title: Autophagy protects against cholesterol-induced apoptosis in pancreatic β-cells.
abstract: Autophagy is believed to play an important role in maintaining homeostasis in pancreatic β-cells during insulin resistance. This study investigated the role of autophagy in β-cell damage induced by cholesterol and its possible activation mechanism. Rat and mouse pancreatic β-cell lines INS-1 and βTC-6 were incubated with cholesterol alone or in combination with autophagy inhibitors E-64d/Pepstatin A or bafilomycin A1. DAPI staining, western blotting, transmission electron microscopy and immunofluorescence were conducted to assess the effects of autophagy inhibitors on cholesterol-induced apoptosis and autophagy activity. An increase in FITC-LC3 fluorescence dots, autophagic vacuoles and LC3-II protein indicated that autophagy was activated in cells treated with cholesterol. This was further confirmed by blocking the natural turnover processes in lysosomes and autolysosomes with autophagy inhibitors, suggesting enhanced autophagic activity rather than blockage of autophagy. Furthermore, inhibition of autophagy significantly augmented the activation of caspase 3 and the percentage of cholesterol-induced apoptotic nuclei. These results demonstrate that autophagy plays a protective role against cholesterol-induced apoptosis in pancreatic β-cells.
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Jiahua
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Feijuan
authors.initials: F
authors.lastname: Kong
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Pan
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Du
authors.affiliation: Intensive Care Unit, Hang Gang Hospital, Hangzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ye
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Fenping
authors.initials: F
authors.lastname: Zheng
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China. Electronic address: zjq8866@zju.edu.cn.
authors.forename: Jiaqiang
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D006706:Homeostasis; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism; D018942:Macrolides / Q000737:chemistry; D051379:Mice; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010436:Pepstatins / Q000737:chemistry; D051381:Rats; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D018942:Macrolides; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D010436:Pepstatins; C040929:bafilomycin A1; D002784:Cholesterol; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D053148:Caspase 3; C031375:pepstatin
keywords: Apoptosis; Autophagy; Cholesterol; LC3-II; β-cell