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Bárez-López S, Bishop P, Searby D, Murphy D, Greenwood MP. Male rat hypothalamic extraretinal photoreceptor Opsin3 is sensitive to osmotic stimuli and light. J Neuroendocrinol 2024; 36:e13363. [PMID: 38192267 DOI: 10.1111/jne.13363] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/13/2023] [Accepted: 12/16/2023] [Indexed: 01/10/2024]
Abstract
The light-sensitive protein Opsin 3 (Opn3) is present throughout the mammalian brain; however, the role of Opn3 in this organ remains unknown. Since Opn3 encoded mRNA is modulated in the supraoptic and paraventricular nucleus of the hypothalamus in response to osmotic stimuli, we have explored by in situ hybridization the expression of Opn3 in these nuclei. We have demonstrated that Opn3 is present in the male rat magnocellular neurones expressing either the arginine vasopressin or oxytocin neuropeptides and that Opn3 increases in both neuronal types in response to osmotic stimuli, suggesting that Opn3 functions in both cell types and that it might be involved in regulating water balance. Using rat hypothalamic organotypic cultures, we have demonstrated that the hypothalamus is sensitive to light and that the observed light sensitivity is mediated, at least in part, by Opn3. The data suggests that hypothalamic Opn3 can mediate a light-sensitive role to regulate circadian homeostatic processes.
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Affiliation(s)
- Soledad Bárez-López
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Paul Bishop
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Daniel Searby
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - David Murphy
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
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Gillard BT, Amor N, Iraizoz FA, Pauža AG, Campbell C, Greenwood MP, Alagaili AN, Murphy D. Mobilisation of jerboa kidney gene networks during dehydration and opportunistic rehydration. iScience 2023; 26:107574. [PMID: 37664605 PMCID: PMC10470305 DOI: 10.1016/j.isci.2023.107574] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/30/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023] Open
Abstract
Desert animals have evolved systems that enable them to thrive under dry conditions. Focusing on the kidney, we have investigated the transcriptomic adaptations that enable a desert rodent, the Lesser Egyptian Jerboa (Jaculus jaculus), to withstand water deprivation and opportunistic rehydration. Analysis of the whole kidney transcriptome showed many differentially expressed genes in the Jerboa kidney, 6.4% of genes following dehydration and an even greater number (36.2%) following rehydration compared to control. Genes correlated with the rehydration condition included many ribosomal protein coding genes suggesting a concerted effort to accelerate protein synthesis when water is made available. We identify an increase in TGF-beta signaling antagonists in dehydration (e.g., GREM2). We also describe expression of multiple aquaporin and solute carrier transporters mapped to specific nephron segments. The desert adapted renal transcriptome presented here is a valuable resource to expand our understanding of osmoregulation beyond that derived from model organisms.
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Affiliation(s)
- Benjamin T. Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Nabil Amor
- LR18ES05, Laboratory of Biodiversity, Parasitology and Ecology of Aquatic Ecosystems, Department of Biology - Faculty of Sciences of Tunis, University of Tunis El Manar, Tunisia
| | - Fernando Alvira Iraizoz
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Audrys G. Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Colin Campbell
- Department of Engineering Mathematics, Ada Lovelace Building, University of Bristol, Bristol, England
| | - Michael P. Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | | | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
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Harris RA, Bush AH, Eagar TN, Qian J, Greenwood MP, Opekun AR, Baldassano R, Guthery SL, Noe JD, Otley A, Rosh JR, Kugathasan S, Kellermayer R. Exome Sequencing Implicates DGKZ , ESRRA , and GXYLT1 for Modulating Granuloma Formation in Crohn Disease. J Pediatr Gastroenterol Nutr 2023; 77:354-357. [PMID: 37347142 PMCID: PMC10528115 DOI: 10.1097/mpg.0000000000003873] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Non-caseating granulomas may indicate a more aggressive phenotype of Crohn disease (CD). Genetic associations of granulomatous CD (GCD) may help elucidate disease pathogenesis. Whole-exome sequencing was performed on peripheral blood-derived DNA from 17 pediatric patients with GCD and 19 with non-GCD (NGCD), and from an independent validation cohort of 44 GCD and 19 NGCD cases. PLINK (a tool set for whole-genome association and population-based linkage analyses) analysis was used to identify single nucleotide polymorphisms (SNPs) differentiating between groups, and subgroup allele frequencies were also compared to a public genomic database (gnomAD). The Combined Annotation Dependent Depletion scoring tool was used to predict deleteriousness of SNPs. Human leukocyte antigen (HLA) haplotype findings were compared to a control group (n = 8496). PLINK-based analysis between GCD and NGCD groups did not find consistently significant hits. gnomAD control comparisons, however, showed consistent subgroup associations with DGKZ , ESRRA , and GXYLT1 , genes that have been implicated in mammalian granulomatous inflammation. Our findings may guide future research and precision medicine.
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Affiliation(s)
- R. Alan Harris
- Department of Molecular and Human Genetics, Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
- contributed equally
| | - Allyson H Bush
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, Baylor College of Medicine/Texas Children’s Hospital, Houston, TX
- contributed equally
| | - Todd N Eagar
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY
| | - Justin Qian
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, Baylor College of Medicine/Texas Children’s Hospital, Houston, TX
| | - Michael P Greenwood
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY
| | - Antone R Opekun
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, Baylor College of Medicine/Texas Children’s Hospital, Houston, TX
| | - Robert Baldassano
- Division of Gastroenterology, Hepatology and Nutrition, University of Pennsylvania, Children’s Hospital of Philadelphia, PA
| | - Stephen L Guthery
- Department of Pediatrics, University of Utah and Intermountain Primary Children’s Hospital, Salt Lake City, UT
| | - Joshua D Noe
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Medical College of Wisconsin, Milwaukee, WI
| | - Anthony Otley
- IWK Health/Dalhousie University, Halifax, Nova Scotia, Canada
| | - Joel R. Rosh
- Goryeb Children’s Hospital/Atlantic Children’s Health, Morristown, NJ
| | - Subra Kugathasan
- Departments of Pediatrics and Human Genetics at Emory University School of Medicine, Atlanta, GA
| | - Richard Kellermayer
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, Baylor College of Medicine/Texas Children’s Hospital, Houston, TX
- Children’s Nutrition and Research Center, Houston, TX
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Bárez-López S, Gadd GJ, Pauža AG, Murphy D, Greenwood MP. Isoflurane Rapidly Modifies Synaptic and Cytoskeletal Phosphoproteomes of the Supraoptic Nucleus of the Hypothalamus and the Cortex. Neuroendocrinology 2023; 113:1008-1023. [PMID: 37271138 DOI: 10.1159/000531352] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 02/17/2023] [Accepted: 05/24/2023] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Despite the widespread use of general anaesthetics, the mechanisms mediating their effects are still not understood. Although suppressed in most parts of the brain, neuronal activity, as measured by FOS activation, is increased in the hypothalamic supraoptic nucleus (SON) by numerous general anaesthetics, and evidence points to this brain region being involved in the induction of general anaesthesia (GA) and natural sleep. Posttranslational modifications of proteins, including changes in phosphorylation, enable fast modulation of protein function which could be underlying the rapid effects of GA. In order to identify potential phosphorylation events in the brain-mediating GA effects, we have explored the phosphoproteome responses in the rat SON and compared these to cingulate cortex (CC) which displays no FOS activation in response to general anaesthetics. METHODS Adult Sprague-Dawley rats were treated with isoflurane for 15 min. Proteins from the CC and SON were extracted and processed for nano-LC mass spectrometry (LC-MS/MS). Phosphoproteomic determinations were performed by LC-MS/MS. RESULTS We found many changes in the phosphoproteomes of both the CC and SON in response to 15 min of isoflurane exposure. Pathway analysis indicated that proteins undergoing phosphorylation adaptations are involved in cytoskeleton remodelling and synaptic signalling events. Importantly, changes in protein phosphorylation appeared to be brain region specific suggesting that differential phosphorylation adaptations might underlie the different neuronal activity responses to GA between the CC and SON. CONCLUSION In summary, these data suggest that rapid posttranslational modifications in proteins involved in cytoskeleton remodelling and synaptic signalling events might mediate the central mechanisms mediating GA.
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Affiliation(s)
- Soledad Bárez-López
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - George J Gadd
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
- Translational Cardio-Respiratory Research Group, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
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Elsamad G, Mecawi AS, Pauža AG, Gillard B, Paterson A, Duque VJ, Šarenac O, Žigon NJ, Greenwood M, Greenwood MP, Murphy D. Ageing restructures the transcriptome of the hypothalamic supraoptic nucleus and alters the response to dehydration. NPJ Aging 2023; 9:12. [PMID: 37264028 PMCID: PMC10234251 DOI: 10.1038/s41514-023-00108-2] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/04/2023] [Indexed: 06/03/2023]
Abstract
Ageing is associated with altered neuroendocrine function. In the context of the hypothalamic supraoptic nucleus, which makes the antidiuretic hormone vasopressin, ageing alters acute responses to hyperosmotic cues, rendering the elderly more susceptible to dehydration. Chronically, vasopressin has been associated with numerous diseases of old age, including type 2 diabetes and metabolic syndrome. Bulk RNAseq transcriptome analysis has been used to catalogue the polyadenylated supraoptic nucleus transcriptomes of adult (3 months) and aged (18 months) rats in basal euhydrated and stimulated dehydrated conditions. Gene ontology and Weighted Correlation Network Analysis revealed that ageing is associated with alterations in the expression of extracellular matrix genes. Interestingly, whilst the transcriptomic response to dehydration is overall blunted in aged animals compared to adults, there is a specific enrichment of differentially expressed genes related to neurodegenerative processes in the aged cohort, suggesting that dehydration itself may provoke degenerative consequences in aged rats.
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Affiliation(s)
- Ghadir Elsamad
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - André Souza Mecawi
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
- Translational Cardio-Respiratory Research Group, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Benjamin Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
- Insilico Consulting Ltd., Wapping Wharf, Bristol, England
| | - Victor J Duque
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Olivera Šarenac
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Department of Safety Pharmacology, Abbvie, North Chicago, Illinois, USA
| | - Nina Japundžić Žigon
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Mingkwan Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England.
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Bárez-López S, Mecawi AS, Bryan N, Pauža AG, Duque VJ, Gillard BT, Murphy D, Greenwood MP. Translational and post-translational dynamics in a model peptidergic system. Mol Cell Proteomics 2023; 22:100544. [PMID: 37030596 DOI: 10.1016/j.mcpro.2023.100544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 03/30/2023] [Accepted: 04/04/2023] [Indexed: 04/10/2023] Open
Abstract
The cell bodies of hypothalamic magnocellular neurones are densely packed in the hypothalamic supraoptic nucleus whereas their axons project to the anatomically discrete posterior pituitary gland. We have taken advantage of this unique anatomical structure to establish proteome and phosphoproteome dynamics in neuronal cell bodies and axonal terminals in response to physiological stimulation. We have found that proteome and phosphoproteome responses to neuronal stimulation are very different between somatic and axonal neuronal compartments, indicating the need of each cell domain to differentially adapt. In particular, changes in the phosphoproteome in the cell body are involved in the reorganisation of the cytoskeleton and in axonal terminals the regulation of synaptic and secretory processes. We have identified that prohormone precursors including vasopressin and oxytocin are phosphorylated in axonal terminals and are hyperphosphorylated following stimulation. By multi-omic integration of transcriptome and proteomic data we identify changes to proteins present in afferent inputs to this nucleus.
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Affiliation(s)
- Soledad Bárez-López
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - André S Mecawi
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Natasha Bryan
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Victor J Duque
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Benjamin T Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
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Greenwood MP, Greenwood M, Bárez-López S, Hawkins JW, Short K, Tatovic D, Murphy D. Osmoadaptive GLP-1R signalling in hypothalamic neurones inhibits antidiuretic hormone synthesis and release. Mol Metab 2023; 70:101692. [PMID: 36773648 PMCID: PMC9969259 DOI: 10.1016/j.molmet.2023.101692] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
OBJECTIVES The excessive release of the antidiuretic hormone vasopressin is implicated in many diseases including cardiovascular disease, diabetes, obesity, and metabolic syndrome. Once thought to be elevated as a consequence of diseases, data now supports a more causative role. We have previously identified CREB3L1 as a transcription factor that co-ordinates vasopressin synthesis and release in the hypothalamus. The objective here was to identify mechanisms orchestrated by CREB3L1 that co-ordinate vasopressin release. METHODS We mined Creb3l1 knockdown SON RNA-seq data to identify downstream target genes. We proceeded to investigate the expression of these genes and associated pathways in the supraoptic nucleus of the hypothalamus in response to physiological and pharmacological stimulation. We used viruses to selectively knockdown gene expression in the supraoptic nucleus and assessed physiological and metabolic parameters. We adopted a phosphoproteomics strategy to investigate mechanisms that facilitate hormone release by the pituitary gland. RESULTS We discovered glucagon like peptide 1 receptor (Glp1r) as a downstream target gene and found increased expression in stimulated vasopressin neurones. Selective knockdown of supraoptic nucleus Glp1rs resulted in decreased food intake and body weight. Treatment with GLP-1R agonist liraglutide decreased vasopressin synthesis and release. Quantitative phosphoproteomics of the pituitary neurointermediate lobe revealed that liraglutide initiates hyperphosphorylation of presynapse active zone proteins that control vasopressin exocytosis. CONCLUSION In summary, we show that GLP-1R signalling inhibits the vasopressin system. Our data advises that hydration status may influence the pharmacodynamics of GLP-1R agonists so should be considered in current therapeutic strategies.
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Affiliation(s)
- Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Mingkwan Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Soledad Bárez-López
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Joe W Hawkins
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Katherine Short
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
| | - Danijela Tatovic
- Diabetes and Endocrinology Department, North Bristol NHS Trust, Bristol, United Kingdom
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom
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Leyden GM, Greenwood MP, Gaborieau V, Han Y, Amos CI, Brennan P, Murphy D, Davey Smith G, Richardson TG. Disentangling the aetiological pathways between body mass index and site-specific cancer risk using tissue-partitioned Mendelian randomisation. Br J Cancer 2023; 128:618-625. [PMID: 36434155 PMCID: PMC9938133 DOI: 10.1038/s41416-022-02060-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 04/28/2022] [Revised: 10/30/2022] [Accepted: 11/02/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Body mass index (BMI) is known to influence the risk of various site-specific cancers, however, dissecting which subcomponents of this heterogenous risk factor are predominantly responsible for driving disease effects has proven difficult to establish. We have leveraged tissue-specific gene expression to separate the effects of distinct phenotypes underlying BMI on the risk of seven site-specific cancers. METHODS SNP-exposure estimates were weighted in a multivariable Mendelian randomisation analysis by their evidence for colocalization with subcutaneous adipose- and brain-tissue-derived gene expression using a recently developed methodology. RESULTS Our results provide evidence that brain-tissue-derived BMI variants are predominantly responsible for driving the genetically predicted effect of BMI on lung cancer (OR: 1.17; 95% CI: 1.01-1.36; P = 0.03). Similar findings were identified when analysing cigarettes per day as an outcome (Beta = 0.44; 95% CI: 0.26-0.61; P = 1.62 × 10-6), highlighting a possible shared aetiology or mediator effect between brain-tissue BMI, smoking and lung cancer. Our results additionally suggest that adipose-tissue-derived BMI variants may predominantly drive the effect of BMI and increased risk for endometrial cancer (OR: 1.71; 95% CI: 1.07-2.74; P = 0.02), highlighting a putatively important role in the aetiology of endometrial cancer. CONCLUSIONS The study provides valuable insight into the divergent underlying pathways between BMI and the risk of site-specific cancers.
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Affiliation(s)
- Genevieve M Leyden
- MRC Integrative Epidemiology Unit, Bristol Population Health Science Institute, University of Bristol, Bristol, BS8 2BN, UK.
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK.
| | - Michael P Greenwood
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - Valérie Gaborieau
- Genomic Epidemiology Branch, International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Younghun Han
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, USA
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Christopher I Amos
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, USA
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
- Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Paul Brennan
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - David Murphy
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - George Davey Smith
- MRC Integrative Epidemiology Unit, Bristol Population Health Science Institute, University of Bristol, Bristol, BS8 2BN, UK
| | - Tom G Richardson
- MRC Integrative Epidemiology Unit, Bristol Population Health Science Institute, University of Bristol, Bristol, BS8 2BN, UK.
