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Piñon Gonzalez VM, Feng Y, Egertová M, Elphick MR. Neuropeptide expression and action in the reproductive system of the starfish Asterias rubens. J Comp Neurol 2024; 532:e25585. [PMID: 38289190 DOI: 10.1002/cne.25585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 02/01/2024]
Abstract
Reproductive processes are regulated by a variety of neuropeptides in vertebrates and invertebrates. In starfish (phylum Echinodermata), relaxin-like gonad-stimulating peptide triggers oocyte maturation and spawning. However, little is known about other neuropeptides as potential regulators of reproduction in starfish. To address this issue, here, we used histology and immunohistochemistry to analyze the reproductive system of the starfish Asterias rubens at four stages of the seasonal reproductive cycle in male and female animals, investigating the expression of eight neuropeptides: the corticotropin-releasing hormone-type neuropeptide ArCRH, the calcitonin-type neuropeptide ArCT, the pedal peptide-type neuropeptides ArPPLN1b and ArPPLN2h, the vasopressin/ocytocin-type neuropeptide asterotocin, the gonadotropin-releasing hormone-type neuropeptide ArGnRH, and the somatostatin/allatostatin-C-type neuropeptides ArSS1 and ArSS2. The expression of five neuropeptides, ArCRH, ArCT, ArPPLN1b, ArPPLN2h, and asterotocin, was detected in the gonoducts and/or gonads. For example, extensive ArPPLN2h expression was revealed in the coelomic epithelial layer of the gonads throughout the seasonal reproductive cycle in both males and females. However, seasonal and/or sexual differences in the patterns of neuropeptide expression were also observed. Informed by these findings, the in vitro pharmacological effects of neuropeptides on gonad preparations from male and female starfish were investigated. This revealed that ArSS1 causes gonadal contraction and that ArPPLN2h causes gonadal relaxation, with both neuropeptides being more effective on ovaries than testes. Collectively, these findings indicate that multiple neuropeptide signaling systems are involved in the regulation of reproductive function in starfish, with some neuropeptides exerting excitatory or inhibitory effects on gonad contractility that may be physiologically relevant when gametes are expelled during spawning.
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Affiliation(s)
| | - Yuling Feng
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, UK
| | - Michaela Egertová
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, UK
| | - Maurice R Elphick
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, UK
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2
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Feng Y, Piñon Gonzalez VM, Lin M, Egertová M, Mita M, Elphick MR. Localization of relaxin-like gonad-stimulating peptide expression in starfish reveals the gonoducts as a source for its role as a regulator of spawning. J Comp Neurol 2023; 531:1299-1316. [PMID: 37212624 PMCID: PMC10952978 DOI: 10.1002/cne.25496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/17/2023] [Accepted: 04/26/2023] [Indexed: 05/23/2023]
Abstract
Oocyte maturation and gamete release (spawning) in starfish are triggered by relaxin-like gonad-stimulating peptide (RGP), a neuropeptide that was first isolated from the radial nerve cords of these animals. Hitherto, it has generally been assumed that the radial nerve cords are the source of RGP that triggers spawning physiologically. To investigate other sources of RGP, here we report the first comprehensive anatomical analysis of its expression, using both in situ hybridization and immunohistochemistry to map RGP precursor transcripts and RGP, respectively, in the starfish Asterias rubens. Cells expressing RGP precursor transcripts were revealed in the ectoneural epithelium of the radial nerve cords and circumoral nerve ring, arm tips, tube feet, cardiac stomach, pyloric stomach, and, most notably, gonoducts. Using specific antibodies to A. rubens RGP, immunostaining was revealed in cells and/or fibers in the ectoneural region of the radial nerve cords and circumoral nerve ring, tube feet, terminal tentacle and other arm tip-associated structures, body wall, peristomial membrane, esophagus, cardiac stomach, pyloric stomach, pyloric caeca, and gonoducts. Our discovery that RGP is expressed in the gonoducts of A. rubens proximal to its gonadotropic site of action in the gonads is important because it provides a new perspective on how RGP may act as a gonadotropin in starfish. Thus, we hypothesize that it is the release of RGP from the gonoducts that triggers gamete maturation and spawning in starfish, while RGP produced in other parts of the body may regulate other physiological/behavioral processes.
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Affiliation(s)
- Yuling Feng
- School of Biological & Behavioural SciencesQueen Mary University of LondonLondonUK
| | | | - Ming Lin
- School of Biological & Behavioural SciencesQueen Mary University of LondonLondonUK
| | - Michaela Egertová
- School of Biological & Behavioural SciencesQueen Mary University of LondonLondonUK
| | - Masatoshi Mita
- Department of BiochemistryShowa University School of MedicineTokyoJapan
| | - Maurice R. Elphick
- School of Biological & Behavioural SciencesQueen Mary University of LondonLondonUK
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3
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Cai W, Egertová M, Zampronio CG, Jones AM, Elphick MR. Molecular Identification and Cellular Localization of a Corticotropin-Releasing Hormone-Type Neuropeptide in an Echinoderm. Neuroendocrinology 2023; 113:231-250. [PMID: 33965952 DOI: 10.1159/000517087] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/30/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Corticotropin-releasing hormone (CRH) mediates physiological responses to stressors in mammals by triggering pituitary secretion of adrenocorticotropic hormone, which stimulates adrenal release of cortisol. CRH belongs to a family of related neuropeptides that include sauvagine, urotensin-I, and urocortins in vertebrates and the diuretic hormone DH44 in insects, indicating that the evolutionary origin of this neuropeptide family can be traced to the common ancestor of the Bilateria. However, little is known about CRH-type neuropeptides in deuterostome invertebrates. METHODS Here, we used mass spectrometry, mRNA in situ hybridization, and immunohistochemistry to investigate the structure and expression of a CRH-type neuropeptide (ArCRH) in the starfish Asterias rubens (phylum Echinodermata). RESULTS ArCRH is a 40-residue peptide with N-terminal pyroglutamylation and C-terminal amidation, and it has a widespread pattern of expression in A. rubens. In the central nervous system comprising the circumoral nerve ring and 5 radial nerve cords, ArCRH-expressing cells and fibres were revealed in both the ectoneural region and the hyponeural region, which contains the cell bodies of motoneurons. Accordingly, ArCRH immunoreactivity was detected in innervation of the ampulla and podium of locomotory organs (tube feet), and ArCRH is the first neuropeptide to be identified as a marker for nerve fibres located in the muscle layer of these organs. ArCRH immunoreactivity was also revealed in protractile organs that mediate gas exchange (papulae), the apical muscle, and the digestive system. CONCLUSIONS Our findings provide the first insights into CRH-type neuropeptide expression and function in the unique context of the pentaradially symmetrical body plan of an echinoderm.
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Affiliation(s)
- Weigang Cai
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
| | - Michaela Egertová
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Maurice R Elphick
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
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4
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Tinoco AB, Egertová M, Elphick MR. Immunohistochemical localisation of vasopressin/oxytocin-type, corazonin-type and luqin-type neuropeptide expression in the starfish Asterias rubens using antibodies to the C-terminal region of precursor proteins. Cell Tissue Res 2023; 391:441-456. [PMID: 36653662 PMCID: PMC9974683 DOI: 10.1007/s00441-023-03738-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/08/2023] [Indexed: 01/20/2023]
Abstract
Neuropeptides derived from larger precursor proteins are secreted as signalling molecules by neurons and regulate diverse physiological and behavioural processes in animals. Recently, we reported the discovery of ArCRZ (HNTFTMGGQNRWKAG-NH2) and ArLQ (EEKTRFPKFMRW-NH2)-novel neuropeptides in the starfish Asterias rubens that are orthologs of arthropod corazonins and molluscan luqins, respectively. However, our efforts to generate antibodies to ArCRZ and ArLQ have been unsuccessful, precluding immunohistochemical analysis of their expression. Here, we investigated an alternative experimental approach for neuropeptide immunohistochemistry by generating antibodies to peptides corresponding to the C-terminal region of the precursor proteins. As proof of principle, we generated antibodies to the C-terminal region of the precursor of the vasopressin/oxytocin-type neuropeptide asterotocin and show that these reveal immunostaining in A. rubens that is very similar to that observed with asterotocin antibodies. Furthermore, antibodies to the C-terminal region of the ArCRZ precursor (ArCRZP) and the ArLQ precursor (ArLQP) produced patterns of immunostaining consistent, respectively, with the distribution of ArCRZP and ArLQP transcripts revealed by mRNA in situ hybridisation. Detailed immunohistochemical analysis revealed widespread expression of ArCRZP and ArLQP in A. rubens, including the central nervous system, digestive system and the body wall and its associated appendages (e.g. tube feet), providing a neuroanatomical framework for investigation and interpretation of the pharmacological actions of ArCRZ and ArLQ in A. rubens. Furthermore, our findings provide a basis for use of antibodies to the C-terminal region of neuropeptide precursor proteins in other species where the production of antibodies to the bioactive neuropeptides is unsuccessful.
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Affiliation(s)
- Ana B Tinoco
- School of Biological & Behavioural Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Michaela Egertová
- School of Biological & Behavioural Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Maurice R Elphick
- School of Biological & Behavioural Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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Aleotti A, Wilkie IC, Yañez-Guerra LA, Gattoni G, Rahman TA, Wademan RF, Ahmad Z, Ivanova DA, Semmens DC, Delroisse J, Cai W, Odekunle E, Egertová M, Ferrario C, Sugni M, Bonasoro F, Elphick MR. Discovery and functional characterization of neuropeptides in crinoid echinoderms. Front Neurosci 2022; 16:1006594. [PMID: 36583101 PMCID: PMC9793003 DOI: 10.3389/fnins.2022.1006594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/09/2022] [Indexed: 12/14/2022] Open
Abstract
Neuropeptides are one of the largest and most diverse families of signaling molecules in animals and, accordingly, they regulate many physiological processes and behaviors. Genome and transcriptome sequencing has enabled the identification of genes encoding neuropeptide precursor proteins in species from a growing variety of taxa, including bilaterian and non-bilaterian animals. Of particular interest are deuterostome invertebrates such as the phylum Echinodermata, which occupies a phylogenetic position that has facilitated reconstruction of the evolution of neuropeptide signaling systems in Bilateria. However, our knowledge of neuropeptide signaling in echinoderms is largely based on bioinformatic and experimental analysis of eleutherozoans-Asterozoa (starfish and brittle stars) and Echinozoa (sea urchins and sea cucumbers). Little is known about neuropeptide signaling in crinoids (feather stars and sea lilies), which are a sister clade to the Eleutherozoa. Therefore, we have analyzed transcriptome/genome sequence data from three feather star species, Anneissia japonica, Antedon mediterranea, and Florometra serratissima, to produce the first comprehensive identification of neuropeptide precursors in crinoids. These include representatives of bilaterian neuropeptide precursor families and several predicted crinoid neuropeptide precursors. Using A. mediterranea as an experimental model, we have investigated the expression of selected neuropeptides in larvae (doliolaria), post-metamorphic pentacrinoids and adults, providing new insights into the cellular architecture of crinoid nervous systems. Thus, using mRNA in situ hybridization F-type SALMFamide precursor transcripts were revealed in a previously undescribed population of peptidergic cells located dorso-laterally in doliolaria. Furthermore, using immunohistochemistry a calcitonin-type neuropeptide was revealed in the aboral nerve center, circumoral nerve ring and oral tube feet in pentacrinoids and in the ectoneural and entoneural compartments of the nervous system in adults. Moreover, functional analysis of a vasopressin/oxytocin-type neuropeptide (crinotocin), which is expressed in the brachial nerve of the arms in A. mediterranea, revealed that this peptide causes a dose-dependent change in the mechanical behavior of arm preparations in vitro-the first reported biological action of a neuropeptide in a crinoid. In conclusion, our findings provide new perspectives on neuropeptide signaling in echinoderms and the foundations for further exploration of neuropeptide expression/function in crinoids as a sister clade to eleutherozoan echinoderms.
