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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. Inhibitors of Growth 1b Suppresses Peroxisome Proliferator-Activated Receptor-β/δ Expression Through Downregulation of Hypoxia-Inducible Factor 1α in Osteoblast Differentiation.

    PubMed

    Qu, Bo; Hong, Zhen; Gong, Kai; Sheng, Jun; Wu, Hong-Hua; Deng, Shao-Lin; Huang, Gang; Ma, Ze-Hui; Pan, Xian-Ming

    2016-04-01

    Bone formation, a highly regulated developmental process, involves osteoblast differentiation, which is controlled by different important transcription factors. Recent evidence has suggested possible negative regulation of inhibitors of growth (ING) 1b on the osteoblast marker expression. The aim of this study is to examine the detailed mechanism by which the activity of ING1b inhibits osteoblast differentiation. In the current study, we investigated the function and mechanism by which ING1b inhibits osteoblast differentiation using C3H10T1/2 mesenchymal stem cells and MC3T3-E1 preosteoblasts. Real-time polymerase chain reaction and Western blotting showed that ING1b was decreased during osteoblast differentiation and ING1b overexpression markedly decreased alkaline phosphatase (ALP) activity, runt-related transcription factor 2 (Runx2) expression, and collagen type 1 synthesis, whereas ING1b silencing significantly upregulated ALP activity, Runx2 expression, and collagen type 1 synthesis. Further studies indicated that ING1b suppressed the expression of peroxisome proliferator-activated receptor (PPAR)-β/δ in a hypoxia-inducible factor (HIF) 1α-dependent manner, while ING1b silencing significantly increased the expression of PPAR-β/δ and HIF1α. Moreover, PPAR-β/δ or HIF1α silencing significantly inhibited ALP activity, Runx2 expression, and collagen type 1 synthesis. These results demonstrated that ING1b is an important regulator of osteoblast differentiation and suppresses PPAR-β/δ. Our study may provide additional insight into osteoblast differentiation and offer a potential new molecular target for osteoporosis. PMID:26849833

  3. NADH induces the generation of superoxide radicals in leaf peroxisomes. [Pisum sativum L

    SciTech Connect

    del Rio, L.A.; Sandalio, L.M.; Palma, J.M. ); Fernandez, V.M.; Ruperez, F.L. )

    1989-03-01

    In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O{sub 2}{sup {minus}}) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O{sub 2}{sup {minus}} radicals. In the soluble fractions of peroxisomes, no generation of O{sub 2}{sup {minus}} radicals was observed by incubation with either NADH or xanthine, although xanthine oxidase was found located predominantly in the matrix of peroxisomes. The failure of xanthine to induce superoxide generation was probably due to the inability to fully suppress the endogenous Mn-superoxide dismutase activity by inhibitors which were inactive against xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes suggests that O{sub 2}{sup {minus}} generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related roles for peroxisomes in cellular metabolism.

  4. 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.

  5. 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

  6. 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 β-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

  7. 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, 109–120. PMID:25226217

  8. Psychosine-induced alterations in peroxisomes of Twitcher Mouse Liver

    PubMed Central

    Contreras, Miguel Agustin; Haq, Ehtishamul; Uto, Takuhiro; Singh, Inderjit; Singh, Avtar Kaur

    2008-01-01

    Krabbe’s disease is a neuroinflammatory disorder in which galactosylsphingosine (psychosine) accumulates in nervous tissue. To gain insight into whether the psychosine-induced effects in nervous tissue extend to peripheral organs, we investigated the expression of cytokines and their effects on peroxisomal structure/function in twitcher mouse liver (animal model of Krabbe disease). Immunofluorescence analysis demonstrated TNF-α and IL-6 expression, which was confirmed by mRNAs quantitation. Despite the presence of TNF-α, lipidomic analysis did not indicate a significant decrease in sphingomyelin or an increase in ceramide fractions. Ultrastructural analysis of catalase-dependent staining of liver sections showed reduced reactivity without significant changes in peroxisomal contents. This observation was confirmed by assaying catalase activity and quantitation of its mRNA, both of which were found significantly decreased in twitcher mouse liver. Western blot analysis demonstrated a generalized reduction of peroxisomal matrix and membrane proteins. These observations indicate that twitcher mouse pathobiology extends to the liver, where the induction of TNF-α and IL-6 compromise peroxisomal structure and function. PMID:18602885

  9. PPARα Activation Induces Nε-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 PPARα-agonist treated rat liver screened with an anti-Nε-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 PPARα-dependent proliferation of peroxisomes in rat liver. PMID:24092543

  10. Peroxisome Proliferator-Activated Receptorα Agonists Differentially Regulate Inhibitor of DNA Binding Expression in Rodents and Human Cells

    PubMed Central

    González, María del Carmen; Corton, J. Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Álvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans. PMID:22701468

  11. Peroxisome proliferator-activated receptorα agonists differentially regulate inhibitor of DNA binding expression in rodents and human cells.

    PubMed

    González, María Del Carmen; Corton, J Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Alvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans. PMID:22701468

  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. Peroxisomes and Kidney Injury

    PubMed Central

    2016-01-01

    Abstract Significance: Peroxisomes are organelles present in most eukaryotic cells. The organs with the highest density of peroxisomes are the liver and kidneys. Peroxisomes possess more than fifty enzymes and fulfill a multitude of biological tasks. They actively participate in apoptosis, innate immunity, and inflammation. In recent years, a considerable amount of evidence has been collected to support the involvement of peroxisomes in the pathogenesis of kidney injury. Recent Advances: The nature of the two most important peroxisomal tasks, beta-oxidation of fatty acids and hydrogen peroxide turnover, functionally relates peroxisomes to mitochondria. Further support for their communication and cooperation is furnished by the evidence that both organelles share the components of their division machinery. Until recently, the majority of studies on the molecular mechanisms of kidney injury focused primarily on mitochondria and neglected peroxisomes. Critical Issues: The aim of this concise review is to introduce the reader to the field of peroxisome biology and to provide an overview of the evidence about the contribution of peroxisomes to the development and progression of kidney injury. The topics of renal ischemia–reperfusion injury, endotoxin-induced kidney injury, diabetic nephropathy, and tubulointerstitial fibrosis, as well as the potential therapeutic implications of peroxisome activation, are addressed in this review. Future Directions: Despite recent progress, further studies are needed to elucidate the molecular mechanisms induced by dysfunctional peroxisomes and the role of the dysregulated mitochondria–peroxisome axis in the pathogenesis of renal injury. Antioxid. Redox Signal. 25, 217–231. PMID:26972522

  14. 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.

  15. Kupffer cells suppress perfluorononanoic acid-induced hepatic peroxisome proliferator-activated receptor α expression by releasing cytokines.

    PubMed

    Fang, Xuemei; Zou, Shanshan; Zhao, Yuanyuan; Cui, Ruina; Zhang, Wei; Hu, Jiayue; Dai, Jiayin

    2012-10-01

    Kupffer cells (KCs) have been demonstrated to play a role in the regulation of intra-hepatic lipid metabolism through the synthesis and secretion of biologically active products. The involvement of KCs in the disturbance of lipid metabolism that induced by perfluorononanoic acid (PFNA), a known agonist of the peroxisome proliferator-activated receptor alpha (PPARα), was investigated in this study. Rats were exposed to PFNA or PFNA combined with gadolinium chloride, an inhibitor of KCs, for 14 days. PFNA exposure dose-dependently increased absolute and relative liver weights, induced triglyceride accumulation, up-regulated the expression of both SERBP-1c and PPARα, and stimulated the release of TNFα and IL-1β. Inactivation of KCs markedly lowered TNFα and IL-1β level, enhanced PFNA-induced expression of PPARα and its target genes, and reduced liver triglyceride levels. In vitro, PFNA-induced expression of PPARα in primary cultured hepatocytes was suppressed by recombinant rat TNFα and IL-1β. However, inhibition of the NF-κB pathway prevented this. Transient transfection and promoter analysis further revealed that these two cytokines and NF-κB were coordinately involved in the suppression of PPARα promoter activity. Our data demonstrate that TNFα and IL-1β released from KCs following PFNA exposure can suppress the expression of PPARα via NF-κB pathway, which partially contribute to the evident accumulation of triglycerides in rat liver. PMID:22648072

  16. 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}.

  17. Peroxisome proliferator activated receptor gamma is not necessary for the development of LPS-induced tolerance in macrophages.

    PubMed

    Zingarelli, Basilia; Fan, Hongkuan; Ashton, Sarah; Piraino, Giovanna; Mangeshkar, Prajakta; Cook, James A

    2008-05-01

    Peroxisome proliferator activated receptor-gamma (PPARgamma) has been reported to exert anti-inflammatory properties in endotoxic shock and sepsis. One phenomenon that alters the inflammatory response to endotoxin [lipopolysaccharide (LPS)] is endotoxin tolerance, which is caused by previous exposure to endotoxin. Here, we investigate whether changes in endogenous PPARgamma function regulate this phenomenon using three different models of LPS-induced tolerance in macrophages. In a first in vitro model, previous LPS exposure of murine J774.2 macrophages suppressed tumour necrosis factor-alpha (TNF-alpha) release in response to subsequent LPS challenge. Treatment of J774.2 cells with the PPARgamma inhibitor GW9662 did not alter tolerance induction because these cells were still hyporesponsive to the secondary LPS challenge. In a second ex vivo model, primary rat peritoneal macrophages from LPS-primed rats exhibited suppression of thromboxane B2 and TNF-alpha production, while maintaining nitrite production in response to in vitro LPS challenge. Pretreatment of rats with the PPARgamma inhibitor GW9662 in vivo failed to alter the tolerant phenotype of these primary macrophages. In a third ex vivo model, primary peritoneal macrophages with conditional deletion of PPARgamma were harvested from LPS-primed Cre-lox mice (Cre+/+ PPARgamma-/-) and exhibited significant suppression of TNF-alpha production in response to in vitro LPS challenge. Furthermore, both LPS-primed PPARgamma-deficient Cre+/+ PPARgamma-/- mice and wild-type Cre-/- PPARgamma+/+ mice exhibited reduced plasma TNF-alpha levels in response to a high dose of LPS in vivo. These data demonstrate that PPARgamma does not play a role in the LPS-induced tolerant phenotype in macrophages. PMID:18028370

  18. Peroxisome proliferator-activated receptor gamma ligands induce growth inhibition and apoptosis of human B lymphocytic leukemia.

    PubMed

    Zang, Chuanbing; Liu, Hongyu; Posch, Maximilian G; Waechter, Maries; Facklam, Margit; Fenner, Martin H; Ruthardt, Martin; Possinger, Kurt; Phillip Koeffler, H; Elstner, Elena

    2004-04-01

    This study examined the expression and structural intactness of peroxisome proliferator-activated receptor gamma (PPARgamma) in human acute lymphocytic leukemia (ALL) cells and determined the effect of PPARgamma ligands on growth and apoptosis of these cells. We noted that all lymphocytic leukemia cell lines expressed PPARgamma and no PPARgamma mutations were found in these cell lines as indicated by SSCP analysis. Effect of the PPARgamma ligands on the proliferation, differentiation and apoptosis of B type ALL cells was further examined. Treatment of these cells with the PPARgamma ligands Pioglitazone (PGZ) and 15-deoxy-delta (12,14)-prostaglandin J2 (15d-PGJ2) resulted in growth inhibition in a dose-dependent manner which was associated with a G1 to S cell cycle arrest. However, this effect appeared to be PPARgamma-independent since several PPARgamma antagonists could not reverse this effect. No differentiation was induced by this treatment. Four out of five cell lines underwent apoptosis after culture with the PPARgamma ligands. This effect was partially caspase-dependent because a pan-caspase inhibitor partially reversed this effect. In conclusion, our results suggest that PPARgamma ligands may offer a new therapeutic approach to aid in the treatment of ALL. PMID:15109539

  19. Rat 17 beta-hydroxysteroid dehydrogenase type IV is a novel peroxisome proliferator-inducible gene.

    PubMed

    Corton, J C; Bocos, C; Moreno, E S; Merritt, A; Marsman, D S; Sausen, P J; Cattley, R C; Gustafsson, J A

    1996-11-01

    To better understand the molecular mechanisms of the pleiotropic responses induced by exposure to peroxisome proliferator chemicals (PPCs), we conducted a systematic search for genes whose mRNA levels are modulated by the PPC WY-14,643 (WY) in rat liver. The sequence of one up-regulated cDNA (2480 bp) was predicted to encode a protein of 735 aa with 82% identity to the porcine 17 beta-hydroxysteroid dehydrogenase type IV (HSD IV). Like the porcine enzyme, the rat HSD IV contains' a region homologous to yeast hydratase-dehydrogenase-epimerases and to sterol carrier proteins, indicating that the rat HSD IV has broad substrate specificity and contributes to cholesterol metabolism. The rat HSD IV was regulated by diverse PPCs via two distinct mechanisms. Induction of HSD IV and acyl-CoA oxidase (ACO) proteins in rat liver at different treatment times and concentrations of gemfibrozil and di-n-butyl phthalate were almost identical, indicating that HSD IV mRNA induction involves the peroxisome proliferator-activated receptor alpha, a regulator of ACO. In contrast, HSD IV protein levels were only weakly induced by WY, a strong inducer of ACO protein, even though the levels of HSD IV and ACO mRNA were strongly stimulated by WY and gemfibrozil. Thus, HSD IV protein levels were uniquely regulated pretranslationally by WY via a novel mechanism. Increased conversion of estradiol to the less-active estrone by HSD IV induction may explain how phthalate exposure leads to decreases in serum estradiol levels and suppression of ovulation. PMID:8913347

  20. Chemical synthesis, docking studies and biological effects of a pan peroxisome proliferator-activated receptor agonist and cyclooxygenase inhibitor.

    PubMed

    Santin, José Roberto; Uchôa, Flávia D T; Lima, Maria do Carmo A; Rabello, Marcelo M; Machado, Isabel Daufenback; Hernandes, Marcelo Z; Amato, Angelica A; Milton, Flora Aparecida; Webb, Paul; Neves, Francisco de Assis Rocha; Galdino, Suely L; Pitta, Ivan Rocha; Farsky, Sandra H P

    2013-03-12

    The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase (COX) and also to activate peroxisome proliferator-activated receptor (PPAR). Results obtained from docking (in silico) studies corroborated with experimental data, showing the potential affinity between the studied ligand and targets. The specificity of LYSO-7 for COX-enzymes was detected by the inhibition of COX-1 and COX-2 activities by 30% and 20%, respectively. In transactivation reporter gene assays LYSO-07 showed a pan partial agonist effect on the three PPAR subtypes (PPARγ, PPARα and PPARβ/δ). The agonist action on PPARγ was also observed by a pharmacological approach, as the reduction in the Escherichia coli lipopolysaccharide (LPS)-induced interleukin 1 beta (IL-1β) secretion and nitric oxide (NO) production by mouse neutrophils was blocked by GW9962, a specific PPARγ antagonist. Additionally, the in vivo effect was measured by reduced carrageenan-induced neutrophil influx into the subcutaneous tissue of mice. Taken together, these data show that LYSO-7 displays a potent in vivo anti-inflammatory effect during the innate acute response, which is dependent on its associated COX inhibitory activities and PPAR activation. PMID:23305993

  1. Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone reverses the adverse effects of diet-induced obesity on oocyte quality.

    PubMed

    Minge, Cadence E; Bennett, Brenton D; Norman, Robert J; Robker, Rebecca L

    2008-05-01

    Obesity and its physiological consequences are increasingly prevalent among women of reproductive age and are associated with infertility. To investigate, female mice were fed a high-fat diet until the onset of insulin resistance, followed by assessments of ovarian gene expression, ovulation, fertilization, and oocyte developmental competence. We report defects to ovarian function associated with diet-induced obesity (DIO) that result in poor oocyte quality, subsequently reduced blastocyst survival rates, and abnormal embryonic cellular differentiation. To identify critical cellular mediators of ovarian responses to obesity induced insulin resistance, DIO females were treated for 4 d before mating with an insulin-sensitizing pharmaceutical: glucose and lipid-lowering AMP kinase activator, 5-aminoimidazole 4-carboxamide-riboside, 30 mg/kg.d; sodium salicylate, IkappaK inhibitor that reverses insulin resistance, 50 mg/kg.d; or peroxisome proliferator activated receptor-gamma agonist rosiglitazone, 10 mg/kg.d. 5-aminoimidazole 4-carboxamide-riboside or sodium salicylate treatment did not have significant effects on the reproductive parameters examined. However, embryonic development to the blastocyst stage was significantly improved when DIO mice were treated with rosiglitazone, effectively repairing development rates. Rosiglitazone also normalized DIO-associated abnormal blastomere allocation to the inner cell mass. Such improvements to oocyte quality were coupled with weight loss, improved glucose metabolism, and changes in ovarian mRNA expression of peroxisome proliferator activated receptor-regulated genes, Cd36, Scarb1, and Fabp4 cholesterol transporters. These studies demonstrate that peri-conception treatment with select insulin-sensitizing pharmaceuticals can directly influence ovarian functions and ultimately exert positive effects on oocyte developmental competence. Improved blastocyst quality in obese females treated with rosiglitazone before mating

  2. Peroxisome Proliferator-Activated Receptor γ Regulates Chronic Alcohol-Induced Alveolar Macrophage Dysfunction.

    PubMed

    Yeligar, Samantha M; Mehta, Ashish J; Harris, Frank L; Brown, Lou Ann S; Hart, C Michael

    2016-07-01

    Peroxisome proliferator-activated receptor (PPAR) γ is critical for alveolar macrophage (AM) function. Chronic alcohol abuse causes AM phagocytic dysfunction and susceptibility to respiratory infections by stimulating nicotinamide adenine dinucleotide oxidases (Nox), transforming growth factor-β1, and oxidative stress in the AM. Because PPARγ inhibits Nox expression, we hypothesized that alcohol reduces PPARγ, stimulating AM dysfunction. AMs were examined from: (1) patients with alcoholism or control patients; (2) a mouse model of chronic ethanol consumption; (3) PPARγ knockout mice; or (4) MH-S cells exposed to ethanol in vitro. Alcohol reduced AM PPARγ levels and increased Nox1, -2, and -4, transforming growth factor-β1, oxidative stress, and phagocytic dysfunction. Genetic loss of PPARγ recapitulated, whereas stimulating PPARγ activity attenuated alcohol-mediated alterations in gene expression and phagocytic function, supporting the importance of PPARγ in alcohol-induced AM derangements. Similarly, PPARγ activation in vivo reduced alcohol-mediated impairments in lung bacterial clearance. Alcohol increased levels of microRNA-130a/-301a, which bind to the PPARγ 3' untranslated region to reduce PPARγ expression. MicroRNA-130a/-301a inhibition attenuated alcohol-mediated PPARγ reductions and derangements in AM gene expression and function. Alcohol-induced Toll-like receptor 4 endocytosis was reversed by PPARγ activation. These findings demonstrate that targeting PPARγ provides a novel therapeutic approach for mitigating alcohol-induced AM derangements and susceptibility to lung infection. PMID:26677910

  3. Peroxisome proliferator-activated receptor-gamma ligands inhibit proliferation and induce apoptosis in mantle cell lymphoma.

    PubMed

    Eucker, Jan; Sterz, Jan; Krebbel, Holger; Zavrski, Ivana; Kaiser, Martin; Zang, Chuanbing; Heider, Ulrike; Jakob, Christian; Elstner, Elena; Sezer, Orhan

    2006-08-01

    Peroxisome proliferator-activated receptor-gamma, a nuclear receptor and transcription factor, and its natural and synthetic ligands have become a focus of novel approaches to induction of apoptosis in solid tumors and hematologic malignancies, including malignant B-lineage cells. The effect on mantle cell lymphoma, a subtype with dismal prognosis, has not yet been analyzed. We investigated the effect of 15-deoxy-delta-12,14-prostaglandin J2 (15d-PGJ2), pioglitazone (PGZ) or rosiglitazone (RGZ) on human mantle cell lymphoma cell lines (GRANTA-519, Hbl-2 and JeKo-1). Mantle cell lymphoma cell lines exhibited a high expression of Peroxisome proliferator-activated receptor-gamma protein in Western blot analysis. MTT assays revealed anti-proliferative effects induced by both 15d-PGJ2, the natural activator of Peroxisome proliferator-activated receptor-gamma, and PGZ and RGZ, synthetic Peroxisome proliferator-activated receptor-gamma ligands, in a dose-dependent manner. At a dose of 50 micromol/l, 15d-PGJ2 induced growth inhibition in all cell lines. The anti-proliferative effect of PGZ and RGZ was slightly lower. Induction of apoptosis was indicated by annexin V staining. At a dose of 50 micromol/l, 15d-PGJ2 led to apoptosis in all cell lines (87-99%) after 48 h of incubation. Again, the apoptotic effect with thiazolidinediones was slightly lower at the same dose level. This is the first study evaluating Peroxisome proliferator-activated receptor-gamma expression and its therapeutic implications in human mantle cell lymphoma cells. Thiazolidinediones comprise anti-lymphoma activity in vitro and should be further explored for the treatment of mantle cell lymphoma. PMID:16926626

  4. Peroxisome proliferation-associated control of reactive oxygen species sets melanocortin tone and feeding in diet-induced obesity.

    PubMed

    Diano, Sabrina; Liu, Zhong-Wu; Jeong, Jin Kwon; Dietrich, Marcelo O; Ruan, Hai-Bin; Kim, Esther; Suyama, Shigetomo; Kelly, Kaitlin; Gyengesi, Erika; Arbiser, Jack L; Belsham, Denise D; Sarruf, David A; Schwartz, Michael W; Bennett, Anton M; Shanabrough, Marya; Mobbs, Charles V; Yang, Xiaoyong; Gao, Xiao-Bing; Horvath, Tamas L

    2011-09-01

    Previous studies have proposed roles for hypothalamic reactive oxygen species (ROS) in the modulation of circuit activity of the melanocortin system. Here we show that suppression of ROS diminishes pro-opiomelanocortin (POMC) cell activation and promotes the activity of neuropeptide Y (NPY)- and agouti-related peptide (AgRP)-co-producing (NPY/AgRP) neurons and feeding, whereas ROS-activates POMC neurons and reduces feeding. The levels of ROS in POMC neurons were positively correlated with those of leptin in lean and ob/ob mice, a relationship that was diminished in diet-induced obese (DIO) mice. High-fat feeding resulted in proliferation of peroxisomes and elevated peroxisome proliferator-activated receptor γ (PPAR-γ) mRNA levels within the hypothalamus. The proliferation of peroxisomes in POMC neurons induced by the PPAR-γ agonist rosiglitazone decreased ROS levels and increased food intake in lean mice on high-fat diet. Conversely, the suppression of peroxisome proliferation by the PPAR antagonist GW9662 increased ROS concentrations and c-fos expression in POMC neurons. Also, it reversed high-fat feeding-triggered elevated NPY/AgRP and low POMC neuronal firing, and resulted in decreased feeding of DIO mice. Finally, central administration of ROS alone increased c-fos and phosphorylated signal transducer and activator of transcription 3 (pStat3) expression in POMC neurons and reduced feeding of DIO mice. These observations unmask a previously unknown hypothalamic cellular process associated with peroxisomes and ROS in the central regulation of energy metabolism in states of leptin resistance. PMID:21873987

  5. 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; Song, Seung Ryel; Park, Do-Sim; 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.

  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. Peroxisome proliferator-activated receptor gamma agonists protect cerebellar granule cells from cytokine-induced apoptotic cell death by inhibition of inducible nitric oxide synthase.

    PubMed

    Heneka, M T; Feinstein, D L; Galea, E; Gleichmann, M; Wüllner, U; Klockgether, T

    1999-12-01

    Cerebellar granule cells (CGCs) can express the inducible isoform of nitric oxide synthase (iNOS) in response to inflammatory stimuli. We demonstrate that induction of iNOS in CGCs by bacterial lipopolysaccharide and pro-inflammatory cytokines results in cell death that was potentiated by excess L-arginine and inhibited by the selective iNOS inhibitor, 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine. The NO-mediated cell death was accompanied by increased caspase-3-like activity, DNA fragmentation and positive terminal transferase dUTP nick end labeling (TUNEL), suggesting that apoptosis mediates CGC cell death. Incubation of CGCs with the non-steroidal anti-inflammatory drugs (NSAIDs), ibuprofen or indomethacin, or with 15-deoxy-delta12,14 prostaglandin J2 (PGJ2) downregulates iNOS expression and reduces subsequent cell death. Since in other cell types, both NSAIDs and PGJ2 can activate the peroxisome proliferator-activated receptor-gamma (PPARgamma) and downregulate cytokine levels and iNOS expression, and since CGCs express PPARgamma in vivo and in vitro, our data suggest that activation of CGC PPARgamma mediates iNOS suppression and reduced cell death. Because PPARgamma is expressed in brains of Alzheimer's Disease (AD) patients, in which neuronal iNOS expression and apoptotic cell death have been described, these results may help explain the basis for the beneficial effects of NSAIDs in AD. PMID:10695726

  8. Optical Control of Peroxisomal Trafficking.

    PubMed

    Spiltoir, Jessica I; Strickland, Devin; Glotzer, Michael; Tucker, Chandra L

    2016-07-15

    The blue-light-responsive LOV2 domain of Avena sativa phototropin1 (AsLOV2) has been used to regulate activity and binding of diverse protein targets with light. Here, we used AsLOV2 to photocage a peroxisomal targeting sequence, allowing light regulation of peroxisomal protein import. We generated a protein tag, LOV-PTS1, that can be appended to proteins of interest to direct their import to the peroxisome with light. This method provides a means to inducibly trigger peroxisomal protein trafficking in specific cells at user-defined times. PMID:26513473

  9. Peroxisome Proliferator-Activated Receptor Agonist Treatment of Alcohol-Induced Hepatic Insulin Resistance

    PubMed Central

    de la Monte, Suzanne M.; Pang, Maoyin; Chaudhry, Rajeeve; Duan, Kevin; Longato, Lisa; Carter, Jade; Ouh, Jiyun; Wands, Jack R.

    2011-01-01

    Chronic ethanol exposure impairs insulin signaling in the liver. Peroxisome-proliferator activated receptor (PPAR) agonists function as insulin sensitizers and are used to treat type 2 diabetes mellitus. We examined the therapeutic effectiveness of PPAR agonists in reducing alcoholic hepatitis and hepatic insulin resistance in a model of chronic ethanol feeding. Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% (control) or 37% ethanol (caloric content; 9.2% v/v) for 8 weeks. After 3 weeks on the diets, the rats were treated with vehicle, or a PPAR-α, PPAR-δ, or PPAR-γ agonist twice weekly by i.p. injection. Livers were harvested for histopathological, gene expression (RT-PCR), protein (Western and ELISA), and receptor binding studies. Ethanol-fed rats developed steatohepatitis with disordered hepatic chord architecture, increased hepatocellular apoptosis, reduced binding to the insulin, IGF-1, and IGF-2 receptors, and decreased expression of glyceraldehyde-3-phosphate dehydrogenase and aspartyl-(asparaginyl)-β-hydroxylase (mediates remodeling), which are regulated by insulin/IGF signaling. PPAR-α, PPAR-δ, or PPAR-γ agonist treatments reduced the severity of ethanol-mediated liver injury, including hepatic architectural disarray and steatosis. In addition, PPAR-δ and PPAR-γ agonists reduced insulin/IGF resistance and increased insulin/IGF-responsive gene expression. In conclusion, PPAR agonists may help reduce the severity of chronic ethanol-induced liver injury and insulin/IGF resistance, even in the context of continued high-level ethanol consumption. PMID:21426453

  10. Troglitazone regulates peroxisome proliferator-activated receptors and inducible nitric oxide synthase in murine ovarian macrophages.

    PubMed

    Minge, Cadence E; Ryan, Natalie K; Van Der Hoek, Kylie H; Robker, Rebecca L; Norman, Robert J

    2006-01-01

    Peroxisome proliferator-activated receptor-gamma (PPARG) and PPAR-alpha (PPARA) control metabolic processes in many cell types and act as anti-inflammatory regulators in macrophages. PPAR-activating ligands include thiazolidinediones (TZDs), such as troglitazone, once frequently used to treat insulin resistance as well as symptoms of polycystic ovary syndrome (PCOS). Since macrophages within the ovary mediate optimal follicle development, TZD actions to improve PCOS symptoms are likely to be partly mediated through these specifically localized immune cells. In mouse ovary, PPARG protein was expressed in granulosa cells and in isolated cells localized to theca, stroma, and corpora lutea, consistent with EMR1+ macrophages. Isolation of immune cells (EMR1+ or H2+) showed that Pparg and Ppara were expressed in ovarian macrophages at much higher levels than in peritoneal macrophages. Ovulatory human chorionic gonadotropin downregulated expression of Pparg and Ppara in EMR1+ ovarian macrophages, but no hormonal responsiveness was observed in H2+ cells. Downstream anti-inflammatory effects of PPARG activation were analyzed by in vitro treatment of isolated macrophages with troglitazone. Interleukin-1 beta (Il1b) expression was not altered, and tumor necrosis factor-alpha (Tnf) expression was affected in peritoneal macrophages only. In ovarian macrophages, inducible nitric oxide synthase (Nos2), an important proinflammatory enzyme that regulates ovulation, was significantly reduced by troglitazone treatment, an effect that was restricted to cells from the preovulatory ovary. Thus, expression of PPARs within ovarian macrophages is hormonally regulated, reflecting the changing roles of these cells during the ovulatory cycle. Additionally, ovarian macrophages respond directly to troglitazone to downregulate expression of proinflammatory Nos2, providing mechanistic information about ovarian effects of TZD treatment. PMID:16192401

  11. Peroxisome Proliferator–Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na+/H+ Exchanger NHE1

    PubMed Central

    Chen, Cheng-Hsien; Chen, Tso-Hsiao; Wu, Mei-Yi; Chen, Jia-Rung; Hong, Li-Yu; Zheng, Cai-Mei; Chiu, I-Jen; Lin, Yuh-Feng; Hsu, Yung-Ho

    2015-01-01

    Peroxisome proliferator–activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na+/H+ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na+/H+ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin. PMID:26623927

  12. Liver fatty acid-binding protein: specific mediator of the mitogenesis induced by two classes of carcinogenic peroxisome proliferators.

    PubMed Central

    Khan, S H; Sorof, S

    1994-01-01

    Peroxisome proliferators (PP) are a diverse group of chemicals that induce dramatic increases in peroxisomes in rodent hepatocytes, followed by hypertrophy, hepatomegaly, alterations in lipid metabolism, mitogenesis, and finally hepatocarcinomas. Termed nongenotoxic carcinogens, they do not interact with DNA, are not mutagenic in bacterial assays, and fail to elicit many of the phenotypes associated with classic genotoxic carcinogens. We report here that the mitogenesis induced by the major PP class, the amphipathic carboxylates, and by the tetrazole-substituted acetophenones specifically requires liver fatty acid-binding protein (L-FABP) in cultured rat hepatoma cells transfected with the sense cDNA of L-FABP, in contrast to L-FABP-nonexpressing cells transfected with its antisense cDNA. The mitogenic actions of L-FABP were protein-specific, inasmuch as no other protein in the nonexpressing cells could act like L-FABP. L-FABP was previously shown not only (i) to interact covalently with metabolites of the two genotoxic carcinogens 2-acetylaminofluorene and aminoazo dyes during liver carcinogenesis, but also (ii) to bind noncovalently the two classes of PP in vitro with avidities that correlate with their abilities to elicit peroxisomal enzymatic responses, and (iii) together with unsaturated fatty acids, especially linoleic acid, to promote multiplication of the transfected hepatoma cells in culture. The convergence of the two types of genotoxic carcinogens with the two classes of PP nongenotoxic carcinogens, and also with unsaturated fatty acids, at L-FABP actions in inducing mitogenesis allows the following hypothesis. During tumor promotion of carcinogenesis in vivo, these groups of genotoxic and nongenotoxic carcinogens act on the normal process by which L-FABP, functioning as a specific receptor of unsaturated fatty acids or their metabolites, promotes hepatocyte proliferation. Images PMID:8302856

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

    PubMed Central

    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 3β,7β-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) γ activation. Luciferase reporter assays indicated the ability of DMC to activate PPARγ, and pharmacological inhibition of PPARγ protected cells from DMC's antiproliferative effect. Western blot analysis indicated that DMC suppressed the expression of many PPARγ-targeted signaling effectors, including cyclin D1, CDK6, Bcl-2, XIAP, cyclooxygenase-2, NF-κB, and estrogen receptor α, 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 PPARγ-targeted signaling pathways provides a mechanistic basis to account for the antitumor activity of wild bitter gourd. PMID:23843889

  14. Cucurbitane Triterpenoid from Momordica charantia Induces Apoptosis and Autophagy in Breast Cancer Cells, in Part, through Peroxisome Proliferator-Activated Receptor γ 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 β ,7 β -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) γ activation. Luciferase reporter assays indicated the ability of DMC to activate PPAR γ , and pharmacological inhibition of PPAR γ protected cells from DMC's antiproliferative effect. Western blot analysis indicated that DMC suppressed the expression of many PPAR γ -targeted signaling effectors, including cyclin D1, CDK6, Bcl-2, XIAP, cyclooxygenase-2, NF- κ B, and estrogen receptor α , 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 γ -targeted signaling pathways provides a mechanistic basis to account for the antitumor activity of wild bitter gourd. PMID:23843889

  15. Peroxisome Proliferator-activated Receptor γ Induces Apoptosis and Inhibits Autophagy of Human Monocyte-derived Macrophages via Induction of Cathepsin L

    PubMed Central

    Mahmood, Dler Faieeq Darweesh; Jguirim-Souissi, Imene; Khadija, El-Hadri; Blondeau, Nicolas; Diderot, Vimala; Amrani, Souliman; Slimane, Mohamed-Naceur; Syrovets, Tatiana; Simmet, Thomas; Rouis, Mustapha

    2011-01-01

    Macrophages play a pivotal role in the pathophysiology of atherosclerosis. These cells express cathepsin L (CatL), a cysteine protease that has been implicated in atherogenesis and the associated arterial remodeling. In addition, macrophages highly express peroxisome proliferator-activated receptor (PPAR) γ, a transcription factor that regulates numerous genes important for lipid and lipoprotein metabolism, for glucose homeostasis, and inflammation. Hence, PPARγ might affect macrophage function in the context of chronic inflammation such as atherogenesis. In the present study, we examined the effect of PPARγ activation on the expression of CatL in human monocyte-derived macrophages (HMDM). Activation of PPARγ by the specific agonist GW929 concentration-dependently increased the levels of CatL mRNA and protein in HMDM. By promoter analysis, we identified a functional PPAR response element-like sequence that positively regulates CatL expression. In addition, we found that PPARγ-induced CatL promotes the degradation of Bcl2 without affecting Bax protein levels. Consistently, degradation of Bcl2 could be prevented by a specific CatL inhibitor, confirming the causative role of CatL. PPARγ-induced CatL was found to decrease autophagy through reduction of beclin 1 and LC3 protein levels. The reduction of these proteins involved in autophagic cell death was antagonized either by the CatL inhibitor or by CatL knockdown. In conclusion, our data show that PPARγ can specifically induce CatL, a proatherogenic protease, in HMDM. In turn, CatL inhibits autophagy and induces apoptosis. Thus, the proatherogenic effect of CatL could be neutralized by apoptosis, a beneficial phenomenon, at least in the early stages of atherosclerosis. PMID:21700710

  16. Yeast peroxisomes: structure, functions and biotechnological opportunities.

    PubMed

    Sibirny, Andriy A

    2016-06-01

    Peroxisomes are ubiquitous organelles found in most eukaryotic cells. In yeasts, peroxisomes play important roles in cell metabolism, especially in different catabolic processes including fatty acid β-oxidation, the glyoxylic shunt and methanol metabolism, as well as some biosynthetic processes. In addition, peroxisomes are the compartment in which oxidases and catalase are localized. New peroxisomes mainly arise by fission of pre-existing ones, although they can also be formed from the endoplasmic reticulum (ER). Peroxisomes consist of matrix-soluble proteins and membrane proteins known as peroxins. A total of 34 PEX peroxin genes and proteins have been identified to date. and their functions have been elucidated. Protein import into peroxisomes depends on peroxins and requires specific signals in the structure of transported proteins: PTS1, PTS2 and mPTS. The mechanisms of metabolite penetration into peroxisomes are still poorly understood. Peroxisome number and the volume occupied by these organelles are tightly regulated. Methanol, fatty acids and methylamine act as efficient peroxisome proliferators, whereas glucose and ethanol induce peroxisome autophagic degradation (pexophagy). To date, 42 Atg proteins involved in pexophagy are known. Catabolism and alcoholic fermentation of the major pentose sugar, xylose, depend on peroxisomal enzymes. Overexpression of peroxisomal transketolase and transaldolase activates xylose fermentation. Peroxisomes could be useful as target organelles for overexpression of foreign toxic proteins. PMID:27189367

  17. Nimesulide, a cyclooxygenase-2 selective inhibitor, suppresses obesity-related non-alcoholic fatty liver disease and hepatic insulin resistance through the regulation of peroxisome proliferator-activated receptor γ

    PubMed Central

    Tsujimoto, Shunsuke; Kishina, Manabu; Koda, Masahiko; Yamamoto, Yasutaka; Tanaka, Kohei; Harada, Yusuke; Yoshida, Akio; Hisatome, Ichiro

    2016-01-01

    Cyclooxygenase (COX)-2 selective inhibitors suppress non-alcoholic fatty liver disease (NAFLD); however, the precise mechanism of action remains unknown. The aim of this study was to examine how the COX-2 selective inhibitor nimesulide suppresses NAFLD in a murine model of high-fat diet (HFD)-induced obesity. Mice were fed either a normal chow diet (NC), an HFD, or HFD plus nimesulide (HFD-nime) for 12 weeks. Body weight, hepatic COX-2 mRNA expression and triglyceride accumulation were significantly increased in the HFD group. Triglyceride accumulation was suppressed in the HFD-nime group. The mRNA expression of hepatic peroxisome proliferator-activated receptor γ (PPARγ) and the natural PPARγ agonist 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) were significantly increased in the HFD group and significantly suppressed in the HFD-nime group. Glucose metabolism was impaired in the HFD group compared with the NC group, and it was significantly improved in the HFD-nime group. In addition, the plasma insulin levels in the HFD group were increased compared with those in the NC group, and were decreased in the HFD-nime group. These results indicate that HFD-induced NAFLD is mediated by the increased hepatic expression of COX-2. We suggest that the production of 15d-PGJ2, which is mediated by COX-2, induces NAFLD and hepatic insulin resistance by activating PPARγ. Furthermore, the mRNA expression of tissue inhibitor of metalloproteinases-1 (TIMP-1), procollagen-1 and monocyte chemoattractant protein-1 (MCP-1), as well as the number of F4/80-positive hepatic (Kupffer) cells, were significantly increased in the HFD group compared with the NC group, and they were reduced by nimesulide. In conclusion, COX-2 may emerge as a molecular target for preventing the development of NAFLD and insulin resistance in diet-related obesity. PMID:27431935

  18. White tea extract induces apoptosis in non-small cell lung cancer cells: the role of peroxisome proliferator-activated receptor-{gamma} and 15-lipoxygenases.

    PubMed

    Mao, Jenny T; Nie, Wen-Xian; Tsu, I-Hsien; Jin, Yu-Sheng; Rao, Jian Yu; Lu, Qing-Yi; Zhang, Zuo-Feng; Go, Vay Liang W; Serio, Kenneth J

    2010-09-01

    Emerging preclinical data suggests that tea possess anticarcinogenic and antimutagenic properties. We therefore hypothesize that white tea extract (WTE) is capable of favorably modulating apoptosis, a mechanism associated with lung tumorigenesis. We examined the effects of physiologically relevant doses of WTE on the induction of apoptosis in non-small cell lung cancer cell lines A549 (adenocarcinoma) and H520 (squamous cell carcinoma) cells. We further characterized the molecular mechanisms responsible for WTE-induced apoptosis, including the induction of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and the 15-lipoxygenase (15-LOX) signaling pathways. We found that WTE was effective in inducing apoptosis in both A549 and H520 cells, and inhibition of PPAR-gamma with GW9662 partially reversed WTE-induced apoptosis. We further show that WTE increased PPAR-gamma activation and mRNA expression, concomitantly increased 15(S)-hydroxy-eicosatetraenoic acid release, and upregulated 15-LOX-1 and 15-LOX-2 mRNA expression by A549 cells. Inhibition of 15-LOX with nordihydroguaiaretic acid (NGDA), as well as caffeic acid, abrogated WTE-induced PPAR-gamma activation and upregulation of PPAR-gamma mRNA expression in A549 cells. WTE also induced cyclin-dependent kinase inhibitor 1A mRNA expression and activated caspase-3. Inhibition of caspase-3 abrogated WTE-induced apoptosis. Our findings indicate that WTE is capable of inducing apoptosis in non-small cell lung cancer cell lines. The induction of apoptosis seems to be mediated, in part, through the upregulation of the PPAR-gamma and 15-LOX signaling pathways, with enhanced activation of caspase-3. Our findings support the future investigation of WTE as an antineoplastic and chemopreventive agent for lung cancer. PMID:20668019

  19. Mitogen-activated protein kinase kinases promote mitochondrial biogenesis in part through inducing peroxisome proliferator-activated receptor γ coactivator-1β expression.

    PubMed

    Gao, Minghui; Wang, Junjian; Lu, Na; Fang, Fang; Liu, Jinsong; Wong, Chi-Wai

    2011-06-01

    Growth factor activates mitogen-activated protein kinase kinases to promote cell growth. Mitochondrial biogenesis is an integral part of cell growth. How growth factor regulates mitochondrial biogenesis is not fully understood. In this study, we found that mitochondrial mass was specifically reduced upon serum starvation and induced upon re-feeding with serum. Using mitogen-activated protein kinase kinases inhibitor U0126, we found that the mRNA expression levels of ATP synthase, cytochrome-C, mitochondrial transcription factor A, and mitofusin 2 were reduced. Since the transcriptional levels of these genes are under the control of peroxisome proliferator-activated receptor γ coactivator-1α and -1β (PGC-1α and PGC-1β), we examined and found that only the mRNA and protein levels of PGC-1β were suppressed. Importantly, over-expression of PGC-1β partially reversed the reduction of mitochondrial mass upon U0126 treatment. Thus, we conclude that mitogen-activated protein kinase kinases direct mitochondrial biogenesis through selectively inducing PGC-1β expression. PMID:21458501

  20. Inducible Conditional Vascular-Specific Overexpression of Peroxisome Proliferator-Activated Receptor Beta/Delta Leads to Rapid Cardiac Hypertrophy

    PubMed Central

    Wagner, Kay-Dietrich; Vukolic, Ana; Baudouy, Delphine; Michiels, Jean-François

    2016-01-01

    Peroxisome proliferator-activated receptors are nuclear receptors which function as ligand-activated transcription factors. Among them, peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) is highly expressed in the heart and thought to have cardioprotective functions due to its beneficial effects in metabolic syndrome. As we already showed that PPARβ/δ activation resulted in an enhanced cardiac angiogenesis and growth without impairment of heart function, we were interested to determine the effects of a specific activation of PPARβ/δ in the vasculature on cardiac performance under normal and in chronic ischemic heart disease conditions. We analyzed the effects of a specific PPARβ/δ overexpression in endothelial cells on the heart using an inducible conditional vascular-specific mouse model. We demonstrate that vessel-specific overexpression of PPARβ/δ induces rapid cardiac angiogenesis and growth with an increase in cardiomyocyte size. Upon myocardial infarction, vascular overexpression of PPARβ/δ, despite the enhanced cardiac vessel formation, does not protect against chronic ischemic injury. Our results suggest that the proper balance of PPARβ/δ activation in the different cardiac cell types is required to obtain beneficial effects on the outcome in chronic ischemic heart disease. PMID:27057154

  1. Redox regulated peroxisome homeostasis

    PubMed Central

    Wang, Xiaofeng; Li, Shuo; Liu, Yu; Ma, Changle

    2014-01-01

    Peroxisomes are ubiquitous organelles present in nearly all eukaryotic cells. Conserved functions of peroxisomes encompass beta-oxidation of fatty acids and scavenging of reactive oxygen species generated from diverse peroxisomal metabolic pathways. Peroxisome content, number, and size can change quickly in response to environmental and/or developmental cues. To achieve efficient peroxisome homeostasis, peroxisome biogenesis and degradation must be orchestrated. We review the current knowledge on redox regulated peroxisome biogenesis and degradation with an emphasis on yeasts and plants. PMID:25545794

  2. Redox regulated peroxisome homeostasis.

    PubMed

    Wang, Xiaofeng; Li, Shuo; Liu, Yu; Ma, Changle

    2015-01-01

    Peroxisomes are ubiquitous organelles present in nearly all eukaryotic cells. Conserved functions of peroxisomes encompass beta-oxidation of fatty acids and scavenging of reactive oxygen species generated from diverse peroxisomal metabolic pathways. Peroxisome content, number, and size can change quickly in response to environmental and/or developmental cues. To achieve efficient peroxisome homeostasis, peroxisome biogenesis and degradation must be orchestrated. We review the current knowledge on redox regulated peroxisome biogenesis and degradation with an emphasis on yeasts and plants. PMID:25545794

  3. 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.

  4. MicroRNA-128 inhibition attenuates myocardial ischemia/reperfusion injury-induced cardiomyocyte apoptosis by the targeted activation of peroxisome proliferator-activated receptor gamma

    PubMed Central

    ZENG, XIAO CONG; LI, LANG; WEN, HONG; BI, QI

    2016-01-01

    The aim of the present study was to investigate the effects of microRNA (miR)-128 inhibition on the targeted activation of peroxisome proliferator-activated receptor gamma (PPARG) and on cardiomyocyte apoptosis induced by myocardial ischemia/reperfusion (I/R) injury. In vitro, the expression of PPARG was detected by reverse transcription-quantitative polymerase chain reaction and western blotting in neonatal rat ventricular myocytes (NRVMs) and HEK293 cells transfected with the mimics or inhibitors of miR-128 or control RNA. Luciferase reporter assays were used to identify whether PPARG is a direct target of miR-128. In vivo, miR-128 was knocked down via ear vein injection of antagomir-128 in a rabbit myocardial I/R injury model. Western blotting investigated the activation of Akt [phosphorylated (p)-Akt] and the expression of total-Akt, PPARG and myeloid leukemia cell differentiation protein-1 (Mcl-1) in the myocardium. Cardiomyocyte apoptosis was examined with transmission electron microscropy and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. PPARG mRNA and protein were downregulated in NRVMs transfected with miR-128 mimics, but upregulated by antagomir-128 compared with control. This indicates that PPARG is a direct miR-128 target. Activation of Akt (p-Akt), Mcl-1 and PPARG expression in the myocardium were increased by miR-128 inhibition. Furthermore, miR-128 antagomirs significantly reduced apoptosis in hearts subjected to I/R injury, which was blocked by the PPARG inhibitor GW9662. In conclusion, miR-128 inhibition attenuated I/R injury-induced cardiomyocyte apoptosis by the targeted activation of PPARG signaling. PMID:27150726

  5. Activation of Peroxisome Proliferator-Activated Receptor-γ Reverses Squamous Metaplasia and Induces Transitional Differentiation in Normal Human Urothelial Cells

    PubMed Central

    Varley, Claire Lucy; Stahlschmidt, Jens; Smith, Barbara; Stower, Michael; Southgate, Jennifer

    2004-01-01

    We observed that in urothelium, both cornifying and noncornifying forms of squamous metaplasia are accompanied by changes in the localization of the nuclear hormone receptors, peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid X receptor (RXR-α). To obtain objective evidence for a role for PPAR-γ-mediated signaling in urothelial differentiation, we examined expression of the cytokeratin isotypes CK13, CK20, and CK14 as indicators of transitional, terminal transitional, and squamous differentiation, respectively, in cultures of normal human urothelial cells. In control culture conditions, normal human urothelial cells showed evidence of squamous differentiation (CK14+, CK13−, CK20−). Treatment with the high-affinity PPAR-γ agonist, troglitazone (TZ), resulted in gain of CK13 and loss of CK14 protein expression. The effect of TZ was significantly augmented when the autocrine-stimulated epidermal growth factor receptor pathway was inhibited and this resulted in induction of CK20 expression. The RXR-specific inhibitors PA452, HX531, and HX603 inhibited the TZ-induced CK13 expression, supporting a role for RXR in the induction of CK13 expression. Thus, signaling through PPAR-γ can mediate transitional differentiation of urothelial cells and this is modulated by growth regulatory programs. PMID:15111325

  6. 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

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

    PubMed Central

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

    2014-01-01

    Peroxisome proliferator-activated receptor-α (PPARα) mediates metabolic remodeling, resulting in enhanced mitochondrial and peroxisomal β-oxidation of fatty acids. In addition to the physiological stimuli of fasting and high-fat diet, PPARα 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 PPARα regulation of Sirt1 gene expression. The impact of SIRT1 loss on PPARα functionality in vivo was assessed in hepatocyte-specific knockout mice that lack the deacetylase domain of SIRT1 (Sirt1ΔLiv). Knockout mice were treated with fibrates or fasted for 24 h to activate PPARα. Basal expression of the PPARα target genes Cyp4a10 and Cyp4a14 was reduced in Sirt1ΔLiv mice compared with wild-type mice. However, no difference was observed between wild-type and Sirt1ΔLiv mice in either fasting- or fibrate-mediated induction of PPARα target genes. Similar to the initial results, there was no difference in fibrate-activated PPARα gene induction. To assess the relationship between SIRT1 and PPARα in a pathophysiological setting, Sirt1ΔLiv mice were maintained on a high-fat diet for 14 wk, followed by fibrate treatment. Sirt1ΔLiv mice exhibited increased body mass compared with control mice. In the context of a high-fat diet, Sirt1ΔLiv mice did not respond to the cholesterol-lowering effects of the fibrate treatment. However, there were no significant differences in PPARα target gene expression. These results suggest that, in vivo, SIRT1 deacetylase activity does not significantly impact induced PPARα activity. PMID:24496310

  8. 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.

  9. Nimesulide, a cyclooxygenase-2 selective inhibitor, suppresses obesity-related non-alcoholic fatty liver disease and hepatic insulin resistance through the regulation of peroxisome proliferator-activated receptor γ.

    PubMed

    Tsujimoto, Shunsuke; Kishina, Manabu; Koda, Masahiko; Yamamoto, Yasutaka; Tanaka, Kohei; Harada, Yusuke; Yoshida, Akio; Hisatome, Ichiro

    2016-09-01

    Cyclooxygenase (COX)-2 selective inhibitors suppress non-alcoholic fatty liver disease (NAFLD); however, the precise mechanism of action remains unknown. The aim of this study was to examine how the COX-2 selective inhibitor nimesulide suppresses NAFLD in a murine model of high-fat diet (HFD)‑induced obesity. Mice were fed either a normal chow diet (NC), an HFD, or HFD plus nimesulide (HFD-nime) for 12 weeks. Body weight, hepatic COX-2 mRNA expression and triglyceride accumulation were significantly increased in the HFD group. Triglyceride accumulation was suppressed in the HFD-nime group. The mRNA expression of hepatic peroxisome proliferator-activated receptor γ (PPARγ) and the natural PPARγ agonist 15-deoxy-Δ12,14-prostaglandin J2 (15d‑PGJ2) were significantly increased in the HFD group and significantly suppressed in the HFD-nime group. Glucose metabolism was impaired in the HFD group compared with the NC group, and it was significantly improved in the HFD-nime group. In addition, the plasma insulin levels in the HFD group were increased compared with those in the NC group, and were decreased in the HFD-nime group. These results indicate that HFD-induced NAFLD is mediated by the increased hepatic expression of COX-2. We suggest that the production of 15d-PGJ2, which is mediated by COX-2, induces NAFLD and hepatic insulin resistance by activating PPARγ. Furthermore, the mRNA expression of tissue inhibitor of metalloproteinases-1 (TIMP‑1), procollagen-1 and monocyte chemoattractant protein-1 (MCP-1), as well as the number of F4/80-positive hepatic (Kupffer) cells, were significantly increased in the HFD group compared with the NC group, and they were reduced by nimesulide. In conclusion, COX-2 may emerge as a molecular target for preventing the development of NAFLD and insulin resistance in diet-related obesity. PMID:27431935

  10. Peroxisome proliferator-activated receptor β/δ induces myogenesis by modulating myostatin activity.

    PubMed

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

    2012-04-13

    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

  11. Multiple Peroxisomal Enzymatic Deficiency Disorders

    PubMed Central

    Vamecq, Joseph; Draye, Jean-Pierre; Van Hoof, François; 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

  12. A peroxisome proliferator-activated receptor-alpha activator induces renal CYP2C23 activity and protects from angiotensin II-induced renal injury.

