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Abdelmissih S, Sayed WM, Rashed LA, Kamel MM, Eshra MA, Attallah MI, El-Naggar RAR. The extent of involvement of ouabain, hippocampal expression of Na+/K+-ATPase, and corticosterone/melatonin receptors ratio in modifying stress-induced behavior differs according to the stressor in context. Braz J Med Biol Res 2022; 55:e11938. [PMID: 35857994 PMCID: PMC9296128 DOI: 10.1590/1414-431x2022e11938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 04/18/2022] [Indexed: 11/21/2022] Open
Abstract
The aim of this study was to assess the effect of two types of stressors,
regarding the extent of involvement of ouabain (OUA), hippocampal
sodium/potassium ATPase (NKA) expression, and the hippocampal
corticosterone receptors (CR)/melatonin receptors
(MR) expression ratio, on the behavioral and cardiovascular
responses and on the hippocampal cornu ammonis zone 3 (CA3) and dentate gyrus
(DG). Thirty adult male Wistar albino rats aged 7-8 months were exposed to
either chronic immobilization or a disturbed dark/light cycle and treated with
either ouabain or vehicle. In the immobilized group, in the absence of
hippocampal corticosterone (CORT) changes, rats were non-responsive to stress,
despite experiencing increased pulse rate, downregulated hippocampal
sodium/potassium pump, and enhanced hippocampal CR/MR
expression ratio. Prolonged darkness precipitated a reduced upright attack
posture, with elevated CORT against hippocampal MR
downregulation. Both immobilization and, to a lesser extent, prolonged darkness
stress resulted in histopathological and ultrastructural neurodegenerative
changes in the hippocampus. OUA administration did not change the behavioral
resilience in restrained rats, despite persistence of the underlying biochemical
derangements, added to decreased CORT. On the contrary, with exposure to short
photoperiods, OUA reverted the behavior towards a combative reduction of
inactivity, with unvaried CR/MR and CORT, while ameliorating
hippocampal neuro-regeneration, with co-existing NKA and
MR repressions. Therefore, the extent of OUA, hippocampal
NKA expression, and CR/MR expression, and
subsequent behavioral and cardiac responses and hippocampal histopathology,
differ according to the type of stressor, whether immobilization or prolonged
darkness.
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Affiliation(s)
- S Abdelmissih
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - W M Sayed
- Department of Anatomy and Embryology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - L A Rashed
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M M Kamel
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt.,Department of Basic Medical Science, Faculty of Medicine, King Salman International University, South Sinai, Egypt
| | - M A Eshra
- Department of Physiology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M I Attallah
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - R A-R El-Naggar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Misr University for Science and Technology, Giza, Egypt
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Kirshenbaum GS, Idris NF, Dachtler J, Roder JC, Clapcote SJ. Deficits in social behavioral tests in a mouse model of alternating hemiplegia of childhood. J Neurogenet 2017; 30:42-9. [PMID: 27276195 PMCID: PMC4917910 DOI: 10.1080/01677063.2016.1182525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Social behavioral deficits have been observed in patients diagnosed with alternating hemiplegia of childhood (AHC), rapid-onset dystonia-parkinsonism and CAPOS syndrome, in which specific missense mutations in ATP1A3, encoding the Na+, K+-ATPase α3 subunit, have been identified. To test the hypothesis that social behavioral deficits represent part of the phenotype of Na+, K+-ATPase α3 mutations, we assessed the social behavior of the Myshkin mouse model of AHC, which has an I810N mutation identical to that found in an AHC patient with co-morbid autism. Myshkin mice displayed deficits in three tests of social behavior: nest building, pup retrieval and the three-chamber social approach test. Chronic treatment with the mood stabilizer lithium enhanced nest building in wild-type but not Myshkin mice. In light of previous studies revealing a broad profile of neurobehavioral deficits in the Myshkin model – consistent with the complex clinical profile of AHC – our results suggest that Na+, K+-ATPase α3 dysfunction has a deleterious, but nonspecific, effect on social behavior. By better defining the behavioral profile of Myshkin mice, we identify additional ATP1A3-related symptoms for which the Myshkin model could be used as a tool to advance understanding of the underlying neural mechanisms and develop novel therapeutic strategies.