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Affiliation(s)
- Alessandra Aleotti
- Department of Environmental Science and Policy, University of Milan, Milan, Italy,School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Iain C. Wilkie
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Luis A. Yañez-Guerra
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Giacomo Gattoni
- Department of Environmental Science and Policy, University of Milan, Milan, Italy,School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Tahshin A. Rahman
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Richard F. Wademan
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Zakaryya Ahmad
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Deyana A. Ivanova
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Dean C. Semmens
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Jérôme Delroisse
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Weigang Cai
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Esther Odekunle
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Michaela Egertová
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Cinzia Ferrario
- Department of Environmental Science and Policy, University of Milan, Milan, Italy
| | - Michela Sugni
- Department of Environmental Science and Policy, University of Milan, Milan, Italy
| | - Francesco Bonasoro
- Department of Environmental Science and Policy, University of Milan, Milan, Italy
| | - Maurice R. Elphick
- School of Biological & Behavioural Sciences, Queen Mary University of London, London, United Kingdom,*Correspondence: Maurice R. Elphick,
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Tinoco AB, Barreiro-Iglesias A, Yañez Guerra LA, Delroisse J, Zhang Y, Gunner EF, Zampronio CG, Jones AM, Egertová M, Elphick MR. Ancient role of sulfakinin/cholecystokinin-type signalling in inhibitory regulation of feeding processes revealed in an echinoderm. eLife 2021; 10:e65667. [PMID: 34488941 PMCID: PMC8428848 DOI: 10.7554/elife.65667] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 08/18/2021] [Indexed: 01/04/2023] Open
Abstract
Sulfakinin (SK)/cholecystokinin (CCK)-type neuropeptides regulate feeding and digestion in protostomes (e.g. insects) and chordates. Here, we characterised SK/CCK-type signalling for the first time in a non-chordate deuterostome - the starfish Asterias rubens (phylum Echinodermata). In this species, two neuropeptides (ArSK/CCK1, ArSK/CCK2) derived from the precursor protein ArSK/CCKP act as ligands for an SK/CCK-type receptor (ArSK/CCKR) and these peptides/proteins are expressed in the nervous system, digestive system, tube feet, and body wall. Furthermore, ArSK/CCK1 and ArSK/CCK2 cause dose-dependent contraction of cardiac stomach, tube foot, and apical muscle preparations in vitro, and injection of these neuropeptides in vivo triggers cardiac stomach retraction and inhibition of the onset of feeding in A. rubens. Thus, an evolutionarily ancient role of SK/CCK-type neuropeptides as inhibitory regulators of feeding-related processes in the Bilateria has been conserved in the unusual and unique context of the extra-oral feeding behaviour and pentaradial body plan of an echinoderm.
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Affiliation(s)
- Ana B Tinoco
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | - Antón Barreiro-Iglesias
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | | | - Jérôme Delroisse
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | - Ya Zhang
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | - Elizabeth F Gunner
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics, Research Technology Platform, University of WarwickCoventryUnited Kingdom
| | - Alexandra M Jones
- School of Life Sciences and Proteomics, Research Technology Platform, University of WarwickCoventryUnited Kingdom
| | - Michaela Egertová
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Behavioural SciencesLondonUnited Kingdom
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Zhang Y, Yañez Guerra LA, Egertová M, Zampronio CG, Jones AM, Elphick MR. Molecular and functional characterization of somatostatin-type signalling in a deuterostome invertebrate. Open Biol 2020; 10:200172. [PMID: 32898470 PMCID: PMC7536072 DOI: 10.1098/rsob.200172] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Somatostatin (SS) and allatostatin-C (ASTC) are structurally and evolutionarily related neuropeptides that act as inhibitory regulators of physiological processes in mammals and insects, respectively. Here, we report the first molecular and functional characterization of SS/ASTC-type signalling in a deuterostome invertebrate—the starfish Asterias rubens (phylum Echinodermata). Two SS/ASTC-type precursors were identified in A. rubens (ArSSP1 and ArSSP2) and the structures of neuropeptides derived from these proteins (ArSS1 and ArSS2) were analysed using mass spectrometry. Pharmacological characterization of three cloned A. rubens SS/ASTC-type receptors (ArSSR1–3) revealed that ArSS2, but not ArSS1, acts as a ligand for all three receptors. Analysis of ArSS2 expression in A. rubens using mRNA in situ hybridization and immunohistochemistry revealed stained cells/fibres in the central nervous system, the digestive system (e.g. cardiac stomach) and the body wall and its appendages (e.g. tube feet). Furthermore, in vitro pharmacological tests revealed that ArSS2 causes dose-dependent relaxation of tube foot and cardiac stomach preparations, while injection of ArSS2 in vivo causes partial eversion of the cardiac stomach. Our findings provide new insights into the molecular evolution of SS/ASTC-type signalling in the animal kingdom and reveal an ancient role of SS-type neuropeptides as inhibitory regulators of muscle contractility.
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Affiliation(s)
- Ya Zhang
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | | | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry CV4 7AL, UK
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry CV4 7AL, UK
| | - Maurice R Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
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Odekunle EA, Semmens DC, Martynyuk N, Tinoco AB, Garewal AK, Patel RR, Blowes LM, Zandawala M, Delroisse J, Slade SE, Scrivens JH, Egertová M, Elphick MR. Ancient role of vasopressin/oxytocin-type neuropeptides as regulators of feeding revealed in an echinoderm. BMC Biol 2019; 17:60. [PMID: 31362737 PMCID: PMC6668147 DOI: 10.1186/s12915-019-0680-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Vasopressin/oxytocin (VP/OT)-type neuropeptides are well known for their roles as regulators of diuresis, reproductive physiology and social behaviour. However, our knowledge of their functions is largely based on findings from studies on vertebrates and selected protostomian invertebrates. Little is known about the roles of VP/OT-type neuropeptides in deuterostomian invertebrates, which are more closely related to vertebrates than protostomes. RESULTS Here, we have identified and functionally characterised a VP/OT-type signalling system comprising the neuropeptide asterotocin and its cognate G-protein coupled receptor in the starfish (sea star) Asterias rubens, a deuterostomian invertebrate belonging to the phylum Echinodermata. Analysis of the distribution of asterotocin and the asterotocin receptor in A. rubens using mRNA in situ hybridisation and immunohistochemistry revealed expression in the central nervous system (radial nerve cords and circumoral nerve ring), the digestive system (including the cardiac stomach) and the body wall and associated appendages. Informed by the anatomy of asterotocin signalling, in vitro pharmacological experiments revealed that asterotocin acts as a muscle relaxant in starfish, contrasting with the myotropic actions of VP/OT-type neuropeptides in vertebrates. Furthermore, in vivo injection of asterotocin had a striking effect on starfish behaviour-triggering fictive feeding where eversion of the cardiac stomach and changes in body posture resemble the unusual extra-oral feeding behaviour of starfish. CONCLUSIONS We provide a comprehensive characterisation of VP/OT-type signalling in an echinoderm, including a detailed anatomical analysis of the expression of both the VP/OT-type neuropeptide asterotocin and its cognate receptor. Our discovery that asterotocin triggers fictive feeding in starfish provides important new evidence of an evolutionarily ancient role of VP/OT-type neuropeptides as regulators of feeding in animals.
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Affiliation(s)
- Esther A. Odekunle
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Dean C. Semmens
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Nataly Martynyuk
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
- Department of Clinical Neurosciences, MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ UK
| | - Ana B. Tinoco
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Abdullah K. Garewal
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Radhika R. Patel
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Liisa M. Blowes
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Meet Zandawala
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
- Department of Neuroscience, Brown University, Providence, USA
| | - Jérôme Delroisse
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
- Research Institute for Biosciences, Biology of Marine Organisms and Biomimetics, University of Mons (UMONS), 7000 Mons, Belgium
| | - Susan E. Slade
- Waters/Warwick Centre for BioMedical Mass Spectrometry and Proteomics, School of Life Sciences, University of Warwick, Coventry, CV4 7AL UK
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow, SK9 4AX UK
| | - James H. Scrivens
- Waters/Warwick Centre for BioMedical Mass Spectrometry and Proteomics, School of Life Sciences, University of Warwick, Coventry, CV4 7AL UK
- School of Science, Engineering & Design, Teesside University, Stephenson Street, Tees Valley, TS1 3BA UK
| | - Michaela Egertová
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Maurice R. Elphick
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
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9
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Guan C, Egertová M, Perry CJ, Chittka L, Chittka A. Temporal correlation of elevated PRMT1 gene expression with mushroom body neurogenesis during bumblebee brain development. J Insect Physiol 2019; 116:57-69. [PMID: 31039373 DOI: 10.1016/j.jinsphys.2019.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/21/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Neural development depends on the controlled proliferation and differentiation of neural precursors. In holometabolous insects, these processes must be coordinated during larval and pupal development. Recently, protein arginine methylation has come into focus as an important mechanism of controlling neural stem cell proliferation and differentiation in mammals. Whether a similar mechanism is at work in insects is unknown. We investigated this possibility by determining the expression pattern of three protein arginine methyltransferase mRNAs (PRMT1, 4 and 5) in the developing brain of bumblebees by in situ hybridisation. We detected expression in neural precursors and neurons in functionally important brain areas throughout development. We found markedly higher expression of PRMT1, but not PRMT4 and PRMT5, in regions of mushroom bodies containing dividing cells during pupal stages at the time of active neurogenesis within this brain area. At later stages of development, PRMT1 expression levels were found to be uniform and did not correlate with actively dividing cells. Our study suggests a role for PRMT1 in regulating neural precursor divisions in the mushroom bodies of bumblebees during the period of neurogenesis.
