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Lindberg I, Shu Z, Lam H, Helwig M, Yucer N, Laperle A, Svendsen C, Di Monte DA, Maidment NT. The proSAAS Chaperone Provides Neuroprotection and Attenuates Transsynaptic α-Synuclein Spread in Rodent Models of Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2022; 12:1463-1478. [PMID: 35527562 PMCID: PMC9731515 DOI: 10.3233/jpd-213053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Parkinson's disease involves aberrant aggregation of the synaptic protein alpha-synuclein (aSyn) in the nigrostriatal tract. We have previously shown that proSAAS, a small neuronal chaperone, blocks aSyn-induced dopaminergic cytotoxicity in primary nigral cultures. OBJECTIVE To determine if proSAAS overexpression is neuroprotective in animal models of Parkinson's disease. METHODS proSAAS- or GFP-encoding lentivirus was injected together with human aSyn-expressing AAV unilaterally into the substantia nigra of rats and motor asymmetry assessed using a battery of motor performance tests. Dopamine neuron survival was assessed by nigral stereology and striatal tyrosine hydroxylase (TH) densitometry. To examine transsynaptic spread of aSyn, aSyn AAV was injected into the vagus of mice in the presence of AAVs encoding either GFP or proSAAS; the spread of aSyn-positive neurites into rostral nuclei was quantified following immunohistochemistry. RESULTS Coinjection of proSAAS-encoding lentivirus profoundly reduced the motor asymmetry caused by unilateral nigral AAV-mediated human aSyn overexpression. This was accompanied by significant amelioration of the human aSyn-induced loss of both nigral TH-positive cells and striatal TH-positive terminals, demonstrating clear proSAAS-mediated protection of the nigrostriatal tract. ProSAAS overexpression reduced human aSyn protein levels in nigra and striatum and reduced the loss of TH protein in both regions. Following vagal administration of human aSyn-encoding AAV, the number of human aSyn-positive neurites in the pons and caudal midbrain was considerably reduced in mice coinjected with proSAAS-, but not GFP-encoding AAV, supporting proSAAS-mediated blockade of transsynaptic aSyn transmission. CONCLUSION The proSAAS chaperone may represent a promising target for therapeutic development in Parkinson's disease.
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Affiliation(s)
- Iris Lindberg
- University of Maryland-Baltimore;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
| | - Zhan Shu
- University of California-Los Angeles
| | - Hoa Lam
- University of California-Los Angeles
| | | | - Nur Yucer
- Cedars-Sinai Medical Center, Los Angeles
| | | | | | | | - Nigel T. Maidment
- University of California-Los Angeles;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
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Shakya M, Yildirim T, Lindberg I. Increased expression and retention of the secretory chaperone proSAAS following cell stress. Cell Stress Chaperones 2020; 25:929-941. [PMID: 32607937 PMCID: PMC7591655 DOI: 10.1007/s12192-020-01128-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 11/25/2022] Open
Abstract
The secretory pathway of neurons and endocrine cells contains a variety of mechanisms designed to combat cellular stress. These include not only the unfolded protein response pathways but also diverse chaperone proteins that collectively work to ensure proteostatic control of secreted and membrane-bound molecules. One of the least studied of these chaperones is the neural- and endocrine-specific molecule known as proSAAS. This small chaperone protein acts as a potent anti-aggregant both in vitro and in cellulo and also represents a cerebrospinal fluid biomarker in Alzheimer's disease. In the present study, we have examined the idea that proSAAS, like other secretory chaperones, might represent a stress-responsive protein. We find that exposure of neural and endocrine cells to the cell stressors tunicamycin and thapsigargin increases cellular proSAAS mRNA and protein in Neuro2A cells. Paradoxically, proSAAS secretion is inhibited by these same drugs. Exposure of Neuro2A cells to low concentrations of the hypoxic stress inducer cobalt chloride, or to sodium arsenite, an oxidative stressor, also increases cellular proSAAS content and reduces its secretion. We conclude that the cellular levels of the small secretory chaperone proSAAS are positively modulated by cell stress.
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Affiliation(s)
- Manita Shakya
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St, HSF2, S267, Baltimore, MD, 21201, USA
| | - Taha Yildirim
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St, HSF2, S267, Baltimore, MD, 21201, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St, HSF2, S267, Baltimore, MD, 21201, USA.
