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Sadek B, Oz M, Nurulain SM, Jayaprakash P, Latacz G, Kieć-Kononowicz K, Szymańska E. Phenylalanine derivatives with modulating effects on human α1-glycine receptors and anticonvulsant activity in strychnine-induced seizure model in male adult rats. Epilepsy Res 2017; 138:124-131. [PMID: 28554717 DOI: 10.1016/j.eplepsyres.2017.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/01/2017] [Accepted: 05/19/2017] [Indexed: 01/27/2023]
Abstract
The critical role of α1-glycine receptor (α1-GLYRs) in pathological conditions such as epilepsy is well known. In the present study, structure-activity relations for a series of phenylalanine derivatives carrying selected hydrogen bond acceptors were investigated on the functional properties of human α1-GLYR expressed in Xenopus oocytes. The results indicate that one particular substitution position appeared to be of special importance for control of ligand activity. Among tested ligands (1-8), the biphenyl derivative (2) provided the most promising antagonistic effect on α1-GLYRs, while its phenylbenzyl analogue (5) exhibited the highest potentiation effect. Moreover, ligand 5 with most promising potentiating effect showed in-vivo moderate protection when tested in strychnine (STR)-induced seizure model in male adult rats, whereas ligand 2 with highest antagonistic effect failed to provide appreciable anti(pro)convulsant effect. Furthermore, ligands 2 and 5 with the most promising effects on human α1-GLYRs were examined for their toxicity and potential neuroprotective effect against neurotoxin 6-hydroxydopamine (6-OHDA). The results show that ligands 2 and 5 possessed neither significant antiproliferative effects, nor necrotic and mitochondrial toxicity (up to concentration of 50μM). Moreover, ligand 2 showed weak neuroprotective effect at the 50μM against 100μM toxic dose of 6-OHDA. Our results indicate that modulatory effects of ligands 2 and 5 on human α1-GLYRs as well as on STR-induced convulsion can provide further insights for the design of therapeutic agents in treatment of epilepsy and other pathological conditions requiring enhanced activity of inhibitory glycine receptors.
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Affiliation(s)
- Bassem Sadek
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, P.O. Box 17666, United Arab Emirates.
| | - Murat Oz
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, P.O. Box 17666, United Arab Emirates; Department of Basic Medical Sciences, College of Medicine, Qatar University, Doha, Qatar
| | - Syed M Nurulain
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, P.O. Box 17666, United Arab Emirates; Department of Bioscience, COMSATS Institute of Information Technology, Islamabad 45550, Pakistan
| | - Petrilla Jayaprakash
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, P.O. Box 17666, United Arab Emirates
| | - Gniewomir Latacz
- Department of Technology and Biotechnology of Drugs Jagiellonian University Medical College, Medyczna 9, PL 30-688 Krakow, Poland
| | - Katarzyna Kieć-Kononowicz
- Department of Technology and Biotechnology of Drugs Jagiellonian University Medical College, Medyczna 9, PL 30-688 Krakow, Poland
| | - Ewa Szymańska
- Department of Technology and Biotechnology of Drugs Jagiellonian University Medical College, Medyczna 9, PL 30-688 Krakow, Poland
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Effect of genistein on the cerebellar cortex of adult male albino rats with streptozotocin-induced diabetes mellitus. ACTA ACUST UNITED AC 2015. [DOI: 10.1097/01.ehx.0000473710.76297.3b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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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: 60] [Impact Index Per Article: 4.6] [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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4
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De Marinis E, Ascenzi P, Pellegrini M, Galluzzo P, Bulzomi P, Arevalo MA, Garcia-Segura LM, Marino M. 17β-Estradiol – A New Modulator of Neuroglobin Levels in Neurons: Role in Neuroprotection against H 2O 2-Induced Toxicity. Neurosignals 2010; 18:223-35. [DOI: 10.1159/000323906] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 12/28/2010] [Indexed: 12/13/2022] Open
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5
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Effects of estrogen on AF64A-induced apoptosis in NG108-15 cells. Brain Res 2009; 1297:9-16. [PMID: 19729002 DOI: 10.1016/j.brainres.2009.08.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/18/2009] [Accepted: 08/24/2009] [Indexed: 11/23/2022]
Abstract
In this study, we show that pretreatment with physiological concentrations (1-100 nM) of 17beta-estradiol decreased apoptosis induced by ethylcholine aziridinium (AF64A), a choline toxin, in the cholinergic neuronal cell line NG108-15. These protective effects were observed after short-term (30 min) pretreatment, and were blocked by treatment with an estrogen receptor antagonist and inhibitors of phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase kinase (MEK). The protective effects were, however, not reversed by a protein synthesis inhibitor. Furthermore, we examined the effects of 17beta-estradiol on choline uptake in NG108-15 cells. Although choline uptake was inhibited by a selective inhibitor of choline uptake, hemicholinium-3, it was not altered by treatment with 17beta-estradiol. These results indicated that the protective effect of 17beta-estradiol on AF64A-induced apoptosis could be nongenomic, and that this effect may be due to the activation of PI3K/Akt and/or MEK/extracellular signal-regulated kinase (ERK) pathways.