    PubMed

    Muller, Dominik N; Theuer, Juergen; Shagdarsuren, Erdenechimeg; Kaergel, Eva; Honeck, Horst; Park, Joon-Keun; Markovic, Marija; Barbosa-Sicard, Eduardo; Dechend, Ralf; Wellner, Maren; Kirsch, Torsten; Fiebeler, Anette; Rothe, Michael; Haller, Hermann; Luft, Friedrich C; Schunck, Wolf-Hagen

    2004-02-01

    Cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolites are involved in the regulation of renal vascular tone and salt excretion. The epoxygenation product 11,12-epoxyeicosatrienoic acid (EET) is anti-inflammatory and inhibits nuclear factor-kappa B activation. We tested the hypothesis that the peroxisome proliferator-activated receptor-alpha-activator fenofibrate (Feno) induces CYP isoforms, AA hydroxylation, and epoxygenation activity, and protects against inflammatory organ damage. Double-transgenic rats (dTGRs) overexpressing human renin and angiotensinogen genes were treated with Feno. Feno normalized blood pressure, albuminuria, reduced nuclear factor-kappa B activity, and renal leukocyte infiltration. Renal epoxygenase activity was lower in dTGRs compared to nontransgenic rats. Feno strongly induced renal CYP2C23 protein and AA-epoxygenase activity under pathological and nonpathological conditions. In both cases, CYP2C23 was the major isoform responsible for 11,12-EET formation. Moreover, we describe a novel CYP2C23-dependent pathway leading to hydroxy-EETs (HEETs), which may serve as endogenous peroxisome proliferator-activated receptor-alpha activators. The capacity to produce HEETs via CYP2C23-dependent epoxygenation of 20-HETE and CYP4A-dependent hydroxylation of EETs was reduced in dTGR kidneys and induced by Feno. These results demonstrate that Feno protects against angiotensin II-induced renal damage and acts as inducer of CYP2C23-mediated epoxygenase activities. We propose that CYP-dependent EET/HEET production may serve as an anti-inflammatory control mechanism. PMID:14742258

  13. A Peroxisome Proliferator-Activated Receptor-α Activator Induces Renal CYP2C23 Activity and Protects from Angiotensin II-Induced Renal Injury

    PubMed Central

    Muller, Dominik N.; Theuer, Juergen; Shagdarsuren, Erdenechimeg; Kaergel, Eva; Honeck, Horst; Park, Joon-Keun; Markovic, Marija; Barbosa-Sicard, Eduardo; Dechend, Ralf; Wellner, Maren; Kirsch, Torsten; Fiebeler, Anette; Rothe, Michael; Haller, Hermann; Luft, Friedrich C.; Schunck, Wolf-Hagen

    2004-01-01

    Cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolites are involved in the regulation of renal vascular tone and salt excretion. The epoxygenation product 11,12-epoxyeicosatrienoic acid (EET) is anti-inflammatory and inhibits nuclear factor-κB activation. We tested the hypothesis that the peroxisome proliferator-activated receptor-α-activator fenofibrate (Feno) induces CYP isoforms, AA hydroxylation, and epoxygenation activity, and protects against inflammatory organ damage. Double-transgenic rats (dTGRs) overexpressing human renin and angiotensinogen genes were treated with Feno. Feno normalized blood pressure, albuminuria, reduced nuclear factor-κB activity, and renal leukocyte infiltration. Renal epoxygenase activity was lower in dTGRs compared to nontransgenic rats. Feno strongly induced renal CYP2C23 protein and AA-epoxygenase activity under pathological and nonpathological conditions. In both cases, CYP2C23 was themajor isoform responsible for 11,12-EET formation. Moreover, we describe a novel CYP2C23-dependent pathway leading to hydroxy-EETs (HEETs), which may serve as endogenous peroxisome proliferator-activated receptor-α activators. The capacity to produce HEETs via CYP2C23-dependent epoxygenation of 20-HETE and CYP4A-dependent hydroxylation of EETs was reduced in dTGR kidneys and induced by Feno. These results demonstrate that Feno protects against angiotensin II-induced renal damage and acts as inducer of CYP2C23-mediated epoxygenase activities. We propose that CYP-dependent EET/HEET production may serve as an anti-inflammatory control mechanism. PMID:14742258

  14. Fatty acid activation of peroxisome proliferator-activated receptor (PPAR).

    PubMed

    Bocos, C; Göttlicher, M; Gearing, K; Banner, C; Enmark, E; Teboul, M; Crickmore, A; Gustafsson, J A

    1995-06-01

    Peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643 have been shown to activate peroxisome proliferator-activated receptor (PPAR), a member of the steroid nuclear receptor superfamily. We have cloned the cDNA from rat that is homologous to that from mouse, which encodes a 97% similar protein. To search for physiologically occurring activators, we established a transcriptional transactivation assay by stably expressing in CHO cells a chimera of rat PPAR and the human glucocorticoid receptor that activates expression of the placental alkaline phosphatase reporter gene under the control of the mouse mammary tumor virus promoter. 150 microM concentrations of arachidonic or linoleic acid but not of dehydroepiandrosterone, cholesterol, or 25-hydroxy-cholesterol, activated the receptor chimera. In addition, saturated fatty acids induced the reporter gene. Shortening the chain length to n = 6 or introduction of an omega-terminal carboxylic group abolished the activation potential of the fatty acid. To test whether a common PPAR binding metabolite might be formed from free fatty acids we tested the effects of differentially beta-oxidizable fatty acids and inhibitors of fatty acid metabolism. The peroxisomal proliferation-inducing, non-beta-oxidizable, tetradecylthioacetic acid activated PPAR to the same extent as the strong peroxisomal proliferator WY-14,643, whereas the homologous beta-oxidizable tetradecylthiopropionic acid was only as potent as a non-substituted fatty acid. Cyclooxygenase inhibitors, radical scavengers or cytochrome P450 inhibitors did not affect activation of PPAR. In conclusion, beta-oxidation is apparently not required for the formation of the PPAR-activating molecule and this moiety might be a fatty acid, its ester with CoA, or a further derivative of the activated fatty acid prior to beta-oxidation of the acyl-CoA ester. PMID:7626496

  15. Peroxisome proliferator-activated receptor ɣ activation induces 11β-hydroxysteroid dehydrogenase type 1 activity in human alternative macrophages

    PubMed Central

    Chinetti-Gbaguidi, Giulia; Bouhlel, Mohamed Amine; Copin, Corinne; Duhem, Christian; Derudas, Bruno; Neve, Bernardette; Noel, Benoit; Eeckhoute, Jerome; Lefebvre, Philippe; Seckl, Jonathan R.; Staels, Bart

    2012-01-01

    Objectives 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyses the intracellular reduction of inactive cortisone to active cortisol, the natural ligand activating the glucocorticoid receptor (GR). Peroxisome Proliferator-Activated Receptor gamma (PPARγ) is a nuclear receptor controlling inflammation, lipid metabolism and the macrophage polarization state. In this study, we investigated the impact of macrophage polarization on the expression and activity of 11β-HSD1 and the role of PPAR therein. Methods and Results 11β-HSD1 gene expression is higher in pro-inflammatory M1 and anti-inflammatory M2 macrophages than in resting macrophages (RM), whereas its activity is highest in M2 macrophages. Interestingly, PPARγ activation induces 11β-HSD1 enzyme activity in M2 macrophages, but not in RM or M1 macrophages. Consequently, human M2 macrophages displayed enhanced responsiveness to the 11β-HSD1 substrate cortisone, an effect amplified by PPAR -induction of 11β-HSD1 activity, as illustrated by an increased expression of GR target genes. Conclusions Our data identify a positive cross-talk between PPARγ and GR in human M2 macrophages via the induction of 11β-HSD1 expression and activity. PMID:22207732

  16. Troglitazone, the peroxisome proliferator-activated receptor-gamma agonist, induces antiproliferation and redifferentiation in human thyroid cancer cell lines.

    PubMed

    Park, Jin-Woo; Zarnegar, Rasa; Kanauchi, Hajime; Wong, Mariwil G; Hyun, William C; Ginzinger, David G; Lobo, Margaret; Cotter, Philip; Duh, Quan-Yang; Clark, Orlo H

    2005-03-01

    Troglitazone is a potent agonist for the peroxisome proliferator-activated receptor-gamma (PPARgamma) that is a ligand-activated transcription factor regulating cell differentiation and growth. PPARgamma may play a role in thyroid carcinogenesis since PAX8-PPARgamma1 chromosomal translocations are commonly found in follicular thyroid cancers. We investigated the antiproliferative and redifferentiation effects of troglitazone in 6 human thyroid cancer cell lines: TPC-1 (papillary), FTC-133, FTC-236, FTC-238 (follicular), XTC-1 (Hürthle cell), and ARO82-1 (anaplastic) cell lines. PPARgamma was expressed variably in these cell lines. FTC-236 and FTC-238 had a rearranged chromosome at 3p25, possibly implicating the involvement of the PPARgamma encoding gene whereas the other cell lines did not. Troglitazone significantly inhibited cell growth by cell cycle arrest and apoptotic cell death. PPARgamma overexpression did not appear to be a prerequisite for a response to treatment with troglitazone. Troglitazone also downregulated surface expression of CD97, a novel dedifferentiation marker, in FTC-133 cells and upregulated sodium iodide symporter (NIS) mRNA in TPC-1 and FTC-133 cells. Our investigations document that human thyroid cancer cell lines commonly express PPARgamma, but chromosomal translocations involving PPARgamma are uncommon. Troglitazone, a PPARgamma agonist, induced antiproliferation and redifferentiation in thyroid cancer cell lines. PPARgamma agonists may therefore be effective therapeutic agents for the treatment of patients with thyroid cancer that fails to respond to traditional treatments. PMID:15785241

  17. Activating Peroxisome Proliferator-Activated Receptors (PPARs): a New Sight for Chrysophanol to Treat Paraquat-Induced Lung Injury.

    PubMed

    Li, Ang; Liu, Yuguang; Zhai, Lu; Wang, Liying; Lin, Zhe; Wang, Shumin

    2016-04-01

    The aim of this study is to evaluate the protective effects of chrysophanol (CH) against paraquat (PQ)-induced pulmonary injury. Fifty BALB/C mice were randomized into five groups: (1) control, (2) PQ, (3) PQ + dexamethasone (Dex, 2 mg/kg), (4) PQ + CH (10 mg/kg), and (5) PQ + CH (20 mg/kg). A single dose of PQ (50 mg/kg, i.p.) was intraperitoneally given to induce acute lung injury. Then mice were treated with CH (10 and 20 mg/kg/day, orally) for 7 days. At the end of the experiment, animals were euthanized and then bronchoalveolar lavage fluid (BALF) and lung tissues were collected for histological observation, biochemical analysis, and Western blot analysis. Malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) levels in BALF were determined. The levels of SOD and MDA in the lung were also detected. The peroxisome proliferator-activated receptor (PPAR)-γ and nuclear factor-kappaB (NF-κB) pathway proteins in the lung were determined by Western blot. Histological examination indicated that CH attenuated lung inflammation caused by PQ. Biochemical results showed that CH treatment significantly reduced the levels of MDA, MPO, and inflammatory cytokines and increased the level of SOD, compared to those in the PQ group. Meanwhile, Western Blot results revealed that CH increased PPAR-γ expression and inhibited NF-κB pathway activation after PQ challenge. These findings suggested the potential therapeutic effects of CH which is derived from a natural product on PQ-induced pulmonary injury. PMID:26920845

  18. Peroxisome Proliferator-Activated Receptor-α Inhibition Protects Against Doxorubicin-Induced Cardiotoxicity in Mice.

    PubMed

    Rahmatollahi, Mahdieh; Baram, Somayeh Mahmoodi; Rahimian, Reza; Saeedi Saravi, Seyed Soheil; Dehpour, Ahmad Reza

    2016-07-01

    Doxorubicin is an effective chemotherapeutic drug against a considerable number of malignancies. However, its toxic effects on myocardium are confirmed as major limit of utilization. PPAR-α is highly expressed in the heart, and its activation leads to an increased cardiac fatty acid oxidation and cardiomyocyte necrosis. This study was performed to adjust the hypothesis that PPAR-α receptor inhibition protects against doxorubicin-induced cardiac dysfunction in mice. Male Balb/c mice were used in this study. Left atria were isolated, and their contractility was measured in response to electrical field stimulation in a standard organ bath. PPAR-α activity was measured using specific PPAR-α antibody in an ELISA-based system coated with double-strand DNA containing PPAR-α response element sequence. Moreover, cardiac MDA and TNF-α levels were measured by ELISA method. Following incubation with doxorubicin (35 µM), a significant reduction in atrial contractility was observed (P < 0.001). Pretreatment of animals with a selective PPAR-α antagonist, GW6471, significantly improved doxorubicin-induced atrial dysfunction (P < 0.001). Furthermore, pretreatment of the mice with a non-selective cannabinoid agonist, WIN55212-2, significantly decreased PPAR-α activity in cardiac tissue, subsequently leading to significant improvement in doxorubicin-induced atrial dysfunction (P < 0.001). Also, GW6471 and WIN significantly reduced cardiac MDA and TNF-α levels compared with animals receiving doxorubicin (P < 0.001). The study showed that inhibition of PPAR-α is associated with protection against doxorubicin-induced cardiotoxicity in mice, and cannabinoids can potentiate the protection by PPAR-α blockade. Moreover, PPAR-α may be considered as a target to prevent cardiotoxicity induced by doxorubicin in patients undergoing chemotherapy. PMID:26082188

  19. 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

  20. Peroxisome Proliferator-Activated Receptor γ 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 γ (PPARγ) 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 PPARγ 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 PPARγ knockout mice, whereas miR-98 levels were increased and ET-1 and PCNA expression was reduced in lungs from endothelial-targeted PPARγ-overexpression mice. Gain or loss of PPARγ function in PAECs in vitro confirmed that alterations in PPARγ were sufficient to regulate miR-98, ET-1, and PCNA expression. Finally, PPARγ 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 PPARγ regulates miR-98 to modulate ET-1 expression and PAEC proliferation. These results further clarify molecular mechanisms by which PPARγ participates in PH pathogenesis and therapy. PMID:26098770

  1. 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

  2. Highly Oxidized Peroxisomes Are Selectively Degraded via Autophagy in Arabidopsis[C][W

    PubMed Central

    Shibata, Michitaro; Oikawa, Kazusato; Yoshimoto, Kohki; Kondo, Maki; Mano, Shoji; Yamada, Kenji; Hayashi, Makoto; Sakamoto, Wataru; Ohsumi, Yoshinori; Nishimura, Mikio

    2013-01-01

    The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (ATG2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peup1 mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis. PMID:24368788

  3. Transient complex peroxisomal interactions

    PubMed Central

    Bonekamp, Nina A.; Schrader, Michael

    2012-01-01

    Mitochondria and peroxisomes are ubiquitous subcellular organelles that fulfill essential metabolic functions, rendering them indispensable for human development and health. Both are highly dynamic organelles that can undergo remarkable changes in morphology and number to accomplish cellular needs. While mitochondrial dynamics are also regulated by frequent fusion events, the fusion of mature peroxisomes in mammalian cells remained a matter of debate. In our recent study, we clarified systematically that there is no complete fusion of mature peroxisomes analogous to mitochondria. Moreover, in contrast to key division components such as DLP1, Fis1 or Mff, mitochondrial fusion proteins were not localized to peroxisomes. However, we discovered and characterized novel transient, complex interactions between individual peroxisomes which may contribute to the homogenization of the often heterogeneous peroxisomal compartment, e.g., by distribution of metabolites, signals or other “molecular information” via interperoxisomal contact sites. PMID:23336019

  4. Activation of β-Adrenoceptors by Dobutamine May Induce a Higher Expression of Peroxisome Proliferator-Activated Receptors δ (PPARδ) in Neonatal Rat Cardiomyocytes

    PubMed Central

    Chou, Ming-Ting; Lo, Shih-Hsiang; Cheng, Kai-Chun; Li, Yin-Xiao; Chen, Li-Jen; Cheng, Juei-Tang

    2012-01-01

    Recent evidence showed the role of peroxisome proliferator-activated receptors (PPARs) in cardiac function. Cardiac contraction induced by various agents is critical in restoring the activity of peroxisome proliferator-activated receptors δ (PPARδ) in cardiac myopathy. Because dobutamine is an agent widely used to treat heart failure in emergency setting, this study is aimed to investigate the change of PPARδ in response to dobutamine. Neonatal rat cardiomyocytes were used to examine the effects of dobutamine on PPARδ expression levels and cardiac troponin I (cTnI) phosphorylation via Western blotting analysis. We show that treatment with dobutamine increased PPARδ expression and cTnI phosphorylation in a time- and dose-dependent manner in neonatal rat cardiomyocytes. These increases were blocked by the antagonist of β1-adrenoceptors. Also, the action of dobutamine was related to the increase of calcium ions and diminished by chelating intracellular calcium. Additionally, dobutamine-induced action was reduced by the inhibition of downstream messengers involved in this calcium-related pathway. Moreover, deletion of PPARδ using siRNA generated the reduction of cTnI phosphorylation in cardiomyocytes treated with dobutamine. Thus, we concluded that PPARδ is increased by dobutamine in cardiac cells. PMID:22666095

  5. The dietary histone deacetylase inhibitor sulforaphane induces human β-defensin-2 in intestinal epithelial cells

    PubMed Central

    Schwab, Markus; Reynders, Veerle; Loitsch, Stefan; Steinhilber, Dieter; Schröder, Oliver; Stein, Jürgen

    2008-01-01

    Antimicrobial peptides like human β-defensin-2 (HBD-2) play an important role in the innate immune system protecting the intestinal mucosa against bacterial invasion. The dietary histone deacetylase (HDAC) inhibitors sulforaphane (SFN) and butyrate have received a great deal of attention because of their ability to simultaneously modulate multiple cellular targets involved in cellular protection. In this study the influence of SFN and butyrate on HBD-2 expression as well as the molecular pathways involved in SFN-mediated induction of HBD-2 were scrutinized. Treatment of Caco-2, HT-29 and SW480 cells with SFN led to a time- and dose-dependent upregulation of HBD-2 mRNA expression as determined by semi-quantitative reverse transcription–polymerase chain reaction. Moreover, HBD-2 protein production increased in response to SFN, measured by enzyme-linked immunosorbent assay. Induction of HBD-2 was also observed in response to butyrate. Immunofluorescence analysis revealed that the protein was localized in the cytosol. Coincubation of SFN with a vitamin D receptor (VDR), or an extracellular-regulated kinase 1/2 or a nuclear factor-κB inhibitor all reduced HBD-2 mRNA upregulation. In contrast, transfection of cells with a dominant-negative peroxisome proliferator-activated receptor γ (PPARγ) mutant vector to inhibit PPARγ wild-type action and inhibition of p38 mitogen-activated protein kinase (MAPK) signalling did not affect SFN-mediated upregulation of HBD-2 mRNA. Moreover, SFN induced the expression of VDR, PPARγ and phosphorylated ERK1/2 but did not affect p38 MAPK activation. The data clearly demonstrate for the first time that the dietary HDAC inhibitor SFN is able to induce antimicrobial peptides in colonocytes. In this process HBD-2 expression is regulated via VDR, mitogen-activated protein kinase kinase/extracellular-regulated kinase and nuclear factor-κB signalling. PMID:18373608

  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. Advanced glycation end products induce peroxisome proliferator-activated receptor γ down-regulation-related inflammatory signals in human chondrocytes via Toll-like receptor-4 and receptor for advanced glycation end products.

    PubMed

    Chen, Ying Ju; Sheu, Meei Ling; Tsai, Keh Sung; Yang, Rong Sen; Liu, Shing Hwa

    2013-01-01

    Accumulation of advanced glycation end products (AGEs) in joints is important in the development of cartilage destruction and damage in age-related osteoarthritis (OA). The aim of this study was to investigate the roles of peroxisome proliferator-activated receptor γ (PPARγ), toll-like receptor 4 (TLR4), and receptor for AGEs (RAGE) in AGEs-induced inflammatory signalings in human OA chondrocytes. Human articular chondrocytes were isolated and cultured. The productions of metalloproteinase-13 and interleukin-6 were quantified using the specific ELISA kits. The expressions of related signaling proteins were determined by Western blotting. Our results showed that AGEs enhanced the productions of interleukin-6 and metalloproteinase-13 and the expressions of cyclooxygenase-2 and high-mobility group protein B1 and resulted in the reduction of collagen II expression in human OA chondrocytes. AGEs could also activate nuclear factor (NF)-κB activation. Stimulation of human OA chondrocytes with AGEs significantly induced the up-regulation of TLR4 and RAGE expressions and the down-regulation of PPARγ expression in a time- and concentration-dependent manner. Neutralizing antibodies of TLR4 and RAGE effectively reversed the AGEs-induced inflammatory signalings and PPARγ down-regulation. PPARγ agonist pioglitazone could also reverse the AGEs-increased inflammatory signalings. Specific inhibitors for p38 mitogen-activated protein kinases, c-Jun N-terminal kinase and NF-κB suppressed AGEs-induced PPARγ down-regulation and reduction of collagen II expression. Taken together, these findings suggest that AGEs induce PPARγ down-regulation-mediated inflammatory signalings and reduction of collagen II expression in human OA chondrocytes via TLR4 and RAGE, which may play a crucial role in the development of osteoarthritis pathogenesis induced by AGEs accumulation. PMID:23776688

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

    PubMed Central

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

    2011-01-01

    Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that promotes differentiation and cell survival in the stomach. PPARγ upregulates and interacts with caveolin-1 (Cav1), a scaffold protein of Ras/mitogen-activated protein kinases (MAPKs). The cytoplasmic-to-nuclear localization of PPARγ is altered in gastric cancer (GC) patients, suggesting a so-far-unknown role for Cav1 in spatial regulation of PPARγ 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 PPARγ and enhanced nuclear translocation and ligand-independent transcription of PPARγ target genes. In contrast, Cav1 overexpression sequestered PPARγ in the cytosol through interaction of the Cav1 scaffolding domain (CSD) with a conserved hydrophobic motif in helix 7 of PPARγ's ligand-binding domain. Cav1 cooperated with the endogenous Ras/MAPK inhibitor docking protein 1 (Dok1) to promote the ligand-dependent transcriptional activity of PPARγ and to inhibit cell proliferation. Ligand-activated PPARγ 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 PPARγ regulation by which Ras/MAPK inhibitors act as scaffold proteins that sequester and sensitize PPARγ to ligands, limiting proliferation of gastric epithelial cells. PMID:21690289

  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-α, interleukin-1β (IL-1β) and IL-6, in the bronchoalveolar lavage fluid and lung tissues after LPS challenge, while the peroxisome proliferator-activated receptor γ (PPARγ) inhibitor GW9662 reversed these effects. In vitro results indicated that wogonin significantly decreased the secretion of IL-6, IL-1β and tumour necrosis factor-α in Ana-1 and RAW264.7 cells, which was suppressed by transfection of PPARγ small interfering RNA and GW9662 treatment. Moreover, wogonin activated PPARγ, induced PPARγ-mediated attenuation of the nuclear translocation and the DNA-binding activity of nuclear factor-κB 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 PPARγ-involved nuclear factor-κB pathway. PMID:24766487

  10. [BRAF Inhibitor-Induced Erythema Nodosum-Like Lesions].

    PubMed

    Shiba, Keiko; Moriuchi, Reine; Morita, Yusuke; Nakamura, Michio; Takigami, Masayoshi; Shimizu, Satoko

    2016-05-01

    BRAF inhibitors have been licensed for the treatment of unresectable or metastatic BRAF-mutated melanomas. In Japan, the BRAF inhibitor vemurafenib has been available since December 2014. Several adverse events induced by BRAF inhibitors have been reported, such as Stevens-Johnson syndrome, toxic epidermal necrosis, squamous cell carcinoma, secondary melanoma, and hand-foot syndrome. Recently, inflammatory skin lesions clinically resembling erythema nodosum have been reported as side effects that may lead to treatment discontinuation. In this report, we described the first Japanese case of erythema nodosum-like lesions induced by vemurafenib and discussed the countermeasures to this adverse reaction. Dose reduction or interruption of BRAF inhibitors should be considered on a case-by-case basis because the condition may resolve spontaneously or under symptomatic treatment. We postulate that erythema nodosum-like lesions can be controlled by careful follow-up and supportive care. PMID:27210102

  11. 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

  12. Human peroxisomal disorders.

    PubMed

    Depreter, Marianne; Espeel, Marc; Roels, Frank

    2003-06-01

    Peroxisomes are single membrane-bound cell organelles performing numerous metabolic functions. The present article aims to give an overview of our current knowledge about inherited peroxisomal disorders in which these organelles are lacking or one or more of their functions are impaired. They are multiorgan disorders and the nervous system is implicated in most. After a summary of the historical names and categories, each having distinct symptoms and prognosis, microscopic pathology is reviewed in detail. Data from the literature are added to experience in the authors' laboratory with 167 liver biopsy and autopsy samples from peroxisomal patients, and with a smaller number of chorion samples for prenatal diagnosis, adrenal-, kidney-, and brain samples. Various light and electron microscopic methods are used including enzyme- and immunocytochemistry, polarizing microscopy, and morphometry. Together with other laboratory investigations and clinical data, this approach continues to contribute to the diagnosis and further characterization of peroxisomal disorders, and the discovery of novel variants. When liver specimens are examined, three main groups including 9 novel variants (33 patients) are distinguished: (1) absence or (2) presence of peroxisomes, and (3) mosaic distribution of cells with and without peroxisomes (10 patients). Renal microcysts, polarizing trilamellar inclusions, and insoluble lipid in macrophages in liver, adrenal cortex, brain, and in interstitial cells of kidney are also valuable for classification. On a genetic basis, complementation of fibroblasts has classified peroxisome biogenesis disorders into 12 complementation groups. Peroxisome biogenesis genes (PEX), knock-out-mice, and induction of redundant genes are briefly reviewed, including some recent results with 4-phenylbutyrate. Finally, regulation of peroxisome expression during development and in cell cultures, and by physiological factors is discussed. PMID:12740827

  13. Peroxisome proliferator activated receptor α (PPARα) and PPAR gamma coactivator (PGC-1α) induce carnitine palmitoyltransferase IA (CPT-1A) via independent gene elements

    PubMed Central

    Song, Shulan; Attia, Ramy R.; Connaughton, Sara; Niesen, Melissa I.; Ness, Gene C.; Elam, Marshall B.; Hori, Roderick T.; Cook, George A.; Park, Edwards A.

    2010-01-01

    Long chain fatty acids and pharmacologic ligands for the peroxisome proliferator activated receptor alpha (PPARα) activate expression of genes involved in fatty acid and glucose oxidation including carnitine palmitoyltransferase-1A (CPT-1A) and pyruvate dehydrogenase kinase 4 (PDK4). CPT-1A catalyzes the transfer of long chain fatty acids from acyl-CoA to carnitine for translocation across the mitochondrial membranes and is an initiating step in the mitochondrial oxidation of long chain fatty acids. PDK4 phosphorylates and inhibits the pyruvate dehydrogenase complex (PDC) which catalyzes the conversion of pyruvate to acetyl-CoA in the glucose oxidation pathway. The activity of CPT-1A is modulated both by transcriptional changes as well as by malonyl-CoA inhibition. In the liver, CPT-1A and PDK4 gene expression are induced by starvation, high fat diets and PPARα ligands. Here, we characterized a binding site for PPARα in the second intron of the rat CPT-1A gene. Our studies indicated that WY14643 and long chain fatty acids induce CPT-1A gene expression through this element. In addition, we found that mutation of the PPARα binding site reduced the expression of CPT-1A-luciferase vectors in the liver of fasted rats. We had demonstrated previously that CPT-1A was stimulated by the peroxisome proliferator activated receptor gamma coactivator (PGC-1α) via sequences in the first intron of the rat CPT-1A gene. Surprisingly, PGC-1α did not enhance CPT-1A transcription through the PPARα binding site in the second intron. Following knockdown of PGC-1α with short hairpin RNA, the CPT-1A and PDK4 genes remained responsive to WY14643. Overall, our studies indicated that PPARα and PGC-1α stimulate transcription of the CPT-1A gene through different regions of the CPT-1A gene. PMID:20638986

  14. Expression regulation and targeting of the peroxisome proliferator-activated receptor γ 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 γ (PPARγ) agonist rosiglitazone are of particular interest for disease-modifying and antiepileptogenic approaches. We studied the expression of PPARγ 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 PPARγ 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

  15. Peroxisome proliferator-activated receptor δ (PPARδ) induces estrogen receptor-positive mammary neoplasia through an inflammatory and metabolic phenotype linked to mTor activation

    PubMed Central

    Yuan, Hongyan; Lu, Jin; Xiao, Junfeng; Upadhyay, Geeta; Umans, Rachel; Kallakury, Bhaskar; Yin, Yuhzi; Fant, Michael E.; Kopelovich, Levy; Glazer, Robert I.

    2013-01-01

    The peroxisome proliferator-activated receptor-δ (PPARδ) regulates a multitude of physiological processes associated with glucose and lipid metabolism, inflammation and proliferation. One or more of these processes are potential risk factors for the ability of PPARδ agonists to promote tumorigenesis in the mammary gland. In the present study, we describe a new transgenic mouse model in which activation of PPARδ in the mammary epithelium by endogenous or synthetic ligands resulted in progressive histopathological changes that culminated in the appearance of estrogen receptor- and progesterone receptor-positive and ErbB2-negative infiltrating ductal carcinomas. Multiparous mice presented with mammary carcinomas after a latency of 12 months, and administration of the PPARδ ligand GW501516 reduced tumor latency to five months. Histopathological changes occurred concurrently with an increase in an inflammatory, invasive, metabolic and proliferative gene signature, including expression of the trophoblast gene, Plac1, beginning one week after GW501516 treatment, and remained elevated throughout tumorigenesis. The appearance of malignant changes correlated with a pronounced increase in phosphatidylcholine and lysophosphatidic acid metabolites, which coincided with activation of Akt and mTor signaling that were attenuated by treatment with the mTor inhibitor everolimus. Our findings are the first to demonstrate a direct role of PPARδ in the pathogenesis of mammary tumorigenesis, and suggest a rationale for therapeutic approaches to prevent and treat this disease. PMID:23811944

  16. 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.

  17. Isorhamnetin Inhibits Proliferation and Invasion and Induces Apoptosis through the Modulation of Peroxisome Proliferator-activated Receptor γ 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 γ (PPAR-γ) 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-γ inhibitor. We found that IH increased PPAR-γ activity and modulated the expression of PPAR-γ regulated genes in GC cells. Also, the increase in PPAR-γ activity was reversed in the presence of PPAR-γ-specific inhibitor and a mutated PPAR-γ dominant negative plasmid, supporting our hypothesis that IH can act as a ligand of PPAR-γ. 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-γ that are reported to be critical for its activity and could competitively bind to PPAR-γ. IH significantly increased the expression of PPAR-γ 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-γ activation pathway in GC. PMID:22992727

  18. Plant Peroxisomes: Biogenesis and Function

    PubMed Central

    Hu, Jianping; Baker, Alison; Bartel, Bonnie; Linka, Nicole; Mullen, Robert T.; Reumann, Sigrun; Zolman, Bethany K.

    2012-01-01

    Peroxisomes are eukaryotic organelles that are highly dynamic both in morphology and metabolism. Plant peroxisomes are involved in numerous processes, including primary and secondary metabolism, development, and responses to abiotic and biotic stresses. Considerable progress has been made in the identification of factors involved in peroxisomal biogenesis, revealing mechanisms that are both shared with and diverged from non-plant systems. Furthermore, recent advances have begun to reveal an unexpectedly large plant peroxisomal proteome and have increased our understanding of metabolic pathways in peroxisomes. Coordination of the biosynthesis, import, biochemical activity, and degradation of peroxisomal proteins allows for highly dynamic responses of peroxisomal metabolism to meet the needs of a plant. Knowledge gained from plant peroxisomal research will be instrumental to fully understanding the organelle’s dynamic behavior and defining peroxisomal metabolic networks, thus allowing the development of molecular strategies for rational engineering of plant metabolism, biomass production, stress tolerance, and pathogen defense. PMID:22669882

  19. Activation of peroxisome proliferator-activated receptor α 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) α, alone and in conjunction with all-trans-retinoic acid is capable of enhancing TFEB in brain cells. We also observed that PPARα, but not PPARβ and PPARγ, is involved in gemfibrozil-mediated up-regulation of TFEB. Reporter assay and chromatin immunoprecipitation studies confirmed the recruitment of retinoid X receptor α, PPARα, and PGC1α 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

  20. Ginger extract prevents high-fat diet-induced obesity in mice via activation of the peroxisome proliferator-activated receptor δ 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 δ (PPARδ) stimulators represent potential treatment options for obesity. Ginger (Zingiber officinale Roscoe) was previously shown to regulate the PPARγ 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 PPARδ-targeted gene expression in skeletal muscle and the liver. 6-Shogaol and 6-gingerol acted as specific PPARδ ligands and stimulated PPARδ-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 PPARδ 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 PPARδ signaling. PMID:26101135

  1. Constitutive active/androstane receptor, peroxisome proliferator-activated receptor α, 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 1000 ppm 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 α (PPARα) 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, PPARα activation, and cytotoxicity were involved in the development of liver tumors. Moreover, porphyrin was not apparently involved in OX-induced tumor development. PMID:26710982

  2. Peroxisome proliferator-activated receptor alpha acts as a mediator of endoplasmic reticulum stress-induced hepatocyte apoptosis in acute liver failure

    PubMed Central

    Zhang, Li; Ren, Feng; Zhang, Xiangying; Wang, Xinxin; Shi, Hongbo; Zhou, Li; Zheng, Sujun; Chen, Yu; Chen, Dexi; Li, Liying; Duan, Zhongping

    2016-01-01

    ABSTRACT Peroxisome proliferator-activated receptor α (PPARα) is a key regulator to ameliorate liver injury in cases of acute liver failure (ALF). However, its regulatory mechanisms remain largely undetermined. Endoplasmic reticulum stress (ER stress) plays an important role in a number of liver diseases. This study aimed to investigate whether PPARα activation inhibits ER stress-induced hepatocyte apoptosis, thereby protecting against ALF. In a murine model of D-galactosamine (D-GalN)- and lipopolysaccharide (LPS)-induced ALF, Wy-14643 was administered to activate PPARα, and 4-phenylbutyric acid (4-PBA) was administered to attenuate ER stress. PPARα activation ameliorated liver injury, because pre-administration of its specific inducer, Wy-14643, reduced the serum aminotransferase levels and preserved liver architecture compared with that of controls. The protective effect of PPARα activation resulted from the suppression of ER stress-induced hepatocyte apoptosis. Indeed, (1) PPARα activation decreased the expression of glucose-regulated protein 78 (Grp78), Grp94 and C/EBP-homologous protein (CHOP) in vivo; (2) the liver protection by 4-PBA resulted from the induction of PPARα expression, as 4-PBA pre-treatment promoted upregulation of PPARα, and inhibition of PPARα by small interfering RNA (siRNA) treatment reversed liver protection and increased hepatocyte apoptosis; (3) in vitro PPARα activation by Wy-14643 decreased hepatocyte apoptosis induced by severe ER stress, and PPARα inhibition by siRNA treatment decreased the hepatocyte survival induced by mild ER stress. Here, we demonstrate that PPARα activation contributes to liver protection and decreases hepatocyte apoptosis in ALF, particularly through regulating ER stress. Therefore, targeting PPARα could be a potential therapeutic strategy to ameliorate ALF. PMID:27482818

  3. Peroxisome proliferator-activated receptor alpha acts as a mediator of endoplasmic reticulum stress-induced hepatocyte apoptosis in acute liver failure.

    PubMed

    Zhang, Li; Ren, Feng; Zhang, Xiangying; Wang, Xinxin; Shi, Hongbo; Zhou, Li; Zheng, Sujun; Chen, Yu; Chen, Dexi; Li, Liying; Zhao, Caiyan; Duan, Zhongping

    2016-07-01

    Peroxisome proliferator-activated receptor α (PPARα) is a key regulator to ameliorate liver injury in cases of acute liver failure (ALF). However, its regulatory mechanisms remain largely undetermined. Endoplasmic reticulum stress (ER stress) plays an important role in a number of liver diseases. This study aimed to investigate whether PPARα activation inhibits ER stress-induced hepatocyte apoptosis, thereby protecting against ALF. In a murine model of D-galactosamine (D-GalN)- and lipopolysaccharide (LPS)-induced ALF, Wy-14643 was administered to activate PPARα, and 4-phenylbutyric acid (4-PBA) was administered to attenuate ER stress. PPARα activation ameliorated liver injury, because pre-administration of its specific inducer, Wy-14643, reduced the serum aminotransferase levels and preserved liver architecture compared with that of controls. The protective effect of PPARα activation resulted from the suppression of ER stress-induced hepatocyte apoptosis. Indeed, (1) PPARα activation decreased the expression of glucose-regulated protein 78 (Grp78), Grp94 and C/EBP-homologous protein (CHOP) in vivo; (2) the liver protection by 4-PBA resulted from the induction of PPARα expression, as 4-PBA pre-treatment promoted upregulation of PPARα, and inhibition of PPARα by small interfering RNA (siRNA) treatment reversed liver protection and increased hepatocyte apoptosis; (3) in vitro PPARα activation by Wy-14643 decreased hepatocyte apoptosis induced by severe ER stress, and PPARα inhibition by siRNA treatment decreased the hepatocyte survival induced by mild ER stress. Here, we demonstrate that PPARα activation contributes to liver protection and decreases hepatocyte apoptosis in ALF, particularly through regulating ER stress. Therefore, targeting PPARα could be a potential therapeutic strategy to ameliorate ALF. PMID:27482818

  4. 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.

  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. 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,...

  7. [Hereditary peroxisomal diseases].

    PubMed

    Astudillo, Leonardo; Sabourdy, Frédérique; Touati, Guy; Levade, Thierry

    2016-03-01

    Peroxisomes are small intracellular organelles that catalyse key metabolic reactions such as the beta-oxidation of some straight-chain or branched-chain fatty acids and the alpha-oxidation of phytanic acid. These enzyme reactions produce hydrogen peroxide, which is subsequently neutralized by the peroxisomal catalase. Peroxisomes also metabolize glyoxylate to glycine, and catalyze the first steps of plasmalogen biosynthesis. There are more than a dozen inherited peroxisomal disorders in humans. These metabolic diseases are due to monogenic defects that affect either a single function (such as enzyme or a transporter) or more than two distinct functions because of the impairment of several aspects of peroxisome biogenesis. With the notable exception of X-linked adrenoleucodystrophy, these inborn disorders are transmitted as autosomal recessive traits. Their clinical presentation can be very heterogeneous, and include neonatal, infantile or adult forms. The present review describes the symptomatology of these genetic diseases, the underlying genetic and biochemical alterations, and summarizes their diagnostic approach. PMID:26899150

  8. 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.

  9. Src is activated by the nuclear receptor peroxisome proliferator-activated receptor β/δ in ultraviolet radiation-induced skin cancer

    PubMed Central

    Montagner, Alexandra; Delgado, Maria B; Tallichet-Blanc, Corinne; Chan, Jeremy S K; Sng, Ming K; Mottaz, Hélène; Degueurce, Gwendoline; Lippi, Yannick; Moret, Catherine; Baruchet, Michael; Antsiferova, Maria; Werner, Sabine; Hohl, Daniel; Al Saati, Talal; Farmer, Pierre J; Tan, Nguan S; Michalik, Liliane; Wahli, Walter

    2014-01-01

    Although non-melanoma skin cancer (NMSC) is the most common human cancer and its incidence continues to rise worldwide, the mechanisms underlying its development remain incompletely understood. Here, we unveil a cascade of events involving peroxisome proliferator-activated receptor (PPAR) β/δ and the oncogene Src, which promotes the development of ultraviolet (UV)-induced skin cancer in mice. UV-induced PPARβ/δ activity, which directly stimulated Src expression, increased Src kinase activity and enhanced the EGFR/Erk1/2 signalling pathway, resulting in increased epithelial-to-mesenchymal transition (EMT) marker expression. Consistent with these observations, PPARβ/δ-null mice developed fewer and smaller skin tumours, and a PPARβ/δ antagonist prevented UV-dependent Src stimulation. Furthermore, the expression of PPARβ/δ positively correlated with the expression of SRC and EMT markers in human skin squamous cell carcinoma (SCC), and critically, linear models applied to several human epithelial cancers revealed an interaction between PPARβ/δ and SRC and TGFβ1 transcriptional levels. Taken together, these observations motivate the future evaluation of PPARβ/δ modulators to attenuate the development of several epithelial cancers. PMID:24203162

  10. A Selective Novel Peroxisome Proliferator–Activated Receptor (PPAR)-α Antagonist Induces Apoptosis and Inhibits Proliferation of CLL Cells In Vitro and In Vivo

    PubMed Central

    Messmer, Davorka; Lorrain, Kymmy; Stebbins, Karin; Bravo, Yalda; Stock, Nicholas; Cabrera, Geraldine; Correa, Lucia; Chen, Austin; Jacintho, Jason; Chiorazzi, Nicholas; Yan, Xiao Jie; Spaner, David; Prasit, Peppi; Lorrain, Daniel

    2015-01-01

    Tumor-specific metabolic changes can reveal new therapeutic targets. Our findings implicate a supporting role for fatty acid metabolism in chronic lymphocytic leukemia (CLL) cell survival. Peroxisome proliferator–activated receptor (PPAR)-α, a major transcriptional regulator of fatty acid oxidation, was recently shown to be upregulated in CLL. To evaluate PPARα as a potential therapeutic target, we developed a highly selective, potent small molecule antagonist of PPARα, NXT629. NXT629 inhibited agonist-induced transcription of PPARα-regulated genes, demonstrating target engagement in CLL cells. Furthermore, NXT629 induced apoptosis of CLL cells even in the presence of a protective microenvironment. To mimic the proliferative lymphoid compartment of CLL, we examined the activity of NXT629 on CLL cells that were stimulated to proliferate in vitro. NXT629 reduced the number of leukemia cells undergoing cell division. In addition, in two xenograft mouse models of CLL (one a model for nondividing and one for dividing CLL), NXT629 reduced the number of viable CLL cells in vivo. Overall, these results suggest that fatty acid metabolism promotes survival and proliferation of primary CLL cells and that inhibiting PPARα gene regulation could be a new therapeutic approach to treating CLL. PMID:26070013

  11. Src is activated by the nuclear receptor peroxisome proliferator-activated receptor β/δ in ultraviolet radiation-induced skin cancer.

    PubMed

    Montagner, Alexandra; Delgado, Maria B; Tallichet-Blanc, Corinne; Chan, Jeremy S K; Sng, Ming K; Mottaz, Hélén; Degueurce, Gwendoline; Lippi, Yannick; Moret, Catherine; Baruchet, Michael; Antsiferova, Maria; Werner, Sabine; Hohl, Daniel; Saati, Talal Al; Farmer, Pierre J; Tan, Nguan S; Michalik, Liliane; Wahli, Walter

    2014-01-01

    Although non-melanoma skin cancer (NMSC) is the most common human cancer and its incidence continues to rise worldwide, the mechanisms underlying its development remain incompletely understood. Here, we unveil a cascade of events involving peroxisome proliferator-activated receptor (PPAR) β/δ and the oncogene Src, which promotes the development of ultraviolet (UV)-induced skin cancer in mice. UV-induced PPARβ/δ activity, which directly stimulated Src expression, increased Src kinase activity and enhanced the EGFR/Erk1/2 signalling pathway, resulting in increased epithelial-to-mesenchymal transition (EMT) marker expression. Consistent with these observations, PPARβ/δ-null mice developed fewer and smaller skin tumours, and a PPARβ/δ antagonist prevented UV-dependent Src stimulation. Furthermore, the expression of PPARβ/δ positively correlated with the expression of SRC and EMT markers in human skin squamous cell carcinoma (SCC), and critically, linear models applied to several human epithelial cancers revealed an interaction between PPARβ/δ and SRC and TGFβ1 transcriptional levels. Taken together, these observations motivate the future evaluation of PPARβ/δ modulators to attenuate the development of several epithelial cancers. PMID:24203162

  12. Proline-rich tyrosine kinase 2 downregulates peroxisome proliferator-activated receptor gamma to promote hypoxia-induced pulmonary artery smooth muscle cell proliferation.

    PubMed

    Bijli, Kaiser M; Kang, Bum-Yong; Sutliff, Roy L; Hart, C Michael

    2016-06-01

    Hypoxia stimulates pulmonary hypertension (PH), in part by increasing the proliferation of human pulmonary artery smooth muscle cells (HPASMCs) via sustained activation of mitogen-activated protein kinase, extracellular signal-regulated kinases 1 and 2 (ERK 1/2), and nuclear factor-kappa B (NF-κB); elevated expression of NADPH oxidase 4 (Nox4); and downregulation of peroxisome proliferator-activated receptor gamma (PPARγ) levels. However, the upstream mediators that control these responses remain largely unknown. We hypothesized that proline-rich tyrosine kinase 2 (Pyk2) plays a critical role in the mechanism of hypoxia-induced HPASMC proliferation. To test this hypothesis, HPASMCs were exposed to normoxia or hypoxia (1% O2) for 72 hours. Hypoxia activated Pyk2 (detected as Tyr402 phosphorylation), and inhibition of Pyk2 with small interfering RNA (siRNA) or tyrphostin A9 attenuated hypoxia-induced HPASMC proliferation. Pyk2 inhibition attenuated ERK 1/2 activation as early as 24 hours after the onset of hypoxia, suggesting a proximal role for Pyk2 in this response. Pyk2 inhibition also attenuated hypoxia-induced NF-κB activation, reduced HPASMC PPARγ messenger RNA levels and activity, and increased NF-κB-mediated Nox4 levels. The siRNA-mediated PPARγ knockdown enhanced Pyk2 activation, whereas PPARγ overexpression reduced Pyk2 activation in HPASMCs, confirming a reciprocal relationship between Pyk2 and PPARγ. Pyk2 depletion also attenuated hypoxia-induced NF-κB p65 activation and reduced PPARγ protein levels in human pulmonary artery endothelial cells. These in vitro findings suggest that Pyk2 plays a central role in the proliferative phenotype of pulmonary vascular wall cells under hypoxic conditions. Coupled with recent reports that hypoxia-induced PH is attenuated in Pyk2 knockout mice, these findings suggest that Pyk2 may represent a novel therapeutic target in PH. PMID:27252847

  13. Proline-rich tyrosine kinase 2 downregulates peroxisome proliferator–activated receptor gamma to promote hypoxia-induced pulmonary artery smooth muscle cell proliferation

    PubMed Central

    2016-01-01

    Abstract Hypoxia stimulates pulmonary hypertension (PH), in part by increasing the proliferation of human pulmonary artery smooth muscle cells (HPASMCs) via sustained activation of mitogen-activated protein kinase, extracellular signal–regulated kinases 1 and 2 (ERK 1/2), and nuclear factor-kappa B (NF-κB); elevated expression of NADPH oxidase 4 (Nox4); and downregulation of peroxisome proliferator–activated receptor gamma (PPARγ) levels. However, the upstream mediators that control these responses remain largely unknown. We hypothesized that proline-rich tyrosine kinase 2 (Pyk2) plays a critical role in the mechanism of hypoxia-induced HPASMC proliferation. To test this hypothesis, HPASMCs were exposed to normoxia or hypoxia (1% O2) for 72 hours. Hypoxia activated Pyk2 (detected as Tyr402 phosphorylation), and inhibition of Pyk2 with small interfering RNA (siRNA) or tyrphostin A9 attenuated hypoxia-induced HPASMC proliferation. Pyk2 inhibition attenuated ERK 1/2 activation as early as 24 hours after the onset of hypoxia, suggesting a proximal role for Pyk2 in this response. Pyk2 inhibition also attenuated hypoxia-induced NF-κB activation, reduced HPASMC PPARγ messenger RNA levels and activity, and increased NF-κB-mediated Nox4 levels. The siRNA-mediated PPARγ knockdown enhanced Pyk2 activation, whereas PPARγ overexpression reduced Pyk2 activation in HPASMCs, confirming a reciprocal relationship between Pyk2 and PPARγ. Pyk2 depletion also attenuated hypoxia-induced NF-κB p65 activation and reduced PPARγ protein levels in human pulmonary artery endothelial cells. These in vitro findings suggest that Pyk2 plays a central role in the proliferative phenotype of pulmonary vascular wall cells under hypoxic conditions. Coupled with recent reports that hypoxia-induced PH is attenuated in Pyk2 knockout mice, these findings suggest that Pyk2 may represent a novel therapeutic target in PH. PMID:27252847

  14. Peroxisome protein import: a complex journey

    PubMed Central

    Baker, Alison; Hogg, Thomas Lanyon; Warriner, Stuart L.

    2016-01-01

    The import of proteins into peroxisomes possesses many unusual features such as the ability to import folded proteins, and a surprising diversity of targeting signals with differing affinities that can be recognized by the same receptor. As understanding of the structure and function of many components of the protein import machinery has grown, an increasingly complex network of factors affecting each step of the import pathway has emerged. Structural studies have revealed the presence of additional interactions between cargo proteins and the PEX5 receptor that affect import potential, with a subtle network of cargo-induced conformational changes in PEX5 being involved in the import process. Biochemical studies have also indicated an interdependence of receptor–cargo import with release of unloaded receptor from the peroxisome. Here, we provide an update on recent literature concerning mechanisms of protein import into peroxisomes. PMID:27284042

  15. Mechanisms underlying skin disorders induced by EGFR inhibitors

    PubMed Central

    Holcmann, Martin; Sibilia, Maria

    2015-01-01

    The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is frequently mutated or overexpressed in a large number of tumors such as carcinomas or glioblastoma. Inhibitors of EGFR activation have been successfully established for the therapy of some cancers and are more and more frequently being used as first or later line therapies. Although the side effects induced by inhibitors of EGFR are less severe than those observed with classic cytotoxic chemotherapy and can usually be handled by out-patient care, they may still be a cause for dose reduction or discontinuation of treatment that can reduce the effectiveness of antitumor therapy. The mechanisms underlying these cutaneous side effects are only partly understood. Important questions, such as the reasons for the correlation between the intensity of the side effects and the efficiency of treatment with EGFR inhibitors, remain to be answered. Optimized adjuvant strategies to accompany anti-EGFR therapy need to be found for optimal therapeutic application and improved quality of life of patients. Here, we summarize current literature on the molecular and cellular mechanisms underlying the cutaneous side effects induced by EGFR inhibitors and provide evidence that keratinocytes are probably the optimal targets for adjuvant therapy aimed at alleviating skin toxicities. PMID:27308503

  16. Enhanced pan-peroxisome proliferator-activated receptor gene and protein expression in adipose tissue of diet-induced obese mice treated with telmisartan.

    PubMed

    Penna-de-Carvalho, Aline; Graus-Nunes, Francielle; Rabelo-Andrade, Júlia; Mandarim-de-Lacerda, Carlos Alberto; Souza-Mello, Vanessa

    2014-12-01

    Telmisartan has previously been used to target obesity, showing peroxisome proliferator-activated receptor (PPAR) β/δ-related effects in white adipose tissue (WAT). We sought to evaluate whether telmisartan enhances gene and protein expression of all PPAR isoforms in WAT and brown adipose tissue (BAT), as well as their downstream effects upon insulin resistance, adipokine profile and adaptive thermogenesis. Male C57BL/6 mice were fed standard chow (SC; 10% lipids) or high-fat diet (HF; 50% lipids) for 10 weeks. Animals were then randomly allocated into the following four groups: SC, SC-T, HF and HF-T. Telmisartan [10 mg (kg diet)(-1)] was administered for 4 weeks in the diet. Animals in the HF group were overweight and exhibited hypertension, insulin resistance, decreased energy expenditure, a pro-inflammatory adipokine profile and abnormal fat pad mass distribution. Animals in the HF group showed decreased expression of PPARα, β/δ and γ in WAT and BAT, resulting in impaired glucose uptake and insufficient thermogenesis. Due to the improvement in the adipokine profile and enhanced insulin sensitivity with adequate insulin-stimulated glucose uptake after treatment with telmisartan, the activation of all PPAR isoforms in WAT was beneficial. In BAT, telmisartan induced sustained sympathetic activation, because the β3-adrenergic receptor was induced by PPARβ/δ, while uncoupling protein 1 was induced by PPARα to promote thermogenesis. Telmisartan exerted anti-obesity effects through higher pan-PPAR gene and protein expression. Upon PPARα, β/δ and γ (pan-PPAR) agonism in adipose tissue of obese mice, telmisartan ameliorates inflammation and insulin resistance, as well as inducing non-shivering thermogenesis. Our results point to new therapeutic targets for the control of obesity and comorbidities through pan-PPAR-related effects. PMID:25326526

  17. 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

  18. Induction of peroxisomes by butyrate-producing probiotics.

    PubMed

    Weng, Huachun; Endo, Kosuke; Li, Jiawei; Kito, Naoko; Iwai, Naoharu

    2015-01-01

    We previously found that peroxisomal biogenesis factor 11a (Pex11a) deficiency is associated with a reduction in peroxisome abundance and impaired fatty acid metabolism in hepatocytes, and results in steatosis. In the present study, we investigated whether butyrate induces Pex11a expression and peroxisome proliferation, and studied its effect on lipid metabolism. C57BL/6 mice fed standard chow or a high-fat diet (HFD) were treated with tributyrin, 4-phelybutyrate acid (4-PBA), or the butyrate-producing probiotics (Clostridium butyricum MIYAIRI 588 [CBM]) plus inulin (dietary fiber), and the body weight, white adipose tissue, serum triglycerides, mRNA expression, and peroxisome abundance were evaluated. Tributyrin or 4-PBA treatment significantly decreased body weight and increased hepatic mRNA expression of peroxisome proliferator-activated receptor-α (PPARα) and Pex11a. In addition, 4-PBA treatment increased peroxisome abundance and the expression of genes involved in peroxisomal fatty acid β-oxidation (acyl-coenzyme A oxidase 1 and hydroxysteroid [17-beta] dehydrogenase 4). CBM and inulin administration reduced adipose tissue mass and serum triglycerides, induced Pex11a, acyl-coenzyme A oxidase 1, and hydroxysteroid (17-beta) dehydrogenase 4 genes, and increased peroxisome abundance in mice fed standard chow or an HFD. In conclusion, elevation of butyrate availability (directly through administration of butyrate or indirectly via administration of butyrate-producing probiotics plus fiber) induces PPARα and Pex11a and the genes involved in peroxisomal fatty acid β-oxidation, increases peroxisome abundance, and improves lipid metabolism. These results may provide a new therapeutic strategy against hyperlipidemia and obesity. PMID:25659146

  19. Protection from noise-induced hearing loss with Src inhibitors.

    PubMed

    Bielefeld, Eric C

    2015-06-01

    Noise-induced hearing loss is a major cause of acquired hearing loss around the world and pharmacological approaches to protecting the ear from noise are under investigation. Noise results in a combination of mechanical and metabolic damage pathways in the cochlea. The Src family of protein tyrosine kinases could be active in both pathways and Src inhibitors have successfully prevented noise-induced cochlear damage and hearing loss in animal models. The long-term goal is to optimize delivery methods into the cochlea to reduce invasiveness and limit side-effects before human clinical testing can be considered. At their current early stage of research investigation, Src inhibitors represent an exciting class of compounds for inclusion in a multifaceted pharmacological approach to protecting the ear from noise. PMID:25637168

  20. Candesartan cilexetil prevents diet-induced insulin resistance via peroxisome proliferator-activated receptor-γ activation in an obese rat model

    PubMed Central

    YAN, WEN-HUA; PAN, CHANG-YU; DOU, JING-TAO; MENG, JUN-HUA; WANG, BAO-AN; MU, YI-MING

    2016-01-01

    Angiotensin II type 1 receptor (AT1R) blockers (ARBs) have been shown to reduce the incidence of type 2 diabetes mellitus; however, the underlying molecular mechanism is unknown. Peroxisome proliferator-activated receptor γ (PPARγ) is the central regulator of insulin and glucose metabolism, which improves insulin sensitivity. Whether candesartan cilexetil, as a prodrug of the AT1R blocker candesartan, has PPARγ-activating properties remains to be elucidated. The aim of the present study was to investigate the effects of oral administration of candesartan cilexetil on glucose tolerance and the actions of PPARγ on liver and adipose tissue in the insulin-resistant obese rat induced by high-fat diet. Animals treated with candesartan cilexetil showed an improved glucose tolerance after oral glucose challenge. Whole-body insulin sensitivity was evaluated using the hyperinsulinemic-euglycemic clamp technique. During high-fat feeding in high-fat diet (HF) rats, the glucose infusion rate (GIR) was 52.3% lower than that in normal chow (NC) rats. However, the GIR was significantly enhanced following candesartan cilexetil treatment. Angiotensin II receptor antagonism also resulted in significant increases in PPARγ protein expression in adipose and liver tissue. These results indicate that PPARγ activation by candesartan cilexetil may provide novel therapeutic options in the treatment of patients with metabolic syndrome. PMID:27347049

  1. 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

  2. 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; 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.

