Pulmonary hypertension is a disease characterized by pulmonary artery pressure increased, with or without small artery pathological change, which ultimately leads to right heart failure or even death. Pulmonary hypertension seriously threatens to human health, however, the pathogenesis of pulmonary hypertension is unclear. Previous studies have found that bone morphogenetic protein (BMP) signaling system played an important role in the progress of pulmonary hypertension. In the current review, we describe the mechanism of BMP4 in the development of pulmonary hypertension.
ObjectiveTo explore the possibility that GREM1, a bone morphogenetic protein (BMP) antagonist, is a mechanical explanation for BMP signal suppression in congenital heart disease associated pulmonary arterial hypertension (CHD/PAH) patients.MethodsSystemic-to-pulmonary shunt induced PAH was surgically established in rats. At the postoperative 12th week, right heart catheterization and echocardiography evaluation were performed to evaluate hemodynamic indexes and morphology of right heart system. Right heart hypotrophy index and pulmonary vascular remodeling were evaluated. Changes of BMP signal pathway related proteins and GREM1 in lungs and plasma GREM1 concentration were detected. The effect of GREM1 on the proliferation and apoptosis of pulmonary arterial endothelial cells (PAECs) was also explored.ResultsThe hypertensive status was successfully reproduced in rats with systemic-to-pulmonary shunt model. BMP signal pathway was suppressed but GREM1 was up-regulated with no change in hypoxia inducible factor-1 in lungs exposed to systemic-to-pulmonary shunt, while this trend was reversed by systemic-to-pulmonary shunt correction (P<0.05). Immunohistochemical staining demonstrated enhanced staining of GREM1 in remodeled pulmonary arteries. In vitro experiments found that BMP signal was down-regulated but GREM1 expression and secretion were up-regulated in proliferative PAECs (P<0.05). Furthermore, BMP2 significantly inhibited PAECs proliferation and promoted PAECs apoptosis (P<0.05), which could be antagonized by GREM1. In addition, plasma level of GREM1 in rats with systemic-to-pulmonary shunt was also increased and positively correlated with pulmonary hemodynamic indexes.ConclusionSystemic-to-pulmonary shunt induces the up-regulation of GREM1 in lungs, which promotes pulmonary vascular remodeling via antagonizing BMP cascade. These results present a new mechanical explanation for BMP pathway suppression in lungs of CHD/PAH patients.
Pulmonary hypertension is a kind of progressive pulmonary vascular diseases in which there is excessive vasoconstriction and abnormal pulmonary vascular remodeling, and then a gradual increase in pulmonary arterial pressure, and it eventually leads to right ventricular failure and even death. The pathogenesis of pulmonary hypertension is still uncertain, but some studies suggest that Hippo pathway or some components of the Hippo pathway may be involved in the progress of pulmonary hypertension. In this review, we describe the mechanism of the Hippo pathway or some components of the Hippo pathway in the progress of pulmonary hypertension.