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Hasegawa S, Watanabe S, Fujimoto S, Kondo S, Nishi T. Characterization of soticlestat, a novel cholesterol 24-hydroxylase inhibitor, in acute and chronic neurodegeneration models. Neurosci Res 2024:S0168-0102(24)00077-4. [PMID: 38897234 DOI: 10.1016/j.neures.2024.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/05/2024] [Accepted: 06/14/2024] [Indexed: 06/21/2024]
Abstract
We investigated whether soticlestat (TAK-935), a newly discovered cholesterol 24-hydroxylase (CH24H) inhibitor now in phase 3 clinical trials for Dravet and Lennox-Gastaut syndromes, has effects on neurodegeneration in both chronic and acute animal models associated with glutamate hyperexcitation. Soticlestat was administered at doses that approximately halve 24S-hydroxycholesterol in both experiments. In the kainic acid (KA)-induced acute hippocampal degeneration model, soticlestat ameliorated inflammatory cytokine expression, hippocampal degeneration, and memory impairment. We ruled out the possibility that soticlestat directly interferes with KA binding to the KA receptor, or that 24S-hydroxycholesterol modulates KA receptor signaling, by conducting receptor binding and cell death assays. In the PS19 chronic degeneration model of tauopathy, treatment effects were observed in neurodegeneration markers. Notably, there was a significant correlation between the levels of brain 24S-hydroxycholesterol and a proinflammatory cytokine, tumor necrosis factor-α, which is implicated in cognitive decline and lowering of seizure threshold. This is the first study demonstrating that CH24H inhibition can alleviate neurodegeneration concomitant with neuroinflammation. Herein, we discuss the interplay among 24S-hydroxycholesterol production, neuroinflammation, and excitotoxicity. Effects on neurodegeneration and neuroinflammation demonstrated in two preclinical models suggest that soticlestat is effective in ameliorating seizures and addressing cognitive dysfunction in seizure disorders.
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Affiliation(s)
- Shigeo Hasegawa
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka Higashi, Fujisawa 251-8555, Japan.
| | - Sayuri Watanabe
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka Higashi, Fujisawa 251-8555, Japan.
| | - Shinji Fujimoto
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka Higashi, Fujisawa 251-8555, Japan.
| | - Shinichi Kondo
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka Higashi, Fujisawa 251-8555, Japan.
| | - Toshiya Nishi
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka Higashi, Fujisawa 251-8555, Japan.
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Petrov AM. Oxysterols in Central and Peripheral Synaptic Communication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:91-123. [PMID: 38036877 DOI: 10.1007/978-3-031-43883-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Cholesterol is a key molecule for synaptic transmission, and both central and peripheral synapses are cholesterol rich. During intense neuronal activity, a substantial portion of synaptic cholesterol can be oxidized by either enzymatic or non-enzymatic pathways to form oxysterols, which in turn modulate the activities of neurotransmitter receptors (e.g., NMDA and adrenergic receptors), signaling molecules (nitric oxide synthases, protein kinase C, liver X receptors), and synaptic vesicle cycling involved in neurotransmitters release. 24-Hydroxycholesterol, produced by neurons in the brain, could directly affect neighboring synapses and change neurotransmission. 27-Hydroxycholesterol, which can cross the blood-brain barrier, can alter both synaptogenesis and synaptic plasticity. Increased generation of 25-hydroxycholesterol by activated microglia and macrophages could link inflammatory processes to learning and neuronal regulation. Amyloids and oxidative stress can lead to an increase in the levels of ring-oxidized sterols and some of these oxysterols (4-cholesten-3-one, 5α-cholestan-3-one, 7β-hydroxycholesterol, 7-ketocholesterol) have a high potency to disturb or modulate neurotransmission at both the presynaptic and postsynaptic levels. Overall, oxysterols could be used as "molecular prototypes" for therapeutic approaches. Analogs of 24-hydroxycholesterol (SGE-301, SGE-550, SAGE718) can be used for correction of NMDA receptor hypofunction-related states, whereas inhibitors of cholesterol 24-hydroxylase, cholestane-3β,5α,6β-triol, and cholest-4-en-3-one oxime (olesoxime) can be utilized as potential anti-epileptic drugs and (or) protectors from excitotoxicity.
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Affiliation(s)
- Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, RT, Russia.
- Kazan State Medial University, Kazan, RT, Russia.
- Kazan Federal University, Kazan, RT, Russia.
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Wu S, Zhang YF, Gui Y, Jiang T, Zhou CM, Li JY, Suo JL, Li YN, Jin RL, Li SL, Cui JY, Tan BH, Li YC. A detection method for neuronal death indicates abnormalities in intracellular membranous components in neuronal cells that underwent delayed death. Prog Neurobiol 2023; 226:102461. [PMID: 37179048 DOI: 10.1016/j.pneurobio.2023.102461] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/20/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023]
Abstract
Acute neuronal degeneration is always preceded under the light and electron microscopes by a stage called microvacuolation, which is characterized by a finely vacuolar alteration in the cytoplasm of the neurons destined to death. In this study, we reported a method for detecting neuronal death using two membrane-bound dyes, rhodamine R6 and DiOC6(3), which may be associated with the so-called microvacuolation. This new method produced a spatiotemporally similar staining pattern to Fluoro-Jade B in kainic acid-damaged brains in mice. Further experiments showed that increased staining of rhodamine R6 and DiOC6(3) was observed only in degenerated neurons, but not in glia, erythrocytes, or meninges. Different from Fluoro-Jade-related dyes, rhodamine R6 and DiOC6(3) staining is highly sensitive to solvent extraction and detergent exposure. Staining with Nile red for phospholipids and filipin III for non-esterified cholesterol supports that the increased staining of rhodamine R6 and DiOC6(3) might be associated with increased levels of phospholipids and free cholesterol in the perinuclear cytoplasm of damaged neurons. In addition to kainic acid-injected neuronal death, rhodamine R6 and DiOC6(3) were similarly useful for detecting neuronal death in ischemic models either in vivo or in vitro. As far as we know, the staining with rhodamine R6 or DiOC6(3) is one of a few histochemical methods for detecting neuronal death whose target molecules have been well defined and therefore may be useful for explaining experimental results as well as exploring the mechanisms of neuronal death. (250 words).
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Affiliation(s)
- Shuang Wu
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Yan-Feng Zhang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, Jilin Province 130021, PR China
| | - Yue Gui
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Tian Jiang
- Department of Emergency and Critical Care Medicine, The Second Hospital of Jilin University, Jilin Province 130041, PR China
| | - Cheng-Mei Zhou
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Jing-Yi Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Jia-Le Suo
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Yong-Nan Li
- Department of Neurology, Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province 150001, PR China
| | - Rui-Lin Jin
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Shu-Lei Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Jia-Yue Cui
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Bai-Hong Tan
- Laboratory Teaching Center of Basic Medicine, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China
| | - Yan-Chao Li
- Department of Histology and Embryology, College of Basic Medical Sciences, Norman Bethune Health Science Center of Jilin University, Jilin Province 130021, PR China.
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Ong WY, Leow DMK, Herr DR, Yeo CJJ. What Do Randomized Controlled Trials Inform Us About Potential Disease-Modifying Strategies for Parkinson's Disease? Neuromolecular Med 2023; 25:1-13. [PMID: 35776238 DOI: 10.1007/s12017-022-08718-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/05/2022] [Indexed: 01/09/2023]
Abstract
Research advances have shed new insight into cellular pathways contributing to PD pathogenesis and offer increasingly compelling therapeutic targets. In this review, we made a broad survey of the published literature that report possible disease-modifying effects on PD. While there are many studies that demonstrate benefits for various therapies for PD in animal and human studies, we confined our search to human "randomised controlled trials" and with the key words "neuroprotection" or "disease-modifying". It is hoped that through studying the results of these trials, we might clarify possible mechanisms that underlie idiopathic PD. This contrasts with studying the effect of pathophysiology of familial PD, which could be carried out by gene knockouts and animal models. Randomised controlled trials indicate promising effects of MAO-B inhibitors, dopamine agonists, NMDA receptor antagonists, metabotropic glutamate receptor antagonists, therapies related to improving glucose utilization and energy production, therapies related to reduction of excitotoxicity and oxidative stress, statin use, therapies related to iron chelation, therapies related to the use of phytochemicals, and therapies related to physical exercise and brain reward pathway on slowing PD progression. Cumulatively, these approaches fall into two categories: direct enhancement of dopaminergic signalling, and reduction of neurodegeneration. Overlaps between the two categories result in challenges in distinguishing between symptomatic versus disease-modifying effects with current clinical trial designs. Nevertheless, a broad-based approach allows us to consider all possible therapeutic avenues which may be neuroprotective. While the traditional standard of care focuses on symptomatic management with dopaminergic drugs, more recent approaches suggest ways to preserve dopaminergic neurons by attenuating excitotoxicity and oxidative stress.
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Affiliation(s)
- Wei-Yi Ong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore.
