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Mouat MA, Wilkins BP, Ding E, Govindaraju H, Coleman JLJ, Graham RM, Turner N, Smith NJ. Metabolic Profiling of Mice with Deletion of the Orphan G Protein-Coupled Receptor, GPR37L1. Cells 2022; 11:cells11111814. [PMID: 35681509 PMCID: PMC9180194 DOI: 10.3390/cells11111814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/18/2022] [Accepted: 05/30/2022] [Indexed: 02/01/2023] Open
Abstract
Understanding the neurogenic causes of obesity may reveal novel drug targets to counter the obesity crisis and associated sequelae. Here, we investigate whether the deletion of GPR37L1, an astrocyte-specific orphan G protein-coupled receptor, affects whole-body energy homeostasis in mice. We subjected male Gpr37l1−/− mice and littermate wildtype (Gpr37l1+/+, C57BL/6J background) controls to either 12 weeks of high-fat diet (HFD) or chow feeding, or to 1 year of chow diet, with body composition quantified by EchoMRI, glucose handling by glucose tolerance test and metabolic rate by indirect calorimetry. Following an HFD, Gpr37l1−/− mice had similar glucose handling, body weight and fat mass compared with wildtype controls. Interestingly, we observed a significantly elevated respiratory exchange ratio in HFD- and chow-fed Gpr37l1−/− mice during daylight hours. After 1 year of chow feeding, we again saw no differences in glucose and insulin tolerance or body weight between genotypes, nor in energy expenditure or respiratory exchange ratio. However, there was significantly lower fat mass accumulation, and higher ambulatory activity in the Gpr37l1−/− mice during night hours. Overall, these results indicate that while GPR37L1 may play a minor role in whole-body metabolism, it is not a viable clinical target for the treatment of obesity.
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Affiliation(s)
- Margaret A. Mouat
- Orphan Receptor Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (M.A.M.); (B.P.W.)
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (J.L.J.C.); (R.M.G.)
| | - Brendan P. Wilkins
- Orphan Receptor Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (M.A.M.); (B.P.W.)
| | - Eileen Ding
- Mitochondrial Bioenergetics Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (E.D.); (H.G.)
| | - Hemna Govindaraju
- Mitochondrial Bioenergetics Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (E.D.); (H.G.)
| | - James L. J. Coleman
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (J.L.J.C.); (R.M.G.)
| | - Robert M. Graham
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (J.L.J.C.); (R.M.G.)
| | - Nigel Turner
- Mitochondrial Bioenergetics Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (E.D.); (H.G.)
- Cellular Bioenergetics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
- Correspondence: (N.T.); (N.J.S.)
| | - Nicola J. Smith
- Orphan Receptor Laboratory, School of Medical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW 2052, Australia; (M.A.M.); (B.P.W.)
- Correspondence: (N.T.); (N.J.S.)
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Mouat MA, Coleman JLJ, Wu J, Dos Remedios CG, Feneley MP, Graham RM, Smith NJ. Involvement of GPR37L1 in murine blood pressure regulation and human cardiac disease pathophysiology. Am J Physiol Heart Circ Physiol 2021; 321:H807-H817. [PMID: 34533400 DOI: 10.1152/ajpheart.00198.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/14/2021] [Indexed: 01/23/2023]
Abstract
Multiple mouse lines lacking the orphan G protein-coupled receptor, GPR37L1, have elicited disparate cardiovascular phenotypes. The first Gpr37l1 knockout mice study to be published reported a marked elevation in systolic blood pressure (SBP; ∼60 mmHg), revealing a potential therapeutic opportunity. The phenotype differed from our own independently generated knockout line, where male mice exhibited equivalent baseline blood pressure to wild type. Here, we attempted to reproduce the first study by characterizing the cardiovascular phenotype of both the original knockout and transgenic lines alongside a C57BL/6J control line, using the same method of blood pressure measurement. The present study supports the findings from our independently developed Gpr37l1 knockout line, finding that SBP and diastolic blood pressure (DBP) are not different in the original Gpr37l1 knockout male mice (SBP: 130.9 ± 5.3 mmHg; DBP: 90.7 ± 3.0 mmHg) compared with C57BL/6J mice (SBP: 123.1 ± 4.1 mmHg; DBP: 87.0 ± 2.7 mmHg). Instead, we attribute the apparent hypertension of the knockout line originally described to comparison with a seemingly hypotensive transgenic line (SBP 103.7 ± 5.0 mmHg; DBP 71.9 ± 3.7 mmHg). Additionally, we quantified myocardial GPR37L1 transcript in humans, which was suggested to be downregulated in cardiovascular disease. We found that GPR37L1 has very low native transcript levels in human myocardium and that expression is not different in tissue samples from patients with heart failure compared with sex-matched healthy control tissue. These findings indicate that cardiac GPR37L1 expression is unlikely to contribute to the pathophysiology of human heart failure.NEW & NOTEWORTHY This study characterizes systolic blood pressure (SBP) in a Gpr37l1 knockout mouse line, which was previously reported to have ∼60 mmHg higher SBP compared with a transgenic line. We observed only a ∼27 mmHg SBP difference between the lines. However, when compared with C57BL/6J mice, knockout mice showed no difference in SBP. We also investigated GPR37L1 mRNA abundance in human hearts and observed no difference between healthy and failing heart samples.
