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Yoon SB, Choi SA, Sim BW, Kim JS, Mun SE, Jeong PS, Yang HJ, Lee Y, Park YH, Song BS, Kim YH, Jeong KJ, Huh JW, Lee SR, Kim SU, Chang KT. Developmental competence of bovine early embryos depends on the coupled response between oxidative and endoplasmic reticulum stress. Biol Reprod 2014; 90:104. [PMID: 24695629 DOI: 10.1095/biolreprod.113.113480] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The stress produced by the coupling of reactive oxygen species (ROS) and endoplasmic reticulum (ER) has been explored extensively, but little is known regarding their roles in the early development of mammalian embryos. Here, we demonstrated that the early development of in vitro-produced (IVP) bovine embryos was governed by the cooperative action between ROS and ER stress. Compared with the tension produced by 5% O2, 20% O2 significantly decreased the blastocyst formation rate and cell survival, which was accompanied by increases in ROS and in levels of sXBP-1 transcript, which is an ER stress indicator. In addition, treatment with glutathione (GSH), a ROS scavenger, decreased ROS levels, which resulted in increased blastocyst formation and cell survival rates. Importantly, levels of sXBP-1 and ER stress-associated transcripts were reduced by GSH treatment in developing bovine embryos. Consistent with this observation, tauroursodeoxycholate (TUDCA), an ER stress inhibitor, improved blastocyst developmental rate, trophectoderm proportion, and cell survival. Moreover, ROS and sXBP-1 transcript levels were markedly decreased by supplementation with TUDCA, suggesting a possible mechanism governing the mutual regulation between ROS and ER stress. Interestingly, knockdown of XBP-1 transcripts resulted in both elevation of ROS and decrease of antioxidant transcripts, which ultimately reduced in vitro developmental competence of bovine embryos. Based on these results, in vitro developmental competence of IVP bovine embryos was highly dependent on the coupled response between oxidative and ER stresses. These results increase our understanding of the mechanism(s) governing early embryonic development and may improve strategies for the generation of IVP embryos with high developmental competence.
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Affiliation(s)
- Seung-Bin Yoon
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea
| | - Seon-A Choi
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Bo-Woong Sim
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Ji-Su Kim
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Seong-Eun Mun
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Pil-Soo Jeong
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Hae-Jun Yang
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Youngjeon Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Young-Ho Park
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Bong-Seok Song
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Young-Hyun Kim
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Kang-Jin Jeong
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea
| | - Jae-Won Huh
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea
| | - Sang-Rae Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea
| | - Sun-Uk Kim
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea
| | - Kyu-Tae Chang
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, Republic of Korea Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea
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152
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Hepatic steatosis exacerbated by endoplasmic reticulum stress-mediated downregulation of FXR in aging mice. J Hepatol 2014; 60:847-54. [PMID: 24333182 DOI: 10.1016/j.jhep.2013.12.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/12/2013] [Accepted: 12/02/2013] [Indexed: 01/06/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic fatty liver disease (NAFLD) is characterized by an increase in hepatic triglyceride (TG) contents. The prevalence of NAFLD is increased with aging. However, the molecular mechanism for aging-induced fatty liver remains poorly understood. METHODS Hepatic TG contents and gene expression profiles were analyzed in body weight-matched young (2 months), middle (8 months) and old (18 months) C57BL/6 mice. Endoplasmic reticulum (ER) stress and farnesoid X receptor (FXR) expression were examined. The mechanism of ER stress activation in the regulation of FXR expression was further investigated. RESULTS In the present study, we found that TG was markedly accumulated and lipogenic genes were up-regulated in the liver of C57BL/6 mice aged 18 months. FXR, a key regulator of hepatic lipid metabolism was down-regulated in these old mice. At molecular levels, ER stress was activated in old mice and repressed FXR expression through inhibition of hepatocyte nuclear factor 1 alpha (HNF1α) transcriptional activity. CONCLUSIONS Our findings demonstrate that FXR down-regulation plays a critical role in aging-induced fatty liver.
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153
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Cha BH, Kim JS, Ahn JC, Kim HC, Kim BS, Han DK, Park SG, Lee SH. The role of tauroursodeoxycholic acid on adipogenesis of human adipose-derived stem cells by modulation of ER stress. Biomaterials 2014; 35:2851-8. [PMID: 24424209 DOI: 10.1016/j.biomaterials.2013.12.067] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/20/2013] [Indexed: 01/06/2023]
Abstract
Obesity has become a serious public health problem in the developed world. Increased mass of adipose tissue in the obese is due to an increase in both the size (hypertrophy) and number (hyperplasia) of adipocytes. The chemical chaperone tauroursodeoxycholic acid (TUDCA) not only decreases endoplasmic reticulum (ER) stress, but also plays a role as a leptin-sensitizing agent for preadipocytes in mice and humans. In this study, we examine whether TUDCA has an effect on adipogenesis from human adipose-derived stem cells (hASCs). Therefore, the effect of TUDCA on ER stress, lipid accumulation, and adipogenic differentiation from hASCs was investigated using histological staining, reverse-transcriptase polymerase chain reaction (RT-PCR), and western blotting in vitro. It was found that TUDCA treatment of hASCs significantly decreases the representative ER stress marker (glucose-regulated protein 78 kDa (GRP78)), adipogenic markers (peroxisome proliferator-activated receptor gamma (PPARγ) and glycerol-3-phosphate dehydrogenase 1 (GPDH)), and lipid accumulation. Furthermore, we confirmed that TUDCA treatment of hASCs significantly decreased in vivo adipogenic tissue formation and ER stress comparing with PBS treatment of hASCs. The results indicate that TUDCA plays a critical role in adipogenesis from hASCs by modulating ER stress and, therefore, has potential pharmacologic and therapeutic applications as an anti-obesity agent.
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Affiliation(s)
- Byung-Hyun Cha
- Department of Biomedical Science, College of Life Science, CHA University, Yatap-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 463-840, Republic of Korea
| | - Jin-Su Kim
- Department of Biomedical Science, College of Life Science, CHA University, Yatap-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 463-840, Republic of Korea
| | - Jong Chan Ahn
- Department of Biomedical Science, College of Life Science, CHA University, Yatap-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 463-840, Republic of Korea
| | - Hee-Chun Kim
- Department of Orthopaedics, Bundang CHA Hospital, Sungnam, Republic of Korea
| | - Byung-Soo Kim
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea
| | - Dong Keun Han
- Center for Biomaterials, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Republic of Korea
| | - Sang Gyu Park
- Department of Biomedical Science, College of Life Science, CHA University, Yatap-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 463-840, Republic of Korea
| | - Soo-Hong Lee
- Department of Biomedical Science, College of Life Science, CHA University, Yatap-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 463-840, Republic of Korea.
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154
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Lipid overloading during liver regeneration causes delayed hepatocyte DNA replication by increasing ER stress in mice with simple hepatic steatosis. J Gastroenterol 2014; 49:305-16. [PMID: 23512345 PMCID: PMC3925298 DOI: 10.1007/s00535-013-0780-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/11/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIM Impaired fatty liver regeneration has already been reported in many genetic modification models. However, in diet-induced simple hepatic steatosis, which showed similar phenotype with clinical pathology, whether liver regeneration is impaired or not remains unclear. In this study, we evaluated liver regeneration in mice with diet-induced simple hepatic steatosis, and focused on excess lipid accumulation occurring during liver regeneration. METHODS Mice were fed high fat diet (HFD) or control diet for 9-10 weeks. We analyzed intrahepatic lipid accumulation, DNA replication, and various signaling pathways including cell proliferation and ER stress during liver regeneration after partial hepatectomy. In addition, some of mice were pretreated with tauroursodeoxycholic acid (TUDCA), a chemical chaperone which alleviates ER stress, and then we estimated TUDCA effects on liver regeneration. RESULTS The peak of hepatocyte BrdU incorporation, the expression of proliferation cell nuclear antigen (PCNA) protein, and the expressions of cell cycle-related genes were observed in delayed time in HFD mice. The expression of phosphorylated Erk1/2 was also delayed in HFD mice. The amounts of liver triglyceride were at least twofold higher in HFD mice at each time point. Intrahepatic palmitic acid was increased especially in HFD mice. ER stress induced during liver regeneration was significantly higher in HFD mice. In HFD mice, pretreatment with TUDCA reduced ER stress and resulted in improvement of delayed liver regeneration. CONCLUSION In simple hepatic steatosis, lipid overloading occurring during liver regeneration might be caused ER stress and results in delayed hepatocyte DNA replication.
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155
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Komita M, Jin H, Aoe T. The Effect of Endoplasmic Reticulum Stress on Neurotoxicity Caused by Inhaled Anesthetics. Anesth Analg 2013; 117:1197-204. [DOI: 10.1213/ane.0b013e3182a74773] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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156
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Abstract
The unfolded protein response (UPR) is a protective cellular response activated under conditions of endoplasmic reticulum (ER) stress. The hepatic UPR is activated in several forms of liver disease including nonalcoholic fatty liver disease (NAFLD). Recent data defining the role of the UPR in hepatic lipid metabolism have identified molecular mechanisms that may underlie the association between UPR activation and NAFLD. It has become increasingly evident that the IRE1α/Xbp1 pathway of the UPR is critical for hepatic lipid homeostasis, and dysregulation of this evolutionarily conserved pathway is associated with human nonalcoholic steatohepatitis (NASH). Although increasing evidence has delineated the importance of UPR pathway signaling in fatty liver disorders, the regulation of the hepatic UPR in normal physiology and fatty liver disorders remains incompletely understood. Understanding the role of the UPR in hepatic lipid metabolism may lead to the identification of novel therapeutic targets for the treatment of NAFLD.
