Kim et al reported that the decreased expression of apelin (APLN) in PAH pulmonary arterial endothelial cells (PAECs) down-regulates miR-424/503, which directly suppresses FGF2 and FGFR1 and decreases the phosphorylation of ERK1/2 (Kim et al, 2013). The gene discussed is APLN; the disease is pulmonary arterial hypertension.