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Vafaei Z, Khodagholi F, Nategh M, Nikseresht S, Hashemirad SR, Raise-Abdullahi P, Vafaei AA, Motamedi F. Involvement of relaxin-family peptide-3 receptor (RXFP3) in the ventral dentate gyrus of the hippocampus in spatial and fear memory in rats. Peptides 2024; 178:171244. [PMID: 38788901 DOI: 10.1016/j.peptides.2024.171244] [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: 12/26/2023] [Revised: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
The neuropeptide relaxin-3 and its cognate receptor, relaxin family peptide-3 receptors (RXFP3), have been implicated in modulating learning and memory processes, but their specific roles remain unclear. This study utilized behavioral and molecular approaches to investigate the effects of putatively reversible blockade of RXFP3 in the ventral dentate gyrus (vDG) of the hippocampus on spatial and fear memory formation in rats. Male Wistar rats received bilateral vDG cannula implantation and injections of the RXFP3 antagonist, R3(BΔ23-27)R/I5 (400 ng/0.5 μL per side), or vehicle at specific time points before acquisition, consolidation, or retrieval phases of the Morris water maze and passive avoidance learning tasks. RXFP3 inhibition impaired acquisition in the passive avoidance task but not the spatial learning task. However, both memory consolidation and retrieval were disrupted in both tasks following RXFP3 antagonism. Ventral hippocampal levels of the consolidation-related kinase p70-S6 kinase (p70S6K) were reduced RXFP3 blockade. These findings highlight a key role for ventral hippocampal RXFP3 signaling in the acquisition, consolidation, and retrieval of spatial and emotional memories, extending previous work implicating this neuropeptide system in hippocampal memory processing.
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Affiliation(s)
- Zohreh Vafaei
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fariba Khodagholi
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Nategh
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Sara Nikseresht
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Pharmacology and Therapeutics, the University of Melbourne, Parkville, Victoria, Australia
| | - Seyed Reza Hashemirad
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Abbas Ali Vafaei
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran.
| | - Fereshteh Motamedi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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de Ávila C, Gugula A, Trenk A, Intorcia AJ, Suazo C, Nolz J, Plamondon J, Khatri D, Tallant L, Caron A, Blasiak A, Serrano GE, Beach TG, Gundlach AL, Mastroeni DF. Unveiling a novel memory center in human brain: neurochemical identification of the nucleus incertus, a key pontine locus implicated in stress and neuropathology. Biol Res 2024; 57:46. [PMID: 39014514 PMCID: PMC11253401 DOI: 10.1186/s40659-024-00523-z] [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: 10/13/2023] [Accepted: 06/07/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND The nucleus incertus (NI) was originally described by Streeter in 1903, as a midline region in the floor of the fourth ventricle of the human brain with an 'unknown' function. More than a century later, the neuroanatomy of the NI has been described in lower vertebrates, but not in humans. Therefore, we examined the neurochemical anatomy of the human NI using markers, including the neuropeptide, relaxin-3 (RLN3), and began to explore the distribution of the NI-related RLN3 innervation of the hippocampus. METHODS Histochemical staining of serial, coronal sections of control human postmortem pons was conducted to reveal the presence of the NI by detection of immunoreactivity (IR) for the neuronal markers, microtubule-associated protein-2 (MAP2), glutamic acid dehydrogenase (GAD)-65/67 and corticotrophin-releasing hormone receptor 1 (CRHR1), and RLN3, which is highly expressed in NI neurons in diverse species. RLN3 and vesicular GABA transporter 1 (vGAT1) mRNA were detected by fluorescent in situ hybridization. Pons sections containing the NI from an AD case were immunostained for phosphorylated-tau, to explore potential relevance to neurodegenerative diseases. Lastly, sections of the human hippocampus were stained to detect RLN3-IR and somatostatin (SST)-IR. RESULTS In the dorsal, anterior-medial region of the human pons, neurons containing RLN3- and MAP2-IR, and RLN3/vGAT1 mRNA-positive neurons were observed in an anatomical pattern consistent with that of the NI in other species. GAD65/67- and CRHR1-immunopositive neurons were also detected within this area. Furthermore, RLN3- and AT8-IR were co-localized within NI neurons of an AD subject. Lastly, RLN3-IR was detected in neurons within the CA1, CA2, CA3 and DG areas of the hippocampus, in the absence of RLN3 mRNA. In the DG, RLN3- and SST-IR were co-localized in a small population of neurons. CONCLUSIONS Aspects of the anatomy of the human NI are shared across species, including a population of stress-responsive, RLN3-expressing neurons and a RLN3 innervation of the hippocampus. Accumulation of phosphorylated-tau in the NI suggests its possible involvement in AD pathology. Further characterization of the neurochemistry of the human NI will increase our understanding of its functional role in health and disease.
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Affiliation(s)
- Camila de Ávila
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA.
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Anthony J Intorcia
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Crystal Suazo
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | - Jennifer Nolz
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | | | - Divyanshi Khatri
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | - Lauren Tallant
- Department of Neuroscience, Mayo Clinic, Scottsdale, AZ, USA
| | - Alexandre Caron
- Quebec Heart and Lung Institute, Quebec City, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Geidy E Serrano
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Thomas G Beach
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Andrew L Gundlach
- Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology and The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Diego F Mastroeni
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
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Navarro-Sánchez M, Gil-Miravet I, Montero-Caballero D, Bathgate RAD, Hossain MA, Castillo-Gómez E, Gundlach AL, Olucha-Bordonau FE. Modulation of contextual fear acquisition and extinction by acute and chronic relaxin-3 receptor (RXFP3) activation in the rat retrosplenial cortex. Biochem Pharmacol 2024; 225:116264. [PMID: 38710334 DOI: 10.1016/j.bcp.2024.116264] [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: 01/16/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
The retrosplenial cortex (RSC) plays a central role in processing contextual fear conditioning. In addition to corticocortical and thalamocortical projections, the RSC receives subcortical inputs, including a substantial projection from the nucleus incertus in the pontine tegmentum. This GABAergic projection contains the neuropeptide, relaxin-3 (RLN3), which inhibits target neurons via its Gi/o-protein-coupled receptor, RXFP3. To assess this peptidergic system role in contextual fear conditioning, we bilaterally injected the RSC of adult rats with an adeno-associated-virus (AAV), expressing the chimeric RXFP3 agonist R3/I5 or a control AAV, and subjected them to contextual fear conditioning. The R3/I5 injected rats did not display any major differences to control-injected and naïve rats but displayed a significantly delayed extinction. Subsequently, we employed acute bilateral injections of the specific RXFP3 agonist peptide, RXFP3-Analogue 2 (A2), into RSC. While the administration of A2 before each extinction trial had no impact on the extinction process, treatment with A2 before each acquisition trial resulted in delayed extinction. In related anatomical studies, we detected an enrichment of RLN3-immunoreactive nerve fibers in deep layers of the RSC, and a higher level of co-localization of RXFP3 mRNA with vesicular GABA transporter (vGAT) mRNA than with vesicular glutamate transporter-1 (vGLUT1) mRNA across the RSC, consistent with an effect of RLN3/RXFP3 signalling on the intrinsic, inhibitory circuits within the RSC. These findings suggest that contextual conditioning processes in the RSC involve, in part, RLN3 afferent modulation of local inhibitory neurons that provides a stronger memory acquisition which, in turn, retards the extinction process.
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Affiliation(s)
- Mónica Navarro-Sánchez
- Departamento de Medicina, Facultad de Ciencias de La Salud, Universitat Jaume I, Castellón, Spain
| | - Isis Gil-Miravet
- Departamento de Medicina, Facultad de Ciencias de La Salud, Universitat Jaume I, Castellón, Spain
| | - Daniel Montero-Caballero
- Departamento de Medicina, Facultad de Ciencias de La Salud, Universitat Jaume I, Castellón, Spain
| | - Ross A D Bathgate
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Department of Biochemistry and Pharmacology, The University of Melbourne, Victoria, Australia
| | - Mohammed Akhter Hossain
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Esther Castillo-Gómez
- Departamento de Medicina, Facultad de Ciencias de La Salud, Universitat Jaume I, Castellón, Spain; CIBERsam-isciii, Red Española de Estrés, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Francisco E Olucha-Bordonau
- Departamento de Medicina, Facultad de Ciencias de La Salud, Universitat Jaume I, Castellón, Spain; CIBERsam-isciii, Red Española de Estrés, Spain.