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Greenwood M, Gillard BT, Farrukh R, Paterson A, Althammer F, Grinevich V, Murphy D, Greenwood MP. Transcription factor Creb3l1 maintains proteostasis in neuroendocrine cells. Mol Metab 2022; 63:101542. [PMID: 35803572 PMCID: PMC9294333 DOI: 10.1016/j.molmet.2022.101542] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/29/2022] [Accepted: 07/03/2022] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES Dynamic changes to neuropeptide hormone synthesis and secretion by hypothalamic neuroendocrine cells is essential to ensure metabolic homeostasis. The specialised molecular mechanisms that allow neuroendocrine cells to synthesise and secrete vast quantities of neuropeptides remain ill defined. The objective of this study was to identify novel genes and pathways controlled by transcription factor and endoplasmic reticulum stress sensor Creb3l1 which is robustly activated in hypothalamic magnocellular neurones in response to increased demand for protein synthesis. METHODS We adopted a multiomic strategy to investigate specific roles of Creb3l1 in rat magnocellular neurones. We first performed chromatin immunoprecipitation followed by genome sequencing (ChIP-seq) to identify Creb3l1 genomic targets and then integrated this data with RNA sequencing data from physiologically stimulated and Creb3l1 knockdown magnocellular neurones. RESULTS The data converged on Creb3l1 targets that code for ribosomal proteins and endoplasmic reticulum proteins crucial for the maintenance of cellular proteostasis. We validated genes that compose the PERK arm of the unfolded protein response pathway including Eif2ak3, Eif2s1, Atf4 and Ddit3 as direct Creb3l1 targets. Importantly, knockdown of Creb3l1 in the hypothalamus led to a dramatic depletion in neuropeptide synthesis and secretion. The physiological outcomes from studies of paraventricular and supraoptic nuclei Creb3l1 knockdown animals were changes to food and water consumption. CONCLUSION Collectively, our data identify Creb3l1 as a comprehensive controller of the PERK signalling pathway in magnocellular neurones in response to physiological stimulation. The broad regulation of neuropeptide synthesis and secretion by Creb3l1 presents a new therapeutic strategy for metabolic diseases.
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Affiliation(s)
- Mingkwan Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Benjamin T Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Rizwan Farrukh
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Ferdinand Althammer
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany.
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA, USA.
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
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Leyden GM, Shapland CY, Davey Smith G, Sanderson E, Greenwood MP, Murphy D, Richardson TG. Harnessing tissue-specific genetic variation to dissect putative causal pathways between body mass index and cardiometabolic phenotypes. Am J Hum Genet 2022; 109:240-252. [PMID: 35090585 DOI: 10.1016/j.ajhg.2021.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/14/2021] [Indexed: 12/11/2022] Open
Abstract
Body mass index (BMI) is a complex disease risk factor known to be influenced by genes acting via both metabolic pathways and appetite regulation. In this study, we aimed to gain insight into the phenotypic consequences of BMI-associated genetic variants, which may be mediated by their expression in different tissues. First, we harnessed meta-analyzed gene expression datasets derived from subcutaneous adipose (n = 1257) and brain (n = 1194) tissue to identify 86 and 140 loci, respectively, which provided evidence of genetic colocalization with BMI. These two sets of tissue-partitioned loci had differential effects with respect to waist-to-hip ratio, suggesting that the way they influence fat distribution might vary despite their having very similar average magnitudes of effect on BMI itself (adipose = 0.0148 and brain = 0.0149 standard deviation change in BMI per effect allele). For instance, BMI-associated variants colocalized with TBX15 expression in adipose tissue (posterior probability [PPA] = 0.97), but not when we used TBX15 expression data derived from brain tissue (PPA = 0.04) This gene putatively influences BMI via its role in skeletal development. Conversely, there were loci where BMI-associated variants provided evidence of colocalization with gene expression in brain tissue (e.g., NEGR1, PPA = 0.93), but not when we used data derived from adipose tissue, suggesting that these genes might be more likely to influence BMI via energy balance. Leveraging these tissue-partitioned variant sets through a multivariable Mendelian randomization framework provided strong evidence that the brain-tissue-derived variants are predominantly responsible for driving the genetically predicted effects of BMI on cardiovascular-disease endpoints (e.g., coronary artery disease: odds ratio = 1.05, 95% confidence interval = 1.04-1.07, p = 4.67 × 10-14). In contrast, our analyses suggested that the adipose tissue variants might predominantly be responsible for the underlying relationship between BMI and measures of cardiac function, such as left ventricular stroke volume (beta = 0.21, 95% confidence interval = 0.09-0.32, p = 6.43 × 10-4).
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11
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Pauza AG, Thakkar P, Tasic T, Felippe I, Bishop P, Greenwood MP, Rysevaite-Kyguoliene K, Ast J, Broichhagen J, Hodson DJ, Salgado HC, Pauza DH, Japundzic-Zigon N, Paton JFR, Murphy D. GLP1R Attenuates Sympathetic Response to High Glucose via Carotid Body Inhibition. Circ Res 2022; 130:694-707. [PMID: 35100822 PMCID: PMC8893134 DOI: 10.1161/circresaha.121.319874] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [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] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Aberrant sympathetic nerve activity exacerbates cardiovascular risk in hypertension and diabetes, which are common comorbidities, yet clinically sympathetic nerve activity remains poorly controlled. The hypertensive diabetic state is associated with increased reflex sensitivity and tonic drive from the peripheral chemoreceptors, the cause of which is unknown. We have previously shown hypertension to be critically dependent on the carotid body (CB) input in spontaneously hypertensive rat, a model that also exhibits a number of diabetic traits. CB overstimulation by insulin and leptin has been similarly implicated in the development of increased sympathetic nerve activity in metabolic syndrome and obesity. Thus, we hypothesized that in hypertensive diabetic state (spontaneously hypertensive rat), the CB is sensitized by altered metabolic signaling causing excessive sympathetic activity levels and dysfunctional reflex regulation.
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Affiliation(s)
- Audrys G Pauza
- Bristol Medical School, Translational Health Sciences, University of Bristol, United Kingdom (A.G.P., P.B., M.P.G., D.M.)
| | - Pratik Thakkar
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand (P.T., I.F., J.F.R.P.)
| | - Tatjana Tasic
- School of Dental Medicine, University of Belgrade, Serbia (T.T.)
| | - Igor Felippe
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand (P.T., I.F., J.F.R.P.)
| | - Paul Bishop
- Bristol Medical School, Translational Health Sciences, University of Bristol, United Kingdom (A.G.P., P.B., M.P.G., D.M.)
| | - Michael P Greenwood
- Bristol Medical School, Translational Health Sciences, University of Bristol, United Kingdom (A.G.P., P.B., M.P.G., D.M.)
| | | | - Julia Ast
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, United Kingdom (J.A., D.J.H.)
| | | | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, United Kingdom (D.A., D.J.H.).,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, United Kingdom (J.A., D.J.H.)
| | - Helio C Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Brazil (H.C.S.)
| | - Dainius H Pauza
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas (K.R.-K., D.H.P.)
| | - Nina Japundzic-Zigon
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Serbia (N.J.-Z.)
| | - Julian F R Paton
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand (P.T., I.F., J.F.R.P.)
| | - David Murphy
- Bristol Medical School, Translational Health Sciences, University of Bristol, United Kingdom (A.G.P., P.B., M.P.G., D.M.)
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Bárez-López S, Konopacka A, Cross SJ, Greenwood M, Skarveli M, Murphy D, Greenwood MP. Transcriptional and Post-Transcriptional Regulation of Oxytocin and Vasopressin Gene Expression by CREB3L1 and CAPRIN2. Neuroendocrinology 2022; 112:1058-1077. [PMID: 35051932 DOI: 10.1159/000522088] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/06/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Water homoeostasis is achieved by secretion of the peptide hormones arginine vasopressin (AVP) and oxytocin (OXT) that are synthesized by separate populations of magnocellular neurones (MCNs) in the supraoptic and paraventricular (PVN) nuclei of the hypothalamus. To further understand the molecular mechanisms that facilitate biosynthesis of AVP and OXT by MCNs, we have explored the spatiotemporal dynamic, both mRNA and protein expression, of two genes identified by our group as being important components of the osmotic defence response: Caprin2 and Creb3l1. METHODS By RNA in situ hybridization and immunohistochemistry, we have characterized the expression of Caprin2 and Creb3l1 in MCNs in the basal state, in response to dehydration, and during rehydration in the rat. RESULTS We found that Caprin2 and Creb3l1 are expressed in AVP and OXT MCNs and in response to dehydration expression increases in both MCN populations. Protein levels mirror the increase in transcript levels for both CREB3L1 and CAPRIN2. In view of increased CREB3L1 and CAPRIN2 expression in OXT neurones by dehydration, we explored OXT-specific functions for these genes. By luciferase assays, we demonstrate that CREB3L1 may be a transcription factor regulating Oxt gene expression. By RNA immunoprecipitation assays and Northern blot analysis of Oxt mRNA poly(A) tails, we have found that CAPRIN2 binds to Oxt mRNA and regulates its poly(A) tail length. Moreover, in response to dehydration, Caprin2 mRNA is subjected to nuclear retention, possibly to regulate Caprin2 mRNA availability in the cytoplasm. CONCLUSION The exploration of the spatiotemporal dynamics of Creb3l1- and Caprin2-encoded mRNAs and proteins has provided novel insights beyond the AVP-ergic system, revealing novel OXT-ergic system roles of these genes in the osmotic defence response.