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6
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Baluchnejadmojarad T, Roghani M, Nadoushan MRJ, Bagheri M. Neuroprotective effect of genistein in 6-hydroxydopamine Hemi-parkinsonian rat model. Phytother Res 2009; 23:132-5. [DOI: 10.1002/ptr.2564] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Patchev VK, Bachurin SO, Albers M, Fritzemeier KH, Papadopoulos V. Neurotrophic estrogens: essential profile and endpoints for drug discovery☆. Drug Discov Today 2008; 13:734-47. [DOI: 10.1016/j.drudis.2008.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 03/04/2008] [Accepted: 03/12/2008] [Indexed: 11/15/2022]
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8
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Simpkins JW, Dykens JA. Mitochondrial mechanisms of estrogen neuroprotection. ACTA ACUST UNITED AC 2007; 57:421-30. [PMID: 17512984 DOI: 10.1016/j.brainresrev.2007.04.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 04/20/2007] [Accepted: 04/21/2007] [Indexed: 11/19/2022]
Abstract
Oxidative stress, bioenergetic failure and mitochondrial dysfunction are all implicated in the etiology of neurodegenerative diseases such as Alzheimer's disease (AD). The mitochondrial involvement in neurodegenerative diseases reflects the regulatory role mitochondrial failure plays in both necrotic cell death and apoptosis. The potent feminizing hormone, 17 beta-estradiol (E2), is neuroprotective in a host of cell and animal models of stroke and neurodegenerative diseases. The discovery that 17alpha-estradiol, an isomer of E2, is equally as neuroprotective as E2 yet is >200-fold less active as a hormone, has permitted development of novel, more potent analogs where neuroprotection is independent of hormonal potency. Studies of structure-activity relationships and mitochondrial function have led to a mechanistic model in which these steroidal phenols intercalate into cell membranes where they block lipid peroxidation reactions, and are in turn recycled. Indeed, the parental estrogens and novel analogs stabilize mitochondria under Ca(2+) loading otherwise sufficient to collapse membrane potential. The neuroprotective and mitoprotective potencies for a series of estrogen analogs are significantly correlated, suggesting that these compounds prevent cell death in large measure by maintaining functionally intact mitochondria. This therapeutic strategy is germane not only to sudden mitochondrial failure in acute circumstances, such as during a stroke or myocardial infarction, but also to gradual mitochondrial dysfunction associated with chronic degenerative disorders such as AD.
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Affiliation(s)
- James W Simpkins
- Department of Pharmacology and Neuroscience, Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, 3500 Camp Bowie Boul., Fort Worth, TX 76102, USA.