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4
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Spikol ED, Cheng J, Macurak M, Subedi A, Halpern ME. Genetically defined nucleus incertus neurons differ in connectivity and function. eLife 2024; 12:RP89516. [PMID: 38819436 PMCID: PMC11142643 DOI: 10.7554/elife.89516] [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] [Indexed: 06/01/2024] Open
Abstract
The nucleus incertus (NI), a conserved hindbrain structure implicated in the stress response, arousal, and memory, is a major site for production of the neuropeptide relaxin-3. On the basis of goosecoid homeobox 2 (gsc2) expression, we identified a neuronal cluster that lies adjacent to relaxin 3a (rln3a) neurons in the zebrafish analogue of the NI. To delineate the characteristics of the gsc2 and rln3a NI neurons, we used CRISPR/Cas9 targeted integration to drive gene expression specifically in each neuronal group, and found that they differ in their efferent and afferent connectivity, spontaneous activity, and functional properties. gsc2 and rln3a NI neurons have widely divergent projection patterns and innervate distinct subregions of the midbrain interpeduncular nucleus (IPN). Whereas gsc2 neurons are activated more robustly by electric shock, rln3a neurons exhibit spontaneous fluctuations in calcium signaling and regulate locomotor activity. Our findings define heterogeneous neurons in the NI and provide new tools to probe its diverse functions.
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Affiliation(s)
- Emma D Spikol
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ji Cheng
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Michelle Macurak
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Abhignya Subedi
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Marnie E Halpern
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
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Jayakody T, Inoue A, Kannan S, Nakamura G, Kawakami K, Mendis K, Nguyen TB, Li J, Herr DR, Verma CS, Dawe GS. Mechanisms of biased agonism by Gα i/o-biased stapled peptide agonists of the relaxin-3 receptor. Sci Signal 2024; 17:eabl5880. [PMID: 38349968 DOI: 10.1126/scisignal.abl5880] [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: 07/22/2021] [Accepted: 01/26/2024] [Indexed: 02/15/2024]
Abstract
The neuropeptide relaxin-3 is composed of an A chain and a B chain held together by disulfide bonds, and it modulates functions such as anxiety and food intake by binding to and activating its cognate receptor RXFP3, mainly through the B chain. Biased ligands of RXFP3 would help to determine the molecular mechanisms underlying the activation of G proteins and β-arrestins downstream of RXFP3 that lead to such diverse functions. We showed that the i, i+4 stapled relaxin-3 B chains, 14s18 and d(1-7)14s18, were Gαi/o-biased agonists of RXFP3. These peptides did not induce recruitment of β-arrestin1/2 to RXFP3 by GPCR kinases (GRKs), in contrast to relaxin-3, which enabled the GRK2/3-mediated recruitment of β-arrestin1/2 to RXFP3. Relaxin-3 and the previously reported peptide 4 (an i, i+4 stapled relaxin-3 B chain) did not exhibit biased signaling. The staple linker of peptide 4 and parts of both the A chain and B chain of relaxin-3 interacted with extracellular loop 3 (ECL3) of RXFP3, moving it away from the binding pocket, suggesting that unbiased ligands promote a more open conformation of RXFP3. These findings highlight roles for the A chain and the N-terminal residues of the B chain of relaxin-3 in inducing conformational changes in RXFP3, which will help in designing selective biased ligands with improved therapeutic efficacy.
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Affiliation(s)
- Tharindunee Jayakody
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore
- Department of Chemistry, University of Colombo, P.O. Box 1490, Colombo 00300, Sri Lanka
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | | | - Gaku Nakamura
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Krishan Mendis
- Department of Chemistry, University of Colombo, P.O. Box 1490, Colombo 00300, Sri Lanka
| | - Thanh-Binh Nguyen
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Jianguo Li
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Deron R Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Chandra S Verma
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671
- Department of Biological Sciences, National University of Singapore, 6 Science Drive 4, Singapore 117558
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr., Singapore 637551
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Precision Medicine Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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6
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Jung J, Han H. The diverse influences of relaxin-like peptide family on tumor progression: Potential opportunities and emerging challenges. Heliyon 2024; 10:e24463. [PMID: 38298643 PMCID: PMC10828710 DOI: 10.1016/j.heliyon.2024.e24463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
Relaxin-like peptide family exhibit differential expression patterns in various types of cancers and play a role in cancer development. This family participates in tumorigenic processes encompassing proliferation, migration, invasion, tumor microenvironment, immune microenvironment, and anti-cancer resistance, ultimately influencing patient prognosis. In this review, we explore the mechanisms underlying the interaction between the RLN-like peptide family and tumors and provide an overview of therapeutic approaches utilizing this interaction.
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Affiliation(s)
| | - Hyunho Han
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
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7
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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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8
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Király B, Domonkos A, Jelitai M, Lopes-Dos-Santos V, Martínez-Bellver S, Kocsis B, Schlingloff D, Joshi A, Salib M, Fiáth R, Barthó P, Ulbert I, Freund TF, Viney TJ, Dupret D, Varga V, Hangya B. The medial septum controls hippocampal supra-theta oscillations. Nat Commun 2023; 14:6159. [PMID: 37816713 PMCID: PMC10564782 DOI: 10.1038/s41467-023-41746-0] [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: 07/27/2022] [Accepted: 09/15/2023] [Indexed: 10/12/2023] Open
Abstract
Hippocampal theta oscillations orchestrate faster beta-to-gamma oscillations facilitating the segmentation of neural representations during navigation and episodic memory. Supra-theta rhythms of hippocampal CA1 are coordinated by local interactions as well as inputs from the entorhinal cortex (EC) and CA3 inputs. However, theta-nested gamma-band activity in the medial septum (MS) suggests that the MS may control supra-theta CA1 oscillations. To address this, we performed multi-electrode recordings of MS and CA1 activity in rodents and found that MS neuron firing showed strong phase-coupling to theta-nested supra-theta episodes and predicted changes in CA1 beta-to-gamma oscillations on a cycle-by-cycle basis. Unique coupling patterns of anatomically defined MS cell types suggested that indirect MS-to-CA1 pathways via the EC and CA3 mediate distinct CA1 gamma-band oscillations. Optogenetic activation of MS parvalbumin-expressing neurons elicited theta-nested beta-to-gamma oscillations in CA1. Thus, the MS orchestrates hippocampal network activity at multiple temporal scales to mediate memory encoding and retrieval.
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Affiliation(s)
- Bálint Király
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Biological Physics, Institute of Physics, Eötvös Loránd University, Budapest, Hungary
| | - Andor Domonkos
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Márta Jelitai
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Vítor Lopes-Dos-Santos
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Sergio Martínez-Bellver
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Anatomy and Human Embryology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain
| | - Barnabás Kocsis
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Dániel Schlingloff
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Minas Salib
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Richárd Fiáth
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Péter Barthó
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - István Ulbert
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Tamás F Freund
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Tim J Viney
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - David Dupret
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Viktor Varga
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.
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9
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Gil-Miravet I, Núñez-Molina Á, Navarro-Sánchez M, Castillo-Gómez E, Ros-Bernal F, Gundlach AL, Olucha-Bordonau FE. Nucleus incertus projections to rat medial septum and entorhinal cortex: rare collateralization and septal-gating of temporal lobe theta rhythm activity. Brain Struct Funct 2023:10.1007/s00429-023-02650-x. [PMID: 37173580 DOI: 10.1007/s00429-023-02650-x] [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: 12/24/2022] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
Nucleus incertus (NI) neurons in the pontine tegmentum give rise to ascending forebrain projections and express the neuropeptide relaxin-3 (RLN3) which acts via the relaxin-family peptide 3 receptor (RXFP3). Activity in the hippocampus and entorhinal cortex can be driven from the medial septum (MS), and the NI projects to all these centers, where a prominent pattern of activity is theta rhythm, which is related to spatial memory processing. Therefore, we examined the degree of collateralization of NI projections to the MS and the medial temporal lobe (MTL), comprising medial and lateral entorhinal cortex (MEnt, LEnt) and dentate gyrus (DG), and the ability of the MS to drive entorhinal theta in the adult rat. We injected fluorogold and cholera toxin-B into the MS septum and either MEnt, LEnt or DG, to determine the percentage of retrogradely labeled neurons in the NI projecting to both or single targets, and the relative proportion of these neurons that were RLN3-positive ( +). The projection to the MS was threefold stronger than that to the MTL. Moreover, a majority of NI neurons projected independently to either MS or the MTL. However, RLN3 + neurons collateralize significantly more than RLN3-negative (-) neurons. In in vivo studies, electrical stimulation of the NI induced theta activity in the MS and the entorhinal cortex, which was impaired by intraseptal infusion of an RXFP3 antagonist, R3(BΔ23-27)R/I5, particularly at ~ 20 min post-injection. These findings suggest that the MS plays an important relay function in the NI-induced generation of theta within the entorhinal cortex.
