title: Apelin suppresses apoptosis of human vascular smooth muscle cells via APJ/PI3-K/Akt signaling pathways.
abstract: Apoptosis of vascular smooth muscle cells (VSMCs) plays an important role in regulating vascular remodeling during cardiovascular diseases. Apelin is the endogenous ligand for the G-protein-coupled receptor APJ and plays an important role in the cardiovascular system. However, the mechanisms of apelin on apoptosis of VSMCs have not been elucidated. Using a culture of human VSMCs as a model for the study of apoptosis, the relationship between apelin and apoptosis of human VSMCs and the signal pathway involved were investigated. Using western blotting, we confirmed that VSMCs could express APJ. To evaluate the possible role of apelin in VSMC apoptosis, we assessed its effect on apoptosis of human VSMCs. The results showed that apelin inhibited human VSMCs apoptosis induced by serum deprivation. Suppression of APJ with small-interfering RNA (siRNA) abolished the anti-apoptotic activity of apelin. Apelin increased Bcl-2 protein expression, but decreased Bax protein expression. An increase in activation of extracellular signal-regulated protein kinase (ERK) and Akt (a downstream effector of phosphatidylinositol 3-kinase) was shown after apelin stimulation. Suppression of APJ with siRNA abolished the apelin-induced activation of ERK and Akt. LY294002 (a PI3-K inhibitor) blocked apelin-induced activation of Akt and abolished the apelin-induced antiapoptotic activity. Our study suggests that apelin suppresses serum deprivation-induced apoptosis of human VSMCs, and that the anti-apoptotic action is mediated through the APJ/PI3-K/Akt signaling pathways.
authors.affiliation: Department of Pediatrics, The Second Xiang-Ya Hospital, Central South University, Changsha, 410011, Hunan, People's Republic of China.
authors.forename: Rong-Rong
authors.initials: RR
authors.lastname: Cui
authors.forename: Ding-An
authors.initials: DA
authors.lastname: Mao
authors.forename: Lu
authors.initials: L
authors.lastname: Yi
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Xing-Xing
authors.initials: XX
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.forename: Xian-Ping
authors.initials: XP
authors.lastname: Wu
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Liao
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.forename: Ji-Cai
authors.initials: JC
authors.lastname: Meng
authors.forename: Ling-Qing
authors.initials: LQ
authors.lastname: Yuan
authors.forename: Er-Yuan
authors.initials: EY
authors.lastname: Liao
mesh_terms: D000818:Animals; D000073861:Apelin; D017209:Apoptosis; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C115436:APLN protein, human; D000073861:Apelin; D036341:Intercellular Signaling Peptides and Proteins; D043562:Receptors, G-Protein-Coupled; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt