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Sample records for inhibitors induce peroxisome

  1. Proteasome inhibitors induce peroxisome proliferator-activated receptor transactivation through RXR accumulation and a protein kinase C-dependent pathway

    SciTech Connect

    Tsao, W.-C.; Wu, H.-M.; Chi, K.-H.; Chang, Y.-H.; Lin, W.-W. . E-mail: wwl@ha.mc.ntu.edu.tw

    2005-03-10

    Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}), a member of nuclear hormone receptors, forms a heterodimeric DNA binding complex with retinoid X receptor (RXR) and serves as a transcriptional regulator of gene expression. In this study, using luciferase assay of a reporter gene containing PPAR response element (PPRE), we found PPRE transactivity was additively induced by PPAR{gamma} activator (15dPGJ{sub 2}) and RXR activator (9-cis retinoic acid, 9-cis RA). Proteasome inhibitors MG132 and MG262 also stimulate PPRE transactivity in a concentration-dependent manner, and this effect is synergistic to 15dPGJ{sub 2} and 9-cis RA. PKC activation by 12-myristate 13-acetate (PMA) and ingenol 3,20-dibenzoate (IDB) also led to an increased PPRE activation, and this action was additive to PPAR{gamma} activators and 9-cis RA, but not to proteasome inhibitors. Results indicate that the PPAR{gamma} enhancing effect of proteasome inhibitors was attributed to redox-sensitive PKC activation. Western blot analysis showed that the protein level of RXR{alpha}, but not PPAR{gamma}, RXR{beta}, or PKC isoforms, was accumulated in the presence of proteasome inhibitors. Taken together, we conclude that proteasome inhibitors can upregulate PPRE activity through RXR{alpha} accumulation and a PKC-dependent pathway. The former is due to inhibition of RXR{alpha} degradation through ubiquitin-dependent proteasome system, while the latter is mediated by reactive oxygen species (ROS) production.

  2. Dysfunction of peroxisomes in twitcher mice brain: A possible mechanism of psychosine-induced disease

    SciTech Connect

    Haq, Ehtishamul; Contreras, Miguel A.; Giri, Shailendra; Singh, Inderjit; Singh, Avtar K. . E-mail: singha@musc.edu

    2006-04-28

    Psychosine (galactosylsphingosine) accumulates in Brain of Krabbe disease (KD) patients as well as twitcher mice, a murine model of KD, resulting in loss of oligodendrocytes and myelin. This study documents progressive loss of peroxisomal proteins/functions and induction of expression of inflammatory cytokine TNF-{alpha} in twitcher brain. The observed decrease in peroxisomal proteins was accompanied by decreased level of peroxisome proliferator-activated receptor-alpha (PPAR-{alpha}), one of the transcription factors required for expression of peroxisomal protein genes. The role of psychosine in down-regulation of PPAR-{alpha} activity was further supported by decreased PPAR-{alpha} mediated PPRE transcriptional activity in cells transfected with PPAR-{alpha} and PPRE reporters. The psychosine-induced down-regulation of PPAR activity and cell death was attenuated by sPLA{sub 2} inhibitor. Therefore, this study provides First evidence of peroxisomal abnormality in a lysosomal disorder, suggesting that such dysfunction of peroxisomes may play a role in the pathogenesis of Krabbe disease.

  3. Peroxisomal fatty acid oxidation and inhibitors of the mitochondrial carnitine palmitoyltransferase I in isolated rat hepatocytes.

    PubMed Central

    Skorin, C; Necochea, C; Johow, V; Soto, U; Grau, A M; Bremer, J; Leighton, F

    1992-01-01

    Fatty acid oxidation was studied in the presence of inhibitors of carnitine palmitoyltransferase I (CPT I), in normal and in peroxisome-proliferated rat hepatocytes. The oxidation decreased in mitochondria, as expected, but in peroxisomes it increased. These two effects were seen, in variable proportions, with (+)-decanoylcarnitine, 2-tetradecylglycidic acid (TDGA) and etomoxir. The decrease in mitochondrial oxidation (ketogenesis) affected saturated fatty acids with 12 or more carbon atoms, whereas the increase in peroxisomal oxidation (H2O2 production) affected saturated fatty acids with 8 or more carbon atoms. The peroxisomal increase was sensitive to chlorpromazine, a peroxisomal inhibitor. To study possible mechanisms, palmitoyl-, octanoyl- and acetyl-carnitine acyltransferase activities were measured, in homogenates and in subcellular fractions from control and TDGA-treated cells. The palmitoylcarnitine acyltransferase was inhibited, as expected, but the octanoyltransferase activity also decreased. The CoA derivative of TDGA was synthesized and tentatively identified as being responsible for inhibition of the octanoylcarnitine acyltransferase. These results show that inhibitors of the mitochondrial CPT I may also inhibit the peroxisomal octanoyl transferase; they also support the hypothesis that the octanoyltransferase has the capacity to control or regulate peroxisomal fatty acid oxidation. PMID:1736904

  4. ATM functions at the peroxisome to induce pexophagy in response to ROS.

    PubMed

    Zhang, Jiangwei; Tripathi, Durga Nand; Jing, Ji; Alexander, Angela; Kim, Jinhee; Powell, Reid T; Dere, Ruhee; Tait-Mulder, Jacqueline; Lee, Ji-Hoon; Paull, Tanya T; Pandita, Raj K; Charaka, Vijaya K; Pandita, Tej K; Kastan, Michael B; Walker, Cheryl Lyn

    2015-10-01

    Peroxisomes are highly metabolic, autonomously replicating organelles that generate reactive oxygen species (ROS) as a by-product of fatty acid ?-oxidation. Consequently, cells must maintain peroxisome homeostasis, or risk pathologies associated with too few peroxisomes, such as peroxisome biogenesis disorders, or too many peroxisomes, inducing oxidative damage and promoting diseases such as cancer. We report that the PEX5 peroxisome import receptor binds ataxia-telangiectasia mutated (ATM) and localizes this kinase to the peroxisome. In response to ROS, ATM signalling activates ULK1 and inhibits mTORC1 to induce autophagy. Specificity for autophagy of peroxisomes (pexophagy) is provided by ATM phosphorylation of PEX5 at Ser 141, which promotes PEX5 monoubiquitylation at Lys 209, and recognition of ubiquitylated PEX5 by the autophagy adaptor protein p62, directing the autophagosome to peroxisomes to induce pexophagy. These data reveal an important new role for ATM in metabolism as a sensor of ROS that regulates pexophagy. PMID:26344566

  5. Peroxisomal Biogenesis in Ischemic Brain

    PubMed Central

    Young, Jennifer M.; Nelson, Jonathan W.; Cheng, Jian; Zhang, Wenri; Mader, Sarah; Davis, Catherine M.; Morrison, Richard S.

    2015-01-01

    Abstract Aims: Peroxisomes are highly adaptable and dynamic organelles, adjusting their size, number, and enzyme composition to changing environmental and metabolic demands. We determined whether peroxisomes respond to ischemia, and whether peroxisomal biogenesis is an adaptive response to cerebral ischemia. Results: Focal cerebral ischemia induced peroxisomal biogenesis in peri-infarct neurons, which was associated with a corresponding increase in peroxisomal antioxidant enzyme catalase. Peroxisomal biogenesis was also observed in primary cultured cortical neurons subjected to ischemic insult induced by oxygen-glucose deprivation (OGD). A catalase inhibitor increased OGD-induced neuronal death. Moreover, preventing peroxisomal proliferation by knocking down dynamin-related protein 1 (Drp1) exacerbated neuronal death induced by OGD, whereas enhancing peroxisomal biogenesis pharmacologically using a peroxisome proliferator-activated receptor-alpha agonist protected against neuronal death induced by OGD. Innovation: This is the first documentation of ischemia-induced peroxisomal biogenesis in mammalian brain using a combined in vivo and in vitro approach, electron microscopy, high-resolution laser-scanning confocal microscopy, and super-resolution structured illumination microscopy. Conclusion: Our findings suggest that neurons respond to ischemic injury by increasing peroxisome biogenesis, which serves a protective function, likely mediated by enhanced antioxidant capacity of neurons. Antioxid. Redox Signal. 22, 109120. PMID:25226217

  6. Expression level of methanol-inducible peroxisomal proteins and peroxisome morphology are affected by oxygen conditions and mitochondrial respiratory pathway function in the methylotrophic yeast Candida boidinii.

    PubMed

    Fujimura, Shuki; Yurimoto, Hiroya; Kurimoto, Shota; Matsufuji, Yoshimi; Ito, Takashi; Hayakawa, Takashi; Tomizuka, Noboru; Sakai, Yasuyoshi; Nakagawa, Tomoyuki

    2013-06-01

    In the methylotrophic yeast, Candida boidinii, methanol-inducible peroxisomal proteins, for example alcohol oxidase (AOD), dihydroxyacetone synthase (DAS), and peroxisomal glutathione peroxidase (Pmp20), were induced only under aerobic conditions, while expression of PMP47 encoding peroxisomal integral membrane protein Pmp47 was independent of oxygen conditions. Expression of the methanol-inducible peroxisomal enzymes was repressed by inhibition of the mitochondrial respiratory chain. In the respiratory-deficient (?0) mutant strain, their induction was at very low levels despite the presence of oxygen, whereas the expression of PMP47 was unaffected. Taken together, these facts indicate that C. boidinii can sense oxygen conditions, and that mitochondrial respiratory function may have a profound effect on induction of methanol-inducible gene expression of peroxisomal proteins. Peroxisome morphology was also affected by oxygen conditions and respiratory function. Under hypoxic conditions or respiration-inhibited conditions, cells induced by methanol contained small peroxisomes, indicating that peroxisome biogenesis and the protein import machinery were not affected by oxygen conditions but that peroxisome morphology was dependent on induction of peroxisomal matrix proteins. PMID:23448597

  7. Endothelial Peroxisomal Dysfunction and Impaired Pexophagy Promotes Oxidative Damage in Lipopolysaccharide-Induced Acute Kidney Injury

    PubMed Central

    Ratliff, Brian B.; Bohr, Stefan; Nadel, Ellen; Chen, Jun; Xavier, Sandhya; Chander, Praveen; Goligorsky, Michael S.

    2013-01-01

    Abstract Aims: We examined that (a) how the endotoxic stress affects peroxisomal function and autophagic degradation of peroxisomespexophagy, (b) how a superimposed dysfunction of lysosomes and pexophagy modifies responses to lipopolysaccharide (LPS), and (c) the mechanisms of peroxisomal contribution to renal injury. To accomplish this, we used lysosome-defective Lyst-mice in vivo and primary endothelial cells in vitro, and compared the responses with wild-type (WT) littermates. Results: LPS induced pexophagic degradation, followed by proliferation of peroxisomes in WT mice, which was abolished in Lyst-mice. Lyst-mice exhibited impaired activation of catalase, which together with preserved hydrogen peroxide-generating ?-oxidation resulted in redox disequilibrium. LPS treatment induced a heightened inflammatory response, increased oxidative damage, and aggravated renal injury in Lyst-mice. Similarly, as in vivo, LPS-activated lysosomal (LYS) pexophagy and transiently repressed peroxisomes in vitro, supported by reduced peroxisomal density in the vicinity of lysosomes. Peroxisomal dynamics was also abolished in lysosome-defective cells, which accumulated peroxisomes with compromised functions and intraorganellar redox imbalance. Innovation: We demonstrated that pexophagy is a default response to endotoxic injury. However, when LYS dysfunction (a frequent companion of chronic diseases) is superimposed, recycling and functioning of peroxisomes are impaired, and an imbalance between hydrogen peroxide-generating ?-oxidation and hydrogen peroxide-detoxifying catalase ensues, which ultimately results in peroxisomal burnout. Conclusion: Our data strongly suggest that pexophagy, a cellular mechanism per se, is essential in functional maintenance of peroxisomes during LPS exposure. Inhibition of pexophagy results in accumulation of impaired peroxisomes, redox disequilibrium, and aggravated renal damage. Antioxid. Redox Signal. 19, 211230. PMID:23088293

  8. Plant peroxisomes are degraded by starvation-induced and constitutive autophagy in tobacco BY-2 suspension-cultured cells

    PubMed Central

    Voitsekhovskaja, Olga V.; Schiermeyer, Andreas; Reumann, Sigrun

    2014-01-01

    Very recently, autophagy has been recognized as an important degradation pathway for quality control of peroxisomes in Arabidopsis plants. To further characterize the role of autophagy in plant peroxisome degradation, we generated stable transgenic suspension-cultured cell lines of heterotrophic Nicotiana tabacum L. cv. Bright Yellow 2 expressing a peroxisome-targeted version of enhanced yellow fluorescent protein. Indeed, this cell line model system proved advantageous for detailed cytological analyses of autophagy stages and for quantification of cellular peroxisome pools under different culturing conditions and upon inhibitor applications. Complementary biochemical, cytological, and pharmacological analyses provided convincing evidence for peroxisome degradation by bulk autophagy during carbohydrate starvation. This degradation was slowed down by the inhibitor of autophagy, 3-methyladenine (3-MA), but the 3-MA effect ceased at advanced stages of starvation, indicating that another degradation mechanism for peroxisomes might have taken over. 3-MA also caused an increase particularly in peroxisomal proteins and cellular peroxisome numbers when applied under nutrient-rich conditions in the logarithmic growth phase, suggesting a high turnover rate for peroxisomes by basal autophagy under non-stress conditions. Together, our data demonstrate that a great fraction of the peroxisome pool is subject to extensive autophagy-mediated turnover under both nutrient starvation and optimal growth conditions. Our analyses of the cellular pool size of peroxisomes provide a new tool for quantitative investigations of the role of plant peroxisomes in reactive oxygen species metabolism. PMID:25477890

  9. PPAR? Activation Induces N?-Lys-Acetylation of Rat Liver Peroxisomal Multifunctional Enzyme Type 1

    PubMed Central

    Contreras, Miguel A.; Alzate, Oscar; Singh, Avtar K.

    2013-01-01

    Peroxisomes are ubiquitous subcellular organelles that participate in metabolic and disease processes, with few of its proteins undergoing posttranslational modifications. As the role of lysine-acetylation has expanded into the cellular intermediary metabolism, we used a combination of differential centrifugation, organelle isolation by linear density gradient centrifugation, western blot analysis, and peptide fingerprinting and amino acid sequencing by mass spectrometry to investigate protein acetylation in control and ciprofibrate-treated rat liver peroxisomes. Organelle protein samples isolated by density gradient centrifugation from PPAR?-agonist treated rat liver screened with an anti-N?-acetyl lysine antibody revealed a single protein band of 75 kDa. Immunoprecipitation with this antibody resulted in the precipitation of a protein from the protein pool of ciprofibrate-induced peroxisomes, but not from the protein pool of non-induced peroxisomes. Peptide mass fingerprinting analysis identified the protein as the peroxisomal multifunctional enzyme type 1. In addition, mass spectrometry-based amino acid sequencing resulted in the identification of unique peptides containing 4 acetylated-Lys residues (K155, K173, K190, and K583). This is the first report that demonstrates posttranslational acetylation of a peroxisomal enzyme in PPAR?-dependent proliferation of peroxisomes in rat liver. PMID:24092543

  10. Antioxidants attenuate diabetes-induced activation of peroxisomal functions in the rat kidney.

    PubMed

    Dhaunsi, Gursev S; Bitar, Milad S

    2004-01-01

    Diabetes is a multifactorial disease that has now been recognized to involve overproduction of reactive oxygen species and pro-inflammatory cytokines. Peroxisomes are subcellular organelles with several important metabolic functions, and their role in the regulation of cellular oxidative stress is now well established. Despite having their own antioxidant system, peroxisomes undergo functional alterations during various conditions that are associated with free radical production such as inflammation, ischemia-reperfusion, carcinogenesis and diabetes. In this study we investigated the effect of diabetes on peroxisomal functions in rat kidneys and show for the first time that experimental diabetes induces redox-sensitive enhancement of peroxisomal activities. Streptozotocin-induced diabetes significantly increased (p < 0.01) beta-oxidation of lignoceric acid and the enzymic activity of acyl coenzyme A oxidase. Catalase activity was significantly reduced (p < 0.01) in the kidneys of diabetic rats, whereas the enzymic activity of DHAPATase (dihydroxyacetone phosphate acyltransferase) was not markedly affected by diabetes. Treatment of diabetic rats with antioxidants, thiocetic acid and vitamin C attenuated the diabetes-induced modulation of peroxisomal functions. The present study shows that the diabetes-induced effects on kidney peroxisomal functions are redox sensitive, and antioxidants might prove useful tools to alleviate nephropathy in diabetes. PMID:15316130

  11. Pexophagy is induced by increasing peroxisomal reactive oxygen species in 1'10-phenanthroline-treated cells.

    PubMed

    Jo, Doo Sin; Bae, Dong-Jun; Park, So Jung; Seo, Hae Mi; Kim, Han Byeol; Oh, Jeong Su; Chang, Jong Wook; Kim, Sang-Yeob; Shin, Jung-Won; Cho, Dong-Hyung

    2015-11-13

    Although autophagy regulates the quality and quantity of cellular organelles, the regulatory mechanisms of peroxisomal autophagy remain largely unknown. In this study, we developed a cell-based image screening assay, and identified 1,10-phenanthroline (Phen) as a novel pexophagy inducer from chemical library screening. Treatment with Phen induces selective loss of peroxisomes but not endoplasmic reticulum and Golgi apparatus in hepatocytes. In addition, Phen increases autophagic engulfment of peroxisomes in an ATG5 dependent manner. Interestingly, treatment of Phen excessively produces peroxisomal reactive oxygen species (ROS), and inhibition of the ROS suppresses loss of peroxisome in Phen-treated cells. Taken together, these results suggest that Phen triggers pexophagy by enhancing peroxisomal ROS. PMID:26453011

  12. Identification and Characterization of a Stress-Inducible and a Constitutive Small Heat-Shock Protein Targeted to the Matrix of Plant Peroxisomes1[W

    PubMed Central

    Ma, Changle; Haslbeck, Martin; Babujee, Lavanya; Jahn, Olaf; Reumann, Sigrun

    2006-01-01

    Small heat-shock proteins (sHsps) are widespread molecular chaperones for which a peroxisomal localization has not yet been reported. The Arabidopsis (Arabidopsis thaliana) genome encodes two sHsps with putative peroxisomal targeting signals type 1 or 2 (PTS1 or PTS2). As demonstrated by double-labeling experiments using full-length fusion proteins with enhanced yellow fluorescent protein and deletion constructs lacking the putative targeting domains, AtHsp15.7 (At5g37670) and AtAcd31.2 (At1g06460) are targeted to the peroxisome matrix by a functional PTS1 (SKL>) and a functional PTS2 (RLx5HF), respectively. The peroxisomal localization of AtAcd31.2 was further confirmed by isolation of leaf peroxisomes from Arabidopsis by two successive sucrose density gradients, protein separation by one- and two-dimensional gel electrophoresis, and mass spectrometric protein identification. When AtHsp15.7 and AtAcd31.2 were heterologously expressed in yeast (Saccharomyces cerevisiae) and directed to the cytosol by deletion of the PTSs, both sHsps were able to complement the morphological phenotype of yeast mutants deficient in the cytosolic homologs ScHsp42 or ScHsp26. According to expression studies by reverse transcription-PCR, AtAcd31.2 is constitutively expressed, whereas AtHsp15.7 is hardly expressed under normal conditions but strongly induced by heat and oxidative stress, the latter of which was triggered by the catalase inhibitor 3-aminotriazole or the herbicide methyl viologen applied by watering of whole plants or infiltration of rosette leaves. Thus, plants are exceptional among eukaryotes in employing sHsps in the peroxisome matrix to prevent unspecific aggregation of partially denatured proteins under both physiological and stress conditions. PMID:16531488

  13. Compromised peroxisomes in idiopathic pulmonary fibrosis, a vicious cycle inducing a higher fibrotic response via TGF-? signaling

    PubMed Central

    Oruqaj, Gani; Karnati, Srikanth; Vijayan, Vijith; Boateng, Eistine; Zhang, Wenming; Ruppert, Clemens; Gnther, Andreas; Shi, Wei; Baumgart-Vogt, Eveline

    2015-01-01

    Idiopathic pulmonary fibrosis (IPF) is a devastating disease, and its pathogenic mechanisms remain incompletely understood. Peroxisomes are known to be important in ROS and proinflammatory lipid degradation, and their deficiency induces liver fibrosis. However, altered peroxisome functions in IPF pathogenesis have never been investigated. By comparing peroxisome-related protein and gene expression in lung tissue and isolated lung fibroblasts between human control and IPF patients, we found that IPF lungs exhibited a significant down-regulation of peroxisomal biogenesis and metabolism (e.g., PEX13p and acyl-CoA oxidase 1). Moreover, in vivo the bleomycin-induced down-regulation of peroxisomes was abrogated in transforming growth factor beta (TGF-?) receptor II knockout mice indicating a role for TGF-? signaling in the regulation of peroxisomes. Furthermore, in vitro treatment of IPF fibroblasts with the profibrotic factors TGF-?1 or tumor necrosis factor alpha (TNF-?) was found to down-regulate peroxisomes via the AP-1 signaling pathway. Therefore, the molecular mechanisms by which reduced peroxisomal functions contribute to enhanced fibrosis were further studied. Direct down-regulation of PEX13 by RNAi induced the activation of Smad-dependent TGF-? signaling accompanied by increased ROS production and resulted in the release of cytokines (e.g., IL-6, TGF-?) and excessive production of collagen I and III. In contrast, treatment of fibroblasts with ciprofibrate or WY14643, PPAR-? activators, led to peroxisome proliferation and reduced the TGF-?induced myofibroblast differentiation and collagen protein in IPF cells. Taken together, our findings suggest that compromised peroxisome activity might play an important role in the molecular pathogenesis of IPF and fibrosis progression, possibly by exacerbating pulmonary inflammation and intensifying the fibrotic response in the patients. PMID:25848047

  14. Compromised peroxisomes in idiopathic pulmonary fibrosis, a vicious cycle inducing a higher fibrotic response via TGF-? signaling.

    PubMed

    Oruqaj, Gani; Karnati, Srikanth; Vijayan, Vijith; Kotarkonda, Lakshmi Kanth; Boateng, Eistine; Zhang, Wenming; Ruppert, Clemens; Gnther, Andreas; Shi, Wei; Baumgart-Vogt, Eveline

    2015-04-21

    Idiopathic pulmonary fibrosis (IPF) is a devastating disease, and its pathogenic mechanisms remain incompletely understood. Peroxisomes are known to be important in ROS and proinflammatory lipid degradation, and their deficiency induces liver fibrosis. However, altered peroxisome functions in IPF pathogenesis have never been investigated. By comparing peroxisome-related protein and gene expression in lung tissue and isolated lung fibroblasts between human control and IPF patients, we found that IPF lungs exhibited a significant down-regulation of peroxisomal biogenesis and metabolism (e.g., PEX13p and acyl-CoA oxidase 1). Moreover, in vivo the bleomycin-induced down-regulation of peroxisomes was abrogated in transforming growth factor beta (TGF-?) receptor II knockout mice indicating a role for TGF-? signaling in the regulation of peroxisomes. Furthermore, in vitro treatment of IPF fibroblasts with the profibrotic factors TGF-?1 or tumor necrosis factor alpha (TNF-?) was found to down-regulate peroxisomes via the AP-1 signaling pathway. Therefore, the molecular mechanisms by which reduced peroxisomal functions contribute to enhanced fibrosis were further studied. Direct down-regulation of PEX13 by RNAi induced the activation of Smad-dependent TGF-? signaling accompanied by increased ROS production and resulted in the release of cytokines (e.g., IL-6, TGF-?) and excessive production of collagen I and III. In contrast, treatment of fibroblasts with ciprofibrate or WY14643, PPAR-? activators, led to peroxisome proliferation and reduced the TGF-?-induced myofibroblast differentiation and collagen protein in IPF cells. Taken together, our findings suggest that compromised peroxisome activity might play an important role in the molecular pathogenesis of IPF and fibrosis progression, possibly by exacerbating pulmonary inflammation and intensifying the fibrotic response in the patients. PMID:25848047

  15. Obesity and Breast Cancer: The Roles of Peroxisome Proliferator-Activated Receptor-γ and Plasminogen Activator Inhibitor-1

    PubMed Central

    Carter, Jennifer C.; Church, Frank C.

    2009-01-01

    Breast cancer is the most prominent cancer among females in the United States. There are a number of risk factors associated with development of breast cancer, including consumption of a high-fat diet and obesity. Plasminogen activator inhibitor-1 (PAI-1) is a cytokine upregulated in obesity whose expression is correlated with a poor prognosis in breast cancer. As a key mediator of adipogenesis and regulator of adipokine production, peroxisome proliferator-activated receptor-γ (PPAR-γ) is involved in PAI-1 expression from adipose tissue. We summarize the current knowledge linking PPAR-γ and PAI-1 expression to high-fat diet and obesity in the risk of breast cancer. PMID:19672469

  16. Gene expression for peroxisome-associated enzymes in hepatocellular carcinomas induced by ciprofibrate, a hypolipidemic compound

    SciTech Connect

    Rao, M.S.; Nemali, M.R.; Reddy, J.K.

    1986-03-05

    Administration of hypolipidemic compounds leads to marked proliferation of peroxisomes and peroxisome-associated enzymes (PAE) in the livers of rodents and non-rodent species. The increase peroxisome-associated enzymes such as fatty acid ..beta..-oxidation system and catalase is shown to be due to an increase in the levels of mRNA. In this experiment they have examined hepatocellular carcinomas (HCC), induced in male F-344 rats by ciprofibrate (0.025%, w/w for 60 weeks), for gene expression of PAE. Total RNA was purified from HCC as well as from control and ciprofibrate (0.025% for 2 weeks) fed rat livers. Northern blot analysis was performed using (32/sub p/)cDNA probes for albumin, fatty acetyl-CoA oxidase, enoyl-CoA hydratase 3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and catalase. mRNA levels in HCC for albumin, fatty acid ..beta..-oxidation enzymes and catalase were comparable with those levels observed in the livers of rats given ciprofibrate for 2 weeks. In control livers the mRNAs for ..beta..-oxidation enzymes were low. Albumin mRNA levels in all the 3 groups were comparable. Additional studies are necessary to determine whether the increased level of mRNAs for the ..beta..-oxidation enzymes in HCC is due to the effect of ciprofibrate or to the gene amplification.

  17. Phenylbutyrate Induces Apoptosis and Lipid Accumulations via a Peroxisome Proliferator-Activated Receptor Gamma-Dependent Pathway

    PubMed Central

    Milkevitch, Matthew; Beardsley, Nancy J.; Delikatny, E. James

    2013-01-01

    The effects of the selective peroxisome proliferator activated receptor-gamma (PPAR-?) inhibitor GW9662 on phenylbutyrate (PB)-induced NMR-detectable lipid metabolites was investigated on DU145 prostate cancer cells. DU145 cells were perfused with 10 mM PB in the presence or absence of 1 M of GW9662 and the results monitored by 31P and diffusion-weighted 1H NMR spectroscopy. GW9662 completely reversed PB-induced NMR-visible lipid and total choline accumulation in 1H spectra and glycerophosphocholine and ?-NTP in 31P spectra. In addition, pre-incubation with GW9662 significantly reduced PB-induced caspase-3 activation, reversed the G1 block as measured by flow cytometry, and otherwise had little effect on cell survival as measured by MTT assay. These results suggest that the NMR visible lipid accumulation and apoptosis induced by PB treatment occurs through a mechanism that is mediated by PPAR-?. PMID:20225233

  18. Peroxisome proliferator-activated receptor {alpha} agonist-induced down-regulation of hepatic glucocorticoid receptor expression in SD rats

    SciTech Connect

    Chen Xiang; Li Ming; Sun Weiping; Bi Yan; Cai Mengyin; Liang Hua; Yu Qiuqiong; He Xiaoying; Weng Jianping

    2008-04-18

    It was reported that glucocorticoid production was inhibited by fenofibrate through suppression of type-1 11{beta}-hydroxysteroid dehydrogenase gene expression in liver. The inhibition might be a negative-feedback regulation of glucocorticoid receptor (GR) activity by peroxisome proliferator-activated receptor alpha (PPAR{alpha}), which is quickly induced by glucocorticoid in the liver. However, it is not clear if GR expression is changed by fenofibrate-induced PPAR{alpha} activation. In this study, we tested this possibility in the liver of Sprague-Dawley rats. GR expression was reduced by fenofibrate in a time- and does-dependent manner. The inhibition was observed in liver, but not in fat and muscle. The corticosterone level in the blood was increased significantly by fenofibrate. These effects of fenofibrate were abolished by PPAR{alpha} inhibitor MK886, suggesting that fenofibrate activated through PPAR{alpha}. In conclusion, inhibition of GR expression may represent a new molecular mechanism for the negative feedback regulation of GR activity by PPAR{alpha}.

  19. Protective Role for Tissue Inhibitor of Metalloproteinase-4, a Novel Peroxisome Proliferator-Activated Receptor-? Target Gene, in Smooth Muscle in Deoxycorticosterone Acetate-Salt Hypertension.

    PubMed

    Ketsawatsomkron, Pimonrat; Keen, Henry L; Davis, Deborah R; Lu, Ko-Ting; Stump, Madeliene; De Silva, T Michael; Hilzendeger, Aline M; Grobe, Justin L; Faraci, Frank M; Sigmund, Curt D

    2016-01-01

    Loss of peroxisome proliferator-activated receptor-? (PPAR?) function causes hypertension, whereas its activation lowers blood pressure. Evidence suggests that these effects may be attributable to PPAR? activity in the vasculature. However, the specific transcriptional targets of PPAR? in vessels remain largely unidentified. In this study, we examined the role of smooth muscle PPAR? during salt-sensitive hypertension and investigated its transcriptional targets and functional effect. Transgenic mice expressing dominant-negative PPAR? (S-P467L) in smooth muscle cells were more prone to deoxycorticosterone acetate-salt-induced hypertension and mesenteric arterial dysfunction compared with nontransgenic controls. Despite similar morphometry at baseline, vascular remodeling in conduit and small arteries was enhanced in S-P467L after deoxycorticosterone acetate-salt treatment. Gene expression profiling in aorta and mesenteric arteries revealed significantly decreased expression of tissue inhibitor of metalloproteinase-4 (TIMP-4) in S-P467L. Expression of TIMP-4 was increased by deoxycorticosterone acetate-salt treatment, but this increase was ablated in S-P467L. Interference with PPAR? activity either by treatment with a PPAR? inhibitor, GW9662, or by expressing P467L PPAR? markedly suppressed TIMP-4 in primary smooth muscle cells. PPAR? binds to a PPAR response element (PPRE) in chromatin close to the TIMP-4 gene in smooth muscle cells, suggesting that TIMP-4 is a novel target of PPAR?. The interference with PPAR? and decrease in TIMP-4 were accompanied by an increase in total matrix metalloproteinase activity. PPAR?-mediated loss of TIMP-4 increased, whereas overexpression of TIMP-4 decreased smooth muscle cell migration in a scratch assay. Our findings highlight a protective mechanism induced by PPAR? in deoxycorticosterone acetate-salt treatment, establishing a novel mechanistic link between PPAR? and TIMP-4. PMID:26597823

  20. Histone deacetylase inhibitor upregulates peroxisomal fatty acid oxidation and inhibits apoptotic cell death in abcd1-deficient glial cells.

    PubMed

    Singh, Jaspreet; Khan, Mushfiquddin; Pujol, Aurora; Baarine, Mauhamad; Singh, Inderjit

    2013-01-01

    In X-ALD, mutation/deletion of ALD gene (ABCD1) and the resultant very long chain fatty acid (VLCFA) derangement has dramatically opposing effects in astrocytes and oligodendrocytes. While loss of Abcd1 in astrocytes produces a robust inflammatory response, the oligodendrocytes undergo cell death leading to demyelination in X-linked adrenoleukodystrophy (X-ALD). The mechanisms of these distinct pathways in the two cell types are not well understood. Here, we investigated the effects of Abcd1-knockdown and the subsequent alteration in VLCFA metabolism in human U87 astrocytes and rat B12 oligodendrocytes. Loss of Abcd1 inhibited peroxisomal β-oxidation activity and increased expression of VLCFA synthesizing enzymes, elongase of very long chain fatty acids (ELOVLs) (1 and 3) in both cell types. However, higher induction of ELOVL's in Abcd1-deficient B12 oligodendrocytes than astrocytes suggests that ELOVL pathway may play a prominent role in oligodendrocytes in X-ALD. While astrocytes are able to maintain the cellular homeostasis of anti-apoptotic proteins, Abcd1-deletion in B12 oligodendrocytes downregulated the anti-apototic (Bcl-2 and Bcl-xL) and cell survival (phospho-Erk1/2) proteins, and upregulated the pro-apoptotic proteins (Bad, Bim, Bax and Bid) leading to cell loss. These observations provide insights into different cellular signaling mechanisms in response to Abcd1-deletion in two different cell types of CNS. The apoptotic responses were accompanied by activation of caspase-3 and caspase-9 suggesting the involvement of mitochondrial-caspase-9-dependent mechanism in Abcd1-deficient oligodendrocytes. Treatment with histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) corrected the VLCFA derangement both in vitro and in vivo, and inhibited the oligodendrocytes loss. These observations provide a proof-of principle that HDAC inhibitor SAHA may have a therapeutic potential for X-ALD. PMID:23923017

  1. Clofibrate treatment in pigs: Effects on parameters critical with respect to peroxisome proliferator-induced hepatocarcinogenesis in rodents

    PubMed Central

    Luci, Sebastian; Giemsa, Beatrice; Hause, Gerd; Kluge, Holger; Eder, Klaus

    2007-01-01

    Background In rodents treatment with fibrates causes hepatocarcinogenesis, probably as a result of oxidative stress and an impaired balance between apoptosis and cell proliferation in the liver. There is some debate whether fibrates could also induce liver cancer in species not responsive to peroxisome proliferation. In this study the effect of clofibrate treatment on peroxisome proliferation, production of oxidative stress, gene expression of pro- and anti-apoptotic genes and proto-oncogenes was investigated in the liver of pigs, a non-proliferating species. Results Pigs treated with clofibrate had heavier livers (+16%), higher peroxisome counts (+61%), higher mRNA concentration of acyl-CoA oxidase (+66%), a higher activity of catalase (+41%) but lower concentrations of hydrogen peroxide (-32%) in the liver than control pigs (P < 0.05); concentrations of lipid peroxidation products (thiobarbituric acid-reactive substances, conjugated dienes) and total and reduced glutathione in the liver did not differ between both groups. Clofibrate treated pigs also had higher hepatic mRNA concentrations of bax and the proto-oncogenes c-myc and c-jun and a lower mRNA concentration of bcl-XL than control pigs (P < 0.05). Conclusion The data of this study show that clofibrate treatment induces moderate peroxisome proliferation but does not cause oxidative stress in the liver of pigs. Gene expression analysis indicates that clofibrate treatment did not inhibit but rather stimulated apoptosis in the liver of these animals. It is also shown that clofibrate increases the expression of the proto-oncogenes c-myc and c-jun in the liver, an event which could be critical with respect to carcinogenesis. As the extent of peroxisome proliferation by clofibrate was similar to that observed in humans, the pig can be regarded as a useful model for investigating the effects of peroxisome proliferators on liver function and hepatocarcinogenesis. PMID:17437637

  2. Fenofibrate, a peroxisome proliferator-activated receptor α ligand, prevents abnormal liver function induced by a fasting–refeeding process

    SciTech Connect

    Lee, Joon No; Dutta, Raghbendra Kumar; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu; Yoo, Kyeong-Won; Immune-network Pioneer Research Center, Department of Biochemistry, College of Medicine, Dong-A University, Busan ; Song, Seung Ryel; Park, Do-Sim; Department of Laboratory of Medicine, School of Medicine, Wonkwang University, Iksan ; So, Hong-Seob; Park, Raekil

    2013-12-06

    Highlights: •A fasting–refeeding high fat diet (HDF) model mimics irregular eating habit. •A fasting–refeeding HFD induces liver ballooning injury. •A fasting–refeeding HDF process elicits hepatic triglyceride accumulation. •Fenofibrate, PPARα ligand, prevents liver damage induced by refeeding HFD. -- Abstract: Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is an anti-hyperlipidemic agent that has been widely used in the treatment of dyslipidemia. In this study, we examined the effect of fenofibrate on liver damage caused by refeeding a high-fat diet (HFD) in mice after 24 h fasting. Here, we showed that refeeding HFD after fasting causes liver damage in mice determined by liver morphology and liver cell death. A detailed analysis revealed that hepatic lipid droplet formation is enhanced and triglyceride levels in liver are increased by refeeding HFD after starvation for 24 h. Also, NF-κB is activated and consequently induces the expression of TNF-α, IL1-β, COX-2, and NOS2. However, treating with fenofibrate attenuates the liver damage and triglyceride accumulation caused by the fasting–refeeding HFD process. Fenofibrate reduces the expression of NF-κB target genes but induces genes for peroxisomal fatty acid oxidation, peroxisome biogenesis and mitochondrial fatty acid oxidation. These results strongly suggest that the treatment of fenofibrate ameliorates the liver damage induced by fasting–refeeding HFD, possibly through the activation of fatty acid oxidation.

  3. Activation of peroxisome proliferator-activated receptor ? ameliorates monocrotaline-induced pulmonary arterial hypertension in rats

    PubMed Central

    XIE, XINMING; WANG, GUIZUO; ZHANG, DEXIN; ZHANG, YONGHONG; ZHU, YANTING; LI, FANGWEI; LI, SHAOJUN; LI, MANXIANG

    2015-01-01

    Activation of peroxisome proliferator-activated receptor ? (PPAR?) suppresses the proliferation of pulmonary artery smooth muscle cells (PASMCs) and vascular remodeling in rats and humans, and therefore improves the development of pulmonary arterial hypertension (PAH). However, molecular mechanisms underlying these effects have not been completely understood. In the present study, the effects of PPAR? activation in monocrotaline (MCT)-induced pulmonary artery remodeling in rats were investigated. Eighteen Sprague-Dawley (SD) rats were randomly assigned into three groups (n=6): Control (Con), PAH and PAH treated with rosiglitazone (MCT + Rosi). The right ventricular systolic pressure (RVSP), the ratio of the right to left ventricle plus septum weight [RV/(LV + S)], the percentage of medial wall thickness (%MT) and wall area (%WA) were used to evaluate the development of PAH. Tissue morphology was measured using hematoxylin and eosin staining. The protein levels of the phosphatase and tensin homologue deleted on chromosome ten (PTEN), Akt (ser473) phosphorylation (p-Akt) and total Akt in intrapulmonary arteries were determined by western blot analysis. MCT treatment significantly increased the RVSP, which was reduced by rosiglitazone treatment. The ratio of RV/(LV + S), %MT and %WA induced by MCT were similarly inhibited, which was associated with the increase of PTEN expression and the inhibition of Akt phosphorylation levels by rosiglitazone. In conclusion, activation of PPAR? ameliorates the proliferation of PASMCs and vascular remodeling by regulating the PTEN/PI3K/Akt pathway, suggesting that the activation of PPAR? has potential benefits for PAH. PMID:26171162

  4. Ginsenoside Rb? induces type I collagen expression through peroxisome proliferator-activated receptor-delta.

    PubMed

    Kwok, Hoi-Hin; Yue, Patrick Ying-Kit; Mak, Nai-Ki; Wong, Ricky Ngok-Shun

    2012-08-15

    Wrinkle formation is one of the primary characteristics of skin aging, the major cause of wrinkle is the loss of structural protein type I collagen in dermal layer of skin. Topical application of natural substances to reduce wrinkle is gaining attention in recent years. Although a number of polyphenoic compounds are suggested to prevent ultraviolet-induced wrinkle, very few of them are able to increase type I collagen synthesis directly. Ginseng has been known in folk medicine of its beneficial effect to skin. The present study investigate the effect of ginsenoside on type I collagen induction in human dermal fibroblasts. Ginsenoside Rb? was shown to induce type I collagen expression in dermal fibroblasts in a dose- and time-dependent manner. Recent studies suggest the important post-transcriptional regulatory role of microRNAs; here we demonstrated that miR-25 can directly inhibit type I collagen protein expression, and treatment of fibroblasts with Rb? can reduce the inhibition by decreasing miR-25 level. Furthermore, we identified that the nuclear receptor, peroxisome proliferator-activated receptor-delta (PPAR?) is the key mediator of Rb?-induced type I collagen expression. Knockdown of PPAR? by small-interference RNA abolished the Rb?-induced type I collagen production and reversed the Rb?-suppressed miR-25 expression. These results demonstrated that ginsenoside Rb? can increase target gene expression through transcriptional pathway, at the same time, inhibit the corresponding miRNA expression to minimize the translation repression. Furthermore, this study provide solid support of ginsenoside Rb?-induced type I collagen expression, which warrant further study in the dermatological application of ginsenosides in skin disorders. PMID:22692056

  5. Peroxisomal disorders.

    PubMed

    Aubourg, Patrick; Wanders, Ronald

    2013-01-01

    The peroxisomal disorders represent a group of genetic diseases in man in which there is an impairment in one or more peroxisomal functions. The peroxisomal disorders are subdivided into three subgroups comprising: (1) the peroxisome biogenesis disorders (PBDs); (2) the single peroxisomal (enzyme-) protein deficiencies; and (3) the single peroxisomal substrate transport deficiencies. The PBD group comprises four different disorders that include Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD), infantile Refsum disease (IRD), and rhizomelic chondrodysplasia punctata (RCDP). ZS, NALD, and IRD are clearly distinct from RCDP and are usually referred to as the Zellweger spectrum with ZS being the most severe, and IRD the less severe disorder, with sometimes onset in adulthood. The single peroxisomal enzyme deficiency group comprises seven different disorders, of which D-bifunctional protein and phytanoyl-CoA hydroxylase (adult Refsum disease) deficiencies are the most frequent. The single peroxisomal substrate transport deficiency group consists of only one disease, X-linked adrenoleukodystrophy. It is the purpose of this chapter to describe the current state of knowledge about the clinical, biochemical, cellular, and molecular aspects of peroxisomal diseases, and to provide guidelines for their post- and prenatal diagnosis. Therapeutic interventions are mostly limited to X-linked adrenoleukodystrophy. PMID:23622381

  6. Identification of transcriptional networks involved in peroxisome proliferator chemical-induced hepatocyte proliferation

    EPA Science Inventory

    Peroxisome proliferator chemical (PPC) exposure leads to increases in rodent liver tumors through a non-genotoxic mode of action (MOA). The PPC MOA includes increased oxidative stress, hepatocyte proliferation and decreased apoptosis. We investigated the putative genetic regulato...

  7. Differential Roles of Smad1 and p38 Kinase in Regulation of Peroxisome Proliferator-activating Receptor ? during Bone Morphogenetic Protein 2-induced Adipogenesis

    PubMed Central

    Hata, Kenji; Nishimura, Riko; Ikeda, Fumiyo; Yamashita, Kenji; Matsubara, Takuma; Nokubi, Takashi; Yoneda, Toshiyuki

    2003-01-01

    Bone morphogenetic protein 2 (BMP2) promotes the differentiation of undifferentiated mesenchymal cells into adipocytes. To investigate the molecular mechanisms that regulate this differentiation process, we studied the relationship between BMP2 signaling and peroxisome proliferator-activating receptor ? (PPAR?) during adipogenesis of mesenchymal cells by using pluripotent mesenchymal cell line C3H10T1/2. In C3H10T1/2 cells, BMP2 induced expression of PPAR? along with adipogenesis. Overexpression of Smad6, a natural antagonist for Smad1, blocked PPAR? expression and adipocytic differentiation induced by BMP2. Overexpression of dominant-negative PPAR? also diminished adipocytic differentiation of C3H10T1/2 cells, suggesting the central role of PPAR? in BMP2-induced adipocytic differentiation. Specific inhibitors for p38 kinase inhibited BMP2-induced adipocytic differentiation and transcriptional activation of PPAR?, whereas overexpression of Smad6 had no effect on transcriptional activity of PPAR?. Furthermore, activation of p38 kinase by overexpression of TAK1 and TAB1, without affecting PPAR? expression, led the up-regulation of transcriptional activity of PPAR?. These results suggest that both Smad and p38 kinase signaling are concomitantly activated and responsible for BMP2-induced adipocytic differentiation by inducing and up-regulating PPAR?, respectively. Thus, BMP2 controls adipocytic differentiation by using two distinct signaling pathways that play differential roles in this process in C3H10T1/2 cells. PMID:12589053

  8. Peroxisome proliferator-activated receptor γ attenuates serotonin-induced pulmonary artery smooth muscle cell proliferation and apoptosis inhibition involving ERK1/2 pathway.

    PubMed

    Han, Xinyuan; Chen, Chunyan; Cheng, Gong; Liang, Lei; Yao, Xiaowei; Yang, Guang; You, Penghua; Shou, Xiling

    2015-07-01

    Serotonin (5-HT) has been shown to be involved in pulmonary vascular remodeling in pulmonary arterial hypertension (PAH) by inducing pulmonary artery smooth muscle cells (PASMCs) proliferation and inhibiting PASMC apoptosis. Peroxisome proliferator-activated receptor γ (PPARγ) plays a crucial role in regulating proliferation and apoptosis of many cell types. Moreover, recently, loss of PPARγ has also been reported to be associated with the development of PAH. The present study is aimed to assess whether PPARγ is involved in 5-HT induced PASMC proliferation and apoptosis inhibition and the possible mechanism. We found that 5-HT could induce PASMC proliferation and inhibit PASMC apoptosis in a dose-dependent manner. Furthermore, we found that 5-HT negatively regulated PPARγ expression and gene promoter activity in PASMCs and 5-HT induced PASMC proliferation and apoptosis resistance could be abolished by PPARγ agonists and enhanced by PPARγ inhibitor. In addition, we found that extracellular signal-regulated kinase (ERK) signaling pathway mediated the 5-HT-induced inhibition of PPARγ expression. Our results might provide novel insights into the mechanisms for the pro-remodeling action of 5-HT in pulmonary vasculature. PMID:25937083

  9. Metal-catalyzed oxidation induces carbonylation of peroxisomal proteins and loss of enzymatic activities.

    PubMed

    Nguyen, A T; Donaldson, R P

    2005-07-01

    Peroxisomes are involved in oxidative metabolic reactions and have the capacity to generate large amounts of reactive oxygen species that could damage biomolecules including their own resident proteins. The purpose of this study was to determine whether peroxisomal proteins are susceptible to oxidation and whether oxidative damage affects their enzymatic activity. Peroxisomal proteins were subjected to metal-catalyzed oxidation (MCO) with CuCl(2)/ascorbate and derivatized with 2,4-dinitrophenylhydrazine which allowed for spectrophotometric quantification of carbonylation. Immunochemical detection of carbonylated peroxisomal proteins, resolved by gel electrophoresis and detected with anti-DNP antibodies, revealed five oxidatively modified proteins with the following molecular weights: 80, 66, 62, 55, and 50 kDa. The proteins at 66, 62, and 55 kDa were identified as malate synthase (MS), isocitrate lyase, and catalase (CAT), respectively. MS and CAT were estimated to contain 2-3 mol of carbonyl/mol of protein as a result of MCO. Enzymatic assays revealed varying degrees of activity loss. Isocitrate lyase and malate synthase showed significant loss of activity while catalase and malate dehydrogenase were less inhibited by carbonylation. Our findings show that peroxisomal proteins are vulnerable to MCO damage and thus may also be affected by in vivo exposure to reactive oxygen species. PMID:15922287

  10. Bezafibrate induces a mitochondrial derangement in human cell lines: a PPAR-independent mechanism for a peroxisome proliferator.

    PubMed

    Scatena, R; Bottoni, P; Vincenzoni, F; Messana, I; Martorana, G E; Nocca, G; De Sole, P; Maggiano, N; Castagnola, M; Giardina, B

    2003-11-01

    Bezafibrate is a hypolipidemic drug that belongs to the group of peroxisome proliferators because it binds to peroxisome proliferator-activated receptors type alpha (PPARs). Peroxisome proliferators produce a myriad of extraperoxisomal effects, which are not necessarily dependent on their interaction with PPARs. An investigation on the peculiar activities of bezafibrate could clarify some of the molecular events and the relationship with the biochemical and pharmacological properties of this class of compounds. In this view, the human acute promyelocytic leukemia HL-60 cell line and human rabdomiosarcoma TE-671 cell line were cultured in media containing bezafibrate and a number of observations such as spectrophotometric analysis of mitochondrial respiratory chain enzymes, NMR metabolite determinations, phosphofructokinase enzymatic analysis, and differentiation assays were carried on. Bezafibrate induced a derangement of NADH cytochrome c reductase activity accompanied by metabolic alterations, mainly a shift to anaerobic glycolysis and an increase of fatty acid oxidation, as shown by NMR analysis of culture supernatants where acetate, lactate, and alanine levels increased. On the whole, the present results suggest a biochemical profile and a therapeutic role of this class of PPARs ligands more complex than those previously proposed. PMID:14615970

  11. Cucurbitane Triterpenoid from Momordica charantia Induces Apoptosis and Autophagy in Breast Cancer Cells, in Part, through Peroxisome Proliferator-Activated Receptor ? Activation.

    PubMed

    Weng, Jing-Ru; Bai, Li-Yuan; Chiu, Chang-Fang; Hu, Jing-Lan; Chiu, Shih-Jiuan; Wu, Chia-Yung

    2013-01-01

    Although the antitumor activity of the crude extract of wild bitter gourd (Momordica charantia L.) has been reported, its bioactive constituents and the underlying mechanism remain undefined. Here, we report that 3 ? ,7 ? -dihydroxy-25-methoxycucurbita-5,23-diene-19-al (DMC), a cucurbitane-type triterpene isolated from wild bitter gourd, induced apoptotic death in breast cancer cells through peroxisome proliferator-activated receptor (PPAR) ? activation. Luciferase reporter assays indicated the ability of DMC to activate PPAR ? , and pharmacological inhibition of PPAR ? protected cells from DMC's antiproliferative effect. Western blot analysis indicated that DMC suppressed the expression of many PPAR ? -targeted signaling effectors, including cyclin D1, CDK6, Bcl-2, XIAP, cyclooxygenase-2, NF- ? B, and estrogen receptor ? , and induced endoplasmic reticulum stress, as manifested by the induction of GADD153 and GRP78 expression. Moreover, DMC inhibited mTOR-p70S6K signaling through Akt downregulation and AMPK activation. The ability of DMC to activate AMPK in liver kinase (LK) B1-deficient MDA-MB-231 cells suggests that this activation was independent of LKB1-regulated cellular metabolic status. However, DMC induced a cytoprotective autophagy presumably through mTOR inhibition, which could be overcome by the cotreatment with the autophagy inhibitor chloroquine. Together, the ability of DMC to modulate multiple PPAR ? -targeted signaling pathways provides a mechanistic basis to account for the antitumor activity of wild bitter gourd. PMID:23843889

  12. The Ras Inhibitors Caveolin-1 and Docking Protein 1 Activate Peroxisome Proliferator-Activated Receptor ? through Spatial Relocalization at Helix 7 of Its Ligand-Binding Domain ?

    PubMed Central

    Burgermeister, Elke; Friedrich, Teresa; Hitkova, Ivana; Regel, Ivonne; Einwchter, Henrik; Zimmermann, Wolfgang; Rcken, Christoph; Perren, Aurel; Wright, Matthew B.; Schmid, Roland M.; Seger, Rony; Ebert, Matthias P. A.

    2011-01-01

    Peroxisome proliferator-activated receptor ? (PPAR?) is a transcription factor that promotes differentiation and cell survival in the stomach. PPAR? upregulates and interacts with caveolin-1 (Cav1), a scaffold protein of Ras/mitogen-activated protein kinases (MAPKs). The cytoplasmic-to-nuclear localization of PPAR? is altered in gastric cancer (GC) patients, suggesting a so-far-unknown role for Cav1 in spatial regulation of PPAR? signaling. We show here that loss of Cav1 accelerated proliferation of normal stomach and GC cells in vitro and in vivo. Downregulation of Cav1 increased Ras/MAPK-dependent phosphorylation of serine 84 in PPAR? and enhanced nuclear translocation and ligand-independent transcription of PPAR? target genes. In contrast, Cav1 overexpression sequestered PPAR? in the cytosol through interaction of the Cav1 scaffolding domain (CSD) with a conserved hydrophobic motif in helix 7 of PPAR?'s ligand-binding domain. Cav1 cooperated with the endogenous Ras/MAPK inhibitor docking protein 1 (Dok1) to promote the ligand-dependent transcriptional activity of PPAR? and to inhibit cell proliferation. Ligand-activated PPAR? also reduced tumor growth and upregulated the Ras/MAPK inhibitors Cav1 and Dok1 in a murine model of GC. These results suggest a novel mechanism of PPAR? regulation by which Ras/MAPK inhibitors act as scaffold proteins that sequester and sensitize PPAR? to ligands, limiting proliferation of gastric epithelial cells. PMID:21690289

  13. Identification of a peroxisome proliferator responsive element (PPRE)-like cis-element in mouse plasminogen activator inhibitor-1 gene promoter

    SciTech Connect

    Chen Jiegen; Li Xi; Huang Haiyan; Liu Honglei; Liu Deguo; Song Tanjing; Ma Chungu; Ma Duan; Song Houyan; Tang Qiqun . E-mail: qqtang@shmu.edu.cn

    2006-09-01

    PAI-1 is expressed and secreted by adipose tissue which may mediate the pathogenesis of obesity-associated cardiovascular complications. Evidence is presented in this report that PAI-1 is not expressed by preadipocyte, but significantly induced during 3T3-L1 adipocyte differentiation and the PAI-1 expression correlates with the induction of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}). A peroxisome proliferator responsive element (PPRE)-like cis-element (-206TCCCCCATGCCCT-194) is identified in the mouse PAI-1 gene promoter by electrophoretic mobility shift assay (EMSA) combined with transient transfection experiments; the PPRE-like cis-element forms a specific DNA-protein complex only with adipocyte nuclear extracts, not with preadipocyte nuclear extracts; the DNA-protein complex can be totally competed away by non-labeled consensus PPRE, and can be supershifted with PPAR{gamma} antibody. Mutation of this PPRE-like cis-element can abolish the transactivation of mouse PAI-1 promoter mediated by PPAR{gamma}. Specific PPAR{gamma} ligand Pioglitazone can significantly induce the PAI-1 expression, and stimulate the secretion of PAI-1 into medium.

  14. Collecting duct-specific deletion of peroxisome proliferator-activated receptor gamma blocks thiazolidinedione-induced fluid retention.

    PubMed

    Zhang, Hui; Zhang, Aihua; Kohan, Donald E; Nelson, Raoul D; Gonzalez, Frank J; Yang, Tianxin

    2005-06-28

    The peroxisome proliferator-activated receptor subtype gamma (PPARgamma) ligands, namely the synthetic insulin-sensitizing thiazolidinedione (TZD) compounds, have demonstrated great potential in the treatment of type II diabetes. However, their clinical applicability is limited by a common and serious side effect of edema. To address the mechanism of TZD-induced edema, we generated mice with collecting duct (CD)-specific disruption of the PPARgamma gene. We found that mice with CD knockout of this receptor were resistant to the rosiglitazone- (RGZ) induced increases in body weight and plasma volume expansion found in control mice expressing PPARgamma in the CD. RGZ reduced urinary sodium excretion in control and not in conditional knockout mice. Furthermore, RGZ stimulated sodium transport in primary cultures of CD cells expressing PPARgamma and not in cells lacking this receptor. These findings demonstrate a PPARgamma-dependent pathway in regulation of sodium transport in the CD that underlies TZD-induced fluid retention. PMID:15956187

  15. Overexpression of peroxisomal testis-specific 1 protein induces germ cell apoptosis and leads to infertility in male mice

    PubMed Central

    Kaczmarek, Karina; Studencka, Maja; Meinhardt, Andreas; Wieczerzak, Krzysztof; Thoms, Sven; Engel, Wolfgang; Grzmil, Pawel

    2011-01-01

    ?Peroxisomal testis-specific 1 gene (Pxt1) is the only male germ cellspecific gene that encodes a peroxisomal protein known to date. To elucidate the role of Pxt1 in spermatogenesis, we generated transgenic mice expressing a c-MYC-PXT1 fusion protein under the control of the PGK2 promoter. Overexpression of Pxt1 resulted in induction of male germ cells apoptosis mainly in primary spermatocytes, finally leading to male infertility. This prompted us to analyze the proapoptotic character of mouse PXT1, which harbors a BH3-like domain in the N-terminal part. In different cell lines, the overexpression of PXT1 also resulted in a dramatic increase of apoptosis, whereas the deletion of the BH3-like domain significantly reduced cell death events, thereby confirming that the domain is functional and essential for the proapoptotic activity of PXT1. Moreover, we demonstrated that PXT1 interacts with apoptosis regulator BAT3, which, if overexpressed, can protect cells from the PXT1-induced apoptosis. The PXT1-BAT3 association leads to PXT1 relocation from the cytoplasm to the nucleus. In summary, we demonstrated that PXT1 induces apoptosis via the BH3-like domain and that this process is inhibited by BAT3. PMID:21460186

  16. Agranulocytosis induced by proton pump inhibitors.

    PubMed

    Dury, Sandra; Nardi, Julie; Gozalo, Claire; Lebargy, Franois; Deslee, Gatan

    2012-01-01

    We report the first published case of agranulocytosis induced by omeprazole and its recurrence with esomeprazole, the S-isomer form of omeprazole. Interestingly, we found an homozygotous mutation of CYP2C19*17, responsible for the metabolism of proton pump inhibitors. PMID:22240865

  17. The role of peroxisome proliferator-activated receptor-{beta}/{delta} in epidermal growth factor-induced HaCaT cell proliferation

    SciTech Connect

    Liang Pengfei; Jiang Bimei; Yang Xinghua; Xiao Xianzhong Huang Xu; Long Jianhong; Zhang Pihong; Zhang Minghua; Xiao Muzhang; Xie Tinghong; Huang Xiaoyuan

    2008-10-15

    Epidermal growth factor (EGF) has been shown to be a potent mitogen for epidermal cells both in vitro and in vivo, thus contributing to the development of an organism. It has recently become clear that peroxisome proliferator-activated receptor-{beta}/{delta} (PPAR{beta}/{delta}) expression and activation is involved in the cell proliferation. However, little is known about the role of PPAR{beta}/{delta} in EGF-induced proliferation of HaCaT keratinocytes. In this study, HaCaT cells were cultured in the presence and absence of EGF and we identified that EGF induced an increase of PPAR{beta}/{delta} mRNA and protein level expression in time-dependent and dose-dependent manner, and AG1487, an EGF receptor (EGFR) special inhibitor, caused attenuation of PPAR{beta}/{delta} protein expression. Electrophoretic mobility shift assay (EMSA) revealed that EGF significantly increased PPAR{beta}/{delta} binding activity in HaCaT keratinocytes. Antisense phosphorothioate oligonucleotides (asODNs) against PPAR{beta}/{delta} caused selectively inhibition of PPAR{beta}/{delta} protein content induced by EGF and significantly attenuated EGF-mediated cell proliferation. Treatment of the cells with L165041, a specific synthetic ligand for PPAR{beta}/{delta}, significantly enhanced EGF-mediated cell proliferation. Finally, c-Jun ablation inhibited PPAR{beta}/{delta} up-regulation induced by EGF, and chromatin immunoprecipitation (ChIP) showed that c-Jun bound to the PPAR{beta}/{delta} promoter and the binding increased in EGF-stimulated cells. These results demonstrate that EGF induces PPAR{beta}/{delta} expression in a c-Jun-dependent manner and PPAR{beta}/{delta} plays a vital role in EGF-stimulated proliferation of HaCaT cells.

  18. Anti-kindling Effect of Bezafibrate, a Peroxisome Proliferator-activated Receptors Alpha Agonist, in Pentylenetetrazole Induced Kindling Seizure Model

    PubMed Central

    Saha, Lekha; Bhandari, Swati; Bhatia, Alka; Banerjee, Dibyajyoti; Chakrabarti, Amitava

    2014-01-01

    Background and Purpose: Studies in the animals suggested that Peroxisome proliferators activated receptors (PPARs) may be involved in seizure control and selective agonists of PPAR ? or PPAR ? raise seizure thresholds. The present study was contemplated with the aim of evaluating the anti kindling effects and the mechanism of bezafibrate, a Peroxisome proliferator-activated receptors ? (PPAR-?) agonist in pentylenetetrazole (PTZ) induced kindling model of seizures in rats. Methods: In a PTZ kindled Wistar rat model, different doses of bezafibrate (100 mg/kg, 200 mg/kg and 300 mg/kg) were administered intraperitoneally 30 minutes before the PTZ injection. The PTZ injection was given on alternate day till the animal became fully kindled or till 10 weeks. The parameters measured were the latency to develop kindling and incidence of kindling, histopathological study of hippocampus, hippocampal lipid peroxidation studies, serum neuron specific enolase, and hippocampal DNA fragmentation study. Results: In this study, bezafibrate significantly reduced the incidence of kindling in PTZ treated rats and exhibited a marked prolongation in the latencies to seizures. In the present study bezafibrate decreased the thiobarbituric acid-reactive substance i.e. Malondialdehyde levels, increased the reduced glutathione levels, catalase and superoxide dismutase activity in the brain. This added to its additional neuroprotective effects. Bezafibrate also reduced the neuronal damage and apoptosis in hippocampal area of the brain. Therefore bezafibrate exerted anticonvulsant properties in PTZ induced kindling model in rats. Conclusions: These findings may provide insights into the understanding of the mechanism of bezafibrate as an anti kindling agent and could offer a useful support to the basic antiepileptic therapy in preventing the development of PTZ induced seizures, suggesting its potential for therapeutic applications in temporal lobe epilepsy. PMID:25625088

  19. Perfluorooctanoic acid induces peroxisomal fatty acid oxidation and cytokine expression in the liver of male Japanese medaka (Oryzias latipes).

    PubMed

    Yang, Jae-Ho

    2010-09-01

    Widespread contamination of perfluorooctanoic acid (PFOA) in the marine environment draws a great concern over its ecotoxicological impact on marine mammals and wildlife. In the present study, male Japanese medaka (Oryzias latipes) was adapted to seawater to mimic the marine environment and was then exposed to the nominal concentrations of 10, 50, 100 mg L(-1) PFOA for 7d. There were no impact on survival, relative liver and gonad size, and condition factor (measure of growth) at any concentration tested. Peroxisomal acyl-CoA oxidase (ACO) activity was elevated at the highest dose with a marginal significance (P=0.06). The increase of ACO activity was paralleled by the significant upregulation of PPAR-α expression at the same dose. PFOA induced a significant inhibition of catalase (CAT) activity at high doses with no changes of superoxide dismutase (SOD) or glutathione peroxidase (GPx) activities in the liver. These results strongly suggest that PFOA may induce peroxisomal fatty acid oxidation and impose the oxidative stress through the alteration of cellular oxidative homeostasis in the liver. PFOA increased the mRNA levels of proinflammatory cytokines such as IL-6, TNF-α and IL-1β, suggesting that it may be involved in inflammation and tissue injury. This study may contribute to understanding the mechanism of PFOA-induced hepatic toxicity in Japanese medaka and assessing the potential risk of PFOA in marine fish and wildlife. In addition, the present results obtained at the high concentrations may provide important biological endpoints relevant to situations such as environmental spills. PMID:20594573

  20. Modulation of VEGF-Induced Retinal Vascular Permeability by Peroxisome Proliferator-Activated Receptor-β/δ

    PubMed Central

    Suarez, Sandra; McCollum, Gary W.; Bretz, Colin A.; Yang, Rong; Capozzi, Megan E.; Penn, John S.

    2014-01-01

    Purpose. Vascular endothelial growth factor (VEGF)-induced retinal vascular permeability contributes to diabetic macular edema (DME), a serious vision-threatening condition. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) antagonist/reverse agonist, GSK0660, inhibits VEGF-induced human retinal microvascular endothelial cell (HRMEC) proliferation, tubulogenesis, and oxygen-induced retinal vasculopathy in newborn rats. These VEGF-induced HRMEC behaviors and VEGF-induced disruption of endothelial cell junctional complexes may well share molecular signaling events. Thus, we sought to examine the role of PPARβ/δ in VEGF-induced retinal hyperpermeability. Methods. Transendothelial electrical resistance (TEER) measurements were performed on HRMEC monolayers to assess permeability. Claudin-1/Claudin-5 localization in HRMEC monolayers was determined by immunocytochemistry. Extracellular signal-regulated protein kinases 1 and 2 (Erk 1/2) phosphorylation, VEGF receptor 1 (VEGFR1) and R2 were assayed by Western blot analysis. Expression of VEGFR1 and R2 was measured by quantitative RT-PCR. Last, retinal vascular permeability was assayed in vivo by Evans blue extravasation. Results. Human retinal microvascular endothelial cell monolayers treated with VEGF for 24 hours showed decreased TEER values that were completely reversed by the highest concentration of GSK0660 (10 μM) and PPARβ/δ-directed siRNA (20 μM). In HRMEC treated with VEGF, GSK0660 stabilized tight-junctions as evidenced by Claudin-1 staining, reduced phosphorylation of Erk1/2, and reduced VEGFR1/2 expression. Peroxisome proliferator-activated receptor β/δ siRNA had a similar effect on VEGFR expression and Claudin-1, supporting the specificity of GSK0660 in our experiments. Last, GSK0660 significantly inhibited VEGF-induced retinal vascular permeability and reduced retinal VEGFR1and R2 levels in C57BL/6 mice. Conclusions. These data suggest a protective effect for PPARβ/δ antagonism against VEGF-induced vascular permeability, possibly through reduced VEGFR expression. Therefore, antagonism/reverse agonism of PPARβ/δ siRNA may represent a novel therapeutic methodology against retinal hyperpermeability and is worthy of future investigation. PMID:25406289

  1. Impacts of peroxisome proliferator-activated receptor-? activation on cigarette smoke-induced exacerbated response to bacteria.

    PubMed

    Morissette, Mathieu C; Shen, Pamela; Thayaparan, Danya; Stmpfli, Martin R

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is characterised by a state of chronic pulmonary inflammation punctuated by microbial exacerbations. Despite advances in treatment options, COPD remains difficult to manage. In this study, we investigated the potential of peroxisome proliferator-activated receptor (PPAR)? activation as a new therapy against cigarette smoke-induced inflammation and its associated bacterial exacerbation. C57BL/6 mice were exposed to room air or cigarette smoke for either 4 days or 4 weeks and treated either prophylactically or therapeutically with rosiglitazone. The impact of rosiglitazone on cigarette smoke-induced exacerbated response to the bacterial pathogen nontypeable Haemophilus influenzae (NTHi) was studied using the therapeutic treatment protocol. We found that rosiglitazone was able to reduce cigarette smoke-induced neutrophilia both when administered prophylactically or therapeutically. Therapeutic intervention with rosiglitazone was also effective in preventing cigarette smoke-induced neutrophilia exacerbation following NTHi infection. Moreover, the anti-inflammatory effects of rosiglitazone did not lead to an increase in the pulmonary bacterial burden, unlike dexamethasone. Altogether, our data suggest that pharmacological activation of PPAR? may be an effective therapeutic approach to improve COPD management, as it is able to reduce cigarette smoke-induced inflammation and decrease the magnitude of bacterial exacerbations, without compromising the ability of the immune system to control the infection. PMID:25034559

  2. Activation of peroxisome proliferator-activated receptor-? coactivator 1? ameliorates mitochondrial dysfunction and protects podocytes from aldosterone-induced injury.

    PubMed

    Yuan, Yanggang; Huang, Songming; Wang, Wenyan; Wang, Yingying; Zhang, Ping; Zhu, Chunhua; Ding, Guixia; Liu, Bicheng; Yang, Tianxin; Zhang, Aihua

    2012-10-01

    Glomerular podocytes are highly specialized epithelial cells whose injury in glomerular diseases causes proteinuria. Since mitochondrial dysfunction is an early event in podocyte injury, we tested whether a major regulator of oxidative metabolism and mitochondrial function, the transcriptional coactivator peroxisome proliferator-activated receptor-? coactivator 1? (PGC-1?), affects podocyte damage. Aldosterone-induced injury decreased PGC-1? expression, and induced mitochondrial and podocyte damage in dose- and time-dependent manners. The suppression of endogenous PGC-1? by RNAi caused podocyte mitochondrial damage and apoptosis while its increase by infection with an adenoviral vector prevented aldosterone-induced mitochondrial malfunction and inhibited injury. Overexpression of the silent mating type information regulation 2 homolog 1, a gene upstream of PGC-1?, prevented aldosterone-induced mitochondrial damage and podocyte injury by upregulating PGC-1? at both the transcriptional and post-translational levels. Resveratrol, a SIRT1 activator, attenuated aldosterone-induced mitochondrial malfunction and podocyte injury in vitro and in aldosterone-infused mice in vivo. Hence, endogenous PGC-1? may be important for maintenance of mitochondrial function in podocytes under normal conditions. Activators of SIRT1, such as resveratol, may be therapeutically useful in glomerular diseases to promote and maintain PGC-1? expression and, consequently, podocyte integrity. PMID:22648295

  3. Hepatic sirtuin 1 is dispensable for fibrate-induced peroxisome proliferator-activated receptor-? function in vivo.

    PubMed

    Bonzo, Jessica A; Brocker, Chad; Jiang, Changtao; Wang, Rui-Hong; Deng, Chu-Xia; Gonzalez, Frank J

    2014-04-01

    Peroxisome proliferator-activated receptor-? (PPAR?) mediates metabolic remodeling, resulting in enhanced mitochondrial and peroxisomal ?-oxidation of fatty acids. In addition to the physiological stimuli of fasting and high-fat diet, PPAR? is activated by the fibrate class of drugs for the treatment of dyslipidemia. Sirtuin 1 (SIRT1), an important regulator of energy homeostasis, was downregulated in fibrate-treated wild-type mice, suggesting PPAR? regulation of Sirt1 gene expression. The impact of SIRT1 loss on PPAR? functionality in vivo was assessed in hepatocyte-specific knockout mice that lack the deacetylase domain of SIRT1 (Sirt1(?Liv)). Knockout mice were treated with fibrates or fasted for 24 h to activate PPAR?. Basal expression of the PPAR? target genes Cyp4a10 and Cyp4a14 was reduced in Sirt1(?Liv) mice compared with wild-type mice. However, no difference was observed between wild-type and Sirt1(?Liv) mice in either fasting- or fibrate-mediated induction of PPAR? target genes. Similar to the initial results, there was no difference in fibrate-activated PPAR? gene induction. To assess the relationship between SIRT1 and PPAR? in a pathophysiological setting, Sirt1(?Liv) mice were maintained on a high-fat diet for 14 wk, followed by fibrate treatment. Sirt1(?Liv) mice exhibited increased body mass compared with control mice. In the context of a high-fat diet, Sirt1(?Liv) mice did not respond to the cholesterol-lowering effects of the fibrate treatment. However, there were no significant differences in PPAR? target gene expression. These results suggest that, in vivo, SIRT1 deacetylase activity does not significantly impact induced PPAR? activity. PMID:24496310

  4. The peroxisome proliferator-activated receptor-? agonist pioglitazone protects against cisplatin-induced renal damage in mice.

    PubMed

    Jesse, Cristiano R; Bortolatto, Cristiani F; Wilhelm, Ethel A; Roman, Silvane Souza; Prigol, Marina; Nogueira, Cristina W

    2014-01-01

    Peroxisome proliferator-activated receptor-? (PPAR-?) agonists not only improve metabolic abnormalities of diabetes and consequent diabetic nephropathy, but they also protect against non-diabetic kidney disease in experimental models. Here, we investigated the effect of PPAR-? agonist pioglitazone against acute renal injury on a cisplatin model in mice. Nephrotoxicity was induced by a single intraperitoneal (i.p.) injection of cisplatin (10?mg?kg(-1)). Pioglitazone was administered for six consecutive days in doses of 15 or 30?mg?kg(-1) ?day(-1), per os (p.o.), starting 3?days before cisplatin injection. Cisplatin treatment to mice induced a marked renal failure, characterized by a significant increase in serum urea and creatinine levels and alterations in renal tissue architecture. Cisplatin exposure induced oxidative stress as indicated by decreased levels of non-enzymatic antioxidant defenses [glutathione (GSH) and ascorbic acid levels] and components of the enzymatic antioxidant defenses [superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx), glutathione reductase (GR) and and glutathione S-transferase(GST) activities)] in renal tissue. Administration of pioglitazone markedly protected against the increase in urea and creatinine levels and histological alterations in kidney induced by cisplatin treatment. Pioglitazone administration ameliorated GSH and ascorbic acid levels decreased by cisplatin exposure in mice. Pioglitazone protected against the inhibition of CAT, SOD, GPx, GR and GST activities induced by cisplatin in the kidneys of mice. These results indicated that pioglitazone has a protective effect against cisplatin-induced renal damage in mice. The protection is mediated by preventing the decline of antioxidant status. The results have implications in use of PPAR-? agonists in human application for protecting against drugs-induced nephrotoxicity. PMID:22987311

  5. 4-Hydroxydocosahexaenoic acid, a potent peroxisome proliferator-activated receptor {gamma} agonist alleviates the symptoms of DSS-induced colitis

    SciTech Connect

    Yamamoto, Keiko; Ninomiya, Yuichi; Iseki, Mioko; Nakachi, Yutaka; Kanesaki-Yatsuka, Yukiko; Yamanoue, Yu; Itoh, Toshimasa; Nishii, Yasuho; Petrovsky, Nikolai; Okazaki, Yasushi

    2008-03-14

    (5E,7Z,10Z,13Z,16Z,19Z)-4-Hydroxy-5,7,10,13,16,19-docosahexaenoic acid (4-OHDHA) is a potential agonist of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) and antidiabetic agent as has been previously reported. As PPAR{gamma} agonists may also have anti-inflammatory functions, in this study, we investigated whether 4-OHDHA has an inhibitory effect on expression of inflammatory genes in vitro and whether 4-OHDHA could relieve the symptoms of dextran sodium sulfate (DSS)-induced colitis in a murine model of inflammatory bowel disease. 4-OHDHA inhibited production of nitric oxide and expression of a subset of inflammatory genes including inducible nitric oxide synthase (Nos2/iNOS) and interleukin 6 (Il6) by lipopolysaccharide (LPS)-activated macrophages. In addition, 4-OHDHA-treated mice when compared to control mice not receiving treatment recovered better from the weight loss caused by DSS-induced colitis. Changes in disease activity index (DAI) of 4-OHDHA-treated mice were also more favorable than for control mice and were comparable with mice treated with a typical anti-inflammatory-drug, 5-aminosalichylic acid (5-ASA). These results suggest that 4-OHDHA has potentially clinically useful anti-inflammatory effects mediated by suppression of inflammatory gene expression.

  6. Peroxisome proliferator-activated receptor-γ coactivator-1α mediates neuroprotection against excitotoxic brain injury in transgenic mice: role of mitochondria and X-linked inhibitor of apoptosis protein.

    PubMed

    Mäkelä, Johanna; Mudò, Giuseppa; Pham, Dan Duc; Di Liberto, Valentina; Eriksson, Ove; Louhivuori, Lauri; Bruelle, Céline; Soliymani, Rabah; Baumann, Marc; Korhonen, Laura; Lalowski, Maciej; Belluardo, Natale; Lindholm, Dan

    2016-03-01

    Peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) is a transcriptional coactivator involved in the regulation of mitochondrial biogenesis and cell defense. The functions of PGC-1α in physiology of brain mitochondria are, however, not fully understood. To address this we have studied wild-type and transgenic mice with a two-fold overexpression of PGC-1α in brain neurons. Data showed that the relative number and basal respiration of brain mitochondria were increased in PGC-1α transgenic mice compared with wild-type mitochondria. These changes occurred concomitantly with altered levels of proteins involved in oxidative phosphorylation (OXPHOS) as studied by proteomic analyses and immunoblottings. Cultured hippocampal neurons from PGC-1α transgenic mice were more resistant to cell degeneration induced by the glutamate receptor agonist kainic acid. In vivo kainic acid induced excitotoxic cell death in the hippocampus at 48 h in wild-type mice but significantly less so in PGC-1α transgenic mice. However, at later time points cell degeneration was also evident in the transgenic mouse hippocampus, indicating that PGC-1α overexpression can induce a delay in cell death. Immunoblotting showed that X-linked inhibitor of apoptosis protein (XIAP) was increased in PGC-1α transgenic hippocampus with no significant changes in Bcl-2 or Bcl-X. Collectively, these results show that PGC-1α overexpression contributes to enhanced neuronal viability by stimulating mitochondria number and respiration and increasing levels of OXPHOS proteins and the anti-apoptotic protein XIAP. PMID:26741810

  7. The Peroxisomal Proliferator-Activated Receptor (PPAR) α Agonist, Fenofibrate, Prevents Fractionated Whole-Brain Irradiation-Induced Cognitive Impairment

    PubMed Central

    Greene-Schloesser, Dana; Payne, Valerie; Peiffer, Ann M.; Hsu, Fang-Chi; Riddle, David R.; Zhao, Weiling; Chan, Michael D.; Metheny-Barlow, Linda; Robbins, Mike E.

    2014-01-01

    We hypothesized that dietary administration of the peroxisomal proliferator-activated receptor α agonist, fenofibrate, to young adult male rats would prevent the fractionated whole-brain irradiation (fWBI)-induced reduction in cognitive function and neurogenesis and prevent the fWBI-induced increase in the total number of activated microglia. Eighty 12–14-week-old young adult male Fischer 344 × Brown Norway rats received either: (1) sham irradiation, (2) 40 Gy of fWBI delivered as two 5 Gy fractions/week for 4 weeks, (3) sham irradiation + dietary fenofibrate (0.2% w/w) starting 7 days prior to irradiation, or (4) fWBI + fenofibrate. Cognitive function was measured 26–29 weeks after irradiation using: (1) the perirhinal cortex (PRh)-dependent novel object recognition task; (2) the hippocampal-dependent standard Morris water maze (MWM) task; (3) the hippocampal-dependent delayed match-to-place version of the MWM task; and (4) a cue strategy preference version of the MWM to distinguish hippocampal from striatal task performance. Neurogenesis was assessed 29 weeks after fWBI in the granular cell layer and subgranular zone of the dentate gyrus using a doublecortin antibody. Microglial activation was assessed using an ED1 antibody in the dentate gyrus and hilus of the hippocampus. A significant impairment in perirhinal cortex-dependent cognitive function was measured after fWBI. In contrast, fWBI failed to alter hippocampal-dependent cognitive function, despite a significant reduction in hippocampal neurogenesis. Continuous administration of fenofibrate prevented the fWBI-induced reduction in perirhinal cortex-dependent cognitive function, but did not prevent the radiation-induced reduction in neurogenesis or the radiation-induced increase in activated microglia. These data suggest that fenofibrate may be a promising therapeutic for the prevention of some modalities of radiation-induced cognitive impairment in brain cancer patients. PMID:24397438

  8. Antioxidant cytoprotection by peroxisomal peroxiredoxin-5.

    PubMed

    Walbrecq, Geoffroy; Wang, Bo; Becker, Sarah; Hannotiau, Amandine; Fransen, Marc; Knoops, Bernard

    2015-07-01

    Peroxiredoxin-5 (PRDX5) is a thioredoxin peroxidase that reduces hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. This enzyme is present in the cytosol, mitochondria, peroxisomes, and nucleus in human cells. Antioxidant cytoprotective functions have been previously documented for cytosolic, mitochondrial, and nuclear mammalian PRDX5. However, the exact function of PRDX5 in peroxisomes is still not clear. The aim of this work was to determine the function of peroxisomal PRDX5 in mammalian cells and, more specifically, in glial cells. To study the role of PRDX5 in peroxisomes, the endogenous expression of PRDX5 in murine oligodendrocyte 158N cells was silenced by RNA interference. In addition, human PRDX5 was also overexpressed in peroxisomes using a vector coding for human PRDX5, whose unconventional peroxisomal targeting sequence 1 (PTS1; SQL) was replaced by the prototypical PTS1 SKL. Stable 158N clones were obtained. The antioxidant cytoprotective function of peroxisomal PRDX5 against peroxisomal and mitochondrial KillerRed-mediated reactive oxygen species production as well as H2O2 was examined using MTT viability assays, roGFP2, and C11-BOBIPY probes. Altogether our results show that peroxisomal PRDX5 protects 158N oligodendrocytes against peroxisomal and mitochondrial KillerRed- and H2O2-induced oxidative stress. PMID:25772011

  9. Peroxisome Proliferator-activated Receptor β/δ Induces Myogenesis by Modulating Myostatin Activity*

    PubMed Central

    Bonala, Sabeera; Lokireddy, Sudarsanareddy; Arigela, Harikumar; Teng, Serena; Wahli, Walter; Sharma, Mridula; McFarlane, Craig; Kambadur, Ravi

    2012-01-01

    Classically, peroxisome proliferator-activated receptor β/δ (PPARβ/δ) function was thought to be restricted to enhancing adipocyte differentiation and development of adipose-like cells from other lineages. However, recent studies have revealed a critical role for PPARβ/δ during skeletal muscle growth and regeneration. Although PPARβ/δ has been implicated in regulating myogenesis, little is presently known about the role and, for that matter, the mechanism(s) of action of PPARβ/δ in regulating postnatal myogenesis. Here we report for the first time, using a PPARβ/δ-specific ligand (L165041) and the PPARβ/δ-null mouse model, that PPARβ/δ enhances postnatal myogenesis through increasing both myoblast proliferation and differentiation. In addition, we have identified Gasp-1 (growth and differentiation factor-associated serum protein-1) as a novel downstream target of PPARβ/δ in skeletal muscle. In agreement, reduced Gasp-1 expression was detected in PPARβ/δ-null mice muscle tissue. We further report that a functional PPAR-responsive element within the 1.5-kb proximal Gasp-1 promoter region is critical for PPARβ/δ regulation of Gasp-1. Gasp-1 has been reported to bind to and inhibit the activity of myostatin; consistent with this, we found that enhanced secretion of Gasp-1, increased Gasp-1 myostatin interaction and significantly reduced myostatin activity upon L165041-mediated activation of PPARβ/δ. Moreover, we analyzed the ability of hGASP-1 to regulate myogenesis independently of PPARβ/δ activation. The results revealed that hGASP-1 protein treatment enhances myoblast proliferation and differentiation, whereas silencing of hGASP-1 results in defective myogenesis. Taken together these data revealed that PPARβ/δ is a positive regulator of skeletal muscle myogenesis, which functions through negatively modulating myostatin activity via a mechanism involving Gasp-1. PMID:22362769

  10. Multiple Peroxisomal Enzymatic Deficiency Disorders

    PubMed Central

    Vamecq, Joseph; Draye, Jean-Pierre; Van Hoof, Franois; Misson, Jean-Paul; Evrard, Philippe; Verellen, Gaston; Eyssen, Hendrik J.; Van Eldere, Johan; Schutgens, Ruud B. H.; Wanders, Ronald J. A.; Roels, Frank; Goldfischer, Sidney L.

