. Our study shows that, in addition to DR-mediated necrosis, Nec-1 is effective in attenuating Cd-induced necrosis. It rescues cells with reduced MMP implying that mitochondrion is its major acting site.« less

Carnosic acid protects SH-SY5Y cells against 6-hydroxydopamine-induced cell death through upregulation of parkin pathway.

PubMed

Lin, Chia-Yuan; Tsai, Chia-Wen; Tsai, Chia-Wen

2016-11-01

Parkin is a Parkinson's disease (PD)-linked gene that plays an important role in the ubiquitin-proteasome system (UPS). This study explored whether carnosic acid (CA) from rosemary protects against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity via upregulation of parkin in vivo and in vitro. We found that the reduction in proteasomal activity by 6-OHDA was attenuated in SH-SY5Y cells pretreated with 1 μM CA. Immunoblots showed that CA reversed the induction of ubiquitinated protein and the reduction of PTEN-induced putative kinase 1 (PINK1) and parkin protein in 6-OHDA-treated SH-SY5Y cells and rats. Moreover, in a transgenic OW13 Caenorhabditis elegans model of PD that expresses human α-synuclein in muscle cells, CA reduced α-synuclein accumulation in a dose-dependent manner. In cells pretreated with the proteasome inhibitor MG132, CA no longer reversed the 6-OHDA-mediated induction of cleavage of caspase 3 and poly(ADP)-ribose polymerase and no longer reversed the suppression of proteasome activity. When parkin expression was silenced by use of small interfering RNA, the ability of CA to inhibit apoptosis and induce proteasomal activity was significantly reduced. The reduction in 6-OHDA-induced neurotoxicity by CA was associated with the induction of parkin, which in turn upregulated the UPS and then decreased cell death. Copyright © 2016. Published by Elsevier Ltd.

Protocatechuic aldehyde ameliorates experimental pulmonary fibrosis by modulating HMGB1/RAGE pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Liang, E-mail: countryspring@sina.com; Ji, Yunxia, E-mail: 413499057@qq.com; Kang, Zechun, E-mail: davidjiangwl@163.com

An abnormal high mobility group box 1 (HMGB1) activation and a decrease in receptor for advanced glycation end-product (RAGE) play a key role in the pathogenesis of pulmonary fibrosis. Protocatechuic aldehyde (PA) is a naturally occurring compound, which is extracted from the degradation of phenolic acids. However, whether PA has anti-fibrotic functions is unknown. In this study, the effects of PA on the transforming growth factor-β1 (TGF-β1)-mediated epithelial–mesenchymal transition (EMT) in A549 cells, on the apoptosis of human type I alveolar epithelial cells (AT I), on the proliferation of human lung fibroblasts (HLF-1) in vitro, and on bleomycin (BLM)-induced pulmonarymore » fibrosis in vivo were investigated. PA treatment resulted in a reduction of EMT in A549 cells with a decrease in vimentin and HMGB, an increase of E-cadherin and RAGE, a reduction of HLF-1 proliferation with a decrease of fibroblast growth factor 2 (FGF-2) and platelet-derived growth factor (PDGF). Apoptosis of AT I was attenuated with an increase of RAGE. PA ameliorated BLM-induced pulmonary fibrosis in rats with a reduction of histopathological scores and collagen deposition, and a lower FGF-2, PDGF, α-smooth muscle actin (α-SMA) and HMGB1 expression, whereas higher RAGE was found in BLM-instilled lungs. Through the decrease of HGMB1 and the regulation of RAGE, PA reversed the EMT, inhibited HLF-1 proliferation as well as reduced apoptosis in AT I, and prevented pulmonary fibrosis in vivo. Collectively, our results demonstrate that PA prevents experimental pulmonary fibrosis by modulating HMGB1/RAGE pathway. - Highlights: • PA prevents EMT, reduces the apoptosis of AT1 in vitro. • PA decreases proliferation of HLF-1, reduces PDGF and FGF expression in vitro. • PA prevents experimental pulmonary fibrosis by modulating the HMGB1/RAGE pathway.« less

Rivastigmine for refractory REM behavior disorder in mild cognitive impairment.

PubMed

Brunetti, Valerio; Losurdo, Anna; Testani, Elisa; Lapenta, Leonardo; Mariotti, Paolo; Marra, Camillo; Rossini, Paolo Maria; Della Marca, Giacomo

2014-03-01

Mild Cognitive Impairment (MCI) and REM Behavior Disorder (RBD) are both associated with a degeneration of ponto-medullary cholinergic pathways. We conducted a placebo-controlled, cross-over pilot trial of Rivastigmine (RVT) in 25 consecutive patients with MCI, who presented RBD refractory to conventional first-line treatments (melatonin up to 5 mg/day and clonazepam up to 2 mg/day). RVT treatment was followed by a significant reduction of RBD episodes when compared with placebo. Our data suggest that, in MCI patients with RBD resistant to conventional therapies (muscle relaxants benzodiazepines or melatonin,) treatment with RVT may induce a reduction in the frequency of RBD episodes compared to placebo.

Vismodegib Suppresses TRAIL-mediated Liver Injury in a Mouse Model of Nonalcoholic Steatohepatitis

PubMed Central

Hirsova, Petra; Ibrahim, Samar H.; Bronk, Steven F.; Yagita, Hideo; Gores, Gregory J.

2013-01-01

Hedgehog signaling pathway activation has been implicated in the pathogenesis of NASH. Despite this concept, hedgehog pathway inhibitors have not been explored. Thus, we examined the effect of vismodegib, a hedgehog signaling pathway inhibitor, in a diet-induced model of NASH. C57BL/6 mice were placed on 3-month chow or FFC (high saturated fats, fructose, and cholesterol) diet. One week prior to sacrifice, mice were treated with vismodegib or vehicle. Mice fed the FFC diet developed significant steatosis, which was unchanged by vismodegib therapy. In contrast, vismodegib significantly attenuated FFC-induced liver injury as manifested by reduced serum ALT and hepatic TUNEL-positive cells. In line with the decreased apoptosis, vismodegib prevented FFC-induced strong upregulation of death receptor DR5 and its ligand TRAIL. In addition, FFC-fed mice, but not chow-fed animals, underwent significant liver injury and apoptosis following treatment with a DR5 agonist; however, this injury was prevented by pre-treatment with vismodegib. Consistent with a reduction in liver injury, vismodegib normalized FFC-induced markers of inflammation including mRNA for TNF-α, IL-1β, IL-6, monocyte chemotactic protein-1 and a variety of macrophage markers. Furthermore, vismodegib in FFC-fed mice abrogated indices of hepatic fibrogenesis. In conclusion, inhibition of hedgehog signaling with vismodegib appears to reduce TRAIL-mediated liver injury in a nutrient excess model of NASH, thereby attenuating hepatic inflammation and fibrosis. We speculate that hedgehog signaling inhibition may be salutary in human NASH. PMID:23894677

Characterization of the role of Fhit in maintenance of genomic integrity following low dose radiation, in vivo and in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ya Wang

2010-05-31

The major goal of this study is to determine the effects of the Fhit pathway on low dose ({le} 0.1 Gy) ionizing radiation (IR)-induced genetic instability. Reduction of Fhit protein expression is observed in most solid tumors particularly in those tumors resulting from exposure to environmental carcinogens. Therefore, characterization of the role of the Fhit-dependent pathway in preventing low dose IR-induced genetic instability will provide useful parameters for evaluating the low dose IR-induced risk of mutagenesis and carcinogenesis. We pursued 3 specific aims to study our hypothesis that the Fhit-dependent pathways maintain genomic integrity through adjusting checkpoint response and repairmore » genes expression following low dose IR. Aim 1: Determine whether Fhit interaction with RPA is necessary for Fhit to affect the cellular response to low dose IR. We combined the approaches of in vitro (GST pull-down and site-directed mutagenesis) and in vivo (observing the co-localization and immunoprecipitation of Fhit and RPA in Fhit knock out mouse cells transfected with mutant Fhit which has lost ability to interact with RPA in vitro). Aim 2: Determine the role of genes whose expression is affected by Fhit in low dose irradiated cells. We analyzed the distinct signature of gene expression in low dose irradiated Fhit-/- cells compared with Fhit+/+ cells by combining microarray, gene transfection and siRNA approaches. Aim 3: Determine the role of Fhit in genetic susceptibility to low dose IR in vivo. We compared the gene mutation frequency and the fragile site stability in the cells isolated from the Fhit+/+ and Fhit-/- mice at 1.5 years following low dose IR. These results determine the role of the Fhit-dependent pathway in maintaining genomic integrity in vitro and in vivo, which provide a basis for choosing surrogate markers in the Fhit-dependent pathway to evaluate low dose IR-induced risk of mutagenesis and carcinogenesis.« less

Modulation of intestinal sulfur assimilation metabolism regulates iron homeostasis

PubMed Central

Hudson, Benjamin H.; Hale, Andrew T.; Irving, Ryan P.; Li, Shenglan; York, John D.

2018-01-01

Sulfur assimilation is an evolutionarily conserved pathway that plays an essential role in cellular and metabolic processes, including sulfation, amino acid biosynthesis, and organismal development. We report that loss of a key enzymatic component of the pathway, bisphosphate 3′-nucleotidase (Bpnt1), in mice, both whole animal and intestine-specific, leads to iron-deficiency anemia. Analysis of mutant enterocytes demonstrates that modulation of their substrate 3′-phosphoadenosine 5′-phosphate (PAP) influences levels of key iron homeostasis factors involved in dietary iron reduction, import and transport, that in part mimic those reported for the loss of hypoxic-induced transcription factor, HIF-2α. Our studies define a genetic basis for iron-deficiency anemia, a molecular approach for rescuing loss of nucleotidase function, and an unanticipated link between nucleotide hydrolysis in the sulfur assimilation pathway and iron homeostasis. PMID:29507250

A Tolerant Behavior in Salt-Sensitive Tomato Plants can be Mimicked by Chemical Stimuli

PubMed Central

Flors, Víctor; Paradís, Mercedes; García-Andrade, Javier; Cerezo, Miguel; González-Bosch, Carmen

2007-01-01

Lycopersicon esculentum plants exhibit increased salt stress tolerance following treatment with adipic acid monoethylester and 1,3-diaminepropane (DAAME), known as an inducer of resistance against biotic stress in tomato and pepper. For an efficient water and nutrient uptake, plants should adapt their water potential to compensate a decrease in water soil potential produced by salt stress. DAAME-treated plants showed a faster and stronger water potential reduction and an enhanced proline accumulation. Salinity-induced oxidative stress was also ameliorated by DAAME treatments. Oxidative membrane damage and ethylene emission were both reduced in DAAME-treated plants. This effect is probably a consequence of an increase of both non-enzymatic antioxidant activity as well as peroxidase activity. DAAME-mediated tolerance resulted in an unaltered photosynthetic rate and a stimulation of the decrease in transpiration under stress conditions without a cost in growth due to salt stress. The reduction in transpiration rate was concomitant with a reduction in phytotoxic Na+ and Cl− accumulation under saline stress. Interestingly, the ABA deficient tomato mutant sitiens was insensitive to DAAME-induced tolerance following NaCl stress exposure. Additionally, DAAME treatments increased the ABA content of leaves, therefore, an intact ABA signalling pathway seems to be important to express DAAME-induced salt tolerance. Here, we show a possibility of enhance tomato stress tolerance by chemical induction of the major plant defences against salt stress. DAAME-induced tolerance against salt stress could be complementary to or share elements with induced resistance against biotic stress. This might be the reason for the observed wide spectrum of effectiveness of this compound. PMID:19516968

Disruption of nucleotide excision repair by the human T-cell leukemia virus type 1 Tax protein.

PubMed

Kao, S Y; Marriott, S J

1999-05-01

The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is a transcriptional transactivator and viral oncogene. Since cellular transformation has been frequently linked to alterations in genome stability, we investigated the effect of Tax on nucleotide excision repair (NER), a prominent cellular DNA repair pathway. Cells expressing Tax exhibited a reduced capacity for NER as measured by unscheduled DNA synthesis and host cell reactivation assays. The cellular proliferating cell nuclear antigen (PCNA) gene product regulates DNA replication and repair pathways, including NER. Since Tax activates transcription of the PCNA promoter, we investigated whether this activity contributes to the reduction of NER. Tax increased endogenous PCNA protein expression, and analysis of Tax mutant proteins demonstrated that the reduction in NER correlated with Tax transactivation of PCNA gene expression. Direct overexpression of PCNA also reduced NER. We propose that overexpression of PCNA, and disruption of NER induced by Tax, predisposes cells to accumulate DNA damage and contributes to HTLV-1 transformation.

Reduction of apoptosis through the mitochondrial pathway by the administration of acetyl-L-carnitine to mouse fibroblasts in culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pillich, Rudolf Tito; Dipartimento di Genetica e Biologia Molecolare, Universita di Roma 'La Sapienza', P.le A. Moro, 5-00185 Rome; Scarsella, Gianfranco

It is shown in literature that stress, such as deprivation of trophic factors and hypoxia, induces apoptosis in cultured cells and in tissues. In light of these results, we explored the possibility of protecting cells from programmed death by improving the metabolism of the mitochondrion. To this end, acetyl-L-carnitine was administered at various concentrations under conditions of serum deprivation. The choice of this drug was based on the accepted notion that acetyl-L-carnitine is able to stabilize mitochondrial membranes and to increase the supply of energy to the organelle. The results presented here indicate that the drug protects cells from apoptoticmore » death: this is demonstrated by a lower positivity to the TUNEL reaction and by a strong reduction of the apoptotic DNA ladder in serum-deprived cells. The involvement of the mitochondrial apoptotic pathway was assessed by cytochrome C release and immunoreactivity to caspase 3. Moreover, acetyl-L-carnitine stimulates cell proliferation.« less

Nickel (II)-induced cytotoxicity and apoptosis in human proximal tubule cells through a ROS- and mitochondria-mediated pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yi-Fen; Shyu, Huey-Wen; Chang, Yi-Chuang

2012-03-01

Nickel compounds are known to be toxic and carcinogenic in kidney and lung. In this present study, we investigated the roles of reactive oxygen species (ROS) and mitochondria in nickel (II) acetate-induced cytotoxicity and apoptosis in the HK-2 human renal cell line. The results showed that the cytotoxic effects of nickel (II) involved significant cell death and DNA damage. Nickel (II) increased the generation of ROS and induced a noticeable reduction of mitochondrial membrane potential (MMP). Analysis of the sub-G1 phase showed a significant increase in apoptosis in HK-2 cells after nickel (II) treatment. Pretreatment with N-acetylcysteine (NAC) not onlymore » inhibited nickel (II)-induced cell death and DNA damage, but also significantly prevented nickel (II)-induced loss of MMP and apoptosis. Cell apoptosis triggered by nickel (II) was characterized by the reduced protein expression of Bcl-2 and Bcl-xL and the induced the protein expression of Bad, Bcl-Xs, Bax, cytochrome c and caspases 9, 3 and 6. The regulation of the expression of Bcl-2-family proteins, the release of cytochrome c and the activation of caspases 9, 3 and 6 were inhibited in the presence of NAC. These results suggest that nickel (II) induces cytotoxicity and apoptosis in HK-2 cells via ROS generation and that the mitochondria-mediated apoptotic signaling pathway may be involved in the positive regulation of nickel (II)-induced renal cytotoxicity.« less

Protection of acetaminophen induced mitochondrial dysfunctions and hepatic necrosis via Akt-NF-kappaB pathway: role of a novel plant protein.

PubMed

Ghosh, Ayantika; Sil, Parames C

2009-01-27

Oxidative stress is a major cause of drug induced hepatic diseases. The present study aims to investigate the antioxidative signaling mechanism of a protein isolated from the herb, Cajanus indicus against acetaminophen induced necrotic cell death. We found that incubation of hepatocytes with the protein prevented acetaminophen-induced loss in cell viability, reduction in glutathione level and enhancement of reactive oxygen species generation. Treatment of mice with the protein before administration of acetaminophen also reduced serum nitrite and TNF-alpha formation. Moreover, it counteracted acetaminophen-induced loss in mitochondrial membrane potential, loss in adenosine tri phosphate and rise in intracellular calcium. Investigating the cell signaling pathways, we found that the protein exerts its protective action via the activation of NF-kappaB and Akt and deactivation of STAT-1. Surprisingly, no role of ERK1/2 or STAT-3 was found in the protein-mediated protection of hepatocytes during acetaminophen exposure. Finally, we found that acetaminophen introduces necrosis as the primary phenomena of cell death and protein treatment decreased the necrotic process as evident from the DNA fragmentation and flow-cytometry studies. In addition, administration of the protein to mice before acetaminophen application showed fewer number of TUNEL positive cells. Combining, data suggest that the protein possesses cytoprotective activity against acetaminophen-induced oxidative cellular damage and prevents hepatocytes from necrotic death.

Resveratrol Ameliorates Microcystin-LR-Induced Testis Germ Cell Apoptosis in Rats via SIRT1 Signaling Pathway Activation.

PubMed

Liu, Haohao; Zhang, Shenshen; Liu, Chuanrui; Wu, Jinxia; Wang, Yueqin; Yuan, Le; Du, Xingde; Wang, Rui; Marwa, Phelisters Wegesa; Zhuang, Donggang; Cheng, Xuemin; Zhang, Huizhen

2018-06-09

Microcystin-leucine arginine (MC-LR), a cyclic heptapeptide produced by cyanobacteria, is a strong reproductive toxin. Studies performed in rat Sertoli cells and Chinese hamster ovary cells have demonstrated typical apoptosis after MC-LR exposure. However, little is known on how to protect against the reproductive toxicity induced by MC-LR. The present study aimed to explore the possible molecular mechanism underlying the anti-apoptosis and protective effects of resveratrol (RES) on the co-culture of Sertoli⁻germ cells and rat testes. The results demonstrated that MC-LR treatment inhibited the proliferation of Sertoli⁻germ cells and induced apoptosis. Furthermore, sirtuin 1 (SIRT1) and Bcl-2 were inhibited, while p53 and Ku70 acetylation, Bax expression, and cleaved caspase-3 were upregulated by MC-LR. However, RES pretreatment ameliorated MC-LR-induced apoptosis and SIRT1 inhibition, and downregulated the MC-LR-induced increase in p53 and Ku70 acetylation, Bax expression, and caspase-3 activation. In addition, RES reversed the MC-LR-mediated reduction in Ku70 binding to Bax. The present study indicated that the administration of RES could ameliorate MC-LR-induced Sertoli⁻germ cell apoptosis and protect against reproductive toxicity in rats by stimulating the SIRT1/p53 pathway, suppressing p53 and Ku70 acetylation and enhancing the binding of Ku70 to Bax.

Protective effect of salidroside against bone loss via hypoxia-inducible factor-1α pathway-induced angiogenesis

PubMed Central

Li, Ling; Qu, Ye; Jin, Xin; Guo, Xiao Qin; Wang, Yue; Qi, Lin; Yang, Jing; Zhang, Peng; Li, Ling Zhi

2016-01-01

Hypoxia-inducible factor (HIF)-1α plays a critical role in coupling angiogenesis with osteogenesis during bone development and regeneration. Salidroside (SAL) has shown anti-hypoxic effects in vitro and in vivo. However, the possible roles of SAL in the prevention of hypoxia-induced osteoporosis have remained unknown. Two osteoblast cell lines, MG-63 and ROB, were employed to evaluate the effects of SAL on cell viability, apoptosis, differentiation and mineralization in vitro. Rats subjected to ovariectomy-induced bone loss were treated with SAL in vivo. Our results showed that pre-treatment with SAL markedly attenuated the hypoxia-induced reductions in cell viability, apoptosis, differentiation and mineralization. SAL down-regulated HIF-1α expression and inhibited its translocation; however, SAL increased its transcriptional activity and, consequently, up-regulated vascular endothelial growth factor (VEGF). In vivo studies further demonstrated that SAL caused decreases in the mineral, alkaline phosphatase (ALP), and BGP concentrations in the blood of ovariectomized (OVX) rats. Moreover, SAL improved the trabecular bone microarchitecture and increased bone mineral density in the distal femur. Additionally, SAL administration partially ameliorated this hypoxia via the HIF-1α-VEGF signalling pathway. Our results indicate that SAL prevents bone loss by enhancing angiogenesis and osteogenesis and that these effects are associated with the activation of HIF-1α signalling. PMID:27558909

RANKL downregulates cell surface CXCR6 expression through JAK2/STAT3 signaling pathway during osteoclastogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Changhong; Zhao, Jinxia; Sun, Lin

Highlights: Black-Right-Pointing-Pointer CXCR6 is down-regulated during RANKL-induced osteoclastogenesis in RAW264.7 cells. Black-Right-Pointing-Pointer CXCR6 reduction was nearly reversed by inhibition of JAK2/STAT3 signaling pathway. Black-Right-Pointing-Pointer CXCL16 alone does not positively regulate osteoclastogenesis. -- Abstract: The receptor activator of nuclear factor-{kappa}B ligand (RANKL), as a member of the tumor necrosis factor (TNF) family, plays an essential role in osteoclast differentiation and function. Chemokines and their receptors have recently been shown to play critical roles in osteoclastogenesis, however, whether CXCL16-CXCR6 plays role in RANKL-mediated osteoclastogenesis is unknown. In this study, we first reported that RANKL decreased CXCR6 in a dose-dependent manner, which maymore » be through deactivation of Akt and STAT3 signaling induced by CXCL16. Interestingly, RANKL-mediated CXCR6 reduction may be associated to the activation of STAT3 by phosphorylation. When STAT3 activation was blocked by JAK2/STAT3 inhibitor AG490, RANKL failed to shut down CXCR6 expression during osteoclastogenesis. However, CXCL16 alone did not augment RANKL-mediated osteoclast differentiation and did not alter RANKL-receptor RANK mRNA expression. These results demonstrate that reduction of CXCL16-CXCR6 is critical in RANKL-mediated osteoclastogenesis, which is mainly through the activation of JAK2/STAT3 signaling. CXCL16-CXCR6 axis may become a novel target for the therapeutic intervention of bone resorbing diseases such as rheumatoid arthritis and osteoporosis.« less

Virus-induced gene silencing of Withania somnifera squalene synthase negatively regulates sterol and defence-related genes resulting in reduced withanolides and biotic stress tolerance.

PubMed

Singh, Anup Kumar; Dwivedi, Varun; Rai, Avanish; Pal, Shaifali; Reddy, Sajjalavarahalli Gangireddy Eswara; Rao, Dodaghatta Krishnarao Venkata; Shasany, Ajit Kumar; Nagegowda, Dinesh A

2015-12-01

Withania somnifera (L.) Dunal is an important Indian medicinal plant that produces withanolides, which are triterpenoid steroidal lactones having diverse biological activities. To enable fast and efficient functional characterization of genes in this slow-growing and difficult-to-transform plant, a virus-induced gene silencing (VIGS) was established by silencing phytoene desaturase (PDS) and squalene synthase (SQS). VIGS of the gene encoding SQS, which provides precursors for triterpenoids, resulted in significant reduction of squalene and withanolides, demonstrating its application in studying withanolides biosynthesis in W. somnifera leaves. A comprehensive analysis of gene expression and sterol pathway intermediates in WsSQS-vigs plants revealed transcriptional modulation with positive feedback regulation of mevalonate pathway genes, and negative feed-forward regulation of downstream sterol pathway genes including DWF1 (delta-24-sterol reductase) and CYP710A1 (C-22-sterol desaturase), resulting in significant reduction of sitosterol, campesterol and stigmasterol. However, there was little effect of SQS silencing on cholesterol, indicating the contribution of sitosterol, campesterol and stigmasterol, but not of cholesterol, towards withanolides formation. Branch-point oxidosqualene synthases in WsSQS-vigs plants exhibited differential regulation with reduced CAS (cycloartenol synthase) and cycloartenol, and induced BAS (β-amyrin synthase) and β-amyrin. Moreover, SQS silencing also led to the down-regulation of brassinosteroid-6-oxidase-2 (BR6OX2), pathogenesis-related (PR) and nonexpressor of PR (NPR) genes, resulting in reduced tolerance to bacterial and fungal infection as well as to insect feeding. Taken together, SQS silencing negatively regulated sterol and defence-related genes leading to reduced phytosterols, withanolides and biotic stress tolerance, thus implicating the application of VIGS for functional analysis of genes related to withanolides formation in W. somnifera leaves. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Effects of novel muscarinic M3 receptor ligand C1213 in pulmonary arterial hypertension models.

PubMed

Ahmed, Mohamed; VanPatten, Sonya; Lakshminrusimha, Satyan; Patel, Hardik; Coleman, Thomas R; Al-Abed, Yousef

2016-12-01

Pulmonary hypertension (PH) is a complex disease comprising a pathologic remodeling and thickening of the pulmonary vessels causing an after load on the right heart ventricle that can result in ventricular failure. Triggered by oxidative stress, episodes of hypoxia, and other undetermined causes, PH is associated with poor outcomes and a high rate of morbidity. In the neonate, this disease has a similar etiology but is further complicated by the transition to breathing after birth, which requires a reduction in vascular resistance. Persistent pulmonary hypertension of the newborn (PPHN) is one form of PH that is frequently unresponsive to current therapies including inhaled nitric oxide (due to lack of proper absorption and diffusion), and other therapeutics targeting signaling mediators in vascular endothelium and smooth muscle. The need for novel agents, which target distinct pathways in pulmonary hypertension, remains. Herein, we investigated the therapeutic effects of novel muscarinic receptor ligand C1213 in models of PH We demonstrated that via M3 muscarinic receptors, C1213 induced activating- eNOS phosphorylation (serine-1177), which is known to lead to nitric oxide (NO) production in endothelial cells. Using signaling pathway inhibitors, we discovered that AKT and calcium signaling contributed to eNOS phosphorylation induced by C1213. As expected for an eNOS-stimulating agent, in ex vivo and in vivo models, C1213 triggered pulmonary vasodilation and induced both pulmonary artery and systemic blood pressure reductions demonstrating its potential value in PH and PPHN In brief, this proof-of-concept study provides evidence that an M3 muscarinic receptor functionally selective ligand stimulates downstream pathways leading to antihypertensive effects using in vitro, ex vivo, and in vivo models of PH. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Photo-illuminated diamond as a solid-state source of solvated electrons in water for nitrogen reduction.

PubMed

Zhu, Di; Zhang, Linghong; Ruther, Rose E; Hamers, Robert J

2013-09-01

The photocatalytic reduction of N₂ to NH₃ is typically hampered by poor binding of N₂ to catalytic materials and by the very high energy of the intermediates involved in this reaction. Solvated electrons directly introduced into the reactant solution can provide an alternative pathway to overcome such limitations. Here we demonstrate that illuminated hydrogen-terminated diamond yields facile electron emission into water, thus inducing reduction of N₂ to NH₃ at ambient temperature and pressure. Transient absorption measurements at 632 nm reveal the presence of solvated electrons adjacent to the diamond after photoexcitation. Experiments using inexpensive synthetic diamond samples and diamond powder show that photocatalytic activity is strongly dependent on the surface termination and correlates with the production of solvated electrons. The use of diamond to eject electrons into a reactant liquid represents a new paradigm for photocatalytic reduction, bringing electrons directly to reactants without requiring molecular adsorption to the surface.

Mitochondrial ROS Induces Cardiac Inflammation via a Pathway through mtDNA Damage in a Pneumonia-Related Sepsis Model.

PubMed

Yao, Xiao; Carlson, Deborah; Sun, Yuxiao; Ma, Lisha; Wolf, Steven E; Minei, Joseph P; Zang, Qun S

2015-01-01

We have previously shown that mitochondria-targeted vitamin E (Mito-Vit-E), a mtROS specific antioxidant, improves cardiac performance and attenuates inflammation in a pneumonia-related sepsis model. In this study, we applied the same approaches to decipher the signaling pathway(s) of mtROS-dependent cardiac inflammation after sepsis. Sepsis was induced in Sprague Dawley rats by intratracheal injection of S. pneumoniae. Mito-Vit-E, vitamin E or vehicle was administered 30 minutes later. In myocardium 24 hours post-inoculation, Mito-Vit-E, but not vitamin E, significantly protected mtDNA integrity and decreased mtDNA damage. Mito-Vit-E alleviated sepsis-induced reduction in mitochondria-localized DNA repair enzymes including DNA polymerase γ, AP endonuclease, 8-oxoguanine glycosylase, and uracil-DNA glycosylase. Mito-Vit-E dramatically improved metabolism and membrane integrity in mitochondria, suppressed leakage of mtDNA into the cytoplasm, inhibited up-regulation of Toll-like receptor 9 (TLR9) pathway factors MYD88 and RAGE, and limited RAGE interaction with its ligand TFAM in septic hearts. Mito-Vit-E also deactivated NF-κB and caspase 1, reduced expression of the essential inflammasome component ASC, and decreased inflammatory cytokine IL-1β. In vitro, both Mito-Vit-E and TLR9 inhibitor OND-I suppressed LPS-induced up-regulation in MYD88, RAGE, ASC, active caspase 1, and IL-1β in cardiomyocytes. Since free mtDNA escaped from damaged mitochondria function as a type of DAMPs to stimulate inflammation through TLR9, these data together suggest that sepsis-induced cardiac inflammation is mediated, at least partially, through mtDNA-TLR9-RAGE. At last, Mito-Vit-E reduced the circulation of myocardial injury marker troponin-I, diminished apoptosis and amended morphology in septic hearts, suggesting that mitochondria-targeted antioxidants are a potential cardioprotective approach for sepsis.

Attenuation of inflammatory response by a novel chalcone protects kidney and heart from hyperglycemia-induced injuries in type 1 diabetic mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Qilu; Diabetes Center and Department of Endocrinology, the Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang; Wang, Jingying

High glucose-induced inflammatory response in diabetic complications plays an important role in disease occurrence and development. With inflammatory cytokines and signaling pathways as important mediators, targeting inflammation may be a new avenue for treating diabetic complications. Chalcones are a class of natural products with various pharmacological activities. Previously, we identified L2H17 as a chalcone with good anti-inflammatory activity, inhibiting LPS-induced inflammatory response in macrophages. In this study, we examined L2H17's effect on hyperglycemia-induced inflammation both in mouse peritoneal macrophages and a streptozotocin-induced T1D mouse model. Our results indicate that L2H17 exhibits a strong inhibitory effect on the expression of pro-inflammatorymore » cytokines, cell adhesion molecules, chemokines and macrophage adhesion via modulation of the MAPK/NF-κB pathway. Furthermore, in vivo oral administration of L2H17 resulted in a significant decrease in the expression of pro-inflammatory cytokines and cell adhesion molecules, contributing to a reduction of key markers for renal and cardiac dysfunction and improvements in fibrosis and pathological changes in both renal and cardiac tissues of diabetic mice. These findings provide the evidence supporting targeting MAPK/NF-κB pathway may be effective therapeutic strategy for diabetic complications, and suggest that L2H17 may be a promising anti-inflammatory agent with potential as a therapeutic agent in the treatment of renal and cardiac diabetic complications. - Highlights: • Chalcones are a class of natural products with various pharmacological activities. • We identified L2H17 a chalcone with good anti-inflammatory activity. • L2H17 improved histological abnormalities both in diabetic heart and kidney. • L2H17 reduced inflammatory responses in HG-stimulated mouse peritoneal macrophages. • MAPKs/NF-κB pathway may be a promising therapeutic target for diabetic complications.« less

Curcumin reverses attenuated carbachol-induced contraction of the colon in a rat model of colitis.

PubMed

Lubbad, Asmaa S; Oriowo, Mabayoje A; Khan, Islam

2009-01-01

Curcumin ameliorates colitis whether it reverses colitis-induced reduction in colonic contractility remains to be investigated. To investigate the effect of curcumin on colitis-induced reduction of carbachol-induced contraction in colon segments from rats treated with trinitrobenzenesulphonic acid. Colitis was induced in rats by intra rectal administration of trinitrobenzenesulphonic acid and followed for 5 days. A group of animals which received trinitobenzene sulphonic acids was treated with curcumin (100 mg/Kg and 200 mg/kg body weight) 2 hrs prior to induction of colitis. The controls received phosphate buffered saline in a similar fashion. Markers of inflammation and contractility of colon were assayed using standard procedures. Induction of colitis was associated with increased myeloperoxidase activity and malondialdehyde levels, gross histological changes characterized by infiltration of inflammatory cells. All these changes were prevented by treatment with curcumin (100 mg/kg). Treatment with curcumin also reduced the histological scores from 3.34+/-0.40 to 1.75+/-0.30 confirming an anti-inflammatory effect of curcumin in this experimental model of colitis. Colonic reactivity to carbachol was decreased in colitis affecting the maximum response but not sensitivity. Treatment with curcumin had no effect on sensitivity of the colon to carbachol in any of the preparations. Curcumin however reversed the decrease in carbachol-induced contraction associated with trinitrobenzenesulphonic acid treatment. The same dose of curcumin had no effect on either the potency of or the maximum response to carbachol in control rats. Tissue expression of NF-kB was increased in colon segments from trinitrobenzenesulphonic acid -treated rats and this was inhibited in rats treated with curcumin. Based on these findings it is concluded that curcumin prevented the reduction in carbachol-induced contraction in trinitrobenzenesulphonic acid -treated rats by modulating NF-kB signaling pathway.

2-Deoxy-D-glucose treatment induces ketogenesis, sustains mitochondrial function, and reduces pathology in female mouse model of Alzheimer's disease.

PubMed

Yao, Jia; Chen, Shuhua; Mao, Zisu; Cadenas, Enrique; Brinton, Roberta Diaz

2011-01-01

Previously, we demonstrated that mitochondrial bioenergetic deficits preceded Alzheimer's disease (AD) pathology in the female triple-transgenic AD (3xTgAD) mouse model. In parallel, 3xTgAD mice exhibited elevated expression of ketogenic markers, indicating a compensatory mechanism for energy production in brain. This compensatory response to generate an alternative fuel source was temporary and diminished with disease progression. To determine whether this compensatory alternative fuel system could be sustained, we investigated the impact of 2-deoxy-D-glucose (2-DG), a compound known to induce ketogenesis, on bioenergetic function and AD pathology burden in brain. 6-month-old female 3xTgAD mice were fed either a regular diet (AIN-93G) or a diet containing 0.04% 2-DG for 7 weeks. 2-DG diet significantly increased serum ketone body level and brain expression of enzymes required for ketone body metabolism. The 2-DG-induced maintenance of mitochondrial bioenergetics was paralleled by simultaneous reduction in oxidative stress. Further, 2-DG treated mice exhibited a significant reduction of both amyloid precursor protein (APP) and amyloid beta (Aβ) oligomers, which was paralleled by significantly increased α-secretase and decreased γ-secretase expression, indicating that 2-DG induced a shift towards a non-amyloidogenic pathway. In addition, 2-DG increased expression of genes involved in Aβ clearance pathways, degradation, sequestering, and transport. Concomitant with increased bioenergetic capacity and reduced β-amyloid burden, 2-DG significantly increased expression of neurotrophic growth factors, BDNF and NGF. Results of these analyses demonstrate that dietary 2-DG treatment increased ketogenesis and ketone metabolism, enhanced mitochondrial bioenergetic capacity, reduced β-amyloid generation and increased mechanisms of β-amyloid clearance. Further, these data link bioenergetic capacity with β-amyloid generation and demonstrate that β-amyloid burden was dynamic and reversible, as 2-DG reduced activation of the amyloidogenic pathway and increased mechanisms of β-amyloid clearance. Collectively, these data provide preclinical evidence for dietary 2-DG as a disease-modifying intervention to delay progression of bioenergetic deficits in brain and associated β-amyloid burden.

Adaptive responses induced by 24S-hydroxycholesterol through liver X receptor pathway reduce 7-ketocholesterol-caused neuronal cell death☆

PubMed Central

Okabe, Akishi; Urano, Yasuomi; Itoh, Sayoko; Suda, Naoto; Kotani, Rina; Nishimura, Yuki; Saito, Yoshiro; Noguchi, Noriko

2013-01-01

Lipid peroxidation products have been known to induce cellular adaptive responses and enhance tolerance against subsequent oxidative stress through up-regulation of antioxidant compounds and enzymes. 24S-hydroxycholesterol (24SOHC) which is endogenously produced oxysterol in the brain plays an important role in maintaining brain cholesterol homeostasis. In this study, we evaluated adaptive responses induced by brain-specific oxysterol 24SOHC in human neuroblastoma SH-SY5Y cells. Cells treated with 24SOHC at sub-lethal concentrations showed significant reduction in cell death induced by subsequent treatment with 7-ketocholesterol (7KC) in both undifferentiated and retinoic acid-differentiated SH-SY5Y cells. These adaptive responses were also induced by other oxysterols such as 25-hydroxycholesterol and 27-hydroxycholesterol which are known to be ligands of liver X receptor (LXR). Co-treatment of 24SOHC with 9-cis retinoic acid, a retinoid X receptor ligand, enhanced the adaptive responses. Knockdown of LXRβ by siRNA diminished the adaptive responses induced by 24SOHC almost completely. The treatment with 24SOHC induced the expression of LXR target genes, such as ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1). The 24SOHC-induced adaptive responses were significantly attenuated by siRNA for ABCG1 but not by siRNA for ABCA1. Taken together, these results strongly suggest that 24SOHC at sub-lethal concentrations induces adaptive responses via transcriptional activation of LXR signaling pathway, thereby protecting neuronal cells from subsequent 7KC-induced cytotoxicity. PMID:24371802

Role of miR-155 in fluorooctane sulfonate-induced oxidative hepatic damage via the Nrf2-dependent pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, Chong; Han, Rui; Liu, Limin

Studies demonstrated that perfluorooctane sulfonate (PFOS) tends to accumulate in the liver and is capable to cause hepatomegaly. In the present study, we investigated the roles of miR-155 in PFOS-induced hepatotoxicity in SD rats and HepG2 cells. Male SD rats were orally administrated with PFOS at 1 or 10 mg/kg/day for 28 days while HepG2 cells were treated with 0–50 μM of PFOS for 24 h or 50 μM of PFOS for 1, 3, 6, 12 or 24 h, respectively. We found that PFOS significantly increased the liver weight and serum alanine transaminase (ALT) and aspartate amino transferase (AST) levelsmore » in rats. Morphologically, PFOS caused actin filament remodeling and endothelial permeability changes in the liver. Moreover, PFOS triggered reactive oxygen species (ROS) generation and induced apoptosis in both in vivo and in vitro assays. Immunoblotting data showed that NF-E2-related factor-2 (Nrf2) expression and activation and its target genes were all suppressed by PFOS in the liver and HepG2 cells. However, PFOS significantly increased miR-155 expression. Further studies showed that pretreatment of HepG2 cells with catalase significantly decreased miR-155 expression and substantially increased Nrf2 expression and activation, resulting in reduction of PFOS-induced cytotoxicity and oxidative stress. Taken together, these results indicated that miR-155 plays an important role in the PFOS-induced hepatotoxicity by disrupting Nrf2/ARE signaling pathway. - Highlights: • PFOS is capable to cause hepatotoxicity. • PFOS triggers ROS generation and induces apoptosis both in vivo and in vitro assays. • PFOS-induced ROS inhibits Nrf2 expression and its transactivation function. • PFOS promotes miR155 expression in liver and HepG2 cells. • miR-155 is involved in PFOS-induced hepatotoxicity by disrupting Nrf2/ARE pathway.« less

Peroxiredoxin 2 regulates PGF2α-induced corpus luteum regression in mice by inhibiting ROS-dependent JNK activation.

PubMed

Park, Sun-Ji; Kim, Jung-Hak; Kim, Tae-Shin; Lee, Sang-Rae; Park, Jeen-Woo; Lee, Seunghoon; Kim, Jin-Man; Lee, Dong-Seok

2017-07-01

Luteal regression is a natural and necessary event to regulate the reproductive process in all mammals. Prostaglandin F2α (PGF2α) is the main factor that causes functional and structural regression of the corpus luteum (CL). It is well known that PGF2α-mediated ROS generation is closely involved in luteal regression. Peroxiredoxin 2 (Prx2) as an antioxidant enzyme plays a protective role against oxidative stress-induced cell death. However, the effect of Prx2 on PGF2α-induced luteal regression has not been reported. Here, we investigated the role of Prx2 in functional and structural CL regression induced by PGF2α-mediated ROS using Prx2-deficient (-/-) mice. We found that PGF2α-induced ROS generation was significantly higher in Prx2-/- MEF cells compared with that in wild-type (WT) cells, which induced apoptosis by activating JNK-mediated apoptotic signaling pathway. Also, PGF2α treatment in the CL derived from Prx2-/- mice promoted the reduction of steroidogenic enzyme expression and the activation of JNK and caspase3. Compared to WT mice, serum progesterone levels and luteal expression of steroidogenic enzymes decreased more rapidly whereas JNK and caspase3 activations were significantly increased in Prx2-/- mice injected with PGF2α. However, the impaired steroidogenesis and PGF2α-induced JNK-dependent apoptosis were rescued by the addition of the antioxidant N-acetyl-L-cysteine (NAC). This is the first study to demonstrate that Prx2 deficiency ultimately accelerated the PGF2α-induced luteal regression through activation of the ROS-dependent JNK pathway. These findings suggest that Prx2 plays a crucial role in preventing accelerated luteal regression via inhibition of the ROS/JNK pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-angiogenic and anti-inflammatory effect of Magnolol in the oxygen-induced retinopathy model.

PubMed

Yang, Boyu; Xu, Yue; Yu, Shanshan; Huang, Yongsheng; Lu, Lin; Liang, Xiaoling

2016-01-01

In the present study, we investigated the effects of Magnolol on the retinal neovascularization (RNV) and local glial cells in an oxygen-induced retinopathy (OIR) model and explored their molecular mechanisms. Neonatal C57BL/6J mice were subjected to 75% O2 ± 5% from postnatal day (P) 7 to P12 and subsequently returned to room air. Mice were injected with 25 mg/kg Magnolol intraperitoneally once a day from P12 to P17, then retinas were harvested and flat-mounted to assess the retinal vessels, astrocytes and microglia. To clarify the molecular mechanisms of Magnolol, we observed the level of inflammatory cytokines such as interleukin (IL)-1β, IL-6, monocyte chemoattractant protein-1, tumor necrosis factor-α, and analyzed the hypoxia-inducible factor (HIF)-1α/vascular endothelial growth factor (VEGF) pathway in OIR mice. Intraperitoneal administration of Magnolol resulted in significant reduction of RNV without retinal toxicity or perturbation of developmental retinal angiogenesis. In addition, Magnolol preserved the astrocyte morphology and diminished the activation of microglia. Moreover, Magnolol down regulated the expression of inflammatory cytokines and inactivated the HIF-1α/VEGF pathway. These results indicated that Magnolol might have potential for the treatment of pathological retinal angiogenesis and glial dysfunctions via anti-inflammation and inhibition of HIF-1α/VEGF pathway.

Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice

PubMed Central

Liu, Xiao-Long; Luo, Liu; Mu, Rong-Hao; Liu, Bin-Bin; Geng, Di; Liu, Qing; Yi, Li-Tao

2015-01-01

Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus. PMID:26522512

Cholesterol Regulates μ-Opioid Receptor-Induced β-Arrestin 2 Translocation to Membrane Lipid RaftsS⃞

PubMed Central

Qiu, Yu; Wang, Yan; Chen, Hong-Zhuan; Loh, Horace H.

2011-01-01

μ-Opioid receptor (OPRM1) is mainly localized in lipid raft microdomains but internalizes through clathrin-dependent pathways. Our previous studies demonstrated that disruption of lipid rafts by cholesterol-depletion reagent blocked the agonist-induced internalization of OPRM1 and G protein-dependent signaling. The present study demonstrated that reduction of cholesterol level decreased and culturing cells in excess cholesterol increased the agonist-induced internalization and desensitization of OPRM1, respectively. Further analyses indicated that modulation of cellular cholesterol level did not affect agonist-induced receptor phosphorylation but did affect membrane translocation of β-arrestins. The translocation of β-arrestins was blocked by cholesterol reduction, and the effect could be reversed by incubating with cholesterol. OptiPrep gradient separation of lipid rafts revealed that excess cholesterol retained more receptors in lipid raft domains and facilitated the recruitment of β-arrestins to these microdomains upon agonist activation. Moreover, excess cholesterol could evoke receptor internalization and protein kinase C-independent extracellular signal-regulated kinases activation upon morphine treatment. Therefore, these results suggest that cholesterol not only can influence OPRM1 localization in lipid rafts but also can effectively enhance the recruitment of β-arrestins and thereby affect the agonist-induced trafficking and agonist-dependent signaling of OPRM1. PMID:21518774

Arabidopsis Chlorophyll Biosynthesis: An Essential Balance between the Methylerythritol Phosphate and Tetrapyrrole Pathways[C][W

PubMed Central

Kim, Se; Schlicke, Hagen; Van Ree, Kalie; Karvonen, Kristine; Subramaniam, Anant; Richter, Andreas; Grimm, Bernhard; Braam, Janet

2013-01-01

Chlorophyll, essential for photosynthesis, is composed of a chlorin ring and a geranylgeranyl diphosphate (GGPP)–derived isoprenoid, which are generated by the tetrapyrrole and methylerythritol phosphate (MEP) biosynthesis pathways, respectively. Although a functional MEP pathway is essential for plant viability, the underlying basis of the requirement has been unclear. We hypothesized that MEP pathway inhibition is lethal because a reduction in GGPP availability results in a stoichiometric imbalance in tetrapyrrolic chlorophyll precursors, which can cause deadly photooxidative stress. Consistent with this hypothesis, lethality of MEP pathway inhibition in Arabidopsis thaliana by fosmidomycin (FSM) is light dependent, and toxicity of MEP pathway inhibition is reduced by genetic and chemical impairment of the tetrapyrrole pathway. In addition, FSM treatment causes a transient accumulation of chlorophyllide and transcripts associated with singlet oxygen-induced stress. Furthermore, exogenous provision of the phytol molecule reduces FSM toxicity when the phytol can be modified for chlorophyll incorporation. These data provide an explanation for FSM toxicity and thereby provide enhanced understanding of the mechanisms of FSM resistance. This insight into MEP pathway inhibition consequences underlines the risk plants undertake to synthesize chlorophyll and suggests the existence of regulation, possibly involving chloroplast-to-nucleus retrograde signaling, that may monitor and maintain balance of chlorophyll precursor synthesis. PMID:24363312

Arabidopsis chlorophyll biosynthesis: an essential balance between the methylerythritol phosphate and tetrapyrrole pathways.

PubMed

Kim, Se; Schlicke, Hagen; Van Ree, Kalie; Karvonen, Kristine; Subramaniam, Anant; Richter, Andreas; Grimm, Bernhard; Braam, Janet

2013-12-01

Chlorophyll, essential for photosynthesis, is composed of a chlorin ring and a geranylgeranyl diphosphate (GGPP)-derived isoprenoid, which are generated by the tetrapyrrole and methylerythritol phosphate (MEP) biosynthesis pathways, respectively. Although a functional MEP pathway is essential for plant viability, the underlying basis of the requirement has been unclear. We hypothesized that MEP pathway inhibition is lethal because a reduction in GGPP availability results in a stoichiometric imbalance in tetrapyrrolic chlorophyll precursors, which can cause deadly photooxidative stress. Consistent with this hypothesis, lethality of MEP pathway inhibition in Arabidopsis thaliana by fosmidomycin (FSM) is light dependent, and toxicity of MEP pathway inhibition is reduced by genetic and chemical impairment of the tetrapyrrole pathway. In addition, FSM treatment causes a transient accumulation of chlorophyllide and transcripts associated with singlet oxygen-induced stress. Furthermore, exogenous provision of the phytol molecule reduces FSM toxicity when the phytol can be modified for chlorophyll incorporation. These data provide an explanation for FSM toxicity and thereby provide enhanced understanding of the mechanisms of FSM resistance. This insight into MEP pathway inhibition consequences underlines the risk plants undertake to synthesize chlorophyll and suggests the existence of regulation, possibly involving chloroplast-to-nucleus retrograde signaling, that may monitor and maintain balance of chlorophyll precursor synthesis.

Epigenetic mediated transcriptional activation of WNT5A participates in arsenical-associated malignant transformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, Taylor J.; Wozniak, Ryan J.; Arizona Cancer Center, University of Arizona, Tucson, AZ 85724

2009-02-15

Arsenic is a human carcinogen with exposure associated with cancer of the lung, skin, and bladder. Many potential mechanisms have been implicated as playing a role in the process of arsenical-induced malignancy including the perturbation of signaling pathways and aberrant epigenetic regulation. We initiated studies to examine the role of a member of the non-canonical WNT signaling pathway, WNT5A, in UROtsa cells and arsenite [URO-ASSC] and monomethylarsonous acid [URO-MSC] malignantly transformed variants. We present data herein that suggest that WNT5A is transcriptionally activated during arsenical-induced malignant transformation. This WNT5A transcriptional activation is correlated with the enrichment of permissive histone modificationsmore » and the reduction of repressive modifications in the WNT5A promoter region. The epigenetic activation of WNT5A expression and acetylation of its promoter remain after the removal of the arsenical, consistent with the maintenance of an anchorage independent growth phenotype in these cells. Additionally, treatment with epigenetic modifying drugs supports a functional role for these epigenetic marks in controlling gene expression. Reduction of WNT5A using lentiviral shRNA greatly attenuated the ability of these cells to grow in an anchorage independent fashion. Extension of our model into human bladder cancer cell lines indicates that each of the cell lines examined also express WNT5A. Taken together, these data suggest that the epigenetic remodeling of the WNT5A promoter is correlated with its transcriptional activation and this upregulation likely participates in arsenical-induced malignant transformation.« less

Labrador tea (Rhododendron groenlandicum) attenuates insulin resistance in a diet-induced obesity mouse model.

PubMed

Ouchfoun, Meriem; Eid, Hoda M; Musallam, Lina; Brault, Antoine; Li, Shilin; Vallerand, Diane; Arnason, John T; Haddad, Pierre S

2016-04-01

Using a diet-induced obesity (DIO) mouse model, we investigated the antidiabetic effect of Labrador tea [Rhododendron groenlandicum (Oeder) Kron and Judd], a beverage and medicinal tea used by the Cree Nations of northern Quebec. C57BL6 mice were divided into five groups and given standard chow (~4 % of lipids) or high-fat diet (~35 % of lipids) for 8 weeks until they became obese and insulin resistant. Treatment began by adding the plant extract at three doses (125, 250 and 500 mg/kg) to the high-fat diet for another 8 weeks. At the end of the study, insulin-sensitive tissues (liver, skeletal muscle, adipose tissue) were collected to investigate the plant's molecular mechanisms. Labrador tea significantly reduced blood glucose (13 %), the response to an oral glucose tolerance test (18.2 %) and plasma insulin (65 %) while preventing hepatic steatosis (42 % reduction in hepatic triglyceride levels) in DIO mice. It stimulated insulin-dependent Akt pathway (55 %) and increased the expression of GLUT4 (53 %) in skeletal muscle. In the liver, Labrador tea stimulated the insulin-dependent Akt and the insulin-independent AMP-activated protein kinase pathways. The improvement in hepatic steatosis observed in DIO-treated mice was associated with a reduction in inflammation (through the IKK α/β) and a decrease in the hepatic content of SREBP-1 (39 %). Labrador tea exerts potential antidiabetic action by improving insulin sensitivity and mitigating high-fat diet-induced obesity and hyperglycemia. They validate the safety and efficacy of this plant, a promising candidate for culturally relevant complementary treatment in Cree diabetics.

Neuroprotective effects of seaweeds against 6-hydroxidopamine-induced cell death on an in vitro human neuroblastoma model.

PubMed

Silva, Joana; Alves, Celso; Pinteus, Susete; Mendes, Susana; Pedrosa, Rui

2018-02-14

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the central nervous system. Although the causes of PD pathogenesis remain incomplete, some evidences has suggested that oxidative stress is an important mediator in its pathogenesis. The aim of this study was to evaluate the protective effects of seaweeds with high antioxidant activity on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in the human neuroblastoma cell line SH-SY5Y, as well as the associated intracellular signaling pathways. Cell viability studies were assessed by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium (MTT) bromide assay and the intracellular signaling pathways analyzed were: hydrogen peroxide (H 2 O 2 ) production, changes in the mitochondrial membrane potential and Caspase-3 activity. Exposure of SH-SY5Y cells to 6-OHDA (10-1000 μM) reduced cell's viability in a concentration and time-dependent manner. The data suggest that the cell death induced by 6-OHDA was mediated by an increase of H 2 O 2 production, the depolarization of mitochondrial membrane potential and the increase of Caspase-3 activity. Extracts from S. polyshides, P. pavonica, S. muticum, C. tomentosum and U. compressa revealed to efficiently protect cell's viability in the presence of 6-OHDA (100 μM; 24 h). These effects appear to be associated with the reduction of H 2 O 2 cell's production, the protection of mitochondrial membrane's potential and the reduction of Caspase-3 activity. These results suggest that seaweeds can be a promising source of new compounds with neuroprotective potential.

Autophagy contributes to 4-Amino-2-Trifluoromethyl-Phenyl Retinate-induced differentiation in human acute promyelocytic leukemia NB4 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yue; Li, Ge; Wang, Ke

As a classic differentiation agent, all-trans retinoic acid (ATRA) has been widely used in treatment of acute promyelocytic leukemia (APL). However, clinical application of ATRA has limitations. Our previous studies suggested that 4-Amino-2-Trifluoromethyl-Phenyl Retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative designed and synthesized by our team, could induce differentiation of APL cells in vivo and in vitro. To explore the underlying mechanism of ATPR, the effect of ATPR on autophagy of APL cells was observed in the present study. The results showed that the differentiation effect of ATPR on APL cells was accompanied with autophagy induction and PML-RARαmore » degradation via activating Notch1 signaling pathway. Moreover, inhibition of autophagy using 3-methyladenine (3-MA) or small interfering RNA (siRNA) that targets essential autophagy gene ATG5 abrogated the ATPR-induced cell differentiation. Furthermore, when pretreated with DAPT, a γ-secretase inhibitor, the Notch1 signaling pathway was blocked in APL cells, followed by the reduction of ATPR-induced autophagy and differentiation. Taken together, these results suggested that autophagy play an important role in ATPR-induced cell differentiation, which may provide a novel approach to cure APL patients. - Highlights: • ATPR induces autophagy in APL cell line NB4 cells. • Autophagy induction is essential for cell differentiation in NB4 cells. • Notch1 signaling is involved in ATPR-induced autophagy and differentiation in NB4 cells.« less

Association of Wnt1-inducible signaling pathway protein-1 with the proliferation, migration and invasion in gastric cancer cells.

PubMed

Jia, Shuqin; Qu, Tingting; Feng, Mengmeng; Ji, Ke; Li, Ziyu; Jiang, Wenguo; Ji, Jiafu

2017-06-01

Wnt1-inducible signaling pathway protein-1 is a cysteine-rich protein that belongs to the CCN family, which has been implicated in mediating the occurrence and progression through distinct molecular mechanisms in several tumor types. However, the association of Wnt1-inducible signaling pathway protein-1 with gastric cancer and the related molecular mechanisms remain to be elucidated. Therefore, this study aimed to clarify the biological role of Wnt1-inducible signaling pathway protein-1 in the proliferation, migration, and invasion in gastric cancer cells and further investigated the associated molecular mechanism on these biological functions. We first detected the expression level of Wnt1-inducible signaling pathway protein-1 in gastric cancer, and the reverse transcription polymerase chain reaction have shown that Wnt1-inducible signaling pathway protein-1 expression levels were upregulated in gastric cancer tissues. The expression of Wnt1-inducible signaling pathway protein-1 in gastric cancer cell lines was also detected by quantitative real-time polymerase chain reaction and Western blotting. Furthermore, two gastric cancer cell lines with high expression of Wnt1-inducible signaling pathway protein-1 were selected to explore the biological function of Wnt1-inducible signaling pathway protein-1 in gastric cancer. Function assays indicated that knockdown of Wnt1-inducible signaling pathway protein-1 suppressed cell proliferation, migration, and invasion in BGC-823 and AGS gastric cancer cells. Further investigation of mechanisms suggested that cyclinD1 was identified as one of Wnt1-inducible signaling pathway protein-1 related genes to accelerate proliferation in gastric cancer cells. In addition, one pathway of Wnt1-inducible signaling pathway protein-1 induced migration and invasion was mainly through the enhancement of epithelial-to-mesenchymal transition progression. Taken together, our findings presented the first evidence that Wnt1-inducible signaling pathway protein-1 was upregulated in gastric cancer and acted as an oncogene by promoting proliferation, migration, and invasion in gastric cancer cells.

Dual PI3K/mTOR Inhibition in Colorectal Cancers with APC and PIK3CA Mutations.

PubMed

Foley, Tyler M; Payne, Susan N; Pasch, Cheri A; Yueh, Alex E; Van De Hey, Dana R; Korkos, Demetra P; Clipson, Linda; Maher, Molly E; Matkowskyj, Kristina A; Newton, Michael A; Deming, Dustin A

2017-02-09

Therapeutic targeting of the PI3K pathway is an active area of research in multiple cancer types, including breast and endometrial cancers. This pathway is commonly altered in cancer and plays an integral role in numerous vital cellular functions. Mutations in the PIK3CA gene, resulting in a constitutively active form of PI3K, often occur in colorectal cancer, though the population of patients who would benefit from targeting this pathway has yet to be identified. In human colorectal cancers, PIK3CA mutations most commonly occur concomitantly with loss of adenomatous polyposis coli (APC). Here, treatment strategies are investigated that target the PI3K pathway in colon cancers with mutations in APC and PIK3CA Colorectal cancer spheroids with Apc and Pik3ca mutations were generated and characterized confirming that these cultures represent the tumors from which they were derived. Pan and alpha isomer-specific PI3K inhibitors did not induce a significant treatment response, whereas the dual PI3K/mTOR inhibitors BEZ235 and LY3023414 induced a dramatic treatment response through decreased cellular proliferation and increased differentiation. The significant treatment responses were confirmed in mice with Apc and Pik3ca -mutant colon cancers as measured using endoscopy with a reduction in median lumen occlusion of 53% with BEZ235 and a 24% reduction with LY3023414 compared with an increase of 53% in controls ( P < 0.001 and P = 0.03, respectively). This response was also confirmed with 18 F-FDG microPET/CT imaging. Implications: Spheroid models and transgenic mice suggest that dual PI3K/mTOR inhibition is a potential treatment strategy for APC and PIK3CA -mutant colorectal cancers. Thus, further clinical studies of dual PI3K/mTOR inhibitors are warranted in colorectal cancers with these mutations. Mol Cancer Res; 15(3); 1-11. ©2016 AACR. ©2016 American Association for Cancer Research.

Notch1 Mediates Preconditioning Protection Induced by GPER in Normotensive and Hypertensive Female Rat Hearts.

PubMed

Rocca, Carmine; Femminò, Saveria; Aquila, Giorgio; Granieri, Maria C; De Francesco, Ernestina M; Pasqua, Teresa; Rigiracciolo, Damiano C; Fortini, Francesca; Cerra, Maria C; Maggiolini, Marcello; Pagliaro, Pasquale; Rizzo, Paola; Angelone, Tommaso; Penna, Claudia

2018-01-01

G protein-coupled estrogen receptor (GPER) is an estrogen receptor expressed in the cardiovascular system. G1, a selective GPER ligand, exerts cardiovascular effects through activation of the PI3K-Akt pathway and Notch signaling in normotensive animals. Here, we investigated whether the G1/GPER interaction is involved in the limitation of infarct size, and improvement of post-ischemic contractile function in female spontaneous hypertensive rat (SHR) hearts. In this model, we also studied Notch signaling and key components of survival pathway, namely PI3K-Akt, nitric oxide synthase (NOS) and mitochondrial K + -ATP (MitoKATP) channels. Rat hearts isolated from female SHR underwent 30 min of global, normothermic ischemia and 120 min of reperfusion. G1 (10 nM) alone or specific inhibitors of GPER, PI3K/NOS and MitoKATP channels co-infused with G1, just before I/R, were studied. The involvement of Notch1 was studied by Western blotting. Infarct size and left ventricular pressure were measured. To confirm endothelial-independent G1-induced protection by Notch signaling, H9c2 cells were studied with specific inhibitor, N -[ N -(3,5 difluorophenacetyl)-L-alanyl]- S -phenylglycine t -butyl ester (DAPT, 5 μM), of this signaling. Using DAPT, we confirmed the involvement of G1/Notch signaling in limiting infarct size in heart of normotensive animals. In the hypertensive model, G1-induced reduction in infarct size and improvement of cardiac function were prevented by the inhibition of GPER, PI3K/NOS, and MitoKATP channels. The involvement of Notch was confirmed by western blot in the hypertensive model and by the specific inhibitor in the normotensive model and cardiac cell line. Our results suggest that GPERs play a pivotal role in mediating preconditioning cardioprotection in normotensive and hypertensive conditions. The G1-induced protection involves Notch1 and is able to activate the survival pathway in the presence of comorbidity. Several pathological conditions, including hypertension, reduce the efficacy of ischemic conditioning strategies. However, G1-induced protection can result in significant reduction of I/R injury also female in hypertensive animals. Further studies may ascertain the clinical translation of the present results.

Polychlorinated biphenyls (PCB 101, PCB 153 and PCB 180) alter leptin signaling and lipid metabolism in differentiated 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrante, Maria C.; Amero, Paola; Santoro, Anna

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) are highly lipophilic environmental contaminants that accumulate in lipid-rich tissues, such as adipose tissue. Here, we reported the effects induced by PCBs 101, 153 and 180, three of the six NDL-PCBs defined as indicators, on mature 3T3-L1 adipocytes. We observed an increase in lipid content, in leptin gene expression and a reduction of leptin receptor expression and signaling, when cells were exposed to PCBs, alone or in combination. These modifications were consistent with the occurrence of “leptin-resistance” in adipose tissue, a typical metabolic alteration related to obesity. Therefore, we investigated how PCBs affect the expression ofmore » pivotal proteins involved in the signaling of leptin receptor. We evaluated the PCB effect on the intracellular pathway JAK/STAT, determining the phosphorylation of STAT3, a downstream activator of the transcription of leptin gene targets, and the expression of SOCS3 and PTP1B, two important regulators of leptin resistance. In particular, PCBs 153 and 180 or all PCB combinations induced a significant reduction in pSTAT3/STAT3 ratio and an increase in PTP1B and SOCS3, evidencing an additive effect. The impairment of leptin signaling was associated with the reduction of AMPK/ACC pathway activation, leading to the increase in lipid content. These pollutants were also able to increase the transcription of inflammatory cytokines (IL-6 and TNFα). It is worthy to note that the PCB concentrations used are comparable to levels detectable in human adipose tissue. Our data strongly support the hypothesis that NDL-PCBs may interfere with the lipid metabolism contributing to the development of obesity and related diseases. - Highlights: • NDL-PCBs alter lipid content and metabolism in 3T3-L1 adipocytes. • Impairment of leptin signaling was induced by NDL-PCBs. • NDL-PCBs reduce AMPK and ACC activation. • NDL-PCBs induce the synthesis of pro-inflammatory cytokine by adipocytes.« less

Endoplasmic reticulum stress (ER-stress) by 2-deoxy-D-glucose (2DG) reduces cyclooxygenase-2 (COX-2) expression and N-glycosylation and induces a loss of COX-2 activity via a Src kinase-dependent pathway in rabbit articular chondrocytes.

PubMed

Yu, Seon-Mi; Kim, Song-Ja

2010-11-30

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG- modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.

Silibinin enhances the repair of ultraviolet B-induced DNA damage by activating p53-dependent nucleotide excision repair mechanism in human dermal fibroblasts

PubMed Central

Guillermo-Lagae, Ruth; Deep, Gagan; Ting, Harold; Agarwal, Chapla; Agarwal, Rajesh

2015-01-01

Ultraviolet radiation B (UVB) is the main cause of DNA damage in epidermal cells; and if not repaired, this DNA damage leads to skin cancer. In earlier studies, we have reported that natural flavonolignan silibinin exerts strong chemopreventive efficacy against UVB-induced skin damage and carcinogenesis; however mechanistic studies are still being actively pursued. Here, we investigated the role of nucleotide excision repair (NER) pathway in silibinin's efficacy to repair UVB-induced DNA damage. Normal human dermal fibroblasts (NHDFs) were exposed to UVB (1 mJ/cm2) with pre- or post- silibinin (100 μM) treatment, and cyclobutane pyrimidine dimers (CPDs) formation/repair was measured. Results showed that post-UVB silibinin treatment accelerates DNA repair via activating the NER pathway including the expression of XPA (xeroderma pigmentosum complementation group A), XPB, XPC, and XPG. In UVB exposed fibroblasts, silibinin treatment also increased p53 and GADD45α expression; the key regulators of the NER pathway and DNA repair. Consistently, post-UVB silibinin treatment increased the mRNA transcripts of XPA and GADD45α. Importantly, silibinin showed no effect on UVB-induced DNA damage repair in XPA- and XPB-deficient human dermal fibroblasts suggesting their key role in silibinin-mediated DNA damage repair. Moreover, in the presence of pifithrin-α, an inhibitor of p53, the DNA repair efficacy of silibinin was compromised associated with a reduction in XPA and GADD45α transcripts. Together, these findings suggest that silibinin's efficacy against UVB-induced photodamage is primarily by inhibiting NER and p53; and these findings further support silibinin's usage as a potential inexpensive, effective, and non-toxic agent for skin cancer chemoprevention. PMID:26447614

Silibinin enhances the repair of ultraviolet B-induced DNA damage by activating p53-dependent nucleotide excision repair mechanism in human dermal fibroblasts.

PubMed

Guillermo-Lagae, Ruth; Deep, Gagan; Ting, Harold; Agarwal, Chapla; Agarwal, Rajesh

2015-11-24

Ultraviolet radiation B (UVB) is the main cause of DNA damage in epidermal cells; and if not repaired, this DNA damage leads to skin cancer. In earlier studies, we have reported that natural flavonolignan silibinin exerts strong chemopreventive efficacy against UVB-induced skin damage and carcinogenesis; however mechanistic studies are still being actively pursued. Here, we investigated the role of nucleotide excision repair (NER) pathway in silibinin's efficacy to repair UVB-induced DNA damage. Normal human dermal fibroblasts (NHDFs) were exposed to UVB (1 mJ/cm2) with pre- or post- silibinin (100 μM) treatment, and cyclobutane pyrimidine dimers (CPDs) formation/repair was measured. Results showed that post-UVB silibinin treatment accelerates DNA repair via activating the NER pathway including the expression of XPA (xeroderma pigmentosum complementation group A), XPB, XPC, and XPG. In UVB exposed fibroblasts, silibinin treatment also increased p53 and GADD45α expression; the key regulators of the NER pathway and DNA repair. Consistently, post-UVB silibinin treatment increased the mRNA transcripts of XPA and GADD45α. Importantly, silibinin showed no effect on UVB-induced DNA damage repair in XPA- and XPB-deficient human dermal fibroblasts suggesting their key role in silibinin-mediated DNA damage repair. Moreover, in the presence of pifithrin-α, an inhibitor of p53, the DNA repair efficacy of silibinin was compromised associated with a reduction in XPA and GADD45α transcripts. Together, these findings suggest that silibinin's efficacy against UVB-induced photodamage is primarily by inhibiting NER and p53; and these findings further support silibinin's usage as a potential inexpensive, effective, and non-toxic agent for skin cancer chemoprevention.

Rapamycin prevents N-methyl-D-aspartate-induced retinal damage through an ERK-dependent mechanism in rats.

PubMed

Ichikawa, Atsuko; Nakahara, Tsutomu; Kurauchi, Yuki; Mori, Asami; Sakamoto, Kenji; Ishii, Kunio

2014-06-01

Recent studies have demonstrated that inhibition of the mammalian target of rapamycin (mTOR) protects against neuronal injury, but the mechanisms underlying this protection are not fully understood. The present study investigates whether rapamycin, an inhibitor of the mTOR pathway, protects against N-methyl-D-aspartate (NMDA)-induced retinal neurotoxicity and whether the extracellular signal-regulated kinase (ERK) pathway contributes to this protective effect in rats. Significant cell loss in the ganglion cell layer and a reduction in thickness of the inner plexiform layer were observed 7 days after a single intravitreal injection of NMDA (200 nmol/eye). These NMDA-induced morphological changes were significantly reduced by rapamycin (20 nmol/eye). The number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells had increased 6 hr after NMDA injection, an effect that was significantly attenuated by rapamycin. The ERK inhibitor U0126 (1 nmol/eye) almost completely abolished rapamycin's inhibition of NMDA-induced apoptosis. Immunohistochemical studies showed that NMDA caused a time-dependent increase in levels of the phosphorylated form of the ribosomal protein S6 (pS6), a downstream indicator of mTOR activity. The increased pS6 levels were markedly decreased by rapamycin. Both NMDA and rapamycin increased the level of phosphorylated ERK (pERK) in Müller cells, and coinjection of both agents further increased pERK levels. These results suggest that rapamycin has a neuroprotective effect against NMDA-induced retinal neurotoxicity and that this effect could be patially mediated by activation of the ERK pathway in retinal Müller cells. Copyright © 2014 Wiley Periodicals, Inc.

