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Kotwicka M, Skibinska I, Jendraszak M, Jedrzejczak P. 17β-estradiol modifies human spermatozoa mitochondrial function in vitro. Reprod Biol Endocrinol 2016; 14:50. [PMID: 27565707 PMCID: PMC5002130 DOI: 10.1186/s12958-016-0186-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 08/19/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It is assumed that spermatozoa are target cells for estrogens however, the mechanism of their action is not fully understood. The aim of this study was to investigate the influence of 17β-estradiol (E2) on the human spermatozoa mitochondrial function. METHODS The effects on spermatozoa of E2 at final concentrations of 10(-10), 10(-8) and 10(-6) M were studied regarding the following phenomena: (1) kinetics of intracellular free calcium ions changes (using Fluo-3), (2) mitochondrial membrane potential ΔΨm (using JC-1 fluorochrome), (3) production of superoxide anion in mitochondria (using MitoSOX RED dye), (4) spermatozoa vitality (propidium iodide staining) and (5) phosphatidylserine membrane translocation (staining with annexin V marked with fluorescein). RESULTS E2 initiated rapid (within a few seconds) dose dependent increase of intracellular free calcium ions concentration. E2 was changing the mitochondrial membrane potential: 10(-8) M initiated significant increase of percentage of high ΔΨm spermatozoa while the 10(-6) M induced significant decrease of high ΔΨm cells. In spermatozoa stimulated with E2 10(-6) M a significant increase of mitochondrial superoxide anion level was observed. 2 h incubation of spermatozoa with E2 did not alter cells vitality nor stimulated phosphatidylserine membrane translocation, for all three doses. CONCLUSIONS 17β-estradiol affected the human spermatozoa mitochondrial function. E2 in low concentration improved while in high concentration might deteriorate mitochondrial function.
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Affiliation(s)
- Malgorzata Kotwicka
- Department of Cell Biology, Faculty of Health Sciences, Poznan University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan, Poland
| | - Izabela Skibinska
- Department of Cell Biology, Faculty of Health Sciences, Poznan University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan, Poland
| | - Magdalena Jendraszak
- Department of Cell Biology, Faculty of Health Sciences, Poznan University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan, Poland
| | - Piotr Jedrzejczak
- Division of Infertility and Reproductive Endocrinology, Faculty of Medicine I, Poznan University of Medical Sciences, Polna 33, 60-535 Poznan, Poland
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Streck EL, Gonçalves CL, Furlanetto CB, Scaini G, Dal-Pizzol F, Quevedo J. Mitochondria and the central nervous system: searching for a pathophysiological basis of psychiatric disorders. REVISTA BRASILEIRA DE PSIQUIATRIA 2014; 36:156-67. [DOI: 10.1590/1516-4446-2013-1224] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/03/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Emilio L. Streck
- Universidade do Extremo Sul Catarinense (UNESC), Brazil; National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil
| | - Cinara L. Gonçalves
- Universidade do Extremo Sul Catarinense (UNESC), Brazil; National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil
| | - Camila B. Furlanetto
- Universidade do Extremo Sul Catarinense (UNESC), Brazil; National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil
| | - Giselli Scaini
- Universidade do Extremo Sul Catarinense (UNESC), Brazil; National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil