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Affiliation(s)
- Cui Guan
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Clint J Perry
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lars Chittka
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Alexandra Chittka
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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Cai W, Kim CH, Go HJ, Egertová M, Zampronio CG, Jones AM, Park NG, Elphick MR. Biochemical, Anatomical, and Pharmacological Characterization of Calcitonin-Type Neuropeptides in Starfish: Discovery of an Ancient Role as Muscle Relaxants. Front Neurosci 2018; 12:382. [PMID: 29937709 PMCID: PMC6002491 DOI: 10.3389/fnins.2018.00382] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/18/2018] [Indexed: 11/16/2022] Open
Abstract
Calcitonin (CT) is a peptide hormone released by the thyroid gland that regulates blood Ca2+ levels in mammals. The CT gene is alternatively spliced, with one transcript encoding CT and another transcript encoding the CT-like neuropeptide calcitonin-gene related peptide (α-CGRP), which is a powerful vasodilator. Other CT-related peptides in vertebrates include adrenomedullin, amylin, and intermedin, which also act as smooth muscle relaxants. The evolutionary origin of CT-type peptides has been traced to the bilaterian common ancestor of protostomes and deuterostomes and a CT-like peptide (DH31) has been identified as a diuretic hormone in some insect species. However, little is known about the physiological roles of CT-type peptides in other invertebrates. Here we characterized a CT-type neuropeptide in a deuterostomian invertebrate—the starfish Asterias rubens (Phylum Echinodermata). A CT-type precursor cDNA (ArCTP) was sequenced and the predicted structure of the peptide (ArCT) derived from ArCTP was confirmed using mass spectrometry. The distribution of ArCTP mRNA and the ArCT peptide was investigated using in situ hybridization and immunohistochemistry, respectively, revealing stained cells/processes in the nervous system, digestive system, and muscular organs, including the apical muscle and tube feet. Investigation of the effects of synthetic ArCT on in vitro preparations of the apical muscle and tube feet revealed that it acts as a relaxant, causing dose-dependent reversal of acetylcholine-induced contraction. Furthermore, a muscle relaxant present in whole-animal extracts of another starfish species, Patiria pectinifera, was identified as an ortholog of ArCT and named PpCT. Consistent with the expression pattern of ArCTP in A. rubens, RT-qPCR revealed that in P. pectinifera the PpCT precursor transcript is more abundant in the radial nerve cords than in other tissues/organs analyzed. In conclusion, our findings indicate that the physiological action of CT-related peptides as muscle relaxants in vertebrates may reflect an evolutionarily ancient role of CT-type neuropeptides that can be traced back to the common ancestor of deuterostomes.
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Affiliation(s)
- Weigang Cai
- School of Biological & Chemical Sciences Queen Mary University of London, London, United Kingdom
| | - Chan-Hee Kim
- Department of Biotechnology, College of Fisheries Sciences Pukyong National University, Busan, South Korea
| | - Hye-Jin Go
- Department of Biotechnology, College of Fisheries Sciences Pukyong National University, Busan, South Korea
| | - Michaela Egertová
- School of Biological & Chemical Sciences Queen Mary University of London, London, United Kingdom
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform University of Warwick, Coventry, United Kingdom
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform University of Warwick, Coventry, United Kingdom
| | - Nam Gyu Park
- Department of Biotechnology, College of Fisheries Sciences Pukyong National University, Busan, South Korea
| | - Maurice R Elphick
- School of Biological & Chemical Sciences Queen Mary University of London, London, United Kingdom
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11
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Li L, MaBouDi H, Egertová M, Elphick MR, Chittka L, Perry CJ. A possible structural correlate of learning performance on a colour discrimination task in the brain of the bumblebee. Proc Biol Sci 2018; 284:rspb.2017.1323. [PMID: 28978727 PMCID: PMC5647297 DOI: 10.1098/rspb.2017.1323] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/21/2017] [Indexed: 12/02/2022] Open
Abstract
Synaptic plasticity is considered to be a basis for learning and memory. However, the relationship between synaptic arrangements and individual differences in learning and memory is poorly understood. Here, we explored how the density of microglomeruli (synaptic complexes) within specific regions of the bumblebee (Bombus terrestris) brain relates to both visual learning and inter-individual differences in learning and memory performance on a visual discrimination task. Using whole-brain immunolabelling, we measured the density of microglomeruli in the collar region (visual association areas) of the mushroom bodies of the bumblebee brain. We found that bumblebees which made fewer errors during training in a visual discrimination task had higher microglomerular density. Similarly, bumblebees that had better retention of the learned colour-reward associations two days after training had higher microglomerular density. Further experiments indicated experience-dependent changes in neural circuitry: learning a colour-reward contingency with 10 colours (but not two colours) does result, and exposure to many different colours may result, in changes to microglomerular density in the collar region of the mushroom bodies. These results reveal the varying roles that visual experience, visual learning and foraging activity have on neural structure. Although our study does not provide a causal link between microglomerular density and performance, the observed positive correlations provide new insights for future studies into how neural structure may relate to inter-individual differences in learning and memory.
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Affiliation(s)
- Li Li
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - HaDi MaBouDi
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Maurice R Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Lars Chittka
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Clint J Perry
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
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12
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Tinoco AB, Semmens DC, Patching EC, Gunner EF, Egertová M, Elphick MR. Characterization of NGFFYamide Signaling in Starfish Reveals Roles in Regulation of Feeding Behavior and Locomotory Systems. Front Endocrinol (Lausanne) 2018; 9:507. [PMID: 30283399 PMCID: PMC6156427 DOI: 10.3389/fendo.2018.00507] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/14/2018] [Indexed: 12/12/2022] Open
Abstract
Neuropeptides in deuterostomian invertebrates that have an Asn-Gly motif (NG peptides) have been identified as orthologs of vertebrate neuropeptide-S (NPS)-type peptides and protostomian crustacean cardioactive peptide (CCAP)-type neuropeptides. To obtain new insights into the physiological roles of NG peptides in deuterostomian invertebrates, here we have characterized the NG peptide signaling system in an echinoderm-the starfish Asterias rubens. The neuropeptide NGFFYamide was identified as the ligand for an A. rubens NPS/CCAP-type receptor, providing further confirmation that NG peptides are orthologs of NPS/CCAP-type neuropeptides. Using mRNA in situ hybridization, cells expressing the NGFFYamide precursor transcript were revealed in the radial nerve cords, circumoral nerve ring, coelomic epithelium, apical muscle, body wall, stomach, and tube feet of A. rubens, indicating that NGFFYamide may have a variety of physiological roles in starfish. One of the most remarkable aspects of starfish biology is their feeding behavior, where the stomach is everted out of the mouth over the soft tissue of prey. Previously, we reported that NGFFYamide triggers retraction of the everted stomach in A. rubens and here we show that in vivo injection of NGFFYamide causes a significant delay in the onset of feeding on prey. To investigate roles in regulating other aspects of starfish physiology, we examined the in vitro effects of NGFFYamide and found that it causes relaxation of acetylcholine-contracted apical muscle preparations and induction of tonic and phasic contraction of tube feet. Furthermore, analysis of the effects of in vivo injection of NGFFYamide on starfish locomotor activity revealed that it causes a significant reduction in mean velocity and distance traveled. Interestingly, experimental studies on mammals have revealed that NPS is an anxiolytic that suppresses appetite and induces hyperactivity in mammals. Our characterization of the actions of NGFFYamide in starfish indicates that NPS/NG peptide/CCAP-type signaling is an evolutionarily ancient regulator of feeding and locomotion.
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13
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Lin M, Egertová M, Zampronio CG, Jones AM, Elphick MR. Functional characterization of a second pedal peptide/orcokinin-type neuropeptide signaling system in the starfish Asterias rubens. J Comp Neurol 2017; 526:858-876. [PMID: 29218721 PMCID: PMC5814872 DOI: 10.1002/cne.24371] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/27/2022]
Abstract
Molluscan pedal peptides (PPs) and arthropod orcokinins (OKs) are prototypes of a family of neuropeptides that have been identified in several phyla. Recently, starfish myorelaxant peptide (SMP) was identified as a PP/OK‐type neuropeptide in the starfish Patiria pectinifera (phylum Echinodermata). Furthermore, analysis of transcriptome sequence data from the starfish Asterias rubens revealed two PP/OK‐type precursors: an SMP‐type precursor (A. rubens PP‐like neuropeptide precursor 1; ArPPLNP1) and a second precursor (ArPPLNP2). We reported previously a detailed analysis of ArPPLNP1 expression in A. rubens and here we report the first functional characterization ArPPLNP2‐derived neuropeptides. Sequencing of a cDNA encoding ArPPLNP2 revealed that it comprises eleven related neuropeptides (ArPPLN2a‐k), the structures of several of which were confirmed using mass spectrometry. Analysis of the expression of ArPPLNP2 and neuropeptides derived from this precursor using mRNA in situ hybridization and immunohistochemistry revealed a widespread distribution, including expression in radial nerve cords, circumoral nerve ring, digestive system, tube feet and innervation of interossicular muscles. In vitro pharmacology revealed that the ArPPLNP2‐derived neuropeptide ArPPLN2h has no effect on the contractility of tube feet or the body wall‐associated apical muscle, contrasting with the relaxing effect of ArPPLN1b (ArSMP) on these preparations. ArPPLN2h does, however, cause dose‐dependent relaxation of cardiac stomach preparations, with greater potency/efficacy than ArPPLN1b and with similar potency/efficacy to the SALMFamide neuropeptide S2. In conclusion, there are similarities in the expression patterns of ArPPLNP1 and ArPPLNP2 but our data also indicate specialization in the roles of neuropeptides derived from these two PP/OK‐type precursors in starfish.