The chalcone flavokawain B induces G2/M cell-cycle arrest and apoptosis in human oral carcinoma HSC-3 cells through the intracellular ROS generation and downregulation of the Akt/p38 MAPK signaling pathway.

PubMed

Hseu, You-Cheng; Lee, Meng-Shiou; Wu, Chi-Rei; Cho, Hsin-Ju; Lin, Kai-Yuan; Lai, Guan-Hua; Wang, Sheng-Yang; Kuo, Yueh-Hsiung; Kumar, K J Senthil; Yang, Hsin-Ling

2012-03-07

Chalcones have been described to represent cancer chemopreventive food components that are rich in fruits and vegetables. In this study, we examined the anti-oral cancer effect of flavokawain B (FKB), a naturally occurring chalcone isolated from Alpinia pricei (shell gingers), and revealed its molecular mechanism of action. Treatment of human oral carcinoma (HSC-3) cells with FKB (1.25-10 μg/mL; 4.4-35.2 μM) inhibited cell viability and caused G(2)/M arrest through reductions in cyclin A/B1, Cdc2, and Cdc25C levels. Moreover, FKB treatment resulted in the induction of apoptosis, which was associated with DNA fragmentation, mitochondria dysfunction, cytochrome c and AIF release, caspase-3 and caspase-9 activation, and Bcl-2/Bax dysregulation. Furthermore, increased Fas activity and procaspase-8, procaspase-4, and procaspase-12 cleavages were accompanied by death receptor and ER-stress, indicating the involvement of mitochondria, death-receptor, and ER-stress signaling pathways. FKB induces apoptosis through ROS generation as evidenced by the upregulation of oxidative-stress markers HO-1/Nrf2. This mechanism was further confirmed by the finding that the antioxidant N-acetylcysteine (NAC) significantly blocked ROS generation and consequently inhibited FKB-induced apoptosis. Moreover, FKB downregulated the phosphorylation of Akt and p38 MAPK, while their inhibitors LY294002 and SB203580, respectively, induced G(2)/M arrest and apoptosis. The profound reduction in cell number was observed in combination treatment with FKB and Akt/p38 MAPK inhibitors, indicating that the disruption of Akt and p38 MAPK cascades plays a functional role in FKB-induced G(2)/M arrest and apoptosis in HSC-3 cells.

Immunomodulatory Effect of Flavonoids of Blueberry (Vaccinium corymbosum L.) Leaves via the NF-κB Signal Pathway in LPS-Stimulated RAW 264.7 Cells.

PubMed

Shi, Dazhi; Xu, Mengyi; Ren, Mengyue; Pan, Enshan; Luo, Chaohua; Zhang, Wei; Tang, Qingfa

2017-01-01

This study aimed to explore the immunoregulatory effect of flavonoids of blueberry ( Vaccinium corymbosum L.) leaves (FBL). The flavonoids of blueberry leaves were prepared with 70% ethanol and were identified by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-Tof-MS). The immunoregulatory effect and possible regulatory mechanisms of FBL were investigated in lipopolysaccharide- (LPS-) induced RAW 264.7 cells. According to the results of UPLC/Q-Tof-MS, nine flavonoids of blueberry leaves were identified. FBL showed a significant reduction in the production of TNF- α in LPS-stimulated RAW 264.7 cells. FBL significantly decreased the expression of NF- κ B p65 and P-NF- κ B p65 in LPS-induced RAW 264.7 cells in a dose-dependent manner. Our study showed the immunoregulatory effect of FBL through the suppression of TNF- α via the NF- κ B signal pathway.

Immunomodulatory Effect of Flavonoids of Blueberry (Vaccinium corymbosum L.) Leaves via the NF-κB Signal Pathway in LPS-Stimulated RAW 264.7 Cells

PubMed Central

Shi, Dazhi; Xu, Mengyi; Pan, Enshan; Luo, Chaohua

2017-01-01

Objective This study aimed to explore the immunoregulatory effect of flavonoids of blueberry (Vaccinium corymbosum L.) leaves (FBL). Methods The flavonoids of blueberry leaves were prepared with 70% ethanol and were identified by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-Tof-MS). The immunoregulatory effect and possible regulatory mechanisms of FBL were investigated in lipopolysaccharide- (LPS-) induced RAW 264.7 cells. Results According to the results of UPLC/Q-Tof-MS, nine flavonoids of blueberry leaves were identified. FBL showed a significant reduction in the production of TNF-α in LPS-stimulated RAW 264.7 cells. FBL significantly decreased the expression of NF-κB p65 and P-NF-κB p65 in LPS-induced RAW 264.7 cells in a dose-dependent manner. Conclusion Our study showed the immunoregulatory effect of FBL through the suppression of TNF-α via the NF-κB signal pathway. PMID:29445755

Withaferin A inhibits JAK/STAT3 signaling and induces apoptosis of human renal carcinoma Caki cells.

PubMed

Um, Hee Jung; Min, Kyoung-Jin; Kim, Dong Eun; Kwon, Taeg Kyu

2012-10-12

Withaferin A, the active component of Withania somnifera, causes cytotoxicity in a variety of tumor cell lines. In this study, we show that withaferin A inhibits constitutive and IL-6-induced phosphorylation of STAT3 (on Tyr705), but not IFN-γ-induced STAT1 phosphorylation. Withaferin A-induced down-regulation of STAT3 activation is associated with a reduction in Janus-activated kinase 2 (JAK2) activity. Withaferin A also down-regulates the expression of STAT3 regulated genes such as Bcl-xL, Bcl-2, cyclin D1 and survivin. The apoptotic effect of withaferin A in Caki human renal cancer cells was investigated. Withaferin A induced dose-dependent apoptotic cell death in Caki cells, as measured by FACS analysis and PARP cleavage. Furthermore, overexpression of STAT3 attenuated withaferin A-induced apoptosis. Taken together, the present study provides strong evidence that down-regulation of the STAT3 signaling pathway mediates withaferin A-induced apoptosis. Copyright © 2012 Elsevier Inc. All rights reserved.

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide.

PubMed

Bonaventura, C; Godette, G; Tesh, S; Holm, D E; Bonaventura, J; Crumbliss, A L; Pearce, L L; Peterson, J

1999-02-26

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide. Furthermore, this internal electron-transfer pathway is more readily established at low Cu(II) concentrations in Hb Deer Lodge (beta2His --> Arg) and other species lacking His-beta2 than in Hb A0. This difference is consistent with preferential binding of Cu(II) in Hb A0 to a high affinity site involving His-beta2, which is ineffective in promoting electron exchange between Cu(II) and the beta heme iron. Effective electron transfer is thus affected by Hb type but is not governed by the R left arrow over right arrow T conformational equilibrium. The beta hemes in Cu(II)-metHb are reduced under CO at rates close to those observed for cytochrome c oxidase, where heme and copper are present together in the oxygen-binding site and where internal electron transfer also occurs.

Reactive oxygen species-mediated synergistic and preferential induction of cell death and reduction of clonogenic resistance in breast cancer cells by combined cisplatin and FK228.

PubMed

Pluchino, Lenora Ann; Choudhary, Shambhunath; Wang, Hwa-Chain Robert

2016-10-10

Safe and effective combination chemotherapy regimens against breast cancer are lacking. We used our cellular system, consisting of the non-cancerous human breast epithelial MCF10A cell line and its derived tumorigenic, oncogenic H-Ras-expressing, MCF10A-Ras cell line, to investigate the effectiveness of a combination chemotherapy regimen in treating breast cancer cells using two FDA-approved agents, cisplatin and FK228. Cisplatin and FK228 significantly, synergistically, and preferentially induced death and reduced drug resistance of MCF10A-Ras versus MCF10A cells. The ERK-Nox-ROS pathway played a major role in both synergistic cell death induction and GSH-level reduction, which contributed to the synergistic suppression of drug resistance in cells. Enhancement of the Ras-ERK-Nox pathway by combined cisplatin and FK228 significantly increased ROS levels, leading to induction of death, reduction of drug resistance, and induction of DNA damage and oxidation in cancerous MCF10A-Ras cells. Furthermore, synergistic induction of cell death and reduction of drug resistance by combined cisplatin and FK228 in breast cells is independent of their estrogen receptor status. Our study suggests that combined cisplatin and FK228 should be considered in clinical trials as a new regimen for therapeutic control of breast cancers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Levodopa/Benserazide Loaded Microspheres Alleviate L-dopa Induced Dyskinesia through Preventing the Over-Expression of D1R/Shp-2/ERK1/2 Signaling Pathway in a Rat Model of Parkinson's Disease

PubMed Central

Wan, Ying; Wu, Na; Song, Lu; Wang, Xijin; Liu, Zhenguo; Yuan, Weien; Gan, Jing

2017-01-01

Background: The long-term intermittent Levodopa (L-dopa) stimulation contributes to an aberrant activation of D1 receptor (D1R) mediated extracellular signal-regulated kinases1/2 (ERK1/2) in the striatal medium spiny neurons, resulting in the occurrence of L-dopa induced dyskinesia (LID). Recently, a novel signaling pathway, D1R/Shp-2/ERK1/2, was proposed to be required for the occurrence of LID. Here we designed the study in which two different methods of L-dopa delivery [continuous dopamine stimulation (CDS) vs. intermittent dopamine stimulation] were used to further identify: (1) the role of D1R/Shp-2/ERK1/2 signaling pathway in the occurrence of LID; (2) whether CDS alleviated LID though preventing the over-expression of the D1R/Shp-2/ERK1/2 signaling pathway. Methods: 6-OHDA-lesioned rat models of Parkinson's disease (PD) were randomly divided into two groups to receive intermittent L-dopa stimulation (L-dopa/benserazide standard group, LS group) or CDS (L-dopa/benserazide loaded microspheres, LBM group) for 21 days. Dyskinesia and anti-parkinsonian effect were compared between the two groups through the AIMs assessment and cylinder test. The critical protein changes in the D1R/Shp-2/ERK1/2 signaling pathway were compared between the two groups through Western blotting. Results: Intermittent L-dopa administration induced serious dyskinetic movements in the 6-OHDA-lesioned rats, and the anti-parkinsonian effect of L-dopa was gradually counteracted by the occurrence of dyskinesia. Intermittent L-dopa administration enhanced the expression of membrane D1R, and induced a robust increase of phosphorylation of Shp-2, Src, DARPP-32, and ERK1/2 in the 6-OHDA-lesioned striatum. In contrast, CDS played a dose-dependent anti-parkinsonian role, without inducing such apparent dyskinetic movements. Moreover, CDS induced no change of membrane D1R expression or phosphorylation of Shp-2, Src, DARPP-32, and ERK1/2 in the 6-OHDA-lesioned striatum. Conclusion: The aberrant activation of D1R/Shp-2 complex was evidenced to be required for the D1R mediating ERK1/2 phosphorylation and the occurrence of LID. CDS effectively prevented the overexpression of D1R/Shp-2/ERK1/2 signaling pathway, resulting in the reduction of LID in 6-OHDA-lesioned rats model of PD. PMID:29093677

Quercetin inhibits prostate cancer by attenuating cell survival and inhibiting anti-apoptotic pathways.

PubMed

Ward, Ashley B; Mir, Hina; Kapur, Neeraj; Gales, Dominique N; Carriere, Patrick P; Singh, Shailesh

2018-06-14

Despite recent advances in diagnosis and treatment, prostate cancer (PCa) remains the leading cause of cancer-related deaths in men. Current treatments offered in the clinics are often toxic and have severe side effects. Hence, to treat and manage PCa, new agents with fewer side effects or having potential to reduce side effects of conventional therapy are needed. In this study, we show anti-cancer effects of quercetin, an abundant bioflavonoid commonly used to treat prostatitis, and defined quercetin-induced cellular and molecular changes leading to PCa cell death. Cell viability was assessed using MTT. Cell death mode, mitochondrial outer membrane potential, and oxidative stress levels were determined by flow cytometry using Annexin V-7 AAD dual staining kit, JC-1 dye, and ROS detection kit, respectively. Antibody microarray and western blot were used to delineate the molecular changes induced by quercetin. PCa cells treated with various concentrations of quercetin showed time- and dose-dependent decrease in cell viability compared to controls, without affecting normal prostate epithelial cells. Quercetin led to apoptotic and necrotic cell death in PCa cells by affecting the mitochondrial integrity and disturbing the ROS homeostasis depending upon the genetic makeup and oxidative status of the cells. LNCaP and PC-3 cells that have an oxidative cellular environment showed ROS quenching after quercetin treatment while DU-145 showed rise in ROS levels despite having a highly reductive environment. Opposing effects of quercetin were also observed on the pro-survival pathways of PCa cells. PCa cells with mutated p53 (DU-145) and increased ROS showed significant reduction in the activation of pro-survival Akt pathway while Raf/MEK were activated in response to quercetin. PC-3 cells lacking p53 and PTEN with reduced ROS levels showed significant activation of Akt and NF-κB pathway. Although some of these changes are commonly associated with oncogenic response, the cumulative effect of these alterations is PCa cell death. Our results demonstrated quercetin exerts its anti-cancer effects by modulating ROS, Akt, and NF-κB pathways. Quercetin could be used as a chemopreventive option as well as in combination with chemotherapeutic drugs to improve clinical outcomes of PCa patients.

A WRKY transcription factor from Withania somnifera regulates triterpenoid withanolide accumulation and biotic stress tolerance through modulation of phytosterol and defense pathways.

PubMed

Singh, Anup Kumar; Kumar, Sarma Rajeev; Dwivedi, Varun; Rai, Avanish; Pal, Shaifali; Shasany, Ajit K; Nagegowda, Dinesh A

2017-08-01

Withania somnifera produces pharmacologically important triterpenoid withanolides that are derived via phytosterol pathway; however, their biosynthesis and regulation remain to be elucidated. A jasmonate- and salicin-inducible WRKY transcription factor from W. somnifera (WsWRKY1) exhibiting correlation with withaferin A accumulation was functionally characterized employing virus-induced gene silencing and overexpression studies combined with transcript and metabolite analyses, and chromatin immunoprecipitation assay. WsWRKY1 silencing resulted in stunted plant growth, reduced transcripts of phytosterol pathway genes with corresponding reduction in phytosterols and withanolides in W. somnifera. Its overexpression elevated the biosynthesis of triterpenoids in W. somnifera (phytosterols and withanolides), as well as tobacco and tomato (phytosterols). Moreover, WsWRKY1 binds to W-box sequences in promoters of W. somnifera genes encoding squalene synthase and squalene epoxidase, indicating its direct regulation of triterpenoid pathway. Furthermore, while WsWRKY1 silencing in W. somnifera compromised the tolerance to bacterial growth, fungal infection, and insect feeding, its overexpression in tobacco led to improved biotic stress tolerance. Together these findings demonstrate that WsWRKY1 has a positive regulatory role on phytosterol and withanolides biosynthesis, and defense against biotic stress, highlighting its importance as a metabolic engineering tool for simultaneous improvement of triterpenoid biosynthesis and plant defense. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Sulforaphane protects against cytokine- and streptozotocin-induced {beta}-cell damage by suppressing the NF-{kappa}B pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Mi-Young; Kim, Eun-Kyung; Moon, Woo-Sung

2009-02-15

Sulforaphane (SFN) is an indirect antioxidant that protects animal tissues from chemical or biological insults by stimulating the expression of several NF-E2-related factor-2 (Nrf2)-regulated phase 2 enzymes. Treatment of RINm5F insulinoma cells with SFN increases Nrf2 nuclear translocation and expression of phase 2 enzymes. In this study, we investigated whether the activation of Nrf2 by SFN treatment or ectopic overexpression of Nrf2 inhibited cytokine-induced {beta}-cell damage. Treatment of RIN cells with IL-1{beta} and IFN-{gamma} induced {beta}-cell damage through a NF-{kappa}B-dependent signaling pathway. Activation of Nrf2 by treatment with SFN and induction of Nrf2 overexpression by transfection with Nrf2 prevented cytokinemore » toxicity. The mechanism by which Nrf2 activation inhibited NF-{kappa}B-dependent cell death signals appeared to involve the reduction of oxidative stress, as demonstrated by the inhibition of cytokine-induced H{sub 2}O{sub 2} production. The protective effect of SFN was further demonstrated by the restoration of normal insulin secreting responses to glucose in cytokine-treated rat pancreatic islets. Furthermore, pretreatment with SFN blocked the development of type 1 diabetes in streptozotocin-treated mice.« less

Exposure to Endocrine Disruptor Induces Transgenerational Epigenetic Deregulation of MicroRNAs in Primordial Germ Cells

PubMed Central

Brieño-Enríquez, Miguel A.; García-López, Jesús; Cárdenas, David B.; Guibert, Sylvain; Cleroux, Elouan; Děd, Lukas; Hourcade, Juan de Dios; Pěknicová, Jana; Weber, Michael; del Mazo, Jesús

2015-01-01

In mammals, germ cell differentiation is initiated in the Primordial Germ Cells (PGCs) during fetal development. Prenatal exposure to environmental toxicants such as endocrine disruptors may alter PGC differentiation, development of the male germline and induce transgenerational epigenetic disorders. The anti-androgenic compound vinclozolin represents a paradigmatic example of molecule causing transgenerational effects on germ cells. We performed prenatal exposure to vinclozolin in mice and analyzed the phenotypic and molecular changes in three successive generations. A reduction in the number of embryonic PGCs and increased rate of apoptotic cells along with decrease of fertility rate in adult males were observed in F1 to F3 generations. Blimp1 is a crucial regulator of PGC differentiation. We show that prenatal exposure to vinclozolin deregulates specific microRNAs in PGCs, such as miR-23b and miR-21, inducing disequilibrium in the Lin28/let-7/Blimp1 pathway in three successive generations of males. As determined by global maps of cytosine methylation, we found no evidence for prominent changes in DNA methylation in PGCs or mature sperm. Our data suggest that embryonic exposure to environmental endocrine disruptors induces transgenerational epigenetic deregulation of expression of microRNAs affecting key regulatory pathways of germ cells differentiation. PMID:25897752

JNK and NADPH Oxidase Involved in Fluoride-Induced Oxidative Stress in BV-2 Microglia Cells

PubMed Central

Yan, Ling; Liu, Shengnan; Wang, Chen; Wang, Fei; Song, Yingli; Yan, Nan; Xi, Shuhua; Liu, Ziyou; Sun, Guifan

2013-01-01

Excessive fluoride may cause central nervous system (CNS) dysfunction, and oxidative stress is a recognized mode of action of fluoride toxicity. In CNS, activated microglial cells can release more reactive oxygen species (ROS), and NADPH oxidase (NOX) is the major enzyme for the production of extracellular superoxide in microglia. ROS have been characterized as an important secondary messenger and modulator for various mammalian intracellular signaling pathways, including the MAPK pathways. In this study we examined ROS production and TNF-α, IL-1β inflammatory cytokines releasing, and the expression of MAPKs in BV-2 microglia cells treated with fluoride. We found that fluoride increased JNK phosphorylation level of BV-2 cells and pretreatment with JNK inhibitor SP600125 markedly reduced the levels of intracellular O2 ·− and NO. NOX inhibitor apocynin and iNOS inhibitor SMT dramatically decreased NaF-induced ROS and NO generations, respectively. Antioxidant melatonin (MEL) resulted in a reduction in JNK phosphorylation in fluoride-stimulated BV-2 microglia. The results confirmed that NOX and iNOS played an important role in fluoride inducing oxidative stress and NO production and JNK took part in the oxidative stress induced by fluoride and meanwhile also could be activated by ROS in fluoride-treated BV-2 cells. PMID:24072958

GLP-1 Treatment Improves Diabetic Retinopathy by Alleviating Autophagy through GLP-1R-ERK1/2-HDAC6 Signaling Pathway.

PubMed

Cai, Xiangsheng; Li, Jingjing; Wang, Mingzhu; She, Miaoqin; Tang, Yongming; Li, Jinlong; Li, Hongwei; Hui, Hongxiang

2017-01-01

Objective: Apoptosis and autophagy of retinal cells, which may be induced by oxidative stress, are tightly associated with the pathogenesis of diabetic retinopathy (DR). The autophagy induced by oxidative stress is considered as excessively stimulated autophagy, which accelerates the progression of DR. This study aims to investigate the protective effect of GLP-1 treatment on alleviating apoptosis and autophagy of retinal cells in type 2 diabetic rats and reveals its possible mechanism. Methods: Type 2 diabetic rats were induced by fed with high sugar, high fat diet and followed with streptozotocin injection. GLP-1 was applied to treat the diabetic rats for one week after the onset of diabetes. The expressions of oxidative stress-related enzymes, retinal GLP-1R, mitochondria-dependent apoptosis- related genes, autophagy markers, and autophagy-associated pathway genes were studied by Western blotting or immunohistochemistry analysis. Results: GLP-1treatment reduced the levels of NOX3 and SOD2 in DR. The expression of BCL2 was increased, while the levels of caspase3 and LC3B were reduced through GLP-1 treatment in DR . GLP-1 treatment restored the GLP-1R expression and decreased the levels of phosphorylated AKT and phosphorylated ERK1/2, which was accompanied with the reduction of the HDAC6 levels in DR. Conclusions: GLP-1 treatment can alleviate autophagy which may be induced by oxidative stress; this protective effect is likely through GLP-1R-ERK1/2-HDAC6 signaling pathway.

Urea-induced ROS cause endothelial dysfunction in chronic renal failure.

PubMed

D'Apolito, Maria; Du, Xueliang; Pisanelli, Daniela; Pettoello-Mantovani, Massimo; Campanozzi, Angelo; Giacco, Ferdinando; Maffione, Angela Bruna; Colia, Anna Laura; Brownlee, Michael; Giardino, Ida

2015-04-01

The pathogenic events responsible for accelerated atherosclerosis in patients with chronic renal failure (CRF) are poorly understood. Here we investigate the hypothesis that concentrations of urea associated with CRF and increased ROS production in adipocytes might also increase ROS production directly in arterial endothelial cells, causing the same pathophysiologic changes seen with hyperglycemia. Primary cultures of human aortic endothelial cells (HAEC) were exposed to 20mM urea for 48 h. C57BL/6J wild-type mice underwent 5/6 nephrectomy or a sham operation. Randomized groups of 5/6 nephrectomized mice and their controls were also injected i.p. with a SOD/catalase mimetic (MnTBAP) for 15 days starting immediately after the final surgical procedure. Urea at concentrations seen in CRF induced mitochondrial ROS production in cultured HAEC. Urea-induced ROS caused the activation of endothelial pro-inflammatory pathways through the inhibition of GAPDH, including increased protein kinase C isoforms activity, increased hexosamine pathway activity, and accumulation of intracellular AGEs (advanced glycation end products). Urea-induced ROS directly inactivated the anti-atherosclerosis enzyme PGI2 synthase and also caused ER stress. Normalization of mitochondrial ROS production prevented each of these effects of urea. In uremic mice, treatment with MnTBAP prevented aortic oxidative stress, PGI2 synthase activity reduction and increased expression of the pro-inflammatory proteins TNFα, IL-6, VCAM1, Endoglin, and MCP-1. Taken together, these data show that urea itself, at levels common in patients with CRF, causes endothelial dysfunction and activation of proatherogenic pathways. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effect of hypothermia on doxorubicin-induced cardiac myoblast signaling and cell death.

PubMed

L'Ecuyer, Thomas J; Aggarwal, Sanjeev; Zhang, Jiang Ping; Van der Heide, Richard S

2012-01-01

Anthracyclines (AC) are useful chemotherapeutic agents whose principal limitation is cardiac toxicity, which may progress to heart failure, transplantation or even death. We have shown that this toxicity involves oxidative stress-induced activation of the DNA damage pathway. Hypothermia has been shown to be protective against other diseases involving oxidative stress but has not been studied in models of AC toxicity. In the current experiments, H9C2 cardiac myoblasts were treated with varying concentrations of the AC doxorubicin (DOX) during normothermia (37°C) or mild hypothermia (35°C). Total cell death was assayed using trypan blue exclusion and apoptosis by terminal deoxynucleotidyl transferase-mediated deoxyuridine-biotin nick end labeling (TUNEL) staining. Oxidative stress was assayed using the fluorescent indicator 2'7'-dichlorofluorescein diacetate. DNA damage pathway activation was assayed by immunostaining for H2AX and p53. Mitochondrial membrane potential was assayed by JC-1 staining. At all concentrations of DOX examined (1, 2.5 and 5 μM), hypothermia reduced oxidative stress, activation of H2AX and p53, loss of mitochondrial membrane potential and total and apoptotic cell death (P=.001-.03 for each observation). The reduction of oxidative stress-induced activation of the DNA damage pathway and consequent cell death by mild hypothermia supports a possible protective role to reduce the clinical impact of DOX-induced cardiac toxicity. Such an approach may allow expanded use of these effective chemotherapeutic agents to increase cancer cure rates. Copyright © 2012 Elsevier Inc. All rights reserved.

Curcumin attenuates cardiomyocyte hypertrophy induced by high glucose and insulin via the PPARγ/Akt/NO signaling pathway.

PubMed

Chen, Rongchun; Peng, Xiaofeng; Du, Weimin; Wu, Yang; Huang, Bo; Xue, Lai; Wu, Qin; Qiu, Hongmei; Jiang, Qingsong

2015-05-01

To investigate the potential effect of curcumin on cardiomyocyte hypertrophy and a possible mechanism involving the PPARγ/Akt/NO signaling pathway in diabetes. The cardiomyocyte hypertrophy induced by high glucose (25.5mmol/L) and insulin (0.1μmol/L) (HGI) and the antihypertrophic effect of curcumin were evaluated in primary culture by measuring the cell surface area, protein content and atrial natriuretic factor (ANF) mRNA expression. The mRNA and protein expressions were assayed by reverse transcription PCR and Western blotting, whereas the NO concentration and endothelial NO synthase (eNOS) activity were determined using nitrate reduction and ELISA methods, respectively. The cardiomyocyte hypertrophy induced by HGI was characterized by increasing ANF mRNA expression, total protein content, and cell surface area, with downregulated mRNA and protein expressions of both PPARγ and Akt, which paralleled the declining eNOS mRNA expression, eNOS content, and NO concentration. The effects of HGI were inhibited by curcumin (1, 3, 10μmol/L) in a concentration-dependent manner. GW9662 (10μmol/L), a selective PPARγ antagonist, could abolish the effects of curcumin. LY294002 (20μmol/L), an Akt blocker, and N(G)-nitro-l-arginine-methyl ester (100μmol/L), a NOS inhibitor, could also diminish the effects of curcumin. The results suggested that curcumin supplementation can improve HGI-induced cardiomyocytes hypertrophy in vitro through the activation of PPARγ/Akt/NO signaling pathway. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

RhoA/ROCK may involve in cardiac hypertrophy induced by experimental hyperthyroidism.

PubMed

Na, Wang; Peng, Guan; Jianping, Zhang; Yanzhong, Chang; Shengjiang, Guan; Li, Chu

2012-10-01

In this study, the role of the RhoA/Rho-kinase (RhoA/ROCK)-signaling pathway in cardiovascular dysfunction associated with hyperthyroidism was examined with the use of fasudil, a Rho-kinase inhibitor. Male Spraque-Dawley rats were treated with l-thyroxine (T(4)) alone, T(4) + low-dose fasudil (2 mg/kg/day) or T(4) + high-dose fasudil (10 mg/kg/day) and compared with control animals. Rats in the T(4) group showed an increase in the ratio of heart weight to body weight, which was ameliorated by fasudil at both low and high doses. Morphometric and hemodynamic parameters were also evaluated and confirmed that fasudil attenuated the cardiac hypertrophy induced by T(4). The extent of phosphorylation of the myosin phosphatase targeting subunit was quantified by Western blotting to evaluate the activity of Rho-kinase in the heart tissue. Both Western blotting and reverse transcriptase-polymerase chain reaction analyses revealed enhancement of Rho-kinase and activator protein 1 activity and reduction of c-FLIP(L) expression in the T(4) group, and this response was inhibited by fasudil in a dose-dependent manner. Furthermore, fasudil inhibited apoptosis induced by T(4) as evidenced by the detection of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and the expressions of bax and bcl-2. These results suggested that the RhoA/ROCK pathway is involved in the cardiac hypertrophy induced by experimental hyperthyroidism. The antagonism of this pathway may thus be useful as an alternative target in the treatment of hyperthyroid heart disease.

Terminalia arjuna prevents Interleukin-18-induced atherosclerosis via modulation of NF-κB/PPAR-γ-mediated pathway in Apo E-/- mice.

PubMed

Bhat, Owais Mohammad; Kumar, P Uday; Rao, K Rajender; Ahmad, Ashfaq; Dhawan, Veena

2018-04-01

Terminalia arjuna is a medicinal plant well known as a cardiotonic in Ayurvedic system of medicine. We hypothesized that aqueous stem bark extract of T. arjuna (TAE) may inhibit IL-18-induced atherosclerosis via NF-κB/PPAR-γ-mediated pathway in Apo E-/- mice. 12-week-old, male Apo E-/- mice divided into four groups (n = 6/group) fed with normal chow-diet were employed: GP I: phosphate buffer saline (PBS) (2 month); GP II: rIL-18 (1 month) followed by PBS (1 month); GP III: rIL-18 (1 month) followed by TAE (1 month); GP IV: rIL-18 (1 month) followed by atorvastatin (1 month). IL-18 treatment induced a significant increase (p < 0.001) in pro-inflammatory marker (IL-18) (170 ± 9.16 vs. 1178.66 ± 8.08, pg/ml), and downregulated cholesterol efflux gene (PPAR-γ) by ~0.6-fold vs. 1.00 in IL-18-treated mice as compared to the control animals, respectively. TAE treatment to both groups caused a significant reduction in IL-18 to 281.66 ± 9.60 vs. 1178.66 ± 8.08 (pg/ml), upregulated cholesterol efflux gene by ~1.5- vs. 0.6-fold in TAE-treated group, decreased atherogenic lipids, and percentage atherosclerotic lesion area, demonstrating comparable effects with atorvastatin. Our data demonstrate that TAE protects against IL-18-induced atherosclerosis via NF-κB/PPAR-γ-mediated pathway.

Duodeno-jejunal bypass restores β-cell hypersecretion and islet hypertrophy in western diet obese rats.

PubMed

Mendes, Mariana Carla; Bonfleur, Maria Lúcia; Ribeiro, Rosane Aparecida; Lubaczeuski, Camila; Fêo, Ana Flavia Justino; Vargas, Rodrigo; Carneiro, Everardo Magalhães; Boschero, Antonio Carlos; Araujo, Allan Cezar Faria; Balbo, Sandra Lucinei

2018-06-01

Duodeno-jejunal bypass (DJB) operation improves glucose homeostasis in morbid obesity, independently of weight loss or reductions in adiposity, through mechanisms not yet fully elucidated. Herein, we evaluated the effects of DJB upon glucose homeostasis, endocrine pancreatic morphology, and β-cell responsiveness to potentiating agents of cholinergic and cAMP pathways, in western diet (WD) obese rats, at 2 months after operation. From 8 to 18 weeks of age male Wistar rats fed on a WD. After this period, a sham (WD Sham group) or DJB (WD DJB) operations were performed. At 2 months after operation glucose homeostasis was verified. Body weight was similar between WD DJB and WD Sham rats, but WD DJB rats showed a decrease in Lee index, retroperitoneal and perigonadal fat pads. Also, WD DJB rats displayed reduced fasting glycemia and insulinemia, and increased insulin-induced Akt activation in the gastrocnemius. Islets from WD DJB rats secreted less amounts of insulin, in response to activators of the cholinergic (carbachol and phorbol 12-myristate 13-acetate) and cAMP (forskolin and 3-isobutyl-1-methyl-xantine) pathways. Islets of WD DJB rats had higher sintaxin-1 protein content than WD Sham, but without modification in muscarinic-3 receptor, protein kinase (PK)-Cα, and (PK)-Aα protein amounts. In addition, islets of WD DJB animals showed reduction in islets and β-cell masses. DJB surgery improves fasting glycemia and insulin action in skeletal muscle. Better endocrine pancreatic morphofunction was associated, at least in part, with the regulation of the cholinergic and cAMP pathways, and improvements in syntaxin-1 islet protein content induced by DJB.

Prokineticin-1 (PROK1) modulates interleukin (IL)-11 expression via prokineticin receptor 1 (PROKR1) and the calcineurin/NFAT signalling pathway.

PubMed

Cook, Ian H; Evans, Jemma; Maldonado-Pérez, David; Critchley, Hilary O; Sales, Kurt J; Jabbour, Henry N

2010-03-01

Prokineticin-1 (PROK1) is a multifunctional secreted protein which signals via the G-protein coupled receptor, PROKR1. Previous data from our laboratory using a human genome survey microarray showed that PROK1-prokineticin receptor 1 (PROKR1) signalling regulates numerous genes important for establishment of early pregnancy, including the cytokine interleukin (IL)-11. Here, we have shown that PROK1-PROKR1 induces the expression of IL-11 in PROKR1 Ishikawa cells and first trimester decidua via the calcium-calcineurin signalling pathway in a guanine nucleotide-binding protein (G(q/11)), extracellular signal-regulated kinases, Ca(2+) and calcineurin-nuclear factor of activated T cells dependent manner. Conversely, treatment of human decidua with a lentiviral miRNA to abolish endogenous PROK1 expression results in a significant reduction in IL-11 expression and secretion. Importantly, we have also shown a regulatory role for the regulator of calcineurin 1 isoform 4 (RCAN1-4). Overexpression of RCAN1-4 in PROKR1 Ishikawa cells using an adenovirus leads to a reduction in PROK1 induced IL-11 indicating that RCAN1-4 is a negative regulator in the calcineurin-mediated signalling to IL-11. Finally, we have shown the potential for both autocrine and paracrine signalling in the human endometrium by co-localizing IL-11, IL-11Ralpha and PROKR1 within the stromal and glandular epithelial cells of non-pregnant endometrium and first trimester decidua. Overall we have identified and characterized the signalling components of a novel PROK1-PROKR1 signalling pathway regulating IL-11.

Prokineticin-1 (PROK1) modulates interleukin (IL)-11 expression via prokineticin receptor 1 (PROKR1) and the calcineurin/NFAT signalling pathway

PubMed Central

Cook, Ian H.; Evans, Jemma; Maldonado-Pérez, David; Critchley, Hilary O.; Sales, Kurt J.; Jabbour, Henry N.

2010-01-01

Prokineticin-1 (PROK1) is a multifunctional secreted protein which signals via the G-protein coupled receptor, PROKR1. Previous data from our laboratory using a human genome survey microarray showed that PROK1–prokineticin receptor 1 (PROKR1) signalling regulates numerous genes important for establishment of early pregnancy, including the cytokine interleukin (IL)-11. Here, we have shown that PROK1–PROKR1 induces the expression of IL-11 in PROKR1 Ishikawa cells and first trimester decidua via the calcium–calcineurin signalling pathway in a guanine nucleotide-binding protein (Gq/11), extracellular signal-regulated kinases, Ca2+ and calcineurin–nuclear factor of activated T cells dependent manner. Conversely, treatment of human decidua with a lentiviral miRNA to abolish endogenous PROK1 expression results in a significant reduction in IL-11 expression and secretion. Importantly, we have also shown a regulatory role for the regulator of calcineurin 1 isoform 4 (RCAN1-4). Overexpression of RCAN1-4 in PROKR1 Ishikawa cells using an adenovirus leads to a reduction in PROK1 induced IL-11 indicating that RCAN1-4 is a negative regulator in the calcineurin-mediated signalling to IL-11. Finally, we have shown the potential for both autocrine and paracrine signalling in the human endometrium by co-localizing IL-11, IL-11Rα and PROKR1 within the stromal and glandular epithelial cells of non-pregnant endometrium and first trimester decidua. Overall we have identified and characterized the signalling components of a novel PROK1–PROKR1 signalling pathway regulating IL-11. PMID:19801577

Soybean Aphid Infestation Induces Changes in Fatty Acid Metabolism in Soybean

PubMed Central

Kanobe, Charles; McCarville, Michael T.; O’Neal, Matthew E.; Tylka, Gregory L.; MacIntosh, Gustavo C.

2015-01-01

The soybean aphid (Aphis glycines Matsumura) is one of the most important insect pests of soybeans in the North-central region of the US. It has been hypothesized that aphids avoid effective defenses by inhibition of jasmonate-regulated plant responses. Given the role fatty acids play in jasmonate-induced plant defenses, we analyzed the fatty acid profile of soybean leaves and seeds from aphid-infested plants. Aphid infestation reduced levels of polyunsaturated fatty acids in leaves with a concomitant increase in palmitic acid. In seeds, a reduction in polyunsaturated fatty acids was associated with an increase in stearic acid and oleic acid. Soybean plants challenged with the brown stem rot fungus or with soybean cyst nematodes did not present changes in fatty acid levels in leaves or seeds, indicating that the changes induced by aphids are not a general response to pests. One of the polyunsaturated fatty acids, linolenic acid, is the precursor of jasmonate; thus, these changes in fatty acid metabolism may be examples of “metabolic hijacking” by the aphid to avoid the induction of effective defenses. Based on the changes in fatty acid levels observed in seeds and leaves, we hypothesize that aphids potentially induce interference in the fatty acid desaturation pathway, likely reducing FAD2 and FAD6 activity that leads to a reduction in polyunsaturated fatty acids. Our data support the idea that aphids block jasmonate-dependent defenses by reduction of the hormone precursor. PMID:26684003

On the Mechanism of Serotonin-Induced Dipsogenesis in the Rat

NASA Technical Reports Server (NTRS)

Kikta, Dianne C.; Barney, Christopher C.; Threatte, Rose M.; Fregly, Melvin J.; Rowland, Neil E.; Greenleaf, John E.

1983-01-01

Subcutaneous administration of 1-5-hydroxytryptophan (5-HTP), the precursor of serotonin, to female rats induces copious drinking accompanied by activation of the renin-angiotensin system. Neither a reduction in blood pressure nor body temperature accompanied administration of 5-HTP. The objective of the present study was to determine whether serotonin-induced dipsogenesis, like that of 5-HTP, is mediated via the renin-angiotensin system. Serotonin (2 mg/kg, SC)-induced drinking was inhibited by the dopaminergic antagonist, haloperidol (150 /micro g/kg, IP), which also inhibits angiotensin II-induced drinking, Both captopril (35 mg/kg, IP), an angiotensin converting enzyme inhibitor, and propranolol (6 micro g/kg, IP), a beta-adrenergic antagonist, blocked serotonin-induced dipsogenesis. The alpha(sub a),-adrenergic agonist, clonidine (6.25 micro g/kg, SC), which suppresses renin release from the kidney, attenuated serotonin-induced water intake. The dipsogenic responses to submaximal concentrations of both serotonin (1 mg/kg, SC) and isoproterenol (8 micro g/kg, SC) were additive rather than interactive suggesting that similar pathways mediate both responses. The serotonergic receptor antagonist, methysergide (3 mg/kg, IP), inhibited serotonin-induced drinking but had no effect on isoproterenol (25micro g/kg, SC)-induced dipsogenesis. However, neither serotonin (2 mg/kg, SC) nor isoproterenol (25 micro g/kg, SC)-induced drinking was inhibited by cinansefin (25 micro g/kg, IP). These data indicate that serotonin induces drinking in rats via the renin-angiotensin system. However, the results of the studies using methysergide suggest that scrotonin appears to act at a point prior to activation of beta-adrenoceptors in the pathway leading to release of renin from the kidneys.

HIF-inducible miR-191 promotes migration in breast cancer through complex regulation of TGFβ-signaling in hypoxic microenvironment.

PubMed

Nagpal, Neha; Ahmad, Hafiz M; Chameettachal, Shibu; Sundar, Durai; Ghosh, Sourabh; Kulshreshtha, Ritu

2015-04-13

The molecular mechanisms of hypoxia induced breast cell migration remain incompletely understood. Our results show that hypoxia through hypoxia-inducible factor (HIF) brings about a time-dependent increase in the level of an oncogenic microRNA, miR-191 in various breast cancer cell lines. miR-191 enhances breast cancer aggressiveness by promoting cell proliferation, migration and survival under hypoxia. We further established that miR-191 is a critical regulator of transforming growth factor beta (TGFβ)-signaling and promotes cell migration by inducing TGFβ2 expression under hypoxia through direct binding and indirectly by regulating levels of a RNA binding protein, human antigen R (HuR). The levels of several TGFβ pathway genes (like VEGFA, SMAD3, CTGF and BMP4) were found to be higher in miR-191 overexpressing cells. Lastly, anti-miR-191 treatment given to breast tumor spheroids led to drastic reduction in spheroid tumor volume. This stands as a first report of identification of a microRNA mediator that links hypoxia and the TGFβ signaling pathways, both of which are involved in regulation of breast cancer metastasis. Together, our results show a critical role of miR-191 in hypoxia-induced cancer progression and suggest that miR-191 inhibition may offer a novel therapy for hypoxic breast tumors.

Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

PubMed

Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

2016-03-01

Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

Induction of triglyceride accumulation and mitochondrial maintenance in muscle cells by lactate

PubMed Central

Sun, Jingquan; Ye, Xin; Xie, Minhao; Ye, Jianping

2016-01-01

Muscle exercise induces intramuscular triglyceride (TG) accumulation and promotes mitochondrial maintenance in myotubes. However, the mechanism underlying exercise effects remains unknown. In this study, lactic acid was tested as a signaling molecule in C2C12 myotubes to understand the mechanism. Intracellular TG storage was induced in the cells by sodium lactate. The lactate activity was observed with an inhibition of the cAMP-PKA pathway as indicated by a reduction in the phosphorylation status of CREB (pCREB). Induction of pCREB signal by forskolin was blocked by pretreatment of cells with lactate. The impact of lactate on mitochondrial function was examined with a focus on the activities of two enzymes, MCAT (malonylCoA:ACP transferase) and PDH (pyruvate dehydrogenase). The enzyme activities were induced in the cells by lactate. Expression of the lactate receptor (GPR81) and lactate transporters (MCT1/4) were induced as well by lactate. The lactate activities were observed at concentrations between 4–64 mM, and were not dependent on the increase in intracellular pyruvate. Pyruvate treatment did not generate the same effects in the cells. Those results suggest that lactate may induce intramuscular TG storage and mitochondrial maintenance in myotubes through inhibition of the cAMP pathway by activation of GPR81 in a positive feedback manner. PMID:27645401

Syringyl lignin is unaltered by severe sinapyl alcohol dehydrogenase suppression in tobacco.

PubMed

Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N; Marshall, David; Hancock, Robert D; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

2011-12-01

The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference-inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem.

Syringyl Lignin Is Unaltered by Severe Sinapyl Alcohol Dehydrogenase Suppression in Tobacco[W

PubMed Central

Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N.; Marshall, David; Hancock, Robert D.; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

2011-01-01

The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference–inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem. PMID:22158465

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen Ngoc, Tam Dan; Son, Young-Ok; Lim, Shin-Saeng

2012-03-15

Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G{sub 2}/M phase. The addition of NaFmore » induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45α. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-α or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ► The mode of NaF-induced cell death and the mechanisms involved were examined. ► NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ► NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ► JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ► ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.« less

Mercury induces proliferation and reduces cell size in vascular smooth muscle cells through MAPK, oxidative stress and cyclooxygenase-2 pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguado, Andrea; Galán, María; Zhenyukh, Olha

2013-04-15

Mercury exposure is known to increase cardiovascular risk but the underlying cellular mechanisms remain undetermined. We analyzed whether chronic exposure to HgCl{sub 2} affects vascular structure and the functional properties of vascular smooth muscle cells (VSMC) through oxidative stress/cyclooxygenase-2 dependent pathways. Mesenteric resistance arteries and aortas from Wistar rats treated with HgCl{sub 2} (first dose 4.6 mg kg{sup −1}, subsequent doses 0.07 mg kg{sup −1} day{sup −1}, 30 days) and cultured aortic VSMC stimulated with HgCl{sub 2} (0.05–5 μg/ml) were used. Treatment of rats with HgCl{sub 2} decreased wall thickness of the resistance and conductance vasculature, increased the number ofmore » SMC within the media and decreased SMC nucleus size. In VSMCs, exposure to HgCl{sub 2}: 1) induced a proliferative response and a reduction in cell size; 2) increased superoxide anion production, NADPH oxidase activity, gene and/or protein levels of the NADPH oxidase subunit NOX-1, the EC- and Mn-superoxide dismutases and cyclooxygenase-2 (COX-2); 3) induced activation of ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized the proliferative response and the altered cell size induced by HgCl{sub 2}. Blockade of ERK1/2 and p38 signaling pathways abolished the HgCl{sub 2}-induced Nox1 and COX-2 expression and normalized the alterations induced by mercury in cell proliferation and size. In conclusion, long exposure of VSMC to low doses of mercury activates MAPK signaling pathways that result in activation of inflammatory proteins such as NADPH oxidase and COX-2 that in turn induce proliferation of VSMC and changes in cell size. These findings offer further evidence that mercury might be considered an environmental risk factor for cardiovascular disease. - Highlights: ► Chronic HgCl{sub 2} exposure induces vascular remodeling. ► HgCl{sub 2} induces proliferation and decreased cell size in vascular smooth muscle cells. ► HgCl{sub 2} induces MAPK activation, oxidative stress and COX-2 expression. ► Inhibition of MAPK reduces HgCl{sub 2}-induced oxidative stress and COX-2 expression. ► Inhibition of MAPK, oxidative stress and COX-2 restores the altered cell proliferation and size.« less

Grb-2–associated binder 1 (Gab1) regulates postnatal ischemic and VEGF-induced angiogenesis through the protein kinase A–endothelial NOS pathway

PubMed Central

Xiong, Yan; Huo, Yingqing; Han, Jingyan; Yang, Xiao; Zhang, Rongli; Zhu, De-Sheng; Klein-Heßling, Stefan; Zhang, Xiaoyu; Han, Xiaofan; Li, Yanli; Shen, Bin; He, Yulong; Shibuya, Masabumi; Feng, Gen-Sheng; Luo, Jincai

2011-01-01

The intracellular signaling mechanisms underlying postnatal angiogenesis are incompletely understood. Herein we show that Grb-2–associated binder 1 (Gab1) plays a critical role in ischemic and VEGF-induced angiogenesis. Endothelium-specific Gab1 KO (EGKO) mice displayed impaired angiogenesis in the ischemic hindlimb despite normal induction of VEGF expression. Matrigel plugs with VEGF implanted in EGKO mice induced fewer capillaries than those in control mice. The vessels and endothelial cells (ECs) derived from EGKO mice were defective in vascular sprouting and tube formation induced by VEGF. Biochemical analyses revealed a substantial reduction of endothelial NOS (eNOS) activation in Gab1-deficient vessels and ECs following VEGF stimulation. Interestingly, the phosphorylation of Akt, an enzyme known to promote VEGF-induced eNOS activation, was increased in Gab1-deficient vessels and ECs whereas protein kinase A (PKA) activity was significantly decreased. Introduction of an active form of PKA rescued VEGF-induced eNOS activation and tube formation in EGKO ECs. Reexpression of WT or mutant Gab1 molecules in EGKO ECs revealed requirement of Gab1/Shp2 association for the activation of PKA and eNOS. Taken together, these results identify Gab1 as a critical upstream signaling component in VEGF-induced eNOS activation and tube formation, which is dependent on PKA. Of note, this pathway is conserved in primary human ECs for VEGF-induced eNOS activation and tube formation, suggesting considerable potential in treatment of human ischemic diseases. PMID:21282639

Complement Inhibition Alleviates Paraquat-Induced Acute Lung Injury

PubMed Central

Sun, Shihui; Wang, Hanbin; Zhao, Guangyu; An, Yingbo; Guo, Yan; Du, Lanying; Song, Hongbin; Qiao, Fei; Yu, Hong; Wu, Xiaohong; Atkinson, Carl; Jiang, Shibo; Tomlinson, Stephen

2011-01-01

The widely used herbicide, paraquat (PQ), is highly toxic and claims thousands of lives from both accidental and voluntary ingestion. The pathological mechanisms of PQ poisoning–induced acute lung injury (ALI) are not well understood, and the role of complement in PQ-induced ALI has not been elucidated. We developed and characterized a mouse model of PQ-induced ALI and studied the role of complement in the pathogenesis of PQ poisoning. Intraperitoneal administration of PQ caused dose- and time-dependent lung damage and mortality, with associated inflammatory response. Within 24 hours of PQ-induced ALI, there was significantly increased expression of the complement proteins, C1q and C3, in the lung. Expression of the anaphylatoxin receptors, C3aR and C5aR, was also increased. Compared with wild-type mice, C3-deficient mice survived significantly longer and displayed significantly reduced lung inflammation and pathology after PQ treatment. Similar reductions in PQ-induced inflammation, pathology, and mortality were recorded in mice treated with the C3 inhibitors, CR2-Crry, and alternative pathway specific CR2-fH. A similar therapeutic effect was also observed by treatment with either C3a receptor antagonist or a blocking C5a receptor monoclonal antibody. Together, these studies indicate that PQ-induced ALI is mediated through receptor signaling by the C3a and C5a complement activation products that are generated via the alternative complement pathway, and that complement inhibition may be an effective clinical intervention for postexposure treatment of PQ-induced ALI. PMID:21421909

Parallel pathways of potassium transport in the alga Hydrodictyon reticulatum. Effects of calcium.

PubMed

Nespůrková, L; Rybová, R; Janácek, K

1987-06-01

Inflow of potassium ions into the alga Hydrodictyon reticulatum is reduced in the dark, the reduction being accompanied by a change in the selectivity pattern with respect to alkali metal ions, observed in competition experiments and evaluated by the gnostic analysis as described by Kovanic. This suggests that in the light a special mechanism of potassium uptake with a characteristic selectivity is switched on. This mechanism can be also suppressed by too high (2 mmol/l) or too low (EGTA) concentration of calcium ions in the medium. Since the same applies to the light-induced alkalinization of the algal surroundings it seems that the light-induced potassium uptake is related to the light-induced alkalinization, e.g., via exchange of external potassium cations for intracellular protons.

PPARα, PPARγ and SREBP-1 pathways mediated waterborne iron (Fe)-induced reduction in hepatic lipid deposition of javelin goby Synechogobius hasta.

PubMed

Chen, Guang-Hui; Luo, Zhi; Chen, Feng; Shi, Xi; Song, Yu-Feng; You, Wen-Jing; Liu, Xu

2017-07-01

The 42-day experiment was conducted to investigate the effects and mechanism of waterborne Fe exposure influencing hepatic lipid deposition in Synechogobius hasta. For that purpose, S. hasta were exposed to four Fe concentrations (0 (control), 0.36, 0.72 and 1.07μM Fe) for 42days. On days 21 and 42, morphological parameters, hepatic lipid deposition and Fe contents, and activities and mRNA levels of enzymes and genes related to lipid metabolism, including lipogenic enzymes (6PGD, G6PD, ME, ICDH, FAS and ACC) and lipolytic enzymes (CPTI, HSL), were analyzed. With the increase of Fe concentration, hepatic Fe content tended to increase but HSI and lipid content tended to decrease. On day 21, Fe exposure down-regulated the lipogenic activities of 6PGD, G6PD, ICDH and FAS as well as the mRNA levels of G6PD, ACCa, FAS, SREBP-1 and PPARγ, but up-regulated CPT I, HSLa and PPARα mRNA levels. On day 42, Fe exposure down-regulated the lipogenic activities of 6PGD, G6PD, ICDH and FAS as well as the mRNA levels of 6PGD, ACCa, FAS and SREBP-1, but up-regulated CPT I, HSLa, PPARα and PPARγ mRNA levels. Using primary S. hasta hepatocytes, specific pathway inhibitors (GW6471 for PPARα and fatostatin for SREBP-1) and activator (troglitazone for PPARγ) were used to explore the signaling pathways of Fe reducing lipid deposition. The GW6471 attenuated the Fe-induced down-regulation of mRNA levels of 6PGD, G6PD, ME, FAS and ACCa, and attenuated the Fe-induced up-regulation of mRNA levels of CPT I, HSLa and PPARα. Compared with single Fe-incubated group, the mRNA levels of G6PD, ME, FAS, ACCa, ACCb and PPARγ were up-regulated while the CPT I mRNA levels were down-regulated after troglitazone pre-treatment; fatostatin pre-treatment down-regulated the mRNA levels of 6PGD, ME, FAS, ACCa, ACCb and SREBP-1, and increased the CPT I and HSLa mRNA levels. Based on these results above, our study indicated that Fe exposure reduced hepatic lipid deposition by down-regulating lipogenesis and up-regulating lipolysis, and PPARα, PPARγ and SREBP-1 pathways mediated the Fe-induced reduction of hepatic lipid deposition in S. hasta. Copyright © 2017 Elsevier Inc. All rights reserved.

Drug-Path: a database for drug-induced pathways

PubMed Central

Zeng, Hui; Cui, Qinghua

2015-01-01

Some databases for drug-associated pathways have been built and are publicly available. However, the pathways curated in most of these databases are drug-action or drug-metabolism pathways. In recent years, high-throughput technologies such as microarray and RNA-sequencing have produced lots of drug-induced gene expression profiles. Interestingly, drug-induced gene expression profile frequently show distinct patterns, indicating that drugs normally induce the activation or repression of distinct pathways. Therefore, these pathways contribute to study the mechanisms of drugs and drug-repurposing. Here, we present Drug-Path, a database of drug-induced pathways, which was generated by KEGG pathway enrichment analysis for drug-induced upregulated genes and downregulated genes based on drug-induced gene expression datasets in Connectivity Map. Drug-Path provides user-friendly interfaces to retrieve, visualize and download the drug-induced pathway data in the database. In addition, the genes deregulated by a given drug are highlighted in the pathways. All data were organized using SQLite. The web site was implemented using Django, a Python web framework. Finally, we believe that this database will be useful for related researches. Database URL: http://www.cuilab.cn/drugpath PMID:26130661

Drug-Path: a database for drug-induced pathways.

PubMed

Zeng, Hui; Qiu, Chengxiang; Cui, Qinghua

2015-01-01

Some databases for drug-associated pathways have been built and are publicly available. However, the pathways curated in most of these databases are drug-action or drug-metabolism pathways. In recent years, high-throughput technologies such as microarray and RNA-sequencing have produced lots of drug-induced gene expression profiles. Interestingly, drug-induced gene expression profile frequently show distinct patterns, indicating that drugs normally induce the activation or repression of distinct pathways. Therefore, these pathways contribute to study the mechanisms of drugs and drug-repurposing. Here, we present Drug-Path, a database of drug-induced pathways, which was generated by KEGG pathway enrichment analysis for drug-induced upregulated genes and downregulated genes based on drug-induced gene expression datasets in Connectivity Map. Drug-Path provides user-friendly interfaces to retrieve, visualize and download the drug-induced pathway data in the database. In addition, the genes deregulated by a given drug are highlighted in the pathways. All data were organized using SQLite. The web site was implemented using Django, a Python web framework. Finally, we believe that this database will be useful for related researches. © The Author(s) 2015. Published by Oxford University Press.

3'-Geranyl-mono-substituted chalcone Xanthoangelovl induces apoptosis in human leukemia K562 cells via activation of mitochondrial pathway.

PubMed

Teng, Yuou; Wang, Lixin; Liu, Huan; Yuan, Yuan; Zhang, Qian; Wu, Meng; Wang, Luyao; Wang, Haomeng; Liu, Zhen; Yu, Peng

2017-01-05

3'-Geranyl-mono-substituted chalcone Xanthoangelol (1b), a chalcone derivative, was previously reported to show selective cytotoxicity against human chronic myelogenous leukemia K562 cells with a half-maximal inhibitory concentration (IC 50 ) of 3.98 μM. In the present study, we investigated the molecular mechanism underlying the cytotoxicity of 1b in K562 cells. Treatment with compound 1b caused K562 cells to adopt a typical apoptotic morphology. Flow cytometric analysis also confirmed the presence of an apoptotic cell population following treatment of Annexin-V-FITC and propidium iodide (PI) double-labeled K562 cells with 1b. Furthermore, we observed dissipation of the mitochondrial membrane potential, caspase-3 activation, and a reduction of the Bcl-2/Bax ratio in these cells, which suggest that the mitochondrial apoptotic pathway is induced by 1b in K562 cells. Collectively, our findings demonstrate that compound 1b notably induces mitochondrial-mediated apoptosis in K562 cells, which might have a potential anticancer activity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inactivation of virus in solution by cold atmospheric pressure plasma: identification of chemical inactivation pathways

NASA Astrophysics Data System (ADS)

Aboubakr, Hamada A.; Gangal, Urvashi; Youssef, Mohammed M.; Goyal, Sagar M.; Bruggeman, Peter J.

2016-05-01

Cold atmospheric pressure plasma (CAP) inactivates bacteria and virus through in situ production of reactive oxygen and nitrogen species (RONS). While the bactericidal and virucidal efficiency of plasmas is well established, there is limited knowledge about the chemistry leading to the pathogen inactivation. This article describes a chemical analysis of the CAP reactive chemistry involved in the inactivation of feline calicivirus. We used a remote radio frequency CAP produced in varying gas mixtures leading to different plasma-induced chemistries. A study of the effects of selected scavengers complemented with positive control measurements of relevant RONS reveal two distinctive pathways based on singlet oxygen and peroxynitrous acid. The first mechanism is favored in the presence of oxygen and the second in the presence of air when a significant pH reduction is induced in the solution by the plasma. Additionally, smaller effects of the H2O2, O3 and \\text{NO}2- produced were also found. Identification of singlet oxygen-mediated 2-imidazolone/2-oxo-His (His  +14 Da)—an oxidative modification of His 262 comprising the capsid protein of feline calicivirus links the plasma induced singlet oxygen chemistry to viral inactivation.

Direct vs. indirect pathway for nitrobenzene reduction reaction on a Ni catalyst surface: a density functional study.

PubMed

Mahata, Arup; Rai, Rohit K; Choudhuri, Indrani; Singh, Sanjay K; Pathak, Biswarup

2014-12-21

Density functional theory (DFT) calculations are performed to understand and address the previous experimental results that showed the reduction of nitrobenzene to aniline prefers direct over indirect reaction pathways irrespective of the catalyst surface. Nitrobenzene to aniline conversion occurs via the hydroxyl amine intermediate (direct pathway) or via the azoxybenzene intermediate (indirect pathway). Through our computational study we calculated the spin polarized and dispersion corrected reaction energies and activation barriers corresponding to various reaction pathways for the reduction of nitrobenzene to aniline over a Ni catalyst surface. The adsorption behaviour of the substrate, nitrobenzene, on the catalyst surface was also considered and the energetically most preferable structural orientation was elucidated. Our study indicates that the parallel adsorption behaviour of the molecules over a catalyst surface is preferable over vertical adsorption behaviour. Based on the reaction energies and activation barrier of the various elementary steps involved in direct or indirect reaction pathways, we find that the direct reduction pathway of nitrobenzene over the Ni(111) catalyst surface is more favourable than the indirect reaction pathway.

Regulation of Survival Motor Neuron Protein by the Nuclear Factor-Kappa B Pathway in Mouse Spinal Cord Motoneurons.

PubMed

Arumugam, Saravanan; Mincheva-Tasheva, Stefka; Periyakaruppiah, Ambika; de la Fuente, Sandra; Soler, Rosa M; Garcera, Ana

2018-06-01

Survival motor neuron (SMN) protein deficiency causes the genetic neuromuscular disorder spinal muscular atrophy (SMA), characterized by spinal cord motoneuron degeneration. Since SMN protein level is critical to disease onset and severity, analysis of the mechanisms involved in SMN stability is one of the central goals of SMA research. Here, we describe the role of several members of the NF-κB pathway in regulating SMN in motoneurons. NF-κB is one of the main regulators of motoneuron survival and pharmacological inhibition of NF-κB pathway activity also induces mouse survival motor neuron (Smn) protein decrease. Using a lentiviral-based shRNA approach to reduce the expression of several members of NF-κB pathway, we observed that IKK and RelA knockdown caused Smn reduction in mouse-cultured motoneurons whereas IKK or RelB knockdown did not. Moreover, isolated motoneurons obtained from the severe SMA mouse model showed reduced protein levels of several NF-κB members and RelA phosphorylation. We describe the alteration of NF-κB pathway in SMA cells. In the context of recent studies suggesting regulation of altered intracellular pathways as a future pharmacological treatment of SMA, we propose the NF-κB pathway as a candidate in this new therapeutic approach.

Blockade of the receptor for advanced glycation end products attenuates acetaminophen-induced hepatotoxicity in mice.

PubMed

Ekong, Udeme; Zeng, Shan; Dun, Hao; Feirt, Nikki; Guo, Jiancheng; Ippagunta, Nikalesh; Guarrera, James V; Lu, Yan; Weinberg, Alan; Qu, Wu; Ramasamy, Ravichandran; Schmidt, Ann Marie; Emond, Jean C

2006-04-01

Severe injury to the liver, such as that induced by toxic doses of acetaminophen, triggers a cascade of events leading to hepatocyte death. It is hypothesized that activation of the receptor for advanced glycation end products (RAGE) might contribute to acetaminophen-induced liver toxicity by virtue of its ability to generate reactive oxygen species, at least in part via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and thereby activate downstream signaling pathways leading to cellular injury. A model was employed in which toxic doses of acetaminophen (1125 mg/kg) were administered to C57BL/6 mice. To block RAGE, mice received murine soluble (s) RAGE, the extracellular ligand binding domain of the receptor that acts as a decoy to interrupt ligand-RAGE signaling. Animals treated with sRAGE displayed increased survival compared with vehicle treatment, and markedly decreased hepatic necrosis. Consistent with an important role for RAGE-triggered oxidant stress in acetaminophen-induced injury, a significant reduction of nitrotyrosine protein adducts was observed in hepatic tissue in sRAGE-treated versus vehicle-treated mice receiving acetaminophen, in parallel with significantly increased levels of glutathione. In addition, pro-regenerative cytokines tumor necrosis factor-alpha and interleukin-6 were increased in sRAGE-treated versus vehicle-treated mice. These findings implicate RAGE-dependent mechanisms in acetaminophen-induced liver damage and suggest that blockade of this pathway may impart beneficial effects in toxin-induced liver injury.

RanBP9 at the intersection between cofilin and Aβ pathologies: rescue of neurodegenerative changes by RanBP9 reduction.

PubMed

Woo, J A; Boggess, T; Uhlar, C; Wang, X; Khan, H; Cappos, G; Joly-Amado, A; De Narvaez, E; Majid, S; Minamide, L S; Bamburg, J R; Morgan, D; Weeber, E; Kang, D E

2015-03-05

Molecular pathways underlying the neurotoxicity and production of amyloid β protein (Aβ) represent potentially promising therapeutic targets for Alzheimer's disease (AD). We recently found that overexpression of the scaffolding protein RanBP9 increases Aβ production in cell lines and in transgenic mice while promoting cofilin activation and mitochondrial dysfunction. Translocation of cofilin to mitochondria and induction of cofilin-actin pathology require the activation/dephosphorylation of cofilin by Slingshot homolog 1 (SSH1) and cysteine oxidation of cofilin. In this study, we found that endogenous RanBP9 positively regulates SSH1 levels and mediates Aβ-induced translocation of cofilin to mitochondria and induction of cofilin-actin pathology in cultured cells, primary neurons, and in vivo. Endogenous level of RanBP9 was also required for Aβ-induced collapse of growth cones in immature neurons (days in vitro 9 (DIV9)) and depletion of synaptic proteins in mature neurons (DIV21). In vivo, amyloid precursor protein (APP)/presenilin-1 (PS1) mice exhibited 3.5-fold increased RanBP9 levels, and RanBP9 reduction protected against cofilin-actin pathology, synaptic damage, gliosis, and Aβ accumulation associated with APP/PS1 mice. Brains slices derived from APP/PS1 mice showed significantly impaired long-term potentiation (LTP), and RanBP9 reduction significantly enhanced paired pulse facilitation and LTP, as well as partially rescued contextual memory deficits associated with APP/PS1 mice. Therefore, these results underscore the critical importance of endogenous RanBP9 not only in Aβ accumulation but also in mediating the neurotoxic actions of Aβ at the level of synaptic plasticity, mitochondria, and cofilin-actin pathology via control of the SSH1-cofilin pathway in vivo.

Effect of chromium picolinate on modified forced swimming test in diabetic rats: involvement of serotonergic pathways and potassium channels.

PubMed

Khanam, Razia; Pillai, K K

2006-02-01

Depression occurs frequently in patients with diabetes mellitus. Chromium picolinate, an essential trace element is recommended for diabetes and also has been reported to benefit depression, but its mechanism is still debated. To investigate the mechanism, we studied its effects on serum insulin, serum glucose and on modified forced swimming test, a behavioural paradigm for depression in rats. The study involving co-administration of sub-active doses of glimepiride, a K(+) channel blocker and chromium picolinate on blood glucose levels and modified forced swimming test was also performed to probe any role of K(+) channels in its antidiabetic and antidepressants effects. Streptozotocin (55 mg/kg, intraperitoneally) was injected in rats to induce diabetes (Type 1). After a week, chromium picolinate (8 microg/ml in drinking water) was administered for 4 weeks. Normal rats received similar drug treatment. The sub-active doses of chromium picolinate (4 microg/ml in drinking water) and glimeperide (2.5 mg/kg, orally) were co-administered and their effects on modified forced swimming test and on glucose levels were measured. Chromium picolinate (8 microg/ml in drinking water) produced hypoglycaemia in diabetic and normal rats. It had no effects on the streptozotocin-induced reduction in insulin levels. Chromium picolinate (8 microg/ml in drinking water) increased swimming with subsequent decrease in immobility. The sub-active doses of chromium picolinate and glimeperide showed significant additive effects in modified forced swimming test and reduction in serum glucose concentrations, though statistically insignificant. In conclusion chromium picolinate shows antidepressant action on modified forced swimming test affecting only swimming that suggests serotonergic pathways involvement. The additive effects on swimming in modified forced swimming test and reduction in serum glucose levels shows involvement of K(+) channels in antidiabetic and antidepressant actions of chromium picolinate.

Polychlorinated biphenyls (PCB 101, PCB 153 and PCB 180) alter leptin signaling and lipid metabolism in differentiated 3T3-L1 adipocytes.

PubMed

Ferrante, Maria C; Amero, Paola; Santoro, Anna; Monnolo, Anna; Simeoli, Raffaele; Di Guida, Francesca; Mattace Raso, Giuseppina; Meli, Rosaria

2014-09-15

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) are highly lipophilic environmental contaminants that accumulate in lipid-rich tissues, such as adipose tissue. Here, we reported the effects induced by PCBs 101, 153 and 180, three of the six NDL-PCBs defined as indicators, on mature 3T3-L1 adipocytes. We observed an increase in lipid content, in leptin gene expression and a reduction of leptin receptor expression and signaling, when cells were exposed to PCBs, alone or in combination. These modifications were consistent with the occurrence of "leptin-resistance" in adipose tissue, a typical metabolic alteration related to obesity. Therefore, we investigated how PCBs affect the expression of pivotal proteins involved in the signaling of leptin receptor. We evaluated the PCB effect on the intracellular pathway JAK/STAT, determining the phosphorylation of STAT3, a downstream activator of the transcription of leptin gene targets, and the expression of SOCS3 and PTP1B, two important regulators of leptin resistance. In particular, PCBs 153 and 180 or all PCB combinations induced a significant reduction in pSTAT3/STAT3 ratio and an increase in PTP1B and SOCS3, evidencing an additive effect. The impairment of leptin signaling was associated with the reduction of AMPK/ACC pathway activation, leading to the increase in lipid content. These pollutants were also able to increase the transcription of inflammatory cytokines (IL-6 and TNFα). It is worthy to note that the PCB concentrations used are comparable to levels detectable in human adipose tissue. Our data strongly support the hypothesis that NDL-PCBs may interfere with the lipid metabolism contributing to the development of obesity and related diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparison between neurectomy and botulinum toxin A injection for denervated skeletal muscle.