- Neurobiology Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore.
| | - Damien Meng-Kiat Leow
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore
| | - Deron R Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore
| | - Crystal Jing-Jing Yeo
- Institute of Molecular and Cell Biology, A*Star, Singapore, 138673, Singapore
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Evanston, IL, USA
- LKC School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
- National Neuroscience Institute, Singapore, 308433, Singapore
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Cataldi GG, Elorza SD, Toledano-Zaragoza A, de Olmos S, Cragnolini AB, Martín MG. Cholesterol-24-hydroxylase (CYP46) in the old brain: Analysis of positive populations and factors triggering its expression in astrocytes. J Comp Neurol 2023; 531:486-499. [PMID: 36453552 DOI: 10.1002/cne.25436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 12/05/2022]
Abstract
Cholesterol-24-hydroxylase (CYP46), a member of the cytochrome P450 superfamily of enzymes, is selectively expressed in the brain and is mainly responsible for cholesterol turnover in the central nervous system. Although increased cyp46A1 gene expression has been linked to cognitive alterations in aging and observed in neurodegenerative diseases and after traumatic brain injury, a detailed characterization of the brain regions and cell types in which CYP46 is expressed in old individuals has not been performed. Using immunohistochemistry and immunofluorescence, we investigated the specific regions and cell populations in the brain, in which cyp46A1 is expressed in 24-month-old mice. We found that CYP46 is localized in the same neuronal populations in young and old brains, mainly in the hippocampus, in cortical layers, and in Purkinje neurons of the cerebellum. No increase in CYP46 levels was found in astrocytes in old mice brains, in primary astrocyte-neuron cocultures aged in vitro, or in primary cultures of senescent astrocytes. However, interleukin-6 treatment strongly induced cyp46A1 expression in reactive astrocytes characterized by high GFAP levels but had no effect in nonactivated astrocytes. Our data suggest that cholesterol-24-hydroxylase expression is triggered in reactive astrocytes in response to proinflammatory signals, probably as part of a response mechanism to injury.
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Affiliation(s)
- Gabriel G Cataldi
- Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Setiembre D Elorza
- Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ana Toledano-Zaragoza
- Molecular Neuropathology Unit, Physiological and Pathological Processes Program, Centro de Biología Molecular Severo Ochoa (CBMSO-CSIC), Madrid, Spain
| | - Soledad de Olmos
- Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea B Cragnolini
- Instituto de Investigaciones Biológicas y Tecnológicas, CONICET-UNC, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mauricio G Martín
- Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
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Proteomics reveals the key molecules involved in curcumin-induced protection against sciatic nerve injury in rats. Neuroscience 2022; 501:11-24. [PMID: 35870565 DOI: 10.1016/j.neuroscience.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 11/23/2022]
Abstract
We generated a rat model of sciatic nerve crush injury and characterized the effects of curcumin on sciatic nerve recovery by using behavioral experiments, hematoxylin-eosin staining, toluidine blue staining, and immunohistochemical. Proteomic analysis using tandem mass tagging was performed to determine differentially expressed proteins (DEPs), and GO and KEGG pathway analyses of overlapping DEPs was conducted, following which, qPCR, western blotting, and immunofluorescence were further performed to validate the proteins of interest. Finally, a Schwann cell injury model was used to verify the effect of curcumin on potential targets. The rat model was successful established and curcumin improved the sciatic nerve function index of rats with sciatic nerve injury (SNI) and increased the number and diameter of myelinated axons in the sciatic nerve. In the Sham group versus the Injured group and in the Injured group versus the Curcumin group, we identified a total of 4,175 proteins, of which 953 were DEPs, and 218 were known overlapping DEPs. Ten associated pathways, such as calcium signaling pathway, biosynthesis of antibiotics, and long-term potentiation, were identified. The 218 overlapping DEPs were primarily involved in negative regulation of apoptotic process, biological processes, cytoplasm cellular component, and protein binding molecular function based on GO annotation. Curcumin promoted increased expression of ApoD and inhibited the expression of Cyba in vivo and in vitro. These results indicated that curcumin promoted sciatic nerve repair through regulation of various proteins, targets, and pathways. Cyba and ApoD may be potential targets of curcumin in the treatment of SNI.
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Dave AM, Peeples ES. Cholesterol metabolism and brain injury in neonatal encephalopathy. Pediatr Res 2021; 90:37-44. [PMID: 33106607 PMCID: PMC8511855 DOI: 10.1038/s41390-020-01218-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 01/05/2023]
Abstract
Neonatal encephalopathy (NE) results from impaired cerebral blood flow and oxygen delivery to the brain. The pathophysiology of NE is complex and our understanding of its underlying pathways continues to evolve. There is considerable evidence that cholesterol dysregulation is involved in several adult diseases, including traumatic brain injury, stroke, Huntington's disease, and Parkinson's disease. Although the research is less robust in pediatrics, there is emerging evidence that aberrations in cholesterol metabolism may also be involved in the pathophysiology of neonatal NE. This narrative review provides an overview of cholesterol metabolism in the brain along with several examples from the adult literature where pathologic alterations in cholesterol metabolism have been associated with inflammatory and ischemic brain injury. Using those data as a background, the review then discusses the current preclinical data supporting the involvement of cholesterol in the pathogenesis of NE as well as how brain-specific cholesterol metabolites may serve as serum biomarkers for brain injury. Lastly, we review the potential for using the cholesterol metabolic pathways as therapeutic targets. Further investigation of the shifts in cholesterol synthesis and metabolism after hypoxia-ischemia may prove vital in understanding NE pathophysiology as well as providing opportunities for rapid diagnosis and therapeutic interventions. IMPACT: This review summarizes emerging evidence that aberrations in cholesterol metabolism may be involved in the pathophysiology of NE. Using data from NE as well as analogous adult disease states, this article reviews the potential for using cholesterol pathways as targets for developing novel therapeutic interventions and using cholesterol metabolites as biomarkers for injury. When possible, gaps in the current literature were identified to aid in the development of future studies to further investigate the interactions between cholesterol pathways and NE.
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Affiliation(s)
- Amanda M Dave
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, USA
| | - Eric S Peeples
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, USA.
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Effect of Ergothioneine on 7-Ketocholesterol-Induced Endothelial Injury. Neuromolecular Med 2020; 23:184-198. [PMID: 33067719 PMCID: PMC7567423 DOI: 10.1007/s12017-020-08620-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022]
Abstract
Ergothioneine (ET) is a naturally occurring antioxidant that is synthesized by non-yeast fungi and certain bacteria. ET is not synthesized by animals, including humans, but is avidly taken up from the diet, especially from mushrooms. In the current study, we elucidated the effect of ET on the hCMEC/D3 human brain endothelial cell line. Endothelial cells are exposed to high levels of the cholesterol oxidation product, 7-ketocholesterol (7KC), in patients with cardiovascular disease and diabetes, and this process is thought to mediate pathological inflammation. 7KC induces a dose-dependent loss of cell viability and an increase in apoptosis and necrosis in the endothelial cells. A relocalization of the tight junction proteins, zonula occludens-1 (ZO-1) and claudin-5, towards the nucleus of the cells was also observed. These effects were significantly attenuated by ET. In addition, 7KC induces marked increases in the mRNA expression of pro-inflammatory cytokines, IL-1β IL-6, IL-8, TNF-α and cyclooxygenase-2 (COX2), as well as COX2 enzymatic activity, and these were significantly reduced by ET. Moreover, the cytoprotective and anti-inflammatory effects of ET were significantly reduced by co-incubation with an inhibitor of the ET transporter, OCTN1 (VHCL). This shows that ET needs to enter the endothelial cells to have a protective effect and is unlikely to act via extracellular neutralizing of 7KC. The protective effect on inflammation in brain endothelial cells suggests that ET might be useful as a nutraceutical for the prevention or management of neurovascular diseases, such as stroke and vascular dementia. Moreover, the ability of ET to cross the blood-brain barrier could point to its usefulness in combatting 7KC that is produced in the CNS during neuroinflammation, e.g. after excitotoxicity, in chronic neurodegenerative diseases, and possibly COVID-19-related neurologic complications.
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4-Hydroxyestrone, an Endogenous Estrogen Metabolite, Can Strongly Protect Neuronal Cells Against Oxidative Damage. Sci Rep 2020; 10:7283. [PMID: 32350290 PMCID: PMC7190733 DOI: 10.1038/s41598-020-62984-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 03/18/2020] [Indexed: 11/08/2022] Open
Abstract
Earlier studies showed that endogenous estrogens have neuroprotective effect against oxidative damage. The present study seeks to investigate the protective effect of various endogenous estrogen metabolites against oxidative neurotoxicity in vitro and in vivo. Using immortalized mouse hippocampal neuronal cells as an in vitro model, 4-hydroxyestrone, an estrone metabolite with little estrogenic activity, is found to have the strongest neuroprotective effect against oxidative neurotoxicity among 25 endogenous estrogen metabolites tested, and its protective effect is stronger than 17β-estradiol. Similarly, 4-Hydroxyestrone also exerts a stronger protective effect than 17β-estradiol against kanic acid-induced hippocampal oxidative damage in rats. Neuroprotection by 4-hydroxyestrone involves increased cytoplasmic translocation of p53 resulting from SIRT1-mediated deacetylation of p53. Analysis of brain microsomal enzymes shows that estrogen 4-hydroxylation is the main metabolic pathway in the central nervous system. Together, these results show that 4-hydroxyestrone is an endogenous neuroestrogen that can strongly protect against oxidative neuronal damage.
