Magnesium Regulates Endothelial Barrier Functions through TRPM7, MagT1, and S1P1

Mg²⁺-deficiency is linked to hypertension, Alzheimer's disease, stroke, migraine headaches, cardiovascular diseases, and diabetes, etc., but its exact role in these pathophysiological conditions remains elusive. Mg²⁺ can regulate vascular functions, yet the mechanistic insight remains ill-defined. Data show that extracellular Mg²⁺ enters endothelium mainly through the TRPM7 channel and MagT1 transporter. Mg²⁺ can act as an antagonist to reduce Ca²⁺ signaling in endothelium. Mg²⁺ also reduces the intracellular reactive oxygen species (ROS) level and inflammation. In addition, Mg²⁺-signaling increases endothelial survival and growth, adhesion, and migration. Endothelial barrier integrity is significantly enhanced with Mg²⁺-treatment through S1P1-Rac1 pathways and barrier-stabilizing mediators including cAMP, FGF1/2, and eNOS. Mg²⁺ also promotes cytoskeletal reorganization and junction proteins to tighten up the barrier. Moreover, Mg²⁺-deficiency enhances endothelial barrier permeability in mice, and Mg²⁺-treatment rescues histamine-induced transient vessel hyper-permeability in vivo. In summary, Mg²⁺-deficiency can cause deleterious effects in endothelium integrity, and Mg²⁺-treatment may be effective in the prevention or treatment of vascular dysfunction.