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Lazarova M, Tancheva L, Alexandrova A, Tsvetanova E, Georgieva A, Stefanova M, Tsekova D, Vezenkov L, Kalfin R, Uzunova D, Petkova-Kirova P. Effects of New Galantamine Derivatives in a Scopolamine Model of Dementia in Mice. J Alzheimers Dis 2021; 84:671-690. [PMID: 34569967 DOI: 10.3233/jad-215165] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease. In the present study, using behavioral and biochemical methods, four newly synthesized galantamine derivatives, Gal 34, Gal 43, Gal 44, and Gal 46, were evaluated for a beneficial effect in a scopolamine model of dementia in mice. They were designed to have all the advantages of galantamine and additionally to inhibit β-secretase and exert favorable effects on plasma lipids. Behavioral tests included step-through inhibitory avoidance, T-maze, and the hole-board test, whereas biochemical evaluations involved assessment of acetylcholinesterase activity, brain monoamines levels, lipid peroxidation, catalase, glutathione peroxidase, and superoxide dismutase activities along with measurement of total glutathione. Results show that Gal 43, Gal 44, and, in particular, Gal 46 are especially effective in improving both short- and long-term memory and in the case of Gal 46 having a significant effect on exploratory activity as well. Although Gal 34 did not show behavioral effects as convincing as those of the other three galantamine derivatives, it demonstrated persuasive antioxidant and restorative capacities, making all four galantamine derivatives promising AD treatment agents and prompting further research, especially that in many of our studies they performed better than galantamine.
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Affiliation(s)
- Maria Lazarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Lyubka Tancheva
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Albena Alexandrova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.,National Sports Academy, Sofia, Bulgaria
| | - Elina Tsvetanova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Almira Georgieva
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | | | - Daniela Tsekova
- Department of Organic Chemistry, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
| | - Lyubomir Vezenkov
- Department of Organic Chemistry, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
| | - Reni Kalfin
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Diamara Uzunova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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Abstract
Background: Alzheimer's disease is known as one of the fastest growing lethal diseases worldwide where we have limited and undesired ways for regulating its pathological progress. Now-a-days, nutritional compounds have been using to treat several brain disorders and one of them; vitamins were strongly reported to combat cognition and memory deterioration in neurodegenerative diseases including Alzheimer's disease. Objective: Here, the author tried to find the precise physiological roles, status, and worth of vitamins in the brain and how exactly these nutrients modulate progression of Alzheimer's disease. Results & Discussion: After a comprehensive and systematic literature review, the author reports that vitamins have various targets in Alzheimer's disease pathogenesis by which they act to avert the neuronal dysfunction in the disease. Several Alzheimer's disease-associated neurological deficits have reported regulating by vitamin intake but the beneficial effects identified mostly in combinatorial and long-term studies. Conclusion: In this way, the author suggests that it might be better to test vitamins with other components over single vitamin approach for a compatible and synergistic effect as well as using a combination of vitamin with other compounds can target multiple pathways. This strategy may help in deteriorating memory dysfunction and cognition impairment in Alzheimer's disease pathophysiology.Abbreviations: APOE: apolipoprotein E; APP: amyloid precursor protein; ATP: adenosine triphosphate; Aβ- β-amyloid; cGMP: cyclic guanine monophosphate; CNS: central nervous system; DNA: deoxyribonucleic acid; IU: international units; RA: retinoic acid; RAR: retinoic acid receptor; RNA: ribonucleic acid; ROS: reactive oxygen species; tHcy: total homocysteine; α: alpha; β: beta; γ: gama; ε: epsilon; g: gram; µ: micron; mg: milligram; ⬆: increased,⬇: decreased.