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Grants
- POSDOC/2021/19 Universitat Jaume I
- PREDOC/2021/19 Universitat Jaume I
- UJI-A2017-17 Universitat Jaume I
- POSDOC/2021/19 Universitat Jaume I
- PID2019-107809RB-I00 Ministerio de Ciencia, Innovación y Universidades
- RTI2018-095698-B-I00 Ministerio de Ciencia, Innovación y Universidades
- RTI2018-095698-B-I00 Ministerio de Ciencia, Innovación y Universidades
- RTI2018-095698-B-I00 Ministerio de Ciencia, Innovación y Universidades
- 19I436 Fundación Alicia Koplowitz
- 19I436 Fundación Alicia Koplowitz
- 19I436 Fundación Alicia Koplowitz
- AICO/2021/246 Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital, Generalitat Valenciana
- AICO/2021/246 Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital, Generalitat Valenciana
- AICO/2021/246 Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital, Generalitat Valenciana
- 1067522 National Health and Medical Research Council
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Affiliation(s)
- Isis Gil-Miravet
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, CIBERSAM-ISCIII, S/N 12071, Castellón de la Plana, Spain
| | - Ángel Núñez-Molina
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mónica Navarro-Sánchez
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, CIBERSAM-ISCIII, S/N 12071, Castellón de la Plana, Spain
| | - Esther Castillo-Gómez
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, CIBERSAM-ISCIII, S/N 12071, Castellón de la Plana, Spain
| | - Francisco Ros-Bernal
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, CIBERSAM-ISCIII, S/N 12071, Castellón de la Plana, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Francisco E Olucha-Bordonau
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, CIBERSAM-ISCIII, S/N 12071, Castellón de la Plana, Spain.
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10
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Ros-Bernal F, Gil-Miravet I, Lucerón J, Navarro-Sánchez M, Castillo-Gómez E, Gundlach AL, Olucha-Bordonau FE. Postnatal development of the relaxin-3 innervation of the rat medial septum. Front Neurosci 2023; 17:1176587. [PMID: 37234259 PMCID: PMC10206071 DOI: 10.3389/fnins.2023.1176587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/17/2023] [Indexed: 05/27/2023] Open
Abstract
Introduction The septal area provides a rich innervation to the hippocampus regulating hippocampal excitability to different behavioral states and modulating theta rhythmogenesis. However, little is known about the neurodevelopmental consequences of its alterations during postnatal development. The activity of the septohippocampal system is driven and/or modulated by ascending inputs, including those arising from the nucleus incertus (NI), many of which contain the neuropeptide, relaxin-3 (RLN3). Methods We examined at the molecular and cellular level the ontogeny of RLN3 innervation of the septal area in postnatal rat brains. Results Up until P13-15 there were only scattered fibers in the septal area, but a dense plexus had appeared by P17 that was extended and consolidated throughout the septal complex by P20. There was a decrease in the level of colocalization of RLN3 and synaptophysin between P15 and P20 that was reversed between P20 and adulthood. Biotinylated 3-kD dextran amine injections into the septum, revealed retrograde labeling present in the brainstem at P10-P13, but a decrease in anterograde fibers in the NI between P10-20. Simultaneously, a differentiation process began during P10-17, resulting in fewer NI neurons double-labeled for serotonin and RLN3. Discussion The onset of the RLN3 innervation of the septum complex between P17-20 is correlated with the onset of hippocampal theta rhythm and several learning processes associated with hippocampal function. Together, these data highlight the relevance and need for further analysis of this stage for normal and pathological septohippocampal development.
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Affiliation(s)
- Francisco Ros-Bernal
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
| | - Isis Gil-Miravet
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
| | - Jorge Lucerón
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
| | - Mónica Navarro-Sánchez
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
| | - Esther Castillo-Gómez
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
- Centro de Investigación Biomédica en Red de Salud Mental, (CIBERSAM), Madrid, Spain
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Francisco E. Olucha-Bordonau
- Unitat Predepartamental de Medicina, Facultad de Ciencias de la Slud, Universitat Jaume I, Castellón, Spain
- Centro de Investigación Biomédica en Red de Salud Mental, (CIBERSAM), Madrid, Spain
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11
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Huygens synchronization of medial septal pacemaker neurons generates hippocampal theta oscillation. Cell Rep 2022; 40:111149. [PMID: 35926456 DOI: 10.1016/j.celrep.2022.111149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/06/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022] Open
Abstract
Episodic learning and memory retrieval are dependent on hippocampal theta oscillation, thought to rely on the GABAergic network of the medial septum (MS). To test how this network achieves theta synchrony, we recorded MS neurons and hippocampal local field potential simultaneously in anesthetized and awake mice and rats. We show that MS pacemakers synchronize their individual rhythmicity frequencies, akin to coupled pendulum clocks as observed by Huygens. We optogenetically identified them as parvalbumin-expressing GABAergic neurons, while MS glutamatergic neurons provide tonic excitation sufficient to induce theta. In accordance, waxing and waning tonic excitation is sufficient to toggle between theta and non-theta states in a network model of single-compartment inhibitory pacemaker neurons. These results provide experimental and theoretical support to a frequency-synchronization mechanism for pacing hippocampal theta, which may serve as an inspirational prototype for synchronization processes in the central nervous system from Nematoda to Arthropoda to Chordate and Vertebrate phyla.
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12
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Papazoglou A, Arshaad MI, Henseler C, Daubner J, Broich K, Hescheler J, Ehninger D, Haenisch B, Weiergräber M. Ca v3 T-Type Voltage-Gated Ca 2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance. Int J Mol Sci 2022; 23:ijms23073457. [PMID: 35408817 PMCID: PMC8998330 DOI: 10.3390/ijms23073457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/07/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer’s disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aβ levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly.
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Affiliation(s)
- Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Muhammad Imran Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
| | - Jürgen Hescheler
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Dan Ehninger
- Translational Biogerontology, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany;
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
| | - Britta Haenisch
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
- Center for Translational Medicine, Medical Faculty, University of Bonn, 53113 Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
- Correspondence: ; Tel.: +49-228-99307-4358
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13
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Szlaga A, Sambak P, Trenk A, Gugula A, Singleton CE, Drwiega G, Blasiak T, Ma S, Gundlach AL, Blasiak A. Functional Neuroanatomy of the Rat Nucleus Incertus–Medial Septum Tract: Implications for the Cell-Specific Control of the Septohippocampal Pathway. Front Cell Neurosci 2022; 16:836116. [PMID: 35281300 PMCID: PMC8913896 DOI: 10.3389/fncel.2022.836116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
The medial septum (MS) is critically involved in theta rhythmogenesis and control of the hippocampal network, with which it is reciprocally connected. MS activity is influenced by brainstem structures, including the stress-sensitive, nucleus incertus (NI), the main source of the neuropeptide relaxin-3 (RLN3). In the current study, we conducted a comprehensive neurochemical and electrophysiological characterization of NI neurons innervating the MS in the rat, by employing classical and viral-based neural tract-tracing and electrophysiological approaches, and multiplex fluorescent in situ hybridization. We confirmed earlier reports that the MS is innervated by RLN3 NI neurons and documented putative glutamatergic (vGlut2 mRNA-expressing) neurons as a relevant NI neuronal population within the NI–MS tract. Moreover, we observed that NI neurons innervating MS can display a dual phenotype for GABAergic and glutamatergic neurotransmission, and that 40% of MS-projecting NI neurons express the corticotropin-releasing hormone-1 receptor. We demonstrated that an identified cholecystokinin (CCK)-positive NI neuronal population is part of the NI–MS tract, and that RLN3 and CCK NI neurons belong to a neuronal pool expressing the calcium-binding proteins, calbindin and calretinin. Finally, our electrophysiological studies revealed that MS is innervated by A-type potassium current-expressing, type I NI neurons, and that type I and II NI neurons differ markedly in their neurophysiological properties. Together these findings indicate that the MS is controlled by a discrete NI neuronal network with specific electrophysiological and neurochemical features; and these data are of particular importance for understanding neuronal mechanisms underlying the control of the septohippocampal system and related behaviors.
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Affiliation(s)
- Agata Szlaga
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Patryk Sambak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Caitlin E. Singleton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Gniewosz Drwiega
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Tomasz Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
- *Correspondence: Anna Blasiak,
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14
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Changes in microRNA expression profiles in diabetic cardiomyopathy rats following H3 relaxin treatment. J Cardiovasc Pharmacol 2021; 79:530-538. [PMID: 34983906 DOI: 10.1097/fjc.0000000000001211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 12/06/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT MicroRNAs (miRNAs) are noncoding RNAs that play an important role in the mechanisms of diabetic cardiomyopathy (DCM); however, whether human recombinant relaxin-3 (H3 relaxin) inhibits myocardial injury in DCM rats and the underlying mechanisms involving miRNAs remain unknown. miRNA expression profiles were detected using miRNA microarray and bioinformatics analyses of myocardial tissues from control, DCM, and H3 relaxin-administered DCM groups, and the regulatory mechanisms of the miRNAs were investigated. A total of five miRNAs were downregulated in the myocardial tissues of DCM rats and upregulated in H3 relaxin-treated DCM rats, and one miRNA (miRNA let-7d-3p) was increased in the myocardial tissue of DCM rats, and decreased in H3 relaxin-treated DCM rats as revealed by miRNA microarray and validated by real-time PCR. Important signaling pathways were found to be triggered by the differentially expressed miRNAs, including metabolism, cancer, Rap1, PI3K-Akt, and MAPK signaling pathways. The study revealed that H3 relaxin improved glucose uptake in DCM rats, potentially via regulation of miRNA let-7d-3p.
