The present invention provides compositions and methods of using microRNAs to treat pulmonary arterial hypertension. In one aspect, methods are disclosed that are useful for identifying a subject in need of therapeutic intervention to reduce or improve a symptom of pulmonary arterial hypertension, reducing proliferation of pulmonary vascular cells in a subject, or treating pulmonary arterial hypertension in a subject. In another aspect, compositions include an inhibitor of fibroblast growth factor 2 (FGF2) expression comprising at least one of: a mature sequence of miR-424 or miR-503 a pri-miRNA of miR-424 or miR-503 a pre-miRNA of miR-424 or miR-503 and the complement thereof. Pharmaceutical compositions for reducing proliferation of pulmonary vascular cells in a subject in need thereof and biomarker panels are also disclosed.