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Affiliation(s)
- Jahangir Alam
- Department of Pharmacology, School of Pharmaceutical Sciences, Shoolini University, Solan, India.,Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Bareilly, India
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Turunc Bayrakdar E, Armagan G, Uyanikgil Y, Kanit L, Koylu E, Yalcin A. Ex vivoprotective effects of nicotinamide and 3-aminobenzamide on rat synaptosomes treated with Aβ(1-42). Cell Biochem Funct 2014; 32:557-64. [DOI: 10.1002/cbf.3049] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/24/2014] [Accepted: 07/17/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Ezgi Turunc Bayrakdar
- Department of Biochemistry, Faculty of Pharmacy; Ege University; Bornova Izmir Turkey
| | - Guliz Armagan
- Department of Biochemistry, Faculty of Pharmacy; Ege University; Bornova Izmir Turkey
| | - Yigit Uyanikgil
- Department of Histology and Embryology, Faculty of Medicine; Ege University; Bornova Izmir Turkey
| | - Lutfiye Kanit
- Center for Brain Research, Faculty of Medicine; Ege University; Bornova Izmir Turkey
- Department of Neurosciences, Institute of Health Sciences; Ege University; Bornova Izmir Turkey
- Department of Physiology, Faculty of Medicine; Ege University; Bornova Izmir Turkey
| | - Ersin Koylu
- Center for Brain Research, Faculty of Medicine; Ege University; Bornova Izmir Turkey
- Department of Neurosciences, Institute of Health Sciences; Ege University; Bornova Izmir Turkey
- Department of Physiology, Faculty of Medicine; Ege University; Bornova Izmir Turkey
| | - Ayfer Yalcin
- Department of Biochemistry, Faculty of Pharmacy; Ege University; Bornova Izmir Turkey
- Center for Brain Research, Faculty of Medicine; Ege University; Bornova Izmir Turkey
- Department of Neurosciences, Institute of Health Sciences; Ege University; Bornova Izmir Turkey
- Department of Biochemistry; Faculty of Pharmacy, Biruni University; Topkapi Istanbul Turkey
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4
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Turunc Bayrakdar E, Uyanikgil Y, Kanit L, Koylu E, Yalcin A. Nicotinamide treatment reduces the levels of oxidative stress, apoptosis, and PARP-1 activity in Aβ(1-42)-induced rat model of Alzheimer's disease. Free Radic Res 2013; 48:146-58. [PMID: 24151909 DOI: 10.3109/10715762.2013.857018] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The underlying mechanisms of Alzheimer's Disease (AD) are still unclear. It is suggested that poly(ADP-ribose) polymerase-1 (PARP-1) overactivation can cause neuroinflammation and cell death. In this study we searched the effects of nicotinamide (NA), endogenous PARP-1 inhibitor, on oxidative stress, apoptosis, and the regulation of PARP-1 and nuclear factor kappa B (NF-κB) in amyloid beta peptide (1-42) (Aβ(1-42))-induced neurodegeneration. Sprague-Dawley rats were divided into four groups as control, Aβ(1-42), Aβ(1-42) + NA(100 and 500 mg/kg). All groups were stereotaxically injected bilaterally into the hippocampus with Aβ(1-42) or saline. After surgery NA administrations were made intraperitoneally (ip) for 7 days. In order to investigate the effects of Aβ(1-42) and NA, protein carbonyls, lipid peroxidation, reactive oxygen species (ROS) production, glutathione (GSH) levels, activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), mitochondrial function, mRNA and protein levels of PARP-1, NF-κB, p53, Bax, and Bcl-2 were measured in specific brain regions such as cortex and hippocampus. Aβ(1-42) treatment only increased the oxidative stress parameters and caused decline in antioxidant enzyme activities, mitochondrial function, and GSH levels. Also, overexpression of PARP-1, NF-κB, p53, Bax, and the decreased levels of Bcl-2 were observed in Aβ(1-42)-treated group. NA treatments against Aβ(1-42)-upregulated Bcl-2 and downregulated PARP-1, NF-κB, p53, and Bax levels. NA treatments also decreased the oxidative stress parameters and elevated antioxidant enzyme activities, GSH levels, and mitochondrial function against Aβ(1-42) treatment. These data suggest that NA may have a therapeutic potential in neurodegenerative processes due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activity.
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Affiliation(s)
- E Turunc Bayrakdar
- Department of Biochemistry, Faculty of Pharmacy, Ege University , Bornova, Izmir , Turkey
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Chauhan NB, Gatto R. Synergistic benefits of erythropoietin and simvastatin after traumatic brain injury. Brain Res 2010; 1360:177-92. [PMID: 20833152 DOI: 10.1016/j.brainres.2010.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 08/30/2010] [Accepted: 09/02/2010] [Indexed: 10/19/2022]
Abstract
Simvastatin and recombinant human erythropoietin (rhEpo) are implicated as potential therapeutic candidates for traumatic brain injury (TBI). Prominent effects of simvastatin include its anti-inflammatory, neurotrophic and neuroregenerative actions studied in various models of neuronal injury. On the other hand, rhEpo has been shown to promote cell survival mechanisms by producing anti-apoptotic and cell proliferative actions. Beneficial effects of rhEpo and statin monotherapies have been well studied. However, there are no reports showing combined use of rhEpo and statins after TBI. This investigation examined if combined efficacy of cell proliferative ability of rhEpo along with the neuroregenerative ability of simvastatin will render maximum recovery in a controlled cortical impact (CCI) mouse model of TBI. Results showed that compared to baseline TBI, rhEpo was more effective than simvastatin in promoting cell proliferation while simvastatin was more effective than rhEpo in restoring axonal damage following TBI. Combined treatment with simvastatin and rhEpo maximally restored axonal integrity while simultaneously inducing greater proliferation of newly formed cells resulting in better functional recovery after TBI than either alone. This is the first study showing the efficacy of erythropoietin-simvastatin combinational therapeutic approach in achieving greater structural and cognitive recovery after TBI.