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Singh M, Dykens JA, Simpkins JW. Novel mechanisms for estrogen-induced neuroprotection. Exp Biol Med (Maywood) 2006; 231:514-21. [PMID: 16636299 DOI: 10.1177/153537020623100505] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Estrogens are gonadal steroid hormones that are present in the circulation of both males and females and that can no longer be considered within the strict confines of reproductive function. In fact, the bone, the cardiovascular system, and extrahypothalamic regions of the brain are now well-established targets of estrogens. Among the numerous aspects of brain function regulated by estrogens are their effects on mood, cognitive function, and neuronal viability. Here, we review the supporting evidence for estrogens as neuroprotective agents and summarize the various mechanisms that may be involved in this effect, focusing particularly on the mitochondria as an important target. On the basis of this evidence, we discuss the clinical applicability of estrogens in treating various age-related disorders, including Alzheimer disease and stroke, and identify the caveats that must be considered.
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Affiliation(s)
- Meharvan Singh
- Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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10
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Wang X, Dykens JA, Perez E, Liu R, Yang S, Covey DF, Simpkins JW. Neuroprotective effects of 17beta-estradiol and nonfeminizing estrogens against H2O2 toxicity in human neuroblastoma SK-N-SH cells. Mol Pharmacol 2006; 70:395-404. [PMID: 16614138 DOI: 10.1124/mol.106.022384] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuroprotective effects of estrogens have been shown in various in vitro and in vivo models, but the mechanisms underlying protection by estrogen are not clear. Mounting evidence suggests antioxidant effects contribute to the neuroprotective effects of estrogens. In the present study, we assessed the protective effects of estrogens against H2O2-induced toxicity in human neuroblastoma cells and the potential mechanisms involved in this protection. We demonstrate that 17beta-estradiol (17beta-E2) increases cell survival against H2O2 toxicity in human neuroblastoma cells. 17beta-E2 effectively reduced lipid peroxidation induced by 5-min H2O2 exposure. Furthermore, 17beta-E2 exerts the protective effects by maintaining intracellular Ca2+ homeostasis, attenuating ATP depletion, ablating mitochondrial calcium overloading, and preserving mitochondrial membrane potential. Two nonfeminizing estrogens, 17alpha- and ent-estradiol, were as effective as 17beta-E2 in increasing cell survival, alleviating lipid peroxidation, preserving mitochondrial function, and maintaining intracellular glutathione levels and Ca2+ homeostasis against H2O2 insult. Moreover, the estrogen receptor antagonist fulvestrant (ICI 182,780) did not block effects of 17beta-E2, but increased cell survival and blunted intracellular Ca2+ increases. However, these estrogens failed to reduce cytosolic reactive oxygen species, even at concentrations as high as 10 microM. In conclusion, estrogens exert protective effects against oxidative stress by inhibiting lipid peroxidation and subsequently preserving Ca2+ homeostasis, mitochondrial membrane potential, and ATP levels.
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Affiliation(s)
- Xiaofei Wang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA
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11
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Berg D. Marker for a preclinical diagnosis of Parkinson's disease as a basis for neuroprotection. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2006:123-32. [PMID: 17447423 DOI: 10.1007/978-3-211-33328-0_14] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Neuroprotective therapy is a pivotal aim in the treatment of the relentlessly progressive disorder Parkinson's disease. However, more than 60% of the dopaminergic neurons of the substantia nigra have already degenerated, when the diagnosis may be established. At this "advanced stage" neuroprotective strategies will - if at all - only have limited effect. It is, therefore, essential to establish markers to identify subjects at risk before motor manifestation. A number of such "premotor" signs have been discovered and investigated lately. Such signs include a genetic vulnerability and hyperechogenicity of the substantia nigra as well as premotor symptoms like olfactory and autonomic dysfunction, depression, REM sleep behaviour disorder, visual and neuropsychological impairment. Moreover, first signs of affection of the substantia nigra like PET and SPECT abnormalities and slight motor signs can be included, as they may be detected before a definite diagnosis can be made. Although most of these signs and symptoms are unspecific if singularly evaluated a combination of these features may indeed be valuable to detect a subgroup of the population at risk for PD. However, future studies are necessary to establish the predictive value of these "markers" singularly and in combination.
