Epithelial-Mesenchymal Transition in Kidney Tubular Epithelial Cells Induced by Globotriaosylsphingosine and Globotriaosylceramide.

Yeo Jin Jeon,Namhee Jung,Joo-Won Park,Hae-Young Park,Sung-Chul Jung,Jung Weon Lee

doi:10.1371/journal.pone.0136442

Abstract

Fabry disease is a lysosomal storage disorder caused by deficiency of alpha-galactosidase A (α-gal A), which results in the deposition of globotriaosylceramide (Gb3) in the vascular endothelium. Globotriaosylsphingosine (lyso-Gb3), a deacylated Gb3, is also increased in the plasma of patients with Fabry disease. Renal fibrosis is a key feature of advanced Fabry disease patients. Therefore, we evaluated the association of Gb3 and lyso-Gb3 accumulation and the epithelial–mesenchymal transition (EMT) on tubular epithelial cells of the kidney. In HK2 cells, exogenous treatments of Gb3 and lyso-Gb3 increased the expression of TGF-β, EMT markers (N-cadherin and α-SMA), and phosphorylation of PI3K/AKT, and decreased the expression of E-cadherin. Lyso-Gb3, rather than Gb3, strongly induced EMT in HK2 cells. In the mouse renal mesangial cell line, SV40 MES 13 cells, Gb3 strongly induced phenotype changes. The EMT induced by Gb3 was inhibited by enzyme α-gal A treatment, but EMT induced by lyso-Gb3 was not abrogated by enzyme treatment. However, TGF-β receptor inhibitor (TRI, SB525334) inhibited the activation of TGF-β and EMT markers in HK2 cells with Gb3 and lyso-Gb3 treatments. This study suggested that increased plasma lyso-Gb3 has a crucial role in the development of renal fibrosis through the cell-specific induction of the EMT in Fabry disease, and that TRI treatment, alongside enzyme replacement therapy, could be a potential therapeutic option for patients with Fabry disease.

Highlights

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A (α-gal A) [1,2]
The expressions of TGF-β, E-cadherin, N-cadherin, and α-smooth muscle actin (α-SMA) were determined after Gb3 or lyso-Gb3 treatments
Renal fibrosis is a key feature of Fabry doi:10.1371/journal.pone.0136442.g007

Summary

Introduction

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A (α-gal A) [1,2]. The activation of interstitial fibroblasts to cause myofibroblasts that secrete ECM components is associated with renal fibrosis. The EMT is a major mechanism promoting the development of renal interstitial fibrosis. Kidney injury is associated with inflammatory cells, which can give rise to EMT using various growth and differentiation factors, such as TGF-β, receptor tyrosine kinase, Integrin, Wnt, and Notch proteins [12], and under the influence of these, resident fibroblasts and tubular epithelial cells produce basement membrane-degrading enzymes. The induction of the EMT by TGF-β was first recognized in cell culture and has received much attention as a key process that is active during embryonic development, cancer progression, and fibrosis [13]

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Results

Conclusion