Mibefradil suppresses the proliferation of pulmonary artery smooth muscle cells

作者:Li, Hong-Hong; Xie, Li-Jian; Xiao, Ting-Ting; Huang, Min; Shen, Jie*
来源:Journal of Investigative Medicine, 2016, 64(1): 45-49.
DOI:10.1136/jim-d-15-00167

摘要

Intracellular Ca2+ levels play a critical role in the regulation of vasodilation and vasoconstriction by stimulating pulmonary artery smooth muscle cell (PASMC) proliferation, which is important in the pathogenesis of pulmonary arterial hypertension (PAH); however, L-type Ca2+ channel antagonists are useful in only few patients with PAH. The present study sought to assess the effect of mibefradil, which blocks T-type Ca2+ channels, on PASMC proliferation and Ca2+ channel profile. Human PASMCs were stimulated with 25ng/mL platelet-derived growth factor-BB (PDGF-BB) with and without 10 mu M mibefradil or 100nM sildenafil. After 48 or 72h, PASMC proliferation and Ca2+ channel expression were assessed by MTT assays and western blot analysis, respectively. PDGF-BB-induced PASMC proliferation at 72h (p<0.01), which was inhibited by both sildenafil and mibefradil (p<0.01). Transient receptor potential Ca2+ channel 6 (TRPC6) expression was significantly increased with PDGF-BB stimulation (p=0.009); however, no changes in TRPC1, TRPC3, CAV1.2, and CAV3.2 levels were observed. Although both TRPC1 and CAV1.2 expression levels were increased in PDGF-stimulated PASMCs on mibefradil and sildenafil treatment, it was not statistically significant (p=0.086 and 1.000, respectively). Mibefradil inhibits PDGF-BB-stimulated PASMC proliferation; however, the mechanism through which it functions remains to be determined. Further studies are required to elucidate the full therapeutic value of mibefradil for PAH.