Magnesium Supplementation Attenuates Pulmonary Hypertension via Regulation of Magnesium Transporters

Pulmonary hypertension (PH) is characterized by profound vascular remodeling and altered Ca 2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Magnesium ion (Mg 2+ ), a natural Ca 2+ antagonist and a cofactor for numerous enzymes, is crucial for regulating diverse cellular functions, but its roles in PH remains unclear. Here, we examined the roles of Mg 2+ and its transporters in PH development. Chronic hypoxia and monocrotaline induced significant PH in adult male rats. It was associated with a reduction of [Mg 2+ ] i in PASMCs, a significant increase in gene expressions of Cnnm2 , Hip14 , Hip14l , Magt1 , Mmgt1 , Mrs2 , Nipa1 , Nipa2 , Slc41a1 , Slc41a2 and Trpm7 ; upregulation of SLC41A1, SLC41A2, CNNM2, and TRPM7 proteins; and downregulation of SLC41A3 mRNA and protein. Mg 2+ supplement attenuated pulmonary arterial pressure, right heart hypertrophy, and medial wall thickening of pulmonary arteries, and reversed the changes in the expression of Mg 2+ transporters. Incubation of PASMCs with a high concentration of Mg 2+ markedly inhibited PASMC proliferation and migration, and increased apoptosis, whereas a low level of Mg 2+ produced the opposite effects. siRNA targeting Slc41a1/2, Cnnm2, and Trpm7 attenuated PASMC proliferation and migration, but promoted apoptosis; and Slc41a3 overexpression also caused similar effects. Moreover, siRNA targeting Slc41a1 or high [Mg 2+ ] incubation inhibited hypoxia-induced upregulation and nuclear translocation of NFATc3 in PASMCs. The results, for the first time, provide the supportive evidence that Mg 2+ transporters participate in the development of PH by modulating PASMC proliferation, migration, and apoptosis; and Mg 2+ supplementation attenuates PH through regulation of Mg 2+ transporters involving the NFATc3 signaling pathway.