TNF and pulmonary arterial hypertension: To test whether the downregulation of TRPM7 expression in PAH PASMCs is related to the stimulation by PAH stimuli, we cultured the rat normal PASMCs in vitro in medium containing various relevant PAH stimuli, such as 5% fetal calf serum (FCS) or different growth factors and cytokines, including IGF-1, TNF-α or IL-6, all of which have been shown to be pro-hypertensive [44].