[Pulmonary hypertension: microRNAs in pathogenesis, diagnosis and therapy]

Whereas pulmonary arterial hypertension is an orphan disease, the term pulmonary hypertension includes several common entities and is of major clinical significance. The pathophysiological triad of vasoconstriction, microthrombosis and vascular remodeling is found in most forms of pulmonary hypertension, independently of the underlying etiology. In this review, novel aspects in the pathogenesis of the remodeling, in particular microRNAs, will be discussed. MicroRNAs are small RNA fragments which bind specifically to the mRNA of a target gene thus decreasing its stability or inhibiting further translation ("gene silencing"). Of major interest is the association between microRNAs and the expression of bone morphogenetic protein receptor type II which has been found to be dysregulated on pulmonary endothelial and vascular smooth muscle cells in several forms of pulmonary hypertension. The specific inhibition of microRNAs by antagomiRs makes microRNAs a potential therapeutic target. Moreover, microRNAs are being validated in serum as biomarkers for diagnosis, severity and prognosis of pulmonary hypertension.