PubMed

Tsai, Feng-Chou; Hsieh, Ming-Shium; Chou, Chih-Ming

2010-08-01

Neurectomy and botulinum toxin A (BoNT-A) injection cause denervated muscle atrophy, but questions remain about their clinical utility. We investigated time-series alterations of rat muscle weight, functional deficits, signaling pathways, and microscopic structures, to gain an understanding of the clinical implications. Between 2008 and 2009, the maximal calf circumference of patients for calf reduction either by neurectomy or BoNT-A injections were recorded for study. A rat skeletal muscle model was established through repeated or dose-adjusted BoNT-A injections and neurectomy. The survival, apoptosis pathways, functional deficits, and microscopic structures were investigated using Western blot, sciatic functional index (SFI), and transmission electron microscopy (TEM), respectively. The rat muscle weight ratio of the BoNT-A group had recovered to 89.3 +/- 3.8% by week 58, but it never recovered in the neurectomy group. Muscle weight reduction by BoNT-A not only depended on the dose, but additive effects were also obtained through repeated injections. Rat SFI demonstrated rapid recovery in both groups. Molecular expressions showed a coherent and biphasic pattern. p-Akt and apoptosis-inducing factor (AIF) were upregulated significantly, with a peak at 8 weeks in the neurectomy group (p < 0.01), but cleaved caspase-9 and caspase-3 showed no significant changes in either group. TEM findings showed irreversible and reversible inner-structure disruption and sarcomere discontinuity in the neurectomy and BoNT-A groups, respectively. We demonstrated that denervation induced lasting muscle weight and structural changes of different degrees. Muscle weight reduction by BoNT-A was related to frequency and dose. AIF-mediated caspase-independent apoptosis was significantly different for neurectomy and BoNT-A injection.

Delineation of molecular pathways that regulate hepatic PCSK9 and LDL receptor expression during fasting in normolipidemic hamsters

PubMed Central

Wu, Minhao; Dong, Bin; Cao, Aiqin; Li, Hai; Liu, Jingwen

2015-01-01

Background PCSK9 has emerged as a key regulator of serum LDL-C metabolism by promoting the degradation of hepatic LDL receptor (LDLR). In this study, we investigated the effect of fasting on serum PCSK9, LDL-C, and hepatic LDLR expression in hamsters and further delineated the molecular pathways involved in fasting-induced repression of PCSK9 transcription. Results Fasting had insignificant effects on serum total cholesterol and HDL-C levels, but reduced LDL-C, triglyceride and insulin levels. The decrease in serum LDL-C was accompanied by marked reductions of hepatic PCSK9 mRNA and serum PCSK9 protein levels with concomitant increases of hepatic LDLR protein amounts. Fasting produced a profound impact on SREBP1 expression and its transactivating activity, while having modest effects on mRNA expressions of SREBP2 target genes in hamster liver. Although PPARα mRNA levels in hamster liver were elevated by fasting, ligand-induced activation of PPARα with WY14643 compound in hamster primary hepatocytes did not affect PCSK9 mRNA or protein expressions. Further investigation on HNF1α, a critical transactivator of PCSK9, revealed that fasting did not alter its mRNA expression, however, the protein abundance of HNF1α in nuclear extracts of hamster liver was markedly reduced by prolonged fasting. Conclusion Fasting lowered serum LDL-C in hamsters by increasing hepatic LDLR protein amounts via reductions of serum PCSK9 levels. Importantly, our results suggest that attenuation of SREBP1 transactivating activity owing to decreased insulin levels during fasting is primarily responsible for compromised PCSK9 gene transcription, which was further suppressed after prolonged fasting by a reduction of nuclear HNF1α protein abundance. PMID:22954675

Cost-Reduction Roadmap Outlines Two Pathways to Meet DOE Residential Solar

Science.gov Websites

Cost Target for 2030 | News | NREL Cost-Reduction Roadmap Outlines Two Pathways to Meet DOE Residential Solar Cost Target for 2030 News Release: Cost-Reduction Roadmap Outlines Two Pathways to Meet DOE Residential Solar Cost Target for 2030 Installing photovoltaics at the time of roof replacement or as part of

Chemical form of selenium differentially influences DNA repair pathways following exposure to lead nitrate.

PubMed

McKelvey, Shauna M; Horgan, Karina A; Murphy, Richard A

2015-01-01

Lead, an environmental toxin is known to induce a broad range of physiological and biochemical dysfunctions in humans through a number of mechanisms including the deactivation of antioxidants thus leading to generation of reactive oxygen species (ROS) and subsequent DNA damage. Selenium on the other hand has been proven to play an important role in the protection of cells from free radical damage and oxidative stress, though its effects are thought to be form and dose dependent. As the liver is the primary organ required for metabolite detoxification, HepG2 cells were chosen to assess the protective effects of various selenium compounds following exposure to the genotoxic agent lead nitrate. Initially DNA damage was quantified using a comet assay, gene expression patterns associated with DNA damage and signalling were also examined using PCR arrays and the biological pathways which were most significantly affected by selenium were identified. Interestingly, the organic type selenium compounds (selenium yeast and selenomethionine) conferred protection against lead induced DNA damage in HepG2 cells; this is evident by reduction in the quantity of DNA present in the comet tail of cells cultured in their presence with lead. This trend also followed through the gene expression changes noted in DNA damage pathways analysed. These results were in contrast with those of inorganic sodium selenite which promoted lead induced DNA damage evident in both the comet assay results and the gene expression analysis. Over all this study provided valuable insights into the effects which various selenium compounds had on the DNA damage and signalling pathway indicating the potential for using organic forms of selenium such as selenium enriched yeast to protect against DNA damaging agents. Copyright © 2014 Elsevier GmbH. All rights reserved.

Glyphosate-induced oxidative stress in Arabidopsis thaliana affecting peroxisomal metabolism and triggers activity in the oxidative phase of the pentose phosphate pathway (OxPPP) involved in NADPH generation.

PubMed

de Freitas-Silva, Larisse; Rodríguez-Ruiz, Marta; Houmani, Hayet; da Silva, Luzimar Campos; Palma, José M; Corpas, Francisco J

2017-11-01

Glyphosate is a broad-spectrum systemic herbicide used worldwide. In susceptible plants, glyphosate affects the shikimate pathway and reduces aromatic amino acid synthesis. Using Arabidopsis seedlings grown in the presence of 20μM glyphosate, we analyzed H 2 O 2 , ascorbate, glutathione (GSH) and protein oxidation content as well as antioxidant catalase, superoxide dismutase (SOD) and ascorbate-glutathione cycle enzyme activity. We also examined the principal NADPH-generating system components, including glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), NADP-malic enzyme (NADP-ME) and NADP-isocitrate dehydrogenase (NADP-ICDH). Glyphosate caused a drastic reduction in growth parameters and an increase in protein oxidation. The herbicide also resulted in an overall increase in GSH content, antioxidant enzyme activity (catalase and all enzymatic components of the ascorbate-glutathione cycle) in addition to the two oxidative phase enzymes, G6PDH and 6PGDH, in the pentose phosphate pathway involved in NADPH generation. In this study, we provide new evidence on the participation of G6PDH and 6PGDH in the response to oxidative stress induced by glyphosate in Arabidopsis, in which peroxisomal enzymes, such as catalase and glycolate oxidase, are positively affected. We suggest that the NADPH provided by the oxidative phase of the pentose phosphate pathway (OxPPP) should serve to maintain glutathione reductase (GR) activity, thus preserving and regenerating the intracellular GSH pool under glyphosate-induced stress. It is particularly remarkable that the 6PGDH activity was unaffected by pro-oxidant and nitrating molecules such as H 2 0 2 , nitric oxide or peroxynitrite. Copyright © 2017 Elsevier GmbH. All rights reserved.

Mitochondrial Dysfunction in Chemotherapy-Induced Peripheral Neuropathy (CIPN)

PubMed Central

Canta, Annalisa; Pozzi, Eleonora; Carozzi, Valentina Alda

2015-01-01

The mitochondrial dysfunction has a critical role in several disorders including chemotherapy-induced peripheral neuropathies (CIPN). This is due to a related dysregulation of pathways involving calcium signalling, reactive oxygen species and apoptosis. Vincristine is able to affect calcium movement through the Dorsal Root Ganglia (DRG) neuronal mitochondrial membrane, altering its homeostasis and leading to abnormal neuronal excitability. Paclitaxel induces the opening of the mitochondrial permeability transition pore in axons followed by mitochondrial membrane potential loss, increased reactive oxygen species generation, ATP level reduction, calcium release and mitochondrial swelling. Cisplatin and oxaliplatin form adducts with mitochondrial DNA producing inhibition of replication, disruption of transcription and morphological abnormalities within mitochondria in DRG neurons, leading to a gradual energy failure. Bortezomib is able to modify mitochondrial calcium homeostasis and mitochondrial respiratory chain. Moreover, the expression of a certain number of genes, including those controlling mitochondrial functions, was altered in patients with bortezomib-induced peripheral neuropathy. PMID:29056658

Direct β-Alkylation of Aldehydes via Photoredox Organocatalysis

PubMed Central

2015-01-01

Direct β-alkylation of saturated aldehydes has been accomplished by synergistically combining photoredox catalysis and organocatalysis. Photon-induced enamine oxidation provides an activated β-enaminyl radical intermediate, which readily combines with a wide range of Michael acceptors to produce β-alkyl aldehydes in a highly efficient manner. Furthermore, this redox-neutral, atom-economical C–H functionalization protocol can be achieved both inter- and intramolecularly. Mechanistic studies by various spectroscopic methods suggest that a reductive quenching pathway is operable. PMID:24754456

p53-dependent control of cell death by nicastrin: lack of requirement for presenilin-dependent gamma-secretase complex.

PubMed

Pardossi-Piquard, Raphaëlle; Dunys, Julie; Giaime, Emilie; Guillot-Sestier, Marie-Victoire; St George-Hyslop, Peter; Checler, Frédéric; Alves da Costa, Cristine

2009-04-01

Nicastrin (NCT) is a component of the presenilin (PS)-dependent gamma-secretase complexes that liberate amyloid beta-peptides from the beta-Amyloid Precursor Protein. Several lines of evidence indicate that the members of these complexes could also contribute to the control of cell death. Here we show that over-expression of NCT increases the viability of human embryonic kidney (HEK293) cells and decreases staurosporine (STS)- and thapsigargin (TPS)-induced caspase-3 activation in various cell lines from human and neuronal origins by Akt-dependent pathway. NCT lowers p53 expression, transcriptional activity and promoter transactivation and reduces p53 phosphorylation. NCT-associated protection against STS-stimulated cell death was completely abolished by p53 deficiency. Conversely, the depletion of NCT drastically enhances STS-induced caspase-3 activation and p53 pathway and favored p53 nuclear translocation. We examined whether NCT protective function depends on PS-dependent gamma-secretase activity. First, a 29-amino acid deletion known to reduce NCT-dependent amyloid beta-peptide production did not affect NCT-associated protective phenotype. Second, NCT still reduces STS-induced caspase-3 activation in fibroblasts lacking PS1 and PS2. Third, the gamma-secretase inhibitor DFK167 did not affect NCT-mediated reduction of p53 activity. Altogether, our study indicates that NCT controls cell death via phosphoinositide 3-kinase/Akt and p53-dependent pathways and that this function remains independent of the activity and molecular integrity of the gamma-secretase complexes.

Betaine recovers hypothalamic neural injury by inhibiting astrogliosis and inflammation in fructose-fed rats.

PubMed

Li, Jian-Mei; Ge, Chen-Xu; Xu, Min-Xuan; Wang, Wei; Yu, Rong; Fan, Chen-Yu; Kong, Ling-Dong

2015-02-01

Hypothalamic astrogliosis and inflammation cause neural injury, playing a critical role in metabolic syndrome development. This study investigated whether and how fructose caused hypothalamic astrogliosis and inflammation in vivo and in vitro. The inhibitory effects of betaine on hypothalamic neural injury, astrogliosis, and inflammation were explored to address its improvement of fructose-induced metabolic syndrome. Rats or astrocytes were exposed to fructose and then treated with betaine. Neural injury, proinflammatory markers, Toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) pathway, and histone deacetylases 3 (HDAC3) expressions were evaluated. The reduction of pro-opiomelanocortin and melanocortin 4 receptor positive neurons in fructose-fed rats was ameliorated by betaine. Moreover, fructose induced astrogliosis and proinflammatory cytokine production by increasing TLR4, MyD88 (where MyD88 is myeloid differentiation factor 88), and NF-κB expression in rat hypothalamus and astrocytes. HDAC3 overexpression preserved the prolonged inflammation in fructose-stimulated astrocytes by regulating nuclear NF-κB-dependent transcription. Betaine suppressed TLR4/NF-κB pathway activation and HDAC3 expression, contributing to its inhibition of hypothalamic astrogliosis and inflammation in animal and cell models. These findings suggest that betaine inhibits fructose-caused astrogliosis and inflammation by the suppression of TLR4/NF-κB pathway activation and HDAC3 expression to protect against hypothalamic neural injury, which, at least partly, contributes to the improvement of fructose-induced metabolic syndrome. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leukemia-associated gene MLAA-34 reduces arsenic trioxide-induced apoptosis in HeLa cells via activation of the Wnt/β-catenin signaling pathway.

PubMed

Zhang, Pengyu; Zhao, Xuan; Zhang, Wenjuan; He, Aili; Lei, Bo; Zhang, Wanggang; Chen, Yinxia

2017-01-01

Our laboratory previously used the SEREX method in U937 cells and identified a novel leukemia-associated gene MLAA-34, a novel splice variant of CAB39L associated with acute monocytic leukemia, that exhibited anti-apoptotic activities in U937 cells. Whether MLAA-34 has an anti-apoptotic role in other tumor cells has not yet been reported. We explored whether MLAA-34 exhibited anti-apoptotic effects in HeLa cervical cancer cells and the possible mechanism of action. We generated a HeLa cell line stably expressing MLAA-34 and found that MLAA-34 overexpression had no effect on the growth, apoptosis and cell cycle of HeLa cells. However, upon treatment with arsenic trioxide (ATO) to induce apoptosis, the cell viability and colony formation ability of ATO-treated MLAA-34 stable HeLa cells were significantly higher than that of ATO-treated controls, and the apoptosis rate and proportion of G2/M cells also decreased. We found that ATO treatment of HeLa cells resulted in significant decreases in the expression of β-catenin mRNA and protein and the downstream target factors c-Myc, cyclin B1, and cyclin D1 in the Wnt signaling pathway. Notably, ATO-treated MLAA-34 stable HeLa cells showed a significant reduction in the ATO-mediated downregulation of these factors. In addition, MLAA-34 overexpression significantly increased the expression of nuclear β-catenin protein in ATO-treated cells compared with HeLa cells treated only with ATO. Thus, here we have found that the Wnt/β-catenin signaling pathway is involved in ATO-induced apoptosis in HeLa cells. MLAA-34 reduces ATO-induced apoptosis and G2/M arrest, and the anti-apoptotic effect may be achieved by activating the Wnt/β-catenin signaling pathway in HeLa cells.

Tanshinone IIA suppresses lung injury and apoptosis, and modulates protein kinase B and extracellular signal-regulated protein kinase pathways in rats challenged with seawater exposure.

PubMed

Li, Jia-Huan; Xu, Min; Xie, Xiao-Yan; Fan, Qi-Xin; Mu, De-Guang; Zhang, Yong; Cao, Fa-Le; Wang, Yan-Xia; Zhao, Peng-Tao; Zhang, Bo; Jin, Fa-Guang; Li, Zhi-Chao

2011-04-01

1. Tanshinone IIA (TIIA) is one of the main active components of the Chinese herb, Danshen. In the present study, we investigated the role of apoptosis in seawater exposure-induced acute lung injury (ALI), and explored the effects of TIIA on lung injury, apoptosis, and protein kinase B (Akt) and extracellular signal-regulated protein kinase (ERK) pathways in seawater-challenged rats. The rats were randomly divided into four groups: (i) naive group, no drug was given; (ii) TIIA control group, TIIA (50 mg/kg) was given intraperitoneally; (iii) seawater (SW) group, seawater (4 mL/kg) was given; and (iv) TIIA/SW group, TIIA (50 mg/kg) was injected intraperitoneally 10 min after seawater instillation. 2. The results showed that TIIA treatment significantly improved seawater exposure-induced lung histopathological changes, alleviated the decrease in PaO(2) , and reduced lung oedema, vascular leakage and cell infiltration. As shown by terminal deoxynucleotidyl transferase-mediated nick end labelling (TUNEL) assay, seawater exposure induced apoptosis in lung tissue cells. Furthermore, seawater exposure also changed apoptosis-related factors Bcl-2 and caspase-3, and caused a reduction in the activation of Akt and ERK1/2 pathways. Furthermore, TIIA treatment decreased the number of apoptotic cells, reversed changes in Bcl-2 and caspase-3, and upregulated the activation of Akt and ERK1/2 in seawater-challenged rats. 3. In conclusion, the data suggest that apoptosis might play an important role in seawater exposure-induced lung injury and that TIIA could significantly attenuate the severity of ALI and apoptosis in seawater-challenged rats, which is possibly through modulation of Akt and ERK1/2 pathways. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Leukemia-associated gene MLAA-34 reduces arsenic trioxide-induced apoptosis in HeLa cells via activation of the Wnt/β-catenin signaling pathway

PubMed Central

Zhao, Xuan; Zhang, Wenjuan; He, Aili; Lei, Bo; Zhang, Wanggang; Chen, Yinxia

2017-01-01

Our laboratory previously used the SEREX method in U937 cells and identified a novel leukemia-associated gene MLAA-34, a novel splice variant of CAB39L associated with acute monocytic leukemia, that exhibited anti-apoptotic activities in U937 cells. Whether MLAA-34 has an anti-apoptotic role in other tumor cells has not yet been reported. We explored whether MLAA-34 exhibited anti-apoptotic effects in HeLa cervical cancer cells and the possible mechanism of action. We generated a HeLa cell line stably expressing MLAA-34 and found that MLAA-34 overexpression had no effect on the growth, apoptosis and cell cycle of HeLa cells. However, upon treatment with arsenic trioxide (ATO) to induce apoptosis, the cell viability and colony formation ability of ATO-treated MLAA-34 stable HeLa cells were significantly higher than that of ATO-treated controls, and the apoptosis rate and proportion of G2/M cells also decreased. We found that ATO treatment of HeLa cells resulted in significant decreases in the expression of β-catenin mRNA and protein and the downstream target factors c-Myc, cyclin B1, and cyclin D1 in the Wnt signaling pathway. Notably, ATO-treated MLAA-34 stable HeLa cells showed a significant reduction in the ATO-mediated downregulation of these factors. In addition, MLAA-34 overexpression significantly increased the expression of nuclear β-catenin protein in ATO-treated cells compared with HeLa cells treated only with ATO. Thus, here we have found that the Wnt/β-catenin signaling pathway is involved in ATO-induced apoptosis in HeLa cells. MLAA-34 reduces ATO-induced apoptosis and G2/M arrest, and the anti-apoptotic effect may be achieved by activating the Wnt/β-catenin signaling pathway in HeLa cells. PMID:29059232

Pro-Inflammatory and Pro-Oxidant Status of Pancreatic Islet In Vitro Is Controlled by TLR-4 and HO-1 Pathways

PubMed Central

Vivot, Kevin; Langlois, Allan; Bietiger, William; Dal, Stéphanie; Seyfritz, Elodie; Pinget, Michel; Jeandidier, Nathalie; Maillard, Elisa; Gies, Jean-Pierre; Sigrist, Séverine

2014-01-01

Since their isolation until implantation, pancreatic islets suffer a major stress leading to the activation of inflammatory reactions. The maintenance of controlled inflammation is essential to preserve survival and function of the graft. Identification and targeting of pathway(s) implicated in post-transplant detrimental inflammatory events, is mandatory to improve islet transplantation success. We sought to characterize the expression of the pro-inflammatory and pro-oxidant mediators during islet culture with a focus on Heme oxygenase (HO-1) and Toll-like receptors-4 signaling pathways. Rat pancreatic islets were isolated and pro-inflammatory and pro-oxidant status were evaluated after 0, 12, 24 and 48 hours of culture through TLR-4, HO-1 and cyclooxygenase-2 (COX-2) expression, CCL-2 and IL-6 secretion, ROS (Reactive Oxygen Species) production (Dihydroethidine staining, DHE) and macrophages migration. To identify the therapeutic target, TLR4 inhibition (CLI-095) and HO-1 activation (cobalt protoporphyrin,CoPP) was performed. Activation of NFκB signaling pathway was also investigated. After isolation and during culture, pancreatic islet exhibited a proinflammatory and prooxidant status (increase levels of TLR-4, COX-2, CCL-2, IL-6, and ROS). Activation of HO-1 or inhibition of TLR-4 decreased inflammatory status and oxidative stress of islets. Moreover, the overexpression of HO-1 induced NFκB phosphorylation while the inhibition of TLR-4 had no effect NFκB activation. Finally, inhibition of pro-inflammatory pathway induced a reduction of macrophages migration. These data demonstrated that the TLR-4 signaling pathway is implicated in early inflammatory events leading to a pro-inflammatory and pro-oxidant status of islets in vitro. Moreover, these results provide the mechanism whereby the benefits of HO-1 target in TLR-4 signaling pathway. HO-1 could be then an interesting target to protect islets before transplantation. PMID:25343247

LRP5 and plasma cholesterol levels modulate the canonical Wnt pathway in peripheral blood leukocytes.

PubMed

Borrell-Pages, Maria; Carolina Romero, July; Badimon, Lina

2015-08-01

Inflammation is triggered after invasion or injury to restore homeostasis. Although the activation of Wnt/β-catenin signaling is one of the first molecular responses to cellular damage, its role in inflammation is still unclear. It was our hypothesis that the low-density lipoprotein (LDL) receptor-related protein 5 (LRP5) and the canonical Wnt signaling pathway are modulators of inflammatory mechanisms. Wild-type (WT) and LRP5(-/-) mice were fed a hypercholesterolemic (HC) diet to trigger dislipidemia and chronic inflammation. Diets were supplemented with plant sterol esters (PSEs) to induce LDL cholesterol lowering and the reduction of inflammation. HC WT mice showed increased serum cholesterol levels that correlated with increased Lrp5 and Wnt/β-catenin gene expression while in the HC LRP5(-/-) mice Wnt/β-catenin pathway was shut down. Functionally, HC induced pro-inflammatory gene expression in LRP5(-/-) mice, suggesting an inhibitory role of the Wnt pathway in inflammation. Dietary PSE administration downregulated serum cholesterol levels in WT and LRP5(-/-) mice. Furthermore, in WT mice PSE increased anti-inflammatory genes expression and inhibited Wnt/β-catenin activation. Hepatic gene expression of Vldlr, Lrp2 and Lrp6 was increased after HC feeding in WT mice but not in LRP5(-/-) mice, suggesting a role for these receptors in the clearance of plasmatic lipoproteins. Finally, an antiatherogenic role for LRP5 was demonstrated as HC LRP5(-/-) mice developed larger aortic atherosclerotic lesions than WT mice. Our results show an anti-inflammatory, pro-survival role for LRP5 and the Wnt signaling pathway in peripheral blood leukocytes.

Molecular and Biochemical Basis for Stress-Induced Accumulation of Free and Bound p-Coumaraldehyde in Cucumber1[W][OA

PubMed Central

Varbanova, Marina; Porter, Katie; Lu, Fachuang; Ralph, John; Hammerschmidt, Ray; Jones, A. Daniel; Day, Brad

2011-01-01

To elucidate the genetic and biochemical regulation of elicitor-induced p-coumaraldehyde accumulation in plants, we undertook a multifaceted approach to characterize the metabolic flux through the phenylpropanoid pathway via the characterization and chemical analysis of the metabolites in the p-coumaryl, coniferyl, and sinapyl alcohol branches of this pathway. Here, we report the identification and characterization of four cinnamyl alcohol dehydrogenases (CADs) from cucumber (Cucumis sativus) with low activity toward p-coumaraldehyde yet exhibiting significant activity toward other phenylpropanoid hydroxycinnamaldehydes. As part of this analysis, we identified and characterized the activity of a hydroxycinnamoyl-coenzyme A:shikimate hydroxycinnamoyl transferase (HCT) capable of utilizing shikimate and p-coumaroyl-coenzyme A to generate p-coumaroyl shikimate. Following pectinase treatment of cucumber, we observed the rapid accumulation of p-coumaraldehyde, likely the result of low aldehyde reductase activity (i.e. alcohol dehydrogenase in the reverse reaction) of CsCAD enzymes on p-coumaraldehyde. In parallel, we noted a concomitant reduction in the activity of CsHCT. Taken together, our findings support the hypothesis that the up-regulation of the phenylpropanoid pathway upon abiotic stress greatly enhances the overall p-coumaryl alcohol branch of the pathway. The data presented here point to a role for CsHCT (as well as, presumably, p-coumarate 3-hydroxylase) as a control point in the regulation of the coniferyl and sinapyl alcohol branches of this pathway. This mechanism represents a potentially evolutionarily conserved process to efficiently and quickly respond to biotic and abiotic stresses in cucurbit plants, resulting in the rapid lignification of affected tissues. PMID:21940999

Quercetin suppresses the chymotrypsin-like activity of proteasome via inhibition of MEK1/ERK1/2 signaling pathway in hepatocellular carcinoma HepG2 cells.

PubMed

Ding, Youming; Chen, Xiaoyan; Wang, Bin; Yu, Bin; Ge, Jianhui; Shi, Xiaokang

2018-05-01

The proteasomal system is a promising target for cancer treatment. Quercetin (Que), a flavonoid compound with antitumor ability, displays the inhibitory effect on proteasome activity. However, the underlying molecular mechanisms are ill defined. The present study found that Que treatment significantly reduced the chymotrypsin-like protease activity of proteasome whereas the trypsin- and caspase-like protease activities remained unchanged in HepG2 cancer cells, along with activation of p38 MAPK and JNK and reduction of ERK1/2 phosphorylation. Que-reduced proteasome activity could not be reverted by inhibition of p38 MAPK and JNK signaling pathway. In addition, MEK1 overexpression or knockdown upregulated or downregulated the chymotrypsin-like protease activity of proteasome, respectively. Both Que and MEK1/ERK1/2 inhibitor attenuated the expression levels of proteasome β subunits. These results indicate that Que-induced suppression of MEK1/ERK1/2 signaling and subsequent reduction of proteasome β subunits is responsible for its inhibitory impacts on proteasome activity.

In silico and in vitro studies of the reduction of unsaturated α,β bonds of trans-2-hexenedioic acid and 6-amino-trans-2-hexenoic acid – Important steps towards biobased production of adipic acid

PubMed Central

Westman, Gunnar; Eriksson, Leif A.; Mapelli, Valeria

2018-01-01

The biobased production of adipic acid, a precursor in the production of nylon, is of great interest in order to replace the current petrochemical production route. Glucose-rich lignocellulosic raw materials have high potential to replace the petrochemical raw material. A number of metabolic pathways have been proposed for the microbial conversion of glucose to adipic acid, but achieved yields and titers remain to be improved before industrial applications are feasible. One proposed pathway starts with lysine, an essential metabolite industrially produced from glucose by microorganisms. However, the drawback of this pathway is that several reactions are involved where there is no known efficient enzyme. By changing the order of the enzymatic reactions, we were able to identify an alternative pathway with one unknown enzyme less compared to the original pathway. One of the reactions lacking known enzymes is the reduction of the unsaturated α,β bond of 6-amino-trans-2-hexenoic acid and trans-2-hexenedioic acid. To identify the necessary enzymes, we selected N-ethylmaleimide reductase from Escherichia coli and Old Yellow Enzyme 1 from Saccharomyces pastorianus. Despite successful in silico docking studies, where both target substrates could fit in the enzyme pockets, and hydrogen bonds with catalytic residues of both enzymes were predicted, no in vitro activity was observed. We hypothesize that the lack of activity is due to a difference in electron withdrawing potential between the naturally reduced aldehyde and the carboxylate groups of our target substrates. Suggestions for protein engineering to induce the reactions are discussed, as well as the advantages and disadvantages of the two metabolic pathways from lysine. We have highlighted bottlenecks associated with the lysine pathways, and proposed ways of addressing them. PMID:29474495

Myeloperoxidase amplified high glucose-induced endothelial dysfunction in vasculature: Role of NADPH oxidase and hypochlorous acid.

PubMed

Tian, Rong; Ding, Yun; Peng, Yi-Yuan; Lu, Naihao

2017-03-11

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived reactive oxygen species (ROS) such as superoxide and hydrogen peroxide (H 2 O 2 ), have emerged as important molecules in the pathogenesis of diabetic endothelial dysfunction. Additionally, neutrophils-derived myeloperoxidase (MPO) and MPO-catalyzed hypochlorous acid (HOCl) play important roles in the vascular injury. However, it is unknown whether MPO can use vascular-derived ROS to induce diabetic endothelial dysfunction. In the present study, we demonstrated that NADPH oxidase was the main source of ROS formation in high glucose-cultured human umbilical vein endothelial cells (HUVECs), and played a critical role in high glucose-induced endothelial dysfunction such as cell apoptosis, loss of cell viability and reduction of nitric oxide (NO). However, the addition of MPO could amplify the high glucose-induced endothelial dysfunction which was inhibited by the presence of apocynin (NADPH oxidase inhibitor), catalase (H 2 O 2 scavenger), or methionine (HOCl scavenger), demonstrating the contribution of NADPH oxidase-H 2 O 2 -MPO-HOCl pathway in the MPO/high glucose-induced vascular injury. In high glucose-incubated rat aortas, MPO also exacerbated the NADPH oxidase-induced impairment of endothelium-dependent relaxation. Consistent with these in vitro data, in diabetic rat aortas, both MPO expresion and NADPH oxidase activity were increased while the endothelial function was simultaneously impaired. The results suggested that vascular-bound MPO could amplify high glucose-induced vascular injury in diabetes. MPO-NADPH oxidase-HOCl may represent an important pathogenic pathway in diabetic vascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Hepatoprotective properties of kombucha tea against TBHP-induced oxidative stress via suppression of mitochondria dependent apoptosis.

PubMed

Bhattacharya, Semantee; Gachhui, Ratan; Sil, Parames C

2011-06-01

Kombucha, a fermented tea (KT) is claimed to possess many beneficial properties. Recent studies have suggested that KT prevents paracetamol and carbon tetrachloride-induced hepatotoxicity. We investigated the beneficial role of KT was against tertiary butyl hydroperoxide (TBHP) induced cytotoxicity and cell death in murine hepatocytes. TBHP is a well known reactive oxygen species (ROS) inducer, and it induces oxidative stress in organ pathophysiology. In our experiments, TBHP caused a reduction in cell viability, enhanced the membrane leakage and disturbed the intra-cellular antioxidant machineries while simultaneous treatment of the cells with KT and this ROS inducer maintained membrane integrity and prevented the alterations in the cellular antioxidant status. These findings led us to explore the detailed molecular mechanisms involved in the protective effect of KT. TBHP introduced apoptosis as the primary phenomena of cell death as evidenced by flow cytometric analyses. In addition, ROS generation, changes in the mitochondrial membrane potential, cytochrome c release, activation of caspases (3 and 9) and Apaf-1 were detected confirming involvement of mitochondrial pathway in this pathophysiology. Simultaneous treatment of KT with TBHP, on the other hand, protected the cells against oxidative injury and maintained their normal physiology. In conclusion, KT was found to modulate the oxidative stress induced apoptosis in murine hepatocytes probably due to its antioxidant activity and functioning via mitochondria dependent pathways and could be beneficial against liver diseases, where oxidative stress is known to play a crucial role. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Binge ethanol exposure increases the Krüppel-like factor 11-monoamine oxidase (MAO) pathway in rats: Examining the use of MAO inhibitors to prevent ethanol-induced brain injury

PubMed Central

Duncan, Jeremy W.; Zhang, Xiao; Wang, Niping; Johnson, Shakevia; Harris, Sharonda; Udemgba, Chinelo; Ou, Xiao-Ming; Youdim, Moussa B.; Stockmeier, Craig A.; Wang, Jun Ming

2016-01-01

Binge drinking induces several neurotoxic consequences including oxidative stress and neurodegeneration. Because of these effects, drugs which prevent ethanol-induced damage to the brain may be clinically beneficial. In this study, we investigated the ethanol-mediated KLF11-MAO cell death cascade in the frontal cortex of Sprague–Dawley rats exposed to a modified Majchowicz 4-day binge ethanol model and control rats. Moreover, MAO inhibitors (MAOIs) were investigated for neuroprotective activity against binge ethanol. Binge ethanol-treated rats demonstrated a significant increase in KLF11, both MAO isoforms, protein oxidation and caspase-3, as well as a reduction in BDNF expression in the frontal cortex compared to control rats. MAOIs prevented these binge ethanol-induced changes, suggesting a neuroprotective benefit. Neither binge ethanol nor MAOI treatment significantly affected protein expression levels of the oxidative stress enzymes, SOD2 or catalase. Furthermore, ethanol-induced antinociception was enhanced following exposure to the 4-day ethanol binge. These results demonstrate that the KLF11-MAO pathway is activated by binge ethanol exposure and MAOIs are neuroprotective by preventing the binge ethanol-induced changes associated with this cell death cascade. This study supports KLF11-MAO as a mechanism of ethanol-induced neurotoxicity and cell death that could be targeted with MAOI drug therapy to alleviate alcohol-related brain injury. Further examination of MAOIs to reduce alcohol use disorder-related brain injury could provide pivotal insight to future pharmacotherapeutic opportunities. PMID:26805422

Vitamin C deficiency aggravates tumor necrosis factor α-induced insulin resistance.

PubMed

Qing, Zhou; Xiao-Hui, Wu; Xi-Mei, Wu; Chao-Chun, Zou

2018-06-15

Chronic low-grade inflammation plays a major role in the development of insulin resistance. The potential role and underlying mechanism of vitamin C, an antioxidant and anti-inflammatory agent, was investigated in tumor necrosis factor-α (TNF-α)-induced insulin resistance. Gulonolactone oxidase knockout (Gulo -/- ) mice genetically unable to synthesize vitamin C were used to induce insulin resistance by continuously pumping small doses of TNF-α for seven days, and human liver hepatocellular carcinoma cells (HepG2 cells) were used to induce insulin resistance by treatment with TNF-α. Vitamin C deficiency aggravated TNF-α-induced insulin resistance in Gulo -/- mice, resulting in worse glucose tolerance test (GTT) results, higher fasting plasma insulin level, and the inactivation of the protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β) pathway in the liver. Vitamin C deficiency also worsened liver lipid accumulation and inflammation in TNF-α-treated Gulo -/- mice. In HepG2 cells, vitamin C reversed the TNF-α-induced reduction of glucose uptake and glycogen synthesis, which were mediated by increasing GLUT2 levels and the activation of the insulin receptor substrate (IRS-1)/AKT/GSK3β pathway. Furthermore, vitamin C inhibited the TNF-α-induced activation of not only the mitogen-activated protein kinase (MAPKs), but also nuclear factor-kappa B (NF-κB) signaling. Taken together, vitamin C is essential for preventing and improving insulin resistance, and the supplementing with vitamin C may be an effective therapeutic intervention for metabolic disorders. Copyright © 2018 Elsevier B.V. All rights reserved.

Sulforaphane reduction of testicular apoptotic cell death in diabetic mice is associated with the upregulation of Nrf2 expression and function.

PubMed

Wang, Yonggang; Zhang, Zhiguo; Guo, Weiying; Sun, Weixia; Miao, Xiao; Wu, Hao; Cong, Xianling; Wintergerst, Kupper A; Kong, Xiangbo; Cai, Lu

2014-07-01

Diabetes-induced testicular cell death is due predominantly to oxidative stress. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important transcription factor in controlling the antioxidative system and is inducible by sulforaphane (SFN). To test whether SFN prevents diabetes-induced testicular cell death, an insulin-defective stage of type 2 diabetes (IDS-T2DM) was induced in mice. This was accomplished by feeding them a high-fat diet (HFD) for 3 mo to induce insulin resistance and then giving one intraperitoneal injection of streptozotocin to induce hyperglycemia while age-matched control mice were fed a normal diet (ND). IDS-T2DM and ND-fed control mice were then further subdivided into those with or without 4-mo SFN treatment. IDS-T2DM induced significant increases in testicular cell death presumably through receptor and mitochondrial pathways, shown by increased ratio of Bax/Bcl2 expression and cleavage of caspase-3 and caspase-8 without significant change of endoplasmic reticulum stress. Diabetes also significantly increased testicular oxidative damage and inflammation. All of these diabetic effects were significantly prevented by SFN treatment with upregulated Nrf2 expression. These results suggest that IDS-T2DM induces testicular cell death presumably through caspase-8 activation and mitochondria-mediated cell death pathways and also by significantly downregulating testicular Nrf2 expression and function. SFN upregulates testicular Nrf2 expression and its target antioxidant expression, which was associated with significant protection of the testis from IDS-T2DM-induced germ cell death. Copyright © 2014 the American Physiological Society.

Protective effect of coconut water concentrate and its active component shikimic acid against hydroperoxide mediated oxidative stress through suppression of NF-κB and activation of Nrf2 pathway.

PubMed

Manna, Krishnendu; Khan, Amitava; Kr Das, Dipesh; Bandhu Kesh, Swaraj; Das, Ujjal; Ghosh, Sayan; Sharma Dey, Rakhi; Das Saha, Krishna; Chakraborty, Anindita; Chattopadhyay, Sreya; Dey, Sanjit; Chattopadhyay, Debprasad

2014-08-08

Conventionally coconut water has been used as an 'excellent hydrating' drink that maintain the electrolyte balance and help in treating diverse ailments related to oxidative stress including liver function. The present study was aimed to elucidate whether and how the coconut water concentrate (CWC) and its major active phytoconstituent shikimic acid (SA) can effectively protect murine hepatocytes from the deleterious effect of hydroperoxide-mediated oxidative stress. Bioactivity guided fractionation of CWC resulted in the isolation of a couple of known compounds. Freshly isolated murine hepatocytes were exposed to hydrogen peroxide (H2O2) (1 and 3mM) in the presence or absence of CWC (200 and 400 μg/ml) and SA (40 μM) for the determination of antioxidative, DNA protective, cellular ROS level by modern methods, including immunoblot and flowcytometry to find out the possible mechanism of action. Pre-treatment of hepatocyte with CWC and SA showed significant prevention of H2O2-induced intracellular ROS generation, nuclear DNA damage along with the formation of hepatic TBARS and cellular nitrite. Further, the H2O2 induced cell death was arrested in the presence of CWC through the inhibition of CDC42 mediated SAPK/JNK pathways and activation of other molecules of apoptotic pathways, including Bax and caspase3. Moreover, CWC and SA help in maintaining the GSH level and endogenous antioxidants like Mn-SOD, to support intracellular defense mechanisms, probably through the transcriptional activation of Nrf2; and inhibition of nuclear translocation of NF-κB. CWC and its active components SA reversed the H2O2 induced oxidative damage in hepatocytes, probably through the inhibition of NF-κB, with the activation of PI3K/Akt/Nrf2 pathway and reduction of apoptosis by interfering the SAPK/JNK/Bax pathway. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Corn silk maysin induces apoptotic cell death in PC-3 prostate cancer cells via mitochondria-dependent pathway.

PubMed

Lee, Jisun; Lee, Seul; Kim, Sun-Lim; Choi, Ji Won; Seo, Jeong Yeon; Choi, Doo Jin; Park, Yong Il

2014-12-05

Despite recent advances in prostate cancer diagnostics and therapeutics, the overall survival rate still remains low. This study was aimed to assess potential anti-cancer activity of maysin, a major flavonoid of corn silk (CS, Zea mays L.), in androgen-independent human prostate cancer cells (PC-3). Maysin was isolated from CS of Kwangpyeongok, a Korean hybrid corn, via methanol extraction and preparative C18 reverse phase column chromatography. Maysin cytotoxicity was determined by either monitoring cell viability in various cancer cell lines by MTT assay or morphological changes. Apoptotic cell death was assessed by annexin V-FITC/PI double staining, depolarization of mitochondrial membrane potential (MMP), expression levels of Bcl-2 and pro-caspase-3 and by terminal transferase mediated dUTP-fluorescein nick end labeling (TUNEL) staining. Underlying mechanism in maysin-induced apoptosis of PC-3 cells was explored by evaluating its effects on Akt and ERK pathway. Maysin dose-dependently reduced the PC-3 cell viability, with an 87% reduction at 200 μg/ml. Maysin treatment significantly induced apoptotic cell death, DNA fragmentation, depolarization of MMP, and reduction in Bcl-2 and pro-caspase-3 expression levels. Maysin also significantly attenuated phosphorylation of Akt and ERK. A combined treatment with maysin and other known anti-cancer agents, including 5-FU, etoposide, cisplatin, or camptothecin, synergistically enhanced PC-3 cell death. These results suggested for the first time that maysin inhibits the PC-3 cancer cell growth via stimulation of mitochondria-dependent apoptotic cell death and may have a strong therapeutic potential for the treatment of either chemo-resistant or androgen-independent human prostate cancer. Copyright © 2014 Elsevier Inc. All rights reserved.

Histamine H4-Receptors Inhibit Mast Cell Renin Release in Ischemia/Reperfusion via Protein Kinase Cε-Dependent Aldehyde Dehydrogenase Type-2 Activation

PubMed Central

Aldi, Silvia; Takano, Ken-ichi; Tomita, Kengo; Koda, Kenichiro; Chan, Noel Y.-K.; Marino, Alice; Salazar-Rodriguez, Mariselis; Thurmond, Robin L.

2014-01-01

Renin released by ischemia/reperfusion (I/R) from cardiac mast cells (MCs) activates a local renin-angiotensin system (RAS) causing arrhythmic dysfunction. Ischemic preconditioning (IPC) inhibits MC renin release and consequent activation of this local RAS. We postulated that MC histamine H4-receptors (H4Rs), being Gαi/o-coupled, might activate a protein kinase C isotype–ε (PKCε)–aldehyde dehydrogenase type-2 (ALDH2) cascade, ultimately eliminating MC-degranulating and renin-releasing effects of aldehydes formed in I/R and associated arrhythmias. We tested this hypothesis in ex vivo hearts, human mastocytoma cells, and bone marrow–derived MCs from wild-type and H4R knockout mice. We found that activation of MC H4Rs mimics the cardioprotective anti-RAS effects of IPC and that protection depends on the sequential activation of PKCε and ALDH2 in MCs, reducing aldehyde-induced MC degranulation and renin release and alleviating reperfusion arrhythmias. These cardioprotective effects are mimicked by selective H4R agonists and disappear when H4Rs are pharmacologically blocked or genetically deleted. Our results uncover a novel cardioprotective pathway in I/R, whereby activation of H4Rs on the MC membrane, possibly by MC-derived histamine, leads sequentially to PKCε and ALDH2 activation, reduction of toxic aldehyde-induced MC renin release, prevention of RAS activation, reduction of norepinephrine release, and ultimately to alleviation of reperfusion arrhythmias. This newly discovered protective pathway suggests that MC H4Rs may represent a new pharmacologic and therapeutic target for the direct alleviation of RAS-induced cardiac dysfunctions, including ischemic heart disease and congestive heart failure. PMID:24696042

Nitrate-induced photodegradation of atenolol in aqueous solution: kinetics, toxicity and degradation pathways.

PubMed

Ji, Yuefei; Zeng, Chao; Ferronato, Corinne; Chovelon, Jean-Marc; Yang, Xi

2012-07-01

The extensive utilization of β-blockers worldwide led to frequent detection in natural water. In this study the photolysis behavior of atenolol (ATL) and toxicity of its photodegradation products were investigated in the presence of nitrate ions. The results showed that ATL photodegradation followed pseudo-first-order kinetics upon simulated solar irradiation. The photodegradation was found to be dependent on nitrate concentration and increasing the nitrate from 0.5 mML(-1) to 10 mML(-1) led to the enhancement of rate constant from 0.00101 min(-1) to 0.00716 min(-1). Hydroxyl radical was determined to play a key role in the photolysis process by using isopropanol as molecular probe. Increasing the solution pH from 4.8 to 10.4, the photodegradation rate slightly decreased from 0.00246 min(-1) to 0.00195 min(-1), probably due to pH-dependent effect of nitrate-induced .OH formation. Bicarbonate decreased the photodegradation of ATL in the presence of nitrate ions mainly through pH effect, while humic substance inhibited the photodegradation via both attenuating light and competing radicals. Upon irradiation for 240 min, only 10% reduction of total organic carbon (TOC) can be achieved in spite of 72% transformation rate of ATL, implying a majority of ATL transformed into intermediate products rather than complete mineralization. The main photoproducts of ATL were identified by using solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) techniques and possible nitrate-induced photodegradation pathways were proposed. The toxicity of the phototransformation products was evaluated using aquatic species Daphnia magna, and the results revealed that photodegradation was an effective mechanism for ATL toxicity reduction in natural waters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Silicon-Induced Changes in Antifungal Phenolic Acids, Flavonoids, and Key Phenylpropanoid Pathway Genes during the Interaction between Miniature Roses and the Biotrophic Pathogen Podosphaera pannosa1[W

PubMed Central

Shetty, Radhakrishna; Fretté, Xavier; Jensen, Birgit; Shetty, Nandini Prasad; Jensen, Jens Due; Jørgensen, Hans Jørgen Lyngs; Newman, Mari-Anne; Christensen, Lars Porskjær

2011-01-01

Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection. PMID:22021421

Muscle wasting in osteoarthritis model induced by anterior cruciate ligament transection.

PubMed

Silva, Jordana Miranda de Souza; Alabarse, Paulo Vinicius Gil; Teixeira, Vivian de Oliveira Nunes; Freitas, Eduarda Correa; de Oliveira, Francine Hehn; Chakr, Rafael Mendonça da Silva; Xavier, Ricardo Machado

2018-01-01

This study aimed to investigate the molecular pathways involved in muscle wasting in an animal model of osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT) in rats. Reduction of protein syntheses, increased proteolysis and impaired muscle regeneration are important pathways related to muscle wasting, and myogenin, MyoD, myostatin and MuRF-1 are some of their markers. Female Wistar rats were allocated into two groups: OA (submitted to the ACLT) and SHAM (submitted to surgery without ACLT). Nociception, spontaneous exploratory locomotion and body weight of animals were evaluated weekly. Twelve weeks after the disease induction, animals were euthanized, and the right knee joints were collected. Gastrocnemius muscle of the right hind paw were dissected and weighed. Gastrocnemius was used for evaluation of muscle atrophy and expression of IL-1β, TNF-α, Pax7, myogenin, MyoD, myostatin and MuRF-1. Histopathology of the knee confirmed the development of the disease in animals of OA group. Gastrocnemius of OA animals showed a reduction of about 10% in area and an increased IL-1β expression compared to animals of SHAM group. Expression of myostatin was increased in OA group, while myogenin expression was decreased. TNF-α, Pax7, MuRF-1 and MyoD expression was similar in both OA and SHAM groups. Nociception was significantly elevated in OA animals in the last two weeks of experimental period. Spontaneous exploratory locomotion, body weight and weight of gastrocnemius showed no difference between OA and SHAM groups. Gastrocnemius atrophy in OA induced by ACLT involves elevated expression of IL-1β within the muscle, as well as increased expression of myostatin and decreased expression of myogenin. Therefore, muscle wasting may be linked to impaired muscle regeneration.

Inferior vena cava filters in pulmonary embolism: A historic controversy.

PubMed

Jerjes-Sanchez, Carlos; Rodriguez, David; Navarrete, Aline; Parra-Cantu, Carolina; Joya-Harrison, Jorge; Vazquez, Eduardo; Ramirez-Rivera, Alicia

Rationale for non-routine use of inferior venous cava filters (IVCF) in pulmonary embolism (PE) patients. Thrombosis mechanisms involved with IVCF placement and removal, the blood-contacting medical device inducing clotting, and the inorganic polyphosphate in the contact activation pathway were analyzed. In addition, we analyzed clinical evidence from randomized trials, including patients with and without cancer. Furthermore, we estimated the absolute risk reduction (ARR), the relative risk reduction (RRR), and the number needed to treat (NNT) based on the results of each study using a frequency table. Finally, we analyzed the outcome of our PE patients that were submitted to thrombolysis with short and long term follow-up. IVCF induces thrombosis by several mechanisms including placement and removal, rapid protein adsorption, and simultaneous surface-induced activation via the contact activation pathway. Also, inorganic polyphosphate has an important role as a procoagulant, reversing the effect of anticoagulants. Randomized control trials included 904 cancer and non-cancer PE patients. In terms of ARR, RRR, and NNT, there is no evidence for routine use of IVCF. In 290 patients with proved PE, extensive thrombotic burden and right ventricular dysfunction under thrombolysis and oral anticoagulation, we observed a favorable outcome in a short- and long-term follow-up; additionally, IVCF was only used in 5% of these patients. Considering the complex mechanisms of thrombosis related with IVCF, the evidence from randomized control trials and ARR, RRR, and NNT obtained from venous thromboembolism patients with and without cancer, non-routine use of IVCF is recommended. Copyright © 2017 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes

PubMed Central

Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

2017-01-01

Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium-infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite. PMID:28220125

HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes.

PubMed

Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

2017-01-01

Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium -infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite.

Cisplatin triggers atrophy of skeletal C2C12 myotubes via impairment of Akt signalling pathway and subsequent increment activity of proteasome and autophagy systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanzani, Alessandro, E-mail: fanzani@med.unibs.it; Zanola, Alessandra; Rovetta, Francesca

2011-02-01

Cisplatin (cisPt) is an antineoplastic drug which causes an array of adverse effects on different organs and tissues, including skeletal muscle. In this work we show that cisPt behaves as a potent trigger to activate protein hypercatabolism in skeletal C2C12 myotubes. Within 24 h of 50 {mu}M cisPt administration, C2C12 myotubes displayed unchanged cell viability but showed a subset of hallmark signs typically recognized during atrophy, including severe reduction in body size, repression of Akt phosphorylation, transcriptional up-regulation of atrophy-related genes, such as atrogin-1, gabarap, beclin-1 and bnip-3, and loss of myogenic markers. As a consequence, proteasomal activity and formationmore » of autophagosomes were remarkably increased in cisPt-treated myotubes, but forced stimulation of Akt pathway, as obtained through insulin administration or delivery of a constitutively activated Akt form, was sufficient to counter the cisPt-induced protein breakdown, leading to rescue of atrophic size. Overall, these results indicate that cisPt induces atrophy of C2C12 myotubes via activation of proteasome and autophagy systems, suggesting that the Akt pathway represents one sensitive target of cisPt molecular action in skeletal muscle.« less

Redox potential as a master variable controlling pathways of metal reduction by Geobacter sulfurreducens

PubMed Central

Levar, Caleb E; Hoffman, Colleen L; Dunshee, Aubrey J; Toner, Brandy M; Bond, Daniel R

2017-01-01

Geobacter sulfurreducens uses at least two different pathways to transport electrons out of the inner membrane quinone pool before reducing acceptors beyond the outer membrane. When growing on electrodes poised at oxidizing potentials, the CbcL-dependent pathway operates at or below redox potentials of –0.10 V vs the standard hydrogen electrode, whereas the ImcH-dependent pathway operates only above this value. Here, we provide evidence that G. sulfurreducens also requires different electron transfer proteins for reduction of a wide range of Fe(III)- and Mn(IV)-(oxyhydr)oxides, and must transition from a high- to low-potential pathway during reduction of commonly studied soluble and insoluble metal electron acceptors. Freshly precipitated Fe(III)-(oxyhydr)oxides could not be reduced by mutants lacking the high-potential pathway. Aging these minerals by autoclaving did not change their powder X-ray diffraction pattern, but restored reduction by mutants lacking the high-potential pathway. Mutants lacking the low-potential, CbcL-dependent pathway had higher growth yields with both soluble and insoluble Fe(III). Together, these data suggest that the ImcH-dependent pathway exists to harvest additional energy when conditions permit, and CbcL switches on to allow respiration closer to thermodynamic equilibrium conditions. With evidence of multiple pathways within a single organism, the study of extracellular respiration should consider not only the crystal structure or solubility of a mineral electron acceptor, but rather the redox potential, as this variable determines the energetic reward affecting reduction rates, extents, and final microbial growth yields in the environment. PMID:28045456

Leachate pre-treatment strategies before recirculation in landfill bioreactors.

PubMed

Vigneron, V; Bouchez, T; Bureau, C; Mailly, N; Mazeas, L; Duquennoi, C; Audic, J M; Hébé, L; Bernet, N

2005-01-01

Nitrified leachate recirculation represents a promising strategy for a more sustainable landfill management. Our objective was to determine the reactions involved in nitrate reduction in municipal solid waste batch biodegradation tests. Anaerobic digestion of waste in the three control reactors showed a good reproducibility. In two test reactors, nitrate was added at various moments of the waste degradation process. We observed that: (1) H2S concentration controlled the nitrate reduction pathway: above a certain threshold of H2S, dissimilatory nitrate reduction to ammonium (DNRA) replaced denitrification. (2) N2O/N2 ratio varied with the organic carbon concentration: the lower the easily biodegradable carbon concentration, the higher the N2O/N2 ratio. (3) N2 was consumed after denitrification. The possibility of a nitrogen fixation reaction in the presence of NH4 is discussed. Nitrified leachate recirculation during acidogenesis should be avoided because of higher H2S production which could induce DNRA.

TGF-beta and HGF transmit the signals through JNK-dependent Smad2/3 phosphorylation at the linker regions.

PubMed

Mori, Shigeo; Matsuzaki, Koichi; Yoshida, Katsunori; Furukawa, Fukiko; Tahashi, Yoshiya; Yamagata, Hideo; Sekimoto, Go; Seki, Toshihito; Matsui, Hirofumi; Nishizawa, Mikio; Fujisawa, Jun-ichi; Okazaki, Kazuichi

2004-09-23

Although hepatocyte growth factor (HGF) can act synergistically or antagonistically with transforming growth factor-beta (TGF-beta) signaling, molecular mechanism of their crosstalk remains unknown. Using antibodies which selectively distinguished receptor-regulated Smads (R-Smads) phosphorylated at linker regions from those at C-terminal regions, we herein showed that either HGF or TGF-beta treatment of normal stomach-origin cells activated the JNK pathway, thereafter inducing endogenous R-Smads phosphorylation at linker regions. However, the phosphorylation at their C-terminal regions was not induced by HGF treatment. The activated JNK could directly phosphorylate R-Smads in vitro at the same sites that were phosphorylated in response to TGF-beta or HGF in vivo. Thus, the linker regions of R-Smads were the common phosphorylation sites for HGF and TGF-beta signaling pathways. The phosphorylation induced by simultaneous treatment with HGF and TGF-beta allowed R-Smads to associate with Smad4 and to translocate into the nucleus. JNK pathway involved HGF and TGF-beta-mediated infiltration potency since a JNK inhibitor SP600125 caused the reduction of invasive capacity induced by HGF and TGF-beta signals. Moreover, a combined treatment with HGF and TGF-beta led to a potent increase in plasminogen activator inhibitor type 1 transcriptional activity through Smad3 phosphorylation at the linker region. In contrast, HGF treatment reduced TGF-beta-dependent activation of p15INK4B promoter, in which Smad3 phosphorylation at the C-terminal region was involved. In conclusion, HGF and TGF-beta transmit the signals through JNK-mediated R-Smads phosphorylation at linker regions.

Hypertrophy Stimulation at the Onset of Type I Diabetes Maintains the Soleus but Not the EDL Muscle Mass in Wistar Rats

PubMed Central

Fortes, Marco A. S.; Scervino, Maria V. M.; Marzuca-Nassr, Gabriel N.; Vitzel, Kaio F.; da Justa Pinheiro, Carlos H.; Curi, Rui

2017-01-01

Diabetes mellitus induces a reduction in skeletal muscle mass and strength. Strength training is prescribed as part of treatment since it improves glycemic control and promotes increase of skeletal muscle mass. The mechanisms involved in overload-induced muscle hypertrophy elicited at the establishment of the type I diabetic state was investigated in Wistar rats. The purpose was to examine whether the overload-induced hypertrophy can counteract the hypotrophy associated to the diabetic state. The experiments were performed in oxidative (soleus) or glycolytic (EDL) muscles. PI3K/Akt/mTOR protein synthesis pathway was evaluated 7 days after overload-induced hypertrophy of soleus and of EDL muscles. The mRNA expression of genes associated with different signaling pathways that control muscle hypertrophy was also evaluated: mechanotransduction (FAK), Wnt/β-catenin, myostatin, and follistatin. The soleus and EDL muscles when submitted to overload had similar hypertrophic responses in control and diabetic animals. The increase of absolute and specific twitch and tetanic forces had the same magnitude as muscle hypertrophic response. Hypertrophy of the EDL muscle from diabetic animals mostly involved mechanical loading-stimulated PI3K/Akt/mTOR pathway besides the reduced activation of AMP-activated protein kinase (AMPK) and decrease of myostatin expression. Hypertrophy was more pronounced in the soleus muscle of diabetic animals due to a more potent activation of rpS6 and increased mRNA expression of insulin-like growth factor-1 (IGF-1), mechano-growth factor (MGF) and follistatin, and decrease of myostatin, MuRF-1 and atrogin-1 contents. The signaling changes enabled the soleus muscle mass and force of the diabetic rats to reach the values of the control group. PMID:29123487

Hydrogen Sulfide Suppresses Oxidized Low-density Lipoprotein (Ox-LDL)-stimulated Monocyte Chemoattractant Protein 1 generation from Macrophages via the Nuclear Factor κB (NF-κB) Pathway*

PubMed Central

Du, Junbao; Huang, Yaqian; Yan, Hui; Zhang, Qiaoli; Zhao, Manman; Zhu, Mingzhu; Liu, Jia; Chen, Stella X.; Bu, Dingfang; Tang, Chaoshu; Jin, Hongfang

2014-01-01

This study was designed to examine the role of hydrogen sulfide (H2S) in the generation of oxidized low-density lipoprotein (ox-LDL)-stimulated monocyte chemoattractant protein 1 (MCP-1) from macrophages and possible mechanisms. THP-1 cells and RAW macrophages were pretreated with sodium hydrosulfide (NaHS) and hexyl acrylate and then treated with ox-LDL. The results showed that ox-LDL treatment down-regulated the H2S/cystathionine-β-synthase pathway, with increased MCP-1 protein and mRNA expression in both THP-1 cells and RAW macrophages. Hexyl acrylate promoted ox-LDL-induced inflammation, whereas the H2S donor NaHS inhibited it. NaHS markedly suppressed NF-κB p65 phosphorylation, nuclear translocation, DNA binding activity, and recruitment to the MCP-1 promoter in ox-LDL-treated macrophages. Furthermore, NaHS decreased the ratio of free thiol groups in p65, whereas the thiol reductant DTT reversed the inhibiting effect of H2S on the p65 DNA binding activity. Most importantly, site-specific mutation of cysteine 38 to serine in p65 abolished the effect of H2S on the sulfhydration of NF-κB and ox-LDL-induced NF-κB activation. These results suggested that endogenous H2S inhibited ox-LDL-induced macrophage inflammation by suppressing NF-κB p65 phosphorylation, nuclear translocation, DNA binding activity, and recruitment to the MCP-1 promoter. The sulfhydration of free thiol group on cysteine 38 in p65 served as a molecular mechanism by which H2S inhibited NF-κB pathway activation in ox-LDL-induced macrophage inflammation. PMID:24550391

Carnosic acid prevents COL1A2 transcription through the reduction of Smad3 acetylation via the AMPKα1/SIRT1 pathway.

PubMed

Zhao, Yan; Shi, Xue; Ding, Chunchun; Feng, Dongcheng; Li, Yang; Hu, Yan; Wang, Li; Gao, Dongyan; Tian, Xiaofeng; Yao, Jihong

2018-01-15

Carnosic acid (CA), a major bioactive component in rosemary extract, has many biological and pharmaceutical activities. Smad3 acetylation can regulate the transcription of type I α2 collagen (COL1A2), which is the major component of the extracellular matrix (ECM). The aim of the current study was to evaluate whether CA inhibits COL1A2 transcription via the reduction of Smad3 acetylation against liver fibrosis. The results showed that CA treatment significantly suppressed COL1A2 transcription and markedly decreased the deposition of ECM induced by dimethylamine (DMN) in rats. Importantly, the suppression of COL1A2 transcription following CA treatment depended on the reduction of Smad3 acetylation via the activation of Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide + (NAD + )-dependent deacetylase. SIRT1 siRNA increased the acetylation of Smad3 and blocked CA-down-regulated Smad3 deacetylation. Notably, CA-mediated AMP-activated protein kinase-α1 (AMPKα1) activation not only increased AMPKα1 phosphorylation but also increased SIRT1 expression, thus leading to a significant reduction in Smad3 acetylation. Furthermore, CA-mediated SIRT1 activation was inhibited by AMPKα1 siRNA. Collectively, CA can inhibit the transcription of COL1A2 through SIRT1-mediated Smad3 deacetylation, and the activation of SIRT1 by CA involves the AMPKα1/SIRT1 pathway in liver fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Electrochemistry suggests proton access from the exit site to the binuclear center in Paracoccus denitrificans cytochrome c oxidase pathway variants.

PubMed

Meyer, Thomas; Melin, Frédéric; Richter, Oliver-M H; Ludwig, Bernd; Kannt, Aimo; Müller, Hanne; Michel, Hartmut; Hellwig, Petra

2015-02-27

Two different pathways through which protons access cytochrome c oxidase operate during oxygen reduction from the mitochondrial matrix, or the bacterial cytoplasm. Here, we use electrocatalytic current measurements to follow oxygen reduction coupled to proton uptake in cytochrome c oxidase isolated from Paracoccus denitrificans. Wild type enzyme and site-specific variants with defects in both proton uptake pathways (K354M, D124N and K354M/D124N) were immobilized on gold nanoparticles, and oxygen reduction was probed electrochemically in the presence of varying concentrations of Zn(2+) ions, which are known to inhibit both the entry and the exit proton pathways in the enzyme. Our data suggest that under these conditions substrate protons gain access to the oxygen reduction site via the exit pathway. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Contrasting acute graft-versus-host disease effects of Tim-3/galectin-9 pathway blockade dependent upon the presence of donor regulatory T cells

PubMed Central

Veenstra, Rachelle G.; Taylor, Patricia A.; Zhou, Qing; Panoskaltsis-Mortari, Angela; Hirashima, Mitsuomi; Flynn, Ryan; Liu, Derek; Anderson, Ana C.; Strom, Terry B.; Kuchroo, Vijay K.

2012-01-01

T-cell immunoglobulin mucin-3 (Tim-3) is expressed on pathogenic T cells, and its ligand galectin-9 (gal-9) is up-regulated in inflamed tissues. When Tim-3+ T cells encounter high gal-9 levels, they are deleted. Tim-3 is up-regulated on activated T cells during GVHD. Inhibition of Tim-3/gal-9 binding by infusion of a Tim-3-Ig fusion protein or Tim-3−/− donor T cells increased T-cell proliferation and GVHD lethality. When the Tim-3/gal-9 pathway engagement was augmented using gal-9 transgenic recipients, GVHD lethality was slowed. Together, these data indicate a potential for modulating this pathway to reduce disease by increasing Tim-3 or gal-9 engagement. Paradoxically, when Tim-3/gal-9 was inhibited in the absence of donor T-regulatory cells (Tregs), GVHD was inhibited. GVHD reduction was associated with decreased colonic inflammatory cytokines as well as epithelial barrier destruction. CD25-depleted Tim-3−/− donor T cells underwent increased activation-induced cell death because of increased IFN-γ production. To our knowledge, these studies are the first to show that although the absence of Tim-3/gal-9 pathway interactions augments systemic GVHD, concurrent donor Treg depletion paradoxically and surprisingly inhibits GVHD. Thus, although donor Tregs typically inhibit GVHD, under some conditions, such Tregs actually may contribute to GVHD by reducing activation-induced T-cell death. PMID:22677125

TRPC3- and ETB receptor-mediated PI3K/AKT activation induces vasogenic edema formation following status epilepticus.

PubMed

Kim, Ji-Eun; Kang, Tae-Cheon

2017-10-01

Status epilepticus (SE, a prolonged seizure activity) is a high risk factor of developing vasogenic edema, which leads to secondary complications following SE. In the present study, we investigated whether transient receptor potential canonical channel-3 (TRPC3) may link vascular endothelial growth factor (VEGF) pathway to NFκB/ET B receptor axis in the rat piriform cortex during vasogenic edema formation. Following SE, TRPC3 and ET B receptor independently activated phosphatidylinositol 3 kinase (PI3K)/AKT/eNOS signaling pathway. SN50 (a NFκB inhibitor) attenuated the up-regulations of eNOS, TRPC3 and ET B receptor expressions following SE, accompanied by reductions in PI3K/AKT phosphorylations. Inhibition of SE-induced VEGF over-expression by leptomycin B also abrogated PI3K and AKT phosphorylations, but not TRPC3 expression. Wortmannin (a PI3K inhibitor) and 3CAI (an AKT inhibitor) effectively inhibited up-regulation of eNOS expressions and vasogenic edema lesion following SE. These findings indicate that PI3K/AKT may be common down-stream molecules for TRPC3- and ET B receptor signaling pathways during vasogenic edema formation. In addition, the present data demonstrate for the first time that TRPC3 may integrate VEGF- and NFκB-mediated vasogenic edema formation following SE. Thus, we suggest that PI3K/AKT signaling pathway may be one of considerable therapeutic targets for vasogenic edema. Copyright © 2017 Elsevier B.V. All rights reserved.

Double-stranded RNA-activated protein kinase is a key modulator of insulin sensitivity in physiological conditions and in obesity in mice.

PubMed

Carvalho-Filho, M A; Carvalho, B M; Oliveira, A G; Guadagnini, D; Ueno, M; Dias, M M; Tsukumo, D M; Hirabara, S M; Reis, L F; Curi, R; Carvalheira, J B C; Saad, Mario J A

2012-11-01

The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase β. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase β phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.

Neural substrates underlying fear-evoked freezing: the periaqueductal grey–cerebellar link

PubMed Central

Koutsikou, Stella; Crook, Jonathan J; Earl, Emma V; Leith, J Lianne; Watson, Thomas C; Lumb, Bridget M; Apps, Richard

2014-01-01

The central neural pathways involved in fear-evoked behaviour are highly conserved across mammalian species, and there is a consensus that understanding them is a fundamental step towards developing effective treatments for emotional disorders in man. The ventrolateral periaqueductal grey (vlPAG) has a well-established role in fear-evoked freezing behaviour. The neural pathways underlying autonomic and sensory consequences of vlPAG activation in fearful situations are well understood, but much less is known about the pathways that link vlPAG activity to distinct fear-evoked motor patterns essential for survival. In adult rats, we have identified a pathway linking the vlPAG to cerebellar cortex, which terminates as climbing fibres in lateral vermal lobule VIII (pyramis). Lesion of pyramis input–output pathways disrupted innate and fear-conditioned freezing behaviour. The disruption in freezing behaviour was strongly correlated to the reduction in the vlPAG-induced facilitation of α-motoneurone excitability observed after lesions of the pyramis. The increased excitability of α-motoneurones during vlPAG activation may therefore drive the increase in muscle tone that underlies expression of freezing behaviour. By identifying the cerebellar pyramis as a critical component of the neural network subserving emotionally related freezing behaviour, the present study identifies novel neural pathways that link the PAG to fear-evoked motor responses. PMID:24639484

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zheng Jun; Shin, Jung-Min; Choi, Dae-Kyoung

Psoriasis is a common skin disease, of which pathogenesis involves the increase of inflammatory reaction in epidermal cells. In an attempt to find therapeutics for psoriasis, we found that cucurbitacin B has an inhibitory potential on imiquimod-induced inflammation of keratinocytes. Cucurbitacin B significantly inhibited imiquimod-induced expression of crucial psoriatic cytokines, such as IL-8 and CCL20, via down-regulation of NF-κB and STAT3 signaling pathway in human keratinocytes. In addition, keratinocyte proliferation was markedly inhibited by cucurbitacin B. The potential beneficial effect of cucurbitacin B on psoriasis was further validated in imiquimod-induced psoriasiform dermatitis of experimental animal. Topical application of cucurbitacin Bmore » resulted in significant reduction of epidermal hyperplasia and inflammatory cytokines production, and ameliorated the psoriatic symptom. Taken together, these results suggest that cucurbitacin B may be a potential candidate for the treatment of psoriasis. - Highlights: • Cucurbitacin B has a potential for inhibiting the growth of keratinocytes. • Cucurbitacin B inhibits imiquimod-induced inflammatory reaction in keratinocytes. • Cucurbitacin B inhibits imiquimod-induced psoriasiform dermatitis in experimental animal.« less

Magnolol Nanoparticles Exhibit Improved Water Solubility and Suppress TNF-α-Induced VCAM-1 Expression in Endothelial Cells.

