Genome-wide Orchestration of Cardiac Functions by the Orphan Nuclear Receptors ERRα and γ.

Summary: Orphan nuclear receptor ERRα (NR3B1) is recognized as a key regulator of mitochondrial biogenesis, but it is not known whether ERRα and other ERR isoforms play a broader role in cardiac energetics and function. We used genome-wide location analysis and expression profiling to appraise the role of ERRα and γ (NR3B3) in the adult heart. Our data indicate that the two receptors, acting as nonobligatory heterodimers, target a common set of promoters involved in the uptake of energy substrates, production and transport of ATP across the mitochondrial membranes, and intracellular fuel sensing, as well as Ca²⁺ handling and contractile work. Motif-finding algorithms assisted by functional studies indicated that ERR target promoters are enriched for NRF-1, CREB, and STAT3 binding sites. Our study thus reveals that the ERRs orchestrate a comprehensive cardiac transcriptional program and further suggests that modulation of ERR activities could be used to manage cardiomyopathies. [Copyright &y& Elsevier]