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Richards BK, Ch'ng SS, Simon AB, Pang TY, Kim JH, Lawrence AJ, Perry CJ. Relaxin family peptide receptor 3 (RXFP3) expressing cells in the zona incerta/lateral hypothalamus augment behavioural arousal. J Neurochem 2024. [PMID: 39233365 DOI: 10.1111/jnc.16217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 08/15/2024] [Accepted: 08/17/2024] [Indexed: 09/06/2024]
Abstract
Fear-related psychopathologies, such as post-traumatic stress disorder, are linked to dysfunction in neural circuits that govern fear memory and arousal. The lateral hypothalamus (LH) and zona incerta (ZI) regulate fear, but our understanding of the precise neural circuits and cell types involved remains limited. Here, we examined the role of relaxin family peptide receptor 3 (RXFP3) expressing cells in the LH/ZI in conditioned fear expression and general arousal in male RXFP3-Cre mice. We found that LH/ZI RXFP3+ (LH/ZIRXFP3) cells projected strongly to fear learning, stress, and arousal centres, notably, the periaqueductal grey, lateral habenula, and nucleus reuniens. These cells do not express hypocretin/orexin or melanin-concentrating hormone but display putative efferent connectivity with LH hypocretin/orexin+ neurons and dopaminergic A13 cells. Following Pavlovian fear conditioning, chemogenetically activating LH/ZIRXFP3 cells reduced fear expression (freezing) overall but also induced jumping behaviour and increased locomotor activity. Therefore, the decreased freezing was more likely to reflect enhanced arousal rather than reduced fear. Indeed, stimulating these cells produced distinct patterns of coactivation between several motor, stress, and arousal regions, as measured by Fos expression. These results suggest that activating LH/ZIRXFP3 cells generates brain-wide activation patterns that augment behavioural arousal.
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Affiliation(s)
- Brandon K Richards
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
- School of Psychological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Sarah S Ch'ng
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Ariel B Simon
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Terence Y Pang
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
- Institute of Health and Sports (IHES), Victoria University, Footscray, Victoria, Australia
| | - Jee Hyun Kim
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
- IMPACT-The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Christina J Perry
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
- School of Psychological Sciences, Macquarie University, North Ryde, New South Wales, Australia
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2
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Anversa RG, Barron ML, Walker LC, Lawrence AJ. Emerging GPCR targets for AUD: Insights from preclinical studies. Curr Opin Neurobiol 2024; 87:102896. [PMID: 38971113 DOI: 10.1016/j.conb.2024.102896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 07/08/2024]
Abstract
G protein-coupled receptors (GPCRs) are the largest group of membrane receptors in the central nervous system and one of the key proteins for signal transduction between cells. Currently, many drugs available on the market act via GPCRs and these receptors remain attractive targets for the treatment of brain disorders, including alcohol use disorder (AUD). Here, we describe the most recent literature, with a primary focus on the past 5 years, on GPCR targets with the potential for reducing behaviours associated with excessive alcohol intake. Specifically, we focus on preclinical evidence of compounds with attractive pharmacological profiles and potential for future clinical investigation for the treatment of AUD.
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Affiliation(s)
- Roberta Goncalves Anversa
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne 3052, Australia
| | - Maiya L Barron
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Leigh C Walker
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne 3052, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne 3052, Australia.
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Eraslan IM, Egberts-Brugman M, Read JL, Voglsanger LM, Samarasinghe RM, Hamilton L, Dhar P, Williams RJ, Walker LC, Ch'ng S, Lawrence AJ, Walker AJ, Dean OM, Gundlach AL, Smith CM. Neuroanatomical distribution of fluorophores within adult RXFP3 Cre-tdTomato/YFP mouse brain. Biochem Pharmacol 2024; 225:116265. [PMID: 38714277 DOI: 10.1016/j.bcp.2024.116265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 05/01/2024] [Accepted: 05/03/2024] [Indexed: 05/09/2024]
Abstract
Relaxin-family peptide 3 receptor (RXFP3) is activated by relaxin-3 in the brain to influence arousal and related functions, such as feeding and stress responses. Two transgenic mouse lines have recently been developed that co-express different fluorophores within RXFP3-expressing neurons: either yellow fluorescent protein (YFP; RXFP3-Cre/YFP mice) or tdTomato (RXFP3-Cre/tdTomato mice). To date, the characteristics of neurons that express RXFP3-associated fluorophores in these mice have only been investigated in the bed nucleus of the stria terminalis and the hypothalamic arcuate nucleus. To better determine the utility of these fluorophore-expressing mice for further research, we characterised the neuroanatomical distribution of fluorophores throughout the brain of these mice and compared this to the published distribution of Rxfp3 mRNA (detected by in situ hybridisation) in wildtype mice. Coronal sections of RXFP3-Cre/YFP (n = 8) and RXFP3-Cre/tdTomato (n = 8) mouse brains were imaged, and the density of fluorophore-expressing cells within various brain regions/nuclei was qualitatively assessed. Comparisons with our previously reported RXFP3 mRNA distribution revealed that of 212 brain regions that contained either fluorophore or RXFP3 mRNA, approximately half recorded densities that were within two qualitative measurements of each other (on a 9-point scale), including hippocampal dentate gyrus and amygdala subregions. However, many brain areas with likely non-authentic, false-positive, or false-negative fluorophore expression were also detected, including the cerebellum. Therefore, this study provides a guide to which brain regions should be prioritized for future study of RXFP3 in these mice, to better understand the neuroanatomy and function of this intriguing, neuronal peptide receptor.
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Affiliation(s)
- Izel M Eraslan
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Monique Egberts-Brugman
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Justin L Read
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Lara M Voglsanger
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Rasika M Samarasinghe
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Lee Hamilton
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Poshmaal Dhar
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Richard J Williams
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Leigh C Walker
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Sarah Ch'ng
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Adam J Walker
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Olivia M Dean
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Craig M Smith
- Faculty of Health, School of Medicine, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria 3216, Australia.
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4
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Zhang C, Sun Y, Kang L, Jiang Y. Characterization of chicken Relaxin3 gene: mRNA expression and response to reproductive hormone treatment in ovarian granulosa cells, and single nucleotide polymorphisms associated with egg laying traits in hens. Anim Biotechnol 2024:2370810. [PMID: 38940516 DOI: 10.1080/10495398.2024.2370810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
As a protein structurally similar to insulin, relaxin3 (RLN3) plays a role in promoting arousal, suppressing depressive or anxious behaviors. Two studies revealed the increase of RLN3 expression during chicken follicle selection. In this study, by real-time quantitative PCR and luciferase assay, mRNA expression and single nucleotide polymorphisms (SNPs) of chicken RLN3 were investigated. The mRNA expression of chicken RLN3 was higher in the granulosa cell of hierarchal follicles (Post-GCs) than that of pre-hierarchal follicles (Pre-GCs). In Pre-GCs, the mRNA expression of chicken RLN3 was stimulated by FSH and progesterone; in Post-GCs, it was stimulated by higher concentration of estrogen and FSH, however, was inhibited by progesterone. Four SNPs including g.-655G > C, g-592G > A, g.-372T > A and g.-282G > C were identified in the critical promoter region from -1291 bp to -207 bp of chicken RLN3, among which g.-655G > C, and g-592G > A were associated with age at first laying and clutch size, respectively, in Zaozhuang Sunzhi chickens. At g.-655G > C and g-592G > A, allele C and allele A had higher transcriptional activity, respectively. These data suggest that RLN3 plays an important role in chicken follicle development and SNPs in its promoter region are potential DNA markers for improving egg production traits.
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Affiliation(s)
- Chunfeng Zhang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Yi Sun
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Li Kang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Yunliang Jiang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
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Rahman MT, Chaminda Lakmal HH, Hussain J, Jin C. Targeting the relaxin-3/RXFP3 system: a patent review for the last two decades. Expert Opin Ther Pat 2024; 34:71-81. [PMID: 38573177 PMCID: PMC11027024 DOI: 10.1080/13543776.2024.2338099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/15/2024] [Indexed: 04/05/2024]
Abstract
INTRODUCTION The neuropeptide relaxin-3/RXFP3 system belongs to the relaxin/insulin superfamily and is involved in many important physiological processes, such as stress responses, appetite control, and motivation for reward. Although relaxin-3 is the endogenous agonist for RXFP3, it can also bind to and activate RXFP1 and RXFP4. Consequently, research has been focused on the development of RXFP3-specific peptides and small-molecule ligands to validate the relaxin-3/RXFP3 system as a novel drug target. AREAS COVERED This review provides an overview of patents on the relaxin-3/RXFP3 system covering ligand development and pharmacological studies since 2003. Related patents and literature reports were obtained from established sources including SciFinder, Google Patents, and Espacenet for patents and SciFinder, PubMed, and Google Scholar for literature reports. EXPERT OPINION There has been an increasing amount of patent activities around relaxin-3/RXFP3, highlighting the importance of this novel neuropeptide system for drug discovery. The development of relaxin-3 derived peptides and small-molecule modulators, as well as behavioral studies in rodents, have shown that the relaxin-3/RXFP3 system is a promising drug target for treating various metabolic and neuropsychiatric diseases including obesity, anxiety, and alcohol addiction.
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Affiliation(s)
- Md Toufiqur Rahman
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC, USA
| | | | - Javeena Hussain
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC, USA
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC, USA
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Chen D, Rehfeld JF, Watts AG, Rorsman P, Gundlach AL. History of key regulatory peptide systems and perspectives for future research. J Neuroendocrinol 2023; 35:e13251. [PMID: 37053148 DOI: 10.1111/jne.13251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023]
Abstract
Throughout the 20th Century, regulatory peptide discovery advanced from the identification of gut hormones to the extraction and characterization of hypothalamic hypophysiotropic factors, and to the isolation and cloning of multiple brain neuropeptides. These discoveries were followed by the discovery of G-protein-coupled and other membrane receptors for these peptides. Subsequently, the systems physiology associated with some of these multiple regulatory peptides and receptors has been comprehensively elucidated and has led to improved therapeutics and diagnostics and their approval by the US Food and Drug Administration. In light of this wealth of information and further potential, it is truly a time of renaissance for regulatory peptides. In this perspective, we review what we have learned from the pioneers in exemplified fields of gut peptides, such as cholecystokinin, enterochromaffin-like-cell peptides, and glucagon, from the trailblazing studies on the key stress hormone, corticotropin-releasing factor, as well as from more recently characterized relaxin-family peptides and receptors. The historical viewpoints are based on our understanding of these topics in light of the earliest phases of research and on subsequent studies and the evolution of knowledge, aiming to sharpen our vision of the current state-of-the-art and those studies that should be prioritized in the future.
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Affiliation(s)
- Duan Chen
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Alan G Watts
- Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California, USA
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
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Van Voorhies KJ, Liu W, Lovelock DF, Lin S, Liu J, Guan D, Gay EA, Jin C, Besheer J. Novel RXFP3 negative allosteric modulator RLX-33 reduces alcohol self-administration in rats. J Neurochem 2023; 167:204-217. [PMID: 37674350 PMCID: PMC10592109 DOI: 10.1111/jnc.15949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 09/08/2023]
Abstract
There is much interest in identifying novel pharmacotherapeutic targets that improve clinical outcomes for the treatment of alcohol use disorder (AUD). One promising target for therapeutic intervention is the relaxin family peptide 3 (RXFP3) receptor, a cognate receptor for neuropeptide relaxin-3, which has previously been implicated in regulating alcohol drinking behavior. Recently, we developed the first small-molecule RXFP3-selective negative allosteric modulator (NAM) RLX-33. Therefore, the goal of the present work was to characterize the impact of this novel NAM on affective-related behaviors and alcohol self-administration in rats. First, the effects of RLX-33 were tested on alcohol and sucrose self-administration in Wistar and alcohol-preferring P rats to determine the dose-response profile and specificity for alcohol. Then, we assessed the effects of systemic RLX-33 injection in Wistar rats in a battery of behavioral assays (open-field test, elevated zero maze, acoustic startle response test, and prepulse inhibition) and tested for alcohol clearance. We found that the lowest effective dose (5 mg/kg) reduced alcohol self-administration in both male and female Wistar rats, while in alcohol-preferring P rats, this effect was restricted to males, and there were no effects on sucrose self-administration or general locomotor activity. The characterization of affective and metabolic effects in Wistar rats generally found few locomotor, affective, or alcohol clearance changes, particularly at the 5 mg/kg dose. Overall, these findings are promising and suggest that RXFP3 NAM has potential as a pharmacological target for treating AUD.
