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Walsh SK, Lipina C, Ang SY, Sato M, Chia LY, Kocan M, Hutchinson DS, Summers RJ, Wainwright CL. GPR55 regulates the responsiveness to, but does not dimerise with, α 1A-adrenoceptors. Biochem Pharmacol 2021; 188:114560. [PMID: 33844984 DOI: 10.1016/j.bcp.2021.114560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/26/2021] [Accepted: 04/06/2021] [Indexed: 11/15/2022]
Abstract
Emerging evidence suggests that G protein coupled receptor 55 (GPR55) may influence adrenoceptor function/activity in the cardiovascular system. Whether this reflects direct interaction (dimerization) between receptors or signalling crosstalk has not been investigated. This study explored the interaction between GPR55 and the alpha 1A-adrenoceptor (α1A-AR) in the cardiovascular system and the potential to influence function/signalling activities. GPR55 and α1A-AR mediated changes in both cardiac and vascular function was assessed in male wild-type (WT) and GPR55 homozygous knockout (GPR55-/-) mice by pressure volume loop analysis and isolated vessel myography, respectively. Dimerization of GPR55 with the α1A-AR was examined in transfected Chinese hamster ovary-K1 (CHO-K1) cells via Bioluminescence Resonance Energy Transfer (BRET). GPR55 and α1A-AR mediated signalling (extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation) was investigated in neonatal rat ventricular cardiomyocytes using AlphaScreen proximity assays. GPR55-/- mice exhibited both enhanced pressor and inotropic responses to A61603 (α1A-AR agonist), while in isolated vessels, A61603 induced vasoconstriction was attenuated by a GPR55-dependent mechanism. Conversely, GPR55-mediated vasorelaxation was not altered by pharmacological blockade of α1A-ARs with tamsulosin. While cellular studies demonstrated that GPR55 and α1A-AR failed to dimerize, pharmacological blockade of GPR55 altered α1A-AR mediated signalling and reduced ERK1/2 phosphorylation. Taken together, this study provides evidence that GPR55 and α1A-AR do not dimerize to form heteromers, but do interact at the signalling level to modulate the function of α1A-AR in the cardiovascular system.
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Affiliation(s)
- Sarah K Walsh
- Cardiometabolic Health Research, School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Aberdeen AB10 7GJ, UK.
| | - Christopher Lipina
- Division of Cell Signalling and Immunology, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Sheng Y Ang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Martina Kocan
- The Florey Institute of Neuroscience and Mental Health and School of Biosciences, University of Melbourne, Parkville, VIC, Australia
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Cherry L Wainwright
- Cardiometabolic Health Research, School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Aberdeen AB10 7GJ, UK
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