| | - Felipe Dal-Pizzol
- Universidade do Extremo Sul Catarinense (UNESC), Brazil; National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil
| | - João Quevedo
- National Science and Technology Institute for Translational Medicine (INCT-TM), Brazil; Center of Excellence in Applied Neurosciences of Santa Catarina (NENASC), Brazil; UNESC, Brazil
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17β-estradiol modulates mitochondrial Ca²⁺ flux in rat caudate nucleus and brain stem. Neuroscience 2012; 220:32-40. [PMID: 22735576 DOI: 10.1016/j.neuroscience.2012.06.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/15/2012] [Accepted: 06/15/2012] [Indexed: 11/21/2022]
Abstract
The aim of this study was to examine the rapid non-genomic effect of 17β-estradiol (E2) on Ca(2+) transport in mitochondria isolated from the nerve terminals (synaptosomes) of caudate nuclei (NC) and brain stems (BS) of ovariectomised female rats. In physiological conditions no effect of E2 on Ca(2+) influx into synaptosomal mitochondria through ruthenium red (RR)-sensitive uniporter was observed. However, in the presence of uncoupling agent carbonyl cyanide4-(trifluoromethoxy)phenylhydrazone (FCCP) (1μmol/l), pre-treatment with 0.5nmol/l E2 protected mitochondrial membrane potential and consequently increased Ca(2+) influx (2.3-fold in NC and 3.1-fold in BS). At the same time, 0.5nmol/l E2 by increasing the affinity of mitochondrial Na(+)/Ca(2+) exchanger for Na(+) inhibited mitochondrial Ca(2+) efflux in NC and BS by about 40%. Also, the specific binding of physiological E2 concentrations (0.1-10nmol/l) to isolated synaptosomal mitochondria was detected. Using membrane impermeable E2 bound to bovine serum albumin and selective inhibitor of mitochondrial Na(+)/Ca(2+) exchanger, we obtained that E2's action on mitochondrial Ca(2+) efflux at least partially is due to the direct effects on the mitochondrial membrane and/or Na(+)/Ca(2+) exchanger located in inner mitochondrial membrane. Our results implicate E2 as a modulator of Ca(2+) concentration in mitochondrial matrix, and ultimately in the cytosol. Given the vital role of Ca(2+) in regulation of total nerve cells activity, especially energy metabolism, neurotransmission and directing the cells toward survival or cell death, the effects on mitochondrial Ca(2+) transport could be one of the important modes of E2 neuromodulatory action independent of the genome.
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Simpkins JW, Perez E, Wang X, Yang S, Wen Y, Singh M. The potential for estrogens in preventing Alzheimer's disease and vascular dementia. Ther Adv Neurol Disord 2011; 2:31-49. [PMID: 19890493 DOI: 10.1177/1756285608100427] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Estrogens are the best-studied class of drugs for potential use in the prevention of Alzheimer's disease (AD). These steroids have been shown to be potent neuroprotectants both in vitro and in vivo, and to exert effects that are consistent with their potential use in prevention of AD. These include the prevention of the processing of amyloid precursor protein (APP) into beta-amyloid (Aß), the reduction in tau hyperphosphorylation, and the elimination of catastrophic attempts at neuronal mitosis. Further, epidemiological data support the efficacy of early postmenopausal use of estrogens for the delay or prevention of AD. Collectively, this evidence supports the further development of estrogen-like compounds for prevention of AD. Several approaches to enhance brain specificity of estrogen action are now underway in an attempt to reduce the side effects of chronic estrogen therapy in AD.