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Abdanipour A, Deheshjo F, Sohrabi D, Jafari Anarkooli I, Nejatbakhsh R. Neuroprotective effect of lovastatin through down-regulation of pro-apoptotic Mst1 gene expression in rat model pilocarpine epilepsy. Neurol Res 2018; 40:874-882. [PMID: 30048231 DOI: 10.1080/01616412.2018.1497252] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Statins as inhibitors of HMG-CoA reductase have been recently recognized as anti-inflammatory and neuroprotective drugs. In this paper, we studied anti-apoptotic and regulatory effects of lovastatin using Pilocarpine rat model through downregulation of Mst1 (Mammalian sterile 20-like kinase 1) as a novel pro-apoptotic gene. METHODS The rats were divided into four groups: non-treated epileptic rats, lovastatin treated, and two vehicle groups. Racine scale was used for behavioral assessment and animals with a score of 4-5 were selected for the study. After 3 days, epileptic rats received intraperitoneal injections of lovastatin, followed by treating for 14 days. Next, they were sacrificed (28 post-first seizure) and prepared for histopathological analysis and Real-time RT-PCR. RESULTS The results showed that lovastatin protects Pilocarpine-induced cell death via a regulatory effect on pro-apoptotic and anti-apoptotic gene expression. The real-time PCR results showed that in the epileptic lovastatin treated group, the expression level of Mst1 significantly decreased while Nrf2 and Bcl-2 genes increased. Furthermore, histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic cells significantly decreased in the treatment groups. The results showed that the numerical density of neurons per area was significantly higher in the treated than the untreated group. CONCLUSION Overall, the results of this study showed that lovastatin attenuates hippocampal cell death in Pilocarpine-induced status epilepticus rat model through downregulation of the pro-apoptotic Mst1 gene. ABBREVIATIONS Mst1: Mammalian sterile 20-like kinase 1; Nrf2: nuclear factor erythroid 2-related factor 2; Bcl-2: B-cell lymphoma 2; HMG-CoA: 3-hydroxy-3-methylglutaryl-coenzyme A; RT-PCR: reverse transcription-polymerase chain reaction; TLE: Temporal Lobe Epilepsy; SE: status epilepticus.
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Affiliation(s)
- Alireza Abdanipour
- a Department of Anatomy, School of Medicine , Zanjan University of Medical Sciences (ZUMS) , Zanjan , Iran
| | - Fatemeh Deheshjo
- a Department of Anatomy, School of Medicine , Zanjan University of Medical Sciences (ZUMS) , Zanjan , Iran
| | - Davood Sohrabi
- a Department of Anatomy, School of Medicine , Zanjan University of Medical Sciences (ZUMS) , Zanjan , Iran
| | - Iraj Jafari Anarkooli
- a Department of Anatomy, School of Medicine , Zanjan University of Medical Sciences (ZUMS) , Zanjan , Iran
| | - Reza Nejatbakhsh
- a Department of Anatomy, School of Medicine , Zanjan University of Medical Sciences (ZUMS) , Zanjan , Iran
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11
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Yu IC, Kuo PC, Yen JH, Paraiso HC, Curfman ET, Hong-Goka BC, Sweazey RD, Chang FL. A Combination of Three Repurposed Drugs Administered at Reperfusion as a Promising Therapy for Postischemic Brain Injury. Transl Stroke Res 2017. [PMID: 28624878 DOI: 10.1007/s12975-017-0543-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cerebral ischemia leads to multifaceted injury to the brain. A polytherapeutic drug that can be administered immediately after reperfusion may increase protection to the brain by simultaneously targeting multiple deleterious cascades. This study evaluated efficacy of the combination of three clinically approved drugs: lamotrigine, minocycline, and lovastatin, using two mouse models: global and focal cerebral ischemia induced by transient occlusion of the common carotid arteries or the middle cerebral artery, respectively. In vitro, the combination drug, but not single drug, protected neurons against oxygen-glucose deprivation (OGD)-induced cell death. The combination drug simultaneously targeted cell apoptosis and DNA damage induced by ischemia. Besides acting on neurons, the combination drug suppressed inflammatory processes in microglia and brain endothelial cells induced by ischemia. In a transient global ischemia model, the combination drug, but not single drug, suppressed microglial activation and inflammatory cytokine production, and reduced neuronal damage. In a transient focal ischemia model, the combination drug, but not single drug, attenuated brain infarction, suppressed infiltration of peripheral neutrophils, and reduced neurological deficits following ischemic stroke. In summary, the combination drug confers a broad-spectrum protection against ischemia/reperfusion (I/R) injury and could be a promising approach for early neuroprotection after out-of-hospital cardiac arrest or ischemic stroke.
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Affiliation(s)
- I-Chen Yu
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA.
| | - Ping-Chang Kuo
- Department of Microbiology and Immunology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Jui-Hung Yen
- Department of Microbiology and Immunology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Hallel C Paraiso
- Department of Biology, Indiana University-Purdue University Fort Wayne, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Eric T Curfman
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Benecia C Hong-Goka
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Robert D Sweazey
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA
| | - Fen-Lei Chang
- Department of Neurology, Indiana University School of Medicine, 2101 E. Coliseum Boulevard, Fort Wayne, IN, 46805, USA.
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Expression profiles of cholesterol metabolism-related genes are altered during development of experimental autoimmune encephalomyelitis in the rat spinal cord. Sci Rep 2017; 7:2702. [PMID: 28578430 PMCID: PMC5457442 DOI: 10.1038/s41598-017-02638-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/12/2017] [Indexed: 12/04/2022] Open
Abstract
Increased evidence suggests that dysregulation of cholesterol metabolism may be a key event contributing to progression of multiple sclerosis (MS). Using an experimental autoimmune encephalomyelitis (EAE) model of MS we revealed specific changes in the mRNA and protein expression of key molecules involved in the maintaining of cholesterol homeostasis in the rat spinal cord: 3-hydroxy-3-methylglutaryl-coenzyme-A reductase (HMGCR), apolipoprotein E (ApoE) and cholesterol 24-hydroxylase (CYP46A1) during the course of disease. The presence of myelin lipid debris was seen only at the peak of EAE in demyelination loci being efficiently removed during the recovery period. Since CYP46A1 is responsible for removal of cholesterol excess, we performed a detailed profiling of CYP46A1 expression and revealed regional and temporal specificities in its distribution. Double immunofluorescence staining demonstrated CYP46A1 localization with neurons, infiltrated macrophages, microglia and astrocytes in the areas of demyelination, suggesting that these cells play a role in cholesterol turnover in EAE. We propose that alterations in the regulation of cholesterol metabolism at the onset and peak of EAE may add to the progression of disease, while during the recovery period may have beneficial effects contributing to the regeneration of myelin sheath and restoration of neuronal function.
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Klemann CJHM, Martens GJM, Sharma M, Martens MB, Isacson O, Gasser T, Visser JE, Poelmans G. Integrated molecular landscape of Parkinson's disease. NPJ PARKINSONS DISEASE 2017. [PMID: 28649614 PMCID: PMC5460267 DOI: 10.1038/s41531-017-0015-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Parkinson’s disease is caused by a complex interplay of genetic and environmental factors. Although a number of independent molecular pathways and processes have been associated with familial Parkinson’s disease, a common mechanism underlying especially sporadic Parkinson’s disease is still largely unknown. In order to gain further insight into the etiology of Parkinson’s disease, we here conducted genetic network and literature analyses to integrate the top-ranked findings from thirteen published genome-wide association studies of Parkinson’s disease (involving 13.094 cases and 47.148 controls) and other genes implicated in (familial) Parkinson’s disease, into a molecular interaction landscape. The molecular Parkinson’s disease landscape harbors four main biological processes—oxidative stress response, endosomal-lysosomal functioning, endoplasmic reticulum stress response, and immune response activation—that interact with each other and regulate dopaminergic neuron function and death, the pathological hallmark of Parkinson’s disease. Interestingly, lipids and lipoproteins are functionally involved in and influenced by all these processes, and affect dopaminergic neuron-specific signaling cascades. Furthermore, we validate the Parkinson’s disease -lipid relationship by genome-wide association studies data-based polygenic risk score analyses that indicate a shared genetic risk between lipid/lipoprotein traits and Parkinson’s disease. Taken together, our findings provide novel insights into the molecular pathways underlying the etiology of (sporadic) Parkinson’s disease and highlight a key role for lipids and lipoproteins in Parkinson’s disease pathogenesis, providing important clues for the development of disease-modifying treatments of Parkinson’s disease. Lipids and lipoproteins play a central role in four key biological processes underlying Parkinson’s disease (PD). Using bioinformatics and other extensive analyses of previously published data, Geert Poelmans, Cornelius Klemann and colleagues in The Netherlands, Germany and the USA have mapped the interactions of proteins that are encoded by genes associated with both familial and sporadic forms of PD. They identify the oxidative stress response, lysosomal function, endoplasmic reticulum stress response and immune response activation as the main mechanisms leading to the death of dopaminergic neurons. Lipid signaling is implicated in all four of these processes and the authors find a link between the levels of particular lipids and lipoproteins and the risk of PD. These findings suggest that compounds that regulate lipid or lipoprotein levels offer a potential new treatment strategy for PD.