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Affiliation(s)
- Margaret A Mouat
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - James L J Coleman
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Jianxin Wu
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- Cardiac Physiology and Transplantation Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Cristobal G Dos Remedios
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Michael P Feneley
- Cardiac Physiology and Transplantation Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Robert M Graham
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Nicola J Smith
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
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Ngo T, Ilatovskiy AV, Stewart AG, Coleman JLJ, McRobb FM, Riek RP, Graham RM, Abagyan R, Kufareva I, Smith NJ. Retraction Note: Orphan receptor ligand discovery by pickpocketing pharmacological neighbors. Nat Chem Biol 2021; 17:501. [PMID: 33649604 PMCID: PMC7990710 DOI: 10.1038/s41589-021-00746-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tony Ngo
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Andrey V Ilatovskiy
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Alastair G Stewart
- St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia.,Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - James L J Coleman
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Fiona M McRobb
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - R Peter Riek
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Robert M Graham
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Ruben Abagyan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA.
| | - Nicola J Smith
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia. .,St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia.
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Ngo T, Wilkins BP, So SS, Keov P, Chahal KK, Finch AM, Coleman JLJ, Kufareva I, Smith NJ. Orphan receptor GPR37L1 remains unliganded. Nat Chem Biol 2021; 17:383-386. [PMID: 33649602 DOI: 10.1038/s41589-021-00748-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/25/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Brendan P Wilkins
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.,Orphan Receptor Pharmacology Laboratory, School of Medical Sciences, UNSW Sydney, Kensington, New South Wales, Australia
| | - Sean S So
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.,Orphan Receptor Pharmacology Laboratory, School of Medical Sciences, UNSW Sydney, Kensington, New South Wales, Australia
| | - Peter Keov
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Kirti K Chahal
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Angela M Finch
- G Protein-Coupled Receptor Laboratory, School of Medical Sciences, UNSW Sydney, Kensington, New South Wales, Australia
| | - James L J Coleman
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Nicola J Smith
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia. .,Orphan Receptor Pharmacology Laboratory, School of Medical Sciences, UNSW Sydney, Kensington, New South Wales, Australia.
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Mouat MA, Jackson KL, Coleman JLJ, Paterson MR, Graham RM, Head GA, Smith NJ. Deletion of Orphan G Protein-Coupled Receptor GPR37L1 in Mice Alters Cardiovascular Homeostasis in a Sex-Specific Manner. Front Pharmacol 2021; 11:600266. [PMID: 33633567 PMCID: PMC7901490 DOI: 10.3389/fphar.2020.600266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
GPR37L1 is a family A orphan G protein-coupled receptor (GPCR) with a putative role in blood pressure regulation and cardioprotection. In mice, genetic ablation of Gpr37l1 causes sex-dependent effects; female mice lacking Gpr37l1 (GPR37L1-/-) have a modest but significant elevation in blood pressure, while male GPR37L1-/- mice are more susceptible to cardiovascular dysfunction following angiotensin II-induced hypertension. Given that this receptor is highly expressed in the brain, we hypothesize that the cardiovascular phenotype of GPR37L1-/- mice is due to changes in autonomic regulation of blood pressure and heart rate. To investigate this, radiotelemetry was employed to characterize baseline cardiovascular variables in GPR37L1-/- mice of both sexes compared to wildtype controls, followed by power spectral analysis to quantify short-term fluctuations in blood pressure and heart rate attributable to alterations in autonomic homeostatic mechanisms. Additionally, pharmacological ganglionic blockade was performed to determine vasomotor tone, and environmental stress tests were used to assess whether cardiovascular reactivity was altered in GPR37L1-/- mice. We observed that mean arterial pressure was significantly lower in female GPR37L1-/- mice compared to wildtype counterparts, but was unchanged in male GPR37L1-/- mice. GPR37L1-/- genotype had a statistically significant positive chronotropic effect on heart rate across both sexes when analyzed by two-way ANOVA. Power spectral analysis of these data revealed a reduction in power in the heart rate spectrum between 0.5 and 3 Hz in female GPR37L1-/- mice during the diurnal active period, which indicates that GPR37L1-/- mice may have impaired cardiac vagal drive. GPR37L1-/- mice of both sexes also exhibited attenuated depressor responses to ganglionic blockade with pentolinium, indicating that GPR37L1 is involved in maintaining sympathetic vasomotor tone. Interestingly, when these mice were subjected to aversive and appetitive behavioral stressors, the female GPR37L1-/- mice exhibited an attenuation of cardiovascular reactivity to aversive, but not appetitive, environmental stimuli. Together, these results suggest that loss of GPR37L1 affects autonomic maintenance of blood pressure, giving rise to sex-specific cardiovascular changes in GPR37L1-/- mice.