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15
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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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16
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Takeuchi Y, Nagy AJ, Barcsai L, Li Q, Ohsawa M, Mizuseki K, Berényi A. The Medial Septum as a Potential Target for Treating Brain Disorders Associated With Oscillopathies. Front Neural Circuits 2021; 15:701080. [PMID: 34305537 PMCID: PMC8297467 DOI: 10.3389/fncir.2021.701080] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/14/2021] [Indexed: 12/14/2022] Open
Abstract
The medial septum (MS), as part of the basal forebrain, supports many physiological functions, from sensorimotor integration to cognition. With often reciprocal connections with a broad set of peers at all major divisions of the brain, the MS orchestrates oscillatory neuronal activities throughout the brain. These oscillations are critical in generating sensory and emotional salience, locomotion, maintaining mood, supporting innate anxiety, and governing learning and memory. Accumulating evidence points out that the physiological oscillations under septal influence are frequently disrupted or altered in pathological conditions. Therefore, the MS may be a potential target for treating neurological and psychiatric disorders with abnormal oscillations (oscillopathies) to restore healthy patterns or erase undesired ones. Recent studies have revealed that the patterned stimulation of the MS alleviates symptoms of epilepsy. We discuss here that stimulus timing is a critical determinant of treatment efficacy on multiple time scales. On-demand stimulation may dramatically reduce side effects by not interfering with normal physiological functions. A precise pattern-matched stimulation through adaptive timing governed by the ongoing oscillations is essential to effectively terminate pathological oscillations. The time-targeted strategy for the MS stimulation may provide an effective way of treating multiple disorders including Alzheimer's disease, anxiety/fear, schizophrenia, and depression, as well as pain.
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Affiliation(s)
- Yuichi Takeuchi
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Anett J. Nagy
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Lívia Barcsai
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Qun Li
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Masahiro Ohsawa
- Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Antal Berényi
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
- Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary
- HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged, Hungary
- Neuroscience Institute, New York University, New York, NY, United States
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17
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García-Díaz C, Gil-Miravet I, Albert-Gasco H, Mañas-Ojeda A, Ros-Bernal F, Castillo-Gómez E, Gundlach AL, Olucha-Bordonau FE. Relaxin-3 Innervation From the Nucleus Incertus to the Parahippocampal Cortex of the Rat. Front Neuroanat 2021; 15:674649. [PMID: 34239421 PMCID: PMC8258164 DOI: 10.3389/fnana.2021.674649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
Spatial learning and memory processes depend on anatomical and functional interactions between the hippocampus and the entorhinal cortex. A key neurophysiological component of these processes is hippocampal theta rhythm, which can be driven from subcortical areas including the pontine nucleus incertus (NI). The NI contains the largest population of neurons that produce and presumably release the neuropeptide, relaxin-3, which acts via the G i/o -protein-coupled receptor, relaxin-family peptide 3 receptor (RXFP3). NI activation induces general arousal including hippocampal theta, and inactivation induces impairment of spatial memory acquisition or retrieval. The primary aim of this study was to map the NI/relaxin-3 innervation of the parahippocampal cortex (PHC), including the medial and lateral entorhinal cortex, endopiriform cortex, perirhinal, postrhinal, and ectorhinal cortex, the amygdalohippocampal transition area and posteromedial cortical amygdala. Retrograde tracer injections were placed in different parts of the medial and lateral entorhinal cortex, which produced prominent retrograde labeling in the ipsilateral NI and some labeling in the contralateral NI. Anterograde tracer injections into the NI and immunostaining for relaxin-3 produced fiber labeling in deep layers of all parahippocampal areas and some dispersed fibers in superficial layers. Double-labeling studies revealed that both hippocampal projecting and calcium-binding protein-positive (presumed GABAergic) neurons received a relaxin-3 NI innervation. Some of these fibers also displayed synaptophysin (Syn) immunoreactivity, consistent with the presence of the peptide at synapses; and relaxin-3-positive fibers containing Syn bouton-like staining were frequently observed in contact with hippocampal-projecting or calcium-binding protein-positive neuronal somata and more distal elements. Finally, in situ hybridization studies revealed that entorhinal neurons in the superficial layers, and to a lesser extent in deep layers, contain RXFP3 mRNA. Together, our data support functional actions of the NI/relaxin-3-parahippocampal innervation on processes related to memory, spatial navigation and contextual analysis.
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Affiliation(s)
- Cristina García-Díaz
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Isis Gil-Miravet
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Hector Albert-Gasco
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Aroa Mañas-Ojeda
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Francisco Ros-Bernal
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Esther Castillo-Gómez
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Francisco E Olucha-Bordonau
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
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18
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Zhang AM, Wellberg EA, Kopp JL, Johnson JD. Hyperinsulinemia in Obesity, Inflammation, and Cancer. Diabetes Metab J 2021; 45:285-311. [PMID: 33775061 PMCID: PMC8164941 DOI: 10.4093/dmj.2020.0250] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/23/2020] [Indexed: 12/13/2022] Open
Abstract
The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.
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Affiliation(s)
- Anni M.Y. Zhang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth A. Wellberg
- Department of Pathology, University of Oklahoma Health Sciences Center, Stephenson Cancer Center, Harold Hamm Diabetes Center, Oklahoma City, OK, USA
| | - Janel L. Kopp
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - James D. Johnson
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- Corresponding author: James D. Johnson https://orcid.org/0000-0002-7523-9433 Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2329 W Mall Vancouver, BC V6T 1Z4, Vancouver, BC, Canada E-mail:
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19
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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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20
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Mapping Cell Types and Efferent Pathways in the Ascending Relaxin-3 System of the Nucleus Incertus. eNeuro 2020; 7:ENEURO.0272-20.2020. [PMID: 33055197 PMCID: PMC7643772 DOI: 10.1523/eneuro.0272-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/30/2020] [Accepted: 08/20/2020] [Indexed: 12/14/2022] Open
Abstract
Relaxin-3 (Rln3) is an insulin-family peptide neurotransmitter expressed primarily in neurons of the nucleus incertus (NI) of the pontine tegmentum, with smaller populations located in the deep mesencephalon (DpMe) and periaqueductal gray (PAG). Here, we have used targeted recombination at the Rln3 gene locus to generate an Rln3Cre transgenic mouse line, and characterize the molecular identity and axonal projections of Rln3-expressing neurons. Expression of Cre recombinase in Rln3Cre mice, and the expression of Cre-mediated reporters, accurately reflect the expression of Rln3 mRNA in all brain regions. In the NI, Rln3 mRNA is expressed in a subset of a larger population of tegmental neurons that express the neuropeptide neuromedin-b (NMB). These Rln3-expressing and NMB-expressing neurons also express the GABAergic marker GAD2 but not the glutamatergic marker Slc17a6 (VGluT2). Cre-mediated anterograde tracing with adeno-associated viruses (AAVs) shows that the efferents of the Rln3-expressing neurons in the DpMe and PAG are largely confined to the brain regions in which they originate, while the NI-Rln3 neurons form an extensive ascending system innervating the limbic cortex, septum, hippocampus, and hypothalamus. Viral anterograde tracing also reveals the potential synaptic targets of NI-Rln3 neurons in several brain regions, and the distinct projections of Rln3-expressing and non-expressing neurons in the pontine tegmentum. Rabies virus (RV)-mediated transsynaptic retrograde tracing demonstrates a probable synaptic link between NI-Rln3 neurons and GABAergic neurons in the septum, with implications for the modulation of neural activity in the septo-hippocampal system. Together, these results form the basis for functional studies of the NI-Rln3 system.
