title: A universal technology for monitoring G-protein-coupled receptor activation in vitro and noninvasively in live animals.
abstract: G-protein coupled receptors (GPCRs) are a versatile and ubiquitous family of membrane receptors that transmit extracellular signals to mammalian cells and constitute the most important class of drug targets. Yet, sensitive and specific methods are lacking that would allow quantitative comparisons of pharmacologic properties of these receptors in physiological or pathological settings in live animals. We sought to overcome these limitations by employing low affinity, reversible beta-galactosidase complementation to quantify GPCR activation via interaction with beta-arrestin. A panel of cell lines was engineered expressing different GPCRs together with the reporter system. In vitro evaluation revealed highly sensitive, dynamic, and specific assessment of GPCR agonists and antagonists. Following implantation of the cells into mice, it was possible for the first time to monitor pharmacological GPCR activation and inhibition in their physiological context by noninvasive bioluminescence imaging in living animals. This technology has unique advantages that enable novel applications in the functional investigation of GPCR modulation in live animals in biological research and drug discovery.
authors.affiliation: Baxter Laboratory in Genetic Pharmacology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5175, USA.
authors.forename: Georges
authors.initials: G
authors.lastname: von Degenfeld
authors.forename: Tom S
authors.initials: TS
authors.lastname: Wehrman
authors.forename: Mark M
authors.initials: MM
authors.lastname: Hammer
authors.forename: Helen M
authors.initials: HM
authors.lastname: Blau
mesh_terms: D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D049454:Firefly Luciferin; D006801:Humans; D049408:Luminescent Agents; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D049408:Luminescent Agents; D043562:Receptors, G-Protein-Coupled; D049454:Firefly Luciferin