Abstract Body: Background:
Hypertrophic cardiomyopathy (HCM) is a commonly inherited heart disease characterized by thickened left ventricular walls, leading to contractile dysfunction and potentially fatal arrhythmias. For this reason, an improved understanding of its mechanisms is an important focus for cardiovascular medicine. In particular, the MYBPC3 gene has a definitive disease causation, accounting for 30 to 40% of HCM cases. To investigate this, our study characterized patient lines with MYBPC3 mutations, validating the potential of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) as an in vitro platform for disease modeling and drug testing to advance HCM treatment strategies.

Results:
To study the MYBPC3 mutations, peripheral blood mononuclear cells (PBMCs) were isolated from two HCM patients carrying different MYBPC3 mutations and reprogrammed using Sendai viruses into two iPSC lines: GSBi001-A and GSBi002-A. From these lines, we completed reverse transcription-quantitative polymerase chain reactions (RT-qPCR) to confirm high expression levels of two pluripotency markers: NANOG and SOX2. Immunofluorescence staining showed the protein expression of three pluripotency markers: NANOG, OCT3/4, and SOX2 (Fig. 1). Karyotyping confirmed normal karyotypes. Trilineage differentiation showed differentiation into all three germ layers. Short tandem repeat analysis confirmed the origin of lines from their donors. Sanger sequencing showed the presence of MYBPC3-specific mutations. Mycoplasma detection indicated negative mycoplasma contamination in both lines. Thus, we successfully characterized two iPSC lines from two HCM patients with MYBPC3 mutations.

Conclusion:
Our model shows that patient-specific iPSC lines present a promising platform for modeling MYBPC3-associated HCM in vitro, with further applications in therapeutic development for heart disease. Future studies may seek to assess the pathophysiology of HCM.