1
|
Microglia and Cholesterol Handling: Implications for Alzheimer's Disease. Biomedicines 2022; 10:biomedicines10123105. [PMID: 36551857 PMCID: PMC9775660 DOI: 10.3390/biomedicines10123105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/04/2022] Open
Abstract
Cholesterol is essential for brain function and structure, however altered cholesterol metabolism and transport are hallmarks of multiple neurodegenerative conditions, including Alzheimer's disease (AD). The well-established link between apolipoprotein E (APOE) genotype and increased AD risk highlights the importance of cholesterol and lipid transport in AD etiology. Whereas more is known about the regulation and dysregulation of cholesterol metabolism and transport in neurons and astrocytes, less is known about how microglia, the immune cells of the brain, handle cholesterol, and the subsequent implications for the ability of microglia to perform their essential functions. Evidence is emerging that a high-cholesterol environment, particularly in the context of defects in the ability to transport cholesterol (e.g., expression of the high-risk APOE4 isoform), can lead to chronic activation, increased inflammatory signaling, and reduced phagocytic capacity, which have been associated with AD pathology. In this narrative review we describe how cholesterol regulates microglia phenotype and function, and discuss what is known about the effects of statins on microglia, as well as highlighting areas of future research to advance knowledge that can lead to the development of novel therapies for the prevention and treatment of AD.
Collapse
|
2
|
Shin JW, Lee JC. Roles of microglial membranes in Alzheimer's disease. CURRENT TOPICS IN MEMBRANES 2020; 86:301-314. [PMID: 33837697 PMCID: PMC8082413 DOI: 10.1016/bs.ctm.2020.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The majority of Alzheimer's disease (AD) risk genes are highly and selectively expressed by microglia in the brain. Several of these genes are related to lipid and cholesterol metabolism, lipid synthesis, lipid transport, endocytosis, exocytosis and phagocytosis. Therefore, studying the roles of cellular membrane biophysics in microglial function should improve our understanding of the AD pathology. In this chapter, we discuss how lipid rafts and membrane-cytoskeleton adhesion impact microglial-mediated oxidative stress and clearance of amyloid-β peptide (Aβ). We also discuss potential roles of lipid membrane-bound extracellular vesicles as carriers of pathological factors to promote inflammation and cytotoxicity.
Collapse
Affiliation(s)
- Jae-Won Shin
- Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States; Department of Pharmacology, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States
| | - James C Lee
- Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States.
| |
Collapse
|
3
|
Jeong W, Lee H, Cho S, Seo J. ApoE4-Induced Cholesterol Dysregulation and Its Brain Cell Type-Specific Implications in the Pathogenesis of Alzheimer's Disease. Mol Cells 2019; 42:739-746. [PMID: 31711277 PMCID: PMC6883979 DOI: 10.14348/molcells.2019.0200] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/13/2019] [Accepted: 10/20/2019] [Indexed: 11/27/2022] Open
Abstract
Significant knowledge about the pathophysiology of Alzheimer's disease (AD) has been gained in the last century; however, the understanding of its causes of onset remains limited. Late-onset AD is observed in about 95% of patients, and APOE4-encoding apolipoprotein E4 (ApoE4) is strongly associated with these cases. As an apolipoprotein, the function of ApoE in brain cholesterol transport has been extensively studied and widely appreciated. Development of new technologies such as human-induced pluripotent stem cells (hiPSCs) and CRISPR-Cas9 genome editing tools have enabled us to develop human brain model systems in vitro and readily manipulate genomic information. In the context of these advances, recent studies provide strong evidence that abnormal cholesterol metabolism by ApoE4 could be linked to AD-associated pathology. In this review, we discuss novel discoveries in brain cholesterol dysregulation by ApoE4. We further elaborate cell type-specific roles in cholesterol regulation of four major brain cell types, neurons, astrocytes, microglia, and oligodendrocytes, and how its dysregulation can be linked to AD pathology.