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21
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Soltani Zangbar H, Ghadiri T, Vafaee MS, Ebrahimi Kalan A, Karimipour M, Fallahi S, Ghorbani M, Shahabi P. A potential entanglement between the spinal cord and hippocampus: Theta rhythm correlates with neurogenesis deficiency following spinal cord injury in male rats. J Neurosci Res 2020; 98:2451-2467. [DOI: 10.1002/jnr.24719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/02/2020] [Accepted: 08/08/2020] [Indexed: 01/12/2023]
Affiliation(s)
- Hamid Soltani Zangbar
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
| | - Tahereh Ghadiri
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | | | - Abbas Ebrahimi Kalan
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Mohammad Karimipour
- Department of Applied Cell Sciences Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Solmaz Fallahi
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Meysam Ghorbani
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Parviz Shahabi
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
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22
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Yang L, Li Y, Wu Y, Sun S, Song Q, Wei J, Sun L, Li M, Wang D, Zhou L. Rln3a is a prerequisite for spermatogenesis and fertility in male fish. J Steroid Biochem Mol Biol 2020; 197:105517. [PMID: 31678357 DOI: 10.1016/j.jsbmb.2019.105517] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/10/2019] [Accepted: 10/25/2019] [Indexed: 02/05/2023]
Abstract
The essential roles of Relaxin3 (RLN3) in energy homeostasis had been well investigated, while the mechanisms of RLN3 regulating reproduction remain to be elusive in mammals. Although two rln3 paralogues have been characterized in several teleosts, their functions still remain largely unknown. In this study, two paralogous rln3 genes, represented as rln3a and rln3b, were identified from the testis of Nile tilapia (Oreochromis niloticus). Rln3a was dominantly expressed in testis, while the most abundant rln3b expression was in brain. In situ hybridization demonstrated that rln3a is abundantly expressed in the Leydig cells of the testis. To understand the role of Rln3 in the testicular development, homologous null-rln3a gene mutant line was constructed by CRISPR/Cas9 technology. Morphological observation demonstrated that null mutation of rln3a gene caused testicular hypertrophy and a significant increase of GSI. However, a significant decrease of spermatogenic cells at different phases, i.e. spermatogonia, spermatocytes, spermatids and sperms was found. Silencing of rln3a gene repressed the expression of key genes in germ cell and Leydig cell. Deficiency of Rln3a led to the significant decrease of 11-KT production, which stimulated the up-regulation of both FSH and LH production in the pituitary via a negative feedback manner possibly. Mutation of rln3a in XY fish led to the hypogonadism with sperm deformation, significant decrease of fertility, and sperm motility, revealing as the high mortality of the offspring obtained by crossing the wild type female and rln3a-/- XY fish. Interestingly, recombinant human RLN3 injection significantly enhanced the sperm motility in rln3a-/- XY fish. Moreover, hCG treatment stimulated the expression of steroidogenic enzyme genes and 11-KT production, which were repressed by rln3a mutation in XY fish. Taken together, this study, for the first time by using a gene knockout model, proved that Rln3a is an indispensable mediator for androgen production in testis via HPG axis, and plays an essential role in spermatogenesis, sperm motility and male fertility in fish.
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Affiliation(s)
- Lanying Yang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yanlong Li
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - You Wu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Shaohua Sun
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Qiang Song
- Chongqing Three Gorges Central Hospital, Chongqing, 400715, China
| | - Jing Wei
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Lina Sun
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Minghui Li
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Deshou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China.
| | - Linyan Zhou
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China.
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23
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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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24
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Wykes AD, Ma S, Bathgate RAD, Gundlach AL. Targeted viral vector transduction of relaxin-3 neurons in the rat nucleus incertus using a novel cell-type specific promoter. IBRO Rep 2019; 8:1-10. [PMID: 31890981 PMCID: PMC6928288 DOI: 10.1016/j.ibror.2019.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/29/2019] [Indexed: 12/12/2022] Open
Abstract
Extensive, ascending relaxin-3-containing neural networks are present throughout the rat forebrain. Relaxin-3 signalling modulates complex behaviours and cognitive processes including feeding, anxiety and memory. We tested a 1736 bp promoter sequence for specific transgene expression in relaxin-3 neurons of rat nucleus incertus (NI). This promoter restricted m-Cherry marker expression to NI relaxin-3 neurons with 98% specificity. This targeted transgene delivery offers a versatile method for ongoing preclinical studies of relaxin-3 circuitry.
Modern neuroscience utilizes transgenic techniques extensively to study the activity and function of brain neural networks. A key feature of this approach is its compatibility with molecular methods for selective transgene expression in neuronal circuits of interest. Until now, such targeted transgenic approaches have not been applied to the extensive circuitry involving the neuropeptide, relaxin-3. Pharmacological and gene knock-out studies have revealed relaxin-3 signalling modulates interrelated behaviours and cognitive processes, including stress and anxiety, food and alcohol consumption, and spatial and social memory, highlighting the potential of this system as a therapeutic target. In the present study, we aimed to identify a promoter sequence capable of regulating cell-type specific transgene expression from an adeno-associated viral (AAV) vector in relaxin-3 neurons of the rat nucleus incertus (NI). In parallel to relaxin-3 promoter sequences, we also tested an AAV vector containing promoter elements for the tropomyosin receptor kinase A (TrkA) gene, as TrkA is co-expressed with relaxin-3 in rat NI neurons. Stereotaxic injection of an mCherry-expressing AAV vector revealed widespread non-specific TrkA promoter (880 bp) activity in and adjacent to the NI at 8 weeks post-treatment. In contrast, mCherry expression was successfully restricted to relaxin-3 NI neurons with 98% specificity using a 1736 bp relaxin-3 promoter. In addition to detailed anatomical mapping of NI relaxin-3 networks, illustrated here in association with GABAergic medial septum neurons, this method for targeted transgene delivery offers a versatile tool for ongoing preclinical studies of relaxin-3 circuitry.
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Affiliation(s)
- Alexander D Wykes
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Ross A D Bathgate
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
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25
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Silva C, McNaughton N. Are periaqueductal gray and dorsal raphe the foundation of appetitive and aversive control? A comprehensive review. Prog Neurobiol 2019; 177:33-72. [DOI: 10.1016/j.pneurobio.2019.02.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/19/2019] [Accepted: 02/08/2019] [Indexed: 12/28/2022]
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26
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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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27
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Haidar M, Tin K, Zhang C, Nategh M, Covita J, Wykes AD, Rogers J, Gundlach AL. Septal GABA and Glutamate Neurons Express RXFP3 mRNA and Depletion of Septal RXFP3 Impaired Spatial Search Strategy and Long-Term Reference Memory in Adult Mice. Front Neuroanat 2019; 13:30. [PMID: 30906254 PMCID: PMC6419585 DOI: 10.3389/fnana.2019.00030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 02/20/2019] [Indexed: 12/11/2022] Open
Abstract
Relaxin-3 is a highly conserved neuropeptide abundantly expressed in neurons of the nucleus incertus (NI), which project to nodes of the septohippocampal system (SHS) including the medial septum/diagonal band of Broca (MS/DB) and dorsal hippocampus, as well as to limbic circuits. High densities of the Gi/o-protein-coupled receptor for relaxin-3, known as relaxin-family peptide-3 receptor (RXFP3) are expressed throughout the SHS, further suggesting a role for relaxin-3/RXFP3 signaling in modulating learning and memory processes that occur within these networks. Therefore, this study sought to gain further anatomical and functional insights into relaxin-3/RXFP3 signaling in the mouse MS/DB. Using Cre/LoxP recombination methods, we assessed locomotion, exploratory behavior, and spatial learning and long-term reference memory in adult C57BL/6J Rxfp3 loxP/loxP mice with targeted depletion of Rxfp3 in the MS/DB. Following prior injection of an AAV(1/2)-Cre-IRES-eGFP vector into the MS/DB to delete/deplete Rxfp3 mRNA/RXFP3 protein, mice tested in a Morris water maze (MWM) displayed an impairment in allocentric spatial learning during acquisition, as well as an impairment in long-term reference memory on probe day. However, RXFP3-depleted and control mice displayed similar motor activity in a locomotor cell and exploratory behavior in a large open-field (LOF) test. A quantitative characterization using multiplex, fluorescent in situ hybridization (ISH) identified a high level of co-localization of Rxfp3 mRNA and vesicular GABA transporter (vGAT) mRNA in MS and DB neurons (~87% and ~95% co-expression, respectively). Rxfp3 mRNA was also detected, to a correspondingly lesser extent, in vesicular glutamate transporter 2 (vGlut2) mRNA-containing neurons in MS and DB (~13% and ~5% co-expression, respectively). Similarly, a qualitative assessment of the MS/DB region, identified Rxfp3 mRNA in neurons that expressed parvalbumin (PV) mRNA (reflecting hippocampally-projecting GABA neurons), whereas choline acetyltransferase mRNA-positive (acetylcholine) neurons lacked Rxfp3 mRNA. These data are consistent with a qualitative immunohistochemical analysis that revealed relaxin-3-immunoreactive nerve fibers in close apposition with PV-immunoreactive neurons in the MS/DB. Together these studies suggest relaxin-3/RXFP3 signaling in the MS/DB plays a role in modulating specific learning and long-term memory associated behaviors in adult mice via effects on GABAergic neuron populations known for their involvement in modulating hippocampal theta rhythm and associated cognitive processes.
