title: Astin B, a cyclic pentapeptide from Aster tataricus, induces apoptosis and autophagy in human hepatic L-02 cells.
abstract: Astins (including astin B) are a class of halogenated cyclic pentapeptides isolated from the medicinal herb of Aster tataricus. However, our previous works showed that the herbal medicine was hepatotoxic in vivo, and a toxicity-guided isolation method led to the identification of a cyclopeptide astin B. Astin B is structurally similar to cyclochlorotine, a well-known hepatotoxic mycotoxin. Thus, the aim of this study was to determine the potential cytotoxic effects and the underlying mechanism of astin B on human normal liver L-02 cells. We found that astin B has hepatotoxic effects in vitro and in vivo and that hepatic injury was primarily mediated by apoptosis in a mitochondria/caspase-dependent manner. Astin B provoked oxidative stress-associated inflammation in hepatocytes as evidenced by increased levels of reactive oxygen species (ROS), reduced contents of intracellular glutathione (GSH), and enhanced phosphorylation of c-Jun N-terminal kinase (JNK). Furthermore, the mitochondria-dependent apoptosis was evidenced by the depolarization of the mitochondrial membrane potential, the release of cytochrome c into cytosol, the increased ratio of Bax/Bcl-2, and the increased activities of caspases-9 and -3. Interestingly, astin B treatment also induces autophagy in L-02 cells, characterized by acidic-vesicle fluorescence, increased LC3-II and decreased p62 expression. Autophagy is a protective mechanism that is used to protect cells from apoptosis. The presence of autophagy is further supported by the increased cytotoxicity and the enhanced cleaved caspase-3 after co-treatment of cells with an autophagy inhibitor, also by increased LC3-II and decreased p62 after co-treatment with a caspase inhibitor. Taken together, astin B, most likely together with other members of astins, is the substance that is primarily responsible for the hepatotoxicity of A.tataricus.
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Ming-Dan
authors.initials: MD
authors.lastname: Li
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Pei-Pei
authors.initials: PP
authors.lastname: Cao
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China. Electronic address: njchaofeng@126.com.
authors.forename: Chao-Feng
authors.initials: CF
authors.lastname: Zhang
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Huang
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Xiang-Hong
authors.initials: XH
authors.lastname: Xu
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China.
authors.forename: Bao-Lin
authors.initials: BL
authors.lastname: Liu
authors.affiliation: Research Department of Pharmacognosy, China Pharmaceutical University, Longmian Road 639, Nanjing 211198, PR China. Electronic address: mianzhang@126.com.
authors.forename: Mian
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D031173:Aster Plant / Q000633:toxicity*; D001343:Autophagy / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D056486:Chemical and Drug Induced Liver Injury / Q000378:metabolism / Q000473:pathology; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010456:Peptides, Cyclic / Q000737:chemistry / Q000633:toxicity*; D010946:Plants, Medicinal / Q000633:toxicity*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism
chemical_list: D010456:Peptides, Cyclic; D019253:Proto-Oncogene Proteins c-bcl-2; C082414:astin B; D020169:Caspases
keywords: Apoptosis; Aster tataricus; Astin B; Autophagy; Liver injury