Collapse
Affiliation(s)
- Woojin Jeong
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988,
Korea
| | - Hyein Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988,
Korea
| | - Sukhee Cho
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988,
Korea
| | - Jinsoo Seo
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988,
Korea
| |
Collapse
|
4
|
Loftis JM, Taylor J, Hudson R, Firsick EJ. Neuroinvasion and cognitive impairment in comorbid alcohol dependence and chronic viral infection: An initial investigation. J Neuroimmunol 2019; 335:577006. [PMID: 31325774 DOI: 10.1016/j.jneuroim.2019.577006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/03/2019] [Accepted: 07/09/2019] [Indexed: 12/16/2022]
Abstract
Viruses that invade the central nervous system (CNS) can cause neuropsychiatric impairments. Similarly, chronic alcohol exposure can induce inflammatory responses that alter brain function. However, the effects of a chronic viral infection and comorbid alcohol use on neuroinflammation and behavior are not well-defined. We investigated the role of heavy alcohol intake in regulating inflammatory responses and behavioral signs of cognitive impairments in mice infected with lymphocytic choriomeningitis virus (LCMV) clone 13. LCMV-infected mice exposed to alcohol had increased peripheral inflammation and impaired cognitive function (as indicated by performance on the novel object recognition test). Initial findings suggest that brain region-specific dysregulation of microglial response to viral infection may contribute to cognitive impairments in the context of heavy alcohol use.
Collapse
Affiliation(s)
- Jennifer M Loftis
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA; Methamphetamine Abuse Research Center, Veterans Affairs Portland Health Care System, Oregon Health & Science University, Portland, OR, USA.
| | - Jonathan Taylor
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Rebekah Hudson
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Evan J Firsick
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA
| |
Collapse
|
5
|
Pinheiro IRR, Melo MFN, de Sousa SV, Cardoso BG, da Silva TM, Rangel LP, Cortes VF, de Lima Santos H, Chaves VE, Garcia IJP, Barbosa LA. Evaluation of the effect of cafeteria diet on the kidney Na,K-ATPase activity, and oxidative stress. J Cell Biochem 2019; 120:19052-19063. [PMID: 31265167 DOI: 10.1002/jcb.29228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 06/04/2019] [Indexed: 11/07/2022]
Abstract
In this study, renal tissue, subdivided into the cortex and medulla of Wistar rats subjected to a cafeteria diet (CAF) for 24 days or to normal diet, was used to analyze whether the renal enzyme Na,K-ATPase activity was modified by CAF diet, as well as to analyze the α1 subunit of renal Na,K-ATPase expression levels. The lipid profile of the renal plasma membrane and oxidative stress were verified. In the Na,K-ATPase activity evaluation, no alteration was found, but a significant decrease of 30% in the cortex was detected in the α1 subunit expression of the enzyme. There was a 24% decrease in phospholipids in the cortex of rats submitted to CAF, a 17% increase in cholesterol levels in the cortex, and a 23% decrease in the medulla. Lipid peroxidation was significantly increased in the groups submitted to CAF, both in the cortical region, 29%, and in the medulla, 35%. Also, a reduction of 45% in the glutathione levels was observed in the cortex and medulla with CAF. CAF showed a nearly two-fold increase in glutathione peroxidase (GPX) activity in relation to the control group in the cortex and a 59% increase in the GPx activity in the medulla. In conclusion, although the diet was administered for a short period of time, important results were found, especially those related to the lipid profile and oxidative stress, which may directly affect renal function.
