Transgenic Mice Targeting the Heart Unveil G Protein-Coupled Receptor Kinases as Therapeutic Targets

Abstract

GRKs critically regulate βAR signaling via receptor phosphorylation and the triggering of desensitization. In the heart, βARs control the chronotropic, lusitropic, and inotropic responses to the catecholamine neurotransmitters, norepinephrine and epinephrine. Signaling through cardiac βARs is significantly impaired in many cardiovascular disorders, including congestive heart failure.βARK1 (also known as GRK2) is the most abundant GRK in the heart, and it is increased in several cardiovascular diseases associated with impaired cardiac signaling and function, suggesting that this molecule could have pathophysiological relevance in the setting of heart failure. The ability to manipulate the mouse genome has provided a powerful tool to study the physiological implications of altering GRK activity and expression in the heart. Recent studies in several different mouse models have demonstrated that βARK1 plays a key role not only in the regulation of myocardial signaling, but also in cardiac function and development. Moreover, studies have shown that targeting the activity of GRKs, especially βARK1, appears to be a novel therapeutic strategy for the treatment of the failing heart. Gene therapy technology makes it possible, beyond what is possible in the mouse, to directly test in larger animals whether βARK1 inhibition in the setting of disease will improve the function of the compromised heart, and this methodology has also lead to compelling results. These genetic approaches or the development of small molecule inhibitors of βARK1 and GRK activity may advance therapeutic options for heart disease.