PubMed

Lee, Chiang-Wen; Hu, Stephen Chu-Sung; Yen, Feng-Lin; Hsu, Lee-Fen; Lee, I-Ta; Lin, Zih-Chan; Tsai, Ming-Horng; Huang, Chieh-Liang; Liang, Chan-Jung; Chiang, Yao-Chang

2017-03-01

The expression of the adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells enables the attachment of leukocytes to the endothelium, which may lead to inflammation and the development of atherosclerosis. Magnolol is a major bioactive compound derived from the plant species Magnolia officinalis. In this study, we synthesized a novel nanoparticle formulation of magnolol to improve its water solubility and physicochemical properties, evaluated its effects on TNF-α-induced VCAM-1 expression in endothelial cells, and determined the signal transduction pathways involved. Our findings demonstrated that the magnolol nanoparticle system showed great improvements in physicochemical properties and water solubility owing to a reduction in particle size, transformation from a crystalline to amorphous structure, and the formation of hydrogen bonds with the nanoparticle carriers. In terms of its biological actions, magnolol nanoparticles attenuated TNF-α-induced VCAM-1 protein expression, promoter activity, and mRNA expression in endothelial cells in vitro. This was found to be mediated by the ERK, AKT, and NF-κB signaling pathways. In addition, magnolol nanoparticles inhibited TNF-α-induced leukocyte adhesion to endothelial cells, and suppressed TNF-α-induced VCAM-1 expression in the aortic endothelium of mice. In summary, since magnolol nanoparticles inhibit endothelial VCAM-1 expression and leukocyte adhesion to endothelial cells, this novel drug formulation may be a potentially useful therapeutic formulation to prevent the development of atherosclerosis and inflammatory diseases.

Involvement of phosphoinositide 3-kinase and PTEN protein in mechanism of activation of TRPC6 protein in vascular smooth muscle cells.

PubMed

Monet, Michaël; Francoeur, Nancy; Boulay, Guylain

2012-05-18

TRPC6 is a cation channel in the plasma membrane that plays a role in Ca(2+) entry after the stimulation of a G(q)-protein-coupled or tyrosine-kinase receptor. TRPC6 translocates to the plasma membrane upon stimulation and remains there as long as the stimulus is present. However, the mechanism that regulates the trafficking and activation of TRPC6 are unclear. In this study we showed phosphoinositide 3-kinase and its antagonistic phosphatase, PTEN, are involved in the activation of TRPC6. The inhibition of PI3K by PIK-93, LY294002, or wortmannin decreased carbachol-induced translocation of TRPC6 to the plasma membrane and carbachol-induced net Ca(2+) entry into T6.11 cells. Conversely, a reduction of PTEN expression did not affect carbachol-induced externalization of TRPC6 but increased Ca(2+) entry through TRPC6 in T6.11 cells. We also showed that the PI3K/PTEN pathway regulates vasopressin-induced translocation of TRPC6 to the plasma membrane and vasopressin-induced Ca(2+) entry into A7r5 cells, which endogenously express TRPC6. In summary, we provided evidence that the PI3K/PTEN pathway plays an important role in the translocation of TRPC6 to the plasma membrane and may thus have a significant impact on Ca(2+) signaling in cells that endogenously express TRPC6.

Involvement of Phosphoinositide 3-Kinase and PTEN Protein in Mechanism of Activation of TRPC6 Protein in Vascular Smooth Muscle Cells*

PubMed Central

Monet, Michaël; Francoeur, Nancy; Boulay, Guylain

2012-01-01

TRPC6 is a cation channel in the plasma membrane that plays a role in Ca2+ entry after the stimulation of a Gq-protein-coupled or tyrosine-kinase receptor. TRPC6 translocates to the plasma membrane upon stimulation and remains there as long as the stimulus is present. However, the mechanism that regulates the trafficking and activation of TRPC6 are unclear. In this study we showed phosphoinositide 3-kinase and its antagonistic phosphatase, PTEN, are involved in the activation of TRPC6. The inhibition of PI3K by PIK-93, LY294002, or wortmannin decreased carbachol-induced translocation of TRPC6 to the plasma membrane and carbachol-induced net Ca2+ entry into T6.11 cells. Conversely, a reduction of PTEN expression did not affect carbachol-induced externalization of TRPC6 but increased Ca2+ entry through TRPC6 in T6.11 cells. We also showed that the PI3K/PTEN pathway regulates vasopressin-induced translocation of TRPC6 to the plasma membrane and vasopressin-induced Ca2+ entry into A7r5 cells, which endogenously express TRPC6. In summary, we provided evidence that the PI3K/PTEN pathway plays an important role in the translocation of TRPC6 to the plasma membrane and may thus have a significant impact on Ca2+ signaling in cells that endogenously express TRPC6. PMID:22493444

The pathological role of advanced glycation end products-downregulated heat shock protein 60 in islet β-cell hypertrophy and dysfunction.

PubMed

Guan, Siao-Syun; Sheu, Meei-Ling; Yang, Rong-Sen; Chan, Ding-Cheng; Wu, Cheng-Tien; Yang, Ting-Hua; Chiang, Chih-Kang; Liu, Shing-Hwa

2016-04-26

Heat shock protein 60 (HSP60) is a mitochondrial chaperone. Advanced glycation end products (AGEs) have been shown to interfere with the β-cell function. We hypothesized that AGEs induced β-cell hypertrophy and dysfunction through a HSP60 dysregulation pathway during the stage of islet/β-cell hypertrophy of type-2-diabetes. We investigated the role of HSP60 in AGEs-induced β-cell hypertrophy and dysfunction using the models of diabetic mice and cultured β-cells. Hypertrophy, increased levels of p27Kip1, AGEs, and receptor for AGEs (RAGE), and decreased levels of HSP60, insulin, and ATP content were obviously observed in pancreatic islets of 12-week-old db/db diabetic mice. Low-concentration AGEs significantly induced the cell hypertrophy, increased the p27Kip1 expression, and decreased the HSP60 expression, insulin secretion, and ATP content in cultured β-cells, which could be reversed by RAGE neutralizing antibody. HSP60 overexpression significantly reversed AGEs-induced hypertrophy, dysfunction, and ATP reduction in β-cells. Oxidative stress was also involved in the AGEs-decreased HSP60 expression in β-cells. Pancreatic sections from diabetic patient showed islet hypertrophy, increased AGEs level, and decreased HSP60 level as compared with normal subject. These findings highlight a novel mechanism by which a HSP60-correlated signaling pathway contributes to the AGEs-RAGE axis-induced β-cell hypertrophy and dysfunction under diabetic hyperglycemia.

The pathological role of advanced glycation end products-downregulated heat shock protein 60 in islet β-cell hypertrophy and dysfunction

PubMed Central

Wu, Cheng-Tien; Yang, Ting-Hua; Chiang, Chih-Kang; Liu, Shing-Hwa

2016-01-01

Heat shock protein 60 (HSP60) is a mitochondrial chaperone. Advanced glycation end products (AGEs) have been shown to interfere with the β-cell function. We hypothesized that AGEs induced β-cell hypertrophy and dysfunction through a HSP60 dysregulation pathway during the stage of islet/β-cell hypertrophy of type-2-diabetes. We investigated the role of HSP60 in AGEs-induced β-cell hypertrophy and dysfunction using the models of diabetic mice and cultured β-cells. Hypertrophy, increased levels of p27Kip1, AGEs, and receptor for AGEs (RAGE), and decreased levels of HSP60, insulin, and ATP content were obviously observed in pancreatic islets of 12-week-old db/db diabetic mice. Low-concentration AGEs significantly induced the cell hypertrophy, increased the p27Kip1 expression, and decreased the HSP60 expression, insulin secretion, and ATP content in cultured β-cells, which could be reversed by RAGE neutralizing antibody. HSP60 overexpression significantly reversed AGEs-induced hypertrophy, dysfunction, and ATP reduction in β-cells. Oxidative stress was also involved in the AGEs-decreased HSP60 expression in β-cells. Pancreatic sections from diabetic patient showed islet hypertrophy, increased AGEs level, and decreased HSP60 level as compared with normal subject. These findings highlight a novel mechanism by which a HSP60-correlated signaling pathway contributes to the AGEs-RAGE axis-induced β-cell hypertrophy and dysfunction under diabetic hyperglycemia. PMID:27056903

Eupafolin nanoparticles protect HaCaT keratinocytes from particulate matter-induced inflammation and oxidative stress

PubMed Central

Lin, Zih-Chan; Lee, Chiang-Wen; Tsai, Ming-Horng; Ko, Horng-Huey; Fang, Jia-You; Chiang, Yao-Chang; Liang, Chan-Jung; Hsu, Lee-Fen; Hu, Stephen Chu-Sung; Yen, Feng-Lin

2016-01-01

Exposure to particulate matter (PM), a major form of air pollution, can induce oxidative stress and inflammation and may lead to many diseases in various organ systems including the skin. Eupafolin, a flavonoid compound derived from Phyla nodiflora, has been previously shown to exhibit various pharmacological activities, including antioxidant and anti-inflammatory effects. Unfortunately, eupafolin is characterized by poor water solubility and skin penetration, which limits its clinical applications. To address these issues, we successfully synthesized a eupafolin nanoparticle delivery system (ENDS). Our findings showed that ENDS could overcome the physicochemical drawbacks of raw eupafolin with respect to water solubility and skin penetration, through reduction of particle size and formation of an amorphous state with hydrogen bonding. Moreover, ENDS was superior to raw eupafolin in attenuating PM-induced oxidative stress and inflammation in HaCaT keratinocytes, by mediating the antioxidant pathway (decreased reactive oxygen species production and nicotinamide adenine dinucleotide phosphate oxidase activity) and anti-inflammation pathway (decreased cyclooxygenase-2 expression and prostaglandin E2 production through downregulation of mitogen-activated protein kinase and nuclear factor-κB signaling). In summary, ENDS shows better antioxidant and anti-inflammatory activities than raw eupafolin through improvement of water solubility and skin penetration. Therefore, ENDS may potentially be used as a medicinal drug and/or cosmeceutical product to prevent PM-induced skin inflammation. PMID:27570454

Downregulation of miR-133 via MAPK/ERK signaling pathway involved in nicotine-induced cardiomyocyte apoptosis.

PubMed

Wang, Lu; Li, Xuelian; Zhou, Yuhong; Shi, Hui; Xu, Chaoqian; He, Hua; Wang, Shuxuan; Xiong, Xuehui; Zhang, Yong; Du, Zhimin; Zhang, Ruixue; Lu, Yanjie; Yang, Baofeng; Shan, Hongli

2014-02-01

Tobacco smoking is a risk factor for many diseases, and nicotine is a major component of tobacco. Our previous work revealed that nicotine can induce myocardial fibrosis. This study aimed to investigate whether nicotine can induce cardiomyocyte apoptosis and to explore the mechanisms involved. Cardiomyocytes were exposed to different nicotine concentrations for 48 h. MTT assay showed that the viability of cardiomyocytes was significantly inhibited by nicotine in a dose- and time-dependent manner. Loss of mitochondrial membrane potential, nuclear and DNA defragmentation determined by TUNEL and ELISA assays, and morphological alterations all revealed the pro-apoptotic property of nicotine. Meanwhile, miR-133, a muscle-specific microRNA, was markedly downregulated by nicotine. Consistently, caspase-9, a target gene for miR-133, was significantly upregulated, leading to an increase in caspase-3, in nicotine-treated cardiomyocytes compared to non-treated cells. Furthermore, ERK1/2 protein levels were considerably downregulated, along with reduction of serum response factor (SRF), which is a downstream target protein of ERK1/2 and an upstream transactivator of miR-133 as well. Our findings therefore revealed that inhibition of the ERK1/2-SRF-miR-133 signaling pathway to increase caspases-9 and -3 is a novel mechanism for nicotine to induce cardiomyocyte apoptosis and these tobacco smokers.

Epothilone B induces extrinsic pathway of apoptosis in human SKOV-3 ovarian cancer cells.

PubMed

Rogalska, Aneta; Gajek, Arkadiusz; Marczak, Agnieszka

2014-06-01

The molecular mechanisms underlying epothilone B (EpoB) induced apoptosis were investigated in SKOV-3 human ovarian cancer cells. The aim of this research was to compare EpoB's, which belongs to the new class of anticancer drugs, with paclitaxel's (PTX) ability to induce apoptosis. The mode of cell death was assessed colorimetrically, fluorimetrically and by immunoblot analyses through measuring DNA fragmentation, the level of intracellular calcium, the level of cytochrome c, TRAIL, the cleavage of poly(ADP-ribose) polymerase (PARP) and the activation of caspase-9, -8 and -3. EpoB leads to an increase of the cytosolic level of cytochrome c after 4 h of cell treatment. After 24 and 48 h of cell treatment the level of intracellular calcium also increased by about 21% and 24% respectively. Moreover, EpoB, similarly to PTX, promoted the expression of TRAIL in lymphocytes, although high TRAIL expression on tumor cells was detected only after adding EpoB to SKOV-3 cells. EpoB mediates caspases-8 and -3 activation, which is independent of the reduction in the amount of caspase-9. Epitope-specific monoclonal and polyclonal antibodies revealed characteristic apoptotic changes that included cleavage of the 116 kDa PARP polypeptide to 25 kDa fragments. The results of our study show that EpoB induces mainly the extrinsic pathway. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chronic restraint stress inhibits hair growth via substance P mediated by reactive oxygen species in mice.

PubMed

Liu, Nan; Wang, Lin-Hui; Guo, Ling-Ling; Wang, Guo-Qing; Zhou, Xi-Ping; Jiang, Yan; Shang, Jing; Murao, Koji; Chen, Jing-Wei; Fu, Wen-Qing; Zhang, Guo-Xing

2013-01-01

Solid evidence has demonstrated that psychoemotional stress induced alteration of hair cycle through neuropeptide substance P (SP) mediated immune response, the role of reactive oxygen species (ROS) in brain-skin-axis regulation system remains unknown. The present study aims to investigate possible mechanisms of ROS in regulation of SP-mast cell signal pathway in chronic restraint stress (CRS, a model of chronic psychoemotional stress) which induced abnormal of hair cycle. Our results have demonstrated that CRS actually altered hair cycle by inhibiting hair follicle growth in vivo, prolonging the telogen stage and delaying subsequent anagen and catagen stage. Up-regulation of SP protein expression in cutaneous peripheral nerve fibers and activation of mast cell were observed accompanied with increase of lipid peroxidation levels and reduction of the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in CRS mice skin. In addition, SP receptor antagonist (RP67580) reduced mast cell activations and lipid peroxidation levels as well as increased GSH-Px activity and normalized hair cycle. Furthermore, antioxidant Tempol (a free radical scavenger) also restored hair cycle, reduced SP protein expression and mast cell activation. Our study provides the first solid evidence for how ROS play a role in regulation of psychoemotional stress induced SP-Mast cell pathway which may provide a convincing rationale for antioxidant application in clinical treatment with psychological stress induced hair loss.

MicroRNA-30e promotes hepatocyte proliferation and inhibits apoptosis in cecal ligation and puncture-induced sepsis through the JAK/STAT signaling pathway by binding to FOSL2.

PubMed

Ling, Lan; Zhang, Shan-Hong; Zhi, Li-Da; Li, Hong; Wen, Qian-Kuan; Li, Gang; Zhang, Wen-Jia

2018-05-19

Hepatocyte proliferation and apoptosis are critical cellular behaviors in rat liver as a result of a liver injury. Herein, we performed this study in order to evaluate the role of miR-30e and its target Fos-Related Antigen-2 (FOSL2) in septic rats through the JAK/STAT signaling pathway. Rat models of sepsis were induced by cecal ligation and puncture. Enzyme-linked immunosorbent assay (ELISA) was performed to access serum levels of lipopolysaccharide (LPS), inflammatory factors, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) to confirm the successful establishment of the model. The hepatocytes were subject to miR-30e mimics, miR-30e inhibitors or siRNA-FOSL2. The expressions of miR-30e, FOSL2, apoptosis- and, JAK/STAT signaling pathway-related genes in liver tissues and hepatocytes were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. MTT assay and flow cytometry were performed to evaluate hepatocyte viability and apoptosis, respectively. The results obtained revealed that in the septic rats, serum levels of inflammatory factors, LPS, ALT and AST, as well as the expression of FOSL2 were elevated and the JAK/STAT signaling pathway was activated, while there was a reduction in the expression of miR-30e. An initial bioinformatics prediction followed by a confirmatory dual-luciferase reporter assay determined that miR-30e targeted and negatively regulated FOSL2 expression. MiR-30e inhibited the activation of JSK2/STAT3 signaling pathway by reducing FOSL2 expression, while miR-30e enhanced hepatocyte proliferation and decreased hepatocyte cell apoptosis in septic rats. These findings indicated that miR-30e may serve as an independent therapeutic target for sepsis, due to its ability to inhibit apoptosis and induce proliferation of hepatocytes by targeted inhibition of FOSL2 through the JAK/STAT signaling pathway. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Developmental dysplasia of the hip: A computational biomechanical model of the path of least energy for closed reduction.

PubMed

Zwawi, Mohammed A; Moslehy, Faissal A; Rose, Christopher; Huayamave, Victor; Kassab, Alain J; Divo, Eduardo; Jones, Brendan J; Price, Charles T

2017-08-01

This study utilized a computational biomechanical model and applied the least energy path principle to investigate two pathways for closed reduction of high grade infantile hip dislocation. The principle of least energy when applied to moving the femoral head from an initial to a final position considers all possible paths that connect them and identifies the path of least resistance. Clinical reports of severe hip dysplasia have concluded that reduction of the femoral head into the acetabulum may occur by a direct pathway over the posterior rim of the acetabulum when using the Pavlik harness, or by an indirect pathway with reduction through the acetabular notch when using the modified Hoffman-Daimler method. This computational study also compared the energy requirements for both pathways. The anatomical and muscular aspects of the model were derived using a combination of MRI and OpenSim data. Results of this study indicate that the path of least energy closely approximates the indirect pathway of the modified Hoffman-Daimler method. The direct pathway over the posterior rim of the acetabulum required more energy for reduction. This biomechanical analysis confirms the clinical observations of the two pathways for closed reduction of severe hip dysplasia. The path of least energy closely approximated the modified Hoffman-Daimler method. Further study of the modified Hoffman-Daimler method for reduction of severe hip dysplasia may be warranted based on this computational biomechanical analysis. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1799-1805, 2017. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.

Death receptor 6 induces apoptosis not through type I or type II pathways, but via a unique mitochondria-dependent pathway by interacting with Bax protein.

PubMed

Zeng, Linlin; Li, Ting; Xu, Derek C; Liu, Jennifer; Mao, Guozhang; Cui, Mei-Zhen; Fu, Xueqi; Xu, Xuemin

2012-08-17

Cells undergo apoptosis through two major pathways, the extrinsic pathway (death receptor pathway) and the intrinsic pathway (the mitochondrial pathway). These two pathways can be linked by caspase-8-activated truncated Bid formation. Very recently, death receptor 6 (DR6) was shown to be involved in the neurodegeneration observed in Alzheimer disease. DR6, also known as TNFRSF21, is a relatively new member of the death receptor family, and it was found that DR6 induces apoptosis when it is overexpressed. However, how the death signal mediated by DR6 is transduced intracellularly is not known. To this end, we have examined the roles of caspases, apoptogenic mitochondrial factor cytochrome c, and the Bcl-2 family proteins in DR6-induced apoptosis. Our data demonstrated that Bax translocation is absolutely required for DR6-induced apoptosis. On the other hand, inhibition of caspase-8 and knockdown of Bid have no effect on DR6-induced apoptosis. Our results strongly suggest that DR6-induced apoptosis occurs through a new pathway that is different from the type I and type II pathways through interacting with Bax.

The Use of Chemical Probes for the Characterization of the Predominant Abiotic Reductants in Anaerobic Sediments

EPA Science Inventory

Identifying the predominant chemical reductants and pathways for electron transfer in anaerobic systems is paramount to the development of environmental fate models that incorporate pathways for abiotic reductive transformations. Currently, such models do not exist. In this chapt...

Inverse kinetic solvent isotope effect in TiO2 photocatalytic dehalogenation of non-adsorbable aromatic halides: a proton-induced pathway.

PubMed

Chang, Wei; Sun, Chunyan; Pang, Xibin; Sheng, Hua; Li, Yue; Ji, Hongwei; Song, Wenjing; Chen, Chuncheng; Ma, Wanhong; Zhao, Jincai

2015-02-09

An efficient redox reaction between organic substrates in solution and photoinduced h(+) vb /e(-) cb on the surface of photocatalysts requires the substrates or solvent to be adsorbed onto the surface, and is consequentially marked by a normal kinetic solvent isotope effect (KSIE ≥ 1). Reported herein is a universal inverse KSIE (0.6-0.8 at 298 K) for the reductive dehalogenation of aromatic halides which cannot adsorb onto TiO2 in a [D0 ]methanol/[D4 ]methanol solution. Combined with in situ ATR-FTIR spectroscopy investigations, a previously unknown pathway for the transformation of these aromatic halides in TiO2 photocatalysis was identified: a proton adduct intermediate, induced by released H(+) /D(+) from solvent oxidation, accompanies a change in hybridization from sp(2) to sp(3) at a carbon atom of the aromatic halides. The protonation event leads these aromatic halides to adsorb onto the TiO2 surface and an ET reaction to form dehalogenated products follows. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Attenuation of the programmed cell death-1 pathway increases the M1 polarization of macrophages induced by zymosan

PubMed Central

Chen, W; Wang, J; Jia, L; Liu, J; Tian, Y

2016-01-01

Programmed cell death-1 (PD-1) is a member of the CD28 superfamily that delivers negative signals on interaction with its 2 ligands, PD-L1 and PD-L2. We assessed the contribution of the PD-1 pathway to regulating the polarization of macrophages that promote inflammation induced by zymosan. We found that PD-1−/− mice developed robust peritonitis with more abundant infiltration of M1 macrophages, accompanied by higher levels of pro-inflammation factors, especially monocyte chemotactic protein-1 (MCP-1) compared with wild-type controls ex vivo and in vitro. Our results indicated that PD-1 deficiency promotes M1 rather than M2 polarization of macrophages by enhancing the expression of p-STAT1/p-NF-κB p65 and downregulating p-STAT6. We found that PD-1 engagement followed by zymosan stimulation might primarily attenuate the phosphorylation of tyrosine residue in PD-1 receptor/ligand and the recruitment of SHP-2 to PD-1 receptor/ligand, leading to the reduction of M1 type cytokine production. PMID:26913605

Grb2 regulates B-cell maturation, B-cell memory responses and inhibits B-cell Ca2+ signalling.

PubMed

Ackermann, Jochen A; Radtke, Daniel; Maurberger, Anna; Winkler, Thomas H; Nitschke, Lars

2011-04-20

Grb2 is a ubiquitously expressed adaptor protein, which activates Ras and MAP kinases in growth factor receptor signalling, while in B-cell receptor (BCR) signalling this role is controversial. In B cell lines it was shown that Grb2 can inhibit BCR-induced Ca(2+) signalling. Nonetheless, the physiological role of Grb2 in primary B cells is still unknown. We generated a B-cell-specific Grb2-deficient mouse line, which had a severe reduction of mature follicular B cells in the periphery due to a differentiation block and decreased B-cell survival. Moreover, we found several changes in important signalling pathways: enhanced BCR-induced Ca(2+) signalling, alterations in mitogen-activated protein kinase activation patterns and strongly impaired Akt activation, the latter pointing towards a defect in PI3K signalling. Interestingly, B-cell-specific Grb2-deficient mice showed impaired IgG and B-cell memory responses, and impaired germinal centre formation. Thus, Grb2-dependent signalling pathways are crucial for lymphocyte differentiation processes, as well as for control of secondary humoral immune responses.

Jasmonic acid-mediated defense suppresses brassinosteroid-mediated susceptibility to Rice black streaked dwarf virus infection in rice.

PubMed

He, Yuqing; Zhang, Hehong; Sun, Zongtao; Li, Junmin; Hong, Gaojie; Zhu, Qisong; Zhou, Xuebiao; MacFarlane, Stuart; Yan, Fei; Chen, Jianping

2017-04-01

Plant hormones play a vital role in plant immune responses. However, in contrast to the relative wealth of information on hormone-mediated immunity in dicot plants, little information is available on monocot-virus defense systems. We used a high-throughput-sequencing approach to compare the global gene expression of Rice black-streaked dwarf virus (RBSDV)-infected rice plants with that of healthy plants. Exogenous hormone applications and transgenic rice were used to test RBSDV infectivity and pathogenicity. Our results revealed that the jasmonic acid (JA) pathway was induced while the brassinosteroid (BR) pathway was suppressed in infected plants. Foliar application of methyl jasmonate (MeJA) or brassinazole (BRZ) resulted in a significant reduction in RBSDV incidence, while epibrassinolide (BL) treatment increased RBSDV infection. Infection studies using coi1-13 and Go mutants demonstrated JA-mediated resistance and BR-mediated susceptibility to RBSDV infection. A mixture of MeJA and BL treatment resulted in a significant reduction in RBSDV infection compared with a single BL treatment. MeJA application efficiently suppressed the expression of BR pathway genes, and this inhibition depended on the JA coreceptor OsCOI1. Collectively, our results reveal that JA-mediated defense can suppress the BR-mediated susceptibility to RBSDV infection. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

High-throughput screening for cellobiose dehydrogenases by Prussian Blue in situ formation.

PubMed

Vasilchenko, Liliya G; Ludwig, Roland; Yershevich, Olga P; Haltrich, Dietmar; Rabinovich, Mikhail L

2012-07-01

Extracellular fungal flavocytochrome cellobiose dehydrogenase (CDH) is a promising enzyme for both bioelectronics and lignocellulose bioconversion. A selective high-throughput screening assay for CDH in the presence of various fungal oxidoreductases was developed. It is based on Prussian Blue (PB) in situ formation in the presence of cellobiose (<0.25 mM), ferric acetate, and ferricyanide. CDH induces PB formation via both reduction of ferricyanide to ferrocyanide reacting with an excess of Fe³⁺ (pathway 1) and reduction of ferric ions to Fe²⁺ reacting with the excess of ferricyanide (pathway 2). Basidiomycetous and ascomycetous CDH formed PB optimally at pH 3.5 and 4.5, respectively. In contrast to the holoenzyme CDH, its FAD-containing dehydrogenase domain lacking the cytochrome domain formed PB only via pathway 1 and was less active than the parent enzyme. The assay can be applied on active growing cultures on agar plates or on fungal culture supernatants in 96-well plates under aerobic conditions. Neither other carbohydrate oxidoreductases (pyranose dehydrogenase, FAD-dependent glucose dehydrogenase, glucose oxidase) nor laccase interfered with CDH activity in this assay. Applicability of the developed assay for the selection of new ascomycetous CDH producers as well as possibility of the controlled synthesis of new PB nanocomposites by CDH are discussed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Involvement of PI3K/AKT and MAPK Pathways for TNF-α Production in SiHa Cervical Mucosal Epithelial Cells Infected with Trichomonas vaginalis.

PubMed

Yang, Jung-Bo; Quan, Juan-Hua; Kim, Ye-Eun; Rhee, Yun-Ee; Kang, Byung-Hyun; Choi, In-Wook; Cha, Guang-Ho; Yuk, Jae-Min; Lee, Young-Ha

2015-08-01

Trichomonas vaginalis; induces proinflammation in cervicovaginal mucosal epithelium. To investigate the signaling pathways in TNF-α production in cervical mucosal epithelium after T. vaginalis infection, the phosphorylation of PI3K/AKT and MAPK pathways were evaluated in T. vaginalis-infected SiHa cells in the presence and absence of specific inhibitors. T. vaginalis increased TNF-α production in SiHa cells, in a parasite burden-dependent and incubation time-dependent manner. In T. vaginalis-infected SiHa cells, AKT, ERK1/2, p38 MAPK, and JNK were phosphorylated from 1 hr after infection; however, the phosphorylation patterns were different from each other. After pretreatment with inhibitors of the PI3K/AKT and MAPK pathways, TNF-α production was significantly decreased compared to the control; however, TNF-α reduction patterns were different depending on the type of PI3K/MAPK inhibitors. TNF-α production was reduced in a dose-dependent manner by treatment with wortmannin and PD98059, whereas it was increased by SP600125. These data suggested that PI3K/AKT and MAPK signaling pathways are important in regulation of TNF-α production in cervical mucosal epithelial SiHa cells. However, activation patterns of each pathway were different from the types of PI3K/MAPK pathways.

Effect of Wnt-1 inducible signaling pathway protein-2 (WISP-2/CCN5), a downstream protein of Wnt signaling, on adipocyte differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inadera, Hidekuni; Shimomura, Akiko; Tachibana, Shinjiro

2009-02-20

Wnt signaling negatively regulates adipocyte differentiation, and ectopic expression of Wnt-1 in 3T3-L1 cells induces several downstream molecules of Wnt signaling, including Wnt-1 inducible signaling pathway protein (WISP)-2. In this study, we examined the role of WISP-2 in the process of adipocyte differentiation using an in vitro cell culture system. In the differentiation of 3T3-L1 cells, WISP-2 expression was observed in growing cells and declined thereafter. In the mitotic clonal expansion phase of adipocyte differentiation, WISP-2 expression was transiently down-regulated concurrently with up-regulation of CCAAT/enhancer-binding protein {delta} expression. Treatment of 3T3-L1 cells in the differentiation medium with lithium, an activatormore » of Wnt signaling, inhibited the differentiation process with concomitant induction of WISP-2. Treatment of differentiated cells with lithium induced de-differentiation as evidenced by profound reduction of peroxisome proliferator-activator receptor {gamma} expression and concomitant induction of WISP-2. However, de-differentiation of differentiated cells induced by tumor necrosis factor-{alpha} did not induce WISP-2 expression. To directly examine the effect of WISP-2 on adipocyte differentiation, 3T3-L1 cells were infected with a retrovirus carrying WISP-2. Although forced expression of WISP-2 inhibited preadipocyte proliferation, it had no effect on adipocyte differentiation. Thus, although WISP-2 is a downstream protein of Wnt signaling, the role of WISP-2 on adipocyte differentiation may be marginal, at least in this in vitro culture model.« less

A novel peptide, colivelin, prevents alcohol-induced apoptosis in fetal brain of C57BL/6 mice: signaling pathway investigations

PubMed Central

Sari, Youssef; Chiba, Tomohiro; Yamada, Marina; Rebec, George V.; Aiso, Sadakazu

2009-01-01

Fetal alcohol exposure is known to induce cell death through apoptosis. We found that colivelin (CLN), a novel peptide with the sequence SALLRSIPAPAGASRLLLLTGEIDLP, prevents this apoptosis. Our initial experiment revealed that CLN enhanced the viability of primary cortical neurons exposed to alcohol. We then used a mouse model of fetal alcohol exposure to identify the intracellular mechanisms underlying these neuroprotective effects. On embryonic day 7 (E7), weight-matched pregnant females were assigned to the following groups: (1) ethanol liquid diet (ALC) 25% (4.49%, v/v) ethanol derived calories; (2) pair-fed control; (3) normal chow; (4) ALC combined with administration (i.p.) of CLN (20 μg/20 g body weight); and (5) pair-fed combined with administration (i.p.) of CLN (20 μg/20 g body weight). On E13, fetal brains were collected and assayed for TUNEL staining, caspase-3 colorimetric assay, ELISA, and MSD electrochemiluminescence. CLN blocked the alcohol-induced decline in brain weight and prevented alcohol-induced: apoptosis, activation of caspase-3 and increases of cytosolic cytochrome c, and decreases of mitochondrial cytochrome c. Analysis of proteins in the upstream signaling pathway revealed that CLN down-regulated the phosphorylation of the c-Jun N-terminal kinase. Moreover, CLN prevented alcohol-induced reduction in phosphorylation of BAD protein. Thus, CLN appears to act directly on upstream signaling proteins to prevent alcohol-induced apoptosis. Further assessment of these proteins and their signaling mechanisms is likely to enhance development of neuroprotective therapies. PMID:19782727

Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu

Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD.more » Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.« less

Oxaliplatin-induced blood brain barrier loosening: a new point of view on chemotherapy-induced neurotoxicity

PubMed Central

Valerio Branca, Jacopo Junio; Maresca, Mario; Morucci, Gabriele; Becatti, Matteo; Paternostro, Ferdinando; Gulisano, Massimo; Ghelardini, Carla; Salvemini, Daniela

2018-01-01

Oxaliplatin is a key drug in the treatment of advanced metastatic colorectal cancer. Despite its beneficial effects in tumor reduction, the most prevalent side-effect of oxaliplatin treatment is a chemotherapy-induced neuropathy that frequently forces to discontinue the therapy. Indeed, along with direct damage to peripheral nerves, the chemotherapy-related neurotoxicity involves also the central nervous system (CNS) as demonstrated by pain chronicity and cognitive impairment (also known as chemobrain), a newly described pharmacological side effect. The presence of the blood brain barrier (BBB) is instrumental in preventing the entry of the drug into the CNS; here we tested the hypothesis that oxaliplatin might enter the endothelial cells of the BBB vessels and trigger a signaling pathway that induce the disassembly of the tight junctions, the critical components of the BBB integrity. By using a rat brain endothelial cell line (RBE4) we investigated the signaling pathway that ensued the entry of oxaliplatin within the cell. We found that the administration of 10 μM oxaliplatin for 8 and 16 h induced alterations of the tight junction (TJs) proteins zonula occludens-1 (ZO-1) and of F-actin, thus highlighting BBB alteration. Furthermore, we reported that intracellular oxaliplatin rapidly induced increased levels of reactive oxygen species and endoplasmic reticulum stress, assessed by the evaluation of glucose-regulated protein GRP78 expression levels. These events were accompanied by activation of caspase-3 that led to extracellular ATP release. These findings suggested a possible novel mechanism of action for oxaliplatin toxicity that could explain, at least in part, the chemotherapy-related central effects.

A Review of Mental Health and Mental Health Care Disparities Research: 2011-2014.

PubMed

Cook, Benjamin Lê; Hou, Sherry Shu-Yeu; Lee-Tauler, Su Yeon; Progovac, Ana Maria; Samson, Frank; Sanchez, Maria Jose

2018-06-01

Racial/ethnic minorities in the United States are more likely than Whites to have severe and persistent mental disorders and less likely to access mental health care. This comprehensive review evaluates studies of mental health and mental health care disparities funded by the National Institute of Mental Health (NIMH) to provide a benchmark for the 2015 NIMH revised strategic plan. A total of 615 articles were categorized into five pathways underlying mental health care and three pathways underlying mental health disparities. Identified studies demonstrate that socioeconomic mechanisms and demographic moderators of disparities in mental health status and treatment are well described, as are treatment options that support diverse patient needs. In contrast, there is a need for studies that focus on community- and policy-level predictors of mental health care disparities, link discrimination- and trauma-induced neurobiological pathways to disparities in mental illness, assess the cost effectiveness of disparities reduction programs, and scale up culturally adapted interventions.

A Computer Simulation Approach to Assessing Therapeutic Intervention Points for the Prevention of Cytokine-Induced Cartilage Breakdown

PubMed Central

Proctor, CJ; Macdonald, C; Milner, JM; Rowan, AD; Cawston, TE

2014-01-01

Objective To use a novel computational approach to examine the molecular pathways involved in cartilage breakdown and to use computer simulation to test possible interventions for reducing collagen release. Methods We constructed a computational model of the relevant molecular pathways using the Systems Biology Markup Language, a computer-readable format of a biochemical network. The model was constructed using our experimental data showing that interleukin-1 (IL-1) and oncostatin M (OSM) act synergistically to up-regulate collagenase protein levels and activity and initiate cartilage collagen breakdown. Simulations were performed using the COPASI software package. Results The model predicted that simulated inhibition of JNK or p38 MAPK, and overexpression of tissue inhibitor of metalloproteinases 3 (TIMP-3) led to a reduction in collagen release. Overexpression of TIMP-1 was much less effective than that of TIMP-3 and led to a delay, rather than a reduction, in collagen release. Simulated interventions of receptor antagonists and inhibition of JAK-1, the first kinase in the OSM pathway, were ineffective. So, importantly, the model predicts that it is more effective to intervene at targets that are downstream, such as the JNK pathway, rather than those that are close to the cytokine signal. In vitro experiments confirmed the effectiveness of JNK inhibition. Conclusion Our study shows the value of computer modeling as a tool for examining possible interventions by which to reduce cartilage collagen breakdown. The model predicts that interventions that either prevent transcription or inhibit the activity of collagenases are promising strategies and should be investigated further in an experimental setting. PMID:24757149

Intensive cardiovascular risk reduction induces sustainable changes in expression of genes and pathways important to vascular function.

PubMed

Ellsworth, Darrell L; Croft, Daniel T; Weyandt, Jamie; Sturtz, Lori A; Blackburn, Heather L; Burke, Amy; Haberkorn, Mary Jane; McDyer, Fionnuala A; Jellema, Gera L; van Laar, Ryan; Mamula, Kimberly A; Chen, Yaqin; Vernalis, Marina N

2014-04-01

Healthy lifestyle changes are thought to mediate cardiovascular disease risk through pathways affecting endothelial function and progression of atherosclerosis; however, the extent, persistence, and clinical significance of molecular change during lifestyle modification are not well known. We examined the effect of a rigorous cardiovascular disease risk reduction program on peripheral blood gene expression profiles in 63 participants and 63 matched controls to characterize molecular responses and identify regulatory pathways important to cardiovascular health. Dramatic changes in dietary fat intake (-61%; P<0.001 versus controls) and physical fitness (+34%; P<0.001) led to significant improvements in cardiovascular disease risk factors. Analysis of variance with false discovery rate correction for multiple testing (P<0.05) identified 26 genes after 12 weeks and 143 genes after 52 weeks that were differentially expressed from baseline in participants. Controls showed little change in cardiovascular disease risk factors or gene expression. Quantitative reverse transcription polymerase chain reaction validated differential expression for selected transcripts. Lifestyle modification effectively reduced expression of proinflammatory genes associated with neutrophil activation and molecular pathways important to vascular function, including cytokine production, carbohydrate metabolism, and steroid hormones. Prescription medications did not significantly affect changes in gene expression. Successful and sustained modulation of gene expression through lifestyle changes may have beneficial effects on the vascular system not apparent from traditional risk factors. Healthy lifestyles may restore homeostasis to the leukocyte transcriptome by downregulating lactoferrin and other genes important in the pathogenesis of atherosclerosis. Clinical Trial Registration- URL: www.clinicaltrials.gov. Unique identifier: NCT01805492.

Pharmacogenetics of ribavirin-induced anemia in hepatitis C.

PubMed

Ampuero, Javier; Romero-Gómez, Manuel

2016-09-01

Pharmacogenetics assesses inherited genetic differences in drug metabolic pathways and its role in medicine is growing. Ribavirin (RBV) and peginterferon were the standard of care therapy in hepatitis C virus infection during 15 years, with the addition of first-generation protease inhibitors at the beginning of 2010s. New direct-acting agents are the new standard of care, but RBV remains important in some scenarios. The main adverse effect of RBV is anemia, which requires dose reduction and even stopping treatment in some patients. Pharmacogenetics has identified ITPA and SLC28/29 genes to be closely related to RBV-induced anemia. The routine evaluation of these genes could help to identify those patients at risk of developing anemia during the hepatitis C virus treatment.

The melanocortinergic pathway is rapidly recruited by emotional stress and contributes to stress-induced anorexia and anxiety-like behavior.

PubMed

Liu, Jing; Garza, Jacob C; Truong, Ha V; Henschel, John; Zhang, Wei; Lu, Xin-Yun

2007-11-01

Neurons producing melanocortin receptor agonist, alpha-MSH derived from proopiomelanocortin, and antagonist, agouti-related protein, are known to be sensitive to metabolic stress such as food deprivation and glucoprivation. However, how these neurons respond to emotional/psychological stress remained to be elucidated. We report here that acute emotional stressors, i.e. restraint and forced swim, evoked mRNA expression of c-fos, a neuronal activation marker, in a high percentage of proopiomelanocortin neurons (up to 53% for restraint stress and 62% for forced swim), with marked variations along the rostro-caudal axis of the arcuate nucleus. In contrast, only a small population of agouti-related protein neurons in this brain region was activated. These neuronal activation patterns were correlated with behavioral reactions. Both stressors suppressed feeding and induced anxiety-like behavior in the elevated plus-maze test, as reflected by a reduction in the percentage of entries and time spent in the open arms. Central pretreatment with SHU9119, a melanocortin receptor antagonist, dose dependently attenuated the anorectic and anxiogenic effects elicited by acute restraint or forced swim. These results indicate that the melancortinergic pathway can be rapidly recruited by acute emotional stress, and that activation of melanocortin signaling is involved in mediating stress-induced anorexia and anxiety.

Accessory proteins 8b and 8ab of severe acute respiratory syndrome coronavirus suppress the interferon signaling pathway by mediating ubiquitin-dependent rapid degradation of interferon regulatory factor 3.

PubMed

Wong, Hui Hui; Fung, To Sing; Fang, Shouguo; Huang, Mei; Le, My Tra; Liu, Ding Xiang

2018-02-01

Severe acute respiratory syndrome coronavirus (SARS-CoV) is an inefficient inducer of interferon (IFN) response. It expresses various proteins that effectively circumvent IFN production at different levels via distinct mechanisms. Through the construction of recombinant IBV expressing proteins 8a, 8b and 8ab encoded by SARS-CoV ORF8, we demonstrate that expression of 8b and 8ab enables the corresponding recombinant viruses to partially overcome the inhibitory actions of IFN activation to achieve higher replication efficiencies in cells. We also found that proteins 8b and 8ab could physically interact with IRF3. Overexpression of 8b and 8ab resulted in the reduction of poly (I:C)-induced IRF3 dimerization and inhibition of the IFN-β signaling pathway. This counteracting effect was partially mediated by protein 8b/8ab-induced degradation of IRF3 in a ubiquitin-proteasome-dependent manner. Taken together, we propose that SARS-CoV may exploit the unique functions of proteins 8b and 8ab as novel mechanisms to overcome the effect of IFN response during virus infection. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification and characterization of a bacterial hydrosulphide ion channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czyzewski, Bryan K.; Wang, Da-Neng

2012-10-26

The hydrosulphide ion (HS{sup -}) and its undissociated form, hydrogen sulphide (H{sub 2}S), which are believed to have been critical to the origin of life on Earth, remain important in physiology and cellular signalling. As a major metabolite in anaerobic bacterial growth, hydrogen sulphide is a product of both assimilatory and dissimilatory sulphate reduction. These pathways can reduce various oxidized sulphur compounds including sulphate, sulphite and thiosulphate. The dissimilatory sulphate reduction pathway uses this molecule as the terminal electron acceptor for anaerobic respiration, in which process it produces excess amounts of H{sub 2}S. The reduction of sulphite is a keymore » intermediate step in all sulphate reduction pathways. In Clostridium and Salmonella, an inducible sulphite reductase is directly linked to the regeneration of NAD{sup +}, which has been suggested to have a role in energy production and growth, as well as in the detoxification of sulphite. Above a certain concentration threshold, both H{sub 2}S and HS{sup -} inhibit cell growth by binding the metal centres of enzymes and cytochrome oxidase, necessitating a release mechanism for the export of this toxic metabolite from the cell. Here we report the identification of a hydrosulphide ion channel in the pathogen Clostridium difficile through a combination of genetic, biochemical and functional approaches. The HS{sup -} channel is a member of the formate/nitrite transport family, in which about 50 hydrosulphide ion channels form a third subfamily alongside those for formate (FocA) and for nitrite (NirC). The hydrosulphide ion channel is permeable to formate and nitrite as well as to HS{sup -} ions. Such polyspecificity can be explained by the conserved ion selectivity filter observed in the channel's crystal structure. The channel has a low open probability and is tightly regulated, to avoid decoupling of the membrane proton gradient.« less

Peripheral α2-β1 adrenergic interactions mediate the ghrelin response to brain urocortin 1 in rats

PubMed Central

Yakabi, Koji; Harada, Yumi; Takayama, Kiyoshige; Ro, Shoki; Ochiai, Mitsuko; lizuka, Seiichi; Hattori, Tomohisa; Wang, Lixin; Taché, Yvette

2018-01-01

Summary The autonomic nervous system (ANS) conveys neuronal input from the brain to the stomach. We investigated mechanisms through which urocortin 1 (UCN1) injected intracerebroventricularly (ICV, 300 pmol/rat) inhibits circulating ghrelin in rats. This was achieved by assessing (1) the induction of c-fos gene expression as a marker of neuronal activation in specific hypothalamic and caudal brainstem regulating ANS; (2) the influence of vagotomy and pharmacological blockade of central and peripheral α- and β-adrenergic receptor (AR) on ICV UCN1 -induced reduction of plasma ghrelin levels (determined by ELISA); and (3) the relevance of this pathway in the feeding response to a fast in rats. UCN1 increased c-fos mRNA expression in key brain sites influencing sympathetic activity namely the hypothalamic paraventricular and ventromedial nuclei, locus coeruleus, nucleus of the solitary tract, and rostral ventrolateral medulla, by 16-, 29-, 6-, 37-, and 13-fold, respectively. In contrast, the dorsal motor nucleus of the vagus had little c-fos mRNA expression and ICV UCN1 induced a similar reduction in acylated ghrelin in the sham-operated (31%) and vagotomized (41%) rats. An intraperitoneal (IP) injection of either a non-selective α- or selective α2-AR antagonist reduced, while a selective α2-AR agonist enhanced ICV UCN1-induced suppression of plasma acylated ghrelin levels. In addition, IP injection of a non-selective β- or selective β1-AR agonist blocked, and selective β1-AR antagonist augmented, the ghrelin response to ICV UCN1. The IP injections of a selective α1- or non-selective β or β2-AR antagonists, or any of the pretreatments given ICV had no effect. ICV UCN1 reduced the 2-h food intake in response to a fast by 80%, and this effect was partially prevented by a selective α2-AR antagonist. These data suggest that ICV UCN1 reduces plasma ghrelin mainly through the brain sympathetic component of the ANS and peripheral AR specifically α2-AR activation and inactivation of β1-AR. The α2-AR pathway contributes to the associated reduction in food intake. PMID:25265283

Virus-Induced Silencing of Key Genes Leads to Differential Impact on Withanolide Biosynthesis in the Medicinal Plant, Withania somnifera.

PubMed

Agarwal, Aditya Vikram; Singh, Deeksha; Dhar, Yogeshwar Vikram; Michael, Rahul; Gupta, Parul; Chandra, Deepak; Trivedi, Prabodh Kumar

2018-02-01

Withanolides are a collection of naturally occurring, pharmacologically active, secondary metabolites synthesized in the medicinally important plant, Withania somnifera. These bioactive molecules are C28-steroidal lactone triterpenoids and their synthesis is proposed to take place via the mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways through the sterol pathway using 24-methylene cholesterol as substrate flux. Although the phytochemical profiles as well as pharmaceutical activities of Withania extracts have been well studied, limited genomic information and difficult genetic transformation have been a major bottleneck towards understanding the participation of specific genes in withanolide biosynthesis. In this study, we used the Tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) approach to study the participation of key genes from MVA, MEP and triterpenoid biosynthesis for their involvement in withanolide biosynthesis. TRV-infected W. somnifera plants displayed unique phenotypic characteristics and differential accumulation of total Chl as well as carotenoid content for each silenced gene suggesting a reduction in overall isoprenoid synthesis. Comprehensive expression analysis of putative genes of withanolide biosynthesis revealed transcriptional modulations conferring the presence of complex regulatory mechanisms leading to withanolide biosynthesis. In addition, silencing of genes exhibited modulated total and specific withanolide accumulation at different levels as compared with control plants. Comparative analysis also suggests a major role for the MVA pathway as compared with the MEP pathway in providing substrate flux for withanolide biosynthesis. These results demonstrate that transcriptional regulation of selected Withania genes of the triterpenoid biosynthetic pathway critically affects withanolide biosynthesis, providing new horizons to explore this process further, in planta.

PCB 126 toxicity is modulated by cross-talk between caveolae and Nrf2 signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petriello, Michael C.; University of Kentucky Superfund Research Center, Lexington, KY 40536; Han, Sung Gu

2014-06-01

Environmental toxicants such as polychlorinated biphenyls (PCBs) have been implicated in the promotion of multiple inflammatory disorders including cardiovascular disease, but information regarding mechanisms of toxicity and cross-talk between relevant cell signaling pathways is lacking. To examine the hypothesis that cross-talk between membrane domains called caveolae and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways alters PCB-induced inflammation, caveolin-1 was silenced in vascular endothelial cells, resulting in a decreased PCB-induced inflammatory response. Cav-1 silencing (siRNA treatment) also increased levels of Nrf2-ARE transcriptional binding, resulting in higher mRNA levels of the antioxidant genes glutathione s-transferase and NADPH dehydrogenase quinone-1 in both vehiclemore » and PCB-treated systems. Along with this upregulated antioxidant response, Cav-1 siRNA treated cells exhibited decreased mRNA levels of the Nrf2 inhibitory protein Keap1 in both vehicle and PCB-treated samples. Silencing Cav-1 also decreased protein levels of Nrf2 inhibitory proteins Keap1 and Fyn kinase, especially in PCB-treated cells. Further, endothelial cells from wildtype and Cav-1 −/− mice were isolated and treated with PCB to better elucidate the role of functional caveolae in PCB-induced endothelial inflammation. Cav-1 −/− endothelial cells were protected from PCB-induced cellular dysfunction as evidenced by decreased vascular cell adhesion molecule (VCAM-1) protein induction. Compared to wildtype cells, Cav-1 −/− endothelial cells also allowed for a more effective antioxidant response, as observed by higher levels of the antioxidant genes. These data demonstrate novel cross-talk mechanisms between Cav-1 and Nrf2 and implicate the reduction of Cav-1 as a protective mechanism for PCB-induced cellular dysfunction and inflammation. - Highlights: • Reduction of caveolin-1 protein protects against polychlorinated biphenyl toxicity. • Decreasing caveolin-1 levels increases the Nrf2 antioxidant response. • Reducing caveolin-1 levels decreases expression of Nrf2 inhibitory proteins. • Caveolin-1/Nrf2 cross-talk is evident in mouse, human, and porcine endothelial cells.« less

Selenium reduces the proapoptotic signaling associated to NF-kappaB pathway and stimulates glutathione peroxidase activity during excitotoxic damage produced by quinolinate in rat corpus striatum.

PubMed

Santamaría, Abel; Vázquez-Román, Beatriz; La Cruz, Verónica Pérez-De; González-Cortés, Carolina; Trejo-Solís, Ma Cristina; Galván-Arzate, Sonia; Jara-Prado, Aurelio; Guevara-Fonseca, Jorge; Ali, Syed F

2005-12-15

Quinolinate (QUIN) neurotoxicity has been attributed to degenerative events in nerve tissue produced by sustained activation of N-methyl-D-aspartate receptor (NMDAr) and oxidative stress. We have recently described the protective effects that selenium (Se), an antioxidant, produces on different markers of QUIN-induced neurotoxicity (Santamaría et al., 2003, J Neurochem 86:479-488.). However, the mechanisms by which Se exerts its protective actions remain unclear. Since some of these events are thought to be related with inhibition of deadly molecular cascades through the activation of antioxidant selenoproteins, in this study we investigated the effects of Se on QUIN-induced cell damage elicited by the nuclear factor kappaB (NF-kappaB) pathway, as well as the time-course response of striatal glutathione peroxidase (GPx) activity. Se (sodium selenite, 0.625 mg/kg/day, i.p.) was administered to rats for 5 days, and 120 min after the last administration, animals received a single striatal injection of QUIN (240 nmol/mul). Twenty-four hours later, their striata were tested for the expression of IkappaB-alpha (the NF-kappaB cytosolic binding protein), the immunohistochemical expression of NF-kappaB (evidenced as nuclear expression of P65), caspase-3-like activation, and DNA fragmentation. Additional groups were killed at 2, 6, and 24 h for measurement of GPx activity. Se reduced the QUIN-induced decrease in IkappaB-alpha expression, evidencing a reduction in its cytosolic degradation. Se also prevented the QUIN-induced increase in P65-immunoreactive cells, suggesting a reduction of NF-kappaB nuclear translocation. Caspase-3-like activation and DNA fragmentation produced by QUIN were also inhibited by Se. Striatal GPx activity was stimulated by Se at 2 and 6 h, but not at 24 h postlesion. Altogether, these data suggest that the protective effects exerted by Se on QUIN-induced neurotoxicity are partially mediated by the inhibition of proapoptotic events underlying IkappaB-alpha degradation, NF-kappaB nuclear translocation, and caspase-3-like activation in the rat striatum, probably involving the early activation of GPx.

Auditory Cortex Basal Activity Modulates Cochlear Responses in Chinchillas

PubMed Central

León, Alex; Elgueda, Diego; Silva, María A.; Hamamé, Carlos M.; Delano, Paul H.

2012-01-01

Background The auditory efferent system has unique neuroanatomical pathways that connect the cerebral cortex with sensory receptor cells. Pyramidal neurons located in layers V and VI of the primary auditory cortex constitute descending projections to the thalamus, inferior colliculus, and even directly to the superior olivary complex and to the cochlear nucleus. Efferent pathways are connected to the cochlear receptor by the olivocochlear system, which innervates outer hair cells and auditory nerve fibers. The functional role of the cortico-olivocochlear efferent system remains debated. We hypothesized that auditory cortex basal activity modulates cochlear and auditory-nerve afferent responses through the efferent system. Methodology/Principal Findings Cochlear microphonics (CM), auditory-nerve compound action potentials (CAP) and auditory cortex evoked potentials (ACEP) were recorded in twenty anesthetized chinchillas, before, during and after auditory cortex deactivation by two methods: lidocaine microinjections or cortical cooling with cryoloops. Auditory cortex deactivation induced a transient reduction in ACEP amplitudes in fifteen animals (deactivation experiments) and a permanent reduction in five chinchillas (lesion experiments). We found significant changes in the amplitude of CM in both types of experiments, being the most common effect a CM decrease found in fifteen animals. Concomitantly to CM amplitude changes, we found CAP increases in seven chinchillas and CAP reductions in thirteen animals. Although ACEP amplitudes were completely recovered after ninety minutes in deactivation experiments, only partial recovery was observed in the magnitudes of cochlear responses. Conclusions/Significance These results show that blocking ongoing auditory cortex activity modulates CM and CAP responses, demonstrating that cortico-olivocochlear circuits regulate auditory nerve and cochlear responses through a basal efferent tone. The diversity of the obtained effects suggests that there are at least two functional pathways from the auditory cortex to the cochlea. PMID:22558383

Activation of the canonical nuclear factor-κB pathway is involved in isoflurane-induced hippocampal interleukin-1β elevation and the resultant cognitive deficits in aged rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zheng-Qian; Rong, Xiao-Ying; Liu, Ya-Jie

Highlights: •Isoflurane induces hippocampal IL-1β elevation and cognitive deficits in aged rats. •Isoflurane transiently activates the canonical NF-κB pathway in aged rat hippocampus. •NF-κB inhibitor mitigates isoflurane-induced IL-1β elevation and cognitive deficits. •We report a linkage between NF-κB signaling, IL-1β expression, and cognitive changes. -- Abstract: Although much recent evidence has demonstrated that neuroinflammation contributes to volatile anesthetic-induced cognitive deficits, there are few existing mechanistic explanations for this inflammatory process. This study was conducted to investigate the effects of the volatile anesthetic isoflurane on canonical nuclear factor (NF)-κB signaling, and to explore its association with hippocampal interleukin (IL)-1β levels andmore » anesthetic-related cognitive changes in aged rats. After a 4-h exposure to 1.5% isoflurane in 20-month-old rats, increases in IκB kinase and IκB phosphorylation, as well as a reduction in the NF-κB inhibitory protein (IκBα), were observed in the hippocampi of isoflurane-exposed rats compared with control rats. These events were accompanied by an increase in NF-κB p65 nuclear translocation at 6 h after isoflurane exposure and hippocampal IL-1β elevation from 1 to 6 h after isoflurane exposure. Nevertheless, no significant neuroglia activation was observed. Pharmacological inhibition of NF-κB activation by pyrrolidine dithiocarbamate markedly suppressed the IL-1β increase and NF-κB signaling, and also mitigated the severity of cognitive deficits in the Morris water maze task. Overall, our results demonstrate that isoflurane-induced cognitive deficits may stem from upregulation of hippocampal IL-1β, partially via activation of the canonical NF-κB pathway, in aged rats.« less

Essential Role of Cofilin-1 in Regulating Thrombin-induced RelA/p65 Nuclear Translocation and Intercellular Adhesion Molecule 1 (ICAM-1) Expression in Endothelial Cells*

PubMed Central

Fazal, Fabeha; Bijli, Kaiser M.; Minhajuddin, Mohd; Rein, Theo; Finkelstein, Jacob N.; Rahman, Arshad

2009-01-01

Activation of RhoA/Rho-associated kinase (ROCK) pathway and the associated changes in actin cytoskeleton induced by thrombin are crucial for activation of NF-κB and expression of its target gene ICAM-1 in endothelial cells. However, the events acting downstream of RhoA/ROCK to mediate these responses remain unclear. Here, we show a central role of cofilin-1, an actin-binding protein that promotes actin depolymerization, in linking RhoA/ROCK pathway to dynamic alterations in actin cytoskeleton that are necessary for activation of NF-κB and thereby expression of ICAM-1 in these cells. Stimulation of human umbilical vein endothelial cells with thrombin resulted in Ser3 phosphorylation/inactivation of cofilin and formation of actin stress fibers in a ROCK-dependent manner. RNA interference knockdown of cofilin-1 stabilized the actin filaments and inhibited thrombin- and RhoA-induced NF-κB activity. Similarly, constitutively inactive mutant of cofilin-1 (Cof1-S3D), known to stabilize the actin cytoskeleton, inhibited NF-κB activity by thrombin. Overexpression of wild type cofilin-1 or constitutively active cofilin-1 mutant (Cof1-S3A), known to destabilize the actin cytoskeleton, also impaired thrombin-induced NF-κB activity. Additionally, depletion of cofilin-1 was associated with a marked reduction in ICAM-1 expression induced by thrombin. The effect of cofilin-1 depletion on NF-κB activity and ICAM-1 expression occurred downstream of IκBα degradation and was a result of impaired RelA/p65 nuclear translocation and consequently, RelA/p65 binding to DNA. Together, these data show that cofilin-1 occupies a central position in RhoA-actin pathway mediating nuclear translocation of RelA/p65 and expression of ICAM-1 in endothelial cells. PMID:19483084

Essential role of cofilin-1 in regulating thrombin-induced RelA/p65 nuclear translocation and intercellular adhesion molecule 1 (ICAM-1) expression in endothelial cells.

PubMed

Fazal, Fabeha; Bijli, Kaiser M; Minhajuddin, Mohd; Rein, Theo; Finkelstein, Jacob N; Rahman, Arshad

2009-07-31

Activation of RhoA/Rho-associated kinase (ROCK) pathway and the associated changes in actin cytoskeleton induced by thrombin are crucial for activation of NF-kappaB and expression of its target gene ICAM-1 in endothelial cells. However, the events acting downstream of RhoA/ROCK to mediate these responses remain unclear. Here, we show a central role of cofilin-1, an actin-binding protein that promotes actin depolymerization, in linking RhoA/ROCK pathway to dynamic alterations in actin cytoskeleton that are necessary for activation of NF-kappaB and thereby expression of ICAM-1 in these cells. Stimulation of human umbilical vein endothelial cells with thrombin resulted in Ser(3) phosphorylation/inactivation of cofilin and formation of actin stress fibers in a ROCK-dependent manner. RNA interference knockdown of cofilin-1 stabilized the actin filaments and inhibited thrombin- and RhoA-induced NF-kappaB activity. Similarly, constitutively inactive mutant of cofilin-1 (Cof1-S3D), known to stabilize the actin cytoskeleton, inhibited NF-kappaB activity by thrombin. Overexpression of wild type cofilin-1 or constitutively active cofilin-1 mutant (Cof1-S3A), known to destabilize the actin cytoskeleton, also impaired thrombin-induced NF-kappaB activity. Additionally, depletion of cofilin-1 was associated with a marked reduction in ICAM-1 expression induced by thrombin. The effect of cofilin-1 depletion on NF-kappaB activity and ICAM-1 expression occurred downstream of IkappaBalpha degradation and was a result of impaired RelA/p65 nuclear translocation and consequently, RelA/p65 binding to DNA. Together, these data show that cofilin-1 occupies a central position in RhoA-actin pathway mediating nuclear translocation of RelA/p65 and expression of ICAM-1 in endothelial cells.

Protective Role of Taurine against Arsenic-Induced Mitochondria-Dependent Hepatic Apoptosis via the Inhibition of PKCδ-JNK Pathway

PubMed Central

Das, Joydeep; Ghosh, Jyotirmoy; Manna, Prasenjit; Sil, Parames C.

2010-01-01

Background Oxidative stress-mediated hepatotoxic effect of arsenic (As) is mainly due to the depletion of glutathione (GSH) in liver. Taurine, on the other hand, enhances intracellular production of GSH. Little is known about the mechanism of the beneficial role of taurine in As-induced hepatic pathophysiology. Therefore, in the present study we investigated its beneficial role in As-induced hepatic cell death via mitochondria-mediated pathway. Methodology/Principal Findings Rats were exposed to NaAsO2 (2 mg/kg body weight for 6 months) and the hepatic tissue was used for oxidative stress measurements. In addition, the pathophysiologic effect of NaAsO2 (10 µM) on hepatocytes was evaluated by determining cell viability, mitochondrial membrane potential and ROS generation. As caused mitochondrial injury by increased oxidative stress and reciprocal regulation of Bcl-2, Bcl-xL/Bad, Bax, Bim in association with increased level of Apaf-1, activation of caspase 9/3, cleavage of PARP protein and ultimately led to apoptotic cell death. In addition, As markedly increased JNK and p38 phosphorylation with minimal disturbance of ERK. Pre-exposure of hepatocytes to a JNK inhibitor SP600125 prevented As-induced caspase-3 activation, ROS production and loss in cell viability. Pre-exposure of hepatocytes to a p38 inhibitor SB2035, on the other hand, had practically no effect on these events. Besides, As activated PKCδ and pre-treatment of hepatocytes with its inhibitor, rottlerin, suppressed the activation of JNK indicating that PKCδ is involved in As-induced JNK activation and mitochondrial dependent apoptosis. Oral administration of taurine (50 mg/kg body weight for 2 weeks) both pre and post to NaAsO2 exposure or incubation of the hepatocytes with taurine (25 mM) were found to be effective in counteracting As-induced oxidative stress and apoptosis. Conclusions/Significance Results indicate that taurine treatment improved As-induced hepatic damages by inhibiting PKCδ-JNK signalling pathways. Therefore taurine supplementation could provide a new approach for the reduction of hepatic complication due to arsenic poisoning. PMID:20830294

Genetic inhibition of protein kinase Cε attenuates necrosis in experimental pancreatitis

PubMed Central

Liu, Yannan; Tan, Tanya; Jia, Wenzhuo; Lugea, Aurelia; Mareninova, Olga; Waldron, Richard T.; Pandol, Stephen J.

2014-01-01

Understanding the regulation of death pathways, necrosis and apoptosis, in pancreatitis is important for developing therapies directed to the molecular pathogenesis of the disease. Protein kinase Cε (PKCε) has been previously shown to regulate inflammatory responses and zymogen activation in pancreatitis. Furthermore, we demonstrated that ethanol specifically activated PKCε in pancreatic acinar cells and that PKCε mediated the sensitizing effects of ethanol on inflammatory response in pancreatitis. Here we investigated the role of PKCε in the regulation of death pathways in pancreatitis. We found that genetic deletion of PKCε resulted in decreased necrosis and severity in the in vivo cerulein-induced pancreatitis and that inhibition of PKCε protected the acinar cells from CCK-8 hyperstimulation-induced necrosis and ATP reduction. These findings were associated with upregulation of mitochondrial Bak and Bcl-2/Bcl-xL, proapoptotic and prosurvival members in the Bcl-2 family, respectively, as well as increased mitochondrial cytochrome c release, caspase activation, and apoptosis in pancreatitis in PKCε knockout mice. We further confirmed that cerulein pancreatitis induced a dramatic mitochondrial translocation of PKCε, suggesting that PKCε regulated necrosis in pancreatitis via mechanisms involving mitochondria. Finally, we showed that PKCε deletion downregulated inhibitors of apoptosis proteins, c-IAP2, survivin, and c-FLIPs while promoting cleavage/inactivation of receptor-interacting protein kinase (RIP). Taken together, our findings provide evidence that PKCε activation during pancreatitis promotes necrosis through mechanisms involving mitochondrial proapoptotic and prosurvival Bcl-2 family proteins and upregulation of nonmitochondrial pathways that inhibit caspase activation and RIP cleavage/inactivation. Thus PKCε is a potential target for prevention and/or treatment of acute pancreatitis. PMID:25035113

Reversal of muscle atrophy by Zhimu and Huangbai herb pair via activation of IGF-1/Akt and autophagy signal in cancer cachexia.

PubMed

Zhuang, Pengwei; Zhang, Jinbao; Wang, Yan; Zhang, Mixia; Song, Lili; Lu, Zhiqiang; Zhang, Lu; Zhang, Fengqi; Wang, Jing; Zhang, Yanjun; Wei, Hongjun; Li, Hongyan

2016-03-01

Muscle atrophy is the prominent clinical feature of cancer-induced cachexia. Zhimu and Huangbai herb pair (ZBHP) has been used since ancient China times and have been phytochemically investigated for constituents that might cause anti-cancer, diabetes, and their complication. In this study, the effects and mechanisms of ZBHP on reversal of muscle atrophy were explored. C57BL/6 mice implanted with colon-26 adenocarcinoma were chosen to develop cancer cachexia for evaluating the effects of ZBHP on reversal of muscle atrophy. The body weight, survival time, inflammatory cytokines, and pathological changes of muscle were monitored. In addition, IGF-1/Akt and autophagy pathway members were analyzed to interpret the mechanism of drug response. The function and morphology of skeletal muscle in cachexia model were significantly disturbed, and the survival time was shortened. Consistently, inflammatory cytokines and muscle atrophy-related atrogin-1, MuRF1, and FOXO3 were significantly increased, and IGF-1/Akt and autophagy signal pathways were depressed. Treatment with ZBHP significantly alleviated tumor-free body weight reduction and cachexia-induced changes in cytokines and prolonged survival. ZBHP treatment not only inhibited the muscle atrophy-related genes but also activated the IGF-1/Akt and autophagy signal pathways to facilitate the protein synthesis. The results revealed that ZBHP treatment could inhibit the muscle atrophy induced by cancer cachexia and prolong the survival time, and ZBHP may be of value as a pharmacological alternative in treatment of cancer cachexia.

CG200745, an HDAC inhibitor, induces anti-tumour effects in cholangiocarcinoma cell lines via miRNAs targeting the Hippo pathway.