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Affiliation(s)
- C J H M Klemann
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University, Nijmegen, The Netherlands
| | - G J M Martens
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University, Nijmegen, The Netherlands
| | - M Sharma
- Centre for Genetic Epidemiology, Institute for Clinical Epidemiology and Applied Biometry, University of Tübingen, Tübingen, Germany
| | - M B Martens
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - O Isacson
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Belmont, MA USA
| | - T Gasser
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research, University of Tübingen, and German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - J E Visser
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University, Nijmegen, The Netherlands.,Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Neurology, Amphia Hospital, Breda, The Netherlands
| | - G Poelmans
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University, Nijmegen, The Netherlands.,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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Moutinho M, Nunes MJ, Rodrigues E. Cholesterol 24-hydroxylase: Brain cholesterol metabolism and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1911-1920. [PMID: 27663182 DOI: 10.1016/j.bbalip.2016.09.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/05/2016] [Accepted: 09/16/2016] [Indexed: 01/19/2023]
Abstract
Dysfunctions in brain cholesterol homeostasis have been extensively related to brain disorders. The major elimination pathway of brain cholesterol is its hydroxylation into 24 (S)-hydroxycholesterol by the cholesterol 24-hydroxylase (CYP46A1). Interestingly, there seems to be an association between CYP46A1 and high-order brain functions, in a sense that increased expression of this hydroxylase improves cognition, while a reduction leads to a poor cognitive performance. Moreover, increasing amount of epidemiological, biochemical and molecular evidence, suggests that CYP46A1 has a role in the pathogenesis or progression of neurodegenerative disorders, in which up-regulation of this enzyme is clearly beneficial. However, the mechanisms underlying these effects are poorly understood, which highlights the importance of studies that further explore the role of CYP46A1 in the central nervous system. In this review we summarize the major findings regarding CYP46A1, and highlight the several recently described pathways modulated by this enzyme from a physiological and pathological perspective, which might account for novel therapeutic strategies for neurodegenerative disorders.
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Affiliation(s)
- Miguel Moutinho
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Maria João Nunes
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Elsa Rodrigues
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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Changes in brain oxysterols at different stages of Alzheimer's disease: Their involvement in neuroinflammation. Redox Biol 2016; 10:24-33. [PMID: 27687218 PMCID: PMC5040635 DOI: 10.1016/j.redox.2016.09.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/07/2016] [Accepted: 09/09/2016] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is a gradually debilitating disease that leads to dementia. The molecular mechanisms underlying AD are still not clear, and at present no reliable biomarkers are available for the early diagnosis. In the last several years, together with oxidative stress and neuroinflammation, altered cholesterol metabolism in the brain has become increasingly implicated in AD progression. A significant body of evidence indicates that oxidized cholesterol, in the form of oxysterols, is one of the main triggers of AD. The oxysterols potentially most closely involved in the pathogenesis of AD are 24-hydroxycholesterol and 27-hydroxycholesterol, respectively deriving from cholesterol oxidation by the enzymes CYP46A1 and CYP27A1. However, the possible involvement of oxysterols resulting from cholesterol autooxidation, including 7-ketocholesterol and 7β-hydroxycholesterol, is now emerging. In a systematic analysis of oxysterols in post-mortem human AD brains, classified by the Braak staging system of neurofibrillary pathology, alongside the two oxysterols of enzymatic origin, a variety of oxysterols deriving from cholesterol autoxidation were identified; these included 7-ketocholesterol, 7α-hydroxycholesterol, 4β-hydroxycholesterol, 5α,6α-epoxycholesterol, and 5β,6β-epoxycholesterol. Their levels were quantified and compared across the disease stages. Some inflammatory mediators, and the proteolytic enzyme matrix metalloprotease-9, were also found to be enhanced in the brains, depending on disease progression. This highlights the pathogenic association between the trends of inflammatory molecules and oxysterol levels during the evolution of AD. Conversely, sirtuin 1, an enzyme that regulates several pathways involved in the anti-inflammatory response, was reduced markedly with the progression of AD, supporting the hypothesis that the loss of sirtuin 1 might play a key role in AD. Taken together, these results strongly support the association between changes in oxysterol levels and AD progression.
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Najyb O, Do Carmo S, Alikashani A, Rassart E. Apolipoprotein D Overexpression Protects Against Kainate-Induced Neurotoxicity in Mice. Mol Neurobiol 2016; 54:3948-3963. [PMID: 27271124 PMCID: PMC7091089 DOI: 10.1007/s12035-016-9920-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 05/03/2016] [Indexed: 01/23/2023]
Abstract
Excitotoxicity due to the excessive activation of glutamatergic receptors leads to neuronal dysfunction and death. Excitotoxicity has been implicated in the pathogenesis of a myriad of neurodegenerative diseases with distinct etiologies such as Alzheimer's and Parkinson's. Numerous studies link apolipoprotein D (apoD), a secreted glycoprotein highly expressed in the central nervous system (CNS), to maintain and protect neurons in various mouse models of acute stress and neurodegeneration. Here, we used a mouse model overexpressing human apoD in neurons (H-apoD Tg) to test the neuroprotective effects of apoD in the kainic acid (KA)-lesioned hippocampus. Our results show that apoD overexpression in H-apoD Tg mice induces an increased resistance to KA-induced seizures, significantly attenuates inflammatory responses and confers protection against KA-induced cell apoptosis in the hippocampus. The apoD-mediated protection against KA-induced toxicity is imputable in part to increased plasma membrane Ca2+ ATPase type 2 expression (1.7-fold), decreased N-methyl-D-aspartate receptor (NMDAR) subunit NR2B levels (30 %) and lipid metabolism alterations. Indeed, we demonstrate that apoD can attenuate intracellular cholesterol content in primary hippocampal neurons and in brain of H-apoD Tg mice. In addition, apoD can be internalised by neurons and this internalisation is accentuated in ageing and injury conditions. Our results provide additional mechanistic information on the apoD-mediated neuroprotection in neurodegenerative conditions.
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Affiliation(s)
- Ouafa Najyb
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-ville, Montréal, QC, H3C-3P8, Canada
| | - Sonia Do Carmo
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-ville, Montréal, QC, H3C-3P8, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Azadeh Alikashani
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-ville, Montréal, QC, H3C-3P8, Canada
| | - Eric Rassart
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-ville, Montréal, QC, H3C-3P8, Canada.
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The impairment of cholesterol metabolism in Huntington disease. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1095-105. [DOI: 10.1016/j.bbalip.2014.12.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/19/2014] [Accepted: 12/21/2014] [Indexed: 02/02/2023]
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Gamba P, Testa G, Gargiulo S, Staurenghi E, Poli G, Leonarduzzi G. Oxidized cholesterol as the driving force behind the development of Alzheimer's disease. Front Aging Neurosci 2015; 7:119. [PMID: 26150787 PMCID: PMC4473000 DOI: 10.3389/fnagi.2015.00119] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/03/2015] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD), the most common neurodegenerative disorder associated with dementia, is typified by the pathological accumulation of amyloid Aβ peptides and neurofibrillary tangles (NFT) within the brain. Considerable evidence indicates that many events contribute to AD progression, including oxidative stress, inflammation, and altered cholesterol metabolism. The brain’s high lipid content makes it particularly vulnerable to oxidative species, with the consequent enhancement of lipid peroxidation and cholesterol oxidation, and the subsequent formation of end products, mainly 4-hydroxynonenal and oxysterols, respectively from the two processes. The chronic inflammatory events observed in the AD brain include activation of microglia and astrocytes, together with enhancement of inflammatory molecule and free radical release. Along with glial cells, neurons themselves have been found to contribute to neuroinflammation in the AD brain, by serving as sources of inflammatory mediators. Oxidative stress is intimately associated with neuroinflammation, and a vicious circle has been found to connect oxidative stress and inflammation in AD. Alongside oxidative stress and inflammation, altered cholesterol metabolism and hypercholesterolemia also significantly contribute to neuronal damage and to progression of AD. Increasing evidence is now consolidating the hypothesis that oxidized cholesterol is the driving force behind the development of AD, and that oxysterols are the link connecting the disease to altered cholesterol metabolism in the brain and hypercholesterolemia; this is because of the ability of oxysterols, unlike cholesterol, to cross the blood brain barrier (BBB). The key role of oxysterols in AD pathogenesis has been strongly supported by research pointing to their involvement in modulating neuroinflammation, Aβ accumulation, and cell death. This review highlights the key role played by cholesterol and oxysterols in the brain in AD pathogenesis.
