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Yi W, Lv D, Sun Y, Mu J, Lu X. Role of APOE in glaucoma. Biochem Biophys Res Commun 2024; 694:149414. [PMID: 38145596 DOI: 10.1016/j.bbrc.2023.149414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 12/27/2023]
Abstract
Glaucoma is a chronic blinding eye disease caused by the progressive loss of retinal ganglion cells (RGCs). Currently, no clinically approved treatment can directly improve the survival rate of RGCs. The Apolipoprotein E (APOE) gene is closely related to the genetic risk of numerous neurodegenerative diseases and has become a hot topic in the field of neurodegenerative disease research in recent years. The optic nerve and retina are extensions of the brain's nervous system. The pathogenesis of retinal degenerative diseases is closely related to the degenerative diseases of the nerves in the brain. APOE consists of three alleles, ε4, ε3, and ε2, in a single locus. They have varying degrees of risk for glaucoma. APOE4 and the APOE gene deletion (APOE-/-) can reduce RGC loss. By contrast, APOE3 and the overall presence of APOE genes (APOE+/+) result in significant loss of RGC bodies and axons, increasing the risk of glaucoma RGCs death. Currently, there is no clear literature indicating that APOE2 is beneficial or harmful to glaucoma. This study summarises the mechanism of different APOE genes in glaucoma and speculates that APOE targeted intervention may be a promising method for protecting against RGCs loss in glaucoma.
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Affiliation(s)
- Wenhua Yi
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - De Lv
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, China.
| | - Yue Sun
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Jingyu Mu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Xuejing Lu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China; Ineye Hospital of Chengdu University of TCM, Chengdu City, Sichuan province, China; Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu City, Sichuan province, China; Retinal Image Technology and Chronic Vascular Disease Prevention&Control and Collaborative Innovation Center, Chengdu City, Sichuan province, China.
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2
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Gao Y, Ye S, Tang Y, Tong W, Sun S. Brain cholesterol homeostasis and its association with neurodegenerative diseases. Neurochem Int 2023; 171:105635. [PMID: 37949118 DOI: 10.1016/j.neuint.2023.105635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/17/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023]
Abstract
The brain is the most cholesterol-rich organ in mammals. However, cholesterol metabolism in the brain is completely independent of other tissues due to the presence of the blood-brain barrier (BBB). Neurons, astrocytes and oligodendrocytes are the main cells responsible for cholesterol synthesis in the brain. The cholesterol content in the brain is maintained at a relatively constant level under strict regulation of synthesis, transport, and turnover, that is, brain cholesterol homeostasis. Once this balance is disrupted, neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD) ensue. This review summarizes the processes controlling cholesterol homeostasis with respect to the synthesis, transport and turnover of cholesterol in the brain. We further focus on how cholesterol imbalance contributes to neurodegenerative diseases to explore the possibilities to modulate the key steps involved, which will provide clues for the development of therapies for the treatment of central nervous system (CNS) diseases.
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Affiliation(s)
- Yi Gao
- Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Shiying Ye
- Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Yuehong Tang
- Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Wenjuan Tong
- Department of Gynecology and Obstetrics, First Affiliated Hospital, University of South China, Hengyang, Hunan, 421001, China.
| | - Shaowei Sun
- Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China.
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3
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Yang LG, March ZM, Stephenson RA, Narayan PS. Apolipoprotein E in lipid metabolism and neurodegenerative disease. Trends Endocrinol Metab 2023; 34:430-445. [PMID: 37357100 PMCID: PMC10365028 DOI: 10.1016/j.tem.2023.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 06/27/2023]
Abstract
Dysregulation of lipid metabolism has emerged as a central component of many neurodegenerative diseases. Variants of the lipid transport protein, apolipoprotein E (APOE), modulate risk and resilience in several neurodegenerative diseases including late-onset Alzheimer's disease (LOAD). Allelic variants of the gene, APOE, alter the lipid metabolism of cells and tissues and have been broadly associated with several other cellular and systemic phenotypes. Targeting APOE-associated metabolic pathways may offer opportunities to alter disease-related phenotypes and consequently, attenuate disease risk and impart resilience to multiple neurodegenerative diseases. We review the molecular, cellular, and tissue-level alterations to lipid metabolism that arise from different APOE isoforms. These changes in lipid metabolism could help to elucidate disease mechanisms and tune neurodegenerative disease risk and resilience.
