In the past 5 years, miR-23a has been found to be a biomarker for idiopathic PH [35] and a possible therapeutic target for pulmonary arterial hypertension because it promotes cell proliferation and migration by targeting the BMPR2/Smad1 signal in hypoxia-induced PASMCs [36]. The gene discussed is SMAD1; the disease is pulmonary arterial hypertension.