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Affiliation(s)
- Ming Lin
- School of Biological & Chemical Sciences, Mile End Road, Queen Mary University of London, London, United Kingdom
| | - Michaela Egertová
- School of Biological & Chemical Sciences, Mile End Road, Queen Mary University of London, London, United Kingdom
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, United Kingdom
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, United Kingdom
| | - Maurice R Elphick
- School of Biological & Chemical Sciences, Mile End Road, Queen Mary University of London, London, United Kingdom
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14
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Lin M, Egertová M, Zampronio CG, Jones AM, Elphick MR. Pedal peptide/orcokinin-type neuropeptide signaling in a deuterostome: The anatomy and pharmacology of starfish myorelaxant peptide in Asterias rubens. J Comp Neurol 2017; 525:3890-3917. [PMID: 28880392 PMCID: PMC5656890 DOI: 10.1002/cne.24309] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/15/2017] [Accepted: 08/23/2017] [Indexed: 12/11/2022]
Abstract
Pedal peptide (PP) and orcokinin (OK) are related neuropeptides that were discovered in protostomian invertebrates (mollusks, arthropods). However, analysis of genome/transcriptome sequence data has revealed that PP/OK‐type neuropeptides also occur in a deuterostomian phylum—the echinoderms. Furthermore, a PP/OK‐type neuropeptide (starfish myorelaxant peptide, SMP) was recently identified as a muscle relaxant in the starfish Patiria pectinifera. Here mass spectrometry was used to identify five neuropeptides (ArPPLN1a‐e) derived from the SMP precursor (PP‐like neuropeptide precursor 1; ArPPLNP1) in the starfish Asterias rubens. Analysis of the expression of ArPPLNP1 and neuropeptides derived from this precursor in A. rubens using mRNA in situ hybridization and immunohistochemistry revealed a widespread pattern of expression, with labeled cells and/or processes present in the radial nerve cords, circumoral nerve ring, digestive system (e.g., cardiac stomach) and body wall‐associated muscles (e.g., apical muscle) and appendages (e.g., tube feet and papulae). Furthermore, our data provide the first evidence that neuropeptides are present in the lateral motor nerves and in nerve processes innervating interossicular muscles. In vitro pharmacological tests with SMP (ArPPLN1b) revealed that it causes dose‐dependent relaxation of apical muscle, tube foot and cardiac stomach preparations from A. rubens. Collectively, these anatomical and pharmacological data indicate that neuropeptides derived from ArPPLNP1 act as inhibitory neuromuscular transmitters in starfish, which contrasts with the myoexcitatory actions of PP/OK‐type neuropeptides in protostomian invertebrates. Thus, the divergence of deuterostomes and protostomes may have been accompanied by an inhibitory–excitatory transition in the roles of PP/OK‐type neuropeptides as regulators of muscle activity.
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Affiliation(s)
- Ming Lin
- Queen Mary University of London, School of Biological & Chemical Sciences, Mile End Road, London, UK
| | - Michaela Egertová
- Queen Mary University of London, School of Biological & Chemical Sciences, Mile End Road, London, UK
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Chemical Sciences, Mile End Road, London, UK
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15
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Abstract
The body wall of starfish is composed of magnesium calcite ossicles connected by collagenous tissue and muscles and it exhibits remarkable variability in stiffness, which is attributed to the mechanical mutability of the collagenous component. Using the common European starfish Asterias rubens as an experimental animal, here we have employed a variety of techniques to gain new insights into the structure of the starfish body wall. The structure and organisation of muscular and collagenous components of the body wall were analysed using trichrome staining. The muscle system comprises interossicular muscles as well as muscle strands that connect ossicles with the circular muscle layer of the coelomic lining. The collagenous tissue surrounding the ossicle network contains collagen fibres that form loop-shaped straps that wrap around calcite struts near to the surface of ossicles. The 3D architecture of the calcareous endoskeleton was visualised for the first time using X-ray microtomography, revealing the shapes and interactions of different ossicle types. Furthermore, analysis of the anatomical organisation of the ossicles indicates how changes in body shape may be achieved by local contraction/relaxation of interossicular muscles. Scanning synchrotron small-angle X-ray diffraction (SAXD) scans of the starfish aboral body wall and ambulacrum were used to study the collagenous tissue component at the fibrillar level. Collagen fibrils in aboral body wall were found to exhibit variable degrees of alignment, with high levels of alignment probably corresponding to regions where collagenous tissue is under tension. Collagen fibrils in the ambulacrum had a uniformly low degree of orientation, attributed to macrocrimp of the fibrils and the presence of slanted as well as horizontal fibrils connecting antimeric ambulacral ossicles. Body wall collagen fibril D-period lengths were similar to previously reported mammalian D-periods, but were significantly different between the aboral and ambulacral samples. The overlap/D-period length ratio within fibrils was higher than reported for mammalian tissues. Collectively, the data reported here provide new insights into the anatomy of the body wall in A. rubens and a foundation for further studies investigating the structural basis of the mechanical properties of echinoderm body wall tissue composites.
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Affiliation(s)
- Liisa M Blowes
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK.,School of Engineering & Materials Science, Queen Mary University of London, London, UK
| | - Michaela Egertová
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
| | - Yankai Liu
- School of Engineering & Materials Science, Queen Mary University of London, London, UK
| | - Graham R Davis
- Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - Himadri S Gupta
- School of Engineering & Materials Science, Queen Mary University of London, London, UK
| | - Maurice R Elphick
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
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16
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Tian S, Egertová M, Elphick MR. Functional Characterization of Paralogous Gonadotropin-Releasing Hormone-Type and Corazonin-Type Neuropeptides in an Echinoderm. Front Endocrinol (Lausanne) 2017; 8:259. [PMID: 29033898 PMCID: PMC5626854 DOI: 10.3389/fendo.2017.00259] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 09/20/2017] [Indexed: 12/12/2022] Open
Abstract
Homologs of the vertebrate neuropeptide gonadotropin-releasing hormone (GnRH) have been identified in invertebrates, including the insect neuropeptide corazonin (CRZ). Recently, we reported the discovery of GnRH-type and CRZ-type signaling systems in an echinoderm, the starfish Asterias rubens, demonstrating that the evolutionary origin of paralogous GnRH-type and CRZ-type neuropeptides can be traced back to the common ancestor of protostomes and deuterostomes. Here, we have investigated the physiological roles of the GnRH-type (ArGnRH) and the CRZ-type (ArCRZ) neuropeptides in A. rubens, using mRNA in situ hybridization, immunohistochemistry and in vitro pharmacology. ArGnRH precursor (ArGnRHP)-expressing cells and ArGnRH-immunoreactive cells and/or processes are present in the radial nerve cords, circumoral nerve ring, digestive system (e.g., cardiac stomach and pyloric stomach), body wall-associated muscle (apical muscle), and appendages (tube feet, terminal tentacle). The general distribution of ArCRZ precursor (ArCRZP)-expressing cells is similar to that of ArGnRHP, but with specific local differences. For example, cells expressing ArGnRHP are present in both the ectoneural and hyponeural regions of the radial nerve cords and circumoral nerve ring, whereas cells expressing ArCRZP were only observed in the ectoneural region. In vitro pharmacological experiments revealed that both ArGnRH and ArCRZ cause contraction of cardiac stomach, apical muscle, and tube foot preparations. However, ArGnRH was more potent/effective than ArCRZ as a contractant of the cardiac stomach, whereas ArCRZ was more potent/effective than ArGnRH as a contractant of the apical muscle. These findings demonstrate that both ArGnRH and ArCRZ are myoexcitatory neuropeptides in starfish, but differences in their expression patterns and pharmacological activities are indicative of distinct physiological roles. This is the first study to investigate the physiological roles of both GnRH-type and CRZ-type neuropeptides in a deuterostome, providing new insights into the evolution and comparative physiology of these paralogous neuropeptide signaling systems in the Bilateria.
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Affiliation(s)
- Shi Tian
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Maurice R. Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- *Correspondence: Maurice R. Elphick,
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17
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Mayorova TD, Tian S, Cai W, Semmens DC, Odekunle EA, Zandawala M, Badi Y, Rowe ML, Egertová M, Elphick MR. Localization of Neuropeptide Gene Expression in Larvae of an Echinoderm, the Starfish Asterias rubens. Front Neurosci 2016; 10:553. [PMID: 27990106 PMCID: PMC5130983 DOI: 10.3389/fnins.2016.00553] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/16/2016] [Indexed: 11/13/2022] Open
Abstract
Neuropeptides are an ancient class of neuronal signaling molecules that regulate a variety of physiological and behavioral processes in animals. The life cycle of many animals includes a larval stage(s) that precedes metamorphic transition to a reproductively active adult stage but, with the exception of Drosophila melanogaster and other insects, research on neuropeptide signaling has hitherto largely focused on adult animals. However, recent advances in genome/transcriptome sequencing have facilitated investigation of neuropeptide expression/function in the larvae of protostomian (e.g., the annelid Platynereis dumerilii) and deuterostomian (e.g., the urochordate Ciona intestinalis) invertebrates. Accordingly, here we report the first multi-gene investigation of larval neuropeptide precursor expression in a species belonging to the phylum Echinodermata-the starfish Asterias rubens. Whole-mount mRNA in situ hybridization was used to visualize in bipinnaria and brachiolaria stage larvae the expression of eight neuropeptide precursors: L-type SALMFamide (S1), F-type SALMFamide (S2), vasopressin/oxytocin-type, NGFFYamide, thyrotropin-releasing hormone-type, gonadotropin-releasing hormone-type, calcitonin-type and corticotropin-releasing hormone-type. Expression of only three of the precursors (S1, S2, NGFFYamide) was observed in bipinnaria larvae but by the brachiolaria stage expression of all eight precursors was detected. An evolutionarily conserved feature of larval nervous systems is the apical organ and in starfish larvae this comprises the bilaterally symmetrical lateral ganglia, but only the S1 and S2 precursors were found to be expressed in these ganglia. A prominent feature of brachiolaria larvae is the attachment complex, comprising the brachia and adhesive disk, which mediates larval attachment to a substratum prior to metamorphosis. Interestingly, all of the neuropeptide precursors examined here are expressed in the attachment complex, with distinctive patterns of expression suggesting potential roles for neuropeptides in the attachment process. Lastly, expression of several neuropeptide precursors is associated with ciliary bands, suggesting potential roles for the neuropeptides derived from these precursors in control of larval locomotion and/or feeding. In conclusion, our findings provide novel perspectives on the evolution and development of neuropeptide signaling systems and neuroanatomical insights into neuropeptide function in echinoderm larvae.