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Affiliation(s)
- Linda G Yang
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Zachary M March
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Roxan A Stephenson
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Priyanka S Narayan
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.; National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, USA; Center for Alzheimer's and Related Dementias (CARD), National Institutes of Health, Bethesda, MD, USA.
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4
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Valencia-Olvera AC, Balu D, Faulk N, Amiridis A, Wang Y, Pham C, Avila-Munoz E, York JM, Thatcher GRJ, LaDu MJ. Inhibition of ACAT as a Therapeutic Target for Alzheimer's Disease Is Independent of ApoE4 Lipidation. Neurotherapeutics 2023; 20:1120-1137. [PMID: 37157042 PMCID: PMC10457278 DOI: 10.1007/s13311-023-01375-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2023] [Indexed: 05/10/2023] Open
Abstract
APOE4, encoding apolipoprotein E4 (apoE4), is the greatest genetic risk factor for Alzheimer's disease (AD), compared to the common APOE3. While the mechanism(s) underlying APOE4-induced AD risk remains unclear, increasing the lipidation of apoE4 is an important therapeutic target as apoE4-lipoproteins are poorly lipidated compared to apoE3-lipoproteins. ACAT (acyl-CoA: cholesterol-acyltransferase) catalyzes the formation of intracellular cholesteryl-ester droplets, reducing the intracellular free cholesterol (FC) pool. Thus, inhibiting ACAT increases the FC pool and facilitates lipid secretion to extracellular apoE-containing lipoproteins. Previous studies using commercial ACAT inhibitors, including avasimibe (AVAS), as well as ACAT-knock out (KO) mice, exhibit reduced AD-like pathology and amyloid precursor protein (APP) processing in familial AD (FAD)-transgenic (Tg) mice. However, the effects of AVAS with human apoE4 remain unknown. In vitro, AVAS induced apoE efflux at concentrations of AVAS measured in the brains of treated mice. AVAS treatment of male E4FAD-Tg mice (5xFAD+/-APOE4+/+) at 6-8 months had no effect on plasma cholesterol levels or distribution, the original mechanism for AVAS treatment of CVD. In the CNS, AVAS reduced intracellular lipid droplets, indirectly demonstrating target engagement. Surrogate efficacy was demonstrated by an increase in Morris water maze measures of memory and postsynaptic protein levels. Amyloid-beta peptide (Aβ) solubility/deposition and neuroinflammation were reduced, critical components of APOE4-modulated pathology. However, there was no increase in apoE4 levels or apoE4 lipidation, while amyloidogenic and non-amyloidogenic processing of APP were significantly reduced. This suggests that the AVAS-induced reduction in Aβ via reduced APP processing was sufficient to reduce AD pathology, as apoE4-lipoproteins remained poorly lipidated.
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Affiliation(s)
- Ana C. Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Naomi Faulk
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | | | - Yueting Wang
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60612 USA
- Present Address: AbbVie Inc., 1 N. Waukegan Road, North Chicago, IL 60064 USA
| | - Christine Pham
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Eva Avila-Munoz
- Syneos Health, Av. Gustavo Baz 309, La Loma, Tlalnepantla de Baz, 54060 Mexico
| | - Jason M. York
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Gregory R. J. Thatcher
- Department of Pharmacology & Toxicology, University of Arizona, 1703 E Mabel St., Tucson, AZ 85721 USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
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Dhote VV, Samundre P, Upaganlawar AB, Ganeshpurkar A. Gene Therapy for Chronic Traumatic Brain Injury: Challenges in Resolving Long-term Consequences of Brain Damage. Curr Gene Ther 2023; 23:3-19. [PMID: 34814817 DOI: 10.2174/1566523221666211123101441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 02/08/2023]
Abstract
The gene therapy is alluring not only for CNS disorders but also for other pathological conditions. Gene therapy employs the insertion of a healthy gene into the identified genome to replace or replenish genes responsible for pathological disorder or damage due to trauma. The last decade has seen a drastic change in the understanding of vital aspects of gene therapy. Despite the complexity of traumatic brain injury (TBI), the advent of gene therapy in various neurodegenerative disorders has reinforced the ongoing efforts of alleviating TBI-related outcomes with gene therapy. The review highlights the genes modulated in response to TBI and evaluates their impact on the severity and duration of the injury. We have reviewed strategies that pinpointed the most relevant gene targets to restrict debilitating events of brain trauma and utilize vector of choice to deliver the gene of interest at the appropriate site. We have made an attempt to summarize the long-term neurobehavioral consequences of TBI due to numerous pathometabolic perturbations associated with a plethora of genes. Herein, we shed light on the basic pathological mechanisms of brain injury, genetic polymorphism in individuals susceptible to severe outcomes, modulation of gene expression due to TBI, and identification of genes for their possible use in gene therapy. The review also provides insights on the use of vectors and challenges in translations of this gene therapy to clinical practices.