    1986-01-01

    Biologic, morphologic, and biochemical investigations performed in 2 patients demonstrate multiple peroxisomal deficiencies in the cerebrohepatorenal syndrome of Zellweger (CHRS) and neonatal adrenoleukodystrophy (NALD). Very long chain fatty acids, abnormal bile acids, including bile acid precursors (di- and trihydroxycoprostanoic acids), and C29-dicarboxylic acid accumulated in plasma in both patients. Generalized hyperaminoaciduria was also present. Peroxisomes could not be detected in CHRS liver and kidney; however, in the NALD patient, small and sparse cytoplasmic bodies resembling altered peroxisomes were found in hepatocytes. Hepatocellular and Kupffer cell lysosomes were engorged with ferritin and contained clefts and trilaminar structures believed to represent very long chain fatty acids. Enzymatic deficiencies reflected the peroxisomal defects. Hepatic glycolate oxidase and palmitoyl-CoA oxidase activities were deficient. No particle-bound catalase was found in cultured fibroblasts, and ether glycerolipid (plasmalogen) biosynthesis was markedly reduced. Administration of phenobarbital and clofibrate, an agent that induces peroxisomal proliferation and enzymatic activities, to the NALD patient did not bring about any changes in plasma metabolites, liver peroxisome population, or oxidizing activities. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:2879480

  11. Decorin induces mitophagy in breast carcinoma cells via peroxisome proliferator-activated receptor ? coactivator-1? (PGC-1?) and mitostatin.

    PubMed

    Neill, Thomas; Torres, Annabel; Buraschi, Simone; Owens, Rick T; Hoek, Jan B; Baffa, Raffaele; Iozzo, Renato V

    2014-02-21

    Tumor cell mitochondria are key biosynthetic hubs that provide macromolecules for cancer progression and angiogenesis. Soluble decorin protein core, hereafter referred to as decorin, potently attenuated mitochondrial respiratory complexes and mitochondrial DNA (mtDNA) in MDA-MB-231 breast carcinoma cells. We found a rapid and dynamic interplay between peroxisome proliferator-activated receptor ? coactivator-1? (PGC-1?) and the decorin-induced tumor suppressor gene, mitostatin. This interaction stabilized mitostatin mRNA with concurrent accumulation of mitostatin protein. In contrast, siRNA-mediated abrogation of PGC-1?-blocked decorin-evoked stabilization of mitostatin. Mechanistically, PGC-1? bound MITOSTATIN mRNA to achieve rapid stabilization. These processes were orchestrated by the decorin/Met axis, as blocking the Met-tyrosine kinase or knockdown of Met abrogated these responses. Furthermore, depletion of mitostatin blocked decorin- or rapamycin-evoked mitophagy, increased vascular endothelial growth factor A (VEGFA) production, and compromised decorin-evoked VEGFA suppression. Collectively, our findings underscore the complexity of PGC-1?-mediated mitochondrial homeostasis and establish mitostatin as a key regulator of tumor cell mitophagy and angiostasis. PMID:24403067

  12. Peroxisome proliferator-activated receptor beta/delta activation improves angiotensin II-induced cardiac hypertrophy in vitro.

    PubMed

    Sheng, Li; Ye, Ping; Liu, Yong-Xue; Han, Chun-Guang; Zhang, Zhi-Yi

    2008-02-01

    Agonists of the peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (gamma) exert anti-proliferative and anti-inflammatory effects that led to the testing of these drugs in experimental cardiac hypertrophy. However, the effect of PPAR beta/delta (beta/delta) agonists in hypertrophy is not yet known. In this paper, an experiment was conducted to explore whether PPARbeta/delta activation has an effect on cardiac hypertrophy. An in vitro cardiomyocyte hypertrophy from neonatal rats was induced with Angiotensin II (Ang II1micromol x L(-1)) stimulation. For the examination of PPAR beta/delta effect, the cultured rat cardiac myocytes were pretreated with GW0742 (10 micromol.L(-1)), an agonist of PPARbeta/delta, for 48h before Ang II stimulation. The following parameters in the cultured cells were determined: surface areas of myocytes were measured by the NIH Image Software; (3)H-leucine incorporation into myocytes was counted by liquid scintillometer; mRNA expression of PPARbeta/delta, ANP, BNP, MMP9, MMP2, and IL-1beta was detected by RT-PCR; PPARbeta/delta protein expression was evaluated with immunofluorescence staining; GW0742 could ameliorate Ang II-induced cardiomyocyte hypertrophy, as indicated by its inhibitory effects on the surface area of myocytes, and ANP and BNP mRNA expressions in myocytes and (3)H-leucine incorporation into myocytes. Meanwhile, GW0742 pretreatment exerted inhibition on mRNA expression augmentation of such cytokines as MMP9, MMP2, and IL-1beta in hypertrophic myocytes. In addition, the down-regulated expression of PPARbeta/delta mRNA and protein in hypertrophic myocytes was also significantly reversed by GW0742. We demonstrate for the first time that GW0742 exerts a beneficial effect on Ang II-induced cardiac hypertrophy and the relation to inflammation response. PMID:18293166

  13. The methylotrophic yeast Hansenula polymorpha contains an inducible import pathway for peroxisomal matrix proteins with an N-terminal targeting signal (PTS2 proteins).

    PubMed Central

    Faber, K N; Haima, P; Gietl, C; Harder, W; Ab, G; Veenhuis, M

    1994-01-01

    Two main types of peroxisomal targeting signals have been identified that reside either at the extreme C terminus (PTS1) or the N terminus (PTS2) of the protein. In the methylotrophic yeast Hansenula polymorpha the majority of peroxisomal matrix proteins are of the PTS1 type. Thus far, for H. polymorpha only amine oxidase (AMO) has been shown to contain a PTS2 type signal. In the present study we expressed H. polymorpha AMO under control of the strong endogenous alcohol oxidase promoter. Partial import of AMO into peroxisomes was observed in cells grown in methanol/(NH4)2SO4-containing medium. However, complete import of AMO occurred if the cells were grown under conditions that induce expression of the endogenous AMO gene. Similar results were obtained when the heterologous PTS2 proteins, glyoxysomal malate dehydrogenase from watermelon and thiolase from Saccharomyces cerevisiae, were synthesized in H. polymorpha. The import of PTS1 proteins, however, was not affected by the growth conditions. These results indicate that the reduced rate of AMO import in (NH4)2SO4-grown cells is not due to competition with PTS1 proteins for the same import pathway. Apparently, AMO is imported via a separate pathway that is induced by amines and functions for PTS2 proteins in general. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7809160

  14. The methylotrophic yeast Hansenula polymorpha contains an inducible import pathway for peroxisomal matrix proteins with an N-terminal targeting signal (PTS2 proteins).

    PubMed

    Faber, K N; Haima, P; Gietl, C; Harder, W; Ab, G; Veenhuis, M

    1994-12-20

    Two main types of peroxisomal targeting signals have been identified that reside either at the extreme C terminus (PTS1) or the N terminus (PTS2) of the protein. In the methylotrophic yeast Hansenula polymorpha the majority of peroxisomal matrix proteins are of the PTS1 type. Thus far, for H. polymorpha only amine oxidase (AMO) has been shown to contain a PTS2 type signal. In the present study we expressed H. polymorpha AMO under control of the strong endogenous alcohol oxidase promoter. Partial import of AMO into peroxisomes was observed in cells grown in methanol/(NH4)2SO4-containing medium. However, complete import of AMO occurred if the cells were grown under conditions that induce expression of the endogenous AMO gene. Similar results were obtained when the heterologous PTS2 proteins, glyoxysomal malate dehydrogenase from watermelon and thiolase from Saccharomyces cerevisiae, were synthesized in H. polymorpha. The import of PTS1 proteins, however, was not affected by the growth conditions. These results indicate that the reduced rate of AMO import in (NH4)2SO4-grown cells is not due to competition with PTS1 proteins for the same import pathway. Apparently, AMO is imported via a separate pathway that is induced by amines and functions for PTS2 proteins in general. PMID:7809160

  15. Hypoxia-induced inhibition of lung development is attenuated by the peroxisome proliferator-activated receptor-? agonist rosiglitazone

    PubMed Central

    Nicola, Teodora; Zhang, Wei; James, Masheika L.; Rehan, Virender; Halloran, Brian; Olave, Nelida; Bulger, Arlene; Oparil, Suzanne; Chen, Yiu-Fai

    2011-01-01

    Hypoxia enhances transforming growth factor-? (TGF-?) signaling, inhibiting alveolar development and causing abnormal pulmonary arterial remodeling in the newborn lung. We hypothesized that, during chronic hypoxia, reduced peroxisome proliferator-activated receptor-? (PPAR-?) signaling may contribute to, or be caused by, excessive TGF-? signaling. To determine whether PPAR-? was reduced during hypoxia, C57BL/6 mice were exposed to hypoxia from birth to 2 wk and evaluated for PPAR-? mRNA and protein. To determine whether rosiglitazone (RGZ, a PPAR-? agonist) supplementation attenuated the effects of hypoxia, mice were exposed to air or hypoxia from birth to 2 wk in combination with either RGZ or vehicle, and measurements of lung histology, function, parameters related to TGF-? signaling, and collagen content were made. To determine whether excessive TGF-? signaling reduced PPAR-?, mice were exposed to air or hypoxia from birth to 2 wk in combination with either TGF-?-neutralizing antibody or vehicle, and PPAR-? signaling was evaluated. We observed that hypoxia reduced PPAR-? mRNA and protein, in association with impaired alveolarization, increased TGF-? signaling, reduced lung compliance, and increased collagen. RGZ increased PPAR-? signaling, with improved lung development and compliance in association with reduced collagen and TGF-? signaling. However, no reduction was noted in hypoxia-induced pulmonary vascular remodeling. Inhibition of hypoxia-enhanced TGF-? signaling increased PPAR-? signaling. These results suggest that hypoxia-induced inhibition of lung development is associated with a mutually antagonistic relationship between reduced PPAR-? and increased TGF-? signaling. PPAR-? agonists may be of potential therapeutic significance in attenuating TGF-? signaling and improving alveolar development. PMID:21531777

  16. Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

    PubMed Central

    Yanai, Hidekatsu; Masui, Yoshinori; Yoshikawa, Reo; Kunimatsu, Junwa; Kaneko, Hiroshi

    2010-01-01

    The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes. PMID:21537433

  17. Proton pump inhibitor-induced hypomagnesemic hypoparathyroidism

    PubMed Central

    Swaminathan, Krishnan

    2015-01-01

    Proton pump inhibitors are the one of the most widely used drugs in the world. Hypomagnesemic hypoparathyroidism has been reported with different proton pump inhibitors with prolonged oral use. We report the first reported case of possible such effect with intravenous preparation of proton pump inhibitor. This case report raises awareness among physicians worldwide of this often unknown association, as life-threatening cardiac and neuromuscular complications can arise with unrecognized hypocalcemia and hypomagnesemia with proton pump inhibitors. PMID:26069375

  18. Crosstalk between mitochondria and peroxisomes

    PubMed Central

    Demarquoy, Jean; Le Borgne, Françoise

    2015-01-01

    Mitochondria and peroxisomes are small ubiquitous organelles. They both play major roles in cell metabolism, especially in terms of fatty acid metabolism, reactive oxygen species (ROS) production, and ROS scavenging, and it is now clear that they metabolically interact with each other. These two organelles share some properties, such as great plasticity and high potency to adapt their form and number according to cell requirements. Their functions are connected, and any alteration in the function of mitochondria may induce changes in peroxisomal physiology. The objective of this paper was to highlight the interconnection and the crosstalk existing between mitochondria and peroxisomes. Special emphasis was placed on the best known connections between these organelles: origin, structure, and metabolic interconnections. PMID:26629313

  19. Peroxisome Proliferator-Activated Receptor ? and microRNA 98 in Hypoxia-Induced Endothelin-1 Signaling.

    PubMed

    Kang, Bum-Yong; Park, Kathy K; Kleinhenz, Jennifer M; Murphy, Tamara C; Green, David E; Bijli, Kaiser M; Yeligar, Samantha M; Carthan, Kristal A; Searles, Charles D; Sutliff, Roy L; Hart, C Michael

    2016-01-01

    Endothelin-1 (ET-1) plays a critical role in endothelial dysfunction and contributes to the pathogenesis of pulmonary hypertension (PH). We hypothesized that peroxisome proliferator-activated receptor ? (PPAR?) stimulates microRNAs that inhibit ET-1 and pulmonary artery endothelial cell (PAEC) proliferation. The objective of this study was to clarify molecular mechanisms by which PPAR? regulates ET-1 expression in vitro and in vivo. In PAECs isolated from patients with pulmonary arterial hypertension, microRNA (miR)-98 expression was reduced, and ET-1 protein levels and proliferation were increased. Similarly, hypoxia reduced miR-98 and increased ET-1 levels and PAEC proliferation in vitro. In vivo, hypoxia reduced miR-98 expression and increased ET-1 and proliferating cell nuclear antigen (PCNA) levels in mouse lung, derangements that were aggravated by treatment with the vascular endothelial growth factor receptor antagonist Sugen5416. Reporter assays confirmed that miR-98 binds directly to the ET-1 3'-untranslated region. Compared with littermate control mice, miR-98 levels were reduced and ET-1 and PCNA expression were increased in lungs from endothelial-targeted PPAR? knockout mice, whereas miR-98 levels were increased and ET-1 and PCNA expression was reduced in lungs from endothelial-targeted PPAR?-overexpression mice. Gain or loss of PPAR? function in PAECs in vitro confirmed that alterations in PPAR? were sufficient to regulate miR-98, ET-1, and PCNA expression. Finally, PPAR? activation with rosiglitazone regimens that attenuated hypoxia-induced PH in vivo and human PAEC proliferation in vitro restored miR-98 levels. The results of this study show that PPAR? regulates miR-98 to modulate ET-1 expression and PAEC proliferation. These results further clarify molecular mechanisms by which PPAR? participates in PH pathogenesis and therapy. PMID:26098770

  20. Peroxisome biogenesis: recent advances.

    PubMed

    Nuttall, James M; Motley, Alison; Hettema, Ewald H

    2011-08-01

    In recent years, it has become evident that peroxisomes form part of the endomembrane system. Peroxisomes can form from the ER via a maturation process and they can multiply by growth and division, whereby the ER provides membrane for growth and ongoing fission (Figure 1). Until very recently, it was widely accepted that most peroxisomal membrane proteins (PMPs) insert directly into peroxisomes, whereas a small subset of PMPs traffic via the ER. In this minireview, we focus mainly on PMP biogenesis, and highlight recent advances in peroxisomal matrix protein import, fission and segregation in yeast. PMID:21689915

  1. Signaling dynamics and peroxisomes.

    PubMed

    Mast, Fred D; Rachubinski, Richard A; Aitchison, John D

    2015-08-01

    Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function. PMID:26042681

  2. Ketogenic diet-induced peroxisome proliferator-activated receptor-? activation decreases neuroinflammation in the mouse hippocampus after kainic acid-induced seizures.

    PubMed

    Jeong, Eun Ae; Jeon, Byeong Tak; Shin, Hyun Joo; Kim, Nayoung; Lee, Dong Hoon; Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung; Roh, Gu Seob

    2011-12-01

    Similar to fasting, the ketogenic diet (KD) has anti-inflammatory effects and protects against excitotoxicity-mediated neuronal cell death. Recent studies have shown that peroxisome proliferator-activated receptor (PPAR)? has anti-inflammatory effects in seizure animal models. However, the exact mechanisms underlying the anti-inflammatory effects of the KD have not been determined for seizures. Here we investigated the effect of the KD and acetoacetate (AA) on neuroinflammation in a seizure animal model and glutamate-treated HT22 cells, respectively. Mice were fed the KD for 4 weeks and sacrificed 2 or 6h after KA injection. The KD reduced hippocampal tumor necrosis factor alpha (TNF-?) levels and nuclear factor (NF)-?B translocation into the nucleus 2h after KA treatment. KD-induced PPAR? activation was decreased by KA in neurons as assessed by western blotting and immunofluorescence. Finally, the KD inhibited cyclooxygenase (COX)-2 and microsomal prostaglandin E(2) synthase-1 (mPGES-1) expression in the hippocampus 6h after KA treatment. AA treatment also protected against glutamate-induced cell death in HT22 cells by reducing TNF-? and PPAR?-mediated COX-2 expression. Thus, the KD may inhibit neuroinflammation by suppressing a COX-2-dependent pathway via activation of PPAR? by the KD or AA. PMID:21939657

  3. ABCD2 Alters Peroxisome Proliferator-Activated Receptor ? Signaling In Vitro, but Does Not Impair Responses to Fenofibrate Therapy in a Mouse Model of Diet-Induced Obesity

    PubMed Central

    Liu, Xiaoxi; Liu, Jingjing; Liang, Shuang; Schlter, Agatha; Fourcade, Stephane; Aslibekyan, Stella; Pujol, Aurora

    2014-01-01

    Fenofibrate is a peroxisome proliferator-activated receptor (PPAR) ? ligand that has been widely used as a lipid-lowering agent in the treatment of hypertriglyceridemia. ABCD2 (D2) is a peroxisomal long-chain acyl-CoA transporter that is highly induced by fenofibrate in the livers of mice. To determine whether D2 is a modifier of fibrate responses, wild-type and D2-deficient mice were treated with fenofibrate for 14 days. The absence of D2 altered expression of gene clusters associated with lipid metabolism, including PPAR? signaling. Using 3T3-L1 adipocytes, which express high levels of D2, we confirmed that knockdown of D2 modified genomic responses to fibrate treatment. We next evaluated the impact of D2 on effects of fibrates in a mouse model of diet-induced obesity. Fenofibrate treatment opposed the development of obesity, hypertriglyceridemia, and insulin resistance. However, these effects were unaffected by D2 genotype. We concluded that D2 can modulate genomic responses to fibrates, but that these effects are not sufficiently robust to alter the effects of fibrates on diet-induced obesity phenotypes. PMID:25123288

  4. Characterization of hepatic mitochondrial injury induced by fatty acid oxidation inhibitors.

    PubMed

    Vickers, Alison E M

    2009-01-01

    Impairment of liver mitochondrial beta-oxidation is an important mechanism of drug-induced liver injury. Four inhibitors of fatty acid oxidation were compared in short-term rat in vivo studies in which the rats were administered one or four doses. The hepatocellular vacuolation represented ultra-structural mitochondrial changes. Urine nuclear magnetic resonance (NMR) spectroscopy revealed that both FOX988 and SDZ51-641 induced a persistent dicarboxylic aciduria, suggesting an inhibition of mitochondrial beta-oxidation and incomplete fatty acid metabolism. Etomoxir caused minimal mitochondrial ultrastructural changes and induced only transient dicarboxylic aciduria. CPI975 served as a negative control, in that there were no significant perturbations to the mitochondrial ultrastructural morphology or in the urine NMR composition; however, compound exposure was confirmed by the up-regulation of liver gene expression compared to vehicle control. The liver gene expression changes that were altered by the compounds were indicative of mitochondria, general and oxidative stress, and peroxisomal enzymes involved in beta-oxidation, suggestive of a compensatory response to the inhibition in the mitochondria. In addition, both FOX988 and SDZ51-641 up-regulated ribosomal genes associated with apoptosis, as well as p53 pathways linked with apoptosis. In summary, metabonomics and liver gene expression provided mechanistic information on mitochondrial dysfunction and impaired fatty acid oxidation to further define the clinical pathology and histopathology findings of hepatotoxicity. PMID:19234235

  5. Interleukin-6 inhibition of peroxisome proliferator-activated receptor alpha expression is mediated by JAK2- and PI3K-induced STAT1/3 in HepG2 hepatocyte cells.

    PubMed

    Chew, Guat-Siew; Myers, Stephen; Shu-Chien, Alexander Chong; Muhammad, Tengku Sifzizul Tengku

    2014-03-01

    Interleukin-6 (IL-6) is the major activator of the acute phase response (APR). One important regulator of IL-6-activated APR is peroxisome proliferator-activated receptor alpha (PPARα). Currently, there is a growing interest in determining the role of PPARα in regulating APR; however, studies on the molecular mechanisms and signaling pathways implicated in mediating the effects of IL-6 on the expression of PPARα are limited. We previously revealed that IL-6 inhibits PPARα gene expression through CAAT/enhancer-binding protein transcription factors in hepatocytes. In this study, we determined that STAT1/3 was the direct downstream molecules that mediated the Janus kinase 2 (JAK2) and phosphatidylinositol-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathways in IL-6-induced repression of PPARα. Treatment of cells with pharmacological inhibitors of JAK2, PI3K, AKT, and mTOR attenuated the inhibitory effect of IL-6 on PPARα protein in a dose-dependent manner. These inhibitors also decreased the IL-6-induced repression of PPARα mRNA expression and promoter activity. Overexpression of STAT1 and STAT3 in HepG2 cells cotransfected with a reporter vector containing this PPARα promoter region revealed that both the expression plasmids inhibited the IL-6-induced repression of PPARα promoter activity. In the presence of inhibitors of JAK2 and mTOR (AG490 and rapamycin, respectively), IL-6-regulated protein expression and DNA binding of STAT1 and STAT3 were either completely or partially inhibited simultaneously, and the IL-6-induced repression of PPARα protein and mRNA was also inhibited. This study has unraveled novel pathways by which IL-6 inhibits PPARα gene transcription, involving the modulation of JAK2/STAT1-3 and PI3K/AKT/mTOR by inducing the binding of STAT1 and STAT3 to STAT-binding sites on the PPARα promoter. Together, these findings represent a new model of IL-6-induced suppression of PPARα expression by inducing STAT1 and STAT3 phosphorylation and subsequent down-regulation of PPARα mRNA expression. PMID:24242046

  6. Peroxisome Biogenesis and Function

    PubMed Central

    Kaur, Navneet; Reumann, Sigrun; Hu, Jianping

    2009-01-01

    Peroxisomes are small and single membrane-delimited organelles that execute numerous metabolic reactions and have pivotal roles in plant growth and development. In recent years, forward and reverse genetic studies along with biochemical and cell biological analyses in Arabidopsis have enabled researchers to identify many peroxisome proteins and elucidate their functions. This review focuses on the advances in our understanding of peroxisome biogenesis and metabolism, and further explores the contribution of large-scale analysis, such as in sillco predictions and proteomics, in augmenting our knowledge of peroxisome function In Arabidopsis. PMID:22303249

  7. Peroxisomal APX knockdown triggers antioxidant mechanisms favourable for coping with high photorespiratory H2 O2 induced by CAT deficiency in rice.

    PubMed

    Sousa, Rachel H V; Carvalho, Fabricio E L; Ribeiro, Carol W; Passaia, Gisele; Cunha, Juliana R; Lima-Melo, Yugo; Margis-Pinheiro, Márcia; Silveira, Joaquim A G

    2015-03-01

    The physiological role of peroxisomal ascorbate peroxidases (pAPX) is unknown; therefore, we utilized pAPX4 knockdown rice and catalase (CAT) inhibition to assess its role in CAT compensation under high photorespiration. pAPX4 knockdown induced co-suppression in the expression of pAPX3. The rice mutants exhibited metabolic changes such as lower CAT and glycolate oxidase (GO) activities and reduced glyoxylate content; however, APX activity was not altered. CAT inhibition triggered different changes in the expression of CAT, APX and glutathione peroxidase (GPX) isoforms between non-transformed (NT) and silenced plants. These responses were associated with alterations in APX, GPX and GO activities, suggesting redox homeostasis differences. The glutathione oxidation-reduction states were modulated differently in mutants, and the ascorbate redox state was greatly affected in both genotypes. The pAPX suffered less oxidative stress and photosystem II (PSII) damage and displayed higher photosynthesis than the NT plants. The improved acclimation exhibited by the pAPX plants was indicated by lower H2 O2 accumulation, which was associated with lower GO activity and glyoxylate content. The suppression of both pAPXs and/or its downstream metabolic and molecular effects may trigger favourable antioxidant and compensatory mechanisms to cope with CAT deficiency. This physiological acclimation may involve signalling by peroxisomal H2 O2 , which minimized the photorespiration. PMID:25039271

  8. Akt inhibitors induce apoptosis in chronic lymphocytic leukemia cells

    PubMed Central

    de Frias, Mercè; Iglesias-Serret, Daniel; Cosialls, Ana M.; Coll-Mulet, Llorenç; Santidrián, Antonio F.; González-Gironès, Diana M.; de la Banda, Esmeralda; Pons, Gabriel; Gil, Joan

    2009-01-01

    Background The phosphatidylinositol-3-kinase/Akt pathway has been described to be critical in the survival of chronic lymphocytic leukemia cells. In this study we analyzed the effect of two selective chemical inhibitors of Akt (Akti-1/2 and A-443654) on the survival of chronic lymphocytic leukemia cells. Design and Methods Using cytometry we studied the cytotoxic effects of Akt inhibitors on peripheral B and T lymphocytes from patients with chronic lymphocytic leukemia and from healthy donors. We studied the changes induced by Akti-1/2 and A-443654 at the mRNA level by performing reverse transcriptase multiplex ligation–dependent probe amplification. We also studied the changes induced by both Akt inhibitors in some BCL-2 protein family members on chronic lymphocytic leukemia cells by western blotting. Moreover, we analyzed the cytotoxic effect of Akt inhibitors in patients’ cells with deleted/mutated TP53. Results Both inhibitors induced apoptosis in chronic lymphocytic leukemia cells in a dose-dependent manner. Moreover, B cells from patients with chronic lymphocytic leukemia were more sensitive to Akt inhibitors than T cells from leukemic patients, and B or T cells from healthy donors. Survival factors for chronic lymphocytic leukemia cells, such as interleukin-4 and stromal cell-derived factor-1α, were not able to block the apoptosis induced by either Akt inhibitor. Akti-1/2 did not induce any change in the mRNA expression profile of genes involved in apoptosis, while A-443654 induced some changes, including an increase in NOXA and PUMA mRNA levels, suggesting the existence of additional targets for A-443654. Both inhibitors induced an increase in PUMA and NOXA protein levels, and a decrease in MCL-1 protein level. Moreover, Akti-1/2 and A-443654 induced apoptosis irrespective of TP53 status. Conclusions These results demonstrate that Akt inhibitors induce apoptosis of chronic lymphocytic leukemia cells and might be a new therapeutic option for the treatment of chronic lymphocytic leukemia. PMID:19815839

  9. Wogonin prevents lipopolysaccharide-induced acute lung injury and inflammation in mice via peroxisome proliferator-activated receptor gamma-mediated attenuation of the nuclear factor-kappaB pathway.

    PubMed

    Yao, Jing; Pan, Di; Zhao, Yue; Zhao, Li; Sun, Jie; Wang, Yu; You, Qi-Dong; Xi, Tao; Guo, Qing-Long; Lu, Na

    2014-10-01

    Acute lung injury (ALI) from a variety of clinical disorders, characterized by diffuse inflammation, is a cause of acute respiratory failure that develops in patients of all ages. Previous studies reported that wogonin, a flavonoid-like chemical compound which was found in Scutellaria baicalensis, has anti-inflammatory effects in several inflammation models, but not in ALI. Here, the in vivo protective effect of wogonin in the amelioration of lipopolysaccharide (LPS) -induced lung injury and inflammation was assessed. In addition, the in vitro effects and mechanisms of wogonin were studied in the mouse macrophage cell lines Ana-1 and RAW264.7. In vivo results indicated that wogonin attenuated LPS-induced histological alterations. Peripheral blood leucocytes decreased in the LPS-induced group, which was ameliorated by wogonin. In addition, wogonin inhibited the production of several inflammatory cytokines, including tumour necrosis factor-?, interleukin-1? (IL-1?) and IL-6, in the bronchoalveolar lavage fluid and lung tissues after LPS challenge, while the peroxisome proliferator-activated receptor ? (PPAR?) inhibitor GW9662 reversed these effects. In vitro results indicated that wogonin significantly decreased the secretion of IL-6, IL-1? and tumour necrosis factor-? in Ana-1 and RAW264.7 cells, which was suppressed by transfection of PPAR? small interfering RNA and GW9662 treatment. Moreover, wogonin activated PPAR?, induced PPAR?-mediated attenuation of the nuclear translocation and the DNA-binding activity of nuclear factor-?B in vivo and in vitro. In conclusion, all of these results showed that wogonin may serve as a promising agent for the attenuation of ALI-associated inflammation and pathology by regulating the PPAR?-involved nuclear factor-?B pathway. PMID:24766487

  10. Epigenetic Activity of Peroxisome Proliferator-Activated Receptor Gamma Agonists Increases the Anticancer Effect of Histone Deacetylase Inhibitors on Multiple Myeloma Cells

    PubMed Central

    Aouali, Nassera; Broukou, Angeliki; Bosseler, Manon; Keunen, Olivier; Schlesser, Vincent; Janji, Bassam; Palissot, Valerie; Stordeur, Philippe; Berchem, Guy

    2015-01-01

    Epigenetic modifications play a major role in the development of multiple myeloma. We have previously reported that the PPAR? agonist pioglitazone (PIO) enhances, in-vitro, the cytotoxic effect of the Histone deacetylase inhibitor (HDACi), valproic acid (VPA), on multiple myeloma cells. Here, we described the development of a new multiple myeloma mouse model using MOLP8 cells, in order to evaluate the effect of VPA/PIO combination on the progression of myeloma cells, by analyzing the proliferation of bone marrow plasma cells. We showed that VPA/PIO delays the progression of the disease and the invasion of myeloma cells in the bone marrow. Mechanistically, we demonstrated that VPA/PIO increases the cleavage of caspase 3 and PARP, and induces the acetylation of Histone 3 (H3). Furthermore, we provided evidence that PPAR? agonist is able to enhance the action of other HDACi such as Vorinostat or Mocetinostat. Using PPAR? antagonist or siPPAR?, we strongly suggest that, as described during adipogenesis, PIO behaves as an epigenetic regulator by improving the activity of HDACi. This study highlights the therapeutic benefit of PIO/VPA combination, compared to VPA treatment as a single-arm therapy on multiple myeloma and further highlights that such combination may constitute a new promising treatment strategy which should be supported by clinical trials. PMID:26091518

  11. Characterization of endoproteases from plant peroxisomes.

    PubMed Central

    Distefano, S; Palma, J M; Gmez, M; Ro, L A

    1997-01-01

    In this work, the characterization of endoprotease (EP) isoenzymes in peroxisomes is reported for the first time in cell organelles purified from pea leaves (Pisum sativum L.). A comparative analysis of the endo-proteolytic activity in peroxisomes purified from young (15-day-old) and senescent (50-day-old) leaves was carried out. Peroxisomes purified from senescent leaves showed a much higher endo-proteolytic activity than organelles from young plants. A 16 h incubation with exogenous substrates was the threshold time for the detection of a linear increase in the endo-proteolytic activity of peroxisomes from senescent leaves. Three EP isoenzymes (EP2, EP4 and EP5), having molecular masses of 88, 64 and 50 kDa respectively, were found in young plants by using SDS/polyacrylamide-gradient gels co-polymerized with gelatin. However, four additional isoenzymes (EP1, EP3, EP6 and EP7), with molecular masses of 220, 76, 46 and 34 kDa respectively, were detected in senescent plants. All the isoenzymes detected in peroxisomes from both young and senescent leaves were neutral proteases. By using different class-specific inhibitors, the electrophoretically separated EP isoenzymes were characterized as three serine-proteinases (EP1, EP3 and EP4), two cysteine-proteinases (EP2 and EP6) and a metallo-proteinase (EP7), and EP5 might be a metal-dependent serine-proteinase. Moreover, a peroxisomal polypeptide of 64 kDa was recognized by an antibody against a thiol-protease. The serine-proteinase isoenzymes (EP1, EP3 and EP4), which represent approx. 70% of the total EP activity of peroxisomes, showed a notable thermal stability, not being inhibited by incubation at 50 degrees C for 1 h. PMID:9359407

  12. Arabidopsis peroxisome proteomics

    PubMed Central

    Bussell, John D.; Behrens, Christof; Ecke, Wiebke; Eubel, Holger

    2013-01-01

    The analytical depth of investigation of the peroxisomal proteome of the model plant Arabidopsis thaliana has not yet reached that of other major cellular organelles such as chloroplasts or mitochondria. This is primarily due to the difficulties associated with isolating and obtaining purified samples of peroxisomes from Arabidopsis. So far only a handful of research groups have been successful in obtaining such fractions. To make things worse, enriched peroxisome fractions frequently suffer from significant organellar contamination, lowering confidence in localization assignment of the identified proteins. As with other cellular compartments, identification of peroxisomal proteins forms the basis for investigations of the dynamics of the peroxisomal proteome. It is therefore not surprising that, in terms of functional analyses by proteomic means, peroxisomes are lagging considerably behind chloroplasts or mitochondria. Alternative strategies are needed to overcome the obstacle of hard-to-obtain organellar fractions. This will help to close the knowledge gap between peroxisomes and other organelles and provide a full picture of the physiological pathways shared between organelles. In this review, we briefly summarize the status quo and discuss some of the methodological alternatives to classic organelle proteomic approaches. PMID:23630535

  13. The Nox4 inhibitor GKT137831 attenuates hypoxia-induced pulmonary vascular cell proliferation.

    PubMed

    Green, David E; Murphy, Tamara C; Kang, Bum-Yong; Kleinhenz, Jennifer M; Szyndralewiez, Cdric; Page, Patrick; Sutliff, Roy L; Hart, C Michael

    2012-11-01

    Increased NADP reduced (NADPH) oxidase 4 (Nox4) and reduced expression of the nuclear hormone receptor peroxisome proliferator-activated receptor ? (PPAR?) contribute to hypoxia-induced pulmonary hypertension (PH). To examine the role of Nox4 activity in pulmonary vascular cell proliferation and PH, the current study used a novel Nox4 inhibitor, GKT137831, in hypoxia-exposed human pulmonary artery endothelial or smooth muscle cells (HPAECs or HPASMCs) in vitro and in hypoxia-treated mice in vivo. HPAECs or HPASMCs were exposed to normoxia or hypoxia (1% O(2)) for 72 hours with or without GKT137831. Cell proliferation and Nox4, PPAR?, and transforming growth factor (TGF)?1 expression were measured. C57Bl/6 mice were exposed to normoxia or hypoxia (10% O(2)) for 3 weeks with or without GKT137831 treatment during the final 10 days of exposure. Lung PPAR? and TGF-?1 expression, right ventricular hypertrophy (RVH), right ventricular systolic pressure (RVSP), and pulmonary vascular remodeling were measured. GKT137831 attenuated hypoxia-induced H(2)O(2) release, proliferation, and TGF-?1 expression and blunted reductions in PPAR? in HPAECs and HPASMCs in vitro. In vivo GKT137831 inhibited hypoxia-induced increases in TGF-?1 and reductions in PPAR? expression and attenuated RVH and pulmonary artery wall thickness but not increases in RVSP or muscularization of small arterioles. This study shows that Nox4 plays a critical role in modulating proliferative responses of pulmonary vascular wall cells. Targeting Nox4 with GKT137831 provides a novel strategy to attenuate hypoxia-induced alterations in pulmonary vascular wall cells that contribute to vascular remodeling and RVH, key features involved in PH pathogenesis. PMID:22904198

  14. The Nox4 Inhibitor GKT137831 Attenuates Hypoxia-Induced Pulmonary Vascular Cell Proliferation

    PubMed Central

    Green, David E.; Murphy, Tamara C.; Kang, Bum-Yong; Kleinhenz, Jennifer M.; Szyndralewiez, Cdric; Page, Patrick; Sutliff, Roy L.

    2012-01-01

    Increased NADP reduced (NADPH) oxidase 4 (Nox4) and reduced expression of the nuclear hormone receptor peroxisome proliferator-activated receptor ? (PPAR?) contribute to hypoxia-induced pulmonary hypertension (PH). To examine the role of Nox4 activity in pulmonary vascular cell proliferation and PH, the current study used a novel Nox4 inhibitor, GKT137831, in hypoxia-exposed human pulmonary artery endothelial or smooth muscle cells (HPAECs or HPASMCs) in vitro and in hypoxia-treated mice in vivo. HPAECs or HPASMCs were exposed to normoxia or hypoxia (1% O2) for 72 hours with or without GKT137831. Cell proliferation and Nox4, PPAR?, and transforming growth factor (TGF)?1 expression were measured. C57Bl/6 mice were exposed to normoxia or hypoxia (10% O2) for 3 weeks with or without GKT137831 treatment during the final 10 days of exposure. Lung PPAR? and TGF-?1 expression, right ventricular hypertrophy (RVH), right ventricular systolic pressure (RVSP), and pulmonary vascular remodeling were measured. GKT137831 attenuated hypoxia-induced H2O2 release, proliferation, and TGF-?1 expression and blunted reductions in PPAR? in HPAECs and HPASMCs in vitro. In vivo GKT137831 inhibited hypoxia-induced increases in TGF-?1 and reductions in PPAR? expression and attenuated RVH and pulmonary artery wall thickness but not increases in RVSP or muscularization of small arterioles. This study shows that Nox4 plays a critical role in modulating proliferative responses of pulmonary vascular wall cells. Targeting Nox4 with GKT137831 provides a novel strategy to attenuate hypoxia-induced alterations in pulmonary vascular wall cells that contribute to vascular remodeling and RVH, key features involved in PH pathogenesis. PMID:22904198

  15. Expression regulation and targeting of the peroxisome proliferator-activated receptor ? following electrically-induced status epilepticus.

    PubMed

    Boes, Katharina; Russmann, Vera; Ongerth, Tanja; Licko, Thomas; Salvamoser, Josephine D; Siegl, Claudia; Potschka, Heidrun

    2015-09-14

    The neuroprotective and anti-inflammatory effects of the peroxisome proliferator-activated receptor ? (PPAR?) agonist rosiglitazone are of particular interest for disease-modifying and antiepileptogenic approaches. We studied the expression of PPAR? and the impact of rosiglitazone on the consequences of status epilepticus (SE) in a rat post-SE model. Immunohistochemical analysis revealed a selective overexpression of PPAR? in the piriform cortex of rats with spontaneous seizures. Rosiglitazone administration initiated following SE failed to exert relevant effects on the development of spontaneous seizures and neuronal cell loss. Whereas spatial learning in the Morris water maze was delayed in SE animals with vehicle administration, the learning curve of rosiglitazone-treated SE rats showed no significant difference to that of controls. The study provides first evidence arguing against a robust antiepileptogenic effect. However, the findings in the spatial learning paradigm indicate disease-modifying effects. PMID:26259695

  16. Peroxisomal ABC transporters.

    PubMed

    Theodoulou, Frederica L; Holdsworth, Michael; Baker, Alison

    2006-02-13

    Peroxisomes perform a range of different functions, dependent upon organism, tissue type, developmental stage or environmental conditions, many of which are connected with lipid metabolism. This review summarises recent research on ATP binding cassette (ABC) transporters of the peroxisomal membrane (ABC subfamily D) and their roles in plants, fungi and animals. Analysis of mutants has revealed that peroxisomal ABC transporters play key roles in specific metabolic and developmental functions in different organisms. A common function is import of substrates for beta-oxidation but much remains to be determined concerning transport substrates and mechanisms which appear to differ significantly between phyla. PMID:16413537

  17. Tyrosine Kinase Inhibitor Induced Isolated Pericardial Effusion

    PubMed Central

    Agrawal, Vineet; Christenson, Eric S.; Showel, Margaret M.

    2015-01-01

    Long-term therapy with tyrosine kinase inhibitors (TKI) has resulted in improved outcomes for patients suffering from Bcr-Abl fusion protein-harboring leukemias. As a result, a growing population of patients on TKI therapy present to their primary care providers. In this case, we report on the case of a 62-year-old male who presented with a symptomatic pericardial effusion. After pericardiocentesis, malignancy and infectious etiologies were excluded. The pericardial effusion was attributed to his TKI, with a transition of this medication to a different TKI. A repeat evaluation 1 month following the withdrawal of the offending agent showed no recurrence of his pericardial effusion on echocardiogram. In this report, we will highlight a rare but important side effect of TKI therapy before discussing its purported mechanisms and differing incidence rates. Early recognition of serosal inflammation related to long-term TKI therapy by primary care providers is important in preventing patient morbidity and mortality. PMID:25848358

  18. Inhibitors of Fatty Acid Synthesis Induce PPAR ? -Regulated Fatty Acid ? -Oxidative Genes: Synergistic Roles of L-FABP and Glucose.

    PubMed

    Huang, Huan; McIntosh, Avery L; Martin, Gregory G; Petrescu, Anca D; Landrock, Kerstin K; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm

    2013-01-01

    While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor- ? (PPAR ? ) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20?mM) but not physiological (6?mM) glucose conferred on both TOFA and C75 the ability to induce PPAR ? transcription of the fatty acid ? -oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR ? in the context of high glucose at levels similar to those in uncontrolled diabetes. PMID:23533380

  19. Potentially lethal ACE-inhibitor-induced angioedema in a child.

    PubMed

    Bukhari, Esraa; Safdar, Osama Y; Shalaby, Mohammed; AlSharif, Shafiqa Mj; Alsufiany, Khoulod; Kari, Jameela A

    2015-06-01

    We report a case of a 9-year-old female with known end-stage kidney disease who presented with sudden onset tongue swelling. A diagnosis of angiotensin-converting enzyme inhibitor-induced angioedema related to bradykinin accumulation was made. Her symptoms resolved shortly after discontinuation of captopril. Early diagnosis can save patients from severe upper airway obstruction. PMID:26185642

  20. The Role of Peroxisome Proliferator-activated Receptor Gamma Coactivator 1 beta (PGC-1?) in the Pathogenesis of Fructose-Induced Insulin Resistance

    PubMed Central

    Nagai, Yoshio; Yonemitsu, Shin; Erion, Derek M.; Iwasaki, Takanori; Stark, Romana; Weismann, Dirk; Dong, Jianying; Zhang, Dongyan; Jurczak, Michael J.; Lffler, Michael G.; Cresswell, James; Yu, Xing Xian; Murray, Susan F.; Bhanot, Sanjay; Monia, Brett P.; Bogan, Jonathan S.; Samuel, Varman; Shulman, Gerald I.

    2011-01-01

    Summary Peroxisome proliferator-activated receptor-gamma coactivator 1 beta (PGC-1?) is known to be a transcriptional coactivator for SREBP-1, the master regulator of hepatic lipogenesis. Here we evaluated the role of PGC-1? in the pathogenesis of fructose-induced insulin resistance by using an antisense oligonucletoide (ASO) to knockdown PGC-1 ? in liver and adipose tissue. PGC-1 ? ASO improved the metabolic phenotype induced by fructose feeding by reducing expression of SREBP-1 and downstream lipogenic genes in liver. PGC-1 ? ASO also reversed hepatic insulin resistance induced by fructose in both basal and insulin stimulated states. Furthermore, PGC-1? ASO increased insulin-stimulated whole body glucose disposal due to a threefold increase in glucose uptake in white adipose tissue. These data support an important role for PGC-1 ? in the pathogenesis of fructose-induced insulin resistance and suggest that PGC-1 ? inhibition may be a novel therapeutic target for treatment of NAFLD, hypertriglyceridemia and insulin resistance associated with increased de novo lipogenesis. PMID:19254570

  1. Danhong inhibits oxidized low-density lipoprotein-induced immune maturation of dentritic cells via a peroxisome proliferator activated receptor ?-mediated pathway.

    PubMed

    Liu, Hongying; Wang, Shijun; Sun, Aijun; Huang, Dong; Wang, Wei; Zhang, Chunyu; Shi, Dazhuo; Chen, Keji; Zou, Yunzeng; Ge, Junbo

    2012-01-01

    Danhong injection (DHI), a Chinese Materia Medica standardized product extracted from Radix Salviae miltiorrhizae and Flos Carthami tinctorii, is effective in the treatment of atherosclerosis (AS)-related diseases. It is widely recognized that AS is a complex inflammatory disease of the arterial wall and the dendritic cells (DCs) is a major player in the pathogenesis of AS via mediating atherosclerotic antigen presenting and T lymphocytes. Here, we determined the effect and possible mechanism of DHI on oxidized low-density lipoprotein (ox-LDL)-induced maturation and immune function of DCs. Human monocyte-derived DCs were incubated with DHI or ciglitazone and were subsequently stimulated with ox-LDL to induce maturation. Similar to ciglitazone, a peroxisome proliferator activated receptor (PPAR) ? agonist, DHI, could significantly reduce ox-LDL-induced expressions of mature markers, enhance the endocytotic function, and inhibit secretions of cytokine on DCs. These effects of DHI could be partly reversed by silencing the PPAR?. In conclusion, DHI could inhibit ox-LDL-induced maturation of DCs partly through activating a PPAR?-mediated signaling pathway. PMID:22739234

  2. Activation of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) induces cell death through MAPK-dependent mechanism in osteoblastic cells

    SciTech Connect

    Kim, Sung Hun; Yoo, Chong Il; Kim, Hui Taek; Park, Ji Yeon; Kwon, Chae Hwa; Keun Kim, Yong . E-mail: kim430@pusan.ac.kr

    2006-09-01

    The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPAR{gamma} agonists in osteoblastic cells. Ciglitazone and troglitazone, PPAR{gamma} agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPAR{alpha} agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPAR{gamma} antagonist GW9662. Ciglitazone treatment caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis.

  3. Peroxisomes Get Loud: A Redox Antidote to Hearing Loss.

    PubMed

    Mardones, Pablo; Hetz, Claudio

    2015-11-01

    Pejvakin (PJVK), a protein originally identified in Persian families with sensorineural hearing loss, regulates peroxisomal dynamics and the antioxidant defense triggered by noise exposure in hair cells and auditory neurons of the inner ear. These findings bring peroxisomes to the forefront of noise-induced hearing loss research. PMID:26544930

  4. Isorhamnetin Inhibits Proliferation and Invasion and Induces Apoptosis through the Modulation of Peroxisome Proliferator-activated Receptor ? Activation Pathway in Gastric Cancer*

    PubMed Central

    Ramachandran, Lalitha; Manu, Kanjoormana Aryan; Shanmugam, Muthu K.; Li, Feng; Siveen, Kodappully Sivaraman; Vali, Shireen; Kapoor, Shweta; Abbasi, Taher; Surana, Rohit; Smoot, Duane T.; Ashktorab, Hassan; Tan, Patrick; Ahn, Kwang Seok; Yap, Chun Wei; Kumar, Alan Prem; Sethi, Gautam

    2012-01-01

    Gastric cancer (GC) is a lethal malignancy and the second most common cause of cancer-related deaths. Although treatment options such as chemotherapy, radiotherapy, and surgery have led to a decline in the mortality rate due to GC, chemoresistance remains as one of the major causes for poor prognosis and high recurrence rate. In this study, we investigated the potential effects of isorhamnetin (IH), a 3?-O-methylated metabolite of quercetin on the peroxisome proliferator-activated receptor ? (PPAR-?) signaling cascade using proteomics technology platform, GC cell lines, and xenograft mice model. We observed that IH exerted a strong antiproliferative effect and increased cytotoxicity in combination with chemotherapeutic drugs. IH also inhibited the migratory/invasive properties of GC cells, which could be reversed in the presence of PPAR-? inhibitor. We found that IH increased PPAR-? activity and modulated the expression of PPAR-? regulated genes in GC cells. Also, the increase in PPAR-? activity was reversed in the presence of PPAR-?-specific inhibitor and a mutated PPAR-? dominant negative plasmid, supporting our hypothesis that IH can act as a ligand of PPAR-?. Using molecular docking analysis, we demonstrate that IH formed interactions with seven polar residues and six nonpolar residues within the ligand-binding pocket of PPAR-? that are reported to be critical for its activity and could competitively bind to PPAR-?. IH significantly increased the expression of PPAR-? in tumor tissues obtained from xenograft model of GC. Overall, our findings clearly indicate that antitumor effects of IH may be mediated through modulation of the PPAR-? activation pathway in GC. PMID:22992727

  5. Hypoxia inducible factor pathway inhibitors as anticancer therapeutics

    PubMed Central

    Burroughs, Sarah K; Kaluz, Stefan; Wang, Danzhu; Wang, Ke

    2013-01-01

    Hypoxia is a significant feature of solid tumor cancers. Hypoxia leads to a more malignant phenotype that is resistant to chemotherapy and radiation, is more invasive and has greater metastatic potential. Hypoxia activates the hypoxia inducible factor (HIF) pathway, which mediates the biological effects of hypoxia in tissues. The HIF complex acts as a transcription factor for many genes that increase tumor survival and proliferation. To date, many HIF pathway inhibitors indirectly affect HIF but there have been no clinically approved direct HIF inhibitors. This can be attributed to the complexity of the HIF pathway, as well as to the challenges of inhibiting protein–protein interactions. PMID:23573973

  6. Ginger extract prevents high-fat diet-induced obesity in mice via activation of the peroxisome proliferator-activated receptor ? pathway.

    PubMed

    Misawa, Koichi; Hashizume, Kojiro; Yamamoto, Masaki; Minegishi, Yoshihiko; Hase, Tadashi; Shimotoyodome, Akira

    2015-10-01

    The initiation of obesity entails an imbalance wherein energy intake exceeds expenditure. Obesity is increasing in prevalence and is now a worldwide health problem. Food-derived peroxisome proliferator-activated receptor ? (PPAR?) stimulators represent potential treatment options for obesity. Ginger (Zingiber officinale Roscoe) was previously shown to regulate the PPAR? signaling pathway in adipocytes. In this study, we investigated the antiobesity effects of ginger in vivo and the mechanism of action in vitro. Energy expenditure was increased, and diet-induced obesity was attenuated in C57BL/6J mice treated with dietary ginger extract (GE). GE also increased the number of Type I muscle fibers, improved running endurance capacity and upregulated PPAR?-targeted gene expression in skeletal muscle and the liver. 6-Shogaol and 6-gingerol acted as specific PPAR? ligands and stimulated PPAR?-dependent gene expression in cultured human skeletal muscle myotubes. An analysis of cellular respiration revealed that pretreating cultured skeletal muscle myotubes with GE increased palmitate-induced oxygen consumption rate, which suggested an increase in cellular fatty acid catabolism. These results demonstrated that sustained activation of the PPAR? pathway with GE attenuated diet-induced obesity and improved exercise endurance capacity by increasing skeletal muscle fat catabolism. 6-Shogaol and 6-gingerol may be responsible for the regulatory effects of dietary ginger on PPAR? signaling. PMID:26101135

  7. Constitutive active/androstane receptor, peroxisome proliferator-activated receptor ?, and cytotoxicity are involved in oxadiazon-induced liver tumor development in mice.

    PubMed

    Kuwata, Kazunori; Inoue, Kaoru; Ichimura, Ryohei; Takahashi, Miwa; Kodama, Yukio; Yoshida, Midori

    2016-02-01

    Oxadiazon (OX) is a protoporphyrinogen oxidase-inhibiting herbicide that induces porphyria and liver tumors in rodents. Although porphyria is generally considered to be a risk factor for liver tumor development, the mechanisms through which OX mediates tumor development are unclear. Therefore, in this study, we investigated the mechanisms of tumor development by focusing on constitutive active/androstane receptor (CAR), which is essential for the development of tumors in response to several chemicals. After 1, 4, or 13 weeks of dietary treatment with 1000ppm OX, hepatic Cyp2b10 expression was induced in wild-type (WT) mice. However, this effect was blocked in CAR-knockout (CARKO) mice. Hepatic Cyp4a10 expression, indicative of peroxisome proliferator-activated receptor ? (PPAR?) activation, and cytotoxic changes in hepatocytes were also observed in both groups of mice. After initiation by diethylnitrosamine, 26-week treatment with OX resulted in an increase in proliferative lesions, including foci and adenomas, in both genotypes, and the incidence and multiplicity of proliferative lesions in CARKO mice were higher than those in control mice but lower than those in WT mice. These results suggested that CAR, PPAR? activation, and cytotoxicity were involved in the development of liver tumors. Moreover, porphyrin was not apparently involved in OX-induced tumor development. PMID:26710982

  8. Administration of the peroxisomal proliferator-activated receptor {gamma} agonist pioglitazone during fractionated brain irradiation prevents radiation-induced cognitive impairment

    SciTech Connect

    Zhao Weiling; Payne, Valerie; Tommasi, Ellen; Diz, Debra I.; Hsu, F.-C.; Robbins, Mike E. . E-mail: mrobbins@wfubmc.edu

    2007-01-01

    Purpose: We hypothesized that administration of the anti-inflammatory peroxisomal proliferator-activated receptor {gamma} (PPAR{gamma}) agonist pioglitazone (Pio) to adult male rats would inhibit radiation-induced cognitive impairment. Methods and Materials: Young adult male F344 rats received one of the following: (1) fractionated whole brain irradiation (WBI); 40 or 45 Gy {gamma}-rays in 4 or 4.5 weeks, respectively, two fractions per week and normal diet; (2) sham-irradiation and normal diet; (3) WBI plus Pio (120 ppm) before, during, and for 4 or 54 weeks postirradiation; (4) sham-irradiation plus Pio; or (5) WBI plus Pio starting 24h after completion of WBI. Results: Administration of Pio before, during, and for 4 or 54 weeks after WBI prevented Radiation-induced cognitive impairment. Administration of Pio for 54 weeks starting after completion of fractionated WBI substantially but not significantly reduced Radiation-induced cognitive impairment. Conclusions: These findings offer the promise of improving the quality of life and increasing the therapeutic window for brain tumor patients.

  9. Activation of peroxisome proliferator-activated receptor ? induces lysosomal biogenesis in brain cells: implications for lysosomal storage disorders.

    PubMed

    Ghosh, Arunava; Jana, Malabendu; Modi, Khushbu; Gonzalez, Frank J; Sims, Katherine B; Berry-Kravis, Elizabeth; Pahan, Kalipada

    2015-04-17

    Lysosomes are ubiquitous membrane-enclosed organelles filled with an acidic interior and are central to the autophagic, endocytic, or phagocytic pathway. In contrast to its classical function as the waste management machinery, lysosomes are now considered to be an integral part of various cellular signaling processes. The diverse functionality of this single organelle requires a very complex and coordinated regulation of its activity with transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, at its core. However, mechanisms by which TFEB is regulated are poorly understood. This study demonstrates that gemfibrozil, an agonist of peroxisome proliferator-activated receptor (PPAR) ?, alone and in conjunction with all-trans-retinoic acid is capable of enhancing TFEB in brain cells. We also observed that PPAR?, but not PPAR? and PPAR?, is involved in gemfibrozil-mediated up-regulation of TFEB. Reporter assay and chromatin immunoprecipitation studies confirmed the recruitment of retinoid X receptor ?, PPAR?, and PGC1? on the PPAR-binding site on the Tfeb promoter as well. Subsequently, the drug-mediated induction of TFEB caused an increase in lysosomal protein and the lysosomal abundance in cell. Collectively, this study reinforces the link between lysosomal biogenesis and lipid metabolism with TFEB at the crossroads. Furthermore, gemfibrozil may be of therapeutic value in the treatment of lysosomal storage disorders in which autophagy-lysosome pathway plays an important role. PMID:25750174

  10. Light control of peroxisome proliferation during Arabidopsis photomorphogenesis

    PubMed Central

    Desai, Mintu

    2008-01-01

    Peroxisomes are multifunctional organelles whose abundance and metabolic activities differ depending on the species, cell type, developmental stage and prevailing environmental conditions.1 However, little is known about the signaling pathways that control these variations, especially in plants. Our laboratory recently investigated the regulatory role of light in changes in peroxisome abundance and identified a phytochrome A-dependent pathway responsible for the proliferation of peroxisomes during dark-to-light transition in Arabidopsis seedlings. Light induces peroxisome proliferation at least in part through upregulating the PEX11b gene, which encodes a peroxisomal membrane protein that mediates the early stages of peroxisome multiplication. Activation of PEX11b requires the far-red light receptor phyA, as well as the bZIP transcription factor HYH, which binds directly to the promoter of PEX11b. We conclude that during photomorphogenesis, both the import of leaf-peroxisome enzymes from the cytosol and the induction of peroxisome proliferation take place to prepare seedlings for photosynthesis and photorespiration. In addition to light, other plant peroxisome proliferators may also exert their functions by targeting members of the PEX11 gene family for transcriptional activation. PMID:19704562

  11. Proteomic analysis reveals that the Rab GTPase RabE1c is involved in the degradation of the peroxisomal protein receptor PEX7 (peroxin 7).

    PubMed

    Cui, Songkui; Fukao, Yoichiro; Mano, Shoji; Yamada, Kenji; Hayashi, Makoto; Nishimura, Mikio

    2013-02-22

    The biogenesis of peroxisomes is mediated by peroxins (PEXs). PEX7 is a cytosolic receptor that imports peroxisomal targeting signal type 2 (PTS2)-containing proteins. Although PEX7 is important for protein transport, the mechanisms that mediate its function are unknown. In this study, we performed proteomic analysis to identify PEX7-binding proteins using transgenic Arabidopsis expressing green fluorescent protein (GFP)-tagged PEX7. Our analysis identified RabE1c, a small GTPase, as a PEX7 binding partner. In vivo analysis revealed that GTP-bound RabE1c binds to PEX7 and that a subset of RabE1c localizes to peroxisomes and interacts with PEX7 on the peroxisome membrane. Unlike endogenous PEX7, which is predominantly localized to the cytosol, GFP-PEX7 accumulates abnormally on the peroxisomal membrane and induces degradation of endogenous PEX7, concomitant with a reduction in import of PTS2-containing proteins and decreased peroxisomal β-oxidation activity. Thus, GFP-PEX7 on the peroxisomal membrane exerts a dominant negative effect. Mutation of RabE1c restored endogenous PEX7 protein expression and import of PTS2-containing proteins as well as peroxisomal β-oxidation activity. Treatment with proteasome inhibitors also restored endogenous PEX7 protein levels in GFP-PEX7-expressing seedlings. Based on these findings, we conclude that RabE1c binds PEX7 and facilitates PEX7 degradation in the presence of immobile GFP-PEX7 accumulated at the membrane. PMID:23297417

  12. PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR? (PPAR?) AGONISTS DIFFERENTIALLY REGULATE INHIBITOR OF DNA BINDING (ID2) EXPRESSION IN RODENTS AND HUMAN CELLS

    EPA Science Inventory

    Abstract Inhibitor of DNA binding (Id2) is a member of the helix-loop-helix (HLH) transcription factor family whose members play important roles in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones,...

  13. PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORα (PPARα) AGONISTS DIFFERENTIALLY REGULATE INHIBITOR OF DNA BINDING (ID2) EXPRESSION IN RODENTS AND HUMAN CELLS

    EPA Science Inventory

    Abstract Inhibitor of DNA binding (Id2) is a member of the helix-loop-helix (HLH) transcription factor family whose members play important roles in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones,...

  14. Peroxisome proliferator-activated receptor {alpha}-independent peroxisome proliferation

    SciTech Connect

    Zhang Xiuguo; Tanaka, Naoki . E-mail: naopi@hsp.md.shinshu-u.ac.jp; Nakajima, Takero; Kamijo, Yuji; Gonzalez, Frank J.; Aoyama, Toshifumi

    2006-08-11

    Hepatic peroxisome proliferation, increases in the numerical and volume density of peroxisomes, is believed to be closely related to peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}) activation; however, it remains unknown whether peroxisome proliferation depends absolutely on this activation. To verify occurrence of PPAR{alpha}-independent peroxisome proliferation, fenofibrate treatment was used, which was expected to significantly enhance PPAR{alpha} dependence in the assay system. Surprisingly, a novel type of PPAR{alpha}-independent peroxisome proliferation and enlargement was uncovered in PPAR{alpha}-null mice. The increased expression of dynamin-like protein 1, but not peroxisome biogenesis factor 11{alpha}, might be associated with the PPAR{alpha}-independent peroxisome proliferation at least in part.

  15. Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) agonist, independently of PPAR{gamma} in human glioma cells

    SciTech Connect

    Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung; Kim, Hye Jin; Yang, Jin Mo; Ryu, Somi; Noh, Yoo Hun; Lee, Soo Hyun; Son, Meong Hi; Jung, Hye Lim; Yoo, Keon Hee; Koo, Hong Hoe; Sung, Ki Woong

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Greater than 30 {mu}M ciglitazone induces cell death in glioma cells. Black-Right-Pointing-Pointer Cell death by ciglitazone is independent of PPAR{gamma} in glioma cells. Black-Right-Pointing-Pointer CGZ induces cell death by the loss of MMP via decreased Akt. -- Abstract: Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPAR{gamma} in CGZ-induced cell death was examined. At concentrations of greater than 30 {mu}M, CGZ, a synthetic PPAR{gamma} agonist, activated caspase-3 and induced apoptosis in T98G cells. Treatment of T98G cells with less than 30 {mu}M CGZ effectively induced cell death after pretreatment with 30 {mu}M of the PPAR{gamma} antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPAR{gamma} was down-regulated cells by siRNA, lower concentrations of CGZ (<30 {mu}M) were sufficient to induce cell death, although higher concentrations of CGZ ( Greater-Than-Or-Slanted-Equal-To 30 {mu}M) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPAR{gamma}. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPAR{gamma} in glioma cells, by down-regulating Akt activity and inducing MMP collapse.

  16. Neuronal inactivation of peroxisome proliferator-activated receptor ? coactivator 1? (PGC-1?) protects mice from diet-induced obesity and leads to degenerative lesions.

    PubMed

    Ma, Di; Li, Siming; Lucas, Elizabeth K; Cowell, Rita M; Lin, Jiandie D

    2010-12-10

    Peroxisome proliferator-activated receptor ? coactivator 1? (PGC-1?) is a transcriptional coactivator that regulates diverse aspects of energy metabolism in peripheral tissues. Mice deficient in PGC-1? have elevated metabolic rate and are resistant to diet-induced obesity. However, it remains unknown whether this alteration in energy balance is due to the action of PGC-1? in peripheral tissues or the central nervous system. In this study, we generated neuronal PGC-1? knock-out mice (B?KO) using calcium/calmodulin-dependent protein kinase II? (CaMKII?)-Cre to address its role in the regulation of energy balance and neuronal function. Unlike whole body PGC-1? null mice, B?KO mice have normal adaptive metabolic response to starvation and cold exposure in peripheral tissues. In contrast, B?KO mice are hypermetabolic, and similar to whole body PGC-1? null mice, are also resistant to diet-induced obesity, resulting in significantly improved metabolic profiles. Neuronal inactivation of PGC-1? leads to striatal lesions that are reminiscent of neurodegeneration in whole body PGC-1? null brain and impairs nutritional regulation of hypothalamic expression of genes that regulate systemic energy balance. Together, these studies have demonstrated a physiological role for neuronal PGC-1? in the control of energy balance. Our results also implicate CaMKII?-positive neurons as an important part of the neural circuitry that governs energy expenditure in vivo. PMID:20947495

  17. The environmental obesogen tributyltin chloride acts via peroxisome proliferator activated receptor gamma to induce adipogenesis in murine 3T3-L1 preadipocytes

    PubMed Central

    Li, Xia; Ycaza, John; Blumberg, Bruce

    2012-01-01

    Obesogens are chemicals that predispose exposed individuals to weight gain and obesity by increasing the number of fat cells, storage of fats into existing cells, altering metabolic rates, or disturbing the regulation of appetite and satiety. Tributyltin exposure causes differentiation of multipotent stromal stem cells (MSCs) into adipocytes; prenatal TBT exposure leads to epigenetic changes in the stem cell compartment that favor the production of adipocytes at the expense of bone, in vivo. While it is known that TBT acts through peroxisome proliferator activated receptor gamma to induce adipogenesis in MSCs, the data in 3T3-L1 preadipocytes are controversial. Here we show that TBT can activate the RXR-PPARγ heterodimer even in the presence of the PPARγ antagonist GW9662. We found that GW9662 has a ten-fold shorter half-life in cell culture than do PPARγ activators such as rosiglitazone (ROSI), accounting for previous observations that GW9662 did not inhibit TBT-mediated adipogenesis. When the culture conditions are adjusted to compensate for the short half-life of GW-9662, we found that TBT induces adipogenesis, triglyceride storage and the expression of adipogenic marker genes in 3T3-L1 cells in a PPARγ-dependent manner. Our results are broadly applicable to the study of obesogen action and indicate that ligand stability is an important consideration in the design and interpretation of adipogenesis assays. PMID:21397693

  18. Peroxisome proliferator activated receptor-? agonists protect oligodendrocyte progenitors against tumor necrosis factor-alpha-induced damage: Effects on mitochondrial functions and differentiation.

    PubMed

    De Nuccio, C; Bernardo, A; Cruciani, C; De Simone, R; Visentin, S; Minghetti, L

    2015-09-01

    The activation of the nuclear receptor peroxisome proliferator-activated receptor-? (PPAR-?) is known to exert anti-inflammatory and neuroprotective effects and PPAR-? agonists are considered potential therapeutic agents in brain diseases including those affecting myelin. In demyelinating diseases such as multiple sclerosis (MS), inflammation is one of the causes of myelin and axonal damage. Oligodendrocyte (OL) differentiation is highly dependent on mitochondria, which are major targets of inflammatory insult. Here we show that PPAR-? agonists protect OL progenitors against the maturational arrest induced by the inflammatory cytokine TNF-? by affecting mitochondrial functions. We demonstrate that the inhibition of OL differentiation by TNF-? is associated with i) increased mitochondrial superoxide production; ii) decreased mitochondrial membrane potential (mMP); and iii) decreased ADP-induced Ca(2+) oscillations, which we previously showed to be dependent on efficient mitochondria. The TNF-? effects were comparable to those of the mitochondrial toxin rotenone, further suggesting that TNF-? damage is mediated by mitochondrial function impairment. PPAR-? agonists protected OL progenitors against the inhibitory activities of both TNF-? and rotenone on mMP, mitochondrial ROS production, Ca(2+) oscillations and OL differentiation. Finally, the PPAR-? agonist pioglitazone increased the expression of PGC-1? (a mitochondrial biogenesis master regulator), UCP2 (a mitochondrial protein known to reduce ROS production), and cytochrome oxidase subunit COX1. These findings confirm the central role of mitochondria in OL differentiation and point to mitochondria as major targets of PPAR-? agonist protection against TNF-? damage. PMID:26210873

  19. Clofibric acid induces hepatic CYP 2B1/2 via constitutive androstane receptor not via peroxisome proliferator activated receptor alpha in rat.

    PubMed

    Ibrahim, Zein Shaban; Ahmed, Mohamed Mohamed; El-Shazly, Samir Ahmed; Ishizuka, Mayumi; Fujita, Shoichi

    2014-01-01

    Peroxisome proliferator activated receptor ? (PPAR?) ligands, fibrates used to control hyperlipidemia. We demonstrated CYP2B induction by clofibric acid (CFA) however, the mechanism was not clear. In this study, HepG2 cells transfected with expression plasmid of mouse constitutive androstane receptor (CAR) or PPAR? were treated with CFA, phenobarbital (PB) or TCPOBOP. Luciferase assays showed that CFA increased CYP2B1 transcription to the same level as PB, or TCPOBOP in HepG2 transfected with mouse CAR But failed to induce it in PPAR? transfected cells. CYP2B expressions were increased with PB or CFA in Wistar female rats (having normal levels of CAR) but not in Wistar Kyoto female rats (having low levels of CAR). The induction of CYP2B by PB or CFA was comparable to nuclear CAR levels. CAR nuclear translocation was induced by CFA in both rat strains. This indicates that fibrates can activate CAR and that fibrates-insulin sensitization effect may occur through CAR, while hypolipidemic effect may operate through PPAR?. PMID:25052003

  20. [Adverse skin reactions induced by BRAF inhibitors: a systematic review].

    PubMed

    Sibaud, V; Lamant, L; Maisongrosse, V; Delord, J-P

    2013-01-01

    Recent developments and therapeutic use of selective BRAF inhibitors (e.g. dabrafenib and vemurafenib) have significantly improved overall survival and disease-free survival of patients with BRAF V600 mutation-positive metastatic melanoma. Despite their survival benefits, small-molecule inhibitors of BRAF are associated with significant and sometimes severe treatment-related dermatological toxicity. The most common adverse skin reactions include photosensitivity, induced malignant lesions of the skin such as keratoacanthomas, squamous cell carcinoma and new primary melanomas, as well as keratinocyte proliferation and differentiation dysfunctions that can manifest as skin papillomas, hand-foot skin reaction, keratosis pilaris-like rash, acantholytic dyskeratosis and cysts of the milia type. In this article, we describe the clinical and histological features of the cutaneous manifestations induced by vemurafenib and dabrafenib on the basis of our clinical experience and a literature review. The crucial role of dermatologists in patient management is also highlighted. PMID:24034635

  1. Potentially lethal ACE-inhibitor-induced angioedema in a child

    PubMed Central

    Bukhari, Esraa; Safdar, Osama Y; Shalaby, Mohammed; AlSharif, Shafiqa MJ; Alsufiany, Khoulod; Kari, Jameela A

    2015-01-01

    Key Clinical Message We report a case of a 9-year-old female with known end-stage kidney disease who presented with sudden onset tongue swelling. A diagnosis of angiotensin-converting enzyme inhibitor-induced angioedema related to bradykinin accumulation was made. Her symptoms resolved shortly after discontinuation of captopril. Early diagnosis can save patients from severe upper airway obstruction. PMID:26185642

  2. Dietary ?-conglycinin prevents fatty liver induced by a high-fat diet by a decrease in peroxisome proliferator-activated receptor ?2 protein.

    PubMed

    Yamazaki, Tomomi; Kishimoto, Kyoko; Miura, Shinji; Ezaki, Osamu

    2012-02-01

    Diets high in sucrose/fructose or fat can result in hepatic steatosis (fatty liver). Mice fed a high-fat diet, especially that of saturated-fat-rich oil, develop fatty liver with an increase in peroxisome proliferator-activated receptor (PPAR) ?2 protein in liver. The fatty liver induced by a high-fat diet is improved by knockdown of liver PPAR?2. In this study, we investigated whether ?-conglycinin (a major protein of soy protein) could reduce PPAR?2 protein and prevent high-fat-diet-induced fatty liver in ddY mice. Mice were fed a high-starch diet (70 energy% [en%] starch) plus 20% (wt/wt) sucrose in their drinking water or a high-safflower-oil diet (60 en%) or a high-butter diet (60 en%) for 11 weeks, by which fatty liver is developed. As a control, mice were fed a high-starch diet with drinking water. Either ?-conglycinin or casein (control) was given as dietary protein. ?-Conglycinin supplementation completely prevented fatty liver induced by each type of diet, along with a reduction in adipose tissue weight. ?-Conglycinin decreased sterol regulatory element-binding protein (SREBP)-1c and carbohydrate response element-binding protein (ChREBP) messenger RNAs (mRNAs) in sucrose-supplemented mice, whereas it decreased PPAR?2 mRNA (and its target genes CD36 and FSP27), but did not decrease SREBP-1c and ChREBP mRNAs, in mice fed a high-fat diet. ?-Conglycinin decreased PPAR?2 protein and liver triglyceride (TG) concentration in a dose-dependent manner in mice fed a high-butter diet; a significant decrease in liver TG concentration was observed at a concentration of 15 en%. In conclusion, ?-conglycinin effectively prevents fatty liver induced by a high-fat diet through a decrease in liver PPAR?2 protein. PMID:21447441

  3. Bisphenol A Diglycidyl Ether Induces Adipogenic Differentiation of Multipotent Stromal Stem Cells through a Peroxisome Proliferator–Activated Receptor Gamma-Independent Mechanism

    PubMed Central

    Chamorro-García, Raquel; Kirchner, Séverine; Li, Xia; Janesick, Amanda; Casey, Stephanie C.; Chow, Connie

    2012-01-01

    Background: Bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE), used in manufacturing coatings and resins, leach from packaging materials into food. Numerous studies suggested that BPA and BADGE may have adverse effects on human health, including the possibility that exposure to such chemicals can be superimposed on traditional risk factors to initiate or exacerbate the development of obesity. BPA is a suspected obesogen, whereas BADGE, described as a peroxisome proliferator–activated receptor gamma (PPARγ) antagonist, could reduce weight gain. Objectives: We sought to test the adipogenic effects of BADGE in a biologically relevant cell culture model. Methods: We used multipotent mesenchymal stromal stem cells (MSCs) to study the adipogenic capacity of BADGE and BPA and evaluated their effects on adipogenesis, osteogenesis, gene expression, and nuclear receptor activation. Discussion: BADGE induced adipogenesis in human and mouse MSCs, as well as in mouse 3T3-L1 preadipocytes. In contrast, BPA failed to promote adipogenesis in MSCs, but induced adipogenesis in 3T3-L1 cells. BADGE exposure elicited an adipogenic gene expression profile, and its ability to induce adipogenesis and the expression of adipogenic genes was not blocked by known PPARγ antagonists. Neither BADGE nor BPA activated or antagonized retinoid “X” receptor (RXR) or PPARγ in transient transfection assays. Conclusions: BADGE can induce adipogenic differentiation in both MSCs and in preadipocytes at low nanomolar concentrations comparable to those that have been observed in limited human biomonitoring. BADGE probably acts through a mechanism that is downstream of, or parallel to, PPARγ. PMID:22763116

  4. Peroxisome proliferator-activated receptor gamma (PPAR?) regulates thrombospondin-1 and Nox4 expression in hypoxia-induced human pulmonary artery smooth muscle cell proliferation

    PubMed Central

    Green, David E.; Kang, Bum-Yong; Murphy, Tamara C.; Hart, C. Micheal

    2012-01-01

    Transforming growth factor-?1 (TGF- ?1) and thrombospondin-1 (TSP-1) are hypoxia-responsive mitogens that promote vascular smooth muscle cell (SMC) proliferation, a critical event in the pathogenesis of pulmonary hypertension (PH). We previously demonstrated that hypoxia-induced human pulmonary artery smooth muscle (HPASMC) cell proliferation and expression of the NADPH oxidase subunit, Nox4, were attenuated by the peroxisome proliferator-activated receptor ? (PPAR?) agonist, rosiglitazone. The current study examines the hypothesis that rosiglitazone regulates Nox4 expression and HPASMC proliferation by attenuating TSP-1 signaling. Selected HPASMC were exposed to normoxic or hypoxic (1% O2) environments or TSP-1 (0-1 ?g/ ml) for 72 hours administration of rosiglitazone (10 ?M). Cellular proliferation, Nox4, TSP-1, and TGF-?1 expression and reactive oxygen species generation were measured. Mice exposed to hypoxia (10% O2) for three weeks were treated with rosiglitazone (10 mg/kg/day) for the final 10 days, and lung TSP-1 expression was examined. Hypoxia increased TSP-1 and TGF-?1 expression and HPASMC proliferation, and neutralizing antibodies to TSP-1 or TGF-?1 attenuated proliferation. Rosiglitazone attenuated hypoxia-induced HPASMC proliferation and increases in mouse lung and HPASMC TSP-1 expression, but failed to reduce increases in TGF-?1 expression or Nox4 expression and activity caused by direct TSP-1 stimulation. Transfecting HPASMC with siRNA to Nox4 attenuated hypoxia- or TSP-1-stimulated HPASMC proliferation. These findings provide novel evidence that TSP-1-mediated Nox4 expression plays a critical role in hypoxia-induced HPASMC proliferation. PPAR? activation with exogenous ligands attenuates TSP-1 expression to reduce Nox4 expression. These results clarify mechanisms of hypoxia-induced SMC proliferation and suggest additional pathways by which PPAR? agonists may regulate critical steps in the pathobiology of PH. PMID:23372933

  5. Prostaglandin synthesis inhibitors block alcohol-induced fetal hypoplasia.

    PubMed

    Pennington, S; Allen, Z; Runion, J; Farmer, P; Rowland, L; Kalmus, G

    1985-01-01

    Alcohol-induced growth retardation is a fetal effect consistently associated with maternal ethanol consumption. In humans, those infants whose mothers consume even a limited amount of ethanol during pregnancy have a significant incidence of growth inhibition. The molecular mechanism responsible for this growth deficiency is unknown, and prevention depends on maternal abstinence during pregnancy. The data reported here suggest that ethanol-mediated increases in tissue prostaglandin (PG) E levels (PGE1 plus PGE2) are correlated with the growth retardation. Further, simultaneous administration of PG synthesis inhibitors with the alcohol blocks the rise in tissue PG levels and protects against the alcohol-induced hypoplasia. PMID:3904508

  6. Novel EGFR inhibitors attenuate cardiac hypertrophy induced by angiotensin II.

    PubMed

    Peng, Kesong; Tian, Xinqiao; Qian, Yuanyuan; Skibba, Melissa; Zou, Chunpeng; Liu, Zhiguo; Wang, Jingying; Xu, Zheng; Li, Xiaokun; Liang, Guang

    2016-03-01

    Cardiac hypertrophy is an important risk factor for heart failure. Epidermal growth factor receptor (EGFR) has been found to play a role in the pathogenesis of various cardiovascular diseases. The aim of this current study was to examine the role of EGFR in angiotensin II (Ang II)-induced cardiac hypertrophy and identify the underlying molecular mechanisms. In this study, we observed that both Ang II and EGF could increase the phospohorylation of EGFR and protein kinase B (AKT)/extracellular signal-regulated kinase (ERK), and then induce cell hypertrophy in H9c2 cells. Both pharmacological inhibitors and genetic silencing significantly reduced Ang II-induced EGFR signalling pathway activation, hypertrophic marker overexpression, and cell hypertrophy. In addition, our results showed that Ang II-induced EGFR activation is mediated by c-Src phosphorylation. In vivo, Ang II treatment significantly led to cardiac remodelling including cardiac hypertrophy, disorganization and fibrosis, accompanied by the activation of EGFR signalling pathway in the heart tissues, while all these molecular and pathological alterations were attenuated by the oral administration with EGFR inhibitors. In conclusion, the c-Src-dependent EGFR activation may play an important role in Ang II-induced cardiac hypertrophy, and inhibition of EGFR by specific molecules may be an effective strategy for the treatment of Ang II-associated cardiac diseases. PMID:26762600

  7. Skeletal muscle Heat shock protein 60 increases after endurance training and induces peroxisome proliferator-activated receptor gamma coactivator 1 α1 expression

    PubMed Central

    Barone, Rosario; Macaluso, Filippo; Sangiorgi, Claudia; Campanella, Claudia; Marino Gammazza, Antonella; Moresi, Viviana; Coletti, Dario; Conway de Macario, Everly; Macario, Alberto JL; Cappello, Francesco; Adamo, Sergio; Farina, Felicia; Zummo, Giovanni; Di Felice, Valentina

    2016-01-01

    Heat shock protein 60 (Hsp60) is a chaperone localizing in skeletal muscle mitochondria, whose role is poorly understood. In the present study, the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) were evaluated in mice after completing a 6-week endurance training program. The correlation between Hsp60 levels and the expression of four isoforms of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) were investigated only in soleus. Short-term overexpression of hsp60, achieved by in vitro plasmid transfection, was then performed to determine whether this chaperone could have a role in the activation of the expression levels of PGC1α isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC1α increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC1 1α, suggesting a correlation between Hsp60 overexpression and PGC1 1 α activation. PMID:26812922

  8. Over-expression of C/EBP-{alpha} induces apoptosis in cultured rat hepatic stellate cells depending on p53 and peroxisome proliferator-activated receptor-{gamma}

    SciTech Connect

    Wang Xueqing; Huang Guangcun; Mei Shuang; Qian Jin; Ji Juling; Zhang Jinsheng

    2009-03-06

    Hepatic stellate cells (HSCs) play a key role in the pathogenesis of hepatic fibrosis. In our previous studies, CCAAT enhancer binding protein-{alpha} (C/EBP-{alpha}) has been shown to be involved in the activation of HSCs and to have a repression effect on hepatic fibrosis in vivo. However, the mechanisms are largely unknown. In this study, we show that the infection of adenovirus vector expressing C/EBP-{alpha} gene (Ad-C/EBP-{alpha}) could induce HSCs apoptosis in a dose- and time-dependent manner by Annexin V/PI staining, caspase-3 activation assay, and flow cytometry. Also, over-expression of C/EBP-{alpha} resulted in the up-regulation of peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) and P53, while P53 expression was regulated by PPAR-{gamma}. In addition, Fas, FasL, DR4, DR5, and TRAIL were studied. The results indicated that the death receptor pathway was mainly involved and regulated by PPAR-{gamma} and p53 in the process of apoptosis triggered by C/EBP-{alpha} in HSCs.

  9. Pharmacological activation of peroxisome proliferator-activated receptor ? improves insulin resistance and hepatic steatosis in high fat diet-induced diabetic mice.

    PubMed

    Wu, H-T; Chen, C-T; Cheng, K-C; Li, Y-X; Yeh, C-H; Cheng, J-T

    2011-08-01

    The mechanisms regarding hepatic steatosis related to hepatic insulin resistance have been well documented. However, the agents for treatment of hepatic steatosis and insulin resistance remain poorly developed. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that are responsible for the regulation of glucose and/or lipid metabolism. There are 3 distinct isoforms of PPARs family: PPAR?, PPAR?, and PPAR?. Both PPAR? and PPAR? agonists are widely used in clinic for the treatment of hyperlipidemia and hyperglycemia. However, the therapeutic efficacy of PPAR? agonists for diabetic disorders remains obscure. In the present study, we used L-165041?as PPAR? agonist to treat the high fat diet (HFD) fed mice. Administration of L-165041 improved the hepatic steatosis and increased the insulin sensitivity in HFD-mice. In addition to the histological identification of hepatic steatosis, the improvement of insulin sensitivity was characterized by the enhanced insulin signals and the increase of hepatic glycogen content. This is the first report showing that pharmacological activation of PPAR? improves insulin resistance in diet-induced diabetic mice. Thus, we suggest that pharmacological activation of PPAR? may be a new strategy for the treatment of diabetic patients with hepatic steatosis. PMID:21725906

  10. Antagonist of peroxisome proliferator-activated receptor {gamma} induces cerebellar amyloid-{beta} levels and motor dysfunction in APP/PS1 transgenic mice

    SciTech Connect

    Du, Jing; Sun, Bing; Chen, Kui; Fan, Li; Cardiovascular Research, Starr Academic Center, Providence Heart and Vascular Institute, Portland, OR 97225 ; Wang, Zhao

    2009-07-03

    Recent evidences show that peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) is involved in the modulation of the amyloid-{beta} (A{beta}) cascade causing Alzheimer's disease (AD) and treatment with PPAR{gamma} agonists protects against AD pathology. However, the function of PPAR{gamma} steady-state activity in A{beta} cascade and AD pathology remains unclear. In this study, an antagonist of PPAR{gamma}, GW9662, was injected into the fourth ventricle of APP/PS1 transgenic mice to inhibit PPAR{gamma} activity in cerebellum. The results show that inhibition of PPAR{gamma} significantly induced A{beta} levels in cerebellum and caused cerebellar motor dysfunction in APP/PS1 transgenic mice. Moreover, GW9662 treatment markedly decreased the cerebellar levels of insulin-degrading enzyme (IDE), which is responsible for the cellular degradation of A{beta}. Since cerebellum is spared from significant A{beta} accumulation and neurotoxicity in AD patients and animal models, these findings suggest a crucial role of PPAR{gamma} steady-state activity in protection of cerebellum against AD pathology.

  11. Skeletal muscle Heat shock protein 60 increases after endurance training and induces peroxisome proliferator-activated receptor gamma coactivator 1 ?1 expression.

