5-HT promotes pulmonary arterial smooth muscle cell proliferation through the TRPC channel.

Pulmonary arterial hypertension is caused by an imbalance of pulmonary vasoconstriction and vasodilation. Pulmonary arteriolar remodeling is a primary pathological change and proliferation of pulmonary arterial smooth muscle cells (PASMC) is an important pathological basis for pulmonary arteriolar remodeling. Vasoactive substances, such as 5-HT, may play a role in proliferation of PASMC via unknown mechanisms. In vitro experiments with PASMC showed that the TRPC channel inhibitor SKF96365 inhibited the effects 5-HT and DOI on PASMC proliferation and G2M percentage increase, and decreased expression of TRPC1, TRPC6 and calcineurin A/NFATc3 induced by 5-HT and DOI. SKF96365 inhibited binding of NFATc3 and DNA promoted by 5-HT and DOI. Therefore, 5-HT may affect the TRPC channel to promote proliferation of PASMC; upregulate expression of TRPC1, TRPC6, and calcineurin A/NFATc3; and therefore promote NFATc3 nuclear translocation. There may be crosstalk between 5-HT and TRPC, which may contribute to the pathogeneis of pulmonary arterial hypertension and this may be a novel therapeutic target for treating pulmonary arterial hypertension.