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Affiliation(s)
- Vipin V Dhote
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP, 462044, India
| | - Prem Samundre
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP, 462044, India
| | - Aman B Upaganlawar
- SNJB's Shree Sureshdada Jain College of Pharmacy, Chandwad, Nasik, Maharashtra, 423101, India
| | - Aditya Ganeshpurkar
- Department of Pharmacy, Shri Ram Institute of Technology, Jabalpur, MP, India
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6
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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.
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7
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Hartmann H, Ho WY, Chang JC, Ling SC. Cholesterol dyshomeostasis in amyotrophic lateral sclerosis: cause, consequence, or epiphenomenon? FEBS J 2022; 289:7688-7709. [PMID: 34469619 DOI: 10.1111/febs.16175] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/10/2021] [Accepted: 08/31/2021] [Indexed: 01/14/2023]
Abstract
Amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disease, is characterized by the selective degeneration of motor neurons leading to paralysis and eventual death. Multiple pathogenic mechanisms, including systemic dysmetabolism, have been proposed to contribute to ALS. Among them, dyslipidemia, i.e., abnormal level of cholesterol and other lipids in the circulation and central nervous system (CNS), has been reported in ALS patients, but without a consensus. Cholesterol is a constituent of cellular membranes and a precursor of steroid hormones, oxysterols, and bile acids. Consequently, optimal cholesterol levels are essential for health. Due to the blood-brain barrier (BBB), cholesterol cannot move between the CNS and the rest of the body. As such, cholesterol metabolism in the CNS is proposed to operate autonomously. Despite its importance, it remains elusive how cholesterol dyshomeostasis may contribute to ALS. In this review, we aim to describe the current state of cholesterol metabolism research in ALS, identify unresolved issues, and provide potential directions.
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Affiliation(s)
- Hannelore Hartmann
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wan Yun Ho
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jer-Cherng Chang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shuo-Chien Ling
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Healthy Longevity Translational Research Programme, National University Health System, Singapore, Singapore.,Program in Neuroscience and Behavior Disorders, Duke-NUS Medical School, Singapore, Singapore
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8
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Asante I, Louie S, Yassine HN. Uncovering mechanisms of brain inflammation in Alzheimer's disease with APOE4: Application of single cell-type lipidomics. Ann N Y Acad Sci 2022; 1518:84-105. [PMID: 36200578 PMCID: PMC10092192 DOI: 10.1111/nyas.14907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A chronic state of unresolved inflammation in Alzheimer's disease (AD) is intrinsically involved with the remodeling of brain lipids. This review highlights the effect of carrying the apolipoprotein E ε4 allele (APOE4) on various brain cell types in promoting an unresolved inflammatory state. Among its pleotropic effects on brain lipids, we focus on APOE4's activation of Ca2+ -dependent phospholipase A2 (cPLA2) and its effects on arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid signaling cascades in the brain. During the process of neurodegeneration, various brain cell types, such as astrocytes, microglia, and neurons, together with the neurovascular unit, develop distinct inflammatory phenotypes that impact their functions and have characteristic lipidomic fingerprints. We propose that lipidomic phenotyping of single cell-types harvested from brains differing by age, sex, disease severity stage, and dietary and genetic backgrounds can be employed to probe mechanisms of neurodegeneration. A better understanding of the brain cellular inflammatory/lipidomic response promises to guide the development of nutritional and drug interventions for AD dementia.