    PubMed

    Barone, Rosario; Macaluso, Filippo; Sangiorgi, Claudia; Campanella, Claudia; Marino Gammazza, Antonella; Moresi, Viviana; Coletti, Dario; Conway de Macario, Everly; Macario, Alberto Jl; Cappello, Francesco; Adamo, Sergio; Farina, Felicia; Zummo, Giovanni; Di Felice, Valentina

    2016-01-01

    Heat shock protein 60 (Hsp60) is a chaperone localizing in skeletal muscle mitochondria, whose role is poorly understood. In the present study, the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) were evaluated in mice after completing a 6-week endurance training program. The correlation between Hsp60 levels and the expression of four isoforms of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1?) were investigated only in soleus. Short-term overexpression of hsp60, achieved by in vitro plasmid transfection, was then performed to determine whether this chaperone could have a role in the activation of the expression levels of PGC1? isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC1? increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC1 1?, suggesting a correlation between Hsp60 overexpression and PGC1 1 ? activation. PMID:26812922

  12. Multiple paths to peroxisomes: Mechanism of peroxisome maintenance in mammals.

    PubMed

    Hua, Rong; Kim, Peter K

    2016-05-01

    Peroxisomes are dynamic organelles that can adjust their size and number in response to cellular demand and environmental stimuli. They can propagate from pre-existing peroxisomes through growth and division, as well as de novo from the endoplasmic reticulum (ER). However, to what extend that these two distinct peroxisome biogenesis pathways are involved in maintaining peroxisome numbers in cycling cells is unclear. Recent studies in yeast suggest that the ER plays a direct role in the maintenance of peroxisomes. However, the role of the ER in mammalian system is under debate. In this review, we outline the recent progress in understanding the biogenesis of mammalian peroxisomes. We herein discuss some of the discrepancies in the literature and the outstanding questions in the field. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26408931

  13. Peroxisome proliferator-activated receptor-? ligands induce heme oxygenase-1 in lung fibroblasts by a PPAR?-independent, glutathione-dependent mechanism

    PubMed Central

    Ferguson, Heather E.; Thatcher, Thomas H.; Olsen, Keith C.; Garcia-Bates, Tatiana M.; Baglole, Carolyn J.; Kottmann, R. M.; Strong, Emily R.; Phipps, Richard P.

    2009-01-01

    Oxidative stress plays an important role in the pathogenesis of pulmonary fibrosis. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme, and overexpression of HO-1 significantly decreases lung inflammation and fibrosis in animal models. Peroxisome proliferator-activated receptor-? (PPAR?) is a transcription factor that regulates adipogenesis, insulin sensitization, and inflammation. We report here that the PPAR? ligands 15d-PGJ2 and 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), which have potent antifibrotic effects in vitro, also strongly induce HO-1 expression in primary human lung fibroblasts. Pharmacological and genetic approaches are used to demonstrate that induction of HO-1 is PPAR? independent. Upregulation of HO-1 coincides with decreased intracellular glutathione (GSH) levels and can be inhibited by N-acetyl cysteine (NAC), a thiol antioxidant and GSH precursor. Upregulation of HO-1 is not inhibited by Trolox, a non-thiol antioxidant, and does not involve the transcription factors AP-1 or Nrf2. CDDO and 15d-PGJ2 contain an ?/? unsaturated ketone that acts as an electrophilic center that can form covalent bonds with free reduced thiols. Rosiglitazone, a PPAR? ligand that lacks an electrophilic center, does not induce HO-1. These data suggest that in human lung fibroblasts, 15d-PGJ2 and CDDO induce HO-1 via a GSH-dependent mechanism involving the formation of covalent bonds between 15d-PGJ2 or CDDO and GSH. Inhibiting HO-1 upregulation with NAC has only a small effect on the antifibrotic properties of 15d-PGJ2 and CDDO in vitro. These results suggest that CDDO and similar electrophilic PPAR? ligands may have great clinical potential as antifibrotic agents, not only through direct effects on fibroblast differentiation and function, but indirectly by bolstering antioxidant defenses. PMID:19734319

  14. Peroxisome proliferator-activated receptor-gamma ligands induce heme oxygenase-1 in lung fibroblasts by a PPARgamma-independent, glutathione-dependent mechanism.

    PubMed

    Ferguson, Heather E; Thatcher, Thomas H; Olsen, Keith C; Garcia-Bates, Tatiana M; Baglole, Carolyn J; Kottmann, R M; Strong, Emily R; Phipps, Richard P; Sime, Patricia J

    2009-11-01

    Oxidative stress plays an important role in the pathogenesis of pulmonary fibrosis. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme, and overexpression of HO-1 significantly decreases lung inflammation and fibrosis in animal models. Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a transcription factor that regulates adipogenesis, insulin sensitization, and inflammation. We report here that the PPARgamma ligands 15d-PGJ2 and 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), which have potent antifibrotic effects in vitro, also strongly induce HO-1 expression in primary human lung fibroblasts. Pharmacological and genetic approaches are used to demonstrate that induction of HO-1 is PPARgamma independent. Upregulation of HO-1 coincides with decreased intracellular glutathione (GSH) levels and can be inhibited by N-acetyl cysteine (NAC), a thiol antioxidant and GSH precursor. Upregulation of HO-1 is not inhibited by Trolox, a non-thiol antioxidant, and does not involve the transcription factors AP-1 or Nrf2. CDDO and 15d-PGJ2 contain an alpha/beta unsaturated ketone that acts as an electrophilic center that can form covalent bonds with free reduced thiols. Rosiglitazone, a PPARgamma ligand that lacks an electrophilic center, does not induce HO-1. These data suggest that in human lung fibroblasts, 15d-PGJ2 and CDDO induce HO-1 via a GSH-dependent mechanism involving the formation of covalent bonds between 15d-PGJ2 or CDDO and GSH. Inhibiting HO-1 upregulation with NAC has only a small effect on the antifibrotic properties of 15d-PGJ2 and CDDO in vitro. These results suggest that CDDO and similar electrophilic PPARgamma ligands may have great clinical potential as antifibrotic agents, not only through direct effects on fibroblast differentiation and function, but indirectly by bolstering antioxidant defenses. PMID:19734319

  15. Arginase inhibitor attenuates pulmonary artery hypertension induced by hypoxia.

    PubMed

    Chu, YanBiao; XiangLi, XiaoYing; Niu, Hu; Wang, HongChao; Jia, PingDong; Gong, WenBin; Wu, DaWei; Qin, WeiDong; Xing, ChunYan

    2016-01-01

    Hypoxia-induced pulmonary arterial hypertension (HPAH) is a refractory disease characterized by increased proliferation of pulmonary vascular smooth cells and progressive pulmonary vascular remodeling. The level of nitric oxide (NO), a potential therapeutic vasodilator, is low in PAH patients. L-arginine can be converted to either beneficial NO by nitric oxide synthases or to harmful urea by arginase. In the present study, we aimed to investigate whether an arginase inhibitor, S-(2-boronoethyl)-L-cysteine ameliorates HPAH in vivo and vitro. In a HPAH mouse model, we assessed right ventricle systolic pressure (RVSP) by an invasive method, and found that RSVP was elevated under hypoxia, but was attenuated upon arginase inhibition. Human pulmonary artery smooth muscle cells (HPASMCs) were cultured under hypoxic conditions, and their proliferative capacity was determined by cell counting and flow cytometry. The levels of cyclin D1, p27, p-Akt, and p-ERK were detected by RT-PCR or Western blot analysis. Compared to hypoxia group, arginase inhibitor inhibited HPASMCs proliferation and reduced the levels of cyclin D1, p-Akt, p-ERK, while increasing p27 level. Moreover, in mouse models, compared to control group, hypoxia increased cyclin D1 expression but reduced p27 expression, while arginase inhibitor reversed the effects of hypoxia. Taken together, these results suggest that arginase plays an important role in increased proliferation of HPASMCs induced by hypoxia and it is a potential therapeutic target for the treatment of pulmonary hypertensive disorders. PMID:26608181

  16. Evaluating Chemical CDK Inhibitors as Cell Death Inducers.

    PubMed

    Hirai, Hiroshi; Nakatsuru, Yoko

    2016-01-01

    The cell cycle of eukaryotic cells is regulated by a family of protein kinases called cyclin-dependent kinases (Cdks). We have reported the identification and biological characterization of a highly potent, small-molecule pan-Cdk inhibitor, which inhibited Cdk1, 2, 4, 5, 6, and 9 with equal potency in the nM range. This compound inhibited multiple events in the cell cycle and induced cell death in human cancer cell lines as well as in peripheral blood or purified resting lymphocytes ex vivo. We describe the materials and methods to determine antitumor efficacy in vivo xenograft models. Pharmacodynamic marker assays that have been performed using tumors and normal tissues are explained. Moreover, we briefly describe methods for determining the effects of chemical Cdk inhibitors on peripheral blood cells or lymphocytes ex vivo. PMID:26231716

  17. Induction of hepatic peroxisome proliferation in nonrodent species, including primates.

    PubMed

    Reddy, J K; Lalwani, N D; Qureshi, S A; Reddy, M K; Moehle, C M

    1984-01-01

    It is well established that the administration to rodents of a variety of structurally diverse chemicals possessing hypotriglyceridemic properties results in hepatomegaly, the induction of hepatic peroxisome (microbody) proliferation, and the development of hepatocellular carcinomas. Studies have led to the hypothesis that persistent proliferation of peroxisomes serves as an endogenous initiator of neoplastic transformation in liver by increasing the intracellular production of H2O2 by the peroxisomal oxidase(s). The objective of the present study was to determine whether hepatic peroxisome proliferation can be induced in cats, chickens, pigeons, and two species of monkeys (rhesus and cynomolgus). The hypolipidemic drug ciprofibrate (2-[4-(2,2-dichloro-cylopropyl)phenoxyl]2-methylpropionic acid) induced peroxisome proliferation in the livers of cats (dose, greater than 40 mg/kg body weight for 4 weeks); chickens (dose greater than 25 mg/kg body weight for 4 weeks); pigeons (300 mg/kg body weight for 3 weeks), rhesus monkeys (50 to 200 mg/kg body weight for 7 weeks) and cynomolgus monkeys (400 mg/kg body weight for 4 weeks). In all five species examined in this study, a marked but variable increase in the activities of peroxisomal catalase, carnitine acetyltransferase, heat-labile enoyl-CoA hydratase, and the fatty acid beta-oxidation system was observed. These results suggest that peroxisome proliferation can be induced in the livers of several species and that it is a dose-dependent but not a species-specific phenomenon. PMID:6691413

  18. Transcription Factors Krppel-Like Factor 6 and Peroxisome Proliferator-Activated Receptor-? Mediate High Glucose-Induced Thioredoxin-Interacting Protein

    PubMed Central

    Qi, Weier; Chen, Xinming; Holian, John; Tan, Christina Y.R.; Kelly, Darren J.; Pollock, Carol A.

    2009-01-01

    We demonstrated recently that thioredoxin-interacting protein (Txnip) and the transcription factor Krppel-like factor 6 (KLF6) were up-regulated in both in vivo and in vitro models of diabetic nephropathy, thus promoting renal injury. Conversely, peroxisome proliferator-activated receptor-? (PPAR-?) agonists have been shown to be renoprotective. Hence, this study was undertaken to determine whether Txnip expression is regulated by the transcription factors KLF6 and PPAR-?. By using siRNAs and overexpressing constructs, the role of KLF6 and PPAR-? in Txnip transcriptional regulation was determined in human kidney proximal tubule cells and in streptozocin-induced diabetes mellitus in Sprague-Dawley rats, in vitro and in vivo models of diabetic nephropathy, respectively. KLF6 overexpression increased Txnip expression and promoter activity, which was inhibited by concurrent exposure to PPAR-? agonists. In contrast, reduced expression of KLF6 by siRNA or exposure to PPAR-? agonists attenuated high glucose-induced Txnip expression and promoter activity. KLF6-Txnip promoter binding was decreased in KLF6-silenced cells, whereas PPAR-? agonists increased PPAR-?-Txnip promoter binding. Indeed, silencing of KLF6 increased PPAR-? expression, suggesting endogenous regulation of PPAR-? expression by KLF6. Moreover, renal KLF6 and Txnip expression increased in rats with diabetes mellitus and was inhibited by PPAR-? agonist treatment; however, KLF6 expression did not change in HK-2 cells exposed to PPAR-? agonists. Hence, Txnip expression and promoter activity are mediated via divergent effects of KLF6 and PPAR-? transcriptional regulation. PMID:19808645

  19. Transcription factors Krppel-like factor 6 and peroxisome proliferator-activated receptor-{gamma} mediate high glucose-induced thioredoxin-interacting protein.

    PubMed

    Qi, Weier; Chen, Xinming; Holian, John; Tan, Christina Y R; Kelly, Darren J; Pollock, Carol A

    2009-11-01

    We demonstrated recently that thioredoxin-interacting protein (Txnip) and the transcription factor Krppel-like factor 6 (KLF6) were up-regulated in both in vivo and in vitro models of diabetic nephropathy, thus promoting renal injury. Conversely, peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have been shown to be renoprotective. Hence, this study was undertaken to determine whether Txnip expression is regulated by the transcription factors KLF6 and PPAR-gamma. By using siRNAs and overexpressing constructs, the role of KLF6 and PPAR-gamma in Txnip transcriptional regulation was determined in human kidney proximal tubule cells and in streptozocin-induced diabetes mellitus in Sprague-Dawley rats, in vitro and in vivo models of diabetic nephropathy, respectively. KLF6 overexpression increased Txnip expression and promoter activity, which was inhibited by concurrent exposure to PPAR-gamma agonists. In contrast, reduced expression of KLF6 by siRNA or exposure to PPAR-gamma agonists attenuated high glucose-induced Txnip expression and promoter activity. KLF6-Txnip promoter binding was decreased in KLF6-silenced cells, whereas PPAR-gamma agonists increased PPAR-gamma-Txnip promoter binding. Indeed, silencing of KLF6 increased PPAR-gamma expression, suggesting endogenous regulation of PPAR-gamma expression by KLF6. Moreover, renal KLF6 and Txnip expression increased in rats with diabetes mellitus and was inhibited by PPAR-gamma agonist treatment; however, KLF6 expression did not change in HK-2 cells exposed to PPAR-gamma agonists. Hence, Txnip expression and promoter activity are mediated via divergent effects of KLF6 and PPAR-gamma transcriptional regulation. PMID:19808645

  20. Rosiglitazone, a Peroxisome Proliferator-Activated Receptor (PPAR)-? Agonist, Attenuates Inflammation Via NF-?B Inhibition in Lipopolysaccharide-Induced Peritonitis.

    PubMed

    Zhang, Yun-Fang; Zou, Xun-Liang; Wu, Jun; Yu, Xue-Qing; Yang, Xiao

    2015-12-01

    We assessed the anti-inflammatory effect of peroxisome proliferator-activated receptor (PPAR)-? agonist, rosiglitazone, in a lipopolysaccharide (LPS)-induced peritonitis rat model. LPS was intraperitoneally injected into rats to establish peritonitis model. Male Sprague-Dawley (SD) rats were assigned to normal saline (the solvent of LPS), LPS, rosiglitazone plus LPS, and rosiglitazone alone. A simple peritoneal equilibrium test was performed with 20ml 4.25% peritoneal dialysis fluid. We measured the leukocyte count in dialysate and ultrafiltration volume. Peritoneal membrane histochemical staining was performed, and peritoneal thickness was assessed. CD40 and intercellular adhesion molecule-1 messenger RNA (ICAM-1 mRNA) levels in rat visceral peritoneum were detected by reverse transcription (RT)-PCR. IL-6 in rat peritoneal dialysis effluent was measured using enzyme-linked immunosorbent assay. The phosphorylation of NF-?B-p65 and I?B? was analyzed by Western blot. LPS administration resulted in increased peritoneal thickness and decreased ultrafiltration volume. Rosiglitazone pretreatment significantly decreased peritoneal thickness. In addition to CD40 and ICAM-1 mRNA expression, the IL-6, p-p65, and p-I?B? protein expressions were enhanced in LPS-administered animals. Rosiglitazone pretreatment significantly decreased ICAM-1 mRNA upregulation, secretion of IL-6 protein, and phosphorylation of NF-?B-p65 and I?B? without decreasing CD40 mRNA expression. Rosiglitazone has a protective effect in peritonitis, simultaneously decreasing NF-?B phosphorylation, suggesting that NF-?B signaling pathway mediated peritoneal inflammation induced by LPS. PPAR-? might be considered a potential therapeutic target against peritonitis. PMID:26047949

  1. The birth of yeast peroxisomes.

    PubMed

    Yuan, Wei; Veenhuis, Marten; van der Klei, Ida J

    2016-05-01

    This contribution describes the phenotypic differences of yeast peroxisome-deficient mutants (pex mutants). In some cases different phenotypes were reported for yeast mutants deleted in the same PEX gene. These differences are most likely related to the marker proteins and methods used to detect peroxisomal remnants. This is especially evident for pex3 and pex19 mutants, where the localization of receptor docking proteins (Pex13, Pex14) resulted in the identification of peroxisomal membrane remnants, which do not contain other peroxisomal membrane proteins, such as the ring proteins Pex2, Pex10 and Pex12. These structures in pex3 and pex19 cells are the template for peroxisome formation upon introduction of the missing gene. Taken together, these data suggest that in all yeast pex mutants analyzed so far peroxisomes are not formed de novo but use membrane remnant structures as a template for peroxisome formation upon reintroduction of the missing gene. The relevance of this model for peroxisomal membrane protein and lipid sorting to peroxisomes is discussed. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26367802

  2. No peroxisome is an island - Peroxisome contact sites.

    PubMed

    Shai, Nadav; Schuldiner, Maya; Zalckvar, Einat

    2016-05-01

    In order to optimize their multiple cellular functions, peroxisomes must collaborate and communicate with the surrounding organelles. A common way of communication between organelles is through physical membrane contact sites where membranes of two organelles are tethered, facilitating exchange of small molecules and intracellular signaling. In addition contact sites are important for controlling processes such as metabolism, organelle trafficking, inheritance and division. How peroxisomes rely on contact sites for their various cellular activities is only recently starting to be appreciated and explored and the extent of peroxisomal communication, their contact sites and their functions are less characterized. In this review we summarize the identified peroxisomal contact sites, their tethering complexes and their potential physiological roles. Additionally, we highlight some of the preliminary evidence that exists in the field for unexplored peroxisomal contact sites. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26384874

  3. Large-Scale Purification of Peroxisomes for Preparative Applications.

    PubMed

    Cramer, Jana; Effelsberg, Daniel; Girzalsky, Wolfgang; Erdmann, Ralf

    2015-09-01

    This protocol is designed for large-scale isolation of highly purified peroxisomes from Saccharomyces cerevisiae using two consecutive density gradient centrifugations. Instructions are provided for harvesting up to 60 g of oleic acid-induced yeast cells for the preparation of spheroplasts and generation of organellar pellets (OPs) enriched in peroxisomes and mitochondria. The OPs are loaded onto eight continuous 36%-68% (w/v) sucrose gradients. After centrifugation, the peak peroxisomal fractions are determined by measurement of catalase activity. These fractions are subsequently pooled and subjected to a second density gradient centrifugation using 20%-40% (w/v) Nycodenz. PMID:26330621

  4. Peroxisome Proliferator-activated Receptor α (PPARα) Induces PPARγ Coactivator 1α (PGC-1α) Gene Expression and Contributes to Thermogenic Activation of Brown Fat

    PubMed Central

    Hondares, Elayne; Rosell, Meritxell; Díaz-Delfín, Julieta; Olmos, Yolanda; Monsalve, Maria; Iglesias, Roser; Villarroya, Francesc; Giralt, Marta

    2011-01-01

    Peroxisome proliferator activated receptor α (PPARα) is a distinctive marker of the brown fat phenotype that has been proposed to coordinate the transcriptional activation of genes for lipid oxidation and for thermogenic uncoupling protein 1 in brown adipose tissue. Here, we investigated the involvement of PPARα in the transcriptional control of the PPARγ coactivator (PGC)-1α gene. Treatment with PPARα agonists induced PGC-1α mRNA expression in brown fat in vivo and in primary brown adipocytes. This enhancement of PGC-1α transcription was mediated by PPARα binding to a PPAR-responsive element in the distal PGC-1α gene promoter. PGC-1α gene expression was decreased in PPARα-null brown fat, both under basal conditions and in response to thermogenic activation. Moreover, PPARα- and cAMP-mediated pathways interacted to control PGC-1α transcription. PRDM16 (PRD1-BF1-RIZ1 homologous domain-containing 16) promoted PPARα induction of PGC-1α gene transcription, especially under conditions in which protein kinase A pathways were activated. This enhancement was associated with the interaction of PRDM16 with the PGC-1α promoter at the PPARα-binding site. In addition, PPARα promoted the expression of the PRDM16 gene in brown adipocytes, and activation of PPARα in human white adipocytes led to the appearance of a brown adipocyte pattern of gene expression, including induction of PGC-1α and PRDM16. Collectively, these results suggest that PPARα acts as a key component of brown fat thermogenesis by coordinately regulating lipid catabolism and thermogenic gene expression via induction of PGC-1α and PRDM16. PMID:22033933

  5. Histone deacetylase inhibitors block IFNγ-induced STAT1 phosphorylation.

    PubMed

    Ginter, Torsten; Bier, Carolin; Knauer, Shirley K; Sughra, Kalsoom; Hildebrand, Dagmar; Münz, Tobias; Liebe, Theresa; Heller, Regine; Henke, Andreas; Stauber, Roland H; Reichardt, Werner; Schmid, Johannes A; Kubatzky, Katharina F; Heinzel, Thorsten; Krämer, Oliver H

    2012-07-01

    Signal transducer and activator of transcription 1 (STAT1) is important for innate and adaptive immunity. Histone deacetylase inhibitors (HDACi) antagonize unbalanced immune functions causing chronic inflammation and cancer. Phosphorylation and acetylation regulate STAT1 and different IFNs induce phosphorylated STAT1 homo-/heterodimers, e.g. IFNα activates several STATs whereas IFNγ only induces phosphorylated STAT1 homodimers. In transformed cells HDACi trigger STAT1 acetylation linked to dephosphorylation by the phosphatase TCP45. It is unclear whether acetylation differentially affects STAT1 activated by IFNα or IFNγ, and if cellular responses to both cytokines depend on a phosphatase-dependent inactivation of acetylated STAT1. Here, we report that HDACi counteract IFN-induced phosphorylation of a critical tyrosine residue in the STAT1 C-terminus in primary cells and hematopoietic cells. STAT1 mutants mimicking a functionally inactive DNA binding domain (DBD) reveal that the number of acetylation-mimicking sites in STAT1 determines whether STAT1 is recruited to response elements after stimulation with IFNγ. Furthermore, we show that IFNα-induced STAT1 heterodimers carrying STAT1 molecules mimicking acetylation bind cognate DNA and provide innate anti-viral immunity. IFNγ-induced acetylated STAT1 homodimers are though inactive, suggesting that heterodimerization and complex formation can rescue STAT1 lacking a functional DBD. Apparently, the type of cytokine determines how acetylation affects the nuclear entry and DNA binding of STAT1. Our data contribute to a better understanding of STAT1 regulation by acetylation. PMID:22425562

  6. How Peroxisomes Affect Aflatoxin Biosynthesis in Aspergillus Flavus

    PubMed Central

    Reverberi, Massimo; Punelli, Marta; Smith, Carrie A.; Zjalic, Slaven; Scarpari, Marzia; Scala, Valeria; Cardinali, Giorgia; Aspite, Nicaela; Pinzari, Flavia; Payne, Gary A.; Fabbri, Anna A.; Fanelli, Corrado

    2012-01-01

    In filamentous fungi, peroxisomes are crucial for the primary metabolism and play a pivotal role in the formation of some secondary metabolites. Further, peroxisomes are important site for fatty acids ?-oxidation, the formation of reactive oxygen species and for their scavenging through a complex of antioxidant activities. Oxidative stress is involved in different metabolic events in all organisms and it occurs during oxidative processes within the cell, including peroxisomal ?-oxidation of fatty acids. In Aspergillus flavus, an unbalance towards an hyper-oxidant status into the cell is a prerequisite for the onset of aflatoxin biosynthesis. In our preliminary results, the use of bezafibrate, inducer of both peroxisomal ?-oxidation and peroxisome proliferation in mammals, significantly enhanced the expression of pex11 and foxA and stimulated aflatoxin synthesis in A. flavus. This suggests the existence of a correlation among peroxisome proliferation, fatty acids ?-oxidation and aflatoxin biosynthesis. To investigate this correlation, A. flavus was transformed with a vector containing P33, a gene from Cymbidium ringspot virus able to induce peroxisome proliferation, under the control of the promoter of the Cu,Zn-sod gene of A. flavus. This transcriptional control closely relates the onset of the antioxidant response to ROS increase, with the proliferation of peroxisomes in A. flavus. The AfP33 transformant strain show an up-regulation of lipid metabolism and an higher content of both intracellular ROS and some oxylipins. The combined presence of a higher amount of substrates (fatty acids-derived), an hyper-oxidant cell environment and of hormone-like signals (oxylipins) enhances the synthesis of aflatoxins in the AfP33 strain. The results obtained demonstrated a close link between peroxisome metabolism and aflatoxin synthesis. PMID:23094106

  7. Peroxisomes and Disease - An Overview

    PubMed Central

    Delille, Hannah K.; Bonekamp, Nina A.; Schrader, Michael

    2006-01-01

    Peroxisomes are indispensable for human health and development. They represent ubiquitous subcellular organelles which compartmentalize enzymes responsible for several crucial metabolic processes such as ?-oxidation of specific fatty acids, biosynthesis of ether phospholipids and metabolism of reactive oxygen species. Peroxisomes are highly flexible organelles that rapidly assemble, multiply and degrade in response to metabolic needs. Basic research on the biogenesis of peroxisomes and their metabolic functions have improved our knowledge about their crucial role in several inherited disorders and in other pathophysiological conditions. The goal of this review is to give a comprehensive overview of the role of peroxisomes in disease. Besides the genetic peroxisomal disorders in humans, the role of peroxisomes in carcinogenesis and in situations related to oxidative stress such as inflammation, ischemia-reperfusion, and diabetes will be addressed. PMID:23674998

  8. Hypervulnerability to Sound Exposure through Impaired Adaptive Proliferation of Peroxisomes.

    PubMed

    Delmaghani, Sedigheh; Defourny, Jean; Aghaie, Asadollah; Beurg, Maryline; Dulon, Didier; Thelen, Nicolas; Perfettini, Isabelle; Zelles, Tibor; Aller, Mate; Meyer, Anaïs; Emptoz, Alice; Giraudet, Fabrice; Leibovici, Michel; Dartevelle, Sylvie; Soubigou, Guillaume; Thiry, Marc; Vizi, E Sylvester; Safieddine, Saaid; Hardelin, Jean-Pierre; Avan, Paul; Petit, Christine

    2015-11-01

    A deficiency in pejvakin, a protein of unknown function, causes a strikingly heterogeneous form of human deafness. Pejvakin-deficient (Pjvk(-/-)) mice also exhibit variable auditory phenotypes. Correlation between their hearing thresholds and the number of pups per cage suggest a possible harmful effect of pup vocalizations. Direct sound or electrical stimulation show that the cochlear sensory hair cells and auditory pathway neurons of Pjvk(-/-) mice and patients are exceptionally vulnerable to sound. Subcellular analysis revealed that pejvakin is associated with peroxisomes and required for their oxidative-stress-induced proliferation. Pjvk(-/-) cochleas display features of marked oxidative stress and impaired antioxidant defenses, and peroxisomes in Pjvk(-/-) hair cells show structural abnormalities after the onset of hearing. Noise exposure rapidly upregulates Pjvk cochlear transcription in wild-type mice and triggers peroxisome proliferation in hair cells and primary auditory neurons. Our results reveal that the antioxidant activity of peroxisomes protects the auditory system against noise-induced damage. PMID:26544938

  9. Peroxisomal cholesterol biosynthesis and Smith-Lemli-Opitz syndrome

    SciTech Connect

    Weinhofer, Isabelle; Kunze, Markus; Stangl, Herbert; Porter, Forbes D.; Berger, Johannes . E-mail: johannes.berger@meduniwien.ac.at

    2006-06-23

    Smith-Lemli-Opitz syndrome (SLOS), caused by 7-dehydrocholesterol-reductase (DHCR7) deficiency, shows variable severity independent of DHCR7 genotype. To test whether peroxisomes are involved in alternative cholesterol synthesis, we used [1-{sup 14}C]C24:0 for peroxisomal {beta}-oxidation to generate [1-{sup 14}C]acetyl-CoA as cholesterol precursor inside peroxisomes. The HMG-CoA reductase inhibitor lovastatin suppressed cholesterol synthesis from [2-{sup 14}C]acetate and [1-{sup 14}C]C8:0 but not from [1-{sup 14}C]C24:0, implicating a peroxisomal, lovastatin-resistant HMG-CoA reductase. In SLOS fibroblasts lacking DHCR7 activity, no cholesterol was formed from [1-{sup 14}C]C24:0-derived [1-{sup 14}C]acetyl-CoA, indicating that the alternative peroxisomal pathway also requires this enzyme. Our results implicate peroxisomes in cholesterol biosynthesis but provide no link to phenotypic variation in SLOS.

  10. Dual targeting of peroxisomal proteins

    PubMed Central

    Ast, Julia; Stiebler, Alina C.; Freitag, Johannes; Blker, Michael

    2013-01-01

    Cellular compartmentalization into organelles serves to separate biological processes within the environment of a single cell. While some metabolic reactions are specific to a single organelle, others occur in more than one cellular compartment. Specific targeting of proteins to compartments inside of eukaryotic cells is mediated by defined sequence motifs. To achieve multiple targeting to different compartments cells use a variety of strategies. Here, we focus on mechanisms leading to dual targeting of peroxisomal proteins. In many instances, isoforms of peroxisomal proteins with distinct intracellular localization are encoded by separate genes. But also single genes can give rise to differentially localized proteins. Different isoforms can be generated by use of alternative transcriptional start sites, by differential splicing or ribosomal read-through of stop codons. In all these cases different peptide variants are produced, of which only one carries a peroxisomal targeting signal. Alternatively, peroxisomal proteins contain additional signals that compete for intracellular targeting. Dual localization of proteins residing in both the cytoplasm and in peroxisomes may also result from use of inefficient targeting signals. The recent observation that some bona fide cytoplasmic enzymes were also found in peroxisomes indicates that dual targeting of proteins to both the cytoplasm and the peroxisome might be more widespread. Although current knowledge of proteins exhibiting only partial peroxisomal targeting is far from being complete, we speculate that the metabolic capacity of peroxisomes might be larger than previously assumed. PMID:24151469

  11. Phosphatidylcholine Supply to Peroxisomes of the Yeast Saccharomyces cerevisiae

    PubMed Central

    Ramprecht, Claudia; Zellnig, Günther; Leitner, Erich; Hermetter, Albin; Daum, Günther

    2015-01-01

    In the yeast Saccharomyces cerevisiae, phosphatidylcholine (PC), the major phospholipid (PL) of all organelle membranes, is synthesized via two different pathways. Methylation of phosphatidylethanolamine (PE) catalyzed by the methyl transferases Cho2p/Pem1p and Opi3p/Pem2p as well as incorporation of choline through the CDP (cytidine diphosphate)-choline branch of the Kennedy pathway lead to PC formation. To determine the contribution of these two pathways to the supply of PC to peroxisomes (PX), yeast mutants bearing defects in the two pathways were cultivated under peroxisome inducing conditions, i.e. in the presence of oleic acid, and subjected to biochemical and cell biological analyses. Phenotype studies revealed compromised growth of both the cho20Δopi3Δ (mutations in the methylation pathway) and the cki1Δdpl1Δeki1Δ (mutations in the CDP-choline pathway) mutant when grown on oleic acid. Analysis of peroxisomes from the two mutant strains showed that both pathways produce PC for the supply to peroxisomes, although the CDP-choline pathway seemed to contribute with higher efficiency than the methylation pathway. Changes in the peroxisomal lipid pattern of mutants caused by defects in the PC biosynthetic pathways resulted in changes of membrane properties as shown by anisotropy measurements with fluorescent probes. In summary, our data define the origin of peroxisomal PC and demonstrate the importance of PC for peroxisome membrane formation and integrity. PMID:26241051

  12. The NADPH oxidase inhibitor apocynin (acetovanillone) induces oxidative stress

    SciTech Connect

    Riganti, Chiara . E-mail: dario.ghigo@unito.it

    2006-05-01

    Apocynin (acetovanillone) is often used as a specific inhibitor of NADPH oxidase. In N11 glial cells, apocynin induced, in a dose-dependent way, a significant increase of both malonyldialdehyde level (index of lipid peroxidation) and lactate dehydrogenase release (index of a cytotoxic effect). Apocynin evoked also, in a significant way, an increase of H{sub 2}O{sub 2} concentration and a decrease of the intracellular glutathione/glutathione disulfide ratio, accompanied by augmented efflux of glutathione and glutathione disulfide. Apocynin induced the activation of both pentose phosphate pathway and tricarboxylic acid cycle, which was blocked when the cells were incubated with glutathione together with apocynin. The cell incubation with glutathione prevented also the apocynin-induced increase of malonyldialdehyde generation and lactate dehydrogenase leakage. Apocynin exerted an oxidant effect also in a cell-free system: indeed, in aqueous solution, it evoked a faster oxidation of the thiols glutathione and dithiothreitol, and elicited the generation of reactive oxygen species, mainly superoxide anions. Our results suggest that apocynin per se can induce an oxidative stress and exert a cytotoxic effect in N11 cells and other cell types, and that some effects of apocynin in in vitro and in vivo experimental models should be interpreted with caution.

  13. Peroxisome Proliferator-activated Receptor ? (PPAR?) Mediates a Ski Oncogene-induced Shift from Glycolysis to Oxidative Energy Metabolism*?

    PubMed Central

    Ye, Fang; Lemieux, Hlne; Hoppel, Charles L.; Hanson, Richard W.; Hakimi, Parvin; Croniger, Colleen M.; Puchowicz, Michelle; Anderson, Vernon E.; Fujioka, Hisashi; Stavnezer, Ed

    2011-01-01

    Overexpression of the Ski oncogene induces oncogenic transformation of chicken embryo fibroblasts (CEFs). However, unlike most other oncogene-transformed cells, Ski-transformed CEFs (Ski-CEFs) do not display the classical Warburg effect. On the contrary, Ski transformation reduced lactate production and glucose utilization in CEFs. Compared with CEFs, Ski-CEFs exhibited enhanced TCA cycle activity, fatty acid catabolism through ?-oxidation, glutamate oxidation, oxygen consumption, as well as increased numbers and mass of mitochondria. Interestingly, expression of PPAR?, a key transcription factor that regulates adipogenesis and lipid metabolism, was dramatically elevated at both the mRNA and protein levels in Ski-CEFs. Accordingly, PPAR? target genes that are involved in lipid uptake, transport, and oxidation were also markedly up-regulated by Ski. Knocking down PPAR? in Ski-CEFs by RNA interference reversed the elevated expression of these PPAR? target genes, as well as the shift to oxidative metabolism and the increased mitochondrial biogenesis. Moreover, we found that Ski co-immunoprecipitates with PPAR? and co-activates PPAR?-driven transcription. PMID:21917928

  14. Selective HDAC1/HDAC2 Inhibitors Induce Neuroblastoma Differentiation

    PubMed Central

    Frumm, Stacey M.; Fan, Zi Peng; Ross, Kenneth N.; Duvall, Jeremy R.; Gupta, Supriya; VerPlank, Lynn; Suh, Byung-Chul; Holson, Edward; Wagner, Florence F.; Smith, William B.; Paranal, Ronald M.; Bassil, Christopher F.; Qi, Jun; Roti, Giovanni; Kung, Andrew L.; Bradner, James E.; Tolliday, Nicola; Stegmaier, Kimberly

    2013-01-01

    Summary While cytotoxic chemotherapy remains the hallmark of cancer treatment, intensive regimens fall short in many malignancies, including high-risk neuroblastoma. One alternative strategy is to therapeutically promote tumor differentiation. We created a gene expression signature to measure neuroblast maturation, adapted it to a high-throughput platform, and screened a diversity oriented synthesis-generated small-molecule library for differentiation inducers. We identified BRD8430, containing a nine-membered lactam, an ortho-amino anilide functionality, and three chiral centers, as a selective Class I histone deacetylase (HDAC) inhibitor (HDAC1>2>3). Further investigation demonstrated that selective HDAC1/HDAC2 inhibition using compounds or RNA interference induced differentiation and decreased viability in neuroblastoma cell lines. Combined treatment with 13-cis retinoic acid augmented these effects and enhanced activation of retinoic acid signaling. Therefore, by applying a chemical genomic screening approach we identified selective HDAC1/HDAC2 inhibition as a strategy to induce neuroblastoma differentiation. PMID:23706636

  15. Peroxisomes contribute to reactive oxygen species homeostasis and cell division induction in Arabidopsis protoplasts

    PubMed Central

    Tiew, Terence W.-Y.; Sheahan, Michael B.; Rose, Ray J.

    2015-01-01

    The ability to induce Arabidopsis protoplasts to dedifferentiate and divide provides a convenient system to analyze organelle dynamics in plant cells acquiring totipotency. Using peroxisome-targeted fluorescent proteins, we show that during protoplast culture, peroxisomes undergo massive proliferation and disperse uniformly around the cell before cell division. Peroxisome dispersion is influenced by the cytoskeleton, ensuring unbiased segregation during cell division. Considering their role in oxidative metabolism, we also investigated how peroxisomes influence homeostasis of reactive oxygen species (ROS). Protoplast isolation induces an oxidative burst, with mitochondria the likely major ROS producers. Subsequently ROS levels in protoplast cultures decline, correlating with the increase in peroxisomes, suggesting that peroxisome proliferation may also aid restoration of ROS homeostasis. Transcriptional profiling showed up-regulation of several peroxisome-localized antioxidant enzymes, most notably catalase (CAT). Analysis of antioxidant levels, CAT activity and CAT isoform 3 mutants (cat3) indicate that peroxisome-localized CAT plays a major role in restoring ROS homeostasis. Furthermore, protoplast cultures of pex11a, a peroxisome division mutant, and cat3 mutants show reduced induction of cell division. Taken together, the data indicate that peroxisome proliferation and CAT contribute to ROS homeostasis and subsequent protoplast division induction. PMID:26379686

  16. Evolving models for peroxisome biogenesis?

    PubMed Central

    Hettema, Ewald H; Erdmann, Ralf; van der Klei, Ida; Veenhuis, Marten

    2014-01-01

    Significant progress has been made towards our understanding of the mechanism of peroxisome formation, in particular concerning sorting of peroxisomal membrane proteins, matrix protein import and organelle multiplication. Here we evaluate the progress made in recent years. We focus mainly on progress made in yeasts. We indicate the gaps in our knowledge and discuss conflicting models. PMID:24681485

  17. Inhibitors of Fatty Acid Synthesis Induce PPAR?-Regulated Fatty Acid ?-Oxidative Genes: Synergistic Roles of L-FABP and Glucose

    PubMed Central

    Huang, Huan; McIntosh, Avery L.; Martin, Gregory G.; Petrescu, Anca D.; Landrock, Kerstin K.; Landrock, Danilo; Kier, Ann B.; Schroeder, Friedhelm

    2013-01-01

    While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor-? (PPAR?) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20?mM) but not physiological (6?mM) glucose conferred on both TOFA and C75 the ability to induce PPAR? transcription of the fatty acid ?-oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR? in the context of high glucose at levels similar to those in uncontrolled diabetes. PMID:23533380

  18. Small-Scale Purification of Peroxisomes for Analytical Applications.

    PubMed

    Cramer, Jana; Effelsberg, Daniel; Girzalsky, Wolfgang; Erdmann, Ralf

    2015-09-01

    This protocol describes the isolation of peroxisomes from Saccharomyces cerevisiae by density gradient centrifugation using a sucrose, OptiPrep, or OptiPrep/sucrose gradient. Oleic acid-induced cells are first converted to spheroplasts using lyticase for cell wall digestion. Spheroplasts are homogenized, and nuclei and cell debris are removed by low-speed centrifugation to produce a postnuclear supernatant (PNS). Separation of the PNS by density gradient centrifugation is suitable for many analytical applications; however, to increase the yield of peroxisomes, further fractionation of the PNS is possible. Differential centrifugation of the PNS allows removal of the cytosol and other contaminating organelles, resulting in an organellar pellet (OP) enriched in peroxisomes and mitochondria that can be loaded onto the density gradient. Following density gradient centrifugation of the PNS or OP, fractions are collected from the bottom of the centrifuge tube. The distribution of organelles, including peroxisome peak fractions, is characterized by measurement of marker enzyme activity. PMID:26330620

  19. Effects of vitamin E on peroxisome proliferator-activated receptor ? and nuclear factor-erythroid 2-related factor 2 in hypercholesterolemia-induced atherosclerosis.

    PubMed

    Bozaykut, Perinur; Karademir, Betul; Yazgan, Burak; Sozen, Erdi; Siow, Richard C M; Mann, Giovanni E; Ozer, Nesrin Kartal

    2014-05-01

    Atherosclerosis and associated cardiovascular complications such as stroke and myocardial infarction are major causes of morbidity and mortality. We have previously reported a significant increase in mRNA levels of the scavenger receptor CD36 in aortae of cholesterol-fed rabbits and shown that vitamin E treatment attenuated increased CD36 mRNA expression. In the present study, we further investigated the redox signaling pathways associated with protection against atherogenesis induced by high dietary cholesterol and correlated these with CD36 expression and the effects of vitamin E supplementation in a rabbit model. Male albino rabbits were assigned to either a control group fed with a low vitamin E diet alone or a test group fed with a low vitamin E diet containing 2% cholesterol in the absence or presence of daily intramuscular injections of vitamin E (50mg/kg). To elucidate the mechanisms by which vitamin E supplementation alters the effects of hypercholesterolemia in rabbit aortae, we measured peroxisome proliferator-activated receptor ? (PPAR?), ATP-binding cassette transporter A1 (ABCA1), and matrix metalloproteinase-1 (MMP-1) mRNA levels by quantitative RT-PCR and the expression of MMP-1, nuclear factor-erythroid 2-related factor 2 (Nrf2), and glutathione S-transferase ? (GST?) protein by immunoblotting. The increased MMP-1 and decreased GST? expression observed suggests that a cholesterol-rich diet contributes to the development of atherosclerosis, whereas vitamin E supplementation affords protection by decreasing MMP-1 and increasing PPAR?, GST?, and ABCA1 levels in aortae of rabbits fed a cholesterol-rich diet. Notably, protein expression of Nrf2, the antioxidant transcription factor, was increased in both the cholesterol-fed and the vitamin E-supplemented groups. Although Nrf2 activation can promote CD36-mediated cholesterol uptake by macrophages, the increased induction of Nrf2-mediated antioxidant genes is likely to contribute to decreased lesion progression. Thus, our study demonstrates that Nrf2 can mediate both pro- and antiatherosclerotic effects. PMID:24583459

  20. Small GTPases in peroxisome dynamics.

    PubMed

    Just, Wilhelm W; Peränen, Johan

    2016-05-01

    In this review article, we summarize current knowledge on peroxisome biogenesis/functions and the role that small GTPases may play in these processes. Precise intracellular distribution of cell organelles requires their regulated association to microtubules and the actin cytoskeleton. In this respect, RhoGDP/RhoGTP favor binding of peroxisomes to microtubules and actin filaments. In its GTP-bound form, RhoA activates a regulatory cascade involving Rho kinaseII and non-muscle myosinIIA. Such interactions frequently depend on phosphoinositides (PIs) of which PI4P, PI(4,5)P2, and PI(3,5)P2 were found to be present in the peroxisomal membrane. PIs are pivotal determinants of intracellular signaling and known to regulate a wide range of cellular functions. In many of these functions, small GTPases are implicated. The small GTPase ADP-ribosylation factor 1 (Arf1), for example, is known to stimulate synthesis of PI4P and PI(4,5)P2 on the Golgi to regulate protein and lipid sorting. In vitro binding assays localized Arf1 and the COPI complex to peroxisomes. In light of the recent discussion of pre-peroxisomal vesicle generation at the ER, peroxisomal Arf1-COPI vesicles may serve retrograde transport of ER-resident components. A mass spectrometric screen localized various Rab proteins to peroxisomes. Overexpression of these proteins in combination with laser-scanning fluorescence microscopy co-localized Rab6, Rab8, Rab10, Rab14, and Rab18 with peroxisomal structures. By analogy to the role these proteins play in other organelle dynamics, we may envisage what the function of these proteins may be in relation to the peroxisomal compartment. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26775587

  1. Mode of action framework analysis for receptor-mediated toxicity: the Peroxisome Proliferator-Activated Receptor alpha (PPAR?) as a case study

    EPA Science Inventory

    Therapeutic hypolipidemic agents and industrial chemicals that cause peroxisome proliferation and induce liver tumors in rodents activate the nuclear receptor peroxisome proliferator-activated receptor alpha (PPAR?). Research has elucidated the cellular and molecular events by w...

  2. Mode of action framework analysis for receptor-mediated toxicity: the Peroxisome Proliferator-Activated Receptor alpha (PPARα) as a case study

    EPA Science Inventory

    Therapeutic hypolipidemic agents and industrial chemicals that cause peroxisome proliferation and induce liver tumors in rodents activate the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα). Research has elucidated the cellular and molecular events by w...

  3. Hypoxia-inducible factor 1 mediates hypoxia-induced cardiomyocyte lipid accumulation by reducing the DNA binding activity of peroxisome proliferator-activated receptor {alpha}/retinoid X receptor

    SciTech Connect

    Belanger, Adam J.; Luo Zhengyu; Vincent, Karen A.; Akita, Geoffrey Y.; Cheng, Seng H.; Gregory, Richard J.; Jiang Canwen

    2007-12-21

    In response to cellular hypoxia, cardiomyocytes adapt to consume less oxygen by shifting ATP production from mitochondrial fatty acid {beta}-oxidation to glycolysis. The transcriptional activation of glucose transporters and glycolytic enzymes by hypoxia is mediated by hypoxia-inducible factor 1 (HIF-1). In this study, we examined whether HIF-1 was involved in the suppression of mitochondrial fatty acid {beta}-oxidation in hypoxic cardiomyocytes. We showed that either hypoxia or adenovirus-mediated expression of a constitutively stable hybrid form (HIF-1{alpha}/VP16) suppressed mitochondrial fatty acid metabolism, as indicated by an accumulation of intracellular neutral lipid. Both treatments also reduced the mRNA levels of muscle carnitine palmitoyltransferase I which catalyzes the rate-limiting step in the mitochondrial import of fatty acids for {beta}-oxidation. Furthermore, adenovirus-mediated expression of HIF-1{alpha}/VP16 in cardiomyocytes under normoxic conditions also mimicked the reduction in the DNA binding activity of peroxisome proliferator-activated receptor {alpha} (PPAR{alpha})/retinoid X receptor (RXR), in the presence or absence of a PPAR{alpha} ligand. These results suggest that HIF-1 may be involved in hypoxia-induced suppression of fatty acid metabolism in cardiomyocytes by reducing the DNA binding activity of PPAR{alpha}/RXR.

  4. Hepatic dysfunction in peroxisomal disorders.

    PubMed

    Baes, Myriam; Van Veldhoven, Paul P

    2016-05-01

    The peroxisomal compartment in hepatocytes hosts several essential metabolic conversions. These are defective in peroxisomal disorders that are either caused by failure to import the enzymes in the organelle or by mutations in the enzymes or in transporters needed to transfer the substrates across the peroxisomal membrane. Hepatic pathology is one of the cardinal features in disorders of peroxisome biogenesis and peroxisomal β-oxidation although it only rarely determines the clinical fate. In mouse models of these diseases liver pathologies also occur, although these are not always concordant with the human phenotype which might be due to differences in diet, expression of enzymes and backup mechanisms. Besides the morphological changes, we overview the impact of peroxisome malfunction on other cellular compartments including mitochondria and the ER. We further focus on the metabolic pathways that are affected such as bile acid formation, and dicarboxylic acid and branched chain fatty acid degradation. It appears that the association between deregulated metabolites and pathological events remains unclear. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26453805

  5. Isolation of Peroxisomes from Yeast.

    PubMed

    Cramer, Jana; Effelsberg, Daniel; Girzalsky, Wolfgang; Erdmann, Ralf

    2015-09-01

    Peroxisomes are multifunctional, dynamic organelles present in nearly all eukaryotic cells. Determining their structural and functional characteristics often requires obtaining isolated and purified peroxisomes via subcellular fractionation. Subcellular fractionation techniques are generally based on a three-step procedure: preparation of a cell-free homogenate (postnuclear supernatant), generation of an organellar pellet by differential centrifugation, and density gradient centrifugation. Here we introduce methods for small-scale isolation of peroxisomes from yeast cells using different gradient media as well as large-scale purification using a two-step gradient centrifugation. PMID:26330630

  6. The peroxisome: still a mysterious organelle

    PubMed Central

    Fahimi, H. Dariush

    2008-01-01

    More than half a century of research on peroxisomes has revealed unique features of this ubiquitous subcellular organelle, which have often been in disagreement with existing dogmas in cell biology. About 50 peroxisomal enzymes have so far been identified, which contribute to several crucial metabolic processes such as ?-oxidation of fatty acids, biosynthesis of ether phospholipids and metabolism of reactive oxygen species, and render peroxisomes indispensable for human health and development. It became obvious that peroxisomes are highly dynamic organelles that rapidly assemble, multiply and degrade in response to metabolic needs. However, many aspects of peroxisome biology are still mysterious. This review addresses recent exciting discoveries on the biogenesis, formation and degradation of peroxisomes, on peroxisomal dynamics and division, as well as on the interaction and cross talk of peroxisomes with other subcellular compartments. Furthermore, recent advances on the role of peroxisomes in medicine and in the identification of novel peroxisomal proteins are discussed. PMID:18274771

  7. Proton pump inhibitor-induced exfoliative dermatitis: A case report

    PubMed Central

    QIU, ZHIHONG; LIU, HONGTAO; HE, LIEN; MA, YINLING; SONG, HAOJING; BAI, WANJUN; YU, MEILING

    2016-01-01

    A 74-year-old female patient was admitted to hospital following a road accident with pains in the chest, abdomen, waist, back, nose, left wrist and lower limbs. After 1 week, the patient presented with gastrointestinal bleeding, and thus was treated with protein pump inhibitors (PPIs), including lansoprazole, esomeprazole and omeprazole enteric-coated tablets, in order to inhibit acid secretion and attenuate bleeding. However, the patient developed skin rashes on the chest and right lower limb and foot 28 days following treatment initiation. The skin rashes spread and ulcerated after 3 days, and were associated with tracheal mucosal injury and hemoptysis. Subsequently, treatment of the patient with PPIs was terminated, after which the tracheal hemoptysis and skin rashes markedly improved. In addition, no new skin rashes appeared following termination of the PPI treatment. In the present case, long-term treatment of an elderly patient with PPIs may have induced exfoliative dermatitis, due to hepatic ischemia, hypoxia and acute renal failure, which may have decreased the metabolism of PPIs, resulting in the accumulation of PPI metabolites. PMID:26893644

  8. Integrin Inhibitor Suppresses Bevacizumab-Induced Glioma Invasion12

    PubMed Central

    Ishida, Joji; Onishi, Manabu; Kurozumi, Kazuhiko; Ichikawa, Tomotsugu; Fujii, Kentaro; Shimazu, Yosuke; Oka, Tetsuo; Date, Isao

    2014-01-01

    Glioblastoma is known to secrete high levels of vascular endothelial growth factor (VEGF), and clinical studies with bevacizumab, a monoclonal antibody to VEGF, have demonstrated convincing therapeutic benefits in glioblastoma patients. However, its induction of invasive proliferation has also been reported. We examined the effects of treatment with cilengitide, an integrin inhibitor, on bevacizumab-induced invasive changes in glioma. U87?EGFR cells were stereotactically injected into the brain of nude mice or rats. Five days after tumor implantation, cilengitide and bevacizumab were administered intraperitoneally three times a week. At 18 days after tumor implantation, the brains were removed and observed histopathologically. Next, the bevacizumab and cilengitide combination group was compared to the bevacizumab monotherapy group using microarray analysis. Bevacizumab treatment led to increased cell invasion in spite of decreased angiogenesis. When the rats were treated with a combination of bevacizumab and cilengitide, the depth of tumor invasion was significantly less than with only bevacizumab. Pathway analysis demonstrated the inhibition of invasion-associated genes such as the integrin-mediated cell adhesion pathway in the combination group. This study showed that the combination of bevacizumab with cilengitide exerted its anti-invasive effect. The elucidation of this mechanism might contribute to the treatment of bevacizumab-refractory glioma. PMID:24704537

  9. Peroxisome homeostasis: Mechanisms of division and selective degradation of peroxisomes in mammals.

    PubMed

    Honsho, Masanori; Yamashita, Shun-Ichi; Fujiki, Yukio

    2016-05-01

    Peroxisome number and quality are maintained by its biogenesis and turnover and are important for the homeostasis of peroxisomes. Peroxisomes are increased in number by division with dynamic morphological changes including elongation, constriction, and fission. In the course of peroxisomal division, peroxisomal morphogenesis is orchestrated by Pex11β, dynamin-like protein 1 (DLP1), and mitochondrial fission factor (Mff). Conversely, peroxisome number is reduced by its degradation. Peroxisomes are mainly degraded by pexophagy, a type of autophagy specific for peroxisomes. Upon pexophagy, an adaptor protein translocates on peroxisomal membrane and connects peroxisomes to autophagic machineries. Molecular mechanisms of pexophagy are well studied in yeast systems where several specific adaptor proteins are identified. Pexophagy in mammals also proceeds in a manner dependent on adaptor proteins. In this review, we address the recent progress in studies on peroxisome morphogenesis and pexophagy. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26434997

  10. Maternal protein restriction induces early-onset glucose intolerance and alters hepatic genes expression in the peroxisome proliferator-activated receptor pathway in offspring

    PubMed Central

    Zheng, Jia; Xiao, Xinhua; Zhang, Qian; Yu, Miao; Xu, Jianping; Wang, Zhixin

    2015-01-01

    Aims/Introduction Maternal undernutrition during pregnancy and/or lactation can alter the offspring's response to environmental challenges, and thus increases the risk of the development of metabolic diseases at a later age. However, whether maternal protein restriction can modulate glucose metabolism in the early life of offspring is less understood. Furthermore, we explored the potential underlying mechanisms that illustrate this phenotype. Materials and Methods To test this hypothesis, we examined the offspring of C57BL/6J mice at weaning to determine the effects of feeding their mothers a low-protein diet or normal chow diet throughout pregnancy and lactation. Gene array experiments and quantitative real-time polymerase chain reaction were utilized to explore the altered hepatic genes expression. Results The offspring of dams fed a low-protein diet had a lower birthweight and bodyweight, impaired glucose tolerance, decreased insulin sensitivity, and decreased serum cholesterol at weaning. Using gene array experiments, 253 differentially expressed genes were identified in the liver tissues of the offspring between the two groups. Bioinformatic analyses showed that all differentially expressed genes were mapped to 11 pathways. We focused on the ‘peroxisome proliferator-activated receptor signaling pathway,’ because peroxisome proliferator-activated receptors have emerged as central regulators of glucose and lipid homeostasis. Quantitative real-time polymerase chain reaction was utilized for the validation of genes in the pathway. Conclusions A maternal low-protein diet during pregnancy and lactation promotes early-onset glucose intolerance in the offspring mice, and the altered hepatic genes expression in peroxisome proliferator-activated receptor signaling pathway could play role in regulating this phenomenon. PMID:25969711

  11. Pexophagy and peroxisomal protein turnover in plants.

    PubMed

    Young, Pierce G; Bartel, Bonnie

    2016-05-01

    Peroxisomes are dynamic, vital organelles that sequester a variety of oxidative reactions and their toxic byproducts from the remainder of the cell. The oxidative nature of peroxisomal metabolism predisposes the organelle to self-inflicted damage, highlighting the need for a mechanism to dispose of damaged peroxisomes. In addition, the metabolic requirements of plant peroxisomes change during development, and obsolete peroxisomal proteins are degraded. Although pexophagy, the selective autophagy of peroxisomes, is an obvious mechanism for executing such degradation, pexophagy has only recently been described in plants. Several recent studies in the reference plant Arabidopsis thaliana implicate pexophagy in the turnover of peroxisomal proteins, both for quality control and during functional transitions of peroxisomal content. In this review, we describe our current understanding of the occurrence, roles, and mechanisms of pexophagy in plants. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26348128

  12. Regulation of peroxisome dynamics by phosphorylation.

    PubMed

    Oeljeklaus, Silke; Schummer, Andreas; Mastalski, Thomas; Platta, Harald W; Warscheid, Bettina

    2016-05-01

    Peroxisomes are highly dynamic organelles that can rapidly change in size, abundance, and protein content in response to alterations in nutritional and other environmental conditions. These dynamic changes in peroxisome features, referred to as peroxisome dynamics, rely on the coordinated action of several processes of peroxisome biogenesis. Revealing the regulatory mechanisms of peroxisome dynamics is an emerging theme in cell biology. These mechanisms are inevitably linked to and synchronized with the biogenesis and degradation of peroxisomes. To date, the key players and basic principles of virtually all steps in the peroxisomal life cycle are known, but regulatory mechanisms remained largely elusive. A number of recent studies put the spotlight on reversible protein phosphorylation for the control of peroxisome dynamics and highlighted peroxisomes as hubs for cellular signal integration and regulation. Here, we will present and discuss the results of several studies performed using yeast and mammalian cells that convey a sense of the impact protein phosphorylation may have on the modulation of peroxisome dynamics by regulating peroxisomal matrix and membrane protein import, proliferation, inheritance, and degradation. We further put forward the idea to make use of current data on phosphorylation sites of peroxisomal and peroxisome-associated proteins reported in advanced large-scale phosphoproteomic studies. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26775584

  13. Assembly, maintenance and dynamics of peroxisomes.

    PubMed

    Erdmann, Ralf

    2016-05-01

    Peroxisomes are ubiquitous organelles of eukaryotic cells, and it is becoming increasingly clear that the biogenesis of these multi-purpose organelles is more complex than initially anticipated. Along this line, peroxisomes exhibit features, which clearly distinguish them from other cellular organelles, like their ability to import folded proteins or their capability to form de novo. However, further insight into the cellular life of peroxisomes also revealed features that they share with other organelles, such as organelle fission or regulated degradation by autophagy, that are similar for peroxisomes, mitochondria and chloroplasts. This special issue highlights recent progress in the understanding of the biogenesis of peroxisomes with emphasis on the assembly, maintenance and dynamics of the organelles. In particular, it focuses on the following areas: (i) topogenesis of peroxisomal matrix proteins as well as the structure and function of peroxisomal protein import machineries. (ii) Peroxisomal targeting of membrane proteins and de novo formation of peroxisomes. (iii) Maintenance of peroxisomes in health and disease. (iv) Proliferation and regulated degradation of peroxisomes. (v) Motility and inheritance of peroxisomes. (vi) Role of peroxisomes in the cellular context. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26851075

  14. PROTEASOME INHIBITORS INDUCE APOPTOSIS OF PROSTATE CANCER CELLS BY INDUCING NUCLEAR TRANSLOCATION OF I?B?

    PubMed Central

    Vu, Hai-Yen; Juvekar, Ashish; Ghosh, Chandra; Ramaswami, Sitharam; Le, Dung Hong; Vancurova, Ivana

    2008-01-01

    Proteasome inhibitors are known to suppress the proteasome-mediated degradation of I?B? in stimulated cells. This results in the cytoplasmic retention of NF?B and its reduced nuclear transcriptional activity. In this study, we show that in the metastatic prostate cancer cells, the proteasome inhibitors exhibit a novel, previously unrecognized effect: they increase the cellular levels of I?B?, which then translocates to the nucleus, associates with the nuclear p65 NF?B, thus inhibiting the constitutive NF?B DNA binding activity and inducing apoptosis. The proteasome inhibition-induced nuclear translocation of I?B? is dependent on de novo protein synthesis, occurs also in other cell types, and does not require I?B? phosphorylation on Ser-32. Since NF?B activity is constitutively increased in many human cancers as well as in inflammatory disorders, the proteasome inhibition-induced nuclear translocation of I?B? could thus provide a new therapeutic strategy aimed at the specific inhibition of NF?B activity by the nuclear I?B?. PMID:18468507

  15. Proteasome inhibitors induce apoptosis of prostate cancer cells by inducing nuclear translocation of IkappaBalpha.

    PubMed

    Vu, Hai-Yen; Juvekar, Ashish; Ghosh, Chandra; Ramaswami, Sitharam; Le, Dung Hong; Vancurova, Ivana

    2008-07-15

    Proteasome inhibitors are known to suppress the proteasome-mediated degradation of IkappaBalpha in stimulated cells. This results in the cytoplasmic retention of NFkappaB and its reduced nuclear transcriptional activity. In this study, we show that in the metastatic prostate cancer cells, the proteasome inhibitors exhibit a novel, previously unrecognized effect: they increase the cellular levels of IkappaBalpha, which then translocates to the nucleus, associates with the nuclear p65 NFkappaB, thus inhibiting the constitutive NFkappaB DNA binding activity and inducing apoptosis. The proteasome inhibition-induced nuclear translocation of IkappaBalpha is dependent on de novo protein synthesis, occurs also in other cell types, and does not require IkappaBalpha phosphorylation on Ser-32. Since NFkappaB activity is constitutively increased in many human cancers as well as in inflammatory disorders, the proteasome inhibition-induced nuclear translocation of IkappaBalpha could thus provide a new therapeutic strategy aimed at the specific inhibition of NFkappaB activity by the nuclear IkappaBalpha. PMID:18468507

  16. Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis.

    PubMed

    Motley, Alison M; Galvin, Paul C; Ekal, Lakhan; Nuttall, James M; Hettema, Ewald H

    2015-12-01

    A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum-derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division. PMID:26644516

  17. Selective Serotonin Reuptake Inhibitor-Induced Sexual Dysfunction in Adolescents: A Review.

    ERIC Educational Resources Information Center

    Scharko, Alexander M.

    2004-01-01

    Objective: To review the existing literature on selective serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction in adolescents. Method: A literature review of SSRI-induced adverse effects in adolescents focusing on sexual dysfunction was done. Nonsexual SSRI-induced adverse effects were compared in adult and pediatric populations.…

  18. Acneiform eruptions induced by epidermal growth factor receptor inhibitors: treatment with oral isotretinoin.

    PubMed

    Requena, Celia; Llombart, Beatriz; Sanmartn, Onofre

    2012-08-01

    The most common cutaneous side effects to epidermal growth factor receptor (EGFR) inhibitors are follicular or acneiform eruptions, nail disorders, xerosis, and desquamation. Although topical and oral antibiotics with or without topical corticosteroids usually are safe and effective treatment options for acneiform eruptions due to EGFR inhibitors, they are not always successful in refractory cases. We report 3 cases of severe acneiform eruptions induced by EGFR inhibitors that were successfully treated with oral isotretinoin. Complete response was observed in all 3 patients. We recommend oral isotretinoin for the management of acneiform reactions to EGFR inhibitors when the lesions persist or worsen despite antibiotic treatment. PMID:22988651

  19. Multiple Pathways for Protein Transport to Peroxisomes

    PubMed Central

    Kim, P.K.; Hettema, E.H.

    2015-01-01

    Peroxisomes are unique among the organelles of the endomembrane system. Unlike other organelles that derive most if not all of their proteins from the ER (endoplasmic reticulum), peroxisomes contain dedicated machineries for import of matrix proteins and insertion of membrane proteins. However, peroxisomes are also able to import a subset of their membrane proteins from the ER. One aspect of peroxisome biology that has remained ill defined is the role the various import pathways play in peroxisome maintenance. In this review, we discuss the available data on matrix and membrane protein import into peroxisomes. PMID:25681696

  20. Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

    SciTech Connect

    Sharma, Bhupesh Sharma, P.M.

    2013-11-15

    Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment of learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good potential in As induced VaD.

  1. The Synergistic Enhancement of Cloning Efficiency in Individualized Human Pluripotent Stem Cells by Peroxisome Proliferative-activated Receptor-? (PPAR?) Activation and Rho-associated Kinase (ROCK) Inhibition.

    PubMed

    Kajabadi, Nasim-Sadat; Ghoochani, Ali; Peymani, Maryam; Ghaedi, Kamran; Kiani-Esfahani, Abbas; Hashemi, Motahareh-Sadat; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein

    2015-10-23

    Although human pluripotent stem cells (hPSCs) provide valuable sources for regenerative medicine, their applicability is dependent on obtaining both suitable up-scaled and cost effective cultures. The Rho-associated kinase (ROCK) inhibitor Y-27632 permits hPSC survival upon dissociation; however, cloning efficiency is often still low. Here we have shown that pioglitazone, a selective peroxisome proliferative-activated receptor-? agonist, along with Y-27632 synergistically diminished dissociation-induced apoptosis and increased cloning efficiency (2-3-fold versus Y-27632) without affecting pluripotency of hPSCs. Pioglitazone exerted its positive effect by inhibition of glycogen synthase kinase (GSK3) activity and enhancement of membranous ?-catenin and E-cadherin proteins. These effects were reversed by GW-9662, an irreversible peroxisome proliferative-activated receptor-? antagonist. This novel setting provided a step toward hPSC manipulation and its biomedical applications. PMID:26336103

  2. Peroxisome biogenesis in mammalian cells.

    PubMed

    Fujiki, Yukio; Okumoto, Kanji; Mukai, Satoru; Honsho, Masanori; Tamura, Shigehiko

    2014-01-01

    To investigate peroxisome assembly and human peroxisome biogenesis disorders (PBDs) such as Zellweger syndrome, thirteen different complementation groups (CGs) of Chinese hamster ovary (CHO) cell mutants defective in peroxisome biogenesis have been isolated and established as a model research system. Successful gene-cloning studies by a forward genetic approach utilized a rapid functional complementation assay of CHO cell mutants led to isolation of human peroxin (PEX) genes. Search for pathogenic genes responsible for PBDs of all 14 CGs is now completed together with the homology search by screening the human expressed sequence tag database using yeast PEX genes. Peroxins are divided into three groups: (1) peroxins including Pex3p, Pex16p, and Pex19p, are responsible for peroxisome membrane biogenesis via classes I and II pathways; (2) peroxins that function in matrix protein import; (3) those such as three forms of Pex11p, Pex11p?, Pex11p?, and Pex11p?, are involved in peroxisome proliferation where DLP1, Mff, and Fis1 coordinately function. In membrane assembly, Pex19p forms complexes in the cytosol with newly synthesized PMPs including Pex16p and transports them to the receptor Pex3p, whereby peroxisomal membrane is formed (Class I pathway). Pex19p likewise forms a complex with newly made Pex3p and translocates it to the Pex3p receptor, Pex16p (Class II pathway). In matrix protein import, newly synthesized proteins harboring peroxisome targeting signal type 1 or 2 are recognized by Pex5p or Pex7p in the cytoplasm and are imported to peroxisomes via translocation machinery. In regard to peroxisome-cytoplasmic shuttling of Pex5p, Pex5p initially targets to an 800-kDa docking complex consisting of Pex14p and Pex13p and then translocates to a 500-kDa RING translocation complex. At the terminal step, Pex1p and Pex6p of the AAA family mediate the export of Pex5p, where Cys-ubiquitination of Pex5p is essential for the Pex5p exit. PMID:25177298

  3. Peroxisome biogenesis in mammalian cells

    PubMed Central

    Fujiki, Yukio; Okumoto, Kanji; Mukai, Satoru; Honsho, Masanori; Tamura, Shigehiko

    2014-01-01

    To investigate peroxisome assembly and human peroxisome biogenesis disorders (PBDs) such as Zellweger syndrome, thirteen different complementation groups (CGs) of Chinese hamster ovary (CHO) cell mutants defective in peroxisome biogenesis have been isolated and established as a model research system. Successful gene-cloning studies by a forward genetic approach utilized a rapid functional complementation assay of CHO cell mutants led to isolation of human peroxin (PEX) genes. Search for pathogenic genes responsible for PBDs of all 14 CGs is now completed together with the homology search by screening the human expressed sequence tag database using yeast PEX genes. Peroxins are divided into three groups: (1) peroxins including Pex3p, Pex16p, and Pex19p, are responsible for peroxisome membrane biogenesis via classes I and II pathways; (2) peroxins that function in matrix protein import; (3) those such as three forms of Pex11p, Pex11p?, Pex11p?, and Pex11p?, are involved in peroxisome proliferation where DLP1, Mff, and Fis1 coordinately function. In membrane assembly, Pex19p forms complexes in the cytosol with newly synthesized PMPs including Pex16p and transports them to the receptor Pex3p, whereby peroxisomal membrane is formed (Class I pathway). Pex19p likewise forms a complex with newly made Pex3p and translocates it to the Pex3p receptor, Pex16p (Class II pathway). In matrix protein import, newly synthesized proteins harboring peroxisome targeting signal type 1 or 2 are recognized by Pex5p or Pex7p in the cytoplasm and are imported to peroxisomes via translocation machinery. In regard to peroxisome-cytoplasmic shuttling of Pex5p, Pex5p initially targets to an 800-kDa docking complex consisting of Pex14p and Pex13p and then translocates to a 500-kDa RING translocation complex. At the terminal step, Pex1p and Pex6p of the AAA family mediate the export of Pex5p, where Cys-ubiquitination of Pex5p is essential for the Pex5p exit. PMID:25177298

  4. Peroxisome Proliferator-Activated Receptors as Mediators of Phthalate-Induced Effects in the Male and Female Reproductive Tract: Epidemiological and Experimental Evidence

    PubMed Central

    Latini, Giuseppe; Scoditti, Egeria; Verrotti, Alberto; De Felice, Claudio; Massaro, Marika

    2008-01-01

    There is growing evidence that male as well as female reproductive function has been declining in human and wildlife populations over the last 40 years. Several factors such as lifestyle or environmental xenobiotics other than genetic factors may play a role in determining adverse effects on reproductive health. Among the environmental xenobiotics phthalates, a family of man-made pollutants are suspected to interfere with the function of the endocrine system and therefore to be endocrine disruptors. The definition of endocrine disruption is today extended to broader endocrine regulations, and includes activation of metabolic sensors, such as the peroxisome proliferator-activated receptors (PPARs). Toxicological studies have shown that phthalates can activate a subset of PPARs. Here, we analyze the epidemiological and experimental evidence linking phthalate exposure to both PPAR activation and adverse effects on male and female reproductive health. PMID:18288285

  5. Dual-Action Inhibitors of HIF Prolyl Hydroxylases That Induce Binding of a Second Iron Ion

    PubMed Central

    Thalhammer, Armin; Demetriades, Marina; Chowdhury, Rasheduzzaman; Tian, Ya-Min; Stolze, Ineke; McNeill, Luke A.; Lee, Myung Kyu; Woon, Esther C. Y.; Mackeen, Mukram M.; Kawamura, Akane; Ratcliffe, Peter J.; Mecinovi?, Jasmin; Schofield, Christopher J.

    2015-01-01

    Inhibition of the hypoxia-inducible factor (HIF) prolyl-hydroxylases (PHD or EGLN enzymes) is of interest for the treatment of anemia and ischemia-related diseases. Most PHD inhibitors work by binding to the single ferrous ion and competing with 2-oxoglutarate (2OG) co-substrate for binding at the PHD active site. Non-specific iron chelators also inhibit the PHDs, both in vitro and in cells. We report the identification of dual action PHD inhibitors, which bind to the active site iron and also induce the binding of a second iron ion at the active site. Following analysis of small-molecule iron complexes and application of non-denaturing protein mass spectrometry to assess PHD2ironinhibitor stoichimetry, selected diacylhydrazines were identified as PHD2 inhibitors that induce the binding of a second iron ion. Some compounds were shown to inhibit the HIF hydroxylases in human hepatoma and renal carcinoma cell lines. PMID:23151668

  6. Resistance to BRAF inhibitors induces glutamine dependency in melanoma cells.

    PubMed

    Baenke, Franziska; Chaneton, Barbara; Smith, Matthew; Van Den Broek, Niels; Hogan, Kate; Tang, Haoran; Viros, Amaya; Martin, Matthew; Galbraith, Laura; Girotti, Maria R; Dhomen, Nathalie; Gottlieb, Eyal; Marais, Richard

    2016-01-01

    BRAF inhibitors can extend progression-free and overall survival in melanoma patients whose tumors harbor mutations in BRAF. However, the majority of patients eventually develop resistance to these drugs. Here we show that BRAF mutant melanoma cells that have developed acquired resistance to BRAF inhibitors display increased oxidative metabolism and increased dependency on mitochondria for survival. Intriguingly, the increased oxidative metabolism is associated with a switch from glucose to glutamine metabolism and an increased dependence on glutamine over glucose for proliferation. We show that the resistant cells are more sensitive to mitochondrial poisons and to inhibitors of glutaminolysis, suggesting that targeting specific metabolic pathways may offer exciting therapeutic opportunities to treat resistant tumors, or to delay emergence of resistance in the first-line setting. PMID:26365896

  7. Resistance to BRAF inhibitors induces glutamine dependency in melanoma cells

    PubMed Central

    Baenke, Franziska; Chaneton, Barbara; Smith, Matthew; Van Den Broek, Niels; Hogan, Kate; Tang, Haoran; Viros, Amaya; Martin, Matthew; Galbraith, Laura; Girotti, Maria R.; Dhomen, Nathalie; Gottlieb, Eyal; Marais, Richard

    2016-01-01

    BRAF inhibitors can extend progression-free and overall survival in melanoma patients whose tumors harbor mutations in BRAF. However, the majority of patients eventually develop resistance to these drugs. Here we show that BRAF mutant melanoma cells that have developed acquired resistance to BRAF inhibitors display increased oxidative metabolism and increased dependency on mitochondria for survival. Intriguingly, the increased oxidative metabolism is associated with a switch from glucose to glutamine metabolism and an increased dependence on glutamine over glucose for proliferation. We show that the resistant cells are more sensitive to mitochondrial poisons and to inhibitors of glutaminolysis, suggesting that targeting specific metabolic pathways may offer exciting therapeutic opportunities to treat resistant tumors, or to delay emergence of resistance in the first-line setting. PMID:26365896

  8. BET inhibitors induce apoptosis through a MYC independent mechanism and synergise with CDK inhibitors to kill osteosarcoma cells

    PubMed Central

    Baker, Emma K; Taylor, Scott; Gupte, Ankita; Sharp, Phillip P; Walia, Mannu; Walsh, Nicole C; Zannettino, Andrew CW; Chalk, Alistair M; Burns, Christopher J; Walkley, Carl R

    2015-01-01

    Osteosarcoma (OS) survival rates have plateaued in part due to a lack of new therapeutic options. Here we demonstrate that bromodomain inhibitors (BETi), JQ1, I-BET151, I-BET762, exert potent anti-tumour activity against primary and established OS cell lines, mediated by inhibition of BRD4. Strikingly, unlike previous observations in long-term established human OS cell lines, the antiproliferative activity of JQ1 in primary OS cells was driven by the induction of apoptosis, not cell cycle arrest. In further contrast, JQ1 activity in OS was mediated independently of MYC downregulation. We identified that JQ1 suppresses the transcription factor FOSL1 by displacement of BRD4 from its locus. Loss of FOSL1 phenocopied the antiproliferative effects of JQ1, identifying FOSL1 suppression as a potential novel therapeutic approach for OS. As a monotherapy JQ1 demonstrated significant anti-tumour activity in vivo in an OS graft model. Further, combinatorial treatment approaches showed that JQ1 increased the sensitivity of OS cells to doxorubicin and induced potent synergistic activity when rationally combined with CDK inhibitors. The greater level of activity achieved with the combination of BETi with CDK inhibitors demonstrates the efficacy of this combination therapy. Taken together, our studies show that BET inhibitors are a promising new therapeutic for OS. PMID:25944566

  9. Lovastatin, an inhibitor of cholesterol synthesis, induces hydroxymethylglutaryl-coenzyme A reductase directly on membranes of expanded smooth endoplasmic reticulum in rat hepatocytes.

    PubMed Central

    Singer, I I; Scott, S; Kazazis, D M; Huff, J W

    1988-01-01

    Lovastatin is a potent competitive inhibitor of the rate-limiting enzyme of cholesterol synthesis, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (NADPH) [HMG-CoA reductase; (S)-mevalonate:NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34]. We determined the subcellular distribution of HMG-CoA reductase at high resolution by means of immunoelectron microscopy on ultrathin frozen liver sections of rats treated with lovastatin and cholestyramine. High concentrations of reductase were located on the outer (cytoplasmic) surfaces of smooth endoplasmic reticulum (SER) membranes induced in hepatocytes by acute drug administration. The enzyme was specifically localized over the whorled SER membranes and was absent from nonwhorled SER, rough endoplasmic reticulum, and peroxisomes. Intense HMG-CoA reductase labeling was only observed in hepatocytes containing high levels of HMG-CoA reductase activity; no staining was detected in untreated livers. These observations show that HMG-CoA reductase is induced as an integral component of the SER membranes that form in rat hepatocytes subsequent to lovastatin treatment and suggest that the formation of SER whorls in rat hepatocytes is due to mechanism-based effects of lovastatin. Images PMID:3293052

  10. Lysine-specific demethylase 1 inhibitors protect cochlear spiral ganglion neurons against cisplatin-induced damage.

    PubMed

    Li, Ao; He, Yingzi; Sun, Shan; Cai, Chengfu; Li, Huawei

    2015-06-17

    Cisplatin is a widely used chemotherapeutic drug, but one of its side effects is ototoxicity. Epigenetic-related drugs, such as lysine-specific demethylase 1 (LSD1) inhibitors, have been reported to protect against cisplatin-induced hair cell loss by preventing demethylation of histone H3K4 (H3K4me2). However, the protective effect of LSD1 inhibitors in spiral ganglion neurons (SGNs) remains unclear. To investigate whether LSD1 inhibitors exert similar protective effects on SGNs, we treated mouse cochlear explant cultures with LSD1 inhibitors (2PCPA, S2101, or CBB1007) together with cisplatin. Low concentrations of cisplatin damaged SGNs much more than high concentrations, and blocking the demethylation of H3K4me2 with LSD1 inhibitors prevented the SGNs from injury. Reactive oxygen species are also involved in the injury process, and LSD1 inhibitors protected SGNs by increasing the expression level of the antioxidant gene Slc7a11 and decreasing the level of the pro-oxidant gene lactoperoxidase (Lpo). Our findings show that LSD1 inhibitors prevent cisplatin-induced SGN loss by regulating the demethylation of H3K4 and preventing increases of reactive oxygen species levels, which might provide a potential therapeutic strategy for cisplatin-induced hearing loss. PMID:26011390

  11. Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPAR?-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

    SciTech Connect

    Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa; Moon, Eun-Yi; Hong, Sung Hee

    2013-04-01

    Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)? ligand ciglitazone and novel PPAR? ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPAR? ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPAR? ligands and ?-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPAR? ligands induced cell death and ROS generation in a PPAR?-independent manner, enhanced ?-radiationinduced apoptosis and caspase-3mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPAR? ligand/?-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-? ligands may enhance the ?-radiation-induced DNA damage response, possibly by increasing ?-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPAR? ligands and ?-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.

  12. Peroxisome proliferator-activated receptor-gamma agonist 4-O-methylhonokiol induces apoptosis by triggering the intrinsic apoptosis pathway and inhibiting the PI3K/Akt survival pathway in SiHa human cervical cancer cells.

    PubMed

    Hyun, Seungyeon; Kim, Man Sub; Song, Yong Seok; Bak, Yesol; Ham, Sun Young; Lee, Dong Hun; Hong, Jintae; Yoon, Do Young

    2015-03-01

    4-O-Methylhonokiol (MH), a bioactive compound derived from Magnolia officinalis, is known to exhibit antitumor effects in various cancer cells. However, the precise mechanism of its anticancer activity in cervical cancer cells has not yet been studied. In this study, we demonstrated that MH induces apoptosis in SiHa cervical cancer cells by enhancing peroxisome proliferator-activated receptor-gamma (PPAR?) activation, followed by inhibition of the PI3K/Akt pathway and intrinsic pathway induction. MH upregulated PPAR? and PTEN expression levels while it decreased p-Akt in the MH-induced apoptotic process, thereby supporting the fact that MH is a PPAR? activator. Additionally, MH decreased the expression of Bcl-2 and Bcl-XL, inducing the intrinsic pathway in MH-treated SiHa cells. Furthermore, MH treatment led to the activation of caspase-3/caspase-9 and proteolytic cleavage of polyADP ribose polymerase. The expression levels of Fas (CD95) and E6/E7 oncogenes were not altered by MH treatment. Taken together, MH activates PPAR?/PTEN expression and induces apoptosis via suppression of the PI3K/Akt pathway and mitochondria-dependent pathways in SiHa cells. These findings suggest that MH has potential for development as a therapeutic agent for human cervical cancer. PMID:25563418

  13. Peroxisomes and sexual development in fungi

    PubMed Central

    Peraza-Reyes, Leonardo; Berteaux-Lecellier, Véronique

    2013-01-01

    Peroxisomes are versatile and dynamic organelles that are essential for the development of most eukaryotic organisms. In fungi, many developmental processes, such as sexual development, require the activity of peroxisomes. Sexual reproduction in fungi involves the formation of meiotic-derived sexual spores, often takes place inside multicellular fruiting bodies and requires precise coordination between the differentiation of multiple cell types and the progression of karyogamy and meiosis. Different peroxisomal functions contribute to the orchestration of this complex developmental process. Peroxisomes are required to sustain the formation of fruiting bodies and the maturation and germination of sexual spores. They facilitate the mobilization of reserve compounds via fatty acid β-oxidation and the glyoxylate cycle, allowing the generation of energy and biosynthetic precursors. Additionally, peroxisomes are implicated in the progression of meiotic development. During meiotic development in Podospora anserina, there is a precise modulation of peroxisome assembly and dynamics. This modulation includes changes in peroxisome size, number and localization, and involves a differential activity of the protein-machinery that drives the import of proteins into peroxisomes. Furthermore, karyogamy, entry into meiosis and sorting of meiotic-derived nuclei into sexual spores all require the activity of peroxisomes. These processes rely on different peroxisomal functions and likely depend on different pathways for peroxisome assembly. Indeed, emerging studies support the existence of distinct import channels for peroxisomal proteins that contribute to different developmental stages. PMID:24046747

  14. Peroxisomal ABC transporters: functions and mechanism.

    PubMed

    Baker, Alison; Carrier, David J; Schaedler, Theresia; Waterham, Hans R; van Roermund, Carlo W; Theodoulou, Frederica L

    2015-10-01

    Peroxisomes are arguably the most biochemically versatile of all eukaryotic organelles. Their metabolic functions vary between different organisms, between different tissue types of the same organism and even between different developmental stages or in response to changed environmental conditions. New functions for peroxisomes are still being discovered and their importance is underscored by the severe phenotypes that can arise as a result of peroxisome dysfunction. The β-oxidation pathway is central to peroxisomal metabolism, but the substrates processed are very diverse, reflecting the diversity of peroxisomes across species. Substrates for β-oxidation enter peroxisomes via ATP-binding cassette (ABC) transporters of subfamily D; (ABCD) and are activated by specific acyl CoA synthetases for further metabolism. Humans have three peroxisomal ABCD family members, which are half transporters that homodimerize and have distinct but partially overlapping substrate specificity; Saccharomyces cerevisiae has two half transporters that heterodimerize and plants have a single peroxisomal ABC transporter that is a fused heterodimer and which appears to be the single entry point into peroxisomes for a very wide variety of β-oxidation substrates. Our studies suggest that the Arabidopsis peroxisomal ABC transporter AtABCD1 accepts acyl CoA substrates, cleaves them before or during transport followed by reactivation by peroxisomal synthetases. We propose that this is a general mechanism to provide specificity to this class of transporters and by which amphipathic compounds are moved across peroxisome membranes. PMID:26517910

  15. Peroxisomal ABC transporters: functions and mechanism

    PubMed Central

    Baker, Alison; Carrier, David J.; Schaedler, Theresia; Waterham, Hans R.; van Roermund, Carlo W.; Theodoulou, Frederica L.