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Affiliation(s)
- Soledad Bárez-López
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
| | - Agnieszka Konopacka
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
| | - Stephen J Cross
- Wolfson Bioimaging Facility, Biomedical Sciences Building, University of Bristol, Bristol, UK
| | - Mingkwan Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
| | - Marina Skarveli
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, UK
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Alvira-Iraizoz F, Gillard BT, Lin P, Paterson A, Pauža AG, Ali MA, Alabsi AH, Burger PA, Hamadi N, Adem A, Murphy D, Greenwood MP. Multiomic analysis of the Arabian camel (Camelus dromedarius) kidney reveals a role for cholesterol in water conservation. Commun Biol 2021; 4:779. [PMID: 34163009 PMCID: PMC8222267 DOI: 10.1038/s42003-021-02327-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 01/14/2021] [Accepted: 06/06/2021] [Indexed: 02/05/2023] Open
Abstract
The Arabian camel (Camelus dromedarius) is the most important livestock animal in arid and semi-arid regions and provides basic necessities to millions of people. In the current context of climate change, there is renewed interest in the mechanisms that enable camelids to survive in arid conditions. Recent investigations described genomic signatures revealing evolutionary adaptations to desert environments. We now present a comprehensive catalogue of the transcriptomes and proteomes of the dromedary kidney and describe how gene expression is modulated as a consequence of chronic dehydration and acute rehydration. Our analyses suggested an enrichment of the cholesterol biosynthetic process and an overrepresentation of categories related to ion transport. Thus, we further validated differentially expressed genes with known roles in water conservation which are affected by changes in cholesterol levels. Our datasets suggest that suppression of cholesterol biosynthesis may facilitate water retention in the kidney by indirectly facilitating the AQP2-mediated water reabsorption.
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Affiliation(s)
- Fernando Alvira-Iraizoz
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK.
| | - Benjamin T Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Panjiao Lin
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Mahmoud A Ali
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates
| | - Ammar H Alabsi
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Pamela A Burger
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, Vetmeduni Vienna, Vienna, Austria
| | - Naserddine Hamadi
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
| | - Abdu Adem
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates.
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
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Pauža AG, Mecawi AS, Paterson A, Hindmarch CCT, Greenwood M, Murphy D, Greenwood MP. Osmoregulation of the transcriptome of the hypothalamic supraoptic nucleus: A resource for the community. J Neuroendocrinol 2021; 33:e13007. [PMID: 34297454 DOI: 10.1111/jne.13007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 06/20/2021] [Indexed: 01/13/2023]
Abstract
The hypothalamic supraoptic nucleus (SON) is a core osmoregulatory control centre that deciphers information about the metabolic state of the organism and orchestrates appropriate homeostatic (endocrine) and allostatic (behavioural) responses. We have used RNA sequencing to describe the polyadenylated transcriptome of the SON of the male Wistar Han rat. These data have been mined to generate comprehensive catalogues of functional classes of genes (enzymes, transcription factors, endogenous peptides, G protein coupled receptors, transporters, catalytic receptors, channels and other pharmacological targets) expressed in this nucleus in the euhydrated state, and that together form the basal substrate for its physiological interactions. We have gone on to show that fluid deprivation for 3 days (dehydration) results in changes in the expression levels of 2247 RNA transcripts, which have similarly been functionally catalogued, and further mined to describe enriched gene categories and putative regulatory networks (Regulons) that may have physiological importance in SON function related plasticity. We hope that the revelation of these genes, pathways and networks, most of which have no characterised roles in the SON, will encourage the neuroendocrine community to pursue new investigations into the new 'known-unknowns' reported in the present study.
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Affiliation(s)
- Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - André Souza Mecawi
- Laboratory of Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
- Bristol Genomics Facility, University of Bristol, Bristol, UK
| | - Charles C T Hindmarch
- Queen's Cardiopulmonary Unit (QCPU), Department of Medicine, Translational Institute of Medicine (TIME), Queen's University, Kingston, ON, Canada
| | - Mingkwan Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
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15
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Dutra SGV, Paterson A, Monteiro LRN, Greenwood MP, Greenwood MP, Amaral LS, Melo MR, Colombari DSA, Colombari E, Reis LC, Hindmarch CCT, Elias LLK, Antunes-Rodrigues J, Murphy D, Mecawi AS. Physiological and Transcriptomic Changes in the Hypothalamic-Neurohypophysial System after 24 h of Furosemide-Induced Sodium Depletion. Neuroendocrinology 2021; 111:70-86. [PMID: 31955161 DOI: 10.1159/000505997] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/17/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Furosemide is a loop diuretic widely used in clinical practice for the treatment of oedema and hypertension. The aim of this study was to determine physiological and molecular changes in the hypothalamic-neurohypophysial system as a consequence of furosemide-induced sodium depletion. METHODS Male rats were sodium depleted by acute furosemide injection (10 and 30 mg/kg) followed by access to low sodium diet and distilled water for 24 h. The renal and behavioural consequences were evaluated, while blood and brains were collected to evaluate the neuroendocrine and gene expression responses. RESULTS Furosemide treatment acutely increases urinary sodium and water excretion. After 24 h, water and food intake were reduced, while plasma angiotensin II and corticosterone were increased. After hypertonic saline presentation, sodium-depleted rats showed higher preference for salt. Interrogation using RNA sequencing revealed the expression of 94 genes significantly altered in the hypothalamic paraventricular nucleus (PVN) of sodium-depleted rats (31 upregulated and 63 downregulated). Out of 9 genes chosen, 5 were validated by quantitative PCR in the PVN (upregulated: Ephx2, Ndnf and Vwf; downregulated: Caprin2 and Opn3). The same genes were also assessed in the supraoptic nucleus (SON, upregulated: Tnnt1, Mis18a, Nr1d1 and Dbp; downregulated: Caprin2 and Opn3). As a result of these plastic transcriptome changes, vasopressin expression was decreased in PVN and SON, whilst vasopressin and oxytocin levels were reduced in plasma. CONCLUSIONS We thus have identified novel genes that might regulate vasopressin gene expression in the hypothalamus controlling the magnocellular neurons secretory response to body sodium depletion and consequently hypotonic stress.