  3. 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.

  4. Effects of Peroxisomal Catalase Inhibition on Mitochondrial Function

    PubMed Central

    Walton, Paul A.; Pizzitelli, Michael

    2012-01-01

    Peroxisomes produce hydrogen peroxide as a metabolic by-product of their many oxidase enzymes, but contain catalase that breaks down hydrogen peroxide in order to maintain the organelle’s oxidative balance. It has been previously demonstrated that, as cells age, catalase is increasingly absent from the peroxisome, and resides instead as an unimported tetrameric molecule in the cell cytosol; an alteration that is coincident with increased cellular hydrogen peroxide levels. As this process begins in middle-passage cells, we sought to determine whether peroxisomal hydrogen peroxide could contribute to the oxidative damage observed in mitochondria in late-passage cells. Early-passage human fibroblasts (Hs27) treated with aminotriazole (3-AT), an irreversible catalase inhibitor, demonstrated decreased catalase activity, increased levels of cellular hydrogen peroxide, protein carbonyls, and peroxisomal numbers. This treatment increased mitochondrial reactive oxygen species levels, and decreased the mitochondrial aconitase activity by ∼85% within 24 h. In addition, mitochondria from 3-AT treated cells show a decrease in inner membrane potential. These results demonstrate that peroxisome-derived oxidative imbalance may rapidly impair mitochondrial function, and considering that peroxisomal oxidative imbalance begins to occur in middle-passage cells, supports the hypothesis that peroxisomal oxidant release occurs upstream of, and contributes to, the mitochondrial damage observed in aging cells. PMID:22536190

  5. Pulmonary Administration of GW0742, a High-Affinity Peroxisome Proliferator-Activated Receptor Agonist, Repairs Collapsed Alveoli in an Elastase-Induced Mouse Model of Emphysema.

    PubMed

    Ozawa, Chihiro; Horiguchi, Michiko; Akita, Tomomi; Oiso, Yuki; Abe, Kaori; Motomura, Tomoki; Yamashita, Chikamasa

    2016-01-01

    Pulmonary emphysema is a disease in which lung alveoli are irreversibly damaged, thus compromising lung function. Our previous study revealed that all-trans-retinoic acid (ATRA) induces the differentiation of human lung alveolar epithelial type 2 progenitor cells and repairs the alveoli of emphysema model mice. ATRA also reportedly has the ability to activate peroxisome proliferator-activated receptor (PPAR) β/δ. A selective PPARβ/δ ligand has been reported to induce the differentiation of human keratinocytes during wound repair. Here, we demonstrate that treatment using a high-affinity PPARβ/δ agonist, GW0742, reverses the lung tissue damage induced by elastase in emphysema-model mice and improves respiratory function. Mice treated with elastase, which collapsed their alveoli, were then treated with either 10% dimethyl sulfoxide (DMSO) in saline (control group) or GW0742 (1.0 mg/kg twice a week) by pulmonary administration. Treatment with GW0742 for 2 weeks increased the in vivo expression of surfactant proteins A and D, which are known alveolar type II epithelial cell markers. GW0742 treatment also shortened the average distance between alveolar walls in the lungs of emphysema model mice, compared with a control group treated with 10% DMSO in saline. Treatment with GW0742 for 3 weeks also improved tissue elastance (cm H2O/mL), as well as the ratio of the forced expiratory volume in the first 0.05 s to the forced vital capacity (FEV 0.05/FVC). In each of these experiments, GW0742 treatment reversed the damage caused by elastase. In conclusion, PPARβ/δ agonists are potential therapeutic agents for pulmonary emphysema. PMID:27150147

  6. 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

  7. Rosiglitazone, a Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, Attenuates Inflammation Via NF-κB 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)-γ 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 20 ml 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-κB-p65 and IκBα 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-IκBα 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-κB-p65 and IκBα without decreasing CD40 mRNA expression. Rosiglitazone has a protective effect in peritonitis, simultaneously decreasing NF-κB phosphorylation, suggesting that NF-κB signaling pathway mediated peritoneal inflammation induced by LPS. PPAR-γ might be considered a potential therapeutic target against peritonitis. PMID:26047949

  8. Neuron-Specific Deletion of Peroxisome Proliferator-Activated Receptor Delta (PPARδ) in Mice Leads to Increased Susceptibility to Diet-Induced Obesity

    PubMed Central

    Kocalis, Heidi E.; Turney, Maxine K.; Printz, Richard L.; Laryea, Gloria N.; Muglia, Louis J.; Davies, Sean S.; Stanwood, Gregg D.; McGuinness, Owen P.; Niswender, Kevin D.

    2012-01-01

    Central nervous system (CNS) lipid accumulation, inflammation and resistance to adipo-regulatory hormones, such as insulin and leptin, are implicated in the pathogenesis of diet-induced obesity (DIO). Peroxisome proliferator-activated receptors (PPAR α, δ, γ) are nuclear transcription factors that act as environmental fatty acid sensors and regulate genes involved in lipid metabolism and inflammation in response to dietary and endogenous fatty acid ligands. All three PPAR isoforms are expressed in the CNS at different levels. Recent evidence suggests that activation of CNS PPARα and/or PPARγ may contribute to weight gain and obesity. PPARδ is the most abundant isoform in the CNS and is enriched in the hypothalamus, a region of the brain involved in energy homeostasis regulation. Because in peripheral tissues, expression of PPARδ increases lipid oxidative genes and opposes inflammation, we hypothesized that CNS PPARδ protects against the development of DIO. Indeed, genetic neuronal deletion using Nes-Cre loxP technology led to elevated fat mass and decreased lean mass on low-fat diet (LFD), accompanied by leptin resistance and hypothalamic inflammation. Impaired regulation of neuropeptide expression, as well as uncoupling protein 2, and abnormal responses to a metabolic challenge, such as fasting, also occur in the absence of neuronal PPARδ. Consistent with our hypothesis, KO mice gain significantly more fat mass on a high-fat diet (HFD), yet are surprisingly resistant to diet-induced elevations in CNS inflammation and lipid accumulation. We detected evidence of upregulation of PPARγ and target genes of both PPARα and PPARγ, as well as genes of fatty acid oxidation. Thus, our data reveal a previously underappreciated role for neuronal PPARδ in the regulation of body composition, feeding responses, and in the regulation of hypothalamic gene expression. PMID:22916190

  9. ACE inhibitor potentiation of bradykinin-induced venoconstriction

    PubMed Central

    Hecker, Markus; Blaukat, Andree; Bara, Agnieszka T; Müller-Esterl, Werner; Busse, Rudi

    1997-01-01

    Angiotensin-converting enzyme (ACE) inhibitors exert their cardiovascular effects not only by preventing the formation of angiotensin II (AII), but also by promoting the accumulation of bradykinin in or at the vessel wall. In addition, certain ACE inhibitors have been shown to augment the vasodilator response to bradykinin, presumably by an interaction at the level of the B2 receptor. We have investigated whether this is a specific effect of the ACE inhibitor class of compounds in isolated endothelium-denuded segments of the rabbit jugular vein where bradykinin elicits a constrictor response which is exclusively mediated by activation of the B2 receptor. Moexiprilat and ramiprilat (⩽ 3 nM) enhanced the constrictor response to bradykinin three to four fold. Captopril and enalaprilat were less active by approximately one and quinaprilat by two orders of magnitude. Moexiprilat and ramiprilat, on the other hand, had no effect on the constrictor response to AII or the dilator response to acetylcholine. The bradykinin-potentiating effect of the ACE inhibitors was not mimicked by inhibitors of amino-, carboxy-, metallo- or serine peptidases or the synthetic ACE substrate, hippuryl-L-histidyl-L-leucine, at a concentration which almost abolished the residual ACE activity in the vessel wall. In contrast, angiotensin-(1–7) (10 μM), an angiotensin I metabolite, significantly enhanced the constrictor response to bradykinin. Ramiprilat did not alter the binding of [3H]-bradykinin to a membrane fraction prepared from endothelium-denuded rabbit jugular veins or to cultured fibroblasts, and there was no ACE inhibitor-sensitive, bradykinin-induced cleavage of the B2 receptor in cultured endothelial cells. These findings demonstrate that ACE inhibitors selectively potentiate the B2 receptor-mediated vascular effects of bradykinin. Their relative efficacy appears to be independent of their ACE-inhibiting properties and might be related to differences in molecule structure

  10. 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. PMID:26408931

  11. 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

  12. 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 β-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 β-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 β-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 β-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

  13. Vascular and Central Activation of Peroxisome Proliferator-Activated Receptor-β Attenuates Angiotensin II-Induced Hypertension: Role of RGS-5.

    PubMed

    Romero, Miguel; Jiménez, Rosario; Toral, Marta; León-Gómez, Elvira; Gómez-Gúzman, Manuel; Sánchez, Manuel; Zarzuelo, María José; Rodríguez-Gómez, Isabel; Rath, Geraldine; Tamargo, Juan; Pérez-Vizcaíno, Francisco; Dessy, Chantal; Duarte, Juan

    2016-07-01

    Activation of peroxisome proliferator-activated receptor-β/δ (PPARβ) lowers blood pressure in genetic and mineralocorticoid-induced hypertension. Regulator of G-protein-coupled receptor signaling 5 (RGS5) protein, which interferes in angiotensin II (AngII) signaling, is a target gene to PPARβ The aim of the present study was to examine whether PPARβ activation in resistance arteries and brain tissues prevents the elevated blood pressure in AngII-induced hypertension and evaluate the role of RGS5 in this effect. C57BL/6J male mice were divided into five groups (control mice, PPARβ agonist [4-[[[2-[3-Fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy]acetic acid (GW0742)-treated mice AngII-infused mice, GW0742-treated AngII-infused mice, and AngII-infused mice treated with GW0742 plus PPARβ antagonist 3-[[[2-Methoxy-4-(phenylamino)phenyl]amino]sulfonyl]-2-thiophenecarboxylic acid methyl ester (GSK0660)) and were followed for 3 weeks. GW0742 prevented the increase in both arterial blood pressure and plasma noradrenaline levels and the higher reduction of blood pressure after ganglionic blockade, whereas it reduced the mesenteric arterial remodeling and the hyper-responsiveness to vasoconstrictors (AngII and endothelin-1) in AngII-infused mice. These effects were accompanied by an inhibition of NADPH oxidase expression and activity in the brain. Gene expression profiling revealed a marked loss of brainstem and vascular RGS5 in AngII-infused mice, which was restored by GW0742. GW0742-induced effects were abolished by GSK0660. Small interfering RNA targeting RGS5 caused augmented contractile response to AngII in resistance mesenteric arteries and blunted the inhibitory effect of GW0742 on this response. In conclusion, GW0742 exerted antihypertensive effects, restoring sympathetic tone and vascular structure and function in AngII-infused mice by PPARβ activation in brain and vessels inhibiting AngII signaling as a result of RGS5

  14. Role of the PAS1 gene of Pichia pastoris in peroxisome biogenesis

    PubMed Central

    1994-01-01

    Several groups have reported the cloning and sequencing of genes involved in the biogenesis of yeast peroxisomes. Yeast strains bearing mutations in these genes are unable to grow on carbon sources whose metabolism requires peroxisomes, and these strains lack morphologically normal peroxisomes. We report the cloning of Pichia pastoris PAS1, the homologue (based on a high level of protein sequence similarity) of the Saccharomyces cerevisiae PAS1. We also describe the creation and characterization of P. pastoris pas1 strains. Electron microscopy on the P. pastoris pas1 cells revealed that they lack morphologically normal peroxisomes, and instead contain membrane-bound structures that appear to be small, mutant peroxisomes, or "peroxisome ghosts." These "ghosts" proliferated in response to induction on peroxisome-requiring carbon sources (oleic acid and methanol), and they were distributed to daughter cells. Biochemical analysis of cell lysates revealed that peroxisomal proteins are induced normally in pas1 cells. Peroxisome ghosts from pas1 cells were purified on sucrose gradients, and biochemical analysis showed that these ghosts, while lacking several peroxisomal proteins, did import varying amounts of several other peroxisomal proteins. The existence of detectable peroxisome ghosts in P. pastoris pas1 cells, and their ability to import some proteins, stands in contrast with the results reported by Erdmann et al. (1991) for the S. cerevisiae pas1 mutant, in which they were unable to detect peroxisome-like structures. We discuss the role of PAS1 in peroxisome biogenesis in light of the new information regarding peroxisome ghosts in pas1 cells. PMID:7962088

  15. 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

  16. Dual targeting of peroxisomal proteins

    PubMed Central

    Ast, Julia; Stiebler, Alina C.; Freitag, Johannes; Bölker, 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

  17. Peroxisomal metabolism and oxidative stress.

    PubMed

    Nordgren, Marcus; Fransen, Marc

    2014-03-01

    Peroxisomes are ubiquitous and multifunctional organelles that are primarily known for their role in cellular lipid metabolism. As many peroxisomal enzymes catalyze redox reactions as part of their normal function, these organelles are also increasingly recognized as potential regulators of oxidative stress-related signaling pathways. This in turn suggests that peroxisome dysfunction is not only associated with rare inborn errors of peroxisomal metabolism, but also with more common age-related diseases such as neurodegeneration, type 2 diabetes, and cancer. This review intends to provide a comprehensive picture of the complex role of mammalian peroxisomes in cellular redox metabolism. We highlight how peroxisomal metabolism may contribute to the bioavailability of important mediators of oxidative stress, with particular emphasis on reactive oxygen species. In addition, we review the biological properties of peroxisome-derived signaling messengers and discuss how these molecules may mediate various biological responses. Furthermore, we explore the emerging concepts that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. This is particularly relevant to the observed demise of peroxisome function which accompanies cellular senescence, organismal aging, and age-related diseases. PMID:23933092

  18. 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.

  19. Formation of Tankyrase Inhibitor-Induced Degradasomes Requires Proteasome Activity

    PubMed Central

    Pedersen, Nina Marie; Thorvaldsen, Tor Espen; Schultz, Sebastian Wolfgang; Wenzel, Eva Maria; Stenmark, Harald

    2016-01-01

    In canonical Wnt signaling, the protein levels of the key signaling mediator β-catenin are under tight regulation by the multimeric destruction complex that mediates proteasomal degradation of β-catenin. In colorectal cancer, destruction complex activity is often compromised due to mutations in the multifunctional scaffolding protein Adenomatous Polyposis Coli (APC), leading to a stabilization of β-catenin. Recently, tankyrase inhibitors (TNKSi), a novel class of small molecule inhibitors, were shown to re-establish a functional destruction complex in APC-mutant cancer cell lines by stabilizing AXIN1/2, whose protein levels are usually kept low via poly(ADP-ribosyl)ation by the tankyrase enzymes (TNKS1/2). Surprisingly, we found that for the formation of the morphological correlates of destruction complexes, called degradasomes, functional proteasomes are required. In addition we found that AXIN2 is strongly upregulated after 6 h of TNKS inhibition. The proteasome inhibitor MG132 counteracted TNKSi-induced degradasome formation and AXIN2 stabilization, and this was accompanied by reduced transcription of AXIN2. Mechanistically we could implicate the transcription factor FoxM1 in this process, which was recently shown to be a transcriptional activator of AXIN2. We observed a substantial reduction in TNKSi-induced stabilization of AXIN2 after siRNA-mediated depletion of FoxM1 and found that proteasome inhibition reduced the active (phosphorylated) fraction of FoxM1. This can explain the decreased protein levels of AXIN2 after MG132 treatment. Our findings have implications for the design of in vitro studies on the destruction complex and for clinical applications of TNKSi. PMID:27482906

  20. 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

  1. Phosphatidylcholine Supply to Peroxisomes of the Yeast Saccharomyces cerevisiae.

    PubMed

    Flis, Vid V; Fankl, Ariane; 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

  2. 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

  3. Degradation of plant peroxisomes by autophagy

    PubMed Central

    Lee, Han Nim; Kim, Jimi; Chung, Taijoon

    2014-01-01

    Peroxisomes play a critical role in many metabolic pathways during the plant life cycle. It has been proposed that the transition between different types of peroxisomes involves the degradation of obsolete peroxisomal enzymes via proteolytic activities in the peroxisome matrix, the cytosol, or the vacuole. Forward and reverse genetic studies recently provided evidence for autophagic degradation of peroxisomes in the vacuole of Arabidopsis seedlings. Here, we briefly review a model of pexophagy, or selective autophagy of peroxisomes, in plant cells. PMID:24782878

  4. No peroxisome is an island — Peroxisome contact sites☆

    PubMed Central

    Shai, Nadav; Schuldiner, Maya; Zalckvar, Einat

    2016-01-01

    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. PMID:26384874

  5. 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. PMID:26384874

  6. 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.

  7. 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

  8. Peroxisome Metabolism and Cellular Aging

    PubMed Central

    Titorenko, Vladimir I.; Terlecky, Stanley R.

    2010-01-01

    The essential role of peroxisomes in fatty acid oxidation, anaplerotic metabolism, and hydrogen peroxide turnover is well established. Recent findings suggest these and other related biochemical processes governed by the organelle may also play a critical role in regulating cellular aging. The goal of this review is to summarize and integrate into a model, the evidence that peroxisome metabolism actually helps define the replicative and chronological age of a eukaryotic cell. In this model, peroxisomal reactive oxygen species (ROS) are seen as altering organelle biogenesis and function, and eliciting changes in the dynamic communication networks that exist between peroxisomes and other cellular compartments. At low levels, peroxisomal ROS activate an anti-aging program in the cell; at concentrations beyond a specific threshold, a pro-aging course is triggered. PMID:21083858

  9. 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

  10. Pex19p, a Farnesylated Protein Essential for Peroxisome Biogenesis

    PubMed Central

    Götte, Klaudia; Girzalsky, Wolfgang; Linkert, Michael; Baumgart, Evelyn; Kammerer, Stefan; Kunau, Wolf-Hubert; Erdmann, Ralf

    1998-01-01

    We report the identification and molecular characterization of Pex19p, an oleic acid-inducible, farnesylated protein of 39.7 kDa that is essential for peroxisome biogenesis in Saccharomyces cerevisiae. Cells lacking Pex19p are characterized by the absence of morphologically detectable peroxisomes and mislocalization of peroxisomal matrix proteins to the cytosol. The human HK33 gene product was identified as the putative human ortholog of Pex19p. Evidence is provided that farnesylation of Pex19p takes place at the cysteine of the C-terminal CKQQ amino acid sequence. Farnesylation of Pex19p was shown to be essential for the proper function of the protein in peroxisome biogenesis. Pex19p was shown to interact with Pex3p in vivo, and this interaction required farnesylation of Pex19p. PMID:9418908

  11. Selective Serotonin–norepinephrine Reuptake Inhibitors-induced Takotsubo Cardiomyopathy

    PubMed Central

    Vasudev, Rahul; Rampal, Upamanyu; Patel, Hiten; Patel, Kunal; Bikkina, Mahesh; Shamoon, Fayez

    2016-01-01

    Context: Takotsubo translates to “octopus pot” in Japanese. Takotsubo cardiomyopathy (TTC) is characterized by a transient regional systolic dysfunction of the left ventricle. Catecholamine excess is the one most studied and favored theories explaining the pathophysiology of TTC. Case Report: We present the case of a 52-year-old Hispanic female admitted for venlafaxine-induced TTC with a review literature on all the cases of Serotonin–norepinephrine reuptake inhibitors (SNRI)-associated TTC published so far. Conclusion: SNRI inhibit the reuptake of catecholamines into the presynaptic neuron, resulting in a net gain in the concentration of epinephrine and serotonin in the neuronal synapses and causing iatrogenic catecholamine excess, ultimately leading to TTC. PMID:27583240

  12. Inhibitors of Histone Deacetylases Attenuate Noise-Induced Hearing Loss.

    PubMed

    Chen, Jun; Hill, Kayla; Sha, Su-Hua

    2016-08-01

    Loss of auditory sensory hair cells is the major pathological feature of noise-induced hearing loss (NIHL). Currently, no established clinical therapies for prevention or amelioration of NIHL are available. The absence of treatments is due to our lack of a comprehensive understanding of the molecular mechanisms underlying noise-induced damage. Our previous study indicates that epigenetic modification of histones alters hair cell survival. In this study, we investigated the effect of noise exposure on histone H3 lysine 9 acetylation (H3K9ac) in the inner ear of adult CBA/J mice and determined if inhibition of histone deacetylases by systemic administration of suberoylanilide hydroxamic acid (SAHA) could attenuate NIHL. Our results showed that H3K9ac was decreased in the nuclei of outer hair cells (OHCs) and marginal cells of the stria vascularis in the basal region after exposure to a traumatic noise paradigm known to induce permanent threshold shifts (PTS). Consistent with these results, levels of histone deacetylases 1, 2, and 3 (HDAC1, HDAC2 and HDAC3) were increased predominately in the nuclei of cochlear cells. Silencing of HDAC1, HDAC2, or HDAC3 with siRNA reduced the expression of the target HDAC in OHCs, but did not attenuate noise-induced PTS, whereas treatment with the pan-HDAC inhibitor SAHA, also named vorinostat, reduced OHC loss, and attenuated PTS. These findings suggest that histone acetylation is involved in the pathogenesis of noise-induced OHC death and hearing loss. Pharmacological targeting of histone deacetylases may afford a strategy for protection against NIHL. PMID:27095478

  13. MG132, a proteasome inhibitor, induces apoptosis in tumor cells.

    PubMed

    Guo, Na; Peng, Zhilan

    2013-03-01

    The balance between cell proliferation and apoptosis is critical for normal development and for the maintenance of homeostasis in adult organisms. Disruption of this balance has been implicated in a large number of disease processes, ranging from autoimmunity and neurodegenerative disorders to cancer. The ubiquitin-proteasome pathway, responsible for mediating the majority of intracellular proteolysis, plays a crucial role in the regulation of many normal cellular processes, including the cell cycle, differentiation and apoptosis. Apoptosis in cancer cells is closely connected with the activity of ubiquitin-proteasome pathway. The peptide-aldehyde proteasome inhibitor MG132 (carbobenzoxyl-L-leucyl-L-leucyl-L-leucine) induces the apoptosis of cells by a different intermediary pathway. Although the pathway of induction of apoptosis is different, it plays a crucial role in anti-tumor treatment. There are many cancer-related molecules in which the protein levels present in cells are regulated by a proteasomal pathway; for example, tumor inhibitors (P53, E2A, c-Myc, c-Jun, c-Fos), transcription factors (transcription factor nuclear factor-kappa B, IκBα, HIFI, YYI, ICER), cell cycle proteins (cyclin A and B, P27, P21, IAP1/3), MG132 induces cell apoptosis through formation of reactive oxygen species or the upregulation and downregulation of these factors, which is ultimately dependent upon the activation of the caspase family of cysteine proteases. In this article we review the mechanism of the induction of apoptosis in order to provide information required for research. PMID:22897979

  14. 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...

  15. Formation of the peroxisome lumen is abolished by loss of Pichia pastoris Pas7p, a zinc-binding integral membrane protein of the peroxisome.

    PubMed Central

    Kalish, J E; Theda, C; Morrell, J C; Berg, J M; Gould, S J

    1995-01-01

    We have cloned and sequenced PAS7, a gene required for peroxisome assembly in the yeast Pichia pastoris. The product of this gene, Pas7p, is a member of the C3HC4 superfamily of zinc-binding proteins. Point mutations that alter conserved residues of the C3HC4 motif abolish PAS7 activity and reduce zinc binding, suggesting that Pas7p binds zinc in vivo and that zinc binding is essential for PAS7 function. As with most pas mutants, pas7 cells exhibit a pronounced deficiency in import of peroxisomal matrix proteins that contain either the type 1 peroxisomal targeting signal (PTS1) or the type 2 PTS (PTS2). However, while other yeast and mammalian pas mutants accumulate ovoid, vesicular peroxisomal intermediates, loss of Pas7p leads to accumulation of membrane sheets and vesicles which lack a recognizable lumen. Thus, Pas7p appears to be essential for protein translocation into peroxisomes as well as formation of the lumen of the organelle. Consistent with these data, we find that Pas7p is an integral peroxisomal membrane protein which is entirely resistant to exogenous protease and thus appears to reside completely within the peroxisome. Our observations suggest that the function of Pas7p defines a previously unrecognized step in peroxisome assembly: formation of the peroxisome lumen. Furthermore, because the peroxisomal intermediates in the pas7 delta mutant proliferate in response to peroxisome-inducing environmental conditions, we conclude that Pas7p is not required for peroxisome proliferation. PMID:7565793

  16. 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.

  17. Human disorders of peroxisome metabolism and biogenesis.

    PubMed

    Waterham, Hans R; Ferdinandusse, Sacha; Wanders, Ronald J A

    2016-05-01

    Peroxisomes are dynamic organelles that play an essential role in a variety of cellular catabolic and anabolic metabolic pathways, including fatty acid alpha- and beta-oxidation, and plasmalogen and bile acid synthesis. Defects in genes encoding peroxisomal proteins can result in a large variety of peroxisomal disorders either affecting specific metabolic pathways, i.e., the single peroxisomal enzyme deficiencies, or causing a generalized defect in function and assembly of peroxisomes, i.e., peroxisome biogenesis disorders. In this review, we discuss the clinical, biochemical, and genetic aspects of all human peroxisomal disorders currently known. PMID:26611709

  18. Valproic Acid and Other HDAC Inhibitors Induce Microglial Apoptosis and Attenuate Lipopolysaccharide- induced Dopaminergic Neurotoxicity

    PubMed Central

    Chen, Po See; Wang, Chao-Chuan; Bortner, Carl D.; Peng, Giia-Sheun; Wu, Xuefei; Pang, Hao; Lu, Ru-Band; Gean, Po-Wu; Chuang, De-Maw; Hong, Jau-Shyong

    2009-01-01

    Valproic acid (VPA), a widely prescribed drug for seizures and bipolar disorder, has been shown to be an inhibitor of histone deacetylase (HDAC). Our previous study has demonstrated that VPA pretreatment reduces lipopolysaccharide (LPS)-induced dopaminergic (DA) neurotoxicity through the inhibition of microglia over-activation. The aim of this study was to determine the mechanism underlying VPA-induced attenuation of microglia over-activation. Other HDAC inhibitors (HDACIs) were compared with VPA for their effects on microglial activity. We found that VPA induced apoptosis of microglia cells in a time and concentration-dependent manner. VPA-treated microglial cells showed typical apoptotic hallmarks including phosphatidylserine externalization, chromatin condensation and DNA fragmentation. Further studies revealed that trichostatin A (TSA) and sodium butyrate (SB), two structurally dissimilar HDACIs, also induced microglial apoptosis. The apoptosis of microglia was accompanied by the disruption of mitochondrial membrane potential and the enhancement of acetylation levels of the histone H3 protein. Moreover, pretreatment with SB or TSA caused a robust decrease in LPS-induced pro-inflammatory responses and protected DA neurons from damage in mesencephalic neuron-glia cultures. Taken together, our results shed light on a novel mechanism whereby HDACIs induce neuroprotection and underscore the potential utility of HDACIs in preventing inflammation-related neurodegenerative disorders such as Parkinson’s disease. PMID:17850978

  19. Inhibitors

    MedlinePlus

    ... Community Counts Blood Safety Inhibitors Articles & Key Findings Free Materials Videos Starting the Conversation Playing it Safe A Look at Hemophilia Joint Range of Motion My Story Links to Other Websites ...

  20. 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. PMID:26453805

  1. 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

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

    SciTech Connect

    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. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.

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

    PubMed Central

    Motley, Alison M.; Galvin, Paul C.; Ekal, Lakhan; Nuttall, James M.

    2015-01-01

    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

  4. The Pichia pastoris PER6 gene product is a peroxisomal integral membrane protein essential for peroxisome biogenesis and has sequence similarity to the Zellweger syndrome protein PAF-1.

    PubMed Central

    Waterham, H R; de Vries, Y; Russel, K A; Xie, W; Veenhuis, M; Cregg, J M

    1996-01-01

    We report the cloning of PER6, a gene essential for peroxisome biogenesis in the methylotrophic yeast Pichia pastoris. The PER6 sequence predicts that its product Per6p is a 52-kDa polypeptide with the cysteine-rich C3HC4 motif. Per6p has significant overall sequence similarity with the human peroxisome assembly factor PAF-1, a protein that is defective in certain patients suffering from the peroxisomal disorder Zellweger syndrome, and with car1, a protein required for peroxisome biogenesis and caryogamy in the filamentous fungus Podospora anserina. In addition, the C3HC4 motif and two of the three membrane-spanning segments predicted for Per6p align with the C3HC4 motifs and the two membrane-spanning segments predicted for PAF-1 and car1. Like PAF-1, Per6p is a peroxisomal integral membrane protein. In methanol- or oleic acid-induced cells of per6 mutants, morphologically recognizable peroxisomes are absent. Instead, peroxisomal remnants are observed. In addition, peroxisomal matrix proteins are synthesized but located in the cytosol. The similarities between Per6p and PAF-1 in amino acid sequence and biochemical properties, and between mutants defective in their respective genes, suggest that Per6p is the putative yeast homolog of PAF-1. PMID:8628321

  5. 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

  6. 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. PMID:26434997

  7. Endogenous and endobiotic induced reactive oxygen species formation by isolated hepatocytes.

    PubMed

    Siraki, Arno G; Pourahmad, Jalal; Chan, Tom S; Khan, Sumsullah; O'Brien, Peter J

    2002-01-01

    The rat hepatocyte catalyzed oxidation of 2',7'-dichlorofluorescin to form the fluorescent 2,7'-dichlorofluorescein was used to measure endogenous and xenobiotic-induced reactive oxygen species (ROS) formation by intact isolated rat hepatocytes. Various oxidase substrates and inhibitors were then used to identify the intracellular oxidases responsible. Endogenous ROS formation was markedly increased in catalase-inhibited or GSH-depleted hepatocytes, and was inhibited by ROS scavengers or desferoxamine. Endogenous ROS formation was also inhibited by cytochrome P450 inhibitors, but was not affected by oxypurinol, a xanthine oxidase inhibitor, or phenelzine, a monoamine oxidase inhibitor. Mitochondrial respiratory chain inhibitors or hypoxia, on the other hand, markedly increased ROS formation before cytotoxicity ensued. Furthermore, uncouplers of oxidative phosphorylation inhibited endogenous ROS formation. This suggests endogenous ROS formation can largely be attributed to oxygen reduction by reduced mitochondrial electron transport components and reduced cytochrome P450 isozymes. Addition of monoamine oxidase substrates increased antimycin A-resistant respiration and ROS formation before cytotoxicity ensued. Addition of peroxisomal substrates also increased antimycin A-resistant respiration but they were less effective at inducing ROS formation and were not cytotoxic. However, peroxisomal substrates readily induced ROS formation and were cytotoxic towards catalase-inhibited hepatocytes, which suggests that peroxisomal catalase removes endogenous H(2)O(2) formed in the peroxisomes. Hepatocyte catalyzed dichlorofluorescin oxidation induced by oxidase substrates, e.g., benzylamine, was correlated with the cytotoxicity induced in catalase-inhibited hepatocytes. PMID:11755311

  8. Behavioral destabilization induced by the selective serotonin reuptake inhibitor fluoxetine

    PubMed Central

    2011-01-01

    Background Selective serotonin reuptake inhibitors (SSRIs) are widely used to treat mood and anxiety disorders. However, neuronal bases for both beneficial and adverse effects of SSRIs remain poorly understood. We have recently shown that the SSRI fluoxetine can reverse the state of maturation of hippocampal granule cells in adult mice. The granule cell "dematuration" is induced in a large population of granule cells, and greatly changes functional and physiological properties of these cells. Here we show that this unique form of neuronal plasticity is correlated with a distinct change in behavior of mice. Results We chronically treated adult male mice with fluoxetine, and examined its effect on several forms of behavior of mice. During fluoxetine treatments, mice showed a marked increase in day-to-day fluctuations of home cage activity levels that was characterized by occasional switching between hypoactivity and hyperactivity within a few days. This destabilized cage activity was accompanied by increased anxiety-related behaviors and could be observed up to 4 weeks after withdrawal from fluoxetine. As reported previously, the granule cell dematuration by fluoxetine includes a reduction of synaptic facilitation at the granule cell output, mossy fiber, synapse to the juvenile level. Mossy fiber synaptic facilitation examined electrophysiologically in acute hippocampal slices also remained suppressed after fluoxetine withdrawal and significantly correlated with the fluctuation of cage activity levels in individual mice. Furthermore, in mice lacking the 5-HT4 receptor, in which the granule cell dematuration has been shown to be attenuated, fluoxetine had no significant effect on the fluctuation of cage activity levels. Conclusions Our results demonstrate that the SSRI fluoxetine can induce marked day-to-day changes in activity levels of mice in the familiar environment, and that the dematuration of the hippocampal granule cells is closely associated with the

  9. Evaluation of aspirin metabolites as inhibitors of hypoxia-inducible factor hydroxylases.

    PubMed

    Lienard, Benoit M; Conejo-García, Ana; Stolze, Ineke; Loenarz, Christoph; Oldham, Neil J; Ratcliffe, Peter J; Schofield, Christopher J

    2008-12-21

    Known and potential aspirin metabolites were evaluated as inhibitors of oxygen-sensing hypoxia-inducible transcription factor (HIF) hydroxylases; some of the metabolites were found to stabilise HIF-alpha in cells. PMID:19048166

  10. 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.…

  11. 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. PMID:26851075

  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. PMID:26775584

  13. 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

  14. 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. PMID:26348128

  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. 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

  17. 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

  18. 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

  19. Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-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)γ ligand ciglitazone and novel PPARγ 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 PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation in a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-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 PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.

  20. Salicylic Acid Inhibits Synthesis of Proteinase Inhibitors in Tomato Leaves Induced by Systemin and Jasmonic Acid.

    PubMed Central

    Doares, S. H.; Narvaez-Vasquez, J.; Conconi, A.; Ryan, C. A.

    1995-01-01

    Salicylic acid (SA) and acetylsalicylic acid (ASA), previously shown to inhibit proteinase inhibitor synthesis induced by wounding, oligouronides (H.M. Doherty, R.R. Selvendran, D.J. Bowles [1988] Physiol Mol Plant Pathol 33: 377-384), and linolenic acid (H. Pena-Cortes, T. Albrecht, S. Prat, E.W. Weiler, L. Willmitzer [1993] Planta 191: 123-128), are shown here to be potent inhibitors of systemin-induced and jasmonic acid (JA)-induced synthesis of proteinase inhibitor mRNAs and proteins. The inhibition by SA and ASA of proteinase inhibitor synthesis induced by systemin and JA, as well as by wounding and oligosaccharide elicitors, provides further evidence that both oligosaccharide and polypeptide inducer molecules utilize the octadecanoid pathway to signal the activation of proteinase inhibitor genes. Tomato (Lycopersicon esculentum) leaves were pulse labeled with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the inhibitory effects of SA are shown to be specific for the synthesis of a small number of JA-inducible proteins that includes the proteinase inhibitors. Previous results have shown that SA inhibits the conversion of 13S-hydroperoxy linolenic acid to 12-oxo-phytodienoic acid, thereby inhibiting the signaling pathway by blocking synthesis of JA. Here we report that the inhibition of synthesis of proteinase inhibitor proteins and mRNAs by SA in both light and darkness also occurs at a step in the signal transduction pathway, after JA synthesis but preceding transcription of the inhibitor genes. PMID:12228577

  1. 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.

  2. DPP IV inhibitor blocks mescaline-induced scratching and amphetamine-induced hyperactivity in mice.

    PubMed

    Lautar, Susan L; Rojas, Camilo; Slusher, Barbara S; Wozniak, Krystyna M; Wu, Ying; Thomas, Ajit G; Waldon, Daniel; Li, William; Ferraris, Dana; Belyakov, Sergei

    2005-06-28

    Dipeptidyl peptidase IV (DPP IV) is a ubiquitous membrane-bound enzyme that cleaves the two N-terminal amino acids from peptides with a proline or alanine residue in the second position from the amino end. Potential substrates for DPP IV include several neuropeptides, suggesting a role for DPP IV in neurological processes. We have developed a potent DPP IV inhibitor (IC50 = 30 nM), 1-(2-amino-3-methyl-butyryl)-azetidine-2-carbonitrile (AMAC), which has shown efficacy in two established models of psychosis: mescaline-induced scratching and amphetamine-induced hyperactivity. In the mescaline-induced scratching model, AMAC treatment before mescaline administration reduced the number of scratching paroxysms by 68% (P < 0.01). The compound showed a dose-dependent effect, inhibiting significantly at 6, 20 and 60 mg/kg (37%, 39% and 68%, respectively). In the amphetamine-induced hyperactivity model, 50 and 60 mg/kg AMAC, given before injection of amphetamine, significantly reduced hyper-locomotion by 65% and 76%, respectively. Additionally, AMAC showed no significant activity in binding assays for 20 receptors thought to be involved in the pathology of schizophrenia, including dopamine, serotonin and glutamate. A structurally similar analog, 1-(2-dimethylamino-3-methyl-butyryl)-azetidine-2-carbonitrile (DAMAC), that does not inhibit DPP IV, was inactive in both models. Taken together, these data suggest that the antipsychotic effects of AMAC are the result of DPP IV inhibition. PMID:15925329

  3. Specific MAPK inhibitors prevent hyperglycemia-induced renal diseases in type 1 diabetic mouse model.

    PubMed

    Hong, Zhe; Hong, Zongyuan; Wu, Denglong; Nie, Hezhongrong

    2016-08-01

    Mitogen-activated protein kinase (MAPK) and renin-angiotensin system (RAS) play critical roles in the process of renal diseases, but their interaction has not been comprehensively discussed. In the present studies, we investigated the renoprotective effects of MPAK inhibitors on renal diseases in type 1 diabetic mouse model, and clarify the crosstalk among MAPK signaling. Type 1 diabetic mouse model was established in male C57BL/6 J mice, and treated with or without 10 mg/kg MAPK blockers, including ERK inhibitor PD98059, p38 inhibitor SB203850, and JNK inhibitor SP600125 for four weeks. Hyperglycemia induced renal injuries, but treating them with MAPK inhibitors significantly decreased glomerular volume and glycogen in renal tissues. Although slightly changed body weight and fasting blood glucose levels, MAPK inhibitors attenuated blood urea nitrogen, urea protein, and microalbuminuria. Administration also reduced the diabetes-induced RAS activation, including angiotensin II converting enzyme (c) and Ang II, which contributed to its renal protective effects in the diabetic mice. In addition, the anti-RAS of MAPK inhibitor treatment markedly reduced gene expression of tumor necrosis factor-α, interleukin-6, and inducible nitric oxide synthase, fibrotic accumulation, and transforming growth factor-β1 levels in renal tissues. Furthermore, chemical inhibitors and genetic siRNA results identified the crosstalk among the three MAPK signaling, and proved JNK signaling played a critical role in MAPK-mediated ACE pathway in hyperglycemia state. Collectively, these results support the therapeutic effects of MAPK-specific inhibitors, especially JNK inactivation, on hyperglycemia-induced renal damages. PMID:27389030

  4. Variability of Voriconazole Trough Levels in Haematological Patients: Influence of Comedications with cytochrome P450(CYP) Inhibitors and/or with CYP Inhibitors plus CYP Inducers.

    PubMed

    Cojutti, Piergiorgio; Candoni, Anna; Forghieri, Fabio; Isola, Miriam; Zannier, Maria Elena; Bigliardi, Sara; Luppi, Mario; Fanin, Renato; Pea, Federico

    2016-06-01

    Voriconazole plasma exposure greatly varies among haematological patients. The purpose of this study was to identify the magnitude of influence of comedications with CYP inhibitors and/or with CYP inhibitors plus CYP inducers on voriconazole trough level (Cmin ). Voriconazole Cmin was retrospectively assessed among haematological patients who underwent therapeutic drug monitoring (TDM). Univariate and multivariate linear mixed-effect regression analyses were performed to identify the independent predictors of normalized Cmin . Of the 83 included patients, 35 had comedications with CYP inhibitors (omeprazole or pantoprazole) and 21 with CYP inhibitors (omeprazole or pantoprazole) plus CYP inducers (methylprednisolone, dexamethasone, phenobarbital, rifampin or carbamazepine). Median Cmin value (n = 199) was 2.4 mg/L with a wide range of distribution (<0.2-13.5 mg/L). Median (IQR) normalized voriconazole Cmin value was significantly higher in the presence of CYP inhibitors (4.20 mg/L, 3.23-5.51 mg/L) than either in the absence of interacting cotreatments (2.55 mg/L, 1.54-3.47 mg/L) or in the presence of CYP inhibitors plus CYP inducers (2.16 mg/L, 1.19-3.09 mg/L). The presence of CYP inhibitors was highly significantly associated with Cmin >5.5 mg/L (OR: 23.22, 95% CI: 3.01-179.09, p = 0.003). No significant association emerged when CYP inhibitors were coadministered with CYP inducers (OR: 3.53, 95% CI: 0.36-34.95, p = 0.280). The amount of expected Cmin increase was significantly influenced by both the type and the dose of the administered proton pump inhibitor. The study highlights that the benefit from TDM of voriconazole may be maximal in those patients who are cotreated with CYP inhibitors and/or with CYP inhibitors plus CYP inducers, especially when receiving proton pump inhibitors (PPIs) at very high dosages intravenously. PMID:26572687

  5. Activating effect of benzbromarone, a uricosuric drug, on peroxisome proliferator-activated receptors.

    PubMed

    Kunishima, Chiyoko; Inoue, Ikuo; Oikawa, Toshihiro; Nakajima, Hiromu; Komoda, Tsugikazu; Katayama, Shigehiro

    2007-01-01

    Benzbromarone, a uricosuric drug, reportedly causes hepatic hypertrophy accompanied by proliferation of peroxisomes in rats. To elucidate the mechanisms underlying induction of peroxisome proliferation by benzbromarone, we examined binding affinity for peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (PPARgamma), and effects on the binding activity of PPARs with peroxisome proliferation-responsive element (PPRE) and expression of the PPARs target protein. Binding affinity of benzbromarone for PPARalpha and PPARgamma was examined by reporter gene assay. Binding activity of PPARs with PPRE was determined by electric mobility shift assay, and expression of lipoprotein lipase (LPL) and acyl-CoA synthetase (ACS) by Western blot method. Benzbromarone displayed affinity for PPARalpha and PPARgamma, and promoted binding of PPARs to PPRE. Furthermore, cultured cells with benzbromarone added showed upregulated expression of LPL and ACS. These results suggest that benzbromarone induces peroxisome proliferation in hepatocytes by binding to PPARs, and controls expression of proteins related to lipid metabolism. PMID:18274627

  6. Activating Effect of Benzbromarone, a Uricosuric Drug, on Peroxisome Proliferator-Activated Receptors

    PubMed Central

    Kunishima, Chiyoko; Inoue, Ikuo; Oikawa, Toshihiro; Nakajima, Hiromu; Komoda, Tsugikazu; Katayama, Shigehiro

    2007-01-01

    Benzbromarone, a uricosuric drug, reportedly causes hepatic hypertrophy accompanied by proliferation of peroxisomes in rats. To elucidate the mechanisms underlying induction of peroxisome proliferation by benzbromarone, we examined binding affinity for peroxisome proliferator-activated receptor α (PPARα) and γ (PPARγ), and effects on the binding activity of PPARs with peroxisome proliferation-responsive element (PPRE) and expression of the PPARs target protein. Binding affinity of benzbromarone for PPARα and PPARγ was examined by reporter gene assay. Binding activity of PPARs with PPRE was determined by electric mobility shift assay, and expression of lipoprotein lipase (LPL) and acyl-CoA synthetase (ACS) by Western blot method. Benzbromarone displayed affinity for PPARα and PPARγ, and promoted binding of PPARs to PPRE. Furthermore, cultured cells with benzbromarone added showed upregulated expression of LPL and ACS. These results suggest that benzbromarone induces peroxisome proliferation in hepatocytes by binding to PPARs, and controls expression of proteins related to lipid metabolism. PMID:18274627

  7. 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.

  8. Peroxisomes are platforms for cytomegalovirus’ evasion from the cellular immune response

    PubMed Central

    Magalhães, Ana Cristina; Ferreira, Ana Rita; Gomes, Sílvia; Vieira, Marta; Gouveia, Ana; Valença, Isabel; Islinger, Markus; Nascimento, Rute; Schrader, Michael; Kagan, Jonathan C.; Ribeiro, Daniela

    2016-01-01

    The human cytomegalovirus developed distinct evasion mechanisms from the cellular antiviral response involving vMIA, a virally-encoded protein that is not only able to prevent cellular apoptosis but also to inhibit signalling downstream from mitochondrial MAVS. vMIA has been shown to localize at mitochondria and to trigger their fragmentation, a phenomenon proven to be essential for the signalling inhibition. Here, we demonstrate that vMIA is also localized at peroxisomes, induces their fragmentation and inhibits the peroxisomal-dependent antiviral signalling pathway. Importantly, we demonstrate that peroxisomal fragmentation is not essential for vMIA to specifically inhibit signalling downstream the peroxisomal MAVS. We also show that vMIA interacts with the cytoplasmic chaperone Pex19, suggesting that the virus has developed a strategy to highjack the peroxisomal membrane proteins’ transport machinery. Furthermore, we show that vMIA is able to specifically interact with the peroxisomal MAVS. Our results demonstrate that peroxisomes constitute a platform for evasion of the cellular antiviral response and that the human cytomegalovirus has developed a mechanism by which it is able to specifically evade the peroxisomal MAVS-dependent antiviral signalling. PMID:27181750

  9. Peroxisomes are platforms for cytomegalovirus' evasion from the cellular immune response.

    PubMed

    Magalhães, Ana Cristina; Ferreira, Ana Rita; Gomes, Sílvia; Vieira, Marta; Gouveia, Ana; Valença, Isabel; Islinger, Markus; Nascimento, Rute; Schrader, Michael; Kagan, Jonathan C; Ribeiro, Daniela

    2016-01-01

    The human cytomegalovirus developed distinct evasion mechanisms from the cellular antiviral response involving vMIA, a virally-encoded protein that is not only able to prevent cellular apoptosis but also to inhibit signalling downstream from mitochondrial MAVS. vMIA has been shown to localize at mitochondria and to trigger their fragmentation, a phenomenon proven to be essential for the signalling inhibition. Here, we demonstrate that vMIA is also localized at peroxisomes, induces their fragmentation and inhibits the peroxisomal-dependent antiviral signalling pathway. Importantly, we demonstrate that peroxisomal fragmentation is not essential for vMIA to specifically inhibit signalling downstream the peroxisomal MAVS. We also show that vMIA interacts with the cytoplasmic chaperone Pex19, suggesting that the virus has developed a strategy to highjack the peroxisomal membrane proteins' transport machinery. Furthermore, we show that vMIA is able to specifically interact with the peroxisomal MAVS. Our results demonstrate that peroxisomes constitute a platform for evasion of the cellular antiviral response and that the human cytomegalovirus has developed a mechanism by which it is able to specifically evade the peroxisomal MAVS-dependent antiviral signalling. PMID:27181750

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

    PubMed

    Kemmerer, Marina; Finkernagel, Florian; Cavalcante, Marcela Frota; Abdalla, Dulcineia Saes Parra; Müller, Rolf; Brüne, 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 δ (PPARδ) also affects fatty acid metabolism, stimulating the expression of genes involved in FAO. To question the interplay of AMPK and PPARδ in human macrophages we transduced primary human macrophages with lentiviral particles encoding for the constitutively active AMPKα1 catalytic subunit, followed by microarray expression analysis after treatment with the PPARδ agonist GW501516. Microarray analysis showed that co-activation of AMPK and PPARδ 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 AMPKγ1 regulatory subunit carrying an activating R70Q mutation. The pharmacological AMPK activator A-769662 increased expression of several FAO genes in a PPARδ- 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

  11. 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; Müller, Rolf; Brüne, 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 δ (PPARδ) also affects fatty acid metabolism, stimulating the expression of genes involved in FAO. To question the interplay of AMPK and PPARδ in human macrophages we transduced primary human macrophages with lentiviral particles encoding for the constitutively active AMPKα1 catalytic subunit, followed by microarray expression analysis after treatment with the PPARδ agonist GW501516. Microarray analysis showed that co-activation of AMPK and PPARδ 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 AMPKγ1 regulatory subunit carrying an activating R70Q mutation. The pharmacological AMPK activator A-769662 increased expression of several FAO genes in a PPARδ- 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

  12. Nutritionally induced changes in the peroxisome proliferator-activated receptor-alpha gene expression in liver of suckling rats are dependent on insulinaemia.

    PubMed

    Panadero, M; Vidal, H; Herrera, E; Bocos, C

    2001-10-15

    It was previously found that the expression of peroxisome proliferator-activated receptor-alpha (PPARalpha) was markedly augmented in the liver of suckling rats, in comparison to the fetuses and most notably to adult rats and it paralleled similar changes in hepatic lipid concentration. To determine whether these changes could be related to the high lipid content of the maternal milk and/or to hormonal status, the role of changes in nutrient availability and in plasma insulin concentration on liver expression during the perinatal stage in vivo in the rat was studied. When suckling rats were weaned on day 17, instead of on day 20, the level of hepatic PPARalpha mRNA decreased earlier than in rats weaned later. When 10-day-old rats were force-fed with either glucose or Intralipid or a combination of both diets, it was found that, at similar low levels of plasma insulin, a high level of FFA stimulated PPARalpha expression, whereas, at similar high plasma FFA concentrations, an elevated insulin level attenuated the increase in PPARalpha expression. It is proposed that both the high lipid intake and decreased plasma insulin level are responsible for the high PPARalpha expression detected in rat neonates. PMID:11594732

  13. ACBD2/ECI2-Mediated Peroxisome-Mitochondria Interactions in Leydig Cell Steroid Biosynthesis.

    PubMed

    Fan, Jinjiang; Li, Xinlu; Issop, Leeyah; Culty, Martine; Papadopoulos, Vassilios

    2016-07-01

    Fatty acid metabolism and steroid biosynthesis are 2 major pathways shared by peroxisomes and mitochondria. Both organelles are in close apposition to the endoplasmic reticulum, with which they communicate via interorganelle membrane contact sites to promote cellular signaling and the exchange of ions and lipids. To date, no convincing evidence of the direct contact between peroxisomes and mitochondria was reported in mammalian cells. Hormone-induced, tightly controlled steroid hormone biosynthesis requires interorganelle interactions. Using immunofluorescent staining and live-cell imaging, we found that dibutyryl-cAMP treatment of MA-10 mouse tumor Leydig cells rapidly induces peroxisomes to approach mitochondria and form peroxisome-mitochondrial contact sites/fusion, revealed by the subcellular distribution of the endogenous acyl-coenzyme A-binding domain (ACBD)2/ECI2 isoform A generated by alternative splicing, and further validated using a proximity ligation assay. This event occurs likely via a peroxisome-like structure, which is mediated by peroxisomal and mitochondrial matrix protein import complexes: peroxisomal import receptor peroxisomal biogenesis factor 5 (PEX5), and the mitochondrial import receptor subunit translocase of outer mitochondrial membrane 20 homolog (yeast) protein. Similar results were obtained using the mLTC-1 mouse tumor Leydig cells. Ectopic expression of the ACBD2/ECI2 isoform A in MA-10 cells led to increased basal and hormone-stimulated steroid formation, indicating that ACBD2/ECI2-mediated peroxisomes-mitochondria interactions favor in the exchange of metabolites and/or macromolecules between these 2 organelles in support of steroid biosynthesis. Considering the widespread occurrence of the ACBD2/ECI2 protein, we propose that this protein might serve as a tool to assist in understanding the contact between peroxisomes and mitochondria. PMID:27167610

  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. PMID:26686055

  15. Localization of peroxisomal matrix proteins by photobleaching

    SciTech Connect

    Buch, Charlotta; 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.

  16. The role of peroxisome-proliferator-activating receptor gamma agonists: rosiglitazone and 15-deoxy-delta12,14-prostaglandin J2 in chronic experimental cyclosporine A-induced nephrotoxicity.

    PubMed

    Korolczuk, A; Maciejewski, M; Smolen, A; Dudka, J; Czechowska, G; Widelska, I

    2014-12-01

    Cyclosporine A(CsA) is an immunosuppressor frequently used in the transplant surgery and in the treatment of autoimmune diseases. The therapeutic benefits of CsA are often limited by it's main side effect-nephrotoxicity. Mechanisms of chronic CsA- induced renal damage include: activation of renin-angiotensin-aldosterone system, upregulation of transforming growth factor beta (TGF-β), oxidative stress. This study was undertaken to investigate the protective effect of the peroxisome-proliferator-activated receptors gamma (PPARs-γ) agonists: rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2 (PGDJ2), against CsA-induced kidney injury in male Wistar rats. CsA was administered subcutaneously at a dose of 15 mg/kg/day for 28 days. Both PPAR-γ agonists were given for 28 days 0.5 hour before the administration of CsA. Rosiglitazone was administered orally at a dose of 8 mg/kg/day and PGDJ2 was given intraperitoneally at a dose of 30 μg/kg/day. CsA induced renal failure was evidenced by increased serum levels of urea, uric acid and creatinine. Serum concentrations of GSH and GSSG, lipid peroxidation products as well as NAD+/NADH, NADP+/NADPH and ADP/ATP ratios showed, that CsA induced oxidative stress and evoked an imbalanced red-ox state in the kidney. Light and electron microscope studies showed degenerative changes within renal tubules with damage to their mitochondria, interstitial fibrosis and arteriolopathy. Immunohistochemical expression of profibrotic TGF-β was assessed. The biochemical and morphological changes induced by CsA were limited by administration of both rosiglitazone and PGDJ2. Ultrastructural examination of renal tubular epithelial cells showed marked improvement within mitochondria. Our results indicate that both PPAR-γ agonists used in the experiment may play an important role in protecting against CsA-induced damage in the kidney. PMID:25554991

  17. Peroxisome proliferator-activated receptor gamma up-regulates the Bcl-2 anti-apoptotic protein in neurons and induces mitochondrial stabilization and protection against oxidative stress and apoptosis.

