Physiologic stress in advanced tissue culture models of cardiomyopathy

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PROJECT SUMMARY/ABSTRACT Multiple forms of muscular dystrophy are characterized by cardiac involvement which can be life-threatening, including Duchenne muscular dystrophy (DMD) and LMNA-related muscular dystrophy. These diseases are caused by mutations in DMD and LMNA, respectively. Heart failure is a leading cause of morbidity and mortality in these diseases. Physiologic mechanical stress in skeletal and cardiac muscle is a main driver of disease in these forms of muscular dystrophy. In addition, cardiac arrhythmias, disproportionate to left ventricular dysfunction, are prominent in LMNA-related disease. New therapeutic strategies, such as exon skipping, gene therapy, and CRISPR-Cas9 gene editing, are in development or have been approved for these diseases. Patient-specific induced pluripotent stem cells can be created and differentiated into cardiomyocytes (iPSC-CMs), offering the opportunity to study patient-specific mutations and test therapeutics in the dish. However, iPSC-CMs are limited by tissue immaturity, non-physiologic stressors, and non-physiologic outputs. Engineered heart tissues are created by seeding iPSC-CMs in a hydrogel matrix that is supported by flexible posts. With these tissue constructs, a more advanced degree of cellular maturation can be achieved, and outputs such as contraction velocity and amplitude can be readily determined. Specific Aim 1 of this K08 award aims assess the effect of physiologic mechanical stress on iPSC-CMs. Specific Aim 2 will improve the assessment of arrhythmogenic potential in novel engineered heart tissue constructs using patient-derived iPSC-CMs harboring DMD and LMNA mutations. Novel therapeutics for both disease entities will be assessed. Preliminary data is presented that demonstrates increased susceptibility of DMD iPSC-CMs to mechanical stress and mitigation of this phenotype by a novel therapeutic. An engineered heart tissue prototype is presented that will allow for the direct electrophysiologic interrogation of these tissues. We expect this prototype, which will allow for more uniform pacing, will be useful, especially in characterizing novel therapeutic effects on LMNA iPSC-CMs. This K08 will support the career development plan for the PI, Dominic Fullenkamp MD PhD, who received his graduate training in biomedical engineering and is physician-scientist cardiologist. Dr. Fullenkamp's long-term objective is to become an independent investigator as a physician scientist at the interface of cardiovascular biology and engineering, and use this interface to test novel therapeutics. In addition to the research proposed, Dr. Fullenkamp aims to use this award to further develop his training in cardiovascular biology under the mentorship of Elizabeth McNally MD PhD and Alfred George MD, two experienced and collaborative mentors, at Northwestern University. His development plan will be supported by internal and external coursework and clinical activity that directly correlates with his research interests.