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Affiliation(s)
- Sabrina G V Dutra
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Translational Health Sciences, Bristol Medical School, Bristol, United Kingdom
| | - Livia R N Monteiro
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Translational Health Sciences, Bristol Medical School, Bristol, United Kingdom
| | - Mingkwan P Greenwood
- Molecular Neuroendocrinology Research Group, Translational Health Sciences, Bristol Medical School, Bristol, United Kingdom
| | - Ludimila S Amaral
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Mariana R Melo
- Department of Physiology and Pathology, School of Dentistry, UNESP, São Paulo State University, Araraquara, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, UNESP, São Paulo State University, Araraquara, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, UNESP, São Paulo State University, Araraquara, Brazil
| | - Luís C Reis
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Charles C T Hindmarch
- Queen's Cardiopulmonary Unit, Department of Medicine, Translational Institute of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Lucila L K Elias
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Translational Health Sciences, Bristol Medical School, Bristol, United Kingdom
| | - Andre S Mecawi
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil,
- Laboratory of Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil,
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Ali MA, Abu Damir H, Ali OM, Amir N, Tariq S, Greenwood MP, Lin P, Gillard B, Murphy D, Adem A. The effect of long-term dehydration and subsequent rehydration on markers of inflammation, oxidative stress and apoptosis in the camel kidney. BMC Vet Res 2020; 16:458. [PMID: 33228660 PMCID: PMC7686779 DOI: 10.1186/s12917-020-02628-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 02/13/2020] [Accepted: 10/19/2020] [Indexed: 12/24/2022] Open
Abstract
Background Dehydration has deleterious effects in many species, but camels tolerate long periods of water deprivation without serious health compromise. The kidney plays crucial role in water conservation, however, some reports point to elevated kidney function tests in dehydrated camels. In this work, we investigated the effects of dehydration and rehydration on kidney cortex and medulla with respect to pro-inflammatory markers, oxidative stress and apoptosis along with corresponding gene expression. Results The cytokines IL-1β and IL-18 levels were significantly elevated in the kidney cortex of dehydrated camel, possibly expressed by tubular epithelium, podocytes and/or mesangial cells. Elevation of IL-18 persisted after rehydration. Dehydration induced oxidative stress in kidney cortex evident by significant increases in MDA and GSH, but significant decreases in SOD and CAT. In the medulla, CAT decreased significantly, but MDA, GSH and SOD levels were not affected. Rehydration abolished the oxidative stress. In parallel with the increased levels of MDA, we observed increased levels of PTGS1 mRNA, in MDA synthesis pathway. GCLC mRNA expression level, involved in GSH synthesis, was upregulated in kidney cortex by rehydration. However, both SOD1 and SOD3 mRNA levels dropped, in parallel with SOD activity, in the cortex by dehydration. There were significant increases in caspases 3 and 9, p53 and PARP1, indicating apoptosis was triggered by intrinsic pathway. Expression of BCL2l1 mRNA levels, encoding for BCL-xL, was down regulated by dehydration in cortex. CASP3 expression level increased significantly in medulla by dehydration and continued after rehydration whereas TP53 expression increased in cortex by rehydration. Changes in caspase 8 and TNF-α were negligible to instigate extrinsic apoptotic trail. Generally, apoptotic markers were extremely variable after rehydration indicating that animals did not fully recover within three days. Conclusions Dehydration causes oxidative stress in kidney cortex and apoptosis in cortex and medulla. Kidney cortex and medulla were not homogeneous in all parameters investigated indicating different response to dehydration/rehydration. Some changes in tested parameters directly correlate with alteration in steady-state mRNA levels.
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Affiliation(s)
- Mahmoud A Ali
- Department of Pharmacology, CollegeofMedicine&HealthSciences, United Arab Emirates University, Al- Ain, United Arab Emirates
| | - Hassan Abu Damir
- Department of Pharmacology, CollegeofMedicine&HealthSciences, United Arab Emirates University, Al- Ain, United Arab Emirates
| | - Osman M Ali
- College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Naheed Amir
- Department of Pharmacology, CollegeofMedicine&HealthSciences, United Arab Emirates University, Al- Ain, United Arab Emirates
| | - Saeed Tariq
- Department of Anatomy, CollegeofMedicine&HealthSciences, Emirates University, Al-Ain, United Arab Emirates
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, BS13NY, UK
| | - Panjiao Lin
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, BS13NY, UK
| | - Benjamin Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, BS13NY, UK
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, BS13NY, UK.
| | - Abdu Adem
- Department of Pharmacology, CollegeofMedicine&HealthSciences, United Arab Emirates University, Al- Ain, United Arab Emirates. .,Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University, P.O.Box 127788, Abu Dhabi, UAE.
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Rhode C, Badenhorst R, Hull KL, Greenwood MP, Bester-van der Merwe AE, Andere AA, Picard CJ, Richards C. Genetic and phenotypic consequences of early domestication in black soldier flies (Hermetia illucens). Anim Genet 2020; 51:752-762. [PMID: 32524667 DOI: 10.1111/age.12961] [Citation(s) in RCA: 15] [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] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2020] [Indexed: 01/18/2023]
Abstract
The black soldier fly, Hermetia illucens, is an emerging biotechnological agent with its larvae being effective converters of organic waste into usable bio-products including protein and lipids. To date, most operations use unimproved commercial populations produced by mass rearing, without cognisance of specific breeding strategies. The genetic and phenotypic consequences of these commercial practices remain unknown and could have a significant impact on long-term population viability and productivity. The aim of this study was thus to assess the genetic and phenotypic changes during the early phases of colony establishment and domestication in the black soldier fly. An experimental colony was established from wild founder flies and a new microsatellite marker panel was developed to assess population genetic parameters along with the phenotypic characteristics of each generational cohort under captive breeding. The experimental colony was characterised by a small effective population size, subsequent loss of genetic diversity and rapid genetic and phenotypic differentiation between the generational cohorts. Ultimately, the population collapsed by the fifth generation, most likely owing to the adverse effect of inbreeding depression following the fixation of deleterious alleles. Species with r-selected life history characteristics (e.g. short life-span, high fecundity and low larval survival) are known to pose particular challenges for genetic management. The current study suggests that sufficient genetic and phenotypic variations exist in the wild population and that domestication and strain development could be achieved with careful population augmentation and selection during the early stages of colony establishment.
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Affiliation(s)
- C Rhode
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - R Badenhorst
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.,AgriProtein Holdings Ltd, 1 Farnham Road, Guildford, Surrey, GU2 4RG, UK
| | - K L Hull
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - M P Greenwood
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | | | - A A Andere
- Department of Biology, Purdue School of Science, Indiana University - University of Purdue Indianapolis, SL 306, 723 W Michigan Street, Indianapolis, IN, 46202, USA
| | - C J Picard
- Department of Biology, Purdue School of Science, Indiana University - University of Purdue Indianapolis, SL 306, 723 W Michigan Street, Indianapolis, IN, 46202, USA
| | - C Richards
- AgriProtein Holdings Ltd, 1 Farnham Road, Guildford, Surrey, GU2 4RG, UK
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Greenwood MP, DiPaola NR, Eagar TN. P144 Impact of low-level (MFI) HLA-antibodies on living donor kidney transplant rejection risk. Hum Immunol 2018. [DOI: 10.1016/j.humimm.2018.07.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Greenwood MP, Greenwood M, Romanova EV, Mecawi AS, Paterson A, Sarenac O, Japundžić-Žigon N, Antunes-Rodrigues J, Paton JFR, Sweedler JV, Murphy D. The effects of aging on biosynthetic processes in the rat hypothalamic osmoregulatory neuroendocrine system. Neurobiol Aging 2018; 65:178-191. [PMID: 29494864 PMCID: PMC5878011 DOI: 10.1016/j.neurobiolaging.2018.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 08/15/2016] [Revised: 07/11/2017] [Accepted: 01/16/2018] [Indexed: 11/21/2022]
Abstract
Elderly people exhibit a diminished capacity to cope with osmotic challenges such as dehydration. We have undertaken a detailed molecular analysis of arginine vasopressin (AVP) biosynthetic processes in the supraoptic nucleus (SON) of the hypothalamus and secretory activity in the posterior pituitary of adult (3 months) and aged (18 months) rats, to provide a comprehensive analysis of age-associated changes to the AVP system. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, we identified differences in pituitary peptides, including AVP, in adult and aged rats under both basal and dehydrated states. In the SON, increased Avp gene transcription, coincided with reduced Avp promoter methylation in aged rats. Based on transcriptome data, we have previously characterized a number of novel dehydration-induced regulatory factors involved in the response of the SON to osmotic cues. We found that some of these increase in expression with age, while dehydration-induced expression of these genes in the SON was attenuated in aged rats. In summary, we show that aging alters the rat AVP system at the genome, transcriptome, and peptidome levels. These alterations however did not affect circulating levels of AVP in basal or dehydrated states.