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Affiliation(s)
- Kalynn J. Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Wen Liu
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Dennis F. Lovelock
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Sophia Lin
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jiaqi Liu
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Dongliang Guan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Elaine A. Gay
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Lv C, Zheng H, Jiang B, Ren Q, Zhang J, Zhang X, Li J, Wang Y. Characterization of relaxin 3 and its receptors in chicken: Evidence for relaxin 3 acting as a novel pituitary hormone. Front Physiol 2022; 13:1010851. [DOI: 10.3389/fphys.2022.1010851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
Mammalian relaxin (RLN) family peptides binding their receptors (RXFPs) play a variety of roles in many physiological processes, such as reproduction, stress, appetite regulation, and energy balance. In birds, although two relaxin family peptides (RLN3 and INSL5) and four receptors (RXFP1, RXFP2, RXFP2-like, and RXFP3) were predicated, their sequence features, signal properties, tissue distribution, and physiological functions remain largely unknown. In this study, using chickens as the experimental model, we cloned the cDNA of the cRLN3 gene and two receptor (cRXFP1 and cRXFP3) genes. Using cell-based luciferase reporter assays, we demonstrate that cRLN3 is able to activate both cRXFP1 and cRXFP3 for downstream signaling. cRXFP1, rather than cRXFP3, is a cognate receptor for cRLN3, which is different from the mammals. Tissue distribution analyses reveal that cRLN3 is highly expressed in the pituitary with lower abundance in the hypothalamus and ovary of female chicken, together with the detection that cRLN3 co-localizes with pituitary hormone genes LHB/FSHB/GRP/CART and its expression is tightly regulated by hypothalamic factors (GnRH and CRH) and sex steroid hormone (E2). The present study supports that cRLN3 may function as a novel pituitary hormone involving female reproduction.
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Gay EA, Guan D, Van Voorhies K, Vasukuttan V, Mathews KM, Besheer J, Jin C. Discovery and Characterization of the First Nonpeptide Antagonists for the Relaxin-3/RXFP3 System. J Med Chem 2022; 65:7959-7974. [PMID: 35594150 DOI: 10.1021/acs.jmedchem.2c00508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The neuropeptide relaxin-3/RXFP3 system is involved in many important physiological processes such as stress responses, appetite control, and motivation for reward. To date, pharmacological studies of RXFP3 have been limited to peptide ligands. In this study, we report the discovery of the first small-molecule antagonists of RXFP3 through a high-throughput screening campaign. Focused structure-activity relationship studies of the hit compound resulted in RLX-33 (33) that was able to inhibit relaxin-3 activity in a battery of functional assays. RLX-33 is selective for RXFP3 over RXFP1 and RXFP4, two related members in the relaxin/insulin superfamily, and has favorable pharmacokinetic properties for behavioral assessment. When administered to rats intraperitoneally, RLX-33 blocked food intake induced by the RXFP3-selective agonist R3/I5. Collectively, our findings demonstrated that RLX-33 represents a promising antagonist scaffold for the development of drugs targeting the relaxin-3/RXFP3 system.
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Affiliation(s)
- Elaine A Gay
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Dongliang Guan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Vineetha Vasukuttan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Kelly M Mathews
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
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Leysen H, Walter D, Clauwaert L, Hellemans L, van Gastel J, Vasudevan L, Martin B, Maudsley S. The Relaxin-3 Receptor, RXFP3, Is a Modulator of Aging-Related Disease. Int J Mol Sci 2022; 23:4387. [PMID: 35457203 PMCID: PMC9027355 DOI: 10.3390/ijms23084387] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 12/12/2022] Open
Abstract
During the aging process our body becomes less well equipped to deal with cellular stress, resulting in an increase in unrepaired damage. This causes varying degrees of impaired functionality and an increased risk of mortality. One of the most effective anti-aging strategies involves interventions that combine simultaneous glucometabolic support with augmented DNA damage protection/repair. Thus, it seems prudent to develop therapeutic strategies that target this combinatorial approach. Studies have shown that the ADP-ribosylation factor (ARF) GTPase activating protein GIT2 (GIT2) acts as a keystone protein in the aging process. GIT2 can control both DNA repair and glucose metabolism. Through in vivo co-regulation analyses it was found that GIT2 forms a close coexpression-based relationship with the relaxin-3 receptor (RXFP3). Cellular RXFP3 expression is directly affected by DNA damage and oxidative stress. Overexpression or stimulation of this receptor, by its endogenous ligand relaxin 3 (RLN3), can regulate the DNA damage response and repair processes. Interestingly, RLN3 is an insulin-like peptide and has been shown to control multiple disease processes linked to aging mechanisms, e.g., anxiety, depression, memory dysfunction, appetite, and anti-apoptotic mechanisms. Here we discuss the molecular mechanisms underlying the various roles of RXFP3/RLN3 signaling in aging and age-related disorders.
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Affiliation(s)
- Hanne Leysen
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
| | - Deborah Walter
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
| | - Lore Clauwaert
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
| | - Lieselot Hellemans
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
| | - Jaana van Gastel
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
- SGS Belgium, Intercity Business Park, Generaal De Wittelaan 19-A5, 2800 Mechelen, Belgium
| | | | - Bronwen Martin
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium;
| | - Stuart Maudsley
- Receptor Biology Laboratory, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (L.C.); (L.H.); (J.v.G.)
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11
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Wong WLE, Dawe GS, Young AH. The putative role of the relaxin-3/RXFP3 system in clinical depression and anxiety: A systematic literature review. Neurosci Biobehav Rev 2021; 131:429-450. [PMID: 34537263 DOI: 10.1016/j.neubiorev.2021.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 12/14/2022]
Abstract
The relaxin-3/RXFP3 system is one of several neuropeptidergic systems putatively implicated in regulating the behavioural alterations that characterise clinical depression and anxiety, making it a potential target for clinical translation. Accordingly, this systematic review identified published reports on the role of relaxin-3/RXFP3 signalling in these neuropsychiatric disorders and their behavioural endophenotypes, evaluating evidence from animal and human studies to ascertain any relationship. We searched PubMed, EMBASE, PsycINFO and Google Scholar databases up to February 2021, finding 609 relevant records. After stringent screening, 51 of these studies were included in the final synthesis. There was considerable heterogeneity in study designs and some inconsistency across study outcomes. However, experimental evidence is consistent with an ability of relaxin-3/RXFP3 signalling to promote arousal and suppress depressive- and anxiety-like behaviour. Moreover, meta-analyses of six to eight articles investigating food intake revealed that acute RXFP3 activation had strong orexigenic effects in rats. This appraisal also identified the lack of high-quality clinical studies pertinent to the relaxin-3/RXFP3 system, a gap that future research should attempt to bridge.
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Affiliation(s)
- Win Lee Edwin Wong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
| | - Gavin Stewart Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore
| | - Allan H Young
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom; South London & Maudsley NHS Foundation Trust, Bethlem Royal Hospital, Monks Orchard Road, London, United Kingdom
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12
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Walker LC, Huckstep KL, Chen NA, Hand LJ, Lindsley CW, Langmead CJ, Lawrence AJ. Muscarinic M 4 and M 5 receptors in the ventral subiculum differentially modulate alcohol seeking versus consumption in male alcohol-preferring rats. Br J Pharmacol 2021; 178:3730-3746. [PMID: 33942300 DOI: 10.1111/bph.15513] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/11/2021] [Accepted: 04/20/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Muscarinic acetylcholine receptors mediate alcohol consumption and seeking in rats. While M4 and M5 receptors have recently been implicated to mediate these behaviours in the striatum, their role in other brain regions remain unknown. The ventral tegmental area (VTA) and ventral subiculum (vSub) both densely express M4 and M5 receptors and modulate alcohol-seeking, via their projections to the nucleus accumbens shell (AcbSh). EXPERIMENTAL APPROACH In Indiana alcohol-preferring (iP) male rats, we examined Chrm4 (M4 ) and Chrm5 (M5 ) expression in the VTA and vSub following long-term alcohol consumption and abstinence using RT-qPCR. Using a combination of retrograde tracing and RNAscope, we examined the localisation of Chrm4 and Chrm5 on vSub cells that project to the AcbSh. Using selective allosteric modulators, we examined the functional role of M4 and M5 receptors within the vSub in alcohol consumption, context-induced alcohol-seeking, locomotor activity, and food/water consumption. KEY RESULTS Long-term alcohol and abstinence dysregulated the expression of genes for muscarinic receptors in the vSub, not in the VTA. Chrm4 was down-regulated following long-term alcohol and abstinence, while Chrm5 was up-regulated following long-term alcohol consumption. Consistent with these data, a positive allosteric modulator (VU0467154) of intra-vSub M4 receptors reduced context-induced alcohol-seeking, but not motivation for alcohol self-administration, while M5 receptor negative allosteric modulator (ML375) reduced initial motivation for alcohol self-administration, but not context-induced alcohol-seeking. CONCLUSION AND IMPLICATIONS Collectively, our data highlight alcohol-induced cholinergic dysregulation in the vSub and distinct roles for M4 and M5 receptor allosteric modulators to reduce alcohol consumption or seeking.
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Affiliation(s)
- Leigh C Walker
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Kate L Huckstep
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Nicola A Chen
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Lexi J Hand
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Craig W Lindsley
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, USA
| | - Christopher J Langmead
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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13
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Gil-Miravet I, Mañas-Ojeda A, Ros-Bernal F, Castillo-Gómez E, Albert-Gascó H, Gundlach AL, Olucha-Bordonau FE. Involvement of the Nucleus Incertus and Relaxin-3/RXFP3 Signaling System in Explicit and Implicit Memory. Front Neuroanat 2021; 15:637922. [PMID: 33867946 PMCID: PMC8044989 DOI: 10.3389/fnana.2021.637922] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/26/2021] [Indexed: 12/18/2022] Open
Abstract
Telencephalic cognitive and emotional circuits/functions are strongly modulated by subcortical inputs. The main focus of past research on the nature of this modulation has been on the widespread monoamine projections to the telencephalon. However, the nucleus incertus (NI) of the pontine tegmentum provides a strong GABAergic and peptidergic innervation of the hippocampus, basal forebrain, amygdala, prefrontal cortex, and related regions; and represents a parallel source of ascending modulation of cognitive and emotional domains. NI GABAergic neurons express multiple peptides, including neuromedin-B, cholecystokinin, and relaxin-3, and receptors for stress and arousal transmitters, including corticotrophin-releasing factor and orexins/hypocretins. A functional relationship exists between NI neurons and their associated peptides, relaxin-3 and neuromedin-B, and hippocampal theta rhythm, which in turn, has a key role in the acquisition and extinction of declarative and emotional memories. Furthermore, RXFP3, the cognate receptor for relaxin-3, is a Gi/o protein-coupled receptor, and its activation inhibits the cellular accumulation of cAMP and induces phosphorylation of ERK, processes associated with memory formation in the hippocampus and amygdala. Therefore, this review summarizes the role of NI transmitter systems in relaying stress- and arousal-related signals to the higher neural circuits and processes associated with memory formation and retrieval.