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Affiliation(s)
- Mouna Haidar
- 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
| | - Kimberly Tin
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Cary Zhang
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Mohsen Nategh
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - João Covita
- 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
| | - Alexander D. Wykes
- 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
| | - Jake Rogers
- 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
| | - 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
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
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28
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Watson C, Bartholomaeus C, Puelles L. Time for Radical Changes in Brain Stem Nomenclature-Applying the Lessons From Developmental Gene Patterns. Front Neuroanat 2019; 13:10. [PMID: 30809133 PMCID: PMC6380082 DOI: 10.3389/fnana.2019.00010] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/22/2019] [Indexed: 01/25/2023] Open
Abstract
The traditional subdivision of the brain stem into midbrain, pons, and medulla oblongata is based purely on the external appearance of the human brain stem. There is an urgent need to update the names of brain stem structures to be consistent with the discovery of rhomobomeric segmentation based on gene expression. The most important mistakes are the belief that the pons occupies the upper half of the hindbrain, the failure to recognize the isthmus as the first segment of the hindbrain, and the mistaken inclusion of diencephalic structures in the midbrain. The new nomenclature will apply to all mammals. This essay recommends a new brain stem nomenclature based on developmental gene expression, progeny analysis, and fate mapping. In addition, we have made comment on the names given to a number of internal brain stem structures and have offered alternatives where necessary.
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Affiliation(s)
- Charles Watson
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
- Neuroscience Research Australia, The University of New South Wales, Sydney, NSW, Australia
| | - Caitlin Bartholomaeus
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Luis Puelles
- Department of Human Anatomy and IMIB-Arrixaca Institute, School of Medicine, University of Murcia, Murcia, Spain
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29
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Lawther AJ, Flavell A, Ma S, Kent S, Lowry CA, Gundlach AL, Hale MW. Involvement of Serotonergic and Relaxin-3 Neuropeptide Systems in the Expression of Anxiety-like Behavior. Neuroscience 2018; 390:88-103. [DOI: 10.1016/j.neuroscience.2018.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/12/2018] [Accepted: 08/07/2018] [Indexed: 12/12/2022]
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30
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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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31
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Solari N, Hangya B. Cholinergic modulation of spatial learning, memory and navigation. Eur J Neurosci 2018; 48:2199-2230. [PMID: 30055067 PMCID: PMC6174978 DOI: 10.1111/ejn.14089] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/25/2018] [Accepted: 07/23/2018] [Indexed: 01/02/2023]
Abstract
Spatial learning, including encoding and retrieval of spatial memories as well as holding spatial information in working memory generally serving navigation under a broad range of circumstances, relies on a network of structures. While central to this network are medial temporal lobe structures with a widely appreciated crucial function of the hippocampus, neocortical areas such as the posterior parietal cortex and the retrosplenial cortex also play essential roles. Since the hippocampus receives its main subcortical input from the medial septum of the basal forebrain (BF) cholinergic system, it is not surprising that the potential role of the septo-hippocampal pathway in spatial navigation has been investigated in many studies. Much less is known of the involvement in spatial cognition of the parallel projection system linking the posterior BF with neocortical areas. Here we review the current state of the art of the division of labour within this complex 'navigation system', with special focus on how subcortical cholinergic inputs may regulate various aspects of spatial learning, memory and navigation.
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Affiliation(s)
- Nicola Solari
- Lendület Laboratory of Systems NeuroscienceDepartment of Cellular and Network NeurobiologyInstitute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
| | - Balázs Hangya
- Lendület Laboratory of Systems NeuroscienceDepartment of Cellular and Network NeurobiologyInstitute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
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32
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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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33
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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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34
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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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35
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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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36
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Dexmedetomidine promotes the recovery of neurogenesis in aged mouse with postoperative cognitive dysfunction. Neurosci Lett 2018; 677:110-116. [PMID: 29571823 DOI: 10.1016/j.neulet.2018.03.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 03/17/2018] [Accepted: 03/19/2018] [Indexed: 11/21/2022]
Abstract
Recently, growing evidence has demonstrated Dexmedetomidine (Dex) a promising intervene preventing postoperative cognitive decline (POCD) following surgery, which is associated with neuroinflammation leading to neuronal apoptosis and deregulated neurogenesis. Previous studies suggested the anti-inflammation and anti-neuroapoptosis action of Dex. Therefore we hypothesize the promoting neurogenesis of Dex linked to stimulating BDNF and subsequent p-MPAK production in a rat model of POCD. In the present study, the POCD animal model was established by performing an exploratory laparotomy under isoflurane anaesthesia in old rats, utilizing which Dex response is confirmed by behavioural tests. Inflammatory biomarkers as IL-1β and TNF-α, mature neuron percentage measured by doublecortin staining (DCX), promoting factors as brain derived growth factor (BDNF), phosphorylated cAMP response element binding protein (CREB) and proteins of kinase A (PKA), MAPK production as p-P38-MAPK protein express were measured. Herein, we showed that surgery reduced DCX-positive neurons and expression of BDNF representing neurogenesis profoundly. As expected, Dex rescued the associated cognitive impairment and inflammatory changes, as well as up-regulated expression of BDNF, PKA, p-CREB/CREB and following p-P38-MAPK regulation. Our results confirmed the protective Dex response and indicated the proneurogenesis role of it as well, suggesting the mechanism of beneficial effects of Dex to prevent POCD.
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37
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Ma S, Hangya B, Leonard CS, Wisden W, Gundlach AL. Dual-transmitter systems regulating arousal, attention, learning and memory. Neurosci Biobehav Rev 2018; 85:21-33. [PMID: 28757457 PMCID: PMC5747977 DOI: 10.1016/j.neubiorev.2017.07.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/16/2017] [Indexed: 01/12/2023]
Abstract
An array of neuromodulators, including monoamines and neuropeptides, regulate most behavioural and physiological traits. In the past decade, dramatic progress has been made in mapping neuromodulatory circuits, in analysing circuit dynamics, and interrogating circuit function using pharmacogenetic, optogenetic and imaging methods This review will focus on several distinct neural networks (acetylcholine/GABA/glutamate; histamine/GABA; orexin/glutamate; and relaxin-3/GABA) that originate from neural hubs that regulate wakefulness and related attentional and cognitive processes, and highlight approaches that have identified dual transmitter roles in these behavioural functions. Modulation of these different neural networks might be effective treatments of diseases related to arousal/sleep dysfunction and of cognitive dysfunction in psychiatric and neurodegenerative disorders.
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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.
| | - Balázs Hangya
- 'Lendület' Laboratory of Systems Neuroscience, Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - William Wisden
- Department of Life Sciences, Imperial College London, London, UK
| | - 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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38
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Albert-Gascó H, Ma S, Ros-Bernal F, Sánchez-Pérez AM, Gundlach AL, Olucha-Bordonau FE. GABAergic Neurons in the Rat Medial Septal Complex Express Relaxin-3 Receptor (RXFP3) mRNA. Front Neuroanat 2018; 11:133. [PMID: 29403361 PMCID: PMC5777284 DOI: 10.3389/fnana.2017.00133] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/18/2017] [Indexed: 11/13/2022] Open
Abstract
The medial septum (MS) complex modulates hippocampal function and related behaviors. Septohippocampal projections promote and control different forms of hippocampal synchronization. Specifically, GABAergic and cholinergic projections targeting the hippocampal formation from the MS provide bursting discharges to promote theta rhythm, or tonic activity to promote gamma oscillations. In turn, the MS is targeted by ascending projections from the hypothalamus and brainstem. One of these projections arises from the nucleus incertus in the pontine tegmentum, which contains GABA neurons that co-express the neuropeptide relaxin-3 (Rln3). Both stimulation of the nucleus incertus and septal infusion of Rln3 receptor agonist peptides promotes hippocampal theta rhythm. The Gi/o-protein-coupled receptor, relaxin-family peptide receptor 3 (RXFP3), is the cognate receptor for Rln3 and identification of the transmitter phenotype of neurons expressing RXFP3 in the septohippocampal system can provide further insights into the role of Rln3 transmission in the promotion of septohippocampal theta rhythm. Therefore, we used RNAscope multiplex in situ hybridization to characterize the septal neurons expressing Rxfp3 mRNA in the rat. Our results demonstrate that Rxfp3 mRNA is abundantly expressed in vesicular GABA transporter (vGAT) mRNA- and parvalbumin (PV) mRNA-positive GABA neurons in MS, whereas ChAT mRNA-positive acetylcholine neurons lack Rxfp3 mRNA. Approximately 75% of Rxfp3 mRNA-positive neurons expressed vGAT mRNA (and 22% were PV mRNA-positive), while the remaining 25% expressed Rxfp3 mRNA only, consistent with a potential glutamatergic phenotype. Similar proportions were observed in the posterior septum. The occurrence of RXFP3 in PV-positive GABAergic neurons gives support to a role for the Rln3-RXFP3 system in septohippocampal theta rhythm.
