Elucidation of pathogenic mechanisms for Fabry disease by transcriptome analysis (690.10)

Abstract

Fabry disease is an X‐linked inborn error of glycosphingolipid metabolism associated with deficient alpha‐galactosidase A activity. The major clinical feature of Fabry disease, such as fibrosis in cardiomyopathy and renal failure has been observed with abnormal accumulation of globotriaosylceramide (Gb3) in biological fluids, vascular endothelium, heart and kidney. In addition to Gb3, increased concentration of deacylated Gb3 (lyso‐Gb3) in the plasma of symptomatic patients also has been suggested as a causative molecular event. However, the correlation between fibrogenesis and elevated levels of these sphingolipids is poorly understood. To elucidate the genetic mechanisms involved in renal fibrosis in fabry disease, we analyzed the changes of global gene expression before and after Gb3 or lyso‐Gb3 treatment on two types of kidney cell lines, human proximal renal tubular epithelial cells (HK‐2) and mouse renal glomerular mesangial cells (SV40MES13), using microarray. The results showed that Gb3 and lyso‐Gb3 regulate the expression of 199 and 328 genes in each cell type, with at least 2.0‐fold change considerations. To identify key biological functions, we classified all the genes into 4 groups based on the expression patterns (1) Gb3 up, (2) Gb3 down, (3)lyso‐Gb3 up, (4)lyso‐Gb3 down regulated genes and performed functional annotation analysis using the DAVID tool. Most biological functions were related to fibrogenesis or epithelial‐mesenchymal transition (EMT). Interestingly, the gene expression patterns were significantly different between treated with Gb3 and treated with lyso‐Gb3. The expressions of EMT related genes (F8, FOXP2, HOXA11, DLL1 and WT1) were confirmed by realtime‐PCR or Western blot. These findings suggested that Gb3 and lyso‐Gb3 lead to renal fibrosis in Fabry disease with different biochemical modulations.