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Affiliation(s)
- Anne Henkel
- Assistant Professor of Medicine, Division of Gastroenterology and Hepatology, Section of Hepatology, Northwestern University Feinberg School of Medicine, Tarry Building 15-705, 303 East Chicago Avenue, Chicago, IL 60611, Tel: 312-503-3148, Fax: 312-908-9032
| | - Richard M. Green
- Professor of Medicine, Division of Gastroenterology and Hepatology, Section of Hepatology, Northwestern University Feinberg School of Medicine, Tarry Building 15-719, 303 East Chicago Avenue, Chicago, IL 60611, Tel: 312-503-1812, Fax: 312-908-9032
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157
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Buryova H, Chalupsky K, Zbodakova O, Kanchev I, Jirouskova M, Gregor M, Sedlacek R. Liver protective effect of ursodeoxycholic acid includes regulation of ADAM17 activity. BMC Gastroenterol 2013; 13:155. [PMID: 24172289 PMCID: PMC3835136 DOI: 10.1186/1471-230x-13-155] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/18/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Ursodeoxycholic acid (UDCA) is used to treat primary biliary cirrhosis, intrahepatic cholestasis, and other cholestatic conditions. Although much has been learned about the molecular basis of the disease pathophysiology, our understanding of the effects of UDCA remains unclear. Possibly underlying its cytoprotective, anti-apoptotic, anti-oxidative effects, UDCA was reported to regulate the expression of TNFα and other inflammatory cytokines. However, it is not known if this effect involves also modulation of ADAM family of metalloproteinases, which are responsible for release of ectodomains of inflammatory cytokines from the cell surface. We hypothesized that UDCA modulates ADAM17 activity, resulting in amelioration of cholestasis in a murine model of bile duct ligation (BDL). METHODS The effect of UDCA on ADAM17 activity was studied using the human liver hepatocellular carcinoma cell line HepG2. Untransfected cells or cells ectopically expressing human ADAM17 were cultured with or without UDCA and further activated using phorbol-12-myristate-13-acetate (PMA). The expression and release of ADAM17 substrates, TNFα, TGFα, and c-Met receptor (or its soluble form, sMet) were evaluated using ELISA and quantitative real-time (qRT) PCR. Immunoblotting analyses were conducted to evaluate expression and activation of ADAM17 as well as the level of ERK1/2 phosphorylation after UDCA treatment. The regulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) by UDCA was studied using zymography and qRT-PCR. A mouse model of acute cholestasis was induced by common BDL technique, during which mice received daily orogastric gavage with either UDCA or vehicle only. Liver injury was quantified using alkaline phosphatase (ALP), relative liver weight, and confirmed by histological analysis. ADAM17 substrates in sera were assessed using a bead multiplex assay. RESULTS UDCA decreases amount of shed TNFα, TGFα, and sMet in cell culture media and the phosphorylation of ERK1/2. These effects are mediated by the reduction of ADAM17 activity in PMA stimulated cells although the expression ADAM17 is not affected. UDCA reduced the level of the mature form of ADAM17. Moreover, UDCA regulates the expression of TIMP-1 and gelatinases activity in PMA stimulated cells. A BDL-induced acute cholangitis model was characterized by increased relative liver weight, serum levels of ALP, sMet, and loss of intracellular glycogen. UDCA administration significantly decreased ALP and sMet levels, and reduced relative liver weight. Furthermore, hepatocytes of UDCA-treated animals retained their metabolic activity as evidenced by the amount of glycogen storage. CONCLUSIONS The beneficial effect of UDCA appears to be mediated in part by the inhibition of ADAM17 activation and, thus, the release of TNFα, a strong pro-inflammatory factor. The release of other ADAM17 substrates, TGFα and sMet, are also regulated this way, pointing to a general impact on the release of ADAM17 substrates, which are pivotal for liver regeneration and function. In parallel, UDCA upregulates TIMP-1 that in turn inhibits matrix metalloproteinases, which destroy the hepatic ECM in diseased liver. This control of extracellular matrix turnover represents an additional beneficial path of UDCA treatment.
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Affiliation(s)
| | | | | | | | | | | | - Radislav Sedlacek
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the ASCR, v, v, i,, Videnska 1083, Prague CZ142 20, Czech Republic.
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158
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Gaspar JM, Martins A, Cruz R, Rodrigues CMP, Ambrósio AF, Santiago AR. Tauroursodeoxycholic acid protects retinal neural cells from cell death induced by prolonged exposure to elevated glucose. Neuroscience 2013; 253:380-8. [PMID: 24012838 DOI: 10.1016/j.neuroscience.2013.08.053] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/25/2013] [Accepted: 08/27/2013] [Indexed: 11/28/2022]
Abstract
Diabetic retinopathy is one of the most frequent causes of blindness in adults in the Western countries. Although diabetic retinopathy is considered a vascular disease, several reports demonstrate that retinal neurons are also affected, leading to vision loss. Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, has proven to be neuroprotective in several models of neurodegenerative diseases, including models of retinal degeneration. Since hyperglycemia is considered to play a central role in retinal cell dysfunction and degeneration, underlying the progression of diabetic retinopathy, the purpose of this study was to investigate the neuroprotective effects of TUDCA in rat retinal neurons exposed to elevated glucose concentration. We found that TUDCA markedly decreased cell death in cultured retinal neural cells induced by exposure to elevated glucose concentration. In addition, TUDCA partially prevented the release of apoptosis-inducing factor (AIF) from the mitochondria, as well as the subsequent accumulation of AIF in the nucleus. Biomarkers of oxidative stress, such as protein carbonyl groups and reactive oxygen species production, were markedly decreased after TUDCA treatment as compared to cells exposed to elevated glucose concentration alone. In conclusion, TUDCA protected retinal neural cell cultures from cell death induced by elevated glucose concentration, decreasing mito-nuclear translocation of AIF. The antioxidant properties of TUDCA might explain its cytoprotection. These findings may have relevance in the treatment of diabetic retinopathy patients.
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Affiliation(s)
- J M Gaspar
- Center of Ophthalmology and Vision Sciences, Institute of Biomedical Research in Light and Image (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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159
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Sphingosine kinase-1 inhibition protects primary rat hepatocytes against bile salt-induced apoptosis. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1922-9. [PMID: 23816565 DOI: 10.1016/j.bbadis.2013.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 05/10/2013] [Accepted: 06/19/2013] [Indexed: 01/22/2023]
Abstract
Sphingosine kinases (SphKs) and their product sphingosine-1-phosphate (S1P) have been reported to regulate apoptosis and survival of liver cells. Cholestatic liver diseases are characterized by cytotoxic levels of bile salts inducing liver injury. It is unknown whether SphKs and/or S1P play a role in this pathogenic process. Here, we investigated the putative involvement of SphK1 and S1P in bile salt-induced cell death in hepatocytes. Primary rat hepatocytes were exposed to glycochenodeoxycholic acid (GCDCA) to induce apoptosis. GCDCA-exposed hepatocytes were co-treated with S1P, the SphK1 inhibitor Ski-II and/or specific antagonists of S1P receptors (S1PR1 and S1PR2). Apoptosis and necrosis were quantified. Ski-II significantly reduced GCDCA-induced apoptosis in hepatocytes (-70%, P<0.05) without inducing necrosis. GCDCA increased the S1P levels in hepatocytes (P<0.05). GCDCA induced [Ca(2+)] oscillations in hepatocytes and co-treatment with the [Ca(2+)] chelator BAPTA repressed GCDCA-induced apoptosis. Ski-II inhibited the GCDCA-induced intracellular [Ca(2+)] oscillations. Transcripts of all five S1P receptors were detected in hepatocytes, of which S1PR1 and S1PR2 appear most dominant. Inhibition of S1PR1, but not S1PR2, reduced GCDCA-induced apoptosis by 20%. Exogenous S1P also significantly reduced GCDCA-induced apoptosis (-50%, P<0.05), however, in contrast to the GCDCA-induced (intracellular) SphK1 pathway, this was dependent on S1PR2 and not S1PR1. Our results indicate that SphK1 plays a pivotal role in mediating bile salt-induced apoptosis in hepatocytes in part by interfering with intracellular [Ca(2+)] signaling and activation of S1PR1.
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160
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Ahn JC, Biswas R, Moon JH, Chung PS. Cellular uptake of 9-hydroxypheophorbide-α and its photoactivation to induce ER stress-related apoptosis in human cervical cancer cells. Lasers Med Sci 2013; 29:289-99. [DOI: 10.1007/s10103-013-1331-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/16/2013] [Indexed: 10/26/2022]
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161
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Turdi S, Hu N, Ren J. Tauroursodeoxycholic acid mitigates high fat diet-induced cardiomyocyte contractile and intracellular Ca2+ anomalies. PLoS One 2013; 8:e63615. [PMID: 23667647 PMCID: PMC3647067 DOI: 10.1371/journal.pone.0063615] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 04/09/2013] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES The endoplasmic reticulum (ER) chaperone tauroursodeoxycholic acid (TUDCA) has exhibited promises in the treatment of obesity, although its impact on obesity-induced cardiac dysfunction is unknown. This study examined the effect of TUDCA on cardiomyocyte function in high-fat diet-induced obesity. METHODS Adult mice were fed low or high fat diet for 5 months prior to treatment of TUDCA (300 mg/kg. i.p., for 15d). Intraperitoneal glucose tolerance test (IPGTT), cardiomyocyte mechanical and intracellular Ca(2+) property, insulin signaling molecules including IRS-1, Akt, AMPK, ACC, GSK-3β, c-Jun, ERK and c-Jun N terminal kinase (JNK) as well as ER stress and intracellular Ca(2+) regulatory proteins were examined. Myocardial ultrastructure was evaluated using transmission electron microscopy (TEM). RESULTS High-fat diet depressed peak shortening (PS) and maximal velocity of shortening/relengthenin as well as prolonged relengthening duration. TUDCA reversed or overtly ameliorated high fat diet-induced cardiomyocyte dysfunction including prolongation in relengthening. TUDCA alleviated high-fat diet-induced decrease in SERCA2a and phosphorylation of phospholamban, increase in ER stress (GRP78/BiP, CHOP, phosphorylation of PERK, IRE1α and eIF2α), ultrastructural changes and mitochondrial permeation pore opening. High-fat diet feeding inhibited phosphorylation of AMPK and promoted phosphorylation of GSK-3β. TUDCA prevented high fat-induced dephosphorylation of AMPK but not GSK-3β. High fat diet promoted phosphorylation of IRS-1 (Ser(307)), JNK, and ERK without affecting c-Jun phosphorylation, the effect of which with the exception of ERK phosphorylation was attenuated by TUDCA. CONCLUSIONS These data depict that TUDCA may ameliorate high fat diet feeding-induced cardiomyocyte contractile and intracellular Ca(2+) defects through mechanisms associated with mitochondrial integrity, AMPK, JNK and IRS-1 serine phosphorylation.
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Affiliation(s)
- Subat Turdi
- Center for Cardiovascular Research and Alternative Medicine, Division of Pharmaceutical Sciences, University of Wyoming College of Health Sciences, Laramie, Wyoming, United States of America
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162
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Transport and biological activities of bile acids. Int J Biochem Cell Biol 2013; 45:1389-98. [PMID: 23603607 DOI: 10.1016/j.biocel.2013.04.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/30/2013] [Accepted: 04/09/2013] [Indexed: 12/29/2022]
Abstract
Bile acids have emerged as important biological molecules that support the solubilization of various lipids and lipid-soluble compounds in the gut, and the regulation of gene expression and cellular function. Bile acids are synthesized from cholesterol in the liver and eventually released into the small intestine. The majority of bile acids are recovered in the distal end of the small intestine and then returned to the liver for reuse. The components of the mechanism responsible for the recycling of bile acids within the enterohepatic circulation have been identified whereas the mechanism for intracellular transport is less understood. Recently, the ileal lipid binding protein (ILBP; human gene symbol FABP6) was shown to be needed for the efficient transport of bile acids from the apical side to the basolateral side of enterocytes in the distal intestine. This review presents an overview of the transport of bile acids between the liver and the gut as well as within hepatocytes and enterocytes. A variety of pathologies is associated with the malfunction of the bile acid transport system.
