Rho kinase and Na⁺ /H⁺ exchanger mediate endothelin-1-induced pulmonary arterial smooth muscle cell proliferation and migration

Abstract

Excessive production of endothelin‐1 (ET‐1) has been observed in almost all forms of pulmonary hypertension. ET‐1, a highly potent vasoconstrictor, can also potentiate pulmonary arterial smooth muscle cell (PASMC) growth and migration, both of which contribute to the vascular remodeling that occurs during the development of pulmonary hypertension. Increasing evidence indicates that alkalinization of intracellular pH (pH i), typically due to activation of Na+/H+ exchange (NHE), is associated with enhanced PASMC proliferation and migration. We recently demonstrated that application of exogenous ET‐1 increased NHE activity in murine PASMCs via a mechanism requiring Rho kinase (ROCK). However, whether ROCK and/or increased NHE activity mediate ET‐1‐induced migration and proliferation in PASMCs remains unknown. In this study, we used fluorescent microscopy in transiently cultured PASMCs from distal pulmonary arteries of the rat and the pH‐sensitive dye, BCECF‐AM, to measure changes in resting pH i and NHE activity induced by exposure to exogenous ET‐1 (10−8 mol/L) for 24 h. Cell migration and proliferation in response to ET‐1 were also measured using Transwell assays and BrdU incorporation, respectively. We found that application of exogenous ET‐1 had no effect on NHE1 expression, but increased pH i, NHE activity, migration, and proliferation in rat PASMCs. Pharmacologic inhibition of NHE or ROCK prevented the ET‐1‐induced changes in cell function (proliferation and migration). Our results indicate that ET‐1 modulates PASMC migration and proliferation via changes in pH i homeostasis through a pathway involving ROCK.

The Role and Regulation of Pulmonary Artery Smooth Muscle Cells in Pulmonary Hypertension

“…Endothelin is secreted by endothelial cells and has three isoforms, among which endothelin-1 (ET-1) is the most widely expressed and mediates vascular contraction, cell migration, and proliferation. In terms to PASMC, ET-1 binds to ET A or ET B and then has an impact on decreased K + channels, elevated intracellular Ca 2+ , and activation of NHE1 and Rho kinase (ROCK) signaling, leading to the migration and proliferation of PASMC [85][86][87][88].…”

MicroRNA‑153 attenuates hypoxia‑induced excessive proliferation and migration of pulmonary arterial smooth muscle cells by targeting ROCK1 and NFATc3

“…The above data confirmed that miR-153 exhibited preventive potential in the proliferation and migration of HPASMCs induced by hypoxia, although the targets of miR-153 remained elusive. ROCK1 and NFATc3 are important therapeutic targets for PAH and they are activated and involved in the modulation of cell proliferation and migration in PAH ( 46 , 47 ). Therefore, an in-depth analysis was conducted using TargetScan to determine whether NFATc3 and ROCK1 are the target genes of miR-153.…”

Comprehensive Analyses of miRNA-mRNA Network and Potential Drugs in Idiopathic Pulmonary Arterial Hypertension

“…Among them, endothelin-1 (EDN1) is a potent vasoconstrictor and its receptors are therapeutic targets in the treatment of PAH [ 23 , 24 ]. It was able to promote contraction via increasing intracellular Ca 2+ and increasing PASMC proliferation and migration, leading to vascular remodeling, which is a key mechanism underlying PAH [ 25 – 27 ]. Vascular cell adhesion molecule 1 (VCAM1), an adhesion molecule mediating leukocyte transmigration and increasing tissue inflammation [ 28 ], was found to increase in both patients and animal models of IPAH [ 29 , 30 ].…”