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Affiliation(s)
- Paola Gamba
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Simona Gargiulo
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Erica Staurenghi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin Orbassano, Torino, Italy
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Huo XL, Min JJ, Pan CY, Zhao CC, Pan LL, Gui FF, Jin L, Wang XT. Efficacy of lovastatin on learning and memory deficits caused by chronic intermittent hypoxia-hypercapnia: through regulation of NR2B-containing NMDA receptor-ERK pathway. PLoS One 2014; 9:e94278. [PMID: 24718106 PMCID: PMC3981803 DOI: 10.1371/journal.pone.0094278] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 03/14/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Chronic intermittent hypoxia-hypercapnia (CIHH) exposure leads to learnning and memory deficits in rats. Overactivation of N-methyl-D-aspartate receptors(NMDARs) can lead to the death of neurons through a process termed excitotoxicity, which is involved in CIHH-induced cognitive deficits. Excessively activated NR2B (GluN2B)-containing NMDARs was reported as the main cause of excitotoxicity. The ERK1/2 (extracellular signal-regulated kinase 1/2) signaling cascade acts as a key component in NMDARs-dependent neuronal plasticity and survival. Ca2+/calmodulin-dependent protein kinase II (CaMKII), synapse-associated protein 102 (SAP102) and Ras GTPase-activating protein (SynGAP) have been shown to be involved in the regulation of NMDAR-ERK signalling cascade. Recent studies revealed statins (the HMG-CoA reductase inhibitor) have effect on the expression of NMDARs. The present study intends to explore the potential effect of lovastatin on CIHH-induced cognitive deficits and the NR2B-ERK signaling pathway. METHODS AND FINDINGS Eighty male Sprague Dawley rats were randomly divided into five groups. Except for those in the control group, the rats were exposed to chronic intermittent hypoxia-hypercapnia (CIHH) (9 ∼ 11%O2, 5.5 ∼ 6.5%CO2) for 4 weeks. After lovastatin administration, the rats performed better in the Morris water maze test. Electron microscopy showed alleviated hippocampal neuronal synaptic damage. Further observation suggested that either lovastatin or ifenprodil (a selective NR2B antagonist) administration similarly downregulated NR2B subunit expression leading to a suppression of CaMKII/SAP102/SynGAP signaling cascade, which in turn enhanced the phosphorylation of ERK1/2. The phosphorylated ERK1/2 induced signaling cascade involving cAMP-response element-binding protein (CREB) phosphorylation and brain-derived neurotrophic factor (BDNF) activation, which is responsible for neuroprotection. CONCLUSIONS These findings suggest that the ameliorative cognitive deficits caused by lovastatin are due to the downregulation of excessive NR2B expression accompanied by increased expression of ERK signaling cascade. The effect of NR2B in upregulating pERK1/2 maybe due, at least in part, to inactivation of CaMKII/SAP102/SynGAP signaling cascade.
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Affiliation(s)
- Xin-long Huo
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jing-jing Min
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Cai-yu Pan
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Cui-cui Zhao
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Lu-lu Pan
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Fei-fei Gui
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Lu Jin
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiao-tong Wang
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Loke SY, Tanaka K, Ong WY. Comprehensive gene expression analyses of the rat prefrontal cortex after oxysterol treatment. J Neurochem 2013; 124:770-81. [DOI: 10.1111/jnc.12142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 02/06/2023]
Affiliation(s)
- Sau-Yeen Loke
- Department of Anatomy; National University of Singapore; Singapore
| | - Kazuhiro Tanaka
- Department of Physiology; National University of Singapore; Singapore
| | - Wei-Yi Ong
- Department of Anatomy; National University of Singapore; Singapore
- Neurobiology and Ageing Research Programme; National University of Singapore; Singapore
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21
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Kang KS, Yamabe N, Wen Y, Fukui M, Zhu BT. Beneficial effects of natural phenolics on levodopa methylation and oxidative neurodegeneration. Brain Res 2012. [PMID: 23206800 DOI: 10.1016/j.brainres.2012.11.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Levodopa (L-DOPA) is widely used for symptomatic management in Parkinson's disease. We recently showed that (-)-epigallocatechin-3-gallate, a tea polyphenol, not only inhibits L-DOPA methylation, but also protects against oxidative hippocampal neurodegeneration. In the present study, we sought to determine several other common dietary phenolics, namely, tea catechins [(+)-catechin and (-)-epicatechin] and a representative flavonoid (quercetin), for their ability to modulate L-DOPA methylation and to protect against oxidative hippocampal injury. A combination of in vitro biochemical assays, cell culture-based mechanistic analyses, and in vivo animal models was used. While both tea catechins and quercetin strongly inhibit human liver catechol-O-methyltransferase (COMT)-mediated O-methylation of L-DOPA in vitro, only (+)-catechin exerts a significant inhibition of L-DOPA methylation in both peripheral compartment and striatum in rats. The stronger in vivo effect of (+)-catechin on L-DOPA methylation compared to the other dietary compounds is due to its better bioavailability in vivo. In addition, (+)-catechin strongly reduces glutamate-induced oxidative cytotoxicity in HT22 mouse hippocampal neurons in vitro through inactivation of the nuclear factor-κB signaling pathway. Administration of (+)-catechin also exerts a strong neuroprotective effect in the kainic acid-induced oxidative hippocampal neurodegeneration model in rats. In conclusion, (+)-catechin is a dietary polyphenolic that may have beneficial effects in L-DOPA-based treatment of Parkinson patients by inhibiting L-DOPA methylation plus reducing oxidative neurodegeneration.
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Affiliation(s)
- Ki Sung Kang
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Leoni V, Caccia C. 24S-hydroxycholesterol in plasma: a marker of cholesterol turnover in neurodegenerative diseases. Biochimie 2012; 95:595-612. [PMID: 23041502 DOI: 10.1016/j.biochi.2012.09.025] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/20/2012] [Indexed: 01/09/2023]
Abstract
Brain cholesterol is mainly involved in the cell membrane structure, in signal transduction, neurotransmitter release, synaptogenesis and membrane trafficking. Impairment of brain cholesterol metabolism was described in neurodegenerative diseases, such as Multiple Sclerosis, Alzheimer and Huntington Diseases. Since the blood-brain barrier efficiently prevents cholesterol uptake from the circulation into the brain, de novo synthesis is responsible for almost all cholesterol present there. Cholesterol is converted into 24S-hydroxycholesterol (24OHC) by cholesterol 24-hydroxylase (CYP46A1) expressed in neural cells. Plasma concentration of 24OHC depends upon the balance between cerebral production and hepatic elimination and is related to the number of metabolically active neurons in the brain. Factors affecting brain cholesterol turnover and liver elimination of oxysterols, together with the metabolism of plasma lipoproteins, genetic background, nutrition and lifestyle habits were found to significantly affect its plasma levels. Either increased or decreased plasma 24OHC concentrations were described in patients with neurodegenerative diseases. A group of evidence suggests that reduced levels of 24OHC are related to the loss of metabolically active cells and the degree of brain atrophy. Inflammation, dysfunction of BBB, increased cholesterol turnover might counteract this tendency resulting in increased levels or, in some cases, in unsignificant changes. The study of plasma 24OHC is likely to offer an insight about brain cholesterol turnover with a limited diagnostic power.
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Affiliation(s)
- Valerio Leoni
- Laboratory of Clinical Pathology and Medical Genetics, Foundation IRCCS Institute of Neurology Carlo Besta, Milan, Italy.
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Heverin M, Engel T, Meaney S, Jimenez-Mateos EM, Al-Saudi R, Henshall DC. Bi-lateral changes to hippocampal cholesterol levels during epileptogenesis and in chronic epilepsy following focal-onset status epilepticus in mice. Brain Res 2012; 1480:81-90. [DOI: 10.1016/j.brainres.2012.08.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/17/2012] [Accepted: 08/08/2012] [Indexed: 01/18/2023]
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Cincioglu M, Kismali G, Ugur SA, Kelicen-Ugur P. Indinavir inhibits the expression of cytoplasmic aromatase and nuclear SREBP in the hippocampus of reperfusion injury-induced ischemic rats. J Steroid Biochem Mol Biol 2012; 130:81-9. [PMID: 22342839 DOI: 10.1016/j.jsbmb.2012.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 01/19/2012] [Accepted: 01/21/2012] [Indexed: 12/21/2022]
Abstract
Ischemic brain injury due to insults, such as stroke, is a leading cause of severe neurological and neurobehavioral deficits and death. Neurodegeneration can be prevented by local aromatase expression, and estrogen synthesis can be neuroprotective in ischemia/reperfusion. Therefore, aromatase, the enzyme that transforms androgens to estrogens, may be a potential target for the study of reperfusion injury after brain ischemia. We investigated the expression of aromatase and sterol regulatory element binding protein (SREBP) using Western blotting in the rat hippocampus after transient global ischemia plus hypotension. After 10 min of ischemia, aromatase and SREBP expression was observed in cytosolic extracts after 1, 4 and 10 weeks of reperfusion. Previous immunoblot analysis demonstrated that the highest aromatase expression appeared in damaged hippocampi after 1 week. In this study, SREBP expression was increased at 1 week in the nuclear extracts of damaged hippocampi. The aromatase inhibitor megestrol acetate (20 mg/kg/day; 21 days) and the SREBP inhibitor indinavir (15 mg/kg/day; 30 days) suppressed aromatase levels in ischemic hippocampi. Our findings indicate that ischemia, as well as chronic neurodegenerative processes, leads to an increase in cytoplasmic aromatase and nuclear SREBP. Thus, it is possible to hypothesize that an interaction between this enzyme gene and the transcription factor exists.
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Affiliation(s)
- Mehtap Cincioglu
- Department of Pharmacology, Faculty of Pharmacy, Hacettepe University, 06100 Ankara, Turkey
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Pfrieger FW, Ungerer N. Cholesterol metabolism in neurons and astrocytes. Prog Lipid Res 2011; 50:357-71. [PMID: 21741992 DOI: 10.1016/j.plipres.2011.06.002] [Citation(s) in RCA: 325] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 06/11/2011] [Accepted: 06/22/2011] [Indexed: 12/20/2022]
Abstract
Cells in the mammalian body must accurately maintain their content of cholesterol, which is an essential membrane component and precursor for vital signalling molecules. Outside the brain, cholesterol homeostasis is guaranteed by a lipoprotein shuttle between the liver, intestine and other organs via the blood circulation. Cells inside the brain are cut off from this circuit by the blood-brain barrier and must regulate their cholesterol content in a different manner. Here, we review how this is accomplished by neurons and astrocytes, two cell types of the central nervous system, whose cooperation is essential for normal brain development and function. The key observation is a remarkable cell-specific distribution of proteins that mediate different steps of cholesterol metabolism. This form of metabolic compartmentalization identifies astrocytes as net producers of cholesterol and neurons as consumers with unique means to prevent cholesterol overload. The idea that cholesterol turnover in neurons depends on close cooperation with astrocytes raises new questions that need to be addressed by new experimental approaches to monitor and manipulate cholesterol homeostasis in a cell-specific manner. We conclude that an understanding of cholesterol metabolism in the brain and its role in disease requires a close look at individual cell types.