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163
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Park SJ, Kim TS, Park CK, Lee SH, Kim JM, Lee KS, Lee IK, Park JW, Lawson MA, Lee DS. hCG-induced endoplasmic reticulum stress triggers apoptosis and reduces steroidogenic enzyme expression through activating transcription factor 6 in Leydig cells of the testis. J Mol Endocrinol 2013; 50:151-66. [PMID: 23256993 PMCID: PMC4111658 DOI: 10.1530/jme-12-0195] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Endoplasmic reticulum (ER) stress generally occurs in secretory cell types. It has been reported that Leydig cells, which produce testosterone in response to human chorionic gonadotropin (hCG), express key steroidogenic enzymes for the regulation of testosterone synthesis. In this study, we analyzed whether hCG induces ER stress via three unfolded protein response (UPR) pathways in mouse Leydig tumor (mLTC-1) cells and the testis. Treatment with hCG induced ER stress in mLTC-1 cells via the ATF6, IRE1a/XBP1, and eIF2α/GADD34/ATF4 UPR pathways, and transient expression of 50 kDa protein activating transcription factor 6 (p50ATF6) reduced the expression level of steroidogenic 3β-hydroxysteroid dehydrogenase Δ5-Δ4-isomerase (3β-HSD) enzyme. In an in vivo model, high-level hCG treatment induced expression of p50ATF6 while that of steroidogenic enzymes, especially 3β-HSD, 17α-hydroxylase/C17-20 lyase (CYP17), and 17β-hydrozysteroid dehydrogenase (17β-HSD), was reduced. Expression levels of steroidogenic enzymes were restored by the ER stress inhibitor tauroursodeoxycholic acid (TUDCA). Furthermore, lentivirus-mediated transient expression of p50ATF6 reduced the expression level of 3β-HSD in the testis. Protein expression levels of phospho-JNK, CHOP, and cleaved caspases-12 and -3 as markers of ER stress-mediated apoptosis markedly increased in response to high-level hCG treatment in mLTC-1 cells and the testis. Based on transmission electron microscopy and H&E staining of the testis, it was shown that abnormal ER morphology and destruction of testicular histology induced by high-level hCG treatment were reversed by the addition of TUDCA. These findings suggest that hCG-induced ER stress plays important roles in steroidogenic enzyme expression via modulation of the ATF6 pathway as well as ER stress-mediated apoptosis in Leydig cells.
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Affiliation(s)
- Sun-Ji Park
- Center for Food and Nutritional Genomics Research, Kyungpook National University, Daegu, Republic of Korea
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Sakabe T, Tsuchiya H, Kanki K, Azumi J, Gonda K, Mizuta Y, Yamada D, Wada H, Shomori K, Nagano H, Shiota G. Identification of the genes chemosensitizing hepatocellular carcinoma cells to interferon-α/5-fluorouracil and their clinical significance. PLoS One 2013; 8:e56197. [PMID: 23457527 PMCID: PMC3574150 DOI: 10.1371/journal.pone.0056197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 01/07/2013] [Indexed: 12/20/2022] Open
Abstract
The incidence of advanced hepatocellular carcinoma (HCC) is increasing worldwide, and its prognosis is extremely poor. Interferon-alpha (IFN-α)/5-fluorouracil (5-FU) therapy is reportedly effective in some HCC patients. In the present study, to improve HCC prognosis, we identified the genes that are sensitizing to these agents. The screening strategy was dependent on the concentration of ribozymes that rendered HepG2 cells resistant to 5-FU by the repeated transfection of ribozymes into the cells. After 10 cycles of transfection, which was initiated by 5,902,875 sequences of a ribozyme library, three genes including protein kinase, adenosine monophosphate (AMP)-activated, gamma 2 non-catalytic subunit (PRKAG2); transforming growth factor-beta receptor II (TGFBR2); and exostosin 1 (EXT1) were identified as 5-FU-sensitizing genes. Adenovirus-mediated transfer of TGFBR2 and EXT1 enhanced IFN-α/5-FU-induced cytotoxicity as well as 5-FU, although the overexpression of these genes in the absence of IFN-α/5-FU did not induce cell death. This effect was also observed in a tumor xenograft model. The mechanisms of TGFBR2 and EXT1 include activation of the TGF-β signal and induction of endoplasmic reticulum stress, resulting in apoptosis. In HCC patients treated with IFN-α/5-FU therapy, the PRKAG2 mRNA level in HCC tissues was positively correlated with survival period, suggesting that PRKAG2 enhances the effect of IFN-α/5-FU and serves as a prognostic marker for IFN-α/5-FU therapy. In conclusion, we identified three genes that chemosensitize the effects of 5-FU and IFN-α/5-FU on HCC cells and demonstrated that PRKAG2 mRNA can serve as a prognostic marker for IFN-α/5-FU therapy.
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Affiliation(s)
- Tomohiko Sakabe
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
| | - Hiroyuki Tsuchiya
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Keita Kanki
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
| | - Junya Azumi
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
| | - Kazue Gonda
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
| | - Yusuke Mizuta
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
| | - Daisaku Yamada
- Department of Surgery, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Hiroshi Wada
- Department of Surgery, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Kohei Shomori
- Department of Microbiology and Pathology, Faculty of Medicine, Tottori University, Yonago, Japan
| | - Hiroaki Nagano
- Department of Surgery, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Goshi Shiota
- Division of Molecular and Genetic Medicine, Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medicine, Tottori University, Yonago, Japan
- * E-mail:
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165
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Tochigi M, Inoue T, Suzuki-Karasaki M, Ochiai T, Ra C, Suzuki-Karasaki Y. Hydrogen peroxide induces cell death in human TRAIL-resistant melanoma through intracellular superoxide generation. Int J Oncol 2013; 42:863-72. [PMID: 23314732 DOI: 10.3892/ijo.2013.1769] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 11/12/2012] [Indexed: 11/06/2022] Open
Abstract
Intracellular reactive oxygen species (ROS) such as hydrogen peroxide (H(2)O2()) are thought to mediate apoptosis induced by death receptor ligands, including tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). However, the role of H(2)O(2) is controversial, since some evidence suggests that H(2)O(2) acts as an anti-apoptotic factor. Here, we show that exogenously applied H(2)O(2) (30-100 µM) induces cell death in TRAIL-resistant human melanoma cells via intracellular superoxide (O(2)-) generation. H(2)O(2) induced apoptotic or necrotic cell death, depending on the concentration of the oxidant applied; low concentrations of H(2)O(2) preferentially activated the caspase-dependent apoptotic pathway, while high concentrations of H(2)O(2) induced apoptotic and necrotic cell death in a caspase-independent manner. The H(2)O(2)-induced cell death was associated with increased mitochondrial membrane potential collapse and caspase-3/7 activation and ER stress responses including caspase-12 and X-box-binding protein-1 (XBP-1) activation. H(2)O(2) induced intracellular O2- generation even within the mitochondria, while TRAIL did not. The superoxide dismutase mimetic antioxidant MnTBaP [Mn (III) tetrakis (4-benzonic acid) porphyrin chloride] inhibited the H(2)O(2)-induced O(2)- generation, apoptosis and XBP-1 and caspase-12 activation at comparable concentrations. Importantly, H(2)O(2) treatment caused minimal O(2)- generation and apoptosis in normal primary melanocytes. These data show that H(2)O(2) induces endoplasmic reticulum-associated cell death via intracellular O(2)- generation and that malignant melanoma cells are more susceptible than normal cells to this oxidative cell death. The findings suggest that H(2)O(2) has therapeutic potential in the treatment of TRAIL-resistant melanoma.
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Affiliation(s)
- Mizuki Tochigi
- Division of Molecular Cell Immunology and Allergology, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan
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166
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Karimian G, Buist-Homan M, Mikus B, Henning RH, Faber KN, Moshage H. Angiotensin II protects primary rat hepatocytes against bile salt-induced apoptosis. PLoS One 2012; 7:e52647. [PMID: 23300732 PMCID: PMC3530435 DOI: 10.1371/journal.pone.0052647] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 11/19/2012] [Indexed: 02/06/2023] Open
Abstract
Angiotensin II (AT-II) is a pro-fibrotic compound that acts via membrane-bound receptors (AT-1R/AT-2R) and thereby activates hepatic stellate cells (HSCs). AT-II receptor blockers (ARBs) are thus important candidates in the treatment of liver fibrosis. However, multiple case reports suggest that AT-1R blockers may induce hepatocyte injury. Therefore, we investigated the effect of AT-II and its receptor blockers on cytokine-, oxidative stress- and bile salt-induced cell death in hepatocytes. Primary rat hepatocytes were exposed to TNF-α/Actinomycin D, the ROS-generating agent menadione or the bile salts: glycochenodeoxycholic acid (GCDCA) and tauro-lithocholic acid-3 sulfate (TLCS), to induce apoptosis. AT-II (100 nmol/L) was added 10 minutes prior to the cell death-inducing agent. AT-1R antagonists (Sartans) and the AT-2R antagonist PD123319 were used at 1 µmol/L. Apoptosis (caspase-3 activity, acridine orange staining) and necrosis (Sytox green staining) were quantified. Expression of CHOP (marker for ER stress) and AT-II receptor mRNAs were quantified by Q-PCR. AT-II dose-dependently reduced GCDCA-induced apoptosis of hepatocytes (−50%, p<0.05) without inducing necrosis. In addition, AT-II reduced TLCS-induced apoptosis of hepatocytes (−50%, p<0.05). However, AT-II did not suppress TNF/Act-D and menadione-induced apoptosis. Only the AT-1R antagonists abolished the protective effect of AT-II against GCDCA-induced apoptosis. AT-II increased phosphorylation of ERK and a significant reversal of the protective effect of AT-II was observed when signaling kinases, including ERK, were inhibited. Moreover, AT-II prevented the GCDCA-induced expression of CHOP (the marker of the ER-mediated apoptosis).
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Affiliation(s)
- Golnar Karimian
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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167
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Schönthal AH. Endoplasmic reticulum stress: its role in disease and novel prospects for therapy. SCIENTIFICA 2012; 2012:857516. [PMID: 24278747 PMCID: PMC3820435 DOI: 10.6064/2012/857516] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/12/2012] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle required for lipid biosynthesis, calcium storage, and protein folding and processing. A number of physiological and pathological conditions, as well as a variety of pharmacological agents, are able to disturb proper ER function and thereby cause ER stress, which severely impairs protein folding and therefore poses the risk of proteotoxicity. Specific triggers for ER stress include, for example, particular intracellular alterations (e.g., calcium or redox imbalances), certain microenvironmental conditions (e.g., hypoglycemia, hypoxia, and acidosis), high-fat and high-sugar diet, a variety of natural compounds (e.g., thapsigargin, tunicamycin, and geldanamycin), and several prescription drugs (e.g., bortezomib/Velcade, celecoxib/Celebrex, and nelfinavir/Viracept). The cell reacts to ER stress by initiating a defensive process, called the unfolded protein response (UPR), which is comprised of cellular mechanisms aimed at adaptation and safeguarding cellular survival or, in cases of excessively severe stress, at initiation of apoptosis and elimination of the faulty cell. In recent years, this dichotomic stress response system has been linked to several human diseases, and efforts are underway to develop approaches to exploit ER stress mechanisms for therapy. For example, obesity and type 2 diabetes have been linked to ER stress-induced failure of insulin-producing pancreatic beta cells, and current research efforts are aimed at developing drugs that ameliorate cellular stress and thereby protect beta cell function. Other studies seek to pharmacologically aggravate chronic ER stress in cancer cells in order to enhance apoptosis and achieve tumor cell death. In the following, these principles will be presented and discussed.
