Autophagy modulation enhances enzyme replacement therapy response in Fabry disease

SummaryFabry disease is a lysosomal disease due to -galactosidase A (a-GalA) deficiency. Since 2001, Enzyme replacement therapy (ERT) has been used as specific treatment of Fabry disease, with variable effects depending on patient gender and affected organs. In Fabry cells, the endososomal/lysosomal system is highly altered. Consequently, the exogenous enzyme may be mistargeted and trapped into intracellular vesicles instead of reaching the lysosomes. In this study, we aimed to investigate the mechanisms underlying the processing of the exogenous enzyme. We used Fabry cells (cultured fibroblasts and podocyte cell line) to study the enzyme internalization and its effects on the catabolism of the main a-Gal A substrate, globotriaosylceramide (Gb3), upon autophagy inhibition. The exogenous enzyme reaches the early endosome in a similar timeframe in Fabry and control cells, while its targeting to lysosomes is delayed in Fabry cells. Gb3 concentration is lowered upon therapeutic enzyme addition or wortmannin treatment with a synergetic effect. These findings illustrate the positive impact of autophagy inhibition on enzyme trafficking and processing, allowing the increase of functional enzyme rate within the lysosome. Given the high cost of ERT, a better understanding of the cellular fate of the exogenous enzyme may lead to improve its targeting to the lysosome.