    2015-01-01

    Peroxisomes are arguably the most biochemically versatile of all eukaryotic organelles. Their metabolic functions vary between different organisms, between different tissue types of the same organism and even between different developmental stages or in response to changed environmental conditions. New functions for peroxisomes are still being discovered and their importance is underscored by the severe phenotypes that can arise as a result of peroxisome dysfunction. The β-oxidation pathway is central to peroxisomal metabolism, but the substrates processed are very diverse, reflecting the diversity of peroxisomes across species. Substrates for β-oxidation enter peroxisomes via ATP-binding cassette (ABC) transporters of subfamily D; (ABCD) and are activated by specific acyl CoA synthetases for further metabolism. Humans have three peroxisomal ABCD family members, which are half transporters that homodimerize and have distinct but partially overlapping substrate specificity; Saccharomyces cerevisiae has two half transporters that heterodimerize and plants have a single peroxisomal ABC transporter that is a fused heterodimer and which appears to be the single entry point into peroxisomes for a very wide variety of β-oxidation substrates. Our studies suggest that the Arabidopsis peroxisomal ABC transporter AtABCD1 accepts acyl CoA substrates, cleaves them before or during transport followed by reactivation by peroxisomal synthetases. We propose that this is a general mechanism to provide specificity to this class of transporters and by which amphipathic compounds are moved across peroxisome membranes. PMID:26517910

  16. Fis1, DLP1, and Pex11p coordinately regulate peroxisome morphogenesis

    SciTech Connect

    Kobayashi, Shinta; Tanaka, Atsushi; Fujiki, Yukio . E-mail: yfujiscb@mbox.nc.kyushu-u.ac.jp

    2007-05-01

    Dynamin-like protein 1 (DLP1) and Pex11p{beta} function in morphogenesis of peroxisomes. In the present work, we investigated whether Fis1 is involved in fission of peroxisomes. Endogenous Fis1 was morphologically detected in peroxisomes as well as mitochondria in wild-type CHO-K1 and DLP1-defective ZP121 cells. Subcellular fractionation studies also revealed the presence of Fis1 in peroxisomes. Peroxisomal Fis1 showed the same topology, i.e., C-tail anchored membrane protein, as the mitochondrial one. Furthermore, ectopic expression of FIS1 induced peroxisome proliferation in CHO-K1 cells, while the interference of FIS1 RNA resulted in tubulation of peroxisomes, hence reducing the number of peroxisomes. Fis1 interacted with Pex11p{beta}, by direct binding apparently involving the C-terminal region of Pex11p{beta} in the interaction. Pex11p{beta} also interacted with each other, whereas the binding of Pex11p{beta} to DLP1 was not detectable. Moreover, ternary complexes comprising Fis1, Pex11p{beta}, and DLP1 were detected by chemical cross-linking. We also showed that the highly conserved N-terminal domain of Pex11p{beta} was required for the homo-oligomerization of Pex11p{beta} and indispensable for the peroxisome-proliferating activity. Taken together, these findings indicate that Fis1 plays important roles in peroxisome division and maintenance of peroxisome morphology in mammalian cells, possibly in a concerted manner with Pex11p{beta} and DLP1.

  17. Histone deacetylase inhibitor trichostatin A and proteasome inhibitor PS-341 synergistically induce apoptosis in pancreatic cancer cells

    SciTech Connect

    Bai Jirong . E-mail: jbai@bidmc.harvard.edu; Demirjian, Aram; Sui Jianhua; Marasco, Wayne; Callery, Mark P. . E-mail: mcallery@bidmc.harvard.ede

    2006-10-06

    Pancreatic cancer is a common and lethal malignancy. Pancreatic cancer cells overexpress multiple anti-apoptotic factors and death receptor decoys, and are strongly resistant to radiation and to 5-fluorouracil (5-FU)- or gemcitabine (Gem)-based chemotherapy regimens. We have found that low-dose proteasome inhibitor PS-341 and histone deacetylase inhibitor trichostatin A (TSA) synergistically induce cytotoxicity in a panel of eight diverse pancreatic cancer cell lines. Combining TSA with PS-341 effectively inactivated NF{kappa}B signaling, downregulated the predominant endogenous anti-apoptotic factor Bcl-XL overexpression, and disrupted MAP kinase pathway. The combined drug regimen effectively inflicted an average of 71.5% apoptotic cell death (55.2-80%) in diverse pancreatic cancer cell lines by activating the intrinsic apoptotic pathway. Conclusion: the TSA/PS-341 regimen may represent a potential novel therapeutic strategy for pancreatic cancer.

  18. Elevation of cortical C26:0 due to the decline of peroxisomal β-oxidation potentiates amyloid β generation and spatial memory deficits via oxidative stress in diabetic rats.

    PubMed

    Shi, Y; Sun, X; Sun, Y; Hou, L; Yao, M; Lian, K; Li, J; Lu, X; Jiang, L

    2016-02-19

    Diabetes mellitus correlates with subsequent development of Alzheimer's disease (AD). An accumulation of very long chain fatty acids (VLCFAs) was observed in AD brains. We found previously that inhibiting peroxisomal β-oxidation by an inhibitor caused increases in VLCFA and β-amyloid peptide (Aβ) in the cortex and primary cultured neurons of rats. Therefore, we investigated whether there was an impaired peroxisomal β-oxidation and elevated VLCFA related to the increased Aβ in the diabetic brain. This study was conducted in a type 2 diabetic rat model induced by a high-fat diet and low-dose streptozotocin. A decrease in peroxisomal β-oxidation activity caused by down-regulated thiolase expression and a consequent increase in C26:0 were observed. Meanwhile, decreases in eicosapentenoic acid (EPA) and increases in oxidative stress [indicated by levels of malondialdehyde (MDA), and the protein expression of NOX4, p47(phox) and HO-1], Aβ, and the expression of AβPP and BACE1, two proteins involved in Aβ production, were observed. C26:0 levels were positively correlated with Aβ and MDA. This work suggests that in addition to decreases in EPA, increases in C26:0 by impaired peroxisomal β-oxidation can be a potential risk factor contributing to the progression of AD in diabetic brains via inducing oxidative stress. PMID:26687434

  19. The histone deacetylase inhibitor entinostat (SNDX-275) induces apoptosis in Hodgkin lymphoma cells and synergizes with Bcl-2 family inhibitors

    PubMed Central

    Jna, dm; Khaskhely, Noor; Buglio, Daniela; Shafer, Jessica A.; Derenzini, Enrico; Bollard, Catherine M.; Medeiros, L. Jeffrey; Ills, rpd; Ji, Yuan; Younes, Anas

    2011-01-01

    Objective Based on promising in vitro and in vivo activity of several histone deacetylase inhibitors (HDACis) in HL (Hodgkin lymphoma), we investigated SNDX-275, an oral class 1 isoformselective HDACi in HL-derived cell lines. Materials and Methods Proliferation and cell death were examined by MTS assay, Annexin-V/propidium iodide, and FACS analysis. Gene and protein expression were measured by RT-PCR, Western blotting, and immunohistochemical analysis. A multiplex assay was used to determine cytokines and chemokines. Results SNDX-275 induced cell death in a dose- and time-dependent manner with an IC50 at the sub- and lower micromolar range at 72 hours. At the molecular level, SNDX-275 increased histone H3 acetylation, up-regulated p21 expression, and activated the intrinsic apoptosis pathway by down-regulating the X-linked inhibitor of apoptosis protein (XIAP). SNDX-275 down-regulated the expression of antiapoptotic Bcl-2 and Bcl-xL proteins without altering Mcl-1 or Bax levels. Combination studies demonstrated that two Bcl-2 inhibitors (ABT-737 and obatoclax) significantly enhanced the effect of SNDX-275. SNDX-275 modulated the level of several cytokines and chemokines, including IL-12 p40-70, IP-10, RANTES, IL-13, IL-4, and TARC, and variably induced the cancer/testis antigen expression of MAGE-A4 and survivin in HL cell lines. Conclusions SNDX-275 has antiproliferative activity in HL cell lines, involving several mechanisms: induction of apoptosis, regulation of cytokines and chemokines, and alteration of CTAs. Clinical investigation of SNDX-275 alone or in combination with Bcl-2 inhibitors is warranted in patients with HL. Phase 2 studies with SNDX-275 in HL are ongoing, and future clinical studies should investigate combinations with SNDX-275. PMID:21767511

  20. 5-Lipoxygenase Inhibitors Attenuate TNF-?-Induced Inflammation in Human Synovial Fibroblasts

    PubMed Central

    Lin, Han-Ching; Lin, Tzu-Hung; Wu, Ming-Yueh; Chiu, Yung-Cheng; Tang, Chih-Hsin; Hour, Mann-Jen; Liou, Houng-Chi; Tu, Huang-Ju; Yang, Rong-Sen; Fu, Wen-Mei

    2014-01-01

    The lipoxygenase isoform of 5-lipoxygenase (5-LOX) is reported to be overexpressed in human rheumatoid arthritis synovial tissue and involved in the progress of inflammatory arthritis. However, the detailed mechanism of how 5-lipoxygenase regulates the inflammatory response in arthritis synovial tissue is still unclear. The aim of this study was to investigate the involvement of lipoxygenase pathways in TNF-?-induced production of cytokines and chemokines. Human synovial fibroblasts from rheumatoid patients were used in this study. 5-LOX inhibitors and shRNA were used to examine the involvement of 5-LOX in TNF-?-induced cytokines and chemokines expression. The signaling pathways were examined by Western Blotting or immunofluorescence staining. The effect of 5-LOX inhibitor on TNF-?-induced chemokine expression and paw edema was also explored in vivo in C57BL/6 mice. Treatment with 5-LOX inhibitors significantly decreased TNF-?-induced pro-inflammatory mediators including interleukin-6 (IL-6) and monocyte chemo-attractant protein-1 (MCP-1) in human synovial fibroblasts. Knockdown of 5-LOX using shRNA exerted similar inhibitory effects. The abrogation of NF-?B activation was involved in the antagonizing effects of these inhibitors. Furthermore, 5-LOX inhibitor decreased TNF-?-induced up-regulation of serum MCP-1 level and paw edema in mouse model. Our results provide the evidence that the administration of 5-LOX inhibitors is able to ameliorate TNF-?-induced cytokine/chemokine release and paw edema, indicating that 5-LOX inhibitors may be developed for therapeutic treatment of inflammatory arthritis. PMID:25229347

  1. Acyldepsipeptide HDAC inhibitor production induced in Burkholderia thailandensis

    PubMed Central

    Biggins, John B.; Gleber, Conrad D.; Brady, Sean F.

    2011-01-01

    Natural product gene clusters are often tightly regulated, resulting in gene cluster silencing in laboratory fermentation studies. The systematic overexpression of transcription factors (TFs) associated with biosynthetic gene clusters found in the genome of Burkholderia thailandensis E264 identified a set of TFs that, when overexpressed, alter the secondary metabolome of this bacterium. The isolation and characterization of burkholdacs A and B, two new acyldepsitripeptide histone deacetylase inhibitors produced by B. thailandensis overexpressing the TF bhcM is reported. PMID:21348454

  2. AMP-Activated Protein Kinase Interacts with the Peroxisome Proliferator-Activated Receptor Delta to Induce Genes Affecting Fatty Acid Oxidation in Human Macrophages

    PubMed Central

    Kemmerer, Marina; Finkernagel, Florian; Cavalcante, Marcela Frota; Abdalla, Dulcineia Saes Parra; Mller, Rolf; Brne, Bernhard; Namgaladze, Dmitry

    2015-01-01

    AMP-activated protein kinase (AMPK) maintains energy homeostasis by suppressing cellular ATP-consuming processes and activating catabolic, ATP-producing pathways such as fatty acid oxidation (FAO). The transcription factor peroxisome proliferator-activated receptor ? (PPAR?) also affects fatty acid metabolism, stimulating the expression of genes involved in FAO. To question the interplay of AMPK and PPAR? in human macrophages we transduced primary human macrophages with lentiviral particles encoding for the constitutively active AMPK?1 catalytic subunit, followed by microarray expression analysis after treatment with the PPAR? agonist GW501516. Microarray analysis showed that co-activation of AMPK and PPAR? increased expression of FAO genes, which were validated by quantitative PCR. Induction of these FAO-associated genes was also observed upon infecting macrophages with an adenovirus coding for AMPK?1 regulatory subunit carrying an activating R70Q mutation. The pharmacological AMPK activator A-769662 increased expression of several FAO genes in a PPAR?- and AMPK-dependent manner. Although GW501516 significantly increased FAO and reduced the triglyceride amount in very low density lipoproteins (VLDL)-loaded foam cells, AMPK activation failed to potentiate this effect, suggesting that increased expression of fatty acid catabolic genes alone may be not sufficient to prevent macrophage lipid overload. PMID:26098914

  3. Angiotensin-converting enzyme inhibitors-induced angioedema treated by C1 esterase inhibitor concentrate (Berinert): about one case and review of the therapeutic arsenal

    PubMed Central

    Lipski, Samuel Michael; Casimir, Georges; Vanlommel, Martine; Jeanmaire, Mathieu; Dolhen, Pierre

    2015-01-01

    Key Clinical Message C1 esterase inhibitor (Berinert) is generally used to treat severe attack of hereditary angioedema. We describe here the case of a patient who presented with a severe angioedema induced by angiotensin-converting enzyme inhibitors (ACEIs) endangering her life. It could be successfully treated with that medicine. PMID:25767713

  4. Angiotensin-converting enzyme inhibitors-induced angioedema treated by C1 esterase inhibitor concentrate (Berinert): about one case and review of the therapeutic arsenal.

    PubMed

    Lipski, Samuel Michael; Casimir, Georges; Vanlommel, Martine; Jeanmaire, Mathieu; Dolhen, Pierre

    2015-02-01

    C1 esterase inhibitor (Berinert) is generally used to treat severe attack of hereditary angioedema. We describe here the case of a patient who presented with a severe angioedema induced by angiotensin-converting enzyme inhibitors (ACEIs) endangering her life. It could be successfully treated with that medicine. PMID:25767713

  5. Proteasome inhibitors induce AMPK activation via CaMKK? in human breast cancer cells.

    PubMed

    Deshmukh, Rahul R; Dou, Q Ping

    2015-08-01

    The purpose of present study is to examine the mechanism of the 5'-AMP-activated protein kinase (AMPK) activation induced by proteasome inhibitors. AMPK activation and ubiquitin proteasome system (UPS) inhibition have gained great attention as therapeutic strategies for the treatment of certain types of cancers. While AMPK serves as a master regulator of cellular metabolism, UPS regulates protein homeostasis. However, the relationship between these two important pathways is not very clear. We observe that proteasome inhibition leads to AMPK activation in human breast cancer cells. siRNA transfection, western blotting, qPCR, and proteasomal inhibition assays were used to study the mechanism of proteasome inhibitor-induced AMPK activation using human triple-negative breast cancer, lung, and cervical cancer cell lines. We report that a variety of proteasome inhibitors activate AMPK in all the tested different cancer cell lines. Our data using liver kinase B1-deficient cancer cells suggest that proteasome inhibitor-induced AMPK activation is primarily mediated by Calcium/Calmodulin-dependent kinase kinase ? (CaMKK?). This hypothesis is supported by that pharmacological or genetic inhibition of CaMKK? leads to a decrease in proteasome inhibitor-induced AMPK activation. Additionally, the AMPK-activating function of the FDA-approved proteasome inhibitor bortezomib depends on an increase in intracellular calcium levels as calcium chelation abrogates its induced AMPK activation. Finally, bortezomib-mediated upregulation in CaMKK? levels is due to its enhanced protein synthesis. These data suggest that proteasome inhibitors indirectly activate AMPK in human cancer cells primarily via Ca(2+)-CaMKK?-dependent pathway. PMID:26227473

  6. Peroxisome assembly: matrix and membrane protein biogenesis.

    PubMed

    Ma, Changle; Agrawal, Gaurav; Subramani, Suresh

    2011-04-01

    The biogenesis of peroxisomal matrix and membrane proteins is substantially different from the biogenesis of proteins of other subcellular compartments, such as mitochondria and chloroplasts, that are of endosymbiotic origin. Proteins are targeted to the peroxisome matrix through interactions between specific targeting sequences and receptor proteins, followed by protein translocation across the peroxisomal membrane. Recent advances have shed light on the nature of the peroxisomal translocon in matrix protein import and the molecular mechanisms of receptor recycling. Furthermore, the endoplasmic reticulum has been shown to play an important role in peroxisomal membrane protein biogenesis. Defining the molecular events in peroxisome assembly may enhance our understanding of the etiology of human peroxisome biogenesis disorders. PMID:21464226

  7. Localization of peroxisomal matrix proteins by photobleaching

    SciTech Connect

    Buch, Charlotta; Soedertoerns University, Life Sciences, SE-141 89 Huddinge ; Hunt, Mary C.; Alexson, Stefan E.H.; Hallberg, Einar

    2009-10-16

    The distribution of some enzymes between peroxisomes and cytosol, or a dual localization in both these compartments, can be difficult to reconcile. We have used photobleaching in live cells expressing green fluorescent protein (GFP)-fusion proteins to show that imported bona fide peroxisomal matrix proteins are retained in the peroxisome. The high mobility of the GFP-fusion proteins in the cytosol and absence of peroxisomal escape makes it possible to eliminate the cytosolic fluorescence by photobleaching, to distinguish between exclusively cytosolic proteins and proteins that are also present at low levels in peroxisomes. Using this technique we found that GFP tagged bile acid-CoA:amino acid N-acyltransferase (BAAT) was exclusively localized in the cytosol in HeLa cells. We conclude that the cytosolic localization was due to its carboxyterminal non-consensus peroxisomal targeting signal (-SQL) since mutation of the -SQL to -SKL resulted in BAAT being efficiently imported into peroxisomes.

  8. UK114, a YjgF/Yer057p/UK114 family protein highly conserved from bacteria to mammals, is localized in rat liver peroxisomes

    SciTech Connect

    Antonenkov, Vasily D. . E-mail: vasily.antonenkov@oulu.fi; Ohlmeier, Steffen; Sormunen, Raija T.; Hiltunen, J. Kalervo

    2007-05-25

    Mammalian UK114 belongs to a highly conserved family of proteins with unknown functions. Although it is believed that UK114 is a cytosolic or mitochondrial protein there is no detailed study of its intracellular localization. Using analytical subcellular fractionation, electron microscopic colloidal gold technique, and two-dimensional gel electrophoresis of peroxisomal matrix proteins combined with mass spectrometric analysis we show here that a large portion of UK114 is present in rat liver peroxisomes. The peroxisomal UK114 is a soluble matrix protein and it is not inducible by the peroxisomal proliferator clofibrate. The data predict involvement of UK114 in peroxisomal metabolism.

  9. Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry

    PubMed Central

    McMillan, Kirk; Adler, Marc; Auld, Douglas S.; Baldwin, John J.; Blasko, Eric; Browne, Leslie J.; Chelsky, Daniel; Davey, David; Dolle, Ronald E.; Eagen, Keith A.; Erickson, Shawn; Feldman, Richard I.; Glaser, Charles B.; Mallari, Cornell; Morrissey, Michael M.; Ohlmeyer, Michael H. J.; Pan, Gonghua; Parkinson, John F.; Phillips, Gary B.; Polokoff, Mark A.; Sigal, Nolan H.; Vergona, Ronald; Whitlow, Marc; Young, Tish A.; Devlin, James J.

    2000-01-01

    Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC 1.14.13.39) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC50 values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (Kd ≈ 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor–heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein–protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED50 values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies. PMID:10677491

  10. Oxaliplatin Neurotoxicity Involves Peroxisome Alterations. PPAR? Agonism as Preventive Pharmacological Approach

    PubMed Central

    Zanardelli, Matteo; Micheli, Laura; Cinci, Lorenzo; Failli, Paola; Ghelardini, Carla; Di Cesare Mannelli, Lorenzo

    2014-01-01

    The development of neuropathic syndromes is an important, dose limiting side effect of anticancer agents like platinum derivates, taxanes and vinca alkaloids. The causes of neurotoxicity are still unclear but the impairment of the oxidative equilibrium is strictly related to pain. Two intracellular organelles, mitochondria and peroxisomes cooperate to the maintaining of the redox cellular state. Whereas a relationship between chemotherapy-dependent mitochondrial alteration and neuropathy has been established, the role of peroxisome is poor explored. In order to study the mechanisms of oxaliplatin-induced neurotoxicity, peroxisomal involvement was evaluated in vitro and in vivo. In primary rat astrocyte cell culture, oxaliplatin (10 M for 48 h or 1 M for 5 days) increased the number of peroxisomes, nevertheless expression and functionality of catalase, the most important antioxidant defense enzyme in mammalian peroxisomes, were significantly reduced. Five day incubation with the selective Peroxisome Proliferator Activated Receptor-? (PPAR-?) antagonist G3335 (30 M) induced a similar peroxisomal impairment suggesting a relationship between PPAR? signaling and oxaliplatin neurotoxicity. The PPAR? agonist rosiglitazone (10 M) reduced the harmful effects induced both by G3335 and oxaliplatin. In vivo, in a rat model of oxaliplatin induced neuropathy, a repeated treatment with rosiglitazone (3 and 10 mg kg?1 per os) significantly reduced neuropathic pain evoked by noxious (Paw pressure test) and non-noxious (Cold plate test) stimuli. The behavioral effect paralleled with the prevention of catalase impairment induced by oxaliplatin in dorsal root ganglia. In the spinal cord, catalase protection was showed by the lower rosiglitazone dosage without effect on the astrocyte density increase induced by oxaliplatin. Rosiglitazone did not alter the oxaliplatin-induced mortality of the human colon cancer cell line HT-29. These results highlight the role of peroxisomes in oxaliplatin-dependent nervous damage and suggest PPAR? stimulation as a candidate to counteract oxaliplatin neurotoxicity. PMID:25036594

  11. U-19451A: a selective inducible nitric oxide synthase inhibitor.

    PubMed

    Stratman, N C; Fici, G J; Sethy, V H

    1996-01-01

    Drugs with high selectivity for iNOS inhibition may be useful for treatment of neurodegenerative disorders, chronic inflammatory diseases, and septic shock. Therefore, U-19451A (2-benzyl-2-thio-pseudourea hydrochloride), a potential NOS inhibitor, has been investigated for its selectivity for iNOS using tissues, primary cerebellar granule cell cultures and glial cell cultures. Lungs isolated from rats treated with intravenous injection of E coli lipopolysaccharide and glial cell cultures treated with the same bacterial toxin plus gamma-interferon were used for iNOS activity. Rat cerebellum and primary cerebellar granule cell cultures were utilized for neuronal NOS (nNOS) activity. S-methylthiourea (SMT) and L-nitroarginine methyl ester (L-NAME), selective iNOS and nNOS inhibitors, respectively, were chosen as standards. Both U-19451A and SMT were 4-times more selective for iNOS as compared to nNOS in tissues. U-19451A was more selective than SMT for iNOS inhibition using cultures. L-NAME was 16-31 times more selective for inhibiting nNOS activity. Based on the selectivity of U-19451A for iNOS inhibition, this drug would be expected to be effective in the treatment of diseases with inflammatory pathology without producing side effects associated with nNOS inhibition. PMID:8795706

  12. Peroxisome proliferator-activated receptor-gamma co-activator 1alpha-mediated metabolic remodeling of skeletal myocytes mimics exercise training and reverses lipid-induced mitochondrial inefficiency.

    PubMed

    Koves, Timothy R; Li, Ping; An, Jie; Akimoto, Takayuki; Slentz, Dorothy; Ilkayeva, Olga; Dohm, G Lynis; Yan, Zhen; Newgard, Christopher B; Muoio, Deborah M

    2005-09-30

    Peroxisome proliferator-activated receptor-gamma co-activator 1alpha (PGC1alpha) is a promiscuous co-activator that plays a key role in regulating mitochondrial biogenesis and fuel homeostasis. Emergent evidence links decreased skeletal muscle PGC1alpha activity and coincident impairments in mitochondrial performance to the development of insulin resistance in humans. Here we used rodent models to demonstrate that muscle mitochondrial efficiency is compromised by diet-induced obesity and is subsequently rescued by exercise training. Chronic high fat feeding caused accelerated rates of incomplete fatty acid oxidation and accumulation of beta-oxidative intermediates. The capacity of muscle mitochondria to fully oxidize a heavy influx of fatty acid depended on factors such as fiber type and exercise training and was positively correlated with expression levels of PGC1alpha. Likewise, an efficient lipid-induced substrate switch in cultured myocytes depended on adenovirus-mediated increases in PGC1alpha expression. Our results supported a novel paradigm in which a high lipid supply, occurring under conditions of low PGC1alpha, provokes a disconnect between mitochondrial beta-oxidation and tricarboxylic acid cycle activity. Conversely, the metabolic remodeling that occurred in response to PGC1alpha overexpression favored a shift from incomplete to complete beta-oxidation. We proposed that PGC1alpha enables muscle mitochondria to better cope with a high lipid load, possibly reflecting a fundamental metabolic benefit of exercise training. PMID:16079133

  13. Xenobiotic-Induced Hepatocyte Proliferation Associated with Constitutive Active/Androstane Receptor (CAR) or Peroxisome Proliferator-Activated Receptor ? (PPAR?) Is Enhanced by Pregnane X Receptor (PXR) Activation in Mice

    PubMed Central

    Numakura, Yuki; Kodama, Susumu; Miyata, Masaaki; Yamazoe, Yasushi; Yoshinari, Kouichi

    2013-01-01

    Xenobiotic-responsive nuclear receptors pregnane X receptor (PXR), constitutive active/androstane receptor (CAR) and peroxisome proliferator-activated receptor ? (PPAR?) play pivotal roles in the metabolic functions of the liver such as xenobiotics detoxification and energy metabolism. While CAR or PPAR? activation induces hepatocyte proliferation and hepatocarcinogenesis in rodent models, it remains unclear whether PXR activation also shows such effects. In the present study, we have investigated the role of PXR in the xenobiotic-induced hepatocyte proliferation with or without CAR activation by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) and phenobarbital, or PPAR? activation by Wy-14643 in mice. Treatment with TCPOBOP or phenobarbital increased the percentage of Ki-67-positive nuclei as well as mRNA levels of cell proliferation-related genes in livers as expected. On the other hand, treatment with the PXR activator pregnenolone 16?-carbonitrile (PCN) alone showed no such effects. Surprisingly, PCN co-treatment significantly augmented the hepatocyte proliferation induced by CAR activation with TCPOBOP or phenobarbital in wild-type mice but not in PXR-deficient mice. Intriguingly, PXR activation also augmented the hepatocyte proliferation induced by Wy-14643 treatment. Moreover, PCN treatment increased the RNA content of hepatocytes, suggesting the induction of G0/G1 transition, and reduced mRNA levels of Cdkn1b and Rbl2, encoding suppressors of cell cycle initiation. Our present findings indicate that xenobiotic-induced hepatocyte proliferation mediated by CAR or PPAR? is enhanced by PXR co-activation despite that PXR activation alone does not cause the cell proliferation in mouse livers. Thus PXR may play a novel and unique role in the hepatocyte/liver hyperplasia upon exposure to xenobiotics. PMID:23626729

  14. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization.

    PubMed

    Meng, Zhen; Gan, Ye-Hua

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. PMID:25770423

  15. Determination of antithrombin-dependent factor Xa inhibitors by prothrombin-induced clotting time.

    PubMed

    Harenberg, Job; Giese, Christina; Hagedorn, Antje; Traeger, Inge; Fenyvesi, Tivadar

    2007-07-01

    Prothrombinase-induced clotting time (PiCT) determines the anticoagulant effects of heparins, low molecular weight heparins (LMWHs), and direct thrombin inhibitors. At present, this is the only method that measures the effects of all of these inhibitors, in contrast to the prothrombin time, activated partial thromboplastin time (aPTT), Heptest, ecarin clotting time, and the chromogenic assays. The antithrombin-dependent direct factor (F) Xa inhibitors fondaparinux and idraparinux were compared with the LMWH dalteparin on PiCT, aPTT, Heptest, and chromogenic anti-FXa assays in pooled human normal plasma samples. Fondaparinux and idraparinux prolonged the coagulation times in the PiCT, Heptest, and chromogenic FXa assays in a dose-dependent manner, in contrast to the aPTT. We conclude that PiCT is a suitable assay to determine the anticoagulant effects of these two new FXa inhibitors in patients receiving treatment with these compounds. PMID:17629847

  16. PeroxisomeDB 2.0: an integrative view of the global peroxisomal metabolome

    PubMed Central

    Schlter, Agatha; Real-Chicharro, Alejandro; Gabaldn, Toni; Snchez-Jimnez, Francisca; Pujol, Aurora

    2010-01-01

    Peroxisomes are essential organelles that play a key role in redox signalling and lipid homeostasis. They contain a highly diverse enzymatic network among different species, mirroring the varied metabolic needs of the organisms. The previous PeroxisomeDB version organized the peroxisomal proteome of humans and Saccharomyces cerevisiae based on genetic and functional information into metabolic categories with a special focus on peroxisomal disease. The new release (http://www.peroxisomeDB.org) adds peroxisomal proteins from 35 newly sequenced eukaryotic genomes including fungi, yeasts, plants and lower eukaryotes. We searched these genomes for a core ensemble of 139 peroxisomal protein families and identified 2706 putative peroxisomal protein homologs. Approximately 37% of the identified homologs contained putative peroxisome targeting signals (PTS). To help develop understanding of the evolutionary relationships among peroxisomal proteins, the new database includes phylogenetic trees for 2386 of the peroxisomal proteins. Additional new features are provided, such as a tool to capture kinetic information from Brenda, CheBI and Sabio-RK databases and more than 1400 selected bibliographic references. PeroxisomeDB 2.0 is a freely available, highly interactive functional genomics platform that offers an extensive view on the peroxisomal metabolome across lineages, thus facilitating comparative genomics and systems analysis of the organelle. PMID:19892824

  17. PeroxisomeDB: a database for the peroxisomal proteome, functional genomics and disease

    PubMed Central

    Schlter, Agatha; Fourcade, Stphane; Domnech-Estvez, Enric; Gabaldn, Toni; Huerta-Cepas, Jaime; Berthommier, Guillaume; Ripp, Raymond; Wanders, Ronald J. A.; Poch, Olivier; Pujol, Aurora

    2007-01-01

    Peroxisomes are essential organelles of eukaryotic origin, ubiquitously distributed in cells and organisms, playing key roles in lipid and antioxidant metabolism. Loss or malfunction of peroxisomes causes more than 20 fatal inherited conditions. We have created a peroxisomal database () that includes the complete peroxisomal proteome of Homo sapiens and Saccharomyces cerevisiae, by gathering, updating and integrating the available genetic and functional information on peroxisomal genes. PeroxisomeDB is structured in interrelated sections Genes, Functions, Metabolic pathways and Diseases, that include hyperlinks to selected features of NCBI, ENSEMBL and UCSC databases. We have designed graphical depictions of the main peroxisomal metabolic routes and have included updated flow charts for diagnosis. Precomputed BLAST, PSI-BLAST, multiple sequence alignment (MUSCLE) and phylogenetic trees are provided to assist in direct multispecies comparison to study evolutionary conserved functions and pathways. Highlights of the PeroxisomeDB include new tools developed for facilitating (i) identification of novel peroxisomal proteins, by means of identifying proteins carrying peroxisome targeting signal (PTS) motifs, (ii) detection of peroxisomes in silico, particularly useful for screening the deluge of newly sequenced genomes. PeroxisomeDB should contribute to the systematic characterization of the peroxisomal proteome and facilitate system biology approaches on the organelle. PMID:17135190

  18. Peroxisomal disorders with infantile seizures.

    PubMed

    Liang, Jao-Shwann; Lu, Jyh-Feng

    2011-10-01

    Peroxisomes are organelles responsible for multiple metabolic pathways including the biosynthesis of plasmalogens and the oxidation of branched-chain as well as very-long-chain fatty acids (VLCFAs). Peroxisomal disorders (PDs) are heterogeneous groups of diseases and affect many organs with varying degrees of involvement. Even pathogenetically distinct PDs share some common symptoms. However, several PDs have uniquely characteristic clinical findings. The durations of survival in PDs are also variable. Infants with PDs are usually presented with developmental delay, visual and hearing impairment. Generalized hypotonia is present in severe cases. Epileptic seizures are also a common characteristic of patients with certain PDs. Nonetheless, the classification and evolution of epilepsy in PDs have not been elucidated in detail. Here, we review the relevant literatures and provide an overview of PDs with particular emphasis on the characteristics of seizures in infants. PMID:21397417

  19. Peroxisomes in Different Skeletal Cell Types during Intramembranous and Endochondral Ossification and Their Regulation during Osteoblast Differentiation by Distinct Peroxisome Proliferator-Activated Receptors

    PubMed Central

    Qian, Guofeng; Karnati, Srikanth; Baumgart-Vogt, Eveline

    2015-01-01

    Ossification defects leading to craniofacial dysmorphism or rhizomelia are typical phenotypes in patients and corresponding knockout mouse models with distinct peroxisomal disorders. Despite these obvious skeletal pathologies, to date no careful analysis exists on the distribution and function of peroxisomes in skeletal tissues and their alterations during ossification. Therefore, we analyzed the peroxisomal compartment in different cell types of mouse cartilage and bone as well as in primary cultures of calvarial osteoblasts. The peroxisome number and metabolism strongly increased in chondrocytes during endochondral ossification from the reserve to the hypertrophic zone, whereas in bone, metabolically active osteoblasts contained a higher numerical abundance of this organelle than osteocytes. The high abundance of peroxisomes in these skeletal cell types is reflected by high levels of Pex11β gene expression. During culture, calvarial pre-osteoblasts differentiated into secretory osteoblasts accompanied by peroxisome proliferation and increased levels of peroxisomal genes and proteins. Since many peroxisomal genes contain a PPAR-responsive element, we analyzed the gene expression of PPARɑ/ß/ɣ in calvarial osteoblasts and MC3T3-E1 cells, revealing higher levels for PPARß than for PPARɑ and PPARɣ. Treatment with different PPAR agonists and antagonists not only changed the peroxisomal compartment and associated gene expression, but also induced complex alterations of the gene expression patterns of the other PPAR family members. Studies in M3CT3-E1 cells showed that the PPARß agonist GW0742 activated the PPRE-mediated luciferase expression and up-regulated peroxisomal gene transcription (Pex11, Pex13, Pex14, Acox1 and Cat), whereas the PPARß antagonist GSK0660 led to repression of the PPRE and a decrease of the corresponding mRNA levels. In the same way, treatment of calvarial osteoblasts with GW0742 increased in peroxisome number and related gene expression and accelerated osteoblast differentiation. Taken together, our results suggest that PPARß regulates the numerical abundance and metabolic function of peroxisomes via Pex11ß in parallel to osteoblast differentiation. PMID:26630504

  20. Shikonin, dually functions as a proteasome inhibitor and a necroptosis inducer in multiple myeloma cells

    PubMed Central

    WADA, NAOKO; KAWANO, YAWARA; FUJIWARA, SHIHO; KIKUKAWA, YOSHITAKA; OKUNO, YUTAKA; TASAKI, MASAYOSHI; UEDA, MITSUHARU; ANDO, YUKIO; YOSHINAGA, KAZUYA; RI, MASAKI; IIDA, SHINSUKE; NAKASHIMA, TAKAYUKI; SHIOTSU, YUKIMASA; MITSUYA, HIROAKI; HATA, HIROYUKI

    2015-01-01

    Shikonin (SHK), a natural small agent (MW 288.3), reportedly induces cell death in various tumor cells. We have found that SHK also exerts potent cytocidal effects on human multiple myeloma (MM) cells, but its anticancer mechanism in MM cells remains to be elucidated. SHK at 2.5–5 μM induced apoptosis in seven MM cell lines, including the bortezomib-resistant cell line KMS11/BTZ. The IC50 value of SHK against KMS11/BTZ was comparable to that of a parental cell line KMS11 (1.1 and 1.56 μM, respectively). SHK induces accumulation of ubiquitinated proteins and activates XBP-1 in MM cells, suggesting that SHK functions as a proteasome inhibitor, eventually inducing ER stress-associated apoptosis. SHK increases levels of HSP70/72, which protects cells from apoptosis, and exerts greater cytocidal effects in combination with the HSP70/72 inhibitor VER-155008. At higher concentrations (10–20 μM), SHK induced cell death, which was completely inhibited by a necroptosis inhibitor, necrostatin-1 (Nec-1), while the cytocidal activity was unaffected by Z-VAD-FMK, strongly suggesting that cell death is induced by SHK at high concentrations through necroptosis. The present data show for the first time that SHK induces cell death in MM cells. SHK efficiently induces apoptosis and combination of heat shock protein inhibitor with low dose SHK enhances apoptosis, while high dose SHK induces necroptosis in MM cells. These findings together support the use of SHK as a potential therapeutic agent for MM. PMID:25530098

  1. Quinazolines as Apoptosis Inducers and Inhibitors: A Review of Patent Literature.

    PubMed

    Mehndiratta, Samir; Sapra, Sameer; Singh, Gurpreet; Singh, Manwinder; Nepali, Kunal

    2016-01-01

    Quinazoline scaffold has been successfully utilized for development of various inhibitors of tubulin, epidermal growth factor receptor (EGFR), polo like kinases (PLKs), Hedgehog-Gli signaling pathway and protein kinase B (PKB) /Akt pathway. Compounds based on quinazolines have shown efficacies in M to nM range in various cancer cell lines and thus could be useful scaffolds for development of both apoptosis inducers as well as inhibitors. This compilation is based on various patents published till 2015 and divides the quinazolines in two main categories: Quinazolines as apoptosis inducers and as apoptosis inhibitors. These two main categories are further sub-categorized based on the use/pharmacological indications for these classes of patented compounds. This review will act as a tool for the researchers working on exploring the anticancer potential of quinazoline as a privileged heterocyclic. The promising anticancer profile of some of the quinazoline based compounds clearly highlights the clinical potential of this heterocycle. PMID:26681186

  2. Import of proteins into the peroxisomal matrix

    PubMed Central

    Hasan, Sohel; Platta, Harald W.; Erdmann, Ralf

    2013-01-01

    Peroxisomes constitute a dynamic compartment in all nucleated cells. They fulfill diverse metabolic tasks in response to environmental changes and cellular demands. This adaptation is implemented by modulation of the enzyme content of the organelles, which is accomplished by dynamically operating peroxisomal protein transport machineries. Soluble import receptors recognize their newly synthesized cargo proteins in the cytosol and ferry them to the peroxisomal membrane. Subsequently, the cargo is translocated into the matrix, where the receptor is ubiquitinated and exported back to the cytosol for further rounds of matrix protein import. This review discusses the recent progress in our understanding of the peroxisomal matrix protein import and its regulation by ubiquitination events as well as the current view on the translocation mechanism of folded proteins into peroxisomes. This article is part of a Special Issue entitled: Origin and spatiotemporal dynamics of the peroxisomal endomembrane system. PMID:24069002

  3. Insect and wound induced GUS gene expression from a Beta vulgaris proteinase inhibitor gene promoter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inducible gene promoters that are specifically activated by pathogen invasion or insect pest attack are needed for effective expression of resistance genes to control plant diseases. In the present study, a promoter from a serine proteinase inhibitor gene (BvSTI) shown to be up-regulated in resist...

  4. MAP KINASE ERK 1/2 INHIBITORS INDUCE DYSMORPHOLOGY IN MOUSE WHOLE EMBRYO CULTURE

    EPA Science Inventory

    ROSEN, M.B. and E. S. HUNTER. Reproductive Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina. MAP kinase Erk1/2 inhibitors induce dysmorphology in mouse whole embryo culture.

    MAP Kinase signal transduction is associated with a variety ...

  5. Proteasome inhibitors induce apoptosis and reduce viral replication in primary effusion lymphoma cells

    SciTech Connect

    Saji, Chiaki; Higashi, Chizuka; Niinaka, Yasufumi; Yamada, Koji; Noguchi, Kohji; Fujimuro, Masahiro

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Constitutive NF-{kappa}B signaling is essential for the survival and growth of PEL cells. Black-Right-Pointing-Pointer NF-{kappa}B signaling is upregulated by the proteasome-dependent degradation of I{kappa}B{alpha}. Black-Right-Pointing-Pointer Proteasome inhibitors suppress NF-{kappa}B signaling and induce apoptosis in PEL cells through stabilization of I{kappa}B{alpha}. Black-Right-Pointing-Pointer Proteasome inhibitors suppress viral replication in PEL cells during lytic KSHV infection. -- Abstract: Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi's sarcoma-associated herpesvirus (KSHV). This study provides evidence that proteasomal activity is required for both survival of PEL cells stably harboring the KSHV genome and viral replication of KSHV. We evaluated the cytotoxic effects of proteasome inhibitors on PEL cells. The proteasome inhibitors MG132, lactacystin, and proteasome inhibitor I dramatically inhibited cell proliferation and induced apoptosis of PEL cells through the accumulation of p21 and p27. Furthermore, proteasome inhibitors induced the stabilization of NF-{kappa}B inhibitory molecule (I{kappa}B{alpha}) and suppressed the transcriptional activity of NF-{kappa}B in PEL cells. The NF-{kappa}B specific inhibitor BAY11-7082 also induced apoptosis in PEL cells. The constitutive activation of NF-{kappa}B signaling is essential for the survival and growth of B cell lymphoma cells, including PEL cells. NF-{kappa}B signaling is upregulated by proteasome-dependent degradation of I{kappa}B{alpha}. The suppression of NF-{kappa}B signaling by proteasome inhibitors may contribute to the induction of apoptosis in PEL cells. In addition, proteasome activity is required for KSHV replication in KSHV latently infected PEL cells. MG132 reduced the production of progeny virus from PEL cells at low concentrations, which do not affect PEL cell growth. These findings suggest that proteasome inhibitors may represent a novel strategy for the treatment of KSHV infection and KSHV-associated lymphomas.

  6. An aqueous extract of Salacia oblonga root, a herb-derived peroxisome proliferator-activated receptor-alpha activator, by oral gavage over 28 days induces gender-dependent hepatic hypertrophy in rats.

    PubMed

    Rong, Xianglu; Kim, Moon Sun; Su, Ning; Wen, Suping; Matsuo, Yukimi; Yamahara, Johji; Murray, Michael; Li, Yuhao

    2008-06-01

    Activation of peroxisome proliferator-activated receptor (PPAR)-alpha by natural and synthetic chemicals induces hepatic hypertrophy. An aqueous extract of Salacia oblonga root (SOW) is an Ayurvedic medicine with anti-diabetic and anti-obesity properties. In the present study, it was found that SOW (100, 300 and 900mg/kg, once daily by oral gavage over a 28 day period) elicited dose-related increases in liver weight (LW) by 1.6%, 13.4% and 42.5%, respectively, and in the ratio of LW to body weight by 8.8%, 16.7% and 40.2%, respectively, in male rats. These effects were less pronounced in females. SOW selectively increased liver mass in male rats but Sudan red staining was not different, which indicates that hepatic lipid accumulation was similar in both genders. However, SOW even at the highest dosage did not influence serum ALT and AST activities in male or female rats. Moreover, SOW was found to activate PPAR-alpha in human hepatoma-derived HepG2 cells, as evidenced by the upregulation of PPAR-alpha and acyl-CoA oxidase mRNA expression. Thus, SOW-dependent PPAR-alpha activation may precede the development of the gender difference in hepatic hypertrophy; this process may be influenced by sex hormone status. PMID:18397819

  7. Peroxisome proliferator-activated receptor ? downregulates the expression of the receptor for advanced glycation end products and pro-inflammatory cytokines in the kidney of streptozotocin-induced diabetic mice.

    PubMed

    Liang, Yao-Jen; Chen, Siang-An; Jian, Jhih-Hao

    2011-05-18

    Activation of peroxisome proliferator-activated receptor ? (PPAR?) plays board beneficial effects in treating metabolic syndrome. The aim of this study is to examine whether PPAR? alters the expression of the receptor for advanced glycation end products (RAGE) and downstream pro-inflammatory cytokines in diabetic nephropathy. Streptozotocin-induced diabetic mice (STZ mice) were injected with a PPAR? agonist, L-165041 (5 ?M/kg, intraperitoneal) once daily for 10 days and high glucose-treated cultured HEK cells were also used. After L-165041 treatment, serum TNF?, IL-6 and IL-1 levels were significantly decreased in STZ mice. RAGE mRNA and protein expression were both decreased by L-165041 in kidney tissues of STZ mice. The high glucose incubation increased NF-?B, RAGE and IL-6 expressions in HEK293 cells. These effects were inhibited by L-165041 and specific RAGE siRNA transfection. This study demonstrated that PPAR? may play a beneficial role in preventing diabetic nephropathy. Its downstream signaling may include RAGE and NF-?B pathway. Target on PPAR? will provide new meaningful therapies to patients with diabetic nephropathy. PMID:21458563

  8. Localization of a portion of the liver isoform of fatty-acid-binding protein (L-FABP) to peroxisomes

    PubMed Central

    Antonenkov, VasilyD.; Sormunen, RaijaT.; Ohlmeier, Steffen; Amery, Leen; Fransen, Marc; Mannaerts, GuyP.; Hiltunen, J.Kalervo

    2005-01-01

    The liver isoform of fatty-acid-binding protein (L-FABP) facilitates the cellular uptake, transport and metabolism of fatty acids and is also involved in the regulation of gene expressions and cell differentiation. Consistent with these functions, L-FABP is predominantly present in the cytoplasm and to a lesser extent in the nucleus; however, a significant portion of this protein has also been detected in fractions containing different organelles. More recent observations, notably on L-FABP-deficient mice, indicated a possible direct involvement of L-FABP in the peroxisomal oxidation of long-chain fatty acids. In order to clarify the links between L-FABP and peroxisomal lipid metabolism, we reinvestigated the subcellular distribution of the protein. Analytical subcellular fractionation by a method preserving the intactness of isolated peroxisomes, two-dimensional gel electrophoresis of peroxisomal matrix proteins combined with MS analysis, and immunoelectron microscopy of liver sections demonstrate the presence of L-FABP in the matrix of peroxisomes as a soluble protein. Peroxisomal L-FABP was highly inducible by clofibrate. The induction of L-FABP was accompanied by a marked increase in the binding capacity of peroxisomal matrix proteins for oleic acid and cis-parinaric acid. The peroxisomal ?-oxidation of palmitoyl-CoA and acyl-CoA thioesterase activity were stimulated by L-FABP, indicating that the protein modulates the function of peroxisomal lipid-metabolizing enzymes. The possible role of intraperoxisomal L-FABP in lipid metabolism is discussed. PMID:16262600

  9. Amelioration of cyclosporine induced nephrotoxicity by dipeptidyl peptidase inhibitor vildagliptin.

    PubMed

    Ateyya, Hayam

    2015-09-01

    Cyclosporine A (CsA) is an immunosuppressive drug used in organ transplantation and autoimmune diseases but its clinical uses may be limited due to its dose-related nephrotoxicity. This study was carried out to evaluate the possible protective effects of vildagliptin (VLD) against CsA-induced nephrotoxicity in rats. Animals were divided into four groups treated as follows: control group (CsA & VLD vehicle); VLD group (10mg/kg/day, orally); CsA group (20mg/kg in sunflower oil, S.C.); and CsA-VLD group (CsA &VLD). Induced nephrotoxicity was evidenced by a significant elevation of serum creatinine, blood urea nitrogen (BUN), lactate dehydrogenase (LDH) and urinary micro total proteins (MTP), while serum albumin and urinary creatinine clearance were significantly decreased compared to the control group. Moreover, renal dysfunction was further confirmed by a significant increase in renal lipid peroxide that was measured as renal malondialdehyde (MDA). Renal reduced glutathione (GSH) and superoxide dismutase (SOD) were significantly decreased. Nephrotoxicity was further confirmed by renal tissue histopathology. Also, a high protein expression of Bax with decreased Bcl-2 was revealed in the renal tissue of the CsA treated group. Administration of VLD significantly ameliorated the nephrotoxic effects of CsA suggesting antioxidant, anti-inflammatory and anti-apoptotic benefits of VLD in CsA-induced nephrotoxicity. PMID:26225924

  10. Combining BET and HDAC inhibitors synergistically induces apoptosis of melanoma and suppresses AKT and YAP signaling

    PubMed Central

    Heinemann, Anja; Cullinane, Carleen; De Paoli-Iseppi, Ricardo; Wilmott, James S.; Gunatilake, Dilini; Madore, Jason; Strbenac, Dario; Yang, Jean Y.; Gowrishankar, Kavitha; Tiffen, Jessamy C.; Prinjha, Rab K.; Smithers, Nicholas; McArthur, Grant A.; Hersey, Peter; Gallagher, Stuart J.

    2015-01-01

    Histone acetylation marks have an important role in controlling gene expression and are removed by histone deacetylases (HDACs). These marks are read by bromodomain and extra-terminal (BET) proteins and novel inhibitiors of these proteins are currently in clinical development. Inhibitors of HDAC and BET proteins have individually been shown to cause apoptosis and reduce growth of melanoma cells. Here we show that combining the HDAC inhibitor LBH589 and BET inhibitor I-BET151 synergistically induce apoptosis of melanoma cells but not of melanocytes. Induction of apoptosis proceeded through the mitochondrial pathway, was caspase dependent and involved upregulation of the BH3 pro-apoptotic protein BIM. Analysis of signal pathways in melanoma cell lines resistant to BRAF inhibitors revealed that treatment with the combination strongly downregulated anti-apoptotic proteins and proteins in the AKT and Hippo/YAP signaling pathways. Xenograft studies showed that the combination of inhibitors was more effective than single drug treatment and confirmed upregulation of BIM and downregulation of XIAP as seen in vitro. These results support the combination of these two classes of epigenetic regulators in treatment of melanoma including those resistant to BRAF inhibitors. PMID:26087189

  11. Combining BET and HDAC inhibitors synergistically induces apoptosis of melanoma and suppresses AKT and YAP signaling.

    PubMed

    Heinemann, Anja; Cullinane, Carleen; De Paoli-Iseppi, Ricardo; Wilmott, James S; Gunatilake, Dilini; Madore, Jason; Strbenac, Dario; Yang, Jean Y; Gowrishankar, Kavitha; Tiffen, Jessamy C; Prinjha, Rab K; Smithers, Nicholas; McArthur, Grant A; Hersey, Peter; Gallagher, Stuart J

    2015-08-28

    Histone acetylation marks have an important role in controlling gene expression and are removed by histone deacetylases (HDACs). These marks are read by bromodomain and extra-terminal (BET) proteins and novel inhibitiors of these proteins are currently in clinical development. Inhibitors of HDAC and BET proteins have individually been shown to cause apoptosis and reduce growth of melanoma cells. Here we show that combining the HDAC inhibitor LBH589 and BET inhibitor I-BET151 synergistically induce apoptosis of melanoma cells but not of melanocytes. Induction of apoptosis proceeded through the mitochondrial pathway, was caspase dependent and involved upregulation of the BH3 pro-apoptotic protein BIM. Analysis of signal pathways in melanoma cell lines resistant to BRAF inhibitors revealed that treatment with the combination strongly downregulated anti-apoptotic proteins and proteins in the AKT and Hippo/YAP signaling pathways. Xenograft studies showed that the combination of inhibitors was more effective than single drug treatment and confirmed upregulation of BIM and downregulation of XIAP as seen in vitro. These results support the combination of these two classes of epigenetic regulators in treatment of melanoma including those resistant to BRAF inhibitors. PMID:26087189

  12. Encapsulation-Induced Stress Helps Saccharomyces cerevisiae Resist Convertible Lignocellulose Derived Inhibitors

    PubMed Central

    Westman, Johan O.; Manikondu, Ramesh Babu; Franzn, Carl Johan; Taherzadeh, Mohammad J.

    2012-01-01

    The ability of macroencapsulated Saccharomyces cerevisiae CBS8066 to withstand readily and not readily in situ convertible lignocellulose-derived inhibitors was investigated in anaerobic batch cultivations. It was shown that encapsulation increased the tolerance against readily convertible furan aldehyde inhibitors and to dilute acid spruce hydrolysate, but not to organic acid inhibitors that cannot be metabolized anaerobically. Gene expression analysis showed that the protective effect arising from the encapsulation is evident also on the transcriptome level, as the expression of the stress-related genes YAP1, ATR1 and FLR1 was induced upon encapsulation. The transcript levels were increased due to encapsulation already in the medium without added inhibitors, indicating that the cells sensed low stress level arising from the encapsulation itself. We present a model, where the stress response is induced by nutrient limitation, that this helps the cells to cope with the increased stress added by a toxic medium, and that superficial cells in the capsules degrade convertible inhibitors, alleviating the inhibition for the cells deeper in the capsule. PMID:23109889

  13. HDAC inhibitor-induced drug resistance involving ATP-binding cassette transporters (Review)

    PubMed Central

    NI, XUAN; LI, LI; PAN, GUOYU

    2015-01-01

    Histone deacetylase (HDAC) inhibitors are becoming a novel and promising class of antineoplastic agents that have been used for cancer therapy in the clinic. Two HDAC inhibitors, vorinostat and romidepsin, have been approved by the Food and Drug Administration to treat T-cell lymphoma. Nevertheless, similar to common anticancer drugs, HDAC inhibitors have been found to induce multidrug resistance (MDR), which is an obstacle for the success of chemotherapy. The most common cause of MDR is considered to be the increased expression of adenosine triphosphate binding cassette (ABC) transporters. Numerous studies have identified that the upregulation of ABC transporters is often observed following treatment with HDAC inhibitors, particularly the increased expression of P-glycoprotein, which leads to drug efflux, reduces intracellular drug concentration and induces MDR. The present review summarizes the key ABC transporters involved in MDR following various HDAC inhibitor treatments in a range of cancer cell lines and also explored the potential mechanisms that result in MDR, including the effect of nuclear receptors, which are the upstream regulatory factors of ABC transporters. PMID:25624882

  14. The EMT-activator ZEB1 induces bone metastasis associated genes including BMP-inhibitors

    PubMed Central

    Mock, Kerstin; Preca, Bogdan-Tiberius; Brummer, Tilman; Brabletz, Simone; Stemmler, Marc P.; Brabletz, Thomas

    2015-01-01

    Tumor cell invasion, dissemination and metastasis is triggered by an aberrant activation of epithelial-to-mesenchymal transition (EMT), often mediated by the transcription factor ZEB1. Disseminating tumor cells must acquire specific features that allow them to colonize at different organ sites. Here we identify a set of genes that is highly expressed in breast cancer bone metastasis and activated by ZEB1. This gene set includes various secreted factors, e.g. the BMP-inhibitor FST, that are described to reorganize the bone microenvironment. By inactivating BMP-signaling, BMP-inhibitors are well-known to induce osteolysis in development and disease. We here demonstrate that the expression of ZEB1 and BMP-inhibitors is correlated with bone metastasis, but not with brain or lung metastasis of breast cancer patients. In addition, we show that this correlated expression pattern is causally linked, as ZEB1 induces the expression of the BMP-inhibitors NOG, FST and CHRDL1 both by directly increasing their gene transcription, as well as by indirectly suppressing their reduction via miR-200 family members. Consequently, ZEB1 stimulates BMP-inhibitor mediated osteoclast differentiation. These findings suggest that ZEB1 is not only driving EMT, but also contributes to the formation of osteolytic bone metastases in breast cancer. PMID:25973542

  15. Peroxisome induction potential and lipid-regulating activity in rats. Quantitative microscopy and chemical structure-activity relationships.

    PubMed Central

    McGuire, E. J.; Lucas, J. A.; Gray, R. H.; de la Iglesia, F. A.

    1991-01-01

    Structurally diverse lipid-regulating agents induce hepatomegaly, hepatic peroxisome proliferation, and hepatocarcinoma in rats by mechanisms not fully understood. Nevertheless the initial hepatic response is a prompt, florid proliferation of peroxisomes. In investigations reported here, changes in the rat hepatic peroxisome compartment were measured by quantitative microscopy to determine chemical structure requirements that relate to peroxisome proliferation and lipid regulation. Aryloxyalkanoic acids plus amide analogs, and thio, benzimidazole, phenylpiperazine, and oxazole derivatives induced peroxisome proliferation and generally decreased plasma triglyceride and total cholesterol levels. These compounds contain an acidic function or are readily metabolized to a chemical with an acidic function. Substitution of the acidic function with an adamantyloxy eliminated peroxisome proliferation and induced contrasting effects on lipid profile, increasing triglycerides and decreasing total cholesterol. A previously unreported, direct correlation emerged between peroxisome proliferation and plasma high-density lipoprotein-cholesterol levels. These effects could not be elicited separately, negating identification of functional groups that could be associated with either activity. Chemical structure and resulting peroxisome proliferation with changes in plasma lipoproteins are therefore closely interrelated in rats. Images Figure 1 PMID:1853935

  16. Pseudoceramide stimulates peroxisome proliferator-activated receptor-α expression in a murine model of atopic dermatitis: molecular basis underlying the anti-inflammatory effect and the preventive effect against steroid-induced barrier impairment.

    PubMed

    Lee, Sang Eun; Jung, Min Kyung; Oh, Seung Joon; Jeong, Se Kyoo; Lee, Seung Hun

    2015-11-01

    Topical pseudoceramides are successfully used in skin barrier repair therapy for atopic dermatitis (AD) and demonstrated to reduce the adverse effects of topical glucocorticoids (GC). However, the molecular mechanisms involved are not fully understood. We investigated whether PC-9S (myristoyl/palmitoyloxostearamide/arachamide MEA, Neopharm, Daejeon, Korea), one of the synthetic pseudoceramides, could stimulate peroxisome proliferator-activated receptor (PPAR)α expression in a hapten [oxazolone (oxa)]-induced AD murine model (oxa-AD mice) and subsequently improved permeability barrier, reduced inflammation, and increased antimicrobial peptides (AMPs) expression. Normal hairless mice and oxa-AD mice were topically treated twice daily with either PC-9S-containing physiologic lipid mixture (PLM), vehicle (PLM), or PPARα agonist for 4 days. Topical PC-9S significantly increased PPARα expression in mouse epidermis in vivo and in oxa-AD mice skin comparable with PPARα agonist. Topical PC-9S-containing PLM significantly reduced basal trans-epidermal water loss (TEWL), surface pH, and mast cell infiltrates and prevented the decline of AMPs expression in oxa-AD mice, which were abrogated by PPARα antagonist. Then, oxa-AD mice were treated with super-potent topical GC twice daily for 4 days with or without PC-9S co-applications. Co-treatment with PC-9S-containing PLM suppressed GC-induced increase in basal TEWL, epidermal thinning, reduced loricrin expression, and impaired barrier recovery and these effects were attenuated by PPARα antagonist. Collectively, our findings suggest that pseudoceramide PC-9S-induced stimulation of PPARα expression provides a new mechanism by which pseudoceramides show anti-inflammatory property, improve the permeability and antimicrobial barrier function, and prevent the negative effects of topical GC. PMID:26121942

  17. Peroxisome deficient invertebrate and vertebrate animal models

    PubMed Central

    Van Veldhoven, Paul P.; Baes, Myriam

    2013-01-01

    Although peroxisomes are ubiquitous organelles in all animal species, their importance for the functioning of tissues and organs remains largely unresolved. Because peroxins are essential for the biogenesis of peroxisomes, an obvious approach to investigate their physiological role is to inactivate a Pex gene or to suppress its translation. This has been performed in mice but also in more primitive organisms including D. melanogaster, C. elegans, and D. rerio, and the major findings and abnormalities in these models will be highlighted. Although peroxisomes are generally not essential for embryonic development and organogenesis, a generalized inactivity of peroxisomes affects lifespan and posthatching/postnatal growth, proving that peroxisomal metabolism is necessary for the normal maturation of these organisms. Strikingly, despite the wide variety of model organisms, corresponding tissues are affected including the central nervous system and the testis. By inactivating peroxisomes in a cell type selective way in the brain of mice, it was also demonstrated that peroxisomes are necessary to prevent neurodegeneration. As these peroxisome deficient model organisms recapitulate pathologies of patients affected with peroxisomal diseases, their further analysis will contribute to the elucidation of still elusive pathogenic mechanisms. PMID:24319432

  18. Pex3-anchored Atg36 tags peroxisomes for degradation in Saccharomyces cerevisiae.

    PubMed

    Motley, Alison M; Nuttall, James M; Hettema, Ewald H

    2012-06-29

    Peroxisomes undergo rapid, selective autophagic degradation (pexophagy) when the metabolic pathways they contain are no longer required for cellular metabolism. Pex3 is central to the formation of peroxisomes and their segregation because it recruits factors specific for these functions. Here, we describe a novel Saccharomyces cerevisiae protein that interacts with Pex3 at the peroxisomal membrane. We name this protein Atg36 as its absence blocks pexophagy, and its overexpression induces pexophagy. We have isolated pex3 alleles blocked specifically in pexophagy that cannot recruit Atg36 to peroxisomes. Atg36 is recruited to mitochondria if Pex3 is redirected there, where it restores mitophagy in cells lacking the mitophagy receptor Atg32. Furthermore, Atg36 binds Atg8 and the adaptor Atg11 that links receptors for selective types of autophagy to the core autophagy machinery. Atg36 delivers peroxisomes to the preautophagosomal structure before being internalised into the vacuole with peroxisomes. We conclude that Pex3 recruits the pexophagy receptor Atg36. This reinforces the pivotal role played by Pex3 in coordinating the size of the peroxisome pool, and establishes its role in pexophagy in S. cerevisiae. PMID:22643220

  19. Proteasome inhibitors induce FLT3-ITD degradation through autophagy in AML cells.

    PubMed

    Larrue, Clment; Saland, Estelle; Boutzen, Hlna; Vergez, Franois; David, Marion; Joffre, Carine; Hospital, Marie-Anne; Tamburini, Jrme; Delabesse, Eric; Manenti, Stphane; Sarry, Jean Emmanuel; Rcher, Christian

    2016-02-18

    Internal tandem duplication of the Fms-like tyrosine kinase-3 receptor (FLT3) internal tandem duplication (ITD) is found in 30% of acute myeloid leukemia (AML) and is associated with a poor outcome. In addition to tyrosine kinase inhibitors, therapeutic strategies that modulate the expression of FLT3-ITD are also promising. We show that AML samples bearing FLT3-ITD mutations are more sensitive to proteasome inhibitors than wild-type samples and this sensitivity is strongly correlated with a higher FLT3-ITD allelic burden. Using pharmacologic inhibitors of autophagy, specific downregulation of key autophagy proteins including Vps34, autophagy gene (Atg)5, Atg12, Atg13, biochemical, and microscopy studies, we demonstrated that proteasome inhibitors induced cytotoxic autophagy in AML cells. FLT3-ITD molecules were detectable within autophagosomes after bortezomib treatment indicating that autophagy induction was responsible for the early degradation of FLT3-ITD, which preceded the inhibition of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK), PI3K/AKT, and STAT5 pathways, and subsequent activation of cell death. Moreover, proteasome inhibitors overcome resistance to quizartinib induced by mutations in the kinase domain of FLT3, suggesting that these compounds may prevent the emergence of mutant clones arising from tyrosine kinase inhibitor treatments. In xenograft mice models, bortezomib stimulated the conversion of LC3-I to LC3-II, indicating induction of autophagy in vivo, downregulated FLT3-ITD protein expression and improved overall survival. Therefore, selecting patients according to FLT3-ITD mutations could be a new way to detect a significant clinical activity of proteasome inhibitors in AML patients. PMID:26286850

  20. The interaction between Helminthosporium carbonum and maize: Induced resistance and the role of an inhibitor

    SciTech Connect

    Cantone, F.A.

    1989-01-01

    Helminthosporium carbonum race 1 produces large, necrotic lesions on susceptible leaves of maize, whereas race 2 causes small, chlorotic flecks. Resistance to race 1 on susceptible leaves was induced when race 2 was inoculated for at least 10 h prior to a challenge inoculation with the pathogen and was manifest as a decrease in the number of appressoria and reduced penetration by race 1 conidia. Induced resistance was prevented or reversed when HC-toxin was added to challenge race 1 inoculum. The basis for protection appears to be a volatile, inhibitory compound produced by the host. This inhibitor was always associated with treatments that resulted in resistance, whereas no inhibitory activity was detected in diffusates from susceptible reactions. The appearance of inhibitor in diffusates coincided with the appearance of protection on the leaf. In addition to race 2 of H. carbonum, other fungi (H. victoriae, H. turcicum, and Alternaria) also induced production of the inhibitor as well as resistance to race 1. The inhibitor prevented the germination of conidia of all fungi tested. The growth of two phytopathogenic bacteria was also completely inhibited. Incorporation of {sup 3}H-leucine and {sup 14}C-uridine into protein and RNA, respectively, by conidia of H. carbonum was prevented within 15 min of exposure to inhibitor. In addition, respiration of conidia in inhibitor was reduced within 90 min to just 25% of the rate of conidia germinated in water. However, inhibitory activity of the diffusates was readily reversed when conidia were rinsed with water or when organic or amino acids were added to inhibited conidia. The addition of sodium acetate to race 2 and race 1 inocula resulted in lesion enlargement and also nullified inhibitory activity in vitro.

  1. Paradoxical Reaction to Golimumab: Tumor Necrosis Factor ? Inhibitor Inducing Psoriasis Pustulosa

    PubMed Central

    Soto Lopes, Marien Siqueira; Trope, Beatriz Moritz; Rochedo Rodriguez, Maria Paula Rua; Grynszpan, Rachel Lima; Cuzzi, Tullia; Ramos-e-Silva, Marcia

    2013-01-01

    Importance Golimumab is a human monoclonal antibody, used for rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis. Adverse reactions are increasing with this class of medication (tumor necrosis factor ? inhibitors). Observations The authors present a case of a female patient who presented with psoriasis pustulosa after the use of golimumab for rheumatoid arthritis. Conclusions and Relevance Paradoxically, in this case, golimumab, which is used for psoriasis, induced the pustular form of this disease. We are observing an increasing number of patients who develop collateral effects with tumor necrosis factor ? inhibitors, and the understanding of the mechanism of action and how these adverse reactions occur may contribute to avoid these sometimes severe situations. PMID:24348382

  2. BRAF Inhibitor-Induced Panniculitis: Appearance on 18F-FDG PET/CT.

    PubMed

    Broski, Stephen M; Moran, Erin K; Glazebrook, Katrina N; Nathan, Mark A

    2016-03-01

    BRAF inhibitors vemurafenib and dabrafenib have become the standard of care for treatment of stage IV metastatic melanoma harboring a BRAF mutation. Panniculitis is a rare but known adverse side effect of these agents and presents with tender erythematous nodules. These nodules may demonstrate uptake on F-FDG PET/CT, which may mimic metastatic disease in patients undergoing treatment. We present a case of BRAF inhibitor-induced panniculitis in a patient with stage IV metastatic melanoma and discuss the imaging findings on F-FDG PET/CT. PMID:26447389

  3. NOVEL ATYPICAL PKC INHIBITORS PREVENT VASCULAR ENDOTHELIAL GROWTH FACTOR-INDUCED BLOOD-RETINAL BARRIER DYSFUNCTION

    PubMed Central

    Titchenell, Paul M.; Lin, Cheng-Mao; Keil, Jason M.; Sundstrom, Jeffrey M.; Smith, Charles D.; Antonetti, David A.

    2013-01-01

    SYNOPSIS Pro-inflammatory cytokines and growth factors such as vascular endothelial growth factor (VEGF) contribute to the loss of the blood-retinal barrier (BRB) and subsequent macular edema in various retinal pathologies. VEGF signaling requires conventional PKC (PKC?) activity; however, PKC? inhibition only partially prevents VEGF-induced endothelial permeability and does not affect pro-inflammatory cytokine-induced permeability suggesting the involvement of alternative signaling pathways. Here, we provide evidence for the involvement of atypical protein kinase C (aPKC) signaling in VEGF-induced endothelial permeability and identify a novel class of inhibitors of aPKC that prevent BRB breakdown in vivo. Genetic and pharmacological manipulations of aPKC isoforms were used to assess their contribution to endothelial permeability in culture. A chemical library was screened using an in vitro kinase assay to identify novel small molecule inhibitors and further medicinal chemistry was performed to delineate a novel pharmacophore. We demonstrate that aPKC isoforms are both sufficient and required for VEGF-induced endothelial permeability. Furthermore, these specific, potent, non-competitive, small molecule inhibitors prevented VEGF-induced tight junction internalization and retinal endothelial permeability in response to VEGF in both primary culture and in rodent retina. These data suggest that aPKC inhibition with 2-amino-4-phenyl-thiophene derivatives may be developed to preserve the BRB in retinal diseases such as diabetic retinopathy or uveitis and the blood-brain barrier (BBB) in the presence of brain tumors. PMID:22721706

  4. Wound-Inducible Proteinase Inhibitors in Pepper. Differential Regulation upon Wounding, Systemin, and Methyl Jasmonate1

    PubMed Central

    Moura, Daniel S.; Ryan, Clarence A.

    2001-01-01

    Seven small (approximately 6,000 D) wound-inducible proteinase inhibitor proteins were isolated from leaves of pepper (Capsicum annuum) plants that are members of the potato inhibitor II family. N-terminal sequences obtained indicated that the pepper leaf proteinase inhibitors (PLPIs) exhibit homology to two GenBank accessions that code for preproteins containing three isoinhibitors domains each that, when post-translationally processed, can account for the mixture of isoinhibitors that are reported herein from pepper leaves. A constitutive level of PLPI proteins was found in pepper leaves, and these levels increased up to 2.6-fold upon wounding of the lower leaves. Exposing intact plants to methyl jasmonate vapors induced the accumulation of PLPIs. Supplying excised young pepper plants with water through the cut stems induced PLPI proteins to levels higher than those found in intact plants, but with high variability. Supplying the excised plants with systemin did not result in an increase of PLPI levels that were statistically higher than levels found in excised plants. Gel-blot analyses of PLPI induction revealed the presence of two mRNA bands, having slightly different mobilities in agarose gels. Only the low Mr mRNA is present in untreated control plants, and it appears to be responsible for the constitutive levels of PLPI found in leaves. Both mRNA species are wound- and methyl jasmonate-inducible. Only the low- Mr species is weakly induced by systemin, indicating a differential expression of the two PLPI species. PMID:11351092

  5. Neutral endopeptidase inhibitors potentiate substance P- and capsaicin-induced cough in awake guinea pigs.

    PubMed Central

    Kohrogi, H; Graf, P D; Sekizawa, K; Borson, D B; Nadel, J A

    1988-01-01

    To study the roles of substance P and endogenous neutral endopeptidase in mediating cough, we measured cough responses in awake guinea pigs in response to exogenous substance P and capsaicin aerosols in the presence and absence of the neutral endopeptidase inhibitors leucine-thiorphan and phosphoramidon. Substance P stimulated cough in very low concentrations (10(-17)-10(-16) M). In a second study where the investigator did not know whether substance P or diluent alone was aerosolized, substance P (10(-16) M) caused cough. Leucine-thiorphan (10(-5) M) and phosphoramidon (10(-5) M) potentiated substance P-induced cough; NEP inhibitors also potentiated capsaicin-induced cough significantly. These findings suggest that substance P is a potent stimulator of cough responses, that capsaicin-induced cough is mediated by substance P or another similar neuropeptide, and that cough responses are modulated by endogenous neutral endopeptidase. PMID:2461967

  6. Proteins and enzymes of the peroxisomal membrane in mammals.

    PubMed

    Causeret, C; Bentejac, M; Bugaut, M

    1993-01-01

    Proteins of the peroxisomal membrane can be schematically divided into two groups, one being made up of more or less characterized proteins with generally unknown functions and the other consisting of enzyme activities of which the corresponding proteins have not been characterized. In the present report, these proteins and enzymes are described with the addition of unpublished results regarding their induction by peroxisome proliferators at the post-transcriptional level. Integral membrane proteins (IMPs) can be isolated using an alkaline solution of sodium carbonate. A dozen of preponderant IMPs can be seen on sodium dodecyl sulfate polyacrylamide gel electrophoresis, and the major band corresponds to a 70 kDa IMP, of which the corresponding rat cDNA is known. Some IMPs have been characterized by immunoblot analysis. Recently, a cDNA has been cloned for a peroxisome assembly factor (35 kDa IMP). Functions have also been proposed for some IMPs but are not yet firmly settled. Some IMPs (450/520, 70 and 26 kDa) are strongly induced by peroxisome proliferators. Our results extend to cipro- and fenofibrate the observation that the 70 kDa IMP mRNA level is strongly increased in di(2-ethylhexyl)phtalate-treated rats. All the enzyme activities associated with the peroxisomal membrane are involved in lipid metabolism: activation of substrates (fatty acids), ether lipid biosynthesis, and formation of precursors (fatty alcohols). It is believed that the same long-chain acyl-CoA synthetase occurs in the peroxisome as well as in the outer mitochondrial membrane and the endoplasmic reticulum. However, two highly homologous but different cDNAs encoding rat liver and brain long-chain acyl-CoA synthetases have been isolated recently. Evidence has been accumulated for a distinct synthetase that specifically activates very-long chain fatty acids. The first two steps of ether lipid biosynthesis require dihydroxyacetone-phosphate (DHAP) acyltransferase and alkyl-DHAP synthetase, the active sites of which are located on the inner surface of the membrane. In contrast, the catalytic site of the acyl/alkyl-DHAP reductase, which generates sn-1-alkyl-glycerol-3-phosphate, is located on the outer surface. Long-chain fatty alcohols, which are obligate precursors of ether lipids and wax esters, are biosynthetized by the reduction of the corresponding acyl-CoAs via the action of an acyl-CoA reductase. Peroxisome proliferators do not appear to stimulate these enzyme activities specifically. However, we report that feno- and ciprofibrate treatments increase six-fold the palmitoyl-CoA synthetase mRNA level in the rat liver. PMID:8518748

  7. Inhibition of Interleukin-1?-Induced Group IIA Secretory Phospholipase A2 Expression by Peroxisome Proliferator-Activated Receptors (PPARs) in Rat Vascular Smooth Muscle Cells: Cooperation between PPAR? and the Proto-Oncogene BCL-6?

    PubMed Central

    Ravaux, Lucas; Denoyelle, Chantal; Monne, Claire; Limon, Isabelle; Raymondjean, Michel; El Hadri, Khadija

    2007-01-01

    The inflammation that occurs during atherosclerosis is characterized by the release of large amounts of group IIA secretory phospholipase A2 (sPLA2-IIA). This study was designed to define the function of the three peroxisome proliferator-activated receptors (PPARs) on sPLA2 expression in vascular smooth muscle cells (VSMCs). We found that PPAR ligands decreased sPLA2-IIA activity and inhibited mRNA accumulation under inflammatory conditions. Furthermore, interleukin-1?-induced sPLA2-IIA promoter activity was inhibited by the three PPAR ligands and in a similar way when cells were cotransfected with PPAR?, PPAR?, or PPAR?, plus retinoid X receptor ? (RXR?). Our study revealed that the regulation of sPLA2-IIA gene transcription by PPAR?/RXR and PPAR?/RXR heterodimers requires an interaction with a PPAR response element (PPRE) of the sPLA2-IIA promoter. In contrast, PPAR? operates through a PPRE-independent mechanism. In addition, we demonstrated that VSMCs expressed the transcriptional repressor BCL-6. Overexpression of BCL-6 markedly reduced sPLA2-IIA promoter activity in VSMCs, while a dominant negative form of BCL-6 abrogated sPLA2 repression by PPAR?. The PPAR? agonist induced a BCL-6 binding to the sPLA2 promoter in VSMCs under inflammatory conditions. The knockdown of BCL-6 by short interfering RNA abolished the inhibitory effect of the PPAR? ligand on sPLA2 activity and prostaglandin E2 release. Thus, the inhibition of sPLA2-IIA activity by PPAR? agonists may provide a promising approach to impacting the initiation and progression of atherosclerosis. PMID:17908795

  8. A novel histone deacetylase inhibitor Chidamide induces apoptosis of human colon cancer cells

    SciTech Connect

    Liu, Lin; Chen, Baoan; Qin, Shukui; Li, Suyi; He, Xiangming; Qiu, Shaomin; Zhao, Wei; Zhao, Hong

    2010-02-05

    Many studies have demonstrated that histone deacetylase (HDAC) inhibitors induce various tumor cells to undergo apoptosis, and such inhibitors have been used in different clinical trials against different human cancers. In this study, we designed and synthesized a novel HDAC inhibitor, Chidamide. We showed that Chidamide was able to increase the acetylation levels of histone H3 and to inhibit the PI3K/Akt and MAPK/Ras signaling pathways, which resulted in arresting colon cancer cells at the G1 phase of the cell cycle and promoting apoptosis. As a result, the proliferation of colon cancer cells was suppressed in vitro. Our data support the potential application of Chidamide as an anticancer agent in treating colon cancer. Future studies are needed to demonstrate its in vivo efficacy.

  9. Aromatase Inhibitor-Induced Erythrocytosis in a Patient Undergoing Hormonal Treatment for Breast Cancer

    PubMed Central

    Yeruva, Sri Lakshmi Hyndavi; Ogbonna, Onyekachi Henry; Oneal, Patricia

    2015-01-01

    Aromatase inhibitors (AIs) are most commonly used for breast cancer patients with hormone receptor positive disease. Although the side effect profile of aromatase inhibitors is well known, including common side effects like arthralgia, bone pain, arthritis, hot flashes, and more serious problems like osteoporosis, we present a case of an uncommon side effect of these medications. We report the case of a postmenopausal woman on adjuvant hormonal therapy with anastrozole after completing definitive therapy for stage IIIB estrogen receptor-positive breast cancer, who was referred to hematology service for evaluation of persistent erythrocytosis. Primary and known secondary causes of polycythemia were ruled out. On further evaluation, we found that her erythrocytosis began after initiation of anastrozole and resolved after it was discontinued. We discuss the pathophysiology of aromatase inhibitor-induced erythrocytosis and reference of similar cases reported in the literature. PMID:26137331

  10. Characterization of a novel component of the peroxisomal protein import apparatus using fluorescent peroxisomal proteins.

