A fundamental, but unsolved problem in heart diseases is irreversible loss of cardiomyocytes that is replaced by fibrotic scar in response to injury. Therefore, to convert cardiac fibroblasts, the most abundant cell type in the heart, into cardiomyocytes after injury is a particularly attractive heart repair strategy. Over the last several years, we have made several important contributions toward this goal: 1) in vitro reprogramming of adult mouse fibroblasts into beating cardiomyocytes by forced expression of four cardiogenic transcription factors (Nature 2012; 485: 599-604), 2) developing in vivo reprogramming strategy targeting activated cardiac fibroblasts after myocardial infarction which improved heart function and reduced scar formation infarction (Nature 2012; 485: 599-604, Nature Medicine 2013;19: 413-415), 3) identifying the optimal combination of factors that is necessary and sufficient to induce a contractile phenotype in adult human fibroblasts (PNAS 2013;110(14):5588-5593), and 4) defining the cardiomyocyte subtype-specific properties of reprogrammed cells (Development 2014;141(22):4267-78). Based on these progresses, the new research direction in my lab is to understand cardiac fate specification during de novo cardiomyocyte generation and thus to develop entirely new cardiomyocyte induction strategies targeting individual subtypes of cardiomyocytes including atrial, ventricular, and pacemaker cardiomyocytes by direct reprogramming of fibroblasts and directed cardiac differentiation of pluripotent stem cells.
Young-Jae received his M.D. at Seoul National University of College of Medicine in South Korea. He completed his Ph.D work at Albert Einstein College of Medicine under the supervision of Dr. Rick Kitsis. Following Internal Medicine Residency training, he entered Physician-Scientist Training pathway in Cardiovascular Medicine at UT Southwestern Medical Center. After clinical cardiology training, he joined Dr. Eric Olson’s lab where he studied cardiac reprogramming. He is a faculty member in the Division of Cardiovascular Medicine and Department of Cell and Developmental Biology and Vanderbilt Center for Stem Cell Biology at Vanderbilt.