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Affiliation(s)
- Axel H. Schönthal
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, HMR-405, Los Angeles, CA 90033, USA
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168
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Jiménez-Castro MB, Elias-Miro M, Mendes-Braz M, Lemoine A, Rimola A, Rodés J, Casillas-Ramírez A, Peralta C. Tauroursodeoxycholic acid affects PPARγ and TLR4 in Steatotic liver transplantation. Am J Transplant 2012; 12:3257-71. [PMID: 22994543 DOI: 10.1111/j.1600-6143.2012.04261.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Numerous steatotic livers are discarded for transplantation because of their poor tolerance to ischemia-reperfusion (I/R). We examined whether tauroursodeoxycholic acid (TUDCA), a known inhibitor of endoplasmic reticulum (ER) stress, protects steatotic and nonsteatotic liver grafts preserved during 6 h in University of Wisconsin (UW) solution and transplanted. The protective mechanisms of TUDCA were also examined. Neither unfolded protein response (UPR) induction nor ER stress was evidenced in steatotic and nonsteatotic liver grafts after 6 h in UW preservation solution. TUDCA only protected steatotic livers grafts and did so through a mechanism independent of ER stress. It reduced proliferator-activated receptor-γ (PPARγ) and damage. When PPARγ was activated, TUDCA did not reduce damage. TUDCA, which inhibited PPARγ, and the PPARγ antagonist treatment up-regulated toll-like receptor 4 (TLR4), specifically the TIR domain-containing adaptor inducing IFNβ (TRIF) pathway. TLR4 agonist treatment reduced damage in steatotic liver grafts. When TLR4 action was inhibited, PPARγ antagonists did not protect steatotic liver grafts. In conclusion, TUDCA reduced PPARγ and this in turn up-regulated the TLR4 pathway, thus protecting steatotic liver grafts. TLR4 activating-based strategies could reduce the inherent risk of steatotic liver failure after transplantation.
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Affiliation(s)
- M B Jiménez-Castro
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBPAS), Barcelona, Spain
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169
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Gupta S, Li S, Abedin MJ, Noppakun K, Wang L, Kaur T, Najafian B, Rodrigues CMP, Steer CJ. Prevention of acute kidney injury by tauroursodeoxycholic acid in rat and cell culture models. PLoS One 2012; 7:e48950. [PMID: 23152827 PMCID: PMC3494686 DOI: 10.1371/journal.pone.0048950] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/02/2012] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Acute kidney injury (AKI) has grave short- and long-term consequences. Often the onset of AKI is predictable, such as following surgery that compromises blood flow to the kidney. Even in such situations, present therapies cannot prevent AKI. As apoptosis is a major form of cell death following AKI, we determined the efficacy and mechanisms of action of tauroursodeoxycholic acid (TUDCA), a molecule with potent anti-apoptotic and pro-survival properties, in prevention of AKI in rat and cell culture models. TUDCA is particularly attractive from a translational standpoint, as it has a proven safety record in animals and humans. METHODOLOGY/PRINCIPAL FINDINGS We chose an ischemia-reperfusion model in rats to simulate AKI in native kidneys, and a human kidney cell culture model to simulate AKI associated with cryopreservation in transplanted kidneys. TUDCA significantly ameliorated AKI in the test models due to inhibition of the mitochondrial pathway of apoptosis and upregulation of survival pathways. CONCLUSIONS This study sets the stage for testing TUDCA in future clinical trials for prevention of AKI, an area that needs urgent attention due to lack of effective therapies.
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Affiliation(s)
- Sandeep Gupta
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Shunan Li
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Md. Joynal Abedin
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Kajohnsak Noppakun
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Lawrence Wang
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Tarundeep Kaur
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Behzad Najafian
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Cecília M. P. Rodrigues
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | - Clifford J. Steer
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
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170
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Murai M, Inoue T, Suzuki-Karasaki M, Ochiai T, Ra C, Nishida S, Suzuki-Karasaki Y. Diallyl trisulfide sensitizes human melanoma cells to TRAIL-induced cell death by promoting endoplasmic reticulum-mediated apoptosis. Int J Oncol 2012; 41:2029-37. [PMID: 23064375 DOI: 10.3892/ijo.2012.1656] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/07/2012] [Indexed: 02/07/2023] Open
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is promising for cancer treatment because of its selective cytotoxicity toward tumor cells. However, some cancer cell types including malignant melanoma cells are resistant to TRAIL cytotoxicity. Here, we show that diallyl trisulfide (DATS), a garlic organosulfur compound, sensitizes melanoma cells to TRAIL-induced apoptosis while sparing normal cells. DATS also potentiates apoptosis induced by agonistic antibodies against death receptors (DR) 4 and DR5. The amplification of DR-mediated apoptosis was associated with increased mitochondrial membrane potential collapse and caspase-3/7 activation. However, these events were not sufficient for full sensitization. TRAIL also induced endoplasmic reticulum (ER) stress, as indicated by the activation of X-box-binding protein 1 and caspase-12 and DATS poten-tiated both events. Moreover, inhibition of caspase-12, but not caspase-4, abolished the amplification of apoptosis, indicating that ER stress plays a crucial role. On the other hand, DATS and/or TRAIL induced minimal apoptosis and caspase-12 activation in melanocytes despite their substantial expression of DR4 and DR5 on the cell surface. Our data suggest that DATS amplifies death ligand-induced melanoma cell death by disrupting their adaptation to ER-mediated death pathway. The present findings raise the possibility that DATS may be combined with death ligands to treat TRAIL-resistance melanoma cells without impairing its tumor selectivity.
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Affiliation(s)
- Mayumi Murai
- Division of Molecular Cell Immunology and Allergology, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan
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171
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Abstract
Ursodeoxycholic acid (UDCA) is one of hepatologists'oldest friends, always ready to help, throughout the years, in numerous and various liver and biliary tract diseases. On paper, it has had an impeccable track record of cytoprotection in vitro and in vivo due to its pleiotropic effects on many pathways leading to cell injury. Most of its hepatoprotective effects demonstrated under experimental conditions proved able to counteract pathogenic mechanisms involved in the transition from steatosis to steatohepatitis, and early clinical studies suggested a potentially beneficial effect in non-alcoholic steatohepatitis (NASH) as well. Yet, only scant data on the efficacy of UDCA specifically in experimental models of steatosis/NASH are available, and the few available randomized controlled clinical studies have substantial methodological issues and are discussed in this review. Thus, at this point, there is not enough evidence to either confirm or reject the efficacy of UDCA in NASH, although many NASH patients clearly experience biochemical improvements with prolonged UDCA treatment. Also, a few new UDCA derivatives have shown promising activity in preclinical models and may be worth testing in clinical trials.
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Affiliation(s)
- Vlad Ratziu
- Service d'Hépato-gastro-entérologie, Hôpital Pitié-Salpêtrière, 47-83, boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
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172
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Poupon R. Ursodeoxycholic acid and bile-acid mimetics as therapeutic agents for cholestatic liver diseases: an overview of their mechanisms of action. Clin Res Hepatol Gastroenterol 2012; 36 Suppl 1:S3-12. [PMID: 23141891 DOI: 10.1016/s2210-7401(12)70015-3] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chronic cholestasis and liver inflammation are the two main pathophysiological components of the two major classes of disease - primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) - leading to bile duct destruction and ultimately to cirrhosis and liver failure. Ursodeoxycholic acid (UDCA), initially introduced as a therapeutic approach to counteract the cholestatic components to PBC and PSC, was subsequently shown to exhibit unexpected anti-inflammatory and immunomodulatoty properties. The use of farnesoid X receptor (FXR) and TGR5 agonists in various animal models have confirmed early observations indicating that bile acids are not only toxicants and inflammagens, but also repressors of innate and adaptive immunity. Obeticholic acid is a bile-acid mimetic, with no toxic or inflammagen behavior, that strongly activates FXR to combat the toxic effects of high concentrations of bile acid. Because UDCA is not an FXR agonist, its combination with obeticholic acid could be a promising tool for the treatment of PBC and PSC. In this overview, the biological properties of UDCA, NorUDCA and FXR agonists are highlighted, as well as their overlapping mechanisms of action in inflammatory biliary disorders.
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Affiliation(s)
- Raoul Poupon
- Service d'Hépatologie et Centre de Référence des maladies inflammatoires des voies biliaires, Hôpital Saint-Antoine, AP-HP, 184, rue du Faubourg Saint-Antoine, 75571 Paris cedex 12, France.
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173
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Suzuki Y, Inoue T, Murai M, Suzuki-Karasaki M, Ochiai T, Ra C. Depolarization potentiates TRAIL-induced apoptosis in human melanoma cells: role for ATP-sensitive K+ channels and endoplasmic reticulum stress. Int J Oncol 2012; 41:465-75. [PMID: 22613960 PMCID: PMC3582902 DOI: 10.3892/ijo.2012.1483] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Accepted: 04/10/2012] [Indexed: 01/21/2023] Open
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is promising for cancer treatment owing to its selective cytotoxicity against malignant cells. However, some cancer cell types, including malignant melanoma cells, are resistant to TRAIL-induced apoptosis. Therefore, drugs that can amplify TRAIL cytotoxicity are urgently required. Depolarization of the plasma membrane potential is associated with apoptosis induced by a variety of death-inducing agents but its role in apoptosis remains a matter of debate. We found that TRAIL treatment resulted in robust depolarization in human melanoma cells with a considerable lag (2-4 h). Moreover, membrane-depolarizing agents, including K+ and ATP-sensitive K+ (KATP) channel inhibitors glibenclamide and U37883A enhanced TRAIL-induced apoptosis. On the contrary, inhibitors of calcium- and voltage-dependent K+ channels and mitochondrial KATP channels had no such effects. Melanocytes were insensitive to TRAIL-induced depolarization and apoptosis as well as to the sensitization by membrane-depolarizing agents despite their substantial surface expression of death receptors. TRAIL induced robust activation of X-box-binding protein-1 and caspase-12, both of which were enhanced by the K+ and KATP channel inhibitors, but not by other K+ channel inhibitors. Finally, caspase-12-selective inhibitor completely abolished the amplification of apoptosis. These findings suggest that depolarization promotes endoplasmic reticulum stress-mediated death pathway, thereby amplifying TRAIL cytotoxicity. Thus, membrane-depolarizing agents such as KATP channel inhibitors may have therapeutic potential in the treatment of TRAIL-resistant cancer cells without impairing tumor-selectivity.
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Affiliation(s)
- Yoshihiro Suzuki
- Nihon University Graduate School of Medical Science, Tokyo, Japan.