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Atkins N, Ren S, Hatcher N, Burgoon PW, Mitchell JW, Sweedler JV, Gillette MU. Functional Peptidomics: Stimulus- and Time-of-Day-Specific Peptide Release in the Mammalian Circadian Clock. ACS Chem Neurosci 2018; 9:2001-2008. [PMID: 29901982 DOI: 10.1021/acschemneuro.8b00089] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Daily oscillations of brain and body states are under complex temporal modulation by environmental light and the hypothalamic suprachiasmatic nucleus (SCN), the master circadian clock. To better understand mediators of differential temporal modulation, we characterize neuropeptide releasate profiles by nonselective capture of secreted neuropeptides in an optic nerve horizontal SCN brain slice model. Releasates are collected following electrophysiological stimulation of the optic nerve/retinohypothalamic tract under conditions that alter the phase of the SCN activity state. Secreted neuropeptides are identified by intact mass via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We found time-of-day-specific suites of peptides released downstream of optic nerve stimulation. Peptide release was modified differentially with respect to time-of-day by stimulus parameters and by inhibitors of glutamatergic or PACAPergic neurotransmission. The results suggest that SCN physiology is modulated by differential peptide release of both known and unexpected peptides that communicate time-of-day-specific photic signals via previously unreported neuropeptide signatures.
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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] [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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Ali MA, Kazzam E, Amir N, Nyberg F, Adem A. Effects of dehydration and blockade of angiotensin II AT1 receptor on stress hormones and anti-oxidants in the one-humped camel. BMC Vet Res 2013; 9:232. [PMID: 24252635 PMCID: PMC4225509 DOI: 10.1186/1746-6148-9-232] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/08/2013] [Indexed: 01/18/2023] Open
Abstract
Background The objective of this study was to provide for the first time data on plasma catecholamines, cortisol, glutathione and malondialdehyde after long term dehydration (20 days) in the presence and absence of angiotensin II (Ang II) AT1 receptor blocker (losartan) versus levels in time-matched, non-dehydrated control camels and to record the responses of glutathione and malondialdehyde activity in liver and kidney homogenates in control, dehydrated-losartan treated and dehydrated camels. Eighteen male camels were studied, six hydrated (control group), six dehydrated and treated with losartan (treated group) and six dehydrated not treated (dehydrated). Results Plasma levels of norepinephrine and dopamine were significantly increased (P < 0.01) in both treated and dehydrated groups compared to time matched control, whereas Plasma epinephrine level showed significant decrease (P < 0.05) in both treated and dehydrated groups compared to control. Plasma cortisol also showed significant increase (P < 0.01) in both treated and dehydrated groups compared to control. Glutathione levels in plasma, liver and kidney homogenates for both treated and dehydrated groups reveled significant increase (P < 0.05) Likewise, malondialdehyde levels in plasma, liver and kidney homogenates were substantially and significantly increased in both treated and dehydrated groups. Conclusion In conclusion, the results of this study demonstrated that dehydration substantially increased the circulating levels of norepinephrine, dopamine and cortisol but decreased plasma epinephrine. Similarly, losartan showed similar effects to that of dehydration. In addition, this investigation showed dehydration alone or in combination with losartan induced significant increments in glutathione and malondialdehyde activities in plasma, liver and kidney homogenates, presumably in order to counteract the potentially damaging effects of free radicals. Blockade of angiotensin II AT1 receptors did not alter significantly the response of dehydration in any of these indices.
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Affiliation(s)
- Mahmoud Alhaj Ali
- Department of Pharmacology and Therapeutics, Faculty of Medicine and Health Sciences, United Arab Emirates University, P,O, Box 17666, Al Ain, United Arab Emirates.
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Karlsson O, Berg AL, Lindström AK, Hanrieder J, Arnerup G, Roman E, Bergquist J, Lindquist NG, Brittebo EB, Andersson M. Neonatal exposure to the cyanobacterial toxin BMAA induces changes in protein expression and neurodegeneration in adult hippocampus. Toxicol Sci 2012; 130:391-404. [PMID: 22872059 PMCID: PMC3498744 DOI: 10.1093/toxsci/kfs241] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The cyanobacterial toxin β-N-methylamino-l-alanine (BMAA) has been proposed to contribute to neurodegenerative disease. We have previously reported a selective uptake of BMAA in the mouse neonatal hippocampus and that exposure during the neonatal period causes learning and memory impairments in adult rats. The aim of this study was to characterize effects in the brain of 6-month-old rats treated neonatally (postnatal days 9–10) with the glutamatergic BMAA. Protein changes were examined using the novel technique Matrix-Assisted Laser Desorption Ionization (MALDI) imaging mass spectrometry (IMS) for direct imaging of proteins in brain cryosections, and histological changes were examined using immunohistochemistry and histopathology. The results showed long-term changes including a decreased expression of proteins involved in energy metabolism and intracellular signaling in the adult hippocampus at a dose (150mg/kg) that gave no histopathological lesions in this brain region. Developmental exposure to a higher dose (460mg/kg) also induced changes in the expression of S100β, histones, calcium- and calmodulin-binding proteins, and guanine nucleotide-binding proteins. At this dose, severe lesions in the adult hippocampus including neuronal degeneration, cell loss, calcium deposits, and astrogliosis were evident. The data demonstrate subtle, sometimes dose-dependent, but permanent effects of a lower neonatal dose of BMAA in the adult hippocampus suggesting that BMAA could potentially disturb many processes during the development. The detection of BMAA in seafood stresses the importance of evaluating the magnitude of human exposure to this neurotoxin.
