Differentially expressed proteins in genetically edited human podocytes: contributing to the understanding of early molecular events in Fabry Disease

Background: Podocyte damage and subsequent proteinuric chronic nephropathy are prominent features of Fabry Disease (FD), a multisystemic X-linked inherited lysosomal storage disorder caused by deficient activity of the alpha-galactosidase A (α-GAL A) enzyme following mutations in the GLA gene. Methods: A proteomic approach based on two-dimensional gel electrophoresis coupled with mass spectrometry was used to explore differentially expressed proteins in podocytes with α-GAL A deficiency. This deficiency was developed through GLA gene deletion using CRISPR/Cas9 genome-editing technology in an immortalized human podocyte culture cell line. To further validate our proteomic findings, we compared the expression of autophagy-specific biomarkers (LC3B and p62) using western blotting, as well as evaluated apoptosis using propidium iodide fluorescence microscopy. Results: Our results showed that protein levels of ubiquitin carboxyl-terminal esterase L1, alpha-enolase, and heat shock protein 60 were reduced FD podocytes. Functional analysis using gene ontology found these proteins were predominately involved in biological processes, including autophagy regulation and apoptosis. Additionally, we found that autophagy-specific biomarkers LC3B and p62 were overexpressed, confirming impaired autophagy regulation and greater apoptosis in FD podocytes. Conclusions Our findings suggest impaired proteostasis in FD podocytes due to concomitant dysfunction of the ubiquitin–proteasome system and the autophagy pathway; both of which are potentially implicated in the pathogenesis of FD nephropathy.