PubMed

Jung, Dawoon E; Park, Soo Been; Kim, Kahee; Kim, Chanyang; Song, Si Young

2017-09-07

Cholangiocarcinoma is a devastating malignancy with fatal complications that exhibits low response and resistance to chemotherapy. Here, we evaluated the anticancer effects of CG200745, a novel histone deacetylase inhibitor, either alone or in combination with standard chemotherapy drugs in cholangiocarcinoma cells. CG200745 dose-dependently reduced the viability of cholangiocarcinoma cells in vitro and decreased tumour volume and weight in a xenograft model. Administering CG200745 along with other chemotherapeutic agents including gemcitabine, 5-fluorouracil (5-FU), cisplatin, oxaliplatin, or gemcitabine plus cisplatin further decreased cholangiocarcinoma cell viability, with a combination index < 1 that indicated synergistic action. CG200745 also enhanced the sensitivity of gemcitabine-resistant cells to gemcitabine and 5-FU, thereby decreasing cell viability and inducing apoptosis. This was accompanied by downregulation of YAP, TEAD4, TGF-β2, SMAD3, NOTCH3, HES5, Axl, and Gas6 and upregulation of the miRNAs miR-22-3p, miR-22-5p, miR-194-5p, miR-194-3p, miR-194-5p, miR-210-3p, and miR-509-3p. The Ingenuity Pathway Analysis revealed that CG200745 mainly targets the Hippo signalling pathway by inducing miR-509-3p expression. Thus, CG200745 inhibits cholangiocarcinoma growth in vitro and in vivo, and acts synergistically when administered in combination with standard chemotherapeutic agents, enabling dose reduction. CG200745 is therefore expected to improve the outcome of cholangiocarcinoma patients who exhibit resistance to conventional therapies.

The Role of Na+/K+-ATPase during Chick Skeletal Myogenesis

PubMed Central

Oliveira, Taissa Neustadt; Possidonio, Ana Claudia; Soares, Carolina Pontes; Ayres, Rodrigo; Costa, Manoel Luis; Quintas, Luis Eduardo Menezes; Mermelstein, Cláudia

2015-01-01

The formation of a vertebrate skeletal muscle fiber involves a series of sequential and interdependent events that occurs during embryogenesis. One of these events is myoblast fusion which has been widely studied, yet not completely understood. It was previously shown that during myoblast fusion there is an increase in the expression of Na+/K+-ATPase. This fact prompted us to search for a role of the enzyme during chick in vitro skeletal myogenesis. Chick myogenic cells were treated with the Na+/K+-ATPase inhibitor ouabain in four different concentrations (0.01-10 μM) and analyzed. Our results show that 0.01, 0.1 and 1 μM ouabain did not induce changes in cell viability, whereas 10 μM induced a 45% decrease. We also observed a reduction in the number and thickness of multinucleated myotubes and a decrease in the number of myoblasts after 10 μM ouabain treatment. We tested the involvement of MEK-ERK and p38 signaling pathways in the ouabain-induced effects during myogenesis, since both pathways have been associated with Na+/K+-ATPase. The MEK-ERK inhibitor U0126 alone did not alter cell viability and did not change ouabain effect. The p38 inhibitor SB202190 alone or together with 10 μM ouabain did not alter cell viability. Our results show that the 10 μM ouabain effects in myofiber formation do not involve the MEK-ERK or the p38 signaling pathways, and therefore are probably related to the pump activity function of the Na+/K+-ATPase. PMID:25775465

The role of Na+/K+-ATPase during chick skeletal myogenesis.

PubMed

Oliveira, Taissa Neustadt; Possidonio, Ana Claudia; Soares, Carolina Pontes; Ayres, Rodrigo; Costa, Manoel Luis; Quintas, Luis Eduardo Menezes; Mermelstein, Cláudia

2015-01-01

The formation of a vertebrate skeletal muscle fiber involves a series of sequential and interdependent events that occurs during embryogenesis. One of these events is myoblast fusion which has been widely studied, yet not completely understood. It was previously shown that during myoblast fusion there is an increase in the expression of Na+/K+-ATPase. This fact prompted us to search for a role of the enzyme during chick in vitro skeletal myogenesis. Chick myogenic cells were treated with the Na+/K+-ATPase inhibitor ouabain in four different concentrations (0.01-10 μM) and analyzed. Our results show that 0.01, 0.1 and 1 μM ouabain did not induce changes in cell viability, whereas 10 μM induced a 45% decrease. We also observed a reduction in the number and thickness of multinucleated myotubes and a decrease in the number of myoblasts after 10 μM ouabain treatment. We tested the involvement of MEK-ERK and p38 signaling pathways in the ouabain-induced effects during myogenesis, since both pathways have been associated with Na+/K+-ATPase. The MEK-ERK inhibitor U0126 alone did not alter cell viability and did not change ouabain effect. The p38 inhibitor SB202190 alone or together with 10 μM ouabain did not alter cell viability. Our results show that the 10 μM ouabain effects in myofiber formation do not involve the MEK-ERK or the p38 signaling pathways, and therefore are probably related to the pump activity function of the Na+/K+-ATPase.

Solar-simulated radiation and heat treatment induced metalloproteinase-1 expression in cultured dermal fibroblasts via distinct pathways: implications on reduction of sun-associated aging.

PubMed

Lan, Cheng-Che E; Wu, Ching-Shang; Yu, Hsin-Su

2013-12-01

Sun exposure is an important environmental factor affecting human beings. Most knowledge regarding solar aging focused on light radiation (photoaging), and little emphasis has been placed on heat, a factor that is also closely associated with sun exposure. This study was launched to evaluate the effects of simulated solar radiation (SSR) and environmental heat on skin fibroblasts in terms of dermal aging. Cultured human dermal fibroblasts were treated with moderate amount of SSR (200J/cm(2)) and heat (+2°C). The metalloproteinase-1 (MMP-1) expression was used as a surrogate marker for dermal aging and the involved regulatory mechanisms were explored. Both treatment conditions did not affect viability but significantly increased the expressions of MMP-1. In parallel, both treatments increased the intracellular levels of reactive oxygen species (ROS), but the increase induced by SSR is much greater than heat. In contrast, transient receptor potential vanilloid 1 (TRPV-1), the sensor of environmental heat, was upregulated by heat but not SSR treatment. Pretreating fibroblasts with antioxidant abrogated the SSR-induced MMP-1 but has limited effect on heat-induced MMP-1. On the other hand, TRPV-1 antagonist pretreatment reduced heat-induced MMP-1 in fibroblasts but not their SSR-treated counterparts. Both SSR and heat induced MMP-1 expression in dermal fibroblasts but through different pathways. As current strategies for reducing sun-related aging focused on filtering of light and use of antioxidants, future strategies design to reduce solar aging should also incorporate heat-induced aging into consideration. Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

The role of S1PR2 in bile acid-induced cholangiocyte proliferation and cholestasis-induced liver injury in mice

PubMed Central

Wang, Yongqing; Aoki, Hiroaki; Yang, Jing; Peng, Kesong; Liu, Runping; Li, Xiaojiaoyang; Qiang, Xiaoyan; Sun, Lixin; Gurley, Emily C; Lai, Guanhua; Zhang, Luyong; Liang, Guang; Nagahashi, Masayuki; Takabe, Kazuaki; Pandak, William M; Hylemon, Phillip B.; Zhou, Huiping

2017-01-01

Bile duct obstruction is a potent stimulus for cholangiocyte proliferation, especially for large cholangiocytes. Our previous studies reported that conjugated bile acids (CBAs) activate the AKT and ERK1/2 signaling pathways via the sphingosine 1-phosphate receptor 2 (S1PR2) in hepatocytes and cholangiocarcinoma cells. It also has been reported that taurocholate (TCA) promotes large cholangiocyte proliferation and protects cholangiocytes from bile duct ligation (BDL)-induced apoptosis. However, the role of S1PR2 in bile acid-mediated cholangiocyte proliferation and cholestatic liver injury has not been elucidated. Here we report that S1PR2 is the predominant S1PR expressed in cholangiocytes. Both TCA- and S1P-induced activation of ERK1/2 and AKT were inhibited by JTE-013, a specific antagonist of S1PR2, in cholangiocytes. In addition, TCA- and S1P-induced cell proliferation and migration were inhibited by JTE-013 and a specific shRNA of S1PR2 as well as chemical inhibitors of ERK1/2 and AKT in mouse cholangiocytes. In BDL mice, the expression of S1PR2 was upregulated in whole liver and cholangiocytes. S1PR2 deficiency significantly reduced BDL-induced cholangiocyte proliferation and cholestatic injury as indicated by significant reduction of inflammation and liver fibrosis in S1PR2−/− mice. Treatment of BDL mice with JTE-013 significantly reduced total bile acid levels in the serum and cholestatic liver injury. This study suggests that the CBA-induced activation of S1PR2-mediated signaling pathways plays a critical role in obstructive cholestasis and may represent a novel therapeutic target for cholestatic liver diseases. PMID:28120434

IGF-1 prevents ANG II-induced skeletal muscle atrophy via Akt- and Foxo-dependent inhibition of the ubiquitin ligase atrogin-1 expression

PubMed Central

Yoshida, Tadashi; Semprun-Prieto, Laura; Sukhanov, Sergiy

2010-01-01

Congestive heart failure is associated with activation of the renin-angiotensin system and skeletal muscle wasting. Angiotensin II (ANG II) has been shown to increase muscle proteolysis and decrease circulating and skeletal muscle IGF-1. We have shown previously that skeletal muscle-specific overexpression of IGF-1 prevents proteolysis and apoptosis induced by ANG II. These findings indicated that downregulation of IGF-1 signaling in skeletal muscle played an important role in the wasting effect of ANG II. However, the signaling pathways and mechanisms whereby IGF-1 prevents ANG II-induced skeletal muscle atrophy are unknown. Here we show ANG II-induced transcriptional regulation of two ubiquitin ligases atrogin-1 and muscle ring finger-1 (MuRF-1) that precedes the reduction of skeletal muscle IGF-1 expression, suggesting that activation of atrogin-1 and MuRF-1 is an initial mechanism leading to skeletal muscle atrophy in response to ANG II. IGF-1 overexpression in skeletal muscle prevented ANG II-induced skeletal muscle wasting and the expression of atrogin-1, but not MuRF-1. Dominant-negative Akt and constitutively active Foxo-1 blocked the ability of IGF-1 to prevent ANG II-mediated upregulation of atrogin-1 and skeletal muscle wasting. Our findings demonstrate that the ability of IGF-1 to prevent ANG II-induced skeletal muscle wasting is mediated via an Akt- and Foxo-1-dependent signaling pathway that results in inhibition of atrogin-1 but not MuRF-1 expression. These data suggest strongly that atrogin-1 plays a critical role in mechanisms of ANG II-induced wasting in vivo. PMID:20228261

Carbenoxolone prevents chemical eye ischemia-reperfusion-induced cell death via 11β-hydroxysteroid dehydrogenase type 1 inhibition.

PubMed

Choi, Kyoung-Jin; Na, Yoon-Ju; Park, Sung Bum; Jung, Won Hoon; Sung, Hye-Rim; Kim, Ki Young

2017-09-01

Glaucoma is one of the leading causes of preventable blindness diseases, affecting more than 2 million people in the United States. Recently, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors were found to exert preventive effects against glaucoma. Therefore, we investigated whether carbenoxolone (CBX), an 11β-HSD1 inhibitor, prevents chemical ischemia-reperfusion-induced cell death in human trabecular meshwork (HTM) cells. The present study demonstrated that CBX inhibited cell death caused by iodoacetic acid (IAA)-induced ischemia-reperfusion, and its effect was associated with the inhibition of 11β-HSD1 expression and activity. Furthermore, CBX reversed the IAA-induced structural damage on filamentous actin in HTM cells. In IAA-treated cells, the levels of 11β-HSD1 and the apoptosis-related factors Bax and FASL were increased throughout the reperfusion period, and CBX was able to attenuate the expression of 11β-HSD1 and the apoptosis-related factors. CBX also effectively suppressed IAA-induced intracellular ROS formation and cytochrome c release, which are involved in the mitochondrial apoptosis pathway. In addition, IAA-induced chemical ischemia-reperfusion stimulated TNF-α expression and NF-κB p65 phosphorylation, and these effects were attenuated by CBX. 11β-HSD1 RNAi also suppressed IAA-induced cell apoptosis via reduction of oxidative stress and inhibition of the pro-inflammatory pathway. Taken together, the present study demonstrated that the inhibition of 11β-HSD1 protected the TM against chemical ischemia-reperfusion injury, suggesting that the use of 11β-HSD1 inhibitors could be a useful strategy for glaucoma therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogen sulfide ameliorated L-NAME-induced hypertensive heart disease by the Akt/eNOS/NO pathway.

PubMed

Jin, Sheng; Teng, Xu; Xiao, Lin; Xue, Hongmei; Guo, Qi; Duan, Xiaocui; Chen, Yuhong; Wu, Yuming

2017-12-01

Reductions in hydrogen sulfide (H 2 S) production have been implicated in the pathogenesis of hypertension; however, no studies have examined the functional role of hydrogen sulfide in hypertensive heart disease. We hypothesized that the endogenous production of hydrogen sulfide would be reduced and exogenous hydrogen sulfide would ameliorate cardiac dysfunction in N ω -nitro- L-arginine methyl ester ( L-NAME)-induced hypertensive rats. Therefore, this study investigated the cardioprotective effects of hydrogen sulfide on L-NAME-induced hypertensive heart disease and explored potential mechanisms. The rats were randomly divided into five groups: Control, Control + sodium hydrosulfide (NaHS), L-NAME, L-NAME + NaHS, and L-NAME + NaHS + glibenclamide (Gli) groups. Systolic blood pressure was monitored each week. In Langendorff-isolated rat heart, cardiac function represented by ±LV dP/dt max and left ventricular developing pressure was recorded after five weeks of treatment. Hematoxylin and Eosin and Masson's trichrome staining and myocardium ultrastructure under transmission electron microscopy were used to evaluate cardiac remodeling. The plasma nitric oxide and hydrogen sulfide concentrations, as well as nitric oxide synthases and cystathionine-γ-lyase activity in left ventricle tissue were determined. The protein expression of p-Akt, Akt, p-eNOS, and eNOS in left ventricle tissue was analyzed using Western blot. After five weeks of L-NAME treatment, there was a time-dependent hypertension, cardiac remodeling, and dysfunction accompanied by a decrease in eNOS phosphorylation, nitric oxide synthase activity, and nitric oxide concentration. Meanwhile, cystathionine-γ-lyase activity and hydrogen sulfide concentration were also decreased. NaHS treatment significantly increased plasma hydrogen sulfide concentration and subsequently promoted the Akt/eNOS/NO pathway which inhibited the development of hypertension and attenuated cardiac remodeling and dysfunction. The cardioprotective effects of NaHS were counteracted by Gli which inhibited the Akt/eNOS/NO pathway. This suggests that the effects of hydrogen sulfide were mediated by the activation of the K ATP channels. In conclusion, hydrogen sulfide ameliorated L-NAME-induced hypertensive heart disease via the activation of the Akt/eNOS/NO pathway, which was mediated by K ATP channels. Impact statement 1. We found that H 2 S ameliorated L-NAME-induced cardiac remodeling and dysfunction, and played a protective role in L-NAME-induced hypertensive heart disease, which the existing studies have not reported. 2. H 2 S activated the Akt/eNOS/NO pathway, thereby playing a cardioprotective role in L-NAME-induced hypertensive heart disease. 3. The cardioprotective effect of H 2 S was mediated by ATP-sensitive potassium channels.

Hypoxia increases transepithelial electrical conductance and reduces occludin at the plasma membrane in alveolar epithelial cells via PKC-ζ and PP2A pathway

PubMed Central

Caraballo, Juan Carlos; Yshii, Cecilia; Butti, Maria L.; Westphal, Whitney; Borcherding, Jennifer A.; Allamargot, Chantal

2011-01-01

During pulmonary edema, the alveolar space is exposed to a hypoxic environment. The integrity of the alveolar epithelial barrier is required for the reabsorption of alveolar fluid. Tight junctions (TJ) maintain the integrity of this barrier. We set out to determine whether hypoxia creates a dysfunctional alveolar epithelial barrier, evidenced by an increase in transepithelial electrical conductance (Gt), due to a decrease in the abundance of TJ proteins at the plasma membrane. Alveolar epithelial cells (AEC) exposed to mild hypoxia (Po2 = 50 mmHg) for 30 and 60 min decreased occludin abundance at the plasma membrane and significantly increased Gt. Other cell adhesion molecules such as E-cadherin and claudins were not affected by hypoxia. AEC exposed to hypoxia increased superoxide, but not hydrogen peroxide (H2O2). Overexpression of superoxide dismutase 1 (SOD1) but not SOD2 prevented the hypoxia-induced Gt increase and occludin reduction in AEC. Also, overexpression of catalase had a similar effect as SOD1, despite not detecting any increase in H2O2 during hypoxia. Blocking PKC-ζ and protein phosphatase 2A (PP2A) prevented the hypoxia-induced occludin reduction at the plasma membrane and increase in Gt. In summary, we show that superoxide, PKC-ζ, and PP2A are involved in the hypoxia-induced increase in Gt and occludin reduction at the plasma membrane in AEC. PMID:21257729

Fermentable metabolite of Zymomonas mobilis controls collagen reduction in photoaging skin by improving TGF-beta/Smad signaling suppression.

PubMed

Tanaka, Hiroshi; Yamaba, Hiroyuki; Kosugi, Nobuhiko; Mizutani, Hiroshi; Nakata, Satoru

2008-04-01

Solar ultraviolet (UV) irradiation causes damages on human skin and premature skin aging (photoaging). UV-induced reduction of type I collagen in dermis is widely considered primarily induction of wrinkled appearance of photoaging skin. Type I procollagen synthesis is reduced under UV irradiation by blocking transforming growth factor-beta (TGF-beta)/Smad signaling; more specifically, it is down-regulation of TGF-beta type II receptor (T beta RII). Therefore, preventing UV-induced loss of T beta RII results decreased type I collagen reduction in photoaging skin. Zymomonas mobilis is an alcohol fermentable, gram-negative facultative anaerobic bacterium whose effect on skin tissue is scarcely studied. We investigated the protective effects of fermentable metabolite of Z. mobilis (FM of Z. mobilis) against reduction of type I procollagen synthesis of UV-induced down-regulation of T beta RII in human dermal fibroblasts FM of Z. mobilis was obtained from lyophilization of bacterium culture supernatant. The levels of T beta RII and type I procollagen mRNA in human dermal fibroblasts were measured by quantitative real-time RT-PCR, and T beta RII protein levels were assayed by western blotting. T beta RII, type I procollagen, and type I collagen proteins in human dermal fibroblasts or hairless mouse skin were detected by immunostaining. FM of Z. mobilis inhibited down regulation of T beta RII mRNA, and protein levels in UVB irradiated human dermal fibroblasts consequently recover reduced type I procollagen synthesis. These results indicate UVB irradiation inhibits type I procollagen synthesis by suppression of TGF-beta/Smad signaling pathway, and FM of Z. mobilis has inhibitory effect on UVB-induced reduction of type I procollagen synthesis. While short period UVB irradiation decreased both T beta RII and type I procollagen protein levels in hairless mouse skin, topical application of FM of Z. mobilis prevented this decrease. Wrinkle formation in hairless mouse skin surface was accelerated by continuous 5 month UVB irradiation along with a reduction of type I collagen in the dermis, but this change was prevented by topical application of FM of Z. mobilis. From this experimental data, it is suggested that FM of Z. mobilis is effective for suppression of wrinkle formation in photoaging skin by inhibition of type I procollagen synthesis reduction.

Apigenin induces apoptosis in human leukemia cells and exhibits anti-leukemic activity in vivo via inactivation of Akt and activation of JNK

PubMed Central

Budhraja, Amit; Gao, Ning; Zhang, Zhuo; Son, Young-Ok; Cheng, Senping; Wang, Xin; Ding, Songze; Hitron, Andrew; Chen, Gang; Luo, Jia; Shi, Xianglin

2015-01-01

In this study, we investigated the functional role of Akt and JNK signaling cascades in apigenin-induced apoptosis in U937 human leukemia cells and anti-leukemic activity of apigenin in vivo. Apigenin-induced apoptosis by inactivation of Akt with a concomitant activation of JNK, Mcl-1 and Bcl-2 down-regulation, cytochrome c release from mitochondria and activation of caspases. Constitutively active myristolated Akt prevented apigenin-induced JNK, caspases activation, and apoptosis. Conversely, LY294002 and a dominant negative construct of Akt potentiated apigenin-induced apoptosis in leukemia cells. Interruption of JNK pathway showed marked reduction in apigenin-induced caspases activation and apoptosis in leukemia cells. Furthermore, in vivo administration of apigenin resulted in attenuation of tumor growth in U937 xenografts accompanied inactivation of Akt and activation of JNK. Attenuation of tumor growth in U937 xenografts by apigenin raises the possibility that apigenin may have clinical implications and can be further tested for incorporating in leukemia treatment regimens. PMID:22084167

Regulation of ROS in transmissible gastroenteritis virus-activated apoptotic signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Li; College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158; Zhao, Xiaomin

Highlights: •TGEV infection induced ROS accumulation. •ROS accumulation is involved in TGEV-induced mitochondrial integrity impairment. •ROS is associated with p53 activation and apoptosis occurrence in TGEV-infected cells. -- Abstract: Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, causes severe lethal watery diarrhea and dehydration in piglets. Previous studies indicate that TGEV infection induces cell apoptosis in host cells. In this study, we investigated the roles and regulation of reactive oxygen species (ROS) in TGEV-activated apoptotic signaling. The results showed that TGEV infection induced ROS accumulation, whereas UV-irradiated TGEV did not promote ROS accumulation. In addition, TGEV infection lowered mitochondrial transmembrane potentialmore » in PK-15 cell line, which could be inhibited by ROS scavengers, pyrrolidinedithiocarbamic (PDTC) and N-acetyl-L-cysteine (NAC). Furthermore, the two scavengers significantly inhibited the activation of p38 MAPK and p53 and further blocked apoptosis occurrence through suppressing the TGEV-induced Bcl-2 reduction, Bax redistribution, cytochrome c release and caspase-3 activation. These results suggest that oxidative stress pathway might be a key element in TGEV-induced apoptosis and TGEV pathogenesis.« less

Impact of Next Generation District Heating Systems on Distribution Network Heat Losses: A Case Study Approach

NASA Astrophysics Data System (ADS)

Li, Yu; Rezgui, Yacine

2018-01-01

District heating (DH) is a promising energy pathway to alleviate environmental negative impacts induced by fossil fuels. Improving the performance of DH systems is one of the major challenges facing its wide adoption. This paper discusses the heat losses of the next generation DH based on the constructed Simulink model. Results show that lower distribution temperature and advanced insulation technology greatly reduce network heat losses. Also, the network heat loss can be further minimized by a reduction of heat demand in buildings.

Effect of dehydration on thirst and drinking during immersion in men

NASA Technical Reports Server (NTRS)

Sagawa, S.; Miki, K.; Tajima, F.; Tanaka, H.; Choi, J. K.; Keil, L. C.; Shiraki, K.; Greenleaf, J. E.

1992-01-01

The effect of water immersion on voluntary water intake, subjective evaluations of thirst and gastrointestinal state, and associated fluid-electrolyte and hormonal interaction were investigated. Eight men (19-25 yrs of age) were immersed to the neck while sitting for three hours at 34.5 C or in air at 28 C when euhydrated and hypohydrated by 3.6 percent body weight loss. Within the first ten minutes of immersion the significant reduction in drinking in the hypo-H2O experiment was associated with unchanged plasma Na(+), plasma osmolality, heart rates, and mean arterial pressures. Different responses increased cardiac output, plasma volume, and atrial natriuretic peptides and decreased plasma renin activity and arginine vasopressin. It is concluded that the extracellular pathway, as opposed to the osmotic pathway, appears to be the major mechanism for immersion-induced suppression of drinking.

Coupling molecular catalysts with nanostructured surfaces for efficient solar fuel production

NASA Astrophysics Data System (ADS)

Jin, Tong

Solar fuel generation via carbon dioxide (CO2) reduction is a promising approach to meet the increasing global demand for energy and to minimize the impact of energy consumption on climate change. However, CO2 is thermodynamically stable; its activation often requires the use of appropriate catalysts. In particular, molecular catalysts with well-defined structures and tunability have shown excellent activity in photochemical CO2 reduction. These homogenous catalysts, however, suffer from poor stability under photochemical conditions and difficulty in recycling from the reaction media. Heterogenized molecular catalysts, particularly those prepared by coupling molecular catalysts with solid-state surfaces, have attracted more attention in recent years as potential solutions to address the issues associated with molecular catalysts. In this work, solar CO2 reduction is investigated using systems coupling molecular catalysts with robust nanostructured surfaces. In Chapter 2, heterogenization of macrocyclic cobalt(III) and nickel (II) complexes on mesoporous silica surface was achieved by different methods. Direct ligand derivatization significantly lowered the catalytic activity of Co(III) complex, while grafting the Co(III) complex onto silica surface through Si-O-Co linkage resulted in hybrid catalysts with excellent activity in CO2 reduction in the presence of p-terphenyl as a molecular photosensitizer. An interesting loading effect was observed, in which the optimal activity was achieved at a medium Co(III) surface density. Heterogenization of the Ni(II) complex on silica surface has also been implemented, the poor photocatalytic activity of the hybrid catalyst can be attributed to the intrinsic nature of the homogeneous analogue. This study highlighted the importance of appropriate linking strategies in preparing functional heterogenized molecular catalysts. Coupling molecular complexes with light-harvesting surfaces could avoid the use of expensive molecular photosensitizers. In Chapter 3, effective coupling of the macrocyclic Co(III) complex with titanium dioxide (TiO¬2) nanoparticles was achieved by two deposition methods. The synthesized hybrid photocatalysts were thoroughly characterized with a variety of techniques. Upon UV light irradiation, photoexcited electrons in TiO2 nanoparticles were transferred to the surface Co(III) catalyst for CO2 reduction. Production of carbon monoxide (CO) from CO2 was confirmed by isotope labeling combined with infrared spectroscopy. Deposition of the Co(III) catalyst through Ti-O-Co linkages was essential for the photo-induced electron transfer and CO2-reduction activity using the hybrid photocatalysts. In Chapter 4, molecular Re(I) and Co(II) catalysts were coupled with silicon-based photoelectrodes, including a silicon nanowire (SiNW) photoelectrode, to achieve photoelectrochemical CO2 reduction. Photovoltages between 300-600 mV were obtained using the molecular catalysts on the silicon photoelectrodes. SiNWs exhibited enhanced properties, including significantly higher photovoltages than a planar silicon photoelectrode, the ability to protect one of the molecular catalysts from photo-induced decomposition, and excellent selectivity towards CO production in CO2 reduction. Recent theoretical and experimental work have demonstrated low-energy, binuclear pathways for CO2-to-CO conversion using several molecular catalysts. In such binuclear pathways, two metal centers work cooperatively to achieve two-electron CO2 reduction. Chapter 5 describes our effort to promote the binuclear pathway by grafting the molecular Co(III) catalyst onto silica surfaces. Different linking strategies were attempted to achieve this goal by planting the surface Co(III) sites in close proximity.

Activation of Wnt signaling pathway by human papillomavirus E6 and E7 oncogenes in HPV16-positive oropharyngeal squamous carcinoma cells.

PubMed

Rampias, Theodore; Boutati, Eleni; Pectasides, Eirini; Sasaki, Clarence; Kountourakis, Panteleimon; Weinberger, Paul; Psyrri, Amanda

2010-03-01

We sought to determine the role of human papillomavirus (HPV) E6 and E7 oncogenes in nuclear beta-catenin accumulation, a hallmark of activated canonical Wnt signaling pathway. We used HPV16-positive oropharyngeal cancer cell lines 147T and 090, HPV-negative cell line 040T, and cervical cell lines SiHa (bearing integrated HPV16) and HeLa (bearing integrated HPV18) to measure the cytoplasmic and nuclear beta-catenin levels and the beta-catenin/Tcf transcriptional activity before and after E6/E7 gene silencing. Repression of HPV E6 and E7 genes induced a substantial reduction in nuclear beta-catenin levels. Luciferase assay showed that transcriptional activation of Tcf promoter by beta-catenin was lower after silencing. The protein levels of beta-catenin are tightly regulated by the ubiquitin/proteasome system. We therefore performed expression analysis of regulators of beta-catenin degradation and nuclear transport and showed that seven in absentia homologue (Siah-1) mRNA and protein levels were substantially upregulated after E6/E7 repression. Siah-1 protein promotes the degradation of beta-catenin through the ubiquitin/proteasome system. To determine whether Siah-1 is important for the proteasomal degradation of beta-catenin in HPV16-positive oropharyngeal cancer cells, we introduced a Siah-1 expression vector into 147T and 090 cells and found substantial reduction of endogenous beta-catenin in these cells. Thus, E6 and E7 are involved in beta-catenin nuclear accumulation and activation of Wnt signaling in HPV-induced cancers. In addition, we show the significance of the endogenous Siah-1-dependent ubiquitin/proteasome pathway for beta-catenin degradation and its regulation by E6/E7 viral oncoproteins in HPV16-positive oropharyngeal cancer cells.

Integrating both interaction pathways between warming and pesticide exposure on upper thermal tolerance in high- and low-latitude populations of an aquatic insect.

PubMed

Op de Beeck, Lin; Verheyen, Julie; Stoks, Robby

2017-05-01

Global warming and chemical pollution are key anthropogenic stressors with the potential to interact. While warming can change the impact of pollutants and pollutants can change the sensitivity to warming, both interaction pathways have never been integrated in a single experiment. Therefore, we tested the effects of warming and multiple pesticide pulses (allowing accumulation) of chlorpyrifos on upper thermal tolerance (CTmax) and associated physiological traits related to aerobic/anaerobic energy production in the damselfly Ischnura elegans. To also assess the role of latitude-specific thermal adaptation in shaping the impact of warming and pesticide exposure on thermal tolerance, we exposed larvae from replicated high- and low-latitude populations to the pesticide in a common garden rearing experiment at 20 and 24 °C, the mean summer water temperatures at high and low latitudes. As expected, exposure to chlorpyrifos resulted in a lower CTmax. Yet, this pesticide effect on CTmax was lower at 24 °C compared to 20 °C because of a lower accumulation of chlorpyrifos in the medium at 24 °C. The effects on CTmax could partly be explained by reduction of the aerobic scope. Given that these effects did not differ between latitudes, gradual thermal evolution is not expected to counteract the negative effect of the pesticide on thermal tolerance. By for the first time integrating both interaction pathways we were not only able to provide support for both of them, but more importantly demonstrate that they can directly affect each other. Indeed, the warming-induced reduction in pesticide impact generated a lower pesticide-induced climate change sensitivity (in terms of decreased upper thermal tolerance). Our results indicate that, assuming no increase in pesticide input, global warming might reduce the negative effect of multiple pulse exposures to pesticides on sensitivity to elevated temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis

PubMed Central

Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

2017-01-01

Radiation therapy induces DNA damage and inflammation leading to fibrosis. Fibrosis can occur 4 to 12 months after radiation therapy. This process worsens with time and years. Radiation-induced fibrosis is characterized by fibroblasts proliferation, myofibroblast differentiation, and synthesis of collagen, proteoglycans and extracellular matrix. Myofibroblasts are non-muscle cells that can contract and relax. Myofibroblasts evolve towards irreversible retraction during fibrosis process. In this review, we discussed the interplays between transforming growth factor-β1 (TGF-β1), canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR γ) in regulating the molecular mechanisms underlying the radiation-induced fibrosis, and the potential role of PPAR γ agonists. Overexpression of TGF-β and canonical WNT/β-catenin pathway stimulate fibroblasts accumulation and myofibroblast differentiation whereas PPAR γ expression decreases due to the opposite interplay of canonical WNT/β-catenin pathway. Both TGF-β1 and canonical WNT/β-catenin pathway stimulate each other through the Smad pathway and non-Smad pathways such as phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) signaling. WNT/β-catenin pathway and PPAR γ interact in an opposite manner. PPAR γ agonists decrease β-catenin levels through activation of inhibitors of the WNT pathway such as Smad7, glycogen synthase kinase-3 (GSK-3 β) and dickkopf-related protein 1 (DKK1). PPAR γ agonists also stimulate phosphatase and tensin homolog (PTEN) expression, which decreases both TGF-β1 and PI3K/Akt pathways. PPAR γ agonists by activating Smad7 decrease Smads pathway and then TGF-β signaling leading to decrease radiation-induced fibrosis. TGF-β1 and canonical WNT/β-catenin pathway promote radiation-induced fibrosis whereas PPAR γ agonists can prevent radiation-induced fibrosis. PMID:29163854

Neutrophil Recruitment and Articular Hyperalgesia in Antigen-Induced Arthritis are Modulated by the Cholinergic Anti-Inflammatory Pathway.

PubMed

Kanashiro, Alexandre; Talbot, Jhimmy; Peres, Raphael S; Pinto, Larissa G; Bassi, Gabriel S; Cunha, Thiago M; Cunha, Fernando Q

2016-11-01

The cholinergic anti-inflammatory pathway (CAP) is a complex neuroimmune mechanism triggered by the central nervous system to regulate peripheral inflammatory responses. Understanding the role of CAP in the pathogenesis of rheumatoid arthritis (RA) could help develop new therapeutic strategies for this disease. Therefore, we investigated the participation of this neuroimmune pathway on the progression of experimental arthritis. Using antigen-induced arthritis (AIA) model, we investigated in mice the effects of vagotomy or the pharmacological treatments with hexamethonium (peripheral nicotinic receptor antagonist), methylatropine (peripheral muscarinic receptor antagonist) or neostigmine (peripheral acetylcholinesterase inhibitor) on AIA progression. Unilateral cervical vagotomy was performed 1 week before the immunization protocol with methylated bovine serum albumin (mBSA), while drug administration was conducted during the period of immunization. On day 21, 6 hr after the challenge with mBSA injection in the femur-tibial joint, the local neutrophil migration and articular mechanical hyperalgesia were assessed. Herein, we observed that vagotomy or blockade of peripheral nicotinic (but not muscarinic) receptors exacerbated the clinical parameters of this disease. Moreover, peripheral acetylcholinesterase inhibition by neostigmine treatment promoted a reduction of neutrophil recruitment in the knee joint and articular hyperalgesia. Our results demonstrated that peripheral activation of CAP modulates experimental arthritis, providing a pre-clinical evidence of a potential therapeutic strategy for RA. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Metabolic shift of the kynurenine pathway impairs alcohol and cocaine seeking and relapse.

PubMed

Vengeliene, Valentina; Cannella, Nazzareno; Takahashi, Tatiane; Spanagel, Rainer

2016-09-01

The glutamatergic system plays a key role in the maintenance of drug use and development of drug-related conditioned behaviours. In particular, hyper-glutamatergic activity and N-methyl-D-aspartate receptor (NMDAR) activation may drive drug craving and relapse. Inhibition of kynurenine-3-monooxygenase (KMO) shifts the metabolic kynurenine pathway towards production of kynurenic acid, which leads to a reduction of glutamatergic/NMDAR activity via different mechanisms. In this study, we investigated whether drug-seeking and relapse behaviour could be modified by the metabolic shift of endogenous kynurenine pathway. An inhibitor of kynurenine-3-monooxygenase (KMO) Ro61-8048 (4 and 40 mg/kg) and its prodrug JM6 (100 and 200 mg/kg) were tested in two behavioural rat models for drug seeking and relapse-the alcohol deprivation effect (ADE) model in long-term alcohol-drinking rats and the model of cue-induced reinstatement of alcohol- and cocaine-seeking behaviour. Our results show that relapse-like alcohol drinking during the ADE was abolished by repeated intraperitoneal administration of Ro61-8048 and significantly reduced by its oral prodrug JM6. Cue-induced reinstatement of both alcohol- and cocaine-seeking behaviour was also abolished by administration of Ro61-8048. Pharmacological enhancement of endogenous kynurenic acid levels provides a novel treatment strategy to interfere with glutamatergic/NMDAR activity as well as with craving and relapse in alcohol-dependent patients and drug addicts.

Low oxygen level increases proliferation and metabolic changes in bovine granulosa cells.

PubMed

Shiratsuki, Shogo; Hara, Tomotaka; Munakata, Yasuhisa; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

2016-12-05

The present study addresses molecular backgrounds underlying low oxygen induced metabolic changes and 1.2-fold change in bovine granulosa cell (GCs) proliferation. RNA-seq revealed that low oxygen (5%) upregulated genes associated with HIF-1 and glycolysis and downregulated genes associated with mitochondrial respiration than that in high oxygen level (21%). Low oxygen level induced high glycolytic activity and low mitochondrial function and biogenesis. Low oxygen level enhanced GC proliferation with high expression levels of HIF-1, VEGF, AKT, mTOR, and S6RP, whereas addition of anti-VEGF antibody decreased cellular proliferation with low phosphorylated AKT and mTOR expression levels. Low oxygen level reduced SIRT1, whereas activation of SIRT1 by resveratrol increased mitochondrial replication and decreased cellular proliferation with reduction of phosphorylated mTOR. These results suggest that low oxygen level stimulates the HIF1-VEGF-AKT-mTOR pathway and up-regulates glycolysis, which contributes to GC proliferation, and downregulation of SIRT1 contributes to hypoxia-associated reduction of mitochondria and cellular proliferation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Venom present in sea anemone (Heteractis magnifica) induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria-mediated pathway.

PubMed

Ramezanpour, Mahnaz; da Silva, Karen Burke; Sanderson, Barbara J S

2014-03-01

Lung cancer is a major cause of cancer deaths throughout the world and the complexity of apoptosis resistance in lung cancer is apparent. Venom from Heteractis magnifica caused dose-dependent decreases in survival of the human non-small-cell lung cancer cell line, as determined by the MTT and Crystal Violet assays. The H. magnifica venom induced cell cycle arrest and induced apoptosis of A549 cells, as confirmed by annexin V/propidium iodide staining. The venom-induced apoptosis in A549 cells was characterized by cleavage of caspase-3 and a reduction in the mitochondrial membrane potential. Interestingly, crude extracts from H. magnifica had less effect on the survival of non-cancer cell lines. In the non-cancer cells, the mechanism via which cell death occurred was through necrosis not apoptosis. These findings are important for future work using H. magnifica venom for pharmaceutical development to treat human lung cancer.

MYC-induced reprogramming of glutamine catabolism supports optimal virus replication

PubMed Central

Thai, Minh; Thaker, Shivani K.; Feng, Jun; Du, Yushen; Hu, Hailiang; Ting Wu, Ting; Graeber, Thomas G.; Braas, Daniel; Christofk, Heather R.

2015-01-01

Viruses rewire host cell glucose and glutamine metabolism to meet the bioenergetic and biosynthetic demands of viral propagation. However, the mechanism by which viruses reprogram glutamine metabolism and the metabolic fate of glutamine during adenovirus infection have remained elusive. Here, we show MYC activation is necessary for adenovirus-induced upregulation of host cell glutamine utilization and increased expression of glutamine transporters and glutamine catabolism enzymes. Adenovirus-induced MYC activation promotes increased glutamine uptake, increased use of glutamine in reductive carboxylation and increased use of glutamine in generating hexosamine pathway intermediates and specific amino acids. We identify glutaminase (GLS) as a critical enzyme for optimal adenovirus replication and demonstrate that GLS inhibition decreases replication of adenovirus, herpes simplex virus 1 and influenza A in cultured primary cells. Our findings show that adenovirus-induced reprogramming of glutamine metabolism through MYC activation promotes optimal progeny virion generation, and suggest that GLS inhibitors may be useful therapeutically to reduce replication of diverse viruses. PMID:26561297

CoQ deficiency causes disruption of mitochondrial sulfide oxidation, a new pathomechanism associated with this syndrome.

PubMed

Luna-Sánchez, Marta; Hidalgo-Gutiérrez, Agustín; Hildebrandt, Tatjana M; Chaves-Serrano, Julio; Barriocanal-Casado, Eliana; Santos-Fandila, Ángela; Romero, Miguel; Sayed, Ramy Ka; Duarte, Juan; Prokisch, Holger; Schuelke, Markus; Distelmaier, Felix; Escames, Germaine; Acuña-Castroviejo, Darío; López, Luis C

2017-01-01

Coenzyme Q (CoQ) is a key component of the mitochondrial respiratory chain, but it also has several other functions in the cellular metabolism. One of them is to function as an electron carrier in the reaction catalyzed by sulfide:quinone oxidoreductase (SQR), which catalyzes the first reaction in the hydrogen sulfide oxidation pathway. Therefore, SQR may be affected by CoQ deficiency. Using human skin fibroblasts and two mouse models with primary CoQ deficiency, we demonstrate that severe CoQ deficiency causes a reduction in SQR levels and activity, which leads to an alteration of mitochondrial sulfide metabolism. In cerebrum of Coq9 R239X mice, the deficit in SQR induces an increase in thiosulfate sulfurtransferase and sulfite oxidase, as well as modifications in the levels of thiols. As a result, biosynthetic pathways of glutamate, serotonin, and catecholamines were altered in the cerebrum, and the blood pressure was reduced. Therefore, this study reveals the reduction in SQR activity as one of the pathomechanisms associated with CoQ deficiency syndrome. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

Reductions in the Cardiac Transient Outward K+ Current Ito Caused by Chronic β-Adrenergic Receptor Stimulation Are Partly Rescued by Inhibition of Nuclear Factor κB.

PubMed

Panama, Brian K; Korogyi, Adam S; Aschar-Sobbi, Roozbeh; Oh, Yena; Gray, Charles B B; Gang, Hongying; Brown, Joan Heller; Kirshenbaum, Lorrie A; Backx, Peter H

2016-02-19

The fast transient outward potassium current (Ito,f) plays a critical role in the electrical and contractile properties of the myocardium. Ito,f channels are formed by the co-assembly of the pore-forming α-subunits, Kv4.2 and Kv4.3, together with the accessory β-subunit KChIP2. Reductions of Ito,f are common in the diseased heart, which is also associated with enhanced stimulation of β-adrenergic receptors (β-ARs). We used cultured neonatal rat ventricular myocytes to examine how chronic β-AR stimulation decreases Ito,f. To determine which downstream pathways mediate these Ito,f changes, adenoviral infections were used to inhibit CaMKIIδc, CaMKIIδb, calcineurin, or nuclear factor κB (NF-κB). We observed that chronic β-AR stimulation with isoproterenol (ISO) for 48 h reduced Ito,f along with mRNA expression of all three of its subunits (Kv4.2, Kv4.3, and KChIP2). Inhibiting either CaMKIIδc nor CaMKIIδb did not prevent the ISO-mediated Ito,f reductions, even though CaMKIIδc and CaMKIIδb clearly regulated Ito,f and the mRNA expression of its subunits. Likewise, calcineurin inhibition did not prevent the Ito,f reductions induced by β-AR stimulation despite strongly modulating Ito,f and subunit mRNA expression. In contrast, NF-κB inhibition partly rescued the ISO-mediated Ito,f reductions in association with restoration of KChIP2 mRNA expression. Consistent with these observations, KChIP2 promoter activity was reduced by p65 as well as β-AR stimulation. In conclusion, NF-κB, and not CaMKIIδ or calcineurin, partly mediates the Ito,f reductions induced by chronic β-AR stimulation. Both mRNA and KChIP2 promoter data suggest that the ISO-induced Ito,f reductions are, in part, mediated through reduced KChIP2 transcription caused by NF-κB activation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of trichostatin A on Burkitt's lymphoma cells: Inhibition of EPS8 activity through Phospho-Erk1/2 pathway.

PubMed

Sun, Peipei; Zhou, Xin; He, Yingzhi; Liu, Huimin; Wang, Yuxin; Chen, Yiran; Li, Meifang; He, Yanjie; Li, Guowei; Li, Yuhua

2018-03-18

Histone deacetylase inhibitors (HDACi) manifest great potential for treatment of Burkitt's lymphoma (BL), an aggressive B-cell lymphoma. Epidermal growth factor receptor pathway substrate 8 (EPS8) is confirmed overexpressed and associated with poor prognosis in solid tumors and leukemia. However, EPS8 expression and the relationship between EPS8 and HDACi on BL remains obscure. Here, we hypothesized that trichostatin A (TSA), a pan-HDACi, could inhibit BL cells by downregulating EPS8. We demonstrated that TSA reduced cell viability, induced apoptosis and cell arrest at G0/G1. Mechanismly, TSA attenuated EPS8 and downstream Phospho-Erk1/2 pathway. Knockdown of EPS8 resulted in a significant reduction in cellular proliferation and suppressed Phospho-Erk1/2 pathway activity, particularly when combined with TSA. Conversely, overexpression of EPS8 rescued this phenomenon. Then we showed that the combination of TSA and Epirubicin had a more significant effect when compared with TSA or Epirubicin alone. Finally, knockdown of EPS8 and TSA had a synergistic suppression effect on BALB/c nude mice. In conclusion, this study reveals that TSA affects BL cells by suppressing Phospho-Erk1/2 pathway through downregulating EPS8. Copyright © 2018 Elsevier Inc. All rights reserved.

Cyanidin-3-glucoside inhibits UVB-induced oxidative damage and inflammation by regulating MAP kinase and NF-κB signaling pathways in SKH-1 hairless mice skin.

PubMed

Pratheeshkumar, Poyil; Son, Young-Ok; Wang, Xin; Divya, Sasidharan Padmaja; Joseph, Binoy; Hitron, John Andrew; Wang, Lei; Kim, Donghern; Yin, Yuanqin; Roy, Ram Vinod; Lu, Jian; Zhang, Zhuo; Wang, Yitao; Shi, Xianglin

2014-10-01

Skin cancer is one of the most commonly diagnosed cancers in the United States. Exposure to ultraviolet-B (UVB) radiation induces inflammation and photocarcinogenesis in mammalian skin. Cyanidin-3-glucoside (C3G), a member of the anthocyanin family, is present in various vegetables and fruits especially in edible berries, and displays potent antioxidant and anticarcinogenic properties. In this study, we have assessed the in vivo effects of C3G on UVB irradiation induced chronic inflammatory responses in SKH-1 hairless mice, a well-established model for UVB-induced skin carcinogenesis. Here, we show that C3G inhibited UVB-induced skin damage and inflammation in SKH-1 hairless mice. Our results indicate that C3G inhibited glutathione depletion, lipid peroxidation and myeloperoxidation in mouse skin by chronic UVB exposure. C3G significantly decreased the production of UVB-induced pro-inflammatory cytokines, such as IL-6 and TNF-α, associated with cutaneous inflammation. Likewise, UVB-induced inflammatory responses were diminished by C3G as observed by a remarkable reduction in the levels of phosphorylated MAP kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, C3G also decreased UVB-induced cyclooxygenase-2 (COX-2), PGE2 and iNOS levels, which are well-known key mediators of inflammation and cancer. Treatment with C3G inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mice skin. Immunofluorescence assay revealed that topical application of C3G inhibited the expression of 8-hydroxy-2'-deoxyguanosine, proliferating cell nuclear antigen, and cyclin D1 in chronic UVB exposed mouse skin. Collectively, these data indicates that C3G can provide substantial protection against the adverse effects of UVB radiation by modulating UVB-induced MAP kinase and NF-κB signaling pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

Cyanidin-3-Glucoside inhibits UVB-induced oxidative damage and inflammation by regulating MAP kinase and NF-κB signalling pathways in SKH-1 hairless mice skin

PubMed Central

Pratheeshkumar, Poyil; Son, Young-Ok; Wang, Xin; Divya, Sasidharan Padmaja; Joseph, Binoy; Hitron, John Andrew; Wang, Lei; Kim, Donghern; Yin, Yuanqin; Roy, Ram Vinod; Lu, Jian; Zhang, Zhuo; Wang, Yitao; Shi, Xianglin

2015-01-01

Skin cancer is one of the most commonly diagnosed cancers in the United States. Exposure to ultraviolet-B (UVB) radiation induces inflammation and photocarcinogenesis in mammalian skin. Cyanidin-3-Glucoside (C3G), a member of the anthocyanin family, is present in various vegetables and fruits especially in edible berries, and displays potent antioxidant and anticarcinogenic properties. In this study, we have assessed the in vivo effects of C3G on UVB irradiation induced chronic inflammatory responses in SKH-1 hairless mice, a well-established model for UVB-induced skin carcinogenesis. Here, we show that C3G inhibited UVB-induced skin damage and inflammation in SKH-1 hairless mice. Our results indicate that C3G inhibited glutathione depletion, lipid peroxidation and myeloperoxidation in mouse skin by chronic UVB exposure. C3G significantly decreased the production of UVB-induced pro-inflammatory cytokines, such as IL-6 and TNF-α, associated with cutaneous inflammation. Likewise, UVB-induced inflammatory responses were diminished by C3G as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, C3G also decreased UVB-induced cyclooxygenase-2 (COX-2), PGE2 and iNOS levels, which are well-known key mediators of inflammation and cancer. Treatment with C3G inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mice skin. Immunofluorescence assay revealed that topical application of C3G inhibited the expression of 8-hydroxy-2′-deoxyguanosine, proliferating cell nuclear antigen, and cyclin D1 in chronic UVB exposed mouse skin. Collectively, these data indicates that C3G can provide substantial protection against the adverse effects of UVB radiation by modulating UVB-induced MAP kinase and NF-κB signaling pathways. PMID:25062774

QRFP-43 inhibits lipolysis by preventing ligand-induced complex formation between perilipin A, caveolin-1, the catalytic subunit of protein kinase and hormone-sensitive lipase in 3T3-L1 adipocytes.

PubMed

Mulumba, Mukandila; Granata, Riccarda; Marleau, Sylvie; Ong, Huy

2015-05-01

QRFP (RFamide) peptides are neuropeptides involved in food intake and adiposity regulation in rodents. We have previously shown that QRFP-43 (43RFa) and QRFP-26 (26RFa) inhibited isoproterenol (ISO)-induced lipolysis in adipocytes. However, the antilipolytic signaling pathways activated by QRFP peptides have not been investigated. In the present study, 3T3-L1 adipocytes were used to identify the main pathways involved in QRFP-43 decreasing ISO-induced lipolysis. Our results show that QRFP-43 reduced ISO-induced phosphorylation of perilipin A (PLIN) and hormone-sensitive lipase (HSL) on Ser660 by 43 and 25%, respectively, but increased Akt phosphorylation by 44%. However, the inhibition of phosphodiesterase 3B (PDE3B), a regulator of lipolysis activated by Akt, did not reverse the antilipolytic effect of QRFP-43. PDE3B inhibition reversed the decrease of Ser660 HSL phosphorylation associated with QRFP-43 antilipolytic effect. QRFP-43 also prevented PKC activation and ISO-induced Src kinases activation leading to the inhibition of the caveolin-1 (CAV-1) translocation on lipid droplets. Indeed, QRFP-43 attenuated phorbol 12-myristate 13-acetate-induced lipolysis and ISO-induced extracellular signal-regulated and Src kinases by 28, 37 and 48%, respectively. The attenuation of ISO-induced lipolysis by QRFP-43 was associated with a decrease of phosphorylated Ser660 HSL, PKA-catalytic (PKA-c) subunit and CAV-1 translocation on lipid droplets by 37, 50 and 46%, respectively. The decrease in ISO-induced CAV-1 and PKA-c translocation was associated with a reduction of PLIN phosphorylation by 44% in QRFP-43-treated adipocytes. These results suggest that QRFP-43 attenuated ISO-induced lipolysis by preventing the formation of an active complex on lipid droplets and the activation of Src kinases and PKC. Copyright © 2015. Published by Elsevier B.V.

Astaxanthin reduces isoflurane-induced neuroapoptosis via the PI3K/Akt pathway.

PubMed

Wang, Chun-Mei; Cai, Xiao-Lan; Wen, Qing-Ping

2016-05-01

Astaxanthin is an oxygen-containing derivative of carotenoids that effectively suppresses reactive oxygen and has nutritional and medicinal value. The mechanisms underlying the effects of astaxanthin on isoflurane‑induced neuroapoptosis remain to be fully understood. The present study was conducted to evaluate the protective effect of astaxanthin to reduce isoflurane‑induced neuroapoptosis and to investigate the underlying mechanisms. The results demonstrated that isoflurane induced brain damage, increased caspase‑3 activity and suppressed the phosphatidylinositol 3‑kinase (PI3K)/protein kinase B (Akt) signaling pathway in an in vivo model. However, treatment with astaxanthin significantly inhibited brain damage, suppressed caspase‑3 activity and upregulated the PI3K/Akt pathway in the isoflurane‑induced rats. Furthermore, isoflurane suppressed cell growth, induced cell apoptosis, enhanced caspase‑3 activity and downregulated the PI3K/Akt pathway in organotypic hippocampal slice culture. Administration of astaxanthin significantly promoted cell growth, reduced cell apoptosis and caspase‑3 activity, and upregulated the PI3K/Akt pathway and isoflurane‑induced neuroapoptosis. The present study demonstrated that downregulation of the PI3K/Akt pathway reduced the effect of astaxanthin to protect against isoflurane‑induced neuroapoptosis in the in vitro model. The results of the current study suggested that the protective effect of astaxanthin reduces the isoflurane-induced neuroapoptosis via activation of the PI3K/Akt signaling pathway.

Compromised Mitochondrial Fatty Acid Synthesis in Transgenic Mice Results in Defective Protein Lipoylation and Energy Disequilibrium

PubMed Central

Smith, Stuart; Witkowski, Andrzej; Moghul, Ayesha; Yoshinaga, Yuko; Nefedov, Michael; de Jong, Pieter; Feng, Dejiang; Fong, Loren; Tu, Yiping; Hu, Yan; Young, Stephen G.; Pham, Thomas; Cheung, Carling; Katzman, Shana M.; Brand, Martin D.; Quinlan, Casey L.; Fens, Marcel; Kuypers, Frans; Misquitta, Stephanie; Griffey, Stephen M.; Tran, Son; Gharib, Afshin; Knudsen, Jens; Hannibal-Bach, Hans Kristian; Wang, Grace; Larkin, Sandra; Thweatt, Jennifer; Pasta, Saloni

2012-01-01

A mouse model with compromised mitochondrial fatty acid synthesis has been engineered in order to assess the role of this pathway in mitochondrial function and overall health. Reduction in the expression of mitochondrial malonyl CoA-acyl carrier protein transacylase, a key enzyme in the pathway encoded by the nuclear Mcat gene, was achieved to varying extents in all examined tissues employing tamoxifen-inducible Cre-lox technology. Although affected mice consumed more food than control animals, they failed to gain weight, were less physically active, suffered from loss of white adipose tissue, reduced muscle strength, kyphosis, alopecia, hypothermia and shortened lifespan. The Mcat-deficient phenotype is attributed primarily to reduced synthesis, in several tissues, of the octanoyl precursors required for the posttranslational lipoylation of pyruvate and α-ketoglutarate dehydrogenase complexes, resulting in diminished capacity of the citric acid cycle and disruption of energy metabolism. The presence of an alternative lipoylation pathway that utilizes exogenous free lipoate appears restricted to liver and alone is insufficient for preservation of normal energy metabolism. Thus, de novo synthesis of precursors for the protein lipoylation pathway plays a vital role in maintenance of mitochondrial function and overall vigor. PMID:23077570

New insights into hydrosilylation of unsaturated carbon-heteroatom (C═O, C═N) bonds by rhenium(V)-dioxo complexes.

PubMed

Huang, Liangfang; Wang, Wenmin; Wei, Xiaoqin; Wei, Haiyan

2015-04-23

The hydrosilylation of unsaturated carbon-heteroatom (C═O, C═N) bonds catalyzed by high-valent rhenium(V)-dioxo complex ReO2I(PPh3)2 (1) were studied computationally to determine the underlying mechanism. Our calculations revealed that the ionic outer-sphere pathway in which the organic substrate attacks the Si center in an η(1)-silane rhenium adduct to prompt the heterolytic cleavage of the Si-H bond is the most energetically favorable process for rhenium(V)-dioxo complex 1 catalyzed hydrosilylation of imines. The activation energy of the turnover-limiting step was calculated to be 22.8 kcal/mol with phenylmethanimine. This value is energetically more favorable than the [2 + 2] addition pathway by as much as 10.0 kcal/mol. Moreover, the ionic outer-sphere pathway competes with the [2 + 2] addition mechanism for rhenium(V)-dioxo complex 1 catalyzing the hydrosilylation of carbonyl compounds. Furthermore, the electron-donating group on the organic substrates would induce a better activity favoring the ionic outer-sphere mechanistic pathway. These findings highlight the unique features of high-valent transition-metal complexes as Lewis acids in activating the Si-H bond and catalyzing the reduction reactions.

Small Molecular Weight Soybean Protein-Derived Peptides Nutriment Attenuates Rat Burn Injury-Induced Muscle Atrophy by Modulation of Ubiquitin-Proteasome System and Autophagy Signaling Pathway.

PubMed

Zhao, Fen; Yu, Yonghui; Liu, Wei; Zhang, Jian; Liu, Xinqi; Liu, Lingying; Yin, Huinan

2018-03-21

This article describes results of the effect of dietary supplementation with small molecular weight soybean protein-derived peptides on major rat burn injury-induced muscle atrophy. As protein nutrients have been previously implicated to play an important role in improving burn injury outcomes, optimized more readily absorbed small molecular weight soybean protein-derived peptides were evaluated. Thus, the quantity, sodium dodecyl sulfate polyacrylamide-gel electrophoresis patterns, molecular weight distribution, and composition of amino acids of the prepared peptides were analyzed, and a major full-thickness 30% total body surface area burn-injury rat model was utilized to assess the impact of supplementation with soybean protein-derived peptides on initial systemic inflammatory responses as measured by interferon-gamma (IFN-γ), chemokine (C-C motif) ligand 2 (CCL2, also known as MCP-1), chemokine (C-C motif) ligand 7 (CCL7, also known as MCP-3), and generation of muscle atrophy as measured by tibialis anterior muscle (TAM) weight relative to total body weight. Induction of burn injury-induced muscle atrophy ubiquitin-proteasome system (UPS) signaling pathways in effected muscle tissues was determined by Western blot protein expression measurements of E3 ubiquitin-protein ligase TRIM-63 (TRIM63, also known as MuRF1) and F-box only protein 32 (FBXO32, also known as atrogin-1 or MAFbx). In addition, induction of burn injury-induced autophagy signaling pathways associated with muscle atrophy in effected muscle tissues was assessed by immunohistochemical analysis as measured by microtubule-associated proteins 1 light chain 3 (MAP1LC3, or commonly abbreviated as LC3) and beclin-1 (BECN1) expression, as well as relative induction of cytoplasmic-liberated form of MAP1LC3 (LC3-I) and phagophore and autophagosome membrane-bound form of MAP1LC3 (LC3-II), and BECN1 protein expression by Western blot analysis. Nutrient supplementation with small molecular weight soybean protein-derived peptides resulted a significant reduction in burn injury-induced inflammatory markers, muscle atrophy, induction of TRIM63 and FBXO32 muscle atrophy signaling pathways, and induction of autophagy signaling pathways LC3 and BECN1 associated with muscle atrophy. These results implicated that small molecular weight soybean-derived peptides dietary supplementation could be used as an adjunct therapy in burn injury management to reduce the development or severity of muscle atrophy for improved burn patient outcomes.

Novel Approaches for Delineating and Studying "Hotspots" and "Hot Moments" in Fluvial Environments

NASA Astrophysics Data System (ADS)

Williams, K. H.; Bücker, M.; Flores Orozco, A.; Hobson, C.; Robbins, M.

2014-12-01

Experiments at the Department of Energy's Rifle, CO (USA) field site have long focused on stimulated biogeochemical pathways arising from organic carbon injection. While reductive pathways and their relation to uranium immobilization have been a focus since 2002, ongoing studies are exploring oxidative pathways and their role in mediating fluxes of C, N, S, and aqueous metals. Insights gained from 'stimulation' experiments are providing insight into analogous natural biogeochemical pathways that mediate elemental cycling in the absence of exogenous carbon. Such reactions are instead mediated by endogenous pools of natural organic matter (NOM) deposited during aggradation of aquifer sediments associated with fluvial processes within the Colorado River floodplain. Discrete lenses of fine-grained, organic-rich sediments enriched in reduced species, such as Fe(II) and iron sulfides have been identified along the active margin of the floodplain. Referred to as "naturally reduced zones" (NRZs), these localities constitute a distinct facies type within an otherwise gravel-dominated, largely NOM-deficient matrix. NRZs represent 'hotspots' of seasonally intense C, N, S, and U cycling during excursions in groundwater elevation. Air bubble imbibition within the capillary fringe is inferred to contribute to seasonally oxic groundwater, with its puntuated, 'hot moment' like impact on redox-mediated reactions exhibiting close correspondence to those induced through the intentional introduction of oxidants. Reactions induce sharp gradients in nitrate and sulfate resulting from elevated rates of nitrification and oxidation of reduced sulfur as dissolved oxygen becomes non-limiting. Given their outsized role in constraining the location and timing of critcal element cycling pathways, delineating the distribution of NRZs across scales of relevance to natural field systems is of great importance. Novel mapping approaches borrowed from the field of exploration geophysics provide one means for identifying such 'hotspots' across a variety of environments where their formation is favored. Drilling activities and deployment of monitoring approaches to study cycling pathways of interest and as a function of hydrologic perturbation may then be performed in a targeted and scientificlally-informed manner.

The Strong African American Families program: longitudinal pathways to sexual risk reduction.

PubMed

Murry, Velma McBride; Berkel, Cady; Brody, Gene H; Gerrard, Meg; Gibbons, Meg; Gibbons, Frederick X

2007-10-01

To identify the mechanisms by which intervention-induced increases in adaptive parenting were associated with a reduction in sexual risk behavior among rural African American adolescents across a 29-month period. African American families (N = 284) with 11-year-old children in nine rural Georgian counties participated in the 7-week Strong African American Families (SAAF) project. Counties were randomly assigned to intervention or control conditions. The program was evaluated via pretest, posttest, and long-term follow-up interview data collected in the families' homes. The current paper tests a hypothetical model of program efficacy, positing that intervention-induced changes in parenting behaviors would enhance in youth self-pride, which in turn would forecast changes in sexual behaviors measured 29 months after pretest. Compared with controls, parents who participated in SAAF reported increased adaptive universal and racially specific parenting. Furthermore, intervention-induced changes in these parenting behaviors were associated indirectly with sexual risk behavior through adolescent self-pride, peer orientation, and sexual intent. Culturally competent programs, developed through empirical and theoretical research within affected communities, can foster adaptive universal and racially specific parenting, which can have a long-term effect on adolescent sexual risk behavior. Effective strategies for designing and implementing culturally competent programs are discussed.

Totarol prevents neuronal injury in vitro and ameliorates brain ischemic stroke: Potential roles of Akt activation and HO-1 induction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Yuanxue; Xu, Xiaojun; Chang, Sai

The natural product totarol, a phenolic diterpenoid and a major constituent isolated from the sap of Podocarpus totara, has been reported to have a potent antimicrobial activity. In this study, we determined whether totarol possessed an additional neuroprotective activity in vitro and in vivo. We found that totarol prevented glutamate- and oxygen and glucose deprivation-induced neuronal death in primary rat cerebellar granule neuronal cells and cerebral cortical neurons. Totarol increased Akt and GSK-3β phosphorylation, Nrf2 and heme oxygenase-1 (HO-1) protein expressions and suppressed oxidative stress by increasing GSH and SOD activities. The PI3K/Akt inhibitor LY294002 prevented totarol neuroprotective effect bymore » suppressing the totarol-induced changes in HO-1 expression and the activities of GSH and SOD. The HO-1 inhibitor ZnPPIX also prevented totarol-increased GSH and SOD activities. In a model of acute cerebral ischemic injury in Sprague–Dawley rats, produced by occlusion of the middle cerebral artery for 2 h followed by 22 h or 46 h of reperfusion, totarol significantly reduced infarct volume and improved the neurological deficit. In this model, totarol increased HO-1 expression and the activities of GSH and SOD. These observations suggest that totarol may be a novel activator of the Akt/HO-1 pathway protecting against ischemic stroke through reduction of oxidative stress. - Graphical abstract: It is unknown whether the natural product totarol has neuroprotective effects in vitro and in vivo. This study underscores that totarol prevents neuronal injury in vitro, not only by activating PI3K/Akt pathway, but also via induction of Nrf2, HO-1, GSH and SOD expressions. Totarol also ameliorated acute cerebral ischemic injury in a rat ischemic stroke model. The findings highlight that totarol may be exploited for protecting against ischemic stroke through Akt/HO-1 pathway. - Highlights: • Totarol protects glutamate- and OGD-induced neuronal injury in vitro. • Totarol activates PI3K/Akt pathway in neurons. • Totarol induces HO-1, GSH and SOD expression in vitro and in vivo. • Totarol exhibits neuroprotective effects in rat brain ischemic stroke model.« less

Possible molecular mechanism underlying cadmium-induced circadian rhythms disruption in zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Bo; Chen, Tian-Ming; Zhong, Yingbin

This study was aimed to explore the mechanisms underlying cadmium-induced circadian rhythms disruption. Two groups of zebrafish larvae treated with or without 5 ppm CdCl{sub 2} were incubated in a photoperiod of 14-h light/10-h dark conditions. The mRNA levels of clock1a, bmal1b, per2 and per1b in two groups were determined. Microarray data were generated in two group of samples. Differential expression of genes were identified and the changes in expression level for some genes were validated by RT-PCR. Finally, Gene Ontology functional and KEGG pathway enrichment analysis of differentially expressed genes (DEGs) were performed. In comparison with normal group, the mRNAmore » levels of clock1a, bmal1b, and per2 were significantly changed and varied over the circadian cycle in CdCl2-treated group. DEGs were obtained from the light (84 h, ZT12) and dark (88 h, ZT16) phase. In addition, G-protein coupled receptor protein signaling pathway and immune response were both enriched by DEGs in both groups. While, proteolysis and amino acid metabolism were found associated with DEGs in light phase, and Neuroactive ligand-receptor interaction and oxidation-reduction process were significantly enriched by DEGs in dark phase. Besides, the expression pattern of genes including hsp70l and or115-11 obtained by RT-PCR were consistent with those obtained by microarray analysis. As a consequence, cadmium could make significant effects on circadian rhythms through immune response and G protein-coupled receptor signaling pathway. Besides, between the dark and the light phase, the mechanism by which cadmium inducing disruption of circadian rhythms were different to some extent. - Highlights: • Cadmium could affect the expression levels of circadian rhythm-related genes. • Genes expression in microarray data were consistent with those in RT-PCR analysis. • Immune response and G protein-coupled receptor signaling pathway were identified. • Cadmium induces circadian rhythm disruption by different mechanism in day and night.« less

Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR

PubMed Central

Wang, Tongtong; Zhang, Xiujuan; Chen, Yu; Cui, Beibei; Li, Delong; Zhao, Xiaomin; Zhang, Wenlong; Chang, Lingling; Tong, Dewen

2016-01-01

Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages. PMID:26883107

Endogenously Released Neuropeptide Y Suppresses Hippocampal Short-Term Facilitation and Is Impaired by Stress-Induced Anxiety

PubMed Central

Li, Qin; Bartley, Aundrea F.

2017-01-01

Neuropeptide Y (NPY) has robust anxiolytic properties and is reduced in patients with anxiety disorders. However, the mechanisms by which NPY modulates circuit function to reduce anxiety behavior are not known. Anxiolytic effects of NPY are mediated in the CA1 region of hippocampus, and NPY injection into hippocampus alleviates anxiety symptoms in the predator scent stress model of stress-induced anxiety. The mechanisms that regulate NPY release, and its effects on CA1 synaptic function, are not fully understood. Here we show in acute hippocampal slices from mice that endogenous NPY, released in response to optogenetic stimulation or synaptically evoked spiking of NPY+ cells, suppresses both of the feedforward pathways to CA1. Stimulation of temporoammonic synapses with a physiologically derived spike train causes NPY release that reduces short-term facilitation, whereas the release of NPY that modulates Schaffer collateral synapses requires integration of both the Schaffer collateral and temporoammonic pathways. Pathway specificity of NPY release is conferred by three functionally distinct NPY+ cell types, with differences in intrinsic excitability and short-term plasticity of their inputs. Predator scent stress abolishes the release of endogenous NPY onto temporoammonic synapses, a stress-sensitive pathway, thereby causing enhanced short-term facilitation. Our results demonstrate how stress alters CA1 circuit function through the impairment of endogenous NPY release, potentially contributing to heightened anxiety. SIGNIFICANCE STATEMENT Neuropeptide Y (NPY) has robust anxiolytic properties, and its levels are reduced in patients with post-traumatic stress disorder. The effects of endogenously released NPY during physiologically relevant stimulation, and the impact of stress-induced reductions in NPY on circuit function, are unknown. By demonstrating that NPY release modulates hippocampal synaptic plasticity and is impaired by predator scent stress, our results provide a novel mechanism by which stress-induced anxiety alters circuit function. These studies fill an important gap in knowledge between the molecular and behavioral effects of NPY. This article also advances the understanding of NPY+ cells and the factors that regulate their spiking, which could pave the way for new therapeutic targets to increase endogenous NPY release in patients in a spatially and temporally appropriate manner. PMID:28053027

Hydrogen sulfide (H2S) attenuates uranium-induced acute nephrotoxicity through oxidative stress and inflammatory response via Nrf2-NF-κB pathways.