    PubMed Central

    Kalish, J E; Keller, G A; Morrell, J C; Mihalik, S J; Smith, B; Cregg, J M; Gould, S J

    1996-01-01

    Fluorescent peroxisomal probes were developed by fusing green fluorescent protein (GFP) to the matrix peroxisomal targeting signals PTS1 and PTS2, as well as to an integral peroxisomal membrane protein (IPMP). These proteins were used to identify and characterize novel peroxisome assembly (pas) mutants in the yeast Pichia pastoris. Mutant cells lacking the PAS10 gene mislocalized both PTS1-GFP and PTS2-GFP to the cytoplasm but did incorporate IPMP-GFP into peroxisome membranes. Similar distributions were observed for endogenous peroxisomal matrix and membrane proteins. While peroxisomes from translocation-competent pas mutants sediment in sucrose gradients at the density of normal peroxisomes, >98% of peroxisomes from pas10 cells migrated to a much lower density and had an extremely low ratio of matrix:membrane protein. These data indicate that Pas10p plays an important role in protein translocation across the peroxisome membrane. Consistent with this hypothesis, we find that Pas10p is an integral protein of the peroxisome membrane. In addition, Pas10p contains a cytoplasmically-oriented C3HC4 zinc binding domain that is essential for its biological activity. Images PMID:8670828

  11. Arginine improves peroxisome functioning in cells from patients with a mild peroxisome biogenesis disorder

    PubMed Central

    2013-01-01

    Background Zellweger spectrum disorders (ZSDs) are multisystem genetic disorders caused by a lack of functional peroxisomes, due to mutations in one of the PEX genes, encoding proteins involved in peroxisome biogenesis. The phenotypic spectrum of ZSDs ranges from an early lethal form to much milder presentations. In cultured skin fibroblasts from mildly affected patients, peroxisome biogenesis can be partially impaired which results in a mosaic catalase immunofluorescence pattern. This peroxisomal mosaicism has been described for specific missense mutations in various PEX genes. In cell lines displaying peroxisomal mosaicism, peroxisome biogenesis can be improved when these are cultured at 30C. This suggests that these missense mutations affect the folding and/or stability of the encoded protein. We have studied if the function of mutant PEX1, PEX6 and PEX12 can be improved by promoting protein folding using the chemical chaperone arginine. Methods Fibroblasts from three PEX1 patients, one PEX6 and one PEX12 patient were cultured in the presence of different concentrations of arginine. To determine the effect on peroxisome biogenesis we studied the following parameters: number of peroxisome-positive cells, levels of PEX1 protein and processed thiolase, and the capacity to ?-oxidize very long chain fatty acids and pristanic acid. Results Peroxisome biogenesis and function in fibroblasts with mild missense mutations in PEX1, 6 and 12 can be improved by arginine. Conclusion Arginine may be an interesting compound to promote peroxisome function in patients with a mild peroxisome biogenesis disorder. PMID:24016303

  12. Synergistic effect of apoptosis and necroptosis inhibitors in cisplatin-induced nephrotoxicity.

    PubMed

    Tristo, Vivian Regina; Pessoa, Edson A; Nakamichi, Renata; Reis, Luciana A; Batista, Marcelo Costa; de Souza Duro Junior, Marcelino; Monte, Jlio Cesar Martins

    2016-01-01

    Necroptosis is a nonapoptotic cell death pathway. We aim to study the effect of necrostatin-1 (a specific necroptosis inhibitor) in cisplatin-induced injury. We analyzed the effect of the combined use of inhibitors of apoptosis (z-vad) and necroptosis (necrostatin-1) in acute kidney injury by cisplatin in human proximal tubule cells. Our results showed moderate effectiveness in cytoprotection after treatment with z-vad. But the concomitant use of inhibitors (z-vad and necrostatin-1) presented synergistic and additive protection. The present study analyzed the caspase-3 activity and we observed a significant decrease in the group treated with z-vad and cisplatin. However we did not observe changes in the group treated with both inhibitors (z-vad and necrostatin-1) and cisplatin. Thus, demonstrating that necroptosis is a caspase-independent mechanism. We also analyzed the effect of necrostatin-1 in vivo model. C57BL/6 mice were treated with cisplatin and/or inhibitors. The concomitant use of inhibitors (z-vad and necrostatin-1) recovered renal function and decreased levels of urinary Ngal. Additionally, we analyzed the expression of RIP-1, a specific marker for necroptosis. In animals treated with cisplatin and z-VAD levels of RIP-1 were higher. This result reinforces that necroptosis occurs only in conditions where apoptosis was blocked. However, the use of both inhibitors (z-vad and necrostatin-1) provided additional protection. In conclusion, our study has a significant potential to show in vitro and in vivo protection obtained by necrostatin-1. Therefore, our results suggest that necroptosis may be an important mechanism of cell death after kidney injury. PMID:26519037

  13. Metabolite transport across the peroxisomal membrane.

    PubMed

    Visser, Wouter F; van Roermund, Carlo W T; Ijlst, Lodewijk; Waterham, Hans R; Wanders, Ronald J A

    2007-01-15

    In recent years, much progress has been made with respect to the unravelling of the functions of peroxisomes in metabolism, and it is now well established that peroxisomes are indispensable organelles, especially in higher eukaryotes. Peroxisomes catalyse a number of essential metabolic functions including fatty acid beta-oxidation, ether phospholipid biosynthesis, fatty acid alpha-oxidation and glyoxylate detoxification. The involvement of peroxisomes in these metabolic pathways necessitates the transport of metabolites in and out of peroxisomes. Recently, considerable progress has been made in the characterization of metabolite transport across the peroxisomal membrane. Peroxisomes posses several specialized transport systems to transport metabolites. This is exemplified by the identification of a specific transporter for adenine nucleotides and several half-ABC (ATP-binding cassette) transporters which may be present as hetero- and homo-dimers. The nature of the substrates handled by the different ABC transporters is less clear. In this review we will describe the current state of knowledge of the permeability properties of the peroxisomal membrane. PMID:17173541

  14. Peroxisomes in brain development and function.

    PubMed

    Berger, Johannes; Dorninger, Fabian; Forss-Petter, Sonja; Kunze, Markus

    2016-05-01

    Peroxisomes contain numerous enzymatic activities that are important for mammalian physiology. Patients lacking either all peroxisomal functions or a single enzyme or transporter function typically develop severe neurological deficits, which originate from aberrant development of the brain, demyelination and loss of axonal integrity, neuroinflammation or other neurodegenerative processes. Whilst correlating peroxisomal properties with a compilation of pathologies observed in human patients and mouse models lacking all or individual peroxisomal functions, we discuss the importance of peroxisomal metabolites and tissue- and cell type-specific contributions to the observed brain pathologies. This enables us to deconstruct the local and systemic contribution of individual metabolic pathways to specific brain functions. We also review the recently discovered variability of pathological symptoms in cases with unexpectedly mild presentation of peroxisome biogenesis disorders. Finally, we explore the emerging evidence linking peroxisomes to more common neurological disorders such as Alzheimer's disease, autism and amyotrophic lateral sclerosis. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26686055

  15. Histone deacetylase inhibitors induce apoptosis in both Type I and Type II endometrial cancer cells

    PubMed Central

    Jiang, Shujuan; Dowdy, Sean C.; Meng, Xue W.; Wang, Zhaoyu; Jones, Monica B.; Podratz, Karl C.; Jiang, Shi-Wen

    2012-01-01

    Objective To characterize the molecular pathways involved in apoptosis following administration of histone deacetylase inhibitors to Type I and II endometrial cancer cells. Methods Ark2, Ishikawa, and AN3 cell lines representing both Type I and II endometrial cancers were treated with various concentrations of oxamflatin and HDAC inhibitor-1. Cell apoptosis was determined by flow cytometry, nuclear staining, Western blotting, and mitochondrial membrane potential assays. Results Compared to controls, there was a 95% reduction in the growth of Ark2 cells following administration of histone deacetylase inhibitors and this response was dose-dependent. These agents also caused profound morphologic changes and loss of mitochondrial membrane potentials consistent with the induction of apoptosis. Cleavage of PARP, caspase-9, and caspase-8 was detected, confirming the activation of apoptotic cascades in endometrial carcinoma cells. This effect was present in both serous and endometrioid cell types. Conclusion Our results suggest that oxamflatin and HDAC inhibitor-1 have potent cytotoxicity in endometrial cancer cells by inducing cell apoptosis. Histone deacetylase inhibitors are promising agents for the treatment of both Type I and II endometrial carcinoma. PMID:17303224

  16. Small-Molecule XIAP Inhibitors Enhance ?-Irradiation-Induced Apoptosis in Glioblastoma12

    PubMed Central

    Vellanki, Sri Hari Krishna; Grabrucker, Andreas; Liebau, Stefan; Proepper, Christian; Eramo, Adriana; Braun, Veit; Boeckers, Tobias; Debatin, Klaus-Michael; Fulda, Simone

    2009-01-01

    Because evasion of apoptosis can cause radioresistance of glioblastoma, there is a need to design rational strategies that counter apoptosis resistance. In the present study, we investigated the potential of targeting the antiapoptotic protein XIAP for the radiosensitization of glioblastoma. Here, we report that small-molecule XIAP inhibitors significantly enhance ?-irradiation-induced loss of viability and apoptosis and cooperate with ?-irradiation to suppress clonogenic survival of glioblastoma cells. Analysis of molecular mechanisms reveals that XIAP inhibitors act in concert with ?-irradiation to cause mitochondrial outer membrane permeabilization, caspase activation, and caspase-dependent apoptosis. Importantly, XIAP inhibitors also sensitize primary cultured glioblastoma cells derived from surgical specimens as well as glioblastoma-initiating stemlike cancer stem cells for ?-irradiation. In contrast, they do not increase the toxicity of ?-irradiation on some nonmalignant cells of the central nervous system, including rat neurons or glial cells, pointing to some tumor selectivity. In conclusion, by demonstrating for the first time that small-molecule XIAP inhibitors increase the radiosensitivity of glioblastoma cells while sparing normal cells of the central nervous system, our findings build the rationale for further (pre)clinical development of XIAP inhibitors in combination with ?-irradiation in glioblastoma. PMID:19649204

  17. Inhibition of peroxisome fission, but not mitochondrial fission, increases yeast chronological lifespan

    PubMed Central

    Lefevre, Sophie D; Kumar, Sanjeev; van der Klei, Ida J

    2015-01-01

    Mitochondria are key players in aging and cell death. It has been suggested that mitochondrial fragmentation, mediated by the Dnm1/Fis1 organelle fission machinery, stimulates aging and cell death. This was based on the observation that Saccharomyces cerevisiae ?dnm1 and ?fis1 mutants show an enhanced lifespan and increased resistance to cell death inducers. However, the Dnm1/Fis1 fission machinery is also required for peroxisome division. Here we analyzed the significance of peroxisome fission in yeast chronological lifespan, using yeast strains in which fission of mitochondria was selectively blocked. Our data indicate that the lifespan extension caused by deletion of FIS1 is mainly due to a defect in peroxisome fission and not caused by a block in mitochondrial fragmentation. These observations are underlined by our observation that deletion of FIS1 does not lead to lifespan extension in yeast peroxisome deficient mutant cells. PMID:25840089

  18. Activation of peroxisome proliferator-activated receptors by chlorinated hydrocarbons and endogenous steroids.

    PubMed Central

    Zhou, Y C; Waxman, D J

    1998-01-01

    Trichloroethylene (TCE) and related hydrocarbons constitute an important class of environmental pollutants whose adverse effects on liver, kidney, and other tissues may, in part, be mediated by peroxisome proliferator-activated receptors (PPARs), ligand-activated transcription factors belonging to the steroid receptor superfamily. Activation of PPAR induces a dramatic proliferation of peroxisomes in rodent hepatocytes and ultimately leads to hepatocellular carcinoma. To elucidate the role of PPAR in the pathophysiologic effects of TCE and its metabolites, it is important to understand the mechanisms whereby PPAR is activated both by TCE and endogenous peroxisome proliferators. The investigations summarized in this article a) help clarify the mechanism by which TCE and its metabolites induce peroxisome proliferation and b) explore the potential role of the adrenal steroid and anticarcinogen dehydroepiandrosterone 3beta-sulfate (DHEA-S) as an endogenous PPAR activator. Transient transfection studies have demonstrated that the TCE metabolites trichloroacetate and dichloroacetate both activate PPAR alpha, a major liver-expressed receptor isoform. TCE itself was inactive when tested over the same concentration range, suggesting that its acidic metabolites mediate the peroxisome proliferative potential of TCE. Although DHEA-S is an active peroxisome proliferator in vivo, this steroid does not stimulate trans-activation of PPAR alpha or of two other PPAR isoforms, gamma and delta/Nuc1, when evaluated in COS-1 cell transfection studies. To test whether PPAR alpha mediates peroxisomal gene induction by DHEA-S in intact animals, DHEA-S has been administered to mice lacking a functional PPAR alpha gene. DHEA-S was thus shown to markedly increase hepatic expression of two microsomal P4504A proteins associated with the peroxisomal proliferative response in wild-type mice. In contrast, DHEA-S did not induce these hepatic proteins in PPAR alpha-deficient mice. Thus, despite its unresponsiveness to steroidal peroxisome proliferators in transfection assays, PPAR alpha is an obligatory mediator of DHEA-S-stimulated hepatic peroxisomal gene induction. DHEA-S, or one of its metabolites, may thus serve as an important endogenous regulator of liver peroxisomal enzyme expression. Images Figure 2 Figure 3 PMID:9703482

  19. Pulsed EPR Characterization of HIV-1 Protease Conformational Sampling and Inhibitor-Induced Population Shifts

    PubMed Central

    Liu, Zhanglong; Casey, Thomas M.; Blackburn, Mandy E.; Huang, Xi; Pham, Linh; de Vera, Ian Mitchelle S.; Carter, Jeffrey D.; Kear-Scott, Jamie L.; Veloro, Angelo M.; Galiano, Luis; Fanucci, Gail E.

    2015-01-01

    The conformational landscape of HIV-1 protease (PR) can be experimentally characterized by pulsed-EPR double electron-electron resonance (DEER). For this characterization, nitroxide spin labels are attached to an engineered cysteine residue in the flap region of HIV-1 PR. DEER distance measurements from spin-labels contained within each flap of the homodimer provide a detailed description of the conformational sampling of apo-enzyme as well as induced conformational shifts as a function inhibitor binding. The distance distribution profiles are further interpreted in terms of a conformational ensemble scheme that consists of four unique states termed “curled/tucked”, “closed”, “semi-open” and “wide-open” conformations. Reported here are the DEER results for a drug-resistant variant clinical isolate sequence, V6, in the presence of FDA approved protease inhibitors (PIs) as well as a non-hydrolyzable substrate mimic, CaP2. Results are interpreted in the context of the current understanding of the relationship between conformational sampling, drug resistance, and kinetic efficiency of HIV-1PR as derived from previous DEER and kinetic data for a series of HIV-1PR constructs that contain drug-pressure selected mutations or natural polymorphisms. Specifically, these collective results support the notion that inhibitor-induced closure of the flaps correlates with inhibitor efficiency and drug resistance. This body of work also suggests DEER as a tool for studying conformational sampling in flexible enzymes as it relates to function. PMID:26489725

  20. Pulsed EPR characterization of HIV-1 protease conformational sampling and inhibitor-induced population shifts.

    PubMed

    Liu, Zhanglong; Casey, Thomas M; Blackburn, Mandy E; Huang, Xi; Pham, Linh; de Vera, Ian Mitchelle S; Carter, Jeffrey D; Kear-Scott, Jamie L; Veloro, Angelo M; Galiano, Luis; Fanucci, Gail E

    2016-02-17

    The conformational landscape of HIV-1 protease (PR) can be experimentally characterized by pulsed-EPR double electron-electron resonance (DEER). For this characterization, nitroxide spin labels are attached to an engineered cysteine residue in the flap region of HIV-1 PR. DEER distance measurements from spin-labels contained within each flap of the homodimer provide a detailed description of the conformational sampling of apo-enzyme as well as induced conformational shifts as a function of inhibitor binding. The distance distribution profiles are further interpreted in terms of a conformational ensemble scheme that consists of four unique states termed "curled/tucked", "closed", "semi-open" and "wide-open" conformations. Reported here are the DEER results for a drug-resistant variant clinical isolate sequence, V6, in the presence of FDA approved protease inhibitors (PIs) as well as a non-hydrolyzable substrate mimic, CaP2. Results are interpreted in the context of the current understanding of the relationship between conformational sampling, drug resistance, and kinetic efficiency of HIV-1PR as derived from previous DEER and kinetic data for a series of HIV-1PR constructs that contain drug-pressure selected mutations or natural polymorphisms. Specifically, these collective results support the notion that inhibitor-induced closure of the flaps correlates with inhibitor efficiency and drug resistance. This body of work also suggests DEER as a tool for studying conformational sampling in flexible enzymes as it relates to function. PMID:26489725

  1. Why do peroxisomes associate with the cytoskeleton?

    PubMed

    Neuhaus, Alexander; Eggeling, Christian; Erdmann, Ralf; Schliebs, Wolfgang

    2016-05-01

    Attachment of peroxisomes to cytoskeleton and movement along microtubular filaments and actin cables are essential and highly regulated processes enabling metabolic efficiency, biogenesis, maintenance and inheritance of this dynamic cellular compartment. Several peroxisome-associated proteins have been identified, which mediate interaction with motor proteins, adaptor proteins or other constituents of the cytoskeleton. It appears that there is a species-specific complexity of protein-protein interactions required to control directional movement and arresting. An open question is why some proteins with a specific role in peroxisomal protein import have an additional function in the regulation of cytoskeleton binding and motility of peroxisomes. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26616035

  2. Dipeptidyl Peptidase IV Inhibitor MK-0626 Attenuates Pancreatic Islet Injury in Tacrolimus-Induced Diabetic Rats

    PubMed Central

    Doh, Kyoung Chan; Piao, Shang Guo; Jin, Jian; Heo, Seong Beom; Chung, Byung Ha; Yang, Chul Woo

    2014-01-01

    Background Tacrolimus (TAC)-induced pancreatic islet injury is one of the important causes of new-onset diabetes in transplant recipients. This study was performed to evaluate whether a dipeptidyl peptidase IV (DPP IV) inhibitor is effective in improving TAC-induced diabetes mellitus by reducing pancreatic islet injury. Methods Rats were treated with TAC (1.5 mg/kg, subcutaneously) and the DPP IV inhibitor MK-0626 (10 or 20 mg/kg, oral gavage) for 4 weeks. The effect of MK-0626 on TAC-induced diabetes was evaluated by assessing pancreatic islet function, histopathology. TAC-induced incretin dysfunction was also examined based on active glucagon-like peptide-1 (GLP-1) levels in the serum after glucose loading. The protective effect of MK-0626 was evaluated by measuring markers of oxidative stress, oxidative resistance, and apoptosis. To determine whether enhanced GLP-1 signaling is associated with these protective effects, we measured the expression of the GLP-1 receptor (GLP-1R) and the effect of the GLP-1 analog exendin-4 on cell viability and oxidative stress in isolated islets. Results MK-0626 treatment attenuated TAC-induced pancreatic islet dysfunction and islet morphology. TAC treatment led to a defect in active GLP-1 secretion; however, MK-0626 reversed these effects. TAC treatment increased the level of 8-hydroxy-2?-deoxyguanosine (8-OHdG), the number of apoptotic death, and the level of active caspase-3, and decreased the level of manganese superoxide dismutase and heme oxygenase-1; MK-0626 treatment reversed these changes. MK-0626 treatment restored the expression of GLP-1R, and direct administration of exendin-4 to isolated islets reduced TAC-induced cell death and 8-OHdG expression. Conclusions The DPP IV inhibitor MK-0626wasan effective antidiabetic agent that exerted antioxidative and antiapoptotic effects via enhanced GLP-1 signaling in TAC-induced diabetics. PMID:24959755

  3. Involvement of caspase family proteases in FPT inhibitor III-induced apoptosis in human ovarian cancer cells.

    PubMed

    Hung, W C; Chuang, L Y

    1998-06-01

    We have previously demonstrated that a new farnesyltransferase inhibitor, FPT inhibitor III, triggers apoptosis in human ovarian cancer cells. Here, we report that induction of apoptotic cell death in PA-1 ovarian cancer cells by FPT inhibitor III was accompanied by the activation of interleukin-1 #-converting enzyme (ICE)-like proteases, which have recently been renamed as caspases. The caspase inhibitor, ZVAD-FMK, which inhibits a number of caspase family proteases, blocked FPT inhibitor III-induced apoptotic cell death in a dose-dependent manner. Additionally, cleavage of poly(ADP-ribose) polymerase, an identified in vivo substrate for caspase family proteases, in FPT inhibitor III-treated cells was confirmed by immunoblotting. Our results suggest that the caspase family proteases are involved in the induction of apoptosis triggered by FPT inhibitor III. PMID:9592196

  4. Effect of ACE inhibitors and AT1 receptor antagonists on pentylenetetrazole-induced convulsions in mice.

    PubMed

    ?ukawski, Krzysztof; Czuczwar, Stanis?aw Jerzy

    2015-05-01

    Experimental data show that some angiotensin-converting enzyme (ACE) inhibitors and angiotensin AT(1) receptor antagonists that are normally used as antihypertensive drugs can exert anticonvulsant-like activity against audiogenic seizures. In the current study, a number of ACE inhibitors (captopril, enalapril, cilazapril, perindopril and zofenopril) and AT(1) antagonists (losartan, telmisartan and candesartan) were examined against pentylenetetrazole (PTZ)-induced seizures in mice. Captopril (50 mg/kg) administered intraperitoneally significantly raised the PTZ threshold (p < 0.05). The remaining drugs were not protective against PTZ-induced convulsions. The current study indicates that captopril decreases PTZ-evoked seizures in mice, which is an animal model of myoclonic convulsions. PMID:25573423

  5. Inhibitors of hypoxia-inducible factor 1 block breast cancer metastatic niche formation and lung metastasis.

    PubMed

    Wong, Carmen Chak-Lui; Zhang, Huafeng; Gilkes, Daniele M; Chen, Jasper; Wei, Hong; Chaturvedi, Pallavi; Hubbi, Maimon E; Semenza, Gregg L

    2012-07-01

    Intratumoral hypoxia, a frequent finding in metastatic cancer, results in the activation of hypoxia-inducible factors (HIFs). HIFs are implicated in many steps of breast cancer metastasis, including metastatic niche formation through increased expression of lysyl oxidase (LOX) and lysyl oxidase-like (LOXL) proteins, enzymes that remodel collagen at the metastatic site and recruit bone marrow-derived cells (BMDCs) to the metastatic niche. We investigated the effect of two chemically and mechanistically distinct HIF inhibitors, digoxin and acriflavine, on breast cancer metastatic niche formation. Both drugs blocked the hypoxia-induced expression of LOX and LOXL proteins, collagen cross-linking, CD11b? BMDC recruitment, and lung metastasis in an orthotopic breast cancer model. Patients with HIF-1 ?-overexpressing breast cancers are at increased risk of metastasis and mortality and our results suggest that such patients may benefit from aggressive therapy that includes a HIF inhibitor. PMID:22231744

  6. PS-341 and Histone Deacetylase Inhibitor Synergistically Induce Apoptosis in Head and Neck Squamous Cell Carcinoma Cells

    PubMed Central

    Kim, JinKoo; Guan, Jean; Chang, Insoon; Chen, Xiaohong; Han, Demin; Wang, Cun-Yu

    2010-01-01

    Proteasome inhibitor PS-341 (also known as Bortezomib) and histone deacetylase (HDAC) inhibitors have emerged as novel therapeutic agents for a variety of malignancies. In this study, we examined whether PS-341 and the HDAC inhibitor trichostatin A (TSA) induced apoptosis in head and neck squamous cell carcinoma (HNSCC), a common and lethal malignancy. We found that, while TSA treatment alone did not induce apoptosis in HNSCC cells, it significantly enhanced PS-341-induced apoptosis in HNSCC cells in vitro. Consistently, TSA significantly improved PS-341-mediated inhibition of HNSCC tumor growth in nude mice. Mechanistically, we found that TSA increased PS-341-induced Noxa expression and caspase activation in HNSCC cells. The knock-down of Noxa significantly reduced apoptosis induced by co-treatment of PS-341 and TSA. Taken together, our results provide new insight into the mechanisms of synergistic antitumor activity of PS-341 and HDAC inhibitor regimen, offering a new therapeutic strategy for HNSCC patients. PMID:20571067

  7. Network-level effects of kinase inhibitors modulate TNF-?-induced apoptosis in the intestinal epithelium.

    PubMed

    Gierut, Jessica J; Wood, Levi B; Lau, Ken S; Lin, Yi-Jang; Genetti, Casie; Samatar, Ahmed A; Lauffenburger, Douglas A; Haigis, Kevin M

    2015-01-01

    Individual signaling pathways operate in the context of the broader signaling network. Thus, the response of a cell to signals from the environment is affected by the state of the signaling network, such as the clinically relevant example of whether some components in the network are inhibited. The cytokine tumor necrosis factor-? (TNF-?) promotes opposing cellular behaviors under different conditions; the outcome is influenced by the state of the network. For example, in the mouse intestinal epithelium, inhibition of the mitogen-activated protein kinase (MAPK) kinase MEK alters the timing of TNF-?-induced apoptosis. We investigated whether MAPK signaling directly influences TNF-?-induced apoptosis or whether network-level effects secondary to inhibition of the MAPK pathway alter the cellular response. We found that inhibitors of the MAPK kinase kinase Raf, MEK, or extracellular signal-regulated kinase (ERK) exerted distinct effects on the timing and magnitude of TNF-?-induced apoptosis in the mouse intestine. Furthermore, even different MEK inhibitors exerted distinct effects; one, CH5126766, potentiated TNF-?-induced apoptosis, and the others reduced cell death. Computational modeling and experimental perturbation identified the kinase Akt as the primary signaling node that enhanced apoptosis in the context of TNF-? signaling in the presence of CH5126766. Our work emphasizes the importance of integrated network signaling in specifying cellular behavior in response to experimental or therapeutic manipulation. More broadly, this study highlighted the importance of considering the network-level effects of pathway inhibitors and showed the distinct effects of inhibitors that share the same target. PMID:26671150

  8. A Nanoconjugate Apaf-1 Inhibitor Protects Mesothelial Cells from Cytokine-Induced Injury

    PubMed Central

    Santamara, Beatriz; Benito-Martin, Alberto; Ucero, Alvaro Conrado; Aroeira, Luiz Stark; Reyero, Ana; Vicent, Mara Jess; Orzez, Mar; Celdrn, Angel; Esteban, Jaime; Selgas, Rafael; Ruz-Ortega, Marta; Cabrera, Manuel Lpez; Egido, Jess; Prez-Pay, Enrique; Ortiz, Alberto

    2009-01-01

    Background Inflammation may lead to tissue injury. We have studied the modulation of inflammatory milieu-induced tissue injury, as exemplified by the mesothelium. Peritoneal dialysis is complicated by peritonitis episodes that cause loss of mesothelium. Proinflammatory cytokines are increased in the peritoneal cavity during peritonitis episodes. However there is scarce information on the modulation of cell death by combinations of cytokines and on the therapeutic targets to prevent desmesothelization. Methodology Human mesothelial cells were cultured from effluents of stable peritoneal dialysis patients and from omentum of non-dialysis patients. Mesothelial cell death was studied in mice with S. aureus peritonitis and in mice injected with tumor necrosis factor alpha and interferon gamma. Tumor necrosis factor alpha and interferon gamma alone do not induce apoptosis in cultured mesothelial cells. By contrast, the cytokine combination increased the rate of apoptosis 2 to 3-fold over control. Cell death was associated with the activation of caspases and a pancaspase inhibitor prevented apoptosis. Specific caspase-8 and caspase-3 inhibitors were similarly effective. Co-incubation with both cytokines also impaired mesothelial wound healing in an in vitro model. However, inhibition of caspases did not improve wound healing and even impaired the long-term recovery from injury. By contrast, a polymeric nanoconjugate Apaf-1 inhibitor protected from apoptosis and allowed wound healing and long-term recovery. The Apaf-1 inhibitor also protected mesothelial cells from inflammation-induced injury in vivo in mice. Conclusion Cooperation between tumor necrosis factor alpha and interferon gamma contributes to mesothelial injury and impairs the regenerative capacity of the monolayer. Caspase inhibition attenuates mesothelial cell apoptosis but does not facilitate regeneration. A drug targeting Apaf-1 allows protection from apoptosis as well as regeneration in the course of inflammation-induced tissue injury. PMID:19675677

  9. Diverse intracellular pathogens activate Type III Interferon expression from peroxisomes

    PubMed Central

    Odendall, Charlotte; Dixit, Evelyn; Stavru, Fabrizia; Bierne, Helene; Franz, Kate M.; Fiegen, Ann; Boulant, Steeve; Gehrke, Lee; Cossart, Pascale; Kagan, Jonathan C.

    2014-01-01

    Type I Interferon (IFN) responses are considered the primary means by which viral infections are controlled in mammals. Despite this view, several pathogens activate antiviral responses in the absence of Type I IFNs. The mechanisms controlling Type I IFN-independent responses are undefined. We have found that RIG-I like Receptors (RLRs) induce Type III IFN expression in a variety of human cell types, and identified factors that differentially regulate Type I and III IFN expression. We identified peroxisomes as a primary site that initiates Type III IFN expression, and revealed that the process of intestinal epithelial cell differentiation upregulates peroxisome biogenesis and promotes robust Type III IFN responses in human cells. These findings highlight the interconnections between innate immunity and cell biology. PMID:24952503

  10. The STAT3 inhibitor WP1066 reverses the resistance of chronic lymphocytic leukemia cells to histone deacetylase inhibitors induced by interleukin-6.

    PubMed

    Lu, Kang; Fang, Xiao-sheng; Feng, Li-li; Jiang, Yu-jie; Zhou, Xiang-xiang; Liu, Xin; Li, Pei-pei; Chen, Na; Ding, Mei; Wang, Na; Zhang, Jie; Wang, Xin

    2015-04-10

    Interleukin-6 (IL-6) is a pleiotropic cytokine produced by a variety of cell types, including fibroblasts, endothelial cells, lymphocytes, and bone marrow stromal cells (BMSCs). Levels of IL-6 are increased in serum of CLL patients and correlated with adverse clinical features and short survival. In our study, we observed that IL-6 induced the resistance of CLL cells to pan-histone deacetylase (HDAC) inhibitors vorinostat (SAHA) and panobinostat (LBH589). Furthermore, low concentrations of SAHA and LBH589 enhanced the activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway induced by IL-6 in CLL cells. All of these effects were blocked by the STAT3-selective inhibitor, WP1066. Meanwhile, WP1066 decreased the expressions of Mcl-1 and Bcl-xL protein induced by IL-6 with or without low concentrations of HDAC inhibitors. Co-culture of CLL cells with BMSCs could also facilitate the activation of STAT3 and protected CLL cells from apoptosis when treated with HDAC inhibitors, and this cytoprotection was reversed by WP1066. The present study indicated that IL-6 or co-culture with BMSCs prevented HDAC inhibitor-induced apoptosis of CLL cells. This prevention was mediated by activation of the STAT3 signaling pathway. Moreover, WP1066 reversed the resistance of CLL cells to SAHA and LBH589 induced by either IL-6 or co-culture with BMSCs. Our findings suggest that targeting the STAT3 pathway may be a novel way to improve the efficacy of the HDAC inhibitor in CLL patients by overcoming antiapoptotic signaling of the microenvironment. PMID:25636517

  11. Effect of ethylene action inhibitors upon wound-induced gene expression in tomato pericarp

    SciTech Connect

    Henstrand, J.M.; Handa, A.K. )

    1989-09-01

    The contribution of wound-ethylene to wound-induced gene expression was investigated in unripe tomato pericarp using inhibitors of ethylene action. Wounded unripe tomato pericarp was treated with 2,5-norbornadiene or silver thiosulfate to inhibit specifically the induction of ethylene-dependent mRNA species. Poly(A){sup +} RNAs isolated from these tissues after 12 hours of wounding were translated in vitro in a rabbit reticulocyte lysate system and ({sup 35}S)methionine-labeled polypeptides were compared to unwounded controls after separation by one and two-dimensional polyacrylamide gel electrophoresis. Results show that mechanical wounding induces a dramatic shift in gene expression (over 50 mRNA species) but expression of less than 15% of these genes is affected by the treatment with ethylene action inhibitors. A selective decrease in mRNAs coding for a 37 kilodalton doublet and 75 kilodalton polypeptides is observed in 2,5-norbornadiene and silver thiosulfate treated wounded pericarp. Levels of hydroxyproline-rich glycoprotein mRNAs induced in wounded tissue were not influenced by inhibitors of ethylene action.

  12. Serpina1 is a potent inhibitor of IL-8-induced hematopoietic stem cell mobilization

    PubMed Central

    van Pel, Melissa; van Os, Ronald; Velders, Gerjo A.; Hagoort, Henny; Heegaard, Peter M. H.; Lindley, Ivan J. D.; Willemze, Roel; Fibbe, Willem E.

    2006-01-01

    Here, we report that cytokine-induced (granulocyte colony-stimulating factor and IL-8) hematopoietic stem cell (HSC) and hematopoietic progenitor cell (HPC) mobilization is completely inhibited after low-dose (0.5 Gy) total-body irradiation (TBI). Because neutrophil granular proteases are regulatory mediators in cytokine-induced HSC/HPC mobilization, we considered a possible role for protease inhibitors in the induction of HSC/HPC mobilization. Bone marrow (BM) extracellular extracts that were obtained from murine femurs after 0.5 Gy of TBI contained an inhibitor of elastase. Also, after low-dose TBI, both Serpina1 mRNA and protein concentrations were increased in BM extracts, compared with extracts that were obtained from controls. The inhibitory activity in BM extracts of irradiated mice was reversed by addition of an Ab directed against Serpina1. To further study a possible in vivo role of Serpina1 in HSC/HPC mobilization, we administered Serpina1 before IL-8 injection. This administration resulted in an almost complete inhibition of HSC/HPC mobilization, whereas heat-inactivated Serpina1 had no effect. These results indicate that low-dose TBI inhibits cytokine-induced HSC/HPC mobilization and induces Serpina1 in the BM. Because exogenous administration of Serpina1 inhibits mobilization, we propose that radiation-induced Serpina1 is responsible for the inhibition of HSC/HPC mobilization. Also, we hypothesize that cytokine-induced HSC/HPC mobilization is determined by a critical balance between serine proteases and serine protease inhibitors. PMID:16432201

  13. Depressor effect of chymase inhibitor in mice with high salt-induced moderate hypertension.

    PubMed

    Devarajan, Sankar; Yahiro, Eiji; Uehara, Yoshinari; Habe, Shigehisa; Nishiyama, Akira; Miura, Shin-Ichiro; Saku, Keijiro; Urata, Hidenori

    2015-12-01

    The aim of the present study was to determine whether long-term high salt intake in the drinking water induces hypertension in wild-type (WT) mice and whether a chymase inhibitor or other antihypertensive drugs could reverse the increase of blood pressure. Eight-week-old male WT mice were supplied with drinking water containing 2% salt for 12 wk (high-salt group) or high-salt drinking water plus an oral chymase inhibitor (TPC-806) at four different doses (25, 50, 75, or 100 mg/kg), captopril (75 mg/kg), losartan (100 mg/kg), hydrochlorothiazide (3 mg/kg), eplerenone (200 mg/kg), or amlodipine (6 mg/kg). Control groups were given normal water with or without the chymase inhibitor. Blood pressure and heart rate gradually showed a significant increase in the high-salt group, whereas a dose-dependent depressor effect of the chymase inhibitor was observed. There was also partial improvement of hypertension in the losartan- and eplerenone-treated groups but not in the captopril-, hydrochlorothiazide-, and amlodipine-treated groups. A high salt load significantly increased chymase-dependent ANG II-forming activity in the alimentary tract. In addition, the relative contribution of chymase to ANG II formation, but not actual average activity, showed a significant increase in skin and skeletal muscle, whereas angiotensin-converting enzyme-dependent ANG II-forming activity and its relative contribution were reduced by high salt intake. Plasma and urinary renin-angiotensin system components were significantly increased in the high-salt group but were significantly suppressed in the chymase inhibitor-treated group. In conclusion, 2% salt water drinking for 12 wk caused moderate hypertension and activated the renin-angiotensin system in WT mice. A chymase inhibitor suppressed both the elevation of blood pressure and heart rate, indicating a definite involvement of chymase in salt-sensitive hypertension. PMID:26432844

  14. Effects of inhibitors on 1-methyladenine induced maturation of starfish oocytes

    NASA Astrophysics Data System (ADS)

    Lee, Harold H.; Xu, Quanhan

    1986-12-01

    1-methladenine (1-MA) induces starfish oocytes maturation via surface reaction followed by the appearance of a cytoplasmic maturation factor which in turn induces germinal vesicle breakdown (GVBD) to resume meiosis. Cellular mechanisms involved in GVBD were investigated by microinjection of metabolic inhibitors. Colchicine (Co) inhibited maturation, cytochalasin-B (CB) delayed GVBD and actinomycin-D-(Act-D) and puromycin (Pu) had no effect. It appears that the microtubule and the microfilament systems are associated with the nuclear membrane dissolution during the process of oocyte maturation of starfish.

  15. Further studies of auxin and ACC induced feminization in the cucumber plant using ethylene inhibitors

    NASA Technical Reports Server (NTRS)

    Takahashi, H.; Jaffe, M. J.

    1984-01-01

    The present study was designed to establish the role of an essential hormone controlling sex expression in cucumber. A potent anti-ethylene agent, AgNO3, completely inhibited pistillate flower formation caused by IAA, ACC or ethephon. Inhibitors of ethylene biosynthesis, AVG and CoCl2 also suppressed feminization due to exogenous IAA or ACC. Though AVG also suppressed ethephon-induced feminization, this may be due to the second effect of AVG rather than the effect on ACC biosynthesis. These results confirm that ethylene is a major factor regulating feminization and that exogenous auxin induces pistillate flower formation through its stimulation of ethylene production, rather than ACC production.

  16. Nicotinamide phosphoribosyltransferase inhibitor APO866 induces C6 glioblastoma cell death via autophagy.

    PubMed

    Yang, Ping; Zhang, Lu; Shi, Qiao-Juan; Lu, Yun-Bi; Wu, Ming; Wei, Er-Qing; Zhang, Wei-Ping

    2015-10-01

    APO866 is a potent inhibitor of nicotinamide phosphoribosyltransferase (NAMPT), and inhibits nicotinamide adenine dinucleotide (NAD) synthesis. Our previous study showed that APO866 inhibits the proliferation of C6 glioblastoma cells, but failed to induce apoptosis. Since APO866 inhibits cellular metabolism and such metabolic stress is closely related with autophagy, thus we determined whether APO866 can induce autophagy in C6 glioblastoma cells and whether the autophagy induced by APO866 is pro-death or pro-survival. Using LC3 immunofluorescence imaging and transmission electron microscopy detection, we found that APO866 at 1-100 nM induced autophagy in C6 glioblastoma cells. APO866 at 1 nM mainly induced initial autophagic vacuoles. Whereas APO866 at 100 nM induced degrading autophagic vacuoles, as well as induced nuclei malformation and mitochondria swelling. In addition, APO866 concentration-dependently decreased the cell viability of C6 glioblastoma cells, and this effect was attenuated by autophagy inhibitors, including 3-methyladenine and LY294002. APO866 concentration-dependently decreased intracellular NAD level. Interestingly, APO866 at 1 nM slightly decreased intracellular NAD level, but dramatically increased autophagy-positive cells. The dramatical cell viability decreasing required the decreasing of intracellular NAD level to a very low threshold. Thus, our results indicated that APO866 induced pro-death autophagy in C6 glioblastoma cells by decreasing intracellular NAD, and low concentration of APO866 can be used as an autophagy inducer in autophagic-death sensitive glioblastoma. PMID:26601421

  17. Inhibition of peroxisome-proliferator-activated receptor (PPAR)alpha by MK886.

    PubMed Central

    Kehrer, J P; Biswal, S S; La, E; Thuillier, P; Datta, K; Fischer, S M; Vanden Heuvel, J P

    2001-01-01

    Although MK886 was originally identified as an inhibitor of 5-lipoxygenase activating protein (FLAP), recent data demonstrate that this activity does not underlie its ability to induce apoptosis [Datta, Biswal and Kehrer (1999) Biochem. J. 340, 371--375]. Since FLAP is a fatty-acid binding protein, it is conceivable that MK886 may affect other such proteins. A family of nuclear receptors that are activated by fatty acids and their metabolites, the peroxisome-proliferator-activated receptors (PPARs), have been implicated in apoptosis and may represent a target for MK886. The ability of MK886 to inhibit PPAR-alpha, -beta and -gamma activity was assessed using reporter assay systems (peroxisome-proliferator response element--luciferase). Using a transient transfection system in monkey kidney fibroblast CV-1 cells, mouse keratinocyte 308 cells and human lung adenocarcinoma A549 cells, 10--20 microM MK886 inhibited Wy14,643 activation of PPAR alpha by approximately 80%. Similar inhibition of PPAR alpha by MK886 was observed with a stable transfection reporter system in CV-1 cells. Only minimal inhibitory effects were seen on PPAR beta and PPAR gamma. MK886 inhibited PPAR alpha by a non-competitive mechanism as shown by its effects on the binding of arachidonic acid to PPAR alpha protein, and a dose-response study using a transient transfection reporter assay in COS-1 cells. An assay assessing PPAR ligand-receptor interactions showed that MK886 prevents the conformational change necessary for active-complex formation. The expression of keratin-1, a protein encoded by a PPAR alpha-responsive gene, was reduced by MK886 in a culture of mouse primary keratinocytes, suggesting that PPAR inhibition has functional consequences in normal cells. Although Jurkat cells express all PPAR isoforms, various PPAR alpha and PPAR gamma agonists were unable to prevent MK886-induced apoptosis. This is consistent with MK886 functioning as a non-competitive inhibitor of PPAR alpha, but may also indicate that PPAR alpha is not directly involved in MK886-induced apoptosis. Although numerous PPAR activators have been identified, the results show that MK886 can inhibit PPAR alpha, making it the first compound identified to have such an effect. PMID:11389700

  18. Peroxisomal acyl-CoA synthetases

    PubMed Central

    Watkins, Paul A.; Ellis, Jessica M.

    2012-01-01

    Peroxisomes carry out many essential lipid metabolic functions. Nearly all of these functions require that an acyl group either a fatty acid or the acyl side chain of a steroid derivative be thioesterified to coenzyme A (CoA) for subsequent reactions to proceed. This thioesterification, or activation, reaction, catalyzed by enzymes belonging to the acyl-CoA synthetase (ACS) family, is thus central to cellular lipid metabolism. However, despite our rather thorough understanding of peroxisomal metabolic pathways, surprisingly little is known about the specific peroxisomal ACSs that participate in these pathways. Of the 26 ACSs encoded by the human and mouse genomes, only a few have been reported to be peroxisomal, including ACSL4, ACSVL1 (FATP2), and FATP4. In this review, we briefly describe the primary peroxisomal lipid metabolic pathways in which fatty acyl-CoAs participate. Then, we examine the evidence for presence and functions of ACSs in peroxisomes, much of which was obtained before the existence of multiple ACS isoenzymes was known. Finally, we discuss the role(s) of peroxisome-specific ACS isoforms in lipid metabolism. PMID:22366061

  19. Apoptosis and antitumor effects induced by the combination of an mTOR inhibitor and an autophagy inhibitor in human osteosarcoma MG63 cells

    PubMed Central

    HORIE, RYOSUKE; NAKAMURA, OSAMU; YAMAGAMI, YOSHIKI; MORI, MASAKI; NISHIMURA, HIDEKI; FUKUOKA, NATSUKO; YAMAMOTO, TETSUJI

    2016-01-01

    The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway promotes the initiation of autophagy. Although it remains under debate whether chemotherapy-induced autophagy in tumor cells is a protective response or is invoked to promote cell death, recent studies indicate that autophagy is a self-defense mechanism of cancer cells that are subjected to antitumor agents and that blocking autophagy can trigger apoptosis. The aim of this study was to examine the effects of rapamycin, an mTOR inhibitor, on MG63 osteosarcoma cells. We further examined whether the combination of rapamycin and the small molecule inhibitor of autophagy Spautin-1 (specific and potent autophagy inhibitor-1) enhanced the rapamycin-induced apoptosis in MG63 cells. We examined the effects of rapamycin treatment on cell proliferation, phosphorylation of mTOR pathway components, and autophagy by western blot analysis. Furthermore, we examined the effects of rapamycin with or without Spautin-1 on the induction of apoptosis by western blot analysis and immunohistochemical staining. We found that rapamycin inhibited cell proliferation and decreased the phosphorylation of mTOR pathway components in MG63 cells. Rapamycin induced the apoptosis of MG63 cells, and this apoptosis was enhanced by Spautin-1. It was considered that Spautin-1 suppressed the protective mechanism induced by rapamycin in tumor cells and induced apoptosis. Therefore, the combination of an mTOR inhibitor and an autophagy inhibitor may be effective in the treatment of osteosarcoma because it effectively induces the apoptotic pathway. PMID:26530936

  20. Apoptosis and antitumor effects induced by the combination of an mTOR inhibitor and an autophagy inhibitor in human osteosarcoma MG63 cells.

    PubMed

    Horie, Ryosuke; Nakamura, Osamu; Yamagami, Yoshiki; Mori, Masaki; Nishimura, Hideki; Fukuoka, Natsuko; Yamamoto, Tetsuji

    2016-01-01

    The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway promotes the initiation of autophagy. Although it remains under debate whether chemotherapy-induced autophagy in tumor cells is a protective response or is invoked to promote cell death, recent studies indicate that autophagy is a self-defense mechanism of cancer cells that are subjected to antitumor agents and that blocking autophagy can trigger apoptosis. The aim of this study was to examine the effects of rapamycin, an mTOR inhibitor, on MG63 osteosarcoma cells. We further examined whether the combination of rapamycin and the small molecule inhibitor of autophagy Spautin-1 (specific and potent autophagy inhibitor-1) enhanced the rapamycin-induced apoptosis in MG63 cells. We examined the effects of rapamycin treatment on cell proliferation, phosphorylation of mTOR pathway components, and autophagy by western blot analysis. Furthermore, we examined the effects of rapamycin with or without Spautin-1 on the induction of apoptosis by western blot analysis and immunohistochemical staining. We found that rapamycin inhibited cell proliferation and decreased the phosphorylation of mTOR pathway components in MG63 cells. Rapamycin induced the apoptosis of MG63 cells, and this apoptosis was enhanced by Spautin-1. It was considered that Spautin-1 suppressed the protective mechanism induced by rapamycin in tumor cells and induced apoptosis. Therefore, the combination of an mTOR inhibitor and an autophagy inhibitor may be effective in the treatment of osteosarcoma because it effectively induces the apoptotic pathway. PMID:26530936

  1. Cell Death Inducing Microbial Protein Phosphatase Inhibitors--Mechanisms of Action.

    PubMed

    Kleppe, Rune; Herfindal, Lars; Døskeland, Stein Ove

    2015-10-01

    Okadaic acid (OA) and microcystin (MC) as well as several other microbial toxins like nodularin and calyculinA are known as tumor promoters as well as inducers of apoptotic cell death. Their intracellular targets are the major serine/threonine protein phosphatases. This review summarizes mechanisms believed to be responsible for the death induction and tumor promotion with focus on the interdependent production of reactive oxygen species (ROS) and activation of Ca(2+)/calmodulin kinase II (CaM-KII). New data are presented using inhibitors of specific ROS producing enzymes to curb nodularin/MC-induced liver cell (hepatocyte) death. They indicate that enzymes of the arachidonic acid pathway, notably phospholipase A2, 5-lipoxygenase, and cyclooxygenases, may be required for nodularin/MC-induced (and presumably OA-induced) cell death, suggesting new ways to overcome at least some aspects of OA and MC toxicity. PMID:26506362

  2. Peroxisome Biogenesis Disorders: Biological, Clinical and Pathophysiological Perspectives

    ERIC Educational Resources Information Center

    Braverman, Nancy E.; D'Agostino, Maria Daniela; MacLean, Gillian E.

    2013-01-01

    The peroxisome biogenesis disorders (PBD) are a heterogeneous group of autosomal recessive disorders in which peroxisome assembly is impaired, leading to multiple peroxisome enzyme deficiencies, complex developmental sequelae and progressive disabilities. Mammalian peroxisome assembly involves the protein products of 16 "PEX" genes;

  3. Peroxisome Biogenesis Disorders: Biological, Clinical and Pathophysiological Perspectives

    ERIC Educational Resources Information Center

    Braverman, Nancy E.; D'Agostino, Maria Daniela; MacLean, Gillian E.

    2013-01-01

    The peroxisome biogenesis disorders (PBD) are a heterogeneous group of autosomal recessive disorders in which peroxisome assembly is impaired, leading to multiple peroxisome enzyme deficiencies, complex developmental sequelae and progressive disabilities. Mammalian peroxisome assembly involves the protein products of 16 "PEX" genes;…

  4. T0070907, a PPAR ? Inhibitor, Induced G2/M Arrest Enhances the Effect of Radiation in Human Cervical Cancer Cells Through Mitotic Catastrophe

    PubMed Central

    An, Zhengzhe; Muthusami, Sridhar; Yu, Jae-Ran

    2014-01-01

    Overexpression of peroxisome proliferator activator receptor ? (PPAR?) has been implicated in many types of cancer including cervical cancer. Radiation therapy remains the main nonsurgical modality for the treatment of cervical cancer. The present study reports the impact of pharmacological inhibition of PPAR? in enhancing the radiosensitization of cervical cancer cells in vitro. Three cervical cancer cell lines (HeLa, SiHa, and Me180) were treated with a PPAR? inhibitor, T0070907, and/or radiation. The changes in protein, cell cycle, DNA content, apoptosis, and cell survival were analyzed. The PPAR? is differentially expressed in cervical cancer cells with maximum expression in ME180 cells. T0070907 has significantly decreased the tubulin levels in a time-dependent manner in ME180 cells. The decrease in the tubulin levels after T0070907 in ME180 and SiHa cells was associated with significant increase in the cells at the G2/M phase. The changes in the tubulin and G2/M phase were not evident in HeLa cells. T0070907 reduced the protein levels of PPAR?; however, PPAR? silencing had no effect on the ?-tubulin level in ME180 cells suggesting the PPAR?-dependent and -independent actions of T0070907. To ascertain the impact of synergistic effect of T0070907 and radiation, HeLa and ME180 cells were pretreated with T0070907 and subjected to radiation (4 Gy). Annexin V-fluorescein isothiocyanate analysis revealed increased apoptosis in cells treated with radiation and T0070907 when compared to control and individual treatment. In addition, T0070907 pretreatment enhanced radiation-induced tetraploidization reinforcing the additive effect of T0070907. Confocal analysis of tubulin confirmed the onset of mitotic catastrophe in cells treated with T0070907 and radiation. These results strongly suggest the radiosensitizing effects of T0070907 through G2/M arrest and mitotic catastrophe. PMID:24642720

  5. Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

    SciTech Connect

    Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

    2010-07-23

    Research highlights: {yields} Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma}. {yields} GW9662 treatment alone increased RAGE mRNA levels in tubular cells. {yields} Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-{beta} gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression via PPAR{gamma} activation.

  6. Electron transport chain inhibitors induce microglia activation through enhancing mitochondrial reactive oxygen species production.

    PubMed

    Ye, Junli; Jiang, Zhongxin; Chen, Xuehong; Liu, Mengyang; Li, Jing; Liu, Na

    2016-01-15

    Reactive oxygen species (ROS) are believed to be mediators of excessive microglial activation, yet the resources and mechanism are not fully understood. Here we stimulated murine microglial BV-2 cells and primary microglial cells with different inhibitors of electron transport chain (ETC), rotenone, thenoyltrifluoroacetone (TTFA), antimycin A, and NaN3 to induce mitochondrial ROS production and we observed the role of mitochondrial ROS in microglial activation. Our results showed that ETC inhibitors resulted in significant changes in cell viability, microglial morphology, cell cycle arrest and mitochondrial ROS production in a dose-dependent manner in both primary cultural microglia and BV-2 cell lines. Moreover, ETC inhibitors, especially rotenone and antimycin A stimulated secretion of interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) by microglia with marked activation of mitogen-activated proteinkinases (MAPKs) and nuclear factor κB (NF-κB), which could be blocked by specific inhibitors of MAPK and NF-κB and mitochondrial antioxidants, Mito-TEMPO. Taken together, our results demonstrated that inhibition of mitochondrial respiratory chain in microglia led to production of mitochondrial ROS and therefore may activate MAPK/NF-кB dependent inflammatory cytokines release in microglia, which indicated that mitochondrial-derived ROS were contributed to microglial activation. PMID:26511505

  7. Mitochondrial Complex I Inhibitors and Forced Oxidative Phosphorylation Synergize in Inducing Cancer Cell Death

    PubMed Central

    Simonetto, Tiziana; Chiaradonna, Ferdinando

    2013-01-01

    Cancer cells generally rely mostly on glycolysis rather than oxidative phosphorylation (OXPHOS) for ATP production. In fact, they are particularly sensitive to glycolysis inhibition and glucose depletion. On the other hand mitochondrial dysfunctions, involved in the onset of the Warburg effect, are sometimes also associated with the resistance to apoptosis that characterizes cancer cells. Therefore, combined treatments targeting both glycolysis and mitochondria function, exploiting peculiar tumor features, might be lethal for cancer cells. In this study, we show that glucose deprivation and mitochondrial Complex I inhibitors synergize in inducing cancer cell death. In particular, our results reveal that low doses of Complex I inhibitors, ineffective on immortalized cells and in high glucose growth, become specifically cytotoxic on cancer cells deprived of glucose. Importantly, the cytotoxic effect of the inhibitors on cancer cells is strongly enhanced by forskolin, a PKA pathway activator, that we have previously shown to stimulate OXPHOS. Taken together, we demonstrate that induction in cancer cells of a switch from a glycolytic to a more respirative metabolism, obtained by glucose depletion or mitochondrial activity stimulation, strongly increases their sensitivity to low doses of mitochondrial Complex I inhibitors. Our findings might be a valuable approach to eradicate cancer cells. PMID:23690779

  8. Methods for the Analyses of Inhibitor-Induced Aberrant Multimerization of HIV-1 Integrase

    PubMed Central

    Kessl, Jacques J.; Sharma, Amit; Kvaratskhelia, Mamuka

    2016-01-01

    HIV-1 integrase (IN) is an important therapeutic target as its function is essential for the viral lifecycle. The discovery of multifunctional allosteric IN inhibitors or ALLINIs, which potently impair viral replication by promoting aberrant, higher order IN multimerization as well as inhibit IN interactions with its cellular cofactor, LEDGF/p75, has opened new venues to exploit IN multimerization as a therapeutic target. Furthermore, the recent discovery of multimerization selective IN inhibitors or MINIs, has provided new investigational probes to study the direct effects of aberrant IN multimerization in vitro and in infected cells. Here we describe three complementary methods designed to detect and quantify the effects of these new classes of inhibitors on IN multimerization. These methods include a homogenous time-resolved fluorescence-based assay which allows for measuring EC50 values for the inhibitor-induced aberrant IN multimerization, a dynamic light scattering-based assay which allows for monitoring the formation and sizes of oligomeric IN particles in a time-dependent manner, and a chemical cross-linking-based assay of interacting IN subunits which allows for the determination of IN oligomers in viral particles. PMID:26714710

  9. Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

    PubMed Central

    Nishizawa, Toshihiro; Suzuki, Hidekazu; Kanai, Takanori; Yahagi, Naohisa

    2015-01-01

    Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.573.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy. PMID:25759512

  10. NPI-0052, a novel proteasome inhibitor, induces caspase-8 and ROS-dependent apoptosis alone and in combination with HDAC inhibitors in leukemia cells.

    PubMed

    Miller, Claudia P; Ban, Kechen; Dujka, Melanie E; McConkey, David J; Munsell, Mark; Palladino, Michael; Chandra, Joya

    2007-07-01

    The proteasome has been successfully targeted for the treatment of multiple myeloma and mantle cell lymphoma; however, in other hematologic malignancies, bortezomib has been less effective as a single agent. Here, we describe effects of NPI-0052, a novel proteasome inhibitor, in leukemia model systems. In cell lines, NPI-0052 inhibits all 3 proteolytic activities associated with the proteasome: chymotrypsin-, trypsin-, and caspase-like. NPI-0052 also induces DNA fragmentation in leukemia lines and in mononuclear cells from a Ph + acute lymphoblastic leukemia (ALL) patient. Caspase-3 activation by NPI-0052 was seen in wild-type Jurkat cells, but was significantly lessened in Fas-associated death domain (FADD)-deficient or caspase-8-deficient counterparts. NPI-0052-induced apoptosis was further probed using caspase-8 inhibitors, which were more protective than caspase-9 inhibitors. N-acetyl cysteine (NAC) also conferred protection against NPI-0052-induced apoptosis, indicating a role for oxidative stress by NPI-0052. In support of the drug's in vitro activities, biweekly treatment with NPI-0052 lessened total white blood cell (WBC) burden over 35 days in leukemic mice. Interestingly, combining NPI-0052 with either MS-275 or valproic acid (VPA) induced greater levels of cell death than the combination of bortezomib with these histone deacetylase inhibitors (HDACi). These effects of NPI-0052, alone and in combination with HDACi, warrant further testing to determine the compound's clinical efficacy in leukemia. PMID:17356134

  11. Peroxisomal Import Reduces the Proapoptotic Activity of Deubiquitinating Enzyme USP2

    PubMed Central

    Reglinski, Katharina; Keil, Marina; Altendorf, Sabrina; Waithe, Dominic; Eggeling, Christian; Schliebs, Wolfgang; Erdmann, Ralf

    2015-01-01

    The human deubiquitinating enzyme ubiquitin-specific protease 2 (USP2) regulates multiple cellular pathways, including cell proliferation and apoptosis. As a result of alternative splicing four USP2 isoenzymes are expressed in human cells of which all contain a weak peroxisome targeting signal of type 1 (PTS1) at their C-termini. Here, we systematically analyzed apoptotic effects induced by overexpression and intracellular localization for each isoform. All isoforms exhibit proapoptotic activity and are post-translationally imported into the matrix of peroxisomes in a PEX5-dependent manner. However, a significant fraction of the USP2 pool resides in the cytosol due to a weaker PTS1 and thus low affinity to the PTS receptor PEX5. Blocking of peroxisomal import did not interfere with the proapoptotic activity of USP2, suggesting that the enzyme performs its critical function outside of this compartment. Instead, increase of the efficiency of USP2 import into peroxisomes either by optimization of its peroxisomal targeting signal or by overexpression of the PTS1 receptor did result in a reduction of the apoptotic rate of transfected cells. Our studies suggest that peroxisomal import of USP2 provides additional control over the proapoptotic activity of cytosolic USP2 by spatial separation of the deubiquitinating enzymes from their interaction partners in the cytosol and nucleus. PMID:26484888

  12. The role of peroxisomal fatty acyl-CoA beta-oxidation in bile acid biosynthesis

    SciTech Connect

    Hayashi, H.; Miwa, A. )

    1989-11-01

    The physiological role of the peroxisomal fatty acyl-CoA beta-oxidizing system (FAOS) is not yet established. We speculated that there might be a relationship between peroxisomal degradation of long-chain fatty acids in the liver and the biosynthesis of bile acids. This was investigated using (1-{sup 14}C)butyric acid and (1-{sup 14}C)lignoceric acid as substrates of FAOS in mitochondria and peroxisomes, respectively. The incorporation of ({sup 14}C)lignoceric acid into primary bile acids was approximately four times higher than that of ({sup 14}C)butyric acid (in terms of C-2 units). The pools of these two fatty acids in the liver were exceedingly small. The incorporations of radioactivity into the primary bile acids were strongly inhibited by administration of aminotriazole, which is a specific inhibitor of peroxisomal FAOS in vivo. Aminotriazole inhibited preferentially the formation of cholate, the major primary bile acid, from both ({sup 14}C)lignoceric acid and ({sup 14}C)butyric acid, rather than the formation of chenodeoxycholate. The former inhibition was about 70% and the latter was approximately 40-50%. In view of reports that cholate is biosynthesized from endogenous cholesterol, the above results indicate that peroxisomal FAOS may have an anabolic function, supplying acetyl CoA for bile acid biosynthesis.

  13. Chronic activation of peroxisome proliferator-activated receptor-alpha with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activat...

  14. Calpain Inhibitor PD150606 Attenuates Glutamate Induced Spiral Ganglion Neuron Apoptosis through Apoptosis Inducing Factor Pathway In Vitro

    PubMed Central

    Song, Yong-Li; Chen, Xiao-Dong; Mi, Wen-Juan; Wang, Jian; Lin, Ying; Chen, Fu-Quan; Qiu, Jian-Hua

    2015-01-01

    Objective This research aimed to investigate whether glutamate induced spiral ganglion neurons (SGNs) apoptosis through apoptosis inducing factor (AIF) pathway. And verify whether PD150606, a calpain inhibitor could prevent apoptosis by inhibiting cleaving and releasing AIF in mitochondrion. Methods SGNs of postnatal days 0-3 were harvested and cultured in dishes. 20 mM Glu, the caspase inhibitor Z-VAD-FMK and calpain inhibitor PD150606 were added into cultured dishes separately. We used optical microscope and immunofluoresence staining to observe cell morphology and AIF distribution, RT-PCR and Westernblot to analyse AIF and calpain expression in SGNs. TUNEL assay was used to test cell apoptosis. Results Cell morphology and nuclear translocation of AIF were altered in SGNs by 20 mM Glu treated in vitro. The axon of SGN shortened, more apoptosis SGN were observed and the expression of AIF and calpain were up-regulated in Glu-treated group than the normal one (P<0.05). The same experiments were conducted in 20 mM+PD150606 treated group and 20 mM+Z-VAD-FMK group. Obviously AIF were located from cytoplasm to the nuclear and the expressions of AIF and calpain were down-regulated by PD150606 (P<0.05). Positive cells in TUNEL staining decreased after PD150606 treating. However, Z-VAD-FMK had no influence on AIF, calpain expression or cell apoptosis. Conclusion The AIF-related apoptosis pathway is involved in the process of Glu-induced SGN injury. Furthermore, the inhibition of calpain can prevent AIF from releasing the nuclear or inducing SGN apoptosis. PMID:25874633

  15. HSP90 inhibitor CH5164840 induces micronuclei in TK6 cells via an aneugenic mechanism.

    PubMed

    Matsuzaki, Kaori; Harada, Asako; Tanaka, Kenji; Takeiri, Akira; Mishima, Masayuki

    2014-10-01

    Heat-shock protein 90 (HSP90) is a promising druggable target for therapy of conditions including cancer, renal disease, and chronic neurodegenerative diseases. Despite the possible beneficial effects of HSP90 inhibitors, some of these agents present a genotoxicity liability. We have examined the mode of action of micronucleus formation in TK6 cells by a novel and highly specific HSP90 inhibitor, CH5164840, by means of an in vitro micronucleus test with fluorescence in situ hybridization (FISH), ?H2AX staining to detect DNA damage, and microscopic observation of chromosomal alignment in mitotic cells. The percentage of centromere-positive micronuclei induced by CH5164840 (FISH analysis) was significant, but the percentage of centromere-negative ones was not, suggesting that induction of micronuclei was due to a mechanism of aneugenicity rather than DNA reactivity. This conclusion was further supported by the result of co-staining ?H2AX and the apoptosis marker caspase-3; the predominant elevation of apoptotic ?H2AX rather than non-apoptotic ?H2AX indicated little involvement of DNA-reactivity mechanisms. Microscopic observation revealed asymmetric spindle microtubules and chromosomal misalignment of metaphase cells. These data indicated that CH5164840 causes spindle dysfunction that induces micronuclei. The risk/benefit ratio must be considered in the development of HSP90 inhibitors. PMID:25308700

  16. CTA095, a Novel Etk and Src Dual Inhibitor, Induces Apoptosis in Prostate Cancer Cells and Overcomes Resistance to Src Inhibitors

    PubMed Central

    Guo, Wenchang; Liu, Ruiwu; Bhardwaj, Gaurav; Ma, Ai-Hong; Changou, Chun; Yang, Joy C.; Li, Yuanpei; Feng, Caihong; Luo, Yan; Mazloom, Anisha; Sanchez, Eduardo; Wang, Yan; Huang, Wenzhe; Patterson, Randen; Evans, Christopher P.; Lam, Kit S.; Kung, Hsing-Jien

    2013-01-01

    Etk is a non-receptor tyrosine kinase, which provides a strong survival signal in human prostate cancer cells. Src, another tyrosine kinase that cross-activates with Etk, has been shown to play an important role in prostate cancer metastasis. Herein, we discovered a new class of Etk inhibitors. Within those inhibitors, CTA095 was identified as a potent Etk and Src dual inhibitor. CTA095 was found to induce autophagy as well as apoptosis in human prostate cancer cells. In addition, CTA095 inhibited HUVEC cell tube formation and wound healing of human prostate cancer cells, implying its role in inhibition of angiogenesis and metastasis of human prostate cancer. More interestingly, CTA095 could overcome Src inhibitor resistance in prostate cancer cells. It induces apoptosis in Src inhibitor resistant prostate cancer cells, likely through a mechanism of down regulation of Myc and BCL2. This finding indicates that simultaneously targeting Etk and Src could be a promising approach to overcome drug resistance in prostate cancer. PMID:23967135

  17. Antagonism between granulocytic maturation and deacetylase inhibitor-induced apoptosis in acute promyelocytic leukaemia cells

    PubMed Central

    Hennig, D; Müller, S; Wichmann, C; Drube, S; Pietschmann, K; Pelzl, L; Grez, M; Bug, G; Heinzel, T; Krämer, O H

    2015-01-01

    Background: Transcriptional repression is a key mechanism driving leukaemogenesis. In acute promyelocytic leukaemia (APL), the fusion protein promyelocytic leukaemia-retinoic acid receptor-α fusion (PML-RARα) recruits transcriptional repressors to myeloid differentiation genes. All-trans-retinoic acid (ATRA) induces the proteasomal degradation of PML-RARα and granulocytic differentiation. Histone deacetylases (HDACs) fall into four classes (I–IV) and contribute to the transcription block caused by PML-RARα. Methods: Immunoblot, flow cytometry, and May-Grünwald–Giemsa staining were used to analyze differentiation and induction of apoptosis. Results: A PML-RARα- and ATRA-dependent differentiation programme induces granulocytic maturation associated with an accumulation of the myeloid transcription factor CCAAT/enhancer binding protein (C/EBP)ɛ and of the surface protein CD11b. While this process protects APL cells from inhibitors of class I HDAC activity, inhibition of all Zinc-dependent HDACs (classes I, II, and IV) with the pan-HDACi (histone deacetylase inhibitor(s)) LBH589 induces apoptosis of immature and differentiated APL cells. LBH589 can eliminate C/EBPɛ and the mitochondrial apoptosis regulator B-cell lymphoma (BCL)-xL in immature and differentiated NB4 cells. Thus, BCL-xL and C/EBPɛ are newly identified molecular markers for the efficacy of HDACi against APL cells. Conclusions: Our results could explain the therapeutic limitations occurring with ATRA and class I HDACi combinations. Pro-apoptotic effects caused by pan-HDAC inhibition are not blunted by ATRA-induced differentiation and may provide a clinically interesting alternative. PMID:25514379

  18. Suppression of VEGF-induced angiogenesis by the protein tyrosine kinase inhibitor, lavendustin A.

    PubMed Central

    Hu, D E; Fan, T P

    1995-01-01

    1. Vascular endothelial growth factor (VEGF) is a heparin-binding angiogenic factor which specifically acts on endothelial cells via distinct membrane-spanning tyrosine kinase receptors. Here we used the rat sponge implant model to test the hypothesis that the angiogenic activity of VEGF can be suppressed by protein tyrosine kinase (PTK) inhibitors. 2. Neovascular responses in subcutaneous sponge implants were determined by measurements of relative sponge blood flow by use of a 133Xe clearance technique, and confirmed by histological studies and morphometric analysis. 3. Daily local administration of 250 ng VEGF165 accelerated the rate of 133Xe clearance from the sponges and induced an intense neovascularisation. This VEGF165-induced angiogenesis was inhibited by daily co-administration of the selective PTK inhibitor, lavendustin A (10 micrograms), but not its negative control, lavendustin B (10 micrograms). Blood flow measurements and morphometric analysis of 8-day-old sponges showed that lavendustin A reduced the 133Xe clearance of VEGF165-treated sponges from 32.9 +/- 1.5% to 20.9 +/- 1.6% and the total fibrovascular growth area from 62.4 +/- 6.1% to 21.6 +/- 6.8% (n = 12, P < 0.05). 4. Co-injection of suramin (3 mg), an inhibitor of heparin-binding growth factors, also suppressed the VEGF165-elicited neovascular response. In contrast, neither lavendustin A nor suramin produced any effect on the basal sponge-induced angiogenesis. 5. When given alone, low doses of VEGF165 (25 ng) or basic fibroblast growth factor (bFGF; 10 ng) did not modify the basal sponge-induced neovascularisation.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 2 Figure 2 PMID:7533611

  19. Valproic acid defines a novel class of HDAC inhibitors inducing differentiation of transformed cells

    PubMed Central

    Gttlicher, Martin; Minucci, Saverio; Zhu, Ping; Krmer, Oliver H.; Schimpf, Annemarie; Giavara, Sabrina; Sleeman, Jonathan P.; Lo Coco, Francesco; Nervi, Clara; Pelicci, Pier Giuseppe; Heinzel, Thorsten

    2001-01-01

    Histone deacetylases (HDACs) play important roles in transcriptional regulation and pathogenesis of cancer. Thus, HDAC inhibitors are candidate drugs for differentiation therapy of cancer. Here, we show that the well-tolerated antiepileptic drug valproic acid is a powerful HDAC inhibitor. Valproic acid relieves HDAC-dependent transcriptional repression and causes hyperacetylation of histones in cultured cells and in vivo. Valproic acid inhibits HDAC activity in vitro, most probably by binding to the catalytic center of HDACs. Most importantly, valproic acid induces differentiation of carcinoma cells, transformed hematopoietic progenitor cells and leukemic blasts from acute myeloid leukemia patients. More over, tumor growth and metastasis formation are significantly reduced in animal experiments. Therefore, valproic acid might serve as an effective drug for cancer therapy. PMID:11742974

  20. Angiogenesis inhibitor DC101 delays growth of intracerebral glioblastoma but induces morbidity when combined with irradiation.

    PubMed

    Verhoeff, Joost J C; Stalpers, Lukas J A; Van Noorden, Cornelis J F; Troost, Dirk; Ramkema, Marja D; van Bree, Chris; Song, Ji-Ying; Donker, Mila; Chekenya, Martha; Vandertop, W Peter; Richel, Dick J; van Furth, Wouter R

    2009-11-18

    The combination of irradiation with angiogenic inhibition is increasingly being investigated for treatment of glioblastoma multiforme (GBM). We investigated whether vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitor DC101 affects morbidity and tumor growth in irradiated and non-irradiated intracerebral GBM-bearing mice, controlled with sham treatments. End-points were toxicity, morbidity and histology. Irradiation either or not combined, reduced tumor size strongly, whereas DC101 mono-treatment reduced tumor size by 64%. Irradiation delayed morbidity from 5.8 weeks in sham-treated mice to 10.3 weeks. Morbidity after combined treatment occurred after 5.9 weeks. Treatment with angiogenesis inhibitor DC101 delays tumor growth but it induces morbidity, by itself or combined with irradiation. PMID:19473756

  1. Risk assessment and management of anthracycline and HER2 receptor inhibitor-induced cardiomyopathy.

    PubMed

    Jahangir, Eiman; Shah, Sangeeta; Shum, Kelly; Baxter, Caitlin; Fitzpatrick, Jill D; Cole, John; Gilliland, Yvonne; Polin, Nichole M

    2015-02-01

    With the advent and increased use of chemotherapeutic agents and radiation therapy, cancer survival rates have increased. With increased survival, both acute and chronic cardiotoxic adverse effects have emerged. The growing need for managing the treatment of individuals with chemotherapy-induced cardiotoxicity has led to the formation of cardio-oncology programs throughout the United States. These programs concentrate on many aspects of cardiac disease in the oncology patient. Of these, the cardiotoxic effects (particularly cardiomyopathy) of anthracyclines and HER2 receptor inhibitors are a large focus of cardio-oncology practice. Despite the increasing availability of these programs, no consensus guidelines have been established to provide a framework for treating these patients. This review describes the initial evaluation, risk assessment, and management of individuals receiving anthracycline and HER2 receptor inhibitor therapy for cardiomyopathy. These recommendations are supported by the current literature in this field. PMID:25688890

  2. Hypoxia inducible factor 1? expression and effects of its inhibitors in canine lymphoma

    PubMed Central

    KAMBAYASHI, Satoshi; IGASE, Masaya; KOBAYASHI, Kosuke; KIMURA, Ayana; SHIMOKAWA MIYAMA, Takako; BABA, Kenji; NOGUCHI, Shunsuke; MIZUNO, Takuya; OKUDA, Masaru

    2015-01-01

    Hypoxic conditions in various cancers are believed to relate with their malignancy, and hypoxia inducible factor-1? (HIF-1?) has been shown to be a major regulator of the response to low oxygen. In this study, we examined HIF-1? expression in canine lymphoma using cell lines and clinical samples and found that these cells expressed HIF-1?. Moreover, the HIF-1? inhibitors, echinomycin, YC-1 and 2-methoxyestradiol, suppressed the proliferation of canine lymphoma cell lines. In a xenograft model using NOD/scid mice, echinomycin treatment resulted in a dose-dependent regression of the tumor. Our results suggest that HIF-1? contributes to the proliferation and/or survival of canine lymphoma cells. Therefore, HIF-1? inhibitors may be potential agents to treat canine lymphoma. PMID:26050843

  3. Endocrinopathies induced by immune-checkpoint inhibitors in advanced non-small cell lung cancer.

    PubMed

    Rossi, Emanuela; Sgambato, Assunta; De Chiara, Giovanni; Casaluce, Francesca; Losanno, Tania; Sacco, Paola Claudia; Santabarbara, Giuseppe; Gridelli, Cesare

    2016-03-01

    The advent of immunotherapy has recently expanded the therapeutic options in advanced non-small cell lung cancer (NSCLC). In these patients, the recent efficacy demonstration of antibodies against immune checkpoints: the anti-programmed death-1 (PD-1) and anti-programmed death ligand-1 (PD-L1), has led to approval of nivolumab and pembrolizumab (anti-PD-1) in the treatment of advanced NSCLC. The mechanism of action of checkpoint inhibitors explains the development of autoimmune diseases as a side-effect of these medications. Among these, a spectrum of endocrine disorders has been also reported. This manuscript focuses particularly on endocrine disorders induced by immuno-checkpoint inhibitors employed in NSCLC, in order to suggest the strategies for their diagnosis and effective management. PMID:26681547

  4. Proteasome inhibitor-induced autophagy in PC12 cells overexpressing A53T mutant ?-synuclein.

    PubMed

    Lan, Danmei; Wang, Wenzhao; Zhuang, Jianhua; Zhao, Zhongxin

    2015-03-01

    The aim of the present study was to examine the effects of proteasome inhibitor (PI)?induced autophagy on PC12 cells overexpressing A53T mutant ??synuclein (??syn) by detecting alterations in the levels of microtubule?associated protein 1A/1B light chain (LC3)+ autophagosomes and the lysotracker?positive autolysosomes using immunofluorescence, the expression of LC3?II using western blot analysis and the morphology of PC12 cells using transmission electron microscopy. It was found that the addition of MG132 (500 nmol/l) significantly increased the number of autophagosomes and autolysosomes and upregulated the expression of LC3?II. The autophagy inhibitor 3?methyladenine (3?MA) completely inhibited the autophagy induced by MG132 (500 nmol/l). The autophagy enhancer trehalose significantly increased the number of autophagosomes and autolysosomes and improved the protein level of LC3?II induced by MG132. To examine the effect of PI?induced autophagy on the degradation of A53T mutant ??syn, the expression of ??syn was detected by western blot analysis. It was revealed that MG132 increased the expression of A53T ??syn and trehalose counteracted the increase of A53T ??syn induced by MG132. Combined inhibition of 3?MA and PI significantly increased the accumulation of A53T ??syn as compared with treatment using either single agent. In addition, combination of MG132 (500 nmol/l) with trehalose (50 mmol/l) or 3?MA (2 mmol/l) markedly decreased the cell viability as compared with treatment using either single agent individually as demonstrated using a 3?(4,5?dimethylthiazol?2?yl)?2,5?diphenyltetrazolium bromide assay. These results suggest that the PI, MG132, could induce autophagy in PC12 cells overexpressing A53T mutant ??syn and this autophagy could be completely inhibited by 3?MA, indicating that PI?induced autophagy is mediated by the upregulation of the macroautophagy class III PI3K pathway. PI?induced autophagy may act as a compensatory degradation system for degradation of A53T ??syn when the ubiquitin?proteasome system is impaired. Autophagy activation may directly contribute to the survival of PC12 cells treated with proteasome inhibitors. The present study may assist in illuminating the association between PI and autophagy in the pathogenesis of Parkinson's disease. PMID:25434876

  5. p53 modulates the AMPK inhibitor compound C induced apoptosis in human skin cancer cells

    SciTech Connect

    Huang, Shi-Wei; Wu, Chun-Ying; Wang, Yen-Ting; Kao, Jun-Kai; Lin, Chi-Chen; Chang, Chia-Che; Mu, Szu-Wei; Chen, Yu-Yu; Chiu, Husan-Wen; Chang, Chuan-Hsun; Liang, Shu-Mei; Chen, Yi-Ju; Huang, Jau-Ling; Shieh, Jeng-Jer

    2013-02-15

    Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status. - Highlights: ► Compound C caused more apoptosis in p53 wildtype than p53-mutant skin cancer cells. ► Compound C can upregulate p53 expression and induce p53 activation. ► Compound C induced p53 effects were dependent on ROS induced DNA damage pathway. ► p53-knockdown attenuated compound C-induced apoptosis but not autophagy. ► Compound C-induced apoptosis in skin cancer cells was dependent on p53 status.

  6. Angiotensin II induces secretion of plasminogen activator inhibitor 1 and a tissue metalloprotease inhibitor-related protein from rat brain astrocytes

    SciTech Connect

    Olson, J.A. Jr.; Shiverick, K.T.; Ogilvie, S.; Buhi, W.C.; Raizada, M.K. )

    1991-03-01

    The present study investigates angiotensin (Ang) II effects on secretory protein synthesis in brain astrocytes cultured from neonatal and 21-day-old rats. Ang II-induced changes in the de novo synthesis of (35S)methionine-labeled secretory proteins were visualized using two-dimensional NaDodSO4/PAGE. Astrocytes from 21-day-old rat brain possess specific high-affinity receptors for Ang II. These cells express two Ang II-induced secretory proteins with Mr 55,000 (AISP-55K) and Mr 30,000 (AISP-30K), which were time- and dose-dependent (EC50, 1 nM). (Sar1, Ile8)Ang II (where Sar is sarcosine) inhibited Ang II-induced secretion of AISP-55K but not AISP-30K. N-terminal amino acid sequencing indicates that AISP-55K is identical to rat plasminogen activator inhibitor 1, whereas AISP-30K exhibits 72-81% identity to three closely related proteins: human tissue inhibitor of metalloproteases, a rat phorbol ester-induced protein, and the murine growth-responsive protein 16C8. Immunofluorescent staining with rat plasminogen activator inhibitor 1 antibody was induced in the majority of cells in culture after Ang II treatment of astrocytes from 21-day-old rat brains. Absence of this response to Ang II in astrocytes from neonatal rat brain provides evidence that this action of Ang II on astrocytes is developmentally regulated.

  7. Nonhypoxic regulation and role of hypoxia-inducible factor 1 in aromatase inhibitor resistant breast cancer

    PubMed Central

    2014-01-01

    Introduction Although aromatase inhibitors (AIs; for example, letrozole) are highly effective in treating estrogen receptor positive (ER+) breast cancer, a significant percentage of patients either do not respond to AIs or become resistant to them. Previous studies suggest that acquired resistance to AIs involves a switch from dependence on ER signaling to dependence on growth factor-mediated pathways, such as human epidermal growth factor receptor-2 (HER2). However, the role of HER2, and the identity of other relevant factors that may be used as biomarkers or therapeutic targets remain unknown. This study investigated the potential role of transcription factor hypoxia inducible factor 1 (HIF-1) in acquired AI resistance, and its regulation by HER2. Methods In vitro studies using AI (letrozole or exemestane)-resistant and AI-sensitive cells were conducted to investigate the regulation and role of HIF-1 in AI resistance. Western blot and RT-PCR analyses were conducted to compare protein and mRNA expression, respectively, of ER?, HER2, and HIF-1? (inducible HIF-1 subunit) in AI-resistant versus AI-sensitive cells. Similar expression analyses were also done, along with chromatin immunoprecipitation (ChIP), to identify previously known HIF-1 target genes, such as breast cancer resistance protein (BCRP), that may also play a role in AI resistance. Letrozole-resistant cells were treated with inhibitors to HER2, kinase pathways, and ER? to elucidate the regulation of HIF-1 and BCRP. Lastly, cells were treated with inhibitors or inducers of HIF-1? to determine its importance. Results Basal HIF-1? protein and BCRP mRNA and protein are higher in AI-resistant and HER2-transfected cells than in AI-sensitive, HER2- parental cells under nonhypoxic conditions. HIF-1? expression in AI-resistant cells is likely regulated by HER2 activated-phosphatidylinositide-3-kinase/Akt-protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway, as its expression was inhibited by HER2 inhibitors and kinase pathway inhibitors. Inhibition or upregulation of HIF-1? affects breast cancer cell expression of BCRP; AI responsiveness; and expression of cancer stem cell characteristics, partially through BCRP. Conclusions One of the mechanisms of AI resistance may be through regulation of nonhypoxic HIF-1 target genes, such as BCRP, implicated in chemoresistance. Thus, HIF-1 should be explored further for its potential as a biomarker of and therapeutic target. PMID:24472707

  8. Expression of latent HIV induced by the potent HDAC inhibitor suberoylanilide hydroxamic acid.

    PubMed

    Archin, Nancie M; Espeseth, Amy; Parker, Daniel; Cheema, Manzoor; Hazuda, Daria; Margolis, David M

    2009-02-01

    Histone deacetylases (HDACs) act on histones within the nucleosome-bound promoter of human immunodeficiency virus type 1 (HIV-1) to maintain proviral latency. HDAC inhibition leads to promoter expression and the escape of HIV from latency. We evaluated the ability of the potent inhibitor recently licensed for use in oncology, suberoylanilide hydroxamic acid (SAHA; Vorinostat), selective for Class I HDACs, to induce HIV promoter expression in cell lines and virus production from the resting CD4(+) T cells of antiretroviral-treated, aviremic HIV-infected patients. In J89, a Jurkat T cell line infected with a single HIV genome encoding the enhanced green fluorescence protein (EGFP) within the HIV genome, SAHA induced changes at nucleosome 1 of the HIV promoter in chromatin immunoprecipitation (ChIP) assays in concert with EGFP expression. In the resting CD4(+) T cells of antiretroviral-treated, aviremic HIV-infected patients clinically achievable exposures to SAHA induced virus outgrowth ex vivo. These results suggest that potent, selective HDAC inhibitors may allow improved targeting of persistent proviral HIV infection, and define parameters for in vivo studies using SAHA. PMID:19239360

  9. Mitochondrial division inhibitor-1 induces mitochondrial hyperfusion and sensitizes human cancer cells to TRAIL-induced apoptosis.

    PubMed

    Akita, Mamoru; Suzuki-Karasaki, Miki; Fujiwara, Kyoko; Nakagawa, Chinatsu; Soma, Masayoshi; Yoshida, Yukihiro; Ochiai, Toyoko; Tokuhashi, Yasuaki; Suzuki-Karasaki, Yoshihiro

    2014-11-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer treatment, but some cancer cell types are resistant to TRAIL cytotoxicity. Therefore, overcoming this resistance is necessary for effective TRAIL therapy. Mitochondrial morphology is important for the maintenance of cell function and survival, and is regulated by the delicate balance between fission and fusion. However, the role of mitochondrial morphology dynamics in TRAIL-induced apoptosis is unknown. Here we show that mitochondrial division inhibitor-1 (mdivi-1), an inhibitor of dynamin-related protein1 (Drp1), modulates mitochondrial morphology and TRAIL-induced apoptosis in human cancer cells. mdivi-1 treatment (?12.5 M) caused dose- and time?dependent cell death in malignant melanoma, lung cancer and osteosarcoma cells, while sparing normal cells. mdivi-1 also sensitized cancer cells to TRAIL-induced apoptosis. This potentiation of apoptosis occurred through a caspase-depependent mechanism including the mitochondrial and endoplasmic reticulum (ER) stress pathways. Mdivi-1 potentiated mitochondrial oxidative stress, a major cause of mitochondrial and ER stresses, as evidenced by increases in mitochondrial reactive oxygen species levels, mitochondrial mass, and cardiolipin oxidation. Live cell fluorescence imaging using MitoTracker Red CMXRos revealed that Mdivi-1 caused substantial mitochondrial hyperfusion. Moreover, silencing of Drp1 expression also caused mitochondrial hyperfusion and sensitized cancer cells to TRAIL-induced apoptosis. Our results suggest that cancer cells are more vulnerable than normal cells to a perturbation in mitochondrial morphology dynamics and that this higher susceptibility can be exploited to selectively kill cancer cells and sensitize to TRAIL. PMID:25174275

  10. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334) ameliorates murine colitis

    PubMed Central

    Gupta, Ram; Chaudhary, Anita R; Shah, Binita N; Jadhav, Avinash V; Zambad, Shitalkumar P; Gupta, Ramesh Chandra; Deshpande, Shailesh; Chauthaiwale, Vijay; Dutt, Chaitanya

    2014-01-01

    Background and aim Mucosal healing in inflammatory bowel disease (IBD) can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF) has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohns disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor ameliorates IBD in disease models. These findings highlight the potential of TRC160334 for its clinical application in the treatment of IBD. PMID:24493931

  11. The farnesyltransferase inhibitor, FPT inhibitor III upregulates Bax and Bcl-xs expression and induces apoptosis in human ovarian cancer cells.

    PubMed

    Hung, W C; Chaung, L Y

    1998-01-01

    Deregulation in the ras oncogene is a common event in many types of human cancer. Our previous study clearly demonstrated that genetic alterations of ras oncogene are frequently found in human epithelial ovarian cancer. Recent reports have indicated that farnesyltransferase is involved in the regulation of post-translational modification and biological function of Ras proteins. Here, we report that a newly synthesized farnesyltransferase inhibitor, FPT inhibitor III, upregulates Bax and Bcl-xs expression and induces apoptosis in human ovarian cancer cells. This is a critical finding that farnesyltransferase inhibitors may directly activate apoptotic signaling pathways in cancer cells and may help to provide a new strategy in the treatment of human cancer. PMID:9454897

  12. SELECTIVE AND NON-SELECTIVE METALLOPROTEINASE INHIBITORS REDUCE IL-1-INDUCED CARTILAGE DEGRADATION AND LOSS OF MECHANICAL PROPERTIES

    PubMed Central

    Wilson, Christopher G.; Palmer, Ashley W.; Zuo, Fengrong; Eugui, Elsie; Wilson, Stacy; Mackenzie, Rebecca; Sandy, John D.; Levenston, Marc E.

