RhoA/Rho-kinase triggers epithelial-mesenchymal transition in mesothelial cells and contributes to the pathogenesis of dialysis-related peritoneal fibrosis

Qinglian Wang,Ying Xu,Xiaowei Yang,Zhenwei Shen,Hongxia Cheng,Xiang Liu,Rong Wang,Fajuan Cheng

doi:10.18632/oncotarget.24208

Abstract

Peritoneal fibrosis (PF) with associated peritoneal dysfunction is almost invariably observed in long-term peritoneal dialysis (PD) patients. Advanced glycation end products (AGEs) are pro-oxidant compounds produced in excess during the metabolism of glucose and are present in high levels in standard PD solutions. The GTPase RhoA has been implicated in PF, but its specific role remains poorly understood. Here, we studied the effects of RhoA/Rho-kinase signaling in AGEs-induced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs), and evaluated morphological and molecular changes in a rat model of PD-related PF. Activation of RhoA/Rho-kinase and activating protein-1 (AP-1) was assessed in HPMCs using pull-down and electrophoretic mobility shift assays, respectively, while expression of transforming growth factor-β, fibronectin, α-smooth muscle actin, vimentin, N-cadherin, and E-cadherin expression was assessed using immunohistochemistry and western blot. AGEs exposure activated Rho/Rho-kinase in HPMCs and upregulated EMT-related genes via AP-1. These changes were prevented by the Rho-kinase inhibitors fasudil and Y-27632, and by the AP-1 inhibitor curcumin. Importantly, fasudil normalized histopathological and molecular alterations and preserved peritoneal function in rats. These data support the therapeutic potential of Rho-kinase inhibitors in PD-related PF.

Highlights

Peritoneal dialysis (PD), a life-saving renal replacement strategy for patients with end-stage renal disease, is based on the transcapillary ultrafiltration capacity of the peritoneum, a semi-permeable membrane across which the exchange of waste products and solutes takes place [1, 2]
We studied the effects of RhoA/Rho-kinase signaling in AGEsinduced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs), and evaluated morphological and molecular changes in a rat model of peritoneal dialysis (PD)-related Peritoneal fibrosis (PF)
To assess if RhoA activation is associated with Advanced glycation end products (AGEs) exposure in HPMCs, a RhoA pull-down activation assay was performed after short-term (6 h) treatment with different concentrations of AGEs

Summary

Introduction

Peritoneal dialysis (PD), a life-saving renal replacement strategy for patients with end-stage renal disease, is based on the transcapillary ultrafiltration capacity of the peritoneum, a semi-permeable membrane across which the exchange of waste products and solutes takes place [1, 2]. Continuous exposure to bio-incompatible dialysis solutions often causes repeated episodes of peritonitis, which together with glucose degradation products (GDPs) formed during heat sterilization of the solutions, and advanced glycation end-products (AGEs) produced in the peritoneum from glucose metabolism, cause inflammation and injury to the peritoneal membrane and result in progressive peritoneal fibrosis (PF) and tissue angiogenesis [3,4,5]. These morphological alterations are associated with ultrafiltration failure and increased rates of small-solute transport [3, 6]. Since EMT is associated with pro-fibrotic signaling, it has been ascribed an important role in the development and progression of PF

Methods

Results

Conclusion