Collapse
Affiliation(s)
- Isadora Reis Restier Pinheiro
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Marina Fátima Nunes Melo
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Sarah Vivas de Sousa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Bárbara Gatti Cardoso
- Laboratório de Fisiologia, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Thaís Marques da Silva
- Laboratório de Fisiologia, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Luciana Pereira Rangel
- Laboratório de Bioquímica Tumoral, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vanessa Faria Cortes
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil.,Laboratório de de Bioquímica de Membranas e ATPases, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Hérica de Lima Santos
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil.,Laboratório de de Bioquímica de Membranas e ATPases, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Valéria Ernestânia Chaves
- Laboratório de Fisiologia, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Israel José Pereira Garcia
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil.,Laboratório de de Bioquímica de Membranas e ATPases, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| | - Leandro Augusto Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil.,Laboratório de de Bioquímica de Membranas e ATPases, Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, Minas Gerais, Brazil
| |
Collapse
|
6
|
Vazquez L, Teixeira da Silva Ferreira A, Cavalcante FS, Garcia IJP, Dos Santos KRN, Barbosa LADO, Almeida MDS, Mignaco JA, Fontes CFL. Properties of novel surfactin-derived biosurfactants obtained through solid-phase synthesis. J Pept Sci 2018; 24:e3129. [PMID: 30325566 DOI: 10.1002/psc.3129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 08/28/2018] [Accepted: 09/09/2018] [Indexed: 12/19/2022]
Abstract
Eight molecules, four peptides (SPs) and four lipopeptides (LPs) derived by rational design from surfactin, a well-known secreted biosurfactant from Bacillus subtilis, were produced employing Fmoc-based solid-phase synthesis. These new peptides were tested to evaluate their potential biosurfactant and biological activities, aiming at possible applications in industrial, biological, pharmaceutical, and medical use. Five molecules (SP1, SP2, SP4, LP5, and LP8) presented potential for medical uses, mainly due to their drug delivery properties as suggested by their synergistic activity with the antibiotic vancomycin against Staphylococcus aureus. All synthetic peptides showed low toxicity against Vero cell cultures, in assays of hemolysis, and in different cytotoxicity assays. In addition, we found that three peptides (SP1, LP6, and LP7) had potential technological and industrial use because of their emulsifying capacity, low toxicity, and ability to physically stabilize solutions. These novel molecules retained some properties of the parental molecule (surfactin, which was originally obtained through nonribosomal synthesis in Bacillus subtilis) but have the advantage of being linear peptides, which can be produced at large scales through the use of conventional heterologous protein expression protocols.
Collapse
Affiliation(s)
- Leonardo Vazquez
- Programa de Biologia Estrutural, Lab. Est. e Reg. de Proteínas e ATPases, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Fernanda Sampaio Cavalcante
- Departamento de Microbiologia, Campus Macaé, Depto. Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Israel José P Garcia
- Department of Biochemistry, Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil
| | | | - Leandro Augusto de Oliveira Barbosa
- Department of Biochemistry, Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil
| | - Marcius da Silva Almeida
- Programa de Biologia Estrutural, Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Julio Alberto Mignaco
- Programa de Biologia Estrutural, Lab. Est. e Reg. de Proteínas e ATPases, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos Frederico Leite Fontes
- Programa de Biologia Estrutural, Lab. Est. e Reg. de Proteínas e ATPases, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
7
|
Cougnoux A, Drummond RA, Collar AL, Iben JR, Salman A, Westgarth H, Wassif CA, Cawley NX, Farhat NY, Ozato K, Lionakis MS, Porter FD. Microglia activation in Niemann-Pick disease, type C1 is amendable to therapeutic intervention. Hum Mol Genet 2018; 27:2076-2089. [PMID: 29617956 PMCID: PMC5985727 DOI: 10.1093/hmg/ddy112] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/06/2018] [Accepted: 03/26/2018] [Indexed: 12/12/2022] Open
Abstract
Niemann-Pick disease, type C1 (NPC1) is a neurodegenerative disorder with limited treatment options. NPC1 is associated with neuroinflammation; however, attempts to therapeutically target neuroinflammation in NPC1 have had mixed success. We show here that NPC1 neuroinflammation is characterized by an atypical microglia activation phenotype. Specifically, Npc1-/- microglia demonstrated altered morphology, reduced levels of lineage markers and a shift toward glycolytic metabolism. Treatment with 2-hydroxypropyl-β-cyclodextrin (HPβCD), a drug currently being studied in a phase 2b/3 clinical trial, reversed all microglia-associated defects in Npc1-/- animals. In addition, impairing microglia mediated neuroinflammation by genetic deletion of IRF8 led to decreased symptoms and increased lifespan. We identified CD22 as a marker of dysregulated microglia in Npc1 mutant mice and subsequently demonstrated that elevated cerebrospinal fluid levels of CD22 in NPC1 patients responds to HPβCD administration. Collectively, these data provide the first in-depth analysis of microglia function in NPC1 and suggest possible new therapeutic approaches.