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Affiliation(s)
- Hector Albert-Gascó
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón, Spain.,The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Francisco Ros-Bernal
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón, Spain
| | - Ana M Sánchez-Pérez
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, 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, Melbourne, VIC, Australia
| | - Francisco E Olucha-Bordonau
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón, Spain
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39
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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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40
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Lima LB, Bueno D, Leite F, Souza S, Gonçalves L, Furigo IC, Donato J, Metzger M. Afferent and efferent connections of the interpeduncular nucleus with special reference to circuits involving the habenula and raphe nuclei. J Comp Neurol 2017; 525:2411-2442. [DOI: 10.1002/cne.24217] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Leandro B. Lima
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Debora Bueno
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Fernanda Leite
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Stefani Souza
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Luciano Gonçalves
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Isadora C. Furigo
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Jose Donato
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
| | - Martin Metzger
- Department of Physiology & Biophysics; Institute of Biomedical Sciences, University of São Paulo; São Paulo Brazil
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41
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Haidar M, Guèvremont G, Zhang C, Bathgate RAD, Timofeeva E, Smith CM, Gundlach AL. Relaxin-3 inputs target hippocampal interneurons and deletion of hilar relaxin-3 receptors in "floxed-RXFP3" mice impairs spatial memory. Hippocampus 2017; 27:529-546. [PMID: 28100033 DOI: 10.1002/hipo.22709] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 11/10/2022]
Abstract
Hippocampus is innervated by γ-aminobutyric acid (GABA) "projection" neurons of the nucleus incertus (NI), including a population expressing the neuropeptide, relaxin-3 (RLN3). In studies aimed at gaining an understanding of the role of RLN3 signaling in hippocampus via its Gi/o -protein-coupled receptor, RXFP3, we examined the distribution of RLN3-immunoreactive nerve fibres and RXFP3 mRNA-positive neurons in relation to hippocampal GABA neuron populations. RLN3-positive elements were detected in close-apposition with a substantial population of somatostatin (SST)- and GABA-immunoreactive neurons, and a smaller population of parvalbumin- and calretinin-immunoreactive neurons in different hippocampal areas, consistent with the relative distribution patterns of RXFP3 mRNA and these marker transcripts. In light of the functional importance of the dentate gyrus (DG) hilus in learning and memory, and our anatomical data, we examined the possible influence of RLN3/RXFP3 signaling in this region on spatial memory. Using viral-based Cre/LoxP recombination methods and adult mice with a floxed Rxfp3 gene, we deleted Rxfp3 from DG hilar neurons and assessed spatial memory performance and affective behaviors. Following infusions of an AAV(1/2) -Cre-IRES-eGFP vector, Cre expression was observed in DG hilar neurons, including SST-positive cells, and in situ hybridization histochemistry for RXFP3 mRNA confirmed receptor depletion relative to levels in floxed-RXFP3 mice infused with an AAV(1/2) -eGFP (control) vector. RXFP3 depletion within the DG hilus impaired spatial reference memory in an appetitive T-maze task reflected by a reduced percentage of correct choices and increased time to meet criteria, relative to control. In a continuous spontaneous alternation Y-maze task, RXFP3-depleted mice made fewer alternations in the first minute, suggesting impairment of spatial working memory. However, RXFP3-depleted and control mice displayed similar locomotor activity, anxiety-like behavior in light/dark box and elevated-plus maze tests, and learning and long-term memory retention in the Morris water maze. These data indicate endogenous RLN3/RXFP3 signaling can modulate hippocampal-dependent spatial reference and working memory via effects on SST interneurons, and further our knowledge of hippocampal cognitive processing. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- M Haidar
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - G Guèvremont
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Quebec, Canada
| | - C Zhang
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - R A D Bathgate
- 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 Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
| | - E Timofeeva
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Quebec, Canada
| | - C 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, Victoria, Australia
| | - A 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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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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Jayakody T, Marwari S, Lakshminarayanan R, Tan FCK, Johannes CW, Dymock BW, Poulsen A, Herr DR, Dawe GS. Hydrocarbon stapled B chain analogues of relaxin-3 retain biological activity. Peptides 2016; 84:44-57. [PMID: 27498038 DOI: 10.1016/j.peptides.2016.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 07/29/2016] [Accepted: 08/02/2016] [Indexed: 11/30/2022]
Abstract
Relaxin-3 or insulin-like peptide 7 (INSL7) is the most recently discovered relaxin/insulin-like family peptide. Mature relaxin-3 consists of an A chain and a B chain held by disulphide bonds. According to structure activity relationship studies, the relaxin-3 B chain is more important in binding and activating the receptor. RXFP3 (also known as Relaxin-3 receptor 1, GPCR 135, somatostatin- and angiotensin- like peptide receptor or SALPR) was identified as the cognate receptor for relaxin-3 by expression profiles and binding studies. Recent studies imply roles of this system in mediating stress and anxiety, feeding, metabolism and cognition. Stapling of peptides is a technique used to develop peptide drugs for otherwise undruggable targets. The main advantages of stapling include, increased activity due to reduced proteolysis, increased affinity to receptors and increased cell permeability. Stable agonists and antagonists of RXFP3 are crucial for understanding the physiological significance of this system. So far, agonists and antagonists of RXFP3 are peptides. In this study, for the first time, we have introduced stapling of the relaxin-3 B chain at 14th and 18th positions (14s18) and 18th and 22nd position (18s22). These stapled peptides showed greater helicity than the unstapled relaxin-3 B chain in circular dichroism analysis. Both stapled peptides bound RXFP3 and activated RXFP3 as observed in an inhibition of forskolin-induced cAMP assay and a ERK1/2 activation assay, although with different potencies. Therefore, we conclude that stapling of the relaxin3 B chain does not compromise its ability to activate RXFP3 and is a promising method for developing stable peptide agonists and antagonists of RXFP3 to aid relaxin-3/RXFP3 research.
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Affiliation(s)
- 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), National University of Singapore, Singapore
| | - Subhi Marwari
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore
| | - Rajamani Lakshminarayanan
- Singapore Eye Research Institute, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Francis Chee Kuan Tan
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Charles William Johannes
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Brian William Dymock
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore
| | - Anders Poulsen
- Department of Medicinal Chemistry, Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Deron Raymond Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - 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; Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, Singapore.
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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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45
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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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Ma S, Allocca G, Ong-Pålsson EKE, Singleton CE, Hawkes D, McDougall SJ, Williams SJ, Bathgate RAD, Gundlach AL. Nucleus incertus promotes cortical desynchronization and behavioral arousal. Brain Struct Funct 2016; 222:515-537. [PMID: 27206427 DOI: 10.1007/s00429-016-1230-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 04/26/2016] [Indexed: 01/09/2023]
Abstract
Arousal and vigilance are essential for survival and relevant regulatory neural circuits lie within the brainstem, hypothalamus and forebrain. The nucleus incertus (NI) is a distinct site within the pontine periventricular gray, containing a substantial population of GABAergic neurons with long-range, ascending projections. Existing neuroanatomical data and functional studies in anesthetized rats, suggest the NI is a central component of a midline behavioral control network well positioned to modulate arousal, vigilance and exploratory navigation, yet none of these roles have been established experimentally. We used a chemogenetic approach-clozapine-N-oxide (CNO) activation of virally delivered excitatory hM3Dq-DREADDs-to activate the NI in rats and examined the behavioral and physiological effects, relative to effects in naïve rats and appropriate viral-treated controls. hM3Dq activation by CNO resulted in long-lasting depolarization of NI neurons with action potentials, in vitro. Peripheral injection of CNO significantly increased c-Fos immunoreactivity in the NI and promoted cortical electroencephalograph (EEG) desynchronization. These brain changes were associated with heightened arousal, and increased locomotor activity in the homecage and in a novel environment. Furthermore, NI activation altered responses in a fear conditioning paradigm, reflected by increased head-scanning, vigilant behaviors during conditioned fear recall. These findings provide direct evidence that the NI promotes general arousal via a broad behavioral activation circuit and support early hypotheses, based on its connectivity, that the NI is a modulator of cognition and attention, and emotional and motivated behaviors.
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Affiliation(s)
- Sherie Ma
- 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, Australia.
| | - Giancarlo Allocca
- 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, Australia
| | - Emma K E Ong-Pålsson
- 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, Australia
| | - Caitlin E Singleton
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - David Hawkes
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC, Australia
| | - Stuart J McDougall
- 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, Australia
| | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Ross A D Bathgate
- 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, Australia.,Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, VIC, Australia
| | - 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, Australia. .,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia.