    PubMed

    Fuenzalida, Karen; Quintanilla, Rodrigo; Ramos, Patricio; Piderit, Daniela; Fuentealba, Rodrigo A; Martinez, Gabriela; Inestrosa, Nibaldo C; Bronfman, Miguel

    2007-12-21

    Peroxisome proliferator-activated receptor gamma (PPARgamma) has been proposed as a therapeutic target for neurodegenerative diseases because of its anti-inflammatory action in glial cells. However, PPARgamma agonists preventbeta-amyloid (Abeta)-induced neurodegeneration in hippocampal neurons, and PPARgamma is activated by the nerve growth factor (NGF) survival pathway, suggesting a neuroprotective anti-inflammatory independent action. Here we show that the PPARgamma agonist rosiglitazone (RGZ) protects hippocampal and dorsal root ganglion neurons against Abeta-induced mitochondrial damage and NGF deprivation-induced apoptosis, respectively, and promotes PC12 cell survival. In neurons and in PC12 cells RGZ protective effects are associated with increased expression of the Bcl-2 anti-apoptotic protein. NGF-differentiated PC12 neuronal cells constitutively overexpressing PPARgamma are resistant to Abeta-induced apoptosis and morphological changes and show functionally intact mitochondria and no increase in reactive oxygen species when challenged with up to 50 microM H2O2. Conversely, cells expressing a dominant negative mutant of PPARgamma show increased Abeta-induced apoptosis and disruption of neuronal-like morphology and are highly sensitive to oxidative stress-induced impairment of mitochondrial function. Cells overexpressing PPARgamma present a 4- to 5-fold increase in Bcl-2 protein content, whereas in dominant negative PPARgamma-expressing cells, Bcl-2 is barely detected. Bcl-2 knockdown by small interfering RNA in cells overexpressing PPARgamma results in increased sensitivity to Abeta and oxidative stress, further suggesting that Bcl-2 up-regulation mediates PPARgamma protective effects. PPARgamma prosurvival action is independent of the signal-regulated MAPK or the Akt prosurvival pathways. Altogether, these data suggest that PPARgamma supports survival in neurons in part through a mechanism involving increased expression of Bcl-2. PMID:17965419

  18. 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.

  19. Hypothermia-induced hyperphosphorylation: a new model to study tau kinase inhibitors

    PubMed Central

    Bretteville, Alexis; Marcouiller, François; Julien, Carl; El Khoury, Noura B.; Petry, Franck R.; Poitras, Isabelle; Mouginot, Didier; Lévesque, Georges; Hébert, Sébastien S.; Planel, Emmanuel

    2012-01-01

    Tau hyperphosphorylation is one hallmark of Alzheimer's disease (AD) pathology. Pharmaceutical companies have thus developed kinase inhibitors aiming to reduce tau hyperphosphorylation. One obstacle in screening for tau kinase inhibitors is the low phosphorylation levels of AD-related phospho-epitopes in normal adult mice and cultured cells. We have shown that hypothermia induces tau hyperphosphorylation in vitro and in vivo. Here, we hypothesized that hypothermia could be used to assess tau kinase inhibitors efficacy. Hypothermia applied to models of biological gradual complexity such as neuronal-like cells, ex vivo brain slices and adult non-transgenic mice leads to tau hyperphosphorylation at multiple AD-related phospho-epitopes. We show that Glycogen Synthase Kinase-3 inhibitors LiCl and AR-A014418, as well as roscovitine, a cyclin-dependent kinase 5 inhibitor, decrease hypothermia-induced tau hyperphosphorylation, leading to different tau phosphorylation profiles. Therefore, we propose hypothermia-induced hyperphosphorylation as a reliable, fast, convenient and inexpensive tool to screen for tau kinase inhibitors. PMID:22761989

  20. 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

  1. The class-I HDAC inhibitor MGCD0103 induces apoptosis in Hodgkin lymphoma cell lines and synergizes with proteasome inhibitors by an HDAC6-independent mechanism

    PubMed Central

    Buglio, Daniela; Mamidipudi, Vidya; Khaskhely, Noor M.; Brady, Helen; Heise, Carla; Besterman, Jeffrey; Martell, Robert E.; MacBeth, Kyle; Younes, Anas

    2011-01-01

    Summary Inhibition of histone deacetylase 6 (HDAC6)-dependent aggresome function by pan HDAC inhibitors was recently reported to be a key mechanism underlying the synergistic activity between proteasome inhibitors and HDAC inhibitors in a variety of tumour types. Because these combinations induce significant thrombocytopenia in vivo, we examined whether less toxic, isotype-selective HDAC inhibitors may still synergize with proteasome inhibitors, and if so, by what mechanisms. Here, we showed that the class I HDAC inhibitor, MGCD0103, has a potent antiproliferative activity in Hodgkin lymphoma (HL) cell lines. Furthermore, MGCD0103 induced tumour necrosis factor α (TNF-α) expression and secretion, which was associated with nuclear factor (NF)-κB activation. Selective inhibition of TNF- α expression by short interfering mRNA, or inhibition of MGCD0103-induced NF-kB activation by proteasome inhibitors enhanced MGCD0103-induced cell death. Thus, our results demonstrate that MGCD0103 may synergize with proteasome inhibitors by HDAC6-independent mechanisms, providing mechanistic rationale for exploring this potentially less toxic combination for the treatment of lymphoma. PMID:20880107

  2. 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

  3. Cancerous inhibitor of protein phosphatase 2A determines bortezomib-induced apoptosis in leukemia cells

    PubMed Central

    Liu, Chun-Yu; Shiau, Chung-Wai; Kuo, Hsin-Yu; Huang, Hsiang-Po; Chen, Ming-Huang; Tzeng, Cheng-Hwai; Chen, Kuen-Feng

    2013-01-01

    The multiple cellular targets affected by proteasome inhibition implicate a potential role for bortezomib, a first-in-class proteasome inhibitor, in enhancing antitumor activities in hematologic malignancies. Here, we examined the antitumor activity and drug targets of bortezomib in leukemia cells. Human leukemia cell lines were used for in vitro studies. Drug efficacy was evaluated by apoptosis assays and associated molecular events assessed by Western Blot. Gene silencing was performed by small interference RNA. Drug was tested in vivo in xenograft models of human leukemia cell lines and in primary leukemia cells. Clinical samples were assessed by immunohistochemical staining. Bortezomib differentially induced apoptosis in leukemia cells that was independent of its proteasome inhibition. Cancerous inhibitor of protein phosphatase 2A, a cellular inhibitor of protein phosphatase 2A, mediated the apoptotic effect of bortezomib. Bortezomib increased protein phosphatase 2A activity in sensitive leukemia cells (HL-60 and KG-1), but not in resistant cells (MOLT-3 and K562). Bortezomib’s downregulation of cancerous inhibitor of protein phosphatase 2A and phospho-Akt correlated with its drug sensitivity. Furthermore, cancerous inhibitor of protein phosphatase 2A negatively regulated protein phosphatase 2A activity. Ectopic expression of CIP2A up-regulated phospho-Akt and protected HL-60 cells from bortezomib-induced apoptosis, whereas silencing CIP2A overcame the resistance to bortezomib-induced apoptosis in MOLT3 and K562 cells. Importantly, bortezomib exerted in vivo antitumor activity in HL-60 xenografted tumors and induced cell death in some primary leukemic cells. Cancerous inhibitor of protein phosphatase 2A was expressed in leukemic blasts from bone marrow samples. Cancerous inhibitor of protein phosphatase 2A plays a major role in mediating bortezomib-induced apoptosis in leukemia cells. PMID:22983581

  4. Activation of peroxisome proliferator-activated receptor α ameliorates perfluorododecanoic acid-induced production of reactive oxygen species in rat liver.

    PubMed

    Liu, Hui; Zhang, Hongxia; Cui, Ruina; Guo, Xuejiang; Wang, Dazhi; Dai, Jiayin

    2016-06-01

    Perfluorododecanoic acid (PFDoA) is a ubiquitous environmental pollutant known to cause hepatocellular hypertrophy; however, the mechanisms of hepatotoxicity remain poorly understood. In this study, male rats were exposed to 0, 0.05, 0.2 and 0.5 mg/kg/day of PFDoA for 110 days. After two-dimensional differential gel electrophoresis and MALDI-TOF/TOF analysis, 73 differentially expressed proteins involved in lipid metabolism, inflammation, stress response and other functions were successfully identified. Among them, six significantly changed proteins (CTE1, MTE1, HADHA, ECH1, ALDH2 and CPS1) were found to be regulated by peroxisome proliferator-activated receptor alpha (PPARα). The anti-oxidant enzyme activity assays of superoxide dismutase and glutathione peroxidase and the content of thiobarbituric acid-reactive substances in the liver implied that PFDoA caused oxidative stress. The mRNA levels of PPARα in rat primary hepatocytes were knocked down by lentivirus-mediated RNAi. Furthermore, targeted protein levels of CTE1 and MTE1 were down-regulated, while those of HADHA, ALDH2 and CPS1 were up-regulated. After PFDoA exposure, however, the targeted protein levels of CTE1 and ALDH2 increased compared with those of the knockdown untreated group. The reactive oxygen species (ROS) content in rat hepatocytes assayed by flow cytometry significantly increased in the PPARα knockdown groups, consistent with the PPARα antagonist GW6471- and agonist WY14643-treated groups. These results strongly suggested that PPARα played an important role in suppressing ROS content in hepatocytes following PFDoA exposure. PMID:26168851

  5. MEK1/2 inhibitors induce interleukin-5 expression in mouse macrophages and lymphocytes.

    PubMed

    Li, Xiaoju; Cao, Xingyue; Zhang, Xiaomeng; Kang, Yanhua; Zhang, Wenwen; Yu, Miao; Ma, Chuanrui; Han, Jihong; Duan, Yajun; Chen, Yuanli

    2016-05-13

    Uptake of oxidized low-density lipoprotein (oxLDL) by macrophages facilitates the formation of foam cells, the prominent part of atherosclerotic lesions. Interleukin-5 (IL-5) is a cytokine regulating interactions between immune cells. It also activates the production of T15/EO6 IgM antibodies in B-1 cells, which can bind oxLDL thereby demonstrating anti-atherogenic properties. We previously reported that inhibition of extracellular signal-regulated kinases 1 and 2 (ERK1/2) by mitogen-activated protein kinase kinases 1/2 (MEK1/2) inhibitors can reduce atherosclerosis. In this study, we determined the effects of MEK1/2 inhibitors on IL-5 production both in vitro and in vivo. In vitro, MEK1/2 inhibitors (PD98059 and U0126) substantially inhibited phosphorylation of MEK1/2 and ERK1/2. Associated with inhibition of ERK1/2 phosphorylation both in vitro and in vivo, MEK1/2 inhibitors induced IL-5 protein expression in macrophages (RAW macrophages and peritoneal macrophages) and lymphocytes (EL-4 cells). In vivo, administration of mice with MEK1/2 inhibitors increased serum IL-5 levels, and IL-5 protein expression in mouse spleen and liver. At the mechanistic level, we determined that MEK1/2 inhibitors activated IL-5 mRNA expression and IL-5 promoter activity in the liver X receptor (LXR) dependent manner indicating the induction of IL-5 transcription. In addition, we determined that MEK1/2 inhibitors enhanced IL-5 protein stability. Taken together, our study demonstrates that MEK1/2 inhibitors induce IL-5 production which suggests another anti-atherogenic mechanism of MEK1/2 inhibitors. PMID:27045084

  6. Autophagic degradation of peroxisomes in mammals

    PubMed Central

    Katarzyna, Zientara-Rytter; Suresh, Subramani

    2016-01-01

    Peroxisomes are essential organelles required for proper cell function in all eukaryotic organisms. They participate in a wide range of cellular processes including the metabolism of lipids and generation, as well as detoxification, of hydrogen peroxide. Therefore, peroxisome homeostasis, manifested by the precise and efficient control of peroxisome number and functionality, must be tightly regulated in response to environmental changes. Due to the existence of many physiological disorders and diseases associated with peroxisome homeostasis imbalance, the dynamics of peroxisomes have been widely examined. The increasing volume of reports demonstrating significant involvement of the autophagy machinery in peroxisome removal leads us to summarize current knowledge of peroxisome degradation in mammalian cells. In this review we present current models of peroxisome degradation. We particularly focus on pexophagy - the selective clearance of peroxisomes through autophagy. We also critically discuss concepts of peroxisome recognition for pexophagy, including signaling and selectivity factors. Finally, we present examples of the pathological effects of pexophagy dysfunction and suggest promising future directions. PMID:27068951

  7. Proteasome inhibitors attenuated cholesterol-induced cardiac hypertrophy in H9c2 cells.

    PubMed

    Lee, Hyunjung; Park, Jinyoung; Kim, Eunice EunKyeong; Yoo, Young Sook; Song, Eun Joo

    2016-05-01

    The Ubiquitin proteasome system (UPS) plays roles in protein degradation, cell cycle control, and growth and inflammatory cell signaling. Dysfunction of UPS in cardiac diseases has been seen in many studies. Cholesterol acts as an inducer of cardiac hypertrophy. In this study, the effect of proteasome inhibitors on the cholesterol-induced hypertrophic growth in H9c2 cells is examined in order to observe whether UPS is involved in cardiac hypertrophy. The treatment of proteasome inhibitors MG132 and Bortezomib markedly reduced cellular surface area and mRNA expression of β-MHC in cholesterol-induced cardiac hypertrophy. In addition, activated AKT and ERK were significantly attenuated by MG132 and Bortezomib in cholesterol- induced cardiac hypertrophy. We demonstrated that cholesterol- induced cardiac hypertrophy was suppressed by proteasome inhibitors. Thus, regulatory mechanism of cholesterol- induced cardiac hypertrophy by proteasome inhibitors may provide a new therapeutic strategy to prevent the progression of heart failure. [BMB Reports 2016; 49(5): 270-275]. PMID:26592933

  8. Lipopolysaccharide-Related Stimuli Induce Expression of the Secretory Leukocyte Protease Inhibitor, a Macrophage-Derived Lipopolysaccharide Inhibitor

    PubMed Central

    Jin, Fenyu; Nathan, Carl F.; Radzioch, Danuta; Ding, Aihao

    1998-01-01

    Mouse secretory leukocyte protease inhibitor (SLPI) was recently characterized as a lipopolysaccharide (LPS)-induced product of macrophages that antagonizes their LPS-induced activation of NF-κB and production of NO and tumor necrosis factor (TNF) (F. Y. Jin, C. Nathan, D. Radzioch, and A. Ding, Cell 88:417–426, 1997). To better understand the role of SLPI in innate immune and inflammatory responses, we examined the kinetics of SLPI expression in response to LPS, LPS-induced cytokines, and LPS-mimetic compounds. SLPI mRNA was detectable in macrophages by Northern blot analysis within 30 min of exposure to LPS but levels peaked only at 24 to 36 h and remained elevated at 72 h. Despite the slowly mounting and prolonged response, early expression of SLPI mRNA was cycloheximide resistant. Two LPS-induced proteins—interleukin-10 (IL-10) and IL-6—also induced SLPI, while TNF and IL-1β did not. The slow attainment of maximal induction of SLPI by LPS in vitro was mimicked by infection with Pseudomonas aeruginosa in vivo, where SLPI expression in the lung peaked at 3 days. Two LPS-mimetic molecules—taxol from yew bark and lipoteichoic acid (LTA) from gram-positive bacterial cell walls—also induced SLPI. Transfection of macrophages with SLPI inhibited their LTA-induced NO production. An anti-inflammatory role for macrophage-derived SLPI seems likely based on SLPI’s slowly mounting production in response to constituents of gram-negative and gram-positive bacteria, its induction both as a direct response to LPS and as a response to anti-inflammatory cytokines induced by LPS, and its ability to suppress the production of proinflammatory products by macrophages stimulated with constituents of both gram-positive and gram-negative bacteria. PMID:9596701

  9. Salicylates inhibit PAF-acether-induced rat paw oedema when cyclooxygenase inhibitors are ineffective.

    PubMed

    Cordeiro, R S; Silva, P M; Martins, M A; Vargaftig, B B

    1986-11-01

    The cyclooxygenase inhibitors indomethacin, piroxicam, ibuprofen, naproxen and flurbiprofen failed to block rat paw oedema induced by PAF-acether, whereas aspirin and sodium salicylate were effective. Two mixed cyclooxygenase and lipoxygenase inhibitors NDGA, BW 755C and dexamethasone reduced oedema in a dose - dependently. The selective PAF-acether antagonist, BN 52021, was effective against PAF-acether at 5 - 20 mg/kg. The lipoxygenase derivates may be involved in paw oedema induced by PAF-acether in the rat and the inhibition produced by aspirin and by sodium salicylate should involve mechanisms other than the cyclooxygenase pathway. PMID:3103172

  10. Icatibant in the Treatment of Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

    PubMed Central

    Crooks, Neil H.; Patel, Jaimin; Diwakar, Lavanya; Smith, Fang Gao

    2014-01-01

    We describe the case of a 75-year-old woman who presented with massive tongue and lip swelling secondary to angiotensin-converting enzyme inhibitor-induced angioedema. An awake fibre-optic intubation was performed because of impending airway obstruction. As there was no improvement in symptoms after 72 hours, the selective bradykinin B2 receptor antagonist icatibant (Firazyr) was administered and the patient's trachea was successfully extubated 36 hours later. To our knowledge this is the first documented case of icatibant being used for the treatment of angiotensin-converting enzyme inhibitor-induced angioedema in the United Kingdom and represents a novel therapeutic option in its management. PMID:25328718

  11. Microtubule inhibitors block the morphological changes induced in Drosophila blood cells by a parasitoid wasp factor.

    PubMed

    Rizki, R M; Rizki, T M

    1990-03-15

    The shape change of Drosophila melanogaster blood cells (lamellocytes) from discoidal to bipolar that is caused by a factor from the female parasitoid Leptopilina heterotoma is blocked by the tubulin inhibitors vinblastine and vincristine in vitro. The actin inhibitor, cytochalasin B, causes arborization of Drosophila lamellocytes and acts synergistically with the wasp factor to alter lamellocyte morphology. Lamellocyte aborization induced by cytochalasin B is blocked by simultaneous treatment with vinblastine. These observations indicate that the changes in lamellocyte shape induced by both the wasp factor and cytochalasin B require microtubule assembly. PMID:2311722

  12. 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

  13. Reduced expression of peroxisome-proliferator activated receptor gamma coactivator-1α enhances α-synuclein oligomerization and down regulates AKT/GSK3β signaling pathway in human neuronal cells that inducibly express α-synuclein

    PubMed Central

    Ebrahim, Abdul Shukkur; Ko, Li-wen; Yen, Shu-Hui

    2010-01-01

    Intracellular accumulation of filamentous α-synuclein (α-Syn) aggregates to form Lewy bodies is a pathologic hallmark of Parkinson’s disease. To determine whether mitochondrial impairment plays a role in accumulation of α-Syn oligomer, we used 3D5 cell culture model of human neuronal type whereby conditional overexpression of wild-type α-Syn via the tetracycline off (TetOff) induction mechanism results in formation of inclusions that exhibit many characteristics of Lewy bodies. In the present study, we compromised mitochondrial function in 3D5 cells by using shRNA to knockdown peroxisome-proliferator activated receptor gamma coactivator-1α (PGC-1α), a key regulator of mitochondrial biogenesis and cellular energy metabolism and found that PGC-1α suppression at both protein and mRNA levels results in α-Syn accumulation (i.e. monomeric and oligomeric species in the TetOff-induced cells and monomeric only in the non-induced). These changes were accompanied with reduced mitochondrial potential as well as decreased levels of AKT, GSK3β (total and Ser9-phosphorylated) and p53 that are important for cell survival. The extent to which these proteins decreased following PGC-1α knockdown, in contrast to what was demonstrable with the viability assay, is greater in the induced than the non-induced. Together these findings indicate that such knockdown increases the propensity to accumulate α-Syn oligomers, but the accumulation appears to have very little toxic impact to the neuronal cells. PMID:20178833

  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. Inhibitors that stabilize a closed RAF kinase domain conformation induce dimerization

    PubMed Central

    Lavoie, Hugo; Thevakumaran, Neroshan; Gavory, Gwenaëlle; Li, John; Padeganeh, Abbas; Guiral, Sébastien; Duchaine, Jean; Mao, Daniel Y. L.; Bouvier, Michel; Sicheri, Frank; Therrien, Marc

    2016-01-01

    RAF kinases play a prominent role in cancer. Their mode of activation is complex, but critically requires dimerization of their kinase domains. Unexpectedly, several ATP-competitive RAF inhibitors were recently found to promote dimerization and transactivation of RAF kinases in a RAS-dependent manner and as a result undesirably stimulate RAS/ERK-mediated cell growth. The mechanism by which these inhibitors induce RAF kinase domain dimerization remains unclear. Here we describe BRET-based biosensors for the extended RAF family enabling the detection of RAF dimerization in living cells. Notably, we demonstrate the utility of these tools for profiling kinase inhibitors that selectively modulate RAF dimerization as well as for probing structural determinants of RAF dimerization in vivo. Our findings, which appear generalizable to other kinase families allosterically regulated by kinase domain dimerization, suggest a model whereby ATP-competitive inhibitors mediate RAF dimerization by stabilizing a rigid closed conformation of the kinase domain. PMID:23685672

  16. Phthalate esters as peroxisome proliferator carcinogens.

    PubMed Central

    Warren, J R; Lalwani, N D; Reddy, J K

    1982-01-01

    The phthalate ester di(2-ethylhexyl) phthalate is both a peroxisome proliferator and a hepatic carcinogen. Peroxisome proliferators as a class are hepatocarcinogenic in rodent species. However, none of the peroxisome proliferators tested to date including the phthalate esters and related alcohol and acid analogs have demonstrated mutagenic or DNA-damaging activity in the in vitro Salmonella typhimurium/microsomal or the lymphocyte 3H-thymidine assays. A working hypothesis is proposed that peroxisome proliferation itself initiates neoplastic transformation of hepatic parenchymal cells by increasing intracellular rates of DNA-damaging reactive oxygen production. Evidence which supports such a hypothesis includes increased fatty acid beta-oxidation, elevated H2O2 levels, accumulation of peroxidized lipofuscin, disproportionately small increase in catalase, and elevated peroxisomal uricase activity which accompany peroxisome proliferation in hepatocytes. Direct testing of this hypothesis will provide insight into mechanisms of phthalate ester carcinogenicity and cytotoxicity. Images FIGURE 1. PMID:6754363

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

    PubMed

    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

    2015-03-01

    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

  18. COX-2 inhibitors block chemotherapeutic agent-induced apoptosis prior to commitment in hematopoietic cancer cells.

    PubMed

    Cerella, Claudia; Sobolewski, Cyril; Chateauvieux, Sébastien; Henry, Estelle; Schnekenburger, Michael; Ghelfi, Jenny; Dicato, Mario; Diederich, Marc

    2011-11-15

    Enzymatic inhibitors of pro-inflammatory cyclooxygenase-2 (COX-2) possess multiple anti-cancer effects, including chemosensitization. These effects are not always linked to the inhibition of the COX-2 enzyme. Here we analyze the effects of three COX-2 enzyme inhibitors (nimesulide, NS-398 and celecoxib) on apoptosis in different hematopoietic cancer models. Surprisingly, COX-2 inhibitors strongly prevent apoptosis induced by a panel of chemotherapeutic agents. We selected U937 cells as a model of sensitive cells for further studies. Here, we provide evidence that the protective effect is COX-independent. No suppression of the low basal prostaglandin (PG)E(2) production may be observed upon treatment by COX-2 inhibitors. Besides, the non-active celecoxib analog 2,5-dimethyl-celecoxib is able to protect from apoptosis as well. We demonstrate early prevention of the stress-induced apoptotic signaling, prior to Bax/Bak activation. This preventive effect fits with an impairment of the ability of chemotherapeutic agents to trigger apoptogenic stress. Accordingly, etoposide-induced DNA damage is strongly attenuated in the presence of COX-2 inhibitors. In contrast, COX-2 inhibitors do not exert any anti-apoptotic activity when cells are challenged with physiological stimuli (anti-Fas, TNFα or Trail) or with hydrogen peroxide, which do not require internalization and/or are not targeted by chemoresistance proteins. Altogether, our findings show a differential off-target anti-apoptotic effect of COX-2 inhibitors on intrinsic vs. extrinsic apoptosis at the very early steps of intracellular signaling, prior to commitment. The results imply that an exacerbation of the chemoresistance phenomena may be implicated. PMID:21745461

  19. Attenuation by phosphodiesterase inhibitors of lipopolysaccharide-induced thromboxane release and bronchoconstriction in rat lungs.

    PubMed

    Uhlig, S; Featherstone, R L; Held, H D; Nüsing, R; Schudt, C; Wendel, A

    1997-12-01

    Exposure of perfused rat lungs to lipopolysaccharides (LPS) causes induction of cyclooxygenase-2 followed by thromboxane (TX)-mediated bronchoconstriction (BC). Recently, phosphodiesterase (PDE) inhibitors have received much interest because they not only are bronchodilators but also can suppress release of proinflammatory mediators. In the present study, we investigated the effect of three different PDE inhibitors on TX release and BC in LPS-exposed perfused rat lungs. The PDE inhibitors used were motapizone (PDE III specific), rolipram (PDE IV specific), and zardaverine (mixed PDE III and IV specific). At 5 microM, a concentration at which all three compounds selectively block their respective PDE isoenzyme, rolipram (IC50 = 0.04 microM) and zardaverine (IC50 = 1.8 microM) largely attenuated the LPS-induced BC, whereas motapizone was almost ineffective (IC50 = 40 microM). In contrast to LPS, BC induced by the TX-mimetic U46619 was prevented with comparable strength by motapizone and rolipram. In LPS-treated lungs, the TX release was reduced to 50% of controls by rolipram and zardaverine but was unaltered in the presence of 5 microM motapizone. Increasing intracellular cAMP through perfusion of db-cAMP or forskolin (activates adenylate cyclase) also reduced TX release and BC. We conclude that PDE inhibitors act via elevation of intracellular cAMP. Although both PDE III and PDE IV inhibitors can relax airway smooth muscle, in the model of LPS-induced BC, PDE IV inhibitors are more effective because (in contrast to PDE III inhibitors) they also attenuate TX release. PMID:9400021

  20. 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

  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 µM 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. 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. PMID:26616035

  3. Presence of thiamine pyrophosphate in mammalian peroxisomes

    PubMed Central

    Fraccascia, Patrizia; Sniekers, Mieke; Casteels, Minne; Van Veldhoven, Paul P

    2007-01-01

    Background Thiamine pyrophosphate (TPP) is a cofactor for 2-hydroxyacyl-CoA lyase 1 (HACL1), a peroxisomal enzyme essential for the α-oxidation of phytanic acid and 2-hydroxy straight chain fatty acids. So far, HACL1 is the only known peroxisomal TPP-dependent enzyme in mammals. Little is known about the transport of metabolites and cofactors across the peroxisomal membrane and no peroxisomal thiamine or TPP carrier has been identified in mammals yet. This study was undertaken to get a better insight into these issues and to shed light on the role of TPP in peroxisomal metabolism. Results Because of the crucial role of the cofactor TPP, we reanalyzed its subcellular localization in rat liver. In addition to the known mitochondrial and cytosolic pools, we demonstrated, for the first time, that peroxisomes contain TPP (177 ± 2 pmol/mg protein). Subsequently, we verified whether TPP could be synthesized from its precursor thiamine, in situ, by a peroxisomal thiamine pyrophosphokinase (TPK). However, TPK activity was exclusively recovered in the cytosol. Conclusion Our results clearly indicate that mammalian peroxisomes do contain TPP but that no pyrophosphorylation of thiamine occurs in these organelles, implying that thiamine must enter the peroxisome already pyrophosphorylated. Consequently, TPP entry may depend on a specific transport system or, in a bound form, on HACL1 translocation. PMID:17596263

  4. 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

  5. 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

  6. 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...

  7. 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 ...

  8. 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

  9. Ciprofloxacin-Induced Antibacterial Activity Is Attenuated by Phosphodiesterase Inhibitors

    PubMed Central

    Masadeh, Majed M.; Alzoubi, Karem H.; Khabour, Omar F.; Al-Azzam, Sayer I.

    2014-01-01

    Background Ciprofloxacin is a commonly used antibiotic for urinary tract infection that interacts with bacterial topoisomerases leading to oxidative radicals generation and bacterial cell death. Phosphodiesterase inhibitors (PDEis), on the other hand, are commonly used drugs for the management of erectile dysfunction. The group includes agents such as sildenafil, vardenafil, and tadalafil. Objectives We investigated whether PDEi could interfere with the antibacterial activity of ciprofloxacin. Methods PDEis were tested in several reference bacteria, including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis, Acinetobacter baumannii, Proteus mirabilis, and Klebsiella pneumoniae utilizing a standard disc diffusion method and measuring both zones of inhibition and MIC. Results Results from both assays indicated that ciprofloxacin demonstrates potent activity against the tested reference bacteria. Additionally, when bacteria were treated with a combination of ciprofloxacin and sildenafil, tadalafil, or vardenafil, the zones of the combination inhibition were significantly reduced, whereas the MIC values were significantly greater than those of ciprofloxacin alone for all tested bacterial strains. In an attempt to examine the mechanism by which PDEis interfere with the action of ciprofloxacin, we utilized the in vitro E coli DNA gyrase cleavage assay. The results showed that PDEi drugs had no effect on ciprofloxacin’s inhibition of E coli gyrase activity. Conclusions Pretreatment of various reference bacterial cells with PDEis largely inhibited the antibacterial activity of ciprofloxacin. PMID:26649077

  10. Dual targeting of yeast catalase A to peroxisomes and mitochondria.

    PubMed

    Petrova, Ventsislava Y; Drescher, Diane; Kujumdzieva, Anna V; Schmitt, Manfred J

    2004-06-01

    Yeast catalase A (Cta1p) contains two peroxisomal targeting signals (SSNSKF) localized at its C-terminus and within the N-terminal third of the protein, which both can target foreign proteins to peroxisomes. In the present study we demonstrated that Cta1p can also enter mitochondria, although the enzyme lacks a classical mitochondrial import sequence. Cta1p co-targeting was studied in a catalase A null mutant after growth on different carbon sources, and expression of a Cta1p-GFP (green fluorescent protein)-fusion protein or a Cta1p derivative containing either a c-Myc epitope (Cta1p(myc)) or a SKF-extended tag (Cta1p(myc-SKF)). Peroxisomal and mitochondrial co-import of catalase A were tested qualitatively by fluorescence microscopy and functional complementation of a Delta cta1 null mutation, and quantitatively by subcellular fractionation followed by Western blot analysis and enzyme activity assays. Efficient Cta1p import into peroxisomes was observed when cells were cultivated under peroxisome-inducing conditions (i.e. growth on oleate), whereas significant co-import of Cta1p-GFP into mitochondria occurred when cells were grown under respiratory conditions that favour oxygen stress and ROS (reactive oxygen species) accumulation within this organelle. In particular, when cells were grown on the non-fermentable carbon source raffinose, respiration is maximally enhanced, and catalase A was efficiently targeted to the mitochondrial matrix where it presumably functions as scavenger of H2O2 and mitochondrial-derived ROS. PMID:14998369

  11. Dual targeting of yeast catalase A to peroxisomes and mitochondria.

    PubMed Central

    Petrova, Ventsislava Y; Drescher, Diane; Kujumdzieva, Anna V; Schmitt, Manfred J

    2004-01-01

    Yeast catalase A (Cta1p) contains two peroxisomal targeting signals (SSNSKF) localized at its C-terminus and within the N-terminal third of the protein, which both can target foreign proteins to peroxisomes. In the present study we demonstrated that Cta1p can also enter mitochondria, although the enzyme lacks a classical mitochondrial import sequence. Cta1p co-targeting was studied in a catalase A null mutant after growth on different carbon sources, and expression of a Cta1p-GFP (green fluorescent protein)-fusion protein or a Cta1p derivative containing either a c-Myc epitope (Cta1p(myc)) or a SKF-extended tag (Cta1p(myc-SKF)). Peroxisomal and mitochondrial co-import of catalase A were tested qualitatively by fluorescence microscopy and functional complementation of a Delta cta1 null mutation, and quantitatively by subcellular fractionation followed by Western blot analysis and enzyme activity assays. Efficient Cta1p import into peroxisomes was observed when cells were cultivated under peroxisome-inducing conditions (i.e. growth on oleate), whereas significant co-import of Cta1p-GFP into mitochondria occurred when cells were grown under respiratory conditions that favour oxygen stress and ROS (reactive oxygen species) accumulation within this organelle. In particular, when cells were grown on the non-fermentable carbon source raffinose, respiration is maximally enhanced, and catalase A was efficiently targeted to the mitochondrial matrix where it presumably functions as scavenger of H2O2 and mitochondrial-derived ROS. PMID:14998369

  12. Degradation of topoisomerase I induced by topoisomerase I inhibitors is dependent on inhibitor structure but independent of cell death.

    PubMed

    Fu, Q; Kim, S W; Chen, H X; Grill, S; Cheng, Y C

    1999-04-01

    DNA topoisomerase I (top I) is the target of the antitumor drug camptothecin (CPT) and its analogs. CPT induces dose- and time-dependent degradation of top I. Degradation of top I also occurs in a CPT-resistant cell line and, therefore, is not a consequence of cell death. Top I degradation is preceded by the appearance of a high molecular weight ladder of top I immunoreactivity and can be blocked by specific inhibitors of the proteasome. We compared the effects of five top I poisons [CPT, topotecan, 6-N-formylamino-12,13-dihydro-1, 11-dihydroxy-13-(beta-D-glucopyranosyl)-5H-indolo[2,3-a]pyrrolo[3, 4-c]carbazole-5,7(6H)-dione (NB506), camptothecin-(para)-4beta-amino-4'-O-demethyl Epipodophyllotoxin (W1), and camptothecin-(ortho)-4beta-amino-4'-O-demethyl Epipodophyllotoxin (W2)] on cleavable complex formation and top I degradation. Although all five drugs induced cleavable complex formation, two of the drugs, NB506 and W1 did not induce top I degradation. PMID:10101025

  13. 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

  14. In vivo pharmacological evaluation of two novel type II (inducible) nitric oxide synthase inhibitors.

    PubMed

    Tracey, W R; Nakane, M; Basha, F; Carter, G

    1995-05-01

    Selective type II (inducible) nitric oxide synthase (NOS) inhibitors have several potential therapeutic applications, including treatment of sepsis, diabetes, and autoimmune diseases. The ability of two novel, selective inhibitors of type II NOS, S-ethylisothiourea (EIT) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), to inhibit type II NOS function in vivo was studied in lipopolysaccharide (LPS) treated rats. Type II NOS activity was assessed by measuring changes in plasma nitrite and nitrate concentrations ([NOx]). Both EIT and AMT elicited a dose-dependent and > 95% inhibition of the LPS-induced increase in plasma [NOx]. The ED50 values for EIT and AMT were 0.4 and 0.2 mg/kg, respectively. In addition, the administration of LPS and either NOS inhibitor resulted in a dose-dependent increase in animal mortality; neither compound was lethal when administered alone. Pretreatment with L-arginine (but not D-arginine) prevented the mortality, while not affecting the type II NOS-dependent NO production, suggesting the toxicity may be due to inhibition of one of the other NOS isoforms (endothelial or neuronal). Thus, although EIT and AMT are potent inhibitors of type II NOS function in vivo, type II NOS inhibitors of even greater selectivity may need to be developed for therapeutic applications. PMID:7585335

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

    PubMed Central

    Westman, Johan O.; Manikondu, Ramesh Babu; Franzén, 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

  16. 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

  17. 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.

  18. An experimental study on amelioration of dyslipidemia-induced atherosclesis by Clematichinenoside through regulating Peroxisome proliferator-activated receptor-α mediated apolipoprotein A-I, A-II and C-III.

    PubMed

    Liu, Chao; Guo, Qianqian; Lu, Mengchen; Li, Yunman

    2015-08-15

    Prevention or amelioration the prevalence of atherosclerosis has been an effective strategy in the management of cardiovascular diseases. The aim of the study was to scrutinize the effect of Clematichinenoside (AR) on dyslipidemia-induced atherosclerosis and explore its capability on expression of Peroxisome proliferator-activated receptor-α (PPAR-alpha), apolipoprotein A-I (APOA1) and A-II (APOA2), and suppression of apolipoprotein C-III (APOC3) genes and proteins. In the present study, we investigated atherosclerosis effect of AR using a combination of high-fat diet and balloon injury model in rabbits. The levels of biochemical indicators were evaluated in plasma, liver and HepG2 cells using immunoassay technology. In order to expose the underlying mechanism, we evaluated the regulation of PPAR-alpha, APOA1, APOA2 and APOC3 expressions by AR, and we further evaluated the interactions between them after transfection with shRNA (shPPAR-alpha) and, the action of PPAR-alpha in HepG2 cells. We could find that AR markedly promoted the PPAR-alpha transfer from cytoplasm to nucleus which resulted in the alteration of APOA1, APOA2 and APOC3 expressions in HepG2 cells. Moreover, AR significantly reduced total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) levels, and elevated high-density lipoprotein cholesterol (HDL-C) level, which play an important role in dyslipidemia-induced atherosclerosis. In conclusion, AR ameliorated atherosclerosis via the regulation of hepatic lipid metabolism, and AR also contributed to the activation of PPAR-alpha, APOA1, APOA2 and APOC3. Therefore, AR could be a potential therapeutic agent in the treatment of atherosclerosis. PMID:25979856

  19. IKK inhibitor suppresses epithelial-mesenchymal transition and induces cell death in prostate cancer.

    PubMed

    Ping, Hao; Yang, Feiya; Wang, Mingshuai; Niu, Yinong; Xing, Nianzeng

    2016-09-01

    IκB kinase (IKK)/nuclear factor κB (NF-κB) pathway activation is a key event in the acquisition of invasive and metastatic capacities in prostate cancer. A potent small-molecule compound, BMS-345541, was identified as a highly selective IKKα and IKKβ inhibitor to inhibit kinase activity. This study explored the effect of IKK inhibitor on epithelial-mesenchymal transition (EMT), apoptosis and metastasis in prostate cancer. Here, we demonstrate the role of IKK inhibitor reducing proliferation and inducing apoptosis in PC-3 cells. Furthermore, BMS345541 inhibited IκBα phosphorylation and nuclear level of NF-κB/p65 in PC-3 cells. We also observed downregulation of the N-cadherin, Snail, Slug and Twist protein in a dose-dependent manner. BMS‑345541 induced upregulation of the epithelial marker E-cadherin and phosphorylated NDRG1 at protein level. Moreover, BMS‑345541 reduced invasion and metastasis of PC-3 cells in vitro. In conclusion, IKK has a key role in both EMT and apoptosis of prostate cancer. IKK inhibitor can reverse EMT and induce cell death in PCa cells. IKK was identified as a potential target structure for future therapeutic intervention in PCa. PMID:27432067

  20. Exercise-induced ventricular arrhythmias in congestive heart failure and role of ACE inhibitors.

    PubMed

    Hasija, P K; Karloopia, S D; Shahi, B N; Chauhan, S S

    1998-02-01

    Ventricular arrhythmias are considered to be related to left ventricular (LV) dysfunction. ACE inhibitors though improve LV function their beneficial role on exercise-induced ventricular arrhythmias is not established. To study the effects of ACE inhibitors on exercise capacity vis-a-vis their role on exercise-induced ventricular arrhythmias, 25 patients of congestive heart failure (CHF) of various etiologies in NYHA Class II and III were subjected to a prospective randomised controlled trial. The control group comprising of 12 patients received conventional treatment (digitalis and diuretics) and the test group was given enalapril/captopril in addition as tolerated. They were followed up for 3 months. Exercise testing on treadmill and monitoring of clinical and biochemical parameters were done at the beginning and end of study in all cases. Ventricular arrhythmias observed during exercise and post-exercise for 10 minutes was analysed using Lown's grading for frequency and severity of ventricular arrhythmia. The mean exercise duration showed significant improvement on ACE inhibitor as compared to the control group (p < 0.05) however there was no significant change in the grades of arrhythmia. Serum electrolytes and other bio-chemical parameter were within normal range. It is concluded that effect of ACE inhibitor on improving functional capacity in CHF is independent of it's any effect on exercise-induced ventricular arrhythmias. PMID:11273109

  1. Inp1p is a peroxisomal membrane protein required for peroxisome inheritance in Saccharomyces cerevisiae

    PubMed Central

    Fagarasanu, Monica; Fagarasanu, Andrei; Tam, Yuen Yi C.; Aitchison, John D.; Rachubinski, Richard A.

    2005-01-01

    Cells have evolved molecular mechanisms for the efficient transmission of organelles during cell division. Little is known about how peroxisomes are inherited. Inp1p is a peripheral membrane protein of peroxisomes of Saccharomyces cerevisiae that affects both the morphology of peroxisomes and their partitioning during cell division. In vivo 4-dimensional video microscopy showed an inability of mother cells to retain a subset of peroxisomes in dividing cells lacking the INP1 gene, whereas cells overexpressing INP1 exhibited immobilized peroxisomes that failed to be partitioned to the bud. Overproduced Inp1p localized to both peroxisomes and the cell cortex, supporting an interaction of Inp1p with specific structures lining the cell periphery. The levels of Inp1p vary with the cell cycle. Inp1p binds Pex25p, Pex30p, and Vps1p, which have been implicated in controlling peroxisome division. Our findings are consistent with Inp1p acting as a factor that retains peroxisomes in cells and controls peroxisome division. Inp1p is the first peroxisomal protein directly implicated in peroxisome inheritance. PMID:15928207

  2. 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

  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 (PKCβ) activity; however, PKCβ 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. Peroxisomes in brain development and function☆

    PubMed Central

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

    2016-01-01

    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

  5. Proliferation and fission of peroxisomes - An update.

    PubMed

    Schrader, Michael; Costello, Joseph L; Godinho, Luis F; Azadi, Afsoon S; Islinger, Markus

    2016-05-01

    In mammals, peroxisomes perform crucial functions in cellular metabolism, signalling and viral defense which are essential to the health and viability of the organism. In order to achieve this functional versatility peroxisomes dynamically respond to molecular cues triggered by changes in the cellular environment. Such changes elicit a corresponding response in peroxisomes, which manifests itself as a change in peroxisome number, altered enzyme levels and adaptations to the peroxisomal structure. In mammals the generation of new peroxisomes is a complex process which has clear analogies to mitochondria, with both sharing the same division machinery and undergoing a similar division process. How the regulation of this division process is integrated into the cell's response to different stimuli, the signalling pathways and factors involved, remains somewhat unclear. Here, we discuss the mechanism of peroxisomal fission, the contributions of the various division factors and examine the potential impact of post-translational modifications, such as phosphorylation, on the proliferation process. We also summarize the signalling process and highlight the most recent data linking signalling pathways with peroxisome proliferation. PMID:26409486

  6. Natural antioxidants as inhibitors of oxygen species induced mutagenicity.

    PubMed

    Minnunni, M; Wolleb, U; Mueller, O; Pfeifer, A; Aeschbacher, H U

    1992-10-01

    A ternary antioxidant vitamin mix consisting of ascorbic acid, alpha-tocopherol and lecithin as well as a rosemary extract with carnosic acid and carnosol as the two major active ingredients were shown to exhibit strong antimutagenic effects in Ames tester strain TA102. This strain has been shown to be highly sensitive to reactive oxygen species. Mutagenicity was induced by the generation of oxygen radicals by tert-butyl-hydroperoxide (tBOOH) or hydrogen peroxide (H2O2); therefore, the antimutagenic property of the above substances was attributed to their antioxidant properties. In the case of the vitamin mix, ascorbic acid was held responsible for this inhibitory property, whereas for the rosemary extract carnosic acid was identified as the antimutagenic agent. Since oxygen radicals are known to be involved in the multiprocess of carcinogenicity, it is concluded that these antioxidants might exhibit anticarcinogenic properties. PMID:1383702

  7. Treatment with Dimethyl Fumarate attenuates calcineurin inhibitor-induced Nephrotoxicity

    PubMed Central

    Takasu, Chie; Vaziri, Nosratola D.; Li, Shiri; Robles, Lourdes; Vo, Kelly; Takasu, Mizuki; Pham, Christine; Liu, Shuman; Farzaneh, Seyed H.; Foster, Clarence E; Stamos, Michael J; Ichii, Hirohito

    2014-01-01

    Background Cyclosporine A (CsA) is an immunosuppressive drug which has been widely used to prevent rejection following organ transplantation. However, its therapeutic use is limited by nephrotoxicity, in part mediated by oxidative stress. The present study aims to investigate the protective effects of Dimethyl Fumarate (DMF) on CsA-induced nephrotoxicity by enhancing the antioxidant defense system. Methods Male Sprague-Dawley rats were treated with CsA (n=8, 20 mg/kg/day i.p.) orCsA + DMF (n=7, 50 mg/kg/day p.o.) for 28 days. Renal function, histopathology, malondialdehyde (MDA), myeloperoxidase (MPO) levels and anti-oxidant enzyme expression were determined. Results DMF co-treatment ameliorated CsA-induced renal dysfunction as evidenced by significant decrease in serum creatinine (CsA 0.79 ± 0.02 mg/dl vs. CsA + DMF 0.62 ± 0.04 mg/dl, P=0.001) and urea (CsA 66.9 ± 0.4 mg/dl vs. CsA + DMF 53.3 ± 2.6 mg/dl, P<0.0001) levels, as well as improvement of creatinine clearance. DMF also significantly decreased serum MDA and renal tissue MDA and MPO contents. The protein expression of NQO-1, a major cellular anti-oxidant and detoxifying enzyme was significantly enhanced by DMF administration in kidney. Conclusions Administration of DMF has a protective potential against CsA nephrotoxicity. The protection afforded by DMF is mediated in part through inhibiting oxidative stress and inflammation and enhancing the antioxidant capacity. PMID:25710612

  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. Structural basis for induced-fit binding of Rho-kinase to the inhibitor Y-27632.

    PubMed

    Yamaguchi, Hiroto; Miwa, Yukiko; Kasa, Miyuki; Kitano, Ken; Amano, Mutsuki; Kaibuchi, Kozo; Hakoshima, Toshio

    2006-09-01

    Rho-kinase is a main player in the regulation of cytoskeletal events and a promising drug target in the treatment of both vascular and neurological disorders. Here we report the crystal structure of the Rho-kinase catalytic domain in complex with the specific inhibitor Y-27632. Comparison with the structure of PKA bound to this inhibitor revealed a potential induced-fit binding mode that can be accommodated by the phosphate binding loop. This binding mode resembles to that observed in the Rho-kinase-fasudil complex. A structural database search indicated that a pocket underneath the phosphate-binding loop is present that favors binding to a small aromatic ring. Introduction of such a ring group might spawn a new modification scheme of pre-existing protein kinase inhibitors for improved binding capability. PMID:16891330

  11. A novel role for the apoptosis inhibitor ARC in suppressing TNFα-induced regulated necrosis.

    PubMed

    Kung, G; Dai, P; Deng, L; Kitsis, R N

    2014-04-01

    TNFα signaling can promote apoptosis or a regulated form of necrosis. ARC (apoptosis repressor with CARD (caspase recruitment domain)) is an endogenous inhibitor of apoptosis that antagonizes both the extrinsic (death receptor) and intrinsic (mitochondrial/ER) apoptosis pathways. We discovered that ARC blocks not only apoptosis but also necrosis. TNFα-induced necrosis was abrogated by overexpression of wild-type ARC but not by a CARD mutant that is also defective for inhibition of apoptosis. Conversely, knockdown of ARC exacerbated TNFα-induced necrosis, an effect that was rescued by reconstitution with wild-type, but not CARD-defective, ARC. Similarly, depletion of ARC in vivo exacerbated necrosis caused by infection with vaccinia virus, which elicits severe tissue damage through this pathway, and sensitized mice to TNFα-induced systemic inflammatory response syndrome. The mechanism underlying these effects is an interaction of ARC with TNF receptor 1 that interferes with recruitment of RIP1, a critical mediator of TNFα-induced regulated necrosis. These findings extend the role of ARC from an apoptosis inhibitor to a regulator of the TNFα pathway and an inhibitor of TNFα-mediated regulated necrosis. PMID:24440909

  12. 8-Hydroxyeicosapentaenoic Acid Decreases Plasma and Hepatic Triglycerides via Activation of Peroxisome Proliferator-Activated Receptor Alpha in High-Fat Diet-Induced Obese Mice

    PubMed Central

    Yamada, Hidetoshi; Kikuchi, Sayaka; Hakozaki, Mayuka; Motodate, Kaori; Nagahora, Nozomi; Hirose, Masamichi

    2016-01-01

    PPARs regulate the expression of genes involved in lipid homeostasis. PPARs serve as molecular sensors of fatty acids, and their activation can act against obesity and metabolic syndromes. 8-Hydroxyeicosapentaenoic acid (8-HEPE) acts as a PPAR ligand and has higher activity than EPA. However, to date, the PPAR ligand activity of 8-HEPE has only been demonstrated in vitro. Here, we investigated its ligand activity in vivo by examining the effect of 8-HEPE treatment on high fat diet-induced obesity in mice. After the 4-week treatment period, the levels of plasma and hepatic triglycerides in the 8-HEPE-fed mice were significantly lower than those in the HFD-fed mice. The expression of genes regulated by PPARα was significantly increased in 8-HEPE-fed mice compared to those that received only HFD. Additionally, the level of hepatic palmitic acid in 8-HEPE-fed mice was significantly lower than in HFD-fed mice. These results suggested that intake of 8-HEPE induced PPARα activation and increased catabolism of lipids in the liver. We found no significant differences between EPA-fed mice and HFD-fed mice. We demonstrated that 8-HEPE has a larger positive effect on metabolic syndrome than EPA and that 8-HEPE acts by inducing PPARα activation in the liver. PMID:27239345

  13. Retinal toxicity induced by small-molecule Hsp90 inhibitors in beagle dogs.

    PubMed

    Kanamaru, Chisako; Yamada, Yuichiro; Hayashi, Shuji; Matsushita, Tomochika; Suda, Atsushi; Nagayasu, Miho; Kimura, Kazuya; Chiba, Shuichi

    2014-02-01

    Heat shock protein 90 (Hsp90) is a constitutively expressed molecular chaperone and plays an important role in the folding of client proteins with key regulatory roles in growth, survival, differentiation and metastasis. Because inhibition of Hsp90 degrades multiple oncogenic client proteins, it is considered to be an attractive anticancer therapy, and clinical trials of several Hsp90 inhibitors have been carried out. In the present study, two structurally distinct Hsp90 inhibitors, CH5164840 and CH5449302, were orally administered to beagle dogs to evaluate systemic toxicity. CH5164840 induced symptoms that suggest visual disorder, and ophthalmological observation and electroretinography (ERG) revealed loss of pupillary light reflex and abnormal waveforms, respectively. Histopathological examination showed changes in the photoreceptor cell layer and the outer nuclear layer of retina. On the other hand, while there were no clinical symptoms related to visual disorder, animals treated with CH5449302 showed similar abnormalities of ERG responses and histopathological changes in the photoreceptor cell layer and the outer nuclear layer of retina. The visual symptoms and abnormalities of ERG responses were noted at an earlier stage or lower dose than other toxicities in both compounds. Considering that two structurally distinct Hsp90 inhibitors induced a retinal toxicity in dogs after repeated administration, and that visual disorders were also reported in some clinical trials of Hsp90 inhibitors, it would seem highly likely that Hsp90 inhibition induces retinal toxicity. Also, our study indicated that a detailed ocular examination to evaluate the safety of Hsp90 inhibitors would be useful in both preclinical and clinical studies. PMID:24418710

  14. AMP-activated protein kinase is required for exercise-induced peroxisome proliferator-activated receptor γ co-activator 1α translocation to subsarcolemmal mitochondria in skeletal muscle

    PubMed Central

    Smith, Brennan K; Mukai, Kazutaka; Lally, James S; Maher, Amy C; Gurd, Brendon J; Heigenhauser, George J F; Spriet, Lawrence L; Holloway, Graham P

    2013-01-01

    In skeletal muscle, mitochondria exist as two subcellular populations known as subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria. SS mitochondria preferentially respond to exercise training, suggesting divergent transcriptional control of the mitochondrial genomes. The transcriptional co-activator peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and mitochondrial transcription factor A (Tfam) have been implicated in the direct regulation of the mitochondrial genome in mice, although SS and IMF differences may exist, and the potential signalling events regulating the mitochondrial content of these proteins have not been elucidated. Therefore, we examined the potential for PGC-1α and Tfam to translocate to SS and IMF mitochondria in human subjects, and performed experiments in rodents to identify signalling mechanisms regulating these translocation events. Acute exercise in humans and rats increased PGC-1α content in SS but not IMF mitochondria. Acute exposure to 5-aminoimidazole-4-carboxamide-1-β-ribofuranoside in rats recapitulated the exercise effect of increased PGC-1α protein within SS mitochondria only, suggesting that AMP-activated protein kinase (AMPK) signalling is involved. In addition, rendering AMPK inactive (AMPK kinase dead mice) prevented exercise-induced PGC-1α translocation to SS mitochondria, further suggesting that AMPK plays an integral role in these translocation events. In contrast to the conserved PGC-1α translocation to SS mitochondria across species (humans, rats and mice), acute exercise only increased mitochondrial Tfam in rats. Nevertheless, in rat resting muscle PGC-1α and Tfam co-immunoprecipate with α-tubulin, suggesting a common cytosolic localization. These data suggest that exercise causes translocation of PGC-1α preferentially to SS mitochondria in an AMPK-dependent manner. PMID:23297307

  15. The peroxisome proliferator-activated receptor α agonist, AZD4619, induces alanine aminotransferase-1 gene and protein expression in human, but not in rat hepatocytes: Correlation with serum ALT levels.

