Epigenetics of Aberrant Cardiac Wound Healing

ABSTRACT Remodeling of cardiac tissue architecture is essential for normal organ development and maintaining homeostasis after injury. Injurious insults to the heart, such as hypertension and myocardial infarction, promote cellular responses including stimulation of resident inflammatory cells, activation of endothelial cells and recruitment of immune cells, hypertrophy of cardiomyocytes, and activation of fibroblasts. The physiological goal of this coordinated cellular response is to repair damaged tissue while maintaining or restoring cardiac contractile function. Persistent uncontrolled inflammation, hypertrophy, and fibrosis in the heart due to hyperactive wound healing are detrimental and impair cardiac performance, facilitating the progression to heart failure. Abnormal changes in gene expression promote acquisition of aberrant cellular phenotypes that drive cardiac remodeling. DNA methylation and histone modifications are epigenetic mechanisms that critically regulate chromatin structure and gene expression, and are essential for normal physiology and development. Increasing clinical and experimental evidence suggests that these epigenetic mechanisms are involved in driving aberrant wound healing and the development of heart failure. While most of our knowledge to date is on the heart as a whole, the precise contribution of DNA methylation and histone modifications in regulating aberrant cardiac remodeling at the cellular level is less defined. Therefore, this overview aims to summarize the role of DNA methylation and histone modifications (acetylation and methylation) in heart failure and to comprehensively dissect the role these mechanisms play in regulating the function of cardiomyocytes, fibroblasts, and immune cells in response to injury. © 2018 American Physiological Society. Compr Physiol 8:451‐491, 2018.