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Affiliation(s)
- Isis Gil-Miravet
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castelló de la Plana, Spain
| | - Aroa Mañas-Ojeda
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castelló de la Plana, Spain
| | - Francisco Ros-Bernal
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castelló de la Plana, Spain
| | - Esther Castillo-Gómez
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castelló de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain
| | - Hector Albert-Gascó
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge, United Kingdom
| | - Andrew L Gundlach
- The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Francisco E Olucha-Bordonau
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castelló de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain
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14
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Walker LC. A balancing act: the role of pro- and anti-stress peptides within the central amygdala in anxiety and alcohol use disorders. J Neurochem 2021; 157:1615-1643. [PMID: 33450069 DOI: 10.1111/jnc.15301] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/18/2020] [Accepted: 01/06/2021] [Indexed: 12/21/2022]
Abstract
The central nucleus of the amygdala (CeA) is widely implicated as a structure that integrates both appetitive and aversive stimuli. While intrinsic CeA microcircuits primarily consist of GABAergic neurons that regulate amygdala output, a notable feature of the CeA is the heterogeneity of neuropeptides and neuropeptide/neuromodulator receptors that it expresses. There is growing interest in the role of the CeA in mediating psychopathologies, including stress and anxiety states and their interactions with alcohol use disorders. Within the CeA, neuropeptides and neuromodulators often exert pro- or anti- stress actions, which can influence anxiety and alcohol associated behaviours. In turn, alcohol use can cause adaptions within the CeA, which may render an individual more vulnerable to stress which is a major trigger of relapse to alcohol seeking. This review examines the neurocircuitry, neurochemical phenotypes and how pro- and anti-stress peptide systems act within the CeA to regulate anxiety and alcohol seeking, focusing on preclinical observations from animal models. Furthermore, literature exploring the targeting of genetically defined populations or neuronal ensembles and the role of the CeA in mediating sex differences in stress x alcohol interactions are explored.
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Affiliation(s)
- Leigh C Walker
- Florey Institute of Neuroscience and Mental Health, Parkville, Vic, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Vic, Australia
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15
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de Ávila C, Chometton S, Calvez J, Guèvremont G, Kania A, Torz L, Lenglos C, Blasiak A, Rosenkilde MM, Holst B, Conrad CD, Fryer JD, Timofeeva E, Gundlach AL, Cifani C. Estrous Cycle Modulation of Feeding and Relaxin-3/Rxfp3 mRNA Expression: Implications for Estradiol Action. Neuroendocrinology 2021; 111:1201-1218. [PMID: 33333517 DOI: 10.1159/000513830] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/14/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Food intake varies during the ovarian hormone/estrous cycle in humans and rodents, an effect mediated mainly by estradiol. A potential mediator of the central anorectic effects of estradiol is the neuropeptide relaxin-3 (RLN3) synthetized in the nucleus incertus (NI) and acting via the relaxin family peptide-3 receptor (RXFP3). METHODS We investigated the relationship between RLN3/RXFP3 signaling and feeding behavior across the female rat estrous cycle. We used in situ hybridization to investigate expression patterns of Rln3 mRNA in NI and Rxfp3 mRNA in the hypothalamic paraventricular nucleus (PVN), lateral hypothalamic area (LHA), medial preoptic area (MPA), and bed nucleus of the stria terminalis (BNST), across the estrous cycle. We identified expression of estrogen receptors (ERs) in the NI using droplet digital PCR and assessed the electrophysiological responsiveness of NI neurons to estradiol in brain slices. RESULTS Rln3 mRNA reached the lowest levels in the NI pars compacta during proestrus. Rxfp3 mRNA levels varied across the estrous cycle in a region-specific manner, with changes observed in the perifornical LHA, magnocellular PVN, dorsal BNST, and MPA, but not in the parvocellular PVN or lateral LHA. G protein-coupled estrogen receptor 1 (Gper1) mRNA was the most abundant ER transcript in the NI. Estradiol inhibited 33% of type 1 NI neurons, including RLN3-positive cells. CONCLUSION These findings demonstrate that the RLN3/RXFP3 system is modulated by the estrous cycle, and although further studies are required to better elucidate the cellular and molecular mechanisms of estradiol signaling, current results implicate the involvement of the RLN3/RXFP3 system in food intake fluctuations observed across the estrous cycle in female rats.
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Affiliation(s)
- Camila de Ávila
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada,
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark,
- Department of Neuroscience, Mayo Clinic, Scottsdale, Arizona, USA,
- Department of Psychology, Arizona State University, Tempe, Arizona, USA,
| | - Sandrine Chometton
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
| | - Juliane Calvez
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
| | - Geneviève Guèvremont
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
| | - Alan Kania
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Lola Torz
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF CBMR, Nutrient and Metabolite Sensing, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Christophe Lenglos
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF CBMR, Nutrient and Metabolite Sensing, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Cheryl D Conrad
- Department of Psychology, Arizona State University, Tempe, Arizona, USA
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Scottsdale, Arizona, USA
| | - Elena Timofeeva
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Carlo Cifani
- Department of Psychiatry and Neuroscience, Faculty of Medicine, CRIUCPQ, Université Laval, Québec, Québec, Canada
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
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16
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Lee HS, Wang SH, Daniel JT, Hossain MA, Clark RJ, Bathgate RAD, Rosengren KJ. Exploring the Use of Helicogenic Amino Acids for Optimising Single Chain Relaxin-3 Peptide Agonists. Biomedicines 2020; 8:biomedicines8100415. [PMID: 33066369 PMCID: PMC7602263 DOI: 10.3390/biomedicines8100415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 11/16/2022] Open
Abstract
Relaxin-3 is a highly conserved two-chain neuropeptide that acts through its endogenous receptor the Relaxin Family Peptide-3 (RXFP3) receptor. The ligand/receptor system is known to modulate several physiological processes, with changes in food intake and anxiety-levels the most well studied in rodent models. Agonist and antagonist analogues based on the native two-chain peptide are costly to synthesise and not ideal drug leads. Since RXFP3 interacting residues are found in the relaxin B-chain only, this has been the focus of analogue development. The B-chain is unstructured without the A-chain support, but in single-chain variants structure can be induced by dicarba-based helical stapling strategies. Here we investigated whether alternative helical inducing strategies also can enhance structure and activity at RXFP3. Combinations of the helix inducing α-aminoisobutyric acid (Aib) were incorporated into the sequence of the relaxin-3 B-chain. Aib residues at positions 13, 17 and 18 partially reintroduce helicity and activity of the relaxin-3 B-chain, but other positions are generally not suited for modifications. We identify Thr21 as a putative new receptor contact residue important for RXFP3 binding. Cysteine residues were also incorporated into the sequence and cross-linked with dichloroacetone or α, α'-dibromo-m-xylene. However, in contrast to previously reported dicarba variants, neither were found to promote structure and RXFP3 activity.
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Affiliation(s)
- Han Siean Lee
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia; (H.S.L.); (S.H.W.); (J.T.D.); (R.J.C.)
| | - Shu Hui Wang
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia; (H.S.L.); (S.H.W.); (J.T.D.); (R.J.C.)
| | - James T. Daniel
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia; (H.S.L.); (S.H.W.); (J.T.D.); (R.J.C.)
| | - Mohammed Akhter Hossain
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC 3052, Australia; (M.A.H.); (R.A.D.B.)
- School of Chemistry, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Richard J. Clark
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia; (H.S.L.); (S.H.W.); (J.T.D.); (R.J.C.)
| | - Ross A. D. Bathgate
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC 3052, Australia; (M.A.H.); (R.A.D.B.)
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - K. Johan Rosengren
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia; (H.S.L.); (S.H.W.); (J.T.D.); (R.J.C.)
- Correspondence:
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17
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de Ávila C, Chometton S, Ma S, Pedersen LT, Timofeeva E, Cifani C, Gundlach AL. Effects of chronic silencing of relaxin-3 production in nucleus incertus neurons on food intake, body weight, anxiety-like behaviour and limbic brain activity in female rats. Psychopharmacology (Berl) 2020; 237:1091-1106. [PMID: 31897576 DOI: 10.1007/s00213-019-05439-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 12/17/2019] [Indexed: 10/25/2022]
Abstract
Eating disorders are frequently triggered by stress and are more prevalent in women than men. First signs often appear during early adolescence, but the biological basis for the sex-specific differences is unknown. Central administration of native relaxin-3 (RLN3) peptide or chimeric/truncated analogues produces differential effects on food intake and HPA axis activity in adult male and female rats, but the precise role of endogenous RLN3 signalling in metabolic and neuroendocrine control is unclear. Therefore, we examined the effects of microRNA-induced depletion (knock-down) of RLN3 mRNA/(peptide) production in neurons of the brainstem nucleus incertus (NI) in female rats on a range of physiological, behavioural and neurochemical indices, including food intake, body weight, anxiety, plasma corticosterone, mRNA levels of key neuropeptides in the paraventricular nucleus of hypothalamus (PVN) and limbic neural activity patterns (reflected by c-fos mRNA). Validated depletion of RLN3 in NI neurons of female rats (n = 8) produced a small, sustained (~ 2%) decrease in body weight, an imbalance in food intake and an increase in anxiety-like behaviour in the large open field, but not in the elevated plus-maze or light/dark box. Furthermore, NI RLN3 depletion disrupted corticosterone regulation, increased oxytocin and arginine-vasopressin, but not corticotropin-releasing factor, mRNA, in PVN, and decreased basal levels of c-fos mRNA in parvocellular and magnocellular PVN, bed nucleus of stria terminalis and the lateral hypothalamic area, brain regions involved in stress and feeding. These findings support a role for NI RLN3 neurons in fine-tuning stress and neuroendocrine responses and food intake regulation in female rats.
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Affiliation(s)
- Camila de Ávila
- Department of Psychiatry and Neuroscience, CRIUCPQ, Faculty of Medicine, Université Laval, Québec, Canada. .,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia. .,NNF CBMR, Nutrient and Metabolite Sensing, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark.
| | - Sandrine Chometton
- Department of Psychiatry and Neuroscience, CRIUCPQ, Faculty of Medicine, Université Laval, Québec, Canada
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Lola Torz Pedersen
- NNF CBMR, Nutrient and Metabolite Sensing, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Elena Timofeeva
- Department of Psychiatry and Neuroscience, CRIUCPQ, Faculty of Medicine, Université Laval, Québec, Canada
| | - Carlo Cifani
- Department of Psychiatry and Neuroscience, CRIUCPQ, Faculty of Medicine, Université Laval, Québec, Canada.,Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.
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18
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Genders SG, Scheller KJ, Djouma E. Neuropeptide modulation of addiction: Focus on galanin. Neurosci Biobehav Rev 2020; 110:133-149. [DOI: 10.1016/j.neubiorev.2018.06.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/07/2018] [Accepted: 06/21/2018] [Indexed: 12/12/2022]
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19
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Lee HS, Postan M, Song A, Clark RJ, Bathgate RAD, Haugaard-Kedström LM, Rosengren KJ. Development of Relaxin-3 Agonists and Antagonists Based on Grafted Disulfide-Stabilized Scaffolds. Front Chem 2020; 8:87. [PMID: 32133341 PMCID: PMC7039932 DOI: 10.3389/fchem.2020.00087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 01/27/2020] [Indexed: 12/22/2022] Open
Abstract
Relaxin-3 is a neuropeptide with important roles in metabolism, arousal, learning and memory. Its cognate receptor is the relaxin family peptide-3 (RXFP3) receptor. Relaxin-3 agonist and antagonist analogs have been shown to be able to modulate food intake in rodent models. The relaxin-3 B-chain is sufficient for receptor interactions, however, in the absence of a structural support, linear relaxin-3 B-chain analogs are rapidly degraded and thus unsuitable as drug leads. In this study, two different disulfide-stabilized scaffolds were used for grafting of important relaxin-3 B-chain residues to improve structure and stability. The use of both Veronica hederifolia Trypsin inhibitor (VhTI) and apamin grafting resulted in agonist and antagonist analogs with improved helicity. VhTI grafted peptides showed poor binding and low potency at RXFP3, on the other hand, apamin variants retained significant activity. These variants also showed improved half-life in serum from ~5 min to >6 h, and thus are promising RXFP3 specific pharmacological tools and drug leads for neuropharmacological diseases.
