Mitochondrial stress in GLA mutants Zebrafish is independent of globotriaosylceramide accumulation

Fabry disease (FD) is a hereditary lysosomal storage disorder caused by mutations in GLA gene resulting in reduction or lack of α-galactosidase A activity. In humans, enzymatic deficiency leads to accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in lysosomes. Current therapies focus on reversing Gb3 accumulation but fail to restore altered cellular signaling in the long run. Zebrafish (ZF) lacks Alpha 1,4-Galactosyltransferase (A4GALT) gene and cannot synthesize Gb3 or lysoGb3. We used previously generated GLA-mutant ZF model to investigate Gb3-accumulation-independent alterations by untargeted proteomics analysis of renal tissues. We observed lysosomal and mitochondrial-related pathways disfunction, higher oxidative stress, as indicated by GSH/GSSH and MDA levels, and higher antioxidant activity in mutant ZF. Moreover, mitochondrial morphological alterations also affecting cristae structure were evident. By immunohistochemistry, we also detected decreased lysosomal Tetraspanin (CD63), Superoxide dismutase 2 (SOD2), and Cadherin 1 (CDH1) protein expression. Thus, this ZF model Gb3-independently mirrors GLA mutation-related changes, and unravels novel FD pathogenic mechanisms, thereby representing a powerful tool for innovative drug screening, and the identification of markers of potential clinical relevance.