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Affiliation(s)
- Daniela Berg
- Hertie Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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12
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Dykens JA, Carroll AK, Wiley S, Covey DF, Cai ZY, Zhao L, Wen R. Photoreceptor preservation in the S334ter model of retinitis pigmentosa by a novel estradiol analog. Biochem Pharmacol 2005; 68:1971-84. [PMID: 15476668 DOI: 10.1016/j.bcp.2004.06.042] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Accepted: 06/15/2004] [Indexed: 11/29/2022]
Abstract
The cytoprotective activity of MITO-4565, a novel, non-hormonal, estradiol derivative, was evaluated in the S334ter transgenic model of retinitis pigmentosa (RP). Progressive blindness in RP is due to apoptotic death of the photoreceptors, a process mimicked by the animal models [Portera-Cailliau C, Sung C-H, Nathans J, Adler R. Apoptotic photoreceptor cell death in mouse models of retinitis pigmentosa. Proc Natl Acad Sci USA 1994;91:974-8]. On postnatal day 9, 10 transgenic S334ter rats received a single intraocular injection of MITO-4565 in the left eye, and vehicle in the right eye. By postnatal day 20, the thickness of the outer nuclear layer (ONL) in the superior retina of the untreated eyes was 5.76 +/- 1.12 microm (N = 10), versus 10.72 +/- 1.52 microm (N = 10) for eyes treated with MITO-4565 (P < 0.0001, ANOVA F = 1671). Comparable cytoprotection was also observed for the inferior retina. Cytoprotection by MITO-4565 was also observed in primary cultures of rat retinal ganglion cells against NMDA excitotoxicity. Data from studies of hexose monophosphate shunt flux, mitochondrial stability, and in vitro lipid peroxidation, are in accord with previous reports [Green PS, Gridley KE, Simpkins JW. Nuclear estrogen receptor independent neuroprotection by estratrienes: a novel interaction with glutathione. Neuroscience 1997;84:7-10]; a likely mechanism of action entails moderation of membrane lipid peroxidation in a redox couple with glutathione. Such preservation of membrane integrity is particularly crucial to mitochondria, where collapse of membrane potential precipitates cell death, and where GSH is maintained at mM concentrations. Indeed, exposure to MITO-4565, but not a methoxy substituted negative control, allowed mitochondria to retain membrane potential (DeltaPsi(m)) under conditions of Ca(2+) overload that would normally induce complete mitochondrial failure. Mitochondrial interventions offer a novel therapeutic approach for RP, and other degenerative diseases of the retina.
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Affiliation(s)
- James A Dykens
- MitoKor Inc., 11494 Sorrento Valley Road, San Diego, CA 92121, USA.
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Jung ME, Rewal M, Perez E, Wen Y, Simpkins JW. Estrogen protects against brain lipid peroxidation in ethanol-withdrawn rats. Pharmacol Biochem Behav 2004; 79:573-86. [PMID: 15582030 DOI: 10.1016/j.pbb.2004.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 09/09/2004] [Accepted: 09/10/2004] [Indexed: 11/18/2022]
Abstract
This study examined whether 17beta-estradiol (E2) administration protects against ethanol withdrawal (EW)-associated oxidative insults by assessing oxidative markers thiobarbituric-acid-reacting-substances (TBARS). Ovariectomized rats implanted with E2 (EW/E2) or oil pellets (EW/Oil) received chronic ethanol (7.5% wt./vol., 5 weeks) or control dextrin diet (Dextrin/Oil). At 24 or 48 h of EW, rats were tested for overt EW signs and the cerebellum, hippocampus, and cortex were prepared for TBARS assessment in the presence and absence of FeCl3. For control experiments, we assessed E2 effects on blood ethanol concentrations and TBARS levels during ethanol exposure prior to EW. The EW/Oil group showed enhanced endogenous- and FeCl3-stimulated membrane TBARS levels in the cerebellum and hippocampus in a manner inhibited by E2 treatment. There was a relationship between the severity of EW and elevation of TBARS levels, particularly in the cerebellum. The enhanced TBARS levels at 24 h of EW appeared to diminish at 48 h in the hippocampus, but persisted in the cerebellum. E2 treatment did not alter blood ethanol concentrations and ethanol exposure alone did not enhance TBARS levels. These data suggest that EW rather than ethanol enhances brain lipid peroxidation that is transient and brain-region specific. Estrogens protect against the brain lipid peroxidation in a manner independent of blood ethanol concentrations.
