Caveolin-1 deficiency induces a MEK-ERK1/2-Snail-1-dependent epithelial-mesenchymal transition and fibrosis during peritoneal dialysis.

Raffaele Strippoli, Jesús Loureiro, Vanessa Moreno, Ignacio Benedicto, María Luisa Pérez Lozano, Olga Barreiro, Teijo Pellinen, Susana Minguet, Miguel Foronda, Maria Teresa Osteso, Enrique Calvo, Jesús Vázquez, Manuel López Cabrera, Miguel Angel del Pozo

Index: EMBO Mol. Med. 7(1) , 102-23, (2015)

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Abstract

Peritoneal dialysis (PD) is a form of renal replacement therapy whose repeated use can alter dialytic function through induction of epithelial-mesenchymal transition (EMT) and fibrosis, eventually leading to PD discontinuation. The peritoneum from Cav1-/- mice showed increased EMT, thickness, and fibrosis. Exposure of Cav1-/- mice to PD fluids further increased peritoneal membrane thickness, altered permeability, and increased the number of FSP-1/cytokeratin-positive cells invading the sub-mesothelial stroma. High-throughput quantitative proteomics revealed increased abundance of collagens, FN, and laminin, as well as proteins related to TGF-β activity in matrices derived from Cav1-/- cells. Lack of Cav1 was associated with hyperactivation of a MEK-ERK1/2-Snail-1 pathway that regulated the Smad2-3/Smad1-5-8 balance. Pharmacological blockade of MEK rescued E-cadherin and ZO-1 inter-cellular junction localization, reduced fibrosis, and restored peritoneal function in Cav1-/- mice. Moreover, treatment of human PD-patient-derived MCs with drugs increasing Cav1 levels, as well as ectopic Cav1 expression, induced re-acquisition of epithelial features. This study demonstrates a pivotal role of Cav1 in the balance of epithelial versus mesenchymal state and suggests targets for the prevention of fibrosis during PD.© 2014 The Authors. Published under the terms of the CC BY 4.0 license.