MCTP2 and pulmonary arterial hypertension: Hence, this study used hypoxia‐induced human pulmonary artery SMCs (HPASMCs) in vitro and established monocrotaline (MCT)‐induced PAH mice in vivo to investigate the action of circST6GAL1 on PAH and further explored whether circST6GAL1 functioned by regulating miR‐509‐5p and MCTP2.