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Affiliation(s)
- Tatiana D Mayorova
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of LondonLondon, UK; Laboratory of Developmental Neurobiology, Koltzov Institute of Developmental Biology of Russian Academy of SciencesMoscow, Russia
| | - Shi Tian
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Weigang Cai
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Dean C Semmens
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Esther A Odekunle
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Meet Zandawala
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Yusef Badi
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Matthew L Rowe
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Michaela Egertová
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
| | - Maurice R Elphick
- Department of Organismal Biology, School of Biological and Chemical Sciences, Queen Mary University of London London, UK
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18
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Lin M, Mita M, Egertová M, Zampronio CG, Jones AM, Elphick MR. Cellular localization of relaxin-like gonad-stimulating peptide expression in Asterias rubens: New insights into neurohormonal control of spawning in starfish. J Comp Neurol 2016; 525:1599-1617. [PMID: 27806429 PMCID: PMC5396301 DOI: 10.1002/cne.24141] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 02/04/2023]
Abstract
Gamete maturation and spawning in starfish is triggered by a gonad-stimulating substance (GSS), which is present in extracts of the radial nerve cords. Purification of GSS from the starfish Patiria pectinifera identified GSS as a relaxin-like polypeptide, which is now known as relaxin-like gonad-stimulating peptide (RGP). Cells expressing RGP in the radial nerve cord of P. pectinifera have been visualized, but the presence of RGP-expressing cells in other parts of the starfish body has not been investigated. Here we addressed this issue in the starfish Asterias rubens. An A. rubens RGP (AruRGP) precursor cDNA was sequenced and the A chain and B chain that form AruRGP were detected in A. rubens radial nerve cord extracts using mass spectrometry. Comparison of the bioactivity of AruRGP and P. pectinifera RGP (PpeRGP) revealed that both polypeptides induce oocyte maturation and ovulation in A. rubens ovarian fragments, but AruRGP is more potent than PpeRGP. Analysis of the expression of AruRGP in A. rubens using mRNA in situ hybridization revealed cells expressing RGP in the radial nerve cords, circumoral nerve ring, and tube feet. Furthermore, a band of RGP-expressing cells was identified in the body wall epithelium lining the cavity that surrounds the sensory terminal tentacle and optic cushion at the tips of the arms. Discovery of these RGP-expressing cells closely associated with sensory organs in the arm tips is an important finding because these cells are candidate physiological mediators for hormonal control of starfish spawning in response to environmental cues. J. Comp. Neurol. 525:1599-1617, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ming Lin
- Queen Mary University of London, School of Biological & Chemical Sciences, London, UK
| | - Masatoshi Mita
- Department of Biology, Faculty of Education, Tokyo Gakugei University, Tokyo, Japan
| | - Michaela Egertová
- Queen Mary University of London, School of Biological & Chemical Sciences, London, UK
| | - Cleidiane G Zampronio
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Alexandra M Jones
- School of Life Sciences and Proteomics Research Technology Platform, University of Warwick, Coventry, UK
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Chemical Sciences, London, UK
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19
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Mo J, Prévost SF, Blowes LM, Egertová M, Terrill NJ, Wang W, Elphick MR, Gupta HS. Interfibrillar stiffening of echinoderm mutable collagenous tissue demonstrated at the nanoscale. Proc Natl Acad Sci U S A 2016; 113:E6362-E6371. [PMID: 27708167 PMCID: PMC5081653 DOI: 10.1073/pnas.1609341113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mutable collagenous tissue (MCT) of echinoderms (e.g., sea cucumbers and starfish) is a remarkable example of a biological material that has the unique attribute, among collagenous tissues, of being able to rapidly change its stiffness and extensibility under neural control. However, the mechanisms of MCT have not been characterized at the nanoscale. Using synchrotron small-angle X-ray diffraction to probe time-dependent changes in fibrillar structure during in situ tensile testing of sea cucumber dermis, we investigate the ultrastructural mechanics of MCT by measuring fibril strain at different chemically induced mechanical states. By measuring a variable interfibrillar stiffness (EIF), the mechanism of mutability at the nanoscale can be demonstrated directly. A model of stiffness modulation via enhanced fibrillar recruitment is developed to explain the biophysical mechanisms of MCT. Understanding the mechanisms of MCT quantitatively may have applications in development of new types of mechanically tunable biomaterials.
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Affiliation(s)
- Jingyi Mo
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Sylvain F Prévost
- Beamline ID02, European Synchrotron Radiation Facility, Grenoble 38000, France
| | - Liisa M Blowes
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Nicholas J Terrill
- Beamline I22, Diamond Light Source, Harwell Science and Innovation Campus, Harwell, OX11 0DE, United Kingdom
| | - Wen Wang
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom; Institute of Bioengineering, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Maurice R Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom;
| | - Himadri S Gupta
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom; Institute of Bioengineering, Queen Mary University of London, London, E1 4NS, United Kingdom
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Smith TH, Blume LC, Straiker A, Cox JO, David BG, McVoy JRS, Sayers KW, Poklis JL, Abdullah RA, Egertová M, Chen CK, Mackie K, Elphick MR, Howlett AC, Selley DE. Cannabinoid receptor-interacting protein 1a modulates CB1 receptor signaling and regulation. Mol Pharmacol 2015; 87:747-65. [PMID: 25657338 DOI: 10.1124/mol.114.096495] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cannabinoid CB1 receptors (CB1Rs) mediate the presynaptic effects of endocannabinoids in the central nervous system (CNS) and most behavioral effects of exogenous cannabinoids. Cannabinoid receptor-interacting protein 1a (CRIP1a) binds to the CB1R C-terminus and can attenuate constitutive CB1R-mediated inhibition of Ca(2+) channel activity. We now demonstrate cellular colocalization of CRIP1a at neuronal elements in the CNS and show that CRIP1a inhibits both constitutive and agonist-stimulated CB1R-mediated guanine nucleotide-binding regulatory protein (G-protein) activity. Stable overexpression of CRIP1a in human embryonic kidney (HEK)-293 cells stably expressing CB1Rs (CB1-HEK), or in N18TG2 cells endogenously expressing CB1Rs, decreased CB1R-mediated G-protein activation (measured by agonist-stimulated [(35)S]GTPγS (guanylyl-5'-[O-thio]-triphosphate) binding) in both cell lines and attenuated inverse agonism by rimonabant in CB1-HEK cells. Conversely, small-interfering RNA-mediated knockdown of CRIP1a in N18TG2 cells enhanced CB1R-mediated G-protein activation. These effects were not attributable to differences in CB1R expression or endocannabinoid tone because CB1R levels did not differ between cell lines varying in CRIP1a expression, and endocannabinoid levels were undetectable (CB1-HEK) or unchanged (N18TG2) by CRIP1a overexpression. In CB1-HEK cells, 4-hour pretreatment with cannabinoid agonists downregulated CB1Rs and desensitized agonist-stimulated [(35)S]GTPγS binding. CRIP1a overexpression attenuated CB1R downregulation without altering CB1R desensitization. Finally, in cultured autaptic hippocampal neurons, CRIP1a overexpression attenuated both depolarization-induced suppression of excitation and inhibition of excitatory synaptic activity induced by exogenous application of cannabinoid but not by adenosine A1 agonists. These results confirm that CRIP1a inhibits constitutive CB1R activity and demonstrate that CRIP1a can also inhibit agonist-stimulated CB1R signaling and downregulation of CB1Rs. Thus, CRIP1a appears to act as a broad negative regulator of CB1R function.
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Affiliation(s)
- Tricia H Smith
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Lawrence C Blume
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Alex Straiker
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Jordan O Cox
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Bethany G David
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Julie R Secor McVoy
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Katherine W Sayers
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Justin L Poklis
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Rehab A Abdullah
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Michaela Egertová
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Ching-Kang Chen
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Ken Mackie
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Maurice R Elphick
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Allyn C Howlett
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
| | - Dana E Selley
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies (T.H.S., J.O.C., B.G.D., J.R.S.M., J.L.P., R.A.A., D.E.S.), Department of Anatomy and Neurobiology (K.W.S.), Department of Biochemistry and Molecular Biology (C.-K.C.), Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina (L.C.B., A.C.H.); The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana (A.S., K.M.); and School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom (M.E., M.R.E.)
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Stauffer B, Wallis KT, Wilson SP, Egertová M, Elphick MR, Lewis DL, Hardy LR. CRIP1a switches cannabinoid receptor agonist/antagonist-mediated protection from glutamate excitotoxicity. Neurosci Lett 2011; 503:224-8. [PMID: 21896317 DOI: 10.1016/j.neulet.2011.08.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 08/02/2011] [Accepted: 08/22/2011] [Indexed: 10/17/2022]
Abstract
A shared pathology among many neurological and neurodegenerative disorders is neuronal loss. Cannabinoids have been shown to be neuroprotective in multiple systems. However, both agonists and antagonists of the CB(1) cannabinoid receptor are neuroprotective, but the mechanisms responsible for these actions remain unclear. Recently a CB(1) receptor interacting protein, CRIP1a, was identified and found to alter CB(1) activity. Here we show that in an assay of glutamate neurotoxicity in primary neuronal cortical cultures CRIP1a disrupts agonist-induced neuroprotection and confers antagonist-induced neuroprotection.
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Affiliation(s)
- Brandon Stauffer
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Health Sciences University, Augusta, GA 30912, USA
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22
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23
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Liu L, Heneghan JF, Michael GJ, Stanish LF, Egertová M, Rittenhouse AR. L- and N-current but not M-current inhibition by M1 muscarinic receptors requires DAG lipase activity. J Cell Physiol 2008; 216:91-100. [PMID: 18247369 DOI: 10.1002/jcp.21378] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Stimulation of postsynaptic M(1) muscarinic receptors (M(1)Rs) increases firing rates of both sympathetic and central neurons that underlie increases in vasomotor tone, heart rate, and cognitive memory functioning. At the cellular level, M(1)R stimulation modulates currents through various voltage-gated ion channels, including KCNQ K+ channels (M-current) and both L- and N-type Ca2+ channels (L- and N-current) by a pertussis toxin-insensitive, slow signaling pathway. Depletion of phosphatidylinositol-4,5-bisphosphate (PIP2) during M(1)R stimulation suffices to inhibit M-current. We found previously that following PIP2 hydrolysis by phospholipase C, activation of phospholipase A2 and liberation of a lipid metabolite, most likely arachidonic acid (AA) are necessary for L- and N-current modulation. Here we examined the involvement of a third lipase, diacylglycerol lipase (DAGL), in the slow pathway. We documented the presence of DAGL in superior cervical ganglion neurons, and then tested the highly selective DAGL inhibitor, RHC-80267, for its capacity to antagonize M(1)R-mediated modulation of whole-cell Ca2+ currents. RHC-80267 significantly reduced L- and N-current inhibition by the muscarinic agonist oxotremorine-M (Oxo-M) but did not affect their inhibition by exogenous AA. Moreover, voltage-dependent inhibition of N-current by Oxo-M remained in the presence of RHC-80267, indicating selective action on the slow pathway. RHC also blocked inhibition of recombinant N-current. In contrast, RHC-80267 had no effect on native M-current inhibition. These data are consistent with a role for DAGL in mediating L- and N-current inhibition. These results extend our previous findings that the signaling pathway mediating L- and N-current inhibition diverges from the pathway initiating M-current inhibition.