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Affiliation(s)
- Margaret A Mouat
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - James L J Coleman
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Madeleine R Paterson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Robert M Graham
- St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Nicola J Smith
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
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Coleman JLJ, Ngo T, Smith NJ. Corrigendum to "The G protein-coupled receptor N-terminus and receptor signalling: N-tering a new era" [Cellular Signalling 2017 May;33:1-9]. Cell Signal 2020; 68:109510. [PMID: 31928906 DOI: 10.1016/j.cellsig.2019.109510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- J L J Coleman
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
| | - T Ngo
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - N J Smith
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Affiliation(s)
- James L. J. Coleman
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
- St Vincent’s Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Tony Ngo
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
- St Vincent’s Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Johannes Schmidt
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Nadine Mrad
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Chu Kong Liew
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Nicole M. Jones
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Kensington, New South Wales 2033, Australia
| | - Robert M. Graham
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
- St Vincent’s Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Nicola J. Smith
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
- St Vincent’s Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
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Mouat MA, Coleman JLJ, Smith NJ. GPCRs in context: sexual dimorphism in the cardiovascular system. Br J Pharmacol 2018; 175:4047-4059. [PMID: 29451687 DOI: 10.1111/bph.14160] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/31/2018] [Accepted: 02/09/2018] [Indexed: 12/31/2022] Open
Abstract
Cardiovascular disease (CVD) remains the largest cause of mortality worldwide, and there is a clear gender gap in disease occurrence, with men being predisposed to earlier onset of CVD, including atherosclerosis and hypertension, relative to women. Oestrogen may be a driving factor for female-specific cardioprotection, though androgens and sex chromosomes are also likely to contribute to sexual dimorphism in the cardiovascular system (CVS). Many GPCR-mediated processes are involved in cardiovascular homeostasis, and some exhibit clear sex divergence. Here, we focus on the G protein-coupled oestrogen receptor, endothelin receptors ETA and ETB and the eicosanoid G protein-coupled receptors (GPCRs), discussing the evidence and potential mechanisms leading to gender dimorphic responses in the vasculature. The use of animal models and pharmacological tools has been essential to understanding the role of these receptors in the CVS and will be key to further delineating their sex-specific effects. Ultimately, this may illuminate wider sex differences in cardiovascular pathology and physiology. LINKED ARTICLES This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
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Affiliation(s)
- Margaret A Mouat
- Molecular Pharmacology Laboratory, Division of Molecular Cardiology and Biophysics, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, NSW, Australia
| | - James L J Coleman
- Molecular Pharmacology Laboratory, Division of Molecular Cardiology and Biophysics, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, NSW, Australia
| | - Nicola J Smith
- Molecular Pharmacology Laboratory, Division of Molecular Cardiology and Biophysics, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, NSW, Australia
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Coleman JLJ, Ngo T, Smith NJ. The G protein-coupled receptor N-terminus and receptor signalling: N-tering a new era. Cell Signal 2017; 33:1-9. [PMID: 28188824 DOI: 10.1016/j.cellsig.2017.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 02/06/2017] [Indexed: 01/22/2023]
Abstract
G protein-coupled receptors (GPCRs) are a vast family of membrane-traversing proteins, essential to the ability of eukaryotic life to detect, and mount an intracellular response to, a diverse range of extracellular stimuli. GPCRs have evolved with archetypal features including an extracellular N-terminus and intracellular C-terminus that flank a transmembrane structure of seven sequential helices joined by intracellular and extracellular loops. These structural domains contribute to the ability of a GPCR to be correctly synthesised and inserted into the cell membrane, to interact with its cognate ligand(s) and to couple with signal-transducing heterotrimeric G proteins, allowing the activated receptor to selectively modulate a number of signalling cascades. Whilst well known for its importance in receptor translation and trafficking, the GPCR N-terminus is underexplored as a participant in receptor signalling. This review aims to discuss and integrate recent advances in knowledge of the vital roles of the GPCR N-terminus in receptor signalling.
