Acidic organelles mediate TGF-\u03b21-induced cellular fibrosis via (pro)renin receptor and vacuolar ATPase trafficking in human peritoneal mesothelial cells

Ikuko Oba-Yabana,Kazuhito Totsune,Yusuke Ohsaki,Geneviève Nguyen,Takuo Hirose,Rémi Piedagnel,Pierre M Ronco,Chika Takahashi,Sadayoshi Ito,Emiko Sato,Takefumi Mori,Satoshi Kinugasa,Yoshikazu Muroya

doi:10.1038/s41598-018-20940-x

Abstract

TGF-β1, which can cause renal tubular injury through a vacuolar-type H+-ATPase (V-ATPase)-mediated pathway, is induced by the glucose degradation product methylglyoxal to yield peritoneal injury and fibrosis. The present study investigated the roles of V-ATPase and its accessory protein, the (pro)renin receptor, in peritoneal fibrosis during peritoneal dialysis. Rats daily administered 20 mM methylglyoxal intraperitoneally developed significant peritoneal fibrosis after 7 days with increased expression of TGF-β and V-ATPase, which was reduced by the inhibition of V-ATPase with co-administration of 100 mM bafilomycin A1. The (pro)renin receptor and V-ATPase were expressed in acidic organelles and cell membranes of human peritoneal mesothelial cells. TGF-β1 upregulated the expression of collagens, α-SMA, and EDA-fibronectin, together with ERK1/2 phosphorylation, which was reduced by inhibition of V-ATPase, (pro)renin receptor, or the MAPK pathway. Fibronectin and the soluble (pro)renin receptor were excreted from cells by acidic organelle trafficking in response to TGF-β1; this excretion was also suppressed by inhibition of V-ATPase. Soluble (pro)renin receptor concentrations in effluents of patients undergoing peritoneal dialysis were associated with the dialysate-to-plasma ratio of creatinine. Together, these results demonstrate a novel fibrosis mechanism through the (pro)renin receptor and V-ATPase in the acidic organelles of peritoneal mesothelial cells.

Highlights

Peritoneal dialysis (PD) comprises a renal replacement therapy with many unique advantages;[1] peritoneal fibrosis in patients undergoing long-term PD alters peritoneal function and limits the PD treatment period[2]
Intraperitoneal administration of the V-ATPase inhibitor bafilomycin A1 (BAF) significantly attenuated MG-induced thickening, indicating that V-ATPase was responsible for the MG-mediated peritoneal fibrosis
Broad expression of TGF-β123, α-SMA (Acta), Fibronectin (Fn1), Atp6v0c, and Atp6v1b1/2 was observed in the visceral peritoneal membrane fibrotic submesothelial compact zone, which was inhibited by BAF (Fig. 1B)

Summary

Introduction

Peritoneal dialysis (PD) comprises a renal replacement therapy with many unique advantages;[1] peritoneal fibrosis in patients undergoing long-term PD alters peritoneal function and limits the PD treatment period[2]. The. Transforming Growth Factor-β1 (TGF-β1) functions as a strong mediator of peritoneal fibrosis and cellular injury in human peritoneal mesothelial cells (HPMCs)[13,14]. We hypothesised that (P)RR and V-ATPase are expressed in HPMCs and involved in MG and TGF-β1-induced peritoneal fibrosis. To test this hypothesis, we first determined V-ATPase expression and role in the submesothelial compact zone of rats administered MG in the peritoneal cavity. (P)RR and V-ATPase expression were examined in the organelles of HPMCs. Third, the functional roles of these molecules were determined in acidic organelles and cell fibrosis. The role of s(P)RR was examined in the peritoneum of patients with chronic kidney disease (CKD) undergoing PD

Methods

Results

Conclusion