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Affiliation(s)
- Oskar Karlsson
- Department of Pharmaceutical Biosciences, Uppsala University, 75124 Uppsala, Sweden.
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Laurindo FRM, Pescatore LA, Fernandes DDC. Protein disulfide isomerase in redox cell signaling and homeostasis. Free Radic Biol Med 2012; 52:1954-69. [PMID: 22401853 DOI: 10.1016/j.freeradbiomed.2012.02.037] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 12/16/2022]
Abstract
Thiol proteins may potentially act as redox signaling adaptor proteins, adjusting reactive oxygen species intermediates to specific signals and redox signals to cell homeostasis. In this review, we discuss redox effects of protein disulfide isomerase (PDI), a thioredoxin superfamily oxidoreductase from the endoplasmic reticulum (ER). Abundantly expressed PDI displays ubiquity, interactions with redox and nonredox proteins, versatile effects, and several posttranslational modifications. The PDI family contains >20 members with at least some apparent complementary actions. PDI has oxidoreductase, isomerase, and chaperone effects, the last not directly dependent on its thiols. PDI is a converging hub for pathways of disulfide bond introduction into ER-processed proteins, via hydrogen peroxide-generating mechanisms involving the oxidase Ero1α, as well as hydrogen peroxide-consuming reactions involving peroxiredoxin IV and the novel peroxidases Gpx7/8. PDI is a candidate pathway for coupling ER stress to oxidant generation. Emerging information suggests a convergence between PDI and Nox family NADPH oxidases. PDI silencing prevents Nox responses to angiotensin II and inhibits Akt phosphorylation in vascular cells and parasite phagocytosis in macrophages. PDI overexpression spontaneously enhances Nox activation and expression. In neutrophils, PDI redox-dependently associates with p47phox and supports the respiratory burst. At the cell surface, PDI exerts transnitrosation, thiol reductase, and apparent isomerase activities toward targets including adhesion and matrix proteins and proteases. Such effects mediate redox-dependent adhesion, coagulation/thrombosis, immune functions, and virus internalization. The route of PDI externalization remains elusive. Such multiple redox effects of PDI may contribute to its conspicuous expression and functional role in disease, rendering PDI family members putative redox cell signaling adaptors.
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Affiliation(s)
- Francisco R M Laurindo
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, 05403-000 São Paulo, Brazil.
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Murphy D, Konopacka A, Hindmarch C, Paton JFR, Sweedler JV, Gillette MU, Ueta Y, Grinevich V, Lozic M, Japundzic-Zigon N. The hypothalamic-neurohypophyseal system: from genome to physiology. J Neuroendocrinol 2012; 24:539-53. [PMID: 22448850 PMCID: PMC3315060 DOI: 10.1111/j.1365-2826.2011.02241.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The elucidation of the genomes of a large number of mammalian species has produced a huge amount of data on which to base physiological studies. These endeavours have also produced surprises, not least of which has been the revelation that the number of protein coding genes needed to make a mammal is only 22 333 (give or take). However, this small number belies an unanticipated complexity that has only recently been revealed as a result of genomic studies. This complexity is evident at a number of levels: (i) cis-regulatory sequences; (ii) noncoding and antisense mRNAs, most of which have no known function; (iii) alternative splicing that results in the generation of multiple, subtly different mature mRNAs from the precursor transcript encoded by a single gene; and (iv) post-translational processing and modification. In this review, we examine the steps being taken to decipher genome complexity in the context of gene expression, regulation and function in the hypothalamic-neurohypophyseal system (HNS). Five unique stories explain: (i) the use of transcriptomics to identify genes involved in the response to physiological (dehydration) and pathological (hypertension) cues; (ii) the use of mass spectrometry for single-cell level identification of biological active peptides in the HNS, and to measure in vitro release; (iii) the use of transgenic lines that express fusion transgenes enabling (by cross-breeding) the generation of double transgenic lines that can be used to study vasopressin (AVP) and oxytocin (OXT) neurones in the HNS, as well as their neuroanatomy, electrophysiology and activation upon exposure to any given stimulus; (iv) the use of viral vectors to demonstrate that somato-dendritically released AVP plays an important role in cardiovascular homeostasis by binding to V1a receptors on local somata and dendrites; and (v) the use of virally-mediated optogenetics to dissect the role of OXT and AVP in the modulation of a wide variety of behaviours.