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Affiliation(s)
- Han Siean Lee
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Michael Postan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Angela Song
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Richard J Clark
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Ross A D Bathgate
- Florey Department of Neuroscience and Mental Health, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia.,Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Linda M Haugaard-Kedström
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - K Johan Rosengren
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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20
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Walker LC, Kastman HE, Lawrence AJ. Pattern of neural activation following yohimbine‐induced reinstatement of alcohol seeking in rats. Eur J Neurosci 2020; 51:706-720. [DOI: 10.1111/ejn.14431] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/25/2019] [Accepted: 04/23/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Leigh C. Walker
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
- Florey Department of Neuroscience and Mental Health The University of Melbourne Melbourne Victoria Australia
| | - Hanna E. Kastman
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Andrew J. Lawrence
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
- Florey Department of Neuroscience and Mental Health The University of Melbourne Melbourne Victoria Australia
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21
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van Gastel J, Leysen H, Santos-Otte P, Hendrickx JO, Azmi A, Martin B, Maudsley S. The RXFP3 receptor is functionally associated with cellular responses to oxidative stress and DNA damage. Aging (Albany NY) 2019; 11:11268-11313. [PMID: 31794429 PMCID: PMC6932917 DOI: 10.18632/aging.102528] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/18/2019] [Indexed: 12/19/2022]
Abstract
DNA damage response (DDR) processes, often caused by oxidative stress, are important in aging and -related disorders. We recently showed that G protein-coupled receptor (GPCR) kinase interacting protein 2 (GIT2) plays a key role in both DNA damage and oxidative stress. Multiple tissue analyses in GIT2KO mice demonstrated that GIT2 expression affects the GPCR relaxin family peptide 3 receptor (RXFP3), and is thus a therapeutically-targetable system. RXFP3 and GIT2 play similar roles in metabolic aging processes. Gaining a detailed understanding of the RXFP3-GIT2 functional relationship could aid the development of novel anti-aging therapies. We determined the connection between RXFP3 and GIT2 by investigating the role of RXFP3 in oxidative stress and DDR. Analyzing the effects of oxidizing (H2O2) and DNA-damaging (camptothecin) stressors on the interacting partners of RXFP3 using Affinity Purification-Mass Spectrometry, we found multiple proteins linked to DDR and cell cycle control. RXFP3 expression increased in response to DNA damage, overexpression, and Relaxin 3-mediated stimulation of RXFP3 reduced phosphorylation of DNA damage marker H2AX, and repair protein BRCA1, moderating DNA damage. Our data suggests an RXFP3-GIT2 system that could regulate cellular degradation after DNA damage, and could be a novel mechanism for mitigating the rate of age-related damage accumulation.
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Affiliation(s)
- Jaana van Gastel
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Hanne Leysen
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Paula Santos-Otte
- Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
| | - Jhana O Hendrickx
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Abdelkrim Azmi
- Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Bronwen Martin
- Faculty of Pharmaceutical, Veterinary and Biomedical Science, University of Antwerp, Antwerp, Belgium
| | - Stuart Maudsley
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
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22
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Alnafea H, Vahkal B, Zelmer CK, Yegorov S, Bogerd J, Good SV. Japanese medaka as a model for studying the relaxin family genes involved in neuroendocrine regulation: Insights from the expression of fish-specific rln3 and insl5 and rxfp3/4-type receptor paralogues. Mol Cell Endocrinol 2019; 487:2-11. [PMID: 30703485 DOI: 10.1016/j.mce.2019.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/17/2019] [Accepted: 01/19/2019] [Indexed: 12/14/2022]
Abstract
The goal of this paper is to establish Japanese medaka (Oryzias latipes) as a model for relaxin family peptide research, particularly for studying the functions of RLN3 and INSL5, hormones playing roles in neuroendocrine regulation. Medaka, like other teleosts, retained duplicate copies of rln3, insl5 and their rxfp3/4-type receptors following fish-specific whole genome duplication (WGD) and paralogous copies of these genes may have sub-functionalised providing an intuitive model for teasing apart the pleiotropic roles of the corresponding genes in mammals. To this end, we provide experimental evidence for the expression of the relaxin family genes in medaka that had previously only been identified in-silico, confirm the gene structure of five of the ligand genes, characterise gene expression across multiple tissues and during embryonic development, perform in situ hybridization with anti-sense insl5a on embryos and in adult brain and intestinal samples, and compare these results to the data available in zebrafish. We find broad similarities but also some differences in the expression of relaxin family genes in zebrafish versus medaka, and find support for the hypothesis that the rln3a/rln3b and insl5a/insl5b paralogues have been subfunctionalized. Given that medaka has a suite of relaxin family genes more similar to other teleosts, and has retained the gene for rxfp4 (which is lost in zebrafish), our results suggest that O. latipes may be a good model for delineating the ancestral function of the relaxin family genes involved in neuroendocrine regulation.
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Affiliation(s)
- Hend Alnafea
- Department of Biology, The University of Winnipeg, Winnipeg, MB, Canada
| | - Brett Vahkal
- Department of Biology, The University of Winnipeg, Winnipeg, MB, Canada
| | - C Kellie Zelmer
- Department of Biology, The University of Winnipeg, Winnipeg, MB, Canada
| | - Sergey Yegorov
- Department of Immunology, The University of Toronto, Toronto, ON, Canada
| | - Jan Bogerd
- Reproductive Biology Group, Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Sara V Good
- Department of Biology, The University of Winnipeg, Winnipeg, MB, Canada; Department of Biology, The University of Manitoba, Winnipeg, MB, Canada.
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23
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Ch'ng SS, Fu J, Brown RM, Smith CM, Hossain MA, McDougall SJ, Lawrence AJ. Characterization of the relaxin family peptide receptor 3 system in the mouse bed nucleus of the stria terminalis. J Comp Neurol 2019; 527:2615-2633. [PMID: 30947365 DOI: 10.1002/cne.24695] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/19/2019] [Accepted: 03/27/2019] [Indexed: 01/17/2023]
Abstract
The bed nucleus of the stria terminalis (BNST) is a critical node involved in stress and reward-related behaviors. Relaxin family peptide receptor 3 (RXFP3) signaling in the BNST has been implicated in stress-induced alcohol seeking behavior. However, the neurochemical phenotype and connectivity of BNST RXFP3-expressing (RXFP3+) cells have yet to be elucidated. We interrogated the molecular signature and electrophysiological properties of BNST RXFP3+ neurons using a RXFP3-Cre reporter mouse line. BNST RXFP3+ cells are circumscribed to the dorsal BNST (dBNST) and are neurochemically heterogeneous, comprising a mix of inhibitory and excitatory neurons. Immunohistochemistry revealed that ~48% of BNST RXFP3+ neurons are GABAergic, and a quarter of these co-express the calcium-binding protein, calbindin. A subset of BNST RXFP3+ cells (~41%) co-express CaMKIIα, suggesting this subpopulation of BNST RXFP3+ neurons are excitatory. Corroborating this, RNAscope® revealed that ~35% of BNST RXFP3+ cells express vVGluT2 mRNA, indicating a subpopulation of RXFP3+ neurons are glutamatergic. RXFP3+ neurons show direct hyperpolarization to bath application of a selective RXFP3 agonist, RXFP3-A2, while around 50% of cells were depolarised by exogenous corticotrophin releasing factor. In behaviorally naive mice the majority of RXFP3+ neurons were Type II cells exhibiting Ih and T type calcium mediated currents. However, chronic swim stress caused persistent plasticity, decreasing the proportion of neurons that express these channels. These studies are the first to characterize the BNST RXFP3 system in mouse and lay the foundation for future functional studies appraising the role of the murine BNST RXFP3 system in more complex behaviors.
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Affiliation(s)
- Sarah S Ch'ng
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Jingjing Fu
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Craig M Smith
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | | | - Stuart J McDougall
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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24
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Rytova V, Ganella DE, Hawkes D, Bathgate RAD, Ma S, Gundlach AL. Chronic activation of the relaxin-3 receptor on GABA neurons in rat ventral hippocampus promotes anxiety and social avoidance. Hippocampus 2019; 29:905-920. [PMID: 30891856 DOI: 10.1002/hipo.23089] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 12/24/2022]
Abstract
Anxiety disorders are highly prevalent in modern society and better treatments are required. Key brain areas and signaling systems underlying anxiety include prefrontal cortex, hippocampus, and amygdala, and monoaminergic and peptidergic systems, respectively. Hindbrain GABAergic projection neurons that express the peptide, relaxin-3, broadly innervate the forebrain, particularly the septum and hippocampus, and relaxin-3 acts via a Gi/o -protein-coupled receptor known as the relaxin-family peptide 3 receptor (RXFP3). Thus, relaxin-3/RXFP3 signaling is implicated in modulation of arousal, motivation, mood, memory, and anxiety. Ventral hippocampus (vHip) is central to affective and cognitive processing and displays a high density of relaxin-3-positive nerve fibers and RXFP3 binding sites, but the identity of target neurons and associated effects on behavior are unknown. Therefore, in adult, male rats, we assessed the neurochemical nature of hippocampal RXFP3 mRNA-expressing neurons and anxiety-like and social behavior following chronic RXFP3 activation in vHip by viral vector expression of an RXFP3-selective agonist peptide, R3/I5. RXFP3 mRNA detected by fluorescent in situ hybridization was topographically distributed across the hippocampus in somatostatin- and parvalbumin-mRNA expressing GABA neurons. Chronic RXFP3 activation in vHip increased anxiety-like behavior in the light-dark box and elevated-plus maze, but not the large open-field test, and reduced social interaction with a conspecific stranger. Our data reveal disruptive effects of persistent RXFP3 signaling on hippocampal GABA networks important in anxiety; and identify a potential therapeutic target for anxiety disorders that warrants further investigation in relevant preclinical models.
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Affiliation(s)
- Valeria Rytova
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Despina E Ganella
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - David Hawkes
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Ross A D Bathgate
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sherie Ma
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew L Gundlach
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
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25
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Ch'ng S, Fu J, Brown RM, McDougall SJ, Lawrence AJ. The intersection of stress and reward: BNST modulation of aversive and appetitive states. Prog Neuropsychopharmacol Biol Psychiatry 2018; 87:108-125. [PMID: 29330137 DOI: 10.1016/j.pnpbp.2018.01.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/27/2017] [Accepted: 01/08/2018] [Indexed: 12/13/2022]
Abstract
The bed nucleus of the stria terminalis (BNST) is widely acknowledged as a brain structure that regulates stress and anxiety states, as well as aversive and appetitive behaviours. The diverse roles of the BNST are afforded by its highly modular organisation, neurochemical heterogeneity, and complex intrinsic and extrinsic circuitry. There has been growing interest in the BNST in relation to psychopathologies such as anxiety and addiction. Although research on the human BNST is still in its infancy, there have been extensive preclinical studies examining the molecular signature and hodology of the BNST and their involvement in stress and reward seeking behaviour. This review examines the neurochemical phenotype and connectivity of the BNST, as well as electrophysiological correlates of plasticity in the BNST mediated by stress and/or drugs of abuse.