    PubMed

    Thulin, Petra; Bamberg, Krister; Buler, Marcin; Dahl, Björn; Glinghammar, Björn

    2016-09-01

    Alanine aminotransferase (ALT) in serum is the standard biomarker for liver injury. We have previously described a clinical trial with a novel selective peroxisome proliferator-activated receptor α (PPARα) agonist (AZD4619), which unexpectedly caused increased serum levels of ALT in treated individuals without any other evidence of liver injury. We pinpointed a plausible mechanism through which AZD4619 could increase serum ALT levels; namely through the PPARα-specific activation of the human ALT1 gene at the transcriptional level. In the present study, we present data from the preceding rat toxicity study, demonstrating that AZD4619 had no effect on rat serum ALT activity levels, and further experiments were performed to elucidate the mechanisms responsible for this species-related difference. Our results revealed that AZD4619 increased ALT1 protein expression in a dose-dependent manner in human, but not in rat primary hepatocytes. Cloning of the human and rat ALT1 promoters into luciferase vectors confirmed that AZD4619 induced only the human, but not the rat ALT1 gene promoter in a dose-dependent manner. In PPARα-GAL4 reporter gene assays, AZD4619 was >100-fold more potent on the human vs. rat PPARα levels, explaining the differences in induction of the ALT1 gene between the species at the concentration range tested. These data demonstrate the usefulness of the human and rat ALT1 reporter gene assays for testing future drug candidates at the preclinical stage. In drug discovery projects, these assays elucidate whether elevations in ALT levels observed in vivo or in the clinic are due to metabolic effects rather than a toxic event in the liver. PMID:27430334

  16. 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

  17. 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

  18. 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 α-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

  19. Effects of the inducible nitric oxide synthase inhibitor aminoguanidine in two different rat models of schizophrenia.

    PubMed

    Lafioniatis, Anastasios; Orfanidou, Martha A; Papadopoulou, Evangelia S; Pitsikas, Nikolaos

    2016-08-01

    Several lines evidence indicate that the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist ketamine and the mixed dopamine (DA) D1/D2 receptor agonist apomorphine induce schizophrenia-like symptoms in rodents, including memory impairments and social withdrawal. Nitric oxide (NO) has been proposed to act as an intracellular messenger in the brain and its overproduction is associated with schizophrenia. The current study was designed to investigate the ability of the inducible NO synthase (iNOS) inhibitor aminoguanidine (AG) to counteract schizophrenia-like behavioural deficits produced by ketamine and apomorphine in rats. The efficacy of AG to antagonize extinction of recognition memory, ketamine and apomorphine-induced recognition memory impairments was tested utilizing the novel object recognition task (NORT). Further, the efficacy of AG to attenuate ketamine-induced social withdrawal was examined in the social interaction test. AG (25 and 50mg/kg) antagonized extinction of recognition memory and reversed ketamine (3mg/kg) and apomorphine (1mg/kg)-induced recognition memory deficits. In contrast, AG (50 and 100mg/kg) did not counteract the ketamine (8mg/kg)-induced social isolation. The present data show that the iNOS inhibitor AG counteracted extinction of recognition memory and reversed recognition memory deficits produced by dysfunction of the glutamatergic and the dopaminergic (DAergic) system in rats. Therefore, AG may be efficacious in attenuating memory impairments often observed in schizophrenia patients. PMID:27132765

  20. Does combined peroxisome proliferator-activated receptors-agonist and pravastatin therapy attenuate the onset of diabetes-induced experimental nephropathy?

    PubMed Central

    Gad, Hayam I.

    2014-01-01

    Objectives: To investigate the combined effects of rosiglitazone and pravastatin on renal functions in early streptozotocin induced diabetic nephropathy (DN). Methods: This study was carried out at King Khalid University Hospital Animal House, Riyadh, Saudi Arabia from August 2013 to February 2014. Fifty male Wistar rats were assigned to normal control rats and diabetic rats that received saline, rosiglitazone, pravastatin, or rosiglitazone+pravastatin for 2 months. Their weight range was 230-250 gm, and age range was from 18-20 weeks. At the end of experiment, creatinine clearance, and urinary albumin to creatinine ratio (ACR) were measured. Blood samples were analyzed for transferrin, glycosylated hemoglobin (HbA1c), lipid profile, tumor necrosis factor-alpha (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and lipid peroxide. Results: Rosiglitazone treatment increased creatinine clearance and plasma transferrin, and decreased urinary ACR, HbA1c, plasma TNF-α, ICAM-1, and serum lipid peroxide levels without affecting the altered lipid profile. Pravastatin treatment produced similar results and normalized the lipid alteration. The combination of rosiglitazone and pravastatin was more effective in attenuating the diabetes-induced nephropathy compared with treatment with either drug alone. Conclusion: The combination strategy of rosiglitazone and pravastatin may provide a potential synergistic renoprotective effect against DN by improving renal functions and reducing indices of DN. PMID:25399210

  1. The Calpain Inhibitor MDL28170 Induces the Expression of Apoptotic Markers in Leishmania amazonensis Promastigotes

    PubMed Central

    Marinho, Fernanda A.; Gonçalves, Keyla C. S.; Oliveira, Simone S. C.; Gonçalves, Diego S.; Matteoli, Filipe P.; Seabra, Sergio H.; Oliveira, Ana Carolina S.; Bellio, Maria; Oliveira, Selma S.; Souto-Padrón, Thaïs; d'Avila-Levy, Claudia M.; Santos, André L. S.; Branquinha, Marta H.

    2014-01-01

    Background Human cutaneous leishmaniasis is caused by distinct species, including Leishmania amazonensis. Treatment of cutaneous leishmaniasis is far from satisfactory due to increases in drug resistance and relapses, and toxicity of compounds to the host. As a consequence for this situation, the development of new leishmanicidal drugs and the search of new targets in the parasite biology are important goals. Methodology/Principal Findings In this study, we investigated the mechanism of death pathway induced by the calpain inhibitor MDL28170 on Leishmania amazonensis promastigote forms. The combined use of different techniques was applied to contemplate this goal. MDL28170 treatment with IC50 (15 µM) and two times the IC50 doses induced loss of parasite viability, as verified by resazurin assay, as well as depolarization of the mitochondrial membrane, which was quantified by JC-1 staining. Scanning and transmission electron microscopic images revealed drastic alterations on the parasite morphology, some of them resembling apoptotic-like death, including cell shrinking, surface membrane blebs and altered chromatin condensation pattern. The lipid rearrangement of the plasma membrane was detected by Annexin-V labeling. The inhibitor also induced a significant increase in the proportion of cells in the sub-G0/G1 phase, as quantified by propidium iodide staining, as well as genomic DNA fragmentation, detected by TUNEL assay. In cells treated with MDL28170 at two times the IC50 dose, it was also possible to observe an oligonucleossomal DNA fragmentation by agarose gel electrophoresis. Conclusions/Significance The data presented in the current study suggest that MDL28170 induces apoptotic marker expression in promastigotes of L. amazonensis. Altogether, the results described in the present work not only provide a rationale for further exploration of the mechanism of action of calpain inhibitors against trypanosomatids, but may also widen the investigation of the

  2. Age-dependent roles of peroxisomes in the hippocampus of a transgenic mouse model of Alzheimer’s disease

    PubMed Central

    2013-01-01

    Background Alzheimer’s Disease (AD) is a progressive neurodegenerative disease, especially affecting the hippocampus. Impairment of cognitive and memory functions is associated with amyloid β-peptide-induced oxidative stress and alterations in lipid metabolism. In this scenario, the dual role of peroxisomes in producing and removing ROS, and their function in fatty acids β-oxidation, may be critical. This work aims to investigating the possible involvement of peroxisomes in AD onset and progression, as studied in a transgenic mouse model, harboring the human Swedish familial AD mutation. We therefore characterized the peroxisomal population in the hippocampus, focusing on early, advanced, and late stages of the disease (3, 6, 9, 12, 18 months of age). Several peroxisome-related markers in transgenic and wild-type hippocampal formation were comparatively studied, by a combined molecular/immunohistochemical/ultrastructural approach. Results Our results demonstrate early and significant peroxisomal modifications in AD mice, compared to wild-type. Indeed, the peroxisomal membrane protein of 70 kDa and acyl-CoA oxidase 1 are induced at 3 months, possibly reflecting the need for efficient fatty acid β-oxidation, as a compensatory response to mitochondrial dysfunction. The concomitant presence of oxidative damage markers and the altered expression of antioxidant enzymes argue for early oxidative stress in AD. During physiological and pathological brain aging, important changes in the expression of peroxisome-related proteins, also correlating with ongoing gliosis, occur in the hippocampus. These age- and genotype-based alterations, strongly dependent on the specific marker considered, indicate metabolic and/or numerical remodeling of peroxisomal population. Conclusions Overall, our data support functional and biogenetic relationships linking peroxisomes to mitochondria and suggest peroxisomal proteins as biomarkers/therapeutic targets in pre-symptomatic AD. PMID

  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. Vascular Endothelial Growth Factor Inhibitor-Induced Hypertension: Basics for Primary Care Providers

    PubMed Central

    Escalante, Carmen P.; Zalpour, Ali

    2011-01-01

    Frequently, primary care providers continue to manage the overall medical care of cancer patients. With newer and often more potent antitumor agents, patients may present to their local physicians with drug-induced toxicities such as hypertension induced by vascular endothelial growth factor (VEGF) inhibitors. It is imperative that these healthcare providers are aware of basic aspects of this drug class, as its use has increased significantly in the last several years. Uncontrolled or malignant hypertension due to these agents should be recognized readily and treated early to prevent more severe outcomes. This overview provides a brief background on the role of VEGF and angiogenesis in tumor metabolism as well as theories of the mechanism of VEGF inhibitors and hypertension. Helpful clinical practice aspects including the types of inhibitors used in the United States and their pharmacologic characteristics will be discussed. Also, diagnosis and treatment of hypertension induced by vascular endothelial growth factors are reviewed. A summary of key aspects of this drug class and hypertension is included. PMID:21629798

  5. Peroxisome is a reservoir of intracellular calcium.

    PubMed

    Raychaudhury, Bikramjit; Gupta, Shreedhara; Banerjee, Shouvik; Datta, Salil C

    2006-07-01

    We have examined fura 2-loaded purified peroxisomes under confocal microscope to prove that this mammalian organelle is a store of intracellular calcium pool. Presence of calcium channel and vanadate sensitive Ca(2+)-ATPase in the purified peroxisomal membrane has been demonstrated. We have further observed that machineries to maintain calcium pool in this mammalian organelle are impaired during infection caused by Leishmania donovani. Results reveal that peroxisomes have a merit to play a significant role in the metabolism of intracellular calcium. PMID:16713100

  6. Transcription inhibitors prevent amnesia induced by NMDA antagonist-mediated impairment of memory reconsolidation.

    PubMed

    Nikitin, Vladimir P; Solntseva, Svetlana V; Shevelkin, Alexey V

    2016-09-01

    Recent studies report that long-term memory retrieval can induce memory reconsolidation, and impairment of this reconsolidation might lead to amnesia. Previously, we found that reconsolidation of a conditioned food aversion memory could be disrupted by translation inhibitors for up to 3 h following a reconsolidation event, thus inducing amnesia. We examined the role of transcription processes in the induction of amnesia in the land snail, Helix lucorum. It received N-methyl-D-aspartate (NMDA) glutamate receptor antagonist and transcription inhibitor 2 days after learning in a neutral context environment; it was then transferred to the learning context followed by reminder with conditioned food stimulus. NMDA receptor blockade, followed by a reminder session, impaired reconsolidation of an aversive memory. Simultaneous administration of an NMDA receptor antagonist and a transcription inhibitor prior to reminder of an aversive event prevented amnesia induction. In contrast, when a transcription inhibitor alone was injected prior to a reminder session, the blockade had no effect on memory. We found that transcription inhibition 0-6 h after amnesia induction suppressed memory loss, but this suppression was lost when inhibitors were administered 9 h after amnesia. Thus, amnesia is likely dependent on transcription processes within a 9-h time window. We can hypothesize that amnesia induction initiates synthesis of specific mRNAs and proteins; furthermore, these events occur within specific time-dependent windows. Our findings could prove useful for the analysis of amnesia formation and for the development of possible ways to prevent memory loss associated with various diseases and injuries in animals and humans. PMID:26742927

  7. Peroxisomal Pex3 Activates Selective Autophagy of Peroxisomes via Interaction with the Pexophagy Receptor Atg30*

    PubMed Central

    Burnett, Sarah F.; Farré, Jean-Claude; Nazarko, Taras Y.; Subramani, Suresh

    2015-01-01

    Pexophagy is a process that selectively degrades peroxisomes by autophagy. The Pichia pastoris pexophagy receptor Atg30 is recruited to peroxisomes under peroxisome proliferation conditions. During pexophagy, Atg30 undergoes phosphorylation, a prerequisite for its interactions with the autophagy scaffold protein Atg11 and the ubiquitin-like protein Atg8. Atg30 is subsequently shuttled to the vacuole along with the targeted peroxisome for degradation. Here, we defined the binding site for Atg30 on the peroxisomal membrane protein Pex3 and uncovered a role for Pex3 in the activation of Atg30 via phosphorylation and in the recruitment of Atg11 to the receptor protein complex. Pex3 is classically a docking protein for other proteins that affect peroxisome biogenesis, division, and segregation. We conclude that Pex3 has a role beyond simple docking of Atg30 and that its interaction with Atg30 regulates pexophagy in the yeast P. pastoris. PMID:25694426

  8. 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.

  9. 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.

  10. 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

  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. Pip2p: a transcriptional regulator of peroxisome proliferation in the yeast Saccharomyces cerevisiae.

    PubMed Central

    Rottensteiner, H; Kal, A J; Filipits, M; Binder, M; Hamilton, B; Tabak, H F; Ruis, H

    1996-01-01

    In Saccharomyces cerevisiae, peroxisomes are the exclusive site for the degradation of fatty acids. Upon growth with the fatty acid oleic acid as sole carbon source, not only are the enzymes of beta-oxidation and catalase A induced, but also the peroxisomal compartment as a whole increases in volume and the number of organelles per cell rises. We previously identified a cis-acting DNA sequence [oleate response element (ORE)] involved in induction of genes encoding peroxisomal proteins. The aim of our investigation was to test whether a single mechanism acting via the ORE coordinates the events necessary for the proliferation of an entire organelle. Here we report the cloning and characterization of the oleate-specific transcriptional activator protein Pip2p (pip: peroxisome induction pathway). Pip2p contains a typical Zn(2)-Cys(6) cluster domain and binds to OREs. A pip2 deletion strain is impaired in growth on oleate as sole carbon source and the induction of beta-oxidation enzymes is abolished. Moreover, only a few, small peroxisomes per cell can be detected. These results indicate that fatty acids activate Pip2p, which in turn activates the transcription of genes encoding beta-oxidation components and acts as the crucial activator of peroxisomes. Images PMID:8670793

  13. PEX11 family members are membrane elongation factors that coordinate peroxisome proliferation and maintenance.

    PubMed

    Koch, Johannes; Pranjic, Kornelija; Huber, Anja; Ellinger, Adolf; Hartig, Andreas; Kragler, Friedrich; Brocard, Cécile

    2010-10-01

    Dynamic changes of membrane structure are intrinsic to organelle morphogenesis and homeostasis. Ectopic expression of proteins of the PEX11 family from yeast, plant or human lead to the formation of juxtaposed elongated peroxisomes (JEPs),which is evocative of an evolutionary conserved function of these proteins in membrane tubulation. Microscopic examinations reveal that JEPs are composed of independent elongated peroxisomes with heterogeneous distribution of matrix proteins. We established the homo- and heterodimerization properties of the human PEX11 proteins and their interaction with the fission factor hFis1, which is known to recruit the GTPase DRP1 to the peroxisomal membrane. We show that excess of hFis1 but not of DRP1 is sufficient to fragment JEPs into normal round-shaped organelles, and illustrate the requirement of microtubules for JEP formation. Our results demonstrate that PEX11-induced JEPs represent intermediates in the process of peroxisome membrane proliferation and that hFis1 is the limiting factor for progression. Hence, we propose a model for a conserved role of PEX11 proteins in peroxisome maintenance through peroxisome polarization, membrane elongation and segregation. PMID:20826455

  14. 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.

  15. 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...

  16. Next-generation proteasome inhibitor MLN9708 sensitizes breast cancer cells to doxorubicin-induced apoptosis

    PubMed Central

    Wang, Hao; Yu, Yang; Jiang, Zheng; Cao, Wen-Ming; Wang, Zhenyu; Dou, Jun; Zhao, Yanling; Cui, Yunfu; Zhang, Hong

    2016-01-01

    Doxorubicin (Dox), one of the most effective chemotherapy drug for cancer treatment, is limited by its severe side effects and chemoresistance. Dox induces DNA damage and leads to significant proteomic changes in the cancer cells, which makes the ubiquitin-proteasome system a potential target to enhance the efficacy of Dox therapy. The unsuccessful clinical trials of proteasome inhibitor PS-341 (bortezomib) in solid tumors led to the invention of MLN9708 (ixazomib), an orally bioavailable next-generation proteasome inhibitor with improved pharmacokinetic and pharmacodynamic features. In this preclinical study, we used eight human breast cancer cell lines, which represent the major molecular subtypes of breast cancer, to validate the cytotoxic effects of MLN9708, alone and in combination with Dox. We found that MLN9708 had cytotoxic effects, induced autophagy and MKP-1 expression, and enhanced Dox-induced apoptosis in these cell lines. MLN9708 also enhanced Dox-induced JNK and p38 phosphorylation and inhibited Dox-induced IκBα degradation. Our in vitro results suggest that MLN9708 has antitumor effects in breast cancer and can sensitize breast cancer cells to Dox treatment. This promising combination may be an effective and feasible therapeutic option for treating breast cancer and warrants clinical validation. PMID:27217076

  17. Histone Deacetylase Inhibitors Facilitate Dihydroartemisinin-Induced Apoptosis in Liver Cancer In Vitro and In Vivo

    PubMed Central

    Zhang, Chris Zhiyi; Pan, Yinghua; Cao, Yun; Lai, Paul B. S.; Liu, Lili; Chen, George Gong; Yun, Jingping

    2012-01-01

    Liver cancer ranks in prevalence and mortality among top five cancers worldwide. Accumulating interests have been focused in developing new strategies for liver cancer treatment. We have previously showed that dihydroartemisinin (DHA) exhibited antitumor activity towards liver cancer. In this study, we demonstrated that histone deacetylase inhibitors (HDACi) significantly augmented the antineoplastic effect of DHA via increasing apoptosis in vitro and in vivo. Inhibition of ERK phosphorylation contributed to DHA-induced apoptosis, due to the fact that inhibitor of ERK phosphorylation (PD98059) increased DHA-induced apoptosis. Compared with DHA alone, the combined treatment with DHA and HDACi reduced mitochondria membrane potential, released cytochrome c into cytoplasm, increased p53 and Bak, decreased Mcl-1 and p-ERK, activated caspase 3 and PARP, and induced apoptotic cells. Furthermore, we showed that HDACi pretreatment facilitated DHA-induced apoptosis. In Hep G2-xenograft carrying nude mice, the intraperitoneal injection of DHA and SAHA resulted in significant inhibition of xenograft tumors. Results of TUNEL and H&E staining showed more apoptosis induced by combined treatment. Immunohistochemistry data revealed the activation of PARP, and the decrease of Ki-67, p-ERK and Mcl-1. Taken together, our data suggest that the combination of HDACi and DHA offers an antitumor effect on liver cancer, and this combination treatment should be considered as a promising strategy for chemotherapy. PMID:22761917

  18. Next-generation proteasome inhibitor MLN9708 sensitizes breast cancer cells to doxorubicin-induced apoptosis.

    PubMed

    Wang, Hao; Yu, Yang; Jiang, Zheng; Cao, Wen-Ming; Wang, Zhenyu; Dou, Jun; Zhao, Yanling; Cui, Yunfu; Zhang, Hong

    2016-01-01

    Doxorubicin (Dox), one of the most effective chemotherapy drug for cancer treatment, is limited by its severe side effects and chemoresistance. Dox induces DNA damage and leads to significant proteomic changes in the cancer cells, which makes the ubiquitin-proteasome system a potential target to enhance the efficacy of Dox therapy. The unsuccessful clinical trials of proteasome inhibitor PS-341 (bortezomib) in solid tumors led to the invention of MLN9708 (ixazomib), an orally bioavailable next-generation proteasome inhibitor with improved pharmacokinetic and pharmacodynamic features. In this preclinical study, we used eight human breast cancer cell lines, which represent the major molecular subtypes of breast cancer, to validate the cytotoxic effects of MLN9708, alone and in combination with Dox. We found that MLN9708 had cytotoxic effects, induced autophagy and MKP-1 expression, and enhanced Dox-induced apoptosis in these cell lines. MLN9708 also enhanced Dox-induced JNK and p38 phosphorylation and inhibited Dox-induced IκBα degradation. Our in vitro results suggest that MLN9708 has antitumor effects in breast cancer and can sensitize breast cancer cells to Dox treatment. This promising combination may be an effective and feasible therapeutic option for treating breast cancer and warrants clinical validation. PMID:27217076

  19. Translation inhibitors induce formation of cholesterol ester-rich lipid droplets.

    PubMed

    Suzuki, Michitaka; Ohsaki, Yuki; Tatematsu, Tsuyako; Shinohara, Yuki; Maeda, Takashi; Cheng, Jinglei; Fujimoto, Toyoshi

    2012-01-01

    Lipid droplets (LDs) in non-adipocytes contain triglycerides (TG) and cholesterol esters (CE) in variable ratios. TG-rich LDs are generated when unsaturated fatty acids are administered, but the conditions that induce CE-rich LD formation are less well characterized. In the present study, we found that protein translation inhibitors such as cycloheximide (CHX) induced generation of CE-rich LDs and that TIP47 (perilipin 3) was recruited to the LDs, although the expression of this protein was reduced drastically. Electron microscopy revealed that LDs formed in CHX-treated cells possess a distinct electron-dense rim that is not found in TG-rich LDs, whose formation is induced by oleic acid. CHX treatment caused upregulation of mTORC1, but the CHX-induced increase in CE-rich LDs occurred even when rapamycin or Torin1 was given along with CHX. Moreover, the increase in CE was seen in both wild-type and autophagy-deficient Atg5-null mouse embryonic fibroblasts, indicating that mTORC1 activation and suppression of autophagy are not necessary to induce the observed phenomenon. The results showed that translation inhibitors cause a significant change in the lipid ester composition of LDs by a mechanism independent of mTORC1 signaling and autophagy. PMID:22879956

  20. Curcumin Attenuates Beta-Amyloid-Induced Neuroinflammation via Activation of Peroxisome Proliferator-Activated Receptor-Gamma Function in a Rat Model of Alzheimer's Disease.

    PubMed

    Liu, Zun-Jing; Li, Zhong-Hao; Liu, Lei; Tang, Wen-Xiong; Wang, Yu; Dong, Ming-Rui; Xiao, Cheng

    2016-01-01

    Neuroinflammation is known to have a pivotal role in the pathogenesis of Alzheimer's disease (AD), and curcumin has been reported to have therapeutical effects on AD because of its anti-inflammatory effects. Curcumin is not only a potent PPARγ agonist, but also has neuroprotective effects on cerebral ischemic injury. However, whether PPARγ activated by curcumin is responsible for the anti-neuroinflammation and neuroprotection on AD remains unclear, and needs to be further investigated. Here, using both APP/PS1 transgenic mice and beta-amyloid-induced neuroinflammation in mixed neuronal/glial cultures, we showed that curcumin significantly alleviated spatial memory deficits in APP/PS1 mice and promoted cholinergic neuronal function in vivo and in vitro. Curcumin also reduced the activation of microglia and astrocytes, as well as cytokine production and inhibited nuclear factor kappa B (NF-κB) signaling pathway, suggesting the beneficial effects of curcumin on AD are attributable to the suppression of neuroinflammation. Attenuation of these beneficial effects occurred when co-administrated with PPARγ antagonist GW9662 or silence of PPARγ gene expression, indicating that PPARγ might be involved in anti-inflammatory effects. Circular dichroism and co-immunoprecipitation analysis showed that curcumin directly bound to PPARγ and increased the transcriptional activity and protein levels of PPARγ. Taking together, these data suggested that PPARγ might be a potential target of curcumin, acting to alleviate neuroinflammation and improve neuronal function in AD. PMID:27594837

  1. Curcumin Attenuates Beta-Amyloid-Induced Neuroinflammation via Activation of Peroxisome Proliferator-Activated Receptor-Gamma Function in a Rat Model of Alzheimer's Disease

    PubMed Central

    Liu, Zun-Jing; Li, Zhong-Hao; Liu, Lei; Tang, Wen-Xiong; Wang, Yu; Dong, Ming-Rui; Xiao, Cheng

    2016-01-01

    Neuroinflammation is known to have a pivotal role in the pathogenesis of Alzheimer's disease (AD), and curcumin has been reported to have therapeutical effects on AD because of its anti-inflammatory effects. Curcumin is not only a potent PPARγ agonist, but also has neuroprotective effects on cerebral ischemic injury. However, whether PPARγ activated by curcumin is responsible for the anti-neuroinflammation and neuroprotection on AD remains unclear, and needs to be further investigated. Here, using both APP/PS1 transgenic mice and beta-amyloid-induced neuroinflammation in mixed neuronal/glial cultures, we showed that curcumin significantly alleviated spatial memory deficits in APP/PS1 mice and promoted cholinergic neuronal function in vivo and in vitro. Curcumin also reduced the activation of microglia and astrocytes, as well as cytokine production and inhibited nuclear factor kappa B (NF-κB) signaling pathway, suggesting the beneficial effects of curcumin on AD are attributable to the suppression of neuroinflammation. Attenuation of these beneficial effects occurred when co-administrated with PPARγ antagonist GW9662 or silence of PPARγ gene expression, indicating that PPARγ might be involved in anti-inflammatory effects. Circular dichroism and co-immunoprecipitation analysis showed that curcumin directly bound to PPARγ and increased the transcriptional activity and protein levels of PPARγ. Taking together, these data suggested that PPARγ might be a potential target of curcumin, acting to alleviate neuroinflammation and improve neuronal function in AD. PMID:27594837

  2. 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

  3. 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

  4. Anti-inflammatory and anti-hyperalgesic effect of all-trans retinoic acid in carrageenan-induced paw edema in Wistar rats: Involvement of peroxisome proliferator-activated receptor-β/δ receptors

    PubMed Central

    Gill, Navneet; Bijjem, Krishna Reddy V.; Sharma, Pyare L.

    2013-01-01

    Objective: In this study, we investigated the role of peroxisome proliferator-activated receptors (PPAR)-β/δ receptors in carrageenan-induced inflammation and in the anti-inflammatory effects of all-trans retinoic acid (ATRA). Materials and Methods: The λ-carrageenan (0.1 ml of 1% w/v) was injected into intra-plantar (i.pl.) region of the hind paw to produce acute inflammation. Paw volume was measured by using the mercury plethysmography. Further, mechanical and thermal hyperalgesia (TH) were assessed by using the dynamic plantar aesthesiometer and plantar test apparatus, respectively. In addition, markers of oxido-nitrosative stress were assessed spectrophotometrically in the hind paw tissue 5 h post-carrageenan. Results: An i.pl injection of carrageenan has produced a marked mechanical hyperalgesia (MH) and TH in ipsilateral paw, which was associated with significant elevated oxido-nitrosative stress. Treatment with ATRA (5 mg/kg/p.o/4 days) and GW0742, a selective PPAR-β/δ receptor agonist (0.1 mg/kg/i.p/4 days), significantly decreased the paw volume, mechanical and TH as compared to vehicle control. Administration of GSK0660, selective PPAR-β/δ receptor antagonist, at a dose of (0.3 mg/kg/i.p/4 days), did not produce a significant effect on carrageenan-induced paw edema, MH and TH. However, co-administration of GSK0660 (0.3 mg/kg/i.p/4 days) along with both ATRA (5 mg/kg/p.o/4 days) and GW0742 (0.1 mg/kg/i.p/4 days), significantly reverse the decreased paw edema, MH, and TH. These observed ameliorative effects on inflammatory pain symptoms are correlated with the extent of reduction of oxido-nitrosative stress. Conclusion: From above findings, it can be concluded that ATRA exerts anti-inflammatory and anti-hyperalgesic effect, possibly through activation of PPAR-β/δ and subsequent reduction of oxido-nitrosative stress. PMID:23833373

  5. Natural furocoumarins as inducers and inhibitors of cytochrome P450 1A1 in rat hepatocytes.

    PubMed

    Baumgart, Annette; Schmidt, Melanie; Schmitz, Hans-Joachim; Schrenk, Dieter

    2005-02-15

    Furocoumarins are natural plant constituents present in medicinal plants and in a variety of foods such as grapefruit juice. They are phototoxic and act as potent inhibitors of drug metabolism. We have investigated the interaction of four furocoumarins angelicin, bergamottin, isopimpinellin, and 8-methoxypsoralen with the expression and activity of aryl hydrocarbon receptor (AhR)-regulated CYP1A1 in rat hepatocytes in primary culture, both in the presence and absence of light. In intact hepatocytes pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin and in microsomes isolated thereof, all furocoumarins tested acted as potent inhibitors of CYP1A1 activity bergamottin being the most potent inhibitor in microsomes with an IC(50) of 10 nM in the presence and 60 nM in the absence of light. 8-Methoxypsoralen and angelicin led to a significant induction of CYP1A1 mRNA in hepatocytes, while all furocoumarins except bergamottin increased xenobiotic-responsive element-driven reporter gene expression in transfected H4IIE rat hepatoma cells when light was excluded. Furthermore, all furocoumarins tested induced the expression of endogenous, immunoreactive CYP1A1 protein, primarily in the dark. In conclusion, our results demonstrate that individual furocoumarins present in food and medicinal plants can interfere with AhR-regulated CYP1A1 expression and activity in at least three major ways, i.e., (i) act as highly potent inhibitors of the catalytic activity of CYP1A1 both in the presence and absence of light, (ii) induce CYP1A1 gene expression in the absence of light via activation of the AhR, and (iii) induce CYP1A1 gene expression without activation of the AhR. PMID:15670584

  6. Giant peroxisomes in a moss (Physcomitrella patens) peroxisomal biogenesis factor 11 mutant.

    PubMed

    Kamisugi, Yasuko; Mitsuya, Shiro; El-Shami, Mahmoud; Knight, Celia D; Cuming, Andrew C; Baker, Alison

    2016-01-01

    Peroxisomal biogenesis factor 11 (PEX11) proteins are found in yeasts, mammals and plants, and play a role in peroxisome morphology and regulation of peroxisome division. The moss Physcomitrella patens has six PEX11 isoforms which fall into two subfamilies, similar to those found in monocots and dicots. We carried out targeted gene disruption of the Phypa_PEX11-1 gene and compared the morphological and cellular phenotypes of the wild-type and mutant strains. The mutant grew more slowly and the development of gametophores was retarded. Mutant chloronemal filaments contained large cellular structures which excluded all other cellular organelles. Expression of fluorescent reporter proteins revealed that the mutant strain had greatly enlarged peroxisomes up to 10 μm in diameter. Expression of a vacuolar membrane marker confirmed that the enlarged structures were not vacuoles, or peroxisomes sequestered within vacuoles as a result of pexophagy. Phypa_PEX11 targeted to peroxisome membranes could rescue the knock out phenotype and interacted with Fission1 on the peroxisome membrane. Moss PEX11 functions in peroxisome division similar to PEX11 in other organisms but the mutant phenotype is more extreme and environmentally determined, making P. patens a powerful system in which to address mechanisms of peroxisome proliferation and division. PMID:26542980

  7. 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

  8. Protection from impulse noise-induced hearing loss with novel Src-protein tyrosine kinase inhibitors

    PubMed Central

    Bielefeld, Eric C.; Hangauer, David; Henderson, Donald

    2011-01-01

    Apoptosis is a significant mechanism of cochlear hair cell loss from noise. Molecules that inhibit apoptotic intracellular signaling reduce cochlear damage and hearing loss from noise. The current study is an extension of a previous study of the protective value of Src-protein tyrosine kinase inhibitors against noise (Harris et al., 2005). The current study tested three Src-inhibitors: the indole-based KX1-141, the biaryl-based KX2-329, and the ATP-competitive KX2-328. Each of the three drugs was delivered into the chinchillas’ cochleae by allowing the solutions to diffuse across the round window membrane thirty minutes prior to exposure to impulse noise. Hearing thresholds were measured using auditory evoked responses from electrodes in the inferior colliculi. Ears treated with KX2-329 showed significantly lower threshold shifts and outer hair cell losses than the control group. The cochleae treated with KX1-141 and KX2-328 did not show statistically significant protection from the impulse noise. The finding of protection with KX2-329 demonstrates that a biaryl-based Src inhibitor has protective capacity against noise-induced hearing loss that is as good as that demonstrated by KX1-004, a Src inhibitor drug that has been studied extensively as an otoprotectant against noise, and suggests that KX2-329 could be useful for protection against noise. PMID:21840347

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

    PubMed

    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

  10. 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, 1.57–3.31) 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

  11. Inhibitor of apoptosis signal-regulating kinase 1 protects against acetaminophen-induced liver injury

    SciTech Connect

    Xie, Yuchao; Ramachandran, Anup; Breckenridge, David G.; Liles, John T.; Lebofsky, Margitta; Farhood, Anwar; Jaeschke, Hartmut

    2015-07-01

    Metabolic activation and oxidant stress are key events in the pathophysiology of acetaminophen (APAP) hepatotoxicity. The initial mitochondrial oxidative stress triggered by protein adduct formation is amplified by c-jun-N-terminal kinase (JNK), resulting in mitochondrial dysfunction and ultimately cell necrosis. Apoptosis signal-regulating kinase 1 (ASK1) is considered the link between oxidant stress and JNK activation. The objective of the current study was to assess the efficacy and mechanism of action of the small-molecule ASK1 inhibitor GS-459679 in a murine model of APAP hepatotoxicity. APAP (300 mg/kg) caused extensive glutathione depletion, JNK activation and translocation to the mitochondria, oxidant stress and liver injury as indicated by plasma ALT activities and area of necrosis over a 24 h observation period. Pretreatment with 30 mg/kg of GS-459679 almost completely prevented JNK activation, oxidant stress and injury without affecting the metabolic activation of APAP. To evaluate the therapeutic potential of GS-459679, mice were treated with APAP and then with the inhibitor. Given 1.5 h after APAP, GS-459679 was still protective, which was paralleled by reduced JNK activation and p-JNK translocation to mitochondria. However, GS-459679 treatment was not more effective than N-acetylcysteine, and the combination of GS-459679 and N-acetylcysteine exhibited similar efficacy as N-acetylcysteine monotherapy, suggesting that GS-459769 and N-acetylcysteine affect the same pathway. Importantly, inhibition of ASK1 did not impair liver regeneration as indicated by PCNA staining. In conclusion, the ASK1 inhibitor GS-459679 protected against APAP toxicity by attenuating JNK activation and oxidant stress in mice and may have therapeutic potential for APAP overdose patients. - Highlights: • Two ASK1 inhibitors protected against acetaminophen-induced liver injury. • The ASK1 inhibitors protect when used as pre- or post-treatment. • Protection by ASK1 inhibitor is

  12. 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

  13. Bromophenacyl bromide, a phospholipase A2 inhibitor attenuates chemically induced gastroduodenal ulcers in rats

    PubMed Central

    Tariq, Mohammad; Elfaki, Ibrahim; Khan, Haseeb Ahmad; Arshaduddin, Mohammad; Sobki, Samia; Moutaery, Meshal Al

    2006-01-01

    AIM: To study the effect of bromophenacyl bromide (BPB), a phospholipase A2 inhibitor on gastric secretion and to protect chemically induced gastric and duodenal ulcers in rats. METHODS: Acid secretion studies were undertaken in pylorus-ligated rats with BPB treatment (0, 5, 15 and 45 mg/kg). Gastric and duodenal lesions in the rats were induced by ethanol and cysteamine respectively. The levels of gastric wall mucus, nonprotein sulfhydryls (NP-SH) and myeloperoxidase (MPO) were also measured in the glandular stomach of rats following ethanol induced gastric lesions. RESULTS: BPB produced a dose-dependent inhibition of gastric acid secretion and acidity in rats. Pretreatment with BPB significantly attenuated the formation of ethanol induced gastric lesion. BPB also protected intestinal mucosa against cysteamine-induced duodenal ulcers. The antiulcer activity of BPB was associated with significant inhibition of ethanol-induced depletion of gastric wall mucus, NP-SH and MPO. These findings pointed towards the mediation of sulfhydryls in BPB induced gastrointestinal cytoprotection. CONCLUSION: BPB possesses significant antiulcer and cytoprotective activity against experimentally induced gastroduodenal lesions. PMID:17007045

  14. CTA095, a novel Etk and Src dual inhibitor, induces apoptosis in prostate cancer cells and overcomes resistance to Src inhibitors.

    PubMed

    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

  15. Detrimental Effect of the Proteasome Inhibitor, Bortezomib in Bacterial Superantigen- and Lipopolysaccharide-induced Systemic Inflammation

    PubMed Central

    Tilahun, Ashenafi Y; Theuer, Jayne E; Patel, Robin; David, Chella S; Rajagopalan, Govindarajan

    2010-01-01

    Bacterial superantigen (BSAg)–induced toxic shock syndrome (TSS) and bacterial lipopolysaccharide (LPS)–induced shock are characterized by severe systemic inflammation. As nuclear factor κB (NFκB) plays an important role in inflammation and bortezomib, a proteasome inhibitor widely used in cancer chemotherapy, is a potent inhibitor of NFκB activation, we evaluated the therapeutic and prophylactic use of bortezomib in these conditions using murine models. Bortezomib prophylaxis significantly reduced serum levels of many cytokines and chemokines induced by BSAg. However, at 3 hours, serum level of TNF-a, an important cytokine implicated in TSS, was significantly reduced but not abolished. At 6 hours, there was no difference in the serum TNF-a levels between bortezomib treated and untreated mice challenged with staphylococcal enterotoxin B (SEB). Paradoxically, all mice treated with bortezomib either before or after BSAg challenge succumbed to TSS. Neither bortezomib nor BSAg was lethal if given alone. Serum biochemical parameters and histopathological findings suggested acute liver failure as the possible cause of mortality. Liver tissue from SEB-challenged mice treated with bortezomib showed a significant reduction in NFκB activation. Because NFκB-dependent antiapoptotic pathways protect hepatocytes from TNF-α-induced cell death, inhibition of NFκB brought forth by bortezomib in the face of elevated TNF-α levels caused by BSAg or LPS is detrimental. PMID:20372109

  16. Detrimental effect of the proteasome inhibitor, bortezomib in bacterial superantigen- and lipopolysaccharide-induced systemic inflammation.

    PubMed

    Tilahun, Ashenafi Y; Theuer, Jayne E; Patel, Robin; David, Chella S; Rajagopalan, Govindarajan

    2010-06-01

    Bacterial superantigen (BSAg)-induced toxic shock syndrome (TSS) and bacterial lipopolysaccharide (LPS)-induced shock are characterized by severe systemic inflammation. As nuclear factor kappaB (NF kappaB) plays an important role in inflammation and bortezomib, a proteasome inhibitor widely used in cancer chemotherapy, is a potent inhibitor of NF kappaB activation, we evaluated the therapeutic and prophylactic use of bortezomib in these conditions using murine models. Bortezomib prophylaxis significantly reduced serum levels of many cytokines and chemokines induced by BSAg. However, at 3 hours, serum level of TNF-a, an important cytokine implicated in TSS, was significantly reduced but not abolished. At 6 hours, there was no difference in the serum TNF-a levels between bortezomib treated and untreated mice challenged with staphylococcal enterotoxin B (SEB). Paradoxically, all mice treated with bortezomib either before or after BSAg challenge succumbed to TSS. Neither bortezomib nor BSAg was lethal if given alone. Serum biochemical parameters and histopathological findings suggested acute liver failure as the possible cause of mortality. Liver tissue from SEB-challenged mice treated with bortezomib showed a significant reduction in NF kappaB activation. Because NF kappaB-dependent antiapoptotic pathways protect hepatocytes from TNF-alpha-induced cell death, inhibition of NF kappaB brought forth by bortezomib in the face of elevated TNF-alpha levels caused by BSAg or LPS is detrimental. PMID:20372109

  17. Histone deacetylase inhibitors and transforming growth factor-beta induce 15-hydroxyprostaglandin dehydrogenase expression in human lung adenocarcinoma cells.

    PubMed

    Tong, Min; Ding, Yunfei; Tai, Hsin-Hsiung

    2006-09-14

    Histone deacetylase (HDAC) inhibitors have been actively exploited as potential anticancer agents. To identify gene targets of HDAC inhibitors, we found that HDAC inhibitors such as sodium butyrate, scriptaid, apicidin and oxamflatin induced the expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a potential cyclooxygenase-2 (COX-2) antagonist and tumor suppressor, in a time and concentration dependent manner in A549 and H1435 lung adenocarcinoma cells. Detailed analyses indicated that HDAC inhibitors activated the 15-PGDH promoter-luciferase reporter construct in transfected A549 cells. A representative HDAC inhibitor, scriptaid, and its negative structural analog control, nullscript, were further evaluated at the chromatin level. Scriptaid but not nullscript induced a significant accumulation of acetylated histones H3 and H4 which were associated with the 15-PGDH promoter as determined by chromatin immunoprecipitation assay. Transforming growth factor-beta1 (TGF-beta1) also induced the expression of 15-PGDH in a time and concentration dependent manner in A549 and H1435 cells. Induction of 15-PGDH expression by TGF-beta1 was synergistically stimulated by the addition of Wnt3A which was inactive by itself. However, combination of TGF-beta and an HDAC inhibitor, scriptaid, only resulted in an additive effect. Together, our results indicate that 15-PGDH is one of the target genes that HDAC inhibitors and TGF-beta may induce to exhibit tumor suppressive effects. PMID:16844092

  18. Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis

    PubMed Central

    Liu, Ziyi; Cao, Zongxian; Jourdan, Tony; Erdelyi, Katalin; Godlewski, Grzegorz; Szanda, Gergő; Liu, Jie; Park, Joshua K.; Mukhopadhyay, Bani; Rosenberg, Avi Z.; Liow, Jeih-San; Lorenz, Robin G.; Pacher, Pal; Innis, Robert B.; Kunos, George

    2016-01-01

    Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment. Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis. CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects. Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases. Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group. In mouse models of fibrosis induced by CCl4 or bile duct ligation, the hybrid CB1R/iNOS antagonist surpassed the antifibrotic efficacy of the CB1R antagonist rimonabant or the iNOS inhibitor 1400W, without inducing anxiety-like behaviors or CB1R occupancy in the CNS. The hybrid inhibitor also targeted CB1R-independent, iNOS-mediated profibrotic pathways, including increased PDGF, Nlrp3/Asc3, and integrin αvβ6 signaling, as judged by its ability to inhibit these pathways in cnr1−/− but not in nos2−/− mice. Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis. PMID:27525312

  19. 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

  20. Interferon-α and cyclooxygenase-2 inhibitor cooperatively mediates TRAIL-induced apoptosis in hepatocellular carcinoma

    SciTech Connect

    Zuo, Chaohui; Qiu, Xiaoxin; Liu, Nianli; Yang, Darong; Xia, Man; Liu, Jingshi; Wang, Xiaohong; and others

    2015-05-01

    Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Interferon-alpha (IFN-α) has recently been recognized to harbor therapeutic potential in the prevention and treatment of HCC, but it remains controversial as to whether IFN-α exerts direct cytotoxicity against HCC. Cyclooxygenase-2 (COX-2) is overexpressed in HCC and is considered to play a role in hepatocarcinogenesis. Therefore, we aimed to elucidate the combined effect of a COX-2 inhibitor, celecoxib, and IFN-α on in vitro growth suppression of HCC using the hepatoma cell line HLCZ01 and the in vivo nude mouse xenotransplantation model using HLCZ01 cells. Treatment with celecoxib and IFN-α synergistically inhibited cell proliferation in a dose- and time-dependent manner. Apoptosis was identified by 4',6-diamidino-2-phenylindole dihydrochloride and fluorescent staining. IFN-α upregulated the expression of TRAIL, while celecoxib increased the expression of TRAIL receptors. The combined regimen with celecoxib and IFN-α reduced the growth of xenotransplanted HCCs in nude mice. The regulation of IFN-α- and COX-2 inhibitor-induced cell death is impaired in a subset of TRAIL-resistant cells. The molecular mechanisms of HCC cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. Interferon-α and the COX-2 inhibitor celecoxib synergistically increased TRAIL-induced apoptosis in hepatocellular carcinoma. These data suggest that IFN-α and celecoxib may offer a novel role with important implications in designing new therapeutics for TRAIL-resistant tumors. - Highlights: ●The cytotoxic effect of TRAIL on a developed HCC HLCZ01 cells infected with HBV. ●IFN-α and celecoxib induced apoptosis in HLCZ01 cells infected with HBV. ●The combined regime reduced the growth of xenotransplanted HCCs in nude mice model.

  1. ACE inhibitors can induce circulating antibodies directed to antigens of the superficial epidermal cells.

    PubMed

    Cozzani, Emanuele; Rosa, Gian Marco; Drosera, Massimo; Intra, Chiara; Barsotti, Antonio; Parodi, Aurora

    2011-07-01

    Drug-induced pemphigus has been reported in patients receiving angiotensin-converting enzyme inhibitors. The aim of this work was to study a group of hypertensive patients without skin diseases treated with angiotensin-converting enzyme (ACE) Inhibitors (I), to verify the presence of serum circulating anti-antibodies. The indirect immunofluorescence showed that 33 sera (52.38%) presented autoantibodies directed to an antigen of the cytoplasm of the superficial epidermal keratinocytes. Two of the 33 positive sera had antibodies to Dsg1 and/or 3 in ELISA. Immunoblot analyses were negative. All the 48 control sera were found to have no circulating antibodies using the three assays. Our results would confirm that ACEI drugs may trigger the production of circulating autoantibodies also in patients without clinical manifestations of pemphigus. PMID:20563876

  2. Hypoxia inducible factor 1α 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-1α (HIF-1α) has been shown to be a major regulator of the response to low oxygen. In this study, we examined HIF-1α expression in canine lymphoma using cell lines and clinical samples and found that these cells expressed HIF-1α. Moreover, the HIF-1α 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-1α contributes to the proliferation and/or survival of canine lymphoma cells. Therefore, HIF-1α inhibitors may be potential agents to treat canine lymphoma. PMID:26050843

  3. Acute abdomen due to intestinal angioedema induced by ACE inhibitors: not so rare?

    PubMed

    Dobbels, P; Van Overbeke, L; Vanbeckevoort, D; Hiele, M

    2009-01-01

    During the last 5 years we identified 7 patients with a history of episodic acute abdominal pain and subobstruction due to intestinal angioedema secondary to the use of Angiotensin Converting Enzyme (ACE) inhibitors. These cases were all diagnosed in one gastroenterology department. This is thereby the largest single centre case series of ACE inhibitor-induced angioedema that has been published until now. Our findings suggest that this syndrome is far more frequent than international literature would let us believe. We also describe one of the first male cases diagnosed with this entity for which there is a significant female predominance. In the presence of an appropriate history and suggestive findings on CT scan, this diagnosis can relatively easily be made if one is sufficiently intent on it. An appropriate diagnosis can save these patients a lot of unnecessary diagnostic procedures and discomfort. PMID:20163043

  4. A dual inhibitor of cyclooxygenase and 5-lipoxygenase protects against kainic acid-induced brain injury.

    PubMed

    Minutoli, Letteria; Marini, Herbert; Rinaldi, Mariagrazia; Bitto, Alessandra; Irrera, Natasha; Pizzino, Gabriele; Pallio, Giovanni; Calò, Margherita; Adamo, Elena Bianca; Trichilo, Vincenzo; Interdonato, Monica; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica

    2015-06-01

    Systemic administration of kainic acid causes inflammation and apoptosis in the brain, resulting in neuronal loss. Dual cyclooxygenase/5-lipoxygenase (COX/5-LOX) inhibitors could represent a possible neuroprotective approach in preventing glutamate excitotoxicity. Consequently, we investigated the effects of a dual inhibitor of COX/5-LOX following intraperitoneal administration of kainic acid (KA, 10 mg/kg) in rats. Animals were randomized to receive either the dual inhibitor of COX/5-LOX (flavocoxid, 20 mg/kg i.p.) or its vehicle (1 ml/kg i.p.) 30 min after KA administration. Sham brain injury rats were used as controls. We evaluated protein expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2) and tumor necrosis factor alpha (TNF-α) as well as levels of malondialdehyde (MDA), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the hippocampus. Animals were also observed for monitoring behavioral changes according to Racine Scale. Finally, histological analysis and brain edema evaluation were carried out. Treatment with the dual inhibitor of COX/5-LOX decreased protein expression of p-ERK1/2 and TNF-α in hippocampus, markedly reduced MDA, LTB4 and PGE2 hippocampal levels, and also ameliorated brain edema. Histological analysis showed a reduction in cell damage in rats treated with the dual inhibitor of COX/5-LOX, particularly in hippocampal subregion CA3c. Moreover, flavocoxid significantly improved behavioral signs following kainic acid administration. Our results suggest that dual inhibition of COX/5-LOX by flavocoxid has neuroprotective effects during kainic acid-induced excitotoxicity. PMID:25893744

  5. Evidence that peroxisomal acyl-CoA synthetase is located at the cytoplasmic side of the peroxisomal membrane.

    PubMed Central

    Mannaerts, G P; Van Veldhoven, P; Van Broekhoven, A; Vandebroek, G; Debeer, L J

    1982-01-01

    1. Subfractionation by isopycnic density-gradient centrifugation in self-generating Percoll gradients of peroxisome-rich fractions prepared by differential centrifugation confirmed the presence of acyl-CoA synthetase in peroxisomes. Peroxisomes did not contain nicotinamide or adenine nucleotides other than CoA. 2. The gradient fractions most enriched in peroxisomes were pooled and the peroxisomes sedimented by centrifugation, resulting in a 50-fold-purified peroxisomal preparation as revealed by marker enzyme analysis. 3. Palmitate oxidation by intact purified peroxisomes was CoA-dependent, whereas palmitoyl-CoA oxidation was not, demonstrating that the peroxisomal CoA was available for the thiolase reaction, located in the peroxisomal matrix, but not for acyl-CoA synthetase. This suggests that the latter enzyme is located at the cytoplasmic side of the peroxisomal membrane. 4. Additional evidence for this location of peroxisomal acyl-CoA synthetase was as follows. Mechanical disruption of purified peroxisomes resulted in the release of catalase from the broken organelles, but not of acyl-CoA synthetase, indicating that the enzyme was membrane-bound. Acyl-CoA synthetase was not latent, despite the fact that at least one of its substrates appears to have a limited membrane permeability, as evidenced by the presence of CoA in purified peroxisomes. Finally, Pronase, a proteinase that does not penetrate the peroxisomal membrane, almost completely inactivated the acyl-CoA synthetase of intact peroxisomes. PMID:7115321

  6. [Aromatase inhibitor letrozole induces sex inversion in the protogynous red spotted grouper (Epinephelus akaara).].

    PubMed

    Li, Guang-Li; Liu, Xiao-Chun; Lin, Hao-Ran

    2005-08-25

    The objective of this study was to investigate the effects of the aromatase inhibitor (AI) letrozole on gonadal development, serum steroids and aromatase activities in 2-year-old female red spotted grouper (Epinephelus akaara) during reproductive season. Groupers were divided into two groups, one implanted with aromatase inhibitor (AI, 5 mg/kg body weight) and the other elastomer without AI into peritoneal cavity once every four weeks for 8 weeks. Spermiation was checked through gentle abdominal pressure every 2 weeks. Blood samples were obtained from 6 fish of each group every 4 weeks for later analysis of sex steroids. After blood samples were collected, forebrain, midbrain, hindbrain, and gonads were collected and stored at -70 degrees C for later aromatase activity measurement and gonadal histological study. Significantly lower gondadosomatic index (GSI) was observed in AI-implanted group. Fish implanted with AI once showed complete degradation of oocytes and sex inversion with developing testicular tissues in the 4th week. AI induced females to develop into functional males with authentic males testes similar in structure to those in normal males. Spermiating rate of AI-treated males were 14.3%, 35.3%, and 48.4%in the 4th, 6th, and 8th week, respectively, while all fish in the control group were still female with developing ovaries. Aromatase activities in gonads decreased significantly after implantation with aromatase inhibitor, but showed no significant difference between control and AI-implanted group. No difference in serum testosterone (T) levels was observed in control and AI-treated group, while serum levels of 17beta-estradiol (E(2)) decreased but 11-ketotestosterone (11-KT) concentration increased significantly. The present results suggest that the decrease in serum 17beta-estradiol (E(2)) and increase in 11-KT levels may be important for sex inversion induced by aromatase inhibitor in red spotted grouper. PMID:16094495

  7. Microporation is an efficient method for siRNA-induced knockdown of PEX5 in HepG2 cells: evaluation of the transfection efficiency, the PEX5 mRNA and protein levels and induction of peroxisomal deficiency.

    PubMed

    Ahlemeyer, Barbara; Vogt, Julia-Franziska; Michel, Vera; Hahn-Kohlberger, Petra; Baumgart-Vogt, Eveline

    2014-11-01

    The pathomechanism of peroxisomal biogenesis disorders (PBDs), a group of inherited autosomal recessive diseases with mutations of peroxin (PEX) genes, is not yet fully understood. Therefore, several knockout models, e.g., the PEX5 knockout mouse, have been generated exhibiting a complete loss of peroxisomal function. In this study, we wanted to knockdown PEX5 using the siRNA technology (1) to mimic milder forms of PBDs in which the mutated peroxin has some residual function and (2) to analyze the cellular consequences of a reduction of the PEX5 protein without adaption during the development as it is the case in a knockout animal. First, we tried to optimize the transfection of the hepatoma cell line HepG2 with PEX5 siRNA using different commercially available liposomal and non-liposomal transfection reagents (Lipofectamine(®) 2000, FuGENE 6, HiPerFect(®), INTERFERin™, RiboJuice™) as well as microporation using the Neon™ Transfection system. Microporation was found to be superior to the transfection reagents with respect to the transfection efficiency (100 vs. 0-70%), to the reduction of PEX5 mRNA (by 90 vs. 0-50%) and PEX5 protein levels (by 70 vs. 0-50%). Interestingly, we detected that a part of the cleaved PEX5 mRNA still existed as 3' fragment (15%) 24 h after microporation. Using microporation, we further analyzed whether the reduced PEX5 protein level impaired peroxisomal function. We indeed detected a reduced targeting of SKL-tagged proteins into peroxisomes as well as an increased oxidative stress as found in PBD patients and respective knockout mouse models. Knockdown of the PEX5 protein and functional consequences were at a maximum 48 h after microporation. Thereafter, the PEX5 protein was resynthesized, which may allow the temporal analysis of the loss as well as the reconstitution of peroxisomes in the future. In conclusion, we propose microporation as an efficient and reproducible method to transfect HepG2 cells with PEX5 siRNA. We succeeded

  8. 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.