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Affiliation(s)
- D Murphy
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK.
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Atkins N, Mitchell JW, Romanova EV, Morgan DJ, Cominski TP, Ecker JL, Pintar JE, Sweedler JV, Gillette MU. Circadian integration of glutamatergic signals by little SAAS in novel suprachiasmatic circuits. PLoS One 2010; 5:e12612. [PMID: 20830308 PMCID: PMC2935382 DOI: 10.1371/journal.pone.0012612] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 08/03/2010] [Indexed: 12/03/2022] Open
Abstract
Background Neuropeptides are critical integrative elements within the central circadian clock in the suprachiasmatic nucleus (SCN), where they mediate both cell-to-cell synchronization and phase adjustments that cause light entrainment. Forward peptidomics identified little SAAS, derived from the proSAAS prohormone, among novel SCN peptides, but its role in the SCN is poorly understood. Methodology/Principal Findings Little SAAS localization and co-expression with established SCN neuropeptides were evaluated by immunohistochemistry using highly specific antisera and stereological analysis. Functional context was assessed relative to c-FOS induction in light-stimulated animals and on neuronal circadian rhythms in glutamate-stimulated brain slices. We found that little SAAS-expressing neurons comprise the third most abundant neuropeptidergic class (16.4%) with unusual functional circuit contexts. Little SAAS is localized within the densely retinorecipient central SCN of both rat and mouse, but not the retinohypothalamic tract (RHT). Some little SAAS colocalizes with vasoactive intestinal polypeptide (VIP) or gastrin-releasing peptide (GRP), known mediators of light signals, but not arginine vasopressin (AVP). Nearly 50% of little SAAS neurons express c-FOS in response to light exposure in early night. Blockade of signals that relay light information, via NMDA receptors or VIP- and GRP-cognate receptors, has no effect on phase delays of circadian rhythms induced by little SAAS. Conclusions/Significance Little SAAS relays signals downstream of light/glutamatergic signaling from eye to SCN, and independent of VIP and GRP action. These findings suggest that little SAAS forms a third SCN neuropeptidergic system, processing light information and activating phase-shifts within novel circuits of the central circadian clock.
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Affiliation(s)
- Norman Atkins
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
| | - Jennifer W. Mitchell
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois, United States of America
| | - Elena V. Romanova
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
| | - Daniel J. Morgan
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Tara P. Cominski
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Jennifer L. Ecker
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - John E. Pintar
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Jonathan V. Sweedler
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Martha U. Gillette
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2008; 15:383-93. [PMID: 18594281 DOI: 10.1097/med.0b013e32830c6b8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Combet S, Gouraud S, Gobin R, Berthonaud V, Geelen G, Corman B, Verbavatz JM. Aquaporin-2 downregulation in kidney medulla of aging rats is posttranscriptional and is abolished by water deprivation. Am J Physiol Renal Physiol 2008; 294:F1408-14. [PMID: 18367658 DOI: 10.1152/ajprenal.00437.2007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aging kidney is associated in humans and rodents with polyuria and reduced urine concentrating ability. In senescent female WAG/Rij rats, this defect is independent of arginine-vasopressin (AVP)/V(2) receptor/cAMP pathway. It has been attributed to underexpression and mistargeting of aquaporin-2 (AQP2) water channel in the inner medullary collecting duct (IMCD). We showed previously that dDAVP administration could partially correct this defect. Since AQP2 can also be regulated by AVP-independent pathways in water deprivation (WD), we investigated AQP2 and phosphorylated AQP2 (p-AQP2) regulation in thirsted adult (10 mo old) and senescent (30 mo old) female WAG/Rij rats. Following 2-day WD, urine flow rate decreased and urine osmolality increased in both groups. However, in agreement with significantly lower cortico-papillary osmotic gradient with aging, urine osmolality remained lower in senescent animals. WD induced sixfold increase of plasma AVP in all animals which, interestingly, did not result in higher papillary cAMP level. Following WD, AQP2 and p-AQP2 expression increased hugely in 10- and 30-mo-old rats and their mistargeting in old animals was corrected. Moreover, the age-related difference in AQP2 regulation was abolished after WD. To further investigate the mechanism of AQP2 underexpression with aging, AQP2 mRNA was quantified by real-time RT-PCR. In the outer medulla, preservation of AQP2 protein expression was achieved through increased AQP2 mRNA level in senescent rats. In the IMCD, no change in AQP2 mRNA was detected with aging but AQP2 protein expression was markedly lower in 30-mo-old animals. In conclusion, there is a posttranscriptional downregulation of AQP2 with aging, which is abolished by WD.
