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Zhang T, Zhang Z, Geng J, Lin K, Lin X, Jiao M, Zhu J, Guo X, Lin Z. A New Approach for Exploring Reperfusion Brain Damage in Hypoxic Ischemic Encephalopathy. Mol Neurobiol 2024; 61:1417-1432. [PMID: 37721688 DOI: 10.1007/s12035-023-03645-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/05/2023] [Indexed: 09/19/2023]
Abstract
Reperfusion is an essential pathological stage in hypoxic ischemic encephalopathy (HIE). Although the Rice-Vannucci model is widely used in HIE research, it remains difficult to replicate HIE-related reperfusion brain injury. The purpose of this study is to establish a rat model of hypoxia ischemia reperfusion brain damage (HIRBD) using a common carotid artery (CCA) muscle bridge in order to investigate the mechanisms of cerebral resistance to hypoxic-ischemic and reperfusion brain damage. Random assignment of Sprague-Dawley (SD) rats to the Sham, HIRBD, and Rice-Vannucci groups. Changes in body weight, mortality rate, spontaneous alternation behavior test (SAB test), and dynamic changes in cerebral blood flow (CBF) were detected. The damaged cerebral cortices were extracted for morphological comparison, transcriptomic analysis, and quantitative real-time PCR. Harvesting the hippocampus for transmission electron microscopy (TEM) detection. As a result, CCA muscle bridge could effectively block CBF, which recovered after the muscle bridge detachment. Pathological comparison, the SAB test, and TEM analysis revealed that brain damage in Rice-Vannucci was more severe than HIRBD. Gpx1, S100a6, Cldn5, Esr1, and Gfap were highly expressed in both HIRBD and Rice-Vannucci. In conclusion, the CCA muscle bridge-established HIRBD model could be used as an innovative and dependable model to simulate pathological process of HIRBD.
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Affiliation(s)
- Tianlei Zhang
- Department of Pediatrics, the Second School of Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Zhiwei Zhang
- Second Clinical Medical College, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jiayi Geng
- Second Clinical Medical College, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Kexin Lin
- Second Clinical Medical College, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Xinru Lin
- Second Clinical Medical College, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Mengdie Jiao
- Department of Pediatrics, the Second School of Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jianghu Zhu
- Department of Pediatrics, the Second School of Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
- Key Laboratory of Children Genitourinary Diseases of Wenzhou, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
| | - Xiaoling Guo
- Department of Pediatrics, the Second School of Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
- Key Laboratory of Perinatal Medicine of Wenzhou, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
- Basic Medical Research Center, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
| | - Zhenlang Lin
- Department of Pediatrics, the Second School of Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
- Second Clinical Medical College, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
- Key Laboratory of Children Genitourinary Diseases of Wenzhou, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
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Covey DF, Evers AS, Izumi Y, Maguire JL, Mennerick SJ, Zorumski CF. Neurosteroid enantiomers as potentially novel neurotherapeutics. Neurosci Biobehav Rev 2023; 149:105191. [PMID: 37085023 PMCID: PMC10750765 DOI: 10.1016/j.neubiorev.2023.105191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
Endogenous neurosteroids and synthetic neuroactive steroids (NAS) are important targets for therapeutic development in neuropsychiatric disorders. These steroids modulate major signaling systems in the brain and intracellular processes including inflammation, cellular stress and autophagy. In this review, we describe studies performed using unnatural enantiomers of key neurosteroids, which are physiochemically identical to their natural counterparts except for rotation of polarized light. These studies led to insights in how NAS interact with receptors, ion channels and intracellular sites of action. Certain effects of NAS show high enantioselectivity, consistent with actions in chiral environments and likely direct interactions with signaling proteins. Other effects show no enantioselectivity and even reverse enantioselectivity. The spectrum of effects of NAS enantiomers raises the possibility that these agents, once considered only as tools for preclinical studies, have therapeutic potential that complements and in some cases may exceed their natural counterparts. Here we review studies of NAS enantiomers from the perspective of their potential development as novel neurotherapeutics.