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174
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Inhibition of endoplasmic reticulum stress improves mouse embryo development. PLoS One 2012; 7:e40433. [PMID: 22808162 PMCID: PMC3396646 DOI: 10.1371/journal.pone.0040433] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 06/06/2012] [Indexed: 01/08/2023] Open
Abstract
X-box binding protein-1 (XBP-1) is an important regulator of a subset of genes during endoplasmic reticulum (ER) stress. In the current study, we analyzed endogenous XBP-1 expression and localization, with a view to determining the effects of ER stress on the developmental competency of preimplantation embryos in mice. Fluorescence staining revealed that functional XBP-1 is localized on mature oocyte spindles and abundant in the nucleus at the germinal vesicle (GV) stage. However, in preimplantation embryos, XBP-1 was solely detected in the cytoplasm at the one-cell stage. The density of XBP-1 was higher in the nucleus than the cytoplasm at the two-cell, four-cell, eight-cell, morula, and blastocyst stages. Furthermore, RT-PCR analysis confirmed active XBP-1 mRNA splicing at all preimplantation embryo stages, except the one-cell stage. Tunicamycin (TM), an ER stress inducer used as a positive control, promoted an increase in the density of nuclear XBP-1 at the one-cell and two-cell stages. Similarly, culture medium supplemented with 25 mM sorbitol displayed a remarkable increase active XBP-1 expression in the nuclei of 1-cell and 2-cell embryos. Conversely, high concentrations of TM or sorbitol led to reduced nuclear XBP-1 density and significant ER stress-induced apoptosis. Tauroursodeoxycholic acid (TUDCA), a known inhibitor of ER stress, improved the rate of two-cell embryo development to blastocysts by attenuating the expression of active XBP-1 protein in the nucleus at the two-cell stage. Our data collectively suggest that endogenous XBP-1 plays a role in normal preimplantation embryonic development. Moreover, XBP-1 splicing is activated to generate a functional form in mouse preimplantation embryos during culture stress. TUDCA inhibits hyperosmolar-induced ER stress as well as ER stress-induced apoptosis during mouse preimplantation embryo development.
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175
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Henkel AS, Dewey AM, Anderson KA, Olivares S, Green RM. Reducing endoplasmic reticulum stress does not improve steatohepatitis in mice fed a methionine- and choline-deficient diet. Am J Physiol Gastrointest Liver Physiol 2012; 303:G54-9. [PMID: 22556147 PMCID: PMC3404574 DOI: 10.1152/ajpgi.00052.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of nonalcoholic steatohepatitis. The ER stress response is activated in the livers of mice fed a methionine- and choline-deficient (MCD) diet, yet the role of ER stress in the pathogenesis of MCD diet-induced steatohepatitis is unknown. Using chemical chaperones on hepatic steatosis and markers of inflammation and fibrosis in mice fed a MCD diet, we aim to determine the effects of reducing ER stress. C57BL/6J mice were fed a MCD diet with or without the ER chemical chaperones 4-phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) for 2 wk. TUDCA and PBA effectively attenuated the ER stress response in MCD diet-fed mice, as evidenced by reduced protein levels of phosphorylated eukaryotic initiation factor 2α and phosphorylated JNK and suppression of mRNA levels of CCAAT/enhancer binding protein homologous protein, glucose-regulated protein 78 kDa, and X-box binding protein 1. However, PBA and TUDCA did not decrease MCD diet-induced hepatic steatosis. MCD diet-induced hepatic inflammation, as evidenced by increased plasma alanine aminotransferase and induction of hepatic TNFα expression, was also not reduced by PBA or TUDCA. PBA and TUDCA did not attenuate MCD diet-induced upregulation of the fibrosis-associated genes tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9. ER chemical chaperones reduce MCD diet-induced ER stress, yet they do not improve MCD diet-induced hepatic steatosis, inflammation, or activation of genes associated with fibrosis. These data suggest that although the ER stress response is activated by the MCD diet, it does not have a primary role in the pathogenesis of MCD diet-induced steatohepatitis.
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Affiliation(s)
- Anne S. Henkel
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Amanda M. Dewey
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Kristy A. Anderson
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Shantel Olivares
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Richard M. Green
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
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176
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Achard CS, Laybutt DR. Lipid-induced endoplasmic reticulum stress in liver cells results in two distinct outcomes: adaptation with enhanced insulin signaling or insulin resistance. Endocrinology 2012; 153:2164-77. [PMID: 22374970 DOI: 10.1210/en.2011-1881] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronically elevated fatty acids contribute to insulin resistance through poorly defined mechanisms. Endoplasmic reticulum (ER) stress and the subsequent unfolded protein response (UPR) have been implicated in lipid-induced insulin resistance. However, the UPR is also a fundamental mechanism required for cell adaptation and survival. We aimed to distinguish the adaptive and deleterious effects of lipid-induced ER stress on hepatic insulin action. Exposure of human hepatoma HepG2 cells or mouse primary hepatocytes to the saturated fatty acid palmitate enhanced ER stress in a dose-dependent manner. Strikingly, exposure of HepG2 cells to prolonged mild ER stress activation induced by low levels of thapsigargin, tunicamycin, or palmitate augmented insulin-stimulated Akt phosphorylation. This chronic mild ER stress subsequently attenuated the acute stress response to high-level palmitate challenge. In contrast, exposure of HepG2 cells or hepatocytes to severe ER stress induced by high levels of palmitate was associated with reduced insulin-stimulated Akt phosphorylation and glycogen synthesis, as well as increased expression of glucose-6-phosphatase. Attenuation of ER stress using chemical chaperones (trimethylamine N-oxide or tauroursodeoxycholic acid) partially protected against the lipid-induced changes in insulin signaling. These findings in liver cells suggest that mild ER stress associated with chronic low-level palmitate exposure induces an adaptive UPR that enhances insulin signaling and protects against the effects of high-level palmitate. However, in the absence of chronic adaptation, severe ER stress induced by high-level palmitate exposure induces deleterious UPR signaling that contributes to insulin resistance and metabolic dysregulation.
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Affiliation(s)
- Caroline S Achard
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, Australia
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Low glucose under hypoxic conditions induces unfolded protein response and produces reactive oxygen species in lens epithelial cells. Cell Death Dis 2012; 3:e301. [PMID: 22513875 PMCID: PMC3358018 DOI: 10.1038/cddis.2012.40] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aging is enhanced by hypoxia and oxidative stress. As the lens is located in the hypoglycemic environment under hypoxia, aging lens with diabetes might aggravate these stresses. This study was designed to examine whether low glucose under hypoxic conditions induces the unfolded protein response (UPR), and also if the UPR then generates the reactive oxygen species (ROS) in lens epithelial cells (LECs). The UPR was activated within 1 h by culturing the human LECs (HLECs) and rat LECs in <1.5 mM glucose under hypoxic conditions. These conditions also induced the Nrf2-dependent antioxidant-protective UPR, production of ROS, and apoptosis. The rat LECs located in the anterior center region were the least susceptible to the UPR, whereas the proliferating LECs in the germinative zone were the most susceptible. Because the cortical lens fiber cells are differentiated from the LECs after the onset of diabetes, we suggest that these newly formed cortical fibers have lower levels of Nrf2, and are then oxidized resulting in cortical cataracts. Thus, low glucose and oxygen conditions induce the UPR, generation of ROS, and expressed the Nrf2 and Nrf2-dependent antioxidant enzymes at normal levels. But these cells eventually lose reduced glutathione (GSH) and induce apoptosis. The results indicate a new link between hypoglycemia under hypoxia and impairment of HLEC functions.
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178
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Zhang JY, Diao YF, Oqani RK, Han RX, Jin DI. Effect of Endoplasmic Reticulum Stress on Porcine Oocyte Maturation and Parthenogenetic Embryonic Development In Vitro1. Biol Reprod 2012; 86:128. [DOI: 10.1095/biolreprod.111.095059] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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179
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Refined Qingkailing Protects MCAO Mice from Endoplasmic Reticulum Stress-Induced Apoptosis with a Broad Time Window. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:567872. [PMID: 22536287 PMCID: PMC3320064 DOI: 10.1155/2012/567872] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 11/18/2022]
Abstract
In the current study, we are investigating effect of refined QKL on ischemia-reperfusion-induced brain injury in mice. Methods. Mice were employed to induce ischemia-reperfusion injury of brain by middle cerebral artery occlusion (MCAO). RQKL solution was administered with different doses (0, 1.5, 3, and 6 mL/kg body weight) at the same time of onset of ischemia, and with the dose of 1.5 mL/kg at different time points (0, 1.5, 3, 6, and 9 h after MCAO). Neurological function and brain infarction were examined and cell apoptosis and ROS at prefrontal cortex were evaluated 24 h after MCAO, and western blot and intracellular calcium were also researched, respectively. Results. RQKL of all doses can improve neurological function and decrease brain infarction, and it performed significant effect in 0, 1.5, 3, and 6 h groups. Moreover, RQKL was able to reduce apoptotic process by reduction of caspase-3 expression, or restraint of eIF2a phosphorylation and caspase-12 activation. It was also able to reduce ROS and modulate intracellular calcium in the brain. Conclusion. RQKL can prevent ischemic-induced brain injury with a time window of 6 h, and its mechanism might be related to suppress ER stress-mediated apoptotic signaling.
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180
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TANG HEZHEN, YANG LIMIN. Activation of the unfolded protein response in aged human lenses. Mol Med Rep 2012; 12:389-93. [DOI: 10.3892/mmr.2015.3417] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 11/20/2014] [Indexed: 11/05/2022] Open
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181
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The role of glucosamine-induced ER stress in diabetic atherogenesis. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:187018. [PMID: 22474416 PMCID: PMC3296270 DOI: 10.1155/2012/187018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 11/27/2011] [Indexed: 12/14/2022]
Abstract
Cardiovascular disease (CVD) is the major cause of mortality in individuals with diabetes mellitus. However the molecular and cellular mechanisms that predispose individuals with diabetes to the development and progression of atherosclerosis, the underlying cause of most CVD, are not understood. This paper summarizes the current state of our knowledge of pathways and mechanisms that may link diabetes and hyperglycemia to atherogenesis. We highlight recent work from our lab, and others', that supports a role for ER stress in these processes. The continued investigation of existing pathways, linking hyperglycemia and diabetes mellitus to atherosclerosis, and the identification of novel mechanisms and targets will be important to the development of new and effective antiatherosclerotic therapies tailored to individuals with diabetes.