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Affiliation(s)
- Sarah Ch'ng
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Jingjing Fu
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Stuart J McDougall
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia.
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26
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Greenwald MK. Anti-stress neuropharmacological mechanisms and targets for addiction treatment: A translational framework. Neurobiol Stress 2018; 9:84-104. [PMID: 30238023 PMCID: PMC6138948 DOI: 10.1016/j.ynstr.2018.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/30/2018] [Accepted: 08/10/2018] [Indexed: 12/18/2022] Open
Abstract
Stress-related substance use is a major challenge for treating substance use disorders. This selective review focuses on emerging pharmacotherapies with potential for reducing stress-potentiated seeking and consumption of nicotine, alcohol, marijuana, cocaine, and opioids (i.e., key phenotypes for the most commonly abused substances). I evaluate neuropharmacological mechanisms in experimental models of drug-maintenance and relapse, which translate more readily to individuals presenting for treatment (who have initiated and progressed). An affective/motivational systems model (three dimensions: valence, arousal, control) is mapped onto a systems biology of addiction approach for addressing this problem. Based on quality of evidence to date, promising first-tier neurochemical receptor targets include: noradrenergic (α1 and β antagonist, α2 agonist), kappa-opioid antagonist, nociceptin antagonist, orexin-1 antagonist, and endocannabinoid modulation (e.g., cannabidiol, FAAH inhibition); second-tier candidates may include corticotropin releasing factor-1 antagonists, serotonergic agents (e.g., 5-HT reuptake inhibitors, 5-HT3 antagonists), glutamatergic agents (e.g., mGluR2/3 agonist/positive allosteric modulator, mGluR5 antagonist/negative allosteric modulator), GABA-promoters (e.g., pregabalin, tiagabine), vasopressin 1b antagonist, NK-1 antagonist, and PPAR-γ agonist (e.g., pioglitazone). To address affective/motivational mechanisms of stress-related substance use, it may be advisable to combine agents with actions at complementary targets for greater efficacy but systematic studies are lacking except for interactions with the noradrenergic system. I note clinically-relevant factors that could mediate/moderate the efficacy of anti-stress therapeutics and identify research gaps that should be pursued. Finally, progress in developing anti-stress medications will depend on use of reliable CNS biomarkers to validate exposure-response relationships.
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Affiliation(s)
- Mark K. Greenwald
- Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA
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27
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Albert-Gasco H, Sanchez-Sarasua S, Ma S, García-Díaz C, Gundlach AL, Sanchez-Perez AM, Olucha-Bordonau FE. Central relaxin-3 receptor (RXFP3) activation impairs social recognition and modulates ERK-phosphorylation in specific GABAergic amygdala neurons. Brain Struct Funct 2018; 224:453-469. [PMID: 30368554 DOI: 10.1007/s00429-018-1763-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/27/2018] [Indexed: 11/25/2022]
Abstract
In mammals, the extended amygdala is a neural hub for social and emotional information processing. In the rat, the extended amygdala receives inhibitory GABAergic projections from the nucleus incertus (NI) in the pontine tegmentum. NI neurons produce the neuropeptide relaxin-3, which acts via the Gi/o-protein-coupled receptor, RXFP3. A putative role for RXFP3 signalling in regulating social interaction was investigated by assessing the effect of intracerebroventricular infusion of the RXFP3 agonist, RXFP3-A2, on performance in the 3-chamber social interaction paradigm. Central RXFP3-A2, but not vehicle, infusion, disrupted the capacity to discriminate between a familiar and novel conspecific subject, but did not alter differentiation between a conspecific and an inanimate object. Subsequent studies revealed that agonist-infused rats displayed increased phosphoERK(pERK)-immunoreactivity in specific amygdaloid nuclei at 20 min post-infusion, with levels similar to control again after 90 min. In parallel, we used immunoblotting to profile ERK phosphorylation dynamics in whole amygdala after RXFP3-A2 treatment; and multiplex histochemical labelling techniques to reveal that after RXFP3-A2 infusion and social interaction, pERK-immunopositive neurons in amygdala expressed vesicular GABA-transporter mRNA and displayed differential profiles of RXFP3 and oxytocin receptor mRNA. Overall, these findings demonstrate that central relaxin-3/RXFP3 signalling can modulate social recognition in rats via effects within the amygdala and likely interactions with GABA and oxytocin signalling.
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MESH Headings
- Amygdala/cytology
- Amygdala/drug effects
- Amygdala/enzymology
- Animals
- Behavior, Animal/drug effects
- Extracellular Signal-Regulated MAP Kinases/metabolism
- GABAergic Neurons/drug effects
- GABAergic Neurons/enzymology
- Infusions, Intraventricular
- Intercellular Signaling Peptides and Proteins
- Male
- Oxytocin/metabolism
- Peptides/administration & dosage
- Phosphorylation
- Rats, Wistar
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Oxytocin/genetics
- Receptors, Oxytocin/metabolism
- Receptors, Peptide/agonists
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Recognition, Psychology/drug effects
- Signal Transduction/drug effects
- Social Behavior
- Vesicular Inhibitory Amino Acid Transport Proteins/genetics
- Vesicular Inhibitory Amino Acid Transport Proteins/metabolism
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Hector Albert-Gasco
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Av de Vicent Sos Baynat, s/n, 12071, Castellón de la Plana, Castellón, Spain
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Sandra Sanchez-Sarasua
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Av de Vicent Sos Baynat, s/n, 12071, Castellón de la Plana, Castellón, Spain
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Cristina García-Díaz
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Av de Vicent Sos Baynat, s/n, 12071, Castellón de la Plana, Castellón, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Ana M Sanchez-Perez
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Av de Vicent Sos Baynat, s/n, 12071, Castellón de la Plana, Castellón, Spain.
| | - Francisco E Olucha-Bordonau
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Av de Vicent Sos Baynat, s/n, 12071, Castellón de la Plana, Castellón, Spain.
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28
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García-Díaz C, Sánchez-Catalán MJ, Castro-Salazar E, García-Avilés A, Albert-Gascó H, Sánchez-Sarasúa de la Bárcena S, Sánchez-Pérez AM, Gundlach AL, Olucha-Bordonau FE. Nucleus incertus ablation disrupted conspecific recognition and modified immediate early gene expression patterns in 'social brain' circuits of rats. Behav Brain Res 2018; 356:332-347. [PMID: 30195021 DOI: 10.1016/j.bbr.2018.08.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/14/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
Social interaction involves neural activity in prefrontal cortex, septum, hippocampus, amygdala and hypothalamus. Notably, these areas all receive projections from the nucleus incertus (NI) in the pontine tegmentum. Therefore, we investigated the effect of excitotoxic lesions of NI neurons in adult male, Wistar rats on performance in a social discrimination test, and associated changes in immediate-early gene protein levels. NI was lesioned with quinolinic acid, and after recovery, rats underwent two trials in the 3-chamber test. In the first trial, NI-lesioned and sham-lesioned rats spent longer exploring a conspecific than an inanimate object. By contrast, in the second trial, NI-lesioned rats visited the familiar and novel conspecific chambers equally, whereas sham-lesioned rats spent longer engaging with the novel rat. Quantification of Fos- and Egr-1-immunoreactivity (IR) levels in brain areas implicated in social behaviour, revealed that social encounter and NI lesion produced complex, differential changes. For example, Egr-1-IR was broadly decreased in several amygdala nuclei in NI-lesioned rats relative to sham, but Fos-IR levels were unaltered. In hippocampus, NI-lesioned rats displayed decreased Fos-IR in CA2 and CA3, while Egr-1-IR was increased in the polymorphic dentate gyrus, CA1, CA2 and subiculum of NI-lesioned rats, relative to sham. Social encounter-related Egr-1-IR was also decreased in septum and anterior and lateral hypothalamus of NI-lesioned rats. Overall, these data suggest NI networks can modulate the activity of sensory, emotional and executive brain areas involved in social recognition, with a likely involvement of neuronal Egr-1 activation in amygdala, septum and hypothalamus, and Erg-1 inhibition in hippocampus.
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Affiliation(s)
| | | | | | | | | | | | | | - A L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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29
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Sabetghadam A, Grabowiecka-Nowak A, Kania A, Gugula A, Blasiak E, Blasiak T, Ma S, Gundlach AL, Blasiak A. Melanin-concentrating hormone and orexin systems in rat nucleus incertus: Dual innervation, bidirectional effects on neuron activity, and differential influences on arousal and feeding. Neuropharmacology 2018; 139:238-256. [DOI: 10.1016/j.neuropharm.2018.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 06/20/2018] [Accepted: 07/04/2018] [Indexed: 12/24/2022]
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30
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Wong LLL, Scott DJ, Hossain MA, Kaas Q, Rosengren KJ, Bathgate RAD. Distinct but overlapping binding sites of agonist and antagonist at the relaxin family peptide 3 (RXFP3) receptor. J Biol Chem 2018; 293:15777-15789. [PMID: 30131340 DOI: 10.1074/jbc.ra118.002645] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/09/2018] [Indexed: 12/22/2022] Open
Abstract
The relaxin-3 neuropeptide activates the relaxin family peptide 3 (RXFP3) receptor to modulate stress, appetite, and cognition. RXFP3 shows promise as a target for treating neurological disorders, but realization of its clinical potential requires development of smaller RXFP3-specific drugs that can penetrate the blood-brain barrier. Designing such drugs is challenging and requires structural knowledge of agonist- and antagonist-binding modes. Here, we used structure-activity data for relaxin-3 and a peptide RXFP3 antagonist termed R3 B1-22R to guide receptor mutagenesis and develop models of their binding modes. RXFP3 residues were alanine-substituted individually and in combination and tested in cell-based binding and functional assays to refine models of agonist and antagonist binding to active- and inactive-state homology models of RXFP3, respectively. These models suggested that both agonists and antagonists interact with RXFP3 via similar residues in their B-chain central helix. The models further suggested that the B-chain Trp27 inserts into the binding pocket of RXFP3 and interacts with Trp138 and Lys271, the latter through a salt bridge with the C-terminal carboxyl group of Trp27 in relaxin-3. R3 B1-22R, which does not contain Trp27, used a non-native Arg23 residue to form cation-π and salt-bridge interactions with Trp138 and Glu141 in RXFP3, explaining a key contribution of Arg23 to affinity. Overall, relaxin-3 and R3 B1-22R appear to share similar binding residues but may differ in binding modes, leading to active and inactive RXFP3 conformational states, respectively. These mechanistic insights may assist structure-based drug design of smaller relaxin-3 mimetics to manage neurological disorders.
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Affiliation(s)
| | - Daniel James Scott
- From the Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Mohammed Akhter Hossain
- From the Florey Institute of Neuroscience and Mental Health.,School of Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia and
| | | | - K Johan Rosengren
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ross A D Bathgate
- From the Florey Institute of Neuroscience and Mental Health, .,Department of Biochemistry and Molecular Biology, and
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31
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Haugaard-Kedström LM, Lee HS, Jones MV, Song A, Rathod V, Hossain MA, Bathgate RAD, Rosengren KJ. Binding conformation and determinants of a single-chain peptide antagonist at the relaxin-3 receptor RXFP3. J Biol Chem 2018; 293:15765-15776. [PMID: 30131342 DOI: 10.1074/jbc.ra118.002611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/27/2018] [Indexed: 12/15/2022] Open
Abstract
The neuropeptide relaxin-3 and its receptor relaxin family peptide receptor-3 (RXFP3) play key roles in modulating behavior such as memory and learning, food intake, and reward seeking. A linear relaxin-3 antagonist (R3 B1-22R) based on a modified and truncated relaxin-3 B-chain was recently developed. R3 B1-22R is unstructured in solution; thus, the binding conformation and determinants of receptor binding are unclear. Here, we have designed, chemically synthesized, and pharmacologically characterized more than 60 analogues of R3 B1-22R to develop an extensive understanding of its structure-activity relationships. We show that the key driver for affinity is the nonnative C-terminal Arg23 Additional contributors to binding include amino acid residues that are important also for relaxin-3 binding, including Arg12, Ile15, and Ile19 Intriguingly, amino acid residues that are not exposed in native relaxin-3, including Phe14 and Ala17, also interact with RXFP3. We show that R3 B1-22R has a propensity to form a helical structure, and modifications that support a helical conformation are functionally well-tolerated, whereas helix breakers such as proline residues disrupt binding. These data suggest that the peptide adopts a helical conformation, like relaxin-3, upon binding to RXFP3, but that its smaller size allows it to penetrate deeper into the orthosteric binding site, creating more extensive contacts with the receptor.