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Affiliation(s)
- Neelima B Chauhan
- Jesse Brown VA Medical Center, University of Illinois, Chicago, USA.
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Corneveaux JJ, Myers AJ, Allen AN, Pruzin JJ, Ramirez M, Engel A, Nalls MA, Chen K, Lee W, Chewning K, Villa SE, Meechoovet HB, Gerber JD, Frost D, Benson HL, O'Reilly S, Chibnik LB, Shulman JM, Singleton AB, Craig DW, Van Keuren-Jensen KR, Dunckley T, Bennett DA, De Jager PL, Heward C, Hardy J, Reiman EM, Huentelman MJ. Association of CR1, CLU and PICALM with Alzheimer's disease in a cohort of clinically characterized and neuropathologically verified individuals. Hum Mol Genet 2010; 19:3295-301. [PMID: 20534741 DOI: 10.1093/hmg/ddq221] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, we assess 34 of the most replicated genetic associations for Alzheimer's disease (AD) using data generated on Affymetrix SNP 6.0 arrays and imputed at over 5.7 million markers from a unique cohort of over 1600 neuropathologically defined AD cases and controls (1019 cases and 591 controls). Testing the top genes from the AlzGene meta-analysis, we confirm the well-known association with APOE single nucleotide polymorphisms (SNPs), the CLU, PICALM and CR1 SNPs recently implicated in unusually large data sets, and previously implicated CST3 and ACE SNPs. In the cases of CLU, PICALM and CR1, as well as in APOE, the odds ratios we find are slightly larger than those previously reported in clinical samples, consistent with what we believe to be more accurate classification of disease in the clinically characterized and neuropathologically confirmed AD cases and controls.
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Affiliation(s)
- Jason J Corneveaux
- Neurogenomics Division, The Translational Genomics Research Institute (Gen, 445 N Fifth Street, Phoenix, AZ 85004, USA
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7
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Harris JR, Milton NGN. Cholesterol in Alzheimer's disease and other amyloidogenic disorders. Subcell Biochem 2010; 51:47-75. [PMID: 20213540 DOI: 10.1007/978-90-481-8622-8_2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The complex association of cholesterol metabolism and Alzheimer's disease is presented in depth, including the possible benefits to be gained from cholesterol-lowering statin therapy. Then follows a survey of the role of neuronal membrane cholesterol in Abeta pore formation and Abeta fibrillogenesis, together with the link with membrane raft domains and gangliosides. The contribution of structural studies to Abeta fibrillogenesis, using TEM and AFM, is given some emphasis. The role of apolipoprotein E and its isoforms, in particular ApoE4, in cholesterol and Abeta binding is presented, in relation to genetic risk factors for Alzheimer's disease. Increasing evidence suggests that cholesterol oxidation products are of importance in generation of Alzheimer's disease, possibly induced by Abeta-produced hydrogen peroxide. The body of evidence for a link between cholesterol in atherosclerosis and Alzheimer's disease is increasing, along with an associated inflammatory response. The possible role of cholesterol in tau fibrillization, tauopathies and in some other non-Abeta amyloidogenic disorders is surveyed.
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Affiliation(s)
- J Robin Harris
- Institute of Zoology, University of Mainz, D-55099, Mainz, Germany.
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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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9
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Lemberger T, Parkitna JR, Chai M, Schütz G, Engblom D. CREB has a context-dependent role in activity-regulated transcription and maintains neuronal cholesterol homeostasis. FASEB J 2008; 22:2872-9. [PMID: 18424767 DOI: 10.1096/fj.08-107888] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Induction of specific gene expression patterns in response to activity confers functional plasticity to neurons. A principal role in the regulation of these processes has been ascribed to the cAMP responsive element binding protein (CREB). Using genome-wide expression profiling in mice lacking CREB in the forebrain, accompanied by deletion of the cAMP responsive element modulator gene (CREM), we here show that the role of these proteins in activity-induced gene expression is surprisingly selective and highly context dependent. Thus, only a very restricted subset of activity-induced genes (i.e., Gadd45b or Nr4a2) requires these proteins for their induction in the hippocampus after kainic acid administration, while they are required for most of the cocaine-induced expression changes in the striatum. Interestingly, in the absence of CREB, CREM is able to rescue activity-regulated transcription, which strengthens the notion of overlapping functions of the two proteins. In addition, we show that cholesterol metabolism is dysregulated in the brains of mutant mice, as reflected coordinated expression changes in genes involved in cholesterol synthesis and neuronal accumulation of cholesterol. These findings provide novel insights into the role of CREB and CREM in stimulus-dependent transcription and neuronal homeostasis.