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Affiliation(s)
- Isaac Asante
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Stan Louie
- School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Hussein N Yassine
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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9
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Lennol MP, Sánchez-Domínguez I, Cuchillo-Ibañez I, Camporesi E, Brinkmalm G, Alcolea D, Fortea J, Lleó A, Soria G, Aguado F, Zetterberg H, Blennow K, Sáez-Valero J. Apolipoprotein E imbalance in the cerebrospinal fluid of Alzheimer's disease patients. Alzheimers Res Ther 2022; 14:161. [PMID: 36324176 PMCID: PMC9628034 DOI: 10.1186/s13195-022-01108-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this study was to examine the levels of cerebrospinal fluid (CSF) apolipoprotein E (apoE) species in Alzheimer's disease (AD) patients. METHODS We analyzed two CSF cohorts of AD and control individuals expressing different APOE genotypes. Moreover, CSF samples from the TgF344-AD rat model were included. Samples were run in native- and SDS-PAGE under reducing or non-reducing conditions (with or without β-mercaptoethanol). Immunoprecipitation combined with mass spectrometry or western blotting analyses served to assess the identity of apoE complexes. RESULTS In TgF344-AD rats expressing a unique apoE variant resembling human apoE4, a ~35-kDa apoE monomer was identified, increasing at 16.5 months compared with wild-types. In humans, apoE isoforms form disulfide-linked dimers in CSF, except apoE4, which lacks a cysteine residue. Thus, controls showed a decrease in the apoE dimer/monomer quotient in the APOE ε3/ε4 group compared with ε3/ε3 by native electrophoresis. A major contribution of dimers was found in APOE ε3/ε4 AD cases, and, unexpectedly, dimers were also found in ε4/ε4 AD cases. Under reducing conditions, two apoE monomeric glycoforms at 36 kDa and at 34 kDa were found in all human samples. In AD patients, the amount of the 34-kDa species increased, while the 36-kDa/34-kDa quotient was lower compared with controls. Interestingly, under reducing conditions, a ~100-kDa apoE complex, the identity of which was confirmed by mass spectrometry, also appeared in human AD individuals across all APOE genotypes, suggesting the occurrence of aberrantly resistant apoE aggregates. A second independent cohort of CSF samples validated these results. CONCLUSION These results indicate that despite the increase in total apoE content the apoE protein is altered in AD CSF, suggesting that function may be compromised.
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Affiliation(s)
- Matthew Paul Lennol
- grid.466805.90000 0004 1759 6875Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550 Sant Joan d’Alacant, Spain ,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d’Alacant, Spain
| | - Irene Sánchez-Domínguez
- grid.5841.80000 0004 1937 0247Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain ,grid.5841.80000 0004 1937 0247Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Inmaculada Cuchillo-Ibañez
- grid.466805.90000 0004 1759 6875Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550 Sant Joan d’Alacant, Spain ,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d’Alacant, Spain ,grid.513062.30000 0004 8516 8274Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), Alicante, Spain
| | - Elena Camporesi
- grid.8761.80000 0000 9919 9582Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Gunnar Brinkmalm
- grid.8761.80000 0000 9919 9582Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Daniel Alcolea
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d’Alacant, Spain ,grid.7080.f0000 0001 2296 0625Sant Pau Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Juan Fortea
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d’Alacant, Spain ,grid.7080.f0000 0001 2296 0625Sant Pau Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain ,Barcelona Down Medical Center, Fundació Catalana Síndrome de Down, Barcelona, Spain
| | - Alberto Lleó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d’Alacant, Spain ,grid.7080.f0000 0001 2296 0625Sant Pau Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Guadalupe Soria
- grid.5841.80000 0004 1937 0247Institute of Neurosciences, University of Barcelona, Barcelona, Spain ,grid.5841.80000 0004 1937 0247Laboratory of Surgical Neuroanatomy, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Fernando Aguado
- grid.5841.80000 0004 1937 0247Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain ,grid.5841.80000 0004 1937 0247Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Henrik Zetterberg
- grid.8761.80000 0000 9919 9582Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden ,grid.1649.a000000009445082XClinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden ,grid.83440.3b0000000121901201Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK ,grid.83440.3b0000000121901201UK Dementia Research Institute at UCL, London, UK ,grid.24515.370000 0004 1937 1450Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Kaj Blennow
- grid.8761.80000 0000 9919 9582Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden ,grid.1649.a000000009445082XClinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550, Sant Joan d'Alacant, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain. .,Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), Alicante, Spain.