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182
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Ursodeoxycholic acid in cholestasis: linking action mechanisms to therapeutic applications. Clin Sci (Lond) 2011; 121:523-44. [PMID: 21854363 DOI: 10.1042/cs20110184] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UDCA (ursodeoxycholic acid) is the therapeutic agent most widely used for the treatment of cholestatic hepatopathies. Its use has expanded to other kinds of hepatic diseases, and even to extrahepatic ones. Such versatility is the result of its multiple mechanisms of action. UDCA stabilizes plasma membranes against cytolysis by tensioactive bile acids accumulated in cholestasis. UDCA also halts apoptosis by preventing the formation of mitochondrial pores, membrane recruitment of death receptors and endoplasmic-reticulum stress. In addition, UDCA induces changes in the expression of metabolizing enzymes and transporters that reduce bile acid cytotoxicity and improve renal excretion. Its capability to positively modulate ductular bile flow helps to preserve the integrity of bile ducts. UDCA also prevents the endocytic internalization of canalicular transporters, a common feature in cholestasis. Finally, UDCA has immunomodulatory properties that limit the exacerbated immunological response occurring in autoimmune cholestatic diseases by counteracting the overexpression of MHC antigens and perhaps by limiting the production of cytokines by immunocompetent cells. Owing to this multi-functionality, it is difficult to envisage a substitute for UDCA that combines as many hepatoprotective effects with such efficacy. We predict a long-lasting use of UDCA as the therapeutic agent of choice in cholestasis.
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183
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Carbon monoxide, a reaction product of heme oxygenase-1, suppresses the expression of C-reactive protein by endoplasmic reticulum stress through modulation of the unfolded protein response. Mol Immunol 2011; 48:1793-9. [DOI: 10.1016/j.molimm.2011.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 04/30/2011] [Accepted: 05/09/2011] [Indexed: 11/24/2022]
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184
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Kim SY, Kwon YW, Jung IL, Sung JH, Park SG. Tauroursodeoxycholate (TUDCA) inhibits neointimal hyperplasia by suppression of ERK via PKCα-mediated MKP-1 induction. Cardiovasc Res 2011; 92:307-16. [PMID: 21840882 DOI: 10.1093/cvr/cvr219] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AIMS Hyperplasia of vascular smooth muscle cells (VSMCs) after blood vessel injury is one of the major pathophysiological mechanisms associated with neointima. Tauroursodeoxycholate (TUDCA) is a cytoprotective agent in a variety of cells including hepatocytes as well as an inducer of apoptosis in cancer cells. In this study, we investigated whether TUDCA could prevent neointimal hyperplasia by suppressing the growth and migration of VSMCs. METHODS AND RESULTS Transporters of TUDCA uptake in human VSMCs (hVSMCs) were analysed by RT-PCR and western blot. A knock-down experiment using specific si-RNA revealed that TUDCA was incorporated into hVSMCs via organic anion transporter 2 (OATP2). TUDCA reduced the viability of hVSMCs, which were mediated by inhibition of extracellular signal-regulated kinase (ERK) by induction of mitogen-activated protein kinase phosphatase-1 (MKP-1) via protein kinase Cα (PKCα). The anti-proliferative effect of TUDCA was reversed by treatment with 7-hydroxystaurosporine, an inhibitor of PKC, and by the knock-down of MKP-1. In addition, TUDCA suppressed hVSMC migration, which was mediated by reduced matrix metalloproteinase-9 (MMP-9) expression by ERK inhibition, as well as reduced viability of hVSMCs. Rats with carotid artery balloon injury received oral administration of TUDCA; this reduced the increase in ERK and MMP-9 caused by balloon injury. TUDCA significantly decreased the ratio of intima to media by reducing proliferation and inducing apoptosis of the VSMCs. CONCLUSION TUDCA inhibits neointimal hyperplasia by reducing proliferation and inducing apoptosis of smooth muscle cells by suppression of ERK via PKCα-mediated MKP-1 induction.
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Affiliation(s)
- Seo Yoon Kim
- Department of Biomedical Science, CHA University, 606-16, Yeoksamdong, Kangnamgu, Seoul 135-081, Republic of Korea
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185
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Abstract
With the epidemic of childhood obesity, nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease in pediatrics. NAFLD is strongly associated with insulin resistance and increased level of serum free fatty acids (FFAs). FFAs have direct hepatotoxicity through the induction of an endoplasmic reticulum stress response and subsequently activation of the mitochondrial pathway of cell death. FFAs may also result in lysosomal dysfunction and alter death receptor gene expression. Lipoapoptosis is a key pathogenic process in NAFLD, and correlates with progressive inflammation, and fibrosis. Accumulation of triglyceride in the liver results from uptake and esterification of FFAs by the hepatocyte, and is less likely to be hepatotoxic per se. To date, there are no proven effective therapies that halt NAFLD progression or unfortunately improve prognosis in children. The cellular mechanisms of lipotoxicity are complex but provide potential therapeutic targets for NAFLD. In this review we discuss several potential therapeutic opportunities in detail including inhibition of apoptosis, c-Jun-N-terminal kinase, and endoplasmic reticulum stress pathways.
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186
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Fatma N, Singh P, Chhunchha B, Kubo E, Shinohara T, Bhargavan B, Singh DP. Deficiency of Prdx6 in lens epithelial cells induces ER stress response-mediated impaired homeostasis and apoptosis. Am J Physiol Cell Physiol 2011; 301:C954-67. [PMID: 21677259 DOI: 10.1152/ajpcell.00061.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The multifunctional cytoprotective protein peroxiredoxin 6 (Prdx6) maintains cellular homeostasis and membrane integrity by regulating expression of intracellular reactive oxygen species (ROS) and phospholipid turnover. Using cells derived from targeted inactivation of Prdx6 gene or its depletion by RNA interference or aging, we showed that Prdx6 deficiency in cells evoked unfolded protein response (UPR), evidenced by increased expression or activation of proapoptotic factors, CHOP, ATF4, PERK, IRE-α and eIF2-α and by increased caspases 3 and 12 processing. Those cells displayed enhanced and sustained expression of endoplasmic reticulum (ER) stress-related chaperon proteins, Bip/glucose-regulated protein 78, calnexin, and calreticulin. Under cellular stress induced by hypoxia (1% O(2) or CoCl(2) treatment) or tunicamycin, Prdx6-deficient cells exhibited aberrant activation of ER stress-responsive genes/protein with higher expression of ROS, and died with apoptosis. Wild-type cells exposed to tunicamycin or hypoxia remained relatively insensitive with lower expression of ROS and ER-responsive genes than did Prdx6-deficient cells, but upregulation of ER stress responsive proteins or chaperones mimicked the UPR response of Prdx6-deficient or aging cells. Expression of Prdx6 blocked ER stress-induced deleterious signaling by optimizing physiologically aberrant expression of ER stress responsive genes/proteins in Prdx6-deficient cells or cells facing stressors, and rescued the cells from apoptosis. These findings demonstrate that impaired homeostasis and progression of pathogenesis in Prdx6-deficient lens epithelial cells or in aging cells should be blocked by a supply of Prdx6. The results provide a new molecular basis for understanding the etiology of several age-associated degenerative disorders, and potentially for developing antioxidant Prdx6-based therapeutics.
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Affiliation(s)
- Nigar Fatma
- Dept. of Ophthalmology and Visual Sciences, Univ. of Nebraska Medical Center, Omaha, 68198-5840, USA
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187
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Lee SA, Belyaeva OV, Kedishvili NY. Evidence that proteosome inhibitors and chemical chaperones can rescue the activity of retinol dehydrogenase 12 mutant T49M. Chem Biol Interact 2011; 191:55-9. [PMID: 21232531 DOI: 10.1016/j.cbi.2011.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 12/30/2010] [Accepted: 01/04/2011] [Indexed: 11/29/2022]
Abstract
Retinol dehydrogenase 12 (RDH12) is a microsomal enzyme that catalyzes the reduction of all-trans-retinaldehyde to all-trans-retinol when expressed in cells. Mutations in RDH12 cause severe retinal degeneration; however, some of the disease-associated RDH12 mutants retain significant catalytic activity. Our previous study (Lee et al., 2010 [9]) demonstrated that the catalytically active T49M and I51N variants of RDH12 undergo accelerated degradation through the ubiquitin-proteosome system, which results in reduced levels of these proteins in the cells. Here, we investigated whether the stabilization of T49M or I51N RDH12 protein levels through the inhibition of proteosome activity or improved folding could rescue their retinaldehyde reductase activity. For the T49M variant, the inhibition of proteosome activity resulted in an increased level of T49M protein in the microsomal fraction. The higher level of the T49M variant in microsomes correlated with the higher microsomal retinaldehyde reductase activity. T49M-expressing living cells treated with the inhibitors of proteosome activity or with dimethyl sulfoxide exhibited an increase in the conversion of retinaldehyde to retinol, consistent with the recovery of functional RDH12 protein. On the other hand, accumulation of the I51N variant in the microsomes did not result in higher retinaldehyde reductase activity of the microsomes or cells. These results provide a proof of concept that, at least in the case of the T49M variant, the prevention of accelerated degradation could lead to restoration of its function in the cells. This finding justifies further search for more efficient and clinically relevant compounds for stabilizing the T49M variant activity.
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Affiliation(s)
- Seung-Ah Lee
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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188
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Berger E, Haller D. Structure-function analysis of the tertiary bile acid TUDCA for the resolution of endoplasmic reticulum stress in intestinal epithelial cells. Biochem Biophys Res Commun 2011; 409:610-5. [PMID: 21605547 DOI: 10.1016/j.bbrc.2011.05.043] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 12/23/2022]
Abstract
Inflammatory bowel diseases (IBD) are chronically relapsing and immune-mediated disorders of the gastrointestinal tract. Endoplasmic reticulum (ER) stress mechanisms in the epithelium have been demonstrated to be implemented into the pathogenesis of intestinal inflammation. Chemical chaperones have been demonstrated to exhibit beneficial effects in various diseases associated with ER stress mechanisms by prohibiting the unfolded protein response (UPR). In a structure-function analysis, we tested the potential of the conjugated bile salt sodium tauroursodeoxycholate (TUDCA), naturally present in the small bowel, to resolve ER stress in intestinal epithelial cells. TUDCA efficiently inhibited the expression of UPR dependent genes like GRP78 triggered by the ER stressor tunicamycin in the small intestinal epithelial cell line Mode-K. TUDCA inhibited upstream signaling events in all three branches of the UPR cascade and diminished binding of UPR activated transcription factors to the grp78 promoter. A structure-function analysis revealed that UDCA but not its conjugation partner taurine, known as a chemical chaperone, is responsible for the inhibition of GRP78 induction and that UDCA is 10 times more effective than its taurine conjugate. This inhibitory effect was confirmed in a cell free assay, where TUDCA and UDCA but not taurine effectively inhibited the aggregation of thermally denatured BSA. We conclude that TUDCA and UDCA are potent anti-aggregants for the resolution of ER stress in intestinal epithelial cells and should be considered as a potential drug target to resolve ER stress mechanisms underlying the pathology of IBD.