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Affiliation(s)
- James W Simpkins
- Department of Pharmacology and Neuroscience, Institute for Aging and Alzheimer's Disease Research, Center FOR HER (Focused On Resources for her Health, Education and Research), University of North Texas Health Science Center, Fort Worth, TX, USA
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Petrović S, Veličković N, Stanojević I, Milošević M, Drakulić D, Stanojlović M, Horvat A. Inhibition of mitochondrial Na+-dependent Ca²+ efflux by 17β-estradiol in the rat hippocampus. Neuroscience 2011; 192:195-204. [PMID: 21726603 DOI: 10.1016/j.neuroscience.2011.06.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 05/20/2011] [Accepted: 06/09/2011] [Indexed: 01/18/2023]
Abstract
Our results, as well as those of others, have indicated that 17β-estradiol (E2) exerts its nongenomic effects in neuronal cells by affecting plasma membrane Ca(2+) flux. In neuronal cells mitochondria possess Ca(2+) buffering properties as they both sequester and release Ca(2+). The goal of this study was to examine the rapid non-genomic effect of E2 on mitochondrial Ca(2+) transport in hippocampal synaptosomes from ovariectomised rats. In addition, we aimed to determine if, and to what extent, E2 receptors participated in mitochondrial Ca(2+) transport modulation by E2 in vitro. E2-specific binding and Ca(2+) transport was monitored. At physiological E2 concentrations (0.1-1.5 nmol/L), specific E2 binding to mitochondria isolated from hippocampal synaptosomes was detected with a B(max.) and K(m) of 37.6±2.6 fmol/mg protein and 0.69±0.14 nmol/L of free E2, respectively. The main mitochondrial Ca(2+) influx mechanism is the Ruthenium Red-sensitive uniporter driven by mitochondrial membrane potential. Despite no effect of E2 on Ca(2+) influx, a physiological E2 concentration (0.5 nmol/L) protected mitochondrial membrane potential and consequently Ca(2+) influx from the uncoupling agent carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (1 μmol/L). In neuronal cells the predominant mitochondrial Ca(2+) efflux mechanism is the Na(+)/Ca(2+) exchanger. E2 caused Ca(2+) efflux inhibition (by 46%) coupled with increased affinity of the Na(+)/Ca(2+) exchanger for Na(+). Using E2 receptor (ERα and ERβ) antagonists and agonists, we confirmed ERβ's involvement in E2-induced mitochondrial membrane potential protection as well as Ca(2+) efflux inhibition. In summary, our results indicate that the non-genomic neuromodulatory role of E2 in rat hippocampus is achieved by affecting mitochondrial Ca(2+) transport via, in part, mitochondrial ERβ.
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Affiliation(s)
- S Petrović
- Laboratory for Molecular Biology and Endocrinology, Institute of Nuclear Sciences "Vinča", University of Belgrade, PO Box 522, 11001 Belgrade, Serbia
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Effect of acute stress on NTPDase and 5'-nucleotidase activities in brain synaptosomes in different stages of development. Int J Dev Neurosci 2009; 28:175-82. [PMID: 19932163 DOI: 10.1016/j.ijdevneu.2009.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 11/05/2009] [Accepted: 11/15/2009] [Indexed: 12/20/2022] Open
Abstract
The aim of the present study was to examine the effect of acute restraint stress on rat brain synaptosomal plasma membrane (SPM) ecto-nucleotidase activities at specific stages of postnatal development (15-, 30-, 60- and 90-day-old rats) by measuring the rates of ATP, ADP and AMP hydrolysis 1, 24 and 72 h post-stress. At 1 h after stress NTPDase and ecto-5'-nucleotidase activities were decreased in rats aged up to 60 days old. In adult rats elevated enzyme activities were detected, which indicated the existence of different short-term stress responses during development. A similar pattern of ATP and ADP hydrolysis changes as well as the ATP/ADP ratio in all developmental stages indicated that NTPDase3 was acutely affected after stress. The long-term effect of acute stress on NTPDase activity differed during postnatal development. In juvenile animals (15 days old) NTPDase activity was not altered. However, in later developmental stages (30 and 60 days old rats) NTPDase activity decreased and persisted for 72 h post-stress. In adult rats only ATP hydrolysis was decreased after 24 h, indicating that ecto-ATPase was affected by stress. Ecto-5'-nucleotidase hydrolysing activity was decreased within 24 h in adult rats, while in 15- and 30-day old rats it decreased 72 h post-stress. At equivalent times in pubertal rats (60 days old) a slight activation of ecto-5'-nucleotidase was detected. Our results highlight the developmental-dependence of brain ecto-nucleotidase susceptibility to acute stress and the likely existence of different mechanisms involved in time-dependent ecto-nucleotidase activity modulation following stress exposure. Clearly there are differences in the response of the purinergic system to acute restraint stress between young and adult rats.