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Steele OG, Stuart AC, Minkley L, Shaw K, Bonnar O, Anderle S, Penn AC, Rusted J, Serpell L, Hall C, King S. A multi-hit hypothesis for an APOE4-dependent pathophysiological state. Eur J Neurosci 2022; 56:5476-5515. [PMID: 35510513 PMCID: PMC9796338 DOI: 10.1111/ejn.15685] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/31/2022] [Accepted: 04/25/2022] [Indexed: 01/01/2023]
Abstract
The APOE gene encoding the Apolipoprotein E protein is the single most significant genetic risk factor for late-onset Alzheimer's disease. The APOE4 genotype confers a significantly increased risk relative to the other two common genotypes APOE3 and APOE2. Intriguingly, APOE4 has been associated with neuropathological and cognitive deficits in the absence of Alzheimer's disease-related amyloid or tau pathology. Here, we review the extensive literature surrounding the impact of APOE genotype on central nervous system dysfunction, focussing on preclinical model systems and comparison of APOE3 and APOE4, given the low global prevalence of APOE2. A multi-hit hypothesis is proposed to explain how APOE4 shifts cerebral physiology towards pathophysiology through interconnected hits. These hits include the following: neurodegeneration, neurovascular dysfunction, neuroinflammation, oxidative stress, endosomal trafficking impairments, lipid and cellular metabolism disruption, impaired calcium homeostasis and altered transcriptional regulation. The hits, individually and in combination, leave the APOE4 brain in a vulnerable state where further cumulative insults will exacerbate degeneration and lead to cognitive deficits in the absence of Alzheimer's disease pathology and also a state in which such pathology may more easily take hold. We conclude that current evidence supports an APOE4 multi-hit hypothesis, which contributes to an APOE4 pathophysiological state. We highlight key areas where further study is required to elucidate the complex interplay between these individual mechanisms and downstream consequences, helping to frame the current landscape of existing APOE-centric literature.
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Affiliation(s)
| | | | - Lucy Minkley
- School of Life SciencesUniversity of SussexBrightonUK
| | - Kira Shaw
- School of Life SciencesUniversity of SussexBrightonUK
| | - Orla Bonnar
- School of Life SciencesUniversity of SussexBrightonUK
| | | | | | | | | | | | - Sarah King
- School of PsychologyUniversity of SussexBrightonUK
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11
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Borràs C, Mercer A, Sirisi S, Alcolea D, Escolà-Gil JC, Blanco-Vaca F, Tondo M. HDL-like-Mediated Cell Cholesterol Trafficking in the Central Nervous System and Alzheimer's Disease Pathogenesis. Int J Mol Sci 2022; 23:ijms23169356. [PMID: 36012637 PMCID: PMC9409363 DOI: 10.3390/ijms23169356] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/10/2022] [Accepted: 08/18/2022] [Indexed: 01/02/2023] Open
Abstract
The main aim of this work is to review the mechanisms via which high-density lipoprotein (HDL)-mediated cholesterol trafficking through the central nervous system (CNS) occurs in the context of Alzheimer’s disease (AD). Alzheimer’s disease is characterized by the accumulation of extracellular amyloid beta (Aβ) and abnormally hyperphosphorylated intracellular tau filaments in neurons. Cholesterol metabolism has been extensively implicated in the pathogenesis of AD through biological, epidemiological, and genetic studies, with the APOE gene being the most reproducible genetic risk factor for the development of AD. This manuscript explores how HDL-mediated cholesterol is transported in the CNS, with a special emphasis on its relationship to Aβ peptide accumulation and apolipoprotein E (ApoE)-mediated cholesterol transport. Indeed, we reviewed all existing works exploring HDL-like-mediated cholesterol efflux and cholesterol uptake in the context of AD pathogenesis. Existing data seem to point in the direction of decreased cholesterol efflux and the impaired entry of cholesterol into neurons among patients with AD, which could be related to impaired Aβ clearance and tau protein accumulation. However, most of the reviewed studies have been performed in cells that are not physiologically relevant for CNS pathology, representing a major flaw in this field. The ApoE4 genotype seems to be a disruptive element in HDL-like-mediated cholesterol transport through the brain. Overall, further investigations are needed to clarify the role of cholesterol trafficking in AD pathogenesis.