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Affiliation(s)
| | | | - Elena V Romanova
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Andre S Mecawi
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil; Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia; Department of Physiological Sciences, Institute of Biological and Health Sciênces, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - Alex Paterson
- School of Clinical Sciences, University of Bristol, Bristol, England
| | - Olivera Sarenac
- School of Clinical Sciences, University of Bristol, Bristol, England; Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nina Japundžić-Žigon
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Julian F R Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, England
| | - Jonathan V Sweedler
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, England; Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia
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Greenwood MP, Greenwood M, Gillard BT, Chitra Devi R, Murphy D. Regulation of cAMP Responsive Element Binding Protein 3-Like 1 (Creb3l1) Expression by Orphan Nuclear Receptor Nr4a1. Front Mol Neurosci 2017; 10:413. [PMID: 29311806 PMCID: PMC5732970 DOI: 10.3389/fnmol.2017.00413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 07/27/2017] [Accepted: 11/28/2017] [Indexed: 12/28/2022] Open
Abstract
Cyclic AMP (cAMP) inducible transcription factor cAMP responsive element binding protein 3 like 1 (Creb3l1) is strongly activated in the hypothalamus in response to hyperosmotic cues such as dehydration (DH). We have recently shown that Creb3l1 expression is upregulated by cAMP pathways in vitro, however the exact mechanisms are not known. Here we show that increasing Creb3l1 transcription by raising cAMP levels in mouse pituitary AtT20 cells automatically initiates cleavage of Creb3l1, leading to a greater abundance of the transcriptionally active N-terminal portion. Inhibiting protein synthesis indicated that de novo protein synthesis of an intermediary transcription factor was required for Creb3l1 induction. Strategic mining of our microarray data from dehydrated rodent hypothalamus revealed four candidates, reduced to two by analysis of acute hyperosmotic-induced transcriptional activation profiles in the hypothalamus, and one, orphan nuclear receptor Nr4a1, by direct shRNA mediated silencing in AtT20 cells. We show that activation of Creb3l1 transcription by Nr4a1 involves interaction with a single NBRE site in the promoter region. The ability to activate Creb3l1 transcription by this pathway in vitro is dictated by the level of methylation of a CpG island within the proximal promoter/5′UTR of this gene. We thus identify a novel cAMP-Nr4a1-Creb3l1 transcriptional pathway in AtT20 cells and also, our evidence would suggest, in the hypothalamus.
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Affiliation(s)
| | - Mingkwan Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Benjamin T Gillard
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - R Chitra Devi
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.,Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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21
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Silva MS, Lúcio-Oliveira F, Mecawi AS, Almeida LF, Ruginsk SG, Greenwood MP, Greenwood M, Vivas L, Elias LLK, Murphy D, Antunes-Rodrigues J. Increased exposure to sodium during pregnancy and lactation changes basal and induced behavioral and neuroendocrine responses in adult male offspring. Physiol Rep 2017; 5:5/6/e13210. [PMID: 28336818 PMCID: PMC5371570 DOI: 10.14814/phy2.13210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 02/13/2017] [Accepted: 02/20/2017] [Indexed: 12/24/2022] Open
Abstract
Excessive sodium (Na+) intake in modern society has been associated with several chronic disorders such as hypertension. Several studies suggest that early life events can program physiological systems and lead to functional changes in adulthood. Therefore, we investigated behavioral and neuroendocrine responses under basal conditions and after 48 h of water deprivation in adult (60‐day‐old Wistar rats) male, Wistar rats originating from dams were offered only water or 0.15 mol/L NaCl during pregnancy and lactation. Early life salt exposure induced kidney damage, as shown by a higher number of ED‐1 positive cells (macrophages/monocytes), increased daily urinary volume and Na+ excretion, blunted basal water intake and plasma oxytocin levels, and increased plasma corticosterone secretion. When challenged with water deprivation, animals exposed to 0.15 mol/L NaCl during early life showed impaired water intake, reduced salt preference ratio, and vasopressin (AVP) secretion. In summary, our data demonstrate that the perinatal exposure to excessive Na+ intake can induce kidney injury in adult offspring and significantly affect the key mechanisms regulating water balance, fluid intake, and AVP release in response to water deprivation. Collectively, these novel results highlight the impact of perinatal programming on the homeostatic mechanisms regulating fluid and electrolyte balance during exposure to an environmental stress (i.e. dehydration) in later life.
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Affiliation(s)
- Marcia S Silva
- Department of Physiology, School of Medicine of Ribeirao Preto University of Sao Paulo, Ribeirao Preto, São Paulo, Brazil
| | - Fabiana Lúcio-Oliveira
- Department of Physiology, School of Medicine of Ribeirao Preto University of Sao Paulo, Ribeirao Preto, São Paulo, Brazil
| | - Andre Souza Mecawi
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Physiological Sciences, Institute of Biology Federal Rural University of Rio de Janeiro, Rio de Janeiro, Seropedica, Brazil
| | - Lucas F Almeida
- Department of Physiology, School of Medicine of Ribeirao Preto University of Sao Paulo, Ribeirao Preto, São Paulo, Brazil
| | - Silvia G Ruginsk
- Departament of Physiological Sciences, Biomedical Sciences Institute, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil
| | | | - Mingkwan Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Laura Vivas
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET) Universidad Nacional de Córdoba, Córdoba, Argentina.,Facultad de Ciencias Exactas Físicas y Naturales Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirao Preto University of Sao Paulo, Ribeirao Preto, São Paulo, Brazil
| | - David Murphy
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Physiological Sciences, Institute of Biology Federal Rural University of Rio de Janeiro, Rio de Janeiro, Seropedica, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirao Preto University of Sao Paulo, Ribeirao Preto, São Paulo, Brazil
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22
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Lu W, Jin Y, Xu J, Greenwood MP, Balment RJ. Molecular characterisation and expression of parathyroid hormone-related protein in the caudal neurosecretory system of the euryhaline flounder, Platichthys flesus. Gen Comp Endocrinol 2017; 249:24-31. [PMID: 28242308 DOI: 10.1016/j.ygcen.2017.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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: 07/07/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 02/05/2023]
Abstract
Parathyroid hormone-related protein (PTHrP) is a hypercalcemic factor in fish, but the source of circulating PTHrP remains unclear. In this study investigation of the caudal neurosecretory system (CNSS), considered one of major sources of PTHrP in fish, provided valuable insights into this regulatory system. We report pthrpa and pthrpb gene cloning, characterization, expression, and responses to low salinity and hypocalcemia challenge in flounder. The pthrpa and pthrpb precursors, isolated from a European flounder CNSS library, consist of 166 and 192 amino acid residues, respectively, with an overall homology of approximately 59.2%. Both precursors contain a signal peptide and a mature peptide with cleavage and amidation sites. The flounder PTHrPA and PTHrPB peptides share only 41% sequence identity with human PTHrPA. Quantitative PCR analysis demonstrated that the bone and bladder, are respectively major sites of pthrpa and pthrpb expression in flounder. Urophysectomy confirmed the CNSS as a likely contributor to circulating PTHrP peptides. There were no significant differences in CNSS pthrpa and pthrpb mRNA expression or plasma PTHrP levels between seawater (SW) and freshwater (FW)-adapted fish, though plasma total calcium concentrations were higher in FW animals. The intraperitonial administration of EGTA rapidly induced hypocalcemia and concomitant elevation in plasma PTHrP accompanied by increases in both pthrpa and pthrpb expression in the CNSS. Together, these findings support an evolutionary conserved role for PTHrP in the endocrine regulation of calcium.
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Affiliation(s)
- Weiqun Lu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai 201306, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China.
| | - Yingying Jin
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
| | - Jinling Xu
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
| | - Michael P Greenwood
- Faculty of Life Sciences, University of Manchester, Oxford Road, M13 9PT, United Kingdom
| | - Richard J Balment
- Faculty of Life Sciences, University of Manchester, Oxford Road, M13 9PT, United Kingdom
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Greenwood MP, Greenwood M, Gillard BT, Loh SY, Paton JFR, Murphy D. Epigenetic Control of the Vasopressin Promoter Explains Physiological Ability to Regulate Vasopressin Transcription in Dehydration and Salt Loading States in the Rat. J Neuroendocrinol 2016; 28. [PMID: 26833868 PMCID: PMC4855680 DOI: 10.1111/jne.12371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/06/2016] [Accepted: 01/23/2016] [Indexed: 02/06/2023]
Abstract
The synthesis of arginine vasopressin (AVP) in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus is sensitive to increased plasma osmolality and a decreased blood volume, and thus is robustly increased by both dehydration (increased plasma osmolality and decreased blood volume) and salt loading (increased plasma osmolality). Both stimuli result in functional remodelling of the SON and PVN, a process referred to as functional-related plasticity. Such plastic changes in the brain have recently been associated with altered patterns of DNA methylation at CpG (cytosine-phosphate-guanine) residues, a process considered to be important for the regulation of gene transcription. In this regard, the proximal Avp promoter contains a number of CpG sites and is recognised as one of four CpG islands for the Avp gene, suggesting that methylation may be regulating Avp transcription. In the present study, we show that, in an immortalised hypothalamic cell line 4B, the proximal Avp promoter is highly methylated, and treatment of these cells with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine to demethylate DNA dramatically increases basal and stimulated Avp biosynthesis. We report no changes in the expression of DNA methyltransferases, Dnmt1 and Dnmt3a, whereas there is decreased expression of the demethylating enzyme ten-eleven-translocation 2, Tet2, in the SON by dehydration and salt loading. We found higher methylation of the SON Avp promoter in dehydrated but not salt-loaded rats. By analysis of individual CpG sites, we observed hypomethylation, hypermethylation and no change in methylation of specific CpGs in the SON Avp promoter of the dehydrated rat. Using reporter gene assays, we show that mutation of individual CpGs can result in altered Avp promoter activity. We propose that methylation of the SON Avp promoter is necessary to co-ordinate the duel inputs of increased plasma osmolality and decreased blood volume on Avp transcription in the chronically dehydrated rat.