PubMed

Zheng, Jifang; Zhao, Tingting; Yuan, Yan; Hu, Nan; Tang, Xiaoqing

2015-12-05

As an endogenous gaseous mediator, H2S exerts anti-oxidative, anti-inflammatory and cytoprotective effects in kidneys. This study was designed to investigate the protective effect of H2S against uranium-induced nephrotoxicity in adult SD male rats after in vivo effect of uranium on endogenous H2S formation was explored in kidneys. The levels of endogenous H2S and H2S-producing enzymes (CBS and CSE) were measured in renal homogenates from rats intoxicated by an intraperitoneally (i.p.) injection of uranyl acetate at a single dose of 2.5, 5 or 10 mg/kg. In rats injected i.p. with uranyl acetate (5 mg/kg) or NaHS (an H2S donor, 28 or 56 μmol/kg) alone or in combination, we determined biochemical parameters and histopathological alteration to assess kidney function, examined oxidative stress markers, and investigated Nrf2 and NF-κB pathways in kidney homogenates. The results suggest that uranium intoxication in rats decreased endogenous H2S generation as well as CBS and CSE protein expression. NaHS administration in uranium-intoxicated rats ameliorated the renal biochemical indices and histopathological effects, lowered MDA accumulation, and restored GSH level and anti-oxidative enzymes activities like SOD, CAT, GPx and GST. NaHS treatment in uranium-intoxicated rats activated uranium-inhibited protein expression and nuclear translocation of transcription factor Nrf2, which increased protein expression of downstream target-Nrf2 genes HO-1, NQO-1, GCLC, and TXNRD-1. NaHS administration in uranium-intoxicated rats inhibited uranium-induced nuclear translocation and phosphorylation of transcription factor κB/p65, which decreased protein expression of target-p65 inflammatory genes TNF-α, iNOS, and COX-2. Taken together, these data implicate that H2S can afford protection to rat kidneys against uranium-induced adverse effects through induction of antioxidant defense by activating Nrf2 pathway and reduction of inflammatory response by suppressing NF-κB pathway. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A TIGAR-regulated metabolic pathway is critical for protection of brain ischemia.

PubMed

Li, Mei; Sun, Meiling; Cao, Lijuan; Gu, Jin-hua; Ge, Jianbin; Chen, Jieyu; Han, Rong; Qin, Yuan-Yuan; Zhou, Zhi-Peng; Ding, Yuqiang; Qin, Zheng-Hong

2014-05-28

TP53-induced glycolysis and apoptosis regulator (TIGAR) inhibits glycolysis and increases the flow of pentose phosphate pathway (PPP), which generates NADPH and pentose. We hypothesized that TIGAR plays a neuroprotective role in brain ischemia as neurons do not rely on glycolysis but are vulnerable to oxidative stress. We found that TIGAR was highly expressed in brain neurons and was rapidly upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. Overexpression of TIGAR in normal mice with lentivirus reduced ischemic neuronal injury, whereas lentivirus-mediated TIGAR knockdown aggravated it. In cultured primary neurons, increasing TIGAR expression reduced oxygen and glucose deprivation (OGD)/reoxygenation-induced injury, whereas decreasing its expression worsened the injury. The glucose 6-phosphate dehydrogenase was upregulated in mouse and cellular models of stroke, and its upregulation was further enhanced by overexpression of TIGAR. Supplementation of NADPH also reduced ischemia/reperfusion brain injury and alleviated TIGAR knockdown-induced aggravation of ischemic injury. In animal and cellular stroke models, ischemia/reperfusion increased mitochondrial localization of TIGAR. OGD/reoxygenation-induced elevation of ROS, reduction of GSH, dysfunction of mitochondria, and activation of caspase-3 were rescued by overexpression of TIGAR or supplementation of NADPH, while knockdown of TIGAR aggravated these changes. Together, our results show that TIGAR protects ischemic brain injury via enhancing PPP flux and preserving mitochondria function, and thus may be a valuable therapeutic target for ischemic brain injury. Copyright © 2014 the authors 0270-6474/14/347458-14$15.00/0.

Ferulic acid attenuates diabetes-induced cognitive impairment in rats via regulation of PTP1B and insulin signaling pathway.

PubMed

Wang, Hao; Sun, Xiaoxu; Zhang, Ning; Ji, Zhouye; Ma, Zhanqiang; Fu, Qiang; Qu, Rong; Ma, Shiping

2017-12-01

Cognitive impairment has been recognized as a typical characteristic of neurodegenerative disease in diabetes mellitus (DM) and this cognitive dysfunction may be a risk factor for Alzheimer's disease (AD). Ferulic acid, a phenolic compound commonly found in a range of plants, has emerged various properties including anti-inflammatory and neuroprotective effects. In the present study, the protective activities and relevant mechanisms of ferulic acid were evaluated in diabetic rats with cognitive deficits, which were induced by a high-glucose-fat (HGF) diet and low dose of streptozotocin (STZ). It was observed that ferulic acid significantly increased body weight and decreased blood glucose levels. Meanwhile, ferulic acid could markedly ameliorate spatial memory of diabetic rats in Morris water maze (MWM) and decrease AD-like pathologic changes (Aβ deposition and Tau phosphorylation) in the hippocampus, which might be correlated with the inhibition of inflammatory cytokines release and reduction of protein tyrosine phosphatase 1B (PTP1B) expression. Moreover, the levels of brain insulin signal molecules p-IRS, p-Akt and p-GSK3β were also investigated. We found that ferulic acid administration restored the alterations in insulin signaling. In conclusion, ferulic acid exhibited beneficial effects on diabetes-induced cognition lesions, which was involved in the regulation of PTP1B and insulin signaling pathway. We suppose that PTP1B inhibition may represent a promising approach to correct abnormal signaling linked to diabetes-induced cognitive impairment. Copyright © 2017. Published by Elsevier Inc.

DNA damage-induced nuclear translocation of Apaf-1 is mediated by nucleoporin Nup107

PubMed Central

Jagot-Lacoussiere, Léonard; Faye, Audrey; Bruzzoni-Giovanelli, Heriberto; Villoutreix, Bruno O; Rain, Jean-Christophe; Poyet, Jean-Luc

2015-01-01

Beside its central role in the mitochondria-dependent cell death pathway, the apoptotic protease activating factor 1 (Apaf-1) is involved in the DNA damage response through cell-cycle arrest induced by genotoxic stress. This non-apoptotic function requires a nuclear translocation of Apaf-1 during the G1-to-S transition. However, the mechanisms that trigger the nuclear accumulation of Apaf-1 upon DNA damage remain to be investigated. Here we show that the main 4 isoforms of Apaf-1 can undergo nuclear translocation and restore Apaf-1 deficient MEFs cell cycle arrest in the S phase following genotoxic stress through activation of Chk-1. Interestingly, DNA damage-dependent nuclear accumulation of Apaf-1 occurs independently of p53 and the retinoblastoma (pRb) pathway. We demonstrated that Apaf-1 associates with the nucleoporin Nup107 and this association is necessary for Apaf-1 nuclear import. The CED-4 domain of Apaf-1 directly binds to the central domain of Nup107 in an ATR-regulated, phosphorylation-dependent manner. Interestingly, expression of the Apaf-1-interacting domain of Nup107 interfered with Apaf-1 nuclear translocation upon genotoxic stress, resulting in a marked reduction of Chk-1 activation and cell cycle arrest. Thus, our results confirm the crucial role of Apaf-1 nuclear relocalization in mediating cell-cycle arrest induced by genotoxic stress and implicate Nup107 as a critical regulator of the DNA damage-induced intra-S phase checkpoint response. PMID:25695197

Chronic nandrolone administration induces dysfunction of the reward pathway in rats.

PubMed

Zotti, Margherita; Tucci, Paolo; Colaianna, Marilena; Morgese, Maria Grazia; Mhillaj, Emanuela; Schiavone, Stefania; Scaccianoce, Sergio; Cuomo, Vincenzo; Trabace, Luigia

2013-10-24

Data in animal models and surveys in humans have shown psychiatric complications of long-term anabolic androgenic steroids abuse. However, neurobiochemical mechanisms behind observed behavioral changes are poorly understood. The aim of the present study was to investigate the effects of nandrolone decanoate on emotional behavior and neurochemical brain alterations in gonadally intact male rats. Behavioral reactivity to elevated plus maze and social interaction test was used to assess anxiety-related symptoms, while sucrose preference test was used to evaluate anhedonia. Dopaminergic, serotonergic and noradrenergic transmissions were also evaluated in selected brain areas. Chronic administration of nandrolone, at 5 mg kg -1 injected for 4 weeks, induced loss of sweet taste preference, as sign of anhedonia and dysfunction of reward pathway. Behavioral outcomes were accompanied by reduction of dopamine, serotonin and noradrenaline contents in nucleus accumbens. Neither alterations in time spent in open arms nor in social interaction test were found, suggesting that nandrolone did not induce an anxiogenic profile. No differences were revealed between experimental groups in the amygdala in terms of neurotransmitters measured. Our data suggest that nandrolone-treated rats have a depressive, but not anxiogenic-like, profile, accompanied by brain region-dependent changes in dopaminergic, serotonergic and noradrenergic neurotransmission. As anabolic androgenic steroid dependence is plausibly the major form of worldwide substance dependence that remains largely unexplored, it should be underlined that our data could contribute to a better understanding of altered reward induced by nandrolone treatment and to develop appropriate treatment. Copyright © 2013. Published by Elsevier Inc.

Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate.

PubMed

Thorup, Casper; Schramm, Andreas; Findlay, Alyssa J; Finster, Kai W; Schreiber, Lars

2017-07-18

This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase. IMPORTANCE Sulfide oxidation and sulfate reduction, the two major branches of the sulfur cycle, are usually ascribed to distinct sets of microbes with distinct diagnostic genes. Here we show a more complex picture, as D. alkaliphilus , with the genomic setup of a sulfate reducer, grows by sulfide oxidation. The high expression of genes typically involved in the sulfate reduction pathway suggests that these genes, including the reductive-type dissimilatory bisulfite reductases, are also involved in as-yet-unresolved sulfide oxidation pathways. Finally, D. alkaliphilus is closely related to cable bacteria, which grow by electrogenic sulfide oxidation. Since there are no pure cultures of cable bacteria, D. alkaliphilus may represent an exciting model organism in which to study the physiology of this process. Copyright © 2017 Thorup et al.

Delayed progression of diabetic cataractogenesis and retinopathy by Litchi chinensis in STZ-induced diabetic rats.

PubMed

Kilari, Eswar Kumar; Putta, Swathi

2017-03-01

The study was carried out to evaluate the effect of the aqueous fruit pericarp extract of Litchi chinensis (APLC) on parameters which leads to diabetic cataractogenesis and retinopathy in the streptozotocin-induced diabetic rats. The objective of the study is to evaluate the APLC for in vivo antioxidant activity and its role in inhibiting the polyol pathway and formation of advanced glycation end products (AGEs). The diabetic animals were treated with L. chinensis for a period of 12 weeks. At the end of 12 weeks, the animals were killed and the biochemical pathways involved in the pathogenesis of cataract such as oxidative stress by protein content, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and polyolpathway by aldose reductase (AR) in lens homogenates, alterations in protein carbonyl content (PCO) and AGEs in both serum and lens the APLC-treated diabetic rats were compared against diabetic control rats. Cataract progression due to hyperglycemia was monitored by slit lamp bio microscope and classified into four stages. Fundoscope test and retinal histopathology were done for assessing retinopathy. Statistically significant reduction in glucose, and elevation of protein content, SOD, CAT, and GSH levels and decreased levels of AR and PCO in lens homogenate and significant reduction in AGEs serum and lens homogenate were observed. Slit lamp examination, fundoscope, and histopathology showed improvement in retinal changes in APLC-treated rats compared to diabetic control animals. The treatment with APLC found to delay the progression of diabetic cataractogenesis and retinopathy, which might be due to its antioxidant activity, because of the presence of active phytochemicals in APLC.

Anti-VEGF treatment reduces blood supply and increases tumor cell invasion in glioblastoma.

PubMed

Keunen, Olivier; Johansson, Mikael; Oudin, Anaïs; Sanzey, Morgane; Rahim, Siti A Abdul; Fack, Fred; Thorsen, Frits; Taxt, Torfinn; Bartos, Michal; Jirik, Radovan; Miletic, Hrvoje; Wang, Jian; Stieber, Daniel; Stuhr, Linda; Moen, Ingrid; Rygh, Cecilie Brekke; Bjerkvig, Rolf; Niclou, Simone P

2011-03-01

Bevacizumab, an antibody against vascular endothelial growth factor (VEGF), is a promising, yet controversial, drug in human glioblastoma treatment (GBM). Its effects on tumor burden, recurrence, and vascular physiology are unclear. We therefore determined the tumor response to bevacizumab at the phenotypic, physiological, and molecular level in a clinically relevant intracranial GBM xenograft model derived from patient tumor spheroids. Using anatomical and physiological magnetic resonance imaging (MRI), we show that bevacizumab causes a strong decrease in contrast enhancement while having only a marginal effect on tumor growth. Interestingly, dynamic contrast-enhanced MRI revealed a significant reduction of the vascular supply, as evidenced by a decrease in intratumoral blood flow and volume and, at the morphological level, by a strong reduction of large- and medium-sized blood vessels. Electron microscopy revealed fewer mitochondria in the treated tumor cells. Importantly, this was accompanied by a 68% increase in infiltrating tumor cells in the brain parenchyma. At the molecular level we observed an increase in lactate and alanine metabolites, together with an induction of hypoxia-inducible factor 1α and an activation of the phosphatidyl-inositol-3-kinase pathway. These data strongly suggest that vascular remodeling induced by anti-VEGF treatment leads to a more hypoxic tumor microenvironment. This favors a metabolic change in the tumor cells toward glycolysis, which leads to enhanced tumor cell invasion into the normal brain. The present work underlines the need to combine anti-angiogenic treatment in GBMs with drugs targeting specific signaling or metabolic pathways linked to the glycolytic phenotype.

Ascending caudal medullary catecholamine pathways drive sickness-induced deficits in exploratory behavior: brain substrates for fatigue?

PubMed

Gaykema, Ronald P A; Goehler, Lisa E

2011-03-01

Immune challenges can lead to marked behavioral changes, including fatigue, reduced social interest, anorexia, and somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. Part of the neurocircuitry influencing behavior associated with illness likely includes viscerosensory nuclei located in the caudal brainstem, based on findings that inactivation of the dorsal vagal complex (DVC) can prevent social withdrawal. These brainstem nuclei contribute multiple neuronal projections that target different components of autonomic and stress-related neurocircuitry. In particular, catecholaminergic neurons in the ventrolateral medulla (VLM) and DVC target the hypothalamus and drive neuroendocrine responses to immune challenge, but their particular role in sickness behavior is not known. To test whether this catecholamine pathway also mediates sickness behavior, we compared effects of DVC inactivation with targeted lesion of the catecholamine pathway on exploratory behavior, which provides an index of motivation and fatigue, and associated patterns of brain activation assessed by immunohistochemical detection of c-Fos protein. LPS treatment dramatically reduced exploratory behavior, and produced a pattern of increased c-Fos expression in brain regions associated with stress and autonomic adjustments paraventricular hypothalamus (PVN), bed nucleus of the stria terminalis (BST), central amygdala (CEA), whereas activation was reduced in regions involved in exploratory behavior (hippocampus, dorsal striatum, ventral tuberomammillary nucleus, and ventral tegmental area). Both DVC inactivation and catecholamine lesion prevented reductions in exploratory behavior and completely blocked the inhibitory LPS effects on c-Fos expression in the behavior-associated regions. In contrast, LPS-induced activation in the CEA and BST was inhibited by DVC inactivation but not by catecholamine lesion. The findings support the idea that parallel pathways from immune-sensory caudal brainstem sources target distinct populations of forebrain neurons that likely mediate different aspects of sickness. The caudal medullary catecholaminergic projections to the hypothalamus may significantly contribute to brain mechanisms that induce behavioral "fatigue" in the context of physiological stressors. Copyright © 2010 Elsevier Inc. All rights reserved.

Ascending caudal medullary catecholamine pathways drive sickness-induced deficits in exploratory behavior: brain substrates for fatigue?

PubMed Central

Gaykema, Ronald P.A.; Goehler, Lisa E.

2010-01-01

Immune challenges can lead to marked behavioral changes, including fatigue, reduced social interest, anorexia, and somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. Part of the neurocircuitry influencing behavior associated with illness likely includes viscerosensory nuclei located in the caudal brainstem, based on findings that inactivation of the dorsal vagal complex (DVC) can prevent social withdrawal. These brainstem nuclei contribute multiple neuronal projections that target different components of autonomic and stress-related neurocircuitry. In particular, catecholaminergic neurons in the ventrolateral medulla (VLM) and DVC target the hypothalamus and drive neuroendocrine responses to immune challenge, but their particular role in sickness behavior is not known. To test whether this catecholamine pathway also mediates sickness behavior, we compared effects of DVC inactivation with targeted lesion of the catecholamine pathway on exploratory behavior, which provides an index of motivation and fatigue, and associated patterns of brain activation assessed by immunohistochemical detection of c-Fos protein. LPS treatment dramatically reduced exploratory behavior, and produced a pattern of increased c-Fos expression in brain regions associated with stress and autonomic adjustments paraventricular hypothalamus (PVN), bed nucleus of the stria terminalis (BST), central amygdala (CEA), whereas activation was reduced in regions involved in exploratory behavior (hippocampus, dorsal striatum, ventral tuberomammillary nucleus, and ventral tegmental area). Both DVC inactivation and catecholamine lesion prevented reductions in exploratory behavior and completely blocked the inhibitory LPS effects on c-Fos expression in the behavior-associated regions. In contrast, LPS-induced activation in the CEA and BST was inhibited by DVC inactivation but not by catecholamine lesion. The findings support the idea that parallel pathways from immune-sensory caudal brainstem sources target distinct populations of forebrain neurons that likely mediate different aspects of sickness. The caudal medullary catecholaminergic projections to the hypothalamus may significantly contribute to brain mechanisms that induce behavioral “fatigue” in the context of physiological stressors. PMID:21075199

Increasing kynurenine brain levels reduces ethanol consumption in mice by inhibiting dopamine release in nucleus accumbens.

PubMed

Giménez-Gómez, Pablo; Pérez-Hernández, Mercedes; Gutiérrez-López, María Dolores; Vidal, Rebeca; Abuin-Martínez, Cristina; O'Shea, Esther; Colado, María Isabel

2018-06-01

Recent research suggests that ethanol (EtOH) consumption behaviour can be regulated by modifying the kynurenine (KYN) pathway, although the mechanisms involved have not yet been well elucidated. To further explore the implication of the kynurenine pathway in EtOH consumption we inhibited kynurenine 3-monooxygenase (KMO) activity with Ro 61-8048 (100 mg/kg, i.p.), which shifts the KYN metabolic pathway towards kynurenic acid (KYNA) production. KMO inhibition decreases voluntary binge EtOH consumption and EtOH preference in mice subjected to "drinking in the dark" (DID) and "two-bottle choice" paradigms, respectively. This effect seems to be a consequence of increased KYN concentration, since systemic KYN administration (100 mg/kg, i.p.) similarly deters binge EtOH consumption in the DID model. Despite KYN and KYNA being well-established ligands of the aryl hydrocarbon receptor (AhR), administration of AhR antagonists (TMF 5 mg/kg and CH-223191 20 mg/kg, i.p.) and of an agonist (TCDD 50 μg/kg, intragastric) demonstrates that signalling through this receptor is not involved in EtOH consumption behaviour. Ro 61-8048 did not alter plasma acetaldehyde concentration, but prevented EtOH-induced dopamine release in the nucleus accumbens shell. These results point to a critical involvement of the reward circuitry in the reduction of EtOH consumption induced by KYN and KYNA increments. PNU-120596 (3 mg/kg, i.p.), a positive allosteric modulator of α7-nicotinic acetylcholine receptors, partially prevented the Ro 61-8048-induced decrease in EtOH consumption. Overall, our results highlight the usefulness of manipulating the KYN pathway as a pharmacological tool for modifying EtOH consumption and point to a possible modulator of alcohol drinking behaviour. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic mathematical modeling of IL13-induced signaling in Hodgkin and primary mediastinal B-cell lymphoma allows prediction of therapeutic targets.

PubMed

Raia, Valentina; Schilling, Marcel; Böhm, Martin; Hahn, Bettina; Kowarsch, Andreas; Raue, Andreas; Sticht, Carsten; Bohl, Sebastian; Saile, Maria; Möller, Peter; Gretz, Norbert; Timmer, Jens; Theis, Fabian; Lehmann, Wolf-Dieter; Lichter, Peter; Klingmüller, Ursula

2011-02-01

Primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (cHL) share a frequent constitutive activation of JAK (Janus kinase)/STAT signaling pathway. Because of complex, nonlinear relations within the pathway, key dynamic properties remained to be identified to predict possible strategies for intervention. We report the development of dynamic pathway models based on quantitative data collected on signaling components of JAK/STAT pathway in two lymphoma-derived cell lines, MedB-1 and L1236, representative of PMBL and cHL, respectively. We show that the amounts of STAT5 and STAT6 are higher whereas those of SHP1 are lower in the two lymphoma cell lines than in normal B cells. Distinctively, L1236 cells harbor more JAK2 and less SHP1 molecules per cell than MedB-1 or control cells. In both lymphoma cell lines, we observe interleukin-13 (IL13)-induced activation of IL4 receptor α, JAK2, and STAT5, but not of STAT6. Genome-wide, 11 early and 16 sustained genes are upregulated by IL13 in both lymphoma cell lines. Specifically, the known STAT-inducible negative regulators CISH and SOCS3 are upregulated within 2 hours in MedB-1 but not in L1236 cells. On the basis of this detailed quantitative information, we established two mathematical models, MedB-1 and L1236 model, able to describe the respective experimental data. Most of the model parameters are identifiable and therefore the models are predictive. Sensitivity analysis of the model identifies six possible therapeutic targets able to reduce gene expression levels in L1236 cells and three in MedB-1. We experimentally confirm reduction in target gene expression in response to inhibition of STAT5 phosphorylation, thereby validating one of the predicted targets.

Xenon Protects Against Septic Acute Kidney Injury via miR-21 Target Signaling Pathway.

PubMed

Jia, Ping; Teng, Jie; Zou, Jianzhou; Fang, Yi; Wu, Xie; Liang, Mingyu; Ding, Xiaoqiang

2015-07-01

Septic acute kidney injury is one of the most common and life-threatening complications in critically ill patients, and there is no approved effective treatment. We have shown xenon provides renoprotection against ischemia-reperfusion injury and nephrotoxicity in rodents via inhibiting apoptosis. Here, we studied the effects of xenon preconditioning on septic acute kidney injury and its mechanism. Experimental animal investigation. University research laboratory. Experiments were performed with male C57BL/6 mice, 10 weeks of age, weighing 20-25 g. We induced septic acute kidney injury by a single intraperitoneal injection of Escherichia coli lipopolysaccharide at a dose of 20 mg/kg. Mice were exposed for 2 hours to either 70% xenon or 70% nitrogen, 24 hours before the onset of septic acute kidney injury. In vivo knockdown of miR-21 was performed using locked nucleic acid-modified anti-miR, the role of miR-21 in renal protection conferred by the xenon preconditioning was examined, and miR-21 signaling pathways were analyzed. Xenon preconditioning provided morphologic and functional renoprotection, characterized by attenuation of renal tubular damage, apoptosis, and a reduction in inflammation. Furthermore, xenon treatment significantly upregulated the expression of miR-21 in kidney, suppressed proinflammatory factor programmed cell death protein 4 expression and nuclear factor-κB activity, and increased interleukin-10 production. Meanwhile, xenon preconditioning also suppressed the expression of proapoptotic protein phosphatase and tensin homolog deleted on chromosome 10, activating protein kinase B signaling pathway, subsequently increasing the expression of antiapoptotic B-cell lymphoma-2, and inhibiting caspase-3 activity. Knockdown of miR-21 upregulated its target effectors programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10 expression, resulted in an increase in apoptosis, and exacerbated lipopolysaccharide-induced acute kidney injury. Our findings demonstrated that xenon preconditioning protected against lipopolysaccharide-induced acute kidney injury via activation of miR-21 target signaling pathways.

Melatonin attenuates D-galactose-induced memory impairment, neuroinflammation and neurodegeneration via RAGE/NF-K B/JNK signaling pathway in aging mouse model.

PubMed

Ali, Tahir; Badshah, Haroon; Kim, Tae Hyun; Kim, Myeong Ok

2015-01-01

Melatonin acts as a pleiotropic agent in various age-related neurodegenerative diseases. In this study, we examined the underlying neuroprotective mechanism of melatonin against D-galactose-induced memory and synaptic dysfunction, elevated reactive oxygen species (ROS), neuroinflammation and neurodegeneration. D-galactose was administered (100 mg/kg intraperitoneally (i.p.)) for 60 days. After 30 days of D-galactose administration, vehicle (same volume) or melatonin (10 mg/kg, i.p.) was administered for 30 days. Our behavioral (Morris water maze and Y-maze test) results revealed that chronic melatonin treatment alleviated D-galactose-induced memory impairment. Additionally, melatonin treatment reversed D-galactose-induced synaptic disorder via increasing the level of memory-related pre-and postsynaptic protein markers. We also determined that melatonin enhances memory function in the D-galactose-treated mice possibly via reduction of elevated ROS and receptor for advanced glycation end products (RAGE). Furthermore, Western blot and morphological results showed that melatonin treatment significantly reduced D-galactose-induced neuroinflammation through inhibition of microgliosis (Iba-1) and astrocytosis (GFAP), and downregulating other inflammatory mediators such as p-IKKβ, p-NF-K B65, COX2, NOS2, IL-1β, and TNFα. Moreover, melatonin lowered the oxidative stress kinase p-JNK which suppressed various apoptotic markers, that is, cytochrome C, caspase-9, caspase-3 and PARP-1, and prevent neurodegeneration. Hence, melatonin attenuated the D-galactose-induced memory impairment, neuroinflammation and neurodegeneration possibly through RAGE/NF-K B/JNK pathway. Taken together, our data suggest that melatonin could be a promising, safe and endogenous compatible antioxidant candidate for age-related neurodegenerative diseases such as Alzheimer's disease (AD). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Go-6976 Reverses Hyperglycemia-Induced Insulin Resistance Independently of cPKC Inhibition in Adipocytes

PubMed Central

Robinson, Katherine A.; Hegyi, Krisztina; Hannun, Yusuf A.; Buse, Maria G.; Sethi, Jaswinder K.

2014-01-01

Chronic hyperglycemia induces insulin resistance by mechanisms that are incompletely understood. One model of hyperglycemia-induced insulin resistance involves chronic preincubation of adipocytes in the presence of high glucose and low insulin concentrations. We have previously shown that the mTOR complex 1 (mTORC1) plays a partial role in the development of insulin resistance in this model. Here, we demonstrate that treatment with Go-6976, a widely used “specific” inhibitor of cPKCs, alleviates hyperglycemia-induced insulin resistance. However, the effects of mTOR inhibitor, rapamycin and Go-6976 were not additive and only rapamycin restored impaired insulin-stimulated AKT activation. Although, PKCα, (but not –β) was abundantly expressed in these adipocytes, our studies indicate cPKCs do not play a major role in causing insulin-resistance in this model. There was no evidence of changes in the expression or phosphorylation of PKCα, and PKCα knock-down did not prevent the reduction of insulin-stimulated glucose transport. This was also consistent with lack of IRS-1 phosphorylation on Ser-24 in hyperglycemia-induced insulin-resistant adipocytes. Treatment with Go-6976 did inhibit a component of the mTORC1 pathway, as evidenced by decreased phosphorylation of S6 ribosomal protein. Raptor knock-down enhanced the effect of insulin on glucose transport in insulin resistant adipocytes. Go-6976 had the same effect in control cells, but was ineffective in cells with Raptor knock-down. Taken together these findings suggest that Go-6976 exerts its effect in alleviating hyperglycemia-induced insulin-resistance independently of cPKC inhibition and may target components of the mTORC1 signaling pathway. PMID:25330241

Mechanism of protection of transepithelial barrier function by Lactobacillus salivarius: strain dependence and attenuation by bacteriocin production.

PubMed

Miyauchi, Eiji; O'Callaghan, John; Buttó, Ludovica F; Hurley, Gráinne; Melgar, Silvia; Tanabe, Soichi; Shanahan, Fergus; Nally, Kenneth; O'Toole, Paul W

2012-11-01

Enhanced barrier function is one mechanism whereby commensals and probiotic bacteria limit translocation of foreign antigens or pathogens in the gut. However, barrier protection is not exhibited by all probiotic or commensals and the strain-specific molecules involved remain to be clarified. We evaluated the effects of 33 individual Lactobacillus salivarius strains on the hydrogen peroxide (H(2)O(2))-induced barrier impairment in human epithelial Caco-2 cells. These strains showed markedly different effects on H(2)O(2)-induced reduction in transepithelial resistance (TER). The effective strains such as UCC118 and CCUG38008 attenuated H(2)O(2)-induced disassembly and relocalization of tight junction proteins, but the ineffective strain AH43324 did not. Strains UCC118 and CCUG38008 induced phosphorylation of extracellular signal-regulated kinase (ERK) in Caco-2 cells, and the ERK inhibitor U0126 attenuated the barrier-protecting effect of these strains. In contrast, the AH43324 strain induced phosphorylation of Akt and p38, which was associated with an absence of a protective effect. Global transcriptome analysis of UCC118 and AH43324 revealed that some genes in a bacteriocin gene cluster were upregulated in AH43324 under TER assay conditions. A bacteriocin-negative UCC118 mutant displayed significantly greater suppressive effect on H(2)O(2)-induced reduction in TER compared with wild-type UCC118. The wild-type strain augmented H(2)O(2)-induced phosphorylation of Akt and p38, whereas a bacteriocin-negative UCC118 mutant did not. These observations indicate that L. salivarius strains are widely divergent in their capacity for barrier protection, and this is underpinned by differences in the activation of intracellular signaling pathways. Furthermore, bacteriocin production appears to have an attenuating influence on lactobacillus-mediated barrier protection.

Role of IL-1 beta and COX2 in silica-induced IL-6 release and loss of pneumocytes in co-cultures.

PubMed

Herseth, Jan I; Refsnes, Magne; Låg, Marit; Schwarze, Per E

2009-10-01

The pro-inflammatory cytokines IL-1 beta, TNF-alpha and IL-6 are of great importance in the development of silica-induced lung damage and repair. In this study we investigated the role of IL-1 beta, TNF-alpha and COX2 in silica-induced regulation of IL-6 release and pneumocyte loss in various mono- and co-cultures of monocytes, pneumocytes and endothelial cells. All co-cultures with monocytes, and especially cultures including endothelial cells, showed an increase of silica-induced release of IL-6 compared to the respective monocultures. Treatment with the antagonist IL-1 ra strongly decreased IL-1 beta and IL-6 release in contact co-cultures of monocytes and pneumocytes. COX2 up-regulation by silica and IL-1 beta was eliminated by IL-1 ra. Inhibition of COX2 markedly reduced both IL-1 beta and IL-6 release. IL-1 ra was more effective than COX2-inhibition in reduction of IL-6, but not of IL-1 beta. Silica-induced pneumocyte loss was reduced by IL-1 beta, but this effect was not counteracted by the IL-1 receptor antagonist. Our findings suggest that silica-induced IL-6 release from pneumocytes is mainly mediated via IL-1 beta release from the monocytes, via both COX2-dependent and -independent pathways. Notably, COX2-derived mediators seem crucial for a positive feed-back regulation of IL-1 beta release from the monocytes. In contrast to silica-induced IL-6, the reduction in pneumocyte loss by IL-1 beta does not seem to be regulated through an IL-1R1-dependent mechanism.

Glutaminase-Deficient Mice Display Hippocampal Hypoactivity, Insensitivity to Pro-Psychotic Drugs and Potentiated Latent Inhibition: Relevance to Schizophrenia

PubMed Central

Gaisler-Salomon, Inna; Miller, Gretchen M; Chuhma, Nao; Lee, Sooyeon; Zhang, Hong; Ghoddoussi, Farhad; Lewandowski, Nicole; Fairhurst, Stephen; Wang, Yvonne; Conjard-Duplany, Agnès; Masson, Justine; Balsam, Peter; Hen, René; Arancio, Ottavio; Galloway, Matthew P; Moore, Holly M; Small, Scott A; Rayport, Stephen

2009-01-01

Dysregulated glutamatergic neurotransmission has been strongly implicated in the pathophysiology of schizophrenia (SCZ). Recently, presynaptic modulation of glutamate transmission has been shown to have therapeutic promise. We asked whether genetic knockdown of glutaminase (gene GLS1) to reduce glutamatergic transmission presynaptically by slowing the recycling of glutamine to glutamate, would produce a phenotype relevant to SCZ and its treatment. GLS1 heterozygous (GLS1 het) mice showed about a 50% global reduction in glutaminase activity, and a modest reduction in glutamate levels in brain regions relevant to SCZ pathophysiology, but displayed neither general behavioral abnormalities nor SCZ-associated phenotypes. Functional imaging, measuring regional cerebral blood volume, showed hippocampal hypometabolism mainly in the CA1 subregion and subiculum, the inverse of recent clinical imaging findings in prodromal and SCZ patients. GLS1 het mice were less sensitive to the behavioral stimulating effects of amphetamine, showed a reduction in amphetamine-induced striatal dopamine release and in ketamine-induced frontal cortical activation, suggesting that GLS1 het mice are resistant to the effects of these pro-psychotic challenges. Moreover, GLS1 het mice showed clozapine-like potentiation of latent inhibition, suggesting that reduction in glutaminase has antipsychotic-like properties. These observations provide further support for the pivotal role of altered glutamatergic synaptic transmission in the pathophysiology of SCZ, and suggest that presynaptic modulation of the glutamine–glutamate pathway through glutaminase inhibition may provide a new direction for the pharmacotherapy of SCZ. PMID:19516252

Glutaminase-deficient mice display hippocampal hypoactivity, insensitivity to pro-psychotic drugs and potentiated latent inhibition: relevance to schizophrenia.

PubMed

Gaisler-Salomon, Inna; Miller, Gretchen M; Chuhma, Nao; Lee, Sooyeon; Zhang, Hong; Ghoddoussi, Farhad; Lewandowski, Nicole; Fairhurst, Stephen; Wang, Yvonne; Conjard-Duplany, Agnès; Masson, Justine; Balsam, Peter; Hen, René; Arancio, Ottavio; Galloway, Matthew P; Moore, Holly M; Small, Scott A; Rayport, Stephen

2009-09-01

Dysregulated glutamatergic neurotransmission has been strongly implicated in the pathophysiology of schizophrenia (SCZ). Recently, presynaptic modulation of glutamate transmission has been shown to have therapeutic promise. We asked whether genetic knockdown of glutaminase (gene GLS1) to reduce glutamatergic transmission presynaptically by slowing the recycling of glutamine to glutamate, would produce a phenotype relevant to SCZ and its treatment. GLS1 heterozygous (GLS1 het) mice showed about a 50% global reduction in glutaminase activity, and a modest reduction in glutamate levels in brain regions relevant to SCZ pathophysiology, but displayed neither general behavioral abnormalities nor SCZ-associated phenotypes. Functional imaging, measuring regional cerebral blood volume, showed hippocampal hypometabolism mainly in the CA1 subregion and subiculum, the inverse of recent clinical imaging findings in prodromal and SCZ patients. GLS1 het mice were less sensitive to the behavioral stimulating effects of amphetamine, showed a reduction in amphetamine-induced striatal dopamine release and in ketamine-induced frontal cortical activation, suggesting that GLS1 het mice are resistant to the effects of these pro-psychotic challenges. Moreover, GLS1 het mice showed clozapine-like potentiation of latent inhibition, suggesting that reduction in glutaminase has antipsychotic-like properties. These observations provide further support for the pivotal role of altered glutamatergic synaptic transmission in the pathophysiology of SCZ, and suggest that presynaptic modulation of the glutamine-glutamate pathway through glutaminase inhibition may provide a new direction for the pharmacotherapy of SCZ.

Evidence for nucleotide receptor modulation of cross talk between MAP kinase and NF-kappa B signaling pathways in murine RAW 264.7 macrophages.

PubMed

Aga, Mini; Watters, Jyoti J; Pfeiffer, Zachary A; Wiepz, Gregory J; Sommer, Julie A; Bertics, Paul J

2004-04-01

Extracellular nucleotides such as ATP are present in abundance at sites of inflammation and tissue damage, and these agents exert a potent modulatory effect on macrophage/monocyte function via the nucleotide receptor P2X(7). In this regard, after exposure to bacterial LPS, P2X(7) activation augments expression of the inducible nitric oxide (NO) synthase and production of NO in macrophages. Because P2X(7) has been reported to stimulate certain members of the MAP kinase family (ERK1/2) and can enhance the DNA-binding activity of NF-kappa B, we tested the hypothesis that LPS and nucleotides regulate NF-kappa B-dependent inflammatory events via cross talk with MAPK-associated pathways. In this regard, the present studies revealed that cotreatment of macrophages with LPS and the P2X(7)-selective ligand 2'-3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) results in the cooperative activation of NF-kappa B DNA-binding activity and a sustained attenuation of levels of the NF-kappa B inhibitory protein I kappa B alpha. Interestingly, a persistent reduction in I kappa B alpha levels is also observed when the MEK1/2 inhibitor U0126 is coadministered with LPS, suggesting that components of the MEK/ERK pathway are involved in regulating I kappa B alpha protein expression and/or turnover. The observation that U0126 and BzATP exhibit overlapping actions with respect to LPS-induced changes in I kappa B alpha levels is supported by the finding that Ras activation, which is upstream of MEK/ERK activation, is reduced upon macrophage cotreatment with BzATP and LPS compared with the effects of BzATP treatment alone. These data are consistent with the concept that the Ras/MEK/ERK pathways are involved in regulating NF-kappa B/I kappa B-dependent inflammatory mediator production and suggest a previously unidentified mechanism by which nucleotides can modulate LPS-induced action via cross talk between NF-kappa B and Ras/MEK/MAPK-associated pathways.

Plasmonic tunnel junctions for single-molecule redox chemistry.

PubMed

de Nijs, Bart; Benz, Felix; Barrow, Steven J; Sigle, Daniel O; Chikkaraddy, Rohit; Palma, Aniello; Carnegie, Cloudy; Kamp, Marlous; Sundararaman, Ravishankar; Narang, Prineha; Scherman, Oren A; Baumberg, Jeremy J

2017-10-20

Nanoparticles attached just above a flat metallic surface can trap optical fields in the nanoscale gap. This enables local spectroscopy of a few molecules within each coupled plasmonic hotspot, with near thousand-fold enhancement of the incident fields. As a result of non-radiative relaxation pathways, the plasmons in such sub-nanometre cavities generate hot charge carriers, which can catalyse chemical reactions or induce redox processes in molecules located within the plasmonic hotspots. Here, surface-enhanced Raman spectroscopy allows us to track these hot-electron-induced chemical reduction processes in a series of different aromatic molecules. We demonstrate that by increasing the tunnelling barrier height and the dephasing strength, a transition from coherent to hopping electron transport occurs, enabling observation of redox processes in real time at the single-molecule level.

Chemical Forms of Selenium in the Metal-Resistant Bacterium Ralstonia metallidurans CH34 Exposed to Selenite and Selenate

PubMed Central

Sarret, Géraldine; Avoscan, Laure; Carrière, Marie; Collins, Richard; Geoffroy, Nicolas; Carrot, Francine; Covès, Jacques; Gouget, Barbara

2005-01-01

Ralstonia metallidurans CH34, a soil bacterium resistant to a variety of metals, is known to reduce selenite to intracellular granules of elemental selenium (Se0). We have studied the kinetics of selenite (SeIV) and selenate (SeVI) accumulation and used X-ray absorption spectroscopy to identify the accumulated form of selenate, as well as possible chemical intermediates during the transformation of these two oxyanions. When introduced during the lag phase, the presence of selenite increased the duration of this phase, as previously observed. Selenite introduction was followed by a period of slow uptake, during which the bacteria contained Se0 and alkyl selenide in equivalent proportions. This suggests that two reactions with similar kinetics take place: an assimilatory pathway leading to alkyl selenide and a slow detoxification pathway leading to Se0. Subsequently, selenite uptake strongly increased (up to 340 mg Se per g of proteins) and Se0 was the predominant transformation product, suggesting an activation of selenite transport and reduction systems after several hours of contact. Exposure to selenate did not induce an increase in the lag phase duration, and the bacteria accumulated approximately 25-fold less Se than when exposed to selenite. SeIV was detected as a transient species in the first 12 h after selenate introduction, Se0 also occurred as a minor species, and the major accumulated form was alkyl selenide. Thus, in the present experimental conditions, selenate mostly follows an assimilatory pathway and the reduction pathway is not activated upon selenate exposure. These results show that R. metallidurans CH34 may be suitable for the remediation of selenite-, but not selenate-, contaminated environments. PMID:15870319

Activated AMPK and prostaglandins are involved in the response to conjugated linoleic acid and are sufficient to cause lipid reductions in adipocytes.

PubMed

Jiang, Shan; Chen, Han; Wang, Zhigang; Riethoven, Jean-Jack; Xia, Yuannan; Miner, Jess; Fromm, Michael

2011-07-01

trans-10, cis-12 Conjugated linoleic acid (t10c12 CLA) reduces triglyceride levels in adipocytes. AMP-activated protein kinase (AMPK) and inflammation were recently demonstrated to be involved in the emerging pathways regulating this response. This study further investigated the role of AMPK and inflammation by testing the following hypotheses: (1) a moderate activation of AMPK and an inflammatory response are sufficient to reduce triglycerides, and (2) strong activation of AMPK is also sufficient. Experiments were performed by adding compounds that affect these pathways and by measuring their effects in 3T3-L1 adipocytes. A comparison of four AMPK activators (metformin, phenformin, TNF-α and t10c12 CLA) found a correlation between AMPK activity and triglyceride reduction. This correlation appeared to be modulated by the level of cyclo-oxygenase (COX)-2 mRNA produced. Inhibitors of the prostaglandin (PG) biosynthetic pathway interfered with t10c12 CLA's ability to reduce triglycerides. A combination of metformin and PGH2, or phenformin alone, efficiently reduced triglyceride levels in adipocytes. Microarray analysis indicated that the transcriptional responses to phenformin or t10c12 CLA were very similar, suggesting similar pathways were activated. 3T3-L1 fibroblasts were found to weakly induce the integrated stress response (ISR) in response to phenformin or t10c12 CLA and to respond robustly as they differentiated into adipocytes. This indicated that both chemicals required adipocytes at the same stage of differentiation to be competent for this response. These results support the above hypotheses and suggest compounds that moderately activate AMPK and increase PG levels or robustly activate AMPK in adipocytes may be beneficial for reducing adiposity. Copyright © 2011 Elsevier Inc. All rights reserved.

Neutrophils Promote Mycobacterial Trehalose Dimycolate-Induced Lung Inflammation via the Mincle Pathway

PubMed Central

Lee, Wook-Bin; Kang, Ji-Seon; Yan, Ji-Jing; Lee, Myeong Sup; Jeon, Bo-Young; Cho, Sang-Nae; Kim, Young-Joon

2012-01-01

Trehalose 6,6′-dimycolate (TDM), a cord factor of Mycobacterium tuberculosis (Mtb), is an important regulator of immune responses during Mtb infections. Macrophages recognize TDM through the Mincle receptor and initiate TDM-induced inflammatory responses, leading to lung granuloma formation. Although various immune cells are recruited to lung granulomas, the roles of other immune cells, especially during the initial process of TDM-induced inflammation, are not clear. In this study, Mincle signaling on neutrophils played an important role in TDM-induced lung inflammation by promoting adhesion and innate immune responses. Neutrophils were recruited during the early stage of lung inflammation following TDM-induced granuloma formation. Mincle expression on neutrophils was required for infiltration of TDM-challenged sites in a granuloma model induced by TDM-coated-beads. TDM-induced Mincle signaling on neutrophils increased cell adherence by enhancing F-actin polymerization and CD11b/CD18 surface expression. The TDM-induced effects were dependent on Src, Syk, and MAPK/ERK kinases (MEK). Moreover, coactivation of the Mincle and TLR2 pathways by TDM and Pam3CSK4 treatment synergistically induced CD11b/CD18 surface expression, reactive oxygen species, and TNFα production by neutrophils. These synergistically-enhanced immune responses correlated with the degree of Mincle expression on neutrophil surfaces. The physiological relevance of the Mincle-mediated anti-TDM immune response was confirmed by defective immune responses in Mincle−/− mice upon aerosol infections with Mtb. Mincle-mutant mice had higher inflammation levels and mycobacterial loads than WT mice. Neutrophil depletion with anti-Ly6G antibody caused a reduction in IL-6 and monocyte chemotactic protein-1 expression upon TDM treatment, and reduced levels of immune cell recruitment during the initial stage of infection. These findings suggest a new role of Mincle signaling on neutrophils during anti-mycobacterial responses. PMID:22496642

Flavanone silibinin treatment attenuates nitrogen mustard-induced toxic effects in mouse skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Anil K.; Tewari-Singh, Neera; Inturi, Swetha

Currently, there is no effective antidote to prevent skin injuries by sulfur mustard (SM) and nitrogen mustard (NM), which are vesicating agents with potential relevance to chemical warfare, terrorist attacks, or industrial/laboratory accidents. Our earlier report has demonstrated the therapeutic efficacy of silibinin, a natural flavanone, in reversing monofunctional alkylating SM analog 2-chloroethyl ethyl sulfide-induced toxic effects in mouse skin. To translate this effect to a bifunctional alkylating vesicant, herein, efficacy studies were carried out with NM. Topical application of silibinin (1 or 2 mg) 30 min after NM exposure on the dorsal skin of male SKH-1 hairless mice significantlymore » decreased NM-induced toxic lesions at 24, 72 or 120 h post-exposure. Specifically, silibinin treatment resulted in dose-dependent reduction of NM-induced increase in epidermal thickness, dead and denuded epidermis, parakeratosis and microvesication. Higher silibinin dose also caused a 79% and 51%reversal in NM-induced increases in myeloperoxidase activity and COX-2 levels, respectively. Furthermore, silibinin completely prevented NM-induced H2A.X phosphorylation, indicating reversal of DNA damage which could be an oxidative DNA damage as evidenced by high levels of 8-oxodG in NM-exposed mouse skin that was significantly reversed by silibinin. Together, these findings suggest that attenuation of NM-induced skin injury by silibinin is due to its effects on the pathways associated with DNA damage, inflammation, vesication and oxidative stress. In conclusion, results presented here support the optimization of silibinin as an effective treatment of skin injury by vesicants. - Highlights: • Silibinin treatment attenuated nitrogen mustard (NM)-induced skin injury. • Silibinin affects pathways associated with DNA damage, inflammation and vesication. • The efficacy of silibinin could also be associated with oxidative stress. • These results support testing and optimization of silibinin against SM-induced skin injury.« less

Mechanistic Explanation of the pH Dependence and Onset Potentials for Hydrocarbon Products from Electrochemical Reduction of CO on Cu (111)

DOE PAGES

Xiao, Hai; Cheng, Tao; Goddard, William A.; ...

2015-12-30

Energy and environmental concerns demand development of more efficient and selective electrodes for electrochemical reduction of CO 2 to form fuels and chemicals. Since Cu is the only pure metal exhibiting reduction to form hydrocarbon chemicals, we focus here on the Cu (111) electrode. We present a methodology for density functional theory calculations to obtain accurate onset electrochemical potentials with explicit constant electrochemical potential and pH effects using implicit solvation. We predict the atomistic mechanisms underlying electrochemical reduction of CO, finding that (1) at acidic pH, the C 1 pathway proceeds through COH to CHOH to form CH 4 whilemore » C 2 (C 3) pathways are kinetically blocked; (2) at neutral pH, the C 1 and C 2 (C 3) pathways share the COH common intermediate, where the branch to C-C coupling is realized by a novel CO-COH pathway; and (3) at high pH, early C-C coupling through adsorbed CO dimerization dominates, suppressing the C 1 pathways by kinetics, thereby boosting selectivity for multi-carbon products.« less

Descending antinociception induced by secondary somatosensory cortex stimulation in experimental neuropathy: role of the medullospinal serotonergic pathway

PubMed Central

Sagalajev, Boriss; Viisanen, Hanna; Wei, Hong

2017-01-01

Stimulation of the secondary somatosensory cortex (S2) has attenuated pain in humans and inflammatory nociception in animals. Here we studied S2 stimulation-induced antinociception and its underlying mechanisms in an experimental animal model of neuropathy induced by spinal nerve ligation (SNL). Effect of S2 stimulation on heat-evoked limb withdrawal latency was assessed in lightly anesthetized rats that were divided into three groups based on prior surgery and monofilament testing before induction of anesthesia: 1) sham-operated group and 2) hypersensitive and 3) nonhypersensitive (mechanically) SNL groups. In a group of hypersensitive SNL animals, a 5-HT1A receptor agonist was microinjected into the rostroventromedial medulla (RVM) to assess whether autoinhibition of serotonergic cell bodies blocks antinociception. Additionally, effect of S2 stimulation on pronociceptive ON-cells and antinociceptive OFF-cells in the RVM or nociceptive spinal wide dynamic range (WDR) neurons were assessed in anesthetized hypersensitive SNL animals. S2 stimulation induced antinociception in hypersensitive but not in nonhypersensitive SNL or sham-operated animals. Antinociception was prevented by a 5-HT1A receptor agonist in the RVM. Antinociception was associated with decreased duration of heat-evoked response in RVM ON-cells. In spinal WDR neurons, heat-evoked discharge was delayed by S2 stimulation, and this antinociceptive effect was prevented by blocking spinal 5-HT1A receptors. The results indicate that S2 stimulation suppresses nociception in SNL animals if SNL is associated with tactile allodynia-like hypersensitivity. In hypersensitive SNL animals, S2 stimulation induces antinociception mediated by medullospinal serotonergic pathways acting on the spinal 5-HT1A receptor, and partly through reduction of the RVM ON-cell discharge. NEW & NOTEWORTHY Stimulation of S2 cortex, but not that of an adjacent cortical area, induced descending heat antinociception in rats with the spinal nerve ligation-induced model of neuropathy. Antinociception was bilateral, and it involved suppression of pronociceptive medullary cells and activation of serotonergic pathways that act on the spinal 5-HT1A receptor. S2 stimulation failed to induce descending antinociceptive effect in sham-operated controls or in nerve-ligated animals that had not developed mechanical hypersensitivity. PMID:28053243

Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate

PubMed Central

Thorup, Casper; Schramm, Andreas

2017-01-01

ABSTRACT This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus. Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase. PMID:28720728

4-O-Methylhonokiol Protects HaCaT Cells from TGF-β1-Induced Cell Cycle Arrest by Regulating Canonical and Non-Canonical Pathways of TGF-β Signaling.

PubMed

Kim, Sang-Cheol; Kang, Jung-Il; Hyun, Jin-Won; Kang, Ji-Hoon; Koh, Young-Sang; Kim, Young-Heui; Kim, Ki-Ho; Ko, Ji-Hee; Yoo, Eun-Sook; Kang, Hee-Kyoung

2017-07-01

4- O -methylhonokiol, a neolignan compound from Magnolia Officinalis , has been reported to have various biological activities including hair growth promoting effect. However, although transforming growth factor-β (TGF-β) signal pathway has an essential role in the regression induction of hair growth, the effect of 4- O -methylhonokiol on the TGF-β signal pathway has not yet been elucidated. We thus examined the effect of 4- O -methylhonokiol on TGF-β-induced canonical and noncanonical pathways in HaCaT human keratinocytes. When HaCaT cells were pretreated with 4- O -methylhonokiol, TGF-β1-induced G1/G0 phase arrest and TGF-β1-induced p21 expression were decreased. Moreover, 4- O -methylhonokiol inhibited nuclear translocation of Smad2/3, Smad4 and Sp1 in TGF-β1-induced canonical pathway. We observed that ERK phosphorylation by TGF-β1 was significantly attenuated by treatment with 4- O -methylhonokiol. 4- O -methylhonokiol inhibited TGF-β1-induced reactive oxygen species (ROS) production and reduced the increase of NADPH oxidase 4 (NOX4) mRNA level in TGF-β1-induced noncanonical pathway. These results indicate that 4- O -methylhonokiol could inhibit TGF-β1-induced cell cycle arrest through inhibition of canonical and noncanonical pathways in human keratinocyte HaCaT cell and that 4- O -methylhonokiol might have protective action on TGF-β1-induced cell cycle arrest.

Phenylbutyrate interferes with the Fanconi anemia and BRCA pathway and sensitizes head and neck cancer cells to cisplatin

PubMed Central

Burkitt, Kyunghee; Ljungman, Mats

2008-01-01

Background Cisplatin has been widely used to treat head and neck cancer. One of the clinical limitations with this treatment, however, is that tumors that are initially responsive to cisplatin later acquire resistance. We have recently shown that a subset of head and neck cancer cell lines has a defective Fanconi anemia DNA damage response pathway and this defect correlates to cisplatin sensitivity. We have also shown that the histone deacetylase inhibitor phenylbutyrate sensitize human cells to cisplatin. In this study we explored whether phenylbutyrate may sensitize head and neck cancer cells by interfering with the Fanconi anemia pathway. Results We found that the phenylbutyrate sensitizes head and neck cancer cell lines to cisplatin. This sensitization by phenylbutyrate correlated to a significant decrease in the formation of cisplatin-induced FANCD2 nuclear foci, which is a functional read out of the Fanconi anemia and BRCA (FA/BRCA) pathway. This abrogation of the FA/BRCA pathway by phenylbutyrate was not due to loss of FANCD2 monoubiquitylation but rather correlated to a phenylbutyrate-mediated reduction in the expression of the BRCA1 protein. Furthermore, we found that cancer cells defective in the FA pathway were also sensitized to cisplatin by phenylbutyrate suggesting that phenylbutyrate targets additional pathways. Conclusion The results from this study suggest that phenylbutyrate may have therapeutic utility as a cisplatin sensitizer in head and neck cancer by inhibiting the FA/BRCA pathway through the down regulation of BRCA1 as well as by an FA/BRCA-independent mechanism. PMID:18325101

Tomographic analysis of reactive flow induced pore structure changes in column experiments

NASA Astrophysics Data System (ADS)

Cai, Rong; Lindquist, W. Brent; Um, Wooyong; Jones, Keith W.

2009-09-01

We utilize synchrotron X-ray computed micro-tomography to capture and quantify snapshots in time of dissolution and secondary precipitation in the microstructure of Hanford sediments exposed to simulated caustic waste in flow-column experiments. The experiment is complicated somewhat as logistics dictated that the column spent significant amounts of time in a sealed state (acting as a batch reactor). Changes accompanying a net reduction in porosity of 4% were quantified including: (1) a 25% net decrease in pores resulting from a 38% loss in the number of pores <10-4mm in volume and a 13% increase in the number of pores of larger size; and (2) a 38% decrease in the number of throats. The loss of throats resulted in decreased coordination number for pores of all sizes and significant reduction in the number of pore pathways.

Different signal pathways regulate IL-1β-induced mature and primary miRNA-146a expression in human alveolar epithelial cells.

PubMed

Jiang, Xiaoying

2014-09-01

It was known that IL-1β-induced rapid expression of miR-146a, which regulated the secretion of inflammatory chemokines in human A549 alveolar epithelial cells. However, little is known about the level of primary miR-146a and the downstream biogenesis of miR-146a in A549 cells. We examined the levels of primary miR-146a and mature miR-146a in A549 cells following treatment with pharmacological inhibitors of IKK-2 (TPCA-1), MEK-1/2 (PD098059), JNK-1/2 (SP600125), p38 MAPK (SB 203580) and PI-3k (LY294002). Our studies showed that exposure to PD98059, TPCA-1 and LY294002 resulted in a dose-dependent reduction in the expression of mature miR-146a while the primary miR-146a expression was not changed by any inhibitor. Western blot showed that IL-1β induced an increase of TRBP at 30 min, following by an extended expression at 24 h compared to the non-IL-1β controls in A549 cells. In conclusion, our studies indicated that miR-146a expression in alveolar epithelial cells was regulated at the post-transcriptional level via a MEK-1/2 and IKK2 pathway, and also for the first time via PI-3k pathway. The longer expression of TRBP following stimulation with IL-1β suggests that TRBP might play a role in the process of regulating the processing of primary miR-146a to mature miR-146a in human alveolar epithelial cells.

Neonatal exposure to estradiol valerate increases dopamine content in nigrostriatal pathway during adulthood in the rat.

PubMed

Cruz, G; Riquelme, R; Espinosa, P; Jara, P; Dagnino-Subiabre, A; Renard, G M; Sotomayor-Zárate, R

2014-05-01

Research in programming has focused in the study of stimuli that affect sensitive periods of development such as prenatal and neonatal stage. We previously showed that exposure to estradiol valerate to female rats during the first 12 h of life increased catecholamine content in ventromedial-arcuatus hypothalamus of the adult rat. However, changes in others dopaminergic circuits have not been studied. The purpose of this work was to determine the neurotransmitters changes induced by neonatal estradiol valerate (0.1 mg/50 μl s. c. per rat) administration on nigrostriatal pathway of adult female rats. Sesame oil (50 μl s. c. per rat) was administered in a control parallel group. EV-1 adult rats presented effective markers of long-term estrogenization as decreased serum levels of progesterone and a reduction in the size of estrogen-sensitive organs. In the brain, neonatal estradiol valerate administration led to a significant increase in dopamine content in striatum, substantia nigra and ventral tegmental area. With respect to the contents of dopamine metabolites, only 3-methoxytyramine content increased in substantia nigra and ventral tegmental area. In addition, the content of noradrenaline increased only in striatum. Interestingly, estrogenized rats lacked locomotor activity induced by acute dose of amphetamine (1 mg/kg i. p.). Altogether, these results show that neonatal exposure to estradiol valerate permanently modified the content of monoamine neurotransmitters in nigrostriatal pathway and amphetamine-induced locomotor activity of adult female rats. This might imply that estrogenized rats could have changes in the expression of key proteins in dopaminergic regulation, as tyrosine hydroxylase and dopamine transporter. © Georg Thieme Verlag KG Stuttgart · New York.

Redox regulation of energy transfer efficiency in antennas of green photosynthetic bacteria

NASA Technical Reports Server (NTRS)

Blankenship, R. E.; Cheng, P.; Causgrove, T. P.; Brune, D. C.; Wang, J.

1993-01-01

The efficiency of energy transfer from the peripheral chlorosome antenna structure to the membrane-bound antenna in green sulfur bacteria depends strongly on the redox potential of the medium. The fluorescence spectra and lifetimes indicate that efficient quenching pathways are induced in the chlorosome at high redox potential. The midpoint redox potential for the induction of this effect in isolated chlorosomes from Chlorobium vibrioforme is -146 mV at pH 7 (vs the normal hydrogen electrode), and the observed midpoint potential (n = 1) decreases by 60 mV per pH unit over the pH range 7-10. Extraction of isolated chlorosomes with hexane has little effect on the redox-induced quenching, indicating that the component(s) responsible for this effect are bound and not readily extractable. We have purified and partially characterized the trimeric water-soluble bacteriochlorophyll a-containing protein from the thermophilic green sulfur bacterium Chlorobium tepidum. This protein is located between the chlorosome and the membrane. Fluorescence spectra of the purified protein indicate that it also contains groups that quench excitations at high redox potential. The results indicate that the energy transfer pathway in green sulfur bacteria is regulated by redox potential. This regulation appears to operate in at least two distinct places in the energy transfer pathway, the oligomeric pigments in the interior of the chlorosome and in the bacteriochlorophyll a protein. The regulatory effect may serve to protect the cell against superoxide-induced damage when oxygen is present. By quenching excitations before they reach the reaction center, reduction and subsequent autooxidation of the low potential electron acceptors found in these organisms is avoided.

Metabolic effect of TAp63α: enhanced glycolysis and pentose phosphate pathway, resulting in increased antioxidant defense

PubMed Central

D'Alessandro, Angelo; Amelio, Ivano; Berkers, Celia R.; Antonov, Alexey; Vousden, Karen H.; Melino, Gerry; Zolla, Lello

2014-01-01

TAp63α is a member of the p53 family, which plays a central role in epithelial cancers. Recently, a role has emerged for p53 family members in cancer metabolic modulation. In order to assess whether TAp63α plays a role in cancer metabolism, we exploited p53-null osteosarcoma Tet-On Saos-2 cells, in which the expression of TAp63α was dependent on doxycycline supplementation to the medium. Metabolomics labeling experiments were performed by incubating the cells in 13C-glucose or 13C15N-glutamine-labeled culture media, as to monitor metabolic fluxes upon induced expression of TAp63α. Induced expression of TAp63α resulted in cell cycle arrest at the G1 phase. From a metabolic standpoint, expression of Tap63α promoted glycolysis and the pentose phosphate pathway, which was uncoupled from nucleotide biosynthesis, albeit prevented oxidative stress in the form of oxidized glutathione. Double 13C-glucose and 13C15N-glutamine metabolic labeling confirmed that induced expression of TAp63α corresponded to a decreased flux of pyruvate to the Krebs cycle and decreased utilization of glutamine for catabolic purposes in the TCA cycle. Results were not conclusive in relation to anabolic utilization of labeled glutamine, since it is unclear to what extent the observed minor TAp63α-dependent increases of glutamine-derived labeling in palmitate could be tied to increased rates of reductive carboxylation and de novo synthesis of fatty acids. Finally, bioinformatics elaborations highlighted a link between patient survival rates and the co-expression of p63 and rate limiting enzymes of the pentose phosphate pathway, G6PD and PGD. PMID:25229745

Hydroquinone induces TK6 cell growth arrest and apoptosis through PARP-1/p53 regulatory pathway.

PubMed

Luo, Hao; Liang, Hairong; Chen, Jiajia; Xu, Yongchun; Chen, Yuting; Xu, Longmei; Yun, Lin; Liu, Jiaxian; Yang, Hui; Liu, Linhua; Peng, Jianming; Liu, Zhidong; Tang, Lin; Chen, Wen; Tang, Huanwen

2017-09-01

Hydroquinone (HQ), one of the most important metabolites derived from benzene, induces cell cycle arrest and apoptosis. Poly(ADP-ribose) polymerase-1 (PARP-1) participates in various biological processes, including DNA repair and cell cycle regulation. To explore whether PARP-1 regulatory pathway mediated HQ-induced cell cycle arrest and apoptosis, we assessed the effect of PARP-1 suppression on induction of apoptosis analyzed by FACSCalibur flow cytometer in PARP-1 deficientTK6 cells (TK6-shPARP-1). We observed an increase in the fraction of cells in G1 phase by 7.6% and increased apoptosis by 4.5% in PARP-1-deficient TK6 cells (TK6-shPARP-1) compared to those negative control cells (TK6-shNC cells) in response to HQ treatment. Furthermore, HQ might activate the extrinsic pathways of apoptosis via up-regulation of Fas expression, followed by caspase-3 activation, apoptotic body, and sub G1 accumulation. Enhanced p53 expression was observed in TK6-shPARP-1 cells than in TK6-shNC cells after HQ treatment. In contrast, Fas expression was lower in TK6-shPARP-1 cells than in TK6-shNC cells. Therefore, we conclude that HQ may activate apoptotic signals via Fas up-regulation and p53-mediated apoptosis in TK6-shNC cells. The reduction of PARP-1 expression further intensified up-regulation of p53 in TK6-shPARP-1 cells, resulting in an increased G1→S phase cell arrest and apoptosis in TK6-shPARP-1 cells compared to TK6-shNC cells. © 2017 Wiley Periodicals, Inc.

Peptidoglycan Recognition Protein S2 From Silkworm Integument: Characterization, Microbe-Induced Expression, and Involvement in the Immune-Deficiency Pathway

PubMed Central

Yang, Jie; Wang, Xiaonan; Tang, Shunming; Shen, Zhongyuan; Wu, Jinmei

2015-01-01

Peptidoglycan recognition protein (PGRP) binds specifically to peptidoglycan and plays an important role as a pattern recognition receptor in the innate immunity of insects. The cDNA of a short-type PGRP, an open reading frame of 588 bp encoding a polypeptide of 196 amino acids, was cloned from Bombyx mori. A phylogenetic tree was constructed, and the results showed that BmPGRP-S2 was most similar to Drosophila melanogaster PGRP (DmPGRP-SA). The induced expression profile of BmPGRP-S2 in healthy Escherichia coli- and Bacillus subtilis-challenged B. mori was measured using semiquantitative reverse transcriptase polymerase chain reaction analysis. The expression of BmPGRP-S2 was upregulated at 24 h by E. coli and Ba. subtilis challenge. In addition, in the integument of B. mori, RNAi knockdown of BmPGRP-S2 caused an obvious reduction in the transcription expression of the transcription factor Relish and in antibacterial effector genes Attacin, Gloverin, and Moricin. The results indicated that BmPGRP-S2 participates in the signal transduction pathway of B. mori. PMID:25797797

Vitamin D enhances omega-3 polyunsaturated fatty acids-induced apoptosis in breast cancer cells.

PubMed

Yang, Jing; Zhu, Shenglong; Lin, Guangxiao; Song, Ci; He, Zhao

2017-08-01

Breast cancer is a leading type of cancer in women and generally classified into three subtypes of ER + /PR + , HER2 + and triple negative. Both omega-3 polyunsaturated fatty acids and vitamin D 3 play positive role in the reduction of breast cancer incidence. However, whether combination of omega-3 polyunsaturated fatty acids and vitamin D 3 has stronger protective effect on breast carcinogenesis still remains unknown. In this study, we show that the combination of ω-3 free fatty acids (ω-3 FFAs) and 1α, 25-dihydroxy-vitamin D 3 (VD 3 ) dramatically enhances cell apoptosis among three subtypes of breast cancer cell lines. Bcl-2 and total PARP protein levels are decreased in combined treatment MCF-7 and SK-BR-3 cells. Caspase signals play a vital role in cell apoptosis induced by combination. Moreover, Raf-MAPK signaling pathway is involved in the apoptosis induction by combination of ω-3 FFAs+VD 3 . These results demonstrate that the induction of cell apoptosis by combined treatment is dependent on different signaling pathways in three subtypes of breast cancer cell lines. © 2017 International Federation for Cell Biology.

Interaction of renin-angiotensin system and adenosine monophosphate-activated protein kinase signaling pathway in renal carcinogenesis of uninephrectomized rats.

PubMed

Yang, Ke-Ke; Sui, Yi; Zhou, Hui-Rong; Zhao, Hai-Lu

2017-05-01

Renin-angiotensin system and adenosine monophosphate-activated protein kinase signaling pathway both play important roles in carcinogenesis, but the interplay of renin-angiotensin system and adenosine monophosphate-activated protein kinase in carcinogenesis is not clear. In this study, we researched the interaction of renin-angiotensin system and adenosine monophosphate-activated protein kinase in renal carcinogenesis of uninephrectomized rats. A total of 96 rats were stratified into four groups: sham, uninephrectomized, and uninephrectomized treated with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Renal adenosine monophosphate-activated protein kinase and its downstream molecule acetyl coenzyme A carboxylase were detected by immunohistochemistry and western blot at 10 months after uninephrectomy. Meanwhile, we examined renal carcinogenesis by histological transformation and expressions of Ki67 and mutant p53. During the study, fasting lipid profiles were detected dynamically at 3, 6, 8, and 10 months. The results indicated that adenosine monophosphate-activated protein kinase expression in uninephrectomized rats showed 36.8% reduction by immunohistochemistry and 89.73% reduction by western blot. Inversely, acetyl coenzyme A carboxylase expression increased 83.3% and 19.07% in parallel to hyperlipidemia at 6, 8, and 10 months. The histopathology of carcinogenesis in remnant kidneys was manifested by atypical proliferation and carcinoma in situ, as well as increased expressions of Ki67 and mutant p53. Intervention with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker significantly prevented the inhibition of adenosine monophosphate-activated protein kinase signaling pathway and renal carcinogenesis in uninephrectomized rats. In conclusion, the novel findings suggest that uninephrectomy-induced disturbance in adenosine monophosphate-activated protein kinase signaling pathway resulted in hyperlipidemia and carcinogenesis in tubular epithelial cells, which may be largely attenuated by renin-angiotensin system blockade, implying the interaction of renin-angiotensin system and adenosine monophosphate-activated protein kinase signaling pathway in renal carcinogenesis of uninephrectomized rats.

