Taken together, we showed that PASMCs from monocrotaline-induced pulmonary artery remodeling are different from the normal controls in their microRNA repertoire, and miR-26b, a microRNA significantly downregulated in pulmonary artery remodeling, contributes to the development of PAH via releasing the inhibition of its two target genes, CTGF and CCND1, both of which have been repeatedly reported to be involved in the pathogenesis of the disease. The gene discussed is CCN2; the disease is pulmonary arterial hypertension.