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Affiliation(s)
- Greer S Kirshenbaum
- a Lunenfeld-Tanenbaum Research Institute , Mount Sinai Hospital , University Avenue , Toronto , Canada ;,b Institute of Medical Science, University of Toronto , Toronto , Canada
| | - Nagi F Idris
- c School of Biomedical Sciences , University of Leeds , Leeds , UK
| | - James Dachtler
- c School of Biomedical Sciences , University of Leeds , Leeds , UK
| | - John C Roder
- a Lunenfeld-Tanenbaum Research Institute , Mount Sinai Hospital , University Avenue , Toronto , Canada ;,b Institute of Medical Science, University of Toronto , Toronto , Canada
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Halonen J, Hinton AS, Frisina RD, Ding B, Zhu X, Walton JP. Long-term treatment with aldosterone slows the progression of age-related hearing loss. Hear Res 2016; 336:63-71. [PMID: 27157488 DOI: 10.1016/j.heares.2016.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
Age-related hearing loss (ARHL), clinically referred to as presbycusis, is one of the three most prevalent chronic medical conditions of our elderly, with the majority of persons over the age of 60 suffering from some degree of ARHL. The progressive loss of auditory sensitivity and perceptual capability results in significant declines in workplace productivity, quality of life, cognition and abilities to communicate effectively. Aldosterone is a mineralocorticoid hormone produced in the adrenal glands and plays a role in the maintenance of key ion pumps, including the Na-K(+)-Cl co-transporter 1 or NKCC1, which is involved in homeostatic maintenance of the endocochlear potential. Previously we reported that aldosterone (1 μM) increases NKCC1 protein expression in vitro and that this up-regulation of NKCC1 was not dose-dependent (dosing range from 1 nM to 100 μM). In the current study we measured behavioral and electrophysiological hearing function in middle-aged mice following long-term systemic treatment with aldosterone. We also confirmed that blood pressure remained stable during treatment and that NKCC1 protein expression was upregulated. Pre-pulse inhibition of the acoustic startle response was used as a functional measure of hearing, and the auditory brainstem response was used as an objective measure of peripheral sensitivity. Long-term treatment with aldosterone improved both behavioral and physiological measures of hearing (ABR thresholds). These results are the first to demonstrate a protective effect of aldosterone on age-related hearing loss and pave the way for translational drug development, using aldosterone as a key component to prevent or slow down the progression of ARHL.
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Affiliation(s)
- Joshua Halonen
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Ashley S Hinton
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Robert D Frisina
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Bo Ding
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Xiaoxia Zhu
- Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Joseph P Walton
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA.
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Li Z, Langhans SA. Transcriptional regulators of Na,K-ATPase subunits. Front Cell Dev Biol 2015; 3:66. [PMID: 26579519 PMCID: PMC4620432 DOI: 10.3389/fcell.2015.00066] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/05/2015] [Indexed: 12/20/2022] Open
Abstract
The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease.
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Affiliation(s)
- Zhiqin Li
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
| | - Sigrid A Langhans
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
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Umbach AT, Pathare G, Föller M, Brosens JJ, Artunc F, Lang F. SGK1-dependent salt appetite in pregnant mice. Acta Physiol (Oxf) 2011; 202:39-45. [PMID: 21251236 DOI: 10.1111/j.1748-1716.2011.02251.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Pregnancy is typically paralleled by substantial increase in maternal extracellular fluid volume, requiring net accumulation of water and NaCl. The positive water and salt balance is accomplished at least in part by increased uptake of salt secondary to enhanced salt appetite. Little is known about the underlying cellular mechanisms. Stimulation of salt appetite by mineralocorticoids, however, is known to be dependent on the serum- and glucocorticoid-inducible kinase SGK1. METHODS To test for a role of SGK1 in the stimulation of salt appetite during pregnancy, fluid intake was recorded in pregnant SGK1 knockout mice (sgk1(-/-) ) and their wild type littermates (sgk1(+/+) ). The mice were offered two bottles, one with plain water and the other with isotonic saline. RESULTS In early pregnancy, i.e. up to 10 days prior to parturition, the sgk1(+/+) mice displayed a significant preference for saline, whereas the sgk1(-/-) mice preferred water. Accordingly, the water intake was significantly smaller and saline intake was significantly larger in sgk1(+/+) mice than in sgk1(-/-) mice and the preference for water was significantly stronger in sgk1(-/-) mice than in sgk1(+/+) mice. Plasma aldosterone levels were higher in sgk1(-/-) mice than in sgk1(+/+) mice, a difference contrasting the enhanced salt appetite of sgk1(+/+) mice. CONCLUSIONS SGK1 participates in the stimulation of salt appetite during pregnancy.