  9. 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.

  10. Inhibitors of adriamycin-induced histamine release in vitro limit adriamycin cardiotoxicity in vivo.

    PubMed Central

    Klugmann, F. B.; Decorti, G.; Candussio, L.; Grill, V.; Mallardi, F.; Baldini, L.

    1986-01-01

    The activity of theophylline and disodium cromoglycate was tested on adriamycin-induced histamine release in vitro and on adriamycin cardiotoxicity in vivo. Both substances significantly inhibited the release of histamine induced by 100 micrograms ml-1 of adriamycin on rat peritoneal cells and produced significant protection against adriamycin-mediated acute and chronic cardiotoxicity in mice. N-acetylcysteine, a free radical scavenger, successfully used in the prevention of the cardiomyopathy, was also found to be an inhibitor of histamine release induced by adriamycin and compound 48/80 on rat peritoneal cells. This study further supports the hypothesis that the release of histamine may be involved in the pathogenesis of anthracycline cardiotoxicity. Images Figure 5 Figure 6 Figure 7 Figure 8 PMID:2432914

  11. 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 ERα, HER2, and HIF-1α (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 ERα to elucidate the regulation of HIF-1 and BCRP. Lastly, cells were treated with inhibitors or inducers of HIF-1α to determine its importance. Results Basal HIF-1α 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-1α 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

  12. Acquisition and reinstatement of ethanol-induced conditioned place preference in rats: Effects of the cholinesterase inhibitors donepezil and rivastigmine.

    PubMed

    Gawel, Kinga; Labuz, Krzysztof; Gibula-Bruzda, Ewa; Jenda, Malgorzata; Marszalek-Grabska, Marta; Silberring, Jerzy; Kotlinska, Jolanta H

    2016-07-01

    The present study examined the influence of the cholinesterase inhibitors donepezil (a selective inhibitor of acetylcholinesterase) and rivastigmine (also an inhibitor of butyrylcholinesterase) on the acquisition and reinstatement of ethanol-induced conditioned place preference (CPP) in rats. Before the CPP procedure, animals received a single injection of ethanol (0.5 g/kg, 10% w/v, intraperitoneally [i.p.]) for 15 days. The ethanol-induced CPP (biased method) was developed by four injections of ethanol (0.5 g/kg, 10% w/v, i.p.) every second day. Control rats received saline instead of ethanol. Donepezil (0.5, 1 or 3 mg/kg, i.p.) or rivastigmine (0.03, 0.5 or 1 mg/kg, i.p.) were administered before ethanol during conditioning or before the reinstatement of ethanol-induced CPP. The cholinesterase inhibitors were equally effective in increasing (dose dependently) the acquisition of ethanol-induced CPP. Furthermore, priming injections of both inhibitors reinstated (cross-reinstatement) the ethanol-induced CPP with similar efficacy. These effects of both cholinesterase inhibitors were reversed by mecamylamine (3 mg/kg, i.p.), a nicotinic acetylcholine receptor antagonist, but not by scopolamine (0.5 mg/kg, i.p.), a muscarinic acetylcholine receptor antagonist. Thus, our results show that the cholinergic system is involved in the reinforcing properties of ethanol, and nicotinic acetylcholine receptors play an important role in the relapse to ethanol-seeking behaviour. PMID:27097732

  13. Effects of addition of a dipeptidyl peptidase IV inhibitor to metformin on sirolimus-induced diabetes mellitus.

    PubMed

    Jin, Long; Lim, Sun Woo; Jin, Jian; Chung, Byung Ha; Yang, Chul Woo

    2016-08-01

    The guideline for the management of new-onset diabetes after transplantation recommends metformin (MET) as a first-line drug, and addition of a second-line drug is needed to better control of hyperglycemia. We tested the effect of addition of a dipeptidyl peptidase IV (DPP IV) inhibitor to MET on sirolimus (SRL)-induced diabetes mellitus (DM). In animal model of SRL-induced DM, MET treatment improved pancreatic islet function (blood glucose level and insulin secretion) and attenuated oxidative stress and apoptotic cell death. Addition of a DPP IV inhibitor to MET improved these parameters more than MET alone. An in vitro study showed that SRL treatment increased pancreas beta cell death and production of reactive oxygen species (ROS), and pretreatment of ROS inhibitor, or p38MAPK inhibitor effectively decreased SRL-induced islet cell death. Exendin-4 (EXD), a substrate of DPP IV or MET significantly improved cell viability and decreased ROS production compared with SRL treatment, and combined treatment with the 2 drugs improved both parameters. At the subcellular level, impaired mitochondrial respiration by SRL were partially improved by MET or EXD and much improved further after addition of EXD to MET. Our data suggest that addition of a DPP IV inhibitor to MET decreases SRL-induced oxidative stress and improves mitochondrial respiration. This finding provides a rationale for the combined use of a DPP IV inhibitor and MET in treating SRL-induced DM. PMID:27059001

  14. An inventory of peroxisomal proteins and pathways in Drosophila melanogaster

    PubMed Central

    Faust, Joseph E.; Verma, Avani; Peng, Chengwei; McNew, James A.

    2012-01-01

    Peroxisomes are ubiquitous organelles housing a variety of essential biochemical pathways. Peroxisome dysfunction causes a spectrum of human diseases known as peroxisome biogenesis disorders (PBD). While much is known regarding the mechanism of peroxisome biogenesis, it is still unclear how peroxisome dysfunction leads to the disease state. Several recent studies have shown that mutations in Drosophila peroxin genes cause phenotypes similar to those seen in humans with PBDs suggesting that Drosophila might be a useful system to model PBDs. We have analyzed the proteome of Drosophila to identify the proteins involved in peroxisomal biogenesis and homeostasis as well as metabolic enzymes that function within the organelle. The subcellular localization of five of these predicted peroxisomal proteins was confirmed. Similar to C. elegans, Drosophila appears to only utilize the peroxisome targeting signal (PTS) type 1 system for matrix protein import. This work will further our understanding of peroxisomes in Drosophila and add to the usefulness of this emerging model system. PMID:22758915

  15. 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 PMID:27019559

  16. AKT inhibitor suppresses hyperthermia-induced Ndrg2 phosphorylation in gastric cancer cells

    PubMed Central

    Tao, Yurong; Guo, Yan; Liu, Wenchao; Zhang, Jian; Li, Xia; Shen, Lan; Ru, Yi; Xue, Yan; Zheng, Jin; Liu, Xinping; Zhang, Jing; Yao, Libo

    2013-01-01

    Hyperthermia is one of the most effective adjuvant treatments for various cancers with few side effects. However, the underlying molecular mechanisms still are not known. N-myc downstream-regulated gene 2 (NDRG2), a tumor suppressor, has been shown to be involved in diverse cellular stresses including hypoxia, lipotoxicity, etc. In addition, Ndrg2 has been reported to be related to progression of gastric cancer. In the current study, our data showed that the apoptosis rate of MKN28 cells increased relatively rapidly to 13.4% by 24 h after treatment with hyperthermia (42°C for 1 h) compared to 5.1% in control cells (P < 0.05). Nevertheless, there was no obvious change in the expression level of total Ndrg2 during this process. Further investigation demonstrated that the relative phosphorylation levels of Ndrg2 at Ser332, Thr348 increased up to 3.2- and 1.9-fold (hyperthermia group vs control group) at 3 h in MKN28 cells, respectively (P < 0.05). We also found that heat treatment significantly increased AKT phosphorylation. AKT inhibitor VIII (10 µM) decreased the phosphorylation level of Ndrg2 induced by hyperthermia. Accordingly, the apoptosis rate rose significantly in MKN28 cells (16.4%) treated with a combination of AKT inhibitor VIII and hyperthermia compared to that (6.8%) of cells treated with hyperthermia alone (P < 0.05). Taken together, these data demonstrated that Ndrg2 phosphorylation could be induced by hyperthermia in an AKT-dependent manner in gastric cancer cells. Furthermore, AKT inhibitor VIII suppressed Ndrg2 phosphorylation and rendered gastric cancer cells susceptible to apoptosis induced by hyperthermia. PMID:23558861

  17. HDAC inhibitors induce epithelial-mesenchymal transition in colon carcinoma cells.

    PubMed

    Ji, Meiying; Lee, Eun Jeoung; Kim, Ki Bae; Kim, Yangmi; Sung, Rohyun; Lee, Sang-Jeon; Kim, Don Soo; Park, Seon Mee

    2015-05-01

    The effects of histone deacetylase (HDAC) inhibitors on epithelial-mesenchymal transition (EMT) differ in various types of cancers. We investigated the EMT phenotype in four colon cancer cell lines when challenged with HDAC inhibitors trichostatin A (TSA) and valproic acid (VPA) with or without transforming growth factor-β1 (TGF-β1) treatment. Four colon cancer cell lines with different phenotypes in regards to tumorigenicity, microsatellite stability and DNA mutation were used. EMT phenotypes were assessed by the expression of E-cadherin and vimentin using western blot analysis, immunofluorescence, quantitative real-time RT-PCR following treatment with TSA (100 or 200 nM) or VPA (0.5 mM) with or without TGF-β1 (5 ng/ml) for 24 h. Biological EMT phenotypes were also evaluated by cell morphology, migration and invasion assays. TSA or VPA induced mesenchymal features in the colon carcinoma cells by a decrease in E-cadherin and an increase in vimentin expression at the mRNA and protein levels. Confocal microscopy revealed membranous attenuation or nuclear translocation of E-cadherin and enhanced expression of vimentin. These responses occurred after 6 h and increased until 24 h. Colon cancer cells changed from a round or rectangular shape to a spindle shape with increased migration and invasion ability following TSA or VPA treatment. The susceptibility to EMT changes induced by TSA or VPA was comparable in microsatellite stable (SW480 and HT29) and microsatellite unstable cells (DLD1 and HCT116). TSA or VPA induced a mesenchymal phenotype in the colon carcinoma cells and these effects were augmented in the presence of TGF-β1. HDAC inhibitors require careful caution before their application as new anticancer drugs for colon cancers. PMID:25813246

  18. Cholinesterase inhibitors ameliorate behavioral deficits induced by MK-801 in mice.

    PubMed

    Csernansky, John G; Martin, Maureen; Shah, Renu; Bertchume, Amy; Colvin, Jenny; Dong, Hongxin

    2005-12-01

    Enhancing cholinergic function has been suggested as a possible strategy for ameliorating the cognitive deficits of schizophrenia. The purpose of this study was to examine the effects of acetylcholinesterase (AChE) inhibitors in mice treated with the noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, which has been suggested as an animal model of the cognitive deficits of schizophrenia. Three separate experiments were conducted to test the effects of physostigmine, donepezil, or galantamine on deficits in learning and memory induced by MK-801. In each experiment, MK-801 (0.05 or 0.10 mg/kg) or saline was administered i.p. 20 min prior to behavioral testing over a total of 12 days. At 30 min prior to administration of MK-801 or saline, one of three doses of the AChE inhibitor (ie physostigmine-0.03, 0.10, or 0.30 mg/kg; donepezil-0.10, 0.30, or 1.00 mg/kg; or galantamine-0.25, 0.50, or 1.00 mg/kg) or saline was administered s.c. Behavioral testing was performed in all experimental animals using the following sequence: (1) spatial reversal learning, (2) locomotion, (3) fear conditioning, and (4) shock sensitivity. Both doses of MK-801 produced impairments in spatial reversal learning and in contextual and cued memory, as well as hyperlocomotion. Physostigmine and donepezil, but not galantamine, ameliorated MK-801-induced deficits in spatial reversal learning and in contextual and cued memory in a dose-dependent manner. Also, physostigmine, but not donepezil or galantamine, reversed MK-801-induced hyperlocomotion. Galantamine, but not physostigmine or donepezil, altered shock sensitivity. These results suggest that AChE inhibitors may differ in their capacity to ameliorate learning and memory deficits produced by MK-801 in mice, which may have relevance for the cognitive effects of cholinomimetic drugs in patients with schizophrenia. PMID:15956997

  19. 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

  20. 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

  1. 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

  2. The gene coding for the mustard trypsin inhibitor-2 is discontinuous and wound-inducible.

    PubMed

    Ceci, L R; Spoto, N; de Virgilio, M; Gallerani, R

    1995-05-01

    The gene coding for the mustard trypsin inhibitor-2 has been isolated from a genomic library and characterized. Comparison of genomic and cDNA sequences indicates that the gene is interrupted by an intron of 193 bp. The eukaryotic peculiar regulatory sequences have been detected in the 5' flanking region of the gene. In addition, a decanucleotide has been detected that is highly similar to the proposed G-box and to the ABRE motifs required for the gene expression induced by methyl jasmonate and abscissic acid. Northern blot analysis demonstrates that the gene is expressed in immature seeds as well as in wounded leaves. PMID:7750566

  3. Effects of lipoxygenase inhibitors in a model of lens-induced uveitis in dogs.

    PubMed

    Dziezyc, J; Millichamp, N J; Rohde, B H; Baker, J S; Chiou, G C

    1989-11-01

    Uveitis was induced in dogs by intracameral injection of canine lens protein. The lipoxygenase inhibitors phenidone and norhydroguaiaretic acid, and dimethyl sulfoxide decreased fibrin production at 0.5 and 1 hour after induction of uveitis. Phenidone and norhydroguaiaretic acid also inhibited the initial increase in intraocular pressure early in the course of inflammation. Leukotriene B4 in the aqueous was measured by use of radioimmunoassay at 1 hour after inflammation. In control dogs, 230 to 1,700 pg of leukotriene B4/ml was measured; in dogs treated with phenidone, leukotriene B4 was not measured. PMID:2515781

  4. Arabidopsis PEROXIN11c-e, FISSION1b, and DYNAMIN-RELATED PROTEIN3A Cooperate in Cell Cycle–Associated Replication of Peroxisomes[W

    PubMed Central

    Lingard, Matthew J.; Gidda, Satinder K.; Bingham, Scott; Rothstein, Steven J.; Mullen, Robert T.; Trelease, Richard N.

    2008-01-01

    Although participation of PEROXIN11 (PEX11), FISSION1 (FISl), and DYNAMIN-RELATED PROTEIN (DRP) has been well established during induced peroxisome proliferation in response to external stimuli, their roles in cell cycle–associated constitutive replication/duplication have not been fully explored. Herein, bimolecular fluorescence complementation experiments with Arabidopsis thaliana suspension cells revealed homooligomerization of all five PEX11 isoforms (PEX11a-e) and heterooligomerizations of all five PEX11 isoforms with FIS1b, but not FIS1a nor DRP3A. Intracellular protein targeting experiments demonstrated that FIS1b, but not FIS1a nor DRP3A, targeted to peroxisomes only when coexpressed with PEX11d or PEX11e. Simultaneous silencing of PEX11c-e or individual silencing of DRP3A, but not FIS1a nor FIS1b, resulted in ∼40% reductions in peroxisome number. During G2 in synchronized cell cultures, peroxisomes sequentially enlarged, elongated, and then doubled in number, which correlated with peaks in PEX11, FIS1, and DRP3A expression. Overall, these data support a model for the replication of preexisting peroxisomes wherein PEX11c, PEX11d, and PEX11e act cooperatively during G2 to promote peroxisome elongation and recruitment of FIS1b to the peroxisome membrane, where DRP3A stimulates fission of elongated peroxisomes into daughter peroxisomes, which are then distributed between daughter cells. PMID:18539750

  5. 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.

  6. Kidney-specific Overexpression of Sirt1 Protects against Acute Kidney Injury by Retaining Peroxisome Function

    PubMed Central

    Hasegawa, Kazuhiro; Wakino, Shu; Yoshioka, Kyoko; Tatematsu, Satoru; Hara, Yoshikazu; Minakuchi, Hitoshi; Sueyasu, Keiko; Washida, Naoki; Tokuyama, Hirobumi; Tzukerman, Maty; Skorecki, Karl; Hayashi, Koichi; Itoh, Hiroshi

    2010-01-01

    Sirt1, a NAD-dependent protein deacetylase, is reported to regulate intracellular metabolism and attenuate reactive oxidative species (ROS)-induced apoptosis leading to longevity and acute stress resistance. We created transgenic (TG) mice with kidney-specific overexpression of Sirt1 using the promoter sodium-phosphate cotransporter IIa (Npt2) driven specifically in proximal tubules and investigated the kidney-specific role of Sirt1 in the protection against acute kidney injury (AKI). We also elucidated the role of number or function of peroxisome and mitochondria in mediating the mechanisms for renal protective effects of Sirt1 in AKI. Cisplatin-induced AKI decreased the number and function of peroxisomes as well as mitochondria and led to increased local levels of ROS production and renal tubular apoptotic cells. TG mice treated with cisplatin mitigated AKI, local ROS, and renal tubular apoptotic tubular cells. Consistent with these results, TG mice treated with cisplatin also exhibited recovery of peroxisome number and function, as well as rescued mitochondrial function; however, mitochondrial number was not recovered. Immunoelectron microscopic findings consistently demonstrated that the decrease in peroxisome number by cisplatin in wild type mice was restored in transgenic mice. In HK-2 cells, a cultured proximal tubule cell line, overexpression of Sirt1 rescued the cisplatin-induced cell apoptosis through the restoration of peroxisome number, although the mitochondria number was not restored. These results indicate that Sirt1 overexpression in proximal tubules rescues cisplatin-induced AKI by maintaining peroxisomes number and function, concomitant up-regulation of catalase, and elimination of renal ROS levels. Renal Sirt1 can be a potential therapeutic target for the treatment of AKI. PMID:20139070

  7. Roles of Peroxisomes in the Rice Blast Fungus

    PubMed Central

    Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

  8. Roles of Peroxisomes in the Rice Blast Fungus.

    PubMed

    Chen, Xiao-Lin; Wang, Zhao; Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

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

    PubMed

    Karthik, Govindasamy-Muralidharan; Ma, Ran; Lövrot, 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

  10. Saxagliptin: a dipeptidyl peptidase-4 inhibitor ameliorates streptozotocin induced Alzheimer's disease.

    PubMed

    Kosaraju, Jayasankar; Gali, Chaitanya Chakravarthi; Khatwal, Rizwan Basha; Dubala, Anil; Chinni, Santhivardhan; Holsinger, R M Damian; Madhunapantula, V Subba Rao; Muthureddy Nataraj, Satish Kumar; Basavan, Duraiswamy

    2013-09-01

    Type 2 diabetes (T2D) is one of the major risk factors associated with Alzheimer's disease (AD). Recent studies have found similarities in molecular mechanisms that underlie the respective degenerative developments in the two diseases. Pharmacological agents, such as dipeptidyl peptidase-4 (DPP-4) inhibitors, which increase the level of glucagon-like peptide-1 (GLP-1) and ameliorate T2D, have become valuable candidates as disease modifying agents in the treatment of AD. In addition, endogenous GLP-1 levels decrease amyloid beta (Aβ) peptide and tau phosphorylation in AD. The present study examines the efficacy of Saxagliptin, a DPP-4 inhibitor in a streptozotocin (STZ) induced rat model of AD. Three months following induction of AD by intracerebral administration of streptozotocin, animals were orally administered Saxagliptin (0.25, 0.5 and 1 mg/kg) for 60 days. The effect of the DPP-4 inhibitor on hippocampal GLP-1 levels, Aβ burden, tau phosphorylation, inflammatory markers and memory retention were evaluated. The results reveal an attenuation of Aβ, tau phosphorylation and inflammatory markers and an improvement in hippocampal GLP-1 and memory retention following treatment. This remarkable therapeutic effect of Saxagliptin mediated through DPP-4 inhibition demonstrates a unique mechanism for Aβ and tau clearance by increasing GLP-1 levels and reverses the behavioural deficits and pathology observed in AD. PMID:23603201

  11. A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration.

    PubMed

    Ban, Hyun Seung; Xu, Xuezhen; Jang, Kusik; Kim, Inhyub; Kim, Bo-Kyung; Lee, Kyeong; Won, Misun

    2016-01-01

    We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhibited significant growth inhibition of human colorectal cancer HCT116 cells. Compound 7 demonstrated substantial anti-tumor efficacy in an in vivo xenograft assay using HCT116 mouse model. Taken together, a novel MDH2 inhibitor, compound 7, suppressed HIF-1α accumulation via reduction of oxygen consumption and ATP production, integrating metabolism into anti-cancer efficacy in cancer cells. PMID:27611801

  12. Changes of epidermal cell morphology and keratin expression induced by inhibitors of protein kinase C.

    PubMed

    Hegemann, L; Wevers, A; Bonnekoh, B; Mahrle, G

    1992-03-01

    Several lines of evidence show protein kinase C as being involved in various regulatory processes in keratinocyte biology, e.g. proliferation and differentiation. In the present study, we investigated the effects of three different inhibitors of protein kinase C, staurosporine, CP 46'665-1, and tiflucarbine, on cell morphology and keratin expression in a non-tumorigenic human keratinocyte cell line (HaCaT cells). Staurosporine, being the most potent inhibitor of protein kinase C activity in vitro, and CP 46'665-1 induced morphological transformation to a fibroblast-like cell shape. In contrast, no changes in cell morphology were observed after exposure to tiflucarbine. The investigation of keratin expression in HaCaT cells grown in the presence of the different compounds revealed the following changes: After 72 h of cultivation, keratins 8 and 18 were still expressed in treated cells, whereas expression of keratin 13 was decreased as compared to control cells. Immunoblotting to detect vimentin demonstrated its absence in treated and control cells. Since tiflucarbine is known as a dual protein kinase C/calmodulin inhibitor whereas staurosporine and CP 46'665-1 do not antagonize calmodulin function, it might be possible that not only protein kinase C but also calmodulin is involved in the process leading to the morphological changes. PMID:1376142

  13. Anti-Ulcer Efficacy of Soluble Epoxide Hydrolase Inhibitor TPPU on Diclofenac-Induced Intestinal Ulcers

    PubMed Central

    Goswami, Sumanta Kumar; Wan, Debin; Yang, Jun; Trindade da Silva, Carlos A.; Morisseau, Christophe; Kodani, Sean D.; Yang, Guang-Yu; Inceoglu, Bora

    2016-01-01

    Proton pump inhibitors such as omeprazole (OME) reduce the severity of gastrointestinal (GI) ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) but can also increase the chance of dysbiosis. The aim of this study was to test the hypothesis that preventive use of a soluble epoxide hydrolase inhibitor (sEHI) such as TPPU can decrease NSAID-induced ulcers by increasing anti-inflammatory epoxyeicosatrienoic acids (EETs). Dose- [10, 30, and 100 mg/kg, by mouth (PO)] and time-dependent (6 and 18 hours) ulcerative effects of diclofenac sodium (DCF, an NSAID) were studied in the small intestine of Swiss Webster mice. Dose-dependent effects of TPPU (0.001–0.1 mg/kg per day for 7 days, in drinking water) were evaluated in DCF-induced intestinal toxicity and compared with OME (20 mg/kg, PO). In addition, the effect of treatment was studied on levels of Hb in blood, EETs in plasma, inflammatory markers such as myeloperoxidase (MPO) in intestinal tissue homogenates, and tissue necrosis factor-α (TNF-α) in serum. DCF dose dependently induced ulcers that were associated with both a significant (P < 0.05) loss of Hb and an increase in the level of MPO and TNF-α, with severity of ulceration highest at 18 hours. Pretreatment with TPPU dose dependently prevented ulcer formation by DCF, increased the levels of epoxy fatty acids, including EETs, and TPPU’s efficacy was comparable to OME. TPPU significantly (P < 0.05) reversed the effect of DCF on the level of Hb, MPO, and TNF-α. Thus sEHI might be useful in the management of NSAID-induced ulcers. PMID:26989141

  14. Effect of the 5-lipoxygenase inhibitor ZD2138 on aspirin-induced asthma.

    PubMed Central

    Nasser, S. M.; Bell, G. S.; Foster, S.; Spruce, K. E.; MacMillan, R.; Williams, A. J.; Lee, T. H.; Arm, J. P.

    1994-01-01

    BACKGROUND--The cysteinyl leukotrienes may play a central part in the mechanisms of aspirin-sensitive asthma. Previous work has shown that individuals with aspirin-sensitive asthma have high basal urinary LTE4 levels which increase further upon aspirin ingestion, and that sulphidopeptide leukotriene receptor antagonists attenuate aspirin-induced airflow obstruction. If the cysteinyl leukotrienes cause aspirin-induced asthmatic reactions, inhibition of the 5-lipoxygenase pathway should prevent aspirin-induced bronchospasm. This hypothesis has been tested with ZD2138, a specific non-redox 5-lipoxygenase inhibitor. METHODS--Seven subjects (four men) with aspirin-sensitive asthma with baseline FEV1 values > 67% were studied. ZD2138 (350 mg) or placebo was given on two separate occasions two weeks apart in a randomised double blind fashion. A single dose of aspirin was administered four hours after dosing and FEV1 was measured for six hours. Inhibition of the 5-lipoxygenase pathway by ZD2138 was assessed by measurements of urinary LTE4 levels and ex vivo calcium ionophore stimulated LTB4 generation in whole blood, before administration of drug or placebo and at regular time intervals after dosing and aspirin administration. RESULTS--ZD2138 protected against the aspirin-induced reduction in FEV1 with a 20.3 (4.9)% fall in FEV1 following placebo compared with 4.9 (2.9)% following ZD2138. This was associated with 72% inhibition of ex vivo LTB4 generation in whole blood at 12 hours and a 74% inhibition of the rise in urinary LTE4 excretion at six hours after aspirin ingestion. CONCLUSIONS--In aspirin-sensitive asthma the 5-lipoxygenase inhibitor ZD2138 inhibits the fall in FEV1 induced by aspirin and this is associated with substantial inhibition of 5-lipoxygenase. PMID:8091318

  15. 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 (PKCɛ)-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) Hsp90β-PKCɛ interaction, and (3) expression levels of Hsp90β, 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

  16. 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

  17. Anti-Ulcer Efficacy of Soluble Epoxide Hydrolase Inhibitor TPPU on Diclofenac-Induced Intestinal Ulcers.

    PubMed

    Goswami, Sumanta Kumar; Wan, Debin; Yang, Jun; Trindade da Silva, Carlos A; Morisseau, Christophe; Kodani, Sean D; Yang, Guang-Yu; Inceoglu, Bora; Hammock, Bruce D

    2016-06-01

    Proton pump inhibitors such as omeprazole (OME) reduce the severity of gastrointestinal (GI) ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) but can also increase the chance of dysbiosis. The aim of this study was to test the hypothesis that preventive use of a soluble epoxide hydrolase inhibitor (sEHI) such as TPPU can decrease NSAID-induced ulcers by increasing anti-inflammatory epoxyeicosatrienoic acids (EETs). Dose- [10, 30, and 100 mg/kg, by mouth (PO)] and time-dependent (6 and 18 hours) ulcerative effects of diclofenac sodium (DCF, an NSAID) were studied in the small intestine of Swiss Webster mice. Dose-dependent effects of TPPU (0.001-0.1 mg/kg per day for 7 days, in drinking water) were evaluated in DCF-induced intestinal toxicity and compared with OME (20 mg/kg, PO). In addition, the effect of treatment was studied on levels of Hb in blood, EETs in plasma, inflammatory markers such as myeloperoxidase (MPO) in intestinal tissue homogenates, and tissue necrosis factor-α (TNF-α) in serum. DCF dose dependently induced ulcers that were associated with both a significant (P < 0.05) loss of Hb and an increase in the level of MPO and TNF-α, with severity of ulceration highest at 18 hours. Pretreatment with TPPU dose dependently prevented ulcer formation by DCF, increased the levels of epoxy fatty acids, including EETs, and TPPU's efficacy was comparable to OME. TPPU significantly (P < 0.05) reversed the effect of DCF on the level of Hb, MPO, and TNF-α Thus sEHI might be useful in the management of NSAID-induced ulcers. PMID:26989141

  18. 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 Parkinson’s, Alzheimer’s, and Huntington’s 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 Bionet’s 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

  19. 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

  20. 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

  1. Ceramide stimulates ABCA12 expression via peroxisome proliferator-activated receptor {delta} in human keratinocytes.

    PubMed

    Jiang, Yan J; Uchida, Yoshikazu; Lu, Biao; Kim, Peggy; Mao, Cungui; Akiyama, Masashi; Elias, Peter M; Holleran, Walter M; Grunfeld, Carl; Feingold, Kenneth R

    2009-07-10

    ABCA12 (ATP binding cassette transporter, family 12) is a cellular membrane transporter that facilitates the delivery of glucosylceramides to epidermal lamellar bodies in keratinocytes, a process that is critical for permeability barrier formation. Following secretion of lamellar bodies into the stratum corneum, glucosylceramides are metabolized to ceramides, which comprise approximately 50% of the lipid in stratum corneum. Gene mutations of ABCA12 underlie harlequin ichthyosis, a devastating skin disorder characterized by abnormal lamellar bodies and a severe barrier abnormality. Recently we reported that peroxisome proliferator-activated receptor (PPAR) and liver X receptor activators increase ABCA12 expression in human keratinocytes. Here we demonstrate that ceramide (C(2)-Cer and C(6)-Cer), but not C(8)-glucosylceramides, sphingosine, or ceramide 1-phosphate, increases ABCA12 mRNA expression in a dose- and time-dependent manner. Inhibitors of glucosylceramide synthase, sphingomyelin synthase, and ceramidase and small interfering RNA knockdown of human alkaline ceramidase, which all increase endogenous ceramide levels, also increased ABCA12 mRNA levels. Moreover, simultaneous treatment with C(6)-Cer and each of these same inhibitors additively increased ABCA12 expression, indicating that ceramide is an important inducer of ABCA12 expression and that the conversion of ceramide to other sphingolipids or metabolites is not required. Finally, both exogenous and endogenous ceramides preferentially stimulate PPARdelta expression (but not other PPARs or liver X receptors), whereas PPARdelta knockdown by siRNA transfection specifically diminished the ceramide-induced increase in ABCA12 mRNA levels, indicating that PPARdelta is a mediator of the ceramide effect. Together, these results show that ceramide, an important lipid component of epidermis, up-regulates ABCA12 expression via the PPARdelta-mediated signaling pathway, providing a substrate-driven, feed

  2. 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 BI 2536 at subtoxic concentrations synergize to induce apoptosis in RMS cells as confirmed by calculation of combination index (CI). Also, Eribulin/BI 2536 co-treatment is significantly more effective than monotherapy to reduce cell viability and inhibit colony formation of RMS cells. Similarly, Eribulin and BI 2536 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/BI 2536 co-treatment causes profound mitotic arrest, which is critically required for synergism, since inhibition of mitotic arrest by CDK1 inhibitor RO-3306 abolishes Eribulin/BI 2536-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/BI 2536-induced apoptosis significantly, yet partially. Intriguingly, knockdown of endonuclease G (ENDOG) also significantly inhibits Eribulin/BI 2536-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

  3. PredPlantPTS1: A Web Server for the Prediction of Plant Peroxisomal Proteins

    PubMed Central

    Reumann, Sigrun; Buchwald, Daniela; Lingner, Thomas

    2012-01-01

    Prediction of subcellular protein localization is essential to correctly assign unknown proteins to cell organelle-specific protein networks and to ultimately determine protein function. For metazoa, several computational approaches have been developed in the past decade to predict peroxisomal proteins carrying the peroxisome targeting signal type 1 (PTS1). However, plant-specific PTS1 protein prediction methods have been lacking up to now, and pre-existing methods generally were incapable of correctly predicting low-abundance plant proteins possessing non-canonical PTS1 patterns. Recently, we presented a machine learning approach that is able to predict PTS1 proteins for higher plants (spermatophytes) with high accuracy and which can correctly identify unknown targeting patterns, i.e., novel PTS1 tripeptides and tripeptide residues. Here we describe the first plant-specific web server PredPlantPTS1 for the prediction of plant PTS1 proteins using the above-mentioned underlying models. The server allows the submission of protein sequences from diverse spermatophytes and also performs well for mosses and algae. The easy-to-use web interface provides detailed output in terms of (i) the peroxisomal targeting probability of the given sequence, (ii) information whether a particular non-canonical PTS1 tripeptide has already been experimentally verified, and (iii) the prediction scores for the single C-terminal 14 amino acid residues. The latter allows identification of predicted residues that inhibit peroxisome targeting and which can be optimized using site-directed mutagenesis to raise the peroxisome targeting efficiency. The prediction server will be instrumental in identifying low-abundance and stress-inducible peroxisomal proteins and defining the entire peroxisomal proteome of Arabidopsis and agronomically important crop plants. PredPlantPTS1 is freely accessible at ppp.gobics.de. PMID:22969783

  4. The Candida boidinii peroxisomal membrane protein Pmp30 has a role in peroxisomal proliferation and is functionally homologous to Pmp27 from Saccharomyces cerevisiae.

    PubMed Central

    Sakai, Y; Marshall, P A; Saiganji, A; Takabe, K; Saiki, H; Kato, N; Goodman, J M

    1995-01-01

    The mechanism of peroxisome proliferation is poorly understood. Candida boidinii is a methylotrophic yeast that undergoes rapid and massive peroxisome proliferation and serves as a good model system for this process. Pmp30A and Pmp30B (formerly designated Pmp31 and Pmp32, respectively) are two closely related proteins in a polyploid strain of this yeast that are strongly induced by diverse peroxisome proliferators such as methanol, oleate, and D-alanine. The function of these proteins is not understood. To study this issue, we used a recently described haploid strain (S2) of C. boidinii that can be manipulated genetically. We now report that strain S2 contains a single PMP30 gene very similar in sequence (greater than 93% identity at the DNA level) to PMP30A and PMP30B. When PMP30 was disrupted, cell growth on methanol was greatly inhibited, and cells grown in both methanol and oleate had fewer, larger, and more spherical peroxisomes than wild-type cells. A similar phenotype was recently described for Saccharomyces cerevisiae cultured on oleate in which PMP27, which encodes a protein of related sequence that is important for peroxisome proliferation, was disrupted. To determine whether Pmp27 is a functional homolog of Pmp30, gentle complementation was performed. PMP30A was expressed in the PMP27 disruptant of S. cerevisiae, and PMP27 was expressed in the PMP30 disruptant of C. boidinii S2. Complementation, in terms of both cell growth and organelle size, shape, and number, was successful in both directions, although reversion to a wild-type phenotype was only partial for the PMP30 disruptant. We conclude that these proteins are functional homologs and that both Pmp30 and Pmp27 have a direct role in proliferation and organelle size rather than a role in a specific peroxisomal metabolic pathway of substrate utilization. PMID:7592467

  5. Pharmacologic profiling of phosphoinositide 3-kinase inhibitors as mitigators of ionizing radiation-induced cell death.

    PubMed

    Lazo, John S; Sharlow, Elizabeth R; Epperly, Michael W; Lira, Ana; Leimgruber, Stephanie; Skoda, Erin M; Wipf, Peter; Greenberger, Joel S

    2013-12-01

    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 γIR-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 γIR, 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 γIR 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 γIR-induced DNA damage as measured by γH2AX, suggesting reduced DNA damage. These results indicate pharmacologic inhibition of PI3K after

  6. Pharmacologic Profiling of Phosphoinositide 3-Kinase Inhibitors as Mitigators of Ionizing Radiation–Induced 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 γIR-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 γIR, 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 γIR 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 γIR-induced DNA damage as measured by γH2AX, suggesting reduced DNA damage. These results indicate pharmacologic inhibition of PI3K after

  7. Respiratory inhibitors and uncouplers prevent the aeration-induced increase in mitochondrial anion conductivity.

    PubMed Central

    Halle-Smith, S C; Selwyn, M J

    1990-01-01

    1. When mitochondria are stirred in air the rate of anion conductivity increases, this effect being enhanced by the addition of respiratory substrate. 2. This effect is reversible if the mitochondria are stored for a period of time under N2. 3. The aeration-induced increase in mitochondrial anion conductivity can also be prevented by the addition of respiratory inhibitors rotenone and antimycin A, as well as by 30 microM-cyanide. 4. A decrease in this aeration-induced anion conductivity can also be observed upon the addition of the uncouplers carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (2 microM) and 2,4-dinitrophenol (100 microM). 5. Simultaneous measurements of mitochondrial anion conductivity and membrane potential show a relationship between the level of membrane potential and anion conductivity. 6. It is suggested that the level of membrane potential is either directly or indirectly responsible for the level of mitochondrial anion conductivity. PMID:2327957

  8. Respiratory inhibitors and uncouplers prevent the aeration-induced increase in mitochondrial anion conductivity.

    PubMed

    Halle-Smith, S C; Selwyn, M J

    1990-03-15

    1. When mitochondria are stirred in air the rate of anion conductivity increases, this effect being enhanced by the addition of respiratory substrate. 2. This effect is reversible if the mitochondria are stored for a period of time under N2. 3. The aeration-induced increase in mitochondrial anion conductivity can also be prevented by the addition of respiratory inhibitors rotenone and antimycin A, as well as by 30 microM-cyanide. 4. A decrease in this aeration-induced anion conductivity can also be observed upon the addition of the uncouplers carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (2 microM) and 2,4-dinitrophenol (100 microM). 5. Simultaneous measurements of mitochondrial anion conductivity and membrane potential show a relationship between the level of membrane potential and anion conductivity. 6. It is suggested that the level of membrane potential is either directly or indirectly responsible for the level of mitochondrial anion conductivity. PMID:2327957

  9. Cyclooxygenase inhibitor induces the upregulation of connexin-43 expression in C6 glioma cells

    PubMed Central

    QIN, LI-JUAN; JIA, YONG-SEN; ZHANG, YI-BING; WANG, YIN-HUAN

    2016-01-01

    The present study was performed to determine whether aspirin, a cyclooxygenase (COX) inhibitor, has an effect on the expression of connexin 43 (Cx43) in C6 glioma cells. Using an in vitro glioma invasion model, the expression of Cx43 protein in C6 cells was significantly increased following aspirin treatment at a dose of 8 mmol/l for 30, 60 and 120 min via western blot analysis. The peak value of the Cx43 expression was observed in C6 cells after 120 min of aspirin treatment, which was significantly reduced by prostaglandin E2 (PGE2). In addition, aspirin also significantly increased the gap junction intercellular communication (GJIC) activity and reduced glioma invasion, which was induced by PGE2. This led to the conclusion that the aspirin-induced glioma invasion decrease may be associated with the increased expression of Cx43 protein and formation of GJIC. PMID:27073629

  10. KEAP1-dependent synthetic lethality induced by AKT and TXNRD1 inhibitors in lung cancer

    PubMed Central

    Dai, Bingbing; Yoo, Suk-Yuong; Bartholomeusz, Geoffrey; Graham, Ryan A.; Majidi, Mourad; Yan, Shaoyu; Meng, Jieru; Ji, Lin; Coombes, Kevin; Minna, John D.; Fang, Bingliang; Roth, Jack A.

    2013-01-01

    Intrinsic resistance to agents targeting phosphatidylinositol-3-kinase (PI3K)/AKT pathway is one of the major challenges in cancer treatment with such agents. The objective of this study is to identify the genes or pathways that can be targeted to overcome the resistance of non-small cell lung cancer to the AKT inhibitor, MK2206, which is currently being evaluated in phase I and II clinical trials. Using a genome-wide small interfering RNA (siRNA) library screening and biological characterization we identified that inhibition of Thioredoxin Reductase-1 (TXNRD1), one of the key anti-oxidant enzymes, with siRNAs or its inhibitor, Auranofin, sensitized non-small cell lung cancer cells to MK2206 treatment in vitro and in vivo. We found that simultaneous inhibition of TXNRD1 and AKT pathways induced robust reactive oxygen species (ROS) production, which was involved in c-Jun N-terminal Kinase (JNK, MAPK8) activation and cell apoptosis. Furthermore we found that the synthetic lethality interaction between the TXNRD1 and AKT pathways occurred through the KEAP1/NRF2 cellular antioxidant pathway. Lastly, we found that synthetic lethality induced by TXNRD1 and AKT inhibitors relied on wild type KEAP1 function. Our study indicates that targeting the interaction between AKT and TXNRD1 antioxidant pathways with MK2206 and Auranofin, a FDA approved drug, is a rational strategy to treat lung cancer and that KEAP1 mutation status may offer a predicative biomarker for such combination approaches. PMID:23824739

  11. Phenotypic Screening Identifies Protein Synthesis Inhibitors as H-Ras-Nanocluster-Increasing Tumor Growth Inducers.

    PubMed

    Najumudeen, Arafath K; Posada, Itziar M D; Lectez, Benoit; Zhou, Yong; Landor, Sebastian K-J; Fallarero, Adyary; Vuorela, Pia; Hancock, John; Abankwa, Daniel

    2015-12-15

    Ras isoforms H-, N-, and K-ras are each mutated in specific cancer types at varying frequencies and have different activities in cell fate control. On the plasma membrane, Ras proteins are laterally segregated into isoform-specific nanoscale signaling hubs, termed nanoclusters. As Ras nanoclusters are required for Ras signaling, chemical modulators of nanoclusters represent ideal candidates for the specific modulation of Ras activity in cancer drug development. We therefore conducted a chemical screen with commercial and in-house natural product libraries using a cell-based H-ras-nanoclustering FRET assay. Next to established Ras inhibitors, such as a statin and farnesyl-transferase inhibitor, we surprisingly identified five protein synthesis inhibitors as positive regulators. Using commonly employed cycloheximide as a representative compound, we show that protein synthesis inhibition increased nanoclustering and effector recruitment specifically of active H-ras but not of K-ras. Consistent with these data, cycloheximide treatment activated both Erk and Akt kinases and specifically promoted H-rasG12V-induced, but not K-rasG12V-induced, PC12 cell differentiation. Intriguingly, cycloheximide increased the number of mammospheres, which are enriched for cancer stem cells. Depletion of H-ras in combination with cycloheximide significantly reduced mammosphere formation, suggesting an exquisite synthetic lethality. The potential of cycloheximide to promote tumor cell growth was also reflected in its ability to increase breast cancer cell tumors grown in ovo. These results illustrate the possibility of identifying Ras-isoform-specific modulators using nanocluster-directed screening. They also suggest an unexpected feedback from protein synthesis inhibition to Ras signaling, which might present a vulnerability in certain tumor cell types. PMID:26568031

  12. Identification of H7 as a novel peroxiredoxin I inhibitor to induce differentiation of leukemia cells

    PubMed Central

    Qin, Dongjun; Chen, Yingyi; Liu, Chuanxu; Xia, Li; Wang, Tongdan; Lei, Hu; Yu, Yun; Huang, Min; Tong, Yin; Xu, Hanzhang; Gao, Fenghou

    2016-01-01

    Identifying novel targets to enhance leukemia-cell differentiation is an urgent requirment. 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

  13. Effects of matrix metalloproteinase inhibitor on LPS-induced goblet cell metaplasia.

    PubMed

    Kim, Je Hyeong; Lee, Sung Yong; Bak, Sang Myeon; Suh, In Bum; Lee, Sang Yeub; Shin, Chol; Shim, Jae Jeong; In, Kwang Ho; Kang, Kyung Ho; Yoo, Se Hwa

    2004-07-01

    Bacterial infections of the lung are known to induce inflammatory responses, which lead to mucus hypersecretion. Moreover, mucin synthesis in the airways has been reported to be regulated by neutrophilic inflammation-induced epidermal growth factor receptor (EGFR) expression and its activation. Furthermore, matrix metalloproteinases (MMPs), especially MMP-9, have been reported to promote the transmigration of activated neutrophils. In this study, we investigated the associations between lipopolysaccharide (LPS)-induced goblet cell (GC) metaplasia and EGFR expression and the effects of MMP inhibitor (MMPI). Various concentrations of LPS were instilled into the tracheas of pathogen-free Sprague-Dawley rats, and airways were examined at different times after LPS instillation. To examine the role of MMP-9, we treated rats 3 days before LPS instillation and daily thereafter with MMPI. Neutrophilic infiltration, Alcian blue/periodic acid-Schiff (AB/PAS) staining, and immunohistochemical staining for MUC5AC, EGFR, and MMP-9 were performed. The instillation of LPS increased AB/PAS and MUC5AC staining in time- and dose-dependent manners, and treatment with MMPI significantly prevented GC metaplasia. The instillation of LPS into the trachea also induced neutrophilic infiltration and EGFR and MMP-9 expression in the airway epithelium, and MMPI was found to significantly prevent neutrophil recruitment, GC metaplasia, and EGFR and MMP-9 expression. This study demonstrates that the MMP-9 and EGFR cascades are associated with LPS-induced mucus hypersecretion. PMID:15020297

  14. Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats

    PubMed Central

    Lee, Eunjo; Song, Min-ji; Lee, Hae-Ahm; Kang, Seol-Hee; Kim, Mina; Yang, Eun Kyoung; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung

    2016-01-01

    CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats. PMID:27610034

  15. 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

  16. Icariside II, a novel phosphodiesterase-5 inhibitor, attenuates streptozotocin-induced cognitive deficits in rats.

    PubMed

    Yin, Caixia; Deng, Yuanyuan; Gao, Jianmei; Li, Xiaohui; Liu, Yuangui; Gong, Qihai

    2016-07-22

    Beta-amyloid (Aβ) deposition and neuroinflammation are involved in Alzheimer's disease (AD)-type neurodegeneration with cognitive deficits. Phosphodiesterase-5 (PDE5) inhibitors have recently been studied as a potential target for cognitive enhancement by reducing inflammatory responses and Aβ levels. The present study was designed to investigate the effects of icariside II (ICS II), a novel PDE5 inhibitor derived from the traditional Chinese herb Epimedium brevicornum, on cognitive deficits, Aβ levels and neuroinflammation induced by intracerebroventricular-streptozotocin (ICV-STZ) in rats. The results demonstrated that ICV-STZ exhibited cognitive deficits and neuronal morphological damage, along with Aβ increase and neuroinflammation in the rat hippocampus. ICS II improved cognitive deficits, attenuated neuronal death, and decreased the levels of Aβ1-40, Aβ1-42 and PDE5 in the hippocampus of STZ rats. Furthermore, administration of ICS II at the dose of 10mg/kg for 21days significantly suppressed the expression of beta-amyloid precursor protein (APP), beta-secretase1 (BACE1) and increased the expressions of neprilysin (NEP) together with inhibited interleukin-1β (IL-1β), tumor necrosis factor (TNF)-α, cyclooxygenase-2 (COX-2) and transforming growth factor-β1 (TGF-β1) levels. In addition, ICS II exerted a beneficial effect on inhibition of IκB-α degradation and NF-κB activation induced by STZ. Taken together, the present study demonstrated that ICS II was a potential therapeutic agent for AD treatment. PMID:27109920

  17. Histone deacetylase inhibitors induce growth arrest and differentiation in uveal melanoma

    PubMed Central

    Landreville, Solange; Agapova, Olga A.; Matatall, Katie A.; Kneass, Zachary T.; Onken, Michael D.; Lee, Ryan S.; Bowcock, Anne M.; Harbour, J. William

    2011-01-01

    Purpose Metastasis is responsible for the death of most cancer patients, yet few therapeutic agents are available which specifically target the molecular events that lead to metastasis. We recently showed that inactivating mutations in the tumor suppressor gene BAP1 are closely associated with loss of melanocytic differentiation in uveal melanoma and metastasis (UM). The purpose of this study was to identify therapeutic agents that reverse the phenotypic effects of BAP1 loss in UM. Experimental Design In silico screens were performed to identify therapeutic compounds predicted to differentiate UM cells using Gene Set Enrichment Analysis and Connectivity Map databases. Valproic acid, trichostatin A, LBH-589 and suberoylanilide hydroxamic acid were evaluated for their effects on UM cells using morphologic evaluation, MTS viability assays, BrdU incorporation, flow cytometry, clonogenic assays, gene expression profiling, histone acetylation and ubiquitination assays, and a murine xenograft tumorigenicity model. Results HDAC inhibitors induced morphologic differentiation, cell cycle exit, and a shift to a differentiated, melanocytic gene expression profile in cultured UM cells. Valproic acid inhibited the growth of UM tumors in vivo. Conclusions These findings suggest that HDAC inhibitors may have therapeutic potential for inducing differentiation and prolonged dormancy of micrometastatic disease in UM. PMID:22038994

  18. Histone Deacetylase Inhibitors: The Epigenetic Therapeutics That Repress Hypoxia-Inducible Factors

    PubMed Central

    Chen, Shuyang; Sang, Nianli

    2011-01-01

    Histone deacetylase inhibitors (HDACIs) have been actively explored as a new generation of chemotherapeutics for cancers, generally known as epigenetic therapeutics. Recent findings indicate that several types of HDACIs repress angiogenesis, a process essential for tumor metabolism and progression. Accumulating evidence supports that this repression is mediated by disrupting the function of hypoxia-inducible factors (HIF-1, HIF-2, and collectively, HIF), which are the master regulators of angiogenesis and cellular adaptation to hypoxia. Since HIF also regulate glucose metabolism, cell survival, microenvironment remodeling, and other alterations commonly required for tumor progression, they are considered as novel targets for cancer chemotherapy. Though the precise biochemical mechanism underlying the HDACI-triggered repression of HIF function remains unclear, potential cellular factors that may link the inhibition of deacetylase activity to the repression of HIF function have been proposed. Here we review published data that inhibitors of type I/II HDACs repress HIF function by either reducing functional HIF-1α levels, or repressing HIF-α transactivation activity. In addition, underlying mechanisms and potential proteins involved in the repression will be discussed. A thorough understanding of HDACI-induced repression of HIF function may facilitate the development of future therapies to either repress or promote angiogenesis for cancer or chronic ischemic disorders, respectively. PMID:21151670

  19. Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.

    PubMed

    Lee, Eunjo; Song, Min-Ji; Lee, Hae-Ahm; Kang, Seol-Hee; Kim, Mina; Yang, Eun Kyoung; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung; Kim, Inkyeom

    2016-09-01

    CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats. PMID:27610034

  20. Histone deacetylase inhibitors and aspirin interact synergistically to induce cell death in ovarian cancer cells.

    PubMed

    Sonnemann, Jürgen; Hüls, Isabel; Sigler, Michael; Palani, Chithra D; Hong, Le Thi Thu; Völker, Uwe; Kroemer, Heyo K; Beck, James F

    2008-07-01

    Histone deacetylase inhibitors (HDIs) as well as non-steroidal anti-inflammatory drugs including aspirin show promise as antineoplastic agents. The treatment with both HDIs and aspirin can result in hyperacetylation of proteins. In this study, we investigated whether HDIs and aspirin interacted in inducing anticancer activity and histone acetylation. We found that the HDIs, suberoylanilide hydroxamic acid and sodium butyrate, and aspirin cooperated to induce cell death in the ovarian cancer cell line, A2780. The effect was synergistic, as evidenced by CI-isobologram analysis. However, aspirin had no effect on histone acetylation, neither in the absence nor presence of HDIs. To gain insight into the mechanism underlying the synergistic action of HDIs and aspirin, we employed the deacetylated metabolite of aspirin, salicylic acid, and the cyclooxygenase-1- and -2-selective inhibitors, SC-560 and NS-398, respectively. We found that HDIs and salicylic acid interacted synergistically, albeit less efficiently than HDIs and aspirin, to induce cancer cell death, suggesting that the acetyl and the salicyl moiety contributed to the cooperative interaction of aspirin with HDIs. SC-560 and NS-398 had little effect both when applied alone or in conjunction with HDIs, indicating that the combinatorial effect of HDIs and aspirin was not the result of cyclo-oxygenase inhibition. In conclusion, our study demonstrates that HDIs and aspirin synergize to induce cancer cell death and, thus, provides a rationale for a more in-depth exploration into the potential of combining HDIs and aspirin as a strategy for anticancer therapy. PMID:18575740

  1. Bowman-Birk protease inhibitor from soybeans enhances cisplatin-induced cytotoxicity in human mesothelioma cells

    PubMed Central

    KASHIWAGI, KOREHITO; VIRGONA, NANTIGA; YAMADA, JIN; SATO, AYAMI; OTA, MASAKO; YAZAWA, TAKUYA; YANO, TOMOHIRO

    2011-01-01

    Malignant mesothelioma (MM) is an aggressive cancer with no effective treatment options. Enforced expression of the gap junction (GJ) component connexin 43 (Cx43) increases the sensitivity of MM cells to cisplatin. Bowman-Birk protease inhibitor (BBI) induces the restoration of Cx43 in several types of tumor cells. In this study, we examined the capability of BBI to enhance the cytotoxic effect of cisplatin in MM cells via the induction of Cx43. Human MM H28 cells were used. Cell viability was evaluated by a WST-1 assay and proteasomal activity was determined by fluorometric analysis. Protein and mRNA levels were determined by immunoblot analysis and real-time RT-PCR, respectively. GJ function mediated by Cx43 was evaluated using the scrape-loading method. BBI effectively inhibited H28 cell growth in a dose-dependent manner (200–400 μg/ml). In parallel with the growth inhibition, Cx43 levels (mRNA and protein) and GJ function were elevated by BBI treatment. Knockdown of BBI-induced Cx43 by an antisense nucleotide treatment almost cancelled the growth inhibition. BBI enhanced cisplatin-induced cytotoxicity in H28 cells, and down-regulation of Cx43 by the antisense nucleotide treatment abrogated the enhancing effect of BBI. The induction of Cx43 by BBI contributed to Src inactivation and subsequent induction of Bax. Furthermore, an Src inhibitor (SU6656) also enhanced cisplatin-induced cytotoxicity in H28 cells. These results suggest that BBI improves the cytotoxic efficacy of cisplatin in H28 cells via the inhibition of Src signaling. PMID:22977565

  2. 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. 55:1982–1989, 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

  3. Is peroxisome proliferation an obligatory precursor step in the carcinogenicity of di(2-ethylhexyl)phthalate (DEHP)?

    PubMed Central

    Melnick, R L

    2001-01-01

    Di(2-ethylhexyl)phthalate (DEHP), a peroxisome proliferator, has been listed by the International Agency for Research on Cancer (IARC) and by the National Toxicology Program as a possible or reasonably anticipated human carcinogen because it induces dose-related increases in liver tumors in both sexes of rats and mice. Recently, the suggestion has been advanced that DEHP should be considered unlikely to be a human carcinogen because it is claimed that the carcinogenic effects of this agent in rodents are due to peroxisome proliferation and that humans are nonresponsive to this process. An IARC working group recently downgraded DEHP to "not classifiable as to its carcinogenicity to humans" because they concluded that DEHP produces liver tumors in rats and mice by a mechanism involving peroxisome proliferation, which they considered to be not relevant to humans. The literature review presented in this commentary reveals that, although our knowledge of the mechanism of peroxisome proliferation has advanced greatly over the past 10 years, our understanding of the mechanism(s) of carcinogenicty of peroxisome proliferators remains incomplete. Most important is that published studies have not established peroxisome proliferation per se as an obligatory pathway in the carcinogenicity of DEHP. No epidemiologic studies have been reported on the potential carcinogenicity of DEHP, and cancer epidemiologic studies of hypolipidemic fibrate drugs (peroxisome proliferators) are inconclusive. Most of the pleiotropic effects of peroxisome proliferators are mediated by the peroxisome proliferator activated receptor (PPAR), a ligand-activated transcription factor that is expressed at lower levels in humans than in rats and mice. In spite of this species difference in PPAR expression, hypolipidemic fibrates have been shown to induce hypolipidemia in humans and to modulate gene expression (e.g., genes regulating lipid homeostasis) in human hepatocytes by PPAR activation. Thus, humans

  4. 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 β-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

  5. 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.