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Affiliation(s)
- Marianna E Jung
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
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Götz ME, Riederer P. Advances in Neuroprotection Research for Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 541:1-19. [PMID: 14977205 DOI: 10.1007/978-1-4419-8969-7_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mario E Götz
- Institute of Pharmacology and Toxicology, 97078 Würzburg, Germany
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Dhandapani KM, Brann DW. Protective effects of estrogen and selective estrogen receptor modulators in the brain. Biol Reprod 2002; 67:1379-85. [PMID: 12390866 DOI: 10.1095/biolreprod.102.003848] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Within the last few years, there has been a growing interest in the neuroprotective effects of estrogen and the possible beneficial effects of estrogen in neurodegenerative diseases such as stroke, Alzheimer disease, and Parkinson disease. Here, we review the progress in this field, with a particular focus upon estrogen-induced protection from stroke-induced ischemic damage. The important issue of whether clinically relevant selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene and estrogen replacement therapy can exert neuroprotection is also addressed. Although the mechanism of estrogen and SERM neuroprotection is not clearly resolved, we summarize the leading possibilities, including 1) a genomic estrogen receptor-mediated pathway that involves gene transcription, 2) a nongenomic signaling pathway involving activation of cell signalers such as mitogen-activated protein kinases and/or phosphatidylinositol-3-kinase /protein kinase B, and 3) a nonreceptor antioxidant free-radical scavenging pathway that is primarily observed with pharmacological doses of estrogen. The role of other potential mediatory factors such as growth factors and the possibility of an astrocyte role in neuroprotection is also discussed.
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Affiliation(s)
- Krishnan M Dhandapani
- Institute of Molecular Medicine and Genetics, Program in Neurobiology, and Department of Neurology, Medical College of Georgia, Augusta, Georgia 30912, USA
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16
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Furuta S, Ortiz F, Zhu Sun X, Wu HH, Mason A, Momand J. Copper uptake is required for pyrrolidine dithiocarbamate-mediated oxidation and protein level increase of p53 in cells. Biochem J 2002; 365:639-48. [PMID: 11964141 PMCID: PMC1222712 DOI: 10.1042/bj20011251] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2001] [Revised: 04/05/2002] [Accepted: 04/19/2002] [Indexed: 01/01/2023]
Abstract
The p53 tumour-suppressor protein is a transcription factor that activates the expression of genes involved in cell cycle arrest, apoptosis and DNA repair. The p53 protein is vulnerable to oxidation at cysteine thiol groups. The metal-chelating dithiocarbamates, pyrrolidine dithiocarbamate (PDTC), diethyldithiocarbamate, ethylene(bis)dithiocarbamate and H(2)O(2) were tested for their oxidative effects on p53 in cultured human breast cancer cells. Only PDTC oxidized p53, although all oxidants tested increased the p53 level. Inductively coupled plasma MS analysis indicated that the addition of 60 microM PDTC increased the cellular copper concentration by 4-fold, which was the highest level of copper accumulated amongst all the oxidants tested. Bathocuproinedisulphonic acid, a membrane-impermeable Cu(I) chelator inhibited the PDTC-mediated copper accumulation. Bathocuproinedisulphonic acid as well as the hydroxyl radical scavenger d-mannitol inhibited the PDTC-dependent increase in p53 protein and oxidation. Our results show that a low level of copper accumulation in the range of 25-40 microg/g of cellular protein increases the steady-state levels of p53. At copper accumulation levels higher than 60 microg/g of cellular protein, p53 is oxidized. These results suggest that p53 is vulnerable to free radical-mediated oxidation at cysteine residues.
