title: Melatonin inhibits autophagy and endoplasmic reticulum stress in mice with carbon tetrachloride-induced fibrosis.
abstract: This study aimed to investigate whether inhibition of autophagy and endoplasmic reticulum (ER stress) associates with the antifibrogenic effect of melatonin in mice treated with carbon tetrachloride (CCl4 ). Mice received CCl4 5 μL/g body wt i.p. twice a week for 4 wk or 6 wk. Melatonin was given at 5 or 10 mg/kg/day i.p, beginning 2 wk after the start of CCl4 administration. Treatment with CCl4 resulted in fibrosis evidenced by the staining of α-smooth muscle actin (α-SMA)-positive cells. CCl4 induced an autophagic response measured as the presence of autophagic vesicles, protein 1 light chain 3 (LC3) staining, conversion of LC3-I to autophagosome-associated LC3-II, changes in expression of beclin-1, UV radiation resistance-associated gene (UVRAG), ubiquitin-like autophagy-related (Atg5), Atg12, Atg16L1, sequestosome 1 (p62/SQSTM1), and lysosome-associated membrane protein (LAMP)-2, and increased phosphorylation of the mammalian target of rapamycin (mTOR). There was an increase in the expression of the ER stress chaperones CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin-heavy-chain-binding protein (BiP/GRP78), and 94-kDa glucose-regulated protein (GRP94), and in the mRNA levels of pancreatic ER kinase (PERK), activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), and spliced X-box-binding protein-1 (XBP1). Phospho-IRE1, ATF6, and phospho-PERK protein concentration also increased significantly. Immunohistochemical staining of α-SMA indicated an abrogation of hepatic stellate cells activation by melatonin. Furthermore, treatment with the indole resulted in significant inhibition of the autophagic flux and the unfolded protein response. Findings from this study give new insight into molecular pathways accounting for the protective effect of melatonin in fibrogenesis.
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: San-Miguel
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Crespo
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.
authors.forename: Diana I
authors.initials: DI
authors.lastname: Sánchez
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.
authors.forename: Bárbara
authors.initials: B
authors.lastname: González-Fernández
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Ortiz de Urbina
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain.
authors.forename: María J
authors.initials: MJ
authors.lastname: Tuñón
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: González-Gallego
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D002252:Carbon Tetrachloride Poisoning / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D008550:Melatonin; D051379:Mice
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; C000717248:Hspa5 protein, mouse; D008550:Melatonin
keywords: ER stress; autophagy; carbon tetrachloride; fibrosis; liver; melatonin