PKC pathway associated with the expression of an A-type K+ channel induced by TGF-β1 in rat vascular myofibroblasts

Our previous study indicated that TGF-β1 induced the expression of a transient outward K+ channel (A-type) during the phenotypic transformation of vascular fibroblasts to myofibroblasts. Here, we studied the relevant signal transduction pathway using whole cell recording and a quantitative RT-PCR technique. Results indicate that the protein kinase C (PKC) agonist phorbol-12-myristate-13-acetate (PMA, 1 μM) could mimic the effect of TGF-β1 (20 ng/ml) on the expression of an A-type K+ channel and induced a similar A-type K+ current. Moreover, a PKC inhibitor, bisindolylmaleimide I (1 μM), could abrogate the effect of TGF-β1 on KV4.2 expression. This result suggests that a PKC pathway may be involved in the expression of an A-type K+ channel induced by TGF-β1 in rat vascular myofibroblasts.