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Affiliation(s)
- Linda M Haugaard-Kedström
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia.,the Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark, and
| | - Han Siean Lee
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Maryon V Jones
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Angela Song
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Vishaal Rathod
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Ross A D Bathgate
- the Florey Institute of Neuroscience and Mental Health, .,Department of Biochemistry and Molecular Biology, University of Melbourne, Victoria 3010, Australia
| | - K Johan Rosengren
- From the Faculty of Medicine, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia,
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32
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Wilson KE, Limburg S, Duggan MK, Lawther AJ, Williams SJ, Lawrence AJ, Hale MW, Djouma E. The galanin receptor-3 antagonist, SNAP 37889, inhibits cue-induced reinstatement of alcohol-seeking and increases c-Fos expression in the nucleus accumbens shell of alcohol-preferring rats. J Psychopharmacol 2018; 32:911-921. [PMID: 29926762 DOI: 10.1177/0269881118780015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION This study aimed to investigate the effects of the galanin-3 receptor antagonist, SNAP 37889, on c-Fos protein expression after cue-induced reinstatement of alcohol-seeking in the brains of alcohol-preferring rats. METHODS Eighteen alcohol-preferring rats were trained to self-administer 10% v/v ethanol in the presence of response-contingent cues, which was followed by extinction. Rats were then treated with SNAP 37889 (30 mg/kg, i.p.) or vehicle, before being tested for cue-induced reinstatement. Administration of SNAP 37889 reduced cue-induced reinstatement of ethanol-seeking behaviour. To examine the effect of SNAP 37889 and cue-induced reinstatement on neuronal activation, c-Fos expression was measured in subregions of the medial prefrontal cortex and nucleus accumbens. RESULTS SNAP 37889 administration increased c-Fos immunoreactivity in the nucleus accumbens shell, but was without effect in the nucleus accumbens core and the medial prefrontal cortex. Dual-label Fos/tyrosine hydroxylase immunohistochemistry was used to examine the effects of SNAP 37889 on dopamine neurons in the ventral tegmental area; however, no differences between SNAP 37889 and vehicle-treated rats were found. CONCLUSIONS These data support previous findings of galanin-3 receptor involvement in cue-induced reinstatement of alcohol-seeking behaviour, and provide novel evidence that the ability of galanin-3 receptor antagonism to attenuate cue-induced reinstatement relates to activation of the nucleus accumbens shell.
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Affiliation(s)
- Kira-Elise Wilson
- 1 School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Sigrid Limburg
- 1 School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Melissa K Duggan
- 1 School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Adam J Lawther
- 1 School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Spencer J Williams
- 2 School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC, Australia
| | - Andrew J Lawrence
- 3 Florey Institute of Neuroscience and Mental Health, University of Melbourne, VIC, Australia
| | - Matthew W Hale
- 1 School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Elvan Djouma
- 4 School of Life Sciences, La Trobe University, Melbourne, VIC, Australia
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Berizzi AE, Perry CJ, Shackleford DM, Lindsley CW, Jones CK, Chen NA, Sexton PM, Christopoulos A, Langmead CJ, Lawrence AJ. Muscarinic M 5 receptors modulate ethanol seeking in rats. Neuropsychopharmacology 2018; 43:1510-1517. [PMID: 29483658 PMCID: PMC5983544 DOI: 10.1038/s41386-017-0007-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/26/2017] [Accepted: 12/29/2017] [Indexed: 12/16/2022]
Abstract
Despite the cost to both individual and society, alcohol use disorders (AUDs) remain a major health risk within society, and both relapse and heavy drinking are still poorly controlled with current medications. Here we demonstrate for the first time that a centrally active and selective negative allosteric modulator for the rat M5 muscarinic acetylcholine receptor (mAChR), ML375, decreases ethanol self-administration and attenuates cue-induced reinstatement of ethanol seeking in ethanol-preferring (iP) rats. Importantly, ML375 did not affect sucrose self-administration or general locomotor activity indicative of a selective effect on ethanol seeking. Based on the expression profile of M5 mAChRs in the brain and the distinct roles different aspects of the dorsal striatum have on long-term and short-term ethanol use, we studied whether intra-striatal microinjection of ML375 modulated ethanol intake in rats. We show in iP rats with an extensive history of ethanol intake that intra-dorsolateral (DL), but not intra-dorsomedial, striatal injections of ML375 reduced ethanol self-administration to a similar extent as the nicotinic acetylcholine receptor ligand varenicline, which has preclinical and clinical efficacy in reducing the reinforcing effects of ethanol. These data implicate the DL striatum as a locus for the effects of cholinergic-acting drugs on ethanol seeking in rats with a history of long-term ethanol use. Accordingly, we demonstrate in rats that selectively targeting the M5 mAChR can modulate both voluntary ethanol intake and cue-induced ethanol seeking and thereby provide direct evidence that the M5 mAChR is a potential novel target for pharmacotherapies aimed at treating AUDs.
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Affiliation(s)
- Alice E. Berizzi
- 0000 0004 1936 7857grid.1002.3Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052 Australia
| | - Christina J. Perry
- 0000 0004 0606 5526grid.418025.aThe Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3052 Australia
| | - David M. Shackleford
- 0000 0004 1936 7857grid.1002.3Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052 Australia
| | - Craig W. Lindsley
- 0000 0001 2264 7217grid.152326.1Departments of Pharmacology and Chemistry, Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232 USA
| | - Carrie K. Jones
- 0000 0001 2264 7217grid.152326.1Departments of Pharmacology and Chemistry, Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232 USA
| | - Nicola A. Chen
- 0000 0004 0606 5526grid.418025.aThe Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3052 Australia
| | - Patrick M. Sexton
- 0000 0004 1936 7857grid.1002.3Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052 Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.
| | - Christopher J. Langmead
- 0000 0004 1936 7857grid.1002.3Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052 Australia
| | - Andrew J. Lawrence
- 0000 0004 0606 5526grid.418025.aThe Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3052 Australia ,0000 0001 2179 088Xgrid.1008.9Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010 Australia
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Wang JH, Hu MJ, Shao XX, Wei D, Liu YL, Xu ZG, Guo ZY. Cholesterol modulates the binding properties of human relaxin family peptide receptor 3 with its ligands. Arch Biochem Biophys 2018; 646:24-30. [PMID: 29601823 DOI: 10.1016/j.abb.2018.03.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/10/2018] [Accepted: 03/26/2018] [Indexed: 12/14/2022]
Abstract
Relaxin family peptide receptor 3 (RXFP3) is implicated in the regulation of food intake and stress response upon activation by its cognate agonist relaxin-3. As an A-class G protein-coupled receptor, RXFP3 is an integral plasma membrane protein with seven transmembrane domains, yet influence of the membrane lipids on its function remains unknown. In the present study, we disclosed that cholesterol, an essential membrane lipid for mammalian cells, modulated the binding properties of human RXFP3 with its ligands. We first demonstrated that depletion of cholesterol from host human embryonic kidney (HEK) 293T cells by methyl-β-cyclodextrin altered ligand-binding properties of the overexpressed human RXFP3, such as increasing its binding potency with some antagonists and decreasing its binding affinity with a NanoLuc-conjugated R3/I5 tracer. Thereafter, we demonstrated that two B-chain residues, B5Tyr and B12Arg, were primarily responsible for the increased binding potency of these antagonists with human RXFP3 under the cholesterol depletion condition. Our results suggest that cell membrane cholesterol interacts with human RXFP3 and modulates its ligand-binding properties, providing new insights into the influence of membrane lipids on RXFP3 function.
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Affiliation(s)
- Jia-Hui Wang
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Meng-Jun Hu
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiao-Xia Shao
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Dian Wei
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ya-Li Liu
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zeng-Guang Xu
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhan-Yun Guo
- Research Centre for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China.
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Olucha-Bordonau FE, Albert-Gascó H, Ros-Bernal F, Rytova V, Ong-Pålsson EKE, Ma S, Sánchez-Pérez AM, Gundlach AL. Modulation of forebrain function by nucleus incertus and relaxin-3/RXFP3 signaling. CNS Neurosci Ther 2018; 24:694-702. [PMID: 29722152 DOI: 10.1111/cns.12862] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/22/2018] [Accepted: 03/28/2018] [Indexed: 01/05/2023] Open
Abstract
The nucleus incertus (NI) in the pontine tegmentum sends ascending projections to the midbrain, hypothalamus, amygdala, basal forebrain, hippocampus, and prefrontal cortex, and has a postulated role in modulating several forebrain functions. A substantial population of GABAergic NI neurons expresses the neuropeptide, relaxin-3, which acts via the Gi/o -protein-coupled receptor, RXFP3, present throughout the forebrain target regions. Broad and specific manipulations of these systems by activation or inhibition of the NI or modulating RXFP3 signaling have revealed key insights into the likely influence of the NI/relaxin-3/RXFP3 system on modalities including arousal, feeding, stress responses, anxiety and addiction, and attention and memory. This range of actions corresponds to a likely impact of NI/(relaxin-3) projections on multiple integrated circuits, but makes it difficult to draw conclusions about a generalized function for this network. This review will focus on the key physiological process of oscillatory theta rhythm and the neural circuits that promote it during behavioral activation, highlighting the ability of NI and relaxin-3/RXFP3 signaling systems to modulate these circuits. A better understanding of these mechanisms may provide a way to therapeutically adjust malfunction of forebrain activity present in several pathological conditions.
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Affiliation(s)
| | - Héctor Albert-Gascó
- Department of Medicine, School of Health Sciences, Universitat Jaume I, Castellón de la Plana, Spain
| | - Francisco Ros-Bernal
- Department of Medicine, School of Health Sciences, Universitat Jaume I, Castellón de la Plana, Spain
| | - Valeria Rytova
- The Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia
| | - Emma K E Ong-Pålsson
- The Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia
| | - Ana M Sánchez-Pérez
- Department of Medicine, School of Health Sciences, Universitat Jaume I, Castellón de la Plana, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia
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Abstract
Patients who suffer from alcohol use disorders (AUDs) usually go through various socio-behavioral and pathophysiological changes that take place in the brain and other organs. Recently, consumption of unhealthy food and excess alcohol along with a sedentary lifestyle has become a norm in both developed and developing countries. Despite the beneficial effects of moderate alcohol consumption, chronic and/or excessive alcohol intake is reported to negatively affect the brain, liver and other organs, resulting in cell death, organ damage/failure and death. The most effective therapy for alcoholism and alcohol related comorbidities is alcohol abstinence, however, chronic alcoholic patients cannot stop drinking alcohol. Therefore, targeted therapies are urgently needed to treat such populations. Patients who suffer from alcoholism and/or alcohol abuse experience harmful effects and changes that occur in the brain and other organs. Upon stopping alcohol consumption, alcoholic patients experience acute withdrawal symptoms followed by a protracted abstinence syndrome resulting in the risk of relapse to heavy drinking. For the past few decades, several drugs have been available for the treatment of AUDs. These drugs include medications to reduce or stop severe alcohol withdrawal symptoms during alcohol detoxification as well as recovery medications to reduce alcohol craving and support abstinence. However, there is no drug that completely antagonizes the adverse effects of excessive amounts of alcohol. This review summarizes the drugs which are available and approved by the FDA and their mechanisms of action as well as the medications that are under various phases of preclinical and clinical trials. In addition, the repurposing of the FDA approved drugs, such as anticonvulsants, antipsychotics, antidepressants and other medications, to prevent alcoholism and treat AUDs and their potential target mechanisms are summarized.