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Affiliation(s)
- Douglas F Covey
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; Anesthesiology Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Alex S Evers
- Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; Anesthesiology Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Yukitoshi Izumi
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Steven J Mennerick
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles F Zorumski
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
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Sørvik IB, Solum EJ, Labba NA, Hansen TV, Paulsen RE. Differential effects of some novel synthetic oestrogen analogs on oxidative PC12 cell death caused by serum deprivation. Free Radic Res 2018; 52:273-287. [DOI: 10.1080/10715762.2018.1430363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Irene B. Sørvik
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Eirik Johansson Solum
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Nils A. Labba
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Trond Vidar Hansen
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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Sørvik IB, Paulsen RE. High and low concentration of 17α-estradiol protect cerebellar granule neurons in different time windows. Biochem Biophys Res Commun 2017. [DOI: 10.1016/j.bbrc.2017.06.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Guo JJ, Yang DP, Tian X, Vemuri VK, Yin D, Li C, Duclos RI, Shen L, Ma X, Janero DR, Makriyannis A. 17β-estradiol (E2) in membranes: Orientation and dynamic properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:344-53. [PMID: 26607010 DOI: 10.1016/j.bbamem.2015.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 11/27/2022]
Abstract
Non-genomic membrane effects of estrogens are of great interest because of the diverse biological activities they may elicit. To further our understanding of the molecular features of the interaction between estrogenic hormones and membrane bilayers, we have determined the preferred orientation, location, and dynamic properties of 17β-estradiol (E2) in two different phospholipid membrane environments using (2)H-NMR and 2D (1)H-(13)C HSQC in conjunction with molecular dynamics simulations. Unequivocal spectral assignments to specific (2)H labels were made possible by synthesizing six selectively deuterated E2 molecules. The data allow us to conclude that the E2 molecule adopts a nearly "horizontal" orientation in the membrane bilayer with its long axis essentially perpendicular to the lipid acyl-chains. All four rings of the E2 molecule are located near the membrane interface, allowing both the E2 3-OH and the 17β-OH groups to engage in hydrogen bonding and electrostatic interactions with polar phospholipid groups. The findings augment our knowledge of the molecular interactions between E2 and membrane bilayer and highlight the asymmetric nature of the dynamic motions of the rigid E2 molecule in a membrane environment.
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Affiliation(s)
- Jason J Guo
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA.
| | - De-Ping Yang
- Physics Department, College of the Holy Cross, 1 College Street, Worcester, MA 01610, USA
| | - Xiaoyu Tian
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - V Kiran Vemuri
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Dali Yin
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Chen Li
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Richard I Duclos
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Lingling Shen
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Xiaoyu Ma
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - David R Janero
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA; Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA.
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Akhter H, Ballinger C, Liu N, van Groen T, Postlethwait EM, Liu RM. Cyclic Ozone Exposure Induces Gender-Dependent Neuropathology and Memory Decline in an Animal Model of Alzheimer's Disease. Toxicol Sci 2015; 147:222-34. [PMID: 26116027 DOI: 10.1093/toxsci/kfv124] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Alzheimer's disease (AD) is a major cause of dementia in the elderly. Although early-onset (familial) AD is attributed to gene mutations, the cause for late-onset (sporadic) AD, which accounts for 95% of AD cases, is unknown. In this study, we show that exposure of 6-week-old amyloid beta precursor protein (APP)/presenilin (PS1) overexpressing mice, a well-established animal model of AD, and nontransgenic littermates to a cyclic O3 exposure protocol, which mimics environmental exposure episodes, accelerated learning/memory function loss in male APP/PS1 mice but not in female APP/PS1 mice or nontransgenic littermates. Female APP/PS1 mice had higher brain levels of amyloid beta peptide (Aβ42) and Aβ40, compared with male APP/PS1 mice; O3 exposure, however, had no significant effect on brain Aβ load in either male or female mice. Our results further show that male APP/PS1 mice had lower levels of antioxidants (glutathione and ascorbate) and experienced augmented induction of NADPH oxidases, lipid peroxidation, and neuronal apoptosis upon O3 exposure, compared with female APP/PS1 mice. No significant effect of O3 on any of these parameters was detected in nontransgenic littermates. In vitro studies further show that 4-hydroxynonenal, a lipid peroxidation product which was increased in the plasma and cortex/hippocampus of O3-exposed male APP/PS1 mice, induced neuroblastoma cell apoptosis. Together, the results suggest that O3 exposure per se may not cause AD but can synergize with genetic risk factors to accelerate the pathophysiology of AD in genetically predisposed populations. The results also suggest that males may be more sensitive to O3-induced neuropathophysiology than females due to lower levels of antioxidants.
