PDE5A and pulmonary arterial hypertension: We show that miR‐30d is significantly reduced in plasma from PAH patients and has protective effect against PAH and pulmonary vascular remodeling through targeting metadherin (MTDH) and phosphodiesterase 5A (PDE5A), and identify nuclear respiratory factor 1 (NRF1) as an upstream regulator of miR‐30d.