    2015-01-01

    Articular cartilage undergoes matrix degradation and loss of mechanical properties when stimulated with proinflammatory cytokines such as interleukin-1 (IL-1). Aggrecanases and matrix metalloproteinases (MMPs) are thought to be principal downstream effectors of cytokine-induced matrix catabolism, and aggrecanase- or MMP-selective inhibitors reduce or block matrix destruction in several model systems. The objective of this study was to use metalloproteinase inhibitors to perturb IL-1-induced matrix catabolism in bovine cartilage explants and examine their effects on changes in tissue compression and shear properties. Explanted tissue was stimulated with IL-1 for up to 24 days in the absence or presence of inhibitors which were aggrecanase-selective, MMP-selective, or non-selective. Analysis of conditioned media and explant digests revealed that aggrecanase-mediated aggrecanolysis was delayed to varying extents with all inhibitor treatments, but that aggrecan release persisted. Collagen degradation was abrogated by MMP- and non-selective inhibitors and reduced by the aggrecanase inhibitor. The inhibitors delayed but did not reduce loss of the equilibrium compression modulus, whereas the loss of dynamic compression and shear moduli was delayed and reduced. The data suggest that non-metalloproteinase mechanisms participate in IL-1-induced matrix degradation and loss of tissue material properties. PMID:17174540

  13. Anmindenols A and B, inducible nitric oxide synthase inhibitors from a marine-derived Streptomyces sp.

    PubMed

    Lee, Jihye; Kim, Hiyoung; Lee, Tae Gu; Yang, Inho; Won, Dong Hwan; Choi, Hyukjae; Nam, Sang-Jip; Kang, Heonjoong

    2014-06-27

    Anmindenols A (1) and B (2), inhibitors of inducible nitric oxide synthase (iNOS), were isolated from a marine-derived bacterium Streptomyces sp. Their chemical structures were elucidated by interpreting various spectroscopic data, including IR, MS, and NMR. Anmindenols A and B are sesquiterpenoids possessing an indene moiety with five- and six-membered rings derived from isoprenyl units. The absolute configuration of C-4 in anmindenol B was determined by electronic circular dichroism (ECD) of a dimolybdenum complex. Anmindenols A (1) and B (2) inhibited nitric oxide production in stimulated RAW 264.7 macrophage cells with IC50 values of 23 and 19 μM, respectively. PMID:24878306

  14. Inhibitors of fatty acid amide hydrolase reduce carrageenan-induced hind paw inflammation in pentobarbital-treated mice: comparison with indomethacin and possible involvement of cannabinoid receptors

    PubMed Central

    Holt, Sandra; Comelli, Francesca; Costa, Barbara; Fowler, Christopher J

    2005-01-01

    The in vivo effect of inhibitors of fatty acid amide hydrolase (FAAH) upon oedema volume and FAAH activity was evaluated in the carrageenan induced hind paw inflammation model in the mouse. Oedema was measured at two time points, 2 and 4 h, after intraplantar injection of carrageenan to anaesthetised mice. Intraperitoneal (i.p.) injections of the FAAH inhibitor URB597 (0.1, 0.3, 1 and 3 mg kg−1) 30 min prior to carrageenan administration, dose-dependently reduced oedema formation. At the 4 h time point, the ED50 for URB597 was ∼0.3 mg kg−1. Indomethacin (5 mg kg−1 i.p.) completely prevented the oedema response to carrageenan. The antioedema effects of indomethacin and URB597 were blocked by 3 mg kg−1 i.p. of the CB2 receptor antagonist SR144528. The effect of URB597 was not affected by pretreatment with the peroxisome proliferator-activated receptor γ antagonist bisphenol A diglycidyl ether (30 mg kg−1 i.p.) or the TRPV1 antagonist capsazepine (10 mg kg−1 i.p.), when oedema was assessed 4 h after carrageenan administration. The CB1 receptor antagonists AM251 (3 mg kg−1 i.p.) and rimonabant (0.5 mg kg−1 i.p.) gave inconsistent effects upon the antioedema effect of URB597. FAAH measurements were conducted ex vivo in the paws, spinal cords and brains of the mice. The activities of FAAH in the paws and spinal cords of the inflamed vehicle-treated mice were significantly lower than the corresponding activities in the noninflamed mice. PMSF treatment almost completely inhibited the FAAH activity in all three tissues, as did the highest dose of URB597 (3 mg kg−1) in spinal cord samples, whereas no obvious changes were seen ex vivo for the other treatments. In conclusion, the results show that in mice, treatment with indomethacin and URB597 produce SR144528-sensitive anti-inflammatory effects in the carrageenan model of acute inflammation. PMID:16100529

  15. Heat shock protein inhibitors, 17-DMAG and KNK437, enhance arsenic trioxide-induced mitotic apoptosis

    SciTech Connect

    Wu Yichen; Yen Wenyen; Lee, T.-C. Yih, L.-H.

    2009-04-15

    Arsenic trioxide (ATO) has recently emerged as a promising therapeutic agent in leukemia because of its ability to induce apoptosis. However, there is no sufficient evidence to support its therapeutic use for other types of cancers. In this study, we investigated if, and how, 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17-DMAG), an antagonist of heat shock protein 90 (HSP90), and KNK437, a HSP synthesis inhibitor, potentiated the cytotoxic effect of ATO. Our results showed that cotreatment with ATO and either 17-DMAG or KNK437 significantly increased ATO-induced cell death and apoptosis. siRNA-mediated attenuation of the expression of the inducible isoform of HSP70 (HSP70i) or HSP90{alpha}/{beta} also enhanced ATO-induced apoptosis. In addition, cotreatment with ATO and 17-DMAG or KNK437 significantly increased ATO-induced mitotic arrest and ATO-induced BUBR1 phosphorylation and PDS1 accumulation. Cotreatment also significantly increased the percentage of mitotic cells with abnormal mitotic spindles and promoted metaphase arrest as compared to ATO treatment alone. These results indicated that 17-DMAG or KNK437 may enhance ATO cytotoxicity by potentiating mitotic arrest and mitotic apoptosis possibly through increased activation of the spindle checkpoint.

  16. Nuclear Factor Kappa B Activation and Peroxisome Proliferator-activated Receptor Transactivational Effects of Chemical Components of the Roots of Polygonum multiflorum

    PubMed Central

    Sun, Ya Nan; Li, Wei; Song, Seok Bean; Yan, Xi Tao; Yang, Seo Young; Kim, Young Ho

    2016-01-01

    Background: Polygonum multiflorum is well-known as “Heshouwu” in traditional Chinese herbal medicine. In Northeast Asia, it is often used as a tonic to prevent premature aging of the kidney and liver, tendons, and bones and strengthening of the lower back and knees. Objective: To research the anti-inflammatory activities of components from P. multiflorum. Materials and Methods: The compounds were isolated by a combination of silica gel and YMC R-18 column chromatography, and their structures were identified by analysis of spectroscopic data (1D, 2D-nuclear magnetic resonance, and mass spectrometry). The anti-inflammatory activities of the isolated compounds 1−15 were evaluated by luciferase reporter gene assays. Results: Fifteen compounds (1–15) were isolated from the roots of P. multiflorum. Compounds 1−5 and 14−15 significantly inhibited tumor necrosis factor-α-induced nuclear factor kappa B-luciferase activity, with IC50 values of 24.16-37.56 μM. Compounds 1−5 also greatly enhanced peroxisome proliferator-activated receptors transcriptional activity with EC50 values of 18.26−31.45 μM. Conclusion: The anthraquinone derivatives were the active components from the roots of P. multiflorum as an inhibitor on inflammation-related factors in human hepatoma cells. Therefore, we suggest that the roots of P. multiflorum can be used to treat natural inflammatory diseases. SUMMARY This study presented that fifteen compounds (1-15) isolated from the roots of Polygonum multiflrum exert signifiant anti inflmmatory effects by inhibiting TNF α induced NF κB activation and PPARs transcription. Abbreviation used: NF κB: Nuclear factor kappa B, PPARs: Peroxisome proliferator activated receptors, PPREs: Peroxisome proliferator response elements, TNF α: Tumor necrosis factor α, ESI-MS: Electrospray ionization mass spectrometry, HepG2: Human hepatoma cells

  17. Identification of an Allosteric Small Molecule Inhibitor Selective for Inducible Form of Heat Shock Protein 70

    PubMed Central

    Howe, Matthew K.; Bodoor, Khaldon; Carlson, David A.; Hughes, Philip F.; Alwarawrah, Yazan; Loiselle, David R.; Jaeger, Alex M.; Darr, David B.; Jordan, Jamie L.; Hunter, Lucas M.; Molzberger, Eileen T.; Gobillot, Theodore A.; Thiele, Dennis J.; Brodsky, Jeffrey L.; Spector, Neil L.; Haystead, Timothy A. J.

    2014-01-01

    Summary Inducible Hsp70 (Hsp70i) is overexpressed in a wide spectrum of human tumors and its expression correlates with metastasis, poor outcomes, and resistance to chemotherapy in patients. Identification of small molecule inhibitors selective for Hsp70i could provide new therapeutic tools for cancer treatment. In this work, we used fluorescence-linked enzyme chemoproteomic strategy (FLECS) to identify HS-72, an allosteric inhibitor selective for Hsp70i. HS-72 displays the hallmarks of Hsp70 inhibition in cells, promoting substrate protein degradation and growth inhibition. Importantly, HS-72 is selective for Hsp70i over the closely related constitutively active Hsc70. Studies with purified protein show HS-72 acts as an allosteric inhibitor, reducing ATP affinity. In vivo HS-72 is well-tolerated, showing bioavailability and efficacy, inhibiting tumor growth and promoting survival in a HER2+ model of breast cancer. The HS-72 scaffold is amenable to resynthesis and iteration, suggesting an ideal starting point for a new generation of anticancer therapeutics targeting Hsp70i. PMID:25500222

  18. Binding-induced, turn-on fluorescence of the EGFR/ERBB kinase inhibitor, lapatinib.

    PubMed

    Wilson, James N; Liu, Wenjun; Brown, Adrienne S; Landgraf, Ralf

    2015-05-01

    We report the photophysical properties, binding-induced turn-on emission, and fluorescence imaging of the cellular uptake and distribution of lapatinib, an EGFR/ERBB inhibitor. Lapatinib, a type II, i.e. inactive state, inhibitor that targets the ATP binding pocket of the EGFR family of receptor tyrosine kinases. DFT calculations predict that the 6-furanylquinazoline core of lapatinib should exhibit an excited state with charge transfer character and an S0 to S1 transition energy of 3.4 eV. Absorption confirms an optical transition in the near UV to violet, while fluorescence spectroscopy shows that photoemission is highly sensitive to solvent polarity. The hydrophobicity of lapatinib leads to fluorescent aggregates in solution, however, binding to the lipid-carrier protein, BSA or to the kinase domain of ERBB2, produces spectroscopically distinct photoemission. Confocal fluorescence microscopy imaging of lapatinib uptake in ERBB2-overexpressing MCF7 and BT474 cells reveals pools of intracellular inhibitor with emission profiles consistent with aggregated lapatinib. PMID:25820099

  19. mTOR inhibitors counteract tamoxifen-induced activation of breast cancer stem cells.

    PubMed

    Karthik, Govindasamy-Muralidharan; Ma, Ran; Lvrot, John; Kis, Lorand Levente; Lindh, Claes; Blomquist, Lennart; Fredriksson, Irma; Bergh, Jonas; Hartman, Johan

    2015-10-10

    Breast cancer cells with stem cell characteristics (CSC) are a distinct cell population with phenotypic similarities to mammary stem cells. CSCs are important drivers of tumorigenesis and the metastatic process. Tamoxifen is the most widely used hormonal therapy for estrogen receptor (ER) positive cancers. In our study, tamoxifen was effective in reducing proliferation of ER?+?adherent cancer cells, but not their CSC population. We isolated, expanded and incubated CSC from seven breast cancers with or without tamoxifen. By genome-wide transcriptional analysis we identified tamoxifen-induced transcriptional pathways associated with ribosomal biogenesis and mRNA translation, both regulated by the mTOR-pathway. We observed induction of the key mTOR downstream targets S6K1, S6RP and 4E-BP1 in-patient derived CSCs by tamoxifen on protein level. Using the mTOR inhibitors rapamycin, everolimus and PF-04691502 (a dual PI3K/mTOR inhibitor) and in combination with tamoxifen, significant reduction in mammosphere formation was observed. Hence, we suggest that the CSC population play a significant role during endocrine resistance through activity of the mTOR pathway. In addition, tamoxifen further stimulates the mTOR-pathway but can be antagonized using mTOR-inhibitors. PMID:26208432

  20. Betulin, betulinic acid and butein are inhibitors of acetaldehyde-induced activation of liver stellate cells.

    PubMed

    Szuster-Ciesielska, Agnieszka; Plewka, Krzysztof; Kandefer-Szerszeń, Martyna

    2011-01-01

    Liver fibrosis has been reported to be inhibited in vivo by oleanolic and ursolic acids; however, the activity of other triterpenes like betulin and betulinic acid has not been examined. Butein has also been reported to prevent and partly reverse liver fibrosis in vivo, although its mechanism of action is poorly understood. Therefore, the aim of this study was to determine the antifibrotic potential of butein, betulin, and betulinic acid and examine their mechanisms of action in vitro. This study was conducted in rat stellate cells (HSCs) that were treated with acetaldehyde, which is the most reactive product of ethanol metabolism. Butein, betulin, and betulinic acid were preincubated with rat HSCs at non-toxic concentrations. Treatment effects were measured in regard to acetaldehyde-induced toxicity and cell migration, and several markers of HSC activation were evaluated, including smooth muscle α-actin (α-SMA) and procollagen I expression. In addition, changes in the release of reactive oxygen species (ROS) and cytokines such as tumor necrosis factor-α (TNF-α) and tumor growth factor-β1 (TGF-β1) and changes in the production of metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) were determined. In vitro, HSCs were protected against acetaldehyde-induced toxicity by betulin but not by betulinic acid and butein. However, butein, betulin, and betulinic acid inhibited the production of ROS by HSCs treated with acetaldehyde and inhibited their migration. Butein also inhibited acetaldehyde-induced TGF-β1 production. Butein, betulin, and betulinic acid down-regulated acetaldehyde-induced production of TIMP-1 and TIMP-2. Betulin decreased the acetaldehyde-induced activity of MMP-2, but butein and betulinic acid did not. The results indicated that butein, betulin, and betulinic acid inhibited the acetaldehyde-induced activation of HSCs. Each drug functioned in a different manner, whereby some were acting as either antioxidants or inhibitors of TIMPs expression and butein additionally acted as an inhibitor of TGF-β production. PMID:22180353

  1. Topically applied Hsp90 inhibitor 17AAG inhibits UVR-induced cutaneous squamous cell carcinomas.

    PubMed

    Singh, Anupama; Singh, Ashok; Sand, Jordan M; Bauer, Samuel J; Hafeez, Bilal Bin; Meske, Louise; Verma, Ajit K

    2015-04-01

    We present here that heat-shock protein 90 (Hsp90) inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17AAG), when topically applied to mouse skin, inhibits UVR-induced development of cutaneous squamous cell carcinoma (SCC). In these experiments, DMSO:acetone (1:40 v/v) solution of 17AAG (500?nmol) was applied topically to mouse skin in conjunction with each UVR exposure (1.8?kJ?m(-2)). The UVR source was Kodacel-filtered FS-40 sun lamps (approximately 60% UVB and 40% UVA). In independent experiments with three separate mouse lines (SKH-1 hairless mice, wild-type FVB, and protein kinase C epsilon (PKC?)-overexpressing transgenic FVB mice), 17AAG treatment increased the latency and decreased both the incidence and multiplicity of UVR-induced SCC. Topical 17AAG alone or in conjunction with UVR treatments elicited neither skin nor systemic toxicity. 17AAG-caused inhibition of SCC induction was accompanied by a decrease in UVR-induced (1) hyperplasia, (2) Hsp90?-PKC? interaction, and (3) expression levels of Hsp90?, Stat3, pStat3Ser727, pStat3Tyr705, pAktSer473, and matrix metalloproteinase (MMP). The results presented here indicate that topical Hsp90 inhibitor 17AAG is effective in prevention of UVR-induced epidermal hyperplasia and SCC. One may conclude from the preclinical data presented here that topical 17AAG may be useful for prevention of UVR-induced inflammation and cutaneous SCC either developed in UVR-exposed or organ transplant population. PMID:25337691

  2. Cytoprotective effect of selective small-molecule caspase inhibitors against staurosporine-induced apoptosis

    PubMed Central

    Wu, Jianghong; Wang, Yuren; Liang, Shuguang; Ma, Haiching

    2014-01-01

    Caspases are currently known as the central executioners of the apoptotic pathways. Inhibition of apoptosis and promotion of normal cell survival by caspase inhibitors would be a tremendous benefit for reducing the side effects of cancer therapy and for control of neurodegenerative disorders such as Parkinsons, Alzheimers, and Huntingtons diseases. The objective of this study was to discover small-molecule caspase inhibitors with which to achieve cytoprotective effect. We completed the high-throughput screening of Bionets 37,500-compound library (Key Organics Limited, Camelford, Cornwall, UK) against caspase-1, -3, and -9 and successfully identified 43 initial hit compounds. The 43 hit compounds were further tested for cytoprotective activity against staurosporine-induced cell death in NIH3T3 cells. Nineteen compounds were found to have significant cytoprotective effects in cell viability assays. One of the compounds, RBC1023, was demonstrated to protect NIH3T3 cells from staurosporine-induced caspase-3 cleavage and activation. RBC1023 was also shown to protect against staurosporine-induced impairment of mitochondrial membrane potential. DNA microarray analysis demonstrated that staurosporine treatment induced broad global gene expression alterations, and RBC1023 co-treatment significantly restored these changes, especially of the genes that are related to cell growth and survival signaling such as Egr1, Cdc25c, cdkn3, Rhob, Nek2, and Taok1. Collectively, RBC1023 protects NIH3T3 cells against staurosporine-induced apoptosis via inhibiting caspase activity, restoring mitochondrial membrane potential, and possibly upregulating some cell survival-related gene expressions and pathways. PMID:24920883

  3. Use of a soluble epoxide hydrolase inhibitor in smoke-induced chronic obstructive pulmonary disease.

    PubMed

    Wang, Lei; Yang, Jun; Guo, Lei; Uyeminami, Dale; Dong, Hua; Hammock, Bruce D; Pinkerton, Kent E

    2012-05-01

    Tobacco smoke-induced chronic obstructive pulmonary disease (COPD) is a prolonged inflammatory condition of the lungs characterized by progressive and largely irreversible airflow limitation attributable to a number of pathologic mechanisms, including bronchitis, bronchiolitis, emphysema, mucus plugging, pulmonary hypertension, and small-airway obstruction. Soluble epoxide hydrolase inhibitors (sEHIs) demonstrated anti-inflammatory properties in a rat model after acute exposure to tobacco smoke. We compared the efficacy of sEHI t-TUCB (trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid) and the phosphodiesterase-4 (PDE4) inhibitor Rolipram (Biomol International, Enzo Life Sciences, Farmingdale, NY) to reduce lung injury and inflammation after subacute exposure to tobacco smoke over a period of 4 weeks. Pulmonary physiology, bronchoalveolar lavage, cytokine production, and histopathology were analyzed to determine the efficacy of sEHI and Rolipram to ameliorate tobacco smoke-induced inflammation and injury in the spontaneously hypertensive rat. Both t-TUCB and Rolipram inhibited neutrophil elevation in bronchoalveolar lavage. sEHI t-TUCB suppressed IFN-?, while improving lung function by reducing tobacco smoke-induced total respiratory resistance and tissue damping (small-airway and peripheral tissue resistance). Increases in tobacco smoke-induced alveolar airspace size were attenuated by t-TUCB. Rolipram inhibited the production of airway mucus. Both t-TUCB and Rolipram inhibited vascular remodeling-related growth factor. These findings suggest that sEHI t-TUCB has therapeutic potential for treating COPD by improving lung function and attenuating the lung inflammation and emphysematous changes caused by tobacco smoke. To the best of our knowledge, this is the first report to demonstrate that sEHI exerts significant protective effects after repeated, subacute tobacco smoke-induced lung injury in a rat model of COPD. PMID:22180869

  4. Topically applied Hsp90 inhibitor 17AAG inhibits ultraviolet radiation-induced cutaneous squamous cell carcinomas

    PubMed Central

    Singh, Anupama; Singh, Ashok; Sand, Jordan M.; Bauer, Samuel J.; Hafeez, Bilal Bin; Meske, Louise; Verma, Ajit K.

    2014-01-01

    We present here that Heat shock protein 90 (Hsp90) inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17AAG), when topically applied to mouse skin, inhibits ultraviolet radiation (UVR)-induced development of cutaneous squamous cell carcinoma (SCC). In these experiments, DMSO:acetone (1:40 v/v) solution of 17AAG (500nmol) was applied topically to mouse skin in conjunction with each UVR exposure (1.8 kJ/m2). The UVR source was Kodacel-filtered FS-40 sun lamps (approximately 60% UVB and 40% UVA). In independent experiments with three separate mouse lines (SKH-1 hairless mice, wild-type FVB, and PKCε overexpressing transgenic FVB mice), 17AAG treatment increased the latency and decreased both the incidence and multiplicity of UVR-induced SCC. Topical 17AAG alone or in conjunction with UVR treatments elicited neither skin nor systemic toxicity. 17AAG-caused inhibition of SCC induction was accompanied by decrease in UVR-induced: 1) hyperplasia, 2) Hsp90β-PKCε interaction, 3) expression levels of Hsp90β, Stat3, pStat3Ser727, pStat3Tyr705, pAktSer473 and matrix metalloproteinase (MMPs). The results presented here indicate that topical Hsp90 inhibitor 17AAG is effective in prevention of UVR-induced epidermal hyperplasia and SCC. One may conclude from the preclinical data presented here that topical 17AAG may be useful for prevention of UVR-induced inflammation and cutaneous SCC either developed in UVR exposed or organ transplant population. PMID:25337691

  5. Proteasome inhibitor MG-132 induces C6 glioma cell apoptosis via oxidative stress

    PubMed Central

    Fan, Wen-hai; Hou, Yi; Meng, Fan-kai; Wang, Xiao-fei; Luo, Yi-nan; Ge, Peng-fei

    2011-01-01

    Aim: Proteasome inhibitors have been found to suppress glioma cell proliferation and induce apoptosis, but the mechanisms are not fully elucidated. In this study we investigated the mechanisms underlying the apoptosis induced by the proteasome inhibitor MG-132 in glioma cells. Methods: C6 glioma cells were used. MTT assay was used to analyze cell proliferation. Proteasome activity was assayed using Succinyl-LLVY-AMC, and intracellular ROS level was evaluated with the redox-sensitive dye DCFH-DA. Apoptosis was detected using fluorescence and transmission electron microscopy as well as flow cytometry. The expression of apoptosis-related proteins was investigated using Western blot analysis. Results: MG-132 inhibited C6 glioma cell proliferation in a time- and dose-dependent manner (the IC50 value at 24 h was 18.5 ?mol/L). MG-132 (18.5 ?mol/L) suppressed the proteasome activity by about 70% at 3 h. It induced apoptosis via down-regulation of antiapoptotic proteins Bcl-2 and XIAP, up-regulation of pro-apoptotic protein Bax and caspase-3, and production of cleaved C-terminal 85 kDa PARP). It also caused a more than 5-fold increase of reactive oxygen species. Tiron (1 mmol/L) effectively blocked oxidative stress induced by MG-132 (18.5 ?mol/L), attenuated proliferation inhibition and apoptosis in C6 glioma cells, and reversed the expression pattern of apoptosis-related proteins. Conclusion: MG-132 induced apoptosis of C6 glioma cells via the oxidative stress. PMID:21499287

  6. Histone deacetylase inhibitor treatment induces 'BRCAness' and synergistic lethality with PARP inhibitor and cisplatin against human triple negative breast cancer cells.

    PubMed

    Ha, Kyungsoo; Fiskus, Warren; Choi, Dong Soon; Bhaskara, Srividya; Cerchietti, Leandro; Devaraj, Santhana G T; Shah, Bhavin; Sharma, Sunil; Chang, Jenny C; Melnick, Ari M; Hiebert, Scott; Bhalla, Kapil N

    2014-07-30

    There is an unmet need to develop new, more effective and safe therapies for the aggressive forms of triple negative breast cancers (TNBCs). While up to 20% of women under 50 years of age with TNBC harbor germline mutations in BRCA1, and these tumors are sensitive to treatment with poly(ADP) ribose polymerase inhibitors, a majority of TNBCs lack BRCA1 mutations or loss of expression. Findings presented here demonstrate that by attenuating the levels of DNA damage response and homologous recombination proteins, pan-histone deacetylase inhibitor (HDI) treatment induces 'BRCAness' and sensitizes TNBC cells lacking BRCA1 to lethal effects of PARP inhibitor or cisplatin. Treatment with HDI also induced hyperacetylation of nuclear hsp90. Similar effects were observed following shRNA-mediated depletion of HDAC3, confirming its role as the deacetylase for nuclear HSP90. Furthermore, cotreatment with HDI and ABT-888 induced significantly more DNA strand breaks than either agent alone, and synergistically induced apoptosis of TNBC cells. Notably, co-treatment with HDI and ABT-888 significantly reduced in vivo tumor growth and markedly improved the survival of mice bearing TNBC cell xenografts. These findings support the rationale to interrogate the clinical activity of this novel combination against human TNBC, irrespective of its expression of mutant BRCA1. PMID:25026298

  7. Histone deacetylase inhibitor treatment induces BRCAness and synergistic lethality with PARP inhibitor and cisplatin against human triple negative breast cancer cells

    PubMed Central

    Ha, Kyungsoo; Bhaskara, Srividya; Cerchietti, Leandro; Devaraj, Santhana G. T.; Shah, Bhavin; Sharma, Sunil; Chang, Jenny C.; Melnick, Ari M.; Hiebert, Scott; Bhalla, Kapil N.

    2014-01-01

    There is an unmet need to develop new, more effective and safe therapies for the aggressive forms of triple negative breast cancers (TNBCs). While up to 20% of women under 50 years of age with TNBC harbor germline mutations in BRCA1, and these tumors are sensitive to treatment with poly(ADP) ribose polymerase inhibitors, a majority of TNBCs lack BRCA1 mutations or loss of expression. Findings presented here demonstrate that by attenuating the levels of DNA damage response and homologous recombination proteins, pan-histone deacetylase inhibitor (HDI) treatment induces BRCAness and sensitizes TNBC cells lacking BRCA1 to lethal effects of PARP inhibitor or cisplatin. Treatment with HDI also induced hyperacetylation of nuclear hsp90. Similar effects were observed following shRNA-mediated depletion of HDAC3, confirming its role as the deacetylase for nuclear HSP90. Furthermore, cotreatment with HDI and ABT-888 induced significantly more DNA strand breaks than either agent alone, and synergistically induced apoptosis of TNBC cells. Notably, co-treatment with HDI and ABT-888 significantly reduced in vivo tumor growth and markedly improved the survival of mice bearing TNBC cell xenografts. These findings support the rationale to interrogate the clinical activity of this novel combination against human TNBC, irrespective of its expression of mutant BRCA1. PMID:25026298

  8. Eribulin synergizes with Polo-like kinase 1 inhibitors to induce apoptosis in rhabdomyosarcoma.

    PubMed

    Stehle, Angelika; Hugle, Manuela; Fulda, Simone

    2015-08-28

    Eribulin, a novel microtubule-interfering drug, was recently shown to exhibit high antitumor activity in vivo against various pediatric cancers. Here, we identify a novel synthetic lethal interaction of Eribulin together with Polo-like kinase 1 (PLK1) inhibitors against rhabdomyosarcoma (RMS) in vitro and in vivo. Eribulin and the PLK1 inhibitor BI2536 at subtoxic concentrations synergize to induce apoptosis in RMS cells as confirmed by calculation of combination index (CI). Also, Eribulin/BI2536 co-treatment is significantly more effective than monotherapy to reduce cell viability and inhibit colony formation of RMS cells. Similarly, Eribulin and BI2536 act in concert to trigger apoptosis in a primary, patient-derived ARMS culture, underscoring the clinical relevance of this combination. Importantly, Eribulin and BI 2536 cooperate to suppress tumor growth in an in vivo model of RMS. On molecular grounds, Eribulin/BI2536 co-treatment causes profound mitotic arrest, which is critically required for synergism, since inhibition of mitotic arrest by CDK1 inhibitor RO-3306 abolishes Eribulin/BI2536-mediated apoptosis. Eribulin and BI 2536 cooperate to activate caspase-9, -3 and -8, which is necessary for apoptosis induction, since the broad-range caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) reduces Eribulin/BI2536-induced apoptosis significantly, yet partially. Intriguingly, knockdown of endonuclease G (ENDOG) also significantly inhibits Eribulin/BI2536-triggered apoptosis, demonstrating the involvement of both caspase-dependent and -independent effector pathways. Synergistic induction of apoptosis is similarly found for Eribulin/BI 2536 co-treatment in neuroblastoma cells and for the combination of vincristine (another antimicrotubule chemotherapeutic) with Poloxin (another PLK1 inhibitor), thus pointing to a broader significance of this concomitant microtubule- and PLK1-targeting strategy for pediatric oncology. In conclusion, the identification of a novel synthetic lethality by dual targeting of mitosis using microtubule-interfering and PLK1-targeted drugs, i.e. Eribulin and BI 2536, has important implications for the development of more effective treatment strategies for RMS. PMID:25917079

  9. Topoisomerase II inhibitors induce DNA double-strand breaks at a specific site within the AML1 locus.

    PubMed

    Stanulla, M; Wang, J; Chervinsky, D S; Aplan, P D

    1997-04-01

    Treatment-related acute myeloid leukemia (t-AML) following successful therapy of a primary malignancy has been recognized with increasing frequency among cancer survivors over the past several years. Many of these t-AML cases are associated with the use of intensive chemotherapy regimens that employ one or more agents which target eukaryotic topoisomerase II (topo II), and demonstrate non-random chromosomal translocations involving either the MLL (ALL-1, HRX) gene at 11q23 or the AML1 gene at 21q22. Although many investigators have speculated that these translocations are induced by the therapeutic use of topo II inhibitors, the molecular sequence of events by which topo II inhibitors might induce a chromosomal translocation are not well understood. We describe here the reproducible induction of highly specific, double-strand DNA cleavage at a specific site within the AML1 locus by topo II inhibitors. This DNA cleavage, which maps to a region of the AML1 locus frequently disrupted by chromosomal translocations, can be induced in several cell lines, with multiple different topo II inhibitors, indicating that this phenomenon is not restricted to a specific cell type or specific topo II inhibitor. It is conceivable that site-specific double-strand DNA cleavage within the AML1 locus induced by topo II inhibitors represents the initial molecular event leading to a chromosomal translocation and t-AML. PMID:9096688

  10. Phenylbutyrate up-regulates the adrenoleukodystrophy-related gene as a nonclassical peroxisome proliferator

    PubMed Central

    Gondcaille, Catherine; Depreter, Marianne; Fourcade, Stphane; Lecca, Maria Rita; Leclercq, Sabrina; Martin, Pascal G.P.; Pineau, Thierry; Cadepond, Franoise; ElEtr, Martine; Bertrand, Nathalie; Beley, Alain; Duclos, Sandrine; De Craemer, Dirk; Roels, Frank; Savary, Stphane; Bugaut, Maurice

    2005-01-01

    X-linked adrenoleukodystrophy (X-ALD) is a demyelinating disease due to mutations in the ABCD1 (ALD) gene, encoding a peroxisomal ATP-binding cassette transporter (ALDP). Overexpression of adrenoleukodystrophy-related protein, an ALDP homologue encoded by the ABCD2 (adrenoleukodystrophy-related) gene, can compensate for ALDP deficiency. 4-Phenylbutyrate (PBA) has been shown to induce both ABCD2 expression and peroxisome proliferation in human fibroblasts. We show that peroxisome proliferation with unusual shapes and clusters occurred in liver of PBA-treated rodents in a PPAR?-independent way. PBA activated Abcd2 in cultured glial cells, making PBA a candidate drug for therapy of X-ALD. The Abcd2 induction observed was partially PPAR? independent in hepatocytes and totally independent in fibroblasts. We demonstrate that a GC box and a CCAAT box of the Abcd2 promoter are the key elements of the PBA-dependent Abcd2 induction, histone deacetylase (HDAC)1 being recruited by the GC box. Thus, PBA is a nonclassical peroxisome proliferator inducing pleiotropic effects, including effects at the peroxisomal level mainly through HDAC inhibition. PMID:15809314

  11. The PI3K inhibitor GS-1101 synergistically potentiates HDAC inhibitor-induced proliferation inhibition and apoptosis through the inactivation of PI3K and ERK pathways

    PubMed Central

    Bodo, Juraj; Zhao, Xiaoxian; Sharma, Arishya; Hill, Brian T.; Portell, Craig A.; Lannutti, Brian J.; Almasan, Alexandru; Hsi, Eric D.

    2013-01-01

    Previously, we showed that inhibition of the protein kinase C ? (PKC?)/AKT pathway augments engagement of the histone deacetylase inhibitor (HDI)-induced apoptosis in lymphoma cells. In the present study, we investigated the cytotoxicity and mechanisms of cell death induced by the delta isoform-specific phosphatidylinositide 3-kinase (PI3K) inhibitor, GS-1101, in combination with the HDI, panobinostat (LBH589) and suberoylanilide hydroxamic acid (SAHA). Lymphoma cell lines and primary Non-Hodgkin Lymphoma (NHL) and chronic lymphocytic leukaemia (CLL) cells were simultaneously treated with the HDI, LBH589 and GS-1101. An interaction of the LBH589/GS-1101 combination was formally examined by using various concentrations of LBH589 and GS-1101. Combined treatment resulted in a synergistic inhibition of proliferation and showed synergistic effect on apoptotic induction in all tested cell lines and primary NHL and CLL cells. This study indicates that interference with PI3K signalling dramatically increases HDI-mediated apoptosis in malignant haematopoietic cells, possibly through both AKT-dependent or AKT- independent mechanisms. Moreover, the increase in HDI-related apoptosis observed in PI3K inhibitor-treated cells appears to be related to the disruption of the extracellular signal-regulated kinase (ERK) signalling pathway. This study provides a strong rational for testing the combination of PI3K inhibitors and HDI in the clinic. PMID:23889282

  12. Changes in membrane surface properties of hepatic peroxisomes of rats under several conditions as determined by partition in aqueous polymer two-phase systems.

    PubMed

    Horie, S; Ishii, H; Orii, H; Suga, T

    1982-08-25

    Changes in membrane surface properties of hepatic peroxisomes of rats under several conditions were observed by aqueous polymer two-phase systems, which contained 6% (w/w) dextran T 500, 6% (w/w) polyethyleneglycol 4000, 250 mmol sucrose/kg and various concentrations of sodium phosphate buffer. The partition of peroxisomes into the upper phase depended to a large extent on their membrane surface charge. The cross-points of peroxisomes shifted from 5.55 to 5.25 and 5.2 after the administration of clofibrate and aspirin for 2 weeks, respectively, although that of alloxan-diabetic rat peroxisomes was not altered. The hydrophobic properties of peroxisomes, examined by means of a partition containing polyethyleneglycol monostearate, were altered by diabetes and starvation, but no change occurred in rats treated with clofibrate or aspirin. In the liver of rats fed a high-fat diet, the partition of peroxisomes was the same as that of the control. These findings indicate that hypolipidemic drugs such as clofibrate and aspirin induce the proliferation of peroxisomes and lead to the alteration of the surface charge of peroxisomal membranes. Diabetes or fasting lead to an alteration mainly of the hydrophobic properties. Both changes are probably due to alteration of content and/or composition of the proteins and the phospholipids in peroxisomal membrane under the conditions used. PMID:7126569

  13. Reduced peroxisomal citrate synthase activity increases substrate availability for polyhydroxyalkanoate biosynthesis in plant peroxisomes.

    PubMed

    Tilbrook, Kimberley; Poirier, Yves; Gebbie, Leigh; Schenk, Peer M; McQualter, Richard B; Brumbley, Stevens M

    2014-10-01

    Polyhydroxyalkanoates (PHAs) are bacterial carbon storage polymers used as renewable, biodegradable plastics. PHA production in plants may be a way to reduce industrial PHA production costs. We recently demonstrated a promising level of peroxisomal PHA production in the high biomass crop species sugarcane. However, further production strategies are needed to boost PHA accumulation closer to commercial targets. Through exogenous fatty acid feeding of Arabidopsis thaliana plants that contain peroxisome-targeted PhaA, PhaB and PhaC enzymes from Cupriavidus necator, we show here that the availability of substrates derived from the β-oxidation cycle limits peroxisomal polyhydroxybutyrate (PHB) biosynthesis. Knockdown of peroxisomal citrate synthase activity using artificial microRNA increased PHB production levels approximately threefold. This work demonstrates that reduction of peroxisomal citrate synthase activity may be a valid metabolic engineering strategy for increasing PHA production in other plant species. PMID:24944109

  14. Pharmacologic Profiling of Phosphoinositide 3-Kinase Inhibitors as Mitigators of Ionizing RadiationInduced Cell Death

    PubMed Central

    Sharlow, Elizabeth R.; Epperly, Michael W.; Lira, Ana; Leimgruber, Stephanie; Skoda, Erin M.; Wipf, Peter; Greenberger, Joel S.

    2013-01-01

    Ionizing radiation (IR) induces genotoxic stress that triggers adaptive cellular responses, such as activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling cascade. Pluripotent cells are the most important population affected by IR because they are required for cellular replenishment. Despite the clear danger to large population centers, we still lack safe and effective therapies to abrogate the life-threatening effects of any accidental or intentional IR exposure. Therefore, we computationally analyzed the chemical structural similarity of previously published small molecules that, when given after IR, mitigate cell death and found a chemical cluster that was populated with PI3K inhibitors. Subsequently, we evaluated structurally diverse PI3K inhibitors. It is remarkable that 9 of 14 PI3K inhibitors mitigated ?IR-induced death in pluripotent NCCIT cells as measured by caspase 3/7 activation. A single intraperitoneal dose of LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one], administered to mice at 4 or 24 hours, or PX-867 [(4S,4aR,5R,6aS,9aR,Z)-11-hydroxy-4-(methoxymethyl)-4a,6a-dimethyl-2,7,10-trioxo-1-(pyrrolidin-1-ylmethylene)-1,2,4,4a,5,6,6a,7,8,9,9a,10-dodecahydroindeno[4,5-H]isochromen-5-yl acetate (CID24798773)], administered 4 hours after a lethal dose of ?IR, statistically significantly (P < 0.02) enhanced in vivo survival. Because cell cycle checkpoints are important regulators of cell survival after IR, we examined cell cycle distribution in NCCIT cells after ?IR and PI3K inhibitor treatment. LY294002 and PX-867 treatment of nonirradiated cells produced a marked decrease in S phase cells with a concomitant increase in the G1 population. In irradiated cells, LY294002 and PX-867 treatment also decreased S phase and increased the G1 and G2 populations. Treatment with LY294002 or PX-867 decreased ?IR-induced DNA damage as measured by ?H2AX, suggesting reduced DNA damage. These results indicate pharmacologic inhibition of PI3K after IR abrogated cell death. PMID:24068833

  15. Redox interplay between mitochondria and peroxisomes

    PubMed Central

    Lismont, Celien; Nordgren, Marcus; Van Veldhoven, Paul P.; Fransen, Marc

    2015-01-01

    Reduction-oxidation or “redox” reactions are an integral part of a broad range of cellular processes such as gene expression, energy metabolism, protein import and folding, and autophagy. As many of these processes are intimately linked with cell fate decisions, transient or chronic changes in cellular redox equilibrium are likely to contribute to the initiation and progression of a plethora of human diseases. Since a long time, it is known that mitochondria are major players in redox regulation and signaling. More recently, it has become clear that also peroxisomes have the capacity to impact redox-linked physiological processes. To serve this function, peroxisomes cooperate with other organelles, including mitochondria. This review provides a comprehensive picture of what is currently known about the redox interplay between mitochondria and peroxisomes in mammals. We first outline the pro- and antioxidant systems of both organelles and how they may function as redox signaling nodes. Next, we critically review and discuss emerging evidence that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. Key issues include possible physiological roles, messengers, and mechanisms. We also provide examples of how data mining of publicly-available datasets from “omics” technologies can be a powerful means to gain additional insights into potential redox signaling pathways between peroxisomes and mitochondria. Finally, we highlight the need for more studies that seek to clarify the mechanisms of how mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress. The outcome of such studies may open up exciting new avenues for the community of researchers working on cellular responses to organelle-derived oxidative stress, a research field in which the role of peroxisomes is currently highly underestimated and an issue of discussion. PMID:26075204

  16. Tolerogenic nanoparticles to induce immunologic tolerance: Prevention and reversal of FVIII inhibitor formation.

    PubMed

    Zhang, Ai-Hong; Rossi, Robert J; Yoon, Jeongheon; Wang, Hong; Scott, David W

    2016-03-01

    The immune response of hemophilia A patients to administered FVIII is a major complication that obviates this very therapy. We have recently described the use of synthetic, biodegradable nanoparticles carrying rapamycin and FVIII peptide antigens, to induce antigen-specific tolerance. Herein we test the tolerogenicity of nanoparticles that contains full length FVIII protein in hemophilia A mice, focusing on anti-FVIII humoral immune response. As expected, recipients of tolerogenic nanoparticles remained unresponsive to FVIII despite multiple challenges for up to 6months. Furthermore, therapeutic treatments in FVIII-immunized mice with pre-existing anti-FVIII antibodies resulted in diminished antibody titers, albeit efficacy required longer therapy with the tolerogenic nanoparticles. Interestingly, durable FVIII-specific tolerance was also achieved in animals co-administered with FVIII admixed with nanoparticles encapsulating rapamycin alone. These results suggest that nanoparticles carrying rapamycin and FVIII can be employed to induce specific tolerance to prevent and even reverse inhibitor formation. PMID:26687613

  17. 5-Lipoxygenase inhibitors suppress RANKL-induced osteoclast formation via NFATc1 expression.

    PubMed

    Kang, Ju-Hee; Ting, Zheng; Moon, Mi-Ran; Sim, Jung-Seon; Lee, Jung-Min; Doh, Kyung-Eun; Hong, Sunhye; Cui, Minghua; Choi, Sun; Chang, Hyeun Wook; Park Choo, Hea-Young; Yim, Mijung

    2015-11-01

    5-Lipoxygenase synthesizes leukotrienes from arachidonic acid. We developed three novel 5-LO inhibitors having a benzoxazole scaffold as a potential anti-osteoclastogenics. They significantly suppressed RANKL-induced osteoclast formation in mouse bone marrow-derived macrophages. Furthermore, one compound, K7, inhibited the bone resorptive activity of osteoclasts. The anti-osteoclastogenic effect of K7 was mainly attributable to reduction in the expression of NFATc1, an essential transcription factor for osteoclast differentiation. K7 inhibited osteoclast formation via ERK and p38 MAPK, as well as NF-?B signaling pathways. K7 reduced lipopolysaccharide (LPS)-induced osteoclast formation in vivo, corroborating the in vitro data. Thus, K7 exerted an inhibitory effect on osteoclast formation in vitro and in vivo, properties that make it a potential candidate for the treatment of bone diseases associated with excessive bone resorption. PMID:26432605

  18. Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE₂ induced pain model.

    PubMed

    Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D; da Silva, Carlos Antonio Trindade; Morisseau, Christophe; Hammock, Bruce D

    2015-12-15

    Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3mg/kg/day, p.o.) and OME (100mg/kg/day, p.o., 7 days)+TPPU (3mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE2 was monitored. While OME treatment by itself exhibited variable effects on PGE2 induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME+TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. PMID:26522832

  19. Identification of H7 as a novel peroxiredoxin I inhibitor to induce differentiation of leukemia cells.

    PubMed

    Wei, Wei; Ma, Chunmin; Cao, Yang; Yang, Li; Huang, Zhimin; Qin, Dongjun; Chen, Yingyi; Liu, Chuanxu; Xia, Li; Wang, Tongdan; Lei, Hu; Yu, Yun; Huang, Min; Tong, Yin; Xu, Hanzhang; Gao, Fenghou; Zhang, Jian; Wu, Ying-Li

    2016-01-26

    Identifying novel targets to enhance leukemia-cell differentiation is an urgent requirement. We have recently proposed that inhibiting the antioxidant enzyme peroxiredoxin I (Prdx I) may induce leukemia-cell differentiation. However, this concept remains to be confirmed. In this work, we identified H7 as a novel Prdx I inhibitor through virtual screening, in vitro activity assay, and surface plasmon resonance assay. Cellular thermal shift assay showed that H7 directly bound to Prdx I but not to Prdxs II-V in cells. H7 treatment also increased reactive oxygen species (ROS) level and cell differentiation in leukemia cells, as reflected by the upregulation of the cell surface differentiation marker CD11b/CD14 and the morphological maturation of cells. The differentiation-induction effect of H7 was further observed in some non-acute promyelocytic leukemia (APL) and primary leukemia cells apart from APL NB4 cells. Moreover, the ROS scavenger N-acetyl cysteine significantly reversed the H7-induced cell differentiation. We demonstrated as well that H7-induced cell differentiation was associated with the activation of the ROS-Erk1/2-C/EBPβ axis. Finally, we showed H7 treatment induced cell differentiation in an APL mouse model. All of these data confirmed that Prdx I was novel target for inducing leukemia-cell differentiation and that H7 was a novel lead compound for optimizing Prdx I inhibition. PMID:26716647

  20. Efficacy of Rho kinase inhibitor on cognitive impairment induced by chronic cerebral hypoperfusion in rats.

    PubMed

    Zhang, Qiang; Zhang, Jun-Jian; Han, Zhong-Mou

    2015-01-01

    This work aims to explore the efficacy of Rho kinase inhibitor Fasudil on cognitive impairment induced by chronic cerebral hypoperfusion in rats. A total of 32 male adult Sprague Dawley (SD) rats were randomly divided into three groups: treatment group, control group and sham-operated group for severe carotid artery stenosis model. After two weeks, 8.35 mg/kg Fasudil and physiological saline were intraperitoneally applied twice per day in treatment group and control group, respectively. Morris water maze test was performed in each group to detect the changes of cognitive function and observe the hippocampal pathomorphology in rats after eight weeks. The average escape latency distinctly shortened (P < 0.01) and the percentage of swimming distance in the platform quadrant significantly increased (P < 0.01) in treatment group compared with those at corresponding time points in control group. The rate of carotid artery stenosis in rats had no statistical difference between treatment and control groups (P > 0.05). Fasudil effectively improved hippocampal pathomorphology. Rho kinase inhibitor obviously ameliorated cognitive impairment induced by chronic cerebral hypoperfusion in rats. PMID:25932185

  1. Sorafenib, a multikinase inhibitor, induces formation of stress granules in hepatocarcinoma cells

    PubMed Central

    Adjibade, Pauline; St-Sauveur, Valérie Grenier; Huberdeau, Miguel Quevillon; Fournier, Marie-Josée; Savard, Andreanne; Coudert, Laetitia; Khandjian, Edouard W.; Mazroui, Rachid

    2015-01-01

    Stress granules (SGs) are cytoplasmic RNA multimeric bodies that form under stress conditions known to inhibit translation initiation. In most reported stress cases, the formation of SGs was associated with the cell recovery from stress and survival. In cells derived from cancer, SGs formation was shown to promote resistance to either proteasome inhibitors or 5-Fluorouracil used as chemotherapeutic agents. Despite these studies, the induction of SGs by chemotherapeutic drugs contributing to cancer cells resistance is still understudied. Here we identified sorafenib, a tyrosine kinase inhibitor used to treat hepatocarcinoma, as a potent chemotherapeutic inducer of SGs. The formation of SGs in sorafenib-treated hepatocarcionoma cells correlates with inhibition of translation initiation; both events requiring the phosphorylation of the translation initiation factor eIF2α. Further characterisation of the mechanism of sorafenib-induced SGs revealed PERK as the main eIF2α kinase responsible for SGs formation. Depletion experiments support the implication of PERK-eIF2α-SGs pathway in hepatocarcinoma cells resistance to sorafenib. This study also suggests the existence of an unexpected complex regulatory balance between SGs and phospho-eIF2α where SGs dampen the activation of the phospho-eIF2α-downstream ATF4 cell death pathway. PMID:26556863

  2. Efficacy of Rho kinase inhibitor on cognitive impairment induced by chronic cerebral hypoperfusion in rats

    PubMed Central

    Zhang, Qiang; Zhang, Jun-Jian; Han, Zhong-Mou

    2015-01-01

    This work aims to explore the efficacy of Rho kinase inhibitor Fasudil on cognitive impairment induced by chronic cerebral hypoperfusion in rats. A total of 32 male adult Sprague Dawley (SD) rats were randomly divided into three groups: treatment group, control group and sham-operated group for severe carotid artery stenosis model. After two weeks, 8.35 mg/kg Fasudil and physiological saline were intraperitoneally applied twice per day in treatment group and control group, respectively. Morris water maze test was performed in each group to detect the changes of cognitive function and observe the hippocampal pathomorphology in rats after eight weeks. The average escape latency distinctly shortened (P < 0.01) and the percentage of swimming distance in the platform quadrant significantly increased (P < 0.01) in treatment group compared with those at corresponding time points in control group. The rate of carotid artery stenosis in rats had no statistical difference between treatment and control groups (P > 0.05). Fasudil effectively improved hippocampal pathomorphology. Rho kinase inhibitor obviously ameliorated cognitive impairment induced by chronic cerebral hypoperfusion in rats. PMID:25932185

  3. Sorafenib, a multikinase inhibitor, induces formation of stress granules in hepatocarcinoma cells.

    PubMed

    Adjibade, Pauline; St-Sauveur, Valrie Grenier; Quevillon Huberdeau, Miguel; Fournier, Marie-Jose; Savard, Andreanne; Coudert, Laetitia; Khandjian, Edouard W; Mazroui, Rachid

    2015-12-22

    Stress granules (SGs) are cytoplasmic RNA multimeric bodies that form under stress conditions known to inhibit translation initiation. In most reported stress cases, the formation of SGs was associated with the cell recovery from stress and survival. In cells derived from cancer, SGs formation was shown to promote resistance to either proteasome inhibitors or 5-Fluorouracil used as chemotherapeutic agents. Despite these studies, the induction of SGs by chemotherapeutic drugs contributing to cancer cells resistance is still understudied. Here we identified sorafenib, a tyrosine kinase inhibitor used to treat hepatocarcinoma, as a potent chemotherapeutic inducer of SGs. The formation of SGs in sorafenib-treated hepatocarcionoma cells correlates with inhibition of translation initiation; both events requiring the phosphorylation of the translation initiation factor eIF2?. Further characterisation of the mechanism of sorafenib-induced SGs revealed PERK as the main eIF2? kinase responsible for SGs formation. Depletion experiments support the implication of PERK-eIF2?-SGs pathway in hepatocarcinoma cells resistance to sorafenib. This study also suggests the existence of an unexpected complex regulatory balance between SGs and phospho-eIF2? where SGs dampen the activation of the phospho-eIF2?-downstream ATF4 cell death pathway. PMID:26556863

  4. Farnesyltransferase Inhibitor, Tipifarnib, Prevents Galactosamine/Lipopolysaccharide-Induced Acute Liver Failure

    PubMed Central

    Shirozu, Kazuhiro; Hirai, Shuichi; Tanaka, Tomokazu; Hisaka, Shinsuke

    2014-01-01

    Acute liver failure (ALF) is a fatal syndrome associated with massive hepatocyte death. There is no cure for ALF except liver transplantation. Protein farnesylation is a lipid modification of cysteine residues that is catalyzed by farnesyltransferase (FTase) and has been proposed as an integral component of acute inflammation. Previously, we have demonstrated that FTase inhibitors improve survival in mouse models of endotoxemia and sepsis. Here we studied the effects of FTase inhibitor, tipifarnib, on galactosamine (GalN) /lipopolysaccharide (LPS)-induced acute liver failure. The effects of tipifarnib (10 mg/kg, IP) were studied in GalN (400 mg/kg, IP) and LPS (3 ?g/kg)-challenged mice by histological and biochemical analyses. GalN/LPS administration caused prominent liver injury characterized by the increased plasma alanine aminotransferase (ALT) and aspartic aminotransferase (AST) levels leading to significant mortality in mice. Tipifarnib inhibited GalN/LPS-induced caspase 3 activation, inflammatory cytokine production, and c-Jun N-terminal Kinase (JNK) phosphorylation in the liver. On the other hand, Tipifarnib upregulated anti-apoptotic protein, Bcl-xL, in the liver after GalN/LPS challenge. Tipifarnib also protected primary hepatocytes from GalN/tumor necrosis factor-? (TNF-?)-induced cell death by inhibiting caspase 3 activation and upregulating anti-apoptotic proteins. GalN/LPS-induced liver injury was associated with increased protein farnesylation in the liver. Tipifarnib prevented protein farnesylation in the liver and markedly attenuated liver injury and mortality in GalN/LPS-challenged mice. These results suggest that protein farnesylation is a novel potential molecular target to prevent hepatocyte death and acute inflammatory liver failure in fulminant hepatitis. PMID:25046541

  5. Induced resistance to methionyl-tRNA synthetase inhibitors in Trypanosoma brucei is due to overexpression of the target.

    PubMed

    Ranade, Ranae M; Gillespie, J Robert; Shibata, Sayaka; Verlinde, Christophe L M J; Fan, Erkang; Hol, Wim G J; Buckner, Frederick S

    2013-07-01

    New classes of antiparasitic drugs active against Trypanosoma brucei are needed to combat human African trypanosomiasis. Inhibitors of methionyl-tRNA synthetase (MetRS) have excellent potential to be developed for this purpose (S. Shibata, J. R. Gillespie, A. M. Kelley, A. J. Napuli, Z. Zhang, K. V. Kovzun, R. M. Pefley, J. Lam, F. H. Zucker, W. C. Van Voorhis, E. A. Merritt, W. G. Hol, C. L. Verlinde, E. Fan, and F. S. Buckner, Antimicrob. Agents Chemother. 55:1982-1989, 2011). In order to assess the potential for resistance to develop against this new class of inhibitors, T. brucei cultures were grown in the presence of MetRS inhibitors or comparison drugs. Resistance up to ?50 times the baseline 50% inhibitory concentration (IC50) was induced against a MetRS inhibitor after ?120 days. A similar level of resistance to the clinical drug eflornithine was induced after ?50 days and for pentamidine after ?80 days. Thus, resistance was induced more slowly against MetRS inhibitors than against clinically used drugs. The parasites resistant to the MetRS inhibitor were shown to overexpress MetRS mRNA by a factor of 35 over the parental strain. Southern analysis indicated that the MetRS gene was amplified in the genome by nearly 8-fold. When injected into mice, the MetRS inhibitor-resistant parasites caused a reduced level of infection, indicating that the changes associated with resistance attenuated their virulence. This finding and the fact that resistance to MetRS inhibitors developed relatively slowly are encouraging for further development of this class of compounds. Published studies on other antitrypanosomal drugs have primarily shown that alterations in membrane transporters were the mechanisms responsible for resistance. This is the first published report of induced drug resistance in the African trypanosome due to overexpression of the target enzyme. PMID:23587950

  6. Induced Resistance to Methionyl-tRNA Synthetase Inhibitors in Trypanosoma brucei Is Due to Overexpression of the Target

    PubMed Central

    Ranade, Ranae M.; Gillespie, J. Robert; Shibata, Sayaka; Verlinde, Christophe L. M. J.; Fan, Erkang; Hol, Wim G. J.

    2013-01-01

    New classes of antiparasitic drugs active against Trypanosoma brucei are needed to combat human African trypanosomiasis. Inhibitors of methionyl-tRNA synthetase (MetRS) have excellent potential to be developed for this purpose (S. Shibata, J. R. Gillespie, A. M. Kelley, A. J. Napuli, Z. Zhang, K. V. Kovzun, R. M. Pefley, J. Lam, F. H. Zucker, W. C. Van Voorhis, E. A. Merritt, W. G. Hol, C. L. Verlinde, E. Fan, and F. S. Buckner, Antimicrob. Agents Chemother. 55:19821989, 2011). In order to assess the potential for resistance to develop against this new class of inhibitors, T. brucei cultures were grown in the presence of MetRS inhibitors or comparison drugs. Resistance up to ?50 times the baseline 50% inhibitory concentration (IC50) was induced against a MetRS inhibitor after ?120 days. A similar level of resistance to the clinical drug eflornithine was induced after ?50 days and for pentamidine after ?80 days. Thus, resistance was induced more slowly against MetRS inhibitors than against clinically used drugs. The parasites resistant to the MetRS inhibitor were shown to overexpress MetRS mRNA by a factor of 35 over the parental strain. Southern analysis indicated that the MetRS gene was amplified in the genome by nearly 8-fold. When injected into mice, the MetRS inhibitor-resistant parasites caused a reduced level of infection, indicating that the changes associated with resistance attenuated their virulence. This finding and the fact that resistance to MetRS inhibitors developed relatively slowly are encouraging for further development of this class of compounds. Published studies on other antitrypanosomal drugs have primarily shown that alterations in membrane transporters were the mechanisms responsible for resistance. This is the first published report of induced drug resistance in the African trypanosome due to overexpression of the target enzyme. PMID:23587950

  7. HIF prolyl hydroxylase inhibitors prevent neuronal death induced by mitochondrial toxins: therapeutic implications for Huntington's disease and Alzheimer's disease.

    PubMed

    Niatsetskaya, Zoya; Basso, Manuela; Speer, Rachel E; McConoughey, Stephen J; Coppola, Giovanni; Ma, Thong C; Ratan, Rajiv R

    2010-04-01

    Mitochondrial dysfunction is a central feature of a number of acute and chronic neurodegenerative conditions, but clinically approved therapeutic interventions are only just emerging. Here we demonstrate the potential clinical utility of low molecular weight inhibitors of the hypoxia inducible factor prolyl-4-hydroxylases (HIF PHDs) in preventing mitochondrial toxin-induced cell death in mouse striatal neurons that express a "knock-in" mutant Huntingtin allele. Protection from 3-nitropropionic acid (3-NP, a complex II inhibitor)-induced toxicity by HIF PHD inhibition occurs without rescue of succinate dehydrogenase activity. Although HIF-1alpha mRNA is dramatically induced by mutant huntingtin, HIF-1alpha depletion by short interfering RNAs (siRNA) does not affect steady-state viability or protection from 3-NP-induced death by HIF PHD inhibitors in these cells. Moreover, 3-NP-induced complex II inhibition in control or mutant striatal neurons does not lead to activation of HIF-dependent transcription. HIF PHD inhibition also protects cortical neurons from 3-NP-induced cytotoxicity. Protection of cortical neurons by HIF PHD inhibition correlates with enhanced VEGF but not PGC-1alpha gene expression. Together, these findings suggest that HIF PHD inhibitors are promising candidates for preventing cell death in conditions such as Huntington's disease and Alzheimer's disease that are associated with metabolic stress in the central nervous system. PMID:19659431

  8. Peroxisome proliferator-activated receptor gamma regulates expression of signal transducer and activator of transcription 5A

    SciTech Connect

    Olsen, Hanne; Haldosen, Lars-Arne . E-mail: Lars-Arne.Haldosen@mednut.ki.se

    2006-05-01

    Signal transducer and activator of transcription 5A (STAT5A) has been shown to be important for terminal differentiation of mammary epithelial cells. In order to understand regulation of expression of STAT5A, the 5' end of the mouse Stat5a gene was isolated. Putative regulatory elements was searched for and several peroxisome proliferator response elements (PPREs) were found, one with high (12/13 nucleotides) and three with less (8-10/13) similarity to the reported consensus sequence. Mouse mammary epithelial HC11 cells were treated with peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) ligand, the thiazolidinedione (TZD) troglitazone, and an increase in STAT5A protein expression was seen. The 5' flank of Stat5a gene was cloned in a luciferase reporter vector. A concentration dependent activation of the STAT5A-luciferase reporter was detected, when transiently transfected HC11 cells were treated with TZD. The activation could be inhibited by treatment with a PPAR{gamma} antagonist. It has earlier been shown that epidermal growth factor (EGF) induces MAPK phosphorylation of PPAR{gamma} resulting in a less transcriptionally active receptor. In HC11 cells, EGF inhibited TZD induced STAT5A-reporter activity suggesting that our previously reported EGF-mediated suppression of STAT5A expression is mediated in all or partly through inhibition of PPAR{gamma} activity. Furthermore, the MEK inhibitor PD98059 inhibited the EGF effect. All together, data presented suggest that PPAR{gamma} participates in regulation of STAT5A expression.

  9. Effect of the Angiotensin I Converting Enzyme Inhibitor, MK-421, on Experimentally Induced Drinking

    NASA Technical Reports Server (NTRS)

    Fregley, Melvin J.; Fater, Dennis C.; Greenleaf, John E.

    1982-01-01

    MK-421, the ethyl ester maleate salt of N-(S)-1-(ethoxycarbonyl)-3-phenyl-propyl- Ala-L-Pro, is an angiotensin I converting enzyme inhibitor. An initial objective was to determine whether MK-421, administered at 0, 2.5, 5.0, 10.0, 20.0 and 40.0 mg/kg, ip to 96 female rats 15 min prior to administration of the beta-adrenergic agonist, isoproterenol (25 microgram/kg, ip), would inhibit the drinking induced by isoproterenol during 2 h after its administration. The water intake induced by isoproterenol was inhibited significantly by 2.5 mg MK-421/kg. When a similar experiment was performed using Angiotensin I (AI) (200 microgram/kg, ip) as the dipsogenic agent, MK-421 (5 mg/kg, ip), administered 15 min prior to AI, inhibited significantly both the dipsogenic and the diuretic effect of AI. However, administration of angiotensin II (AII, 200 microgram/kg, ip) 15 min after MK-421 (5mg/kg) was accompanied by a water intake that did not differ from AII alone. The drink induced by ip administration of 1.0 m NaCl solution (1% of body wt, ip) was not inhibited by administration of MK-421 (5 mg/kg) 15 min prior to allowing access to water while the drink induced by a 24 h dehydration was partially inhibited. Thus, the drinks induced by administraition of either isoproterenol or AI are dependent on formation of AII. That induced by dehydration is partially dependent, while that induced by hypertonic siilinc is independent of the formation of AII.

  10. A rat retinal damage model predicts for potential clinical visual disturbances induced by Hsp90 inhibitors

    SciTech Connect

    Zhou, Dan; Liu, Yuan; Ye, Josephine; Ying, Weiwen; Ogawa, Luisa Shin; Inoue, Takayo; Tatsuta, Noriaki; Wada, Yumiko; Koya, Keizo; Huang, Qin; Bates, Richard C.; Sonderfan, Andrew J.

    2013-12-01

    In human trials certain heat shock protein 90 (Hsp90) inhibitors, including 17-DMAG and NVP-AUY922, have caused visual disorders indicative of retinal dysfunction; others such as 17-AAG and ganetespib have not. To understand these safety profile differences we evaluated histopathological changes and exposure profiles of four Hsp90 inhibitors, with or without clinical reports of adverse ocular effects, using a rat retinal model. Retinal morphology, Hsp70 expression (a surrogate marker of Hsp90 inhibition), apoptotic induction and pharmacokinetic drug exposure analysis were examined in rats treated with the ansamycins 17-DMAG and 17-AAG, or with the second-generation compounds NVP-AUY922 and ganetespib. Both 17-DMAG and NVP-AUY922 induced strong yet restricted retinal Hsp70 up-regulation and promoted marked photoreceptor cell death 24 h after the final dose. In contrast, neither 17-AAG nor ganetespib elicited photoreceptor injury. When the relationship between drug distribution and photoreceptor degeneration was examined, 17-DMAG and NVP-AUY922 showed substantial retinal accumulation, with high retina/plasma (R/P) ratios and slow elimination rates, such that 51% of 17-DMAG and 65% of NVP-AUY922 present at 30 min post-injection were retained in the retina 6 h post-dose. For 17-AAG and ganetespib, retinal elimination was rapid (90% and 70% of drugs eliminated from the retina at 6 h, respectively) which correlated with lower R/P ratios. These findings indicate that prolonged inhibition of Hsp90 activity in the eye results in photoreceptor cell death. Moreover, the results suggest that the retina/plasma exposure ratio and retinal elimination rate profiles of Hsp90 inhibitors, irrespective of their chemical class, may predict for ocular toxicity potential. - Highlights: • In human trials some Hsp90 inhibitors cause visual disorders, others do not. • Prolonged inhibition of Hsp90 in the rat eye results in photoreceptor cell death. • Retina/plasma ratio and retinal elimination rate are linked to toxicity potential. • Rat retinotoxic responses to individual Hsp90 inhibitors reflect clinical profiles. • Rodent modeling may be used to assess ocular risks of targeted Hsp90 compounds.

  11. Localization of a portion of the liver isoform of fatty-acid-binding protein (L-FABP) to peroxisomes.

    PubMed

    Antonenkov, Vasily D; Sormunen, Raija T; Ohlmeier, Steffen; Amery, Leen; Fransen, Marc; Mannaerts, Guy P; Hiltunen, J Kalervo

    2006-03-01

    The liver isoform of fatty-acid-binding protein (L-FABP) facilitates the cellular uptake, transport and metabolism of fatty acids and is also involved in the regulation of gene expressions and cell differentiation. Consistent with these functions, L-FABP is predominantly present in the cytoplasm and to a lesser extent in the nucleus; however, a significant portion of this protein has also been detected in fractions containing different organelles. More recent observations, notably on L-FABP-deficient mice, indicated a possible direct involvement of L-FABP in the peroxisomal oxidation of long-chain fatty acids. In order to clarify the links between L-FABP and peroxisomal lipid metabolism, we reinvestigated the subcellular distribution of the protein. Analytical subcellular fractionation by a method preserving the intactness of isolated peroxisomes, two-dimensional gel electrophoresis of peroxisomal matrix proteins combined with MS analysis, and immunoelectron microscopy of liver sections demonstrate the presence of L-FABP in the matrix of peroxisomes as a soluble protein. Peroxisomal L-FABP was highly inducible by clofibrate. The induction of L-FABP was accompanied by a marked increase in the binding capacity of peroxisomal matrix proteins for oleic acid and cis-parinaric acid. The peroxisomal beta-oxidation of palmitoyl-CoA and acyl-CoA thioesterase activity were stimulated by L-FABP, indicating that the protein modulates the function of peroxisomal lipid-metabolizing enzymes. The possible role of intraperoxisomal L-FABP in lipid metabolism is discussed. PMID:16262600

  12. A neutrophil elastase inhibitor prevents bleomycin-induced pulmonary fibrosis in mice.

    PubMed

    Takemasa, Akihiro; Ishii, Yoshiki; Fukuda, Takeshi

    2012-12-01

    Neutrophil elastase plays pivotal roles in the pathogenesis of pulmonary fibrosis. The neutrophil elastase inhibitor, sivelestat, could alleviate pulmonary fibrosis; however, the antifibrotic mechanisms have not yet been clarified. We examined the antifibrotic mechanisms, mainly focusing on a key fibrotic cytokine, transforming growth factor (TGF)-?1, in this study. To elucidate the antifibrotic mechanisms of sivelestat, we examined a murine model of bleomycin-induced early-stage pulmonary fibrosis. After intratracheal instillation of bleomycin, sivelestat was administered intraperitoneally once a day for 7 or 14 days. Bronchoalveolar lavage fluid and lung samples were examined on day 7 or day 14 after bleomycin instillation. In the bleomycin-induced early-stage pulmonary fibrosis model, the neutrophil elastase level was increased in the lungs. Sivelestat significantly inhibited the increase in lung collagen content, fibrotic changes, the numbers of total cells (including macrophages, neutrophils and lymphocytes), the levels of the active form of TGF-?1 and phospho-Smad2 in bleomycin-induced early-stage pulmonary fibrosis. The total TGF-?1 levels and relative changes of TGF-?1 mRNA expression, however, were not decreased significantly by sivelestat. These results suggest that sivelestat alleviated bleomycin-induced pulmonary fibrosis via inhibition of both TGF-? activation and inflammatory cell recruitment in the lung. PMID:22441751

  13. Inter-? inhibitor protein and its associated glycosaminoglycans protect against histone-induced injury.

    PubMed

    Chaaban, Hala; Keshari, Ravi S; Silasi-Mansat, Robert; Popescu, Narcis I; Mehta-D'Souza, Padmaja; Lim, Yow-Pin; Lupu, Florea

    2015-04-01

    Extracellular histones are mediators of tissue injury and organ dysfunction; therefore they constitute potential therapeutic targets in sepsis, inflammation, and thrombosis. Histone cytotoxicity in vitro decreases in the presence of plasma. Here, we demonstrate that plasma inter-? inhibitor protein (IAIP) neutralizes the cytotoxic effects of histones and decreases histone-induced platelet aggregation. These effects are mediated through the negatively charged glycosaminoglycans (GAGs) chondroitin sulfate and high-molecular-weight hyaluronan (HMW-HA) associated with IAIP. Cell surface anionic glycosaminoglycans heparan sulfate and HA protect the cells against histone-mediated damage in vitro. Surface plasmon resonance showed that both IAIP and HMW-HA directly bind to recombinant histone H4. In vivo neutralization of histones with IAIP and HMW-HA prevented histone-induced thrombocytopenia, bleeding, and lung microvascular thrombosis, decreased neutrophil activation, and averted histone-induced production of inflammatory cytokines and chemokines. IAIP and HMW-HA colocalized with histones in necrotic tissues and areas that displayed neutrophil extracellular traps. Increasing amounts of IAIP-histone complexes detected in the plasma of septic baboons correlated with increase in histones and/or nucleosomes and consumption of plasma IAIP. Our data suggest that IAIP, chondroitin sulfate, and HMW-HA are potential therapeutic agents to protect against histone-induced cytotoxicity, coagulopathy, systemic inflammation, and organ damage during inflammatory conditions such as sepsis and trauma. PMID:25631771

  14. Differential sensitivity of ovarian carcinoma cell lines to apoptosis induced by the IMPDH inhibitor benzamide riboside.

    PubMed

    Hunkov, L; Bies, J; Sedlk, J; Duraj, J; Jakubkov, J; Takcsov, X; Novotn, L; Chorvth, B

    2000-01-01

    The differential sensitivity of examined human ovarian carcinoma cell lines (CH1, A-2780 and SKOV-3) to the IMPDH inhibitor, benzamide riboside (BR), was demonstrated with the aid of MTT assay. Present data show that all three examined ovarian carcinoma cell lines were sensitive to the cytotoxic effects of BR in the order of sensitivity CH1, SKOV-3, A-2780, (IC50 = 2.8, 4.0 and 7.4 microM, respectively). Although the IC50 of SKOV-3 cells was similar to that previously determined by others, more than 20% of SKOV-3 cells remained viable in a plateau up to 40 microM BR concentration. This relative resistance of SKOV-3 cells to BR corresponded to the absence ofBR-induced apoptosis in SKOV-3 cells, which together with clearly demonstrated sensitivity of CH1 cells to BR-induced apoptosis, established by flow cytometry (presence of nuclei with sub-G0 DNA content, Annexin V binding) and western blotting (poly-ADP-ribosyl-polymerase (PARP) cleavage), further stressed the role of drug-induced apoptosis in the over-all drug-induced cytotoxicity. PMID:11130242

  15. B-Raf inhibitors induce epithelial differentiation in BRAF-mutant colorectal cancer cells.

    PubMed

    Herr, Ricarda; Khler, Martin; Andrlov, Hana; Weinberg, Florian; Mller, Yvonne; Halbach, Sebastian; Lutz, Lisa; Mastroianni, Justin; Klose, Martin; Bittermann, Nicola; Kowar, Silke; Zeiser, Robert; Olayioye, Monilola A; Lassmann, Silke; Busch, Hauke; Boerries, Melanie; Brummer, Tilman

    2015-01-01

    BRAF mutations are associated with aggressive, less-differentiated and therapy-resistant colorectal carcinoma. However, the underlying mechanisms for these correlations remain unknown. To understand how oncogenic B-Raf contributes to carcinogenesis, in particular to aspects other than cellular proliferation and survival, we generated three isogenic human colorectal carcinoma cell line models in which we can dynamically modulate the expression of the B-Raf(V600E) oncoprotein. Doxycyclin-inducible knockdown of endogenous B-Raf(V600E) decreases cellular motility and invasion in conventional and three-dimensional (3D) culture, whereas it promotes cell-cell contacts and induces various hallmarks of differentiated epithelia. Importantly, all these effects are recapitulated by B-Raf (PLX4720, vemurafenib, and dabrafenib) or MEK inhibitors (trametinib). Surprisingly, loss of B-Raf(V600E) in HT29 xenografts does not only stall tumor growth, but also induces glandular structures with marked expression of CDX2, a tumor-suppressor and master transcription factor of intestinal differentiation. By performing the first transcriptome profiles of PLX4720-treated 3D cultures of HT29 and Colo-205 cells, we identify several upregulated genes linked to epithelial differentiation and effector functions, such as claudin-1, a Cdx-2 target gene encoding a critical tight junction component. Thereby, we provide a mechanism for the clinically observed correlation between mutant BRAF and the loss of Cdx-2 and claudin-1. PLX4720 also suppressed several metastasis-associated transcripts that have not been implicated as targets, effectors or potential biomarkers of oncogenic B-Raf signaling so far. Together, we identify a novel facet of clinically applied B-Raf or MEK inhibitors by showing that they promote cellular adhesion and differentiation of colorectal carcinoma cells. PMID:25381152

  16. EGF receptor tyrosine kinase inhibitors diminish transforming growth factor-alpha-induced pulmonary fibrosis.

    PubMed

    Hardie, William D; Davidson, Cynthia; Ikegami, Machiko; Leikauf, George D; Le Cras, Timothy D; Prestridge, Adrienne; Whitsett, Jeffrey A; Korfhagen, Thomas R

    2008-06-01

    Transforming growth factor-alpha (TGF-alpha) is a ligand for the EGF receptor (EGFR). EGFR activation is associated with fibroproliferative processes in human lung disease and animal models of pulmonary fibrosis. We determined the effects of EGFR tyrosine kinase inhibitors gefitinib (Iressa) and erlotinib (Tarceva) on the development and progression of TGF-alpha-induced pulmonary fibrosis. Using a doxycycline-regulatable transgenic mouse model of lung-specific TGF-alpha expression, we determined effects of treatment with gefitinib and erlotinib on changes in lung histology, total lung collagen, pulmonary mechanics, pulmonary hypertension, and expression of genes associated with synthesis of ECM and vascular remodeling. Induction in the lung of TGF-alpha caused progressive pulmonary fibrosis over an 8-wk period. Daily administration of gefitinib or erlotinib prevented development of fibrosis, reduced accumulation of total lung collagen, prevented weight loss, and prevented changes in pulmonary mechanics. Treatment of mice with gefitinib 4 wk after the induction of TGF-alpha prevented further increases in and partially reversed total collagen levels and changes in pulmonary mechanics and pulmonary hypertension. Increases in expression of genes associated with synthesis of ECM as well as decreases of genes associated with vascular remodeling were also prevented or partially reversed. Administration of gefitinib or erlotinib did not cause interstitial fibrosis or increases in lavage cell counts. Administration of small molecule EGFR tyrosine kinase inhibitors prevented further increases in and partially reversed pulmonary fibrosis induced directly by EGFR activation without inducing inflammatory cell influx or additional lung injury. PMID:18424623

  17. Isoflurane-Induced Spatial Memory Impairment in Mice is Prevented by the Acetylcholinesterase Inhibitor Donepezil

    PubMed Central

    Wang, Beilei; Xu, Huan; Li, Wen; Chen, Jie; Wang, Xiangrui

    2011-01-01

    Although many studies have shown that isoflurane exposure impairs spatial memory in aged animals, there are no clinical treatments available to prevent this memory deficit. The anticholinergic properties of volatile anesthetics are a biologically plausible cause of cognitive dysfunction in elderly subjects. We hypothesized that pretreatment with the acetylcholinesterase inhibitor donepezil, which has been approved by the Food and Drug Administration (FDA) for the treatment of Alzheimer's disease, prevents isoflurane-induced spatial memory impairment in aged mice. In present study, eighteen-month-old mice were administered donepezil (5 mg/kg) or an equal volume of saline by oral gavage with a feeding needle for four weeks. Then the mice were exposed to isoflurane (1.2%) for six hours. Two weeks later, mice were subjected to the Morris water maze to examine the impairment of spatial memory after exposure to isoflurane. After the behavioral test, the mice were sacrificed, and the protein expression level of acetylcholinesterase (AChE), choline acetylase (ChAT) and ?7 nicotinic receptor (?7-nAChR) were measured in the brain. Each group consisted of 12 mice. We found that isoflurane exposure for six hours impaired the spatial memory of the mice. Compared with the control group, isoflurane exposure dramatically decreased the protein level of ChAT, but not AChE or ?7-nAChR. Donepezil prevented isoflurane-induced spatial memory impairments and increased ChAT levels, which were downregulated by isoflurane. In conclusions, pretreatment with the AChE inhibitor donepezil prevented isoflurane-induced spatial memory impairment in aged mice. The mechanism was associated with the upregulation of ChAT, which was decreased by isoflurane. PMID:22114680

  18. Role of Pex21p for Piggyback Import of Gpd1p and Pnc1p into Peroxisomes of Saccharomyces cerevisiae.

    PubMed

    Effelsberg, Daniel; Cruz-Zaragoza, Luis Daniel; Tonillo, Jason; Schliebs, Wolfgang; Erdmann, Ralf

    2015-10-16

    Proteins designated for peroxisomal protein import harbor one of two common peroxisomal targeting signals (PTS). In the yeast Saccharomyces cerevisiae, the oleate-induced PTS2-dependent import of the thiolase Fox3p into peroxisomes is conducted by the soluble import receptor Pex7p in cooperation with the auxiliary Pex18p, one of two supposedly redundant PTS2 co-receptors. Here, we report on a novel function for the co-receptor Pex21p, which cannot be fulfilled by Pex18p. The data establish Pex21p as a general co-receptor in PTS2-dependent protein import, whereas Pex18p is especially important for oleate-induced import of PTS2 proteins. The glycerol-producing PTS2 protein glycerol-3-phosphate dehydrogenase Gpd1p shows a tripartite localization in peroxisomes, in the cytosol, and in the nucleus under osmotic stress conditions. We show the following: (i) Pex21p is required for peroxisomal import of Gpd1p as well as a key enzyme of the NAD(+) salvage pathway, Pnc1p; (ii) Pnc1p, a nicotinamidase without functional PTS2, is co-imported into peroxisomes by piggyback transport via Gpd1p. Moreover, the specific transport of these two enzymes into peroxisomes suggests a novel regulatory role for peroxisomes under various stress conditions. PMID:26276932

  19. Developmental Roles of D-bifunctional Protein-A Zebrafish Model of Peroxisome Dysfunction

    PubMed Central

    Kim, Yong-Il; Bhandari, Sushil; Lee, Joon No; Yoo, Kyeong-Won; Kim, Se-Jin; Oh, Gi-Su; Kim, Hyung-Jin; Cho, Meyoung; Kwak, Jong-Young; So, Hong-Seob; Park, Raekil; Choe, Seong-Kyu

    2014-01-01

    The peroxisome is an intracellular organelle that responds dynamically to environmental changes. Various model organisms have been used to study the roles of peroxisomal proteins in maintaining cellular homeostasis. By taking advantage of the zebrafish model whose early stage of embryogenesis is dependent on yolk components, we examined the developmental roles of the D-bifunctional protein (Dbp), an essential enzyme in the peroxisomal ?-oxidation. The knockdown of dbp in zebrafish phenocopied clinical manifestations of its deficiency in human, including defective craniofacial morphogenesis, growth retardation, and abnormal neuronal development. Overexpression of murine Dbp rescued the morphological phenotypes induced by dbp knockdown, indicative of conserved roles of Dbp during zebrafish and mammalian development. Knockdown of dbp impaired normal development of blood, blood vessels, and most strikingly, endoderm-derived organs including the liver and pancreas - a phenotype not reported elsewhere in connection with peroxisome dysfunction. Taken together, our results demonstrate for the first time that zebrafish might be a useful model animal to study the role of peroxisomes during vertebrate development. PMID:24552713

  20. Investigation of the molecular mechanisms preceding PDE4 inhibitor-induced vasculopathy in rats: tissue inhibitor of metalloproteinase 1, a potential predictive biomarker.

    PubMed

    Dagus, Nicolas; Pawlowski, Valrie; Sobry, Ccile; Hanton, Gilles; Borde, Franoise; Soler, Sylvain; Freslon, Jean-Louis; Chevalier, Stephan

    2007-11-01

    Phosphodiesterase (PDE) 4 inhibitors are a class of drugs that can provide novel therapies for asthma and chronic obstructive pulmonary disease. Their development is frequently hampered by the induction of vascular toxicity in rat mesenteric tissue during preclinical studies. Whereas these vascular lesions in rats have been well characterized histologically, little is known about their pathogenesis and in turn, sensitive and specific biomarkers for preclinical and clinical monitoring do not exist. In order to investigate the early molecular mechanisms underlying vascular injury, time-course studies were performed by treating rats for 2-24 h with high doses of the PDE4 inhibitor CI-1044. Transcriptomics analyses in mesenteric tissue were performed using oligonucleotide microarray and real-time RT-PCR technologies and compared to histopathological observations. In addition, protein measurements were performed in serum samples to identify soluble biomarkers of vascular injury. Our results indicate that molecular alterations preceded the histological observations of inflammatory and necrotic lesions in mesenteric arteries. Some gene expression changes suggest that the development of the lesions could follow a primary modulation of the vascular tone in response to the pharmacological effect of the compound. Activation of genes coding for pro- and antioxidant enzymes, cytokines, adhesion molecules, and tissue inhibitor of metalloproteinase 1 (TIMP-1) indicates that biomechanical stimuli may contribute to vascular oxidant stress, inflammation, and tissue remodeling. TIMP-1 appeared to be an early and sensitive predictive biomarker of the inflammatory and the tissue remodeling components of PDE4 inhibitor-induced vascular injury. PMID:17569694

  1. Structural biology of the import pathways of peroxisomal matrix proteins.

    PubMed

    Emmanouilidis, Leonidas; Gopalswamy, Mohanraj; Passon, Daniel M; Wilmanns, Matthias; Sattler, Michael

    2016-05-01

    The peroxisomal proteins (peroxins) that mediate the import of peroxisomal matrix proteins have been identified. Recently, the purification of a functional peroxisomal translocon has been reported. However, the molecular details of the import pathways and the mechanisms by which the cargo is translocated into the lumen of the organelle are still poorly understood. Structural studies have begun to provide insight into molecular mechanisms of peroxisomal import pathways for cargo proteins that harbor peroxisomal targeting signals, PTS1 and PTS2, at their C- and N-termini, respectively. So far structures have been reported for binary or tertiary protein-protein interfaces, and highlight the role of intrinsically disordered regions for these interactions. Here, we provide an overview of the currently available structural biology of peroxisomal import pathways. Current challenges and future perspectives of the structural biology of peroxisomal protein translocation are discussed. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26450166

  2. Ubiquitin in the peroxisomal protein import pathway.

    PubMed

    Francisco, Tnia; Rodrigues, Tony A; Pinto, Manuel P; Carvalho, Andreia F; Azevedo, Jorge E; Grou, Cludia P

    2014-03-01

    PEX5 is the shuttling receptor for newly synthesized peroxisomal matrix proteins. Alone, or with the help of an adaptor protein, this receptor binds peroxisomal matrix proteins in the cytosol and transports them to the peroxisomal membrane docking/translocation module (DTM). The interaction between cargo-loaded PEX5 and the DTM ultimately results in its insertion into the DTM with the concomitant translocation of the cargo protein across the organelle membrane. PEX5 is not consumed in this event; rather it is dislocated back into the cytosol so that it can promote additional rounds of protein transportation. Remarkably, the data collected in recent years indicate that dislocation is preceded by monoubiquitination of PEX5 at a conserved cysteine residue. This mandatory modification is not the only type of ubiquitination occurring at the DTM. Indeed, several findings suggest that defective receptors jamming the DTM are polyubiquitinated and targeted to the proteasome for degradation. PMID:23954799

  3. Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram

    SciTech Connect

    Chang, Weiyuan; Chen, Jing; Schlueter, Connie F.; Rando, Roy J.; Pathak, Yashwant V.; Hoyle, Gary W.

