title: c-Ski inhibits autophagy of vascular smooth muscle cells induced by oxLDL and PDGF.
abstract: Autophagy is increasingly being recognized as a critical determinant of vascular smooth muscle cell (VSMC) biology. Previously, we have demonstrated that c-Ski inhibits VSMC proliferation stimulated by transforming growth factor β (TGF-β), but it is not clear whether c-Ski has the similar protective role against other vascular injury factors and whether regulation of autophagy is involved in its protective effects on VSMC. Accordingly, in this study, rat aortic A10 VSMCs were treated with 40 µg/ml oxidized low-density lipoprotein (oxLDL) or 20 ng/ml platelet-derived growth factor (PDGF), both of which were autophagy inducers and closely related to the abnormal proliferation of VSMCs. Overexpression of c-Ski in A10 cells significantly suppressed the oxLDL- and PDGF- induced autophagy. This action of c-Ski resulted in inhibiting the cell proliferation, the decrease of contractile phenotype marker α-SMA expression while the increase of synthetic phenotype marker osteopontin expression stimulated by oxLDL or PDGF. Inversely, knockdown of c-Ski by RNAi enhanced the stimulatory effects of oxLDL or PDGF on A10 cell growth and phenotype transition. And further investigation found that inhibition of AKT phosphorylation to downregulate proliferating cell nuclear antigen (PCNA) expression, was involved in the regulation of autophagy and associated functions by c-Ski in the oxLDL- and PDGF-stimulated VSMCs. Collectively, c-Ski may play an important role in inhibiting autophagy to protect VSMCs against some harsh stress including oxLDL and PDGF.
authors.affiliation: Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Zeng
authors.affiliation: Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Yang
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D001343:Autophagy; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D051381:Rats; D015854:Up-Regulation
chemical_list: D008077:Lipoproteins, LDL; D010982:Platelet-Derived Growth Factor; D011518:Proto-Oncogene Proteins; C525545:Ski protein, rat; C099252:oxidized low density lipoprotein