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Affiliation(s)
- A T Umbach
- Department of Physiology, University of Tübingen, Germany
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De Nicola AF, Pietranera L, Bellini MJ, Goya R, Brocca ME, Garcia-Segura LM. Protective effect of estrogens on the brain of rats with essential and endocrine hypertension. Horm Mol Biol Clin Investig 2010; 4:549-57. [PMID: 25961231 DOI: 10.1515/hmbci.2010.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 09/02/2010] [Indexed: 11/15/2022]
Abstract
Estrogen neuroprotection has been shown in pathological conditions damaging the hippocampus, such as trauma, aging, neurodegeneration, excitotoxicity, oxidative stress, hypoglycemia, amyloid-β peptide exposure and ischemia. Hypertensive encephalopathy also targets the hippocampus; therefore, hypertension seems an appropriate circumstance to evaluate steroid neuroprotection. Two experimental models of hypertension, spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats, develop hippocampal abnormalities, which include decreased neurogenesis in the dentate gyrus, astrogliosis, low expression of brain-derived neurotrophic factor (BDNF) and decreased number of neurons in the hilar region, with respect of their normotensive strains Wistar Kyoto (WKY) and Sprague-Dawley rats. After estradiol was given for 2 weeks to SHR and DOCA-treated rats, both hypertensive models normalized their faulty hippocampal parameters. Thus, estradiol treatment positively modulated neurogenesis in the dentate gyrus of the hippocampus, according to bromodeoxyuridine incorporation and doublecortin immunocytochemistry, decreased reactive astrogliosis, increased BDNF mRNA and protein expression in the dentate gyrus and increased neuronal number in the hilar region of the dentate gyrus. A role of local estrogen biosynthesis is suggested in SHR, because basal aromatase mRNA in the hippocampus and immunoreactive aromatase protein in cell processes of the dentate gyrus were highly expressed in these rats. Estradiol further stimulated aromatase-related parameters in SHR but not in WKY. These observations strongly support that a combination of exogenous estrogens to those locally synthesized might better alleviate hypertensive encephalopathy. These studies broaden estrogen neuroprotective functions to the hippocampus of hypertensive rat models.
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Vallon V, Huang DY, Grahammer F, Wyatt AW, Osswald H, Wulff P, Kuhl D, Lang F. SGK1 as a determinant of kidney function and salt intake in response to mineralocorticoid excess. Am J Physiol Regul Integr Comp Physiol 2005; 289:R395-R401. [PMID: 16014448 DOI: 10.1152/ajpregu.00731.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mineralocorticoids modify salt balance by both stimulating salt intake and inhibiting salt loss. Renal salt retention is accomplished by upregulation of reabsorption, an effect partially mediated by serum- and glucocorticoid-inducible kinase 1 (SGK1). The present study explored the contribution of SGK1 to the regulation of renal function, salt intake, and blood pressure during mineralocorticoid excess. DOCA/1% NaCl treatment increased blood pressure and creatinine clearance to a similar extent in SGK1-deficient sgk1−/−and wild-type sgk1+/+mice but led to more pronounced increase of proteinuria in sgk1+/+mice (by 474 ± 89%) than in sgk1−/−mice (by 154 ± 31%). DOCA/1% NaCl treatment led to significant increase of kidney weight (by 24%) and to hypokalemia (from 3.9 ± 0.1 to 2.7 ± 0.1 mmol/l) only in sgk1+/+mice. The treatment enhanced renal Na+excretion significantly more in sgk1+/+mice (from 3 ± 1 to 134 ± 32 μmol·24 h−1·g body wt−1) than in sgk1−/−mice (from 4 ± 1 to 49 ± 8 μmol·24 h−1·g body wt−1), pointing to SGK1-dependent stimulation of salt intake. With access to two drinking bottles containing 1% NaCl or water, DOCA treatment did not significantly affect water intake in either genotype but increased 1% NaCl intake in sgk1+/+mice (within 9 days from 3.5 ± 0.9 to 16.5 ± 2.4 ml/day) consistent with DOCA-induced salt appetite. This response was significantly attenuated in sgk1−/−mice (from 2.6 ± 0.6 to 5.9 ± 0.9 ml/day). Thus SGK1 contributes to the stimulation of salt intake, kidney growth, proteinuria, and renal K+excretion during mineralocorticoid excess.
