Deciphering the role of miRNAs in Fabry disease pathology and therapy

• Applicant: Dr. Jeannine Hoepfner
• Subject Area: Cardiology, Angiology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455690513

Fabry disease is a rare and inherited disease caused by mutations in the alpha-galactosidase A (α-Gal A) gene GLA. The lysosomal α-Gal A enzyme catalyzes the hydrolysis of the glycosphingolipid globotriaosylceramide (GL-3). Mutations result in enzyme misfolding and proteasomal degradation leading to accumulation of GL-3 in different organs. Heart failure due to cardiac remodeling with associated left ventricular hypertrophy and myocardial fibrosis is the most prevalent cause for death in Fabry disease. Although GL-3 deposition was found in endothelial cells and cardiomyocytes, the patients’ phenotypes can only partially be attributed to GL-3 deposits. The activation of secondary signaling pathways is being investigated in the development of cell and organ damage. Current treatment strategies, comprising an enzyme replacement and a chaperone therapy, are either only effective for certain mutations or do not show any effects in cardiomyocytes. Hence, there is a tremendous need for investigating the molecular mechanisms underlying the disease phenotype and for developing novel treatment strategies. We previously showed that microRNAs (miRNAs) might play an important role in Fabry disease and identified miRNAs that may have the potential to function as a novel therapeutic approach. The aim of this study is to investigate their functional role in disease development and treatment. We successfully generated induced pluripotent stem cells (iPSCs) and differentiated cardiomyocytes (iPSC-CMs) from Fabry disease patients showing disease-relevant, strongly reduced α-Gal A enzyme activity and lysosomal accumulation of GL-3, thus recapitulating the disease phenotype. In addition, we will generate disease-specific but patient-independent GLA knockdown iPSCs based on CRISPR interference, allowing an inducible, tunable and reversible knockdown of GLA gene expression. Transcriptome and proteome analyses in GLA knockdown iPSC-CMs will reveal dysregulated miRNAs and gene regulatory networks that could be targeted in a novel therapeutic approach. Candidate miRNAs will be investigated for their therapeutic effect in disease- and patient-specific iPSC-CMs. Cellular targets will be identified by bioinformatics approaches, transcriptome and proteome analyses and miRNA-mRNA binding studies. The therapeutic effect of selected miRNAs will be validated in iPSC-CMs comprising different patient sex, GLA gene mutations and disease phenotypes. A proposed miRNA therapy for Fabry disease will be finally applied to human living myocardial slices as an ex vivo multicellular tissue model capable of monitoring functional parameters and, thereby, examining the induction of cardio-toxic side-effects. MiRNAs demonstrating a therapeutic effect in iPSC-CMs and passing cardiotoxicity testing may be further developed for a clinical application in future studies. In summary, we expect that this project will provide insight into the pathology and novel treatment options for Fabry disease.

• DFG Programme: Research Grants