Our data from the primary culture of PASMCs of rats with PAH showed that circDiaph3 plays an important role in promoting the proliferation of PASMCs through insulin-like growth factor 1 receptor (IGF1R) and phosphatidylinositol-3-kinase/protein kinase B/mammalian target of Rapamycin (PI3K/AKT/mTOR) signaling pathway. The gene discussed is IGF1R; the disease is pulmonary arterial hypertension.