  6. 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

  7. Phosphodiesterase 5 inhibitors prevent 3,4-methylenedioxymethamphetamine-induced 5-HT deficits in the rat.

    PubMed

    Puerta, Elena; Hervias, Isabel; Goñi-Allo, Beatriz; Lasheras, Berta; Jordan, Joaquin; Aguirre, Norberto

    2009-02-01

    inhibitor. In conclusion, sildenafil protects against MDMA-induced long-term reduction of indoles by a mechanism involving increased production of cGMP and subsequent activation of PKG and mitochondrial ATP-sensitive K(+) channel opening. PMID:19187094

  8. The B-RafV600E inhibitor dabrafenib selectively inhibits RIP3 and alleviates acetaminophen-induced liver injury

    PubMed Central

    Li, J-X; Feng, J-M; Wang, Y; Li, X-H; Chen, X-X; Su, Y; Shen, Y-Y; Chen, Y; Xiong, B; Yang, C-H; Ding, J; Miao, Z-H

    2014-01-01

    Receptor-interacting protein (RIP)3 is a critical regulator of necroptosis and has been demonstrated to be associated with various diseases, suggesting that its inhibitors are promising in the clinic. However, there have been few RIP3 inhibitors reported as yet. B-RafV600E inhibitors are an important anticancer drug class for metastatic melanoma therapy. In this study, we found that 6 B-Raf inhibitors could inhibit RIP3 enzymatic activity in vitro. Among them, dabrafenib showed the most potent inhibition on RIP3, which was achieved by its ATP-competitive binding to the enzyme. Dabrafenib displayed highly selective inhibition on RIP3 over RIP1, RIP2 and RIP5. Moreover, only dabrafenib rescued cells from RIP3-mediated necroptosis induced by the necroptosis-induced combinations, that is, tumor necrosis factor (TNF)α, TNF-related apoptosis-inducing ligand or Fas ligand plus Smac mimetic and the caspase inhibitor z-VAD. Dabrafenib decreased the RIP3-mediated Ser358 phosphorylation of mixed lineage kinase domain-like protein (MLKL) and disrupted the interaction between RIP3 and MLKL. Notably, RIP3 inhibition of dabrafenib appeared to be independent of its B-Raf inhibition. Dabrafenib was further revealed to prevent acetaminophen-induced necrosis in normal human hepatocytes, which is considered to be mediated by RIP3. In acetaminophen-overdosed mouse models, dabrafenib was found to apparently ease the acetaminophen-caused liver damage. The results indicate that the anticancer B-RafV600E inhibitor dabrafenib is a RIP3 inhibitor, which could serve as a sharp tool for probing the RIP3 biology and as a potential preventive or therapeutic agent for RIP3-involved necroptosis-related diseases such as acetaminophen-induced liver damage. PMID:24901049

  9. Inhibition of polyamine oxidase prevented cyclin-dependent kinase inhibitor-induced apoptosis in HCT 116 colon carcinoma cells.

    PubMed

    Gürkan, Ajda Coker; Arisan, Elif Damla; Obakan, Pinar; Palavan-Ünsal, Narçin

    2013-12-01

    Roscovitine and purvalanol are novel cyclin-dependent kinase (CDK) inhibitors that prevent cell proliferation and induce apoptotic cell death in various cancer cell lines. Although a number of studies have demonstrated the potential apoptotic role of roscovitine, there is limited data about the therapeutic efficiency of purvalanol on cancer cells. The natural polyamines (PAs) putrescine, spermidine, and spermine have essential roles in the regulation of cell differentiation, growth, and proliferation, and increased levels of these compounds have been associated with cancer progression. Recently, depletion of intracellular PA levels because of modulation of PA catabolic enzymes was shown to be an indicator of the efficacy of chemotherapeutic agents. In this study, our aim was to investigate the potential role of PA catabolic enzymes in CDK inhibitor-induced apoptosis in HCT 116 colon carcinoma cells. Exposure of cells to roscovitine or purvalanol decreased cell viability in a dose- and time-dependent manner. The selected concentrations of roscovitine and purvalanol inhibited cell viability by 50 % compared with control cells and induced apoptosis by activating the mitochondria-mediated pathway in a caspase-dependent manner. However, the apoptotic effect of purvalanol was stronger than that of roscovitine in HCT 116 cells. In addition, we found that CDK inhibitors decreased PA levels and significantly upregulated expression of key PA catabolic enzymes such as polyamine oxidase (PAO) and spermine oxidase (SMO). MDL-72,527, a specific inhibitor of PAO and SMO, decreased apoptotic potential of CDK inhibitors on HCT 116 cells. Moreover, transient silencing of PAO was also reduced prevented CDK inhibitor-induced apoptosis in HCT 116 cells. We conclude that the PA catabolic pathway, especially PAO, is a critical target for understanding the molecular mechanism of CDK inhibitor-induced apoptosis. PMID:23892915

  10. 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&#...

  11. 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...

  12. 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...

  13. Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling.

    PubMed

    Rodrigues-Diez, Raquel; González-Guerrero, Cristian; Ocaña-Salceda, Carlos; Rodrigues-Diez, Raúl R; Egido, Jesús; Ortiz, Alberto; Ruiz-Ortega, Marta; Ramos, Adrián M

    2016-01-01

    The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the rate of allograft rejection, although their chronic use is marred by a range of side effects, among them vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4. Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4(-/-) mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the absence of calcineurin, although its expression was required for maximal effect through upregulation of TLR4 signaling. CNI-induced TLR4 activity increased O2(-)/ROS production and NF-κB-regulated synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data provide new insight into the mechanisms associated with CNI vascular inflammation. PMID:27295076

  14. Targeting ER stress-induced autophagy overcomes BRAF inhibitor resistance in melanoma.

    PubMed

    Ma, Xiao-Hong; Piao, Sheng-Fu; Dey, Souvik; McAfee, Quentin; Karakousis, Giorgos; Villanueva, Jessie; Hart, Lori S; Levi, Samuel; Hu, Janice; Zhang, Gao; Lazova, Rossitza; Klump, Vincent; Pawelek, John M; Xu, Xiaowei; Xu, Wei; Schuchter, Lynn M; Davies, Michael A; Herlyn, Meenhard; Winkler, Jeffrey; Koumenis, Constantinos; Amaravadi, Ravi K

    2014-03-01

    Melanomas that result from mutations in the gene encoding BRAF often become resistant to BRAF inhibition (BRAFi), with multiple mechanisms contributing to resistance. While therapy-induced autophagy promotes resistance to a number of therapies, especially those that target PI3K/mTOR signaling, its role as an adaptive resistance mechanism to BRAFi is not well characterized. Using tumor biopsies from BRAF(V600E) melanoma patients treated either with BRAFi or with combined BRAF and MEK inhibition, we found that BRAFi-resistant tumors had increased levels of autophagy compared with baseline. Patients with higher levels of therapy-induced autophagy had drastically lower response rates to BRAFi and a shorter duration of progression-free survival. In BRAF(V600E) melanoma cell lines, BRAFi or BRAF/MEK inhibition induced cytoprotective autophagy, and autophagy inhibition enhanced BRAFi-induced cell death. Shortly after BRAF inhibitor treatment in melanoma cell lines, mutant BRAF bound the ER stress gatekeeper GRP78, which rapidly expanded the ER. Disassociation of GRP78 from the PKR-like ER-kinase (PERK) promoted a PERK-dependent ER stress response that subsequently activated cytoprotective autophagy. Combined BRAF and autophagy inhibition promoted tumor regression in BRAFi-resistant xenografts. These data identify a molecular pathway for drug resistance connecting BRAFi, the ER stress response, and autophagy and provide a rationale for combination approaches targeting this resistance pathway. PMID:24569374

  15. Inter-α inhibitor protein and its associated glycosaminoglycans protect against histone-induced injury

    PubMed Central

    Chaaban, Hala; Keshari, Ravi S.; Silasi-Mansat, Robert; Popescu, Narcis I.; Mehta-D’Souza, Padmaja; Lim, Yow-Pin

    2015-01-01

    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-α 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

  16. Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling

    PubMed Central

    Rodrigues-Diez, Raquel; González-Guerrero, Cristian; Ocaña-Salceda, Carlos; Rodrigues-Diez, Raúl R.; Egido, Jesús; Ortiz, Alberto; Ruiz-Ortega, Marta; Ramos, Adrián M.

    2016-01-01

    The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the rate of allograft rejection, although their chronic use is marred by a range of side effects, among them vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4. Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4−/− mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the absence of calcineurin, although its expression was required for maximal effect through upregulation of TLR4 signaling. CNI-induced TLR4 activity increased O2−/ROS production and NF-κB-regulated synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data provide new insight into the mechanisms associated with CNI vascular inflammation. PMID:27295076

  17. The Na+/H+ exchange inhibitor HOE642 prevents stress-induced epithelial barrier dysfunction.

    PubMed

    Nowak, Peter; Blaheta, Roman; Schuller, Alina; Cinatl, Jindrich; Wimmer-Greinecker, Gerhard; Moritz, Anton; Scholz, Martin

    2004-08-01

    Recently, evidence has been obtained that the Na+/H+ exchange (NHE) inhibitor HOE642 may stabilize endothelial and epithelial barrier function in vivo. However, the underlying mechanisms are not known. Therefore, we studied the influence of HOE642 on the barrier function of the epithelial cell line CaCo2. The phorbolester phorbol 12-myristate 13-acetate (PMA) was used to induce hyperpermeability of the epithelial layer which was indirectly determined by measuring the transepithelial electrical resistance (TER). Confocal laser scan microscopy (LSM) served to analyze the intracellular localization of adherens and tight junction molecules. In five independent experiments we found that HOE642 increased TER in non-treated CaCo2 cells (control: 350 +/- 28 Omega/cm2; HOE642: 444 +/- 53 Omega/cm2) and prevented PMA-induced barrier dysfunction (PMA: 33 +/- 12 Omega/cm2; PMA plus HOE642: 496 +/- 47 Omega/cm2). LSM showed that HOE642 prevented the PMA-induced disassociation of the zonula adherens molecule beta-catenin from the cell membrane and the decreased expression of the zonula occludens molecule ZO-1. From our data we conclude that HOE642 may prevent stress-induced epithelial dysfunction by stabilization of cell membrane-associated junction molecules. PMID:15254761

  18. Attenuating Aβ1-42-induced toxicity by a novel acetylcholinesterase inhibitor.

    PubMed

    Mishra, N; Sasmal, D; Singh, K K

    2013-10-10

    We explored the attenuating effects of NP-9 on β-amyloid (Aβ) aggregation and amyloid-induced toxicity. NP-9 is a recently reported monoamine oxidase B (MAO-B), and acetylcholinesterase (AChE) inhibitor. In the present study, we found that NP-9 inhibited AChE activity in a dose-dependent manner with a maximal inhibition dose of 8 mg/kg, i.p. It inhibited Aβ aggregation, observed through thioflavin-T assay (IC50=60 μM) and scanning electron microscopy (S.E.M.) (no fibril formation). NP-9 has shown marked protection against scopolamine and Aβ1-42-induced memory impairments. It also minimized neuronal loss and amyloid plaque deposition in the brains of Aβ1-42-induced mice model. Therefore, NP-9 could be a promising lead molecule for AD, with effects against MAO-B, AChE, Aβ aggregation, and Aβ1-42 induced toxicity. PMID:23872389

  19. Deciphering the molecular and biologic processes that mediate histone deacetylase inhibitor-induced thrombocytopenia.

    PubMed

    Bishton, Mark J; Harrison, Simon J; Martin, Benjamin P; McLaughlin, Nicole; James, Chloé; Josefsson, Emma C; Henley, Katya J; Kile, Benjamin T; Prince, H Miles; Johnstone, Ricky W

    2011-03-31

    Histone deacetylase inhibitor (HDACI)-induced thrombocytopenia (TCP) is a major dose-limiting toxicity of this new class of drugs. Using preclinical models to study the molecular and biologic events that underpin this effect of HDACI, we found that C57BL/6 mice treated with both the HDAC1/2-selective HDACI romidepsin and the pan-HDACI panobinostat developed significant TCP. HDACI-induced TCP was not due to myelosuppression or reduced platelet lifespan, but to decreased platelet release from megakaryocytes. Cultured primary murine megakaryocytes showed reductions in proplatelet extensions after HDACI exposure and a dose-dependent increase in the phosphorylation of myosin light chain 2 (MLC2). Phosphorylation of MLC to phospho-MLC (pMLC) and subsequent proplatelet formation in megakaryocytes is regulated by the Rho-GTPase proteins Rac1, CDC42, and RhoA. Primary mouse megakaryocytes and the human megakaryoblastic cell line Meg-01 showed reductions in Rac1, CDC42, and RhoA protein levels after treatment with HDACIs. We were able to overcome HDACI-induced TCP by administering the mouse-specific thrombopoietin (TPO) mimetic AMP-4, which improved platelet numbers to levels similar to untreated controls. Our report provides the first detailed account of the molecular and biologic processes involved in HDACI-mediated TCP. Moreover, our preclinical studies provide evidence that dose-limiting TCP induced by HDACIs may be circumvented using a TPO mimetic. PMID:21292776

  20. 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 α7 nicotinic receptor (α7-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 α7-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

  1. Isoflurane-induced spatial memory impairment in mice is prevented by the acetylcholinesterase inhibitor donepezil.

    PubMed

    Su, Diansan; Zhao, Yanxing; 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 α7 nicotinic receptor (α7-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 α7-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

  2. B-Raf inhibitors induce epithelial differentiation in BRAF-mutant colorectal cancer cells.

    PubMed

    Herr, Ricarda; Köhler, Martin; Andrlová, Hana; Weinberg, Florian; Möller, 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

  3. Charcot-Marie-Tooth disease-associated mutants of GDAP1 dissociate its roles in peroxisomal and mitochondrial fission

    PubMed Central

    Huber, Nina; Guimaraes, Sofia; Schrader, Michael; Suter, Ueli; Niemann, Axel

    2013-01-01

    Mitochondria and peroxisomes can be fragmented by the process of fission. The fission machineries of both organelles share a set of proteins. GDAP1 is a tail-anchored protein of mitochondria and induces mitochondrial fragmentation. Mutations in GDAP1 lead to Charcot-Marie-Tooth disease (CMT), an inherited peripheral neuropathy, and affect mitochondrial dynamics. Here, we show that GDAP1 is also targeted to peroxisomes mediated by the import receptor Pex19. Knockdown of GDAP1 leads to peroxisomal elongation that can be rescued by re-expressing GDAP1 and by missense mutated forms found in CMT patients. GDAP1-induced peroxisomal fission is dependent on the integrity of its hydrophobic domain 1, and on Drp1 and Mff, as is mitochondrial fission. Thus, GDAP1 regulates mitochondrial and peroxisomal fission by a similar mechanism. However, our results reveal also a more critical role of the amino-terminal GDAP1 domains, carrying most CMT-causing mutations, in the regulation of mitochondrial compared to peroxisomal fission. PMID:23628762

  4. Regulation of apoptosis by peroxisome proliferators.

    PubMed

    Roberts, Ruth A; Michel, Cecile; Coyle, Beth; Freathy, Caroline; Cain, Kelvin; Boitier, Eric

    2004-04-01

    Peroxisome proliferators (PPs) constitute a large and chemically diverse family of non-genotoxic rodent hepatocarcinogens that activate the PP-activated receptor alpha (PPARalpha). In order to investigate the hypothesis that PPs elicit their carcinogenic effects through the suppression of apoptosis, we established an in vitro assay for apoptosis using both primary rat hepatocytes and the FaO rat hepatoma cell line. Apoptosis was induced by transforming growth factor beta1 (TGFbeta1), the physiological negative regulator of liver growth. In this system, PPs could suppress both spontaneous and TGFbeta1-induced apoptosis. In order to understand the mechanisms of this regulation of apoptosis, we conducted microarray analysis followed by pathway-specific gene clustering in TGFbeta1-treated cells. After treatment, 76 genes were up-regulated and 185 were down-regulated more than 1.5-fold. Cluster analysis of up-regulated genes revealed three clusters, A-C. Cluster A (4h) was associated with 12% apoptosis and consisted of genes mainly of the cytoskeleton and extracellular matrix such as troponin and the proteoglycan SDC4. In cluster B (8h; 25% apoptosis), there were many pro- and anti-apoptotic genes such as XIAP, BAK1 and BAD, whereas at 16h (40% apoptosis) the regulated genes were mainly those of the cellular stress pathways such as the genes implicated in the activation of the transcription factor NFkappab. Genes found down-regulated in response to TGFbeta1 were mainly those associated with oxidative stress and several genes implicated in glutathione production and maintenance. Thus, TGFbeta1 may induce apoptosis via a down regulation of oxidant defence leading to the generation of reactive oxygen species. The ability of PPs to impact on these apoptosis pathways remains to be determined. To approach this question, we have developed a technique using laser capture microdissection of livers treated with the PP, clofibric acid coupled with gene expression array analysis

  5. Microinjection of histone deacetylase inhibitor into the ventrolateral orbital cortex potentiates morphine induced behavioral sensitization.

    PubMed

    Wei, Lai; Zhu, Yuan-Mei; Zhang, Yu-Xiang; Liang, Feng; Barry, Devin M; Gao, Hong-Yu; Li, Tao; Huo, Fu-Quan; Yan, Chun-Xia

    2016-09-01

    Accumulating evidence indicates that epigenetic regulation, such as changes in histone modification in reward-related brain regions, contributes to the memory formation of addiction to opiates and psychostimulants. Our recent results suggested that the ventrolateral orbital cortex (VLO) is involved in the memories of stress and drug addiction. Since addiction and stress memories share some common pathways, the present study was designed to investigate the role of histone deacetylase (HDAC) activity in the VLO during morphine induced-behavioral sensitization. Rats received a single exposure to morphine for establishing the behavioral sensitization model. The effect of HDAC activity in the VLO in morphine induced-behavioral sensitization was examined by microinjection of HDAC inhibitor Trichostatin A (TSA). Furthermore, the protein expression levels of extracellular signal-regulated kinase (ERK) and phosphorylated ERK (p-ERK), histone H3 lysine 9 acetylation (aceH3K9) and brain-derived neurotrophic factor (BDNF) in the VLO in morphine-induced behavioral sensitization were examined. The results showed that the bilateral VLO lesions suppressed the expression phase, but not the developmental phase of morphine-induced behavioral sensitization. Microinjection of TSA into the VLO significantly increased both the development and expression phases. Moreover, the protein levels of p-ERK, aceH3K9 and BDNF except ERK in the VLO were significantly upregulated in morphine-treated rats in the expression phase. These effects were further strengthened by intra-VLO injection of TSA. Our findings suggest that HDAC activity in the VLO could potentiate morphine-induced behavioral sensitization. The upregulated expression of p-ERK, aceH3K9 and BDNF in the VLO might be the underlying mechanism of histone acetylation enhancing the morphine-induced behavioral sensitization. PMID:27312092

  6. 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.

  7. Immune checkpoint inhibitors enhance cytotoxicity of cytokine-induced killer cells against human myeloid leukaemic blasts.

    PubMed

    Poh, Su Li; Linn, Yeh Ching

    2016-05-01

    We studied whether blockade of inhibitory receptors on cytokine-induced killer (CIK) cells by immune checkpoint inhibitors could increase its anti-tumour potency against haematological malignancies. CIK cultures were generated from seven normal donors and nine patients with acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL) or multiple myeloma (MM). The inhibitory receptors B and T lymphocyte attenuator, CD200 receptor, lymphocyte activation gene-3 (LAG-3) and T cell immunoglobulin and mucin-domain-containing-3 (TIM-3) were present at variable percentages in most CIK cultures, while cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed death-1 (PD-1) and killer cell immunoglobulin-like receptors (KIR2DL1/2/3) were expressed at low level in most cultures. Without blockade, myeloid leukaemia cells were susceptible to autologous and allogeneic CIK-mediated cytotoxicity. Blockade of KIR, LAG-3, PD-1 and TIM-3 but not CTLA-4 resulted in remarkable increase in killing against these targets, even in those with poor baseline cytotoxicity. ALL and MM targets were resistant to CIK-mediated cytotoxicity, and blockade of receptors did not increase cytotoxicity to a meaningful extent. Combination of inhibitors against two receptors did not further increase cytotoxicity. Interestingly, potentiation of CIK killing by blocking antibodies was not predicted by expression of receptors on CIK and their respective ligands on the targets. Compared to un-activated T and NK cells, blockade potentiated the cytotoxicity of CIK cells to a greater degree and at a lower E:T ratio, but without significant increase in cytotoxicity against normal white cell. Our findings provide the basis for clinical trial combining autologous CIK cells with checkpoint inhibitors for patients with AML. PMID:26961084

  8. Amelioration of Acute Kidney Injury in Lipopolysaccharide-Induced Systemic Inflammatory Response Syndrome by an Aldose Reductase Inhibitor, Fidarestat

    PubMed Central

    Takahashi, Kazunori; Mizukami, Hiroki; Kamata, Kosuke; Inaba, Wataru; Kato, Noriaki; Hibi, Chihiro; Yagihashi, Soroku

    2012-01-01

    Background Systemic inflammatory response syndrome is a fatal disease because of multiple organ failure. Acute kidney injury is a serious complication of systemic inflammatory response syndrome and its genesis is still unclear posing a difficulty for an effective treatment. Aldose reductase (AR) inhibitor is recently found to suppress lipopolysaccharide (LPS)-induced cardiac failure and its lethality. We studied the effects of AR inhibitor on LPS-induced acute kidney injury and its mechanism. Methods Mice were injected with LPS and the effects of AR inhibitor (Fidarestat 32 mg/kg) before or after LPS injection were examined for the mortality, severity of renal failure and kidney pathology. Serum concentrations of cytokines (interleukin-1β, interleukin-6, monocyte chemotactic protein-1 and tumor necrosis factor-α) and their mRNA expressions in the lung, liver, spleen and kidney were measured. We also evaluated polyol metabolites in the kidney. Results Mortality rate within 72 hours was significantly less in LPS-injected mice treated with AR inhibitor both before (29%) and after LPS injection (40%) than untreated mice (90%). LPS-injected mice showed marked increases in blood urea nitrogen, creatinine and cytokines, and AR inhibitor treatment suppressed the changes. LPS-induced acute kidney injury was associated with vacuolar degeneration and apoptosis of renal tubular cells as well as infiltration of neutrophils and macrophages. With improvement of such pathological findings, AR inhibitor treatment suppressed the elevation of cytokine mRNA levels in multiple organs and renal sorbitol accumulation. Conclusion AR inhibitor treatment ameliorated LPS-induced acute kidney injury, resulting in the lowered mortality. PMID:22253906

  9. Hesperetin, a Selective Phosphodiesterase 4 Inhibitor, Effectively Suppresses Ovalbumin-Induced Airway Hyperresponsiveness without Influencing Xylazine/Ketamine-Induced Anesthesia

    PubMed Central

    Shih, Chung-Hung; Lin, Ling-Hung; Hsu, Hsin-Te; Wang, Kuo-Hsien; Lai, Chi-Yin; Chen, Chien-Ming; Ko, Wun-Chang

    2012-01-01

    Hesperetin, a selective phosphodiesterase (PDE)4 inhibitor, is present in the traditional Chinese medicine, “Chen Pi.” Therefore, we were interested in investigating its effects on ovalbumin- (OVA-) induced airway hyperresponsiveness, and clarifying its rationale for ameliorating asthma and chronic obstructive pulmonary disease (COPD). Hesperetin was revealed to have a therapeutic (PDE4H/PDE4L) ratio of >11. Hesperetin (10 ~ 30 μmol/kg, intraperitoneally (i.p.)) dose-dependently and significantly attenuated the airway hyperresponsiveness induced by methacholine. It also significantly suppressed the increases in total inflammatory cells, macrophages, lymphocytes, neutrophils, and eosinophils, and levels of cytokines, including interleukin (IL)-2, IL-4, IL-5, interferon-γ, and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF). It dose-dependently and significantly suppressed total and OVA-specific immunoglobulin E levels in the BALF and serum. However, hesperetin did not influence xylazine/ketamine-induced anesthesia, suggesting that hesperetin has few or no emetic effects. In conclusion, the rationales for ameliorating allergic asthma and COPD by hesperetin are anti-inflammation, immunoregulation, and bronchodilation. PMID:22454667

  10. Integrated Analysis of Drug-Induced Gene Expression Profiles Predicts Novel hERG Inhibitors

    PubMed Central

    Babcock, Joseph J.; Du, Fang; Xu, Kaiping; Wheelan, Sarah J.; Li, Min

    2013-01-01

    Growing evidence suggests that drugs interact with diverse molecular targets mediating both therapeutic and toxic effects. Prediction of these complex interactions from chemical structures alone remains challenging, as compounds with different structures may possess similar toxicity profiles. In contrast, predictions based on systems-level measurements of drug effect may reveal pharmacologic similarities not evident from structure or known therapeutic indications. Here we utilized drug-induced transcriptional responses in the Connectivity Map (CMap) to discover such similarities among diverse antagonists of the human ether-à-go-go related (hERG) potassium channel, a common target of promiscuous inhibition by small molecules. Analysis of transcriptional profiles generated in three independent cell lines revealed clusters enriched for hERG inhibitors annotated using a database of experimental measurements (hERGcentral) and clinical indications. As a validation, we experimentally identified novel hERG inhibitors among the unannotated drugs in these enriched clusters, suggesting transcriptional responses may serve as predictive surrogates of cardiotoxicity complementing existing functional assays. PMID:23936032

  11. [Vasoactive prostanoids and inhibitors of blood coagulation in pregnancy-induced hypertension].

    PubMed

    Peterseim, H; Kemkes-Matthes, B

    1994-01-01

    The aim of the present study was to investigate the occurrence of changes in the plasma levels of vasoactive prostanoids and inhibitors of blood coagulation in normal pregnancy and in cases of pregnancy induced hypertension. Levels of the coagulation inhibitors antithrombin III, protein C, Protein S as well as the prostaglandin metabolites thromboxane B2 and 6-oxo-prostaglandin F1 alpha were measured between 13 and 37 weeks gestation in 36 primigravidae. In 8 of the examined patients persistently raised blood pressure values of 140/90 and above were measured after 20 weeks of gestation. Our results indicated that an imbalance of vasoactive prostanoids may precede the appearance of clinical symptoms of PIH. The determination of coagulation factors before blood pressure is elevated has no predictive value regarding the later development of PIH. The reduced levels of protein C associated with our PIH group are considered to be the result of an activated coagulation followed by consumption of clotting factors. Reduced measured levels of protein S in normotensive as well as hypertensive pregnancies offer an explanation for the increased risk of thromboembolic disease. This increased susceptibility to thromboembolic disorders is further enhanced by the altered balance between the platelet aggregator and vasoconstrictor thromboxane A2 and its antagonist prostacyclin. PMID:8048287

  12. Chemically Accessible Hsp90 Inhibitor That Does Not Induce a Heat Shock Response

    PubMed Central

    2014-01-01

    Recent cancer therapies have focused on targeting biology networks through a single regulatory protein. Heat shock protein 90 (hsp90) is an ideal oncogenic target as it regulates over 400 client proteins and cochaperones. However, clinical inhibitors of hsp90 have had limited success; the primary reason being that they induce a heat shock response. We describe the synthesis and biological evaluation of a new hsp90 inhibitor, SM253. The previous generation on which SM253 is based (SM145) has poor overall synthetic yields, low solubility, and micromolar cytotoxicity. By comparison SM253 has relatively high overall yields, good aqueous solubility, and is more cytotoxic than its parent compound. Verification that hsp90 is SM253’s target was accomplished using pull-down and protein folding assays. SM253 is superior to both SM145 and the clinical candidate 17-AAG as it decreases proteins related to the heat shock response by 2-fold, versus a 2–4-fold increase observed when cells are treated with 17-AAG. PMID:25050163

  13. 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 β-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 β-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

  14. Peroxisome dynamics during development of the fungus Podospora anserina.

    PubMed

    Takano-Rojas, Harumi; Zickler, Denise; Peraza-Reyes, Leonardo

    2016-01-01

    Peroxisomes are versatile and dynamic organelles that are required for the development of diverse eukaryotic organisms. We demonstrated previously that in the fungus Podospora anserina different peroxisomal functions are required at distinct stages of sexual development, including the initiation and progression of meiocyte (ascus) development and the differentiation and germination of sexual spores (ascospores). Peroxisome assembly during these processes relies on the differential activity of the protein machinery that drives the import of proteins into the organelle, indicating a complex developmental regulation of peroxisome formation and activity. Here we demonstrate that peroxisome dynamics is also highly regulated during development. We show that peroxisomes in P. anserina are highly dynamic and respond to metabolic and environmental cues by undergoing changes in size, morphology and number. In addition, peroxisomes of vegetative and sexual cell types are structurally different. During sexual development peroxisome number increases at two stages: at early ascus differentiation and during ascospore formation. These processes are accompanied by changes in peroxisome structure and distribution, which include a cell-polarized concentration of peroxisomes at the beginning of ascus development, as well as a morphological transition from predominantly spherical to elongated shapes at the end of the first meiotic division. Further, the mostly tubular peroxisomes present from second meiotic division to early ascospore formation again become rounded during ascospore differentiation. Ultimately the number of peroxisomes dramatically decreases upon ascospore maturation. Our results reveal a precise regulation of peroxisome dynamics during sexual development and suggest that peroxisome constitution and function during development is defined by the coordinated regulation of the proteins that control peroxisome assembly and dynamics. PMID:26908647

  15. Can Exercise Ameliorate Aromatase Inhibitor-Induced Cognitive Decline in Breast Cancer Patients?

    PubMed

    Li, Cuicui; Zhou, Chenglin; Li, Rena

    2016-08-01

    Aromatase inhibitors (AIs) have been commonly used as an effective adjuvant therapy in treatment of breast cancer, especially for menopausal women with estrogen receptor-positive breast cancer. Due to the nature of aromatase, the key enzyme for endogenous estrogen synthesis, inhibitory of aromatase-induced side effects, such as cognitive impairment has been reported in both human and animal studies. While extensive evidence suggested that physical exercises can improve learning and memory activity and even prevent age-related cognitive decline, basic research revealed some common pathways between exercise and estrogen signaling that affected cognitive function. This review draws on clinical and basic studies to assess the potential impact of exercise in cognitive function from women treated with AIs for breast cancer and explore the potential mechanism and effects of exercise on estrogen-related cognition. PMID:26223800

  16. 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

  17. MK2 inhibitor reduces alkali burn-induced inflammation in rat cornea

    PubMed Central

    Chen, Yanfeng; Yang, Wenzhao; Zhang, Xiaobo; Yang, Shu; Peng, Gao; Wu, Ting; Zhou, Yueping; Huang, Caihong; Reinach, Peter S.; Li, Wei; Liu, Zuguo

    2016-01-01

    MK2 activation by p38 MAPK selectively induces inflammation in various diseases. We determined if a MK2 inhibitor (MK2i), improves cornea wound healing by inhibiting inflammation caused by burning rat corneas with alkali. Our study, for the first time, demonstrated that MK2i inhibited alkali burn-induced MK2 activation as well as rises in inflammation based on: a) blunting rises in inflammatory index, inflammatory cell infiltration, ED1+ macrophage and PMN+ neutrophil infiltration; b) suppressing IL-6 and IL-1β gene expression along with those of macrophage inflammatory protein-1α (MIP-1α), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1); c) reducing angiogenic gene expression levels and neovascularization (NV) whereas anti-angiogenic PEDF levels increased. In addition, this study found that MK2i did not affect human corneal epithelial cell (HCEC) proliferation and migration and had no detectable side effects on ocular surface integrity. Taken together, MK2i selectively inhibited alkali burn-induced corneal inflammation by blocking MK2 activation, these effects have clinical relevance in the treatment of inflammation related ocular surface diseases. PMID:27329698

  18. FK506, a calcineurin inhibitor, prevents cadmium-induced testicular toxicity in mice.

    PubMed

    Martin, Lisa Joy; Chen, Haiyan; Liao, Xiaoyan; Allayee, Hooman; Shih, Diana Mouhan; Lee, Grace Sangeun; Hovland, David Norman; Robbins, Wendie Anne; Carnes, Kay; Hess, Rex Allen; Lusis, Aldons Jake; Collins, Michael David

    2007-12-01

    Cadmium, a ubiquitous environmental contaminant, damages several major organs in humans and other mammals. The molecular mechanisms for damage are not known. At high doses (5 mg/kg cadmium chloride or higher), testicular damage in mice, rats, and other rodents includes interstitial edema, hemorrhage, and changes in the seminiferous tubules affecting spermatogenesis. Necrosis is evident by 48 h. The goal of this study was to fine map and identify the cdm gene, a gene that when mutated prevents cadmium-induced testicular toxicity in mouse strains with a mutation in this gene. A serine-threonine phosphatase, calcineurin (CN), subunit A, alpha isoform (Ppp3ca), was one of the seven candidates in the cdm region that was narrowed from 5.6 to 2.0 Mb on mouse chromosome 3. An inhibitor of CN, the immunosuppressant, FK506, prevented cadmium-induced testicular damage in five pathological categories, including vascular endothelial and seminiferous epithelial endpoints. Inductively coupled plasma-mass spectrometry revealed that FK506 protected without lowering the amount of cadmium in the testes. Ppp3ca(-/-) mice were investigated but were found to exhibit endogenous testicular abnormalities, making them an inappropriate model for determining whether the inactivation of the Ppp3ca gene would afford protection from cadmium-induced testicular toxicity. The protection afforded by FK506, found by the current study, indicated that CN is likely to be important in the mechanism of cadmium toxicity in the testis and possibly other organs. PMID:17785681

  19. A Receptor Tyrosine Kinase Inhibitor, Dovitinib (TKI-258), Enhances BMP-2-Induced Osteoblast Differentiation In Vitro.

    PubMed

    Lee, Yura; Bae, Kyoung Jun; Chon, Hae Jung; Kim, Seong Hwan; Kim, Soon Ae; Kim, Jiyeon

    2016-05-31

    Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders. PMID:27025387

  20. Effects of a Soluble Epoxide Hydrolase Inhibitor on Lipopolysaccharide-Induced Acute Lung Injury in Mice

    PubMed Central

    Yang, Liu-Qing; Ma, Yong-Bo

    2016-01-01

    Objectives Inflammation plays a key role in the pathogenesis of acute lung injury (ALI). Soluble epoxide hydrolase (sEH) is suggested as a vital pharmacologic target for inflammation. In this study, we determined whether a sEH inhibitor, AUDA, exerts lung protection in lipopolysaccharide (LPS)-induced ALI in mice. Methods Male BALB/c mice were randomized to receive AUDA or vehicle intraperitoneal injection 4 h after LPS or phosphate buffered saline (PBS) intratracheal instillation. Samples were harvested 24 h post LPS or PBS administration. Results AUDA administration decreased the pulmonary levels of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-α. Improvement of oxygenation and lung edema were observed in AUDA treated group. AUDA significantly inhibited sEH activity, and elevated epoxyeicosatrienoic acids (EETs) levels in lung tissues. Moreover, LPS induced the activation of nuclear factor (NF)-κB was markedly dampened in AUDA treated group. Conclusion Administration of AUDA after the onset of LPS-induced ALI increased pulmonary levels of EETs, and ameliorated lung injury. sEH is a potential pharmacologic target for ALI. PMID:27490848

  1. A Receptor Tyrosine Kinase Inhibitor, Dovitinib (TKI-258), Enhances BMP-2-Induced Osteoblast Differentiation In Vitro

    PubMed Central

    Lee, Yura; Bae, Kyoung Jun; Chon, Hae Jung; Kim, Seong Hwan; Kim, Soon Ae; Kim, Jiyeon

    2016-01-01

    Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders. PMID:27025387

  2. Peroxisomal beta-oxidation defect with detectable peroxisomes: a case with neonatal onset and progressive course.

    PubMed

    Barth, P G; Wanders, R J; Schutgens, R B; Bleeker-Wagemakers, E M; van Heemstra, D

    1990-07-01

    A progressive demyelinating cerebral disorder is described in a normally-appearing female infant with neonatal seizures, progressive psychomotor deterioration, deafness, retinopathy, peripheral neuropathy and loss of myelin observed on magnetic resonance imaging (MRI) scanning. MRI also showed the absence of macroscopic neocortical dysplasia which is usually found in Zellweger syndrome (ZS). Adrenal cortical function was normal. The patient died at the age of 37 months. Extensive biochemical investigations of peroxisomal functions in the patient revealed an impairment of peroxisomal beta-oxidation resulting in elevated levels of very long (greater than C22) chain fatty acids in plasma and fibroblasts. Moreover, elevated plasma levels of intermediates of bile acid biosynthesis such as tri- and dihydroxycholestanoic acid were found. Other peroxisomal functions were normal. Immunoblotting of the peroxisomal beta-oxidation enzyme proteins in liver from the patient revealed normal responses with antisera against acyl-CoA oxidase, bifunctional protein and thiolase respectively. From these data we conclude that the patient had a deficiency of a single peroxisomal beta-oxidation enzyme at the level of either the bifunctional protein or peroxisomal thiolase with retained immunoreactivity against these enzymes. PMID:2209666

  3. 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.

  4. 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.

  5. Renoprotective effect of the xanthine oxidoreductase inhibitor topiroxostat on adenine-induced renal injury.

    PubMed

    Kamijo-Ikemori, Atsuko; Sugaya, Takeshi; Hibi, Chihiro; Nakamura, Takashi; Murase, Takayo; Oikawa, Tsuyoshi; Hoshino, Seiko; Hisamichi, Mikako; Hirata, Kazuaki; Kimura, Kenjiro; Shibagaki, Yugo

    2016-06-01

    The aim of the present study was to reveal the effect of a xanthine oxidoreductase (XOR) inhibitor, topiroxostat (Top), compared with another inhibitor, febuxostat (Feb), in an adenine-induced renal injury model. We used human liver-type fatty acid-binding protein (L-FABP) chromosomal transgenic mice, and urinary L-FABP, a biomarker of tubulointerstitial damage, was used to evaluate tubulointerstitial damage. Male transgenic mice (n = 24) were fed a 0.2% (wt/wt) adenine-containing diet. Two weeks after the start of this diet, renal dysfunction was confirmed, and the mice were divided into the following four groups: the adenine group was given only the diet containing adenine, and the Feb, high-dose Top (Top-H), and low-dose Top (Top-L) groups were given diets containing Feb (3 mg/kg), Top-H (3 mg/kg), and Top-L (1 mg/kg) in addition to adenine for another 2 wk. After withdrawal of the adenine diet, each medication was continued for 2 wk. Serum creatinine levels, the degree of macrophage infiltration, tubulointerstitial damage, renal fibrosis, urinary 15-F2t-isoprostane levels, and renal XOR activity were significantly attenuated in the kidneys of the Feb, Top-L, and Top-H groups compared with the adenine group. Serum creatinine levels in the Top-L and Top-H groups as well as renal XOR in the Top-H group were significantly lower than those in the Feb group. Urinary excretion of L-FABP in both the Top-H and Top-L groups was significantly lower than in the adenine and Feb groups. In conclusion, Top attenuated renal damage in an adenine-induced renal injury model. PMID:27029427

  6. 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.

  7. The kinesin Eg5 inhibitor K858 induces apoptosis but also survivin-related chemoresistance in breast cancer cells.

    PubMed

    De Iuliis, Francesca; Taglieri, Ludovica; Salerno, Gerardo; Giuffrida, Anna; Milana, Bernardina; Giantulli, Sabrina; Carradori, Simone; Silvestri, Ida; Scarpa, Susanna

    2016-08-01

    Inhibitors of kinesin spindle protein Eg5 are characterized by pronounced antitumor activity. Our group has recently synthesized and screened a library of 1,3,4-thiadiazoline analogues with the pharmacophoric structure of K858, an Eg5 inhibitor. We herein report the effects of K858 on four different breast cancer cell lines: MCF7 (luminal A), BT474 (luminal B), SKBR3 (HER2 like) and MDA-MB231 (basal like). We demonstrated that K858 displayed anti-proliferative activity on every analyzed breast cancer cell line by inducing apoptosis. However, at the same time, we showed that K858 up-regulated survivin, an anti-apoptotic molecule. We then performed a negative regulation of survivin expression, with the utilization of wortmannin, an AKT inhibitor, and obtained a significant increase of K858-dependent apoptosis. These data demonstrate that K858 is a potent inhibitor of replication and induces apoptosis in breast tumor cells, independently from the tumor phenotype. This anti-proliferative response of tumor cells to K858 can be limited by the contemporaneous over-expression of survivin; consequently, the reduction of survivin levels, obtained with AKT inhibitors, can sensitize tumor cells to K858-induced apoptosis. PMID:26994617

  8. In vitro effects of cysteine protease inhibitors on Trichomonas foetus-induced cytopathic changes in porcine intestinal epithelial cells.

    PubMed

    Tolbert, M Katherine; Brand, Mabre D; Gould, Emily N

    2016-08-01

    OBJECTIVE To investigate the effects of specific cysteine protease (CP) inhibitors on cytopathic changes to porcine intestinal epithelial cells induced by Tritrichomonas foetus isolated from naturally infected cats. SAMPLE T foetus isolates from 4 naturally infected cats and nontransformed porcine intestinal epithelial cells. PROCEDURES T foetus isolates were treated with or without 0.1 to 1.0mM of the CP inhibitors antipain, cystatin, leupeptin, and chymostatin and the vinyl sulfone inhibitors WRR-483 and K11777. In-gel gelatin zymography was performed to evaluate the effects of these inhibitors on CP activity of T foetus isolates. Each treated or untreated isolate was also cocultured with monolayers of porcine intestinal epithelial cells for 24 hours, and cytopathic effects of T foetus were evaluated by light microscopy and crystal violet spectrophotometry. RESULTS Results of in-gel gelatin zymography suggested an ability of WRR-483, K11777, and cystatin to target specific zones of CP activity of the T foetus isolates. These inhibitors had no effect on T foetus growth, and the cytopathic changes to the intestinal epithelium induced by all 4 T foetus isolates were significantly inhibited. CONCLUSIONS AND CLINICAL RELEVANCE This study revealed that certain protease inhibitors were capable of inhibiting regions of CP activity (which has been suggested to cause intestinal cell damage in cats) in T foetus organisms and of ameliorating T foetus-induced cytopathic changes to porcine intestinal epithelium in vitro. Although additional research is needed, these inhibitors might be useful in the treatment of cats with trichomonosis. PMID:27463553

  9. Silencing of the polyamine catabolic key enzyme SSAT prevents CDK inhibitor-induced apoptosis in Caco-2 colon cancer cells.

    PubMed

    Çoker, A; Arısan, E D; Palavan-Ünsal, N

    2012-04-01

    Roscovitine and purvalanol are purine derivative cyclin-dependent kinase (CDK) inhibitors that induce apoptosis in various types of cancer cells. However, their impact on the apoptotic cell death mechanism requires further elucidation. Natural polyamines putrescine, spermidine and spermine play essential roles in the regulation of cell growth and proliferation. Increased levels of polyamines in cells are considered to be involved in cancer progression. Intracellular polyamine levels are under the control of several catabolic enzymes, such as spermidine/spermine-N-acetyl transferase (SSAT), acetylpolyamine oxidase (APAO) and spermine oxidase (SMO), which could be altered by several therapeutic drugs. However, the possible role of polyamines in drug-induced apoptosis has yet to be clarified. In the present study, our aim was to determine the modulation of the polyamine catabolic pathway related to CDK inhibitor-induced apoptosis in Caco-2 cells. We found that roscovitine and purvalanol (each 20 µM) induced apoptosis by activating caspase-9 and -3, and inhibiting the mitochondrial membrane potential in Caco-2 cells. CDK inhibitors decreased the intracellular putrescine and spermine levels without affecting spermidine levels. Although both roscovitine and purvalanol induced SSAT expression, they did not exert a significant effect on the APAO expression profile. SSAT transient silencing prevented roscovitine-induced apoptosis compared to parental cells. Thus, we concluded that roscovitine and purvalanol significantly induce apoptosis in Caco-2 cells by modulating the polyamine catabolism, and that SSAT could be an important target in evaluating the potential role of polyamines in apoptotic cell death. PMID:22294330

  10. The novel HDAC inhibitor AR-42-induced anti-colon cancer cell activity is associated with ceramide production

    SciTech Connect

    Xu, Weihong; Xu, Bin; Yao, Yiting; Yu, Xiaoling; Shen, Jie

    2015-08-07

    In the current study, we investigated the potential activity of AR-42, a novel histone deacetylase (HDAC) inhibitor, against colon cancer cells. Our in vitro 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. In vivo, 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 in vitro and in vivo, and ceramide production might be the key mechanism responsible for its actions. - Highlights: • AR-42 is anti-proliferative against primary/established colon cancer cells. • AR-42 induces significant apoptotic death in primary/established colon cancer cells. • Ceramide production mediates AR-42-induced cytotoxicity in colon cancer cells. • AR-42 oral administration potently inhibits SW-620 xenograft growth in SCID mice.

  11. Plant peroxisomes as a source of signalling molecules.

    PubMed

    Nyathi, Yvonne; Baker, Alison

    2006-12-01

    Peroxisomes are pleiomorphic, metabolically plastic organelles. Their essentially oxidative function led to the adoption of the name 'peroxisome'. The dynamic and diverse nature of peroxisome metabolism has led to the realisation that peroxisomes are an important source of signalling molecules that can function to integrate cellular activity and multicellular development. In plants defence against predators and a hostile environment is of necessity a metabolic and developmental response--a plant has no place to hide. Mutant screens are implicating peroxisomes in disease resistance and signalling in response to light. Characterisation of mutants disrupted in peroxisomal beta-oxidation has led to a growing appreciation of the importance of this pathway in the production of jasmonic acid, conversion of indole butyric acid to indole acetic acid and possibly in the production of other signalling molecules. Likewise the role of peroxisomes in the production and detoxification of reactive oxygen, and possibly reactive nitrogen species and changes in redox status, suggests considerable scope for peroxisomes to contribute to perception and response to a wide range of biotic and abiotic stresses. Whereas the peroxisome is the sole site of beta-oxidation in plants, the production and detoxification of ROS in many cell compartments makes the specific contribution of the peroxisome much more difficult to establish. However progress in identifying peroxisome specific isoforms of enzymes associated with ROS metabolism should allow a more definitive assessment of these contributions in the future. PMID:17030442

  12. Carbohydrate Metabolism Is Perturbed in Peroxisome-deficient Hepatocytes Due to Mitochondrial Dysfunction, AMP-activated Protein Kinase (AMPK) Activation, and Peroxisome Proliferator-activated Receptor γ Coactivator 1α (PGC-1α) Suppression*

    PubMed Central

    Peeters, Annelies; Fraisl, Peter; van den Berg, Sjoerd; Ver Loren van Themaat, Emiel; Van Kampen, Antoine; Rider, Mark H.; Takemori, Hiroshi; van Dijk, Ko Willems; Van Veldhoven, Paul P.; Carmeliet, Peter; Baes, Myriam

    2011-01-01

    Hepatic peroxisomes are essential for lipid conversions that include the formation of mature conjugated bile acids, the degradation of branched chain fatty acids, and the synthesis of docosahexaenoic acid. Through unresolved mechanisms, deletion of functional peroxisomes from mouse hepatocytes (L-Pex5−/− mice) causes severe structural and functional abnormalities at the inner mitochondrial membrane. We now demonstrate that the peroxisomal and mitochondrial anomalies trigger energy deficits, as shown by increased AMP/ATP and decreased NAD+/NADH ratios. This causes suppression of gluconeogenesis and glycogen synthesis and up-regulation of glycolysis. As a consequence, L-Pex5−/− mice combust more carbohydrates resulting in lower body weights despite increased food intake. The perturbation of carbohydrate metabolism does not require a long term adaptation to the absence of functional peroxisomes as similar metabolic changes were also rapidly induced by acute elimination of Pex5 via adenoviral administration of Cre. Despite its marked activation, peroxisome proliferator-activated receptor α (PPARα) was not causally involved in these metabolic perturbations, because all abnormalities still manifested when peroxisomes were eliminated in a peroxisome proliferator-activated receptor α null background. Instead, AMP-activated kinase activation was responsible for the down-regulation of glycogen synthesis and induction of glycolysis. Remarkably, PGC-1α was suppressed despite AMP-activated kinase activation, a paradigm not previously reported, and they jointly contributed to impaired gluconeogenesis. In conclusion, lack of functional peroxisomes from hepatocytes results in marked disturbances of carbohydrate homeostasis, which are consistent with adaptations to an energy deficit. Because this is primarily due to impaired mitochondrial ATP production, these L-Pex5-deficient livers can also be considered as a model for secondary mitochondrial hepatopathies. PMID

  13. 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

  14. A small molecule inhibitor of ubiquitin-specific protease-7 induces apoptosis in multiple myeloma cells and overcomes bortezomib resistance.