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47
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Central relaxin-3 receptor (RXFP3) activation increases ERK phosphorylation in septal cholinergic neurons and impairs spatial working memory. Brain Struct Funct 2016; 222:449-463. [PMID: 27146679 DOI: 10.1007/s00429-016-1227-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/12/2016] [Indexed: 01/09/2023]
Abstract
The medial septum/diagonal band (MS/DB) is a relay region connecting the hypothalamus and brainstem with the hippocampus, and both the MS/DB and dorsal/ventral hippocampus receive strong topographic GABA/peptidergic projections from the nucleus incertus of the pontine tegmentum. The neuropeptide relaxin-3, released by these neurons, is the cognate ligand for a Gi/o-protein-coupled receptor, RXFP3, which is highly expressed within the MS/DB, and both cholinergic and GABAergic neurons in this region of rat brain receive relaxin-3 positive terminals/boutons. Comprehensive in vitro studies have demonstrated that the cell signaling pathways altered by RXFP3 stimulation, include inhibition of forskolin-activated cAMP levels and activation of ERK phosphorylation. In this study we investigated whether intracerebroventricular (icv) injection of RXFP3-A2, a selective relaxin-3 receptor agonist, altered ERK phosphorylation levels in the MS/DB of adult male rats. We subsequently assessed the neurochemical phenotype of phosphorylated (p) ERK-positive neurons in MS/DB after icv RXFP3-A2 administration by dual-label immunostaining for pERK and neuronal markers for cholinergic and GABAergic neurons. Central RXFP3-A2 injection significantly increased levels of pERK immunoreactivity (IR) in MS/DB at 20 and 90 min post-injection, compared to vehicle and naive levels. In addition, RXFP3-A2 increased the number of cells expressing pERK-IR in the MS/DB at 90 (but not 20) min post-injection in cholinergic (but not GABAergic) neurons, which also expressed putative RXFP3-IR. Moreover, icv injection of RXFP3-A2 impaired alternation in a delayed spontaneous T-maze test of spatial working memory. The presence of RXFP3-like IR and the RXFP3-related activation of the MAPK/ERK pathway in MS/DB cholinergic neurons identifies them as a key target of ascending relaxin-3 projections with implications for the acute and chronic modulation of cholinergic neuron activity and function by relaxin-3/RXFP3 signaling.
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Santos FN, Pereira CW, Sánchez-Pérez AM, Otero-García M, Ma S, Gundlach AL, Olucha-Bordonau FE. Comparative Distribution of Relaxin-3 Inputs and Calcium-Binding Protein-Positive Neurons in Rat Amygdala. Front Neuroanat 2016; 10:36. [PMID: 27092060 PMCID: PMC4823275 DOI: 10.3389/fnana.2016.00036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/17/2016] [Indexed: 01/16/2023] Open
Abstract
The neural circuits involved in mediating complex behaviors are being rapidly elucidated using various newly developed and powerful anatomical and molecular techniques, providing insights into the neural basis for anxiety disorders, depression, addiction, and dysfunctional social behaviors. Many of these behaviors and associated physiological processes involve the activation of the amygdala in conjunction with cortical and hippocampal circuits. Ascending subcortical projections provide modulatory inputs to the extended amygdala and its related nodes (or "hubs") within these key circuits. One such input arises from the nucleus incertus (NI) in the tegmentum, which sends amino acid- and peptide-containing projections throughout the forebrain. Notably, a distinct population of GABAergic NI neurons expresses the highly-conserved neuropeptide, relaxin-3, and relaxin-3 signaling has been implicated in the modulation of reward/motivation and anxiety- and depressive-like behaviors in rodents via actions within the extended amygdala. Thus, a detailed description of the relaxin-3 innervation of the extended amygdala would provide an anatomical framework for an improved understanding of NI and relaxin-3 modulation of these and other specific amygdala-related functions. Therefore, in this study, we examined the distribution of NI projections and relaxin-3-positive elements (axons/fibers/terminals) within the amygdala, relative to the distribution of neurons expressing the calcium-binding proteins, parvalbumin (PV), calretinin (CR) and/or calbindin. Anterograde tracer injections into the NI revealed a topographic distribution of NI efferents within the amygdala that was near identical to the distribution of relaxin-3-immunoreactive fibers. Highest densities of anterogradely-labeled elements and relaxin-3-immunoreactive fibers were observed in the medial nucleus of the amygdala, medial divisions of the bed nucleus of the stria terminalis (BST) and in the endopiriform nucleus. In contrast, sparse anterogradely-labeled and relaxin-3-immunoreactive fibers were observed in other amygdala nuclei, including the lateral, central and basal nuclei, while the nucleus accumbens lacked any innervation. Using synaptophysin as a synaptic marker, we identified relaxin-3 positive synaptic terminals in the medial amygdala, BST and endopiriform nucleus of amygdala. Our findings demonstrate the existence of topographic NI and relaxin-3-containing projections to specific nuclei of the extended amygdala, consistent with a likely role for this putative integrative arousal system in the regulation of amygdala-dependent social and emotional behaviors.
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Affiliation(s)
- Fabio N Santos
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universitat ValenciaValencia, Spain; Centro de Ciências Biológicas e da Saúde, Universidade TiradentesAracaju, Brazil
| | - Celia W Pereira
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universitat ValenciaValencia, Spain; Centro de Ciências Biológicas e da Saúde, Universidade TiradentesAracaju, Brazil
| | | | - Marcos Otero-García
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universitat Valencia Valencia, Spain
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia; Florey Department of Neuroscience and Mental Health and Department of Anatomy and Neuroscience, The University of MelbourneMelbourne, VIC, Australia
| | - Francisco E Olucha-Bordonau
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universitat ValenciaValencia, Spain; Unitat Predepartamental de Medicina, Universitat Jaume ICastellón, Spain
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Farooq U, Kumar JR, Rajkumar R, Dawe GS. Electrical microstimulation of the nucleus incertus induces forward locomotion and rotation in rats. Physiol Behav 2016; 160:50-8. [PMID: 27049117 DOI: 10.1016/j.physbeh.2016.03.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/01/2016] [Accepted: 03/29/2016] [Indexed: 12/27/2022]
Abstract
Locomotion is essential for goal-oriented behavior. Theta frequency oscillations in the hippocampus have been associated with behavioral activation and initiation of movement. Recently, the nucleus incertus, a brainstem nucleus with widespread cortical and subcortical projections, has been reported to modulate the septo-hippocampal axis triggering theta activity in the hippocampus. This suggests that activation of the nucleus incertus would induce movement. In this study, we investigated the effects of electrical microstimulation of the nucleus incertus on locomotion in conscious rats. Rats chronically implanted with microelectrodes targeting the nucleus incertus were electrically stimulated while their behavior was tracked. High frequency electrical microstimulation of the nucleus incertus was sufficient to induce forward locomotion and rotation. The latencies of evoked locomotion were consistent with a role of the nucleus incertus in modulating premotor areas, possibly the septo-hippocampal axis. Electrical microstimulation of the nucleus incertus increased velocity, mobility and rotations during stimulation and post-stimulation. These results suggest that the nucleus incertus plays a role in behavioral activation and locomotion.
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Affiliation(s)
- Usman Farooq
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
| | - Jigna Rajesh Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
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50
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Inactivation of nucleus incertus impairs passive avoidance learning and long term potentiation of the population spike in the perforant path-dentate gyrus evoked field potentials in rats. Neurobiol Learn Mem 2016; 130:185-93. [PMID: 26927304 DOI: 10.1016/j.nlm.2016.02.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 02/14/2016] [Accepted: 02/20/2016] [Indexed: 11/21/2022]
Abstract
Involvement of brainstem nucleus incertus (NI) in hippocampal theta rhythm suggests that this structure might play a role in hippocampal-dependent learning and memory. In the present study we aimed to address if NI is involved in an avoidance learning task as well as dentate gyrus (DG) short-term and long-term potentiation. Lidocaine was injected into the NI to transiently inactivate the nucleus, and control rats received saline. Role of NI was studied in passive avoidance learning (PAL) in 3 memory phases of acquisition, consolidation and retrieval. Levels of hippocampal phosphorylated p70 were also assessed in rats involved in PAL. Perforant path-DG short-term synaptic plasticity was studied upon NI inactivation before the paired-pulse stimulation, and also before or after tetanic stimulation in freely moving rats. It was found that NI inactivation delayed learning and impaired retention in the PAL task, with decreased levels of phosphorylated p70 in the respective groups. However, short-term plasticity was not affected by NI inactivation. But long term potentiation (LTP) of DG population spike was poorly induced with NI inactivation compared to the saline group, and it had no effect on population excitatory post-synaptic potential. Furthermore, when NI was inactivated after the induction of LTP, there was no difference between the saline and lidocaine groups. These observations suggest that NI has a role in PAL task, and its inactivation does not change the perforant path-DG granule cell synaptic input but decreases the excitability of the DG granule cells. Further studies should elucidate direct and indirect paths through which NI might influence hippocampal activity.
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