A Critical Role for Estrogen-Related Receptor Signaling in Cardiac Maturation

Abstract

Rationale: The heart undergoes dramatic developmental changes during the prenatal to postnatal transition, including maturation of cardiac myocyte energy metabolic and contractile machinery. Delineation of the mechanisms involved in cardiac postnatal development could provide new insight into the fetal shifts that occur in the diseased heart and unveil strategies for driving maturation of stem cell-derived cardiac myocytes. Objective: To delineate transcriptional drivers of cardiac maturation. Methods and Results: We hypothesized that ERR (estrogen-related receptor) alpha and gamma, known transcriptional regulators of postnatal mitochondrial biogenesis and function, serve a role in the broader cardiac maturation program. We devised a strategy to knockdown the expression of ERR alpha and gamma in heart after birth (pn-csERR alpha/gamma [postnatal cardiac-specific ERR alpha/gamma]) in mice. With high levels of knockdown, pn-csERR alpha/gamma knockdown mice exhibited cardiomyopathy with an arrest in mitochondrial maturation. RNA sequence analysis of pn-csERR alpha/gamma knockdown hearts at 5 weeks of age combined with chromatin immunoprecipitation with deep sequencing and functional characterization conducted in human induced pluripotent stem cell-derived cardiac myocytes (hiPSC-CM) demonstrated that ERR gamma activates transcription of genes involved in virtually all aspects of postnatal developmental maturation, including mitochondrial energy transduction, contractile function, and ion transport. In addition, ERR gamma was found to suppress genes involved in fibroblast activation in hearts of pn-csERR alpha/gamma knockdown mice. Disruption ofEsrraandEsrrgin mice during fetal development resulted in perinatal lethality associated with structural and genomic evidence of an arrest in cardiac maturation, including persistent expression of early developmental and noncardiac lineage gene markers including cardiac fibroblast signatures. Lastly, targeted deletion ofESRRAandESRRGin hiPSC-CM derepressed expression of early (transcription factor 21 or TCF21) and mature (periostin, collagen type III) fibroblast gene signatures. Conclusions: ERR alpha and gamma are critical regulators of cardiac myocyte maturation, serving as transcriptional activators of adult cardiac metabolic and structural genes, an.d suppressors of noncardiac lineages including fibroblast determination.