    2012-09-01

    Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. -- Highlights: ► Chlorine causes lung injury when inhaled and is considered a chemical threat agent. ► Rolipram inhibited chlorine-induced pulmonary edema and airway hyperreactivity. ► Post-exposure rolipram treatments by both systemic and local delivery were effective. ► Rolipram shows promise as a rescue treatment for chlorine-induced lung injury.

  4. IDENTIFICATION OF EARLY MOLECULAR EVENTS AFTER PEROXISOME PROLIFERATOR EXPOSURE IN THE RODENT LIVER

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor α(PPARα). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPARα but do...

  5. PPAR-DEPENDENT GENE EXPRESSION CHANGES IN THE MOUSE LIVER AFTER EXPOSURE TO PEROXISOME PROLIFERATORS

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor (PPAR?). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPAR&#...

  6. Diabetes or peroxisome proliferator-activated receptor alpha agonist increases mitochondrial thioesterase I activity in heart

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peroxisome proliferator-activated receptor alpha (PPAR alpha) is a transcriptional regulator of the expression of mitochondrial thioesterase I (MTE-I) and uncoupling protein 3 (UCP3), which are induced in the heart at the mRNA level in response to diabetes. Little is known about the regulation of pr...

  7. PPARÁ-DEPENDENT GENE EXPRESSION CHANGES IN THE MOUSE LIVER AFTER EXPOSURE TO PEROXISOME PROLIFERATORS

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor ¿ (PPARα). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPAR&#...

  8. IDENTIFICATION OF EARLY MOLECULAR EVENTS AFTER PEROXISOME PROLIFERATOR EXPOSURE IN THE RODENT LIVER

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor ?(PPAR?). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPAR? but do...

  9. Peroxisome proliferator-activated receptors for hypertension.

    PubMed

    Usuda, Daisuke; Kanda, Tsugiyasu

    2014-08-26

    Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear receptor superfamily, which is composed of four members encoded by distinct genes (α, β, γ, and δ). The genes undergo transactivation or transrepression under specific mechanisms that lead to the induction or repression of target gene expression. As is the case with other nuclear receptors, all four PPAR isoforms contain five or six structural regions in four functional domains; namely, A/B, C, D, and E/F. PPARs have many functions, particularly functions involving control of vascular tone, inflammation, and energy homeostasis, and are, therefore, important targets for hypertension, obesity, obesity-induced inflammation, and metabolic syndrome in general. Hence, PPARs also represent drug targets, and PPARα and PPARγ agonists are used clinically in the treatment of dyslipidemia and type 2 diabetes mellitus, respectively. Because of their pleiotropic effects, they have been identified as active in a number of diseases and are targets for the development of a broad range of therapies for a variety of diseases. It is likely that the range of PPARγ agonist therapeutic actions will result in novel approaches to lifestyle and other diseases. The combination of PPARs with reagents or with other cardiovascular drugs, such as diuretics and angiotensin II receptor blockers, should be studied. This article provides a review of PPAR isoform characteristics, a discussion of progress in our understanding of the biological actions of PPARs, and a summary of PPAR agonist development for patient management. We also include a summary of the experimental and clinical evidence obtained from animal studies and clinical trials conducted to evaluate the usefulness and effectiveness of PPAR agonists in the treatment of lifestyle-related diseases. PMID:25228953

  10. Structures of Helicobacter pylori Shikimate Kinase Reveal a Selective Inhibitor-Induced-Fit Mechanism

    PubMed Central

    Wang, Hung-Jung; Hsu, Kai-Cheng; Lin, Shuang-Chih; Chen, Tzu-Jung; Yang, Jinn-Moon; Wang, Wen-Ching

    2012-01-01

    Shikimate kinase (SK), which catalyzes the specific phosphorylation of the 3-hydroxyl group of shikimic acid in the presence of ATP, is the enzyme in the fifth step of the shikimate pathway for biosynthesis of aromatic amino acids. This pathway is present in bacteria, fungi, and plants but absent in mammals and therefore represents an attractive target pathway for the development of new antimicrobial agents, herbicides, and antiparasitic agents. Here we investigated the detailed structureactivity relationship of SK from Helicobacter pylori (HpSK). Site-directed mutagenesis and isothermal titration calorimetry studies revealed critical conserved residues (D33, F48, R57, R116, and R132) that interact with shikimate and are therefore involved in catalysis. Crystal structures of HpSKSO4, R57A, and HpSKshikimate-3-phosphateADP show a characteristic three-layer architecture and a conformationally elastic region consisting of F48, R57, R116, and R132, occupied by shikimate. The structure of the inhibitor complex, E114A162535, was also determined, which revealed a dramatic shift in the elastic LID region and resulted in conformational locking into a distinctive form. These results reveal considerable insight into the active-site chemistry of SKs and a selective inhibitor-induced-fit mechanism. PMID:22438938

  11. TNF? inhibitor induced lupus-like syndrome (TAILS) in a patient with IBD

    PubMed Central

    LUPU, A.; TIERANU, C.; CONSTANTINESCU, C.L.; DICULESCU, M.

    2014-01-01

    Background: In patients with autoimmune diseases like inflammatory bowel diseases there has been reported a drug-induced lupus like syndrome secondary to TNF? inhibitors. Objective: clinical case presentation and literature review of patients who develop lupus-like syndrome in relation to TNF? antagonists and their future therapeutic options. Materials and methods: we report the case of a 27-year old woman with colonic Crohn's disease on combo-therapy (infliximab+azathioprine) for nearly two years who developed peripheral arthritis and malar rash in the context of TAILS. Results: our patient had positive anti-nuclear antibody, arthritis, malar rash, anemia and leukopenia. Her symptomes remited after discontinuation of infliximab and subsequently she started adalimumab for her Crohn's colitis; more than a year after switching between TNF? inhibitor molecules and stopping azathioprine she is feeling very well. TAILS is a rare condition described in the literature that can affect 0.5-1% of individuals, more often in association with etanercept and infliximab. Several pathogenic routes have been incriminated in the apparition of this syndrome there is still no definite mechanism up to date. Management options include discontinuation of the drug, corticosteroids, hydroxycloroquine sulfate and switching for other immunosupressives. Conclusions: TAILS can appear even a long time after first exposure to TNF? antagonists. In our case, the association with azathioprine was not a primary prophylactic solution. PMID:26788358

  12. Selectively targeting an inactive conformation of interleukin-2-inducible T-cell kinase by allosteric inhibitors.

    PubMed

    Han, Seungil; Czerwinski, Robert M; Caspers, Nicole L; Limburg, David C; Ding, WeiDong; Wang, Hong; Ohren, Jeffrey F; Rajamohan, Francis; McLellan, Thomas J; Unwalla, Ray; Choi, Chulho; Parikh, Mihir D; Seth, Nilufer; Edmonds, Jason; Phillips, Chris; Shakya, Subarna; Li, Xin; Spaulding, Vikki; Hughes, Samantha; Cook, Andrew; Robinson, Colin; Mathias, John P; Navratilova, Iva; Medley, Quintus G; Anderson, David R; Kurumbail, Ravi G; Aulabaugh, Ann

    2014-06-01

    ITK (interleukin-2-inducible T-cell kinase) is a critical component of signal transduction in T-cells and has a well-validated role in their proliferation, cytokine release and chemotaxis. ITK is an attractive target for the treatment of T-cell-mediated inflammatory diseases. In the present study we describe the discovery of kinase inhibitors that preferentially bind to an allosteric pocket of ITK. The novel ITK allosteric site was characterized by NMR, surface plasmon resonance, isothermal titration calorimetry, enzymology and X-ray crystallography. Initial screening hits bound to both the allosteric pocket and the ATP site. Successful lead optimization was achieved by improving the contribution of the allosteric component to the overall inhibition. NMR competition experiments demonstrated that the dual-site binders showed higher affinity for the allosteric site compared with the ATP site. Moreover, an optimized inhibitor displayed non-competitive inhibition with respect to ATP as shown by steady-state enzyme kinetics. The activity of the isolated kinase domain and auto-activation of the full-length enzyme were inhibited with similar potency. However, inhibition of the activated full-length enzyme was weaker, presumably because the allosteric site is altered when ITK becomes activated. An optimized lead showed exquisite kinome selectivity and is efficacious in human whole blood and proximal cell-based assays. PMID:24593284

  13. Optimized Plk1 PBD Inhibitors Based on Poloxin Induce Mitotic Arrest and Apoptosis in Tumor Cells.

    PubMed

    Scharow, Andrej; Raab, Monika; Saxena, Krishna; Sreeramulu, Sridhar; Kudlinzki, Denis; Gande, Santosh; Dtsch, Christina; Kurunci-Csacsko, Elisabeth; Klaeger, Susan; Kuster, Bernhard; Schwalbe, Harald; Strebhardt, Klaus; Berg, Thorsten

    2015-11-20

    Polo-like kinase 1 (Plk1) is a central regulator of mitosis and has been validated as a target for antitumor therapy. The polo-box domain (PBD) of Plk1 regulates its kinase activity and mediates the subcellular localization of Plk1 and its interactions with a subset of its substrates. Functional inhibition of the Plk1 PBD by low-molecular weight inhibitors has been shown to represent a viable strategy by which to inhibit the enzyme, while avoiding selectivity issues caused by the conserved nature of the ATP binding site. Here, we report structure-activity relationships and mechanistic analysis for the first reported Plk1 PBD inhibitor, Poloxin. We present the identification of the optimized analog Poloxin-2, displaying significantly improved potency and selectivity over Poloxin. Poloxin-2 induces mitotic arrest and apoptosis in cultured human tumor cells at low micromolar concentrations, highlighting it as a valuable tool compound for exploring the function of the Plk1 PBD in living cells. PMID:26279064

  14. High Throughput Screening for Small Molecule Inhibitors of Heparin-induced Tau Fibril Formation

    PubMed Central

    Crowe, Alex; Ballatore, Carlo; Hyde, Edward; Trojanowski, John Q.; Lee, Virginia M.-Y.

    2009-01-01

    A library of ?51,000 compounds was interrogated by high throughput screening (HTS) using a heparin-induced tau fibrillization assay. HTS was conducted with bacterially expressed recombinant tau fragment K18 and the reaction was monitored by thioflavine T fluorescence. Hits meeting criteria set for selection in HTS were further evaluated in a panel of assays designed (a) to confirm the initial results and (b) to identify possible false positives arising from non-specific mechanisms or assay dependent artifacts. Two 2,3-di(furan-2-yl)-quinoxalines were confirmed as inhibitors of tau fibrillization with IC50s in the low micromolar range (l3 ?M). Among false positives hits, members of the pyrimidotriazines, benzofurans, porphyrins and anthraquinones, inhibited tau fibrillization by generating peroxides via catalytic redox cycles due to the reducing agent dithiothreitol (DTT) in the assay. This study delineates focused strategies for HTS of tau fibrillization inhibitors that are relevant to drug discovery for Alzheimer's disease and related tauopathies. PMID:17482143

  15. Synthetic peracetate tea polyphenols as potent proteasome inhibitors and apoptosis inducers in human cancer cells.

    PubMed

    Kuhn, Deborah; Lam, Wai Har; Kazi, Aslamuzzaman; Daniel, Kenyon G; Song, Shuojing; Chow, Larry M C; Chan, Tak Hang; Dou, Q Ping

    2005-01-01

    It has been suggested that proteasome activity is essential for tumor cell proliferation and drug resistance development. We have previously shown that natural and synthetic ester bond-containing tea polyphenols are selective inhibitors of the chymotrypsin-like activity of the proteasome. The most abundant catechin in green tea is (-)-epigallocatechin-3-gallate [(-)-EGCG], which has been found by many laboratories to exhibit the most potent anticancer activity. We have reported that (-)-EGCG is also the most effective proteasome inhibitor among all the natural green tea catechins tested. Unfortunately, (-)-EGCG is very unstable in neutral and alkaline conditions. In an attempt to increase the stability and thus the efficacy, we synthesized several (-)-EGCG analogs with acetyl protected -OH groups as prodrugs. Here we report, for the first time, that these acetylated synthetic tea analogs are much more potent than natural (-)-EGCG in inhibiting the proteasome in cultured tumor cells. Consistently, these protected analogs showed much higher potency than (-)-EGCG to inhibit proliferation and transforming activity and to induce apoptosis in human leukemic, prostate, breast, and simian virus 40-transformed cells. Additionally, these protected analogs had greatly reduced effects on human normal and non-transformed cells. Therefore, these peracetate protected tea polyphenols are more efficacious than (-)-EGCG and possess great potential to be developed into novel anticancer drugs. Identification of the cytosolic metabolite(s) of peracetate-protected polyphenols in cultured tumor cells and examination of their in vivo tumor growth-inhibitory activity are currently underway in our laboratory. PMID:15769601

  16. Heat shock protein 90 inhibitors induce functional inhibition of human natural killer cells in a dose-dependent manner.

    PubMed

    Huyan, Ting; Li, Qi; Dong, Dan-Dan; Yang, Hui; Zhang, Jian; Huang, Qing-Sheng; Yin, Da-Chuan; Shang, Peng

    2016-04-01

    Heat shock protein 90 (Hsp90) is a ubiquitously expressed ATP-dependent molecular chaperone across all species that helps to the correct the folding of many proteins related to important signaling pathways. Tumor cells expressing Hsp90 have more ATP-binding affinity than normal cells. Many correlative inhibitors have been developed to promising anti-tumor strategies and have been evaluated in clinical trials. However, the effect of Hsp90 inhibitors on immunocytes cannot be ignored. Natural killer (NK) cells are key components of the innate immune system that play a pivotal role in tumor surveillance. The present study has investigated the potential effect of four Hsp90 inhibitors (NVP-AUY922, BIIB021, 17-DMAG, and SNX-2112) on human primary NK cells. The viability, cytotoxicity, apoptosis, phenotype, and cytokine secretion of NK cells after inhibitor treatment were assessed. The results of this study demonstrated that the inhibitors had negative effects on NK cell activity in a dose-dependent manner. The four inhibitors significantly reduced the cytotoxicity of the NK cells by decreasing viability, inducing apoptosis and down-regulating the expression of cytokines and functional receptors. These findings suggest that more attention should be given to the effect of Hsp90 inhibitors on NK cell function during clinical trials and also represent a potential immunosuppressant strategy. PMID:26642940

  17. Management of diarrhea induced by epidermal growth factor receptor tyrosine kinase inhibitors

    PubMed Central

    Hirsh, V.; Blais, N.; Burkes, R.; Verma, S.; Croitoru, K.

    2014-01-01

    Treatment for non-small-cell lung cancer (nsclc) is moving away from traditional chemotherapy toward personalized medicine. The reversible tyrosine kinase inhibitors (tkis) erlotinib and gefitinib were developed to target the epidermal growth factor receptor (egfr). Afatinib, an irreversible ErbB family blocker, was developed to block egfr (ErbB1), human epidermal growth factor receptor 2 (ErbB2), and ErbB4 signalling, and transphosphorylation of ErbB3. All of the foregoing agents are efficacious in treating nsclc, and their adverse event profile is different from that of chemotherapy. Two of the most common adverse events with egfr tkis are rash and diarrhea. Here, we focus on diarrhea. The key to successful management of diarrhea is to treat early and aggressively using patient education, diet, and antidiarrheal medications such as loperamide. We also present strategies for the effective assessment and management of egfr tki–induced diarrhea. PMID:25489260

  18. Sulfonamides as a new scaffold for hypoxia inducible factor pathway inhibitors.

    PubMed

    Tan, Chalet; de Noronha, Rita G; Devi, Narra S; Jabbar, Adnan A; Kaluz, Stefan; Liu, Yuan; Mooring, Suazette Reid; Nicolaou, K C; Wang, Binghe; Van Meir, Erwin G

    2011-09-15

    Solid tumors generally grow under hypoxic conditions, a pathophysiological change, which activates the expression of genes responsible for malignant, aggressive, and treatment-refractory properties. Hypoxia inducible factor (HIF) is the chief transcription factor regulating hypoxia-driven gene expression. Therefore, the HIF pathway has become a critical target for cancer therapeutics development. We screened a privileged library of about 10,000 natural-product-like compounds using a cell-based assay for HIF-dependent transcriptional activity and identified several arylsulfonamide HIF pathway inhibitors. Among these compounds, the most potent ones showed an IC(50) of ?0.5 ?M in the hypoxia-responsive element (HRE)-luciferase reporter system. Further studies are needed to fully elucidate the mechanism of action of this class of compounds and their structure-activity relationship. PMID:21831638

  19. Proton-pump inhibitor-induced hypomagnesemia: Current research and proposed mechanisms

    PubMed Central

    William, Jeffrey H; Danziger, John

    2016-01-01

    Since the early reports nearly a decade ago, proton-pump inhibitor-induced hypomagnesemia (PPIH) has become a well-recognized phenomenon. While many observational studies in the inpatient and outpatient populations have confirmed the association of PPI exposure and serum magnesium concentrations, there are no prospective, controlled studies to support causation. Molecular mechanisms of magnesium transporters, including the pH-dependent regulation of transient receptor potential melastatin-6 transporters in the colonic enterocyte, have been proposed to explain the effect of PPIs on magnesium reabsorption, but may be a small part of a more complicated interplay of molecular biology, pharmacology, and genetic predisposition. This review explores the current state of research in the field of PPIH and the proposed mechanisms of this effect. PMID:26981439

  20. Phenylbutyrate, a histone deacetylase inhibitor, protects against Adriamycin-induced cardiac injury

    PubMed Central

    Daosukho, Chotiros; Chen, Yumin; Noel, Teresa; Sompol, Pradoldej; Nithipongvanitch, Ramaneeya; Velez, Joyce M.; Oberley, Terry D.; Clair, Daret K. St.

    2007-01-01

    Cardiac injury is a major complication for oxidative stress-generating anticancer agents exemplified by Adriamycin (ADR). Recently, several histone deacetylase inhibitors (HDACIs) including phenylbutyrate (PBA) have shown promise in the treatment of cancer with little known toxicity to normal tissues. PBA has been shown to protect against oxidative stress in normal tissues. Here, we examined whether PBA might protect heart against ADR toxicity in a mouse model. The mice were i.p. injected with ADR (20 mg/kg). PBA (400 mg/kg/day) was i.p. injected one day before and daily after the ADR injection for two days. We found that PBA significantly decreased the ADR-associated elevation of serum lactase dehydrogenase (LDH) and creatine kinase (CK) activities, and diminished ADR-induced ultrastructual damages of cardiac tissue by more than 70%. Importantly, PBA completely rescued ADR-caused reduction of cardiac functions exemplified by ejection fraction and fraction shortening, and increased cardiac MnSOD protein and activity. Our results reveal a previously unrecognized role of HDACIs in protecting against ADR-induced cardiac injury, and suggest that PBA may exert its cardioprotective effect, in part, by the increase of MnSOD. Thus, combining HDACIs with ADR could add a new mechanism to fight cancer while simultaneously decrease ADR-induced cardiotoxicity. PMID:17512461

  1. Histone Deacetylase Inhibitor Trichostatin A Ameliorated Endotoxin-Induced Neuroinflammation and Cognitive Dysfunction

    PubMed Central

    Hsing, Chung-Hsi; Hung, Shih-Kai; Chen, Yeong-Chang; Wei, Tsui-Shan; Sun, Ding-Ping; Wang, Jhi-Joung; Yeh, Ching-Hua

    2015-01-01

    Excessive production of cytokines by microglia may cause cognitive dysfunction and long-lasting behavioral changes. Activating the peripheral innate immune system stimulates cytokine secretion in the central nervous system, which modulates cognitive function. Histone deacetylases (HDACs) modulate cytokine synthesis and release. Trichostatin A (TSA), an HDAC inhibitor, is documented to be anti-inflammatory and neuroprotective. We investigated whether TSA reduces lipopolysaccharide- (LPS-) induced neuroinflammation and cognitive dysfunction. ICR mice were first intraperitoneally (i.p.) injected with vehicle or TSA (0.3?mg/kg). One hour later, they were injected (i.p.) with saline or Escherichia coli LPS (1?mg/kg). We analyzed the food and water intake, body weight loss, and sucrose preference of the injected mice and then determined the microglia activation and inflammatory cytokine expression in the brains of LPS-treated mice and LPS-treated BV-2 microglial cells. In the TSA-pretreated mice, microglial activation was lower, anhedonia did not occur, and LPS-induced cognitive dysfunction (anorexia, weight loss, and social withdrawal) was attenuated. Moreover, mRNA expression of HDAC2, HDAC5, indoleamine 2,3-dioxygenase (IDO), TNF-?, MCP-1, and IL-1? in the brain of LPS-challenged mice and in the LPS-treated BV-2 microglial cells was lower. TSA diminished LPS-induced inflammatory responses in the mouse brain and modulated the cytokine-associated changes in cognitive function, which might be specifically related to reducing HDAC2 and HDAC5 expression. PMID:26273133

  2. Histone Deacetylase Inhibitor Trichostatin A Ameliorated Endotoxin-Induced Neuroinflammation and Cognitive Dysfunction.

    PubMed

    Hsing, Chung-Hsi; Hung, Shih-Kai; Chen, Yeong-Chang; Wei, Tsui-Shan; Sun, Ding-Ping; Wang, Jhi-Joung; Yeh, Ching-Hua

    2015-01-01

    Excessive production of cytokines by microglia may cause cognitive dysfunction and long-lasting behavioral changes. Activating the peripheral innate immune system stimulates cytokine secretion in the central nervous system, which modulates cognitive function. Histone deacetylases (HDACs) modulate cytokine synthesis and release. Trichostatin A (TSA), an HDAC inhibitor, is documented to be anti-inflammatory and neuroprotective. We investigated whether TSA reduces lipopolysaccharide- (LPS-) induced neuroinflammation and cognitive dysfunction. ICR mice were first intraperitoneally (i.p.) injected with vehicle or TSA (0.3?mg/kg). One hour later, they were injected (i.p.) with saline or Escherichia coli LPS (1?mg/kg). We analyzed the food and water intake, body weight loss, and sucrose preference of the injected mice and then determined the microglia activation and inflammatory cytokine expression in the brains of LPS-treated mice and LPS-treated BV-2 microglial cells. In the TSA-pretreated mice, microglial activation was lower, anhedonia did not occur, and LPS-induced cognitive dysfunction (anorexia, weight loss, and social withdrawal) was attenuated. Moreover, mRNA expression of HDAC2, HDAC5, indoleamine 2,3-dioxygenase (IDO), TNF-?, MCP-1, and IL-1? in the brain of LPS-challenged mice and in the LPS-treated BV-2 microglial cells was lower. TSA diminished LPS-induced inflammatory responses in the mouse brain and modulated the cytokine-associated changes in cognitive function, which might be specifically related to reducing HDAC2 and HDAC5 expression. PMID:26273133

  3. MLN4924 induces Noxa upregulation in acute myelogenous leukemia and synergizes with Bcl-2 inhibitors.

    PubMed

    Knorr, K L B; Schneider, P A; Meng, X W; Dai, H; Smith, B D; Hess, A D; Karp, J E; Kaufmann, S H

    2015-12-01

    MLN4924 (pevonedistat), an inhibitor of the Nedd8 activating enzyme (NAE), has exhibited promising clinical activity in acute myelogenous leukemia (AML). Here we demonstrate that MLN4924 induces apoptosis in AML cell lines and clinical samples via a mechanism distinct from those observed in other malignancies. Inactivation of E3 cullin ring ligases (CRLs) through NAE inhibition causes accumulation of the CRL substrate c-Myc, which transactivates the PMAIP1 gene encoding Noxa, leading to increased Noxa protein, Bax and Bak activation, and subsequent apoptotic changes. Importantly, c-Myc knockdown diminishes Noxa induction; and Noxa siRNA diminishes MLN4924-induced killing. Because Noxa also neutralizes Mcl-1, an anti-apoptotic Bcl-2 paralog often upregulated in resistant AML, further experiments have examined the effect of combining MLN4924 with BH3 mimetics that target other anti-apoptotic proteins. In combination with ABT-199 or ABT-263 (navitoclax), MLN4924 exerts a synergistic cytotoxic effect. Collectively, these results provide new insight into MLN4924-induced engagement of the apoptotic machinery that could help guide further exploration of MLN4924 for AML. PMID:26045051

  4. Amplification of CRKL induces transformation and EGFR inhibitor resistance in human non small cell lung cancers

    PubMed Central

    Cheung, Hiu Wing; Du, Jinyan; Boehm, Jesse S.; He, Frank; Weir, Barbara A.; Wang, Xiaoxing; Butaney, Mohit; Sequist, Lecia V.; Luo, Biao; Engelman, Jeffrey A.; Root, David E.; Meyerson, Matthew; Golub, Todd R.; Jänne, Pasi A.; Hahn, William C.

    2011-01-01

    We previously identified a region of recurrent amplification on chromosome 22q11.21 in a subset of primary lung adenocarcinomas. Here we show that CRKL, encoding for an adaptor protein, is amplified and overexpressed in non-small cell lung cancer (NSCLC) cells that harbor 22q11.21 amplifications. Overexpression of CRKL in immortalized human airway epithelial cells promoted anchorage independent growth and tumorigenicity. Oncogenic CRKL activates SOS1-RAS-RAF-ERK and SRC-C3G-RAP1 pathways. Suppression of CRKL in NSCLC cells that harbor CRKL amplifications induced cell death. Overexpression of CRKL in EGFR mutant cells induces resistance to gefitinib by activating ERK and AKT signaling. We identified CRKL amplification in an EGFR inhibitor treated lung adenocarcinoma that was not present prior to treatment. These observations show that CRKL overexpression induces cell transformation, credential CRKL as a therapeutic target for a subset of NSCLC that harbor CRKL amplifications and implicate CRKL as an additional mechanism of resistance to EGFR-directed therapy. PMID:22586683

  5. Farnesyl transferase inhibitors induce neuroprotection by inhibiting Ha-Ras signalling pathway.

    PubMed

    Ruocco, Antonio; Santillo, Mariarosaria; Cicale, Maria; Ser, Rosalba; Cuda, Giovanni; Anrather, Josef; Iadecola, Costantino; Postiglione, Alfredo; Avvedimento, Enrico V; Patern, Roberto

    2007-12-01

    In previous studies we found that the GTPase p21 Harvey-Ras (Ha-Ras) stimulates the production of reactive oxygen species and induces apoptosis by oxidative stress; this effect was reversed by farnesyl transferase inhibitors (FTIs). In this study we investigated whether FTIs reduce rat brain damage induced by an excitotoxic stimulus, and the signalling pathway(s) underlying the neuroprotection by FTIs. In brain tissue, protein levels of Ha-Ras and farnesylation inhibition were assayed by Western blot, and superoxide production was measured by hydroethidine. The excitotoxic lesion was induced by intrastriatal injection of N-methyl-d-aspartate (NMDA). The survival of mouse neuronal cortical cells was assessed by 3-(4,5 dimethylthialzol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). In brain tissue, NMDA increased the protein levels of Ha-Ras, FTIs caused the accumulation of non-prenylated inactive Ras in the cytosolic fraction, and significantly reduced superoxide production and necrotic volume after excitotoxicity. FTIs increased the viability of mouse neuronal cortical cells following oxidative stress. In conclusion, FTIs inhibited Ha-Ras, decreased oxidative stress and reduced necrotic volume by partly acting on neuronal cells. Thus, Ha-Ras inhibition plays a role in the pathology of neuroprotection, suggesting a potential role of FTIs in the treatment of cerebrovascular diseases. PMID:18005061

  6. Sensitization to UV-induced apoptosis by the histone deacetylase inhibitor trichostatin A (TSA)

    SciTech Connect

    Kim, Myoung Sook; Baek, Jin Hyen; Chakravarty, Devulapalli; Sidransky, David; Carrier, France . E-mail: fcarr001@umaryland.edu

    2005-05-15

    UV-induced apoptosis is a protective mechanism that is primarily caused by DNA damage. Cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts are the main DNA adducts triggered by UV radiation. Because the formation of DNA lesions in the chromatin is modulated by the structure of the nucleosomes, we postulated that modification of chromatin compaction could affect the formation of the lesions and consequently apoptosis. To verify this possibility we treated human colon carcinoma RKO cells with the histone deacetylase inhibitor trichostatin A (TSA) prior to exposure to UV radiation. Our data show that pre-treatment with TSA increased UV killing efficiency by more than threefold. This effect correlated with increased formation of CPDs and consequently apoptosis. On the other hand, TSA treatment after UV exposure rather than before had no more effect than UV radiation alone. This suggests that a primed (opened) chromatin status is required to sensitize the cells. Moreover, TSA sensitization to UV-induced apoptosis is p53 dependent. p53 and acetylation of the core histones may thus contribute to UV-induced apoptosis by modulating the formation of DNA lesions on chromatin.

  7. Effects of cytochrome p450 inhibitors on itraconazole and fluconazole induced cytotoxicity in hepatocytes.

    PubMed

    Somchit, Nhareet; Ngee, Chong Sock; Yaakob, Azhar; Ahmad, Zuraini; Zakaria, Zainul Amiruddin

    2009-01-01

    Itraconazole and fluconazole have been reported to induce hepatotoxicity in patients. The present study was designed to investigate the role of cytochrome P450 inhibitors, SKF 525A, and curcumin pretreatment on the cytotoxicity of antifungal drugs fluconazole and itraconazole. For 3 consecutive days, female rats were administered daily SKF 525A or curcumin (5 and 25 mg/kg). Control rats received an equivalent amount of dosed vehicle. The animals were anaesthetized 24 hours after receiving the last dose for liver perfusion. Hepatocytes were then exposed to various concentrations of antifungal drugs. In vitro incubation of hepatocytes with itraconazole revealed significantly lower viability when compared to fluconazole as assessed by lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase activities. The cytotoxicity of itraconazole was enhanced when incubated with hepatocytes pretreated with SKF 525A. SKF 525A had no effects on the cytotoxicity of fluconazole. Curcumin failed to either increase or decrease the cytotoxicity of both antifungal drugs. ATP levels also showed significant decrease in both itraconazole and fluconazole incubated hepatocytes. However, SKF 525A pretreated hepatocytes had significantly lower ATP levels after itraconazole incubations. Collectively, these results confirm the involvement of cytochrome P450 in the cytoprotection in itraconazole induced hepatocyte toxicity. Differences of the effects of SKF 525A on the cytotoxicity induced by itraconazole and fluconazole may be due to the differences on the metabolism of each antifungal drug in vivo. PMID:20130764

  8. Predictive factor and antihypertensive usage of tyrosine kinase inhibitor-induced hypertension in kidney cancer patients.

    PubMed

    Izumi, Kouji; Itai, Shingo; Takahashi, Yoshiko; Maolake, Aerken; Namiki, Mikio

    2014-07-01

    Hypertension (HT) is the common adverse event associated with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKI). The present study was performed to identify the predictive factors of TKI-induced HT and to determine the classes of antihypertensive agents (AHTA) that demonstrate optimal efficacy against this type of HT. The charts of 50 cases of patients that had received VEGFR-TKI treatment were retrospectively examined. The association between patient background and TKI-induced HT, and the effect of administering AHTA were analyzed. High systolic blood pressure at baseline was identified to be a predictive factor for HT. In addition, there was no difference observed between calcium channel blockers (CCBs) and angiotensin receptor II blockers (ARBs) as first-line AHTA for the control of HT. The findings of the present study may aid with predicting the onset of TKI-induced HT, as well as for its management via the primary use of either CCBs or ARBs. PMID:24959266

  9. Expression of the Salmonella Spp. Virulence Factor SifA in Yeast Alters Rho1 Activity on Peroxisomes

    PubMed Central

    Vinh, Dani B. N.; Ko, Dennis C.; Rachubinski, Richard A.; Aitchison, John D.

    2010-01-01

    The Salmonella typhimurium effector protein SifA regulates the assembly and tubulation of the Salmonella phagosome. SifA localizes to the phagosome and interacts with the membrane via its prenylated tail. SifA is a structural homologue of another bacterial effector that acts as a GTP-exchange factor for Rho family GTPases and can bind GDP-RhoA. When coexpressed with a bacterial lipase that is activated by RhoA, SifA can induce tubulation of mammalian endosomes. In an effort to develop a genetic system to study SifA function, we expressed SifA and characterized its activity in yeast. GFP-SifA predominantly localized to yeast peroxisomal membranes. Under peroxisome-inducing conditions, GFP-SifA reduced the number of free peroxisomes and promoted the formation of large peroxisomes with membrane invaginations. GFP-SifA activity depended on the recruitment to peroxisomes of wild-type Rho1p and Pex25p, a receptor for Rho1p. GFP-SifA could also rescue the actin organization defects in pex25Δ and rho1 mutants, suggesting that SifA may recruit and potentiate Rho1p activity. We reexamined the distribution of GFP-SifA in mammalian cells and found the majority colocalizing with LAMP1-positive compartment and not with the peroxisomal marker PMP70. Together, these data suggest that SifA may use a similar mode of action via Rho proteins to alter yeast peroxisomal and mammalian endosomal membranes. Further definition of SifA activity on yeast peroxisomes could provide more insight into its role in regulating host membrane dynamics and small GTPases. PMID:20739463

  10. USP7 inhibitor P22077 inhibits neuroblastoma growth via inducing p53-mediated apoptosis.

    PubMed

    Fan, Y-H; Cheng, J; Vasudevan, S A; Dou, J; Zhang, H; Patel, R H; Ma, I T; Rojas, Y; Zhao, Y; Yu, Y; Zhang, H; Shohet, J M; Nuchtern, J G; Kim, E S; Yang, J

    2013-01-01

    Neuroblastoma (NB) is a common pediatric cancer and contributes to more than 15% of all pediatric cancer-related deaths. Unlike adult tumors, recurrent somatic mutations in NB, such as tumor protein 53 (p53) mutations, occur with relative paucity. In addition, p53 downstream function is intact in NB cells with wild-type p53, suggesting that reactivation of p53 may be a viable therapeutic strategy for NB treatment. Herein, we report that the ubiquitin-specific protease 7 (USP7) inhibitor, P22077, potently induces apoptosis in NB cells with an intact USP7-HDM2-p53 axis but not in NB cells with mutant p53 or without human homolog of MDM2 (HDM2) expression. In this study, we found that P22077 stabilized p53 by inducing HDM2 protein degradation in NB cells. P22077 also significantly augmented the cytotoxic effects of doxorubicin (Dox) and etoposide (VP-16) in NB cells with an intact USP7-HDM2-p53 axis. Moreover, P22077 was found to be able to sensitize chemoresistant LA-N-6 NB cells to chemotherapy. In an in vivo orthotopic NB mouse model, P22077 significantly inhibited the xenograft growth of three NB cell lines. Database analysis of NB patients shows that high expression of USP7 significantly predicts poor outcomes. Together, our data strongly suggest that targeting USP7 is a novel concept in the treatment of NB. USP7-specific inhibitors like P22077 may serve not only as a stand-alone therapy but also as an effective adjunct to current chemotherapeutic regimens for treating NB with an intact USP7-HDM2-p53 axis. PMID:24136231

  11. Mitigation and Treatment of Radiation-Induced Thoracic Injury With a Cyclooxygenase-2 Inhibitor, Celecoxib

    SciTech Connect

    Hunter, Nancy R.; Valdecanas, David; Liao Zhongxing; Milas, Luka; Thames, Howard D.; Mason, Kathy A.

    2013-02-01

    Purpose: To test whether a cyclooxygenase-2 inhibitor (celecoxib) could reduce mortality resulting from radiation-induced pneumonitis. Methods and Materials: Celecoxib was given to mice twice daily for 40 consecutive days starting on the day of local thoracic irradiation (LTI) or 40 or 80 days later. C3Hf/KamLaw mice were observed for morbidity, and time to death was determined. Results were analyzed using the Cox proportional hazards model. Results: Timing of celecoxib relative to LTI determined efficacy. A significant reduction in time to death was achieved only when celecoxib was started 80 days after LTI, corresponding to the time when pneumonitis is expressed. For these mice the reduction in mortality was quantified as a hazard ratio for mortality of treated vs untreated of 0.36 (95% confidence interval [CI] 0.24-0.53), thus significantly less than 1.0. Correspondingly, the median lethal dose for treated mice (12.9 Gy; 95% CI 12.55-13.25 Gy) was significantly (P=.026) higher than for untreated mice (12.4 Gy; 95% CI 12.2-12.65 Gy). Conclusions: Celecoxib significantly reduced lung toxicity when administered months after LTI when the deleterious effects of radiation were expressed. The schedule-dependent reduction in fatal pneumonitis suggests that celecoxib could be clinically useful by reintroduction of treatment months after completion of radiation therapy. These findings may be important for designing clinical trials using cyclooxygenase-2 inhibitors to treat radiation-induced lung toxicity as a complement to concurrent radiation therapy of lung cancers.

  12. Electrophilic Peroxisome ProliferatorActivated Receptor-? Ligands Have Potent Antifibrotic Effects in Human Lung Fibroblasts

    PubMed Central

    Ferguson, Heather E.; Kulkarni, Ajit; Lehmann, Geniece M.; Garcia-Bates, Tatiana M.; Thatcher, Thomas H.; Huxlin, Krystel R.; Phipps, Richard P.; Sime, Patricia J.

    2009-01-01

    Pulmonary fibrosis is a progressive scarring disease with no effective treatment. Transforming growth factor (TGF)-? is up-regulated in fibrotic diseases, where it stimulates differentiation of fibroblasts to myofibroblasts and production of excess extracellular matrix. Peroxisome proliferatoractivated receptor (PPAR) ? is a transcription factor that regulates adipogenesis, insulin sensitization, and inflammation. We report here that a novel PPAR? ligand, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), is a potent inhibitor of TGF-?stimulated differentiation of human lung fibroblasts to myofibroblasts, and suppresses up-regulation of ?smooth muscle actin, fibronectin, collagen, and the novel myofibroblast marker, calponin. The inhibitory concentration causing a 50% decrease in aSMA for CDDO was 20-fold lower than the endogenous PPAR? ligand, 15-deoxy-?12,14-prostaglandin J2 (15 d-PGJ2), and 400-fold lower than the synthetic ligand, rosiglitazone. Pharmacologic and genetic approaches were used to demonstrate that CDDO mediates its activity via a PPAR?-independent pathway. CDDO and 15 d-PGJ2 contain an ?/? unsaturated ketone, which acts as an electrophilic center that can form covalent bonds with cellular proteins. Prostaglandin A1 and diphenyl diselenide, both strong electrophiles, also inhibit myofibroblast differentiation, but a structural analog of 15 d-PGJ2 lacking the electrophilic center is much less potent. CDDO does not alter TGF-?induced Smad or AP-1 signaling, but does inhibit acetylation of CREB binding protein/p300, a critical coactivator in the transcriptional regulation of TGF-?responsive genes. Overall, these data indicate that certain PPAR? ligands, and other small molecules with electrophilic centers, are potent inhibitors of critical TGF-?mediated profibrogenic activities through pathways independent of PPAR?. As the inhibitory concentration causing a 50% decrease in aSMA for CDDO is 400-fold lower than that in rosiglitazone, the translational potential of CDDO for treatment of fibrotic diseases is high. PMID:19286977

  13. Angiotensin-converting enzyme inhibitor (enalapril maleate) accelerates recovery of mouse skin from UVB-induced wrinkles

    SciTech Connect

    Matsuura-Hachiya, Yuko; Arai, Koji Y.; Ozeki, Rieko; Kikuta, Ayako; Nishiyama, Toshio

    2013-12-06

    Highlights: •Angiotensin converting enzyme (ACE) increases in UVB-irradiated skin. •Administration of an ACE inhibitor improved UVB-induced skin wrinkle. •ACE inhibitor improved UVB-induced epidermal hypertrophy. •ACE inhibitor improved transepidermal water loss in the UVB-irradiated skin. -- Abstract: Angiotensin-converting enzyme (ACE) activity and angiotensin II signaling regulate cell proliferation, differentiation, and tissue remodeling, as well as blood pressure, while in skin, angiotensin II signaling is involved in wound healing, inflammation, and pathological scar formation. Therefore, we hypothesized that angiotensin II is also involved in photoaging of skin. In this study, we examined the effect of enalapril maleate, an ACE inhibitor, on recovery of wrinkled skin of hairless mice exposed to long-term UVB irradiation. Immunohistochemical observation revealed that expression of ACE, angiotensin II, and angiotensin II type 1 (AT1) and type 2 (AT2) receptors in the skin was increased after UVB irradiation (3 times/week at increasing intensities for 8 weeks). Administration of enalapril maleate (5 times/week for 6 weeks, starting 1 week after 10-week irradiation) accelerated recovery from UVB-induced wrinkles, epidermal hyperplasia and epidermal barrier dysfunction, as compared with the vehicle control. Our results indicate that ACE and angiotensin II activity are involved in skin photoaging, and suggest that ACE inhibitor such as enalapril maleate may have potential for improvement of photoaged skin.

  14. Small-molecule inhibitors of USP7 induce apoptosis through oxidative and endoplasmic reticulum stress in cancer cells.

    PubMed

    Lee, Gibok; Oh, Taek-In; Um, Ki Bum; Yoon, Hyeshin; Son, Jaekyoung; Kim, Byeong Mo; Kim, Hong-Il; Kim, Hackyoung; Kim, Young Jun; Lee, Chang-Soo; Lim, Ji-Hong

    2016-01-29

    USP7 is a deubiquitinating enzyme that involves the ubiquitin proteasome system (UPS) to maintain regulation of protein synthesis and degradation. The well-known substrate of USP7 is the Mdm2-p53 complex. In fact, several studies have reported that functional inhibition of USP7 induces cancer cell apoptosis through activation of p53. However, the contribution of oxidative or endoplasmic reticulum (ER) stress, which is commonly induced by inhibition of the UPS for USP7 inhibitor-mediated apoptosis in cancer cells, has not been investigated. In contrast to previous reports, we show that p53 is not critical during USP7 inhibitor-induced apoptosis in several cancer cells. Inhibition of deubiquitinating enzyme activities by USP7 inhibitors causes ER stress by accumulating polyubiquitinated proteins in cancer cells. Furthermore, we demonstrate that USP7 inhibitors increase intracellular reactive oxygen species and mainly cause cancer cell apoptosis. Taken together, our results reveal that oxidative and ER stress, rather than the Mdm2-p53 axis, mainly contributes to USP7 inhibitor-mediated apoptosis in cancer cells. PMID:26768359

  15. Branched-chain amino acid biosynthesis inhibitors: herbicide efficacy is associated with an induced carbon-nitrogen imbalance.

    PubMed

    Zabalza, Ana; Zulet, Amaia; Gil-Monreal, Miriam; Igal, Maria; Royuela, Mercedes

    2013-06-15

    Acetolactate synthase (ALS; EC 4.1.3.18) and ketol-acid reductoisomerase (KARI; EC 1.1.1.86) are two consecutive enzymes in the biosynthesis of branched-chain amino acids. Several commercial herbicides inhibit ALS as their primary site of action. KARI has also attracted attention as a potential target for herbicides. Although potent and selective inhibitors of KARI have been discovered, these inhibitors display less herbicidal activity than ALS-inhibiting herbicides. To obtain a better understanding of these findings, we have compared the physiological effects induced in pea plants after KARI or ALS inhibition. Although, both types of inhibitors induce growth arrest and photosynthesis inhibition, plant death occurs more rapidly under ALS inhibition than KARI inhibition. Carbohydrates accumulated in the leaves and roots following treatments with both inhibitors. The carbohydrate accumulation in the leaves occurred as a consequence of a decrease in sink strength. In contrast, the free amino acid content was only affected through ALS inhibition. These results indicate that although KARI and ALS inhibition block the same biosynthetic pathway and exert common effects on carbon metabolism, nitrogen metabolism is more affected via ALS than KARI inhibition. Thus, metabolic alterations in nitrogen metabolism induced through ALS inhibitors might contribute to the increased efficacy of these chemicals as herbicides. PMID:23394788

  16. The Proteome of Human Liver Peroxisomes: Identification of Five New Peroxisomal Constituents by a Label-Free Quantitative Proteomics Survey

    PubMed Central

    Ofman, Rob; Bunse, Christian; Pawlas, Magdalena; Hayen, Heiko; Eisenacher, Martin; Stephan, Christian; Meyer, Helmut E.; Waterham, Hans R.; Erdmann, Ralf; Wanders, Ronald J.; Warscheid, Bettina

    2013-01-01

    The peroxisome is a key organelle of low abundance that fulfils various functions essential for human cell metabolism. Severe genetic diseases in humans are caused by defects in peroxisome biogenesis or deficiencies in the function of single peroxisomal proteins. To improve our knowledge of this important cellular structure, we studied for the first time human liver peroxisomes by quantitative proteomics. Peroxisomes were isolated by differential and Nycodenz density gradient centrifugation. A label-free quantitative study of 314 proteins across the density gradient was accomplished using high resolution mass spectrometry. By pairing statistical data evaluation, cDNA cloning and in vivo colocalization studies, we report the association of five new proteins with human liver peroxisomes. Among these, isochorismatase domain containing 1 protein points to the existence of a new metabolic pathway and hydroxysteroid dehydrogenase like 2 protein is likely involved in the transport or ?-oxidation of fatty acids in human peroxisomes. The detection of alcohol dehydrogenase 1A suggests the presence of an alternative alcohol-oxidizing system in hepatic peroxisomes. In addition, lactate dehydrogenase A and malate dehydrogenase 1 partially associate with human liver peroxisomes and enzyme activity profiles support the idea that NAD+ becomes regenerated during fatty acid ?-oxidation by alternative shuttling processes in human peroxisomes involving lactate dehydrogenase and/or malate dehydrogenase. Taken together, our data represent a valuable resource for future studies of peroxisome biochemistry that will advance research of human peroxisomes in health and disease. PMID:23460848

  17. ABCD1 deletion-induced mitochondrial dysfunction is corrected by SAHA: implication for adrenoleukodystrophy.

    PubMed

    Baarine, Mauhamad; Beeson, Craig; Singh, Avtar; Singh, Inderjit

    2015-05-01

    X-linked Adrenoleukodystrophy (X-ALD), an inherited peroxisomal metabolic neurodegenerative disorder, is caused by mutations/deletions in the ATP-binding cassette transporter (ABCD1) gene encoding peroxisomal ABC transporter adrenoleukodystrophy protein (ALDP). Metabolic dysfunction in X-ALD is characterized by the accumulation of very long chain fatty acids ≥ C22:0) in the tissues and plasma of patients. Here, we investigated the mitochondrial status following deletion of ABCD1 in B12 oligodendrocytes and U87 astrocytes. This study provides evidence that silencing of peroxisomal protein ABCD1 produces structural and functional perturbations in mitochondria. Activities of electron transport chain-related enzymes and of citric acid cycle (TCA cycle) were reduced; mitochondrial redox status was dysregulated and the mitochondrial membrane potential was disrupted following ABCD1 silencing. A greater reduction in ATP levels and citrate synthase activities was observed in oligodendrocytes as compared to astrocytes. Furthermore, most of the mitochondrial perturbations induced by ABCD1 silencing were corrected by treating cells with suberoylanilide hydroxamic acid, an Histone deacetylase inhibitor. These observations indicate a novel relationship between peroxisomes and mitochondria in cellular homeostasis and the importance of intact peroxisomes in relation to mitochondrial integrity and function in the cell types that participate in the pathobiology of X-ALD. These observations suggest suberoylanilide hydroxamic acid as a potential therapy for X-ALD. Schematic description of the effects of loss of peroxisomal ATP-binding cassette transporter D1 (ABCD1) gene on cellular Redox and mitochondrial activities and their correction by suberoylanilide hydroxamic acid (SAHA) treatment. Pathogenomic accumulation of very long chain fatty acids (VLCFA) as a result of loss of ABCD1 leads to dysfunctions of mitochondrial biogenesis and its activities. Treatment with SAHA corrects mitochondrial dysfunctions. These studies describe unique cooperation between mitochondria and peroxisome for cellular activities. PMID:25393703

  18. Selective inhibitors of cyclo-oxygenase-2 (COX-2) induce hypoalgesia in a rat paw model of inflammation

    PubMed Central

    Francischi, J N; Chaves, C T; Moura, A C L; Lima, A S; Rocha, O A; Ferreira-Alves, D L; Bakhle, Y S

    2002-01-01

    It is well-established that inhibitors of cyclo-oxygenase (COX) and hence of prostaglandin (PG) biosynthesis reverse inflammatory hyperalgesia and oedema in both human and animal models of inflammatory pain. Paw oedema and hyperalgesia in rats were induced by injecting carrageenan (250 ?g paw?1) into a hindpaw. Both inflammatory responses were followed for 24 h after the injection, measuring hyperalgesia by decreased pain threshold in the paws and oedema by plethysmography. Three selective inhibitors of cyclo-oxygenase-2 (COX-2), celecoxib, rofecoxib and SC 236, given systemically in a range of doses, before the inflammatory stimulus, abolished carrageenan-induced hyperalgesia with little reduction of oedema. These inhibitors also induced hypoalgesia, increasing nociceptive thresholds in the inflamed paw above normal, non-inflamed levels. This hypoalgesia was lost at the higher doses of the selective inhibitors, although hyperalgesia was still prevented. In paws injected with saline only, celecoxib, given at the dose inducing the maximum hypoalgesia after carrageenan, did not alter the nociceptive thresholds. Two non-selective inhibitors of COX-2, indomethacin and piroxicam, abolished hyperalgesia and reduced oedema but did not induce hypoalgesia. Celecoxib given locally into the paw also abolished inflammatory hyperalgesia and induced hypoalgesia without reducing oedema. We conclude that hypoalgesia is expressed only over a critical range of COX-2 inhibition and that concomitant inhibition of COX-1 prevents expression of hypoalgesia, although hyperalgesia is still prevented. Our results suggest a novel anti-nociceptive pathway mediating hypoalgesia, involving COX-2 selectively and having a clear peripheral component. This peripheral component can be further explored for therapeutic purposes. PMID:12411415

  19. Relaxin causes selective outward remodeling of brain parenchymal arterioles via activation of peroxisome proliferator-activated receptor-γ

    PubMed Central

    Chan, Siu-Lung; Cipolla, Marilyn J.

    2011-01-01

    Brain parenchymal arterioles (PAs), but not pial arteries, undergo hypotrophic outward remodeling during pregnancy that involves peroxisome proliferator-activated receptor-γ (PPARγ) activation. Relaxin, a peptide hormone produced during pregnancy, is involved in systemic and renal artery remodeling and activates PPARγ in vitro. Thus, we hypothesized that relaxin is involved in the selective outward remodeling of PAs through a PPARγ-dependent mechanism. Nonpregnant rats were treated with relaxin (4 μg/h, osmotic minipump), relaxin plus PPARγ inhibitor GW9662 (10 mg/kg/d), or vehicle for 10 d. Vascular function and structure were compared in isolated and pressurized middle cerebral arteries (MCAs) and PAs taken from the same animals. Relaxin treatment increased serum relaxin to the level of pregnancy (54 ng/ml) and increased passive wall thickness (hypertrophy; 70±5 vs. 54±4 μm in vehicle; P<0.05) and inner diameter (outward remodeling; 10.6±0.5 vs. 8.0±0.6 μm in vehicle; P<0.05) in PAs, but not in MCAs. This hypertrophic outward remodeling was prevented by GW9662 that had diameters (57±3 μm) and wall thickness (8.6±1.0 μm) similar to vehicle. GW9662 also prevented relaxin-induced changes in PPARγ target gene expression. These results suggest that relaxin produced during pregnancy may be partly responsible for selective remodeling of PAs during pregnancy through a mechanism involving PPARγ.—Chan, S.-L., Cipolla, M. J. Relaxin causes selective outward remodeling of brain parenchymal arterioles via activation of peroxisome proliferator-activated receptor-γ. PMID:21602449

  20. Tyrosine kinase inhibitor-induced differentiation of K-562 cells: alterations of cell cycle and cell surface phenotype.

    PubMed

    Hunkov, L; Sedlk, J; Klobusick, M; Duraj, J; Chorvth, B

    1994-06-15

    Protein tyrosine kinase (PTK) inhibitor herbimycin A inhibited proliferation, induced accumulation of cells in the G0/G1 phase of the cell cycle and a marked increae of hemoglobin-producing human leukemic K-562 cells in vitro. The isoflavonoid PTK- and topoisomerase II inhibitor genistein produced a similar effect with the accumulation of cells in the G2/M phase of cell cycle. Genistein potentiated the effect of herbimycin A on the cell cycle (i.e. decreased the proportion of S-phase cells) and induced an increased proportion of hemoglobin-producing cells. Genistein, but not herbimycin A induced a marked increase in cell surface expression of CD15 (LewisX) antigen. Both of these agents down-regulated CD45 (leukocyte common antigen) and monocyte-associated CD14 antigen on K-562 cells. Neither genistein nor herbimycin A induced increased cell surface expression of glycophorin. PMID:8019992

  1. MDM2 Inhibitor, Nutlin 3a, Induces p53 Dependent Autophagy in Acute Leukemia by AMP Kinase Activation

    PubMed Central

    Borthakur, Gautam; Duvvuri, Seshagiri; Ruvolo, Vivian; Tripathi, Durga Nand; Piya, Sujan; Burks, Jared; Jacamo, Rodrigo; Kojima, Kensuke; Ruvolo, Peter; Fueyo-Margareto, Juan; Konopleva, Marina; Andreeff, Michael

    2015-01-01

    MDM2 (mouse double minute 2) inhibitors that activate p53 and induce apoptosis in a non-genotoxic manner are in clinical development for treatment of leukemias. P53 can modulate other programmed cell death pathways including autophagy both transcriptionally and non-transcriptionally. We investigated autophagy induction in acute leukemia by Nutlin 3a, a first-in-class MDM2 inhibitor. Nutlin 3a induced autophagy in a p53 dependent manner and transcriptional activation of AMP kinase (AMPK) is critical, as this effect is abrogated in AMPK -/- mouse embryonic fibroblasts. Nutlin 3a induced autophagy appears to be pro-apoptotic as pharmacological (bafilomycin) or genetic inhibition (BECLIN1 knockdown) of autophagy impairs apoptosis induced by Nutlin 3a. PMID:26440941

  2. The cytosolic and membrane components required for peroxisomal protein import.

    PubMed

    Terlecky, S R; Nuttley, W M; Subramani, S

    1996-12-15

    Peroxisomes are vital intracellular organelles which house enzymes involved in a variety of metabolic pathways. The large number of human disorders associated with flawed peroxisome biogenesis emphasizes the importance of protein targeting to, and translocation across, the peroxisomal membrane. This brief review will summarize some of the emerging themes of peroxisomal protein import, specifically addressing the targeting signals possessed by constituent proteins, as well as the cytosolic, membrane and luminal components of the import machinery. Although a detailed understanding of the molecular mechanisms of peroxisomal protein import is not yet available, remarkable progress has been made in the field in recent years. An overview of these advances will be presented. PMID:8988245

  3. Mutation of the Arabidopsis LON2 peroxisomal protease enhances pexophagy

    PubMed Central

    Bartel, Bonnie; Farmer, Lisa M; Rinaldi, Mauro A; Young, Pierce G; Danan, Charles H; Burkhart, Sarah E

    2014-01-01

    Peroxisomes are critical organelles housing various, often oxidative, reactions. Pexophagy, the process by which peroxisomes are selectively targeted for destruction via autophagy, is characterized in yeast and mammals but had not been reported in plants. In this article, we describe how the peroxisome-related aberrations of a mutant defective in the LON2 peroxisomal protease are suppressed when autophagy is prevented by mutating any of several key autophagy-related (ATG) genes. Our results reveal that plant peroxisomes can be degraded by selective autophagy and suggest that pexophagy is accelerated when the LON2 protease is disabled. PMID:24413187

  4. Clinical significance of plasminogen activator inhibitor activity in patients with exercise-induced ischemia

    SciTech Connect

    Sakata, K.; Kurata, C.; Taguchi, T.; Suzuki, S.; Kobayashi, A.; Yamazaki, N.; Rydzewski, A.; Takada, Y.; Takada, A. )

    1990-10-01

    To assess the fibrinolytic system in patients with exercise-induced ischemia and its relation to ischemia and severity of coronary artery disease (CAD), 47 patients with CAD confirmed by results of coronary angiography underwent symptom-limited multistage exercise thallium-201 emission computed tomography. All patients with CAD had exercise-induced ischemia as assessed from thallium-201 images. Pre- and peak exercise blood samples from each patient and preexercise blood samples from control subjects were assayed for several fibrinolytic components and were also assayed for plasma adrenaline. The extent of ischemia was defined as delta visual uptake score (total visual uptake score in delayed images minus total visual uptake score in initial images) and the severity of CAD as the number of diseased vessels. In the basal condition, plasminogen activator inhibitor (PAI) activity was significantly higher in patients with exercise-induced ischemia as compared to control subjects (p less than 0.01), although there were no significant differences in other fibrinolytic variables between the two groups. Moreover, PAI activity in the basal condition displayed a significantly positive correlation with the extent of ischemia (r = 0.47, p less than 0.01). Patients with exercise-induced ischemia were divided into two groups (24 with single-vessel disease and 23 with multivessel disease). There were no significant differences in coronary risk factors, hemodynamics, or plasma adrenaline levels during exercise between single-vessel and multivessel disease except that delta visual uptake score was significantly higher in multivessel disease (p less than 0.01).

  5. Catalase degradation in sunflower cotyledons during peroxisome transition from glyoxysomal to leaf peroxisomal function. [Helianthus annuus

    SciTech Connect

    Eising, R.; Gerhardt, B.

    1987-06-01

    First order rate constant for the degradation (degradation constants) of catalase in the cotyledons of sunflower (Helianthus annuus L.) were determined by measuring the loss of catalase containing /sup 14/C-labeled heme. During greening of the cotyledons, a period when peroxisomes change from glyoxysomal to leaf peroxisomal function, the degradation of glyoxysomal catalase is significantly slower than during all other stages of cotyledon development in light or darkness. The degradation constant during the transition stage of peroxisome function amounts to 0.205 day/sup -1/ in contrast to the constants ranging from 0.304 day/sup -1/ to 0.515 day/sup -1/ during the other developmental stages. Density labeling experiments comprising labeling of catalase with /sup 2/H/sub 2/O and its isopycnic centrifugation on CsCl gradients demonstrated that the determinations of the degradation constants were not substantially affected by reutilization of /sup 14/C-labeled compounds for catalase synthesis. The degradation constants for both glyoxysomal catalase and catalase synthesized during the transition of peroxisome function do not differ. This was shown by labeling the catalases with different isotopes and measuring the isotope ratio during the development of the cotyledons. The results are inconsistent with the concept that an accelerated and selective degradation of glyoxysomes underlies the change in peroxisome function. The data suggest that catalase degradation is at least partially due to an individual turnover of catalase and does not only result from a turnover of the whole peroxisomes.

  6. Protein phosphatase 2A holoenzyme is targeted to peroxisomes by piggybacking and positively affects peroxisomal ?-oxidation.

    PubMed

    Kataya, Amr R A; Heidari, Behzad; Hagen, Lars; Kommedal, Roald; Slupphaug, Geir; Lillo, Cathrine

    2015-02-01

    The eukaryotic, highly conserved serine (Ser)/threonine-specific protein phosphatase 2A (PP2A) functions as a heterotrimeric complex composed of a catalytic (C), scaffolding (A), and regulatory (B) subunit. In Arabidopsis (Arabidopsis thaliana), five, three, and 17 genes encode different C, A, and B subunits, respectively. We previously found that a B subunit, B'?, localized to peroxisomes due to its C-terminal targeting signal Ser-Ser-leucine. This work shows that PP2A C2, C5, andA2 subunits interact and colocalize with B'? in peroxisomes. C and A subunits lack peroxisomal targeting signals, and their peroxisomal import depends on B'? and appears to occur by piggybacking transport. B'? knockout mutants were impaired in peroxisomal ?-oxidation as shown by developmental arrest of seedlings germinated without sucrose, accumulation of eicosenoic acid, and resistance to protoauxins indole-butyric acid and 2,4-dichlorophenoxybutyric acid. All of these observations strongly substantiate that a full PP2A complex is present in peroxisomes and positively affects ?-oxidation of fatty acids and protoauxins. PMID:25489022

  7. Effect of NADPH-oxidase inhibitors in the experimental model of zymosan-induced shock in mice.

    PubMed

    Impellizzeri, Daniela; Mazzon, Emanuela; Di Paola, Rosanna; Paterniti, Irene; Bramanti, Placido; Cuzzocrea, Salvatore

    2011-07-01

    The aim of this study was to investigate the effects of NADPH-oxidase inhibitors, in a mouse model of zymosan. Zymosan-induced shock was induced in mice by administration of zymosan (500 mg/kg, i.p.). The pharmacological treatment was the administration of apocynin (5 mg/kg 10% DMSO i.p.) and diphenylene iodonium chloride (DPI) (1 mg/kg i.v.) 1 h and 6 h after zymosan administration. MOF and systemic inflammation in mice was assessed 18 h after administration of zymosan. NADPH-oxidase inhibitors caused a significant reduction of the (1) peritoneal exudate formation, (2) neutrophil infiltration, (3) multiple organ dysfunction syndrome, (4) nitrotyrosine, (5) poly (ADP-ribose) (PAR), (6) cytokine formation, (7) adhesion molecule expression, (8) nuclear factor (NF-?B) expression and (9) apoptosis induced by zymosan. Moreover, NADPH-oxidase inhibitors treatment significantly reduced the systemic toxicity, the loss in body weight and the mortality caused by zymosan. This study has shown that NADPH-oxidase inhibitors attenuate the degree of zymosan-induced non-septic shock in mice. PMID:21623687

  8. Defining the Plant Peroxisomal Proteome: From Arabidopsis to Rice

    PubMed Central

    Kaur, Navneet; Hu, Jianping

    2011-01-01

    Peroxisomes are small subcellular organelles mediating a multitude of processes in plants. Proteomics studies over the last several years have yielded much needed information on the composition of plant peroxisomes. In this review, the status of peroxisome proteomics studies in Arabidopsis and other plant species and the cumulative advances made through these studies are summarized. A reference Arabidopsis peroxisome proteome is generated, and some unique aspects of Arabidopsis peroxisomes that were uncovered through proteomics studies and hint at unanticipated peroxisomal functions are also highlighted. Knowledge gained from Arabidopsis was utilized to compile a tentative list of peroxisome proteins for the model monocot plant, rice. Differences in the peroxisomal proteome between these two model plants were drawn, and novel facets in rice were expounded upon. Finally, we discuss about the current limitations of experimental proteomics in decoding the complete and dynamic makeup of peroxisomes, and complementary and integrated approaches that would be beneficial to defining the peroxisomal metabolic and regulatory roadmaps. The synteny of genomes in the grass family makes rice an ideal model to study peroxisomes in cereal crops, in which these organelles have received much less attention, with the ultimate goal to improve crop yield. PMID:22645559

  9. MET inhibitor PHA-665752 suppresses the hepatocyte growth factor-induced cell proliferation and radioresistance in nasopharyngeal carcinoma cells

    SciTech Connect

    Liu, Tongxin; Li, Qi; Sun, Quanquan; Zhang, Yuqin; Yang, Hua; Wang, Rong; Chen, Longhua; Wang, Wei

    2014-06-20

    Highlights: • We demonstrated that irradiation induced MET overexpression and activation. • The aberrant MET signal mediated by HGF induced proliferation and radioresistance of NPC cells. • MET inhibitor PHA-665752 effectively suppressed HGF induced cell proliferation and radioresistance in NPC cells. • PHA-665752 suppressed the three downstream pathway of HGF/MET signal in a dose-dependent manner. - Abstract: Although ionizing radiation (IR) has provided considerable improvements in nasopharyngeal carcinoma (NPC), in subsets of patients, radioresistance is still a major problem in the treatment. In this study, we demonstrated that irradiation induced MET overexpression and activation, and the aberrant MET signal mediated by hepatocyte growth factor (HGF) induced radioresistance. We also found that MET inhibitor PHA-665752 effectively suppressed HGF induced cell proliferation and radioresistance in NPC cells. Further investigation indicated that PHA-665752 suppressed the phosphorylation of the Akt, ERK1/2, and STAT3 proteins in a dose-dependent manner. Our data indicated that the combination of IR with a MET inhibitor, such as PHA-665752, might be a promising therapeutic strategy for NPC.

  10. RANKL Inhibitors Induce Osteonecrosis of the Jaw in Mice With Periapical Disease

    PubMed Central

    Aghaloo, Tara L; Cheong, Simon; Bezouglaia, Olga; Kostenuik, Paul; Atti, Elisa; Dry, Sarah M; Pirih, Flavia Q; Tetradis, Sotirios

    2015-01-01

    Antiresorptive medications are essential in treating diseases of pathologic osteoclastic bone resorption, including bone cancer and osteoporosis. Bisphosphonates (BPs) are the most commonly used antiresorptives in clinical practice. Although inhibition of bone resorption is important in regulating unwanted malignant and metabolic osteolysis, BP treatment is associated with potential side effects, including osteonecrosis of the jaws (ONJ). Recently, non-BP antiresorptive medications targeting osteoclastic function and differentiation, such as denosumab, have entered the clinical arena. Denosumab treatment results in a similar rate of ONJ as BPs. Animal models of ONJ, using high-dose BP treatment in combination with tooth extraction or dental disease, provide valuable tools and insight in exploring ONJ pathophysiology. However, the ability of other antiresorptives to induce ONJ-like lesions in animal models has not been explored. Such studies would be beneficial in providing support for the role of osteoclast inhibition in ONJ pathogenesis versus a direct BP effect on oral tissues. Here, we tested the ability of the receptor activator of NF-kB ligand (RANKL) inhibitors RANK-Fc (composed of the extracellular domain of RANK fused to the fragment crystallizable [Fc] portion of immunoglobulin G [IgG]) and OPG-Fc (composed of the RANKL-binding domains of osteoprotegerin [OPG] linked to the Fc portion of IgG) to induce ONJ in mice in the presence of periapical disease, but in the absence of dental extractions. We demonstrate radiographic evidence of ONJ in RANK-Fctreated and OPG-Fctreated mice, including inhibition of bone loss, increased bone density, lamina dura thickening, and periosteal bone deposition. These findings closely resembled the radiographic appearance of an ONJ patient on denosumab treatment. Histologic examination revealed that RANK-Fc treatment and OPG-Fc treatment resulted in absence of osteoclasts, periosteal bone formation, empty osteocytic lacunae, osteonecrosis, and bone exposure. In conclusion, we have successfully induced ONJ in mice with periapical disease, using potent osteoclast inhibitors other than BPs. Our findings, coupled with ONJ animal models using high-dose BPs, suggest that osteoclast inhibition is pivotal to the pathogenesis of ONJ. PMID:24115073

  11. The Cyclin-Dependent Kinase Inhibitor SCH 727965 (Dinacliclib) Induces the Apoptosis of Osteosarcoma Cells

    PubMed Central

    Fu, Wei; Ma, Le; Chu, Baoky; Wang, Xue; Bui, Marilyn M.; Gemmer, Jennifer; Altiok, Soner; Pledger, W. Jackson

    2015-01-01

    Although rare, osteosarcoma is an aggressive cancer that often metastasizes to the lungs. Toward the goal of developing new treatment options for osteosarcoma, we show that the cyclin-dependent kinase (CDK) inhibitor SCH 727965 (SCH) induces the apoptosis of several osteosarcoma cell lines including those resistant to doxorubicin and dasatinib. Cell lines prepared in our laboratory from patients who had received adjuvant chemotherapy and explants derived from a human osteosarcoma xenograft in mice were also responsive to SCH. Apoptosis occurred at low nanomolar concentrations of SCH, as did CDK inhibition, and was p53-independent. SCH activated the mitochondrial pathway of apoptosis as evidenced by caspase-9 cleavage and accumulation of cytoplasmic cytochrome c. Amounts of the apoptotic proteins Bax and Bim increased in mitochondria, whereas amounts of the antiapoptotic proteins Mcl-1 and Bcl-xL declined. Osteosarcoma cells apoptosed when codepleted of CDK1 and CDK2 but not when depleted of other CDK combinations. We suggest that SCH triggers the apoptosis of osteosarcoma cells by inactivating CDK1 and CDK2 and that SCH may be useful for treatment of drug-resistant osteosarcomas. SCH also induced the apoptosis of other sarcoma types but not of normal quiescent osteoblasts or fibroblasts. PMID:21490307

  12. Contact lens-induced edema in vitro--amelioration by lactate dehydrogenase inhibitors.

    PubMed

    Rohde, M D; Huff, J W

    1986-10-01

    Isolated rabbit corneas bathed in Krebs-bicarbonate Ringer solution were observed for thickness changes after a 90 minute equilibration period. Control corneas swelled an average of 0.5 micron/hr, and placement of a polymethylmechacrylate (PMMA) contact lens on the epithelial surface caused the corneas to swell 24.5 microns/hr, an effect similar to 0.5 mM epithelial cyanide exposure. The pronounced swelling induced by PMMA lens placement was much less however, in the epithelial presence of 3.2 mM sodium oxalate (3.22 microns/hr) or 3.2 mM sodium oxamate (5.38 microns/hr). An equiosmotic excess of 4.8 mM NaCl was least active (15.89 microns/hr). On normal isolated corneas (without contact lenses), the Ringer containing an excess of 4.8 mM NaCl significantly deswelled the corneas (-13.44 microns/hr), which contrasted with oxalate and oxamate containing Ringer solutions (1.17 and 1.33 micron/hr respectively). The present study supports the notion that contact lens-induced edema results from stromal lactate accumulation, and suggests a potential alternative to osmotic therapy for its amelioration. These LDH inhibitors, in the concentrations used, have no acute osmotic or toxic effect on normal corneas in vitro. PMID:3769523

  13. CT-2576, an inhibitor of phospholipid signaling, suppresses constitutive and induced expression of human immunodeficiency virus.

    PubMed Central

    Leung, D W; Peterson, P K; Weeks, R; Gekker, G; Chao, C C; Kaplan, A H; Balantac, N; Tompkins, C; Underiner, G E; Bursten, S

    1995-01-01

    Viruses such as human immunodeficiency virus (HIV) require cellular activation for expression. Cellular activation in lymphoid cells is associated with augmented accumulation of certain phosphatidic acid (PA) species derived from the hydrolysis of glycan phosphatidylinositol (GPI). This suggests that activation of a phospholipid pathway may play a role in initiation of viral replication. To test this hypothesis, we examined the effect of tat gene expression on the production of cellular PA species, as the Tat protein is essential for HIV expression and has been implicated in activating the expression of multiple host cellular genes. Expression of tat increased the expression of PA. We then tested whether synthetic inhibitors of PA metabolism would inhibit activation of the HIV long terminal repeat by Tat and tumor necrosis factor alpha (TNF-alpha). CT-2576 suppressed both PA generation induced by Tat and HIV long terminal repeat-directed gene expression in response to Tat or TNF-alpha at a posttranscriptional step. CT-2576 also inhibited constitutive as well as TNF-alpha- and interleukin 6-induced expression of HIV p24 antigen in chronically infected U1 cells and in peripheral blood lymphocytes acutely infected with a clinical isolate of HIV. Pharmacological inhibition of synthesis of selected PA species may therefore provide a therapeutic approach to suppression of HIV replication. Images Fig. 1 Fig. 3 Fig. 5 PMID:7761405

  14. Fatostatin, an SREBP inhibitor, prevented RANKL-induced bone loss by suppression of osteoclast differentiation.

    PubMed

    Inoue, Kazuki; Imai, Yuuki

    2015-11-01

    Osteoclast differentiation is associated with both normal bone homeostasis and pathological bone diseases such as osteoporosis. Several transcription factors can regulate osteoclast differentiation, including c-fos and Nfatc1. Using genome-wide DNase-seq analysis, we found a novel transcription factor, SREBP2, that participates in osteoclast differentiation in vitro. Here, we asked whether SREBP2 actually plays a role in controlling bone metabolism in vivo. To answer this question, RAW264 cells, primary cultured osteoclasts and the mouse RANKL-induced bone loss model were treated with fatostatin, a small molecule inhibitor specific for the activation of SREBP. When cells were treated with fatostatin, osteoclast differentiation was impaired. Similar results were obtained following treatment with siRNA for Srebf2, the gene coding for SREBP2. In vivo, ?CT analyses showed that fatostatin treatment preserved bone mass and structure in the proximal tibial trabecular bone in the mouse RANKL-induced bone loss model. In addition, bone histomorphometric analysis revealed that the protection of bone mass by fatostatin might have been achieved by suppression of RANKL-mediated osteoclast differentiation. These results indicated that the novel transcription factor SREBP2 physiologically functions in osteoclast differentiation in vivo and might be a possible therapeutic target for bone diseases. PMID:26319416

  15. Novel Epidermal Growth Factor Receptor Inhibitor Attenuates Angiotensin II-Induced Kidney Fibrosis.

    PubMed

    Qian, Yuanyuan; Peng, Kesong; Qiu, Chenyu; Skibba, Melissa; Huang, Yi; Xu, Zheng; Zhang, Yali; Hu, Jie; Liang, Dandan; Zou, Chunpeng; Wang, Yi; Liang, Guang

    2016-01-01

    Chronic activation of renin-angiotensin system (RAS) greatly contributes to renal fibrosis and accelerates the progression of chronic kidney disease; however, the underlying molecular mechanism is poorly understood. Angiotensin II (Ang II), the central component of RAS, is a key regulator of renal fibrogenic destruction. Here we show that epidermal growth factor receptor (EGFR) plays an important role in Ang II-induced renal fibrosis. Inhibition of EGFR activation by novel small molecules or by short hairpin RNA knockdown in Ang II-treated SV40 mesangial cells in vitro suppresses protein kinase B and extracellular signal-related kinase signaling pathways and transforming growth factor-β/Sma- and Mad-related protein activation, and abolishes the accumulation of fibrotic markers such as connective tissue growth factor, collagen IV. The transactivation of EGFR by Ang II in SV40 cells depends on the phosphorylation of proto-oncogene tyrosine-protein kinase Src (c-Src) kinase. Further validation in vivo demonstrates that EGFR small molecule inhibitor successfully attenuates renal fibrosis and kidney dysfunction in a mouse model induced by Ang II infusion. These findings indicate a crucial role of EGFR in Ang II-dependent renal deterioration, and reveal EGFR inhibition as a new therapeutic strategy for preventing progression of chronic renal diseases. PMID:26514795

  16. Design and synthesis of novel small-molecule inhibitors of the hypoxia inducible factor pathway.

    PubMed

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

    2011-12-22

    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 ability of HIF-1?/HIF-1? to interact with cofactors p300/CBP to form an active transcriptional complex. PMID:22032632

  17. Inhibitors of nitric oxide synthase enhance rat ileum contractions induced by ricinoleic acid in vitro.

    PubMed

    Izzo, A A; Mascolo, N; Viola, P; Capasso, F

    1993-10-12

    The effects of NG-nitro-L-arginine methyl ester (L-NAME) and NG-monomethyl-L-arginine (L-NMMA), inhibitors of nitric oxide (NO) synthase, were studied on ricinoleic acid-evoked contractions in rat isolated ileum. Ricinoleic acid (10(-5) to 10(-4) M) caused a concentration-dependent contraction. Addition of L-NAME (30-300 microM) or L-NMMA (30-300 microM) to the Tyrode's solution increased in a concentration-dependent fashion the amplitude of the ricinoleic acid-evoked responses. L-Arginine (900 microM), a natural substrate of NO synthase, but not D-arginine (900 microM), counteracted the effect of L-NAME (300 microM). The potentiating effect of L-NAME was also prevented by sodium nitroprusside (0.1-1 microM), a generator of NO. These results provide evidence that endogenous NO may modulate the contraction of rat ileum induced by ricinoleic acid. As the contraction induced by ricinoleic acid is not blocked by tetrodotoxin (0.6 and 6.0 microM) the contractile effect of ricinoleic acid results mainly from a direct action on the smooth muscle. PMID:7504631

  18. Inhibitors of nitric oxide synthase enhance rat ileum contractions induced by ricinoleic acid in vitro.

    TOXLINE Toxicology Bibliographic Information

    Izzo AA; Mascolo N; Viola P; Capasso F

    1993-10-12

    The effects of NG-nitro-L-arginine methyl ester (L-NAME) and NG-monomethyl-L-arginine (L-NMMA), inhibitors of nitric oxide (NO) synthase, were studied on ricinoleic acid-evoked contractions in rat isolated ileum. Ricinoleic acid (10(-5) to 10(-4) M) caused a concentration-dependent contraction. Addition of L-NAME (30-300 microM) or L-NMMA (30-300 microM) to the Tyrode's solution increased in a concentration-dependent fashion the amplitude of the ricinoleic acid-evoked responses. L-Arginine (900 microM), a natural substrate of NO synthase, but not D-arginine (900 microM), counteracted the effect of L-NAME (300 microM). The potentiating effect of L-NAME was also prevented by sodium nitroprusside (0.1-1 microM), a generator of NO. These results provide evidence that endogenous NO may modulate the contraction of rat ileum induced by ricinoleic acid. As the contraction induced by ricinoleic acid is not blocked by tetrodotoxin (0.6 and 6.0 microM) the contractile effect of ricinoleic acid results mainly from a direct action on the smooth muscle.

  19. Beneficial effects of nilotinib, tyrosine kinase inhibitor on cyclosporine-A induced renal damage in rats.

    PubMed

    Nader, Manar A; Attia, Ghalia M

    2016-04-01

    Nilotinib is a known tyrosine kinase inhibitor that has been approved for treatment of leukemia. The possible protective effect of nilotinib on cyclosporine A-induced nephropathy was investigated in this study and the possible underlying mechanism was explored. Nilotinib (25mg/kg, orally) and cyclosporine A (15mg/kg/day, subcutaneous) were given to male SD rats for 28days. Cyclosporine A alone was found to significantly increase serum creatinine, blood urea nitrogen, lactate dehydrogenase, urinary micrototal protein, renal thiobarbituric acid reactive substance, Bax, cytosol cytochrome c release and nuclear factor kappa B activation. Moreover, cyclosporine A significantly reduced serum albumin, creatinine clearance, urinary total antioxidant, superoxide dismutase, glutathione and Bcl2 protein levels. Pathological results showed that in the model group; there was an obvious shrinkage and congestion of the glomeruli and widening of urinary spaces of renal corpuscles, in addition to marked renal tubular injury and fibrosis, while in the group pretreated with nilotinib all measured serum, renal and pathological changes were significantly reduced. This protective effect of nilotinib is linked to the enhanced antioxidant status and reduced inflammation and apoptosis induced by cyclosporine A. PMID:26844915

  20. The NADPH oxidase inhibitor apocynin induces nitric oxide synthesis via oxidative stress

    SciTech Connect

    Riganti, Chiara

    2008-05-01

    We have recently shown that apocynin elicits an oxidative stress in N11 mouse glial cells and other cell types. Here we report that apocynin increased the accumulation of nitrite, the stable derivative of nitric oxide (NO), in the extracellular medium of N11 cell cultures, and the NO synthase (NOS) activity in cell lysates. The increased synthesis of NO was associated with increased expression of inducible NOS (iNOS) mRNA, increased nuclear translocation of the redox-sensitive transcription factor NF-{kappa}B and decreased intracellular level of its inhibitor IkB{alpha}. These effects, accompanied by increased production of H{sub 2}O{sub 2}, were very similar to those observed after incubation with bacterial lipopolysaccharide (LPS) and were inhibited by catalase. These results suggest that apocynin, similarly to LPS, induces increased NO synthesis by eliciting a generation of reactive oxygen species (ROS), which in turn causes NF-{kappa}B activation and increased expression of iNOS. Therefore, the increased bioavailability of NO reported in the literature after in vivo or in vitro treatments with apocynin might depend, at least partly, on the drug-elicited induction of iNOS, and not only on the inhibition of NADPH oxidase and the subsequent decreased scavenging of NO by oxidase-derived ROS, as it is often supposed.

  1. Cholesterol transport through lysosome-peroxisome membrane contacts.

    PubMed

    Chu, Bei-Bei; Liao, Ya-Cheng; Qi, Wei; Xie, Chang; Du, Ximing; Wang, Jiang; Yang, Hongyuan; Miao, Hong-Hua; Li, Bo-Liang; Song, Bao-Liang

    2015-04-01

    Cholesterol is dynamically transported among organelles, which is essential for multiple cellular functions. However, the mechanism underlying intracellular cholesterol transport has remained largely unknown. We established an amphotericin B-based assay enabling a genome-wide shRNA screen for delayed LDL-cholesterol transport and identified 341 hits with particular enrichment of peroxisome genes, suggesting a previously unappreciated pathway for cholesterol transport. We show dynamic membrane contacts between peroxisome and lysosome, which are mediated by lysosomal Synaptotagmin VII binding to the lipid PI(4,5)P2 on peroxisomal membrane. LDL-cholesterol enhances such contacts, and cholesterol is transported from lysosome to peroxisome. Disruption of critical peroxisome genes leads to cholesterol accumulation in lysosome. Together, these findings reveal an unexpected role of peroxisome in intracellular cholesterol transport. We further demonstrate massive cholesterol accumulation in human patient cells and mouse model of peroxisomal disorders, suggesting a contribution of abnormal cholesterol accumulation to these diseases. PMID:25860611

  2. Effect of a Large Dose of Di (2-ethylhexyl) phthalate (DEHP) on Hepatic Peroxisome in Cynomolgus Monkeys (Macaca Fascicularis)

    PubMed Central

    Nakamura, Chika; Minamide, Yoshiyuki; Kudo, Shinobu; Maeda, Hiroshi; Chihaya, Yutaka; Kamimura, Yasuhiro; Miyajima, Hiroaki; Sasaki, Jun; Goryo, Masanobu; Okada, Kosuke

    2010-01-01

    To elucidate the effect of a large dose of di (2-ethylhexyl) phthalate (DEHP), a plasticizer and peroxisome proliferator-activated receptor-? (PPAR?) agonist, on hepatic peroxisomes, we orally administered 1,000 mg/kg/day, once daily, to 3 male and 4 female cynomolgus monkeys for 28 days consecutively. Light-microscopic and electron microscopic examinations of the liver were carried out in conjunction with measurement of the hepatic fatty acid ?-oxidation system (FAOS), carnitine acetyltransferase (CAT) and carnitine palmitoyltransferase (CPT) activities, which are peroxisomal and/or mitochondrial enzyme activities. Electron microscopically, enlargement of the mitochondria was observed with lamellar orientation of the cristae along the major axis. Although the number of peroxisomes showed a tendency to increase when compared with those in a biopsied specimen before treatment, no abnormality in morphology was observed. A slight increase in CPT activity was noted at termination. No changes were noted in hepatic FAOS or CAT activity. In conclusion, although repeated oral treatment of cynomolgus monkeys with a large dose of DEHP induced a subtle increase in the numbers of peroxisomes with slight enlargements of the mitochondria, this low-sensitivity response to peroxisome proliferators in cynomolgus monkeys was considered to be closer to the response in humans than that in rodents. PMID:22272015

  3. HDAC inhibitors induce global changes in histone lysine and arginine methylation and alter expression of lysine demethylases.