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Affiliation(s)
- Liwang Liu
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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24
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Cooray SN, Almiro Do Vale I, Leung KY, Webb TR, Chapple JP, Egertová M, Cheetham ME, Elphick MR, Clark AJL. The melanocortin 2 receptor accessory protein exists as a homodimer and is essential for the function of the melanocortin 2 receptor in the mouse y1 cell line. Endocrinology 2008; 149:1935-41. [PMID: 18162519 DOI: 10.1210/en.2007-1463] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The ACTH receptor [melanocortin 2 receptor (MC2R)] gene produces a functional receptor only when transfected into cells of adrenocortical origin, implying that it may require an adrenal-specific accessory factor. Recently we showed that the MC2R accessory protein (MRAP) is essential for the cell surface expression of the MC2R in such models. Using RNA interference (RNAi) technology, we have further explored the action of MRAP in the functioning of the MC2R in Y1 mouse adrenocortical cells that endogenously express MRAP and MC2R. We created stable cell lines expressing mouse MRAP short hairpin RNA (shRNAs) by transfecting cells with an expression vector containing the MRAP small interfering RNA sequence. The knockdown of MRAP resulted in a reduction in MC2R signaling. The overexpression of a mouse MRAP-Flag construct did not restore the expression of MRAP due to its degradation by the mouse shRNAs. The introduction of human MRAP that is resistant to silencing by mouse MRAP shRNAs resulted in the rescue of the MC2R signaling. MRAP migrates on SDS-PAGE with markedly lower mobility than predicted for a 14.1-kDa protein. Coimmunoprecipitation and mass spectroscopy suggests that MRAP exists as a homodimer that is resistant to dissociation by sodium dodecyl sulfate and reducing agents.
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Affiliation(s)
- Sadani N Cooray
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London, Queen Mary University of London, West Smithfield, London, United Kingdom
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25
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Egertová M, Simon GM, Cravatt BF, Elphick MR. Localization of N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) expression in mouse brain: A new perspective on N-acylethanolamines as neural signaling molecules. J Comp Neurol 2008; 506:604-15. [PMID: 18067139 DOI: 10.1002/cne.21568] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
N-acylethanolamines (NAEs) are membrane-derived lipids that are utilized as signaling molecules in the nervous system (e.g., the endocannabinoid anandamide). An N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) that catalyzes formation of NAEs was recently identified as a member of the zinc metallohydrolase family of enzymes. NAPE-PLD(-/-) mice have greatly reduced brain levels of long-chain saturated NAEs but wild-type levels of polyunsaturated NAEs (e.g., anandamide), suggesting an important role for NAPE-PLD in the biosynthesis of at least a subset of endogenous NAEs in the mammalian nervous system. To provide a neuroanatomical basis for investigation of NAPE-PLD function, here we have analyzed expression of NAPE-PLD in the mouse brain using mRNA in situ hybridization and immunocytochemistry. NAPE-PLD(-/-) mice were utilized to establish the specificity of probes/antibodies used. The most striking feature of NAPE-PLD expression in the brain was in the dentate gyrus, where a strong mRNA signal was detected in granule cells. Accordingly, immunocytochemical analysis revealed intense NAPE-PLD immunoreactivity in the axons of granule cells (mossy fibers). Intense NAPE-PLD immunoreactivity was also detected in axons of the vomeronasal nerve that project to the accessory olfactory bulb. NAPE-PLD expression was detected in other brain regions (e.g., hippocampus, cortex, thalamus, hypothalamus), but the intensity of immunostaining was weaker than in mossy fibers. Collectively, the data obtained indicate that NAPE-PLD is expressed by specific populations of neurons in the brain and targeted to axonal processes. We suggest that NAEs generated by NAPE-PLD in axons may act as anterograde synaptic signaling molecules that regulate the activity of postsynaptic neurons.
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Affiliation(s)
- Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, United Kingdom
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Niehaus JL, Liu Y, Wallis KT, Egertová M, Bhartur SG, Mukhopadhyay S, Shi S, He H, Selley DE, Howlett AC, Elphick MR, Lewis DL. CB1 Cannabinoid Receptor Activity Is Modulated by the Cannabinoid Receptor Interacting Protein CRIP 1a. Mol Pharmacol 2007; 72:1557-66. [PMID: 17895407 DOI: 10.1124/mol.107.039263] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The CB1 cannabinoid receptor is a G-protein coupled receptor that has important physiological roles in synaptic plasticity, analgesia, appetite, and neuroprotection. We report the discovery of two structurally related CB1 cannabinoid receptor interacting proteins (CRIP1a and CRIP1b) that bind to the distal C-terminal tail of CB1. CRIP1a and CRIP1b are generated by alternative splicing of a gene located on chromosome 2 in humans, and orthologs of CRIP1a occur throughout the vertebrates, whereas CRIP1b seems to be unique to primates. CRIP1a coimmunoprecipitates with CB1 receptors derived from rat brain homogenates, indicating that CRIP1a and CB1 interact in vivo. Furthermore, in superior cervical ganglion neurons coinjected with CB1 and CRIP1a or CRIP1b cDNA, CRIP1a, but not CRIP1b, suppresses CB1-mediated tonic inhibition of voltage-gated Ca2+ channels. Discovery of CRIP1a provides the basis for a new avenue of research on mechanisms of CB1 regulation in the nervous system and may lead to development of novel drugs to treat disorders where modulation of CB1 activity has therapeutic potential (e.g., chronic pain, obesity, and epilepsy).
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Affiliation(s)
- Jason L Niehaus
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA
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Egertová M, Elphick MR. Localization of CiCBR in the invertebrate chordate Ciona intestinalis: evidence of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. J Comp Neurol 2007; 502:660-72. [PMID: 17428001 DOI: 10.1002/cne.21331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
CiCBR is a G-protein-coupled receptor in the sea-squirt Ciona intestinalis and the first ortholog of vertebrate CB(1) and CB(2) cannabinoid receptors to be identified in an invertebrate (Elphick et al. [2003] Gene 302:95-101). Here we have used Western blotting and immunocytochemistry to examine expression of CiCBR in adult Ciona, employing novel antibodies to the C-terminal tail of CiCBR. Consistent with the expected mass for CiCBR, a approximately 47-kDa band was detected in Ciona membranes, and immunocytochemical analysis of serial sections of Ciona revealed intense immunoreactivity in the cerebral ganglion localised in a dense meshwork of fibers in the neuropile. Accordingly, Western blot analysis of neural complex homogenates revealed the presence of a approximately 47-kDa band. CiCBR immunoreactivity was also observed in axons exiting the ganglion in the anterior and posterior nerves, and analysis of whole-mount preparations revealed that these axons project over the interior surface of the oral and atrial siphons. Isolated CiCBR-immunoreactive axons not associated with the anterior and posterior nerves were observed projecting through the cortical layer of the cerebral ganglion. Central and peripheral CiCBR-immunoreactive fibers were studded with intensely stained varicosities, indicative of a role for CiCBR in regulation of axonal release of neurotransmitters, neuromodulators, or neurohormones. Collectively, our data suggest that the well-established role that the CB(1) receptor has as an axonal regulator of neurotransmitter release in mammals may have originated with ancestral-type cannabinoid receptors in invertebrate chordates before the emergence of CB(1)- and CB(2)-type receptors in vertebrates.
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Affiliation(s)
- Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, United Kingdom
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28
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Monory K, Massa F, Egertová M, Eder M, Blaudzun H, Westenbroek R, Kelsch W, Jacob W, Marsch R, Ekker M, Long J, Rubenstein JL, Goebbels S, Nave KA, During M, Klugmann M, Wölfel B, Dodt HU, Zieglgänsberger W, Wotjak CT, Mackie K, Elphick MR, Marsicano G, Lutz B. The endocannabinoid system controls key epileptogenic circuits in the hippocampus. Neuron 2006; 51:455-66. [PMID: 16908411 PMCID: PMC1769341 DOI: 10.1016/j.neuron.2006.07.006] [Citation(s) in RCA: 534] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 05/23/2006] [Accepted: 07/07/2006] [Indexed: 10/24/2022]
Abstract
Balanced control of neuronal activity is central in maintaining function and viability of neuronal circuits. The endocannabinoid system tightly controls neuronal excitability. Here, we show that endocannabinoids directly target hippocampal glutamatergic neurons to provide protection against acute epileptiform seizures in mice. Functional CB1 cannabinoid receptors are present on glutamatergic terminals of the hippocampal formation, colocalizing with vesicular glutamate transporter 1 (VGluT1). Conditional deletion of the CB1 gene either in cortical glutamatergic neurons or in forebrain GABAergic neurons, as well as virally induced deletion of the CB1 gene in the hippocampus, demonstrate that the presence of CB1 receptors in glutamatergic hippocampal neurons is both necessary and sufficient to provide substantial endogenous protection against kainic acid (KA)-induced seizures. The direct endocannabinoid-mediated control of hippocampal glutamatergic neurotransmission may constitute a promising therapeutic target for the treatment of disorders associated with excessive excitatory neuronal activity.
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Affiliation(s)
- Krisztina Monory
- Department of Physiological Chemistry, Johannes Gutenberg University, Duesbergweg 6, 55099 Mainz, Germany
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Federico Massa
- Department of Physiological Chemistry, Johannes Gutenberg University, Duesbergweg 6, 55099 Mainz, Germany
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary, University of London, E1 4NS London, United Kingdom
| | - Matthias Eder
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Heike Blaudzun
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Ruth Westenbroek
- Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Wolfgang Kelsch
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Wolfgang Jacob
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Rudolf Marsch
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Marc Ekker
- Department of Biology, Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Jason Long
- Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, California 94143
| | - John L. Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, California 94143
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen 37075, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen 37075, Germany
| | - Matthew During
- Department of Molecular Medicine and Pathology, University of Auckland School of Medicine, Auckland 92019, New Zealand
| | - Matthias Klugmann
- Department of Molecular Medicine and Pathology, University of Auckland School of Medicine, Auckland 92019, New Zealand
| | - Barbara Wölfel
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Hans-Ulrich Dodt
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | | | - Carsten T. Wotjak
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Ken Mackie
- Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Maurice R. Elphick
- School of Biological and Chemical Sciences, Queen Mary, University of London, E1 4NS London, United Kingdom
| | - Giovanni Marsicano
- Department of Physiological Chemistry, Johannes Gutenberg University, Duesbergweg 6, 55099 Mainz, Germany
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
- *Correspondence: (G.M.); (B.L.)
| | - Beat Lutz
- Department of Physiological Chemistry, Johannes Gutenberg University, Duesbergweg 6, 55099 Mainz, Germany
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
- *Correspondence: (G.M.); (B.L.)