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Cholesteryl ester transfer protein polymorphism D442G associated with a potential decreased risk for Alzheimer's disease as a modifier for APOE ε4 in Chinese. Brain Res 2008; 1187:52-7. [DOI: 10.1016/j.brainres.2007.10.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Revised: 10/07/2007] [Accepted: 10/16/2007] [Indexed: 11/21/2022]
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11
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Arias-Vásquez A, Isaacs A, Aulchenko YS, Hofman A, Oostra BA, Breteler M, van Duijn CM. The cholesteryl ester transfer protein (CETP) gene and the risk of Alzheimer's disease. Neurogenetics 2007; 8:189-93. [PMID: 17503098 DOI: 10.1007/s10048-007-0089-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 04/17/2007] [Indexed: 11/26/2022]
Abstract
Like the apolipoprotein E (APOE) gene, the most common genetic determinant for Alzheimer's disease (AD), the cholesteryl ester transfer protein (CETP) is involved in lipid metabolism. We studied the I405V polymorphism of the CETP gene in relation to AD. We genotyped 544 AD cases and 5,404 controls from the Rotterdam study, using a TaqMan allelic discrimination assay. Odds ratios (ORs) for AD were estimated using logistic regression analysis. CETP VV carriers showed significantly increased high-density lipoprotein levels compared to the IV and II carriers. In the overall analysis of AD, the risk of disease for the VV carriers of the CETP polymorphism was non-significantly increased compared to II carriers OR(VV) = 1.33, 95% confidence interval (CI) 0.96-1.90 p = 0.08). In those without the APOE*4 allele, the risk of AD for VV carriers was increased 1.67-fold (95% CI 1.11-2.52, p = 0.01). The difference in the relationship between CETP and AD between APOE*4 carriers and APOE*4 non-carriers was statistically significant (p for interaction = 0.04). Our results suggest that the VV genotype of the I405V polymorphism of the CETP gene increases the risk of AD in the absence of the APOE*4 allele, probably through a cholesterol metabolism pathway in the brain.
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Affiliation(s)
- Alejandro Arias-Vásquez
- Department of Epidemiology & Biostatistics, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
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12
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Hartmann T. Role of amyloid precursor protein, amyloid-beta and gamma-secretase in cholesterol maintenance. NEURODEGENER DIS 2006; 3:305-11. [PMID: 17047372 DOI: 10.1159/000095271] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Lipids play an important part as risk factors for Alzheimer's disease. This article summarizes the current understanding of the molecular mechanism by which amyloid-beta (Abeta) peptides regulate cholesterol and sphingomyelin metabolism, and how in return cholesterol and sphingomyelin regulate Abeta peptide production. An understanding of the physiological function of amyloid precursor protein processing and Abeta function is critical for the development of future therapeutic approaches, e.g. statin treatment.
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Affiliation(s)
- Tobias Hartmann
- Center for Molecular Biology, University of Heidelberg, Heidelberg, Germany.
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Korade Z, Mi Z, Portugal C, Schor NF. Expression and p75 neurotrophin receptor dependence of cholesterol synthetic enzymes in adult mouse brain. Neurobiol Aging 2006; 28:1522-31. [PMID: 16887237 DOI: 10.1016/j.neurobiolaging.2006.06.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 06/06/2006] [Accepted: 06/22/2006] [Indexed: 11/30/2022]
Abstract
Normal brain function depends critically on cholesterol. Although cholesterol is synthesized locally in the adult brain, the precise anatomical localization of cholesterogenic enzymes is not known. Here we show that 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoAred) and 7-dehydrocholesterol reductase (7dhcred), the first and last enzymes, respectively, in the cholesterol biosynthesis pathway, are co-expressed in neurons throughout adult murine brain. Co-localization is most prominent in cortical, hippocampal, and cholinergic neurons. Since adult hippocampal and cholinergic neurons express p75 neurotrophin receptors (p75NTR) we hypothesized that p75NTR regulates expression of cholesterogenic enzymes. Treatment of Neuro2a neuroblastoma cells or primary cerebellar cultures with siRNA downregulates p75NTR and decreases the expression level of HMG-CoAred and 7dhcred. Native neuroblastoma cell lines with differential expression of p75NTR differentially express 7dhcred; 7dhcred expression correlates with p75NTR expression. This suggests that, in p75NTR-expressing cells, p75NTR regulates cholesterol synthesis through regulation of HMG-CoAred and 7dhcred expression. The unexpected localization of cholesterogenic enzymes in adult neurons suggests that at least some adult neurons retain the ability to synthesize cholesterol.