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Affiliation(s)
- Saori Furuta
- Department of Chemistry and Biochemistry, California State University at Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, U.S.A
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17
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Abstract
Various neurodegenerative disorders and syndromes are associated with oxidative stress. The deleterious consequences of excessive oxidations and the pathophysiological role of reactive oxygen species (ROS) have been intensively studied in Alzheimer's disease (AD). Neuronal cell dysfunction and oxidative cell death caused by the AD-associated amyloid beta protein may causally contribute to the pathogenesis of AD. Antioxidants that prevent the detrimental consequences of ROS are consequently considered to be a promising approach to neuroprotection. While there is ample experimental evidence demonstrating neuroprotective activities of antioxidants in vitro, the clinical evidence that antioxidant compounds act as protective drugs is still relatively scarce. Nevertheless, antioxidants constitute a major part of the panel of clinical and experimental drugs that are currently considered for AD prevention and therapy. Here, focus is put mainly on phenolic antioxidant structures that belong to the class of direct antioxidants. Experimental and clinical evidence for the neuroprotective potential of alpha-tocopherol (vitamin E) and 17beta-estradiol (estrogen) is shortly summarized and an outlook is given on possible novel antioxidant lead structures with improved pharmacological features.
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Behl C, Moosmann B. Oxidative nerve cell death in Alzheimer's disease and stroke: antioxidants as neuroprotective compounds. Biol Chem 2002; 383:521-36. [PMID: 12033440 DOI: 10.1515/bc.2002.053] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many neurodegenerative disorders and syndromes are associated with an excessive generation of reactive oxygen species (ROS) and oxidative stress. The pathways to nerve cell death induced by diverse potential neurotoxins such as peptides, excitatory amino acids, cytokines or synthetic drugs commonly share oxidative downstream processes, which can cause either an acute oxidative destruction or activate secondary events leading to apoptosis. The pathophysiological role of ROS has been intensively studied in in vitro and in vivo models of chronic neurodegenerative diseases such as Alzheimer's disease (AD) and of syndromes associated with rapid nerve cell loss as occuring in stroke. In AD, oxidative neuronal cell dysfunction and cell death caused by protofibrils and aggregates of the AD-associated amyloid beta protein (Abeta) may causally contribute to pathogenesis and progression. ROS and reactive nitrogen species also take part in the complex cascade of events and the detrimental effects occuring during ischemia and reperfusion in stroke. Direct antioxidants such as chain-breaking free radical scavengers can prevent oxidative nerve cell death. Although there is ample experimental evidence demonstrating neuroprotective activities of direct antioxidants in vitro, the clinical evidence for antioxidant compounds to act as protective drugs is relatively scarce. Here, the neuroprotective potential of antioxidant phenolic structures including alpha-tocopherol (vitamin E) and 17beta-estradiol (estrogen) in vitro is summarized. In addition, the antioxidant and cytoprotective activities of lipophilic tyrosine- and tryptophan-containing structures are discussed. Finally, an outlook is given on the neuroprotective potential of aromatic amines and imines, which may comprise novel lead structures for antioxidant drug design.
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Chronic Alcohol Consumption and Cerebral Indices of Oxidative Stress: Is There a Link? Alcohol Clin Exp Res 2001. [DOI: 10.1097/00000374-200105000-00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gotz ME, Janetzky B, Pohli S, Gottschalk A, Gsell W, Tatschner T, Ransmayr G, Leblhuber F, Gerlach M, Reichmann H, Riederer P, Boning J. Chronic Alcohol Consumption and Cerebral Indices of Oxidative Stress: Is There a Link? Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02272.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Green PS, Simpkins JW. Estrogens and estrogen-like non-feminizing compounds. Their role in the prevention and treatment of Alzheimer's disease. Ann N Y Acad Sci 2001; 924:93-8. [PMID: 11193809 DOI: 10.1111/j.1749-6632.2000.tb05566.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present position paper is intended to provide evidence that estrogen deprivation contributes to the occurrence and course of Alzheimer's disease (AD) and that currently available estrogen preparations may be useful in the prevention and treatment of AD in women. Additionally, there is now substantial preclinical evidence to support the development of novel non-feminizing estrogens for use in male and female subjects for the protection of neurons from damage and death that underlies the neuropathology of AD. Estrogens and non-feminizing estrogen-like compounds may exert their beneficial effects in AD through a variety of mechanisms, directly through their neuroprotective actions and indirectly through their neurotrophic effects. Inasmuch as estrogens are comparatively free of both acute and chronic toxicities, and non-feminizing estrogens are expected to be even safer, their use for years to decades for the prevention or treatment of AD is possible.