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Affiliation(s)
- Frank W Pfrieger
- CNRS UPR 3212, University of Strasbourg, Institute of Cellular and Integrative Neurosciences (INCI), 67084 Strasbourg Cedex, France.
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Kim JH, Ee SM, Jittiwat J, Ong ES, Farooqui AA, Jenner AM, Ong WY. Increased expression of acyl-coenzyme A: cholesterol acyltransferase-1 and elevated cholesteryl esters in the hippocampus after excitotoxic injury. Neuroscience 2011; 185:125-34. [PMID: 21514367 DOI: 10.1016/j.neuroscience.2011.04.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/05/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
Abstract
Significant increases in levels of cholesterol and cholesterol oxidation products are detected in the hippocampus undergoing degeneration after excitotoxicity induced by the potent glutamate analog, kainate (KA), but until now, it is unclear whether the cholesterol is in the free or esterified form. The present study was carried out to examine the expression of the enzyme involved in cholesteryl ester biosynthesis, acyl-coenzyme A: cholesterol acyltransferase (ACAT) and cholesteryl esters after KA excitotoxicity. A 1000-fold greater basal mRNA level of ACAT1 than ACAT2 was detected in the normal brain. ACAT1 mRNA and protein were upregulated in the hippocampus at 1 and 2 weeks after KA injections, at a time of glial reaction. Immunohistochemistry showed ACAT1 labeling of oligodendrocytes in the white matter and axon terminals in hippocampal CA fields of normal rats, and loss of staining in neurons but increased immunoreactivity of oligodendrocytes, in areas affected by KA. Gas chromatography-mass spectrometry analyses confirmed previous observations of a marked increase in level of total cholesterol and cholesterol oxidation products, whilst nuclear magnetic resonance spectroscopy showed significant increases in cholesteryl ester species in the degenerating hippocampus. Upregulation of ACAT1 expression was detected in OLN93 oligodendrocytes after KA treatment, and increased expression was prevented by an antioxidant or free radical scavenger in vitro. This suggests that ACAT1 expression may be induced by oxidative stress. Together, our results show elevated ACAT1 expression and increased cholesteryl esters after KA excitotoxicity. Further studies are necessary to determine a possible role of ACAT1 in acute and chronic neurodegenerative diseases.
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Affiliation(s)
- J-H Kim
- Department of Anatomy, National University of Singapore, Singapore 119260
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Choi HJ, Kang KS, Fukui M, Zhu BT. Critical role of the JNK-p53-GADD45α apoptotic cascade in mediating oxidative cytotoxicity in hippocampal neurons. Br J Pharmacol 2011; 162:175-92. [PMID: 20955365 DOI: 10.1111/j.1476-5381.2010.01041.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Glutamate-induced oxidative stress plays a critical role in the induction of neuronal cell death in a number of disease states. We sought to determine the role of the c-Jun NH(2) -terminal kinase (JNK)-p53-growth arrest and DNA damage-inducible gene (GADD) 45α apoptotic cascade in mediating glutamate-induced oxidative cytotoxicity in hippocampal neuronal cells. EXPERIMENTAL APPROACH HT22 cells, a mouse hippocampal neuronal cell line, were treated with glutamate to induce oxidative stress in vitro. Kainic acid-induced oxidative damage to the hippocampus in rats was used as an in vivo model. The signalling molecules along the JNK-p53-GADD45α cascade were probed with various means to determine their contributions to oxidative neurotoxicity. KEY RESULTS Treatment of HT22 cells with glutamate increased the mRNA and protein levels of GADD45α, and these increases were suppressed by p53 knock-down. Knock-down of either p53 or GADD45α also prevented glutamate-induced cell death. Glutamate-induced p53 activation was preceded by accumulation of reactive oxygen species, and co-treatment with N-acetyl-cysteine prevented glutamate-induced p53 activation and GADD45α expression. Knock-down of MKK4 or JNK, or the presence of SP600125 (a JNK inhibitor), each inhibited glutamate-induced p53 activation and GADD45α expression. In addition, we also confirmed the involvement of GADD45α in mediating kainic acid-induced hippocampal oxidative neurotoxicity in vivo. CONCLUSIONS AND IMPLICATIONS Activation of the JNK-p53-GADD45α cascade played a critical role in mediating oxidative cytotoxicity in hippocampal neurons. Pharmacological inhibition of this signalling cascade may provide an effective strategy for neuroprotection.
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Affiliation(s)
- Hye Joung Choi
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Abstract
OBJECTIVE Cholesterol 24-hydroxylase catalyzes the conversion of cholesterol to 24-hydroxycholesterol, which is a major pathway for cholesterol elimination from the brain, since 24-hydroxycholesterol can readily cross the blood brain barrier. The present study aimed to elucidate the distribution of cholesterol 24-hydroxylase in the monkey brain. METHODS The distribution of cholesterol 24-hydroxylase in the monkey brain was examined using Western blot and immunohistochemistry methods, and was observed under light microscopy and electron microscopy. RESULTS High levels of cholesterol 24-hydroxylase were observed in projection neurons and neuropil in structures derived from telencephalon, including the cerebral neocortex, hippocampus, amygdala, nucleus basalis of Meynert, and striatum. Electron microscopy revealed that the enzyme was localized in the axon terminals. One the other hand, cholesterol 24-hydroxylase was expressed at a lower level in the thalamus, globus pallidus and brainstem. CONCLUSION The high level of cholesterol 24-hydroxylase in the telencephalon possibly reflects a high rate of cholesterol turnover in this part of brain.
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Kang KS, Wen Y, Yamabe N, Fukui M, Bishop SC, Zhu BT. Dual beneficial effects of (-)-epigallocatechin-3-gallate on levodopa methylation and hippocampal neurodegeneration: in vitro and in vivo studies. PLoS One 2010; 5:e11951. [PMID: 20700524 PMCID: PMC2916818 DOI: 10.1371/journal.pone.0011951] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 07/08/2010] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND A combination of levodopa (L-DOPA) and carbidopa is the most commonly-used treatment for symptom management in Parkinson's disease. Studies have shown that concomitant use of a COMT inhibitor is highly beneficial in controlling the wearing-off phenomenon by improving L-DOPA bioavailability as well as brain entry. The present study sought to determine whether (-)-epigallocatechin-3-gallate (EGCG), a common tea polyphenol, can serve as a naturally-occurring COMT inhibitor that also possesses neuroprotective actions. METHODOLOGY/PRINCIPAL FINDINGS Using both in vitro and in vivo models, we investigated the modulating effects of EGCG on L-DOPA methylation as well as on chemically induced oxidative neuronal damage and degeneration. EGCG strongly inhibited human liver COMT-mediated O-methylation of L-DOPA in a concentration-dependent manner in vitro, with an average IC50 of 0.36 microM. Oral administration of EGCG moderately lowered the accumulation of 3-O-methyldopa in the plasma and striatum of rats treated with L-DOPA+carbidopa. In addition, EGCG also reduced glutamate-induced oxidative cytotoxicity in cultured HT22 mouse hippocampal neuronal cells through inactivation of the nuclear factor kappaB-signaling pathway. Under in vivo conditions, administration of EGCG exerted a strong protective effect against kainic acid-induced oxidative neuronal death in the hippocampus of rats. CONCLUSIONS/SIGNIFICANCE These observations suggest that oral administration of EGCG may have significant beneficial effects in Parkinson's patients treated with L-DOPA and carbidopa by exerting a modest inhibition of L-DOPA methylation plus a strong neuroprotection against oxidative damage and degeneration.
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Affiliation(s)
- Ki Sung Kang
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Yujing Wen
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Noriko Yamabe
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Masayuki Fukui
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Stephanie C. Bishop
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Bao Ting Zhu
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
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Smiljanic K, Lavrnja I, Mladenovic Djordjevic A, Ruzdijic S, Stojiljkovic M, Pekovic S, Kanazir S. Brain injury induces cholesterol 24-hydroxylase (Cyp46) expression in glial cells in a time-dependent manner. Histochem Cell Biol 2010; 134:159-69. [PMID: 20559650 DOI: 10.1007/s00418-010-0718-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2010] [Indexed: 12/14/2022]
Abstract
Maintaining the cholesterol homeostasis is essential for normal CNS functioning. The enzyme responsible for elimination of cholesterol excess from the brain is cholesterol 24-hydroxylase (Cyp46). Since cholesterol homeostasis is disrupted following brain injury, in this study we examined the effect of right sensorimotor cortex suction ablation on cellular and temporal pattern of Cyp46 expression in the rat brain. Increased expression of Cyp46 at the lesion site at all post injury time points (2, 7, 14, 28 and 45 days post injury, dpi) was detected. Double immunofluorescence staining revealed colocalization of Cyp46 expression with different types of glial cells in time-dependent manner. In ED1(+) microglia/macrophages Cyp46 expression was most prominent at 2 and 7 dpi, whereas Cyp46 immunoreactivity persisted in reactive astrocytes throughout all time points post-injury. However, during the first 2 weeks Cyp46 expression was enhanced in both GFAP(+) and Vim(+) astrocytes, while at 28 and 45 dpi its expression was mostly associated with GFAP(+) cells. Pattern of neuronal Cyp46 expression remained unchanged after the lesion, i.e. Cyp46 immunostaining was detected in dendrites and cell body, but not in axons. The results of this study clearly demonstrate that in pathological conditions, like brain injury, Cyp46 displayed atypical expression, being expressed not only in neuronal cells, but also in microglia and astrocytes. Therefore, injury-induced expression of Cyp46 in microglial and astroglial cells may be involved in the post-injury removal of damaged cell membranes contributing to re-establishment of the brain cholesterol homeostasis.