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Affiliation(s)
| | | | - Nianjun Liu
- Department of Biostatistics, School of Public Health
| | | | | | - Rui-Ming Liu
- *Department of Environmental Health Sciences, Division of Pulmonary, Allergy, and Critical Care Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294
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Petrone AB, Gatson JW, Simpkins JW, Reed MN. Non-feminizing estrogens: a novel neuroprotective therapy. Mol Cell Endocrinol 2014; 389:40-7. [PMID: 24424441 PMCID: PMC4040321 DOI: 10.1016/j.mce.2013.12.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/17/2013] [Accepted: 12/17/2013] [Indexed: 12/16/2022]
Abstract
While the conflict between basic science evidence for estrogen neuroprotection and the lack of effectiveness in clinical trials is only now being resolved, it is clear that strategies for estrogen neuroprotection that avoid activation of ERs have the potential for clinical application. Herein we review the evidence from both in vitro and in vivo studies that describe high potency neuroprotection with non-feminizing estrogens. We have characterized many of the essential chemical features of non-feminizing estrogens that eliminate or reduce ER binding while maintaining or enhancing neuroprotection. Additionally, we provide evidence that these non-feminizing estrogens have efficacy in protecting the brain from AD neuropathology and traumatic brain injury. In conclusion, it appears that the non-feminizing estrogen strategy for neuroprotection is a viable option to achieve the beneficial neuroprotective effects of estrogens while eliminating the toxic off-target effects of chronic estrogen administration.
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Affiliation(s)
- Ashley B Petrone
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, WV, United States; Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV, United States
| | - Joshua W Gatson
- Department of Emergency Medicine, University of Texas Southwestern Medical School, Dallas, TX, United States
| | - James W Simpkins
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, WV, United States; Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV, United States
| | - Miranda N Reed
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV, United States; Department of Psychology, West Virginia University, Morgantown, WV, United States.
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Sorwell KG, Urbanski HF. Causes and consequences of age-related steroid hormone changes: insights gained from nonhuman primates. J Neuroendocrinol 2013; 25:1062-9. [PMID: 23796387 PMCID: PMC3883982 DOI: 10.1111/jne.12064] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 01/23/2023]
Abstract
Similar to humans, rhesus macaques (Macaca mulatta) are large, long-lived diurnal primates, and show similar age-related changes in the secretion of many steroid hormones, including oestradiol, testosterone, cortisol and dehydroepiandrosterone (DHEA). Consequently, they represent a pragmatic animal model in which to examine the mechanisms by which these steroidal changes contribute to perturbed sleep-wake cycles and cognitive decline in the elderly. Using remote serial blood sampling, we have found the circulating levels of DHEA sulphate, as well as oestradiol and testosterone, decline markedly in old monkeys. Furthermore, using the real-time polymerase chain reaction, we have shown that the genes for the enzymes associated with the conversion of DHEA to oestradiol and testosterone (3β-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase, and aromatase) are highly expressed in brain areas associated with cognition and behaviour, including the hippocampus, prefrontal cortex and amygdala. Taken together, these findings suggest that the administration of supplementary DHEA in the elderly may have therapeutic potential for cognitive and behavioural disorders, although with fewer negative side effects outside of the central nervous system. To test this, we have developed a novel steroid supplementation paradigm for use in old animals; this involves the oral administration of DHEA and testosterone at physiologically relevant times of the day to mimic the circadian hormone patterns observed in young adults. We are currently evaluating the efficacy of this steroid supplementation paradigm with respect to reversing age-associated disorders, including perturbed sleep-wake cycles and cognitive decline, as well as an impaired immune response.
