Abstract 14300: Modeling Human Myofibrillar Desmin-Related Cardiomyopathy With Induced Pluripotent Stem Cells
Chronic conditions such as heart failure and Alzheimer’s are characterized by protein misfolding states for which the underlying mechanism(s) and effective therapies remain poorly defined and elusive goals. Direct reprogramming of somatic cells into iPSC using defined transcription factors provides a robust platform for studies of pathophysiology, enables the development of patient-specific model systems, and opens a gateway for screening disease-specific therapies for personalized medicine. The mutation of the small heat shock protein CryAB causes inheritable multisystem disorders characterized by cataracts, proximal muscle weakness, cardiomyopathy, and sudden cardiac death in humans. We have challenged the existing the paradigm of oxidative stress by demonstrating that mouse hearts exhibiting protein-folding cardiomyopathy found in humans are under ‘reductive stress’. Decreasing the function of G6PD, which generates the NADPH, “cures” the disease in mice by ameliorating reductive stress, aggresome formation, hypertrophy, heart failure, and death. To further understand the molecular mechanisms, we have harvested dermal fibroblasts from WT and Tg R120G CryAB under α-MHC promoter in Tg mice for generation of iPSC. Several clones generated after reprogramming (OCT4, SOX2, KLF4, and C-MYC) are morphologically indistinguishable from mouse ESCs. Like mESCs, these iPSCs have similar karyotypes, express cell surface markers, express pluripotent genes, and also maintain the developmental potential to differentiate into three germ layers. We have begun to characterize iPSCs after differentiation into cardiomyocytes containing protein aggregates. R120G CryAB is over-expressed after cardiomyocyte differentiation of iPSCs by 12 days. In Preliminary studies, we are defining the metabolic profiles of iPSC-induced cardiomyocytes using GC-MS and LC-MS and the effects of such these metabolic perturbations at the post-transcriptional levels using Micro-RNA arrays. In summary, our studies are the first to illustrate whether modeling of a protein-induced myofibrillary disease using iPSC technology is sufficient to recapitulate certain molecular and biochemical properties found either in experimental animal models and/or in humans.
- © 2011 by American Heart Association, Inc.