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Affiliation(s)
- Mohammed Akbar
- Division of Neuroscience and Behavior, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA.
| | - Mark Egli
- Division of Neuroscience and Behavior, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA
| | - Young-Eun Cho
- Section of Molecular Pharmacology and Toxicology, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA
| | - Byoung-Joon Song
- Section of Molecular Pharmacology and Toxicology, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA
| | - Antonio Noronha
- Division of Neuroscience and Behavior, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA
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Walker LC, Kastman HE, Koeleman JA, Smith CM, Perry CJ, Krstew EV, Gundlach AL, Lawrence AJ. Nucleus incertus corticotrophin-releasing factor 1 receptor signalling regulates alcohol seeking in rats. Addict Biol 2017; 22:1641-1654. [PMID: 27440230 DOI: 10.1111/adb.12426] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 01/01/2023]
Abstract
Alcoholism is a chronic relapsing disorder, and stress is a key precipitant of relapse. The nucleus incertus (NI) is highly responsive to corticotrophin-releasing factor (CRF) and psychological stressors, receives a CRF innervation and expresses CRF1 and CRF2 receptor mRNA. Furthermore, the ascending NI relaxin-3 system is implicated in alcohol seeking in rats. Therefore, in alcohol-preferring rats, we examined the effect of bilateral injections into the NI of the CRF1 receptor antagonist, CP376395 or the CRF2 receptor antagonist, astressin-2B on yohimbine-induced reinstatement of alcohol seeking. Using quantitative PCR analysis of NI micropunches, we assessed the effects of chronic alcohol consumption on gene expression profiles for components of the relaxin-3 and CRF systems. Bilateral intra-NI injections of CP376395 (500 ng/0.25 µl) attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injections of astressin-2B (200 ng/0.25 µl) had no significant effect. In line with these data, CRF1 , but not CRF2 , receptor mRNA was upregulated in the NI following chronic ethanol intake. Relaxin family peptide 3 receptor mRNA was also increased in the NI following chronic ethanol. Our quantitative PCR analysis also identified CRF mRNA within the rat NI, and the existence of a newly identified population of CRF-containing neurons was subsequently confirmed by detection of CRF immunoreactivity in rat and mouse NI. These data suggest that NI neurons contribute to reinstatement of alcohol seeking, via an involvement of CRF1 signalling. Furthermore, chronic ethanol intake leads to neuroadaptive changes in CRF and relaxin-3 systems within rat NI.
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Affiliation(s)
- Leigh C. Walker
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
| | - Hanna E. Kastman
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
| | - Jan A. Koeleman
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Institute for Interdisciplinary Studies; University of Amsterdam; Amsterdam 1098 XH the Netherlands
| | - Craig M. Smith
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
- School of Medicine; Deakin University; Geelong Victoria 3216 Australia
| | - Christina J. Perry
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
| | - Elena V. Krstew
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
| | - Andrew J. Lawrence
- The Florey Institute of Neuroscience and Mental Health; Parkville Victoria 3052 Australia
- Florey Department of Neuroscience and Mental Health; The University of Melbourne; Victoria 3010 Australia
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38
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Walker LC, Kastman HE, Krstew EV, Gundlach AL, Lawrence AJ. Central amygdala relaxin-3/relaxin family peptide receptor 3 signalling modulates alcohol seeking in rats. Br J Pharmacol 2017; 174:3359-3369. [PMID: 28726252 PMCID: PMC5595761 DOI: 10.1111/bph.13955] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/21/2017] [Accepted: 07/13/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Alcohol use disorders are a leading cause of preventable deaths worldwide, and stress is a major trigger of relapse. The neuropeptide relaxin-3 and its cognate receptor, relaxin family peptide receptor 3 (RXFP3), modulate stress-induced relapse to alcohol seeking in rats, and while the bed nucleus of the stria terminalis has been implicated in this regard, the central nucleus of the amygdala (CeA) also receives a relaxin-3 innervation and CeA neurons densely express RXFP3 mRNA. Moreover, the CeA is consistently implicated in both stress and addictive disorders. Yohimbine precipitates relapse-like behaviour in rodents, although exactly how yohimbine induces relapse is unknown, possibly by increasing stress levels and inducing heightened cue reactivity. EXPERIMENTAL APPROACH In the current study, we examined the effects of yohimbine (1 mg·kg-1 , i.p.) on anxiety-like behaviour in alcohol-experienced rats. Furthermore, we assessed CeA neuronal activation following yohimbine-induced reinstatement of alcohol seeking and the role of the relaxin-3/RXFP3 signalling within the CeA in yohimbine-induced reinstatement to alcohol seeking. KEY RESULTS Low-dose yohimbine was anxiogenic in rats with a history of alcohol use. Furthermore, yohimbine-induced reinstatement of alcohol seeking increased Fos activation in CeA corticotrophin-releasing factor, dynorphin and GABA neurons compared with naïve and vehicle controls. Bilateral intra-CeA injections of the selective RXFP3 antagonist, R3(B1-22)R, attenuated yohimbine-induced reinstatement of alcohol seeking. CONCLUSIONS Collectively, these data suggest that the CeA is a node where yohimbine acts to induce reinstatement of alcohol seeking and implicate the relaxin-3/RXFP3 system within the CeA in this process.
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Affiliation(s)
- Leigh C Walker
- The Florey Institute of Neuroscience and Mental HealthParkvilleVICAustralia
- Florey Department of Neuroscience and Mental HealthThe University of MelbourneParkvilleVICAustralia
| | - Hanna E Kastman
- The Florey Institute of Neuroscience and Mental HealthParkvilleVICAustralia
- Florey Department of Neuroscience and Mental HealthThe University of MelbourneParkvilleVICAustralia
| | - Elena V Krstew
- The Florey Institute of Neuroscience and Mental HealthParkvilleVICAustralia
- Florey Department of Neuroscience and Mental HealthThe University of MelbourneParkvilleVICAustralia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental HealthParkvilleVICAustralia
- Florey Department of Neuroscience and Mental HealthThe University of MelbourneParkvilleVICAustralia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental HealthParkvilleVICAustralia
- Florey Department of Neuroscience and Mental HealthThe University of MelbourneParkvilleVICAustralia
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Abstract
Addiction is a chronic relapsing disorder characterized by compulsive drug seeking and drug taking despite negative consequences. Alcohol abuse and addiction have major social and economic consequences and cause significant morbidity and mortality worldwide. Currently available therapeutics are inadequate, outlining the need for alternative treatments. Detailed knowledge of the neurocircuitry and brain chemistry responsible for aberrant behavior patterns should enable the development of novel pharmacotherapies to treat addiction. Therefore it is important to expand our knowledge and understanding of the neural pathways and mechanisms involved in alcohol seeking and abuse. The orexin (hypocretin) neuropeptide system is an attractive target, given the recent FDA and PMDA approval of suvorexant for the treatment of insomnia. Orexin is synthesized exclusively in neurons located in the lateral (LH), perifornical (PEF), and dorsal medial (DMH) hypothalamus. These neurons project widely throughout the neuraxis with regulatory roles in a wide range of behavioral and physiological responses, including sleep-wake cycle neuroendocrine regulation, anxiety, feeding behavior, and reward seeking. Here we summarize the literature to date, which have evaluated the interplay between alcohol and the orexin system.
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Affiliation(s)
- Leigh C Walker
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia.
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Zhang C, Baimoukhametova DV, Smith CM, Bains JS, Gundlach AL. Relaxin-3/RXFP3 signalling in mouse hypothalamus: no effect of RXFP3 activation on corticosterone, despite reduced presynaptic excitatory input onto paraventricular CRH neurons in vitro. Psychopharmacology (Berl) 2017; 234:1725-1739. [PMID: 28314951 DOI: 10.1007/s00213-017-4575-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 02/16/2017] [Indexed: 02/06/2023]
Abstract
Relaxin-3/RXFP3 signalling is proposed to be involved in the neuromodulatory control of arousal- and stress-related neural circuits. Furthermore, previous studies in rats have led to the proposal that relaxin-3/RXFP3 signalling is associated with activation of the hypothalamic-pituitary-adrenal axis, but direct evidence for RXFP3-related actions on the activity of hypothalamic corticotropin-releasing hormone (CRH) neurons is lacking. In this study, we investigated characteristics of the relaxin-3/RXFP3 system in mouse hypothalamus. Administration of an RXFP3 agonist (RXFP3-A2) intra-cerebroventricularly or directly into the paraventricular nucleus of hypothalamus (PVN) of C57BL/6J mice did not alter corticosterone levels. Similarly, there were no differences between serum corticosterone levels in Rxfp3 knockout (C57BL/6JRXFP3TM1) and wild-type mice at baseline and after stress, despite detection of the predicted stress-induced increases in serum corticosterone. We examined the nature of the relaxin-3 innervation of PVN in wild-type mice and in Crh-IRES-Cre;Ai14 mice that co-express the tdTomato fluorophore in CRH neurons, identifying abundant relaxin-3 fibres in the peri-PVN region, but only sparse fibres associated with densely packed CRH neurons. In whole-cell voltage-clamp recordings of tdTomato-positive CRH neurons in these mice, we observed a reduction in sEPSC frequency following local application of RXFP3-A2, consistent with an activation of RXFP3 on presynaptic glutamatergic afferents in the PVN region. These studies clarify the relationship between relaxin-3/RXFP3 inputs and CRH neurons in mouse PVN, with implications for the interpretation of current and previous in vivo studies and future investigations of this stress-related signalling network in normal and transgenic mice, under normal and pathological conditions.
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Affiliation(s)
- C Zhang
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - D V Baimoukhametova
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - C M Smith
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - J S Bains
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia. .,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia.