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29
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Abstract
The endocannabinoid signalling system in mammals comprises several molecular components, including cannabinoid receptors (e.g. CB1, CB2), putative endogenous ligands for these receptors [e.g. anandamide, 2-arachidonoylglycerol (2-AG)] and enzymes involved in the biosynthesis and inactivation of anandamide (e.g. NAPE-PLD, FAAH) and 2-AG (e.g. DAG lipase, MGL). In this review we examine the occurrence of these molecules in non-mammalian organisms (in particular, animals and plants) by surveying published data and by basic local alignment search tool (BLAST) analysis of the GenBank database and of genomic sequence data from several vertebrate and invertebrate species. We conclude that the ability of cells to synthesise molecules that are categorised as "endocannabinoids" in mammals is an evolutionarily ancient phenomenon that may date back to the unicellular common ancestor of animals and plants. However, exploitation of these molecules for intercellular signalling may have occurred independently in different lineages during the evolution of the eukaryotes. The CB1- and CB2-type receptors that mediate effects of endocannabinoids in mammals occur throughout the vertebrates, and an orthologue of vertebrate cannabinoid receptors was recently identified in the deuterostomian invertebrate Ciona intestinalis (CiCBR). However, orthologues of the vertebrate cannabinoid receptors are not found in protostomian invertebrates (e.g. Drosophila, Caenorhabditis elegans). Therefore, it is likely that a CB1/CB2-type cannabinoid receptor originated in a deuterostomian invertebrate. This phylogenetic information provides a basis for exploitation of selected non-mammalian organisms as model systems for research on endocannabinoid signalling.
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Affiliation(s)
- M R Elphick
- School of Biological Sciences, Queen Mary, University of London, London E1 4NS, UK.
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30
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Egertová M, Michael GJ, Cravatt BF, Elphick MR. Fatty acid amide hydrolase in brain ventricular epithelium: mutually exclusive patterns of expression in mouse and rat. J Chem Neuroanat 2004; 28:171-81. [PMID: 15482903 DOI: 10.1016/j.jchemneu.2004.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 07/19/2004] [Accepted: 07/19/2004] [Indexed: 11/20/2022]
Abstract
Fatty acid amides and fatty acid ethanolamides are novel signalling molecules exemplified by the sleep-inducing lipid oleamide and the endocannabinoid anandamide, respectively. These substances are inactivated by fatty acid amide hydrolase (FAAH), an enzyme that is expressed by neurons and non-neuronal cells in the brain. In the rat, FAAH-immunoreactivity has been detected in epithelial cells of the choroid plexus and, in accordance with this finding, here we report FAAH mRNA expression in rat choroid plexus epithelium using in situ hybridisation methods. Surprisingly, a comparative analysis of mouse brain did not reveal FAAH mRNA expression or FAAH-immunoreactivity in the choroid plexus of this species. FAAH-immunoreactivity was, however, detected in non-choroidal ventricular ependymal cells in the mouse brain and the specificity of this immunostaining was confirmed by analysis of FAAH-knockout mice. FAAH-immunoreactivity was detected in ependymal cells throughout the ventricles of the mouse brain but with regional variation in the intensity of immunostaining. Intriguingly, in rat brain, although FAAH expression is observed in choroid plexus epithelial cells, little or no FAAH-immunoreactivity is present in the ventricular ependyma. Thus, there are mutually exclusive patterns of FAAH expression in the ventricular epithelium of rat and mouse brain. Our observations provide the basis for an experimental analysis that exploits differences in FAAH expression in rat and mouse to investigate FAAH function in ventricular epithelial cells and, in particular, the role of FAAH in regulating the sleep-inducing agent oleamide in cerebrospinal fluid.
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Affiliation(s)
- Michaela Egertová
- School of Biological Sciences, Queen Mary, University of London, London E1 4NS, UK
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31
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Bridges D, Rice ASC, Egertová M, Elphick MR, Winter J, Michael GJ. Localisation of cannabinoid receptor 1 in rat dorsal root ganglion using in situ hybridisation and immunohistochemistry. Neuroscience 2003; 119:803-12. [PMID: 12809701 DOI: 10.1016/s0306-4522(03)00200-8] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study we used in situ hybridisation and double-labelling immunohistochemistry to characterise cannabinoid receptor 1 (CB(1)) expression in rat lumbar dorsal root ganglion (DRG) neurons.Approximately 25% of DRG neurons expressed CB(1) mRNA and displayed immunoreactivity for CB(1). Sixty-nine percent to 82% of CB(1)-expressing cells were also immunoreactive for neurofilament 200, indicative of myelinated A-fibre neurons, which tend to be large- and medium-sized DRG neurons (>600 microm(2)). Approximately 10% of CB1-expressing cells also expressed transient receptor potential vanilloid family ion channel 2 (TRPV2), the noxious heat-transducing channel found in medium to large lightly myelinated Adelta-fibre DRG neurons. Seventeen percent to 26% of CB(1)-expressing cells co-stained using Isolectin B4, 9-10% for calcitonin gene-related peptide and 11-20% for transient receptor potential vanilloid family ion channel 1 (TRPV1), predominantly markers of small non-myelinated C-fibre DRG neurons (<600 microm(2)). These findings suggest that whilst a wide range of DRG neuron phenotypes express CB(1), it is predominantly associated with myelinated fibres.
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MESH Headings
- Animals
- Calcitonin Gene-Related Peptide/metabolism
- Cell Size/physiology
- Fluorescent Antibody Technique
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Glycoproteins
- Lectins/metabolism
- Male
- Mechanoreceptors/cytology
- Mechanoreceptors/metabolism
- Mice
- Mice, Knockout
- Nerve Fibers, Myelinated/metabolism
- Nerve Fibers, Myelinated/ultrastructure
- Nerve Fibers, Unmyelinated/metabolism
- Nerve Fibers, Unmyelinated/ultrastructure
- Neurofilament Proteins/metabolism
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Nociceptors/cytology
- Nociceptors/metabolism
- Pain/genetics
- Pain/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Cannabinoid
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
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Affiliation(s)
- D Bridges
- Pain Research, Department of Anaesthetics, Faculty of Medicine, Imperial College, Chelsea and Westminster Hospital Campus, London, UK
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32
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Egertová M, Cravatt BF, Elphick MR. Comparative analysis of fatty acid amide hydrolase and cb(1) cannabinoid receptor expression in the mouse brain: evidence of a widespread role for fatty acid amide hydrolase in regulation of endocannabinoid signaling. Neuroscience 2003; 119:481-96. [PMID: 12770562 DOI: 10.1016/s0306-4522(03)00145-3] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Fatty acid amide hydrolase (FAAH) catalyses hydrolysis of the endocannabinoid arachidonoylethanolamide ("anandamide") in vitro and regulates anandamide levels in the brain. In the cerebellar cortex, hippocampus and neocortex of the rat brain, FAAH is located in the somata and dendrites of neurons that are postsynaptic to axon fibers expressing the CB(1) cannabinoid receptor [Proc R Soc Lond B 265 (1998) 2081]. This complementary pattern of FAAH and CB(1) expression provided the basis for a hypothesis that endocannabinoids may function as retrograde signaling molecules at synapses in the brain [Proc R Soc Lond B 265 (1998) 2081; Phil Trans R Soc Lond 356 (2001) 381] and subsequent experimental studies have confirmed this [Science 296 (2002) 678]. To assess more widely the functions of FAAH in the brain and the potential impact of FAAH activity on the spatiotemporal dynamics of endocannabinoid signaling in different regions of the brain, here we have employed immunocytochemistry to compare the distribution of FAAH and CB(1) throughout the mouse brain, using FAAH(-/-) mice as negative controls to validate the specificity of FAAH-immunoreactivity observed in wild type animals. In many regions of the brain, a complementary pattern of FAAH and CB(1) expression was observed, with FAAH-immunoreactive neuronal somata and dendrites surrounded by CB(1)-immunoreactive fibers. In these regions of the brain, FAAH may regulate postsynaptic formation of anandamide, thereby influencing the spatiotemporal dynamics of retrograde endocannabinoid signaling. However, in some regions of the brain such as the globus pallidus and substantia nigra pars reticulata, CB(1) receptors are abundant but with little or no associated FAAH expression and in these brain regions the spatial impact and/or duration of endocannabinoid signaling may be less restricted than in regions enriched with FAAH. A more complex situation arises in several regions of the brain where both FAAH and CB(1) are expressed but in a non-complementary pattern, with FAAH located in neurons and/or oligodendrocytes that are proximal but not postsynaptic to CB(1)-expressing axon fibers. Here FAAH may nevertheless influence endocannabinoid signaling but more remotely. Finally, there are regions of the brain where FAAH-immunoreactive neurons and/or oligodendrocytes occur in the absence of CB(1)-immunoreactive fibers and here FAAH may be involved in regulation of signaling mediated by other endocannabinoid receptors or by receptors for other fatty acid amide signaling molecules. In conclusion, by comparing the distribution of FAAH and CB(1) in the mouse brain, we have provided a neuroanatomical framework for comparative analysis of the role of FAAH in regulation of the spatiotemporal dynamics of retrograde endocannabinoid signaling in different regions of the brain.