Collapse
Affiliation(s)
- Antony Cougnoux
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Rebecca A Drummond
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20879, USA
| | - Amanda L Collar
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20879, USA
| | - James R Iben
- Molecular Genomics Core, National Institutes of Health, Bethesda, MD 20879, USA
| | - Alexander Salman
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Harrison Westgarth
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Christopher A Wassif
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Niamh X Cawley
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Nicole Y Farhat
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| | - Keiko Ozato
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20879, USA
| | - Michail S Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20879, USA
| | - Forbes D Porter
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, , Bethesda, MD 20879, USA
| |
Collapse
|
8
|
Garcia IJP, Cézar JS, Lemos BS, Silva LN, Ribeiro RIMDA, Santana CC, Grillo LAM, Pinto FCH, Buzelle SL, Cortes VF, Santos HDL, Santos MESMD, Barbosa LA. Effects of high fat diet on kidney lipid content and the Na,K-ATPase activity. BRAZ J PHARM SCI 2018. [DOI: 10.1590/s2175-97902018000117165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
9
|
Parreira GM, Resende MDA, Garcia IJP, Sartori DB, Umeoka EHDL, Godoy LD, Garcia-Cairasco N, Barbosa LA, Santos HDL, Tilelli CQ. Oxidative stress and Na,K-ATPase activity differential regulation in brainstem and forebrain of Wistar Audiogenic rats may lead to increased seizure susceptibility. Brain Res 2018; 1679:171-178. [DOI: 10.1016/j.brainres.2017.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/30/2017] [Accepted: 12/01/2017] [Indexed: 11/16/2022]
|
10
|
Garcia IJP, Kinoshita PF, Braga I, Parreira GM, Mignaco JA, Scavone C, Barbosa LA, Santos H. Ouabain attenuates the oxidative stress induced by lipopolysaccharides in the cerebellum of rats. J Cell Biochem 2017; 119:2156-2167. [DOI: 10.1002/jcb.26377] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/24/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Israel José Pereira Garcia
- Laboratório de Bioquímica Celular, Universidade Federal de São João del ReiCampus Centro‐Oeste Dona LinduDivinópolisMGBrazil
| | - Paula Fernanda Kinoshita
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical ScienceUniversity of São PauloSão PauloBrazil
| | - Italo Braga
- Laboratório de Bioquímica Celular, Universidade Federal de São João del ReiCampus Centro‐Oeste Dona LinduDivinópolisMGBrazil
| | - Gabriela Machado Parreira
- Laboratório de Bioquímica Celular, Universidade Federal de São João del ReiCampus Centro‐Oeste Dona LinduDivinópolisMGBrazil
| | - Julio Alberto Mignaco
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da SaúdeUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
| | - Cristoforo Scavone
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical ScienceUniversity of São PauloSão PauloBrazil
| | - Leandro Augusto Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del ReiCampus Centro‐Oeste Dona LinduDivinópolisMGBrazil
| | - Hérica Santos
- Laboratório de Bioquímica Celular, Universidade Federal de São João del ReiCampus Centro‐Oeste Dona LinduDivinópolisMGBrazil
| |
Collapse
|
11
|
Perturbed cholesterol homeostasis in aging spinal cord. Neurobiol Aging 2016; 45:123-135. [PMID: 27459933 DOI: 10.1016/j.neurobiolaging.2016.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 04/28/2016] [Accepted: 05/16/2016] [Indexed: 12/14/2022]
Abstract
The spinal cord is vital for the processing of sensorimotor information and for its propagation to and from both the brain and the periphery. Spinal cord function is affected by aging, however, the mechanisms involved are not well-understood. To characterize molecular mechanisms of spinal cord aging, microarray analyses of gene expression were performed on cervical spinal cords of aging rats. Of the metabolic and signaling pathways affected, cholesterol-associated pathways were the most comprehensively altered, including significant downregulation of cholesterol synthesis-related genes and upregulation of cholesterol transport and metabolism genes. Paradoxically, a significant increase in total cholesterol content was observed-likely associated with cholesterol ester accumulation. To investigate potential mechanisms for the perturbed cholesterol homeostasis, we quantified the expression of myelin and neuroinflammation-associated genes and proteins. Although there was minimal change in myelin-related expression, there was an increase in phagocytic microglial and astrogliosis markers, particularly in the white matter. Together, these results suggest that perturbed cholesterol homeostasis, possibly as a result of increased inflammatory activation in spinal cord white matter, may contribute to impaired spinal cord function with aging.