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Affiliation(s)
- Kosara Smiljanic
- Department of Neurobiology, Institute for Biological Research Sinisa Stankovic, University of Belgrade, Belgrade, Serbia
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31
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Ma MT, Zhang J, Farooqui AA, Chen P, Ong WY. Effects of cholesterol oxidation products on exocytosis. Neurosci Lett 2010; 476:36-41. [DOI: 10.1016/j.neulet.2010.03.078] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 03/31/2010] [Accepted: 03/31/2010] [Indexed: 12/13/2022]
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Ong WY, Kim JH, He X, Chen P, Farooqui AA, Jenner AM. Changes in brain cholesterol metabolome after excitotoxicity. Mol Neurobiol 2010; 41:299-313. [PMID: 20140539 DOI: 10.1007/s12035-010-8099-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 01/07/2010] [Indexed: 12/15/2022]
Abstract
Excitotoxicity due to excess stimulation of glutamate receptors in neurons is accompanied by increased Ca(2+) influx, stimulation of Ca(2+)-dependent enzymes, ATP depletion, increase in lipid peroxidation products, and loss of glutathione. These changes resemble neurochemical alterations in acute neuronal injury (stroke, spinal cord injury, and traumatic brain injury) and chronic neurodegenerative diseases such as Alzheimer's disease. Intracerebroventricular injection of the potent glutamate analog kainate in rats results in increased cholesterol concentration in the hippocampus at short to medium time intervals, i.e., 3 days-1 week post-injection, as detected by gas chromatography-mass spectrometry in the lesioned hippocampus. This is accompanied by an early increase in levels of cholesterol biosynthetic precursors and increases in both enzymatically derived oxysterols such as 24-hydroxycholesterol and cholesterol oxidation products (COPs) generated by reactive oxygen species, including cholesterol epoxides and 7-ketocholesterol. In contrast to COPs, no change in concentration of the neurosteroid pregnenolone was found after KA injury. Cholesterol and COPs significantly increase exocytosis in cultured PC12 cells and neurons, and both oxysterols and COPs are able to induce cytotoxic and apoptotic injuries in different cell types, including neurons. Together, the findings suggest that increased cholesterol and COPs after KA excitotoxicity could themselves lead to disturbed neuronal ion homeostasis, increased neurotransmitter release, and propagation of excitotoxicity.
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Affiliation(s)
- Wei-Yi Ong
- Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore.
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24S-hydroxycholesterol effects on lipid metabolism genes are modeled in traumatic brain injury. Brain Res 2010; 1319:1-12. [PMID: 20053345 DOI: 10.1016/j.brainres.2009.12.080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 12/16/2009] [Accepted: 12/23/2009] [Indexed: 12/22/2022]
Abstract
Membrane damage during traumatic brain injury (TBI) alters the brain homeostasis of cholesterol and other lipids. Cholesterol 24S-hydroxylase (Cyp46) is a cholesterol metabolic enzyme that is increased after TBI. Here, we systematically examined the effects of the enzymatic product of Cyp46, 24S-hydroxycholesterol, on the cholesterol regulatory genes, SREBP-1 and 2, their posttranslational regulation, and their effects on gene transcription. 24S-hydroxycholesterol increased levels of SREBP-1 mRNA and full-length protein but did not change levels of cleaved SREBP-1, consistent with the role of 24-hydroxycholesterol as an LXR agonist. In contrast, 24S-hydroxycholesterol decreased levels of LXR-independent SREBP-2 mRNA, full-length protein, and SREBP-2 active cleavage product. We examined the downstream effects of changes to these lipid regulatory factors by studying cholesterol and fatty acid synthesis genes. In neuroblastoma cells, 24S-hydroxycholesterol decreased mRNA levels of the cholesterol synthesis genes HMG CoA reductase, squalene synthase, and FPP synthase but did not alter levels of the mRNA of fatty acid synthesis genes acetyl CoA carboxylase or fatty acid synthase. After TBI, as after 24S-hydroxycholesterol treatment in vitro, SREBP-1 mRNA levels were increased while SREBP-2 mRNA levels were decreased. Also similar to the in vitro results with 24S-hydroxycholesterol, HMG CoA reductase and squalene synthase mRNA levels were significantly decreased. Fatty acid synthase mRNA levels were not altered but acetyl CoA carboxylase mRNA levels were significantly decreased. Thus, changes to transcription of cholesterol synthesis genes after TBI were consistent with increases in Cyp46 activity, but changes to fatty acid synthesis genes must be regulated by other mechanisms.
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Abrahamson EE, Ikonomovic MD, Dixon CE, DeKosky ST. Simvastatin therapy prevents brain trauma-induced increases in beta-amyloid peptide levels. Ann Neurol 2009; 66:407-14. [PMID: 19798641 DOI: 10.1002/ana.21731] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Elevations in beta-amyloid peptide (A beta) levels after traumatic brain injury (TBI) may confer risk for developing Alzheimer's disease in head trauma patients. We investigated the effects of simvastatin, a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, on hippocampal A beta burden in a clinically relevant head injury/intervention model using mice expressing human A beta. Simvastatin therapy blunted TBI-induced increases in A beta, reduced hippocampal tissue damage and microglial activation, and improved behavioral outcome. The ability of statins to reduce post-injury A beta load and ameliorate pathological sequelae of brain injury makes them potentially effective in reducing the risk of developing Alzheimer's disease in TBI patients.
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Affiliation(s)
- Eric E Abrahamson
- Department of Neurology, Brain Trauma Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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35
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Kim JH, Jittiwat J, Ong WY, Farooqui AA, Jenner AM. Changes in cholesterol biosynthetic and transport pathways after excitotoxicity. J Neurochem 2009; 112:34-41. [PMID: 19860851 DOI: 10.1111/j.1471-4159.2009.06449.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present study was carried out to elucidate changes in the gene expression and activity of cholesterol biosynthetic enzymes and transporters in the rat hippocampus after kainate excitotoxicity. Significantly increased cholesterol level was detected in the degenerating hippocampus, reaching double normal levels at 1 week after kainate injury. RT-PCR analyses of hippocampal homogenates showed significantly decreased mRNA expression of the transcription factor controlling cholesterol biosynthesis SREBP-2, and the rate-controlling enzyme HMG-CoA (3-hydroxy-3-methyl-glutaryl-CoA) reductase at all time points after kainate injection; and decreased lanosterol synthase and CYP51 at 1 and 2 weeks post-kainate injection respectively. GC-MS analyses showed a significant increase in cholesterol biosynthetic precursors lanosterol, desmosterol and 7-dehydrocholesterol at 1 day after kainate injection presumably reflecting biosysnthesis in injured neurons, and significant decreases in precursors at 1 and 2 weeks post-kainate injection, at time of gliosis in the degenerating hippocampus. Levels of cholesterol autooxidation including 7 ketocholesterol and cholesterol epoxides were elevated in the kainate lesioned hippocampus. Furthermore, loss of expression of the cholesterol transporter, ABCA1 was detected in neurons, but increased expression in astrocytes was detected after kainate lesions. The results suggest that increased cholesterol biosynthesis and loss of ABCA1 expression in injured neurons might result in increase in cholesterol in the degenerating hippocampus. The increased cholesterol might predispose to increased formation of cholesterol oxidation products which have been shown to be toxic to neurons.
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Affiliation(s)
- Ji-Hyun Kim
- Department of Anatomy, National University of Singapore, Singapore
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36
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Zhao S, Liao W, Xu N, Xu H, Yu C, Liu X, Li C. Polar metabolite of cholesterol induces rat cognitive dysfunctions. Neuroscience 2009; 164:398-403. [PMID: 19699274 DOI: 10.1016/j.neuroscience.2009.08.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/08/2009] [Accepted: 08/12/2009] [Indexed: 12/31/2022]
Abstract
24-hydroxycholesterol, a major polar metabolite of brain cholesterol, has neurotoxic effects. However, little is known about the effects of this polar metabolite on the CNS. In the present study, the effects of 24-hydroxycholesterol on behavior changes were investigated. Rats were divided into three groups: (i) a control group; (ii) a sham group: 0.5 ml PBS was infused into the cerebral ventricle; (iii) a model group: 0.5 ml 24-hydroxycholesterol (10 microM) was infused into the cerebral ventricle. 24-hydroxycholesterol can obviously impair rats' acquisition and probe trial in the Morris Water Maze task. Compared with rats in the sham group, rats in the model group had longer escape latency time and traveled more distance, and performed worse in the probe trial task manifested by spending less time in the annulus and training quadrant, which probably was attributed to the neuronal degeneration in hippocampal CA1 area induced by 24-hydroxycholesterol as examined by histological assay and apoptotic assay. Our results revealed that the polar metabolites, such as 24-hydroxycholesterol, exert neurotoxic effects and exacerbate the neuron injury with their abnormal accumulation. These findings suggest that measures taken promptly to eliminate or inhibit the accumulation of polar metabolites should be a potential strategy to prevent neurological dysfunctions and promote the recovery of functional deficits after neurotoxic insult.