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Affiliation(s)
- Emanuel Berger
- Chair for Biofunctionality, ZIEL Research Center for Nutrition and Food Science, CDD Center for Diet and Disease, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising-Weihenstephan, Germany
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189
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A randomized controlled trial of high-dose ursodesoxycholic acid for nonalcoholic steatohepatitis. J Hepatol 2011; 54:1011-9. [PMID: 21145828 DOI: 10.1016/j.jhep.2010.08.030] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 08/02/2010] [Accepted: 08/15/2010] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH) is a prevalent liver disease associated with increased morbidity and mortality. Ursodeoxycholic acid (UDCA) may have antioxidant, anti-inflammatory, and antifibrotic properties and may reduce liver injury in NASH. To date, no studies have assessed the efficacy and safety of high-dose UDCA (HD-UDCA) in patients with NASH. METHODS We conducted a 12-month, randomized, double-blind, placebo-controlled multicenter trial to evaluate the efficacy and safety of HD-UDCA (28-35 mg/kg per day) in 126 patients with biopsy-proven NASH and elevated alanine aminotransferase (ALT) levels. The primary study end point was reduction in ALT levels from baseline in patients treated with HD-UDCA compared with placebo. Secondary study end points were the proportion of patients with ALT normalization, relative reduction in the scores of serum markers of fibrosis and hepatic inflammation, and safety and tolerability. RESULTS HD-UDCA significantly reduced mean ALT levels -28.3% from baseline after 12 months compared with -1.6% with placebo (p<0.001). At the end of the trial, ALT levels normalized (≤35 IU/L) in 24.5% of patients treated with HD-UDCA and in 4.8% of patients who received placebo (p=0.003). Both results were not accounted for by changes in weight during the trial. HD-UDCA significantly reduced the FibroTest® serum fibrosis marker (p<0.001) compared with placebo. HD-UDCA also significantly improved markers of glycemic control and insulin resistance. There were no safety issues in this population. CONCLUSIONS Treatment with HD-UDCA was safe, improved aminotransferase levels, serum fibrosis markers, and selected metabolic parameters. Studies with histologic end points are warranted.
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190
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Mooradian AD, Haas MJ. Glucose-induced endoplasmic reticulum stress is independent of oxidative stress: A mechanistic explanation for the failure of antioxidant therapy in diabetes. Free Radic Biol Med 2011; 50:1140-3. [PMID: 21320588 DOI: 10.1016/j.freeradbiomed.2011.02.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/02/2011] [Accepted: 02/07/2011] [Indexed: 02/07/2023]
Abstract
Oxidative stress contributes to the pathogenesis of diabetes and its complications. However, a large number of interventional studies have failed to show any health benefits of antioxidants. The overwhelming failure of antioxidant therapy to prevent disease can be explained by inadequacy of the doses of antioxidants used, short duration of therapy, or poor timing of initiation of the supplementation. A more likely reason for failure of antioxidants to reduce diabetes-related complications is the multiplicity of mechanisms of glucotoxicity that are independent of oxidative stress. Recently, endoplasmic reticulum (ER) stress has emerged as an important contributor to diabetes-related complications. Multiple lines of experimental evidence indicate that ER stress in endothelial cells can be uncoupled from oxidative stress induced by hyperglycemia, and antioxidants can ameliorate the latter without altering the ER stress. These observations provide a novel mechanistic explanation for the failure of antioxidant therapy in interventional clinical trials.
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Affiliation(s)
- Arshag D Mooradian
- Department of Medicine, University of Florida College of Medicine, Jacksonville, FL 32209, USA.
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191
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Dobashi T, Tanabe S, Jin H, Mimura N, Yamamoto T, Nishino T, Aoe T. BiP, an endoplasmic reticulum chaperone, modulates the development of morphine antinociceptive tolerance. J Cell Mol Med 2011; 14:2816-26. [PMID: 19818092 PMCID: PMC3822731 DOI: 10.1111/j.1582-4934.2009.00932.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Morphine is a potent analgesic, but the molecular mechanism for tolerance formation after repeated use is not fully understood. Binding immunoglobulin protein (BiP) is an endoplasmic reticulum (ER) chaperone that is central to ER function. We examined knock-in mice expressing a mutant BiP with the retrieval sequence deleted in order to elucidate physiological processes that are sensitive to BiP functions. We tested the thermal antinociceptive effect of morphine in heterozygous mutant BiP mice in a hot plate test. Paw withdrawal latencies before and after a single administration of morphine were not significantly different between the wild-type and mutant BiP mice. Repeated morphine administration caused the development of morphine tolerance in the wild-type mice. The activation of glycogen synthase kinase 3b (GSK-3b) was associated with morphine tolerance, because an inhibitor of GSK-3β prevented it. On the other hand, the mutant BiP mice showed less morphine tolerance, and the activation of GSK-3b was suppressed in their brain. These results suggest that BiP may play an important role in the development of morphine tolerance. Furthermore, we found that a chemical chaperone which improves ER protein folding capacity also attenuated the development of morphine tolerance in wild-type mice, suggesting a possible clinical application of chemical chaperones in preventing morphine tolerance.
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Affiliation(s)
- Tamae Dobashi
- Department of Anesthesiology, Chiba University Graduate School of Medicine, Chiba, Japan
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192
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Yeo J, Kang YM, Cho SI, Jung MH. Effects of a multi-herbal extract on type 2 diabetes. Chin Med 2011; 6:10. [PMID: 21375727 PMCID: PMC3060155 DOI: 10.1186/1749-8546-6-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 03/04/2011] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND An aqueous extract of multi-hypoglycemic herbs of Panax ginseng C.A.Meyer, Pueraria lobata, Dioscorea batatas Decaisne, Rehmannia glutinosa, Amomum cadamomum Linné, Poncirus fructus and Evodia officinalis was investigated for its anti-diabetic effects in cell and animal models. METHODS Activities of PPARγ agonist, anti-inflammation, AMPK activator and anti-ER stress were measured in cell models and in db/db mice (a genetic animal model for type 2 diabetes). RESULTS While the extract stimulated PPARγ-dependent luciferase activity and activated AMPK in C2C12 cells, it inhibited TNF-α-stimulated IKKβ/NFkB signaling and attenuated ER stress in HepG2 cells. The db/db mice treated with the extract showed reduced fasting blood glucose and HbA1c levels, improved postprandial glucose levels, enhanced insulin sensitivity and significantly decreased plasma free fatty acid, triglyceride and total cholesterol. CONCLUSION The aqueous extract of these seven hypoglycemic herbs demonstrated many therapeutic effects for the treatment of type 2 diabetes in cell and animal models.
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Affiliation(s)
- Jiyoung Yeo
- School of Korean Medicine, Pusan National University, Beomeo-ri, Mulguem-eup, Yangsan, Gyeongsangnam-do, 626-770, South Korea.
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193
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Anderson CD, Upadhya G, Conzen KD, Jia J, Brunt EM, Tiriveedhi V, Xie Y, Ramachandran S, Mohanakumar T, Davidson NO, Chapman WC. Endoplasmic reticulum stress is a mediator of posttransplant injury in severely steatotic liver allografts. Liver Transpl 2011; 17:189-200. [PMID: 21280192 PMCID: PMC3056557 DOI: 10.1002/lt.22220] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hepatic steatosis continues to present a major challenge in liver transplantation. These organs have been shown to have increased susceptibility to cold ischemia/reperfusion (CIR) injury in comparison with otherwise comparable lean livers; the mechanisms governing this increased susceptibility to CIR injury are not fully understood. Endoplasmic reticulum (ER) stress is an important link between hepatic steatosis, insulin resistance, and metabolic syndrome. In this study, we investigated ER stress signaling and blockade in the mediation of CIR injury in severely steatotic rodent allografts. Steatotic allografts from genetically leptin-resistant rodents had increased ER stress responses and increased markers of hepatocellular injury after liver transplantation into strain-matched lean recipients. ER stress response components were reduced by the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA), and this resulted in an improvement in the allograft injury. TUDCA treatment decreased nuclear factor kappa B activation and the proinflammatory cytokines interleukin-6 and interleukin-1β. However, the predominant response was decreased expression of the ER stress cell death mediator [CCAAT/enhancer-binding protein homologous protein (CHOP)]. Furthermore, activation of inflammation-associated caspase-11 was decreased, and this linked ER stress/CHOP to proinflammatory cytokine production after steatotic liver transplantation. These data confirm ER stress in steatotic allografts and implicate this as a mediating mechanism of inflammation and hepatocyte death in the steatotic liver allograft.
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Affiliation(s)
- Christopher D. Anderson
- Department of Surgery, Washington University in St. Louis, St. Louis, MO,To whom correspondence should be addressed: Christopher D. Anderson, MD, Assistant Professor of Surgery, 660 S. Euclid Ave, Campus Box 8109, St. Louis, MO 63110, Office: 314-362-2538, Fax: 314-361-4197,
| | - Gundumi Upadhya
- Department of Surgery, Washington University in St. Louis, St. Louis, MO
| | - Kendra D. Conzen
- Department of Surgery, Washington University in St. Louis, St. Louis, MO
| | - Jianlou Jia
- Department of Surgery, Washington University in St. Louis, St. Louis, MO
| | - Elizabeth M. Brunt
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | | | - Yan Xie
- Department of Medicine, Washington University in St. Louis, St. Louis, MO
| | | | | | | | - William C. Chapman
- Department of Surgery, Washington University in St. Louis, St. Louis, MO
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Huang SM, Cheung CW, Chang CS, Tang CH, Liu JF, Lin YH, Chen JH, Ko SH, Wong KL, Lu DY. Phloroglucinol derivative MCPP induces cell apoptosis in human colon cancer. J Cell Biochem 2011; 112:643-52. [DOI: 10.1002/jcb.22966] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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195
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Gillard BK, Rosales C, Pillai BK, Lin HY, Courtney HS, Pownall HJ. Streptococcal serum opacity factor increases the rate of hepatocyte uptake of human plasma high-density lipoprotein cholesterol. Biochemistry 2010; 49:9866-73. [PMID: 20879789 PMCID: PMC2982792 DOI: 10.1021/bi101412m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Serum opacity factor (SOF), a virulence determinant of Streptococcus pyogenes, converts plasma high-density lipoproteins (HDL) to three distinct species: lipid-free apolipoprotein (apo) A-I, neo HDL, a small discoidal HDL-like particle, and a large cholesteryl ester-rich microemulsion (CERM) that contains the cholesterol esters (CE) of up to ∼400000 HDL particles and apo E as its major protein. Similar SOF reaction products are obtained with HDL, total plasma lipoproteins, and whole plasma. We hypothesized that hepatic uptake of CERM-CE via multiple apo E-dependent receptors would be faster than that of HDL-CE. We tested our hypothesis using human hepatoma cells and lipoprotein receptor-specific Chinese hamster ovary (CHO) cells. The uptake of [(3)H]CE by HepG2 and Huh7 cells from HDL after SOF treatment, which transfers >90% of HDL-CE to CERM, was 2.4 and 4.5 times faster, respectively, than from control HDL. CERM-[(3)H]CE uptake was inhibited by LDL and HDL, suggestive of uptake by both the LDL receptor (LDL-R) and scavenger receptor class B type I (SR-BI). Studies in CHO cells specifically expressing LDL-R and SR-BI confirmed CERM-[(3)H]CE uptake by both receptors. RAP and heparin inhibit CERM-[(3)H]CE but not HDL-[(3)H]CE uptake, thereby implicating LRP-1 and cell surface proteoglycans in this process. These data demonstrate that SOF treatment of HDL increases the rate of CE uptake via multiple hepatic apo E receptors. In so doing, SOF might increase the level of hepatic disposal of plasma cholesterol in a way that is therapeutically useful.