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Affiliation(s)
- Carla Borràs
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- CIBERDEM, ISCIII, 28029 Madrid, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Aina Mercer
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
| | - Sònia Sirisi
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
| | - Daniel Alcolea
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
- CIBERNED, ISCIII, 28029 Madrid, Spain
| | - Joan Carles Escolà-Gil
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- CIBERDEM, ISCIII, 28029 Madrid, Spain
- Correspondence: (J.C.E.-G.); (M.T.); Tel.: +34-93-553-7358 (J.C.E.-G. & M.T.)
| | - Francisco Blanco-Vaca
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- CIBERDEM, ISCIII, 28029 Madrid, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
- Department of Biochemistry, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
| | - Mireia Tondo
- Institut d’Investigació Biomèdica Sant Pau (IIB), Sant Quintí 77-79, 08041 Barcelona, Spain
- CIBERDEM, ISCIII, 28029 Madrid, Spain
- Department of Biochemistry, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
- Correspondence: (J.C.E.-G.); (M.T.); Tel.: +34-93-553-7358 (J.C.E.-G. & M.T.)
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12
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Ho WY, Hartmann H, Ling SC. Central nervous system cholesterol metabolism in health and disease. IUBMB Life 2022; 74:826-841. [PMID: 35836360 DOI: 10.1002/iub.2662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/23/2022] [Indexed: 12/19/2022]
Abstract
Cholesterol is a ubiquitous and essential component of cellular membranes, as it regulates membrane structure and fluidity. Furthermore, cholesterol serves as a precursor for steroid hormones, oxysterol, and bile acids, that are essential for maintaining many of the body's metabolic processes. The biosynthesis and excretion of cholesterol is tightly regulated in order to maintain homeostasis. Although virtually all cells have the capacity to make cholesterol, the liver and brain are the two main organs producing cholesterol in mammals. Once produced, cholesterol is transported in the form of lipoprotein particles to other cell types and tissues. Upon formation of the blood-brain barrier (BBB) during embryonic development, lipoproteins cannot move between the central nervous system (CNS) and the rest of the body. As such, cholesterol biosynthesis and metabolism in the CNS operate autonomously without input from the circulation system in normal physiological conditions. Nevertheless, similar regulatory mechanisms for maintaining cholesterol homeostasis are utilized in both the CNS and peripheral systems. Here, we discuss the functions and metabolism of cholesterol in the CNS. We further focus on how different CNS cell types contribute to cholesterol metabolism, and how ApoE, the major CNS apolipoprotein, is involved in normal and pathophysiological functions. Understanding these basic mechanisms will aid our ability to elucidate how CNS cholesterol dysmetabolism contributes to neurogenerative diseases.