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Affiliation(s)
- S Zhao
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China
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37
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Ong WY, Jenner AM, Pan N, Ong CN, Halliwell B. Elevated oxidative stress, iron accumulation around microvessels and increased 4-hydroxynonenal immunostaining in zone 1 of the liver acinus in hypercholesterolemic rabbits. Free Radic Res 2009; 43:241-9. [DOI: 10.1080/10715760802691455] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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38
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Saldanha CJ, Duncan KA, Walters BJ. Neuroprotective actions of brain aromatase. Front Neuroendocrinol 2009; 30:106-18. [PMID: 19450619 PMCID: PMC2700852 DOI: 10.1016/j.yfrne.2009.04.016] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 04/02/2009] [Accepted: 04/14/2009] [Indexed: 12/16/2022]
Abstract
The steroidal regulation of vertebrate neuroanatomy and neurophysiology includes a seemingly unending list of brain areas, cellular structures and behaviors modulated by these hormones. Estrogens, in particular have emerged as potent neuromodulators, exerting a range of effects including neuroprotection and perhaps neural repair. In songbirds and mammals, the brain itself appears to be the site of injury-induced estrogen synthesis via the rapid transcription and translation of aromatase (estrogen synthase) in astroglia. This induction seems to occur regardless of the nature and location of primary brain damage. The induced expression of aromatase apparently elevates local estrogen levels enough to interfere with apoptotic pathways, thereby decreasing secondary degeneration and ultimately lessening the extent of damage. There is even evidence suggesting that aromatization may affect injury-induced cytogenesis. Thus, aromatization in the brain appears to confer neuroprotection by an array of mechanisms that involve the deceleration and acceleration of degeneration and repair, respectively. We are only beginning to understand the factors responsible for the injury-induced transcription of aromatase in astroglia. In contrast, much of the manner in which local and circulating estrogens may achieve their neuroprotective effects has been elucidated. However, gaps in our knowledge include issues about the cell-specific regulation of aromatase expression, steroidal influences of aromatization distinct from estrogen formation, and questions about the role of constitutive aromatase in neuroprotection. Here we describe the considerable consensus and some interesting differences in knowledge gained from studies conducted on diverse animal models, experimental paradigms and preparations towards understanding the neuroprotective actions of brain aromatase.
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Affiliation(s)
- Colin J Saldanha
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, United States.
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He X, Jittiwat J, Kim JH, Jenner AM, Farooqui AA, Patel SC, Ong WY. Apolipoprotein D modulates F2-isoprostane and 7-ketocholesterol formation and has a neuroprotective effect on organotypic hippocampal cultures after kainate-induced excitotoxic injury. Neurosci Lett 2009; 455:183-6. [PMID: 19429117 PMCID: PMC7117013 DOI: 10.1016/j.neulet.2009.03.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 02/24/2009] [Accepted: 03/09/2009] [Indexed: 11/26/2022]
Abstract
Apolipoprotein D (apoD), a member of the lipocalin family of transporter proteins binds a number of small lipophilic molecules including arachidonic acid and cholesterol. Recent studies showed a protective function of mammalian apoD as well as its insect and plant homologs against oxidative stress. In this study we investigated the effect of direct addition of exogenous human apoD protein purified from breast cystic fluid to rat hippocampal slice cultures after excitotoxic injury induced by the glutamate analog kainate. ApoD at a concentration of 10 microg/ml partially prevented loss of MAP2 immunostaining and LDH release from injured hippocampal neurons after kainate injury. ApoD also attenuated the increase in oxidative products of arachidonic acid and cholesterol, F(2)-isoprostanes and 7-ketocholesterol, respectively, after kainate treatment. In view of the molecular structure of apoD which consists of an eight stranded beta barrel that forms a binding pocket for a number of small hydrophobic molecules, we propose that apoD promotes its neuroprotective effects by binding to arachidonic acid and cholesterol thus preventing their oxidation to neurotoxic products such as 4-hydroxynonenal (4-HNE) and 7-ketocholesterol.
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Affiliation(s)
- Xin He
- Department of Anatomy, Beijing University of Chinese Medicine, Beijing 100029, China
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40
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Kim JH, Ong WY. Localization of the transcription factor, sterol regulatory element binding protein-2 (SREBP-2) in the normal rat brain and changes after kainate-induced excitotoxic injury. J Chem Neuroanat 2009; 37:71-7. [DOI: 10.1016/j.jchemneu.2008.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 12/05/2008] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
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41
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Cartagena CM, Ahmed F, Burns MP, Pajoohesh-Ganji A, Pak DT, Faden AI, Rebeck GW. Cortical injury increases cholesterol 24S hydroxylase (Cyp46) levels in the rat brain. J Neurotrauma 2008; 25:1087-98. [PMID: 18729719 DOI: 10.1089/neu.2007.0444] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In traumatic brain injury (TBI), cellular loss from initial impact as well as secondary neurodegeneration leads to increased cholesterol and lipid debris at the site of injury. Cholesterol accumulation in the periphery can trigger inflammatory mechanisms while cholesterol clearance may be anti-inflammatory. Here we investigated whether TBI altered the regulation of cholesterol 24S-hydroxylase (Cyp46), an enzyme that converts cholesterol to the more hydrophilic 24S-hydroxycholesterol. We examined by Western blot and immunohistochemistry changes in Cyp46 expression following fluid percussion injury. Under normal conditions, most Cyp46 was present in neurons, with very little measurable in glia. Cyp46 levels were significantly increased at 7 days post-injury, and cell type specific analysis at 3 days post-injury showed a significant increase in levels of Cyp46 (84%) in microglia. Since 24-hydroxycholesterol induces activation of genes through the liver X receptor (LXR), we examined protein levels of ATP-binding cassette transporter A1 and apolipoprotein E, two LXR regulated cholesterol homeostasis proteins. Apolipoprotein E and ATP-binding cassette transporter A1 were increased at 7 days post-injury, indicating that increased LXR activity coincided with increased Cyp46 levels. We found that activation of primary rat microglia by LPS in vitro caused increased Cyp46 levels. These data suggest that increased microglial Cyp46 activity is part of a system for removal of damaged cell membranes post-injury, by conversion of cholesterol to 24-hydroxycholesterol and by activation of LXR-regulated gene transcription.
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Affiliation(s)
- Casandra M Cartagena
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20057, USA
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42
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Changes in cytochrome P450 side chain cleavage expression in the rat hippocampus after kainate injury. Exp Brain Res 2007; 186:143-9. [DOI: 10.1007/s00221-007-1209-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 11/06/2007] [Indexed: 10/22/2022]
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43
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Comparison of biochemical effects of statins and fish oil in brain: the battle of the titans. ACTA ACUST UNITED AC 2007; 56:443-71. [PMID: 17959252 DOI: 10.1016/j.brainresrev.2007.09.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 09/16/2007] [Accepted: 09/17/2007] [Indexed: 11/20/2022]
Abstract
Neural membranes are composed of glycerophospholipids, sphingolipids, cholesterol and proteins. The distribution of these lipids within the neural membrane is not random but organized. Neural membranes contain lipid rafts or microdomains that are enriched in sphingolipids and cholesterol. These rafts act as platforms for the generation of glycerophospholipid-, sphingolipid-, and cholesterol-derived second messengers, lipid mediators that are necessary for normal cellular function. Glycerophospholipid-derived lipid mediators include eicosanoids, docosanoids, lipoxins, and platelet-activating factor. Sphingolipid-derived lipid mediators include ceramides, ceramide 1-phosphates, and sphingosine 1-phosphate. Cholesterol-derived lipid mediators include 24-hydroxycholesterol, 25-hydroxycholesterol, and 7-ketocholesterol. Abnormal signal transduction processes and enhanced production of lipid mediators cause oxidative stress and inflammation. These processes are closely associated with the pathogenesis of acute neural trauma (stroke, spinal cord injury, and head injury) and neurodegenerative diseases such as Alzheimer disease. Statins, the HMG-CoA reductase inhibitors, are effective lipid lowering agents that significantly reduce risk for cardiovascular and cerebrovascular diseases. Beneficial effects of statins in neurological diseases are due to their anti-excitotoxic, antioxidant, and anti-inflammatory properties. Fish oil omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, have similar anti-excitotoxic, antioxidant and anti-inflammatory effects in brain tissue. Thus the lipid mediators, resolvins, protectins, and neuroprotectins, derived from eicosapentaenoic acid and docosahexaenoic acid retard neuroinflammation, oxidative stress, and apoptotic cell death in brain tissue. Like statins, ingredients of fish oil inhibit generation of beta-amyloid and provide protection from oxidative stress and inflammatory processes. Collective evidence suggests that antioxidant, anti-inflammatory, and anti-apoptotic properties of statins and fish oil contribute to the clinical efficacy of treating neurological disorders with statins and fish oil. We speculate that there is an overlap between neurochemical events associated with neural cell injury in stroke and neurodegenerative diseases. This commentary compares the neurochemical effects of statins with those of fish oil.
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