beta-Arrestin1 mediates nicotinic acid-induced flushing, but not its antilipolytic effect, in mice.
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Nicotinic acid is one of the most effective agents for both lowering triglycerides and raising HDL. However, the side effect of cutaneous flushing severely limits patient compliance. As nicotinic acid stimulates the GPCR GPR109A and Gi/Go proteins, here we dissected the roles of G proteins and the adaptor proteins, beta-arrestins, in nicotinic acid-induced signaling and physiological responses. In a human cell line-based signaling assay, nicotinic acid stimulation led to pertussis toxin-sensitive lowering of cAMP, recruitment of beta-arrestins to the cell membrane, an activating conformational change in beta-arrestin, and beta-arrestin-dependent signaling to ERK MAPK. In addition, we found that nicotinic acid promoted the binding of beta-arrestin1 to activated cytosolic phospholipase A2 as well as beta-arrestin1-dependent activation of cytosolic phospholipase A2 and release of arachidonate, the precursor of prostaglandin D2 and the vasodilator responsible for the flushing response. Moreover, beta-arrestin1-null mice displayed reduced cutaneous flushing in response to nicotinic acid, although the improvement in serum free fatty acid levels was similar to that observed in wild-type mice. These data suggest that the adverse side effect of cutaneous flushing is mediated by beta-arrestin1, but lowering of serum free fatty acid levels is not. Furthermore, G protein-biased ligands that activate GPR109A in a beta-arrestin-independent fashion may represent an improved therapeutic option for the treatment of dyslipidemia.
Extracellular Signal-Regulated MAP Kinases
Fatty Acids, Nonesterified
Mice, Inbred C57BL
Phospholipases A2, Cytosolic
Regional Blood Flow
Published Version (Please cite this version)10.1172/JCI36806
Publication InfoChen, JR; DeWire, SM; Kovacs, JJ; Lam, CM; Lefkowitz, Robert J; Muehlbauer, Michael J; ... Whalen, EJ (2009). beta-Arrestin1 mediates nicotinic acid-induced flushing, but not its antilipolytic effect, in mice. J Clin Invest, 119(5). pp. 1312-1321. 10.1172/JCI36806. Retrieved from http://hdl.handle.net/10161/5928.
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James B. Duke Professor of Medicine
The focus of work in this laboratory is on the elucidation of the molecular properties and regulatory mechanisms controlling the function of G protein-coupled receptors. As model systems we utilize the so called adrenergic receptors for adrenaline and related molecules. The goal is to learn the general principles of signal transduction from the outside to the inside of the cell which are involved in systems as diverse as sensory perception, neuro- transmitter and hormonal signaling. Stud