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Stanojević I, Drakulić D, Veličković N, Milošević M, Petrović S, Horvat A. Effects of acute gamma-irradiation on extracellular adenine nucleotide hydrolysis in developing rat brain. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2009. [DOI: 10.1134/s0036024409090325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Milanesi L, Vasconsuelo A, de Boland AR, Boland R. Expression and subcellular distribution of native estrogen receptor beta in murine C2C12 cells and skeletal muscle tissue. Steroids 2009; 74:489-97. [PMID: 19428437 DOI: 10.1016/j.steroids.2009.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 12/31/2008] [Accepted: 01/16/2009] [Indexed: 12/11/2022]
Abstract
We have recently described the expression and intracellular localization of ER alpha in murine C2C12 cells and skeletal muscle tissue. In separate studies, a protective role of 17beta-estradiol against apoptosis exerted mainly at the mitochondrial level was also shown in the C2C12 muscle cell line. However, this functional evidence was in accordance with the participation of ER beta. We have then here investigated the expression and subcellular distribution of native ER beta in similar skeletal muscle cultured cells and tissue developed in vivo. ER beta was detected by immunoblotting using specific antibodies and ligand blot analysis after subcellular fractionation. Immunolocalization was confirmed using conventional and confocal microscopy. ER beta was found to a great extent in mitochondria and in lower amounts in the cytosolic fraction, differently to ER alpha which localizes in microsomes, cytosol, mitochondria, and also in the nucleus of muscle tissue. ER beta expression was also demonstrated by RT-PCR. Finally, the mitochondrial localization of native ER beta in C2C12 muscle cells was corroborated after transient transfection with specific ER beta siRNAs. These data raise the possibility that the antiapoptotic action of 17beta-estradiol in muscle cells may be related in part to a direct action of the hormone on mitochondria through ER beta.
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Affiliation(s)
- Lorena Milanesi
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
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Inhibition of mitochondrial Na-dependent Ca2+ efflux from rat brain stem by 17β-estradiol. ARCH BIOL SCI 2009. [DOI: 10.2298/abs0902171p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The role of membrane-bound estradiol in modulation of mitochondrial Ca2+ flux in nerve endings isolated from rat brain stem was examined. Physiological concentrations of 17?-estradiol bind specifically to isolated mitochondria (Bmax 33.8 ? 2.5 fmoles estradiol/mg of protein, Km 0.185 ? 0.006 nmoles/l free estradiol). At concentrations ranging from 1 x 10-10 to 2 x 10-9 moles/l, estradiol significantly (by 23-28%) decreases mitochondrial Na-dependent calcium efflux. Decreased calcium efflux was associated with increased affinity of the Na+/Ca2+ exchanger for Na+ and decreased capacity of the exchanger to extrude Ca2+. Calcium ion efflux modulation and mitochondrial ion retention may be the way that 17?-estradiol exerts its role in nerve cell homeostasis.
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Milanesi L, de Boland AR, Boland R. Expression and localization of estrogen receptor α in the C2C12 murine skeletal muscle cell line. J Cell Biochem 2008; 104:1254-73. [DOI: 10.1002/jcb.21706] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Pradhan DS, Yu Y, Soma KK. Rapid estrogen regulation of DHEA metabolism in the male and female songbird brain. J Neurochem 2007; 104:244-53. [PMID: 17949414 DOI: 10.1111/j.1471-4159.2007.04953.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the songbird brain, dehydroepiandrosterone (DHEA) is metabolized to the active and aromatizable androgen androstenedione (AE) by 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase (3beta-HSD). Thus, brain 3beta-HSD plays a key role in regulating the steroidal milieu of the nervous system. Previous studies have shown that stress rapidly regulates brain 3beta-HSD activity in a sex-specific manner. To elucidate endocrine regulation of brain 3beta-HSD, we asked whether 17beta-estradiol (E(2)) regulates DHEA metabolism in adult zebra finch (Taeniopygia guttata) and whether there are sex-specific effects. Brain tissue was homogenized and centrifuged to obtain supernatant lacking whole cells and cell nuclei. Supernatant was incubated with [(3)H]DHEA and radioinert E(2)in vitro. Within only 10 min, E(2) significantly reduced 3beta-HSD activity in both male and female brain. Interestingly, the rapid effects of E(2) were more pronounced in females than males. These are the first data to show a rapid effect of estrogens on the songbird brain and suggest that rapid estrogen effects differ between male and female brains.
