PhD student KU Leuven Leuven, Vlaams-Brabant, Belgium
Abstract: Duchenne muscular dystrophy (DMD) affects 1 in 3500 male births, presenting as a severe X-linked genetic disorder caused by mutations within the DMD gene. While advancements in respiratory systems and palliative care have extended patient survival, they have also led to an increase in late-stage lethal complications, notably cardiomyopathy. The absence of dystrophin in DMD cardiomyocytes results in calcium overload, oxidative stress, and mitochondrial dysfunction, with dysregulated NADPH oxidase 4 (NOX4) being identified as a key factor in reactive oxygen species production. However, research into DMD cardiomyopathies has been hindered by limited human samples and preclinical models. Addressing this limitation, we developed long-term cultured 3D cardiac organoids (DMD-COs) from patient-derived induced pluripotent stem cells and CRISPR/Cas9 corrected controls (DMD-Iso-COs). DMD-COs displayed hallmark cardiomyopathic features, such as the presence of fibrotic and adipose tissues, elevated levels of cell death, loss of sarcoglycan, and disruptions in calcium handling, as assessed using the Functional Drug Screening System (FDSS)/μcell system from Hamamatsu Photonics. Bulk RNA sequencing on day 56 revealed enrichment in hypertrophic/dilated cardiomyopathy, arrhythmia, adipogenesis, and fibrosis pathways. To assess their utility for drug screening, we are testing NOX4 inhibitors developed from the enzyme's crystal structure. Preliminary data suggest that NOX4 inhibition may improve the viability and contractility of dystrophic cardiomyocytes, indicating the potential of DMD-COs in drug discovery efforts.