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Affiliation(s)
- P S Green
- Center for the Neurobiology of Aging, College of Pharmacy, University of Florida, Gainesville, Florida 32610, USA
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22
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Abstract
Epidemiological studies associate post-menopausal estrogen use with a reduction in risk of Alzheimer's disease, a reduction in risk of Parkinson's disease, and death from stroke. The neuroprotective efficacy of estrogens have been well described and may contribute to these clinical effects. Estrogen-mediated neuroprotection has been described in several neuronal culture model systems with toxicities including serum-deprivation, beta-amyloid-induced toxicity, excitotoxicity, and oxidative stress. In animal models, estrogens have been shown to attenuate neuronal death in rodent models of cerebral ischemia, traumatic injury, and Parkinson's disease. Although estrogens are known to exert several direct effects on neurons, the cellular mechanisms behind the neuroprotective efficacy of the steroid are only beginning to be elucidated. In this review, we summarize the data supporting a neuroprotective role for estrogens in both culture and animal models and discuss neuronal effects of estrogens that may contribute to the neuroprotective effects. These effects include activation of the nuclear estrogen receptor, altered expression of bcl-2 and related proteins, activation of the mitogen activated kinase pathway, activation of cAMP signal transduction pathways, modulation of intracellular calcium homeostasis, and direct antioxidant activity.
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Affiliation(s)
- P S Green
- Center for the Neurobiology of Aging, Department of Pharmcodynamics, University of Florida, Box 100487, JHMHC, Gainesville, USA
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23
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Roof RL, Hall ED. Gender differences in acute CNS trauma and stroke: neuroprotective effects of estrogen and progesterone. J Neurotrauma 2000; 17:367-88. [PMID: 10833057 DOI: 10.1089/neu.2000.17.367] [Citation(s) in RCA: 472] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Increasing evidence has demonstrated striking sex differences in the pathophysiology of and outcome after acute neurological injury. Lesser susceptibility to postischemic and posttraumatic brain injury in females has been observed in experimental models. Additional evidence suggests this sex difference extends to humans as well. The greater neuroprotection afforded to females is likely due to the effects of circulating estrogens and progestins. In fact, exogenous administration of both hormones has been shown to improve outcome after cerebral ischemia and traumatic brain injury in experimental models. The neuroprotection provided by periinjury administration of these hormones extends to males as well. The mechanisms by which estrogen and progesterone provide such neuroprotection are likely multifactorial, and probably depend on the type and severity of injury as well as the type and concentration of hormone present. Both genomic and nongenomic mechanisms may be involved. Estrogen's putative effects include preservation of autoregulatory function, an antioxidant effect, reduction of A beta production and neurotoxicity, reduced excitotoxicity, increased expression of the antiapoptotic factor bcl-2, and activation of mitogen activated protein kinase pathways. It is hypothesized that several of these neuroprotective mechanisms can be linked back to estrogen's ability to act as a potent chemical (i.e., electron-donating) antioxidant. Progesterone, on the other hand, has a membrane stabilizing effect that also serves to reduce the damage caused by lipid peroxidation. In addition, it may also provide neuroprotection by suppressing neuronal hyperexcitability. The following review will discuss experimental and clinical evidence for sex differences in outcome after acute brain trauma and stroke, review the evidence implicating estrogens and progestins as mediators of this neuroprotection following acute neurological injury, and finally, address the specific mechanisms by which these hormones may protect the brain following acute neurological injury.