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Affiliation(s)
- Baiba K. Gillard
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Corina Rosales
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Biju K. Pillai
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Hu Yu Lin
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Harry S. Courtney
- Veterans Affairs Medical Center and Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38104
| | - Henry J. Pownall
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
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196
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Volynets V, Spruss A, Kanuri G, Wagnerberger S, Bischoff SC, Bergheim I. Protective effect of bile acids on the onset of fructose-induced hepatic steatosis in mice. J Lipid Res 2010; 51:3414-24. [PMID: 20847296 DOI: 10.1194/jlr.m007179] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Fructose intake is being discussed as a key dietary factor in the development of nonalcoholic fatty liver disease (NAFLD). Bile acids have been shown to modulate energy metabolism. We tested the effects of bile acids on fructose-induced hepatic steatosis. In C57BL/6J mice treated with a combination of chenodeoxycholic acid and cholic acid (100 mg/kg body weight each) while drinking water or a 30% fructose solution for eight weeks and appropriate controls, markers of hepatic steatosis, portal endotoxin levels, and markers of hepatic lipogenesis were determined. In mice concomitantly treated with bile acids, the onset of fructose-induced hepatic steatosis was markedly attenuated compared to mice only fed fructose. The protective effects of the bile acid treatment were associated with a downregulation of tumor necrosis factor (TNF)α, sterol regulatory element-binding protein (SREBP)1, FAS mRNA expression, and lipid peroxidation in the liver, whereas hepatic farnesoid X receptor (FXR) or short heterodimer partner (SHP) protein concentration did not differ between groups fed fructose. Rather, bile acid treatment normalized occludin protein concentration in the duodenum, portal endotoxin levels, and markers of Kupffer cell activation to the level of water controls. Taken together, these data suggest that bile acids prevent fructose-induced hepatic steatosis in mice through mechanisms involving protection against the fructose-induced translocation of intestinal bacterial endotoxin.
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Affiliation(s)
- Valentina Volynets
- Department of Nutritional Medicine, University of Hohenheim, Stuttgart, Germany
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197
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Jing Yu, Yumin Xu, Khaoustov V, Yoffe B. Identification of components of grape powder with anti-apoptotic effects. Toxicol Ind Health 2010; 27:19-28. [PMID: 20699283 DOI: 10.1177/0748233710380220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This study is to investigate the mechanism underlying the anti-apoptotic effects of freeze-dried grape powder (FDGP) and identify the polyphenolic compounds involved. We examined apoptotic signaling pathways affected by FDGP and by its active components, including epicatechin, cyanidin, quercetin, and resveratrol, in human Huh7 hepatoma cells by assaying cell viability assays, the activities of caspase 3 and caspase 7, and the expression of endoplasmic reticulum stress-associated proteins. FDGP dramatically decreased taurodeoxycholic acid (TDCA)-induced production of reactive oxygen species (ROS). Assessment of individual active components revealed that at concentrations corresponding to 300 μg/mL FDGP, only quercetin demonstrated cytoprotective effects against mitochondrial-mediated apoptosis. In contrast, increased concentrations of other individual polyphenolic compounds were required to produce measurable cytoprotective effect. Only combinations of all four polyphenolic compounds (epicatechin, cyanidin, quercetin, and resveratrol) restored a degree of the anti-apoptotic effects seen with FDGP. The pretreatment of FDGP at 30 μg/mL concentration could reverse the thapsigargin-induced effects on the expression of endoplasmic reticulum stress-associated proteins. In conclusion, FDGP reduced oxidative stress, endoplasmic reticulum stress, and apoptosis. The mechanisms involved in the anti-apoptotic effects of FDGP included reduced generation of ROS, and reduced processing of certain caspases. We demonstrated that quercetin, epicatechin, and cyanidin are active compounds within FDGP that attenuate apoptosis. These findings contribute to our understanding of the molecular mechanisms of anti-apoptotic and anti-oxidant effects of grape and are expected to assist in developing clinical protocols to treat a variety of stress-mediated conditions.
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Affiliation(s)
- Jing Yu
- Department of Hepatology, Guangxi Traditional Chinese Medical University, Nanning, Guangxi, P R China.
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198
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Cardoso I, Martins D, Ribeiro T, Merlini G, Saraiva MJ. Synergy of combined doxycycline/TUDCA treatment in lowering Transthyretin deposition and associated biomarkers: studies in FAP mouse models. J Transl Med 2010; 8:74. [PMID: 20673327 PMCID: PMC2922089 DOI: 10.1186/1479-5876-8-74] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/30/2010] [Indexed: 12/15/2022] Open
Abstract
Familial Amyloidotic Polyneuropathy (FAP) is a disorder characterized by the extracellular deposition of fibrillar Transthyretin (TTR) amyloid, with a special involvement of the peripheral nerve. We had previously shown that doxycycline administered for 3 months at 40 mg/Kg/ml in the drinking water, was capable of removing TTR amyloid deposits present in stomachs of old TTR-V30M transgenic mice; the removal was accompanied by a decrease in extracellular matrix remodeling proteins that accompany fibrillar deposition, but not of non-fibrillar TTR deposition and/or markers associated with pre-fibrillar deposits. On the other hand, Tauroursodeoxycholic acid (TUDCA), a biliary acid, administrated to the same mouse model was shown to be effective at lowering deposited non-fibrillar TTR, as well as the levels of markers associated with pre-fibrillar TTR, but only at young ages. In the present work we evaluated different doxycycline administration schemes, including different periods of treatment, different dosages and different FAP TTR V30M animal models. Evaluation included CR staining, immunohistochemistry for TTR, metalloproteinase 9 (MMP-9) and serum amyloid P component (SAP). We determined that a minimum period of 15 days of treatment with a 8 mg/Kg/day dosage resulted in fibril removal. The possibility of intermittent treatments was also assessed and a maximum period of 15 days of suspension was determined to maintain tissues amyloid-free. Combined cycled doxycycline and TUDCA administration to mice with amyloid deposition, using two different concentrations of both drugs, was more effective than either individual doxycycline or TUDCA, in significantly lowering TTR deposition and associated tissue markers. The observed synergistic effect of doxycycline/TUDCA in the range of human tolerable quantities, in the transgenic TTR mice models prompts their application in FAP, particularly in the early stages of disease.
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Affiliation(s)
- Isabel Cardoso
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
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199
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Ben Mosbah I, Alfany-Fernández I, Martel C, Zaouali MA, Bintanel-Morcillo M, Rimola A, Rodés J, Brenner C, Roselló-Catafau J, Peralta C. Endoplasmic reticulum stress inhibition protects steatotic and non-steatotic livers in partial hepatectomy under ischemia-reperfusion. Cell Death Dis 2010; 1:e52. [PMID: 21364657 PMCID: PMC3032561 DOI: 10.1038/cddis.2010.29] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During partial hepatectomy, ischemia–reperfusion (I/R) is commonly applied in clinical practice to reduce blood flow. Steatotic livers show impaired regenerative response and reduced tolerance to hepatic injury. We examined the effects of tauroursodeoxycholic acid (TUDCA) and 4-phenyl butyric acid (PBA) in steatotic and non-steatotic livers during partial hepatectomy under I/R (PH+I/R). Their effects on the induction of unfolded protein response (UPR) and endoplasmic reticulum (ER) stress were also evaluated. We report that PBA, and especially TUDCA, reduced inflammation, apoptosis and necrosis, and improved liver regeneration in both liver types. Both compounds, especially TUDCA, protected both liver types against ER damage, as they reduced the activation of two of the three pathways of UPR (namely inositol-requiring enzyme and PKR-like ER kinase) and their target molecules caspase 12, c-Jun N-terminal kinase and C/EBP homologous protein-10. Only TUDCA, possibly mediated by extracellular signal-regulated kinase upregulation, inactivated glycogen synthase kinase-3β. This is turn, inactivated mitochondrial voltage-dependent anion channel, reduced cytochrome c release from the mitochondria and caspase 9 activation and protected both liver types against mitochondrial damage. These findings indicate that chemical chaperones, especially TUDCA, could protect steatotic and non-steatotic livers against injury and regeneration failure after PH+I/R.
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Affiliation(s)
- I Ben Mosbah
- Institut d'Investigacions Biomèdiques de Barcelona-Consejo Superior de Investigaciones Científicas, Barcelona, Spain
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200
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Wang D, Yang L, Huang JM, Wang BY, Li L, Qian W, Ye J, Hou XH. Tauroursodeoxycholic acid inhibits carbon tetrachloride-induced liver fibrosis in rats. Shijie Huaren Xiaohua Zazhi 2010; 18:1979-1984. [DOI: 10.11569/wcjd.v18.i19.1979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine the inhibitory effects of tauroursodeoxycholic acid (TUDCA) on carbon tetrachloride-induced liver fibrosis in rats.
METHODS: A total of 75 healthy Sprague-Dawley rats were randomly divided into five groups: normal control group, model group, low-dose TUDCA group, high-dose TUDCA group and pentoxifylline (PTX) group. Hepatic fibrosis was induced in rats by hypodermic injection of carbon tetrachloride (40%). The low- and high-dose TUDCA groups were orally administered TUDCA at doses of 50 and 100 mg/(kg•d), respectively. The PTX group was orally administered PTX at a dose of 16 mg/(kg•d). The treatment lasted 8 wk for all the groups. Hematoxylin and eosin staining and Masson's trichrome staining of liver tissue was performed for histopathological evaluation of liver fibrosis. Serum parameters of liver fibrosis were detected by enzyme-linked immunosorbent assay. The expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in liver tissue was detected by immunohistochemistry.
RESULTS: Compared with the model group, the levels of serum hyaluronic acid (HA), laminin (LN) and type IV collagen (IV-C) significantly decreased in the low- and high-dose TUDCA groups and the PTX group (HA: 146.33 ± 35.13, 162.2 ± 24.80 and 137.14 ± 22.24 vs 252.83 ± 51.94; LN: 77.20 ± 11.84, 66.80 ± 16.78 and 82.00 ± 10.74 vs 108.00 ± 30.00; IV-C: 14.14 ± 2.59, 12.60 ± 3.17 and 10.09 ± 2.22 vs 25.08 ± 5.93, all P < 0.05). Compared with the model group and normal control group, fibrous septa became thinner and even disappeared, and the number of diffuse cirrhotic nodules and the area of collagen fiber decreased in the TUDCA and PTX intervention groups (all P < 0.05). The expression intensity of TGF-β1 and α-SMA proteins was significantly lower in the TUDCA and PTX intervention groups than in the model group (all P < 0.05), but showed no significant difference between the TUDCA and PTX treatment groups.
CONCLUSION: TUDCA can prevent carbon tetrachloride-induced liver fibrosis in rats by reducing TGF-β1 synthesis, inhibiting hepatic stellate cell activation and decreasing extracellular matrix synthesis.
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