A shortcut to wide-ranging biological actions of dietary polyphenols: modulation of the nitrate-nitrite-nitric oxide pathway in the gut.

PubMed

Rocha, Bárbara S; Nunes, Carla; Pereira, Cassilda; Barbosa, Rui M; Laranjinha, João

2014-08-01

Dietary polyphenols are complex, natural compounds with recognized health benefits. Initially attractive to the biomedical area due to their in vitro antioxidant properties, the biological implications of polyphenols are now known to be far from their acute ability to scavenge free radicals but rather to modulate redox signaling pathways. Actually, it is now recognized that dietary polyphenols are extensively metabolized in vivo and that the chemical, biophysical and biological properties of their metabolites are, in most cases, quite different from the ones of the parent molecules. Hence, the study of the metabolic, absorptive and signaling pathways of both phenolics and derivatives has become a major issue. In this paper we propose a short-cut for the systemic effects of polyphenols in connection with nitric oxide (˙NO) biology. This free radical is a ubiquitous signaling molecule with pivotal functions in vivo. It is produced through an enzymatic pathway and also through the reduction of dietary nitrate and nitrite in the human stomach. At acidic gastric pH, dietary polyphenols, in the form they are conveyed in foods and at high concentration, not only promote nitrite reduction to ˙NO but also embark in a complex network of chemical reactions to produce higher nitrogen oxides with signaling functions, namely by inducing post-translational modifications. Modified endogenous molecules, such as nitrated proteins and lipids, acquire important physiological functions. Thus, local and systemic effects of ˙NO such as modulation of vascular tone, mucus production in the gut and protection against ischemia-reperfusion injury are, in this sense, triggered by dietary polyphenols. Evidence to support the signaling and biological effects of polyphenols by modulation of the nitrate-nitrite-NO pathway will be herein provided and discussed. General actions of polyphenols encompassing absorption and metabolism in the intestine/liver are short-cut via the production of diffusible species in the stomach that have not only a local but also a general impact.

Acid sphingomyelinase deficiency in Western diet-fed mice protects against adipocyte hypertrophy and diet-induced liver steatosis.

PubMed

Sydor, Svenja; Sowa, Jan-Peter; Megger, Dominik A; Schlattjan, Martin; Jafoui, Sami; Wingerter, Lena; Carpinteiro, Alexander; Baba, Hideo A; Bechmann, Lars P; Sitek, Barbara; Gerken, Guido; Gulbins, Erich; Canbay, Ali

2017-05-01

Alterations in sphingolipid and ceramide metabolism have been associated with various diseases, including nonalcoholic fatty liver disease (NAFLD). Acid sphingomyelinase (ASM) converts the membrane lipid sphingomyelin to ceramide, thereby affecting membrane composition and domain formation. We investigated the ways in which the Asm knockout (Smpd1 -/- ) genotype affects diet-induced NAFLD. Smpd1 -/- mice and wild type controls were fed either a standard or Western diet (WD) for 6 weeks. Liver and adipose tissue morphology and mRNA expression were assessed. Quantitative proteome analysis of liver tissue was performed. Expression of selected genes was quantified in adipose and liver tissue of obese NAFLD patients. Although Smpd1 -/- mice exhibited basal steatosis with normal chow, no aggravation of NAFLD-type injury was observed with a Western diet. This protective effect was associated with the absence of adipocyte hypertrophy and the increased expression of genes associated with brown adipocyte differentiation. In white adipose tissue from obese patients with NAFLD, no expression of these genes was detectable. To further elucidate which pathways in liver tissue may be affected by Smpd1 -/- , we performed an unbiased proteome analysis. Protein expression in WD-fed Smpd1 -/- mice indicated a reduction in Rictor (mTORC2) activity; this reduction was confirmed by diminished Akt phosphorylation and altered mRNA expression of Rictor target genes. These findings indicate that the protective effect of Asm deficiency on diet-induced steatosis is conferred by alterations in adipocyte morphology and lipid metabolism and by reductions in Rictor activation.

Increased sensitivity to apoptosis induced by methotrexate is mediated by Jun N-terminal kinase

PubMed Central

Spurlock, Charles F.; Aune, Zachary T.; Tossberg, John T.; Collins, Patrick L.; Aune, Jessica P.; Huston, Joseph W.; Crooke, Philip S.; Olsen, Nancy J.; Aune, Thomas M.

2011-01-01

Objective Low-dose methotrexate [MTX] is an effective therapy for rheumatoid arthritis yet its mechanism of action is incompletely understood. Here, we explored induction of apoptosis by MTX. Methods We employed flow cytometry to assess changes in levels of intracellular proteins, reactive oxygen species [ROS], and apoptosis.Quantitative polymerase chain reaction was usedtoassess changes in transcript levels of select target genes in response to MTX. Results MTX does not directly induce apoptosis but rather ‘primes’ cells for markedly increased sensitivity to apoptosis via either mitochondrial or death receptor pathways by a Jun N-terminal kinase [JNK]-dependent mechanism. Increased sensitivity to apoptosis is mediated, at least in part, by MTX-dependent production of reactive oxygen species, JNK activation and JNK-dependent induction of genes whose protein products promote apoptosis. Supplementation with tetrahydrobiopterin blocks these methotrexate-induced effects. Subjects with rheumatoid arthritis on low-dose MTX therapy express elevated levels of the JNK-target gene, JUN. Conclusions Our results support a model whereby methotrexate inhibits reduction of dihydrobiopterin to tetrahydrobiopterin resulting in increased production of ROS, increased JNK activity and increased sensitivity to apoptosis. The finding of increased JUN levels in subjects with RA taking low-dose MTX supports the notion that this pathway is activated by MTX, in vivo, and may contribute to efficacy of MTX in inflammatory disease. PMID:21618198

EPA blocks TNF-α-induced inhibition of sugar uptake in Caco-2 cells via GPR120 and AMPK.

PubMed

Castilla-Madrigal, Rosa; Barrenetxe, Jaione; Moreno-Aliaga, María J; Lostao, María Pilar

2018-03-01

The aim of the present work was to investigate in Caco-2 cells whether eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, could block the inhibitory effect of tumor necrosis factor-α (TNF-α) on sugar transport, and identify the intracellular signaling pathways involved. After pre-incubation of the Caco-2 cells with TNF-α and EPA for 1 hr, EPA prevented the inhibitory effect of the cytokine on α-methyl-d-glucose (αMG) uptake (15 min) and on SGLT1 expression at the brush border membrane, measured by Western blot. The ERK1/2 inhibitor PD98059 and the AMPK activator AICAR also prevented the inhibitory effect of TNF-α on both αMG uptake and SGLT1 expression. Interestingly, the AMPK inhibitor, Compound C, abolished the ability of EPA to prevent TNF-α-induced reduction of sugar uptake and transporter expression. The GPR120 antagonist, AH7614, also blocked the preventive effect of EPA on TNF-α-induced decrease of αMG uptake and AMPK phosphorylation. In summary, TNF-α inhibits αMG uptake by decreasing SGLT1 expression in the brush border membrane through the activation of ERK1/2 pathway. EPA prevents the inhibitory effect of TNF-α through the involvement of GPR120 and AMPK activation. © 2017 Wiley Periodicals, Inc.

Selective endosomal microautophagy is starvation-inducible in Drosophila.

PubMed

Mukherjee, Anindita; Patel, Bindi; Koga, Hiroshi; Cuervo, Ana Maria; Jenny, Andreas

2016-11-01

Autophagy delivers cytosolic components to lysosomes for degradation and is thus essential for cellular homeostasis and to cope with different stressors. As such, autophagy counteracts various human diseases and its reduction leads to aging-like phenotypes. Macroautophagy (MA) can selectively degrade organelles or aggregated proteins, whereas selective degradation of single proteins has only been described for chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI). These 2 autophagic pathways are specific for proteins containing KFERQ-related targeting motifs. Using a KFERQ-tagged fluorescent biosensor, we have identified an eMI-like pathway in Drosophila melanogaster. We show that this biosensor localizes to late endosomes and lysosomes upon prolonged starvation in a KFERQ- and Hsc70-4- dependent manner. Furthermore, fly eMI requires endosomal multivesicular body formation mediated by ESCRT complex components. Importantly, induction of Drosophila eMI requires longer starvation than the induction of MA and is independent of the critical MA genes atg5, atg7, and atg12. Furthermore, inhibition of Tor signaling induces eMI in flies under nutrient rich conditions, and, as eMI in Drosophila also requires atg1 and atg13, our data suggest that these genes may have a novel, additional role in regulating eMI in flies. Overall, our data provide the first evidence for a novel, starvation-inducible, catabolic process resembling endosomal microautophagy in the Drosophila fat body.

Epidermal Growth Factor Receptor Inhibition with Erlotinib Partially Prevents Cisplatin-Induced Nephrotoxicity in Rats

PubMed Central

Matsumoto, Kei; Shindo-Hirai, Yuki; Kuno, Yoshihiro; Yamamoto, Yasutaka; Suzuki, Taihei; Saito, Tomohiro; Iseri, Ken; Shibata, Takanori

2014-01-01

The effects of blocking the epidermal growth factor receptor (EGFR) in acute kidney injury (AKI) are controversial. Here we investigated the renoprotective effect of erlotinib, a selective tyrosine kinase inhibitor that can block EGFR activity, on cisplatin (CP)-induced AKI. Groups of animals were given either erlotinib or vehicle from one day before up to Day 3 following induction of CP- nephrotoxicity (CP-N). In addition, we analyzed the effects of erlotinib on signaling pathways involved in CP-N by using human renal proximal tubular cells (HK-2). Compared to controls, rats treated with erlotinib exhibited significant improvement of renal function and attenuation of tubulointerstitial injury, and reduced the number of apoptotic and proliferating cells. Erlotinib-treated rats had a significant reduction of renal cortical mRNA for profibrogenic genes. The Bax/Bcl-2 mRNA and protein ratios were significantly reduced by erlotinib treatment. In vitro, we observed that erlotinib significantly reduced the phosphorylation of MEK1 and Akt, processes that were induced by CP in HK-2. Taken together, these data indicate that erlotinib has renoprotective properties that are likely mediated through decreases in the apoptosis and proliferation of tubular cells, effects that reflect inhibition of downstream signaling pathways of EGFR. These results suggest that erlotinib may be useful for preventing AKI in patients receiving CP chemotherapy. PMID:25390346

The Protective Effect of Apigenin on Myocardial Injury in Diabetic Rats mediating Activation of the PPAR-γ Pathway.

PubMed

Mahajan, Umesh B; Chandrayan, Govind; Patil, Chandragouda R; Arya, Dharamvir Singh; Suchal, Kapil; Agrawal, Yogeeta O; Ojha, Shreesh; Goyal, Sameer N

2017-04-04

We substantiated the role of peroxisome proliferator-activated receptor-γ (PPAR-γ) activation in the protective effect of apigenin against the myocardial infarction (MI) in diabetic rats. Diabetes was induced by intraperitoneal administration of a single dose of streptozotocin (55 mg/kg). The study groups included diabetic rats receiving vehicle, apigenin (75 mg/kg/day, orally), GW9662 (1 mg/kg/day, intraperitoneally), and a combination of apigenin and GW9662 for 14 days. The MI was induced in all the study groups except the diabetic control group by subcutaneous injection of 100 mg/kg/day of isoproterenol on the two terminal days. The diabetes and isoproterenol-induced MI was evident as a reduction in the maximal positive and negative rate of developed left ventricular pressure and an increase in the left ventricular end-diastolic pressure. The activities of creatine kinase on myocardial bundle (CK-MB) and lactate dehydrogenase (LDH) were also reduced. Apigenin treatment prevented the hemodynamic perturbations, restored the left ventricular function and reinstated a balanced redox status. It protected rats against an MI by attenuating myonecrosis, edema, cell death, and oxidative stress. GW9662, a PPAR-γ antagonist reversed the myocardial protection conferred by apigenin. Further, an increase in the PPAR-γ expression in the myocardium of the rats receiving apigenin reinforces the role of PPAR-γ pathway activation in the cardioprotective effects of apigenin.

Neuroprotection by baicalein in ischemic brain injury involves PTEN/AKT pathway.

PubMed

Liu, Chao; Wu, Jiliang; Xu, Kui; Cai, Fei; Gu, Jun; Ma, Liqun; Chen, Jianguo

2010-03-01

Recently more evidences support baicalein (Bai) is neuroprotective in models of ischemic stroke. This study was conducted to determine the molecular mechanisms involved in this effect. Either permanent or transient (2 h) middle cerebral artery occlusion (MCAO) was induced in rats in this study. Permanent MCAO led to larger infarct volumes in contrast to transient MCAO. Only in transient MCAO, Bai administration significantly reduced infarct size. Baicalein also markedly reduced apoptosis in the penumbra of transient MCAO rats. Additionally, oxygen and glucose deprivation (OGD) was used to mimic ischemic insult in primary cultured cortical neurons. A rapid increase in the intracellular reactive oxygen species level and nitrotyrosine formation induced by OGD was counteracted by Bai, which is parallel with attenuated cell injury. The reduction of phosphorylation Akt and glycogen synthase kinase-3beta (GSK3beta) induced by OGD was restored by Bai, which was associated with preserved levels of phosphorylation of PTEN, the phophatase that negatively regulates Akt. As a consequence, Bcl-2/Bcl-xL-associated death protein phosphorylation was increased and the protein level of Bcl-2 in motochondria was maintained, which subsequently antagonize cytochrome c released in cytosol. LY294002 blocked the increase in phospho-AKT evoked by Bai and abolished the associated protective effect. Together, these findings provide evidence that Bai protects neurons against ischemia injury and this neuroprotective effect involves PI3K/Akt and PTEN pathway.

Enhancement of Protective Effects of Radix Scutellariae on UVB-induced Photo Damage in Human HaCaT Keratinocytes.

PubMed

Wang, Yu-Shuai; Cho, Jin-Gyeong; Hwang, Eun-Son; Yang, Jung-Eun; Gao, Wei; Fang, Min-Zhe; Zheng, Sheng-Dao; Yi, Tae-Hoo

2018-04-01

Radix Scutellariae (RS) has long been used in the treatment of inflammatory and allergic diseases. Its main flavonoids, baicalin (BG) and wogonoside (WG), can be hydrolyzed into their corresponding aglycones, baicalein (B) and wogonin (W). In this study, we developed a safe and effective method of transforming these glycosides using Peclyve PR. The transformation rate of BG and WG reached 98.5 and 98.1%, respectively, with 10% enzyme at 40 °C for 60 h. Furthermore, we compared the anti-photoaging activity of RS before and after enzyme treatment, as well as their respective main components, in UVB-irradiated HaCaT cells. Results found that enzyme-treated RS (ERS) appeared to be much better at preventing UVB-induced photoaging than RS. ERS significantly inhibited the upregulation of matrix metalloproteinase-1 and IL-6 caused by UVB radiation by inactivating the MAPK/AP-1 and NF-κB/IκB-α signaling pathways. ERS treatment also recovered UVB-induced reduction of procollagen type I by activating the TGF-β/Smad pathway. In addition, ERS exhibited an excellent antioxidant activity, which could increase the expression of cytoprotective antioxidants such as HO-1 and NQ-O1, by facilitating Nrf2 nuclear transfer. These findings demonstrated that the photoprotective effects of RS were significantly improved by enzyme-modified biotransformation.

Effects of Angelica gigas Nakai as an Anti-Inflammatory Agent in In Vitro and In Vivo Atopic Dermatitis Models

PubMed Central

Ok, Seon; Oh, Sa-Rang; Jung, Tae-Sung; Jeon, Sang-Ok; Jung, Ji-wook

2018-01-01

We investigated the cellular and molecular mechanisms mediating the effects of Angelica gigas Nakai extract (AGNE) through the mitogen-activated protein kinases (MAPKs)/NF-κB pathway using in vitro and in vivo atopic dermatitis (AD) models. We examined the effects of AGNE on the expression of proinflammatory cytokines and chemokines in human mast cell line-1 (HMC-1) cells. Compound 48/80-induced pruritus and 2,4-dinitrochlorobenzene- (DNCB-) induced AD-like skin lesion mouse models were also used to investigate the antiallergic effects of AGNE. AGNE reduced histamine secretion, production of proinflammatory cytokines including interleukin- (IL-) 1β, IL-4, IL-6, IL-8, and IL-10, and expression of cyclooxygenase- (COX-) 2 in HMC-1 cells. Scratching behavior and DNCB-induced AD-like skin lesions were also attenuated by AGNE administration through the reduction of serum IgE, histamine, tumor necrosis factor-α (TNF-α), IL-6 levels, and COX-2 expression in skin tissue from mouse models. Furthermore, these inhibitory effects were mediated by the blockade of the MAPKs and NF-κB pathway. The findings of this study proved that AGNE improves the scratching behavior and atopy symptoms and reduces the activity of various atopy-related mediators in HMC-1 cells and mice model. These results suggest the AGNE has a therapeutic potential in anti-AD. PMID:29713361

Voluntary Exercise Preconditioning Activates Multiple Antiapoptotic Mechanisms and Improves Neurological Recovery after Experimental Traumatic Brain Injury

PubMed Central

Zhao, Zaorui; Sabirzhanov, Boris; Wu, Junfang; Faden, Alan I.

2015-01-01

Abstract Physical activity can attenuate neuronal loss, reduce neuroinflammation, and facilitate recovery after brain injury. However, little is known about the mechanisms of exercise-induced neuroprotection after traumatic brain injury (TBI) or its modulation of post-traumatic neuronal cell death. Voluntary exercise, using a running wheel, was conducted for 4 weeks immediately preceding (preconditioning) moderate-level controlled cortical impact (CCI), a well-established experimental TBI model in mice. Compared to nonexercised controls, exercise preconditioning (pre-exercise) improved recovery of sensorimotor performance in the beam walk task, as well as cognitive/affective functions in the Morris water maze, novel object recognition, and tail-suspension tests. Further, pre-exercise reduced lesion size, attenuated neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex. In addition, exercise preconditioning activated the brain-derived neurotrophic factor pathway before trauma and amplified the injury-dependent increase in heat shock protein 70 expression, thus attenuating key apoptotic pathways. The latter include reduction in CCI-induced up-regulation of proapoptotic B-cell lymphoma 2 (Bcl-2)-homology 3–only Bcl-2 family molecules (Bid, Puma), decreased mitochondria permeabilization with attenuated release of cytochrome c and apoptosis-inducing factor (AIF), reduced AIF translocation to the nucleus, and attenuated caspase activation. Given these neuroprotective actions, voluntary physical exercise may serve to limit the consequences of TBI. PMID:25419789

Supplementing diet with Manitoba lingonberry juice reduces kidney ischemia-reperfusion injury.

PubMed

Isaak, Cara K; Wang, Pengqi; Prashar, Suvira; O, Karmin; Brown, Daniel Cw; Debnath, Samir C; Siow, Yaw L

2017-07-01

Lingonberry (Vaccinium vitis-idaea L.) contains high levels of anthocyanins which are bioavailable in the kidney and may be protective against ischemia-reperfusion (IR)-induced acute kidney injury. This study investigated the effect of lingonberry juice on the IR-induced stress-activated signalling pathway and inflammatory response in the kidney. Sprague-Dawley rats subjected to kidney IR had significantly impaired kidney function, with increased activation of the JNK signalling pathway and increased inflammatory response, measured using a multiplex panel containing an extensive array of inflammatory biomarkers. In rats fed 1 mL lingonberry juice daily for 3 weeks prior to IR, kidney function was protected and attenuation of inflammatory response and JNK signalling was reflected in the reduction of the measured biomarkers. In vitro results in cultured HK-2 cells confirmed that lingonberry anthocyanins reduced JNK signalling and inflammatory gene expression after IR. This study shows, for the first time, that daily supplementation with lingonberry juice may protect against loss of kidney function induced by IR injury by modulating JNK signalling and inhibiting the subsequent inflammatory response. © 2017 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2017 Society of Chemical Industry. © 2017 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2017 Society of Chemical Industry.

The wheat resistance gene Lr34 results in the constitutive induction of multiple defense pathways in transgenic barley.

PubMed

Chauhan, Harsh; Boni, Rainer; Bucher, Rahel; Kuhn, Benjamin; Buchmann, Gabriele; Sucher, Justine; Selter, Liselotte L; Hensel, Goetz; Kumlehn, Jochen; Bigler, Laurent; Glauser, Gaëtan; Wicker, Thomas; Krattinger, Simon G; Keller, Beat

2015-10-01

The wheat gene Lr34 encodes an ABCG-type transporter which provides durable resistance against multiple pathogens. Lr34 is functional as a transgene in barley, but its mode of action has remained largely unknown both in wheat and barley. Here we studied gene expression in uninfected barley lines transgenic for Lr34. Genes from multiple defense pathways contributing to basal and inducible disease resistance were constitutively active in seedlings and mature leaves. In addition, the hormones jasmonic acid and salicylic acid were induced to high levels, and increased levels of lignin as well as hordatines were observed. These results demonstrate a strong, constitutive re-programming of metabolism by Lr34. The resistant Lr34 allele (Lr34res) encodes a protein that differs by two amino acid polymorphisms from the susceptible Lr34sus allele. The deletion of a single phenylalanine residue in Lr34sus was sufficient to induce the characteristic Lr34-based responses. Combination of Lr34res and Lr34sus in the same plant resulted in a reduction of Lr34res expression by 8- to 20-fold when the low-expressing Lr34res line BG8 was used as a parent. Crosses with the high-expressing Lr34res line BG9 resulted in an increase of Lr34sus expression by 13- to 16-fold in progenies that inherited both alleles. These results indicate an interaction of the two Lr34 alleles on the transcriptional level. Reduction of Lr34res expression in BG8 crosses reduced the negative pleiotropic effects of Lr34res on barley growth and vigor without compromising disease resistance, suggesting that transgenic combination of Lr34res and Lr34sus can result in agronomically useful resistance. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Nitric Oxide in the Crustacean Brain: Regulation of Neurogenesis and Morphogenesis in the Developing Olfactory Pathway

PubMed Central

Benton, J.L.; Sandeman, D.C.; Beltz, B.S.

2009-01-01

Nitric oxide (NO) plays major roles during development and in adult organisms. We examined the temporal and spatial patterns of nitric oxide synthase (NOS) appearance in the embryonic lobster brain to localize sources of NO activity; potential NO targets were identified by defining the distribution of NO-induced cGMP. Staining patterns are compared with NOS and cyclic 3,5 guanosine monophosphate (cGMP) distribution in adult lobster brains. Manipulation of NO levels influences olfactory glomerular formation and stabilization, as well as levels of neurogenesis among the olfactory projection neurons. In the first 2 days following ablation of the lateral antennular flagella in juvenile lobsters, a wave of increased NOS immunoreactivity and a reduction in neurogenesis occur. These studies implicate nitric oxide as a developmental architect and also support a role for this molecule in the neural response to injury in the olfactory pathway. PMID:17948307

Direct imaging of the disruption of hepatitis C virus replication complexes by inhibitors of lipid metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyn, Rodney K.; Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, K1N 6N5; Kennedy, David C.

2009-11-10

Here we have simultaneously characterized the influence of inhibitors of peroxisome proliferator-activated receptor alpha (PPARalpha) and the mevalonate pathway on hepatocyte lipid metabolism and the subcellular localization of hepatitis C virus (HCV) RNA using two-photon fluorescence (TPF) and coherent anti-Stokes Raman scattering (CARS) microscopy. Using this approach, we demonstrate that modulators of PPARalpha signaling rapidly cause the dispersion of HCV RNA from replication sites and simultaneously induce lipid storage and increases in lipid droplet size. We demonstrate that reductions in the levels of cholesterol resulting from inhibition of the mevalonate pathway upregulates triglyceride levels. We also show that the ratemore » of dispersion of HCV RNA is very rapid when using a PPARalpha antagonist. This occurs with a faster rate to that of direct inhibition of 3-hydroxy-3-methyglutaryl CoA reductase (HMG-CoA reductase) using lovastatin in living cells, demonstrating the potential therapeutic value of modulating host cell pathways as part of a strategy to eliminate chronic HCV infection.« less

Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells.

PubMed

Kim, Eun-Hyun; Kim, Myo-Kyoung; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Park, Kyoung-Chan; Kim, Dong-Seok

2013-10-15

Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3β and β-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation. © 2013 Elsevier B.V. All rights reserved.

Parallel evolution of Nitric Oxide signaling: Diversity of synthesis & memory pathways

PubMed Central

Moroz, Leonid L.; Kohn, Andrea B.

2014-01-01

The origin of NO signaling can be traceable back to the origin of life with the large scale of parallel evolution of NO synthases (NOSs). Inducible-like NOSs may be the most basal prototype of all NOSs and that neuronal-like NOS might have evolved several times from this prototype. Other enzymatic and non-enzymatic pathways for NO synthesis have been discovered using reduction of nitrites, an alternative source of NO. Diverse synthetic mechanisms can co-exist within the same cell providing a complex NO-oxygen microenvironment tightly coupled with cellular energetics. The dissection of multiple sources of NO formation is crucial in analysis of complex biological processes such as neuronal integration and learning mechanisms when NO can act as a volume transmitter within memory-forming circuits. In particular, the molecular analysis of learning mechanisms (most notably in insects and gastropod molluscs) opens conceptually different perspectives to understand the logic of recruiting evolutionarily conserved pathways for novel functions. Giant uniquely identified cells from Aplysia and related species precent unuque opportunities for integrative analysis of NO signaling at the single cell level. PMID:21622160

Exercise-induced biochemical changes and their potential influence on cancer: a scientific review

PubMed Central

Thomas, Robert James; Kenfield, Stacey A; Jimenez, Alfonso

2017-01-01

Aim To review and discuss the available international literature regarding the indirect and direct biochemical mechanisms that occur after exercise, which could positively, or negatively, influence oncogenic pathways. Methods The PubMed, MEDLINE, Embase and Cochrane libraries were searched for papers up to July 2016 addressing biochemical changes after exercise with a particular reference to cancer. The three authors independently assessed their appropriateness for inclusion in this review based on their scientific quality and relevance. Results 168 papers were selected and categorised into indirect and direct biochemical pathways. The indirect effects included changes in vitamin D, weight reduction, sunlight exposure and improved mood. The direct effects included insulin-like growth factor, epigenetic effects on gene expression and DNA repair, vasoactive intestinal peptide, oxidative stress and antioxidant pathways, heat shock proteins, testosterone, irisin, immunity, chronic inflammation and prostaglandins, energy metabolism and insulin resistance. Summary Exercise is one of several lifestyle factors known to lower the risk of developing cancer and is associated with lower relapse rates and better survival. This review highlights the numerous biochemical processes, which explain these potential anticancer benefits. PMID:27993842

Grb2-SH3 ligand inhibits the growth of HER2+ cancer cells and has antitumor effects in human cancer xenografts alone and in combination with docetaxel.

PubMed

Gril, Brunilde; Vidal, Michel; Assayag, Franck; Poupon, Marie-France; Liu, Wang-Qing; Garbay, Christiane

2007-07-15

HER2 represents an important signaling pathway in breast and other cancers. Herceptin has demonstrated clinical activity, but resistance is common. Thus, new therapeutic approaches to the HER2 pathway are needed. Grb2 is an adaptor protein involved in Ras-dependent signaling induced by HER2 receptors. A specific Grb2-SH3 ligand, designed and synthesized in our laboratory, called peptidimer-c, inhibited colony formation in HER2 overexpressing SKBr3 cancer cells. Combined treatment of peptidimer-c with docetaxel further inhibited both colony formation and tumor cell survival compared to docetaxel treatment alone. Efficacy of this combined treatment was correlated with a reduction in the phosphorylation of MAPK and AKT. Finally, peptidimer-c reduced the growth of a HER2(+) human breast cancer (BK111) xenograft in nude mice and potentiated the antitumor effect of docetaxel in a HER2+ hormone-independent human prostate adenocarcinoma (PAC120 HID28) xenograft. These results validate Grb2 as a new target for the HER2 pathway. (c) 2007 Wiley-Liss, Inc.

Grb2-SH3 ligand inhibits the growth of HER2+ cancer cells and has antitumor effects in human cancer xenografts alone and in combination with docetaxel

PubMed Central

Gril, Brunilde; Vidal, Michel; Assayag, Franck; Poupon, Marie-France; Liu, Wang-Qing; Garbay, Christiane

2007-01-01

HER2 represents an important signaling pathway in breast and other cancers. Herceptin has demonstrated clinical activity, but resistance is common. Thus, new therapeutic approaches to the HER2 pathway are needed. Grb2 is an adaptor protein involved in Ras-dependent signaling induced by HER2 receptors. A specific Grb2-SH3 ligand, designed and synthesized in our laboratory, called peptidimer-c, inhibited colony formation in HER2 over-expressing SKBr3 cancer cells. Combined treatment of peptidimer-c with docetaxel further inhibited both colony formation and tumor cell survival compared to docetaxel treatment alone. Efficacy of this combined treatment was correlated with a reduction in the phosphorylation of MAPK and AKT. Finally, peptidimer-c reduced the growth of a HER2+ human breast cancer (BK111) xenograft in nude mice and potentiated the anti-tumor effect of docetaxel in a HER2+ hormone-independent human prostate adenocarcinoma (PAC120 HID28) xenograft. These results validate Grb2 as a new target for the HER2 pathway. PMID:17372910

Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

PubMed Central

Liu, Fu-Chao; Tsai, Hsin-I; Yu, Huang-Ping

2015-01-01

Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed. PMID:26161238

Curcumin improves the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cells via the NF-κB-p53-caspase-3 pathway.

PubMed

Dang, Yu-Ping; Yuan, Xiao-Ying; Tian, Rong; Li, Dong-Guang; Liu, Wei

2015-04-01

Paclitaxel, isolated from Taxus brevifolia , is considered to be an efficacious agent against a wide spectrum of human cancers, including human cervical cancer. However, dose-limiting toxicity and high cost limit its clinical application. Curcumin, a nontoxic food additive, has been reported to improve paclitaxel chemotherapy in mouse models of cervical cancer. However, the underlying mechanisms remain unclear. In this study, two human cervical cancer cell lines, CaSki [human papilloma virus (HPV)16-positive] and HeLa (HPV18-positive), were selected in which to investigate the effect of curcumin on the anticancer action of paclitaxel and further clarify the mechanisms. Flow cytometry and MTT analysis demonstrated that curcumin significantly promoted paclitaxel-induced apoptosis and cytotoxicity in the two cervical cell lines compared with that observed with paclitaxel alone (P<0.05). Reverse transcription-polymerase chain reaction indicated that the decline of HPV E6 and E7 gene expression induced by paclitaxel was also assisted by curcumin. The expression levels of p53 protein and cleaved caspase-3 were increased significantly in the curcumin plus paclitaxel-treated HeLa and CaSki cells compared with those in the cells treated with paclitaxel alone (P<0.01). Significant reductions in the levels of phosphorylation of IκBα and the p65-NF-κB subunit in CaSki cells treated with curcumin and paclitaxel were observed compared with those in cells treated with paclitaxel alone (P<0.05). This suggests that the combined effect of curcumin and paclitaxel was associated with the NF-κB-p53-caspase-3 pathway. In conclusion, curcumin has the ability to improve the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cell lines via the NF-κB-p53-caspase-3 pathway. Curcumin in combination with paclitaxel may provide a superior therapeutic effect on human cervical cancer.

Reduced cAMP, Akt Activation and p65-c-Rel Dimerization: Mechanisms Involved in the Protective Effects of mGluR3 Agonists in Cultured Astrocytes

PubMed Central

Durand, Daniela; Carniglia, Lila; Caruso, Carla; Lasaga, Mercedes

2011-01-01

In recent decades, astrocytes have emerged as key pieces in the maintenance of normal functioning of the central nervous system. Any impairment in astroglial function can ultimately lead to generalized disturbance in the brain, thus pharmacological targets associated with prevention of astrocyte death are actually promising. Subtype 3 of metabotropic glutamate receptors (mGluR3) is present in astrocytes, its activation exerting neuroprotective roles. In fact, we have previously demonstrated that mGluR3 selective agonists prevent nitric oxide (NO)-induced astrocyte death. However, mechanisms responsible for that cytoprotective property are still subject to study. Although inhibition of adenylyl cyclase by mGluR3 activation was extensively reported, the involvement of reduced cAMP levels in the effects of mGluR3 agonists and the association between cAMP decrease and the downstream pathways activated by mGluR3 remain neglected. Thus, we studied intracellular signaling mediating anti-apoptotic actions of mGluR3 in cultured rat astrocytes exposed to NO. In the present work, we showed that the cytoprotective effect of mGluR3 agonists (LY379268 and LY404039) requires both the reduction of intracellular cAMP levels and activation of Akt, as assessed by MTT and TUNEL techniques. Moreover, dibutyryl-cAMP impairs Akt phosphorylation induced by LY404039, indicating a relationship between mGluR3-reduced cAMP levels and PI3K/Akt pathway activation. We also demonstrated, by co-immunoprecipitation followed by western-blot, that the mGluR3 agonists not only induce per se survival-linked interaction between members of the NF-κB family p65 and c-Rel, but also impede reduction of levels of p65-c-Rel dimers caused by NO, suggesting a possible anti-apoptotic role for p65-c-Rel. All together, these data suggest that mGluR3 agonists may regulate cAMP/Akt/p65-c-Rel pathway, which would contribute to the protective effect of mGluR3 against NO challenge in astrocytes. Our results widen the knowledge about mechanisms of action of mGluR3, potential targets for the treatment of neurodegenerative disorders where a pathophysiological role for NO has been established. PMID:21779400

Blackberry extract inhibits UVB-induced oxidative damage and inflammation through MAP kinases and NF-κB signaling pathways in SKH-1 mice skin.

PubMed

Divya, Sasidharan Padmaja; Wang, Xin; Pratheeshkumar, Poyil; Son, Young-Ok; Roy, Ram Vinod; Kim, Donghern; Dai, Jin; Hitron, John Andrew; Wang, Lei; Asha, Padmaja; Shi, Xianglin; Zhang, Zhuo

2015-04-01

Extensive exposure of solar ultraviolet-B (UVB) radiation to skin induces oxidative stress and inflammation that play a crucial role in the induction of skin cancer. Photochemoprevention with natural products represents a simple but very effective strategy for the management of cutaneous neoplasia. In this study, we investigated whether blackberry extract (BBE) reduces chronic inflammatory responses induced by UVB irradiation in SKH-1 hairless mice skin. Mice were exposed to UVB radiation (100 mJ/cm(2)) on alternate days for 10 weeks, and BBE (10% and 20%) was applied topically a day before UVB exposure. Our results show that BBE suppressed UVB-induced hyperplasia and reduced infiltration of inflammatory cells in the SKH-1 hairless mice skin. BBE treatment reduced glutathione (GSH) depletion, lipid peroxidation (LPO), and myeloperoxidase (MPO) in mouse skin by chronic UVB exposure. BBE significantly decreased the level of pro-inflammatory cytokines IL-6 and TNF-α in UVB-exposed skin. Likewise, UVB-induced inflammatory responses were diminished by BBE as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, BBE also reduced inflammatory mediators such as cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and inducible nitric oxide synthase (iNOS) levels in UVB-exposed skin. Treatment with BBE inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mouse skin. Immunohistochemistry analysis revealed that topical application of BBE inhibited the expression of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG), cyclobutane pyrimidine dimers (CPD), proliferating cell nuclear antigen (PCNA), and cyclin D1 in UVB-exposed skin. Collectively, these data indicate that BBE protects from UVB-induced oxidative damage and inflammation by modulating MAP kinase and NF-κB signaling pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

Berberine-induced AMPK activation inhibits the metastatic potential of melanoma cells via reduction of ERK activity and COX-2 protein expression.

PubMed

Kim, Hak-Su; Kim, Myung-Jin; Kim, Eun Ju; Yang, Young; Lee, Myeong-Sok; Lim, Jong-Seok

2012-02-01

Berberine is clinically important natural isoquinoline alkaloid that affects various biological functions, such as cell proliferation, migration and survival. The activation of AMP-activated protein kinase (AMPK) regulates tumor cell migration. However, the specific role of AMPK on the metastatic potential of cancer cells remains largely unknown. The present study investigated whether berberine induces AMPK activation and whether this induction directly affects mouse melanoma cell migration, adhesion and invasion. Berberine strongly increased AMPK phosphorylation via reactive oxygen species (ROS) production. 5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), a well-known AMPK activator, also inhibited tumor cell adhesion and invasion and reduced the expression of epithelial to mesenchymal transition (EMT)-related genes. Knockdown of AMPKα subunits using siRNAs significantly abated the berberine-induced inhibition of tumor cell invasion. Furthermore, berberine inhibited the metastatic potential of melanoma cells through a decrease in ERK activity and protein levels of cyclooxygenase-2 (COX-2) by a berberine-induced AMPK activation. These data were confirmed using specific MEK inhibitor, PD98059, and a COX-2 inhibitor, celecoxib. Berberine- and AICAR-treated groups demonstrated significantly decreased lung metastases in the pulmonary metastasis model in vivo. Treatment with berberine also decreased the metastatic potential of A375 human melanoma cells. Collectively, our results suggest that berberine-induced AMPK activation inhibits the metastatic potential of tumor cells through a reduction in the activity of the ERK signaling pathway and COX-2 protein levels. Copyright © 2011 Elsevier Inc. All rights reserved.

New Therapeutic Concept of NAD Redox Balance for Cisplatin Nephrotoxicity

PubMed Central

Oh, Gi-Su; Kim, Hyung-Jin; Shen, AiHua; Lee, Su-Bin; Yang, Sei-Hoon; Shim, Hyeok; Cho, Eun-Young; Kwon, Kang-Beom; Kwak, Tae Hwan; So, Hong-Seob

2016-01-01

Cisplatin is a widely used chemotherapeutic agent for the treatment of various tumors. In addition to its antitumor activity, cisplatin affects normal cells and may induce adverse effects such as ototoxicity, nephrotoxicity, and peripheral neuropathy. Various mechanisms such as DNA adduct formation, mitochondrial dysfunction, oxidative stress, and inflammatory responses are closely associated with cisplatin-induced nephrotoxicity; however, the precise mechanism remains unclear. The cofactor nicotinamide adenine dinucleotide (NAD+) has emerged as a key regulator of cellular energy metabolism and homeostasis. Recent studies have demonstrated associations between disturbance in intracellular NAD+ levels and clinical progression of various diseases through the production of reactive oxygen species and inflammation. Furthermore, we demonstrated that reduction of the intracellular NAD+/NADH ratio is critically involved in cisplatin-induced kidney damage through inflammation and oxidative stress and that increase of the cellular NAD+/NADH ratio suppresses cisplatin-induced kidney damage by modulation of potential damage mediators such as oxidative stress and inflammatory responses. In this review, we describe the role of NAD+ metabolism in cisplatin-induced nephrotoxicity and discuss a potential strategy for the prevention or treatment of cisplatin-induced adverse effects with a particular focus on NAD+-dependent cellular pathways. PMID:26881219

Phenylbutyrate inhibits homologous recombination induced by camptothecin and methyl methanesulfonate.

PubMed

Kaiser, Gitte S; Germann, Susanne M; Westergaard, Tine; Lisby, Michael

2011-08-01

Homologous recombination is accompanied by extensive changes to chromatin organization at the site of DNA damage. Some of these changes are mediated through acetylation/deacetylation of histones. Here, we show that recombinational repair of DNA damage induced by the anti-cancer drug camptothecin (CPT) and the alkylating agent methyl methanesulfonate (MMS) is blocked by sodium phenylbutyrate (PBA) in the budding yeast Saccharomyces cerevisiae. In particular, PBA suppresses CPT- and MMS-induced genetic recombination as well as DNA double-strand break repair during mating-type interconversion. Treatment with PBA is accompanied by a dramatic reduction in histone H4 lysine 8 acetylation. Live cell imaging of homologous recombination proteins indicates that repair of CPT-induced DNA damage is redirected to a non-recombinogenic pathway in the presence of PBA without loss in cell viability. In contrast, the suppression of MMS-induced recombination by PBA is accompanied by a dramatic loss in cell viability. Taken together, our results demonstrate that PBA inhibits DNA damage-induced homologous recombination likely by mediating changes in chromatin acetylation. Moreover, the combination of PBA with genotoxic agents can lead to different cell fates depending on the type of DNA damage inflicted. 2011 Elsevier B.V. All rights reserved.

A chloroplast lipoxygenase is required for wound-induced jasmonic acid accumulation in Arabidopsis.

PubMed

Bell, E; Creelman, R A; Mullet, J E

1995-09-12

Plant lipoxygenases are thought to be involved in the biosynthesis of lipid-derived signaling molecules. The potential involvement of a specific Arabidopsis thaliana lipoxygenase isozyme, LOX2, in the biosynthesis of the plant growth regulators jasmonic acid (JA) and abscisic acid was investigated. Our characterization of LOX2 indicates that the protein is targeted to chloroplasts. The physiological role of this chloroplast lipoxygenase was analyzed in transgenic plants where cosuppression reduced LOX2 accumulation. The reduction in LOX2 levels caused no obvious changes in plant growth or in the accumulation of abscisic acid. However, the wound-induced accumulation of JA observed in control plants was absent in leaves of transgenic plants that lacked LOX2. Thus, LOX2 is required for the wound-induced synthesis of the plant growth regulator JA in leaves. We also examined the expression of a wound- and JA-inducible Arabidopsis gene, vsp, in transgenic and control plants. Leaves of transgenic plants lacking LOX2 accumulated less vsp mRNA than did control leaves in response to wounding. This result suggests that wound-induced JA (or some other LOX2-requiring component of the wound response pathway) is involved in the wound-induced regulation of this gene.

Lithium protects against methamphetamine-induced neurotoxicity in PC12 cells via Akt/GSK3β/mTOR pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jintao; Zhu, Dexiao; Zhang, Jing

Methamphetamine (MA) is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to MA causes psychosis and increases the risk of Parkinson's disease. Lithium (Li) is a known mood stabilizer and has neuroprotective effects. Previous studies suggest that MA exposure decreases the phosphorylation of Akt/GSK3β pathway in vivo, whereas Li facilitates the phosphorylation of Akt/GSK3β pathway. Moreover, GSK3β and mTOR are implicated in the locomotor sensitization induced by psychostimulants and mTOR plays a critical role in MA induced toxicity. However, the effect of MA on Akt/GSK3β/mTOR pathway has not been fully investigated in vitro. Here, we found that MA exposure significantly dephosphorylated Akt/GSK3β/mTOR pathwaymore » in PC12 cells. In addition, Li remarkably attenuated the dephosphorylation effect of MA exposure on Akt/GSK3β/mTOR pathway. Furthermore, Li showed obvious protective effects against MA toxicity and LY294002 (Akt inhibitor) suppressed the protective effects of Li. Together, MA exposure dephosphorylates Akt/GSK3β/mTOR pathway in vitro, while lithium protects against MA-induced neurotoxicity via phosphorylation of Akt/GSK3β/mTOR pathway. - Highlights: • Lithium protects against methamphetamine-induced neurotoxicity in vitro. • Methamphetamine exposure dephosphorylates Akt/GSK3β/mTOR pathway. • Lithium attenuates methamphetamine-induced toxicity via phosphorylating Akt/GSK3β/mTOR pathway.« less

Systems Biology and Birth Defects Prevention: Blockade of the Glucocorticoid Receptor Prevents Arsenic-Induced Birth Defects

PubMed Central

Ahir, Bhavesh K.; Sanders, Alison P.; Rager, Julia E.

2013-01-01

Background: The biological mechanisms by which environmental metals are associated with birth defects are largely unknown. Systems biology–based approaches may help to identify key pathways that mediate metal-induced birth defects as well as potential targets for prevention. Objectives: First, we applied a novel computational approach to identify a prioritized biological pathway that associates metals with birth defects. Second, in a laboratory setting, we sought to determine whether inhibition of the identified pathway prevents developmental defects. Methods: Seven environmental metals were selected for inclusion in the computational analysis: arsenic, cadmium, chromium, lead, mercury, nickel, and selenium. We used an in silico strategy to predict genes and pathways associated with both metal exposure and developmental defects. The most significant pathway was identified and tested using an in ovo whole chick embryo culture assay. We further evaluated the role of the pathway as a mediator of metal-induced toxicity using the in vitro midbrain micromass culture assay. Results: The glucocorticoid receptor pathway was computationally predicted to be a key mediator of multiple metal-induced birth defects. In the chick embryo model, structural malformations induced by inorganic arsenic (iAs) were prevented when signaling of the glucocorticoid receptor pathway was inhibited. Further, glucocorticoid receptor inhibition demonstrated partial to complete protection from both iAs- and cadmium-induced neurodevelopmental toxicity in vitro. Conclusions: Our findings highlight a novel approach to computationally identify a targeted biological pathway for examining birth defects prevention. PMID:23458687

Central mechanisms of stress-induced headache.

PubMed

Cathcart, S; Petkov, J; Winefield, A H; Lushington, K; Rolan, P

2010-03-01

Stress is the most commonly reported trigger of an episode of chronic tension-type headache (CTTH); however, the causal significance has not been experimentally demonstrated to date. Stress may trigger CTTH through hyperalgesic effects on already sensitized pain pathways in CTTH sufferers. This hypothesis could be partially tested by examining pain sensitivity in an experimental model of stress-induced headache in CTTH sufferers. Such examinations have not been reported to date. We measured pericranial muscle tenderness and pain thresholds at the finger, head and shoulder in 23 CTTH sufferers (CTH-S) and 25 healthy control subjects (CNT) exposed to an hour-long stressful mental task, and in 23 CTTH sufferers exposed to an hour-long neutral condition (CTH-N). Headache developed in 91% of CTH-S, 4% of CNT, and 17% of CTH-N subjects. Headache sufferers had increased muscle tenderness and reduced pain thresholds compared with healthy controls. During the task, muscle tenderness increased and pain thresholds decreased in the CTH-S group compared with CTH-N and CNT groups. Pre-task muscle tenderness and reduction in pain threshold during task were predictive of the development and intensity of headache following task. The main findings are that stress induced a headache in CTTH sufferers, and this was associated with pre-task muscle tenderness and stress-induced reduction in pain thresholds. The results support the hypothesis that stress triggers CTTH through hyperalgesic effects on already increased pain sensitivity in CTTH sufferers, reducing the threshold to noxious input from pericranial structures.

Amadori products promote cellular senescence activating insulin-like growth factor-1 receptor and down-regulating the antioxidant enzyme catalase.

PubMed

Del Nogal-Ávila, María; Troyano-Suárez, Nuria; Román-García, Pablo; Cannata-Andía, Jorge B; Rodriguez-Puyol, Manuel; Rodriguez-Puyol, Diego; Kuro-O, Makoto; Ruiz-Torres, María P

2013-07-01

Activation of the insulin growth factor receptor-1 signaling pathways has been largely related to the aging process. Amadori products are produced in pathological conditions such as diabetes and aging, and are potentially involved in diabetic nephropathy or age-associated decline of renal function. We hypothesize that Amadori products induce senescence in primary human mesangial cells through the activation of IGF-1 receptor and investigate, in the present work, the intracellular mechanism involved after this activation. We treated cultured human mesangial cells with glycated albumin, one of the most abundant Amadori product, and senescence was assessed by determining the senescence associated β-galactosidase activity and the expression of the cell cycle regulators p53 and p21. We demonstrated that prolonged exposition (more than 24h) to glycated albumin induced senescence and, in parallel, incremented the release of IGF-1 and the activation of the IGF-1 receptor. Inhibition of the IGF-1 activation prevented the GA induced senescence. Activation of IGF-1R, after GA addition, promoted a reduction in the catalase content through the constitutive activation of Ras and erk1/2 proteins which were, in turn, responsible of the observed GA-induced senescence. In conclusion, we propose that the Amadori product, glycated albumin, promotes premature cell senescence in mesangial cells through the activation of the IGF-1 receptor and the subsequent reduction in the antioxidant enzyme catalase. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recombinant heat shock protein 27 (HSP27/HSPB1) protects against cadmium-induced oxidative stress and toxicity in human cervical cancer cells.

PubMed

Alvarez-Olmedo, Daiana G; Biaggio, Veronica S; Koumbadinga, Geremy A; Gómez, Nidia N; Shi, Chunhua; Ciocca, Daniel R; Batulan, Zarah; Fanelli, Mariel A; O'Brien, Edward R

2017-05-01

Cadmium (Cd) is a carcinogen with several well-described toxicological effects in humans, but its molecular mechanisms are still not fully understood. Overexpression of heat shock protein 27 (HSP27/HSPB1)-a multifunctional protein chaperone-has been shown to protect cells from oxidative damage and apoptosis triggered by Cd exposure. The aims of this work were to investigate the potential use of extracellular recombinant HSP27 to prevent/counteract Cd-induced cellular toxicity and to evaluate if peroxynitrite was involved in the development of Cd-induced toxicity. Here, we report that the harmful effects of Cd correlated with changes in oxidative stress markers: upregulation of reactive oxygen species, reduction in nitric oxide (NO) bioavailability, increment in lipid peroxidation, peroxynitrite (PN), and protein nitration; intracellular HSP27 was reduced. Treatments with Cd (100 μM) for 24 h or with the peroxynitrite donor, SIN-1, decreased HSP27 levels (~50%), suggesting that PN formation is responsible for the reduction of HSP27. Pre-treatments of the cells either with Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) (a pharmacological inhibitor of NO synthase) or with recombinant HSP27 (rHSP27) attenuated the disruption of the cellular metabolism induced by Cd, increasing in a 55 and 52%, respectively, the cell viability measured by CCK-8. Cd induced necrotic cell death pathways, although apoptosis was also activated; pre-treatment with L-NAME or rHSP27 mitigated cell death. Our findings show for the first time a direct relationship between Cd-induced toxicity and PN production and a role for rHSP27 as a potential therapeutic agent that may counteract Cd toxicity.

4-O-Methylhonokiol Protects HaCaT Cells from TGF-β1-Induced Cell Cycle Arrest by Regulating Canonical and Non-Canonical Pathways of TGF-β Signaling

PubMed Central

Kim, Sang-Cheol; Kang, Jung-Il; Hyun, Jin-Won; Kang, Ji-Hoon; Koh, Young-Sang; Kim, Young-Heui; Kim, Ki-Ho; Ko, Ji-Hee; Yoo, Eun-Sook; Kang, Hee-Kyoung

2017-01-01

4-O-methylhonokiol, a neolignan compound from Magnolia Officinalis, has been reported to have various biological activities including hair growth promoting effect. However, although transforming growth factor-β (TGF-β) signal pathway has an essential role in the regression induction of hair growth, the effect of 4-O-methylhonokiol on the TGF-β signal pathway has not yet been elucidated. We thus examined the effect of 4-O-methylhonokiol on TGF-β-induced canonical and noncanonical pathways in HaCaT human keratinocytes. When HaCaT cells were pretreated with 4-O-methylhonokiol, TGF-β1-induced G1/G0 phase arrest and TGF-β1-induced p21 expression were decreased. Moreover, 4-O-methylhonokiol inhibited nuclear translocation of Smad2/3, Smad4 and Sp1 in TGF-β1-induced canonical pathway. We observed that ERK phosphorylation by TGF-β1 was significantly attenuated by treatment with 4-O-methylhonokiol. 4-O-methylhonokiol inhibited TGF-β1-induced reactive oxygen species (ROS) production and reduced the increase of NADPH oxidase 4 (NOX4) mRNA level in TGF-β1-induced noncanonical pathway. These results indicate that 4-O-methylhonokiol could inhibit TGF-β1-induced cell cycle arrest through inhibition of canonical and noncanonical pathways in human keratinocyte HaCaT cell and that 4-O-methylhonokiol might have protective action on TGF-β1-induced cell cycle arrest. PMID:28190316

6-mercaptopurine (6-MP) induces p53-mediated apoptosis of neural progenitor cells in the developing fetal rodent brain.

PubMed

Kanemitsu, H; Yamauchi, H; Komatsu, M; Yamamoto, S; Okazaki, S; Uchida, K; Nakayama, H

2009-01-01

6-mercaptopurine (6-MP), a DNA-damaging agent, induces apoptosis of neural progenitor cells, and causes malformation in the fetal brain. The aim of the present study is to clarify the molecular pathway of 6-MP-induced apoptosis of neural progenitor cells in the fetal telencephalon of rats and mice. p53 protein is activated by DNA damage and induces apoptosis through either the intrinsic pathway involving the mitochondria or the extrinsic pathway triggered by death receptors. In this study, the expression of puma and cleaved caspase-9 proteins, which are specific intrinsic pathway factors, increased in the rat telencephalon after 6-MP treatment. 6-MP-induced apoptosis of neural progenitor cells was completely absent in p53-deficient mice. On the other hand, the expression of Fas protein, an extrinsic pathway factor, did not change throughout the experimental period in the rat telencephalon treated with 6-MP. The number of apoptotic neural progenitor cells was similar among Fas-mutated lpr/lpr and wild-type mice, suggesting that the Fas pathway does not play a significant role in 6-MP-induced apoptosis of neural progenitor cells. These results may suggest that the p53-mediated intrinsic pathway is essential for 6-MP-induced apoptosis of neural progenitor cells in the developing telencephalon of rats and mice.

Astragaloside IV controls collagen reduction in photoaging skin by improving transforming growth factor-β/Smad signaling suppression and inhibiting matrix metalloproteinase-1.

PubMed

Chen, Bin; Li, Ran; Yan, Ning; Chen, Gang; Qian, Wen; Jiang, Hui-Li; Ji, Chao; Bi, Zhi-Gang

2015-05-01

Exposure to ultraviolet (UV) light reduces levels of type I collagen in the dermis and results in human skin damage and premature skin aging (photoaging). This leads to a wrinkled appearance through the inhibition of transforming growth factor‑β (TGF‑β)/Smad signaling. UV irradiation increases type I collagen degradation through upregulating matrix metalloproteinase (MMP) expression. Astragaloside IV (AST) is one of the major active components extracted from Astragalus membranaceus. However, its multiple anti‑photoaging effects remain to be elucidated. In the present study, the effects of AST against collagen reduction in UV‑induced skin aging in human skin fibroblasts were investigated. The expression of type I procollagen (COL1), MMP‑1, TGF‑βRⅡ and Smad7 were determined using reverse transcription‑polymerase chain reaction, western blotting and ELISA, respectively. UV irradiation inhibits type I collagen production by suppressing the TGF‑β/Smad signaling pathway and increasing COL1 degradation by inducing MMP‑1 expression. Transforming growth factor‑β type II protein and COL1 mRNA decreased but MMP‑1 and Smad7 levels increased in the photoaging model group, which was reversed by topical application of AST. AST prevents collagen reduction from UV irradiation in photoaging skin by improving TGF‑β/Smad signaling suppression and inhibiting MMP‑1, thus AST may be a potential agent against skin photoaging.

REDUCTION OF ALDOSTERONE PRODUCTION IMPROVES RENAL OXIDATIVE STRESS AND FIBROSIS IN DIABETIC RATS

PubMed Central

Matavelli, Luis C.; Siragy, Helmy M.

2012-01-01

SUMMARY Aldosterone is increased in diabetes and contributes to the development of diabetic nephropathy. We hypothesized that reduction in aldosterone production in diabetes by amlodipine or aliskiren improves diabetic kidney disease by attenuating renal oxidative stress and fibrosis. Normoglycemic and streptozotocin-induced diabetes Sprague-Dawley rats were given vehicle, amlodipine or aliskiren individually and combined for six weeks. At the end of study, we evaluated BP, 24h urinary sodium (UNaV) and aldosterone excretion rates, renal interstitial fluid (RIF) levels of nitric oxide (NO), cGMP and 8-isoprostane, and renal morphology. BP was not significantly different between any of experimental groups. UNaV increased in diabetic animals and was not affected by different treatments. Urinary aldosterone excretion increased in diabetic rats receiving vehicle and decreased with amlodipine and aliskiren individually or combined. RIF NO and cGMP levels were reduced in vehicle treated diabetic rats and increased with amlodipine or aliskiren given individually and combined. RIF 8-isoprostane levels and renal immunostaining for PAS and fibronectin were increased in vehicle treated diabetic rats and decreased with aliskiren individually or combined with amlodipine. We conclude that inhibition of aldosterone by amlodipine or aliskiren ameliorates diabetes induced renal injury via improvement of NO-cGMP pathway, and reduction in oxidative stress and fibrosis, independent of BP changes. PMID:23011470

The nitric-oxide reductase from Paracoccus denitrificans uses a single specific proton pathway.

PubMed

ter Beek, Josy; Krause, Nils; Reimann, Joachim; Lachmann, Peter; Ädelroth, Pia

2013-10-18

The NO reductase from Paracoccus denitrificans reduces NO to N2O (2NO + 2H(+) + 2e(-) → N2O + H2O) with electrons donated by periplasmic cytochrome c (cytochrome c-dependent NO reductase; cNOR). cNORs are members of the heme-copper oxidase superfamily of integral membrane proteins, comprising the O2-reducing, proton-pumping respiratory enzymes. In contrast, although NO reduction is as exergonic as O2 reduction, there are no protons pumped in cNOR, and in addition, protons needed for NO reduction are derived from the periplasmic solution (no contribution to the electrochemical gradient is made). cNOR thus only needs to transport protons from the periplasm into the active site without the requirement to control the timing of opening and closing (gating) of proton pathways as is needed in a proton pump. Based on the crystal structure of a closely related cNOR and molecular dynamics simulations, several proton transfer pathways were suggested, and in principle, these could all be functional. In this work, we show that residues in one of the suggested pathways (denoted pathway 1) are sensitive to site-directed mutation, whereas residues in the other proposed pathways (pathways 2 and 3) could be exchanged without severe effects on turnover activity with either NO or O2. We further show that electron transfer during single-turnover reduction of O2 is limited by proton transfer and can thus be used to study alterations in proton transfer rates. The exchange of residues along pathway 1 showed specific slowing of this proton-coupled electron transfer as well as changes in its pH dependence. Our results indicate that only pathway 1 is used to transfer protons in cNOR.

Selective collision-induced fragmentation of ortho-hydroxybenzyl-aminated lysyl-containing tryptic peptides.

PubMed

Simon, E S; Papoulias, P G; Andrews, P C

2013-07-30

In protein studies that employ tandem mass spectrometry the manipulation of protonated peptide fragmentation through exclusive dissociation pathways may be preferred in some applications over the comprehensive amide backbone fragmentation that is typically observed. In this study, we characterized the selective cleavage of the side-chain Cζ-Nε bond of peptides with ortho-hydroxybenzyl-aminated lysine residues. Internal lysyl residues of representative peptides were derivatized via reductive amination with ortho-hydroxybenzaldehyde. The modified peptides were analyzed using collision-induced dissociation (CID) on an Orbitrap tandem mass spectrometer. Theoretical calculations using computational methods (density functional theory) were performed to investigate the potential dissociation mechanisms for the Cζ-Nε bond of the derivatized lysyl residue resulting in the formation of the observed product ions. Tandem mass spectra of the derivatized peptide ions exhibit product peaks corresponding to selective cleavage of the side-chain Cζ-Nε bond that links the derivative to lysine. The ortho-hydroxybenzyl derivative is released either as a neutral moiety [C7H6O1] or as a carbocation [C7H7O1](+) through competing pathways (retro-Michael versus Carbocation Elimination (CCE), respectively). The calculated transition state activation barriers indicate that the retro-Michael pathway is kinetically favored over CCE and both are favored over amide cleavage. The application of ortho-hydroxybenzyl amination is a promising peptide derivatization scheme for promoting selective dissociation pathways in the tandem mass spectrometry of protonated peptides. This can be implemented in the rational development of peptide reactive reagents for applications that may benefit from selective fragmentation paths (including crosslinking or MRM reagents). Copyright © 2013 John Wiley & Sons, Ltd.

Resveratrol improves neurological outcome and neuroinflammation following spinal cord injury through enhancing autophagy involving the AMPK/mTOR pathway.

PubMed

Meng, Hong-Yu; Shao, De-Cheng; Li, Han; Huang, Xiao-Dan; Yang, Guang; Xu, Bing; Niu, Hai-Yun

2018-06-19

Resveratrol, a natural phenolic compound, provides neuroprotective effects, however, the specific mechanisms of action remain to be elucidated. The purpose of the present study was to examine the neuroprotective effect of resveratrol on spinal cord injury (SCI) and the potential molecular mechanisms of action. A rat model of SCI was induced using Allen's method, and resveratrol (100 mg/kg) was intraperitoneally injected 1 day following surgery. The recovery of neurological function was assessed using the Basso, Beattie, Bresnahan scoring system and an inclined plane test. The concentrations of pro‑ and anti‑inflammatory factors were measured using ELISA. The expression and location of autophagy markers were measured using western blot and immunofluorescence analyses. The results suggested that resveratrol administration resulted in functional improvement of locomotor activity and reduced neuroinflammation following the induction of SCI. In addition, autophagy was activated following SCI, as demonstrated by the significantly increased ratio of microtubule‑associated protein light chain 3 (LC3)‑II/LC3‑I and expression of Beclin‑1 in the injured spinal cord. Of note, the enhancement of phosphorylated (p)‑AMP‑activated protein kinase (AMPK) and the reduction of p‑mammalian target of rapamycin (mTOR) following SCI indicated that the SCI‑induced activation of autophagy was associated with the AMPK/mTOR signaling pathway. Resveratrol treatment further enhanced the activation of autophagy via the AMPK/mTOR pathway following SCI. By contrast, the autophagic inhibitor, 3‑methyladenine, partially inhibited the neuroprotective effects of resveratrol treatment. Together, these findings suggested that resveratrol promoted functional recovery and inhibited neuroinflammation through the activation of autophagy mediated by the AMPK/mTOR pathway following SCI.

Exosomes play an important role in the process of psoralen reverse multidrug resistance of breast cancer.

PubMed

Wang, Xiaohong; Xu, Chengfeng; Hua, Yitong; Sun, Leitao; Cheng, Kai; Jia, Zhongming; Han, Yong; Dong, Jianli; Cui, Yuzhen; Yang, Zhenlin

2016-12-01

Release of exosomes have been shown to play critical roles in drug resistance by delivering cargo. Targeting the transfer of exosomes from resistant cells to sensitive cells may be an approach to overcome some cases of drug resistance. In this study, we investigated the potential role of exosomes in the process of psoralen reverse multidrug resistance of MCF-7/ADR cells. Exosomes were isolated by differential centrifugation of culture media from MCF-7/ADR cells (ADR/exo) and MCF-7 parental cells (S/exo). Exosomes were characterized by morphology, exosomal markers and size distribution. The ability of ADR/exo to transfer multidrug resistance was assessed by MTT and real-time quantitative PCR. The different formation and secretion of exosomes were detected by immunofluorescence and transmission electron microscopy. Then we performed comparative transcriptomic analysis using RNA-Seq technology and real-time quantitative PCR to better understand the gene expression regulation in exosmes formation and release after psoralen treatment. Our data showed that exosomes derived from MCF-7/ADR cells were able to promote active sequestration of drugs and could induce a drug resistance phenotype by transferring drug-resistance-related gene MDR-1 and P-glycoprotein protein. Psoralen could reduce the formation and secretion of exosomes to overcome drug resistance. There were 21 differentially expressed genes. Gene ontology (GO) pathway analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the most significantly expressed genes were linked to PPAR and P53 signaling pathways which were related to exosomes formation, secretion and cargo sorting. Psoralen can affect the exosomes and induce the reduction of resistance transmission via exosomes might through PPAR and P53 signaling pathways, which might provide a novel strategy for breast cancer resistance to chemotherapy in the future.

Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Sunga; Lim, Mi-Hee; Kim, Ki Mo

2011-12-15

Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specificmore » features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: Black-Right-Pointing-Pointer We studied the mechanism which cordycepin-induced cell death association with estrogen receptor (ER) in breast cancer cells, MDA-MB-231 and MCF-7. Black-Right-Pointing-Pointer The cordycepin-induced cell death in MDA-MB-231 cells was associated with the mitochondria-mediated apoptotic pathway. Black-Right-Pointing-Pointer Cordycepin treatment also resulted in autophagy in MCF-7 cells, associated with induction of autophagosome formation. Black-Right-Pointing-Pointer The different cordycepin-mediated cell death pathways are irrespective of the ER response. Black-Right-Pointing-Pointer Cordycepin proves a clinically useful, ER-independent chemotherapeutic agent for human breast cancer cells.« less

The hepatocyte-specific HNF4α/miR-122 pathway contributes to iron overload-mediated hepatic inflammation.

PubMed

Li, Min; Tang, Yuxiao; Wu, Lusha; Mo, Fengfeng; Wang, Xin; Li, Hongxia; Qi, Ruirui; Zhang, Hongwei; Srivastava, Arun; Ling, Chen

2017-08-24

Hepatic iron overload (IO) is a major complication of transfusional therapy. It was generally thought that IO triggers substantial inflammatory responses by producing reactive oxygen species in hepatic macrophages. Recently, a decrease in microRNA-122 (miR-122) expression was observed in a genetic knockout (Hfe -/- ) mouse model of IO. Because hepatocyte-enriched miR-122 is a key regulator of multiple hepatic pathways, including inflammation, it is of interest whether hepatocyte directly contributes to IO-mediated hepatic inflammation. Here, we report that IO induced similar inflammatory responses in human primary hepatocytes and Thp-1-derived macrophages. In the mouse liver, IO resulted in altered expression of not only inflammatory genes but also >230 genes that are known targets of miR-122. In addition, both iron-dextran injection and a 3% carbonyl iron-containing diet led to upregulation of hepatic inflammation, which was associated with a significant reduction in HNF4α expression and its downstream target, miR-122. Interestingly, the same signaling pathway was changed in macrophage-deficient mice, suggesting that macrophages are not the only target of IO. Most importantly, hepatocyte-specific overexpression of miR-122 rescued IO-mediated hepatic inflammation. Our findings indicate the direct involvement of hepatocytes in IO-induced hepatic inflammation and are informative for developing new molecular targets and preventative therapies for patients with major hemoglobinopathy. © 2017 by The American Society of Hematology.

Electrochemical Impedance Spectroscopy for Real-Time Detection of Lipid Membrane Damage Based on a Porous Self-Assembly Monolayer Support.

PubMed

Zhang, Meng; Zhai, Qingyu; Wan, Liping; Chen, Li; Peng, Yu; Deng, Chunyan; Xiang, Juan; Yan, Jiawei

2018-06-19

Layer-by-layer dissolution and permeable pore formation are two typical membrane damage pathways, which induce membrane function disorder and result in serious disease, such as Alzheimer's disease, Keshan disease, Sickle-cell disease, and so on. To effectively distinguish and sensitively monitor these two typical membrane damage pathways, a facile electrochemical impedance strategy was developed on a porous self-assembly monolayer (pSAM) supported bilayer lipid membrane (BLM). The pSAM was prepared by selectively electrochemical reductive desorption of the mercaptopropionic acid in a mixed mercaptopropionic acid/11-mercaptoundecanoic acid self-assembled monolayer, which created plenty of nanopores with tens of nanometers in diameter and several nanometers in height (defined as inner-pores). The ultralow aspect ratio of the inner-pores was advantageous to the mass transfer of electrochemical probe [Fe(CN) 6 ] 3-/4- , simplifying the equivalent electric circuit for electrochemical impedance spectroscopy analysis at the electrode/membrane interface. [Fe(CN) 6 ] 3-/4- transferring from the bulk solution into the inner-pore induce significant changes of the interfacial impedance properties, improving the detection sensitivity. Based on these, the different membrane damage pathways were effectively distinguished and sensitively monitored with the normalized resistance-capacitance changes of inner-pore-related parameters including the electrolyte resistance within the pore length ( R pore ) and the metal/inner-pore interfacial capacitance ( C pore ) and the charge-transfer resistance ( R ct-in ) at the metal/inner-pore interface.

AMPK induced memory improvements in the diabetic population: A case study.

