TGF-β1 inhibits connexin-43 expression in cultured smooth muscle cells of human bladder

ObjectiveIn this research, we studied the TGF-β1 effects on connexin-43 expression in cultured human bladder smooth muscle cells.MethodsHuman bladder smooth muscle cells primary cultures, with bladder tissue obtained from patients undergoing cystectomy, were intervened by recombinant human TGF-β1. Connexin-43 expression in human bladder smooth muscle cells was then examined by Western blotting and immunocytochemistry.ResultsStimulation with TGF-β1 led to significant reduction of connexin-43 immunoreactivity and coupling (P<0.0001). Connexin-43 protein expression was significantly downregulated (P<0.05). Simultaneously, low phosphorylation species of connexin-43 were particularly affected.ConclusionOur experiments demonstrated a significant downregulation of connexin-43 by TGF-β1 in cultured human bladder smooth muscle cells. These findings support the view that TGF-β1 is involved in the pathophysiology of urinary bladder dysfunction.