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Patil NA, Rosengren KJ, Separovic F, Wade JD, Bathgate RAD, Hossain MA. Relaxin family peptides: structure-activity relationship studies. Br J Pharmacol 2017; 174:950-961. [PMID: 27922185 DOI: 10.1111/bph.13684] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/25/2016] [Accepted: 11/28/2016] [Indexed: 12/21/2022] Open
Abstract
The human relaxin peptide family consists of seven cystine-rich peptides, four of which are known to signal through relaxin family peptide receptors, RXFP1-4. As these peptides play a vital role physiologically and in various diseases, they are of considerable importance for drug discovery and development. Detailed structure-activity relationship (SAR) studies towards understanding the role of important residues in each of these peptides have been reported over the years and utilized for the design of antagonists and minimized agonist variants. This review summarizes the current knowledge of the SAR of human relaxin 2 (H2 relaxin), human relaxin 3 (H3 relaxin), human insulin-like peptide 3 (INSL3) and human insulin-like peptide 5 (INSL5). LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Nitin A Patil
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,School of Chemistry, University of Melbourne, Parkville, VIC, Australia
| | - K Johan Rosengren
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
| | - Frances Separovic
- School of Chemistry, University of Melbourne, Parkville, VIC, Australia
| | - John D Wade
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,School of Chemistry, University of Melbourne, Parkville, VIC, Australia
| | - Ross A D Bathgate
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
| | - Mohammed Akhter Hossain
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,School of Chemistry, University of Melbourne, Parkville, VIC, Australia
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42
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Ma S, Smith CM, Blasiak A, Gundlach AL. Distribution, physiology and pharmacology of relaxin-3/RXFP3 systems in brain. Br J Pharmacol 2016; 174:1034-1048. [PMID: 27774604 DOI: 10.1111/bph.13659] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 01/29/2023] Open
Abstract
Relaxin-3 is a member of a superfamily of structurally-related peptides that includes relaxin and insulin-like peptide hormones. Soon after the discovery of the relaxin-3 gene, relaxin-3 was identified as an abundant neuropeptide in brain with a distinctive topographical distribution within a small number of GABAergic neuron populations that is well conserved across species. Relaxin-3 is thought to exert its biological actions through a single class-A GPCR - relaxin-family peptide receptor 3 (RXFP3). Class-A comprises GPCRs for relaxin-3 and insulin-like peptide-5 and other peptides such as orexin and the monoamine transmitters. The RXFP3 receptor is selectively activated by relaxin-3, whereas insulin-like peptide-5 is the cognate ligand for the related RXFP4 receptor. Anatomical and pharmacological evidence obtained over the last decade supports a function of relaxin-3/RXFP3 systems in modulating responses to stress, anxiety-related and motivated behaviours, circadian rhythms, and learning and memory. Electrophysiological studies have identified the ability of RXFP3 agonists to directly hyperpolarise thalamic neurons in vitro, but there are no reports of direct cell signalling effects in vivo. This article provides an overview of earlier studies and highlights more recent research that implicates relaxin-3/RXFP3 neural network signalling in the integration of arousal, motivation, emotion and related cognition, and that has begun to identify the associated neural substrates and mechanisms. Future research directions to better elucidate the connectivity and function of different relaxin-3 neuron populations and their RXFP3-positive target neurons in major experimental species and humans are also identified. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Craig M Smith
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia
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Stress differentially regulates brain expression of corticotropin-releasing factor in binge-like eating prone and resistant female rats. Appetite 2016; 107:585-595. [DOI: 10.1016/j.appet.2016.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 12/26/2022]
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Walker LC, Lawrence AJ. CRF and the nucleus incertus: a node for integration of stress signals. Nat Rev Neurosci 2016; 18:158. [DOI: 10.1038/nrn.2016.158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kumar JR, Rajkumar R, Jayakody T, Marwari S, Hong JM, Ma S, Gundlach AL, Lai MKP, Dawe GS. Relaxin' the brain: a case for targeting the nucleus incertus network and relaxin-3/RXFP3 system in neuropsychiatric disorders. Br J Pharmacol 2016; 174:1061-1076. [PMID: 27597467 PMCID: PMC5406295 DOI: 10.1111/bph.13564] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 07/15/2016] [Indexed: 12/14/2022] Open
Abstract
Relaxin‐3 has been proposed to modulate emotional–behavioural functions such as arousal and behavioural activation, appetite regulation, stress responses, anxiety, memory, sleep and circadian rhythm. The nucleus incertus (NI), in the midline tegmentum close to the fourth ventricle, projects widely throughout the brain and is the primary site of relaxin‐3 neurons. Over recent years, a number of preclinical studies have explored the function of the NI and relaxin‐3 signalling, including reports of mRNA or peptide expression changes in the NI in response to behavioural or pharmacological manipulations, effects of lesions or electrical or pharmacological manipulations of the NI, effects of central microinfusions of relaxin‐3 or related agonist or antagonist ligands on physiology and behaviour, and the impact of relaxin‐3 gene deletion or knockdown. Although these individual studies reveal facets of the likely functional relevance of the NI and relaxin‐3 systems for human physiology and behaviour, the differences observed in responses between species (e.g. rat vs. mouse), the clearly identified heterogeneity of NI neurons and procedural differences between laboratories are some of the factors that have prevented a precise understanding of their function. This review aims to draw attention to the current preclinical evidence available that suggests the relevance of the NI/relaxin‐3 system to the pathology and/or symptoms of certain neuropsychiatric disorders and to provide cognizant directions for future research to effectively and efficiently uncover its therapeutic potential. Linked Articles This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc
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Affiliation(s)
- Jigna Rajesh Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Tharindunee Jayakody
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Subhi Marwari
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Jia Mei Hong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
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Role of Lateral Hypothalamic Orexin (Hypocretin) Neurons in Alcohol Use and Abuse: Recent Advances. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s40495-016-0069-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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A negatively charged transmembrane aspartate residue controls activation of the relaxin-3 receptor RXFP3. Arch Biochem Biophys 2016; 604:113-20. [PMID: 27353281 DOI: 10.1016/j.abb.2016.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 01/18/2023]
Abstract
Relaxin-3 is an insulin/relaxin superfamily neuropeptide involved in the regulation of food intake and stress response via activation of its cognate receptor RXFP3, an A-class G protein-coupled receptor (GPCR). In recent studies, a highly conserved ExxxD motif essential for binding of relaxin-3 has been identified at extracellular end of the second transmembrane domain (TMD2) of RXFP3. For most of the A-class GPCRs, a highly conserved negatively charged Asp residue (Asp(2.50) using Ballesteros-Weinstein numbering and Asp128 in human RXFP3) is present at the middle of TMD2. To elucidate function of the conserved transmembrane Asp128, in the present work we replaced it with other residues and the resultant RXFP3 mutants all retained quite high ligand-binding potency, but their activation and agonist-induced internalization were abolished or drastically decreased. Thus, the negatively charged transmembrane Asp128 controlled transduction of agonist-binding information from the extracellular region to the intracellular region through maintaining RXFP3 in a metastable state for efficient conformational change induced by binding of an agonist.
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Calvez J, de Ávila C, Timofeeva E. Sex-specific effects of relaxin-3 on food intake and body weight gain. Br J Pharmacol 2016; 174:1049-1060. [PMID: 27245781 DOI: 10.1111/bph.13530] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 01/06/2023] Open
Abstract
Relaxin-3 (RLN3) is a neuropeptide that is strongly expressed in the pontine nucleus incertus (NI) and binds with high affinity to its cognate receptor RXFP3. Central administration of RLN3 in rats increases food intake and adiposity. In humans, RLN3 polymorphism has been associated with obesity and hypercholesterolaemia. Emerging evidence suggests that the effects of RLN3 may have sex-specific aspects. Thus, the RLN3 knockout female but not male mice are hypoactive. RLN3 produced stronger orexigenic and obesogenic effects in female rats compared with male rats. In addition, female rats demonstrated higher sensitivity to lower doses of RLN3. Repeated cycles of food restriction and stress were accompanied by an increase in RLN3 expression and hyperphagia in female but not in male rats. Furthermore, stress-induced binge eating in female rats was blocked by an RXFP3 receptor antagonist. RLN3 increased the expression of corticotropin releasing factor in the paraventricular hypothalamic nucleus in male but not in female rats. Conversely, in female rats, RLN3 increased the expression of orexin in the lateral hypothalamus. There is evidence that orexin directly activates the RLN3 neurons in the NI. The positive reinforcement of the RLN3 effects by orexin may intensify behavioural activation and feeding in females. Sex-specific effects of RLN3 may also depend on differential expression of RXFP3 receptors in the brain. Given the higher sensitivity of females to the orexigenic effects of RLN3 and the stress-induced activation of RLN3, the overall data suggest a possible role for RLN3 in eating disorders that show a higher propensity in women. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Juliane Calvez
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Camila de Ávila
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Elena Timofeeva
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
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Kastman HE, Blasiak A, Walker L, Siwiec M, Krstew EV, Gundlach AL, Lawrence AJ. Nucleus incertus Orexin2 receptors mediate alcohol seeking in rats. Neuropharmacology 2016; 110:82-91. [PMID: 27395787 DOI: 10.1016/j.neuropharm.2016.07.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/28/2016] [Accepted: 07/05/2016] [Indexed: 11/29/2022]
Abstract
Alcoholism is a chronic relapsing disorder and a major global health problem. Stress is a key precipitant of relapse in human alcoholics and in animal models of alcohol seeking. The brainstem nucleus incertus (NI) contains a population of relaxin-3 neurons that are highly responsive to psychological stressors; and the ascending NI relaxin-3/RXFP3 signalling system is implicated in stress-induced reinstatement of alcohol seeking. The NI receives orexinergic innervation and expresses orexin1 (OX1) and orexin2 (OX2) receptor mRNA. In alcohol-preferring (iP) rats, we examined the impact of yohimbine-induced reinstatement of alcohol seeking on orexin neuronal activation, and the effect of bilateral injections into NI of the OX1 receptor antagonist, SB-334867 (n = 16) or the OX2 receptor antagonist, TCS-OX2-29 (n = 8) on stress-induced reinstatement of alcohol seeking. We also assessed the effects of orexin-A on NI neuronal activity and the involvement of OX1 and OX2 receptors using whole cell patch-clamp recordings in rat brain slices. Yohimbine-induced reinstatement of alcohol seeking activated orexin neurons. Bilateral NI injections of TCS-OX2-29 attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injection of SB-334867 had no significant effect. In line with these data, orexin-A (600 nM) depolarized a majority of NI neurons recorded in coronal brain slices (18/28 cells), effects prevented by bath application of TCS-OX2-29 (10 μM), but not SB-334867 (10 μM). These data suggest an excitatory orexinergic input to NI contributes to yohimbine-induced reinstatement of alcohol seeking, predominantly via OX2 receptor signalling.
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Affiliation(s)
- Hanna E Kastman
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, 30-387 Krakow, Poland
| | - Leigh Walker
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Marcin Siwiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, 30-387 Krakow, Poland
| | - Elena V Krstew
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia.
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Identification of hydrophobic interactions between relaxin-3 and its receptor RXFP3: implication for a conformational change in the B-chain C-terminus during receptor binding. Amino Acids 2016; 48:2227-36. [PMID: 27193232 DOI: 10.1007/s00726-016-2260-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/11/2016] [Indexed: 01/05/2023]
Abstract
Relaxin-3 is an insulin/relaxin superfamily neuropeptide implicated in the regulation of food intake and stress response via activation of the G protein-coupled receptor RXFP3. Their electrostatic interactions have been recently identified, and involves three positively charged B-chain residues (B12Arg, B16Arg, and B26Arg) of relaxin-3 and two negatively charged residues (Glu141 and Asp145) in a highly conserved ExxxD motif at the extracellular end of the second transmembrane domain of RXFP3. To investigate their hydrophobic interactions, in the present work we deleted the highly conserved B-chain C-terminal B27Trp residue of relaxin-3, and mutated four highly conserved aromatic residues (Phe137, Trp138, Phe146, and Trp148) around the ExxxD motif of RXFP3. The resultant [∆B27W]relaxin-3 exhibited approximately tenfold lower binding potency and ~1000-fold lower activation potency towards wild-type RXFP3, confirming its importance for relaxin-3 function. Although the RXFP3 mutants could be normally trafficked to cell membrane, they had quite different activities. [F137A]RXFP3 could normally distinguish wild-type relaxin-3 and [∆B27W]relaxin-3 in binding and activation assays, whereas [W138A]RXFP3 lost most of this capability, suggesting that the Trp138 residue of RXFP3 forms hydrophobic interactions with the B27Trp residue of relaxin-3. The hydrophobic Trp138 residue and the formerly identified negatively charged Glu141 and Asp145 residues in the highly conserved WxxExxxD motif may thus form a functional surface that is important for interaction with relaxin-3. We hypothesize that the relaxin-3 B-chain C-terminus changes from the original folding-back conformation to an extended conformation during binding with RXFP3, to allow its B27Trp and B26Arg residues to interact with the Trp138 and Glu141 residues of RXFP3, respectively.
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