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Affiliation(s)
- Volker Vallon
- Dept. of Physiology, University of Tübingen, Gmelinstrasse 5, D-72076 Tübingen, Germany
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Tadros SF, Frisina ST, Mapes F, Frisina DR, Frisina RD. Higher serum aldosterone correlates with lower hearing thresholds: a possible protective hormone against presbycusis. Hear Res 2005; 209:10-8. [PMID: 16039078 DOI: 10.1016/j.heares.2005.05.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 05/27/2005] [Indexed: 11/28/2022]
Abstract
Aldosterone hormone is a mineralocorticoid secreted by adrenal gland cortex and controls serum sodium (Na(+)) and potassium (K(+)) levels. Aldosterone has a stimulatory effect on expression of sodium-potassium ATPase (Na, K-ATPase) and sodium-potassium-chloride cotransporter (NKCC) in cell membranes. In the present investigation, the relation between serum aldosterone levels and age-related hearing loss (presbycusis) and the correlation between these levels versus the degree of presbycusis in humans were examined. Serum aldosterone concentrations were compared between normal hearing and presbycusic groups. Pure-tone audiometry, transient evoked otoacoustic emissions (TEOAE), hearing in noise test (HINT) and gap detection were tested for each subject and compared to the serum aldosterone levels. A highly significant difference between groups in serum aldosterone concentrations was found (p = 0.0003, t = 3.95, df = 45). Highly significant correlations between pure-tone thresholds in both right and left ears, and HINT scores versus serum aldosterone levels were also discovered. On the contrary, no significant correlations were seen in the case of TEOAEs and gap detection. We conclude that aldosterone hormone may have a protective effect on hearing in old age. This effect is more peripheral than central, appearing to affect inner hair cells more than outer hair cells.
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Affiliation(s)
- Sherif F Tadros
- International Center for Hearing and Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, NY 14623, USA
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Marissal-Arvy N, Mormède P. Excretion of electrolytes in Brown Norway and Fischer 344 rats: effects of adrenalectomy and of mineralocorticoid and glucocorticoid receptor ligands. Exp Physiol 2004; 89:753-65. [PMID: 15364879 DOI: 10.1113/expphysiol.2004.028621] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Our previous studies showed that adrenalectomy (ADX) has surprisingly no effect on body weight and fluid intake in the Brown Norway rat strain, suggesting that mineralocorticoid receptor (MR)-mediated effects are present even in absence of corticosteroids in this strain. Moreover, glucocorticoid receptor (GR)-mediated mechanisms are more effective in Brown Norway than in Fischer 344 rats. Such functional differences in corticosteroid receptor pathways between Brown Norway and Fischer 344 rats led us to compare the effect of ADX and MR/GR-mediated actions on sodium and potassium excretion between these two rat strains. To this end, we first measured the effect of an acute high dose of aldosterone on the urinary Na+/K+ concentration ratio in intact and ADX Brown Norway and Fischer 344 rats. Second, to discriminate mineralocorticoid from glucocorticoid actions, we treated chronically ADX rats with increasing doses of aldosterone or RU28362, a pure GR agonist, in the drinking fluid. As sodium homeostasis involves salt appetite regulation, behaviour under mineralocorticoid control, we also measured saline preference in Brown Norway and Fischer 344 rats. Our data illustrate: (1) the very limited effect of ADX on body weight, food and fluid intake, diuresis, natriuresis, kaliuresis and salt appetite in Brown Norway rats, supporting the presence of MR signalling pathways in the absence of adrenal steroids in these rats; (2) the insensitivity of MR to aldosterone in intact Brown Norway rats, and the reduced sensitivity of MR to aldosterone in ADX Brown Norway rats compared with ADX Fischer 344 rats; and (3) the greater sensitivity of GR-related mechanisms to RU28362 in Brown Norway than in Fischer 344 rats in terms of body weight gain and electrolyte excretion. Considering that both MRs and GRs regulate hypothalamic-pituitary-adrenal axis processes, such functional differences in corticosteroid receptors could be at the origin, at least partly, of the strain differences in corticotropic activity/reactivity to stress previously described.