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Affiliation(s)
- M P Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, UK
| | - M Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, UK
| | - B T Gillard
- School of Clinical Sciences, University of Bristol, Bristol, UK
| | - S Y Loh
- Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia
| | - J F R Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - D Murphy
- School of Clinical Sciences, University of Bristol, Bristol, UK
- Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia
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24
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Greenwood MP, Greenwood M, Mecawi AS, Antunes-Rodrigues J, Paton JFR, Murphy D. Rasd1, a small G protein with a big role in the hypothalamic response to neuronal activation. Mol Brain 2016; 9:1. [PMID: 26739966 PMCID: PMC4704412 DOI: 10.1186/s13041-015-0182-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/23/2015] [Indexed: 12/28/2022] Open
Abstract
Background Rasd1 is a member of the Ras family of monomeric G proteins that was first identified as a dexamethasone inducible gene in the pituitary corticotroph cell line AtT20. Using microarrays we previously identified increased Rasd1 mRNA expression in the rat supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus in response to increased plasma osmolality provoked by fluid deprivation and salt loading. RASD1 has been shown to inhibit adenylyl cyclase activity in vitro resulting in the inhibition of the cAMP-PKA-CREB signaling pathway. Therefore, we tested the hypothesis that RASD1 may inhibit cAMP stimulated gene expression in the brain. Results We show that Rasd1 is expressed in vasopressin neurons of the PVN and SON, within which mRNA levels are induced by hyperosmotic cues. Dexamethasone treatment of AtT20 cells decreased forskolin stimulation of c-Fos, Nr4a1 and phosphorylated CREB expression, effects that were mimicked by overexpression of Rasd1, and inhibited by knockdown of Rasd1. These effects were dependent upon isoprenylation, as both farnesyltransferase inhibitor FTI-277 and CAAX box deletion prevented Rasd1 inhibition of cAMP-induced gene expression. Injection of lentiviral vector into rat SON expressing Rasd1 diminished, whereas CAAX mutant increased, cAMP inducible genes in response to osmotic stress. Conclusions We have identified two mechanisms of Rasd1 induction in the hypothalamus, one by elevated glucocorticoids in response to stress, and one in response to increased plasma osmolality resulting from osmotic stress. We propose that the abundance of RASD1 in vasopressin expressing neurons, based on its inhibitory actions on CREB phosphorylation, is an important mechanism for controlling the transcriptional responses to stressors in both the PVN and SON. These effects likely occur through modulation of cAMP-PKA-CREB signaling pathway in the brain.
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Affiliation(s)
| | - Mingkwan Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, BS1 3NY, UK.
| | - Andre S Mecawi
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. .,Department of Physiology, University of Malaya, Kuala Lumpur, 50603, Malaysia. .,Department of Physiological Sciences, Biology Institute, Federal Rural University of Rio de Janeiro, Seropedica, Rio de Janeiro, Brazil.
| | | | - Julian F R Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK.
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, BS1 3NY, UK. .,Department of Physiology, University of Malaya, Kuala Lumpur, 50603, Malaysia.
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25
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Greenwood M, Greenwood MP, Mecawi AS, Loh SY, Rodrigues JA, Paton JFR, Murphy D. Transcription factor CREB3L1 mediates cAMP and glucocorticoid regulation of arginine vasopressin gene transcription in the rat hypothalamus. Mol Brain 2015; 8:68. [PMID: 26503226 PMCID: PMC4624382 DOI: 10.1186/s13041-015-0159-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/18/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Arginine vasopressin (AVP), a neuropeptide hormone that functions in the regulation of water homeostasis by controlling water re-absorption at kidneys, is synthesised in supraoptic nucleus and paraventricular nucleus of the hypothalamus. An increase in plasma osmolality stimulates secretion of AVP to blood circulation and induces AVP synthesis in these nuclei. Although studies on mechanism of AVP transcriptional regulation in hypothalamus proposed that cAMP and glucocorticoids positively and negatively regulate Avp expression, respectively, the molecular mechanisms have remained elusive. Recently, we identified CREB3L1 (cAMP-responsive element binding protein 3 like 1) as a putative transcription factor of Avp transcription in the rat hypothalamus. However the mechanism of how CREB3L1 is regulated in response of hyperosmotic stress in the neurons of hypothalamus has never been reported. This study aims to investigate effect of previously reported regulators (cAMP and glucocorticoid) of Avp transcription on transcription factor CREB3L1 in order to establish a molecular explanation for cAMP and glucocorticoids effect on AVP expression. RESULTS The effect of cAMP and glucocorticoid treatment on Creb3l1 was investigated in both AtT20 cells and hypothalamic organotypic cultures. The expression of Creb3l1 was increased in both mRNA and protein level by treatment with forskolin, which raises intracellular cAMP levels. Activation of cAMP by forskolin also increased Avp promoter activity in AtT20 cells and this effect was blunted by shRNA mediated silencing of Creb3l1. The forskolin induced increase in Creb3l1 expression was diminished by combined treatment with dexamethasone, and, in vivo, intraperitoneal dexamethasone injection blunted the increase in Creb3l1 and Avp expression induced by hyperosmotic stress. CONCLUSION Here we shows that cAMP and glucocorticoid positively and negatively regulate Creb3l1 expression in the rat hypothalamus, respectively, and regulation of cAMP on AVP expression is mediated through CREB3L1. This data provides the connection between CREB3L1, a newly identified transcription factor of AVP expression, with the previously proposed mechanism of Avp transcription which extends our understanding in transcription regulation of Avp in the hypothalamus.
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Affiliation(s)
- Mingkwan Greenwood
- School of Clinical Sciences, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, England.
| | - Michael P Greenwood
- School of Clinical Sciences, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, England.
| | - Andre S Mecawi
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. .,Department of Physiology, University of Malaya, Kuala Lumpur, 50603, Malaysia. .,Department of Physiological Sciences, Biology Institute, Federal Rural University of Rio de Janeiro, Seropedica, Rio de Janeiro, Brazil.
| | - Su Yi Loh
- Department of Physiology, University of Malaya, Kuala Lumpur, 50603, Malaysia.
| | | | - Julian F R Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, England.
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, England. .,Department of Physiology, University of Malaya, Kuala Lumpur, 50603, Malaysia.
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26
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Greenwood MP, Greenwood M, Paton JFR, Murphy D. Control of Polyamine Biosynthesis by Antizyme Inhibitor 1 Is Important for Transcriptional Regulation of Arginine Vasopressin in the Male Rat Hypothalamus. Endocrinology 2015; 156:2905-17. [PMID: 25961839 PMCID: PMC4511134 DOI: 10.1210/en.2015-1074] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The polyamines spermidine and spermine are small cations present in all living cells. In the brain, these cations are particularly abundant in the neurons of the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus, which synthesize the neuropeptide hormones arginine vasopressin (AVP) and oxytocin. We recently reported increased mRNA expression of antizyme inhibitor 1 (Azin1), an important regulator of polyamine synthesis, in rat SON and PVN as a consequence of 3 days of dehydration. Here we show that AZIN1 protein is highly expressed in both AVP- and oxytocin-positive magnocellular neurons of the SON and PVN together with antizyme 1 (AZ1), ornithine decarboxylase, and polyamines. Azin1 mRNA expression increased in the SON and PVN as a consequence of dehydration, salt loading, and acute hypertonic stress. In organotypic hypothalamic cultures, addition of the irreversible ornithine decarboxylase inhibitor DL-2-(difluoromethyl)-ornithine hydrochloride significantly increased the abundance of heteronuclear AVP but not heteronuclear oxytocin. To identify the function of Azin1 in vivo, lentiviral vectors that either overexpress or knock down Azin1 were stereotaxically delivered into the SON and/or PVN. Azin1 short hairpin RNA delivery resulted in decreased plasma osmolality and had a significant effect on food intake. The expression of AVP mRNA was also significantly increased in the SON by Azin1 short hairpin RNA. In contrast, Azin1 overexpression in the SON decreased AVP mRNA expression. We have therefore identified AZIN1, and hence by inference, polyamines as novel regulators of the expression of the AVP gene.