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Affiliation(s)
- James L J Coleman
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
| | - Tony Ngo
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Nicola J Smith
- Molecular Pharmacology Group, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Coleman JLJ, Ngo T, Schmidt J, Mrad N, Liew CK, Jones NM, Graham RM, Smith NJ. Metalloprotease cleavage of the N terminus of the orphan G protein-coupled receptor GPR37L1 reduces its constitutive activity. Sci Signal 2016; 9:ra36. [PMID: 27072655 DOI: 10.1126/scisignal.aad1089] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Little is known about the pharmacology or physiology of GPR37L1, a G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor that is abundant in the cerebellum. Mice deficient in this receptor exhibit precocious cerebellar development and hypertension. We showed that GPR37L1 coupled to the G protein Gα(s) when heterologously expressed in cultured cells in the absence of any added ligand, whereas a mutant receptor that lacked the amino terminus was inactive. Conversely, inhibition of ADAMs (a disintegrin and metalloproteases) enhanced receptor activity, indicating that the presence of the amino terminus is necessary for GPR37L1 signaling. Metalloprotease-dependent processing of GPR37L1 was evident in rodent cerebellum, where we detected predominantly the cleaved, inactive form. However, comparison of the accumulation of cAMP (adenosine 3',5'-monophosphate) in response to phosphodiesterase inhibition in cerebellar slice preparations from wild-type and GPR37L1-null mice showed that some constitutive signaling remained in the wild-type mice. In reporter assays of Gα(s) or Gα(i) signaling, the synthetic, prosaposin-derived peptide prosaptide (TX14A) did not increase GPR37L1 activity. Our data indicate that GPR37L1 may be a constitutively active receptor, or perhaps its ligand is present under the conditions that we used for analysis, and that the activity of this receptor is instead controlled by signals that regulate metalloprotease activity in the tissue.
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Affiliation(s)
- James L J Coleman
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia. St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Tony Ngo
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia. St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Johannes Schmidt
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Nadine Mrad
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Chu Kong Liew
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Nicole M Jones
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Kensington, New South Wales 2033, Australia
| | - Robert M Graham
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia. St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Nicola J Smith
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia. St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia.
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Coleman JLJ, Brennan K, Ngo T, Balaji P, Graham RM, Smith NJ. Rapid Knockout and Reporter Mouse Line Generation and Breeding Colony Establishment Using EUCOMM Conditional-Ready Embryonic Stem Cells: A Case Study. Front Endocrinol (Lausanne) 2015; 6:105. [PMID: 26175717 PMCID: PMC4485191 DOI: 10.3389/fendo.2015.00105] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 06/15/2015] [Indexed: 12/18/2022] Open
Abstract
As little as a decade ago, generation of a single knockout mouse line was an expensive and time-consuming undertaking available to relatively few researchers. The International Knockout Mouse Consortium, established in 2007, has revolutionized the use of such models by creating an open-access repository of embryonic stem (ES) cells that, through sequential breeding with first FLP1 recombinase and then Cre recombinase transgenic mice, facilitates germline global or conditional deletion of almost every gene in the mouse genome. In this Case Study, we describe our experience using the repository to create mouse lines for a variety of experimental purposes. Specifically, we discuss the process of obtaining germline transmission of two European Conditional Mouse Mutagenesis Program (EUCOMM) "knockout-first" gene targeted constructs and the advantages and pitfalls of using this system. We then outline our breeding strategy and the outcomes of our efforts to generate global and conditional knockouts and reporter mice for the genes of interest. Line maintenance, removal of recombinase transgenes, and cryopreservation are also considered. Our approach led to the generation of heterozygous knockout mice within 6 months of commencing breeding to the founder mice. By describing our experiences with the EUCOMM ES cells and subsequent breeding steps, we hope to assist other researchers with the application of this valuable approach to generating versatile knockout mouse lines.
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Affiliation(s)
- James L. J. Coleman
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St. Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Karen Brennan
- BioCORE, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Tony Ngo
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St. Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Poornima Balaji
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St. Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Robert M. Graham
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St. Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
- *Correspondence: Nicola J. Smith and Robert M. Graham, Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool Street, Darlinghurst, NSW 2010, Australia, ;
| | - Nicola J. Smith
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St. Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
- *Correspondence: Nicola J. Smith and Robert M. Graham, Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool Street, Darlinghurst, NSW 2010, Australia, ;
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