Transforming growth factor beta 1 induced endothelin-1 release is peroxisome proliferator-activated receptor gamma dependent in A549 cells.

Shulin Xiang,Yi Zeng,Xia Huang,Liao Pinhu,Yueqiu Qin,Yujie Jiang,Bin Xiong,Weigui Luo,Suren R Sooranna

doi:10.1186/s12950-016-0128-1

Abstract

BackgroundEndothelin-1 (ET-1) is involved in pulmonary vascular remodeling. The aim of this study was to investigate the biochemical interactions between PPAR-γ, TGF-β1 and ET-1 in vitro.MethodsA549 cells were pre-treated with S2505 (10 μM), S2871 (10 μM) with/without SB203580 (10 μM) for 60 min following 2 h treatment with 10 ng/mL TGF-β1. A549 cells were also transfected with positive or negative PPAR-γ plasmids for comparison. RT-PCR, ELISA, western blotting and confocal laser scanning microscopy (CLSM) were used to measure the relevant expression of mRNA, protein, mediators of pathways and nuclear factor translocation.ResultsSB203580 inhibited TGF-β1 induced ET-1 expression in A549 cells. S2871 decreased PPAR-γ mRNA and increase TGF-β1-induced ET-1 expression. S2871 increased phosphorylation of p38 MAPK and Smad2. Cells transfected with PPAR-γ negative plasmid increased TGF-β1 induced ET-1 expression, and increased the expression of phospho-p38 MAPK and phospho-Smad2. S2505 increased PPAR-γ mRNA expression, suppressed the increased TGF-β1-induced expression of ET-1. S2505 inhibited TGF-β1 induced phosphorylation of p38 MAPK and Smad2, also the nuclear translocation of Smad2. Cells transfected with PPAR-γ positive plasmid reduced TGF-β1-induced ET-1 expression, and inhibited the expression of phospho-p38 MAPK and phospho-Smad2.ConclusionsTGF-β1 induced release of endothelin-1 is PPAR-γ dependent in cultured A549 cells.

Highlights

Endothelin-1 (ET-1) is involved in pulmonary vascular remodeling
The results of real-time qPCR demonstrated that 10 ng/mL transforming growth factor beta 1 (TGF-β1), 100 ng/mL BMP-2 and 100 ng/mL BMP-7 increased the relative ET-1 mRNA levels respectively in A549 cells but only the TGF-β1 treatment significantly increased the levels of ET-1 protein expression when measured by enzyme-linked immunosorbent assay (ELISA) (Fig. 1)
SB203580 suppressed the activation of MAPK P38 signal pathway and the expression of ET-1 Confluent A549 cells were treated with 10 ng/mL TGFβ1 or 10 μM SB203580 respectively while cells were pre-treated with 10 μM SB203580 for 60 min before 10 ng/mL TGF-β1 stimulation for the TGF-β1 + SB203580 group

Summary

Introduction

Endothelin-1 (ET-1) is involved in pulmonary vascular remodeling. The aim of this study was to investigate the biochemical interactions between PPAR-γ, TGF-β1 and ET-1 in vitro. Pulmonary arterial hypertension (PAH) is a lifethreatening illness characterized by increased pulmonary vascular resistance (PVR) following right heart dysfunction [1]. The pathogenesis of PAH still remains elusive and there is general agreement that the endothelial dysfunction and pulmonary vascular remodeling appear to be the key prerequisite reasons for the initiation of the disease. Any stimuli leading to vascular endothelial injury, vasoconstriction, cell proliferation, proinflammatory, thrombogenic functions and vascular remodeling are likely to contribute to PAH [7, 8]. The presence of inflammatory cytokines and increased expression of growth and transcriptional factors are thought to contribute directly to further recruitment of inflammatory cells and proliferation of smooth muscle and endothelial cells resulting in increased PVR [9]. ET-1, prostacyclin, TGF-β family and nitric oxide (NO) are closely related to pulmonary arterial smooth muscle cell (PASMC) proliferation [10]

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