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Affiliation(s)
- M Egertová
- School of Biological Sciences, Queen Mary, University of London, London E1 4NS, UK
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33
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Abstract
The plant Cannabis sativa has been used by humans for thousands of years because of its psychoactivity. The major psychoactive ingredient of cannabis is Delta(9)-tetrahydrocannabinol, which exerts effects in the brain by binding to a G-protein-coupled receptor known as the CB1 cannabinoid receptor. The discovery of this receptor indicated that endogenous cannabinoids may occur in the brain, which act as physiological ligands for CB1. Two putative endocannabinoid ligands, arachidonylethanolamide ('anandamide') and 2-arachidonylglycerol, have been identified, giving rise to the concept of a cannabinoid signalling system. Little is known about how or where these compounds are synthesized in the brain and how this relates to CB1 expression. However, detailed neuroanatomical and electrophysiological analysis of mammalian nervous systems has revealed that the CB1 receptor is targeted to the presynaptic terminals of neurons where it acts to inhibit release of 'classical' neurotransmitters. Moreover, an enzyme that inactivates endocannabinoids, fatty acid amide hydrolase, appears to be preferentially targeted to the somatodendritic compartment of neurons that are postsynaptic to CB1-expressing axon terminals. Based on these findings, we present here a model of cannabinoid signalling in which anandamide is synthesized by postsynaptic cells and acts as a retrograde messenger molecule to modulate neurotransmitter release from presynaptic terminals. Using this model as a framework, we discuss the role of cannabinoid signalling in different regions of the nervous system in relation to the characteristic physiological actions of cannabinoids in mammals, which include effects on movement, memory, pain and smooth muscle contractility. The discovery of the cannabinoid signalling system in mammals has prompted investigation of the occurrence of this pathway in non-mammalian animals. Here we review the evidence for the existence of cannabinoid receptors in non-mammalian vertebrates and invertebrates and discuss the evolution of the cannabinoid signalling system. Genes encoding orthologues of the mammalian CB1 receptor have been identified in a fish, an amphibian and a bird, indicating that CB1 receptors may occur throughout the vertebrates. Pharmacological actions of cannabinoids and specific binding sites for cannabinoids have been reported in several invertebrate species, but the molecular basis for these effects is not known. Importantly, however, the genomes of the protostomian invertebrates Drosophila melanogaster and Caenorhabditis elegans do not contain CB1 orthologues, indicating that CB1-like cannabinoid receptors may have evolved after the divergence of deuterostomes (e.g. vertebrates and echinoderms) and protostomes. Phylogenetic analysis of the relationship of vertebrate CB1 receptors with other G-protein-coupled receptors reveals that the paralogues that appear to share the most recent common evolutionary origin with CB1 are lysophospholipid receptors, melanocortin receptors and adenosine receptors. Interestingly, as with CB1, each of these receptor types does not appear to have Drosophila orthologues, indicating that this group of receptors may not occur in protostomian invertebrates. We conclude that the cannabinoid signalling system may be quite restricted in its phylogenetic distribution, probably occurring only in the deuterostomian clade of the animal kingdom and possibly only in vertebrates.
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Affiliation(s)
- M R Elphick
- School of Biological Sciences, Queen Mary, University of London, London E1 4NS, UK. m.r.elphick@@qmw.ac.uk
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34
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Abstract
The CB(1)-type cannabinoid receptor mediates physiologic effects of Delta(9)-tetrahydrocannabinol, the psychoactive ingredient of the drug marijuana. In this report, the authors analyse the expression of CB(1) in the rat brain by using antibodies to the C-terminal 13 amino acids of the receptor. Western blot analysis of rat brain membranes revealed a prominent immunoreactive band with a molecular mass ( approximately 53 kDa) consistent with that predicted for CB(1) from the rat cDNA sequence. In addition, however, less intense immunoreactive bands corresponding to glycosylated ( approximately 62 kDa) and putative N-terminally shorter ( approximately 45 kDa) isoforms of CB(1) were detected. The distribution of CB(1)-immunoreactivity in rat brain was similar to the distribution of binding sites for radiolabelled cannabinoids, with high levels of expression in the olfactory system, the hippocampal formation, the basal ganglia, the cerebellum, and the neocortex. This provides important evidence that CB(1) is likely to be largely responsible for mediating effects of cannabinoids in the brain. CB(1) immunoreactivity was associated with nerve fibre systems and axon terminals but was not detected in neuronal somata. This is consistent with the presynaptic inhibitory effects of cannabinoids on neurotransmitter release in the brain. Detailed immunocytochemical analysis of anatomically or functionally related regions of the brain revealed the location of CB(1) receptors within identified neural circuits. Determination of the cellular and subcellular location of CB(1) within known neuronal circuits of the brain provides an anatomic framework for interpretation of the neurophysiologic and behavioural effects of cannabinoids.
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Affiliation(s)
- M Egertová
- School of Biological Sciences, Queen Mary and Westfield College, University of London, London E1 4NS, United Kingdom
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35
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Abstract
While evidence implicates the endogenous cannabinoid system as a novel analgesic target at a spinal level, detailed analysis of the distribution of the cannabinoid receptor CB(1) in spinal cord has not been reported. Here, immunocytochemical studies were used to characterize the CB(1) receptor expression in rat spinal cord. Staining was found in the dorsolateral funiculus, the superficial dorsal horn (a double band of CB(1) immunoreactivity (ir) in laminae I and II inner/III transition), and lamina X. Although CB(1)-ir was present in the same laminae as primary afferent nociceptor markers, there was limited colocalization at an axonal level. Interruption of both primary afferent input by dorsal root rhizotomy and descending input by rostral spinal cord hemisection produced minor changes in CB(1)-ir. This and colocalization of CB(1)-ir with interneurons expressing protein kinase C subunit gamma-ir suggest that the majority of CB(1) expression is on spinal interneurons. These data provide a framework and implicate novel analgesic mechanisms for spinal actions of cannabinoids at the CB(1) receptor.
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Affiliation(s)
- W P Farquhar-Smith
- Pain Research Group, Imperial College School of Medicine, St. Mary's Hospital Campus, London, W2 1NY, United Kingdom
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36
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Egertová M, Cravatt BF, Elphick MR. Fatty acid amide hydrolase expression in rat choroid plexus: possible role in regulation of the sleep-inducing action of oleamide. Neurosci Lett 2000; 282:13-6. [PMID: 10713385 DOI: 10.1016/s0304-3940(00)00841-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The enzyme fatty acid amide hydrolase (FAAH) catalyses hydrolysis of oleamide, a sleep-inducing lipid whose concentration in the cerebrospinal fluid (CSF) is elevated in sleep-deprived mammals. Previous studies have reported expression of FAAH by distinct populations of neurons in the rat brain. Here we demonstrate using immunocytochemical methods that FAAH is also expressed by non-neuronal epithelial cells of the rat choroid plexus. The choroid plexus is formed by invaginations of the pia mater into the ventricle cavities of the brain and an important function of the choroidal epithelium is to regulate production and composition of CSF. Therefore, the role of FAAH in epithelial cells of the choroid plexus may be to control the concentration of oleamide in the CSF and as such FAAH may exert an important regulatory role in shaping the duration and magnitude of the sleep-inducing effect of endogenously or exogenously derived oleamide.
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Affiliation(s)
- M Egertová
- School of Biological Sciences, Queen Mary and Westfield College, University of London, Mile End Road, London, UK
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37
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Egertová M, Giang DK, Cravatt BF, Elphick MR. A new perspective on cannabinoid signalling: complementary localization of fatty acid amide hydrolase and the CB1 receptor in rat brain. Proc Biol Sci 1998; 265:2081-5. [PMID: 9842734 PMCID: PMC1689501 DOI: 10.1098/rspb.1998.0543] [Citation(s) in RCA: 229] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CB1-type cannabinoid receptors in the brain mediate effects of the drug cannabis. Anandamide and sn-2 arachidonylglycerol (2-AG) are putative endogenous ligands for CB1 receptors, but it is not known which cells in the brain produce these molecules. Recently, an enzyme which catalyses hydrolysis of anandamide and 2-AG, known as fatty acid amide hydrolase (FAAH), was identified in mammals. Here we have analysed the distribution of FAAH in rat brain and compared its cellular localization with CB1-type cannabinoid receptors using immunocytochemistry. High concentrations of FAAH activity were detected in the cerebellum, hippocampus and neocortex, regions of the rat brain which are enriched with cannabinoid receptors. Immunocytochemical analysis of these brain regions revealed a complementary pattern of FAAH and CB1 expression with CB1 immunoreactivity occurring in fibres surrounding FAAH-immunoreactive cell bodies and/or dendrites. In the cerebellum, FAAH was expressed in the cell bodies of Purkinje cells and CB1 was expressed in the axons of granule cells and basket cells, neurons which are presynaptic to Purkinje cells. The close correspondence in the distribution of FAAH and CB1 in rat brain and the complementary pattern of FAAH and CB1 expression at the cellular level provides important new evidence that FAAH may participate in cannabinoid signalling mechanisms of the brain.
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Affiliation(s)
- M Egertová
- School of Biological Sciences, Queen Mary and Westfield College, University of London, UK
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38
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Glyn MC, Egertová M, Gazdova B, Kovarik A, Bezdek M, Leitch AR. The influence of 5-azacytidine on the condensation of the short arm of rye chromosome 1R in Triticum aestivum L. root tip meristematic nuclei. Chromosoma 1997; 106:485-92. [PMID: 9426280 DOI: 10.1007/pl00007688] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This paper describes the effects of 5-azacytidine on the condensation state of rye (Secale cereale L.) chromatin introduced into the wheat genome (Triticum aestivum L. cv. Beaver). The wheat cultivar Beaver carries a translocation between the short arm of rye chromosome 1R (1RS) and the long arm of wheat chromosome 1B (1BL/1RS). 1RS can be detected using genomic in situ hybridisation and carries a ribosomal DNA (rDNA) locus that can be simultaneously detected using multiple labelling strategies. The rDNA locus divides 1RS into a distal region that is gene rich and a proximal region that is gene poor and highly methylated. 1RS also carries a large block of subtelomeric heterochromatin. The drug, which acts to inhibit DNA methylation in plants, has three pronounced effects on interphase nuclei. (1) It induces aberrant condensation of the rye subtelomeric heterochromatin and in many cases induces sister chromatid separation in the subtelomeric heterochromatin of G2 nuclei. (2) Nuclei trisomic for 1RS are observed at low frequency in treated material and are probably a consequence of aberrant sister chromatid separation or condensation. (3) The drug alters normal condensation of 1RS euchromatin. However, contrary to expectation the effect is not simply to induce decondensation. The proximal region of the arm actually condenses at low levels of drug administration while the distal region remains unaltered or increases its decondensation state. Increasing the concentration of 5-azacytidine induces a biphasic response and at the highest concentration used all regions of the arm show signs of decondensation. Thus the influence of the drug on chromatin condensation depends on the genomic structure.
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Affiliation(s)
- M C Glyn
- School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK
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39
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Glyn MCP, Egertová M, Gazdova B, Kovarik A, Bezdek M, Leitch AR. The influence of 5-azacytidine on the condensation of the short arm of rye chromosome 1R in. Chromosoma 1997. [DOI: 10.1007/s004120050270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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