PDGF-mediated PI3K/AKT/β-catenin Signaling Regulates Gap Junctions In Corpus Cavernosum Smooth Muscle Cells

Objective Erectile dysfunction(ED)is the most common sexual disorder that men report to healthcare providers.Gap junctions(GJs)are thought to be responsible for synchronous shrinkage of corpus cavernosum smooth muscle cells(CCSMCs),and play thus an important role in the maintenance of an erection.Hypoxia has been suggested as an potential pathological mechanism underlying ED.Hypoxia increases the expression of platelet derived growth factor(PDGF)which also enhances the main GJ component connexin(Cx)43 in CCSMCs.However,the potential molecule mechanism between them is still unclear.In my paper,signal path by which PDGF induce Cx43 alteration has been studied.Thus,targeting this pathway is a potential therapeutic strategy for the treatment of ED.Methods 1.CCSMCs cultures.2.Immunofluorescence analysis of CCSMCs.3.Endothelial SMC co-culture model.4.Hypoxia treatment.5.scrape-loading and dye transfer.6.Detection signal path proteins by western blot.7.Enzyme-linked immunosorbent assay(ELISA)for PDGF.8.In vitro PDGFR inhibition assay.9.In vitro PI3 K activation/inhibition assay.10.β-catenin RNA interference assay.11.Statistical analysisResults(1)Hypoxia increased the expression of platelet-derived growth factor(PDGF)and the main GJ component Cx43 in CCSMCs.(2)Inhibiting PDGF receptor(PDGFR)activity decreased Cx43 expression.(3)Treatment with different concentrations of PDGF increased the levels of phosphorylated protein kinase B(AKT),β-catenin,and Cx43.(4)whereas inhibition of PDGFR or activation of phosphatidylinositol 3 kinase(PI3K)/AKT signaling altered β-catenin and Cx43 expression.(5)Meanwhile,silencing β-catenin resulted in the downregulation of Cx43.Conclusion PDGF secretion by CCSMCs and vascular endothelial cells is enhanced under hypoxic conditions,leading to increased Cx43 expression through PI3K/AKT/β-catenin signaling and ultimately affecting GJ function in ED.