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Affiliation(s)
- S Combet
- CEA, Institut de Biologie et Technologies de Saclay and CNRS URA 2096, Orsay, France.
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Yoshida M. Gene regulation system of vasopressin and corticotropin-releasing hormone. GENE REGULATION AND SYSTEMS BIOLOGY 2008; 2:71-88. [PMID: 19787076 PMCID: PMC2733102 DOI: 10.4137/grsb.s424] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The neurohypophyseal hormones, arginine vasopressin and corticotropin-releasing hormone (CRH), play a crucial role in the physiological and behavioral response to various kinds of stresses. Both neuropeptides activate the hypophysial-pituitary-adrenal (HPA) axis, which is a central mediator of the stress response in the body. Conversely, they receive the negative regulation by glucocorticoid, which is an end product of the HPA axis. Vasopressin and CRH are closely linked to immune response; they also interact with pro-inflammatory cytokines. Moreover, as for vasopressin, it has another important role, which is the regulation of water balance through its potent antidiuretic effect. Hence, it is conceivable that vasopressin and CRH mediate the homeostatic responses for survival and protect organisms from the external world. A tight and elaborate regulation system of the vasopressin and CRH gene is required for the rapid and flexible response to the alteration of the surrounding environments. Several important regulatory elements have been identified in the proximal promoter region in the vasopressin and CRH gene. Many transcription factors and intracellular signaling cascades are involved in the complicated gene regulation system. This review focuses on the current status of the basic research of vasopressin and CRH. In addition to the numerous known facts about their divergent physiological roles, the recent topics of promoter analyses will be discussed.
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Affiliation(s)
- Masanori Yoshida
- Department of Endocrinology, Nagoya Ekisaikai Hospital, 454-8502, Japan.
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Somponpun SJ. Neuroendocrine regulation of fluid and electrolyte balance by ovarian steroids: contributions from central oestrogen receptors. J Neuroendocrinol 2007; 19:809-18. [PMID: 17850463 DOI: 10.1111/j.1365-2826.2007.01587.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Like other hormonally mediated mechanisms, maintenance of body fluid osmolality requires integrated responses from multiple signals at various tissue locales, a large number of which are open to modulation by circulating endocrine factors including the ovarian steroid, oestrogens (E(2)). However, the precise mechanism and the site of action of E(2) in regulating fluid osmolality are not properly understood. More importantly, the biological significance of this action is not clear and the physiological circumstances in which this modulation is engaged remain incomplete. The demonstration of oestrogen receptors (ER) in neural tissues that bear no direct relation to reproduction led us to examine and characterise the expression of ER in brain nuclei that are critical for the maintenance of fluid osmolality. In the rat, ERbeta is prominently expressed in the vasopressin magnocellular neuroendocrine cells of the hypothalamus, whereas ERalpha is localised extensively in the sensory circumventricular organ neurones in the basal forebrain. These nuclei are the primary brain sites that are engaged in defense of fluid perturbation, thus providing a neuroendocrine basis for oestrogenic influence on body fluid regulation. Plasticity in receptor expression that accompanies fluid disturbances at these central loci suggests the functional importance of the receptors and implicates E(2) as one of the fluid regulating hormones in water homeostasis.
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Affiliation(s)
- S J Somponpun
- Department of Clinical Investigation, Tripler Army Medical Center, Tripler AMC, HI 96859, USA.
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15
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Leng G. Proteomics: inspiring new hypotheses in the vasopressin system. Endocrinology 2007; 148:3039-40. [PMID: 17575058 DOI: 10.1210/en.2007-0489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Gareth Leng
- Centre for Integrative Physiology, University of Edinburgh College of Medicine, Edinburgh EH8 9XD, United Kingdom.
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