Keeping a healthy heart beating requires the production of a constant supply of energy, a feat depending on the coordination of several genetic programs. Now, researchers report in the May issue of Cell Metabolism, a publication of Cell Press, that two closely related receptors can act together or separately to pull all of the strings. Drugs that influence these newfound global orchestrators of heart function might offer a novel approach to managing diseases of the heart muscle, according to the researchers.
"The heart is a simple pumping organ," said Vincent Giguere of McGill University in Montreal. "What it needs is energy, which it gets from different fuelsglucose or fatty acidsdepending on their availability. It was thought that separate programs make energy and use it through contraction, but we've revealed two receptors that control the whole setup. That's what's really new."
The orphan nuclear receptor known as ERR was known to scientists as a key regulator in the production of cellular power plants called mitochondria, the researchers explained. But whether ERR or related ERR receptors play a broader role in cardiac energetics and function remained an open question. These receptors are considered "orphans" because the molecules that normally trigger their activity have yet to be defined.
To maintain its essential function, the heart must regulate a cascade of biological processes including the uptake and processing of energy substrates, the conversion of those substrates into usable forms, the sensing of cellular energy charge, and the use of that energy for contraction, the researchers explained.
In their study, the researchers employed a powerful combination of genomic tools to identify the gene promoters to which ERR and bind in the adult mouse heart and to investigate changes in gene and protein expression when levels of ERR are manipulated. That investigation provided evidence that ERR and control most aspect
Contact: Erin Doonan