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Affiliation(s)
- Devaleena S Pradhan
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
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Petrović S, Demajo M, Horvat A. Estradiol Affects Calcium Transport across Mitochondrial Membrane in Different Brain Regions. Ann N Y Acad Sci 2006; 1048:341-3. [PMID: 16154947 DOI: 10.1196/annals.1342.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The in vitro effect of estradiol on flux of Ca(2+) in the synaptosomal mitochondria from nucleus caudatus and hippocampus of chronically ovariectomized female rats was examined. No effect of estradiol on Ca(2+) influx through ruthenium red-sensitive channels was found. Estradiol, at a concentration of 0.05-5 nmol/L for nucleus caudatus and 0.5-5 nmol/L for the hippocampus, decreased Na-dependent Ca(2+) efflux about 25%.
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Affiliation(s)
- Snjezana Petrović
- Institute of Nuclear Sciences Vinca, Laboratory for Molecular Biology and Endocrinology, Belgrade, Serbia and Montenegro.
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Glutamate-induced apoptosis in primary cortical neurons is inhibited by equine estrogens via down-regulation of caspase-3 and prevention of mitochondrial cytochrome c release. BMC Neurosci 2005; 6:13. [PMID: 15730564 PMCID: PMC555946 DOI: 10.1186/1471-2202-6-13] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Accepted: 02/24/2005] [Indexed: 11/30/2022] Open
Abstract
Background Apoptosis plays a key role in cell death observed in neurodegenerative diseases marked by a progressive loss of neurons as seen in Alzheimer's disease. Although the exact cause of apoptosis is not known, a number of factors such as free radicals, insufficient levels of nerve growth factors and excessive levels of glutamate have been implicated. We and others, have previously reported that in a stable HT22 neuronal cell line, glutamate induces apoptosis as indicated by DNA fragmentation and up- and down-regulation of Bax (pro-apoptotic), and Bcl-2 (anti-apoptotic) genes respectively. Furthermore, these changes were reversed/inhibited by estrogens. Several lines of evidence also indicate that a family of cysteine proteases (caspases) appear to play a critical role in neuronal apoptosis. The purpose of the present study is to determine in primary cultures of cortical cells, if glutamate-induced neuronal apoptosis and its inhibition by estrogens involve changes in caspase-3 protease and whether this process is mediated by Fas receptor and/or mitochondrial signal transduction pathways involving release of cytochrome c. Results In primary cultures of rat cortical cells, glutamate induced apoptosis that was associated with enhanced DNA fragmentation, morphological changes, and up-regulation of pro-caspase-3. Exposure of cortical cells to glutamate resulted in a time-dependent cell death and an increase in caspase-3 protein levels. Although the increase in caspase-3 levels was evident after 3 h, cell death was only significantly increased after 6 h. Treatment of cells for 6 h with 1 to 20 mM glutamate resulted in a 35 to 45% cell death that was associated with a 45 to 65% increase in the expression of caspase-3 protein. Pretreatment with caspase-3-protease inhibitor z-DEVD or pan-caspase inhibitor z-VAD significantly decreased glutamate-induced cell death of cortical cells. Exposure of cells to glutamate for 6 h in the presence or absence of 17β-estradiol or Δ8, 17β-estradiol (10 nM-10 μM) resulted in the prevention of cell death and was associated with a significant dose-dependent decrease in caspase-3 protein levels, with Δ8, 17β-E2 being more potent than 17β-E2. Protein levels of Fas receptor remained unchanged in the presence of glutamate. In contrast, treatment with glutamate induced, in a time-dependent manner, the release of cytochrome c into the cytosol. Cytosolic cytochrome c increased as early as 1.5 h after glutamate treatment and these levels were 5 fold higher after 6 h, compared to levels in the untreated cells. Concomitant with these changes, the levels of cytochrome c in mitochondria decreased significantly. Both 17β-E2 and Δ8, 17β-E2 reduced the release of cytochrome c from mitochondria into the cytosol and this decrease in cytosolic cytochrome c was