Collapse
|
12
|
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: 120] [Impact Index Per Article: 13.3] [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.
Collapse
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
| |
Collapse
|
13
|
Cholesterol overload impairing cerebellar function: The promise of natural products. Nutrition 2015; 31:621-30. [DOI: 10.1016/j.nut.2014.10.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 10/19/2014] [Accepted: 10/21/2014] [Indexed: 11/20/2022]
|
14
|
Masoud R, Bizouarn T, Houée-Levin C. Cholesterol: A modulator of the phagocyte NADPH oxidase activity - A cell-free study. Redox Biol 2014; 3:16-24. [PMID: 25462061 PMCID: PMC4221629 DOI: 10.1016/j.redox.2014.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/02/2014] [Accepted: 10/12/2014] [Indexed: 01/26/2023] Open
Abstract
The NADPH oxidase Nox2, a multi-subunit enzyme complex comprising membrane and cytosolic proteins, catalyzes a very intense production of superoxide ions O2•−, which are transformed into other reactive oxygen species (ROS). In vitro, it has to be activated by addition of amphiphiles like arachidonic acid (AA). It has been shown that the membrane part of phagocyte NADPH oxidase is present in lipid rafts rich in cholesterol. Cholesterol plays a significant role in the development of cardio-vascular diseases that are always accompanied by oxidative stress. Our aim was to investigate the influence of cholesterol on the activation process of NADPH oxidase. Our results clearly show that, in a cell-free system, cholesterol is not an efficient activator of NADPH oxidase like arachidonic acid (AA), however it triggers a basal low superoxide production at concentrations similar to what found in neutrophile. A higher concentration, if present during the assembly process of the enzyme, has an inhibitory role on the production of O2•−. Added cholesterol acts on both cytosolic and membrane components, leading to imperfect assembly and decreasing the affinity of cytosolic subunits to the membrane ones. Added to the cytosolic proteins, it retains their conformations but still allows some conformational change induced by AA addition, indispensable to activation of NADPH oxidase. Natural cholesterol is important for the NADPH oxidase function. Added cholesterol alone activates slightly the NADPH oxidase. Cholesterol addition lowers the AA dependent activity of NADPH oxidase. Added cholesterol acts on both cytosolic and membrane components.
Collapse
Affiliation(s)
- Rawand Masoud
- Laboratoire de chimie physique, UMR 8000, Université Paris Sud-CNRS, Orsay 91405, France
| | - Tania Bizouarn
- Laboratoire de chimie physique, UMR 8000, Université Paris Sud-CNRS, Orsay 91405, France
| | - Chantal Houée-Levin
- Laboratoire de chimie physique, UMR 8000, Université Paris Sud-CNRS, Orsay 91405, France.
