Endothelial Dysfunction Following Enhanced TMEM16A Activity in Human Pulmonary Arteries

Davor Skofic Maurer,Horst Olschewski,Neha Sharma,Andrea Olschewski,Péter Enyedi,Saša Frank,Miklós Lengyel,Walter Klepetko,Grazyna Kwapiszewska,Diana Zabini,Elisabeth Gschwandtner,Bence M Nagy,Chandran Nagaraj

doi:10.3390/cells9091984

Abstract

Endothelial dysfunction is one of the hallmarks of different vascular diseases, including pulmonary arterial hypertension (PAH). Ion channelome changes have long been connected to vascular remodeling in PAH, yet only recently has the focus shifted towards Ca2+-activated Cl− channels (CaCC). The most prominent member of the CaCC TMEM16A has been shown to contribute to the pathogenesis of idiopathic PAH (IPAH) in pulmonary arterial smooth muscle cells, however its role in the homeostasis of healthy human pulmonary arterial endothelial cells (PAECs) and in the development of endothelial dysfunction remains underrepresented. Here we report enhanced TMEM16A activity in IPAH PAECs by whole-cell patch-clamp recordings. Using adenoviral-mediated TMEM16A increase in healthy primary human PAECs in vitro and in human pulmonary arteries ex vivo, we demonstrate the functional consequences of the augmented TMEM16A activity: alterations of Ca2+ dynamics and eNOS activity as well as decreased NO production, PAECs proliferation, wound healing, tube formation and acetylcholine-mediated relaxation of human pulmonary arteries. We propose that the ERK1/2 pathway is specifically affected by elevated TMEM16A activity, leading to these pathological changes. With this work we introduce increased TMEM16A activity in the cell membrane of human PAECs for the development of endothelial dysfunction in PAH.

Highlights

Endothelial cells form a barrier, effectively separating the luminal from the abluminal side of the vessels and responding to a variety of cues coming from continuous intercellular communication, both locally and systemically
Posttranslational modifications and decreased K+ channel expression have been described in idiopathic pulmonary arterial hypertension (PAH) (IPAH) pulmonary arterial smooth muscle cells (PASMCs) and animal models of PH, linking membrane depolarization to opening of voltage-gated Ca2+ channels (VGCC), promoting the constrictive and proliferative phenotype as seen in PAH [6,7,8,9]
Our results showed significantly increased Bbr-sensitive current in IPAH

Summary

Introduction

Endothelial cells form a barrier, effectively separating the luminal from the abluminal side of the vessels and responding to a variety of cues coming from continuous intercellular communication, both locally and systemically. They function as an endocrine organ, releasing a diverse array of compounds affecting vasoactive, immune, growth and coagulation processes [1,2]. This makes the endothelium in pulmonary arterial hypertension (PAH) a perfectly positioned critical source of mediators promoting vascular remodeling, e.g., serotonin (5-HT), vasoactive peptides (NO, PGI2, ET-1), cytokines, chemokines, and growth factors [3]. Transient receptor potential (TRP) channels were likewise shown to be dysregulated in IPAH PASMCs demonstrating their role in the phenotypic switch [10]

Methods

Results

Conclusion