associated with inhibition of glutamate-induced cell death. Conclusion In the primary cortical cells, glutamate-induced apoptosis is accompanied by up-regulation of caspase-3 and its activity is blocked by caspase protease inhibitors. These effects of glutamate on caspase-3 appear to be independent of changes in Fas receptor, but are associated with the rapid release of mitochondrial cytochrome c, which precedes changes in caspase-3 protein levels leading to apoptotic cell death. This process was differentially inhibited by estrogens with the novel equine estrogen Δ8, 17β-E2 being more potent than 17β-E2. To our knowledge, this is the first study to demonstrate that equine estrogens can prevent glutamate-induced translocation of cytochrome c from mitochondria to cytosol in rat primary cortical cells.
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Perreault ML, Rollo CD. Transgenic growth hormone mice exposed to lifetime constant illumination: gender-specific effects. CAN J ZOOL 2004. [DOI: 10.1139/z04-071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Photoperiod affects most of the features altered in transgenic growth hormone (TG) mice, and laboratory rats and mice retain some sensitivity to photoperiod. We examined growth, feeding, longevity, and reproduction of TG mice and normal control mice (Mus musculus L., 1758) in 12 h light : 12 h dark (LD) and 24 h light (LL) photoperiods. Sexual dichotomy in growth and hepatic gene expression are considered to require gender-specific patterns of growth hormone secretion that are absent in TG mice. Regardless, in the LD photoperiod mature TG females were 82.8% (46.8 g) of the mass of TG males (56.5 g, p < 0.05), whereas control mice showed no size dichotomy (≈33 g). Mature masses of TG males and of control mice of either gender were unaffected by the LL photoperiod. TG females, however, reached a mature mass 92% (50.9 g) of that of mature TG males in the LL photoperiod, attenuating the sexual size dichotomy expressed in the LD photoperiod. Growth of females was slower than that of males, even in the control group. TG females in the LL photoperiod expressed faster growth, higher reproduction, and greater mean longevity than TG females in the LD photoperiod. Differences in age-related feeding associated with gender and photoperiod reflected differential growth rates. Females grew more slowly and ate more than males of similar age because they were smaller (i.e., had lower growth efficiencies). The LL photoperiod improved the energy balance of TG females. Possible mechanisms mediating such gender-specific effects are explored.
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Kajta M, Beyer C. Cellular strategies of estrogen-mediated neuroprotection during brain development. Endocrine 2003; 21:3-9. [PMID: 12777697 DOI: 10.1385/endo:21:1:3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2003] [Revised: 01/27/2003] [Accepted: 02/06/2003] [Indexed: 11/11/2022]
Abstract
The role of estrogen during brain development is well documented. Estrogen influences cell survival and differentiation and also controls the formation and maintenance of neural networks. Knowledge of trophic estrogen action in the central nervous system (CNS) was the basis for the establishment of research programs directed toward a potential function of estrogen as a neuroprotective factor in the adult brain. Considerable evidence has accumulated over the years supporting this hypothesis. Experimental and epidemiologic studies as well as clinical trials have demonstrated that estrogen is beneficial for the course of neurodegenerative disorders such as Parkinson and Alzheimer diseases but may also protect neurons from postischemic neuronal degeneration. In this article, we aim to unravel potential physiologic responses and cell survival strategies that allow a more detailed understanding of estrogen-mediated neuroprotection in the brain. In particular, we focus on the participation of estrogen in the regulation of apoptotic processes. Furthermore, we present data on reciprocal estrogen-growth factor interactions. Both of these mechanisms were found to operate during brain development and to conciliate estrogen effects on neurons. This makes them likely candidates for taking part in conveying estrogen-dependent neuroprotection in the adult CNS.
