Cx43在模拟失重致血管平滑肌细胞表型转换中的作用OA

Objective To investigate the effects of connexin 43(Cx43)on phenotypic switching of vascular smooth muscle cells under simulated microgravity.Methods Human arterial smooth muscle cells(HASMCs)were cultured under simulated microgravity by a cell stress-loading culture system and randomly divided into normal gravity group(NC group)and simulated microgravity group(SMG group).After 96 h of cyclic stretch,differential proteins were screened by mass spectrometry.Expression of α-smooth muscle actin(α-SMA)and smooth muscle protein 22-α(SM22α),osteopontin(OPN)and Cx43 in HASMCs was determined by Western blotting,and their migratory capacity was evaluated with Transwell assays.Following the construction of Cx43 knockdown cells using shRNA lentiviral vectors and a subsequent 96-hour cyclic stretch,their function was assessed.Results Proteomic profiling revealed that compared with the NC group,SMG group significantly down-regulated contractile proteins ACTA2 and TAGLN,while up-regulating migration-related proteins LPAR1,TGFBR1,PDGFD,and GJA1.Moreover,they were significantly enriched in positive regulators of cell migration and cytokine-cytokine interaction.Further experimental results showed that compared with the NC group,the levels of α-SMA and SM22α in HASMCs of the SMG group were markedly decreased(P<0.05),the expression of OPN was significantly increased(P<0.05),and the number of migrating cells increased significantly(P<0.05).Cx43 mRNA and protein levels in HASMCs of the SMG group were also significantly higher than those of the NC group(P<0.05).Knockdown of Cx43 significantly increased α-SMA and SM22α expression(P<0.05),and significantly reduced OPN levels(P<0.05)in the SMG group.The results of the Transwell aassay indicated that knockdown of Cx43 could inhibit the migration ability of HASMCs.Conclusion Simulated microgravity promotes smooth muscle cells phenotypic switching and migratory capacity via a Cx43-dependent pathway.