| |
Collapse
|
15
|
Aguilar D, deOgburn RC, Volek JS, Fernandez ML. Cholesterol-induced inflammation and macrophage accumulation in adipose tissue is reduced by a low carbohydrate diet in guinea pigs. Nutr Res Pract 2014; 8:625-31. [PMID: 25489401 PMCID: PMC4252521 DOI: 10.4162/nrp.2014.8.6.625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/21/2014] [Accepted: 07/25/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND/OBJECTIVES The main objective of this study was to evaluate the effects of a high cholesterol (HC) dietary challenge on cholesterol tissue accumulation, inflammation, adipocyte differentiation, and macrophage infiltration in guinea pigs. A second objective was to assess whether macronutrient manipulation would reverse these metabolic alterations. MATERIALS/METHODS Male Hartley guinea pigs (10/group) were assigned to either low cholesterol (LC) (0.04g/100g) or high cholesterol (HC) (0.25g/100g) diets for six weeks. For the second experiment, 20 guinea pigs were fed the HC diet for six weeks and then assigned to either a low carbohydrate (CHO) diet (L-CHO) (10% energy from CHO) or a high CHO diet (H-CHO) (54% CHO) for an additional six weeks. RESULTS Higher concentrations of total (P < 0.005) and free (P < 0.05) cholesterol were observed in both adipose tissue and aortas of guinea pigs fed the HC compared to those in the LC group. In addition, higher concentrations of pro-inflammatory cytokines in the adipose tissue (P < 0.005) and lower concentrations of anti-inflammatory interleukin (IL)-10 were observed in the HC group (P < 0.05) compared to the LC group. Of particular interest, adipocytes in the HC group were smaller in size (P < 0.05) and showed increased macrophage infiltration compared to the LC group. When compared to the H-CHO group, lower concentrations of cholesterol in both adipose and aortas as well as lower concentrations of inflammatory cytokines in adipose tissue were observed in the L-CHO group (P < 0.05). In addition, guinea pigs fed the L-CHO exhibited larger adipose cells and lower macrophage infiltration compared to the H-CHO group. CONCLUSIONS The results of this study strongly suggest that HC induces metabolic dysregulation associated with inflammation in adipose tissue and that L-CHO is more effective than H-CHO in attenuating these detrimental effects.
Collapse
Affiliation(s)
- David Aguilar
- Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Ext, U 4017, Storrs, CT 6269, USA
| | - Ryan C deOgburn
- Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Ext, U 4017, Storrs, CT 6269, USA
| | - Jeff S Volek
- Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Ext, U 4017, Storrs, CT 6269, USA. ; Department of Kinesiology, University of Connecticut, USA
| | - Maria Luz Fernandez
- Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Ext, U 4017, Storrs, CT 6269, USA
| |
Collapse
|
16
|
Oxidative tissue injury in multiple sclerosis is only partly reflected in experimental disease models. Acta Neuropathol 2014; 128:247-66. [PMID: 24622774 PMCID: PMC4102830 DOI: 10.1007/s00401-014-1263-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/22/2014] [Accepted: 02/17/2014] [Indexed: 12/22/2022]
Abstract
Recent data suggest that oxidative injury may play an important role in demyelination and neurodegeneration in multiple sclerosis (MS). We compared the extent of oxidative injury in MS lesions with that in experimental models driven by different inflammatory mechanisms. It was only in a model of coronavirus-induced demyelinating encephalomyelitis that we detected an accumulation of oxidised phospholipids, which was comparable in extent to that in MS. In both, MS and coronavirus-induced encephalomyelitis, this was associated with massive microglial and macrophage activation, accompanied by the expression of the NADPH oxidase subunit p22phox but only sparse expression of inducible nitric oxide synthase (iNOS). Acute and chronic CD4+ T cell-mediated experimental autoimmune encephalomyelitis lesions showed transient expression of p22phox and iNOS associated with inflammation. Macrophages in chronic lesions of antibody-mediated demyelinating encephalomyelitis showed lysosomal activity but very little p22phox or iNOS expressions. Active inflammatory demyelinating lesions induced by CD8+ T cells or by innate immunity showed macrophage and microglial activation together with the expression of p22phox, but low or absent iNOS reactivity. We corroborated the differences between acute CD4+ T cell-mediated experimental autoimmune encephalomyelitis and acute MS lesions via gene expression studies. Furthermore, age-dependent iron accumulation and lesion-associated iron liberation, as occurring in the human brain, were only minor in rodent brains. Our study shows that oxidative injury and its triggering mechanisms diverge in different models of rodent central nervous system inflammation. The amplification of oxidative injury, which has been suggested in MS, is only reflected to a limited degree in the studied rodent models.
Collapse
|