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Affiliation(s)
- Wan Y Ho
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Program in Neuroscience and Behavior Disorders, Duke-NUS Medical School, Singapore
| | - Hannelore Hartmann
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shuo-Chien Ling
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Program in Neuroscience and Behavior Disorders, Duke-NUS Medical School, Singapore.,Healthy Longevity Translational Research Programme, National University Health System, Singapore
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13
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α-Synuclein induced cholesterol lowering increases tonic and reduces depolarization-evoked synaptic vesicle recycling and glutamate release. NPJ Parkinsons Dis 2022; 8:71. [PMID: 35672421 PMCID: PMC9174203 DOI: 10.1038/s41531-022-00334-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 05/17/2022] [Indexed: 02/07/2023] Open
Abstract
α-Synuclein (α-syn) is a key molecule linked to Parkinson's disease pathology. Physiologically, the monomeric α-syn in the presynaptic termini is involved in regulation of neurotransmission, but the pathophysiology of extracellular monomeric α-syn is still unknown. Utilizing both in vivo and in vitro approaches, we investigated how extracellular α-syn impact presynaptic structure and function. Our data revealed that treatment with exogenous α-syn leads to increased tonic and decreased depolarization-evoked synaptic vesicle (SV) recycling and glutamate release. This was associated with mobilization of molecularly distinct SV pools and reorganization of active zone components. Our study also showed that exogenous α-syn impaired neuronal cholesterol level and that the cholesterol binding domain of α-syn was sufficient to exert the same presynaptic phenotype as the full-length protein. The present study sheds new light on physiological functions of extracellular α-syn in overall maintenance of presynaptic activity that involves the reorganization of both presynaptic compartment and cholesterol-rich plasma membrane domains.
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14
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Romo EZ, Zivkovic AM. Glycosylation of HDL-Associated Proteins and Its Implications in Cardiovascular Disease Diagnosis, Metabolism and Function. Front Cardiovasc Med 2022; 9:928566. [PMID: 35694676 PMCID: PMC9184513 DOI: 10.3389/fcvm.2022.928566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 01/09/2023] Open
Abstract
High-density lipoprotein (HDL) particles, long known for their critical role in the prevention of cardiovascular disease (CVD), were recently identified to carry a wide array of glycosylated proteins, and the importance of this glycosylation in the structure, function and metabolism of HDL are starting to emerge. Early studies have demonstrated differential glycosylation of HDL-associated proteins in various pathological states, which may be key to understanding their etiological role in these diseases and may be important for diagnostic development. Given the vast array and specificity of glycosylation pathways, the study of HDL-associated glycosylation has the potential to uncover novel mechanisms and biomarkers of CVD. To date, no large studies examining the relationships between HDL glycosylation profiles and cardiovascular outcomes have been performed. However, small pilot studies provide promising preliminary evidence that such a relationship may exist. In this review article we discuss the current state of the evidence on the glycosylation of HDL-associated proteins, the potential for HDL glycosylation profiling in CVD diagnostics, how glycosylation affects HDL function, and the potential for modifying the glycosylation of HDL-associated proteins to confer therapeutic value.
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15
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Lewandowski CT, Laham MS, Thatcher GR. Remembering your A, B, C's: Alzheimer's disease and ABCA1. Acta Pharm Sin B 2022; 12:995-1018. [PMID: 35530134 PMCID: PMC9072248 DOI: 10.1016/j.apsb.2022.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/27/2021] [Accepted: 01/07/2022] [Indexed: 12/24/2022] Open
Abstract
The function of ATP binding cassette protein A1 (ABCA1) is central to cholesterol mobilization. Reduced ABCA1 expression or activity is implicated in Alzheimer's disease (AD) and other disorders. Therapeutic approaches to boost ABCA1 activity have yet to be translated successfully to the clinic. The risk factors for AD development and progression, including comorbid disorders such as type 2 diabetes and cardiovascular disease, highlight the intersection of cholesterol transport and inflammation. Upregulation of ABCA1 can positively impact APOE lipidation, insulin sensitivity, peripheral vascular and blood–brain barrier integrity, and anti-inflammatory signaling. Various strategies towards ABCA1-boosting compounds have been described, with a bias toward nuclear hormone receptor (NHR) agonists. These agonists display beneficial preclinical effects; however, important side effects have limited development. In particular, ligands that bind liver X receptor (LXR), the primary NHR that controls ABCA1 expression, have shown positive effects in AD mouse models; however, lipogenesis and unwanted increases in triglyceride production are often observed. The longstanding approach, focusing on LXRβ vs. LXRα selectivity, is over-simplistic and has failed. Novel approaches such as phenotypic screening may lead to small molecule NHR modulators that elevate ABCA1 function without inducing lipogenesis and are clinically translatable.