    PubMed

    Lillico, Ryan; Sobral, Marina Gomez; Stesco, Nicholas; Lakowski, Ted M

    2016-02-01

    Histone deacetylase (HDAC) inhibitors are cancer treatments that inhibit the removal of the epigenetic modification acetyllysine on histones, resulting in altered gene expression. Such changes in expression may influence other histone epigenetic modifications. We describe a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify lysine acetylation and methylation and arginine methylation on histones extracted from cultured cells treated with HDAC inhibitors. The HDAC inhibitors vorinostat, mocetinostat and entinostat induced 400-600% hyperacetylation in HEK 293 and K562 cells. All HDAC inhibitors decreased histone methylarginines in HEK 293 cells but entinostat produced dose dependent reductions in asymmetric dimethylarginine, not observed in K562 cells. Vorinostat produced increases in histone lysine methylation and decreased expression of some lysine demethylases (KDM), measured by quantitative PCR. Entinostat had variable effects on lysine methylation and decreased expression of some KDM while increasing expression of others. Mocetinostat produced dose dependent increases in histone lysine methylation by LC-MS/MS. This was corroborated with a multiplex colorimetric assay showing increases in histone H3 lysine 4, 9, 27, 36 and 79 methylation. Increases in lysine methylation were correlated with dose dependent decreases in the expression of seven KDM. Mocetinostat functions as an HDAC inhibitor and a de facto KDM inhibitor. PMID:26721445

  4. Dietary Inulin Fibers Prevent Proton-Pump Inhibitor (PPI)-Induced Hypocalcemia in Mice

    PubMed Central

    Hess, Mark W.; de Baaij, Jeroen H. F.; Gommers, Lisanne M. M.; Hoenderop, Joost G. J.; Bindels, René J. M.

    2015-01-01

    Background Proton-pump inhibitor-induced hypomagnesemia (PPIH) is the most recognized side effect of proton-pump inhibitors (PPIs). Additionally, PPIH is associated with hypocalcemia and hypokalemia. It is hypothesized that PPIs reduce epithelial proton secretion and thereby increase the pH in the colon, which may explain the reduced absorption of and Mg2+ and Ca2+. Fermentation of dietary oligofructose-enriched inulin fibers by the microflora leads to acidification of the intestinal lumen and by this enhances mineral uptake. This study aimed, therefore, to improve mineral absorption by application of dietary inulin to counteract PPIH. Methods Here, C57BL/J6 mice were supplemented with omeprazole and/or inulin. Subsequently, Mg2+ and Ca2+ homeostasis was assessed by means of serum, urine and fecal electrolyte measurements. Moreover, the mRNA levels of magnesiotropic and calciotropic genes were examined in the large intestine and kidney by real-time PCR. Results Treatment with omeprazole significantly reduced serum Mg2+ and Ca2+ levels. However, concomitant addition of dietary inulin fibers normalized serum Ca2+ but not serum Mg2+ concentrations. Inulin abolished enhanced expression of Trpv6 and S100g in the colon by omeprazole. Additionally, intestinal and renal mRNA levels of the Trpm6 gene were reduced after inulin intake. Conclusions This study suggests that dietary inulin counteracts reduced intestinal Ca2+ absorption upon PPI treatment. In contrast, inulin did not increase intestinal absorption of Mg2+ sufficiently to recover serum Mg2+. The clinical potential of dietary inulin treatment should be the subject of future studies. PMID:26397986

  5. 11?-Hydroxysteroid dehydrogenase type 1 selective inhibitor BVT.2733 protects osteoblasts against endogenous glucocorticoid induced dysfunction.

    PubMed

    Wu, Lin; Qi, Hanmei; Zhong, Yi; Lv, Shan; Yu, Jing; Liu, Juan; Wang, Long; Bi, Jianhua; Kong, Xiaocen; Di, Wenjuan; Zha, Juanmin; Liu, Feng; Ding, Guoxian

    2013-01-01

    Pharmacologic glucocorticoids (GCs) inhibit osteoblast function and induce osteoporosis. 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1) may play a role in osteoporosis as it regulates GC action at a pre-receptor level by converting inactive GC to its active form. Further, 11?-HSD1 was found increasingly expressed in bone with age. In spite of these observations, its function in senile osteoporosis remains uncertain. In this study we constructed a lentiviral vector overexpressing mouse 11?-HSD1 and then MC3T3-E1 preosteoblast cells were infected by the negative control lentivirus and 11?-HSD1-overexpressing lentivirus, respectively. The mRNA and protein levels of 11?-HSD1 were significantly increased in MC3T3-E1 cells that were infected by 11?-HSD1-overexpressing lentivirus compared to the cells infected by the negative control lentivirus. The osteogenic differentiation of MC3T3-E1 preosteoblast cells was dramatically suppressed by 11?-HSD1 overexpression under the reductase substrate dehydrocorticosterone (DHC). The inhibition effect was similar to the inhibition of osteogenesis by over-dose GCs, including ALP activity, the ultimate calcium nodus formation as well as the expression of the osteogenic genes such as ALP, BSP, OPN and OCN. However, with addition of BVT.2733, a selective inhibitor of 11?-HSD1, all of the above osteogenic repression effects by 11?-HSD1 overexpression were reversed. Furthermore, a GC receptor antagonist RU486 also showed the similar effect, preventing inhibition of osteogenesis by 11?-HSD1 overexpression. These results demonstrated that the specific 11?-HSD1 inhibitor BVT.2733 can reverse the suppression effect towards osteogenic differentiation in 11?-HSD1 overexpressed MC3T3-E1 cells. Inhibition of 11?-HSD1 can be a new therapeutic strategy for senile osteoporosis. PMID:23759754

  6. Human MX2 is an interferon-induced post-entry inhibitor of HIV-1 infection

    PubMed Central

    Goujon, Caroline; Moncorgé, Olivier; Bauby, Hélène; Doyle, Tomas; Ward, Christopher C.; Schaller, Torsten; Hué, Stéphane; Barclay, Wendy S.; Schulz, Reiner; Malim, Michael H.

    2013-01-01

    Animal cells harbour multiple innate effector mechanisms that inhibit virus replication. For the pathogenic retrovirus human immunodeficiency virus type-1 (HIV-1), these include widely expressed restriction factors1 such as APOBEC3 proteins2, TRIM5α3, tetherin/BST24,5 and SAMHD16,7, as well as additional factors that are stimulated by type-1 interferon (IFN)8,9,10,11,12,13,14. Here, we employ both ectopic expression and gene silencing experiments to define the human dynamin-like, IFN-induced guanosine triphosphatase (GTPase), myxovirus resistance 2 (MX2 or MxB) protein, as a potent inhibitor of HIV-1 infection and as a major effector of IFNα-mediated resistance to HIV-1 infection. MX2 suppresses infection by all HIV-1 strains tested, has similar to modest effects on divergent simian immunodeficiency viruses (SIVs), and does not inhibit other retroviruses such as murine leukaemia virus (MLV). The capsid (CA) region of the viral Gag protein dictates susceptibility to MX2, and the block to infection occurs at a late post-entry step with the nuclear accumulation and chromosomal integration of nascent viral cDNA both being suppressed. Finally, human MX1 (or MxA), a closely related protein that has long been recognised as a broadly acting inhibitor of RNA/DNA viruses, including the orthomyxovirus influenza A virus15,16, does not affect HIV-1,whereas MX2 is ineffective against influenza virus. MX2 is therefore a cell-autonomous, anti-HIV-1 resistance factor whose purposeful mobilisation may represent a new therapeutic approach for the treatment of HIV/AIDS. PMID:24048477

  7. Proteasome inhibitor-induced apoptosis of glioma cells involves the processing of multiple caspases and cytochrome c release.

    PubMed

    Wagenknecht, B; Hermisson, M; Groscurth, P; Liston, P; Krammer, P H; Weller, M

    2000-12-01

    The proteasome is a multiprotein complex that is involved in the intracellular protein degradation in eukaryotes. Here, we show that human malignant glioma cells are susceptible to apoptotic cell death induced by the proteasome inhibitors, MG132 and lactacystin. The execution of the apoptotic death program involves the processing of caspases 2, 3, 7, 8, and 9. Apoptosis is inhibited by ectopic expression of X-linked inhibitor of apoptosis (XIAP) and by coexposure to the broad-spectrum caspase inhibitor, benzoyl-VAD-fluoromethyl ketone (zVAD-fmk), but not by the preferential caspase 8 inhibitor, crm-A. It is interesting that specific morphological alterations induced by proteasome inhibition, such as dilated rough endoplasmic reticulum and the formation of cytoplasmic vacuoles and dense mitochondrial deposits, are unaffected by zVAD-fmk. Apoptosis is also inhibited by ectopic expression of Bcl-2 or by an inhibitor of protein synthesis, cycloheximide. Further, cytochrome c release and disruption of mitochondrial membrane potential are prominent features of apoptosis triggered by proteasome inhibition. Bcl-2 is a stronger inhibitor of cytochrome c release than zVAD-fmk. XIAP and crm-A fail to modulate cytochrome c release. These data place cytochrome c release downstream of Bcl-2 activity but upstream of XIAP- and crm-A-sensitive caspases. The partial inhibition of cytochrome c release by zVAD-fmk indicates a positive feedback loop that may involve cytochrome c release and zVAD-fmk-sensitive caspases. Finally, death ligand/receptor interactions, including the CD95/CD95 ligand system, do not mediate apoptosis induced by proteasome inhibition in human malignant glioma cells. PMID:11080180

  8. SLCO1B1 Variants and Angiotensin Converting Enzyme Inhibitor (Enalapril) -Induced Cough: a Pharmacogenetic Study

    PubMed Central

    Luo, Jian-Quan; He, Fa-Zhong; Wang, Zhen-Min; Sun, Ning-Ling; Wang, Lu-Yan; Tang, Gen-Fu; Liu, Mou-Ze; Li, Qing; Chen, Xiao-Ping; Liu, Zhao-Qian; Zhou, Hong-Hao; Zhang, Wei

    2015-01-01

    Clinical observations suggest that incidence of cough in Chinese taking angiotensin converting enzyme inhibitors is much higher than other racial groups. Cough is the most common adverse reaction of enalapril. We investigate whether SLCO1B1 genetic polymorphisms, previously reported to be important determinants of inter-individual variability in enalapril pharmacokinetics, are associated with the enalapril-induced cough. A cohort of 450 patients with essential hypertension taking 10 mg enalapril maleate were genotyped for the functional SLCO1B1 variants, 388A > G (Asn130Asp, rs2306283) and 521T > C (Val174Ala, rs4149056). The primary endpoint was cough, which was recorded when participants were bothered by cough and respiratory symptoms during enalapril treatment without an identifiable cause. SLCO1B1 521C allele conferred a 2-fold relative risk of enalapril-induced cough (95% confidence interval [CI] = 1.34–3.04, P = 6.2 × 10−4), and haplotype analysis suggested the relative risk of cough was 6.94-fold (95% CI = 1.30–37.07, P = 0.020) in SLCO1B1*15/*15 carriers. Furthermore, there was strong evidence for a gene-dose effect (percent with cough in those with 0, 1, or 2 copy of the 521C allele: 28.2%, 42.5%, and 71.4%, trend P = 6.6 × 10−4). Our study highlights, for the first time, SLCO1B1 variants are strongly associated with an increased risk of enalapril-induced cough. The findings will be useful to provide pharmacogenetic markers for enalapril treatment. PMID:26607661

  9. Trichostatin A, a histone deacetylase inhibitor, modulates unloaded-induced skeletal muscle atrophy.

    PubMed

    Dupr-Aucouturier, Sylvie; Castells, Josiane; Freyssenet, Damien; Desplanches, Dominique

    2015-08-15

    Skeletal muscle atrophy is commonly associated with immobilization, ageing, and catabolic diseases such as diabetes and cancer cachexia. Epigenetic regulation of gene expression resulting from chromatin remodeling through histone acetylation has been implicated in muscle disuse. The present work was designed to test the hypothesis that treatment with trichostatin A (TSA), a histone deacetylase inhibitor, would partly counteract unloading-induced muscle atrophy. Soleus muscle atrophy (-38%) induced by 14 days of rat hindlimb suspension was reduced to only 25% under TSA treatment. TSA partly prevented the loss of type I and IIa fiber size and reversed the transitions of slow-twitch to fast-twitch fibers in soleus muscle. Unloading or TSA treatment did not affect myostatin gene expression and follistatin protein. Soleus protein carbonyl content remained unchanged, whereas the decrease in glutathione vs. glutathione disulfide ratio and the increase in catalase activity (biomarkers of oxidative stress) observed after unloading were abolished by TSA treatment. The autophagy-lysosome pathway (Bnip3 and microtubule-associated protein 1 light chain 3 proteins, Atg5, Gabarapl1, Ulk1, and cathepsin B and L mRNA) was not activated by unloading or TSA treatment. However, TSA suppressed the rise in muscle-specific RING finger protein 1 (MuRF1) caused by unloading without affecting the forkhead box (Foxo3) transcription factor. Prevention of muscle atrophy by TSA might be due to the regulation of the skeletal muscle atrophy-related MuRF1 gene. Our findings suggest that TSA may provide a novel avenue to treat unloaded-induced muscle atrophy. PMID:26112243

  10. Epilepsy and hippocampal neurodegeneration induced by glutamate decarboxylase inhibitors in awake rats.

    PubMed

    Salazar, Patricia; Tapia, Ricardo

    2015-10-01

    Glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis, requires pyridoxal phosphate (PLP) as a cofactor. Thiosemicarbazide (TSC) and ?-glutamyl-hydrazone (PLPGH) inhibit the free PLP-dependent isoform (GAD65) activity after systemic administration, leading to epilepsy in mice and in young, but not in adult rats. However, the competitive GAD inhibitor 3-mercaptopropionic acid (MPA) induces convulsions in both immature and adult rats. In the present study we tested comparatively the epileptogenic and neurotoxic effects of PLPGH, TSC and MPA, administered by microdialysis in the hippocampus of adult awake rats. Cortical EEG and motor behavior were analyzed during the next 2h, and aspartate, glutamate and GABA were measured by HPLC in the microdialysis-collected fractions. Twenty-four hours after drug administration rats were fixed for histological analysis of the hippocampus. PLPGH or TSC did not affect the motor behavior, EEG or cellular morphology, although the extracellular concentration of GABA was decreased. In contrast, MPA produced intense wet-dog shakes, EEG epileptiform discharges, a >75% reduction of extracellular GABA levels and remarkable neurodegeneration of the CA1 region, with >80% neuronal loss. The systemic administration of the NMDA glutamate receptor antagonist MK-801 30 min before MPA did not prevent the MPA-induced epilepsy but significantly protected against its neurotoxic effect, reducing neuronal loss to <30%. We conclude that in adult awake rats, drugs acting on PLP availability have only a weak effect on GABA neurotransmission, whereas direct GAD inhibition produced by MPA induces hyperexcitation leading to epilepsy and hippocampal neurodegeneration. Because this degeneration was prevented by the blockade of NMDA receptors, we conclude that it is due to glutamate-mediated excitotoxicity consequent to disinhibition of the hippocampal excitatory circuits. PMID:26354164

  11. Simotinib as a modulator of P-glycoprotein: substrate, inhibitor, or inducer?

    PubMed

    Huang, Lingling; Shen, Cheng; Chen, Yanfen; Yan, Huiwen; Cheng, Zeneng; Zhu, Qubo

    2016-04-01

    As a new antitumor drug, simotinib hydrochloride is prescribed for prolonged periods, often to patients with comorbidities. Therefore, the risk for developing drug resistance and drug-drug interactions between simotinib and other agents has to be taken into consideration. As P-glycoprotein (P-gp) is an efflux transporter, which plays a significant role in drug resistance and influences the pharmacological properties and toxicities of the drugs it interacts with, the interactions between simotinib and P-gp were investigated. Cytotoxicity was measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular drug concentrations were detected by high-performance liquid chromatography, fluorescence-activated cell sorting and using a fluorescence reader. P-gp ATPase activity was measured using the Pgp-Glo assay, and intracellular pH was assessed using the fluorescent probe 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl. The expression and transcription of P-gp were detected by western blotting and the luciferase assay. Simotinib has no cross-resistance to P-gp substrates, and its efflux rate was independent of either the P-gp expression or the coadministered P-gp substrate. Simotinib reversed chemotherapeutic agent resistance in a short time by increasing the intracellular concentration of the chemotherapeutic agent and blocked rhodamine 123 efflux. Further studies demonstrated that simotinib inhibited P-gp activity by modulating its ATPase activity and the intracellular pH. Although simotinib induced P-gp expression after extended treatment, the induced expression of P-gp had little impact on drug resistance. Simotinib is not a substrate of P-gp. As a modulator, it functions mainly as an inhibitor of P-gp by modulating the intracellular pH and ATPase activity, although it also induces P-gp expression after extended treatment. PMID:26766493

  12. Substrate and Inhibitor-induced Dimerization and Cooperativity in Caspase-1 but Not Caspase-3*

    PubMed Central

    Datta, Debajyoti; McClendon, Christopher L.; Jacobson, Matthew P.; Wells, James A.

    2013-01-01

    Caspases are intracellular cysteine-class proteases with aspartate specificity that is critical for driving processes as diverse as the innate immune response and apoptosis, exemplified by caspase-1 and caspase-3, respectively. Interestingly, caspase-1 cleaves far fewer cellular substrates than caspase-3 and also shows strong positive cooperativity between the two active sites of the homodimer, unlike caspase-3. Biophysical and kinetic studies here present a molecular basis for this difference. Analytical ultracentrifugation experiments show that mature caspase-1 exists predominantly as a monomer under physiological concentrations that undergoes dimerization in the presence of substrate; specifically, substrate binding shifts the KD for dimerization by 20-fold. We have created a hemi-active site-labeled dimer of caspase-1, where one site is blocked with the covalent active site inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. This hemi-labeled enzyme is about 9-fold more active than the apo-dimer of caspase-1. These studies suggest that substrate not only drives dimerization but also, once bound to one site in the dimer, promotes an active conformation in the other monomer. Steady-state kinetic analysis and modeling independently support this model, where binding of one substrate molecule not only increases substrate binding in preformed dimers but also drives the formation of heterodimers. Thus, the cooperativity in caspase-1 is driven both by substrate-induced dimerization as well as substrate-induced activation. Substrate-induced dimerization and activation seen in caspase-1 and not in caspase-3 may reflect their biological roles. Whereas caspase-1 cleaves a dramatically smaller number of cellular substrates that need to be concentrated near inflammasomes, caspase-3 is a constitutively active dimer that cleaves many more substrates located diffusely throughout the cell. PMID:23386603

  13. Pex19 Binds Multiple Peroxisomal Membrane Proteins, Is Predominantly Cytoplasmic, and Is Required for Peroxisome Membrane Synthesis

    PubMed Central

    Sacksteder, Katherine A.; Jones, Jacob M.; South, Sarah T.; Li, Xiaoling; Liu, Yifei; Gould, Stephen J.

    2000-01-01

    Peroxisomes are components of virtually all eukaryotic cells. While much is known about peroxisomal matrix protein import, our understanding of how peroxisomal membrane proteins (PMPs) are targeted and inserted into the peroxisome membrane is extremely limited. Here, we show that PEX19 binds a broad spectrum of PMPs, displays saturable PMP binding, and interacts with regions of PMPs required for their targeting to peroxisomes. Furthermore, mislocalization of PEX19 to the nucleus leads to nuclear accumulation of newly synthesized PMPs. At steady state, PEX19 is bimodally distributed between the cytoplasm and peroxisome, with most of the protein in the cytoplasm. We propose that PEX19 may bind newly synthesized PMPs and facilitate their insertion into the peroxisome membrane. This hypothesis is supported by the observation that the loss of PEX19 results in degradation of PMPs and/or mislocalization of PMPs to the mitochondrion. PMID:10704444

  14. Small molecule inhibitors of a glycoside hydrolase attenuate inducible AmpC-mediated beta-lactam resistance.

    PubMed

    Stubbs, Keith A; Balcewich, Misty; Mark, Brian L; Vocadlo, David J

    2007-07-20

    The increasing spread of plasmid-borne ampC-ampR operons is of considerable medical importance, since the AmpC beta-lactamases they encode confer high level resistance to many third generation cephalosporins. Induction of AmpC beta-lactamase from endogenous or plasmid-borne ampC-ampR operons is mediated by a catabolic inducer molecule, 1,6-anhydro-N-acetylmuramic acid (MurNAc) tripeptide, an intermediate of the cell wall recycling pathway derived from the peptidoglycan. Here we describe a strategy for attenuating the antibiotic resistance associated with the ampC-ampR operon by blocking the formation of the inducer molecule using small molecule inhibitors of NagZ, the glycoside hydrolase catalyzing the formation of this inducer molecule. The structure of the NagZ-inhibitor complex provides insight into the molecular basis for inhibition and enables the development of inhibitors with 100-fold selectivity for NagZ over functionally related human enzymes. These PUGNAc-derived inhibitors reduce the minimal inhibitory concentration (MIC) values for several clinically relevant cephalosporins in both wild-type and AmpC-hyperproducing strains lacking functional AmpD. PMID:17439950

  15. HSP90 Inhibitors, Geldanamycin and Radicicol, Enhance Fisetin-Induced Cytotoxicity via Induction of Apoptosis in Human Colonic Cancer Cells.

    PubMed

    Wu, Ming-Shun; Lien, Gi-Shih; Shen, Shing-Chuan; Yang, Liang-Yo; Chen, Yen-Chou

    2013-01-01

    We revealed the cytotoxic effect of the flavonoid, fisetin (FIS), on human COLO205 colon cancer cells in the presence and absence of the HSP90 inhibitors, geldanamycin (GA) and radicicol (RAD). Compared to FIS treatment alone of COLO205 cells, GA and RAD significantly enhanced FIS-induced cytotoxicity, increased expression of cleaved caspase-3 and the PAPR protein, and produced a greater density of DNA ladder formation. GA and RAD also reduced the MMPs with induction of caspase-9 protein cleavage in FIS-treated COLO205 cells. Increased caspase-3 and -9 activities were detected in COLO205 cells treated with FIS+GA or FIS+RAD, and the intensity of DNA ladder formation induced by FIS+GA was reduced by adding the caspase-3 inhibitor, DEVD-FMK. A decrease in Bcl-2 but not Bcl-XL or Bax protein by FIS+GA or FIS+RAD was identified in COLO205 cells by Western blotting. A reduction in p53 protein with increased ubiquitin-tagged proteins was observed in COLO205 cells treated with FIS+GA or FIS+RAD. Furthermore, GA and RAD reduced the stability of the p53 protein in COLO205 cells under FIS stimulation. The evidence supports HSP90 inhibitors possibly sensitizing human colon cancer cells to FIS-induced apoptosis, and treating colon cancer by combining HSP90 inhibitors with FIS deserves further in vivo study. PMID:23840275

  16. HSP90 Inhibitors, Geldanamycin and Radicicol, Enhance Fisetin-Induced Cytotoxicity via Induction of Apoptosis in Human Colonic Cancer Cells

    PubMed Central

    Wu, Ming-Shun; Lien, Gi-Shih; Shen, Shing-Chuan; Yang, Liang-Yo; Chen, Yen-Chou

    2013-01-01

    We revealed the cytotoxic effect of the flavonoid, fisetin (FIS), on human COLO205 colon cancer cells in the presence and absence of the HSP90 inhibitors, geldanamycin (GA) and radicicol (RAD). Compared to FIS treatment alone of COLO205 cells, GA and RAD significantly enhanced FIS-induced cytotoxicity, increased expression of cleaved caspase-3 and the PAPR protein, and produced a greater density of DNA ladder formation. GA and RAD also reduced the MMPs with induction of caspase-9 protein cleavage in FIS-treated COLO205 cells. Increased caspase-3 and -9 activities were detected in COLO205 cells treated with FIS+GA or FIS+RAD, and the intensity of DNA ladder formation induced by FIS+GA was reduced by adding the caspase-3 inhibitor, DEVD-FMK. A decrease in Bcl-2 but not Bcl-XL or Bax protein by FIS+GA or FIS+RAD was identified in COLO205 cells by Western blotting. A reduction in p53 protein with increased ubiquitin-tagged proteins was observed in COLO205 cells treated with FIS+GA or FIS+RAD. Furthermore, GA and RAD reduced the stability of the p53 protein in COLO205 cells under FIS stimulation. The evidence supports HSP90 inhibitors possibly sensitizing human colon cancer cells to FIS-induced apoptosis, and treating colon cancer by combining HSP90 inhibitors with FIS deserves further in vivo study. PMID:23840275

  17. The novel HDAC inhibitor AR-42-induced anti-colon cancer cell activity is associated with ceramide production.

    PubMed

    Xu, Weihong; Xu, Bin; Yao, Yiting; Yu, Xiaoling; Shen, Jie

    2015-08-01

    In the current study, we investigated the potential activity of AR-42, a novel histone deacetylase (HDAC) inhibitor, against colon cancer cells. Our invitro results showed that AR-42 induced ceramide production, exerted potent anti-proliferative and pro-apoptotic activities in established (SW-620 and HCT-116 lines) and primary human colon cancer cells. Exogenously-added sphingosine 1-phosphate (S1P) suppressed AR-42-induced activity, yet a cell-permeable ceramide (C4) facilitated AR-42-induced cytotoxicity against colon cancer cells. In addition, AR-42-induced ceramide production and anti-colon cancer cell activity were inhibited by the ceramide synthase inhibitor fumonisin B1, but were exacerbated by PDMP, which is a ceramide glucosylation inhibitor. Invivo, oral administration of a single dose of AR-42 dramatically inhibited SW-620 xenograft growth in severe combined immunodeficient (SCID) mice, without inducing overt toxicities. Together, these results show that AR-42 dramatically inhibits colon cancer cell proliferation invitro and invivo, and ceramide production might be the key mechanism responsible for its actions. PMID:26026677

  18. Suppression of Rat Oral Carcinogenesis by Agonists of Peroxisome Proliferator Activated Receptor ?

    PubMed Central

    McCormick, David L.; Horn, Thomas L.; Johnson, William D.; Peng, Xinjian; Lubet, Ronald A.; Steele, Vernon E.

    2015-01-01

    Peroxisome-proliferator-activated receptor ? (PPAR?) is a ligand-activated transcription factor that regulates cell proliferation, differentiation, and apoptosis. In vivo studies were performed to evaluate the activities of two thiazolidinedione PPAR? agonists, rosiglitazone and pioglitazone, as inhibitors of oral carcinogenesis in rats. Oral squamous cell carcinomas (OSCC) were induced in male F344 rats by 4-nitroquinoline-1-oxide (NQO; 20 ppm in the drinking water for 10 weeks). In each study, groups of 30 NQO-treated rats were exposed to a PPAR? agonist beginning at week 10 (one day after completion of NQO administration) or at week 17 (7 weeks post-NQO); chemopreventive agent exposure was continued until study termination at week 22 (rosiglitazone study) or week 24 (pioglitazone study). Administration of rosiglitazone (800 mg/kg diet) beginning at week 10 increased survival, reduced oral cancer incidence, and reduced oral cancer invasion score in comparison to dietary controls; however, chemopreventive activity was largely lost when rosiglitazone administration was delayed until week 17. Administration of pioglitazone (500 mg/kg diet beginning at week 10 or 1000 mg/kg diet beginning at week 17) induced significant reductions in oral cancer incidence without significant effects on OSCC invasion scores. Transcript levels of PPAR? and its three transcriptional variants (PPAR?v1, PPAR?v2, and PPAR?v3) were not significantly different in OSCC versus age- and site-matched phenotypically normal oral tissues from rats treated with NQO. These data suggest that PPAR? provides a useful molecular target for oral cancer chemoprevention, and that overexpression of PPAR? at the transcriptional level in neoplastic lesions is not essential for chemopreventive efficacy. PMID:26516762

  19. Interaction of ligands for the peroxisome proliferator-activated receptor γ with the endocannabinoid system

    PubMed Central

    Lenman, A; Fowler, C J

    2007-01-01

    Background and purpose: There is good evidence that agents interacting with the endocannabinoid system in the body can also interact with the peroxisome proliferator-activated receptor γ. The present study was designed to test whether the reverse is true, namely whether peroxisome proliferator-activated receptor γ ligands have direct effects upon the activity of the endocannabinoid metabolizing enzyme fatty acid amide hydrolase. Experimental approach: Fatty acid amide hydrolase activity was measured in rat brain homogenates, C6 glioma and RBL2H3 basophilic leukaemia cells. Cellular uptake of anandamide was also assessed in these cells. Key results: Peroxisome proliferator-activated receptor γ activators inhibited the metabolism of the endocannabinoid anandamide in rat brain homogenates with an order of potency MCC-555 > indomethacin ≈ ciglitazone ≈ 15-deoxy-Δ12,14-prostaglandin J2 ≈ pioglitazone > rosiglitazone > troglitazone. The antagonists BADGE, GW9662 and T0070907 were poor inhibitors of anandamide hydrolysis. The inhibition by ciglitazone was competitive and increased as the pH of the assay buffer was decreased; the Ki value at pH 6.0 was 17 μM. In intact C6 glioma cells assayed at pH 6.2, significant inhibition of anandamide hydrolysis was seen at 3 μM ciglitazone, whereas 100 μM was required to produce significant inhibition at pH 7.4. Ciglitazone also interacted with monoacylglycerol lipase as well as with cannabinoid CB1 and CB2 receptors. Conclusions and implications: Ciglitazone may be useful as a template for the design of novel dual action anti-inflammatory agents which are both inhibitors of fatty acid amide hydrolase and agonists at the peroxisome proliferator-activated receptor γ. PMID:17592505

  20. Fatty Acid Synthase Inhibitors Induce Apoptosis in Non-Tumorigenic Melan-A Cells Associated with Inhibition of Mitochondrial Respiration

    PubMed Central

    Rossato, Franco A.; Zecchin, Karina G.; La Guardia, Paolo G.; Ortega, Rose M.; Alberici, Luciane C.; Costa, Rute A. P.; Catharino, Rodrigo R.; Graner, Edgard; Castilho, Roger F.; Vercesi, Aníbal E.

    2014-01-01

    The metabolic enzyme fatty acid synthase (FASN) is responsible for the endogenous synthesis of palmitate, a saturated long-chain fatty acid. In contrast to most normal tissues, a variety of human cancers overexpress FASN. One such cancer is cutaneous melanoma, in which the level of FASN expression is associated with tumor invasion and poor prognosis. We previously reported that two FASN inhibitors, cerulenin and orlistat, induce apoptosis in B16-F10 mouse melanoma cells via the intrinsic apoptosis pathway. Here, we investigated the effects of these inhibitors on non-tumorigenic melan-a cells. Cerulenin and orlistat treatments were found to induce apoptosis and decrease cell proliferation, in addition to inducing the release of mitochondrial cytochrome c and activating caspases-9 and -3. Transfection with FASN siRNA did not result in apoptosis. Mass spectrometry analysis demonstrated that treatment with the FASN inhibitors did not alter either the mitochondrial free fatty acid content or composition. This result suggests that cerulenin- and orlistat-induced apoptosis events are independent of FASN inhibition. Analysis of the energy-linked functions of melan-a mitochondria demonstrated the inhibition of respiration, followed by a significant decrease in mitochondrial membrane potential (ΔΨm) and the stimulation of superoxide anion generation. The inhibition of NADH-linked substrate oxidation was approximately 40% and 61% for cerulenin and orlistat treatments, respectively, and the inhibition of succinate oxidation was approximately 46% and 52%, respectively. In contrast, no significant inhibition occurred when respiration was supported by the complex IV substrate N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). The protection conferred by the free radical scavenger N-acetyl-cysteine indicates that the FASN inhibitors induced apoptosis through an oxidative stress-associated mechanism. In combination, the present results demonstrate that cerulenin and orlistat induce apoptosis in non-tumorigenic cells via mitochondrial dysfunction, independent of FASN inhibition. PMID:24964211

  1. Inhibitors of poly-(adenosine diphosphoribose) synthesis slow the resealing rate of x-ray induced DNA strand breaks

    SciTech Connect

    Zwelling, L.A.; Kerrigan, D.; Pommier, Y.

    1982-02-11

    The rate of resealing of x-ray-induced DNA single-strand breaks was measured in L1210 cells in the absence and presence of inhibitors of poly-(adenosine diphosphoribose) synthesis by the alkaline elution technique. Both 5-methylnicotinamide and 3-aminobenzamide slowed, but did not prevent x-ray-induced DNA break resealing. The ability of cellular DNA to repair over 90% of x-ray-induced strand breaks under conditions of poly-(adenosine diphosphoribose) synthesis inhibition suggests that x-ray break resealing may proceed in two ways, one associated with poly-(adenosine diphosphoribose) synthesis and one independent of its synthesis.

  2. Regulation of peroxisomal matrix protein import by ubiquitination.

    PubMed

    Platta, Harald W; Brinkmeier, Rebecca; Reidick, Christina; Galiani, Silvia; Clausen, Mathias P; Eggeling, Christian

    2016-05-01

    Peroxisomes are organelles that play an important role in many cellular tasks. The functionality of peroxisomes depends on the proper import of their matrix proteins. Peroxisomal matrix proteins are imported posttranslationally in a folded, sometimes even oligomeric state. They harbor a peroxisomal targeting sequence (PTS), which is recognized by dynamic PTS-receptors in the cytosol. The PTS-receptors ferry the cargo to the peroxisomal membrane, where they become part of a transient import pore and then release the cargo into the peroxisomal lumen. Subsequentially, the PTS-receptors are ubiquitinated in order to mark them for the export-machinery, which releases them back to the cytosol. Upon deubiquitination, the PTS-receptors can facilitate further rounds of cargo import. Because the ubiquitination of the receptors is an essential step in the import cycle, it also represents a central regulatory element that governs peroxisomal dynamics. In this review we want to give an introduction to the functional role played by ubiquitination during peroxisomal protein import and highlight the mechanistic concepts that have emerged based on data derived from different species since the discovery of the first ubiquitinated peroxin 15years ago. Moreover, we discuss future tasks and the potential of using advanced technologies for investigating further details of peroxisomal protein transport. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26367801

  3. OCTN3 is a mammalian peroxisomal membrane carnitine transporter

    SciTech Connect

    Lamhonwah, Anne-Marie; Ackerley, Cameron A.; Tilups, Aina; Edwards, Vernon D.; Wanders, Ronald J.; Tein, Ingrid . E-mail: ingrid.tein@sickkids.ca

    2005-12-30

    Carnitine is a zwitterion essential for the {beta}-oxidation of fatty acids. The role of the carnitine system is to maintain homeostasis in the acyl-CoA pools of the cell, keeping the acyl-CoA/CoA pool constant even under conditions of very high acyl-CoA turnover, thereby providing cells with a critical source of free CoA. Carnitine derivatives can be moved across intracellular barriers providing a shuttle mechanism between mitochondria, peroxisomes, and microsomes. We now demonstrate expression and colocalization of mOctn3, the intermediate-affinity carnitine transporter (K {sub m} 20 {mu}M), and catalase in murine liver peroxisomes by TEM using immunogold labelled anti-mOctn3 and anti-catalase antibodies. We further demonstrate expression of hOCTN3 in control human cultured skin fibroblasts both by Western blotting and immunostaining analysis using our specific anti-mOctn3 antibody. In contrast with two peroxisomal biogenesis disorders, we show reduced expression of hOCTN3 in human PEX 1 deficient Zellweger fibroblasts in which the uptake of peroxisomal matrix enzymes is impaired but the biosynthesis of peroxisomal membrane proteins is normal, versus a complete absence of hOCTN3 in human PEX 19 deficient Zellweger fibroblasts in which both the uptake of peroxisomal matrix enzymes as well as peroxisomal membranes are deficient. This supports the localization of hOCTN3 to the peroxisomal membrane. Given the impermeability of the peroxisomal membrane and the key role of carnitine in the transport of different chain-shortened products out of peroxisomes, there appears to be a critical need for the intermediate-affinity carnitine/organic cation transporter, OCTN3, on peroxisomal membranes now shown to be expressed in both human and murine peroxisomes. This Octn3 localization is in keeping with the essential role of carnitine in peroxisomal lipid metabolism.

  4. Transcriptional activation of peroxisome proliferator-activated receptor-{gamma} requires activation of both protein kinase A and Akt during adipocyte differentiation

    SciTech Connect

    Kim, Sang-pil; Ha, Jung Min; Yun, Sung Ji; Kim, Eun Kyoung; Chung, Sung Woon; Hong, Ki Whan; Kim, Chi Dae; Bae, Sun Sik

    2010-08-13

    Research highlights: {yields} Elevated cAMP activates both PKA and Epac. {yields} PKA activates CREB transcriptional factor and Epac activates PI3K/Akt pathway via Rap1. {yields} Akt modulates PPAR-{gamma} transcriptional activity in concert with CREB. -- Abstract: Peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) is required for the conversion of pre-adipocytes. However, the mechanism underlying activation of PPAR-{gamma} is unclear. Here we showed that cAMP-induced activation of protein kinase A (PKA) and Akt is essential for the transcriptional activation of PPAR-{gamma}. Hormonal induction of adipogenesis was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), by a protein kinase A (PKA) inhibitor (H89), and by a Rap1 inhibitor (GGTI-298). Transcriptional activity of PPAR-{gamma} was markedly enhanced by 3-isobutyl-1-methylxanthine (IBMX), but not insulin and dexamethasone. In addition, IBMX-induced PPAR-{gamma} transcriptional activity was blocked by PI3K/Akt, PKA, or Rap1 inhibitors. 8-(4-Chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT-2'-O-Me-cAMP) which is a specific agonist for exchanger protein directly activated by cAMP (Epac) significantly induced the activation of Akt. Furthermore, knock-down of Akt1 markedly attenuated PPAR-{gamma} transcriptional activity. These results indicate that both PKA and Akt signaling pathways are required for transcriptional activation of PPAR-{gamma}, suggesting post-translational activation of PPAR-{gamma} might be critical step for adipogenic gene expression.

  5. Effects of EGFR Inhibitor on Helicobacter pylori Induced Gastric Epithelial Pathology in Vivo

    PubMed Central

    Crabtree, Jean E.; Jeremy, Anthony H.T.; Duval, Cedric; Dixon, Michael F.; Danjo, Kazuma; Carr, Ian M.; Pritchard, D. Mark; Robinson, Philip A.

    2013-01-01

    Helicobacter pylori transactivates the Epidermal Growth Factor Receptor (EGFR) and predisposes to gastric cancer development in humans and animal models. To examine the importance of EGFR signalling to gastric pathology, this study investigated whether treatment of Mongolian gerbils with a selective EGFR tyrosine kinase inhibitor, EKB-569, altered gastric pathology in chronic H. pylori infection. Gerbils were infected with H. pylori and six weeks later received either EKB-569-supplemented, or control diet, for 32 weeks prior to sacrifice. EKB-569-treated H. pylori-infected gerbils had no difference in H. pylori colonisation or inflammation scores compared to infected animals on control diet, but showed significantly less corpus atrophy, mucous metaplasia and submucosal glandular herniations along with markedly reduced antral and corpus epithelial proliferation to apoptosis ratios. EKB-569-treated infected gerbils had significantly decreased abundance of Cox-2, Adam17 and Egfr gastric transcripts relative to infected animals on control diet. EGFR inhibition by EKB-569 therefore reduced the severity of pre-neoplastic gastric pathology in chronically H. pylori-infected gerbils. EKB-569 increased gastric epithelial apoptosis in H. pylori-infected gerbils which counteracted some of the consequences of increased gastric epithelial cell proliferation. Similar chemopreventative strategies may be useful in humans who are at high risk of developing H. pylori- induced gastric adenocarcinoma. PMID:25437333

  6. Novel ALK inhibitor AZD3463 inhibits neuroblastoma growth by overcoming crizotinib resistance and inducing apoptosis

    PubMed Central

    Wang, Yongfeng; Wang, Long; Guan, Shan; Cao, Wenming; Wang, Hao; Chen, Zhenghu; Zhao, Yanling; Yu, Yang; Zhang, Huiyuan; Pang, Jonathan C.; Huang, Sophia L.; Akiyama, Yo; Yang, Yifan; Sun, Wenjing; Xu, Xin; Shi, Yan; Zhang, Hong; Kim, Eugene S.; Muscal, Jodi A.; Lu, Fengmin; Yang, Jianhua

    2016-01-01

    ALK receptor tyrosine kinase has been shown to be a therapeutic target in neuroblastoma. Germline ALK activating mutations are responsible for the majority of hereditary neuroblastoma and somatic ALK activating mutations are also frequently observed in sporadic cases of advanced NB. Crizotinib, a first-line therapy in the treatment of advanced non-small cell lung cancer (NSCLC) harboring ALK rearrangements, demonstrates striking efficacy against ALK-rearranged NB. However, crizotinib fails to effectively inhibit the activity of ALK when activating mutations are present within its kinase domain, as with the F1174L mutation. Here we show that a new ALK inhibitor AZD3463 effectively suppressed the proliferation of NB cell lines with wild type ALK (WT) as well as ALK activating mutations (F1174L and D1091N) by blocking the ALK-mediated PI3K/AKT/mTOR pathway and ultimately induced apoptosis and autophagy. In addition, AZD3463 enhanced the cytotoxic effects of doxorubicin on NB cells. AZD3463 also exhibited significant therapeutic efficacy on the growth of the NB tumors with WT and F1174L activating mutation ALK in orthotopic xenograft mouse models. These results indicate that AZD3463 is a promising therapeutic agent in the treatment of NB. PMID:26786851

  7. Novel ALK inhibitor AZD3463 inhibits neuroblastoma growth by overcoming crizotinib resistance and inducing apoptosis.

    PubMed

    Wang, Yongfeng; Wang, Long; Guan, Shan; Cao, Wenming; Wang, Hao; Chen, Zhenghu; Zhao, Yanling; Yu, Yang; Zhang, Huiyuan; Pang, Jonathan C; Huang, Sophia L; Akiyama, Yo; Yang, Yifan; Sun, Wenjing; Xu, Xin; Shi, Yan; Zhang, Hong; Kim, Eugene S; Muscal, Jodi A; Lu, Fengmin; Yang, Jianhua

    2016-01-01

    ALK receptor tyrosine kinase has been shown to be a therapeutic target in neuroblastoma. Germline ALK activating mutations are responsible for the majority of hereditary neuroblastoma and somatic ALK activating mutations are also frequently observed in sporadic cases of advanced NB. Crizotinib, a first-line therapy in the treatment of advanced non-small cell lung cancer (NSCLC) harboring ALK rearrangements, demonstrates striking efficacy against ALK-rearranged NB. However, crizotinib fails to effectively inhibit the activity of ALK when activating mutations are present within its kinase domain, as with the F1174L mutation. Here we show that a new ALK inhibitor AZD3463 effectively suppressed the proliferation of NB cell lines with wild type ALK (WT) as well as ALK activating mutations (F1174L and D1091N) by blocking the ALK-mediated PI3K/AKT/mTOR pathway and ultimately induced apoptosis and autophagy. In addition, AZD3463 enhanced the cytotoxic effects of doxorubicin on NB cells. AZD3463 also exhibited significant therapeutic efficacy on the growth of the NB tumors with WT and F1174L activating mutation ALK in orthotopic xenograft mouse models. These results indicate that AZD3463 is a promising therapeutic agent in the treatment of NB. PMID:26786851

  8. Histone deacetylase inhibitors prevent activation-induced cell death and promote anti-tumor immunity

    PubMed Central

    Cao, K; Wang, G; Li, W; Zhang, L; Wang, R; Huang, Y; Du, L; Jiang, J; Wu, C; He, X; Roberts, A I; Li, F; Rabson, A B; Wang, Y; Shi, Y

    2015-01-01

    The poor efficacy of the in vivo anti-tumor immune response has been partially attributed to ineffective T-cell responses mounted against the tumor. Fas-FasL-dependent activation-induced cell death (AICD) of T cells is believed to be a major contributor to compromised anti-tumor immunity. The molecular mechanisms of AICD are well-investigated, yet the possibility of regulating AICD for cancer therapy remains to be explored. In this study, we show that histone deacetylase inhibitors (HDACIs) can inhibit apoptosis of CD4+ T cells within the tumor, thereby enhancing anti-tumor immune responses and suppressing melanoma growth. This inhibitory effect is specific for AICD through suppressing NFAT1-regulated FasL expression on activated CD4+ T cells. In gld/gld mice with mutation in FasL, the beneficial effect of HDACIs on AICD of infiltrating CD4+ T cells is not seen, confirming the critical role of FasL regulation in the anti-tumor effect of HDACIs. Importantly, we found that the co-administration of HDACIs and anti-CTLA4 could further enhance the infiltration of CD4+ T cells and achieve a synergistic therapeutic effect on tumor. Therefore, our study demonstrates that the modulation of AICD of tumor-infiltrating CD4+ T cells using HDACIs can enhance anti-tumor immune responses, uncovering a novel mechanism underlying the anti-tumor effect of HDACIs. PMID:25745993

  9. A New Generation Fatty Acid Amide Hydrolase Inhibitor Protects Against Kainate-Induced Excitotoxicity

    PubMed Central

    Naidoo, Vinogran; Nikas, Spyros P.; Karanian, David A.; Hwang, Jeannie; Zhao, Jianhong; Wood, JodiAnne T.; Alapafuja, Shakiru O.; Vadivel, Subramanian K.; Butler, David; Makriyannis, Alexandros; Bahr, Ben A.

    2010-01-01

    Endocannabinoids, including anandamide (AEA), have been implicated in neuroprotective on-demand responses. Related to such a response to injury, an excitotoxic kainic acid (KA) injection (i.p.) was found to increase AEA levels in the brain. To modulate the endocannabinoid response during events of excitotoxicity in vitro and in vivo, we utilized a new generation compound (AM5206) that selectively inhibits the AEA deactivating enzyme fatty acid amide hydrolase (FAAH). KA caused calpain-mediated spectrin breakdown, declines in synaptic markers, and disruption of neuronal integrity in cultured hippocampal slices. FAAH inhibition with AM5206 protected against the neurodegenerative cascade assessed in the slice model 24 h postinsult. In vivo, KA administration induced seizures and the same neurodegenerative events exhibited in vitro. When AM5206 was injected immediately after KA in rats, the seizure scores were markedly reduced as were levels of cytoskeletal damage and synaptic protein decline. The pre- and postsynaptic proteins were protected by the FAAH inhibitor to levels comparable to those found in healthy control brains. These data support the idea that endocannabinoids are released and converge on pro-survival pathways that prevent excitotoxic progression. PMID:21069475

  10. HDAC inhibitor misprocesses bantam oncomiRNA, but stimulates hid induced apoptotic pathway

    PubMed Central

    Bhadra, Utpal; Mondal, Tanmoy; Bag, Indira; Mukhopadhyay, Debasmita; Das, Paromita; Parida, Bibhuti B.; Mainkar, Prathama S.; Reddy, Chada Raji; Bhadra, Manika Pal

    2015-01-01

    Apoptosis or programmed cell death is critical for embryogenesis and tissue homeostasis. Uncontrolled apoptosis leads to different human disorders including immunodeficiency, autoimmune disorder and cancer. Several small molecules that control apoptosis have been identified. Here, we have shown the functional role of triazole derivative (DCPTN-PT) that acts as a potent HDAC inhibitor and mis-express proto onco microRNA (miRNA) bantam. To further understanding the mechanism of action of the molecule in apoptotic pathway, a series of experiments were also performed in Drosophila, a well known model organism in which the nature of human apoptosis is very analogous. DCPTN-PT mis processes bantam microRNA and alters its down regulatory target hid function and cleavage of Caspase-3 which in turn influence components of the mitochondrial apoptotic pathway in Drosophila. However regulatory microRNAs in other pro-apoptotic genes are not altered. Simultaneously, treatment of same molecule also affects the mitochondrial regulatory pathway in human tumour cell lines suggesting its conservative nature between fly and human. It is reasonable to propose that triazole derivative (DCPTN-PT) controls bantam oncomiRNA and increases hid induced apoptosis and is also able to influence mitochondrial apoptotic pathway. PMID:26442596

  11. A novel diacylglycerol kinase ?-selective inhibitor, CU-3, induces cancer cell apoptosis and enhances immune response.

    PubMed

    Liu, Ke; Kunii, Naoko; Sakuma, Megumi; Yamaki, Atsumi; Mizuno, Satoru; Sato, Mayu; Sakai, Hiromichi; Kado, Sayaka; Kumagai, Kazuo; Kojima, Hirotatsu; Okabe, Takayoshi; Nagano, Tetsuo; Shirai, Yasuhito; Sakane, Fumio

    2016-03-01

    Diacylglycerol kinase (DGK) consists of 10 isozymes. The ?-isozyme enhances the proliferation of cancer cells. However, DGK? facilitates the nonresponsive state of immunity known as T-cell anergy; therefore, DGK? enhances malignant traits and suppresses immune surveillance. The aim of this study was to identify a novel small molecule that selectively and potently inhibits DGK? activity. We screened a library containing 9,600 chemical compounds using a newly established high-throughput DGK assay. As a result, we have obtained a promising compound, 5-[(2E)-3-(2-furyl)prop-2-enylidene]-3-[(phenylsulfonyl)amino]2-thioxo-1,3-thiazolidin-4-one) (CU-3), which selectively inhibited DGK? with an IC50 value of 0.6 ?M. CU-3 targeted the catalytic region, but not the regulatory region, of DGK?. CU-3 competitively reduced the affinity of DGK? for ATP, but not diacylglycerol or phosphatidylserine. Moreover, this compound induced apoptosis in HepG2 hepatocellular carcinoma and HeLa cervical cancer cells while simultaneously enhancing the interleukin-2 production of Jurkat T cells. Taken together, these results indicate that CU-3 is a selective and potent inhibitor for DGK? and can be an ideal anticancer drug candidate that attenuates cancer cell proliferation and simultaneously enhances immune responses including anticancer immunity. PMID:26768655

  12. Plasminogen Activator Inhibitor-1 Is Involved in Streptozotocin-Induced Bone Loss in Female Mice

    PubMed Central

    Tamura, Yukinori; Kawao, Naoyuki; Okada, Kiyotaka; Yano, Masato; Okumoto, Katsumi; Matsuo, Osamu; Kaji, Hiroshi

    2013-01-01

    In diabetic patients, the risk of fracture is high because of impaired bone formation. However, the details of the mechanisms in the development of diabetic osteoporosis remain unclear. In the current study, we investigated the role of plasminogen activator inhibitor (PAI)-1 in the pathogenesis of type 1 diabetic osteoporosis by using PAI-1deficient mice. Quantitative computed tomography analysis showed that PAI-1 deficiency protected against streptozotocin-induced bone loss in female mice but not in male mice. PAI-1 deficiency blunted the changes in the levels of Runx2, osterix, and alkaline phosphatase in tibia as well as serum osteocalcin levels suppressed by the diabetic state in female mice only. Furthermore, the osteoclast levels in tibia, suppressed in diabetes, were also blunted by PAI-1 deficiency in female mice. Streptozotocin markedly elevated the levels of PAI-1 mRNA in liver in female mice only. In vitro study demonstrated that treatment with active PAI-1 suppressed the levels of osteogenic genes and mineralization in primary osteoblasts from female mouse calvaria. In conclusion, the current study indicates that PAI-1 is involved in the pathogenesis of type 1 diabetic osteoporosis in females. The expression of PAI-1 in the liver and the sensitivity of bone cells to PAI-1 may be an underlying mechanism. PMID:23715621

  13. Protease inhibitor reduces airway response and underlying inflammation in cockroach allergen-induced murine model.

    PubMed

    Saw, Sanjay; Arora, Naveen

    2015-04-01

    Protease(s) enhances airway inflammation and allergic cascade. In the present study, effect of a serine protease inhibitor was evaluated in mouse model of airway disease. Mice were sensitized with cockroach extract (CE) or Per a 10 and treated with 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) 1 h before or after challenge to measure airway response. Mice were euthanized to collect bronchoalveolar lavage fluid (BALF), blood, and lung to evaluate inflammation. AEBSF treatment significantly reduced the AHR in allergen-challenged mice in dose-dependent manner (p??0.01). IgE (p?0.05) and Th2 cytokines (p?0.05) were significantly reduced in treated mice. AEBSF treatment lowered total cell (p?0.05), eosinophil (p?0.05), and neutrophil (p?0.05) in BALF and lung tissue. Oxidative stress parameters were impaired on treatment in allergen-challenged mice (p?0.05). AEBSF had therapeutic effect in allergen-induced airway resistance and underling inflammation and had potential for combination or as add-on therapy for respiratory diseases. PMID:25052477

  14. Modulation of curcumin-induced Akt phosphorylation and apoptosis by PI3K inhibitor in MCF-7 cells

    SciTech Connect

    Kizhakkayil, Jaleel; Thayyullathil, Faisal; Chathoth, Shahanas; Hago, Abdulkader; Patel, Mahendra; Galadari, Sehamuddin

    2010-04-09

    Curcumin has been shown to induce apoptosis in various malignant cancer cell lines. One mechanism of curcumin-induced apoptosis is through the PI3K/Akt signaling pathway. Akt, also known as protein kinase B (PKB), is a member of the family of phosphatidylinositol 3-OH-kinase regulated Ser/Thr kinases. The active Akt regulates cell survival and proliferation; and inhibits apoptosis. In this study we found that curcumin induces apoptotic cell death in MCF-7 cells, as assessed by MTT assay, DNA ladder formation, PARP cleavage, p53 and Bax induction. At apoptotic inducing concentration, curcumin induces a dramatic Akt phosphorylation, accompanied by an increased phosphorylation of glycogen synthase kinase 3{beta} (GSK3{beta}), which has been considered to be a pro-growth signaling molecule. Combining curcumin with PI3K inhibitor, LY290042, synergizes the apoptotic effect of curcumin. The inhibitor LY290042 was capable of attenuating curcumin-induced Akt phosphorylation and activation of GSK3{beta}. All together, our data suggest that blocking the PI3K/Akt survival pathway sensitizes the curcumin-induced apoptosis in MCF-7 cells.

  15. Exogenous cannabinoids as substrates, inhibitors, and inducers of human drug metabolizing enzymes: a systematic review.

    PubMed

    Stout, Stephen M; Cimino, Nina M

    2014-02-01

    Exogenous cannabinoids are structurally and pharmacologically diverse compounds that are widely used. The purpose of this systematic review is to summarize the data characterizing the potential for these compounds to act as substrates, inhibitors, or inducers of human drug metabolizing enzymes, with the aim of clarifying the significance of these properties in clinical care and drug interactions. In vitro data were identified that characterize cytochrome P-450 (CYP-450) enzymes as potential significant contributors to the primary metabolism of several exogenous cannabinoids: tetrahydrocannabinol (THC; CYPs 2C9, 3A4); cannabidiol (CBD; CYPs 2C19, 3A4); cannabinol (CBN; CYPs 2C9, 3A4); JWH-018 (CYPs 1A2, 2C9); and AM2201 (CYPs 1A2, 2C9). CYP-450 enzymes may also contribute to the secondary metabolism of THC, and UDP-glucuronosyltransferases have been identified as capable of catalyzing both primary (CBD, CBN) and secondary (THC, JWH-018, JWH-073) cannabinoid metabolism. Clinical pharmacogenetic data further support CYP2C9 as a significant contributor to THC metabolism, and a pharmacokinetic interaction study using ketoconazole with oromucosal cannabis extract further supports CYP3A4 as a significant metabolic pathway for THC and CBD. However, the absence of interaction between CBD from oromucosal cannabis extract with omeprazole suggests a less significant role of CYP2C19 in CBD metabolism. Studies of THC, CBD, and CBN inhibition and induction of major human CYP-450 isoforms generally reflect a low risk of clinically significant drug interactions with most use, but specific human data are lacking. Smoked cannabis herb (marijuana) likely induces CYP1A2 mediated theophylline metabolism, although the role of cannabinoids specifically in eliciting this effect is questionable. PMID:24160757

  16. Mx2 is an interferon induced inhibitor of HIV-1 infection

    PubMed Central

    Kane, Melissa; Yadav, Shalini S.; Bitzegeio, Julia; Kutluay, Sebla B.; Zang, Trinity; Wilson, Sam J.; Schoggins, John W.; Rice, Charles M.; Yamashita, Masahiro; Hatziioannou, Theodora; Bieniasz, Paul D.

    2014-01-01

    HIV-1 replication can be inhibited by type-I interferon (IFN), and the expression of a number of gene products with anti HIV-1 activity is induced by type-I IFN1,2. However, none of the known antiretroviral proteins can account for the ability of type-I IFN to inhibit early, preintegration, phases of the HIV-1 replication cycle in human cells3,4. By comparing gene expression profiles in cell lines that differ in their ability to support the inhibitory action of IFN? on early steps of the HIV-1 replication cycle, we identified Myxovirus resistance-2 (Mx2) as an interferon-induced inhibitor of HIV-1 infection. Expression of Mx2 reduced permissiveness to a variety of lentiviruses, while depletion of Mx2 using RNA interference reduced the anti-HIV-1 potency of IFN?. HIV-1 reverse transcription proceeded normally in Mx2-expressing cells, but 2-LTR circular forms of HIV-1 DNA were less abundant, suggesting that Mx2 inhibits HIV-1 nuclear import, or destabilizes nuclear HIV-1 DNA. Consistent with this notion, mutations in the HIV-1 capsid protein that are known, or suspected to alter the nuclear import pathways used by HIV-1 conferred resistance to Mx2, while preventing cell division increased Mx2 potency. Overall, these findings indicate that Mx2 is an effector of the anti-HIV-1 activity of type-I IFN, and suggest that Mx2 inhibits HIV-1 infection by inhibiting capsid-dependent nuclear import of subviral complexes. PMID:24121441

  17. Oxaceprol, an atypical inhibitor of inflammation, reduces leukocyte adherence in mouse antigen-induced arthritis.

    PubMed

    Veihelmann, A; Hofbauer, A; Refior, H J; Messmer, K

    2001-06-01

    Oxaceprol (N-acetyl-L-hydroxyproline), an atypical inhibitor of inflammation, is an established drug forjoint disease without serious side-effects. Recent studies have emphasized that oxaceprol has an effect on the microcirculation. Since the exact mechanism of action remains unclear, the aim of our study was to investigate the leukocyte-endothelial cell interactions in oxaceprol-treated mice with antigen-induced arthritis (AiA) using intravital microscopy. In our study, Balb/c mice were allocated to 4 groups (n 7, 8, 8, 8): 2 control groups with saline or oxaceprol and 2 groups of arthritic animals which received saline or oxaceprol (100 mg/kg twice a day intraperitoneally). The severity of arthritis was quantified by the transverse knee joint diameter. For the intravital fluorescence microscopy measurements on day 10 after inducing arthritis, the patella tendon was partily resected to visualize the intraarticular synovial tissue of the knee joint. The number of rolling and adherent leukocytes as well as RBC velocity and functional capillary density (FCD) were quantified in synovial microvessels. Furthermore, leukocyte infiltration was determined in the histological sections with an established score. No significant changes in mean arterial blood pressure or functional capillary density were found in any of the groups. However, the leukocyte rolling fraction and number of leukocytes adherent to the endothelium were increased in postcapillary venules of the synovium in arthritic animals (0.16 to 0.31, 78 cells/mm2 to 220 cells/mm2). In animals with AiA treated with oxaceprol, leukocyte adherence and swelling were significantly reduced in comparison to the arthritic animals treated with saline. Furthermore, the histological score showed less leukocyte infiltration in the oxaceprol treated arthritic animals. Thus, oxaceprol reduces leukocyte adherence in vivo and leukocyte infiltration in mouse AiA, indicating an effect on synovial microcirculation. PMID:11480608

  18. The calpain inhibitor calpeptin prevents bleomycin-induced pulmonary fibrosis in mice.

    PubMed

    Tabata, C; Tabata, R; Nakano, T

    2010-12-01

    Pulmonary fibrosis is characterized by progressive worsening of pulmonary function leading to a high incidence of death. Currently, however, there has been little progress in therapeutic strategies for pulmonary fibrosis. There have been several reports on cytokines being associated with lung fibrosis, including interleukin (IL)-6 and transforming growth factor (TGF)-?1. We reported recently that two substances (ATRA and thalidomide) have preventive effects on pulmonary fibrosis by inhibiting IL-6-dependent proliferation and TGF-?1-dependent transdifferentiation of lung fibroblasts. Rheumatoid arthritis is a chronic autoimmune disorder, and its pathogenesis is also characterized by an association with several cytokines. It has been reported that calpain, a calcium-dependent intracellular cysteine protease, plays an important role in the progression of rheumatoid arthritis. In this study, we examined the preventive effect of Calpeptin, a calpain inhibitor, on bleomycin-induced pulmonary fibrosis. We performed histological examinations and quantitative measurements of IL-6, TGF-?1, collagen type I?1 and angiopoietin-1 in bleomycin-treated mouse lung tissues with or without the administration of Calpeptin. Calpeptin histologically ameliorated bleomycin-induced pulmonary fibrosis in mice. Calpeptin decreased the expression of IL-6, TGF-?1, angiopoietin-1 and collagen type I?1 mRNA in mouse lung tissues. In vitro studies disclosed that Calpeptin reduced (i) production of IL-6, TGF-?1, angiopoietin-1 and collagen synthesis from lung fibroblasts; and (ii) both IL-6-dependent proliferation and angiopoietin-1-dependent migration of the cells, which could be the mechanism underlying the preventive effect of Calpeptin on pulmonary fibrosis. These data suggest the clinical use of Calpeptin for the prevention of pulmonary fibrosis. PMID:20846163

  19. Statins meditate anti-atherosclerotic action in smooth muscle cells by peroxisome proliferator-activated receptor-γ activation

    SciTech Connect

    Fukuda, Kazuki; Matsumura, Takeshi; Senokuchi, Takafumi; Ishii, Norio; Kinoshita, Hiroyuki; Yamada, Sarie; Murakami, Saiko; Nakao, Saya; Motoshima, Hiroyuki; Kondo, Tatsuya; Kukidome, Daisuke; Kawasaki, Shuji; Kawada, Teruo; Nishikawa, Takeshi; Araki, Eiichi

    2015-01-30

    Highlights: • Statins induce PPARγ activation in vascular smooth muscle cells. • Statin-induced PPARγ activation is mediated by COX-2 expression. • Statins suppress cell migration and proliferation in vascular smooth muscle cells. • Statins inhibit LPS-induced inflammatory responses by PPARγ activation. • Fluvastatin suppress the progression of atherosclerosis and induces PPARγ activation in the aorta of apoE-deficient mice. - Abstract: The peroxisome proliferator-activated receptor-γ (PPARγ) is an important regulator of lipid and glucose metabolism, and its activation is reported to suppress the progression of atherosclerosis. We have reported that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) activate PPARγ in macrophages. However, it is not yet known whether statins activate PPARγ in other vascular cells. In the present study, we investigated whether statins activate PPARγ in smooth muscle cells (SMCs) and endothelial cells (ECs) and thus mediate anti-atherosclerotic effects. Human aortic SMCs (HASMCs) and human umbilical vein ECs (HUVECs) were used in this study. Fluvastatin and pitavastatin activated PPARγ in HASMCs, but not in HUVECs. Statins induced cyclooxygenase-2 (COX-2) expression in HASMCs, but not in HUVECs. Moreover, treatment with COX-2-siRNA abrogated statin-mediated PPARγ activation in HASMCs. Statins suppressed migration and proliferation of HASMCs, and inhibited lipopolysaccharide-induced expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in HASMCs. These effects of statins were abrogated by treatment with PPARγ-siRNA. Treatment with statins suppressed atherosclerotic lesion formation in Apoe{sup −/−} mice. In addition, transcriptional activity of PPARγ and CD36 expression were increased, and the expression of MCP-1 and TNF-α was decreased, in the aorta of statin-treated Apoe{sup −/−} mice. In conclusion, statins mediate anti-atherogenic effects through PPARγ activation in SMCs. These effects of statins on SMCs may be beneficial for the prevention of atherosclerosis.

  20. A Comparative Study of the Aneugenic and Polyploidy-inducing Effects of Fisetin and Two Model Aurora Kinase Inhibitors

    PubMed Central

    Gollapudi, P.; Hasegawa, L.S.; Eastmond, D.A.

    2014-01-01

    Fisetin, a plant flavonol commonly found in fruits, nuts and vegetables, is frequently added to nutritional supplements due to its reported cardioprotective, anti-carcinogenic and antioxidant properties. Earlier reports from our laboratory and others have indicated that fisetin has both aneugenic and clastogenic properties in cultured cells. More recently, fisetin has also been reported to target Aurora B kinase, a Ser/Thr kinase involved in ensuring proper microtubule attachment at the spindle assembly checkpoint, and an enzyme that is overexpressed in several types of cancer. Here we have further characterized the chromosome damage caused by fisetin and compared it with that induced by two known Aurora kinase inhibitors, VX-680 and ZM-447439, in cultured TK6 cells using the micronucleus assay with CREST staining as well as a flow cytometry-based assay that measures multiple types of numerical chromosomal aberrations. The three compounds were highly effective in inducing aneuploidy and polyploidy as evidenced by increases in kinetochore-positive micronuclei, hyperdiploidy, and polyploidy. With fisetin, however, the latter two effects were most significantly observed only after cells were allowed to overcome a cell cycle delay, and occurred at higher concentrations than those induced by the other Aurora kinase inhibitors. Modest increases in kinetochore-negative micronuclei were also seen with the model Aurora kinase inhibitors. These results indicate that fisetin induces multiple types of chromosome abnormalities in human cells, and indicate a need for a thorough investigation of fisetin-augmented dietary supplements. PMID:24680981

  1. Mechanisms of G1 cell cycle arrest and apoptosis in myeloma cells induced by hybrid-compound histone deacetylase inhibitor

    SciTech Connect

    Fujii, Seiko; Division of Maxillofacial Surgery, Kyushu Dental University ; Okinaga, Toshinori; Ariyoshi, Wataru; Oral Biology Research Center, Kyushu Dental University ; Takahashi, Osamu; Iwanaga, Kenjiro; Nishino, Norikazu; Tominaga, Kazuhiro; Nishihara, Tatsuji; Oral Biology Research Center, Kyushu Dental University

    2013-05-10

    Highlights: •Novel histone deacetylase inhibitor Ky-2, remarkably inhibits myeloma cell growth. •Ky-2 demonstrates no cytotoxicity against normal lymphocytic cells. •Ky-2 induces cell cycle arrest through the cell cycle-associated proteins. •Ky-2 induces Bcl-2-inhibitable apoptosis through a caspase-dependent cascade. -- Abstract: Objectives: Histone deacetylase (HDAC) inhibitors are new therapeutic agents, used to treat various types of malignant cancers. In the present study, we investigated the effects of Ky-2, a hybrid-compound HDAC inhibitor, on the growth of mouse myeloma cells. Materials and methods: Myeloma cells, HS-72, P3U1, and mouse normal cells were used in this study. Effect of HDAC inhibitors on cell viability was determined by WST-assay and trypan blue assay. Cell cycle was analyzed using flow cytometer. The expression of cell cycle regulatory and the apoptosis associated proteins were examined by Western blot analysis. Hoechst’s staining was used to detect apoptotic cells. Results: Our findings showed that Ky-2 decreased the levels of HDACs, while it enhanced acetylation of histone H3. Myeloma cell proliferation was inhibited by Ky-2 treatment. Interestingly, Ky-2 had no cytotoxic effects on mouse normal cells. Ky-2 treatment induced G1-phase cell cycle arrest and accumulation of a sub-G1 phase population, while Western blotting analysis revealed that expressions of the cell cycle-associated proteins were up-regulated. Also, Ky-2 enhanced the cleavage of caspase-9 and -3 in myeloma cells, followed by DNA fragmentation. In addition, Ky-2 was not found to induce apoptosis in bcl-2 overexpressing myeloma cells. Conclusion: These findings suggest that Ky-2 induces apoptosis via a caspase-dependent cascade and Bcl-2-inhibitable mechanism in myeloma cells.

  2. Histone deacetylase inhibitors are potent inducers of gene expression in latent EBV and sensitize lymphoma cells to nucleoside antiviral agents.

    PubMed

    Ghosh, Sajal K; Perrine, Susan P; Williams, Robert M; Faller, Douglas V

    2012-01-26

    Induction of EBV lytic-phase gene expression, combined with exposure to an antiherpes viral drug, represents a promising targeted therapeutic approach to EBV-associated lymphomas. Short-chain fatty acids or certain chemotherapeutics have been used to induce EBV lytic-phase gene expression in cultured cells and mouse models, but these studies generally have not translated into clinical application. The recent success of a clinical trial with the pan-histone deacetylase (pan-HDAC) inhibitor arginine butyrate and the antiherpes viral drug ganciclovir in the treatment of EBV lymphomas prompted us to investigate the potential of several HDAC inhibitors, including some new, highly potent compounds, to sensitize EBV(+) human lymphoma cells to antiviral agents in vitro. Our study included short-chain fatty acids (sodium butyrate and valproic acid); hydroxamic acids (oxamflatin, Scriptaid, suberoyl anilide hydroxamic acid, panobinostat [LBH589], and belinostat [PXD101]); the benzamide MS275; the cyclic tetrapeptide apicidin; and the recently discovered HDAC inhibitor largazole. With the exception of suberoyl anilide hydroxamic acid and PXD101, all of the other HDAC inhibitors effectively sensitized EBV(+) lymphoma cells to ganciclovir. LBH589, MS275, and largazole were effective at nanomolar concentrations and were 10(4) to 10(5) times more potent than butyrate. The effectiveness and potency of these HDAC inhibitors make them potentially applicable as sensitizers to antivirals for the treatment of EBV-associated lymphomas. PMID:22160379

  3. Peroxisomal D-bifunctional protein deficiency

    PubMed Central

    Lines, Matthew A.; Jobling, Rebekah; Brady, Lauren; Marshall, Christian R.; Scherer, Stephen W.; Rodriguez, Amadeo R.; Lee, Liesly; Lang, Anthony E.; Mestre, Tiago A.; Wanders, Ronald J.A.; Ferdinandusse, Sacha

    2014-01-01

    Objective: To determine the causative genetic lesion in 3 adult siblings with a slowly progressive, juvenile-onset phenotype comprising cerebellar atrophy and ataxia, intellectual decline, hearing loss, hypogonadism, hyperreflexia, a demyelinating sensorimotor neuropathy, and (in 2 of 3 probands) supratentorial white matter changes, in whom numerous prior investigations were nondiagnostic. Methods: The patients initial clinical assessment included history and physical examination, cranial MRI, and nerve conduction studies. We performed whole-exome sequencing of all 3 probands, followed by variant annotation and selection of rare, shared, recessive coding changes to identify the gene responsible. We next performed a panel of peroxisomal investigations in blood and cultured fibroblasts, including assessment of D-bifunctional protein (DBP) stability and activity by immunoblot and enzymologic methods, respectively. Results: Exome sequencing identified compound heterozygous mutations in HSD17B4, encoding peroxisomal DBP, in all 3 probands. Both identified mutations alter a conserved residue within the active site of DBPs enoyl-CoA hydratase domain. Routine peroxisomal screening tests, including very long-chain fatty acids and phytanic acid, were normal. DBP enzymatic activity was markedly reduced. Conclusion: Exome sequencing provides a powerful and elegant tool in the specific diagnosis of mild or atypical neurometabolic disorders. Given the broad differential diagnosis and the absence of detectable biochemical abnormalities in blood, molecular testing of HSD17B4 should be considered as a first-line investigation in patients with compatible features. PMID:24553428

  4. A Critical Role of the C-terminal Segment for Allosteric Inhibitor-induced Aberrant Multimerization of HIV-1 Integrase*

    PubMed Central

    Shkriabai, Nikoloz; Dharmarajan, Venkatasubramanian; Slaughter, Alison; Kessl, Jacques J.; Larue, Ross C.; Feng, Lei; Fuchs, James R.; Griffin, Patrick R.; Kvaratskhelia, Mamuka

    2014-01-01

    Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are a promising class of antiretroviral agents for clinical development. Although ALLINIs promote aberrant IN multimerization and inhibit IN interaction with its cellular cofactor LEDGF/p75 with comparable potencies in vitro, their primary mechanism of action in infected cells is through inducing aberrant multimerization of IN. Crystal structures have shown that ALLINIs bind at the IN catalytic core domain dimer interface and bridge two interacting subunits. However, how these interactions promote higher-order protein multimerization is not clear. Here, we used mass spectrometry-based protein footprinting to monitor surface topology changes in full-length WT and the drug-resistant A128T mutant INs in the presence of ALLINI-2. These experiments have identified protein-protein interactions that extend beyond the direct inhibitor binding site and which lead to aberrant multimerization of WT but not A128T IN. Specifically, we demonstrate that C-terminal residues Lys-264 and Lys-266 play an important role in the inhibitor induced aberrant multimerization of the WT protein. Our findings provide structural clues for exploiting IN multimerization as a new, attractive therapeutic target and are expected to facilitate development of improved inhibitors. PMID:25118283

  5. Activated peroxisomal fatty acid metabolism improves cardiac recovery in ischemia-reperfusion.

    PubMed

    Liepinsh, Edgars; Skapare, Elina; Kuka, Janis; Makrecka, Marina; Cirule, Helena; Vavers, Edijs; Sevostjanovs, Eduards; Grinberga, Solveiga; Pugovics, Osvalds; Dambrova, Maija

    2013-06-01

    Depressed oxidation of long chain fatty acids (LCFA) in heart ischemia leads to acute accumulation of LCFA metabolites that impair the functioning of the mitochondria. We hypothesized that reduced activity of carnitine palmitoyltransferase-I (CPT-I) might activate peroxisomal LCFA oxidation and protect mitochondrial function in ischemia and reperfusion. In the present study, despite the long-term threefold reduction in L-carnitine content by 3-(2,2,2-trimethylhydrazinium)-propionate, the uptake and oxidation rates of LCFA in the heart in normoxia were not significantly influenced. The significant increase in PPAR? and PGC1? nuclear content, observed in this study, were followed by increased expression of genes involved in peroxisomal fatty acid oxidation (FAO) which compensated for the limited CPT-I-dependent FA transport into the mitochondria. In ischemia followed by reperfusion, the redirection of LCFA oxidation from mitochondria to peroxisomes protected the mitochondria from the accumulation of LCFA. In turn, the recovery of FAO resulted in significant reduction of myocardial infarct size. In conclusion, the decreased L-carnitine content in the heart preserves its peroxisomal and mitochondrial function after ischemia and improves cardiac recovery during reperfusion. The functional interplay between the decrease in L-carnitine and the PPAR?/PGC1? pathway-induced redirection of FA metabolism protects the mitochondria against LCFA overload and provides a foundation for novel cardioprotective mechanisms. PMID:23525500

  6. [Possible participation of mitochondria in formation of peroxisomes in yeasts].

    PubMed

    Kozlova, T M; Me?sel', M N

    1976-01-01

    The origin of peroxisomes in yeast organisms is still unknown. These organelles are believed to be formed, similar to animal cells, from the endoplasmatic reticulum. However, this has not been confirmed directly. Peroxisomes are often found to be in contact with channels of the endoplasmatic reticulum and, in our experiments, with mitochondria of yeast organisms, especially those which utilize oleic acid, n-alkanes and methanol as a sole source of carbon. In Rhodotorula, peroxisomes are characterized by the same "bean" configuration and paired arrangement imitating "copulation" as mitocondria. In Kloeckera boidinii, a mitochondrion was transformed into a peroxisome and cristae were lost. A part of the peroxisome still possessed a double membrane typical of mitochondria while another part had a single membrane characteristic of peroxisomes. Further studies are being carried out in order to find if this is a general relationship or one of possibilities. PMID:1034867

  7. Organic cadmium complexes as proteasome inhibitors and apoptosis inducers in human breast cancer cells

    PubMed Central

    Zhang, Zhen; Bi, Caifeng; Buac, Daniela; Fan, Yuhua; Zhang, Xia; Zuo, Jian; Zhang, Pengfei; Zhang, Nan; Dong, Lili; Dou, Q. Ping

    2013-01-01

    Although cadmium (Cd) is a widespread environmental contaminant and human carcinogen, our studies indicate an organic Cd complex to be a potent inhibitor of proteasomal chymotrypsin-like (CT-like) activity, further capable of inducing apoptosis in a cancer cell-specific manner. It has been reported that the ligands indole-3-butyric acid (L1) and indole-3-propionic acid (L2) have cancer-fighting effects when tested in a rat carcinoma model. In addition, 3, 5-diaminobenzoic acid o-vanillin Schiff bases (L3) have high antimicrobial activity and a large number of Schiff base complexes have been reported to have proteasome-inhibitory activity. We therefore hypothesized that synthetic forms of Cd in combination with L1, L2 and L3 may have proteasome-inhibitory and apoptosis-inducing activities, which would be cancer cell-specific. To test this hypothesis, we have synthesized three novel Cd-containing complexes: [Cd2(C12H12O2N)4(H2O)2]2H2O (Cd1), [Cd2(C11H10O2N)4(H2O)2]2H2O (Cd2) and [Cd(C7H4N2O2)(C8H6O2)2]2H2O (Cd3), by using these three ligands. We sought out to characterize and assess the proteasome-inhibitory and anti-proliferative properties of these three Cd complexes in human breast cancer cells. Cd1, Cd2 and Cd3 were found to effectively inhibit the chymotrypsin-like activity of purified 20S proteasome with IC50 values of 2.6, 3.0 and 3.3 ?M, respectively. Moreover, inhibition of cancer cell proliferation also correlated with this effect. As a result of proteasomal shutdown, the accumulation of ubiquitinated proteins and the proteasome target I?B-? protein as well as induction of apoptosis were observed. To account for the cancer specificity of this effect, immortalized, non-tumorigenic breast MCF10A cells were used under the same experimental conditions. Our results indicate that MCF10A cells are much less sensitive to the Cd1, Cd2 and Cd3 complexes when compared to MDA MB 231 breast cancer cells. Therefore, our study suggests that these Cd organic complexes are capable of inhibiting tumor cellular proteasome activity and consequently induce cancer cell-specific apoptotic death. PMID:23499788

  8. A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

    SciTech Connect

    Park, So Jung; Park, Young Jun; Shin, Ji Hyun; Kim, Eun Sung; Hwang, Jung Jin; Jin, Dong-Hoon; Kim, Jin Cheon; Cho, Dong-Hyung

    2011-05-13

    Highlights: {yields} We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. {yields} Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. {yields} Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. {yields} Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactive chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.

  9. Network-level effects of kinase inhibitors modulate TNF-α-induced apoptosis in the intestinal epithelium

    PubMed Central

    Lau, Ken S.; Lin, Yi-Jang; Genetti, Casie; Samatar, Ahmed A.; Lauffenburger, Douglas A.; Haigis, Kevin M.

    2016-01-01

    Individual signaling pathways are not isolated, but rather operate in the context of the broader signaling network. Thus, the response of a cell to perturbation of a given pathway depends on the state of the network, which depends upon contextual inputs from the microenvironment. The cytokine tumor necrosis factor α (TNF-α) promotes opposing cellular behaviors under different conditions, which is influenced by perturbation of the network. For example, inhibition of the mitogen-activated protein kinase (MAPK) kinase MEK alters the kinetics of TNF-α-induced apoptosis in the mouse intestinal epithelium. We investigated whether MAPK signaling directly influences TNF-α-induced apoptosis, or whether network-level effects secondary to inhibition of the MAPK pathway alter the kinetics of cell death. We found that inhibitors of the MAPK kinase kinase Raf, MEK, and extracellular signal regulated kinase (ERK) exerted distinct effects on the timing and magnitude of TNF-α-induced apoptosis in the mouse intestine. Furthermore, even different MEK inhibitors exerted distinct effects; one of them, CH5126766, potentiated TNF-α-induced apoptosis. Computational modeling analysis and experimental perturbation identified the kinase Akt as the primary signaling node that promoted apoptosis in the context of TNF-α signaling in the presence of CH5126766. Our work emphasizes the importance of integrated network signaling in specifying cellular behavior in response to external perturbation. More broadly, this study highlights the importance of considering the network-level effects of pathway inhibitors and demonstrates the distinct effects of inhibitors that share the same target. PMID:26671150

  10. The MAO-B inhibitor deprenyl reduces the oral tremor and the dopamine depletion induced by the VMAT-2 inhibitor tetrabenazine.

    PubMed

    Podurgiel, Samantha J; Yohn, Samantha E; Dortche, Kristina; Correa, Merce; Salamone, John D

    2016-02-01

    Tetrabenazine (TBZ) is prescribed for the treatment of chorea associated with Huntington's disease. Via inhibition of the vesicular monoamine transporter (VMAT-2), TBZ blocks dopamine (DA) storage and depletes striatal DA; this drug also has been shown to induce Parkinsonian motor side effects in patients. Recently, TBZ was shown to induce tremulous jaw movements (TJMs) in rats and mice. TJMs are an oral tremor that has many of the characteristics of Parkinsonian tremor in humans. The present study focused upon the ability of the well-estabilished antiparkinsonian agent deprenyl to attenuate the behavioral and neurochemical effects of 2.0mg/kg TBZ. Deprenyl is a selective and irreversible inhibitor of monoamine oxidase-B, and administration of deprenyl produced a dose-related suppression of TBZ-induced TJMs. A second experiment employed in vivo microdialysis to examine extracellular DA levels in the ventrolateral striatum, the neostriatal region most closely associated with the production of TJMs, after administration of TBZ and deprenyl. Consistent with the behavioral data, TBZ alone produced a biphasic effect on extracellular DA, with an initial increases followed by a prolonged decrease during the period in which TJMs are displayed. Co-administration of deprenyl with TBZ increased DA levels compared to rats treated with TBZ alone. These results provide support for use of TBZ as a rodent model of Parkinsonism, and future studies should utilize this model to evaluate putative anti-Parkinsonian agents. PMID:26590367

  11. De novo peroxisome biogenesis: Evolving concepts and conundrums.

    PubMed

    Agrawal, Gaurav; Subramani, Suresh

    2016-05-01

    Peroxisomes proliferate by growth and division of pre-existing peroxisomes or could arise de novo. Though the de novo pathway of peroxisome biogenesis is a more recent discovery, several studies have highlighted key mechanistic details of the pathway. The endoplasmic reticulum (ER) is the primary source of lipids and proteins for the newly-formed peroxisomes. More recently, an intricate sorting process functioning at the ER has been proposed, that segregates specific PMPs first to peroxisome-specific ER domains (pER) and then assembles PMPs selectively into distinct pre-peroxisomal vesicles (ppVs) that later fuse to form import-competent peroxisomes. In addition, plausible roles of the three key peroxins Pex3, Pex16 and Pex19, which are also central to the growth and division pathway, have been suggested in the de novo process. In this review, we discuss key developments and highlight the unexplored avenues in de novo peroxisome biogenesis. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26381541

  12. Ultrastructural and cytochemical identification of peroxisomes in Balantidium coli, Ciliophora.

    PubMed

    Skotarczak, B

    1997-01-01

    Peroxisomes of the trophozoites of Balantidium coli isolated from pig intestine content were investigated, using ultrastructural and cytochemical techniques. The peroxisomes of B. coli trophozoites from pigs with subclinical balantidiasis are less then 0.8 mm in diameter whereas those from pigs with acute balantidiasis are greater than 0.8 micron in diameter. In all the trophozoites peroxisomes are round, oval or dumb-bell shaped. Catalase as an indicative enzyme was detected by cytochemical techniques in B. coli peroxisomes. PMID:9643167

  13. Emerging role of the endoplasmic reticulum in peroxisome biogenesis