Cardiac cell modelling of myofibrillar myopathy by AAV-mediated transduction of desmin mutations in human iPSC-derived and neonatal rat cardiomyocytes

Abstract

Myofibrillar myopathy (MFM) is a group of severe cytokeletal proteins known to be caused by mutations in genes encoding. Among the myofibrillar proteins that are accumulated within the muscle fibers of affected patients, they appear to be responsible for the structural integrity of striated muscle. Mutations in the gene lead not only to skeletal muscle myopathies but also to cardiomyopathies, however the cardiac pathological consequences caused by them remain poorly understood. The objective of this work is to examine the effects of MFM-induced mutations in the structural organization of cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) as identified by troponinT immunostaining, and rat neonatal cardiomyocytes. We propose an in vitro cardiac disease-based cellular model based on adeno-associated virus (AAV)-mediated transduction of wild-type (WT) and mutated desmin in fusion with a c-myc tag to distinguish between endogenous and transgenic desmin proteins. Our preliminary results demonstrated that cardiomyocytes were successfully transduced by AAV vectors and expressed exogenous WT desmin as revealed by c-myc immunostaining. For better recapitulating the in vivo anisotropic cardiomyocyte organization, we have developed micro-patterned culture plates made by microcontact printing where thin strips of gelatin have been deposited on top of glass. Culture of both hiPSC-derived and rat neonatal cardiomyocytes on this system improved their sarcomere alignment. The analysis based on immunostaining of protein-markers to examine structural organization in AAV-transduced cardiomyocytes is in progress. Our results indicate that the proposed in vitro model is suitable for the study of the structural defects of desmin-mutated cardiomyocytes.