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Affiliation(s)
- Zeljka Korade
- Pediatric Center for Neuroscience, Children's Hospital of Pittsburgh, Department of Pediatrics, University of Pittsburgh, PA, United States
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Pattar GR, Tackett L, Liu P, Elmendorf JS. Chromium picolinate positively influences the glucose transporter system via affecting cholesterol homeostasis in adipocytes cultured under hyperglycemic diabetic conditions. Mutat Res 2006; 610:93-100. [PMID: 16870493 PMCID: PMC2424232 DOI: 10.1016/j.mrgentox.2006.06.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2006] [Indexed: 11/26/2022]
Abstract
Since trivalent chromium (Cr(3+)) enhances glucose metabolism, interest in the use of Cr(3+)as a therapy for type 2 diabetes has grown in the mainstream medical community. Moreover, accumulating evidence suggests that Cr(3+) may also benefit cardiovascular disease (CVD) and atypical depression. We have found that cholesterol, a lipid implicated in both CVD and neurodegenerative disorders, also influences cellular glucose uptake. A recent study in our laboratory shows that exposure of 3T3-L1 adipocytes to chromium picolinate (CrPic, 10 nM) induces a loss of plasma membrane cholesterol. Concomitantly, accumulation of intracellularly sequestered glucose transporter GLUT4 at the plasma membrane was dependent on the CrPic-induced cholesterol loss. Since CrPic supplementation has the greatest benefit on glucose metabolism in hyperglycemic insulin-resistant individuals, we asked here if the CrPic effect on cells was glucose-dependent. We found that GLUT4 redistribution in cells treated with CrPic occurs only in cells cultured under high glucose (25 mM) conditions that resemble the diabetic-state, and not in cells cultured under non-diabetic (5.5 mM glucose) conditions. Examination of the effect of CrPic on proteins involved in cholesterol homeostasis revealed that the activity of sterol regulatory element-binding protein (SREBP), a membrane-bound transcription factor ultimately responsible for controlling cellular cholesterol balance, was upregulated by CrPic. In addition, ABCA1, a major player in mediating cholesterol efflux was decreased, consistent with SREBP transcriptional repression of the ABCA1 gene. Although the exact mechanism of Cr(3+)-induced cholesterol loss remains to be determined, these cellular responses highlight a novel and significant effect of chromium on cholesterol homeostasis. Furthermore, these findings provide an important clue to our understanding of how chromium supplementation might benefit hypercholesterolemia-associated disorders.
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Affiliation(s)
- Guruprasad R Pattar
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Center for Diabetes Research, Indianapolis, IN 46202, United States
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Lahiri DK, Ge YW, Maloney B, Wavrant-De Vrièze F, Hardy J. Characterization of two APP gene promoter polymorphisms that appear to influence risk of late-onset Alzheimer's disease. Neurobiol Aging 2004; 26:1329-41. [PMID: 16243604 DOI: 10.1016/j.neurobiolaging.2004.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 11/09/2004] [Accepted: 11/10/2004] [Indexed: 11/19/2022]
Abstract
Alzheimer's disease (AD) is characterized by formation of plaques of amyloid beta peptide (Abeta). Autosomally-inherited or "familial" AD had been demonstrated only in connection with coding sequence mutations. We characterized DNA-protein interaction and expression influence of two polymorphisms that occur in the promoter (C<-->T at -3829 and T<-->C at -1023, +1 transcription start site) of the Abeta precursor protein (APP) gene. We report distinct functional differences in reporter expression and in DNA-protein interaction for variant sequences in both -3829 and -1023 polymorphic regions. The -3829T variant has reduced DNA-protein interaction and reporter expression compared to -3829C, while -1023C has greater DNA-protein interaction and reporter expression than -1023T. Our predictions for likely transcription factors for loss of function (-3829T) are ADR1, MIG1, and PuF, and for gain of function (-1023C) are E12/E47, ITF-2, and RFX2. Characterization of the activity of a regulatory polymorphism of the APP gene points towards understanding mechanisms that likely underlie the majority of AD cases and may contribute to promoter-based drug design.
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Affiliation(s)
- Debomoy K Lahiri
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, 791 N. Union Drive, Indianapolis, IN 46202, USA.
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