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Affiliation(s)
- Malgorzata Kajta
- Department of Endocrinology, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
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Azcoitia I, DonCarlos LL, Garcia-Segura LM. Are gonadal steroid hormones involved in disorders of brain aging? Aging Cell 2003; 2:31-7. [PMID: 12882332 DOI: 10.1046/j.1474-9728.2003.00013.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human aging is associated with a decrease of circulating gonadal steroid hormones. Since these hormones act as trophic factors for neurones and glia, it is possible that the decrease in sex steroid levels may contribute to the increased risk of neurodegenerative disorders with advanced age. Sex steroids are neuroprotective in several animal models of central and peripheral neurodegenerative diseases, and clinical data suggest that these hormones may reduce the risk of neural pathology in aged humans. Potential therapeutic approaches for aged-associated neural disorders may emerge from studies conducted to understand the mechanisms of action of sex steroids in the nervous system of aged animals. Alterations in the endogenous capacity of the aged brain to synthesize and metabolize sex steroids, as well as possible aged-associated modifications in the signalling of sex steroid receptors in the nervous system, are important areas for future investigation.
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Affiliation(s)
- Iñigo Azcoitia
- Departamento de Biología Celular, Facultad de Biología, Universidad Complutense, E-28040 Madrid, Spain
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Morin C, Zini R, Simon N, Tillement JP. Dehydroepiandrosterone and alpha-estradiol limit the functional alterations of rat brain mitochondria submitted to different experimental stresses. Neuroscience 2003; 115:415-24. [PMID: 12421607 DOI: 10.1016/s0306-4522(02)00416-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The effects of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), alpha-estradiol and beta-estradiol on the main functions of purified rat brain mitochondria were investigated in basal conditions and after being submitted to various stresses including anoxia-reoxygenation, uncoupling and apoptosis. In basal conditions, DHEA (1 microM) and alpha-estradiol (1 microM) inhibited the respiratory control ratio (RCR) from 3.1 to 2.3 (25%). After anoxia-reoxygenation, DHEA (1 microM) and alpha-estradiol (1 microM) reversed significantly (P<0.01) the RCR decrease from 1.4 to 2.0 (21.5%) by restoring the state 4. This effect was observed when DHEA was added either before anoxia or before reoxygenation and when alpha-estradiol was added before anoxia. The mitochondrial membranes damaged after the anoxia-reoxygenation were 70 and 50%, respectively, protected by DHEA and alpha-estradiol at 1 microM. They also limited by about 50%, the cytochrome c release induced by the anoxia-reoxygenation. The oxygen consumption of mitochondria in presence of NADH (130 microM) and cytochrome c (5 microM) was significantly inhibited by DHEA and alpha-estradiol with high EC(50) of 30 and 22 pM, respectively. At 1 microM, they also inhibited the 10 microM carbonyl cyanide m-chlorophenylhydrazone-induced uncoupling to about 35% whereas beta-estradiol only decreased it to 9%. Our results indicated that DHEA and alpha-estradiol partly preserved the mitochondrial functions altered by an anoxia-reoxygenation with a concentration-dependent effect. The mechanism involved was independent of the classical genomic effect of steroids, the antioxidant properties but implicated a direct action on the mitochondrial membranes.
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Affiliation(s)
- C Morin
- Département de Pharmacologie, Faculté de Médecine de Paris XII, 8 rue du Général Sarrail, F-94010 Créteil, France.
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