PubMed

Halikas, Alicia; Gibas, Kelly J

2018-04-27

Diabetics in mid-life carry a 1.5 times higher risk of developing Alzheimer's disease than those diagnosed with diabetes (T2D) later in life [1]. Recent research points to accelerated cognitive decline within a range of 20%-50% for middle-aged diabetics as compared to non-diabetic populations [2,3]. Metabolic syndrome (MetS), a type 2 diabetes (T2D) precursor, is also linked to MCI and AD pathologies via hypo-metabolic brain circuitry that inhibits glucose metabolism and attenuates cognitive function [4]. Dysregulation of intracellular and extracellular signaling as mediated by the mTOR and AMPK pathways is the result. These critical nutrient sensing pathways modulate epigenetic shifts in the genome by channeling fuel substrates either towards mitochondrial fatty acid oxidation (AMPK) or cytosolic glycolysis and substrate level phosphorylation (mTOR) [5]. This case study was designed to examine the link between peripheral insulin resistance and early stage memory loss in a type 2 diabetic male. Reactivating the AMPK pathway via induced and controlled nutritional ketosis combined with high intensity interval training (HIIT) (in order to inhibit mTOR signaling) were primary features of the 10 week intervention. Post intervention results revealed statistically significant reductions in HgA1c, fasting insulin and HOMA-IR (homeostatic model assessment of insulin resistance). Restoring peripheral and hypothalamic insulin sensitivity by way of AMPK activation may restore memory function, improve neuroplasticity, and normalize MetS biomarkers (Demetrius and Driver, 2014; [4,6]). Copyright © 2018. Published by Elsevier Ltd.

Ouabain rescues rat nephrogenesis during intrauterine growth restriction by regulating the complement and coagulation cascades and calcium signaling pathway.

PubMed

Chen, L; Yue, J; Han, X; Li, J; Hu, Y

2016-02-01

Intrauterine growth restriction (IUGR) is associated with a reduction in the numbers of nephrons in neonates, which increases the risk of hypertension. Our previous study showed that ouabain protects the development of the embryonic kidney during IUGR. To explore this molecular mechanism, IUGR rats were induced by protein and calorie restriction throughout pregnancy, and ouabain was delivered using a mini osmotic pump. RNA sequencing technology was used to identify the differentially expressed genes (DEGs) of the embryonic kidneys. DEGs were submitted to the Database for Annotation and Visualization and Integrated Discovery, and gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted. Maternal malnutrition significantly reduced fetal weight, but ouabain treatment had no significant effect on body weight. A total of 322 (177 upregulated and 145 downregulated) DEGs were detected between control and the IUGR group. Meanwhile, 318 DEGs were found to be differentially expressed (180 increased and 138 decreased) between the IUGR group and the ouabain-treated group. KEGG pathway analysis indicated that maternal undernutrition mainly disrupts the complement and coagulation cascades and the calcium signaling pathway, which could be protected by ouabain treatment. Taken together, these two biological pathways may play an important role in nephrogenesis, indicating potential novel therapeutic targets against the unfavorable effects of IUGR.

Cardiotonic steroids-mediated Na+/K+-ATPase targeting could circumvent various chemoresistance pathways.

PubMed

Mijatovic, Tatjana; Kiss, Robert

2013-03-01

Many cancer patients fail to respond to chemotherapy because of the intrinsic resistance of their cancer to pro-apoptotic stimuli or the acquisition of the multidrug resistant phenotype during chronic treatment. Previous data from our groups and from others point to the sodium/potassium pump (the Na+/K+-ATPase, i.e., NaK) with its highly specific ligands (i.e., cardiotonic steroids) as a new target for combating cancers associated with dismal prognoses, including gliomas, melanomas, non-small cell lung cancers, renal cell carcinomas, and colon cancers. Cardiotonic steroid-mediated Na+/K+-ATPase targeting could circumvent various resistance pathways. The most probable pathways include the involvement of Na+/K+-ATPase β subunits in invasion features and Na+/K+-ATPase α subunits in chemosensitisation by specific cardiotonic steroid-mediated apoptosis and anoïkis-sensitisation; the regulation of the expression of multidrug resistant-related genes; post-translational regulation, including glycosylation and ubiquitinylation of multidrug resistant-related proteins; c-Myc downregulation; hypoxia-inducible factor downregulation; NF-κB downregulation and deactivation; the inhibition of the glycolytic pathway with a reduction of intra-cellular ATP levels and an induction of non-apoptotic cell death. The aims of this review are to examine the various molecular pathways by which the NaK targeting can be more deleterious to biologically aggressive cancer cells than to normal cells. Georg Thieme Verlag KG Stuttgart · New York.

Dual targeting of HER3 and MEK may overcome HER3-dependent drug-resistance of colon cancers

PubMed Central

Bon, Giulia; Loria, Rossella; Amoreo, Carla Azzurra; Verdina, Alessandra; Sperduti, Isabella; Mastrofrancesco, Arianna; Soddu, Silvia; Diodoro, Maria Grazia; Mottolese, Marcella; Todaro, Matilde; Stassi, Giorgio; Milella, Michele; De Maria, Ruggero; Falcioni, Rita

2017-01-01

Although the medical treatment of colorectal cancer has evolved greatly in the last years, a significant portion of early-stage patients develops recurrence after therapies. The current clinical trials are directed to evaluate new drug combinations and treatment schedules. By the use of patient-derived or established colon cancer cell lines, we found that the tyrosine kinase receptor HER3 is involved in the mechanisms of resistance to therapies. In agreement, the immunohistochemical analysis of total and phospho-HER3 expression in 185 colorectal cancer specimens revealed a significant correlation with lower disease-free survival. Targeting HER3 by the use of the monoclonal antibody patritumab we found induction of growth arrest in all cell lines. Despite the high efficiency of patritumab in abrogating the HER3-dependent activation of PI3K pathway, the HER2 and EGFR-dependent MAPK pathway is activated as a compensatory mechanism. Interestingly, we found that the MEK-inhibitor trametinib inhibits, as expected, the MAPK pathway but induces the HER3-dependent activation of PI3K pathway. The combined treatment results in the abrogation of both PI3K and MAPK pathways and in a significant reduction of cell proliferation and survival. These data suggest a new strategy of therapy for HER3-overexpressing colon cancers. PMID:29312543

Chemical genetic screen identifies lithocholic acid as an anti-aging compound that extends yeast chronological life span in a TOR-independent manner, by modulating housekeeping longevity assurance processes.

PubMed

Goldberg, Alexander A; Richard, Vincent R; Kyryakov, Pavlo; Bourque, Simon D; Beach, Adam; Burstein, Michelle T; Glebov, Anastasia; Koupaki, Olivia; Boukh-Viner, Tatiana; Gregg, Christopher; Juneau, Mylène; English, Ann M; Thomas, David Y; Titorenko, Vladimir I

2010-07-01

In chronologically aging yeast, longevity can be extended by administering a caloric restriction (CR) diet or some small molecules. These life-extending interventions target the adaptable target of rapamycin (TOR) and cAMP/protein kinase A (cAMP/PKA) signaling pathways that are under the stringent control of calorie availability. We designed a chemical genetic screen for small molecules that increase the chronological life span of yeast under CR by targeting lipid metabolism and modulating housekeeping longevity pathways that regulate longevity irrespective of the number of available calories. Our screen identifies lithocholic acid (LCA) as one of such molecules. We reveal two mechanisms underlying the life-extending effect of LCA in chronologically aging yeast. One mechanism operates in a calorie availability-independent fashion and involves the LCA-governed modulation of housekeeping longevity assurance pathways that do not overlap with the adaptable TOR and cAMP/PKA pathways. The other mechanism extends yeast longevity under non-CR conditions and consists in LCA-driven unmasking of the previously unknown anti-aging potential of PKA. We provide evidence that LCA modulates housekeeping longevity assurance pathways by suppressing lipid-induced necrosis, attenuating mitochondrial fragmentation, altering oxidation-reduction processes in mitochondria, enhancing resistance to oxidative and thermal stresses, suppressing mitochondria-controlled apoptosis, and enhancing stability of nuclear and mitochondrial DNA.

Pheromone-Induced Morphogenesis Improves Osmoadaptation Capacity by Activating the HOG MAPK Pathway**

PubMed Central

Baltanás, Rodrigo; Bush, Alan; Couto, Alicia; Durrieu, Lucía; Hohmann, Stefan; Colman-Lerner, Alejandro

2013-01-01

Environmental and internal conditions expose cells to a multiplicity of stimuli whose consequences are difficult to predict. Here, we investigate the response to mating pheromone of yeast cells adapted to high osmolarity. Events downstream of pheromone binding involve two mitogen-activated protein kinase (MAPK) cascades: the pheromone response (PR) and the cell-wall integrity response (CWI). Although these MAPK pathways share components with each and a third MAPK pathway, the high osmolarity response (HOG), they are normally only activated by distinct stimuli, a phenomenon called insulation. We found that in cells adapted to high osmolarity, PR activated the HOG pathway in a pheromone- and osmolarity- dependent manner. Activation of HOG by the PR was not due to loss of insulation, but rather a response to a reduction in internal osmolarity, which resulted from an increase in glycerol release caused by the PR. By analyzing single-cell time courses, we found that stimulation of HOG occurred in discrete bursts that coincided with the “shmooing” morphogenetic process. Activation required the polarisome, the cell wall integrity MAPK Slt2, and the aquaglyceroporin Fps1. HOG activation resulted in high glycerol turnover that improved adaptability to rapid changes in osmolarity. Our work shows how a differentiation signal can recruit a second, unrelated sensory pathway to enable responses to yeast to multiple stimuli. PMID:23612707

ERβ induces the differentiation of cultured osteoblasts by both Wnt/β-catenin signaling pathway and estrogen signaling pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Xinhua; Wang, Xiaoyuan; Hu, Xiongke

Although 17β-estradial (E2) is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/β-catenin pathway as a major signaling cascade in bone biology. The interactions between Wnt/β-catenin signaling pathway and estrogen signaling pathways have been reported in many tissues. In this study, E2 significantly increased the expression of β-catenin by inducing phosphorylations of GSK3β at serine 9. ERβ siRNAs were transfected into MC3T3-E1 cells and revealed that ERβ involved E2-induced osteoblasts proliferation and differentiation via Wnt/β-catenin signaling. The osteoblast differentiation genes (BGP, ALP and OPN) and proliferation related gene (cyclin D1) expressionmore » were significantly induced by E2-mediated ERβ. Furthermore immunofluorescence and immunoprecipitation analysis demonstrated that E2 induced the accumulation of β-catenin protein in the nucleus which leads to interaction with T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors. Taken together, these findings suggest that E2 promotes osteoblastic proliferation and differentiation by inducing proliferation-related and differentiation-related gene expression via ERβ/GSK-3β-dependent Wnt/β-catenin signaling pathway. Our findings provide novel insights into the mechanisms of action of E2 in osteoblastogenesis. - Highlights: • 17β-estradial (E2) promotes GSK3-β phosphorylation. • E2 activates the Wnt/β-catenin signaling pathway. • The Wnt/β-catenin signaling pathway interacts with estrogen signaling pathways. • E2-mediated ER induced osteoblast differentiation and proliferation related genes expression.« less

Metadherin facilitates podocyte apoptosis in diabetic nephropathy

PubMed Central

Liu, Wen-Ting; Peng, Fen-Fen; Li, Hong-Yu; Chen, Xiao-Wen; Gong, Wang-Qiu; Chen, Wen-Jing; Chen, Yi-Hua; Li, Pei-Lin; Li, Shu-Ting; Xu, Zhao-Zhong; Long, Hai-Bo

2016-01-01

Apoptosis, one of the major causes of podocyte loss, has been reported to have a vital role in diabetic nephropathy (DN) pathogenesis, and understanding the mechanisms underlying the regulation of podocyte apoptosis is crucial. Metadherin (MTDH) is an important oncogene, which is overexpressed in most cancers and responsible for apoptosis, metastasis, and poor patient survival. Here we show that the expression levels of Mtdh and phosphorylated p38 mitogen-activated protein kinase (MAPK) are significantly increased, whereas those of the microRNA-30 family members (miR-30s) are considerably reduced in the glomeruli of DN rat model and in high glucose (HG)-induced conditionally immortalized mouse podocytes (MPC5). These levels are positively correlated with podocyte apoptosis rate. The inhibition of Mtdh expression, using small interfering RNA, but not Mtdh overexpression, was shown to inhibit HG-induced MPC5 apoptosis and p38 MAPK pathway, and Bax and cleaved caspase 3 expression. This was shown to be similar to the effects of p38 MAPK inhibitor (SB203580). Furthermore, luciferase assay results demonstrated that Mtdh represents the target of miR-30s. Transient transfection experiments, using miR-30 microRNA (miRNA) inhibitors, led to the increase in Mtdh expression and induced the apoptosis of MPC5, whereas the treatment with miR-30 miRNA mimics led to the reduction in Mtdh expression and apoptosis of HG-induced MPC5 cells in comparison with their respective controls. Our results demonstrate that Mtdh is a potent modulator of podocyte apoptosis, and that it represents the target of miR-30 miRNAs, facilitating podocyte apoptosis through the activation of HG-induced p38 MAPK-dependent pathway. PMID:27882943

A novel pre-clinical strategy for identifying cardiotoxic kinase inhibitors and mechanisms of cardiotoxicity

PubMed Central

Cheng, Hui; Kari, Gabor; Dicker, Adam P; Rodeck, Ulrich; Koch, Walter J; Force, Thomas

2011-01-01

Rationale 1) Despite intense interest in strategies to predict which kinase inhibitor (KI) cancer therapeutics may be associated with cardiotoxicity, current approaches are inadequate. 2) Sorafenib is a KI of concern since it inhibits growth factor receptors and Raf-1/B-Raf, kinases that are upstream of ERKs and signal cardiomyocyte survival in the setting of stress. Objectives 1) Explore the potential use of zebrafish as a pre-clinical model to predict cardiotoxicity. 2) Determine whether sorafenib has associated cardiotoxicity and, if so, define the mechanisms. Methods and Results We find that the zebrafish model is readily able to discriminate a KI with little or no cardiotoxicity (gefitinib) from one with demonstrated cardiotoxicity (sunitinib). Sorafenib, like sunitinib, leads to cardiomyocyte apoptosis, a reduction in total myocyte number per heart, contractile dysfunction and ventricular dilatation in zebrafish. In cultured rat cardiomyocytes, sorafenib induces cell death. This can be rescued by adenovirus-mediated gene transfer of constitutively active MEK1 which restores ERK activity even in the presence of sorafenib. While growth factor-induced activation of ERKs requires Raf, α-adrenergic agonist-induced activation of ERKs does not. Consequently, activation of α-adrenergic signaling markedly decreases sorafenib-induced cell death. Consistent with these in vitro data, inhibition of α-adrenergic signaling with the receptor antagonist prazosin worsens sorafenib-induced cardiomyopathy in zebrafish. Conclusions 1) Zebrafish may be a valuable pre-clinical tool to predict cardiotoxicity. 2) The α-adrenergic signaling pathway is an important modulator of sorafenib cardiotoxicity in vitro and in vivo and appears to act via a here-to-fore unrecognized signaling pathway downstream of α-adrenergic activation that bypasses Raf to activate ERKs. PMID:21998323

Aldose reductase is implicated in high glucose-induced oxidative stress in mouse embryonic neural stem cells.

PubMed

Fu, Jiang; Tay, S S W; Ling, E A; Dheen, S T

2007-11-01

Oxidative stress caused by hyperglycemia is one of the key factors responsible for maternal diabetes-induced congenital malformations, including neural tube defects in embryos. However, mechanisms by which maternal diabetes induces oxidative stress during neurulation are not clear. The present study was aimed to investigate whether high glucose induces oxidative stress in neural stem cells (NSCs), which compose the neural tube during development. We also investigated the mechanism by which high glucose disturbs the growth and survival of NSCs in vitro. NSCs were exposed to physiological d-glucose concentration (PG, 5 mmol/L), PG with l-glucose (25 mmol/L), or high d-glucose concentration (HG, 30 or 45 mmol/l). HG induced reactive oxygen species production and mRNA expression of aldose reductase (AR), which catalyzes the glucose reduction through polyol pathway, in NSCs. Expression of glucose transporter 1 (Glut1) mRNA and protein which regulates glucose uptake in NSCs was increased at early stage (24 h) and became down-regulated at late stage (72 h) of exposure to HG. Inhibition of AR by fidarestat, an AR inhibitor, decreased the oxidative stress, restored the cell viability and proliferation, and reduced apoptotic cell death in NSCs exposed to HG. Moreover, inhibition of AR attenuated the down-regulation of Glut1 expression in NSCs exposed to HG for 72 h. These results suggest that the activation of polyol pathway plays a role in the induction of oxidative stress which alters Glut1 expression and cell cycle in NSCs exposed to HG, thereby resulting in abnormal patterning of the neural tube in embryos of diabetic pregnancy.

Nitric-oxide synthase trafficking inducer is a pleiotropic regulator of endothelial cell function and signaling

PubMed Central

2017-01-01

Endothelial nitric-oxide synthase (eNOS) and its bioactive product, nitric oxide (NO), mediate many endothelial cell functions, including angiogenesis and vascular permeability. For example, vascular endothelial growth factor (VEGF)-mediated angiogenesis is inhibited upon reduction of NO bioactivity both in vitro and in vivo. Moreover, genetic disruption or pharmacological inhibition of eNOS attenuates angiogenesis during tissue repair, resulting in delayed wound closure. These observations emphasize that eNOS-derived NO can promote angiogenesis. Intriguingly, eNOS activity is regulated by nitric-oxide synthase trafficking inducer (NOSTRIN), which sequesters eNOS, thereby attenuating NO production. This has prompted significant interest in NOSTRIN's function in endothelial cells. We show here that NOSTRIN affects the functional transcriptome of endothelial cells by down-regulating several genes important for invasion and angiogenesis. Interestingly, the effects of NOSTRIN on endothelial gene expression were independent of eNOS activity. NOSTRIN also affected the expression of secreted cytokines involved in inflammatory responses, and ectopic NOSTRIN overexpression functionally restricted endothelial cell proliferation, invasion, adhesion, and VEGF-induced capillary tube formation. Furthermore, NOSTRIN interacted directly with TNF receptor-associated factor 6 (TRAF6), leading to the suppression of NFκB activity and inhibition of AKT activation via phosphorylation. Interestingly, TNF-α-induced NFκB pathway activation was reversed by NOSTRIN. We found that the SH3 domain of NOSTRIN is involved in the NOSTRIN-TRAF6 interaction and is required for NOSTRIN-induced down-regulation of endothelial cell proteins. These results have broad biological implications, as aberrant NOSTRIN expression leading to deactivation of the NFκB pathway, in turn triggering an anti-angiogenic cascade, might inhibit tumorigenesis and cancer progression. PMID:28235804

Ebselen suppresses inflammation induced by Helicobacter pylori lipopolysaccharide via the p38 mitogen-activated protein kinase signaling pathway.

PubMed

Xu, Ling; Gong, Changguo; Li, Guangming; Wei, Jue; Wang, Ting; Meng, Wenying; Shi, Min; Wang, Yugang

2018-05-01

Ebselen is a seleno-organic compound that has been demonstrated to have antioxidant and anti-inflammatory properties. A previous study determined that ebselen inhibits airway inflammation induced by inhalational lipopolysaccharide (LPS), however, the underlying molecular mechanism remains to be elucidated. The present study investigated the effect of ebselen on the glutathione peroxidase (GPX)‑reactive oxygen species (ROS) pathway and interleukin‑8 (IL‑8) expression induced by Helicobacter pylori LPS in gastric cancer (GC) cells. Cells were treated with 200 ng/ml H. pylori‑LPS in the presence or absence of ebselen for various durations and concentrations (µmol/l). The expression of toll‑like receptor 4 (TLR4), GPX2, GPX4, p38 mitogen‑activated protein kinase (p38 MAPK), phosphorylated‑p38 MAPK, ROS production and IL‑8 expression were detected with western blotting or ELISA. The present study revealed that TLR4 expression was upregulated; however, GPX2 and GPX4 expression was reduced following treatment with H. pylori LPS, which led to increased ROS production, subsequently altering the IL‑8 expression level in GC cells. Additionally, it was determined that ebselen prevented the reduction in GPX2/4 levels induced by H. pylori LPS, however, TLR4 expression was not affected. Ebselen may also block the expression of IL‑8 by inhibiting phosphorylation of p38 MAPK. These data suggest ebselen may inhibit ROS production triggered by H. pylori LPS treatment via GPX2/4 instead of TLR4 signaling and reduce phosphorylation of p38 MAPK, resulting in altered production of IL‑8. Ebselen may, therefore, be a potential therapeutic agent to mediate H. pylori LPS-induced cell damage.

Salsalate and adiponectin ameliorate hepatic steatosis by inhibition of the hepatokine fetuin-A.

PubMed

Jung, Tae Woo; Youn, Byung-Soo; Choi, Hae Yoon; Lee, So Young; Hong, Ho Cheol; Yang, Sae Jeong; Yoo, Hye Jin; Kim, Baek-Hui; Baik, Sei Hyun; Choi, Kyung Mook

2013-10-01

Fetuin-A was recently identified as a novel hepatokine which is associated with obesity, insulin resistance and non-alcoholic fatty liver disease. Salsalate, a prodrug of salicylate with an anti-inflammatory effect and lower side effect profile, significantly lowers glucose and triglyceride levels, and increased adiponectin concentrations in randomized clinical trials. In this study, we examined the effects and regulatory mechanisms of salsalate and full length-adiponectin (fAd) on fetuin-A expression, steatosis and lipid metabolism in palmitate-treated HepG2 cells. Incubation of hepatocytes with palmitate significantly increased fetuin-A and SREBP-1c expression which lead to steatosis and knock-down of fetuin-A by siRNA restored these changes. Salsalate significantly down-regulated palmitate-induced fetuin-A mRNA expression and secretion in a dose- and time-dependent manner. Inhibition of palmitate-induced fetuin-A by salsalate was mediated by AMPK-mediated reduction of NFκB activity, which was blocked by AMPK siRNA or an inhibitor of AMPK. Salsalate attenuated the excessive steatosis by palmitate through SREBP-1c regulation in hepatocytes. Furthermore, fAd also showed suppression of palmitate-induced fetuin-A through the AMPK pathway and improvement of steatosis accompanied by restoration of SREBP-1c, PAPR-α and CD36. In preliminary in vivo experiments, salsalate treatment inhibited high fat diet (HFD)-induced steatosis as well as fetuin-A mRNA and protein expression in SD rats. In conclusion, salsalate and fAd improved palmitate-induced steatosis and impairment of lipid metabolism in hepatocytes via fetuin-A inhibition through the AMPK-NFκB pathway. Copyright © 2013 Elsevier Inc. All rights reserved.

Tanshinone IIA inhibits AGEs-induced proliferation and migration of cultured vascular smooth muscle cells by suppressing ERK1/2 MAPK signaling.

PubMed

Lu, Ming; Luo, Ying; Hu, Pengfei; Dou, Liping; Huang, Shuwei

2018-01-01

Vascular smooth muscle cells (VSMCs) play a key role in the pathogenesis of diabetic vascular disease. Our current study sought to explore the effects of tanshinone IIA on the proliferation and migration of VSMCs induced by advanced glycation end products (AGEs). In this study, we examined the effects of tanshinone IIA by cell proliferation assay and cell migration assay. And we explored the underlying mechanism by Western blotting. AGEs significantly induced the proliferation and migration of VSMCs, but treatment with tanshinone IIA attenuated these effects. AGEs could increase the activity of the ERK1/2 and p38 pathways but not the JNK pathway. Treatment with tanshinone IIA inhibited the AGEs-induced activation of the ERK1/2 pathway but not the p38 pathway. Tanshinone IIA inhibits AGEs-induced proliferation and migration of VSMCs by suppressing the ERK1/2 MAPK signaling pathway.

Indole-3-Carbinol (I3C) enhances the sensitivity of murine breast adenocarcinoma cells to doxorubicin (DOX) through inhibition of NF-κβ, blocking angiogenesis and regulation of mitochondrial apoptotic pathway.

PubMed

Hajra, Subhadip; Patra, Arup Ranjan; Basu, Abhishek; Saha, Prosenjit; Bhattacharya, Sudin

2018-06-25

Various epidemiological and preclinical studies have already established the cancer chemopreventive potential of naturally occurring glucosinolate breakdown product Indole-3-Carbinol (I3C) as well as its abilities to induce selective cell death towards malignant cell. Therefore, the objective of the present study is to improve the therapeutic efficacy and prevention of doxorubicin (DOX)-induced toxicity, by the concurrent use of Indole-3-Carbinol (I3C). In this study, I3C was administered (20 mg/kg b.w., p.o.) to breast adenocarcinoma (Ehrlich ascites carcinoma) induced solid tumor bearing mice alone as well as in combination with DOX (5 mg/kg b.w., i.p.) in concomitant and pretreatment schedule. The results showed that concurrent administration of I3C and DOX significantly (P < 0.05) improved therapeutic efficacy as evidenced by reduction of tumor size and enhancement of host survivability. Oral administration of I3C significantly (P < 0.05) inhibited the expression of NF-κβ in both tumor cells and cardiac tissue as well as maximizes the therapeutic outcome in terms of tumor cell killing and toxicity. In addition, I3C sensitized tumor cells to DOX-therapy by down-regulating the expression of anti-apoptotic protein Bcl-2 and by up-regulating molecules like Bax, cytochrome c, caspases, which led to PARP cleavage and apoptosis. Significant inhibition of angiogenesis along with reduction in the serum levels of VEGF-A and MMP-9 further contribute to the sensitization accomplished by I3C. Moreover, we also found that I3C provided additional host survival advantages by attenuated DOX-induced toxicities through modulation of Nrf2/ARE pathway and promoted expression of cytoprotective proteins HO-1, NQO1 and GSTπ in cardiac tissue. In addition, I3C significantly attenuated DOX-induced inflammation by down-regulation of NF-kβ, iNOS, COX-2 and IL-6 in cardiac tissue. Thus, the present study clearly suggested therapeutic benefit of I3C in combination with DOX by augmenting anticancer efficacy and diminishing toxicity to the host. Copyright © 2018 Elsevier B.V. All rights reserved.

Detoxification of L-canavanine by the tobacco budworm, Heliothis virescens (Noctuidae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berge, M.A.; Rosenthal, G.A.

1990-11-01

The detoxification of L-canavanine and the ability of this natural product to induce a protein able to detoxify it were investigated in the tobacco budworm, Heliothis virescens. The available evidence indicates that this detoxification mechanism is part of larval constitutive metabolism and not induced in response to canavanine. H. virescens larvae, administered 5 mg/g L-canavanine supplemented with 37.7 kBq L-(guanidinooxy-{sup 14}C)canavanine, were sacrificied 0, 1, 2, 4, 6, and 12 h postinjection. The principle products of L-canavanine degradation were ({sup 14}C)guanidine and ({sup 14}C)urea. Homoserine formation was confirmed by automated amino acid analysis. This study demonstrates that the principal detoxificationmore » pathway for L-canavanine in H. virescens larvae is by reductive cleavage to guanidine and L-homoserine.« less

Unilateral dampening of Bmp activity by nodal generates cardiac left-right asymmetry.

PubMed

Veerkamp, Justus; Rudolph, Franziska; Cseresnyes, Zoltan; Priller, Florian; Otten, Cécile; Renz, Marc; Schaefer, Liliana; Abdelilah-Seyfried, Salim

2013-03-25

Signaling by Nodal and Bmp is essential for cardiac laterality. How activities of these pathways translate into left-right asymmetric organ morphogenesis is largely unknown. We show that, in zebrafish, Nodal locally reduces Bmp activity on the left side of the cardiac field. This effect is mediated by the extracellular matrix enzyme Hyaluronan synthase 2, expression of which is induced by Nodal. Unilateral reduction of Bmp signaling results in lower expression of nonmuscle myosin II and higher cell motility on the left, driving asymmetric displacement of the entire cardiac field. In silico modeling shows that left-right differences in cell motility are sufficient to induce a robust, directional migration of cardiac tissue. Thus, the mechanism underlying the formation of cardiac left-right asymmetry involves Nodal modulating an antimotogenic Bmp activity. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of Signaling Pathways Involved in γ-Globin Gene Induction Using Fetal Hemoglobin Inducer Drugs.

PubMed

Rahim, Fakher; Allahmoradi, Hossein; Salari, Fatemeh; Shahjahani, Mohammad; Fard, Ali Dehghani; Hosseini, Seyed Ahmad; Mousakhani, Hadi

2013-01-01

Potent induction of fetal hemoglobin (HbF) production results in alleviating the complications of β-thalassemia and sickle cell disease (SCD). HbF inducer agents can trigger several molecular signaling pathways critical for erythropoiesis. Janus kinase/Signal transducer and activator of transcription (JAK/STAT), mitogen activated protein kinas (MAPK) and Phosphoinositide 3-kinase (PI3K) are considered as main signaling pathways, which may play a significant role in HbF induction. All these signaling pathways are triggered by erythropoietin (EPO) as the main growth factor inducing erythroid differentiation, when it binds to its cell surface receptor, erythropoietin receptor (EPO-R) HbF inducer agents have been shown to upregulate HbF production level by triggering certain signaling pathways. As a result, understanding the pivotal signaling pathways influencing HbF induction leads to effective upregulation of HbF. In this mini review article, we try to consider the correlation between HbF inducer agents and their molecular mechanisms of γ-globin upregulation. Several studies suggest that activating P38 MAPK, RAS and STAT5 signaling pathways result in efficient HbF induction. Nevertheless, the role of other erythroid signaling pathways in HbF induction seems to be indispensible and should be emphasized.

Onset of diabetes modulates the airway smooth muscle reactivity of guinea pigs: role of epithelial mediators.

PubMed

Saidullah, Bano; Muralidhar, Kambadur; Fahim, Mohammad

2014-01-01

Diabetes induces lung dysfunction, leading to alteration in the pulmonary functions. Our aim was to investigate whether the early stage of diabetes alters the epithelium-dependent bronchial responses and whether nitric oxide (NO), KATP channels and cyclooxygenase (COX) pathways contribute in this effect. Guinea pigs were treated with a single injection of streptozotocin (180 mg/kg, i.p.) for induction of diabetes. Airway conductivity was assessed by inhaled histamine, using a non-invasive body plethysmography. The contractile responses of tracheal rings induced by acetylcholine (ACh) and relaxant responses of precontracted rings, induced by isoproterenol (IP) were compared in the presence and absence of the epithelium. Effects of N(ω)-Nitro-L-arginine methyl ester (L-NAME, a nitric oxide synthase inhibitor), glybenclamide (a KATP channel inhibitor) and indomethacin (a COX inhibitor) were also assessed in diabetic guinea pigs. Early stage diabetes did not alter the airway conductivity. ACh-induced bronchoconstriction in epithelium intact tracheal rings was not affected by the onset of diabetes, however a reduction in the increased ACh responses due to epithelium removal, to L-NAME or to indomethacin was observed. The relaxation response to IP was impaired in trachea from guinea pigs in which diabetes had just developed. Early diabetes significantly reduced the IP response to glybenclamide and to indomethacin. Our results demonstrate that the early stage of diabetes, modulate the bronchial reactivity to both ACh and IP by disrupting the NO, KATP channels and COX pathways, without affecting the airway conductivity in guinea pigs.

Chronic nandrolone administration induces dysfunction of the reward pathway in rats.

PubMed

Zotti, Margherita; Tucci, Paolo; Colaianna, Marilena; Morgese, Maria Grazia; Mhillaj, Emanuela; Schiavone, Stefania; Scaccianoce, Sergio; Cuomo, Vincenzo; Trabace, Luigia

2014-01-01

Data in animal models and surveys in humans have revealed psychiatric complications of long-term anabolic androgenic steroid abuse. However, the neurobiochemical mechanisms behind the observed behavioral changes are poorly understood. The aim of the present study was to investigate the effects of nandrolone decanoate on emotional behavior and neurochemical brain alterations in gonadally intact male rats. The behavioral reactivity to the elevated plus maze and the social interaction test was used to assess anxiety-related symptoms, and the sucrose preference test was used to evaluate anhedonia. Dopaminergic, serotonergic and noradrenergic transmissions were also evaluated in selected brain areas. The chronic administration of nandrolone, at 5 mg kg(-1) injected daily for 4 weeks, induced the loss of sweet taste preference, a sign of anhedonia and dysfunction of the reward pathway. The behavioral outcomes were accompanied by reductions in the dopamine, serotonin and noradrenaline contents in the nucleus accumbens. Alterations in the time spent in the open arms and in the social interaction test were not found, suggesting that nandrolone did not induce an anxiogenic profile. No differences were revealed between the experimental groups in the amygdala in terms of the neurotransmitters measured. Our data suggest that nandrolone-treated rats have a depressive, but not anxiogenic-like, profile, accompanied by brain region-dependent changes in dopaminergic, serotonergic and noradrenergic neurotransmission. As anabolic androgenic steroid dependence is plausibly the major form of worldwide substance dependence that remains largely unexplored, it should be highlighted that our data could contribute to a better understanding of the altered rewards induced by nandrolone treatment and to the development of appropriate treatments.

Sorbitol-modified hyaluronic acid reduces oxidative stress, apoptosis and mediators of inflammation and catabolism in human osteoarthritic chondrocytes.

PubMed

Mongkhon, John-Max; Thach, Maryane; Shi, Qin; Fernandes, Julio C; Fahmi, Hassan; Benderdour, Mohamed

2014-08-01

Our study was designed to elucidate the precise molecular mechanisms by which sorbitol-modified hyaluronic acid (HA/sorbitol) exerts beneficial effects in osteoarthritis (OA). Human OA chondrocytes were treated with increasing doses of HA/sorbitol ± anti-CD44 antibody or with sorbitol alone and thereafter with or without interleukin-1beta (IL-1β) or hydrogen peroxide (H2O2). Signal transduction pathways and parameters related to oxidative stress, apoptosis, inflammation, and catabolism were investigated. HA/sorbitol prevented IL-1β-induced oxidative stress, as measured by reactive oxygen species, p47-NADPH oxidase phosphorylation, 4-hydroxynonenal (HNE) production and HNE-metabolizing glutathione-S-transferase A4-4 expression. Moreover, HA/sorbitol stifled IL-1β-induced metalloproteinase-13, nitric oxide (NO) and prostaglandin E2 release as well as inducible NO synthase expression. Study of the apoptosis process revealed that this gel significantly attenuated cell death, caspase-3 activation and DNA fragmentation elicited by exposure to a cytotoxic H2O2 dose. Examination of signaling pathway components disclosed that HA/sorbitol prevented IL-1β-induced p38 mitogen-activated protein kinase and nuclear factor-kappa B activation, but not that of extracellular signal-regulated kinases 1 and 2. Interestingly, the antioxidant as well as the anti-inflammatory and anti-catabolic effects of HA/sorbitol were attributed to sorbitol and HA, respectively. Altogether, our findings support a beneficial effect of HA/sorbitol in OA through the restoration of redox status and reduction of apoptosis, inflammation and catabolism involved in cartilage damage.

Curcumin inhibits adipogenesis induced by benzyl butyl phthalate in 3T3-L1 cells.

PubMed

Sakuma, Satoru; Sumida, Maki; Endoh, Yukiko; Kurita, Ayaka; Yamaguchi, Ayana; Watanabe, Tomoki; Kohda, Tetsuya; Tsukiyama, Yui; Fujimoto, Yohko

2017-08-15

Phthalates are a group of endocrine disrupting chemicals and may have contributed to the recent global obesity health crisis. Increased adipogenesis via the peroxisome proliferator-activated receptor γ (PPARγ)-CCAAT-enhancer binding protein α (C/EBPα) pathway could be one critical mechanism responsible for phthalate-induced weight gain. On the other hand, curcumin has been shown to inhibit adipogenesis in cells and animal models. The present study was undertaken to evaluate, for the first time, whether curcumin could reduce adipogenesis induced by benzyl butyl phthalate (BBP) via downregulation of the PPARγ-C/EBPα pathway. 3T3-L1 preadipocytes were differentiated by treating them with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine in the presence of BBP, with or without curcumin. Cells that were grown in the presence of BBP alone showed a significant increase in triacylglycerol (TG) levels. In addition, the number of Oil Red O-stained cells and the mRNA expression levels of PPARγ, C/EBPα, adiponectin, and tumor necrosis factor-α (TNFα) were significantly increased. However, treatment with BBP in combination with curcumin resulted in major reductions in TG levels, the numbers of Oil Red O-stained cells, and the mRNA expression levels of the four proteins. These results suggest that curcumin might be an inhibitor of BBP-induced weight gain and inflammation via stimulation of adipocyte differentiation and TNFα generation. Curcumin may, therefore, be a potential medication for preventing the harmful effects of phthalates. Copyright © 2017 Elsevier Inc. All rights reserved.

Curcumin Anti-Apoptotic Action in a Model of Intestinal Epithelial Inflammatory Damage

PubMed Central

Loganes, Claudia; Lega, Sara; Bramuzzo, Matteo; Vecchi Brumatti, Liza; Piscianz, Elisa; Valencic, Erica; Tommasini, Alberto; Marcuzzi, Annalisa

2017-01-01

The purpose of this study is to determine if a preventive treatment with curcumin can protect intestinal epithelial cells from inflammatory damage induced by IFNγ. To achieve this goal we have used a human intestinal epithelial cell line (HT29) treated with IFNγ to undergo apoptotic changes that can reproduce the damage of intestinal epithelia exposed to inflammatory cytokines. In this model, we measured the effect of curcumin (curcuminoid from Curcuma Longa) added as a pre-treatment at different time intervals before stimulation with IFNγ. Curcumin administration to HT29 culture before the inflammatory stimulus IFNγ reduced the cell apoptosis rate. This effect gradually declined with the reduction of the curcumin pre-incubation time. This anti-apoptotic action by curcumin pre-treatment was paralleled by a reduction of secreted IL7 in the HT29 culture media, while there was no relevant change in the other cytokine levels. Even though curcumin pre-administration did not impact the activation of the NF-κB pathway, a slight effect on the phosphorylation of proteins in this inflammatory signaling pathway was observed. In conclusion, curcumin pre-treatment can protect intestinal cells from inflammatory damage. These results can be the basis for studying the preventive role of curcumin in inflammatory bowel diseases. PMID:28587282

Curcumin Anti-Apoptotic Action in a Model of Intestinal Epithelial Inflammatory Damage.

PubMed

Loganes, Claudia; Lega, Sara; Bramuzzo, Matteo; Vecchi Brumatti, Liza; Piscianz, Elisa; Valencic, Erica; Tommasini, Alberto; Marcuzzi, Annalisa

2017-06-06

The purpose of this study is to determine if a preventive treatment with curcumin can protect intestinal epithelial cells from inflammatory damage induced by IFNγ. To achieve this goal we have used a human intestinal epithelial cell line (HT29) treated with IFNγ to undergo apoptotic changes that can reproduce the damage of intestinal epithelia exposed to inflammatory cytokines. In this model, we measured the effect of curcumin (curcuminoid from Curcuma Longa ) added as a pre-treatment at different time intervals before stimulation with IFNγ. Curcumin administration to HT29 culture before the inflammatory stimulus IFNγ reduced the cell apoptosis rate. This effect gradually declined with the reduction of the curcumin pre-incubation time. This anti-apoptotic action by curcumin pre-treatment was paralleled by a reduction of secreted IL7 in the HT29 culture media, while there was no relevant change in the other cytokine levels. Even though curcumin pre-administration did not impact the activation of the NF-κB pathway, a slight effect on the phosphorylation of proteins in this inflammatory signaling pathway was observed. In conclusion, curcumin pre-treatment can protect intestinal cells from inflammatory damage. These results can be the basis for studying the preventive role of curcumin in inflammatory bowel diseases.

Apoptosis inducing factor gene depletion inhibits zearalenone-induced cell death in a goat Leydig cell line.

PubMed

Yang, Diqi; Jiang, Tingting; Lin, Pengfei; Chen, Huatao; Wang, Lei; Wang, Nan; Zhao, Fan; Tang, Keqiong; Zhou, Dong; Wang, Aihua; Jin, Yaping

2017-01-01

Zearalenone (ZEA) is a contaminant of human food and animal feedstuffs that causes health hazards. However, the signal pathways underlying ZEA toxicity remain elusive. The aims of this study were to determine which pathways are involved in ZEA-induced cell death and investigate the effect of apoptosis inducing factor (AIF) on cell death during ZEA treatment in the immortalized goat Leydig cell line hTERT-GLC. This study showed that ZEA-induced cell death in hTERT-GLCs works via endoplasmic reticulum (ER) stress, the caspase-dependent pathway, the caspase-independent pathway and autophagy. Recombinant lentiviral vectors were constructed to silence AIF expression in hTERT-GLCs. Flow cytometry results showed that knockdown of AIF diminished ZEA-induced cell apoptosis in hTERT-GLCs. Furthermore, we found AIF depletion down-regulated phosphoIRE1α, GRP78, CHOP and promoted the switch of LC3-I to LC3-II. Therefore, ZEA induces cytotoxicity in hTERT-GLCs via different pathways, while AIF-mediated signaling plays a critical role in ZEA-induced cell death in hTERT-GLCs. Copyright © 2016 Elsevier Inc. All rights reserved.

Calpain mediates AIF-regulated caspase-independent pathway in cisplatin-induced apoptosis

NASA Astrophysics Data System (ADS)

Liu, Lei; Xing, Da; Chen, Wei R.

2007-11-01

Mitochondrial apoptosis inducing factor (AIF) on activation can translocate to the nucleus and induce cell death via caspase-independent pathway in cisplatin-induced apoptosis. Yet the precise signal transduction pathway(s) which regulates AIF-induced apoptotic pathway still remains poorly understood. In this study, we investigated the molecular mechanism of AIF release and redistribution in cisplatin-induced apoptosis in living ASTC-a-1 cells, as assessed by real-time anlysis. Herein, We report that during cisplatin-induced apoptosis, calpain activation, as measured in intact cells by a fluorescent substrates, is an early event, taking place well before AIF release and caspase-3 activation. Confocal imaging of the cells transfected with AIF-GFP demonstrated that AIF release occurred about 9 h after cisplatin treatment. The event proceeded progressively over time, coinciding with a nuclear translocation and lasting for more than 2 hours. AIF release and redistribution were effectively inhibited in samples co-treated with calpeptin and PD150606, two selective calpain inhibitors. Therefore, our results clearly show the kinetics of AIF release and redistribution in cisplatin-induced apoptosis in living ASTC-a-1 cells, and calpain played a crucial role in these events.

Estimating Environmental Co-benefits of U.S. GHG Reduction Pathways Using the GCAM-USA Integrated Assessment Model

EPA Science Inventory

Previous studies have shown that mitigating climate change through curbing greenhouse gas (GHG) emissions can bring about substantial environmental co-benefits, such as for air quality and reductions in energy-related water demand. A variety of pathways are available for reducing...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Hai; Cheng, Tao; Goddard, William A.

Energy and environmental concerns demand development of more efficient and selective electrodes for electrochemical reduction of CO 2 to form fuels and chemicals. Since Cu is the only pure metal exhibiting reduction to form hydrocarbon chemicals, we focus here on the Cu (111) electrode. We present a methodology for density functional theory calculations to obtain accurate onset electrochemical potentials with explicit constant electrochemical potential and pH effects using implicit solvation. We predict the atomistic mechanisms underlying electrochemical reduction of CO, finding that (1) at acidic pH, the C 1 pathway proceeds through COH to CHOH to form CH 4 whilemore » C 2 (C 3) pathways are kinetically blocked; (2) at neutral pH, the C 1 and C 2 (C 3) pathways share the COH common intermediate, where the branch to C-C coupling is realized by a novel CO-COH pathway; and (3) at high pH, early C-C coupling through adsorbed CO dimerization dominates, suppressing the C 1 pathways by kinetics, thereby boosting selectivity for multi-carbon products.« less

The chemical biology of methanogenesis

NASA Astrophysics Data System (ADS)

Ferry, James G.

2010-12-01

Two distinct pathways account for most of the CH 4 produced in the majority of the diverse and vast anaerobic environments of Earth's biosphere by microbes that are classified in the Archaea domain of life: conversion of the methyl group of acetate to CH 4 in the aceticlastic pathway and reduction of CO 2 with electrons derived from H 2, formate or CO in the CO 2 reduction pathway. Minor, albeit ecologically important, amounts of CH 4 are produced by conversion of methylotrophic substrates methanol, methylamines and methyl sulfides. Although all pathways have terminal steps in common, they deviate in the initial steps leading to CH 4 and mechanisms for synthesizing ATP for growth. Hydrogen gas is the major reductant for CO 2-reducing methanogens in the deep subsurface, although H 2 is also utilized by CO 2-reducing microbes from the Bacteria domain that produce acetate for the aceticlastic methanogens. This review presents fundamentals of the two major CH 4-producing pathways with a focus on understanding the potential for biologically-produced CH 4 on Mars.

A standardized bark extract of Pinus pinaster Aiton (Pycnogenol®) attenuated chronic obstructive pulmonary disease via Erk-sp1 signaling pathway.

PubMed

Shin, Na-Rae; Ryu, Hyung-Won; Ko, Je-Won; Park, Ji-Won; Kwon, Ok-Kyoung; Oh, Sei-Ryang; Kim, Jong-Choon; Shin, In-Sik; Ahn, Kyung-Seop

2016-12-24

A standardized bark extract of Pinus pinaster Aiton (Pycnogenol ® ; PYC) used as an herbal medicine to treat various diseases in Europe and North America. This study evaluates the ability of PYC to inhibit chronic obstructive pulmonary disease (COPD) in the cigarette smoke extract (CSE)-stimulated human airway epithelial cell line NCI-H292 and in a cigarette smoke (CS) and lipopolysaccharide (LPS)-induced mouse model. To induce COPD, the mice intranasally received LPS on day 4 and were exposed to CS for 1h per day (total eight cigarettes per day) from days 1-7. The mice were administered PYC at a dose of 15mg/kg and 30mg/kg 1h before CS exposure. In the CSE-stimulated NCI-H292 cells, PYC significantly inhibited Erk phosphorylation, sp1 expression, MUC5AC, and pro-inflammatory cytokines in a concentration-dependent manner, as evidenced by a reduction in their mRNA levels. Co-treatment with PYC and Erk inhibitors markedly reduced the levels inflammatory mediators compared to only PYC-treatment. In the COPD mice model, PYC decreased the inflammatory cell count and the levels of pro-inflammatory cytokines in the broncho-alveolar lavage fluid compared with COPD mice. PYC attenuated the recruitment of inflammatory cells in the airways and decreased the expression levels of Erk phosphorylation and sp1. PYC also inhibited the expression of myeloperoxidase and matrix metalloproteinases-9 in lung tissue. Our results indicate that PYC inhibited the reduction in the inflammatory response in CSE-stimulated NCI-H292 cells and the COPD mouse model via the Erk-sp1 pathway. Therefore, we suggest that PYC has the potential to treat COPD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Pulling habits out of rats: adenosine 2A receptor antagonism in dorsomedial striatum rescues meth-amphetamine-induced deficits in goal-directed action.

PubMed

Furlong, Teri M; Supit, Alva S A; Corbit, Laura H; Killcross, Simon; Balleine, Bernard W

2017-01-01

Addiction is characterized by a persistent loss of behavioral control resulting in insensitivity to negative feedback and abnormal decision-making. Here, we investigated the influence of methamphetamine (METH)-paired contextual cues on decision-making in rats. Choice between goal-directed actions was sensitive to outcome devaluation in a saline-paired context but was impaired in the METH-paired context, a deficit that was also found when negative feedback was provided. Reductions in c-Fos-related immunoreactivity were found in dorsomedial striatum (DMS) but not dorsolateral striatum after exposure to the METH context suggesting this effect reflected a loss specifically in goal-directed control in the METH context. This reduction in c-Fos was localized to non-enkephalin-expressing neurons in the DMS, likely dopamine D1-expressing direct pathway neurons, suggesting a relative change in control by the D1-direct versus D2-indirect pathways originating in the DMS may have been induced by METH-context exposure. To test this suggestion, we infused the adenosine 2A receptor antagonist ZM241385 into the DMS prior to test to reduce activity in D2 neurons relative to D1 neurons in the hope of reducing the inhibitory output from this region of the striatum. We found that this treatment fully restored sensitivity to negative feedback in a test conducted in the METH-paired context. These results suggest that drug exposure alters decision-making by downregulation of the circuitry mediating goal-directed action, an effect that can be ameliorated by acute A 2A receptor inhibition in this circuit. © 2015 Society for the Study of Addiction.

Epidermal Growth Factor Receptor activation promotes ADA3 acetylation through the AKT-p300 pathway

PubMed Central

Srivastava, Shashank; Mohibi, Shakur; Mirza, Sameer; Band, Hamid; Band, Vimla

2017-01-01

ABSTRACT The ADA3 (Alteration/Deficiency in Activation 3) protein is an essential adaptor component of several Lysine Acetyltransferase (KAT) complexes involved in chromatin modifications. Previously, we and others have demonstrated a crucial role of ADA3 in cell cycle progression and in maintenance of genomic stability. Recently, we have shown that acetylation of ADA3 is key to its role in cell cycle progression. Here, we demonstrate that AKT activation downstream of Epidermal Growth Factor Receptor (EGFR) family proteins stimulation leads to phosphorylation of p300, which in turn promotes the acetylation of ADA3. Inhibition of upstream receptor tyrosine kinases (RTKs), HER1 (EGFR)/HER2 by lapatinib and the accompanying reduction of phospho-AKT levels led to a decrease in p300 phosphorylation and ADA3 protein levels. The p300/PCAF inhibitor garcinol also destabilized the ADA3 protein in a proteasome-dependent manner and an ADA3 mutant with K→R mutations exhibited a marked increase in half-life, consistent with opposite role of acetylation and ubiquitination of ADA3 on shared lysine residues. ADA3 knockdown led to cell cycle inhibitory effects, as well as apoptosis similar to those induced by lapatinib treatment of HER2+ breast cancer cells, as seen by accumulation of CDK inhibitor p27, reduction in mitotic marker pH3(S10), and a decrease in the S-phase marker PCNA, as well as the appearance of cleaved PARP. Taken together our results reveal a novel RTK-AKT-p300-ADA3 signaling pathway involved in growth factor-induced cell cycle progression. PMID:28759294

Deletion of Apoptosis Inhibitor of Macrophage (AIM)/CD5L Attenuates the Inflammatory Response and Infarct Size in Acute Myocardial Infarction.

PubMed

Nishikido, Toshiyuki; Oyama, Jun-ichi; Shiraki, Aya; Komoda, Hiroshi; Node, Koichi

2016-04-04

An excessive inflammatory response after myocardial infarction (MI) increases myocardial injury. The toll-like receptor (TLR)-4 is activated by the recognition of endogenous ligands and is proinflammatory when there is myocardial tissue injury. The apoptosis inhibitor of the macrophage (AIM) is known to provoke an efflux of saturated free fatty acids (FFA) due to lipolysis, which causes inflammation via the TLR-4 pathway. Therefore, this study investigated the hypothesis that AIM causes a proinflammatory response after MI. The left anterior descending coronary artery was ligated to induce MI in both AIM-knockout (AIM(-/-)) and wild-type (WT) mice. After 3 days, the inflammatory response from activation of the TLR-4/NFκB pathway was assessed, and infarct size was measured by staining with triphenyltetrazolium chloride. In addition, left ventricular remodeling was examined after 28 days. Although the area at risk was similar between AIM(-/-) and WT mice, the infarct size was significantly smaller in AIM(-/-) mice (P=0.02). The heart weight-to-body weight ratio and myocardial fibrosis were also decreased in the AIM(-/-) mice, and the 28-day survival rate was improved (P<0.01). With the reduction of plasma FFA in AIM(-/-) mice, myocardial IRAK4 and NFκB activity were decreased (all P<0.05). Moreover, there was a reduction in myeloperoxidase activity and inducible nitric oxide synthase as part of the inflammatory response (P<0.01, P=0.03, respectively). Furthermore, NFκB DNA-binding activation via TLR-4, neutrophil infiltration, and inflammatory mediators were decreased in AIM(-/-) mice. The deletion of AIM reduced the inflammatory response and infarct size and improved survival after myocardial infarction. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Glutamine supplementation stimulates protein-synthetic and inhibits protein-degradative signaling pathways in skeletal muscle of diabetic rats.

PubMed

Lambertucci, Adriana C; Lambertucci, Rafael H; Hirabara, Sandro M; Curi, Rui; Moriscot, Anselmo S; Alba-Loureiro, Tatiana C; Guimarães-Ferreira, Lucas; Levada-Pires, Adriana C; Vasconcelos, Diogo A A; Sellitti, Donald F; Pithon-Curi, Tania C

2012-01-01

In this study, we investigated the effect of glutamine (Gln) supplementation on the signaling pathways regulating protein synthesis and protein degradation in the skeletal muscle of rats with streptozotocin (STZ)-induced diabetes. The expression levels of key regulatory proteins in the synthetic pathways (Akt, mTOR, GSK3 and 4E-BP1) and the degradation pathways (MuRF-1 and MAFbx) were determined using real-time PCR and Western blotting in four groups of male Wistar rats; 1) control, non-supplemented with glutamine; 2) control, supplemented with glutamine; 3) diabetic, non-supplemented with glutamine; and 4) diabetic, supplemented with glutamine. Diabetes was induced by the intravenous injection of 65 mg/kg bw STZ in citrate buffer (pH 4.2); the non-diabetic controls received only citrate buffer. After 48 hours, diabetes was confirmed in the STZ-treated animals by the determination of blood glucose levels above 200 mg/dL. Starting on that day, a solution of 1 g/kg bw Gln in phosphate buffered saline (PBS) was administered daily via gavage for 15 days to groups 2 and 4. Groups 1 and 3 received only PBS for the same duration. The rats were euthanized, and the soleus muscles were removed and homogenized in extraction buffer for the subsequent measurement of protein and mRNA levels. The results demonstrated a significant decrease in the muscle Gln content in the diabetic rats, and this level increased toward the control value in the diabetic rats receiving Gln. In addition, the diabetic rats exhibited a reduced mRNA expression of regulatory proteins in the protein synthesis pathway and increased expression of those associated with protein degradation. A reduction in the skeletal muscle mass in the diabetic rats was observed and was alleviated partially with Gln supplementation. The data suggest that glutamine supplementation is potentially useful for slowing the progression of muscle atrophy in patients with diabetes.

Glutamine Supplementation Stimulates Protein-Synthetic and Inhibits Protein-Degradative Signaling Pathways in Skeletal Muscle of Diabetic Rats

PubMed Central

Lambertucci, Adriana C.; Lambertucci, Rafael H.; Hirabara, Sandro M.; Curi, Rui; Moriscot, Anselmo S.; Alba-Loureiro, Tatiana C.; Guimarães-Ferreira, Lucas; Levada-Pires, Adriana C.; Vasconcelos, Diogo A. A.; Sellitti, Donald F.; Pithon-Curi, Tania C.

2012-01-01

In this study, we investigated the effect of glutamine (Gln) supplementation on the signaling pathways regulating protein synthesis and protein degradation in the skeletal muscle of rats with streptozotocin (STZ)-induced diabetes. The expression levels of key regulatory proteins in the synthetic pathways (Akt, mTOR, GSK3 and 4E-BP1) and the degradation pathways (MuRF-1 and MAFbx) were determined using real-time PCR and Western blotting in four groups of male Wistar rats; 1) control, non-supplemented with glutamine; 2) control, supplemented with glutamine; 3) diabetic, non-supplemented with glutamine; and 4) diabetic, supplemented with glutamine. Diabetes was induced by the intravenous injection of 65 mg/kg bw STZ in citrate buffer (pH 4.2); the non-diabetic controls received only citrate buffer. After 48 hours, diabetes was confirmed in the STZ-treated animals by the determination of blood glucose levels above 200 mg/dL. Starting on that day, a solution of 1 g/kg bw Gln in phosphate buffered saline (PBS) was administered daily via gavage for 15 days to groups 2 and 4. Groups 1 and 3 received only PBS for the same duration. The rats were euthanized, and the soleus muscles were removed and homogenized in extraction buffer for the subsequent measurement of protein and mRNA levels. The results demonstrated a significant decrease in the muscle Gln content in the diabetic rats, and this level increased toward the control value in the diabetic rats receiving Gln. In addition, the diabetic rats exhibited a reduced mRNA expression of regulatory proteins in the protein synthesis pathway and increased expression of those associated with protein degradation. A reduction in the skeletal muscle mass in the diabetic rats was observed and was alleviated partially with Gln supplementation. The data suggest that glutamine supplementation is potentially useful for slowing the progression of muscle atrophy in patients with diabetes. PMID:23239980

Evidence for the activation of pyroptotic and apoptotic pathways in RPE cells associated with NLRP3 inflammasome in the rodent eye.

PubMed

Gao, Jiangyuan; Cui, Jing Z; To, Eleanor; Cao, Sijia; Matsubara, Joanne A

2018-01-12

Age-related macular degeneration (AMD) is a devastating eye disease causing irreversible vision loss in the elderly. Retinal pigment epithelium (RPE), the primary cell type that is afflicted in AMD, undergoes programmed cell death in the late stages of the disease. However, the exact mechanisms for RPE degeneration in AMD are still unresolved. The prevailing theories consider that each cell death pathway works independently and without regulation of each other. Building upon our previous work in which we induced a short burst of inflammasome activity in vivo, we now investigate the effects of prolonged inflammasome activity on RPE cell death mechanisms in rats. Long-Evans rats received three intravitreal injections of amyloid beta (Aβ), once every 4 days, and were sacrificed at day 14. The vitreous samples were collected to assess the levels of secreted cytokines. The inflammasome activity was evaluated by both immunohistochemistry and western blot. The types of RPE cell death mechanisms were determined using specific cell death markers and morphological characterizations. We found robust inflammasome activation evident by enhanced caspase-1 immunoreactivity, augmented NF-κB nuclear translocalization, increased IL-1β vitreal secretion, and IL-18 protein levels. Moreover, we observed elevated proteolytic cleavage of caspase-3 and gasdermin D, markers for apoptosis and pyroptosis, respectively, in RPE-choroid tissues. There was also a significant reduction in the anti-apoptotic factor, X-linked inhibitor of apoptosis protein, consistent with the overall changes of RPE cells. Morphological analysis showed phenotypic characteristics of pyroptosis including RPE cell swelling. Our data suggest that two cell death pathways, pyroptosis and apoptosis, were activated in RPE cells after exposure to prolonged inflammasome activation, induced by a drusen component, Aβ. The involvement of two distinct cell death pathways in RPE sheds light on the potential interplay between these pathways and provides insights on the future development of therapeutic strategies for AMD.

Neutrophils induce macrophage anti-inflammatory reprogramming by suppressing NF-κB activation.

PubMed

Marwick, John A; Mills, Ross; Kay, Oliver; Michail, Kyriakos; Stephen, Jillian; Rossi, Adriano G; Dransfield, Ian; Hirani, Nikhil

2018-06-04

Apoptotic cells modulate the function of macrophages to control and resolve inflammation. Here, we show that neutrophils induce a rapid and sustained suppression of NF-κB signalling in the macrophage through a unique regulatory relationship which is independent of apoptosis. The reduction of macrophage NF-κB activation occurs through a blockade in transforming growth factor β-activated kinase 1 (TAK1) and IKKβ activation. As a consequence, NF-κB (p65) phosphorylation is reduced, its translocation to the nucleus is inhibited and NF-κB-mediated inflammatory cytokine transcription is suppressed. Gene Set Enrichment Analysis reveals that this suppression of NF-κB activation is not restricted to post-translational modifications of the canonical NF-κB pathway, but is also imprinted at the transcriptional level. Thus neutrophils exert a sustained anti-inflammatory phenotypic reprogramming of the macrophage, which is reflected by the sustained reduction in the release of pro- but not anti- inflammatory cytokines from the macrophage. Together, our findings identify a novel apoptosis-independent mechanism by which neutrophils regulate the mediator profile and reprogramming of monocytes/macrophages, representing an important nodal point for inflammatory control.

Electroencephalographic evoked pain response is suppressed by spinal cord stimulation in complex regional pain syndrome: a case report.

PubMed

Hylands-White, Nicholas; Duarte, Rui V; Beeson, Paul; Mayhew, Stephen D; Raphael, Jon H

2016-12-01

Pain is a subjective response that limits assessment. The purpose of this case report was to explore how the objectivity of the electroencephalographic response to thermal stimuli would be affected by concurrent spinal cord stimulation. A patient had been implanted with a spinal cord stimulator for the management of complex regional pain syndrome of both hands for 8 years. Following ethical approval and written informed consent we induced thermal stimuli using the Medoc PATHWAY Pain & Sensory Evaluation System on the right hand of the patient with the spinal cord stimulator switched off and with the spinal cord stimulator switched on. The patient reported a clinically significant reduction in thermal induced pain using the numerical rating scale (71.4 % reduction) with spinal cord stimulator switched on. Analysis of electroencephalogram recordings indicated the occurrence of contact heat evoked potentials (N2-P2) with spinal cord stimulator off, but not with spinal cord stimulator on. This case report suggests that thermal pain can be reduced in complex regional pain syndrome patients with the use of spinal cord stimulation and offers objective validation of the reported outcomes with this treatment.

The calcineurin pathway links hyperpolarization (Kir2.1)-induced Ca2+ signals to human myoblast differentiation and fusion.

PubMed

Konig, Stéphane; Béguet, Anne; Bader, Charles R; Bernheim, Laurent

2006-08-01

In human myoblasts triggered to differentiate, a hyperpolarization, resulting from K+ channel (Kir2.1) activation, allows the generation of an intracellular Ca2+ signal. This signal induces an increase in expression/activity of two key transcription factors of the differentiation process, myogenin and MEF2. Blocking hyperpolarization inhibits myoblast differentiation. The link between hyperpolarization-induced Ca2+ signals and the four main regulatory pathways involved in myoblast differentiation was the object of this study. Of the calcineurin, p38-MAPK, PI3K and CaMK pathways, only the calcineurin pathway was inhibited when Kir2.1-linked hyperpolarization was blocked. The CaMK pathway, although Ca2+ dependent, is unaffected by changes in membrane potential or block of Kir2.1 channels. Concerning the p38-MAPK and PI3K pathways, their activity is present already in proliferating myoblasts and they are unaffected by hyperpolarization or Kir2.1 channel block. We conclude that the Kir2.1-induced hyperpolarization triggers human myoblast differentiation via the activation of the calcineurin pathway, which, in turn, induces expression/activity of myogenin and MEF2.

Vasorelaxant effect of formononetin in the rat thoracic aorta and its mechanisms.

PubMed

Zhao, Yan; Chen, Bai-Nian; Wang, Shou-Bao; Wang, Shao-Hua; Du, Guan-Hua

2012-01-01

The purpose of the present study was to investigate the effect of formononetin and the related mechanisms on isolated rat thoracic aorta. Formononetin concentration dependently relaxed aortic rings precontracted with norepinephrine (NE, 1 μM) or KCl (80 mM). Pretreatment with formononetin noncompetitively inhibited contractile responses of aortas to NE and KCl. The vasorelaxant effect of formononetin partially relied on intact endothelia, which was significantly attenuated by incubation with N(ω)-nitro-L-arginine methyl ester (100 μM). In endothelium-denuded rings, glibenclamide (10 μM) and tetraethylammonium (5 mM) showed slight reduction in the vasorelaxant effect of formononetin. Moreover, formononetin reduced NE-induced transient contraction in Ca²⁺-free solution and inhibited the vasocontraction induced by increasing external calcium in medium plus 80 mM KCl. Our results suggested that formononetin induced relaxation in rat aortic rings through an endothelium-dependent manner via nitric oxide synthesis pathway, and also involving an endothelium-independent vasodilatation by the blockade of Ca²⁺ channels. The opening of K⁺ channels might also be one of the mechanisms of formononetin-induced vasorelaxation.

Donor-derived, tolerogenic dendritic cells suppress immune rejection in the indirect allosensitization-dominant setting of corneal transplantation.

PubMed

Hattori, Takaaki; Saban, Daniel R; Emami-Naeini, Parisa; Chauhan, Sunil K; Funaki, Toshinari; Ueno, Hiroki; Dana, Reza

2012-04-01

Significant interest has been focused on the use of ex vivo-manipulated DCs to optimally induce transplant tolerance and promote allograft survival. Although it is understood that donor-derived, tolerogenic DCs suppress the direct pathway of allosensitization, whether such DCs can similarly suppress the indirect pathway remains unclear. We therefore used the murine model of corneal transplantation to address this, as these allografts are rejected in an indirect pathway-dominant manner. Interestingly, recipients administered with donor bone marrow-derived DCregs, generated via culturing with GM-CSF, IL-10, and TGF-β1, significantly prolonged survival of corneal allografts. Correspondingly, these recipients demonstrated a potent reduction in the frequency of indirectly allosensitized T cells, as determined by ELISPOT. Examination of DCregs relative to mDCs or iDCs showed a resistance to up-regulation of MHC-II and costimulatory molecules, as well as an impaired capacity to stimulate MLRs. In vivo, DCreg administration in corneal-allografted recipients led to inhibition of CD4(+)IFN-γ(+) T cell frequencies and an associated increase in Foxp3 expression in the Treg compartment. We conclude that donor-derived, tolerogenic DCs significantly suppress the indirect pathway, thereby identifying a novel regulatory mechanism for these cells in transplantation.

Donor-derived, tolerogenic dendritic cells suppress immune rejection in the indirect allosensitization-dominant setting of corneal transplantation

PubMed Central

Hattori, Takaaki; Saban, Daniel R.; Emami-naeini, Parisa; Chauhan, Sunil K.; Funaki, Toshinari; Ueno, Hiroki; Dana, Reza

2012-01-01

Significant interest has been focused on the use of ex vivo-manipulated DCs to optimally induce transplant tolerance and promote allograft survival. Although it is understood that donor-derived, tolerogenic DCs suppress the direct pathway of allosensitization, whether such DCs can similarly suppress the indirect pathway remains unclear. We therefore used the murine model of corneal transplantation to address this, as these allografts are rejected in an indirect pathway-dominant manner. Interestingly, recipients administered with donor bone marrow-derived DCregs, generated via culturing with GM-CSF, IL-10, and TGF-β1, significantly prolonged survival of corneal allografts. Correspondingly, these recipients demonstrated a potent reduction in the frequency of indirectly allosensitized T cells, as determined by ELISPOT. Examination of DCregs relative to mDCs or iDCs showed a resistance to up-regulation of MHC-II and costimulatory molecules, as well as an impaired capacity to stimulate MLRs. In vivo, DCreg administration in corneal-allografted recipients led to inhibition of CD4+IFN-γ+ T cell frequencies and an associated increase in Foxp3 expression in the Treg compartment. We conclude that donor-derived, tolerogenic DCs significantly suppress the indirect pathway, thereby identifying a novel regulatory mechanism for these cells in transplantation. PMID:22291211

Voluntary Running Suppresses Tumor Growth through Epinephrine- and IL-6-Dependent NK Cell Mobilization and Redistribution.

PubMed

Pedersen, Line; Idorn, Manja; Olofsson, Gitte H; Lauenborg, Britt; Nookaew, Intawat; Hansen, Rasmus Hvass; Johannesen, Helle Hjorth; Becker, Jürgen C; Pedersen, Katrine S; Dethlefsen, Christine; Nielsen, Jens; Gehl, Julie; Pedersen, Bente K; Thor Straten, Per; Hojman, Pernille

2016-03-08

Regular exercise reduces the risk of cancer and disease recurrence. Yet the mechanisms behind this protection remain to be elucidated. In this study, tumor-bearing mice randomized to voluntary wheel running showed over 60% reduction in tumor incidence and growth across five different tumor models. Microarray analysis revealed training-induced upregulation of pathways associated with immune function. NK cell infiltration was significantly increased in tumors from running mice, whereas depletion of NK cells enhanced tumor growth and blunted the beneficial effects of exercise. Mechanistic analyses showed that NK cells were mobilized by epinephrine, and blockade of β-adrenergic signaling blunted training-dependent tumor inhibition. Moreover, epinephrine induced a selective mobilization of IL-6-sensitive NK cells, and IL-6-blocking antibodies blunted training-induced tumor suppression, intratumoral NK cell infiltration, and NK cell activation. Together, these results link exercise, epinephrine, and IL-6 to NK cell mobilization and redistribution, and ultimately to control of tumor growth. Copyright © 2016 Elsevier Inc. All rights reserved.