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Affiliation(s)
- Michael P Greenwood
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Mingkwan Greenwood
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Julian F R Paton
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - David Murphy
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
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27
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Abstract
Situations encountered on-call often bring some of the most unique and educationally rich questions to a pathology resident's attention which can be difficult to incorporate into institutional memory. A searchable online site (wiki) provides an easily accessible platform by which to do this and could serve as a valuable after-hour resident resource. Therefore, we evaluated a wiki's usefulness by creating a wiki using Campuspack for residents to catalog uncommon questions/situations encountered on call or rotations. After 41 months in use, analytic software embedded in the site was queried for usage statistics and one year's cohort of residents was surveyed to assess the wiki's value. Since the sites inception, over 7200 individual interactions with the site were recorded, with June through August being the most active period each year. Of the 15 residents surveyed, 60% utilized the site to answer a clinical question at least monthly and the majority (93%) considered the wiki a valuable on call resource. These findings suggest that an on-call wiki is a convenient tool for capturing the unique situations that pathology residents encounter. The majority of residents find the site a valuable resource and utilize it to answer clinical questions.
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Affiliation(s)
- Michael P Greenwood
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Geoffrey A Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
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28
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Greenwood MP, Mecawi AS, Hoe SZ, Mustafa MR, Johnson KR, Al-Mahmoud GA, Elias LLK, Paton JFR, Antunes-Rodrigues J, Gainer H, Murphy D, Hindmarch CCT. A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus. Am J Physiol Regul Integr Comp Physiol 2015; 308:R559-68. [PMID: 25632023 DOI: 10.1152/ajpregu.00444.2014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/21/2015] [Indexed: 01/16/2023]
Abstract
Salt loading (SL) and water deprivation (WD) are experimental challenges that are often used to study the osmotic circuitry of the brain. Central to this circuit is the supraoptic nucleus (SON) of the hypothalamus, which is responsible for the biosynthesis of the hormones, arginine vasopressin (AVP) and oxytocin (OXT), and their transport to terminals that reside in the posterior lobe of the pituitary. On osmotic challenge evoked by a change in blood volume or osmolality, the SON undergoes a function-related plasticity that creates an environment that allows for an appropriate hormone response. Here, we have described the impact of SL and WD compared with euhydrated (EU) controls in terms of drinking and eating behavior, body weight, and recorded physiological data including circulating hormone data and plasma and urine osmolality. We have also used microarrays to profile the transcriptome of the SON following SL and remined data from the SON that describes the transcriptome response to WD. From a list of 2,783 commonly regulated transcripts, we selected 20 genes for validation by qPCR. All of the 9 genes that have already been described as expressed or regulated in the SON by osmotic stimuli were confirmed in our models. Of the 11 novel genes, 5 were successfully validated while 6 were false discoveries.
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Affiliation(s)
| | - Andre S Mecawi
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - See Ziau Hoe
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Rais Mustafa
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kory R Johnson
- Clinical Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Ghada A Al-Mahmoud
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Al Tarfa, Doha, Qatar
| | - Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Julian F R Paton
- School of Physiology and Pharmacology, University Walk, Bristol, United Kingdom; and
| | - Jose Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom; Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Charles C T Hindmarch
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom; Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia;
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29
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Li XF, Hu MH, Li SY, Geach C, Hikima A, Rose S, Greenwood MP, Greenwood M, Murphy D, Poston L, Lightman SL, O'Byrne KT. Overexpression of corticotropin releasing factor in the central nucleus of the amygdala advances puberty and disrupts reproductive cycles in female rats. Endocrinology 2014; 155:3934-44. [PMID: 25051447 DOI: 10.1210/en.2014-1339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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
Prolonged exposure to environmental stress activates the hypothalamic-pituitary-adrenal (HPA) axis and generally disrupts the hypothalamic-pituitary-gonadal axis. Because CRF expression in the central nucleus of the amygdala (CeA) is a key modulator in adaptation to chronic stress, and central administration of CRF inhibits the hypothalamic GnRH pulse generator, we tested the hypothesis that overexpression of CRF in the CeA of female rats alters anxiety behavior, dysregulates the HPA axis response to stress, changes pubertal timing, and disrupts reproduction. We used a lentiviral vector to increase CRF expression site specifically in the CeA of preweaning (postnatal day 12) female rats. Overexpression of CRF in the CeA increased anxiety-like behavior in peripubertal rats shown by a reduction in time spent in the open arms of the elevated plus maze and a decrease in social interaction. Paradoxically, puberty onset was advanced but followed by irregular estrous cyclicity and an absence of spontaneous preovulatory LH surges associated with proestrous vaginal cytology in rats overexpressing CRF. Despite the absence of change in basal corticosterone secretion or induced by stress (lipopolysaccharide or restraint), overexpression of CRF in the CeA significantly decreased lipopolysaccharide, but not restraint, stress-induced suppression of pulsatile LH secretion in postpubertal ovariectomized rats, indicating a differential stress responsivity of the GnRH pulse generator to immunological stress and a potential adaptation of the HPA axis to chronic activation of amygdaloid CRF. These data suggest that the expression profile of this key limbic brain CRF system might contribute to the complex neural mechanisms underlying the increasing incidence of early onset of puberty on the one hand and infertility on the other attributed to chronic stress in modern human society.
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Affiliation(s)
- X F Li
- Division of Women's Health (X.F.L., M.H.H., S.Y.L., C.G., L.P., K.T.O.) and Neurodegenerative Disease Research Group (A.H., S.R.), School of Medicine, King's College London, Guy's Campus, London SE1 1UL, United Kingdom; and Henry Wellcome Laboratory for Integrative Neuroscience and Endocrinology (M.P.G., M.G., D.M., S.L.L.), University of Bristol, Bristol BS13NY, United Kingdom
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30
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Greenwood MP, Flik G, Wagner GF, Balment RJ. The corpuscles of Stannius, calcium-sensing receptor, and stanniocalcin: responses to calcimimetics and physiological challenges. Endocrinology 2009; 150:3002-10. [PMID: 19299449 PMCID: PMC2703514 DOI: 10.1210/en.2008-1758] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [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
This study has examined whether the calcium-sensing receptor (CaSR) plays a role in control of stanniocalcin-1 (STC-1), the dominant calcium regulatory hormone of fish, comparable with that demonstrated for CaSR in the mediation of ionized calcium regulation of PTH secretion in mammals. In a previous study, we have cloned flounder STC-1 from the corpuscles of Stannius (CS). Here, we report the cloning and characterization of the CS CaSR, and the in vivo responses of this system to altered salinity, EGTA induced hypocalcemia, and calcimimetic administration. Quantitative PCR analysis demonstrated, for the first time, that the CS are major sites of CaSR expression in flounder. Immunoblot analysis of CS proteins with CaSR-specific antibodies revealed a broad band of approximately 215-300 kDa under nonreducing conditions, and bands of approximately 215-300 kDa and approximately 120-150 kDa under reducing conditions. There were no differences in CS CaSR mRNA expression or plasma STC-1 levels between seawater and freshwater (FW)-adapted fish, although CS STC-1 mRNA expression was lower in FW animals. Immunoblots showed that glycosylated monomeric forms of the CaSR migrated at a lower molecular mass in CS samples from FW animals. The ip administration of EGTA rapidly induced hypocalcemia, and a concomitant lowering of plasma STC-1. Calcimimetic administration (1 mg/kg R-568) rapidly increased plasma STC-1 levels, and reduced plasma concentrations of calcium, phosphate, and magnesium when compared with S-568-treated controls. Together, these findings support an evolutionary conserved role for the CaSR in the endocrine regulation of calcium before the appearance of parathyroid glands in tetrapods.
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Affiliation(s)
- Michael P Greenwood
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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