MCTP2 and pulmonary arterial hypertension: CircST6GAL1 deficiency reversed hypoxia‐induced proliferation and migration, as well as apoptosis arrest in HPASMCs, and alleviated pulmonary vascular remodeling in MCT‐induced PAH mouse models through the miR‐509‐5p/MCTP2 axis, indicating a potential therapeutic target for PAH.