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Affiliation(s)
- Nathalie Marissal-Arvy
- Neurogénétique et Stress, INSERM U471 - INRA UMR1243 - Université de Bordeaux 2, Institut François Magendie de Neurosciences, 1, rue Camille Saint Saëns, 33077 Bordeaux Cedex, France.
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10
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Gonzalez Deniselle MC, Lopez Costa JJ, Gonzalez SL, Labombarda F, Garay L, Guennoun R, Schumacher M, De Nicola AF. Basis of progesterone protection in spinal cord neurodegeneration. J Steroid Biochem Mol Biol 2002; 83:199-209. [PMID: 12650717 DOI: 10.1016/s0960-0760(02)00262-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Progesterone neuroprotection has been reported in experimental brain, peripheral nerve and spinal cord injury. To investigate for a similar role in neurodegeneration, we studied progesterone effects in the Wobbler mouse, a mutant presenting severe motoneuron degeneration and astrogliosis of the spinal cord. Implant of a single progesterone pellet (20 mg) during 15 days produced substantial changes in Wobbler mice spinal cord. Morphologically, motoneurons of untreated Wobbler mice showed severe vacuolation of intracellular organelles including mitochondria. In contrast, neuropathology was less pronounced in Wobbler mice receiving progesterone, together with a reduction of vacuolated cells and preservation of mitochondrial ultrastructure. Determination of mRNAs for the alpha 3 and beta 1 subunits of neuronal Na, K-ATPase, showed that mRNA levels in untreated mice were significantly reduced, whereas progesterone therapy re-established the expression of both subunits. Additionally, progesterone treatment of Wobbler mice attenuated the aberrant expression of the growth-associated protein (GAP-43) mRNA which otherwise occurred in motoneurons of untreated animals. The hormone, however, was without effect on astrocytosis of Wobbler mice, determined by glial fibrillary acidic protein (GFAP)-immunostaining. Lastly, progesterone treatment of Wobbler mice enhanced grip strength and prolonged survival at the end of the 15-day observation period. Recovery of morphology and molecular motoneuron parameters of Wobbler mice receiving progesterone, suggest a new and important role for this hormone in the prevention of spinal cord neurodegenerative disorders.