    PubMed

    Chauhan, Dharminder; Tian, Ze; Nicholson, Benjamin; Kumar, K G Suresh; Zhou, Bin; Carrasco, Ruben; McDermott, Jeffrey L; Leach, Craig A; Fulcinniti, Mariaterresa; Kodrasov, Matthew P; Weinstock, Joseph; Kingsbury, William D; Hideshima, Teru; Shah, Parantu K; Minvielle, Stephane; Altun, Mikael; Kessler, Benedikt M; Orlowski, Robert; Richardson, Paul; Munshi, Nikhil; Anderson, Kenneth C

    2012-09-11

    Bortezomib therapy has proven successful for the treatment of relapsed/refractory, relapsed, and newly diagnosed multiple myeloma (MM); however, dose-limiting toxicities and the development of resistance limit its long-term utility. Here, we show that P5091 is an inhibitor of deubiquitylating enzyme USP7, which induces apoptosis in MM cells resistant to conventional and bortezomib therapies. Biochemical and genetic studies show that blockade of HDM2 and p21 abrogates P5091-induced cytotoxicity. In animal tumor model studies, P5091 is well tolerated, inhibits tumor growth, and prolongs survival. Combining P5091 with lenalidomide, HDAC inhibitor SAHA, or dexamethasone triggers synergistic anti-MM activity. Our preclinical study therefore supports clinical evaluation of USP7 inhibitor, alone or in combination, as a potential MM therapy. PMID:22975377

  15. Effect of dietary polyunsaturated fatty acids on the expression of peroxisomal ABC transporters.

    PubMed

    Leclercq, Sabrina; Skrzypski, Jérémy; Courvoisier, Anne; Gondcaille, Catherine; Bonnetain, Franck; André, Agnès; Chardigny, Jean-Michel; Bellenger, Sandrine; Bellenger, Jérôme; Narce, Michel; Savary, Stéphane

    2008-10-01

    Peroxisomal ABC transporters encoded by the ABCD genes are thought to participate in the import of specific fatty acids in the peroxisomal matrix. ABCD1 deficiency is associated with X-linked adrenoleukodystrophy (X-ALD), the most frequent peroxisomal disorder which is characterized by the accumulation of saturated very-long-chain fatty acids (VLCFA). ABCD2 (the closest homolog of ABCD1) and ABCD3 have been shown to have partial functional redundancy with ABCD1; only when overexpressed, they can compensate for VLCFA accumulation. Other lipids, for instance polyunsaturated fatty acids (PUFA), should be possible candidate substrates for the ABCD2 and ABCD3 gene products, ALDRP and PMP70 respectively. Moreover, PUFA, which are known regulators of gene expression, could therefore represent potent inducers of the ABCD genes. To test this hypothesis, littermates of n-3-deficient rats were subjected to an n-3-deficient diet or equilibrated diets containing ALA (alpha-linolenic acid, 18:3n-3) as unique source of n-3 fatty acids or ALA plus DHA (docosahexaenoic acid, 22:6n-3) at two different doses. We analyzed the expression of peroxisomal ABC transporters and of the peroxisomal acyl-CoA oxidase gene 1 (Acox1) in adrenals, brain and liver. Whatever the diet, we did not observe any difference in gene expression in adrenals and brain. However, the hepatic expression level of Abcd2 and Abcd3 genes was found to be significantly higher in the n-3-deficient rats than in the rats fed the ALA diet or the DHA supplemented diets. This was accompanied by important changes in hepatic fatty acid composition. In summary, the hepatic expression of Abcd2 and Abcd3 but not of Abcd1 and Abcd4 appears to be highly sensitive towards dietary PUFA. This difference could be linked to the substrate specificity of the peroxisomal ABC transporters and a specific involvement of Abcd2 and Abcd3 in PUFA metabolism. PMID:18585430

  16. Multiple organelle-targeting signals in the N-terminal portion of peroxisomal membrane protein PMP70.

    PubMed

    Iwashita, Shohei; Tsuchida, Masashi; Tsukuda, Miwa; Yamashita, Yukari; Emi, Yoshikazu; Kida, Yuichiro; Komori, Masayuki; Kashiwayama, Yoshinori; Imanaka, Tsuneo; Sakaguchi, Masao

    2010-04-01

    Most membrane proteins are recognized by a signal recognition particle and are cotranslationally targeted to the endoplasmic reticulum (ER) membrane, whereas almost all peroxisomal membrane proteins are posttranslationally targeted to the destination. Here we examined organelle-targeting properties of the N-terminal portions of the peroxisomal isoform of the ABC transporter PMP70 (ABCD3) using enhanced green fluorescent protein (EGFP) fusion. When the N-terminal 80 amino acid residue (N80)-segment preceding transmembrane segment (TM) 1 was deleted and the TM1-TM2 region was fused to EGFP, the TM1 segment induced ER-targeting and integration in COS cells. When the N80-segment was fused to EGFP, the fusion protein was targeted to the outer mitochondrial membrane. When both the N80-segment and the following TM1-TM2 region were present, the fusion located exclusively to the peroxisome. The full-length PMP70 molecule was clearly located in the ER in the absence of the N80-segment, even when multiple peroxisome-targeting signals were retained. We concluded that the TM1 segment possesses a sufficient ER-targeting function and that the N80-segment is critical for suppressing the ER-targeting function to allow the TM1-TM2 region to localize to the peroxisome. Cooperation of the organelle-targeting signals enables PMP70 to correctly target to peroxisomal membranes. PMID:20007743

  17. Mice lacking the Raf-1 kinase inhibitor protein exhibit exaggerated hypoxia-induced pulmonary hypertension

    PubMed Central

    Morecroft, I; Doyle, B; Nilsen, M; Kolch, W; Mair, K; MacLean, MR

    2011-01-01

    BACKGROUND AND PURPOSE Increased pulmonary vascular remodelling, pulmonary arterial pressure and pulmonary vascular resistance characterize the development of pulmonary arterial hypertension (PAH). Activation of the Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)1/2 is thought to play an important role in PAH and Raf-1 kinase inhibitor protein (RKIP), negatively regulates this pathway. This study investigated whether genetic deletion of RKIP (and hence ERK1/2 up-regulation) resulted in a pulmonary hypertensive phenotype in mice and investigated a role for RKIP in mitogen-regulated proliferative responses in lung fibroblasts. EXPERIMENTAL APPROACH Pulmonary vascular haemodynamics and remodelling were assessed in mice genetically deficient in RKIP (RKIP−/−) after 2 weeks of either normoxia or hypoxia. Immunoblotting and immunohistochemistry were used to examine phosphorylation of Raf-1, RKIP and ERK1/2 in mouse pulmonary arteries. In vitro, RKIP inhibition of mitogen signalling was analysed in CCL39 hamster lung fibroblasts. KEY RESULTS RKIP−/− mice demonstrated elevated indices of PAH and ERK1/2 phosphorylation compared with wild-type (WT) mice. Hypoxic RKIP−/− mice exhibited exaggerated PAH indices. Hypoxia increased phosphorylation of Raf-1, RKIP and ERK1/2 in WT mouse pulmonary arteries and Raf-1 phosphorylation in RKIP−/− mouse pulmonary arteries. In CCL39 cells, inhibition of RKIP potentiated mitogen-induced proliferation and phosphorylation of RKIP, and Raf-1. CONCLUSIONS AND IMPLICATIONS The lack of RKIP protein resulted in a pulmonary hypertensive phenotype, exaggerated in hypoxia. Hypoxia induced phosphorylation of RKIP signalling elements in WT pulmonary arteries. RKIP inhibition potentiated mitogen-induced proliferation in lung fibroblasts. These results provide evidence for the involvement of RKIP in suppressing the development of hypoxia-induced PAH in mice. PMID:21385176

  18. A novel NF-κB inhibitor, DHMEQ, ameliorates pristane-induced lupus in mice.

    PubMed

    Qu, Huiqing; Bian, Weihua; Xu, Yanyan

    2014-07-01

    Nuclear factor (NF)-κB is strongly associated with the development of immune regulation and inflammation. The aim of the present study was to identify whether a NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), ameliorates systemic lupus erythematosus (SLE) in a pristane-induced mouse model. SLE was induced in 8-week-old female BALB/c mice by the injection of 0.5 ml pristane. The therapeutic effect of 12 mg/kg DHMEQ on the pristane-induced BALB/c mouse model of lupus was investigated to elucidate the effects on SLE. The intraperitoneal administration of DHMEQ three times per week was initiated when the mice were 16 weeks-old (8 weeks following the pristane injection) and the treatment was continued for 16 weeks. Serum IgG autoantibodies against nucleosomes, dsDNA and histones were detected at weeks 8, 16 and 32. In addition, the expression levels of interleukin (IL)-1β, 6 and 17, as well as tumor necrosis factor (TNF)-α, were analyzed at week 32. Renal lesions were also observed. DHMEQ was shown to antagonize the increasing levels of anti-nucleosome, anti-dsDNA and anti-histone autoantibodies, as well as the increasing levels of IL-1β, 6 and 17 and TNF-α. In addition, DHMEQ reduced the number of renal lesions caused by pristane, as reflected by milder proteinuria and reduced renal pathology. The renal expression levels of phosphorylated-p38 mitogen-activated protein kinase (MAPK), phosphorylated-c-Jun N-terminal kinase (JNK) and NF-κB p65 were significantly downregulated. Therefore, the results of the present study indicate that DHMEQ has a beneficial effect on pristane-induced lupus through regulating cytokine levels and the MAPK/JNK/NF-κB signaling pathway. PMID:24944605

  19. A novel NF-κB inhibitor, DHMEQ, ameliorates pristane-induced lupus in mice

    PubMed Central

    QU, HUIQING; BIAN, WEIHUA; XU, YANYAN

    2014-01-01

    Nuclear factor (NF)-κB is strongly associated with the development of immune regulation and inflammation. The aim of the present study was to identify whether a NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), ameliorates systemic lupus erythematosus (SLE) in a pristane-induced mouse model. SLE was induced in 8-week-old female BALB/c mice by the injection of 0.5 ml pristane. The therapeutic effect of 12 mg/kg DHMEQ on the pristane-induced BALB/c mouse model of lupus was investigated to elucidate the effects on SLE. The intraperitoneal administration of DHMEQ three times per week was initiated when the mice were 16 weeks-old (8 weeks following the pristane injection) and the treatment was continued for 16 weeks. Serum IgG autoantibodies against nucleosomes, dsDNA and histones were detected at weeks 8, 16 and 32. In addition, the expression levels of interleukin (IL)-1β, 6 and 17, as well as tumor necrosis factor (TNF)-α, were analyzed at week 32. Renal lesions were also observed. DHMEQ was shown to antagonize the increasing levels of anti-nucleosome, anti-dsDNA and anti-histone autoantibodies, as well as the increasing levels of IL-1β, 6 and 17 and TNF-α. In addition, DHMEQ reduced the number of renal lesions caused by pristane, as reflected by milder proteinuria and reduced renal pathology. The renal expression levels of phosphorylated-p38 mitogen-activated protein kinase (MAPK), phosphorylated-c-Jun N-terminal kinase (JNK) and NF-κB p65 were significantly downregulated. Therefore, the results of the present study indicate that DHMEQ has a beneficial effect on pristane-induced lupus through regulating cytokine levels and the MAPK/JNK/NF-κB signaling pathway. PMID:24944605

  20. Peroxisome proliferator-activated receptor alpha is involved in the regulation of lipid metabolism by ginseng.

    PubMed

    Yoon, Michung; Lee, Hyunghee; Jeong, Sunhyo; Kim, Jung-Jae; Nicol, Christopher J; Nam, Kung Woo; Kim, Moonza; Cho, Byung Goo; Oh, Goo Taeg

    2003-04-01

    1. Peroxisome proliferator-activated receptor alpha (PPARalpha) regulates the expression of the key genes involved in lipid metabolism following activation of this receptor by various ligands. Ginseng, a highly valuable medicine in oriental societies, is also reported to modulate lipid metabolism, although the mechanism of its action remains unknown. In order to test our hypothesis that ginseng exerts its effects by altering PPARalpha-mediated pathways, the effects of Korean red ginseng on PPARalpha function and serum lipid profiles were investigated using in vivo and in vitro approaches. 2. In vivo administration of ginseng extract (GE) and ginsenosides (GS) not only inhibited mRNA levels of acyl-CoA oxidase, a rate-limiting enzyme for PPARalpha-mediated peroxisomal fatty acid beta-oxidation, induced by the potent PPARalpha ligand Wy14,643 in a dose- and time-dependent manner, but also inhibited the induction of PPARalpha target genes expected following treatment with Wy14,643. 3. Consistent with the in vivo data, both GE and GS caused dose-dependent decreases in the endogenous expression of a luciferase reporter gene containing the PPAR responsive element (PPRE), while GS significantly decreased the magnitude of reporter gene activation in the presence of Wy14,643. 4. Serological studies demonstrated that, compared with vehicle-treated mice, treatment with GS significantly increased serum concentrations of total cholesterol, triglycerides, and high-density lipoprotein (HDL) cholesterol. Compared to groups treated with Wy14,643 alone, which significantly decreased serum triglyceride and HDL cholesterol levels versus controls, coadministration of either GE or GS with Wy14,643 modestly increased serum triglycerides and HDL cholesterol. 5. These results indicate that the effects of ginseng on serum lipid profiles may be mediated by changes in the expression of PPARalpha target genes, providing the first evidence that in vivo and in vitro treatments of ginseng

  1. Molecular characterization and phylogenetic studies of a wound-inducible proteinase inhibitor I gene in Lycopersicon species.

    PubMed

    Lee, J S; Brown, W E; Graham, J S; Pearce, G; Fox, E A; Dreher, T W; Ahern, K G; Pearson, G D; Ryan, C A

    1986-10-01

    A gene coding for proteinase inhibitor I, whose expression is induced in tomato leaves (Lycopersicon esculentum L. var. Bonny Best) in response to wounding or insect attacks, was isolated from a genomic library and characterized. The nucleotide sequence revealed that the gene is complete and encodes the sequence of an inhibitor I cDNA that was previously isolated from a cDNA library prepared from wound-induced mRNA from tomato leaves. This gene is located 13.1 kilobase pairs (kbp) upstream from an inhibitor II gene. The wound-inducible gene is interrupted by two intervening sequences of 445 and 404 bp, situated within the codons of amino acids 17 and 47, respectively, of the open reading frame. In addition to the presence of putative regulatory sequences, TATAAA and CCACT, two copies of an imperfect direct repeat approximately 100 bp long were identified in the 5'-flanking region. Phylogenetic comparisons of wound-inducible inhibitor I genes within the genomes of various Lycopersicon species revealed that the repeat is found in seven ancestral species of tomato. PMID:3463966

  2. 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-κB) 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

  3. 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.

  4. Genistein cooperates with the histone deacetylase inhibitor vorinostat to induce cell death in prostate cancer cells

    PubMed Central

    2012-01-01

    Background Among American men, prostate cancer is the most common, non-cutaneous malignancy that accounted for an estimated 241,000 new cases and 34,000 deaths in 2011. Previous studies have suggested that Wnt pathway inhibitory genes are silenced by CpG hypermethylation, and other studies have suggested that genistein can demethylate hypermethylated DNA. Genistein is a soy isoflavone with diverse effects on cellular proliferation, survival, and gene expression that suggest it could be a potential therapeutic agent for prostate cancer. We undertook the present study to investigate the effects of genistein on the epigenome of prostate cancer cells and to discover novel combination approaches of other compounds with genistein that might be of translational utility. Here, we have investigated the effects of genistein on several prostate cancer cell lines, including the ARCaP-E/ARCaP-M model of the epithelial to mesenchymal transition (EMT), to analyze effects on their epigenetic state. In addition, we investigated the effects of combined treatment of genistein with the histone deacetylase inhibitor vorinostat on survival in prostate cancer cells. Methods Using whole genome expression profiling and whole genome methylation profiling, we have determined the genome-wide differences in genetic and epigenetic responses to genistein in prostate cancer cells before and after undergoing the EMT. Also, cells were treated with genistein, vorinostat, and combination treatment, where cell death and cell proliferation was determined. Results Contrary to earlier reports, genistein did not have an effect on CpG methylation at 20 μM, but it did affect histone H3K9 acetylation and induced increased expression of histone acetyltransferase 1 (HAT1). In addition, genistein also had differential effects on survival and cooperated with the histone deacteylase inhibitor vorinostat to induce cell death and inhibit proliferation. Conclusion Our results suggest that there are a number of

  5. 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 (15 mg/kg/day, subcutaneous) were given to male SD rats for 28 days. 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

  6. A lysophosphatidic acid analogue is revealed as a potent inhibitor of phosphatidylcholine synthesis, inducing apoptosis.

    PubMed Central

    Gueguen, Geneviéve; Granci, Virginie; Rogalle, Pierre; Briand-Mésange, Fabienne; Wilson, Michéle; Klaébé, Alain; Tercé, François; Chap, Hugues; Salles, Jean-Pierre; Simon, Marie-Françoise; Gaits, Frédérique

    2002-01-01

    A previous study demonstrated that cross-desensitization experiments performed with the lysophosphatidic acid (LPA) analogues (R)- and (S)-N-palmitoyl-norleucinol 1-phosphate (PNPAs) inhibited LPA-induced platelet aggregation without any stereospecificity. Here we report opposite biological effects of the two enantiomers on mitogenesis of IMR-90 fibroblasts in relation to their respective metabolism. (R)PNPA was proliferative, while (S)PNPA induced apoptosis by specifically inhibiting phosphatidylcholine biosynthesis at the last step of the CDP-choline pathway controlled by cholinephosphotransferase. This effect was not direct but required dephosphorylation of PNPAs by ecto-lipid phosphate phosphatase before cellular uptake of the generated N-palmitoyl-norleucinols (PNOHs). Inhibition of cholinephosphotransferase by the derivative (S)PNOH was confirmed by an in vitro assay. (S)PNPA proapoptotic effects led us to clarify the mechanism linking cholinephosphotransferase inhibition to apoptosis. Three proapoptotic responses were observed: the activation of caspase-3, the production of ceramides from newly synthesized pools (as demonstrated by the inhibitor Fumonisin B1) and finally the activation of stress-activated protein kinase, p38 and c-Jun N-terminal kinases 1/2, as a result of ceramide increase. Thus our data demonstrate that synthetic analogues of LPA might display stereospecific effects leading to apoptosis independently of classical LPA-activated pathways. PMID:12197836

  7. An NLRP3-specific inflammasome inhibitor attenuates crystal-induced kidney fibrosis in mice.

    PubMed

    Ludwig-Portugall, Isis; Bartok, Eva; Dhana, Ermanila; Evers, Beatrix D G; Primiano, Michael J; Hall, J Perry; Franklin, Bernardo S; Knolle, Percy A; Hornung, Veit; Hartmann, Gunther; Boor, Peter; Latz, Eicke; Kurts, Christian

    2016-09-01

    Intrarenal crystal formation activates the Nlrp3 inflammasome in myeloid cells and triggers a profound inflammatory response. Here, we studied whether a specific inhibitor of the Nlrp3 inflammasome, CP-456,773, can prevent kidney fibrosis in a murine model of crystal nephropathy induced by diets rich in oxalate or adenine. Inflammasome activation in renal dendritic cells and the resulting interleukin (IL)-1β and IL-18 production were markedly reduced by CP-456,773 treatment both ex vivo and in vivo. We directly visualized intrarenal inflammasome activation and its inhibition by CP-456,773 in vivo by adoptive transfer of bone marrow cells transduced with interleukin-1β-Gaussia luciferase, a proteolytic luciferase-based reporter for inflammasome activation, into irradiated mice. CP-456,773 treatment strongly attenuated kidney fibrosis when given early in the genesis of crystal nephropathy, but was unable to reverse established crystal-induced fibrosis. The urinary IL-18 concentration appeared to be a useful noninvasive biomarker for renal inflammasome activation. Finally, NLRP3 inhibition did not compromise adaptive immune responses as previously reported for the global inhibition of IL-1 signaling. Thus, early NLRP3 inhibition by CP-456,773 may be an effective treatment for crystal nephropathy. Use of iGLuc transfected cells introduces a novel imaging technique for inflammasome activation in mice. PMID:27262364

  8. Small molecule inhibitors of Clostridium difficile toxin B-induced cellular damage.

    PubMed

    Tam, John; Beilhartz, Greg L; Auger, Anick; Gupta, Pulkit; Therien, Alex G; Melnyk, Roman A

    2015-02-19

    Clostridium difficile causes life-threatening diarrhea through the actions of its homologous toxins TcdA and TcdB on human colonocytes. Therapeutic agents that block toxin-induced damage are urgently needed to prevent the harmful consequences of toxin action that are not addressed with current antibiotic-based treatments. Here, we developed an imaging-based phenotypic screen to identify small molecules that protected human cells from TcdB-induced cell rounding. A series of structurally diverse compounds with antitoxin activity were identified and found to act through one of a small subset of mechanisms, including direct binding and sequestration of TcdB, inhibition of endosomal maturation, and noncompetitive inhibition of the toxin glucosyltransferase activity. Distinct classes of inhibitors were used further to dissect the determinants of the toxin-mediated necrosis phenotype occurring at higher doses of toxin. These findings validate and inform novel targeting strategies for discovering small molecule agents to treat C. difficile infection. PMID:25619932

  9. 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.

  10. Panhistone deacetylase inhibitors inhibit proinflammatory signaling pathways to ameliorate interleukin-18-induced cardiac hypertrophy

    PubMed Central

    Majumdar, Gipsy; Rooney, Robert J.; Johnson, I. Maria

    2011-01-01

    We investigated the genome-wide consequences of pan-histone deacetylase inhibitors (HDACIs) trichostatin A (TSA) and m-carboxycinnamic acid bis-hydroxamide (CBHA) in the hearts of BALB/c mice eliciting hypertrophy in response to interleukin-18 (IL-18). Both TSA and CBHA profoundly altered cardiac chromatin structure that occurred concomitantly with normalization of IL-18-induced gene expression and amelioration of cardiac hypertrophy. The hearts of mice exposed to IL-18 +/− TSA or CBHA elicited distinct gene expression profiles. Of 184 genes that were differentially regulated by IL-18 and TSA, 33 were regulated in an opposite manner. The hearts of mice treated with IL-18 and/or CBHA elicited 147 differentially expressed genes (DEGs), a third of which were oppositely regulated by IL-18 and CBHA. Ingenuity Pathways and Kyoto Encyclopedia of Genes and Genomes analyses of DEGs showed that IL-18 impinged on TNF-α- and IFNγ-specific gene networks relegated to controlling immunity and inflammation, cardiac metabolism and energetics, and cell proliferation and apoptosis. These TNF-α- and IFNγ-specific gene networks, extensively connected with PI3K, MAPK, and NF-κB signaling pathways, were oppositely regulated by IL-18 and pan-HDACIs. Evidently, both TSA and CBHA caused a two- to fourfold induction of phosphatase and tensin homolog expression to counteract IL-18-induced proinflammatory signaling and cardiac hypertrophy. PMID:21954451

  11. Effect of a p38 MAPK inhibitor on FFA-induced hepatic insulin resistance in vivo

    PubMed Central

    Pereira, S; Yu, W Q; Moore, J; Mori, Y; Tsiani, E; Giacca, A

    2016-01-01

    The mechanisms whereby prolonged plasma free fatty acids elevation, as found in obesity, causes hepatic insulin resistance are not fully clarified. We herein investigated whether inhibition of p38 mitogen-activated protein kinase (MAPK) prevented hepatic insulin resistance following prolonged lipid infusion. Chronically cannulated rats were subdivided into one of four intravenous (i.v.) treatments that lasted 48 h: Saline (5.5 μl min−1), Intralipid plus heparin (IH, 20% Intralipid+20 U ml−1 heparin; 5.5 μl min−1), IH+p38 MAPK inhibitor (SB239063) and SB239063 alone. During the last 2 h of treatment, a hyperinsulinemic (5 mU kg−1 min−1) euglycemic clamp together with [3-3H] glucose methodology was carried out to distinguish hepatic from peripheral insulin sensitivity. We found that SB239063 prevented IH-induced hepatic insulin resistance, but not peripheral insulin resistance. SB239063 also prevented IH-induced phosphorylation of activating transcription factor 2 (ATF2), a marker of p38 MAPK activity, in the liver. Moreover, in another lipid infusion model in mice, SB239063 prevented hepatic but not peripheral insulin resistance caused by 48 h combined ethyloleate plus ethylpalmitate infusion. Our results suggest that inhibition of p38 MAPK may be a useful strategy in alleviating hepatic insulin resistance in obesity-associated disorders. PMID:27136448

  12. Effect of a p38 MAPK inhibitor on FFA-induced hepatic insulin resistance in vivo.

    PubMed

    Pereira, S; Yu, W Q; Moore, J; Mori, Y; Tsiani, E; Giacca, A

    2016-01-01

    The mechanisms whereby prolonged plasma free fatty acids elevation, as found in obesity, causes hepatic insulin resistance are not fully clarified. We herein investigated whether inhibition of p38 mitogen-activated protein kinase (MAPK) prevented hepatic insulin resistance following prolonged lipid infusion. Chronically cannulated rats were subdivided into one of four intravenous (i.v.) treatments that lasted 48 h: Saline (5.5 μl min(-1)), Intralipid plus heparin (IH, 20% Intralipid+20 U ml(-1) heparin; 5.5 μl min(-1)), IH+p38 MAPK inhibitor (SB239063) and SB239063 alone. During the last 2 h of treatment, a hyperinsulinemic (5 mU kg(-1) min(-1)) euglycemic clamp together with [3-(3)H] glucose methodology was carried out to distinguish hepatic from peripheral insulin sensitivity. We found that SB239063 prevented IH-induced hepatic insulin resistance, but not peripheral insulin resistance. SB239063 also prevented IH-induced phosphorylation of activating transcription factor 2 (ATF2), a marker of p38 MAPK activity, in the liver. Moreover, in another lipid infusion model in mice, SB239063 prevented hepatic but not peripheral insulin resistance caused by 48 h combined ethyloleate plus ethylpalmitate infusion. Our results suggest that inhibition of p38 MAPK may be a useful strategy in alleviating hepatic insulin resistance in obesity-associated disorders. PMID:27136448

  13. A Sphingolipid Inhibitor Induces a Cytokinesis Arrest and Blocks Stage Differentiation in Giardia lamblia▿

    PubMed Central

    Sonda, Sabrina; Štefanić, Saša; Hehl, Adrian B.

    2008-01-01

    Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 μM. The inhibition of parasite replication was irreversible at 10 μM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents. PMID:18086854

  14. A sphingolipid inhibitor induces a cytokinesis arrest and blocks stage differentiation in Giardia lamblia.

    PubMed

    Sonda, Sabrina; Stefanic, Sasa; Hehl, Adrian B

    2008-02-01

    Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 muM. The inhibition of parasite replication was irreversible at 10 muM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents. PMID:18086854

  15. 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

  16. Nitric oxide synthase inhibitors can antagonize neurogenic and calcitonin gene-related peptide induced dilation of dural meningeal vessels

    PubMed Central

    Akerman, S; Williamson, D J; Kaube, H; Goadsby, P J

    2002-01-01

    The detailed pathophysiology of migraine is beginning to be understood and is likely to involve activation of trigeminovascular afferents. Clinically effective anti-migraine compounds are believed to have actions that include peripheral inhibition of calcitonin gene-related peptide (CGRP) release from trigeminal neurones, or preventing dural vessel dilation, or both. CGRP antagonists can block both neurogenic and CGRP-induced dural vessel dilation. Nitric oxide (NO) can induce headache in migraine patients and often triggers a delayed migraine. The initial headache is thought to be caused via a direct action of the NO–cGMP pathway that causes vasodilation by vascular smooth muscle relaxation, while the delayed headache is likely to be a result of triggering trigeminovascular activation. Nitric oxide synthase (NOS) inhibitors are effective in the treatment of acute migraine. The present studies used intravital microscopy to examine the effects of specific NOS inhibitors on neurogenic dural vasodilation (NDV) and CGRP-induced dilation. The non-specific and neuronal NOS (nNOS) inhibitors were able to partially inhibit NDV, while the non-specific and endothelial NOS (eNOS) inhibitors were able to partially inhibit the CGRP induced dilation. There was no effect of the inducible NOS (iNOS) inhibitor. The data suggest that the delayed headache response triggered by NO donors in humans may be due, in part, to increased nNOS activity in the trigeminal system that causes CGRP release and dural vessel dilation. Further, eNOS activity in the endothelium causes NO production and smooth muscle relaxation by direct activation of the NO–cGMP pathway, and may be involved in the initial headache response. PMID:12183331

  17. Model boiler testing to evaluate inhibitors for caustic induced stress corrosion cracking of Alloy 600 tubes

    SciTech Connect

    Daret, J.; Paine, J.P.N.; Partridge, M.J.

    1995-12-31

    A series of model boiler tests, using a mixture of precracked and non-precracked (virgin) tube-to-tube support plate intersections was performed. The testing supported the qualification of inhibitors for mitigating the secondary side corrosion of alloy 600 steam generator tubes. Many utilities suspect that the caustic impurities come from the feedwater. Candidate inhibitors included boric acid (as a reference), cerous acetate, and two forms of titanium dioxide: a laboratory produced titania-silica sol-gel, and manometer sized anatase The latter was combined with a 150 C pre-soaking with a titanium lactate, and was tested with and without a zeta potential treatment by sodium aluminate. Effectiveness of boric acid to prevent and retard caustic induced intergranular corrosion was confirmed in all crevice configurations (open and packed). The cerous acetate treatment multiplied by two to four the time necessary to detect a primary-to-secondary leak on virgin tubes, and reduced the propagation rate on precracked tubes. Cerium was found intimately mixed, as cerianite, with the free span and crevice deposits, when the crevices were sufficiently accessible. Due to its very low solubility and large particle size, the titania-silica sol-gel was unable to penetrate the crevices and had no effect on the degradation process. The nanometric particle size titania treatment and/or the preceding soaking with soluble titanium lactate drastically increased the titanium concentration in free span and open crevice deposit (with no added sodium aluminate, titania reacted with magnetite to form ilmenite) and showed undeniable capacity to prevent tubing degradation. Its effectiveness, in the case of packed crevices and for arresting cracks, was not so conclusive.

  18. 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

  19. Topoisomerase I inhibitor, camptothecin, induces apoptogenic signaling in human embryonic stem cells.

    PubMed

    García, Carolina Paola; Videla Richardson, Guillermo Agustín; Romorini, Leonardo; Miriuka, Santiago Gabriel; Sevlever, Gustavo Emilio; Scassa, María Elida

    2014-03-01

    Embryonic stem cells (ESCs) need to maintain their genomic integrity in response to DNA damage to safeguard the integrity of the organism. DNA double strand breaks (DSBs) are one of the most lethal forms of DNA damage and, if not repaired correctly, they can lead to cell death, genomic instability and cancer. How human ESCs (hESCs) maintain genomic integrity in response to agents that cause DSBs is relatively unclear. In the present study we aim to determine the hESC response to the DSB inducing agent camptothecin (CPT). We find that hESCs are hypersensitive to CPT, as evidenced by high levels of apoptosis. CPT treatment leads to DNA-damage sensor kinase (ATM and DNA-PKcs) phosphorylation on serine 1981 and serine 2056, respectively. Activation of ATM and DNA-PKcs was followed by histone H2AX phosphorylation on Ser 139, a sensitive reporter of DNA damage. Nuclear accumulation and ATM-dependent phosphorylation of p53 on serine 15 were also observed. Remarkably, hESC viability was further decreased when ATM or DNA-PKcs kinase activity was impaired by the use of specific inhibitors. The hypersensitivity to CPT treatment was markedly reduced by blocking p53 translocation to mitochondria with pifithrin-μ. Importantly, programmed cell death was achieved in the absence of the cyclin dependent kinase inhibitor, p21(Waf1), a bona fide p53 target gene. Conversely, differentiated hESCs were no longer highly sensitive to CPT. This attenuated apoptotic response was accompanied by changes in cell cycle profile and by the presence of p21(Waf1). The results presented here suggest that p53 has a key involvement in preventing the propagation of damaged hESCs when genome is threatened. As a whole, our findings support the concept that the phenomenon of apoptosis is a prominent player in normal embryonic development. PMID:24380814

  20. Tyrosine Kinase Inhibitors Induce Down-Regulation of c-Kit by Targeting the ATP Pocket

    PubMed Central

    Descarpentries, Clotilde; Frisan, Emilie; Adam, Kevin; Verdier, Frederique; Floquet, Célia; Dubreuil, Patrice; Lacombe, Catherine; Fontenay, Michaela; Mayeux, Patrick; Kosmider, Olivier

    2013-01-01

    The stem cell factor receptor (SCF) c-Kit plays a pivotal role in regulating cell proliferation and survival in many cell types. In particular, c-Kit is required for early amplification of erythroid progenitors, while it must disappear from cell surface for the cell entering the final steps of maturation in an erythropoietin-dependent manner. We initially observed that imatinib (IM), an inhibitor targeting the tyrosine kinase activity of c-Kit concomitantly down-regulated the expression of c-Kit and accelerated the Epo-driven differentiation of erythroblasts in the absence of SCF. We investigated the mechanism by which IM or related masitinib (MA) induce c-Kit down-regulation in the human UT-7/Epo cell line. We found that the down-regulation of c-Kit in the presence of IM or MA was inhibited by a pre-incubation with methyl-β-cyclodextrin suggesting that c-Kit was internalized in the absence of ligand. By contrast to SCF, the internalization induced by TKI was independent of the E3 ubiquitin ligase c-Cbl. Furthermore, c-Kit was degraded through lysosomal, but not proteasomal pathway. In pulse-chase experiments, IM did not modulate c-Kit synthesis or maturation. Analysis of phosphotyrosine peptides in UT-7/Epo cells treated or not with IM show that IM did not modify overall tyrosine phosphorylation in these cells. Furthermore, we showed that a T670I mutation preventing the full access of IM to the ATP binding pocket, did not allow the internalization process in the presence of IM. Altogether these data show that TKI-induced internalization of c-Kit is linked to a modification of the integrity of ATP binding pocket. PMID:23637779

  1. Trichostatin A, a histone deacetylase inhibitor, modulates unloaded-induced skeletal muscle atrophy.

    PubMed

    Dupré-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

  2. Xanthine crystals induced by topiroxostat, a xanthine oxidoreductase inhibitor, in rats, cause transitional cell tumors.

    PubMed

    Shimo, Takeo; Moto, Mitsuyoshi; Ashizawa, Naoki; Matsumoto, Koji; Iwanaga, Takashi; Saito, Kazuhiro

    2014-04-01

    The present study was performed to elucidate the underlying mechanism of transitional cell tumors found in the carcinogenicity testing of topiroxostat, a xanthine oxidoreductase inhibitor, in which topiroxostat was orally given to F344 rats at 0.3, 1, and 3 mg/kg for 2 years. In the urinary bladder, transitional cell papillomas and/or carcinomas were seen in males receiving 0.3, 1, and 3 mg/kg (1/49, 3/49, and 10/50, respectively). In the kidney, transitional cell papillomas and/or carcinomas in the pelvis were seen in 2/50 males and 1/50 females receiving 3 mg/kg. In the mechanistic study by 52-week oral treatment with topiroxostat at 3 mg/kg to F344 male rats, with and without citrate, simple and papillary transitional cell hyperplasias of the urinary bladder epithelium were observed in 5/17 in the topiroxostat-alone treatment group, along with xanthine-induced nephropathy, in contrast to neither xanthine crystals nor lesions in urinary organs by co-treatment group with citrate. As for sex differences of urinary bladder tumors, the BrdU labeling index for epithelial cells of the urinary bladder by 5-week oral treatment with topiroxostat at 10 mg/kg to F344 rats was increased in males only, showing consistency with histopathological findings. Therefore, the present study indicates that transitional cell tumors induced by topiroxostat in rats were due to physical stimulation to transitional cells of xanthine crystals/calculi and provides that other factors were not implicated in this tumorigenesis. Furthermore, the present study suggests that such tumors do not predict for humans since topiroxostat-induced xanthine deposition is a rodent-specific event. PMID:24448833

  3. 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 γ-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

  4. 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

  5. Flavone as PARP-1 inhibitor: its effect on lipopolysaccharide induced gene-expression.

    PubMed

    Geraets, Liesbeth; Moonen, Harald J J; Brauers, Karen; Gottschalk, Ralph W H; Wouters, Emiel F M; Bast, Aalt; Hageman, Geja J

    2007-11-14

    The nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1) which was initially known for its role in the repair of oxidative stress-induced DNA damage, has also been reported to play a mediating role in the inflammatory response. Studies with PARP-1 knockout models have shown that PARP-1 is a co-activator of Nuclear Factor-kappa B (NF-kappaB), although this appears not to require its enzyme activity. In addition, drug-induced inhibition of the enzyme activity of PARP-1 was observed to reduce the production of pro-inflammatory mediators. In this study, the flavonoid compound flavone was demonstrated to significantly inhibit the enzyme activity of PARP-1. Further evaluation of flavone in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-treated human pulmonary epithelial and vascular endothelial cells revealed that both the decrease in NAD(+) levels, as well as the formation of PAR-polymers was dose-dependently attenuated by flavone. In addition, flavone was found to reduce the lipopolysaccharide (LPS)-induced interleukin (IL)-8 production in pulmonary epithelial cells, which was confirmed by transcription analysis. Furthermore, the transcription Inhibitor kappa B alpha (of IkappaBalpha) was significantly increased by flavone. The results of the present study indicate that the flavonoid flavone could be a potential candidate for application in treatment of chronic inflammatory diseases. PARP-1 inhibition could have beneficial effects in such diseases as Chronic Obstructive Pulmonary Disease (COPD) and diabetes, by preservation of cellular NAD(+) levels and attenuating inflammatory conditions. PMID:17643414

  6. Super-resolution Microscopy Reveals Compartmentalization of Peroxisomal Membrane Proteins.

    PubMed

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina; Cruz-Zaragoza, Luis Daniel; Garcia, Esther; Clausen, Mathias P; Schliebs, Wolfgang; Erdmann, Ralf; Eggeling, Christian

    2016-08-12

    Membrane-associated events during peroxisomal protein import processes play an essential role in peroxisome functionality. Many details of these processes are not known due to missing spatial resolution of technologies capable of investigating peroxisomes directly in the cell. Here, we present the use of super-resolution optical stimulated emission depletion microscopy to investigate with sub-60-nm resolution the heterogeneous spatial organization of the peroxisomal proteins PEX5, PEX14, and PEX11 around actively importing peroxisomes, showing distinct differences between these peroxins. Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5 or PEX11 but at the same time a clear compartmentalized organization. This compartmentalization, which was less evident in cases of strong colocalization, indicates dynamic protein reorganization linked to changes occurring in the peroxisomes. Through the use of multicolor stimulated emission depletion microscopy, we have been able to characterize peroxisomes and their constituents to a yet unseen level of detail while maintaining a highly statistical approach, paving the way for equally complex biological studies in the future. PMID:27311714

  7. Super-resolution Microscopy Reveals Compartmentalization of Peroxisomal Membrane Proteins*

    PubMed Central

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina; Cruz-Zaragoza, Luis Daniel; Garcia, Esther; Clausen, Mathias P.; Schliebs, Wolfgang; Erdmann, Ralf; Eggeling, Christian

    2016-01-01

    Membrane-associated events during peroxisomal protein import processes play an essential role in peroxisome functionality. Many details of these processes are not known due to missing spatial resolution of technologies capable of investigating peroxisomes directly in the cell. Here, we present the use of super-resolution optical stimulated emission depletion microscopy to investigate with sub-60-nm resolution the heterogeneous spatial organization of the peroxisomal proteins PEX5, PEX14, and PEX11 around actively importing peroxisomes, showing distinct differences between these peroxins. Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5 or PEX11 but at the same time a clear compartmentalized organization. This compartmentalization, which was less evident in cases of strong colocalization, indicates dynamic protein reorganization linked to changes occurring in the peroxisomes. Through the use of multicolor stimulated emission depletion microscopy, we have been able to characterize peroxisomes and their constituents to a yet unseen level of detail while maintaining a highly statistical approach, paving the way for equally complex biological studies in the future. PMID:27311714

  8. 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.

  9. Evodiamine inhibits the proliferation of leukemia cell line K562 by regulating peroxisome proliferators-activated receptor gamma (PPARγ) pathway.

    PubMed

    Sun, Chengming; Zhang, Guili; Luan, Shuping; Luan, Caifu; Shao, Huiyuan; Dong, Fei; Liu, Xuena

    2016-08-01

    Evodiamine, a quinolone alkaloid, is one of the major bioactive compounds of Evodia rutaecarpa Bentham (Rutaceae). It exhibits excellent biological activities, especially the anticancer activity. This study aims to investigate the effect of evodiamine on the proliferation of leukemia cell line K562 and to explore the underlying mechanism. The effect of evodiamine on K562 cells proliferation was analyzed by trypan blue dye exclusion assay and MTT assay. The expression levels of peroxisome proliferators-activated receptor gamma (PPARγ), cyclin D1, and p21 were detected by western blot assay. The results demonstrated that evodiamine inhibited the proliferation and decreased the viability of K562 cells in a dose- and time-dependent manner. 2-Chloro-5-nitro-N-phenylbenzamide (GW9662) and/or PPARγ-siRNA pretreatment alleviated the cell growth suppression triggered by evodiamine. Meanwhile, evodiamine intervention elevated the expression of PPARγ in K562 cells, while pretreatment with GW9662 attenuated the enhanced upregulation of PPARγ expression induced by evodiamine. In addition, GW9662 and PPARγ-siRNA pretreatment also significantly attenuated the downregulation of the cell cycle control protein cyclin D1 and the upregulation of cyclin-dependent kinase inhibitor p21 induced by evodiamine. In conclusion, PPARγ signaling pathway may involve in the proliferation inhibition of evodiamine on K562 cells via inhibiting cylcin D1 and stimulating of p21. PMID:26671528

  10. IL-4 inhibits osteoclast formation through a direct action on osteoclast precursors via peroxisome proliferator-activated receptor γ1

    PubMed Central

    Bendixen, Amy C.; Shevde, Nirupama K.; Dienger, Krista M.; Willson, Timothy M.; Funk, Colin D.; Pike, J. Wesley

    2001-01-01

    IL-4 is a pleiotropic immune cytokine secreted by activated TH2 cells that inhibits bone resorption both in vitro and in vivo. The cellular targets of IL-4 action as well as its intracellular mechanism of action remain to be determined. We show here that IL-4 inhibits receptor activator of NF-κB ligand-induced osteoclast differentiation through an action on osteoclast precursors that is independent of stromal cells. Interestingly, this inhibitory effect can be mimicked by both natural as well as synthetic peroxisome proliferator-activated receptor γ1 (PPARγ1) ligands and can be blocked by the irreversible PPARγ antagonist GW 9662. These findings suggest that the actions of IL-4 on osteoclast differentiation are mediated by PPARγ1, an interpretation strengthened by the observation that IL-4 can activate a PPARγ1-sensitive luciferase reporter gene in RAW264.7 cells. We also show that inhibitors of enzymes such as 12/15-lipoxygenase and the cyclooxygenases that produce known PPARγ1 ligands do not abrogate the IL-4 effect. These findings, together with the observation that bone marrow cells from 12/15-lipoxygenase-deficient mice retain sensitivity to IL-4, suggest that the cytokine may induce novel PPARγ1 ligands. Our results reveal that PPARγ1 plays an important role in the suppression of osteoclast formation by IL-4 and may explain the beneficial effects of the thiazolidinedione class of PPARγ1 ligands on bone loss in diabetic patients. PMID:11226258

  11. The hsp70 inhibitor VER155008 induces paraptosis requiring de novo protein synthesis in anaplastic thyroid carcinoma cells.

    PubMed

    Kim, Si Hyoung; Kang, Jun Goo; Kim, Chul Sik; Ihm, Sung-Hee; Choi, Moon Gi; Yoo, Hyung Joon; Lee, Seong Jin

    2014-11-01

    In this study, we evaluated the effect of the hsp70 inhibitor VER155008 on survival of anaplastic thyroid carcinoma (ATC) cells. In ATC cells, VER155008 increased the percentages of dead cells and vacuolated cells. VER155008 did not lead to the cleavage of caspase-3 protein regardless of pretreatment with z-VAD-fmk. VER155008 increased LC3-II protein levels but the protein levels were not changed by autophagy inhibitors. VER155008 caused the dilatation of endoplasmic reticulum (ER), and the increased mRNA levels of Bip and CHOP, suggesting paraptosis. VER155008-induced paraptosis was attenuated by pretreatment with cycloheximide. In conclusion, VER155008 induces paraptosis characterized by cytoplasmic vacuolation, independence of caspase, dilatation of ER and induction of ER stress markers in ATC cells. Moreover, VER155008-induced paraptosis requires de novo protein synthesis in ATC cells. PMID:25450359

  12. Nucleoside Reverse Transcriptase Inhibitors Suppress Laser-Induced Choroidal Neovascularization in Mice

    PubMed Central

    Mizutani, Takeshi; Fowler, Benjamin J.; Kim, Younghee; Yasuma, Reo; Krueger, Laura A.; Gelfand, Bradley D.; Ambati, Jayakrishna

    2015-01-01

    Purpose To evaluate the efficacy of nucleoside reverse transcriptase inhibitors (NRTIs) in the laser-induced mouse model of choroidal neovascularization (CNV). Methods We evaluated the NRTIs lamivudine (3TC), zidovudine (AZT), and abacavir (ABC) and the P2X7 antagonist A438079. Choroidal neovascularization was induced by laser injury in C57BL/6J wild-type, Nlrp3−/−, and P2rx7−/− mice, and CNV volume was measured after 7 days by confocal microscopy. Drugs were administered by intravitreous injection immediately after the laser injury. Vascular endothelial growth factor-A in RPE-choroid lysates was measured 3 days after laser injury by ELISA. HEK293 cells expressing human and mouse P2X7 were exposed to the selective P2X7 receptor agonist 2′, 3′-(benzoyl-4-benzoyl)-ATP (Bz-ATP) with or without 3TC, and VEGF-A levels in media were measured by ELISA. Results Intravitreous injection of 3TC, AZT, and ABC significantly suppressed laser-induced CNV in C57BL/6J wild-type and Nlrp3−/− mice (P < 0.05) but not in P2rx7−/− mice. Intravitreous injection of A438079 also suppressed the laser-induced CNV (P < 0.05). The NRTIs 3TC, AZT, and ABC blocked VEGF-A levels in the RPE/choroid after laser injury in wild-type (P < 0.05) but not P2rx7−/− mice. Moreover, there was no additive effect of 3TC on CNV inhibition when coadministered with a neutralizing VEGF-A antibody. Stimulation of human and mouse P2X7-expressing HEK293 cells with Bz-ATP increased VEGF secretion (P < 0.001), which was abrogated by 3TC (P < 0.001). Stimulation of primary human RPE cells with Bz-ATP increased VEGFA and IL6 mRNA levels, which were abrogated by 3TC. Conclusions Multiple clinically relevant NRTIs suppressed laser-induced CNV and downregulated VEGF-A, via P2X7. PMID:26529046

  13. Histone deacetylase inhibitors suppress RSV infection and alleviate virus-induced airway inflammation.

    PubMed

    Feng, Qiuqin; Su, Zhonglan; Song, Shiyu; Χu, Hui; Zhang, Bin; Yi, Long; Tian, Man; Wang, Hongwei

    2016-09-01

    Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants and young children. However, the majority of RSV-infected patients only show mild symptoms. Different severities of infection and responses among the RSV-infected population indicate that epigenetic regulation as well as personal genetic background may affect RSV infectivity. Histone deacetylase (HDAC) is an important epigenetic regulator in lung diseases. The present study aimed to explore the possible connection between HDAC expression and RSV-induced lung inflammation. To address this question, RSV-infected airway epithelial cells (BEAS‑2B) were prepared and a mouse model of RSV infection was established, and then treated with various concentrations of HDAC inhibitors (HDACis), namely trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA). Viral replication and markers of virus-induced airway inflammation or oxidative stress were assessed. The activation of the nuclear factor-κB (NF-κB), cyclo-oxygenase-2 (COX-2), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathways was evaluated by western blot analysis. Our results showed that RSV infection in airway epithelial cells (AECs) significantly decreased histone acetylation levels by altering HDAC2 expression. The treatment of RSV-infected AECs with HDACis significantly restricted RSV replication by upregulating the interferon-α (IFN-α) related signaling pathways. The treatment of RSV-infected AECs with HDACis also significantly inhibited RSV-induced pro-inflammatory cytokine release [interleukin (IL)-6 and IL-8] and oxidative stress-related molecule production [malondialdehyde (MDA), and nitrogen monoxide (NO)]. The activation of NF-κB, COX-2, MAPK and Stat3, which orchestrate pro‑inflammatory gene expression and oxidative stress injury, was also significantly inhibited. Our in vivo study using a mouse model of

  14. Histone deacetylase inhibitors suppress RSV infection and alleviate virus-induced airway inflammation

    PubMed Central

    Feng, Qiuqin; Su, Zhonglan; Song, Shiyu; Xu, Hui; Zhang, Bin; Yi, Long; Tian, Man; Wang, Hongwei

    2016-01-01

    Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants and young children. However, the majority of RSV-infected patients only show mild symptoms. Different severities of infection and responses among the RSV-infected population indicate that epigenetic regulation as well as personal genetic background may affect RSV infectivity. Histone deacetylase (HDAC) is an important epigenetic regulator in lung diseases. The present study aimed to explore the possible connection between HDAC expression and RSV-induced lung inflammation. To address this question, RSV-infected airway epithelial cells (BEAS-2B) were prepared and a mouse model of RSV infection was established, and then treated with various concentrations of HDAC inhibitors (HDACis), namely trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA). Viral replication and markers of virus-induced airway inflammation or oxidative stress were assessed. The activation of the nuclear factor-κB (NF-κB), cyclo-oxygenase-2 (COX-2), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathways was evaluated by western blot analysis. Our results showed that RSV infection in airway epithelial cells (AECs) significantly decreased histone acetylation levels by altering HDAC2 expression. The treatment of RSV-infected AECs with HDACis significantly restricted RSV replication by upregulating the interferon-α (IFN-α) related signaling pathways. The treatment of RSV-infected AECs with HDACis also significantly inhibited RSV-induced pro-inflammatory cytokine release [interleukin (IL)-6 and IL-8] and oxidative stress-related molecule production [malondialdehyde (MDA), and nitrogen monoxide (NO)]. The activation of NF-κB, COX-2, MAPK and Stat3, which orchestrate pro-inflammatory gene expression and oxidative stress injury, was also significantly inhibited. Our in vivo study using a mouse model of RSV infection

  15. 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.

  16. 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

  17. Application of Site-Specific Spin Labeling for NMR Detecting Inhibitor-Induced Conformational Change of HIV-1 Reverse Transcriptase.

    PubMed

    Seetaha, Supaporn; Yagi-Utsumi, Maho; Yamaguchi, Takumi; Ishii, Kentaro; Hannongbua, Supa; Choowongkomon, Kiattawee; Kato, Koichi

    2016-02-17

    Paramagnetism-assisted nuclear magnetic resonance (NMR) techniques can provide long-range structural information complemented with local information derived from chemical-shift perturbation and nuclear Overhauser effect data. Here, we address the application of paramagnetic relaxation enhancement (PRE) to detect inhibitor-induced conformational change of a drug target protein using human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) as a model protein. Using a site-specific spin-labeled HIV-1 RT mutant with selective (13) C labeling, conformation-dependent PREs were successfully observed reflecting the stabilization of an open conformation of this enzyme caused by inhibitor binding. This study demonstrates that the paramagnetism-assisted NMR approach offers an alternative strategy in protein-based drug screening to identify allosteric inhibitors of a target protein. PMID:26804978

  18. Peroxisome proliferators alter the expression of estrogen-metabolizing enzymes.

    PubMed

    Corton, J C; Bocos, C; Moreno, E S; Merritt, A; Cattley, R C; Gustafsson, J A

    1997-01-01

    Exposure to some peroxisome proliferator chemicals (PPC) leads to toxic effects on sex organ function possibly by alterations of steroid hormone metabolism. A systematic search for genes whose mRNA levels are modulated by the PPC WY-14643 (WY) was carried out in rat liver, a site of steroid hormone metabolism. The sequence of one up-regulated cDNA (2480 bp) was predicted to encode a protein of 735 amino acids with 82% identity to the porcine 17 beta-hydroxysteroid dehydrogenase type IV (HSD IV) originally isolated as a 17 beta-estradiol dehydrogenase. The rat HSD IV was localized to peroxisomes and was regulated by diverse PPC by two distinct mechanisms. Induction of HSD IV and acyl-CoA oxidase (ACO) proteins in rat liver at different treatment times and concentrations of gemfibrozil (GEM) and di-n-butyl phthalate (DBP) were almost identical, suggesting that HSD IV mRNA induction involves the peroxisome proliferator-activated receptor alpha, a regulator of ACO. In contrast, HSD IV protein levels were only weakly induced by WY, a strong inducer of ACO protein, even though the levels of both HSD IV and ACO mRNA were strongly stimulated by WY. Thus HSD IV protein levels were uniquely regulated pretranslationally by WY. In addition to HSD IV we also identified the male-specific alpha 2u-globulin as a PPC down-regulated gene. This prompted us to examine the expression of another male-specific gene, CYP2C11, that catalyzes the hydroxylations of estradiol at the 2 and 16 alpha positions. Cyp2C11 protein expression in rat liver was either decreased or completely abolished after a 3-week treatment by GEM or WY, respectively. Decreased expression of enzymes which inactivate estradiol including Cyp2C11, and the reported increased expression of aromatase may explain why male rats exposed to diverse PPC have higher serum estradiol levels. These higher estradiol levels in male rats have been thought to be mechanistically linked to Leydig cell hyperplasia and adenomas. Increased

  19. Peroxisomal Localization and Circadian Regulation of Ubiquitin-Specific Protease 2

    PubMed Central

    Molusky, Matthew M.; Ma, Di; Buelow, Katie; Yin, Lei; Lin, Jiandie D.

    2012-01-01

    Temporal regulation of nutrient and energy metabolism is emerging as an important aspect of metabolic homeostasis. The regulatory network that integrates the timing cues and nutritional signals to drive diurnal metabolic rhythms remains poorly defined. The 45-kDa isoform of ubiquitin-specific protease 2 (USP2-45) is a deubiquitinase that regulates hepatic gluconeogenesis and glucose metabolism. In this study, we found that USP2-45 is localized to peroxisomes in hepatocytes through a canonical peroxisome-targeting motif at its C-terminus. Clustering analysis indicates that the expression of a subset of peroxisomal genes exhibits robust diurnal rhythm in the liver. Despite this, nuclear hormone receptor PPARα, a known regulator of peroxisome gene expression, does not induce USP2-45 in hepatocytes and is dispensible for its expression during starvation. In contrast, a functional liver clock is required for the proper nutritional and circadian regulation of USP2-45 expression. At the molecular level, transcriptional coactivators PGC-1α and PGC-1β and repressor E4BP4 exert opposing effects on USP2-45 promoter activity. These studies provide insights into the subcellular localization and transcriptional regulation of a clock-controlled deubiquitinase that regulates glucose metabolism. PMID:23133608

  20. Peroxisomal localization and circadian regulation of ubiquitin-specific protease 2.

    PubMed

    Molusky, Matthew M; Ma, Di; Buelow, Katie; Yin, Lei; Lin, Jiandie D

    2012-01-01

    Temporal regulation of nutrient and energy metabolism is emerging as an important aspect of metabolic homeostasis. The regulatory network that integrates the timing cues and nutritional signals to drive diurnal metabolic rhythms remains poorly defined. The 45-kDa isoform of ubiquitin-specific protease 2 (USP2-45) is a deubiquitinase that regulates hepatic gluconeogenesis and glucose metabolism. In this study, we found that USP2-45 is localized to peroxisomes in hepatocytes through a canonical peroxisome-targeting motif at its C-terminus. Clustering analysis indicates that the expression of a subset of peroxisomal genes exhibits robust diurnal rhythm in the liver. Despite this, nuclear hormone receptor PPARα, a known regulator of peroxisome gene expression, does not induce USP2-45 in hepatocytes and is dispensible for its expression during starvation. In contrast, a functional liver clock is required for the proper nutritional and circadian regulation of USP2-45 expression. At the molecular level, transcriptional coactivators PGC-1α and PGC-1β and repressor E4BP4 exert opposing effects on USP2-45 promoter activity. These studies provide insights into the subcellular localization and transcriptional regulation of a clock-controlled deubiquitinase that regulates glucose metabolism. PMID:23133608

  1. Peroxisome Proliferator-Activated Receptor Ligands and Their Role in Chronic Myeloid Leukemia: Therapeutic Strategies.

    PubMed

    Yousefi, Bahman; Samadi, Nasser; Baradaran, Behzad; Shafiei-Irannejad, Vahid; Zarghami, Nosratollah

    2016-07-01

    Imatinib therapy remains the gold standard for treatment of chronic myeloid leukemia; however, the acquired resistance to this therapeutic agent in patients has urged the scientists to devise modalities for overcoming this chemoresistance. For this purpose, initially therapeutic agents with higher tyrosine kinase activity were introduced, which had the potential for inhibiting even mutant forms of Bcr-Abl. Furthermore, coupling imatinib with peroxisome proliferator-activated receptor ligands also showed beneficial effects in chronic myeloid leukemia cell proliferation. These combination protocols inhibited cell growth and induced apoptosis as well as differentiation in chronic myeloid leukemia cell lines. In addition, peroxisome proliferator-activated receptors ligands increased imatinib uptake by upregulating the expression of human organic cation transporter 1. Taken together, peroxisome proliferator-activated receptors ligands are currently being considered as novel promising therapeutic candidates for chronic myeloid leukemia treatment, because they can synergistically enhance the efficacy of imatinib. In this article, we reviewed the potential of peroxisome proliferator-activated receptors ligands for use in chronic myeloid leukemia treatment. The mechanism of action of these therapeutics modalities are also presented in detail. PMID:26841308

  2. Towards repurposing the yeast peroxisome for compartmentalizing heterologous metabolic pathways

    DOE PAGESBeta

    DeLoache, William C.; Russ, Zachary N.; Dueber, John E.

    2016-03-30

    Compartmentalization of enzymes into organelles is a promising strategy for limiting metabolic crosstalk and improving pathway efficiency, but improved tools and design rules are needed to make this strategy available to more engineered pathways. Here we focus on the Saccharomyces cerevisiae peroxisome and develop a sensitive high-throughput assay for peroxisomal cargo import. We identify an enhanced peroxisomal targeting signal type 1 (PTS1) for rapidly sequestering non-native cargo proteins. Additionally, we perform the first systematic in vivo measurements of nonspecific metabolite permeability across the peroxisomal membrane using a polymer exclusion assay. Finally, we apply these new insights to compartmentalize a two-enzymemore » pathway in the peroxisome and characterize the expression regimes where compartmentalization leads to improved product titre. Lastly, this work builds a foundation for using the peroxisome as a synthetic organelle, highlighting both promise and future challenges on the way to realizing this goal.« less

  3. [Possible participation of mitochondria in formation of peroxisomes in yeasts].

    PubMed

    Kozlova, T M; Meĭsel', 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

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