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Affiliation(s)
- R L Roof
- Neuroscience Therapeutics, Parke-Davis Pharmaceutical Research, Division of Warner-Lambert, Ann Arbor, Michigan 48105, USA.
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24
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Gerlach M, Double KL, Youdim MB, Riederer P. Strategies for the protection of dopaminergic neurons against neurotoxicity. Neurotox Res 2000; 2:99-114. [PMID: 16787835 DOI: 10.1007/bf03033788] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Degenerative diseases of the central nervous system (CNS) frequently have a predilection for specific cell populations. An explanation for the selective vulnerability of particular neuronal populations and the mechanisms of cell death remains, as yet, elusive. Partial elucidation of the processes underlying the selective action of neurotoxic substances such as iron, 6-hydroxydopamine (6-OHDA), glutamate, kainic acid, quinolinic acid or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), has revealed possible molecular mechanisms for neurodegeneration. Hypotheses regarding the neurotoxic mechanisms of these substances have evolved based on our understanding of the pathogenesis of cell death in neurodegenerative disorders and have been the rationale for neuroprotective approaches. Various experimental models have demonstrated that monoamine oxidase type B (MAO-B) inhibitors and dopamine agonists exert a neuroprotective effect at the cellular, neurochemical and functional levels, however as yet it has not been possible to demonstrate an unequivocal neuroprotective effect of these substances in clinical studies. This does not suggest, however, that the pathogenetic processes underlying neurodegenerative disorders are not amenable to neuroprotective treatment. This chapter briefly reviews the mechanisms underlying dopaminergic cell death in Parkinson's disease (PD) as an example of a neurodegenerative disorder and discusses preclinical approaches which attempt to demonstrate the neuroprotective effects of representative drugs in experimental models of this disorder. The problems associated with carrying out clinical neuroprotective studies aimed to demonstrate neuroprotection in PD are also discussed.
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Affiliation(s)
- M Gerlach
- Division of Clinical Neurochemistry, Department of Psychiatry and Psychotherapy, University of Würzburg, D-97980 Würzburg, Fuchsleinstrasse 15, Germany.
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25
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Götz ME, Ahlbom E, Zhivotovsky B, Blum-Degen D, Oettel M, Römer W, Riederer P, Orrenius S, Ceccatelli S. Radical scavenging compound J 811 inhibits hydrogen peroxide-induced death of cerebellar granule cells. J Neurosci Res 1999; 56:420-6. [PMID: 10340749 DOI: 10.1002/(sici)1097-4547(19990515)56:4<420::aid-jnr9>3.0.co;2-p] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Oxidative stress is considered to be an important pathophysiological condition to promote cell death in a broad variety of disorders, such as cardiovascular and neurodegenerative diseases. Scavestrogens, structurally derived from estradiol, are potent radical scavengers and inhibitors of iron-induced cell damage in vitro. In this study the potential cytoprotective effects of the so-called scavestrogen estra-1,3,5(10),8-tetraene-3,17alpha-diol, J 811, was tested using rat cerebellar granule cells (CGCs) exposed to 25 or 50 microM hydrogen peroxide (H2O2). H2O2-induced apoptotic cell death was detected by the appearance of high molecular weight DNA fragments and nuclear condensation. The addition of J 811 before or shortly after the exposure to H2O2 prevented CGC apoptosis in a dose-dependent manner. The estrogen receptor antagonist ICI 182.780 failed to prevent the protective effect of J 811, suggesting that the latter is not dependent on estrogen receptor activation. The lack of protection against apoptosis caused by colchicine suggests that J 811 is neither interfering with the activation of caspase-3, nor acting downstream of caspase-3. Therefore, the protective effect observed against H2O2 seems to be upstream caspases activation, pointing to a scavenging action of J 811. Thus the scavestrogen J 811 is a powerful antioxidant able to interfere with radical-mediated cell death and is potentially useful in diseases where reactive oxygen species are involved.
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Affiliation(s)
- M E Götz
- Karolinska Institutet, Institute of Environmental Medicine, Stockholm, Sweden.
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