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Affiliation(s)
- Maria Claudia Gonzalez Deniselle
- Laboratory of Neuroendocrine Biochemistry, Department of Human Biochemistry, Faculty of Medicine, Instituto de Biologia y Medicina Experimental, University of Buenos Aires, Obligado 2490, 1428 Buenos Aires, Argentina
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11
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Labombarda F, Gonzalez SL, Gonzalez DMC, Guennoun R, Schumacher M, de Nicola AF. Cellular basis for progesterone neuroprotection in the injured spinal cord. J Neurotrauma 2002; 19:343-55. [PMID: 11939502 DOI: 10.1089/089771502753594918] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Progesterone (PROG) exerts beneficial and neuroprotective effects in the injured central and peripheral nervous system. In the present work, we examine PROG effects on three measures of neuronal function under negative regulation (choline acetyltransferase [ChAT] and Na,K-ATPase) or stimulated (growth-associated protein [GAP-43]) after acute spinal cord transection injury in rats. As expected, spinal cord injury reduced ChAT immunostaining intensity of ventral horn neurons. A 3-day course of intensive PROG treatment of transected rats restored ChAT immunoreactivity, as assessed by frequency histograms that recorded shifts from predominantly light neuronal staining to medium, dark or intense staining typical of control rats. Transection also reduced the expression of the mRNA for the alpha3 catalytic and beta1 regulatory subunits of neuronal Na,K-ATPase, whereas PROG treatment restored both subunit mRNA to normal levels. Additionally, the upregulation observed for GAP-43 mRNA in ventral horn neurons in spinal cord-transected rats, was further enhanced by PROG administration. In no case did PROG modify ChAT immunoreactivity, Na,K-ATPase subunit mRNA or GAP-43 mRNA in control, sham-operated rats. Further, the PROG-mediated effects on these three markers were observed in large, presumably Lamina IX motoneurons, as well as in smaller neurons measuring approximately <500 micro2. Overall, the stimulatory effects of PROG on ChAT appears to replenish acetylcholine, with its stimulatory effects on Na,K-ATPase seems capable of restoring membrane potential, ion transport and nutrient uptake. PROG effects on GAP-43 also appear to accelerate reparative responses to injury. As the cellular basis for PROG neuroprotection becomes better understood it may prove of therapeutic benefit to spinal cord injury patients.
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Affiliation(s)
- Florencia Labombarda
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental, and Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Argentina
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12
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Abstract
Corticosteroid hormones can enter the brain and bind to two intracellular receptor types that regulate transcription of responsive genes: (i) the high affinity mineralocorticoid receptors and (ii) the glucocorticoid receptors with approximately 10-fold lower affinity. Although most cells in the brain predominantly express glucocorticoid receptors, principal cells in limbic structures such as the hippocampus often contain glucocorticoid as well as mineralocorticoid receptors. Recent electrophysiological studies have examined the consequences of transcriptional regulation via the two receptor types for information transfer in the hippocampus. It was found that, under resting conditions, corticosteroids do not markedly alter electrical activity. However, if neurones are shifted towards more depolarized or hyperpolarized potentials due to the action of neurotransmitters, slow and adaptive effects of the corticosteroid hormones become apparent. In general, mineralocorticoid receptor occupation maintains steady electrical activity in hippocampal neurones. Brief activation of glucocorticoid receptors leads to increased influx of calcium, which normally helps to slowly reverse temporarily raised electrical activity. These slow and persistent corticosteroid actions will alter network function within the hippocampus, thus contributing to behavioural adaptation in response to stress. Modulation of hippocampal activity by corticosteroids also affects hippocampal output (e.g. to inhibitory interneurones which control hypothalamic-pituitary-adrenal axis activity). The enhanced calcium influx after glucocorticoid receptor activation can become a risk factor when cells are simultaneously exposed to strong depolarizing inputs, such as those occurring during ischaemia. Similarly, chronically elevated corticosteroid levels (or lack of corticosteroids) could endanger hippocampal cell function. The latter may contribute to the precipitation of clinical symptoms in diseases associated with chronically aberrant corticosteroid levels.
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Affiliation(s)
- M Joëls
- Swammerdam Institute for Life Sciences, Section of Neurobiology, University of Amsterdam, The Netherlands.
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13
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Fogarty DJ, Matute C. Angiotensin receptor-like immunoreactivity in adult brain white matter astrocytes and oligodendrocytes. Glia 2001; 35:131-46. [PMID: 11460269 DOI: 10.1002/glia.1078] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Most of the physiological effects of brain angiotensins are currently believed to be mediated by angiotensin receptors located principally on neurons. However, numerous studies in vitro have demonstrated the presence of functional angiotensin receptors on brain astrocytes, raising the possibility that glial cells may also participate in mediating the effects of the central renin-angiotensin system. Nevertheless, it is uncertain whether these cells in situ express angiotensin receptors, raising questions about the physiological significance of results observed in cell cultures. We have examined the distribution of angiotensin receptor-like immunoreactivity in glial cells in white matter tracts in the adult CNS, using a panel of antisera to the AT1 and AT2 angiotensin receptors. Antiserum preadsorption and/or Western blot demonstrated the specificity of the antisera in brain tissue. In immunohistochemical experiments, the AT1 antisera selectively labeled AT1-expressing neurons in the piriform cortex, whereas the AT2 antiserum stained cells in the trigeminal motor nucleus, these being nuclei known to express AT1 and AT2 receptors, respectively. Using double-label immunohistochemistry, we observed AT1- and AT2-immunoreactive astrocytes and oligodendrocytes in white matter tracts, which include the rat cerebellar white matter, periventricular white matter, and optic nerve, in addition to the bovine corpus callosum and human subcortical white matter. In contrast, astrocytes in the gray matter region of the cerebral cortex were not found to be angiotensin receptor-like immunoreactive. These results demonstrate the presence of AT1 and/or AT2 angiotensin receptor-like immunoreactivity in brain white matter macroglial cells in situ and support the idea that glial cells may play a more important role in the central renin-angiotensin system than previously thought.
