Abstract 14589: Characterization and High-Throughput Drug Screening of a Cardiomyopathy Using Cardiomyocytes From Patient-Derived Induced Pluripotent Stem Cells

Danon disease is an untreatable and severe X-linked form of cardiomyopathy that leads to profound cardiac hypertrophy, causing death or a need for cardiac transplantation in males by the third decade. Danon disease is known to be caused by loss of the lysosome-associated membrane protein-2 (LAMP-2) protein, which is a membrane glycoprotein likely involved in lysosome-autophagosome fusion and vesicle trafficking during autophagy. However, it is unknown how LAMP-2 protein deficiency leads to the development of Danon disease. To better characterize the molecular and cellular pathogenic mechanisms involved and enable high-throughput screening (HTS) of compound libraries, human induced pluripotent stem cells (iPSCs) were generated from patients with Danon disease and differentiated into cardiomyocytes. RNA transcription levels from the Danon iPSC-derived cardiomyocytes (iPSC-CMs) were analyzed using RNA-Sequencing (RNA-Seq) and expression of key genes confirmed via quantitative real-time PCR (qRT-PCR). The data show significant upregulation of genes involved in cellular respiration and sarcomere expression in Danon iPSC-CMs compared to unaffected control iPSC-CMs. The upregulation of cellular respiration transcripts in our data align with published data suggesting mitochondrial function is affected in these cells, including increased levels of mitochondrial oxidative stress. Our RNA-Seq findings of potentially impacted molecular pathways in the Danon iPSC-CM model have been used to identify biomarkers, such as the sarcomeric protein troponin T type 2, for conducting HTS drug discovery. Following development and validation of a primary HTS assay, a pilot HTS using a library of 355 kinase inhibitors and then a HTS drug discovery using a custom designed diversity library of 20,000 compounds will be performed and hits confirmed using secondary and tertiary assays. These confirmed hits may offer novel potential therapeutic treatments for individuals with this currently devastating and untreatable cardiomyopathy.