Platelet-derived Growth Factor Regulates The Phenotypic Transition Of Corpus Cavernosum Smooth Muscle Through PDGFR/STAT3 Signaling Pathway In Rats

Objective Erectile dysfunction(ED)is a common clinical disease that is difficult to treat.We previously found that hypoxia modulates the phenotype of primary corpus cavemosum smooth muscle cells(CCSMCs)in rats,but the underlying molecular mechanism is still unknown.Platelet-derived growth factor receptor(PDGFR)-related signaling pathways are correlated with cell phenotypic transition,but research has been focused more on vascular smooth muscle and tracheal smooth muscle and less on CCSMCs.Here,we investigated the role of PDGFR-related signaling pathways in penile CCSMCs.Methods We used the type I collagenase to isolate the CCSMCs from rats and cultured in vitro.Gradient PDGF-BB were treated in CCSMC and then observed the changes of morphology and phenotype.In addition,we inhibite the activity of PDGFR via siRNA or the PDGFR inhibitor crenolanib and treatd with PDGF-BB and then observed the changes of phenotypic proteins.Moreover,we use signal transducer and activator of transcription-3(STAT3)and serine-threonine protein kinase(AKT)siRNA to downregulate the signaling pathways downstream of PDGFR and then treat with PDGF-BB and observed the changes of phenotypic proteins.Finally,we used the lentiviral transfection to over express STAT3 in CCSMC cells and then treat with crenolanib and PDGF-BB.Result We successfully isolated the CCSMCs from rats and cultured in vitro.PDGF-BB at 5,10,or 20 ng/ml altered CCSMCs morphology from the original elongated,spindle shape to a broader shape and promoted the synthetic phenotype and expression of the related proteins vimentin and collagen-I,while inhibiting the contractile phenotype and expression of the related proteins smooth muscle(SM)a-actin(a-SMA)and desmin.Inhibition of PDGFR activity via siRNA or the PDGFR inhibitor crenolanib inhibited vimentin and collagen-1 expression,increased a-SMA and desmin expression,and considerably inhibited serine-threonine protein kinase(AKT)and signal transducer and activator of transcription 3(STAT3)phosphorylation.STAT3 knockdown promoted the contractile phenotype,inhibited vimentin and collagen-I expression,and increased a-SMA and desmin expression,whereas AKT knockdown did not affect phenotype-associated proteins.STAT3 overexpression in CCSMC cells weakened the suppressive effect of PDGFR inhibition on the morphology and phenotypic transformation induced by PDGF-BB.Conclusion PDGF promoted the synthetic phenotype transition through activation of the PDGFR/STAT3 signaling pathway.Thus,regulation of this pathway might contribute to ED therapy.