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Affiliation(s)
- D J Fogarty
- Department of Neurosciences, Faculty of Medicine, University of the Basque Country, Leioa, Spain
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Abstract
The Na(+)-K(+)-ATPase, or sodium pump, is the membrane-bound enzyme that maintains the Na(+) and K(+) gradients across the plasma membrane of animal cells. Because of its importance in many basic and specialized cellular functions, this enzyme must be able to adapt to changing cellular and physiological stimuli. This review presents an overview of the many mechanisms in place to regulate sodium pump activity in a tissue-specific manner. These mechanisms include regulation by substrates, membrane-associated components such as cytoskeletal elements and the gamma-subunit, and circulating endogenous inhibitors as well as a variety of hormones, including corticosteroids, peptide hormones, and catecholamines. In addition, the review considers the effects of a range of specific intracellular signaling pathways involved in the regulation of pump activity and subcellular distribution, with particular consideration given to the effects of protein kinases and phosphatases.
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Affiliation(s)
- A G Therien
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1A4
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15
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González Deniselle MC, González SL, Lima AE, Wilkin G, De Nicola AF. The 21-aminosteroid U-74389F attenuates hyperexpression of GAP-43 and NADPH-diaphorase in the spinal cord of wobbler mouse, a model for amyotrophic lateral sclerosis. Neurochem Res 1999; 24:1-8. [PMID: 9973230 DOI: 10.1023/a:1020918310281] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The wobbler mouse suffers an autosomal recessive mutation producing severe neurodegeneration and astrogliosis in spinal cord. It has been considered a model for amyotrophic lateral sclerosis. We have studied in these animals the expression of two proteins, the growth-associated protein (GAP-43) and the NADPH-diaphorase, the nitric oxide synthesizing enzyme, employing immunocytochemistry and histochemistry. We found higher expression of GAP-43 immunoreactivity in dorsal horn, Lamina X, corticospinal tract and ventral horn motoneurons in wobbler mice compared to controls. Weak NADPH-diaphorase activity was present in control motoneurons, in contrast to intense labeling of the wobbler group. No differences in diaphorase activity was measured in the rest of the spinal cord between control and mutant mice. A group of animals received subcutaneously for 4 days a 50 mg pellet of U-74389F, a glucocorticoid-derived 21-aminosteroid with antioxidant properties but without glucocorticoid activity. U-74389F slightly attenuated GAP-43 immunostaining in dorsal regions of the spinal cord from wobblers but not in controls. However, in motoneurons of wobbler mice number of GAP-43 immunopositive neurons, cell processes and reaction intensity were reduced by U-74389F. The aminosteroid reduced by 50% motoneuron NADPH-diaphorase activity. Hyperexpression of GAP-43 immunoreactivity in wobbler mice may represent an exaggerated neuronal response to advancing degeneration or muscle denervation. It may also be linked to increased nitric oxide levels. U-74389F may stop neurodegeneration and/or increase muscle trophism and stop oxidative stress, consequently GAP-43 hyperexpression was attenuated. Wobbler mice may be important models to evaluate the use of antioxidant steroid therapy with a view to its use in human motoneuron disease.
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Affiliation(s)
- M C González Deniselle
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental, Buenos Aires, Argentina
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