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Affiliation(s)
- K G Sorwell
- Departments of Neuroscience and Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
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Chen KC, Blalock EM, Curran-Rauhut MA, Kadish I, Blalock SJ, Brewer L, Porter NM, Landfield PW. Glucocorticoid-dependent hippocampal transcriptome in male rats: pathway-specific alterations with aging. Endocrinology 2013; 154:2807-20. [PMID: 23736296 PMCID: PMC3713214 DOI: 10.1210/en.2013-1139] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Although glucocorticoids (GCs) are known to exert numerous effects in the hippocampus, their chronic regulatory functions remain poorly understood. Moreover, evidence is inconsistent regarding the long-standing hypothesis that chronic GC exposure promotes brain aging/Alzheimer disease. Here, we adrenalectomized male F344 rats at 15 months of age, maintained them for 3 months with implanted corticosterone (CORT) pellets producing low or intermediate (glucocorticoid receptor-activating) blood levels of CORT, and performed microarray/pathway analyses in hippocampal CA1. We defined the chronic GC-dependent transcriptome as 393 genes that exhibited differential expression between intermediate and low CORT groups. Short-term CORT (4 days) did not recapitulate this transcriptome. Functional processes/pathways overrepresented by chronic CORT-up-regulated genes included learning/plasticity, differentiation, glucose metabolism, and cholesterol biosynthesis, whereas processes overrepresented by CORT-down-regulated genes included inflammatory/immune/glial responses and extracellular structure. These profiles indicate that GCs chronically activate neuronal/metabolic processes while coordinately repressing a glial axis of reactivity/inflammation. We then compared the GC transcriptome with a previously defined hippocampal aging transcriptome, revealing a high proportion of common genes. Although CORT and aging moved expression of some common genes in the same direction, the majority were shifted in opposite directions by CORT and aging (eg, glial inflammatory genes down-regulated by CORT are up-regulated with aging). These results contradict the hypothesis that GCs simply promote brain aging and also suggest that the opposite direction shifts during aging reflect resistance to CORT regulation. Therefore, we propose a new model in which aging-related GC resistance develops in some target pathways, whereas GC overstimulation develops in others, together generating much of the brain aging phenotype.
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Affiliation(s)
- Kuey-Chu Chen
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Estrogen regulation of Dkk1 and Wnt/β-Catenin signaling in neurodegenerative disease. Brain Res 2012; 1514:63-74. [PMID: 23261660 DOI: 10.1016/j.brainres.2012.12.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/11/2012] [Indexed: 11/22/2022]
Abstract
17β-estradiol (E2 or estrogen) is an endogenous steroid hormone that is well known to exert neuroprotection. Along these lines, one mechanism through which E2 protects the hippocampus from cerebral ischemia is by preventing the post-ischemic elevation of Dkk1, a neurodegenerative factor that serves as an antagonist of the canonical Wnt signaling pathway, and simultaneously inducing pro-survival Wnt/β-Catenin signaling in hippocampal neurons. Intriguingly, while expression of Dkk1 is required for proper neural development, overexpression of Dkk1 is characteristic of many neurodegenerative diseases, such as stroke, Alzheimer's disease, Parkinson's disease, and temporal lobe epilepsy. In this review, we will briefly summarize the canonical Wnt signaling pathway, highlight the current literature linking alterations of Dkk1 and Wnt/β-Catenin signaling with neurological disease, and discuss E2's role in maintaining the delicate balance of Dkk1 and Wnt/β-Catenin signaling in the adult brain. Finally, we will consider the implications of long-term E2 deprivation and hormone therapy on this crucial neural pathway. This article is part of a Special Issue entitled Hormone Therapy.
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