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Raulin AC, Martens YA, Bu G. Lipoproteins in the Central Nervous System: From Biology to Pathobiology. Annu Rev Biochem 2022; 91:731-759. [PMID: 35303786 DOI: 10.1146/annurev-biochem-032620-104801] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The brain, as one of the most lipid-rich organs, heavily relies on lipid transport and distribution to maintain homeostasis and neuronal function. Lipid transport mediated by lipoprotein particles, which are complex structures composed of apolipoproteins and lipids, has been thoroughly characterized in the periphery. Although lipoproteins in the central nervous system (CNS) were reported over half a century ago, the identification of APOE4 as the strongest genetic risk factor for Alzheimer's disease has accelerated investigation of the biology and pathobiology of lipoproteins in the CNS. This review provides an overview of the different components of lipoprotein particles, in particular apolipoproteins, and their involvements in both physiological functions and pathological mechanisms in the CNS. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
| | - Yuka A Martens
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA;
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA;
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17
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Emerging role of HDL in brain cholesterol metabolism and neurodegenerative disorders. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159123. [PMID: 35151900 DOI: 10.1016/j.bbalip.2022.159123] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 01/07/2023]
Abstract
High-density lipoproteins (HDLs play a key role in cholesterol homeostasis maintenance in the central nervous system (CNS), by carrying newly synthesized cholesterol from astrocytes to neurons, to support their lipid-related physiological functions. As occurs for plasma HDLs, brain lipoproteins are assembled through the activity of membrane cholesterol transporters, undergo remodeling mediated by specific enzymes and transport proteins, and finally deliver cholesterol to neurons by a receptor-mediated internalization process. A growing number of evidences indicates a strong association between alterations of CNS cholesterol homeostasis and neurodegenerative disorders, in particular Alzheimer's disease (AD), and a possible role in this relationship may be played by defects in brain HDL metabolism. In the present review, we summarize and critically examine the current state of knowledge on major modifications of HDL and HDL-mediated brain cholesterol transport in AD, by taking into consideration the individual steps of this process. We also describe potential and encouraging HDL-based therapies that could represent new therapeutic strategies for AD treatment. Finally, we revise the main plasma and brain HDL modifications in other neurodegenerative disorders including Parkinson's disease (PD), Huntington's disease (HD), and frontotemporal dementia (FTD).
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18
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Pathophysiology of Lipid Droplets in Neuroglia. Antioxidants (Basel) 2021; 11:antiox11010022. [PMID: 35052526 PMCID: PMC8773017 DOI: 10.3390/antiox11010022] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 12/12/2022] Open
Abstract
In recent years, increasing evidence regarding the functional importance of lipid droplets (LDs), cytoplasmic storage organelles in the central nervous system (CNS), has emerged. Although not abundantly present in the CNS under normal conditions in adulthood, LDs accumulate in the CNS during development and aging, as well as in some neurologic disorders. LDs are actively involved in cellular lipid turnover and stress response. By regulating the storage of excess fatty acids, cholesterol, and ceramides in addition to their subsequent release in response to cell needs and/or environmental stressors, LDs are involved in energy production, in the synthesis of membranes and signaling molecules, and in the protection of cells against lipotoxicity and free radicals. Accumulation of LDs in the CNS appears predominantly in neuroglia (astrocytes, microglia, oligodendrocytes, ependymal cells), which provide trophic, metabolic, and immune support to neuronal networks. Here we review the most recent findings on the characteristics and functions of LDs in neuroglia, focusing on astrocytes, the key homeostasis-providing cells in the CNS. We discuss the molecular mechanisms affecting LD turnover in neuroglia under stress and how this may protect neural cell function. We also highlight the role (and potential contribution) of neuroglial LDs in aging and in neurologic disorders.
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19
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Azizidoost S, Babaahmadi-Rezaei H, Nazeri Z, Cheraghzadeh M, Kheirollah A. Amyloid beta increases ABCA1 and HMGCR protein expression, and cholesterol synthesis and accumulation in mice neurons and astrocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1867:159069. [PMID: 34744007 DOI: 10.1016/j.bbalip.2021.159069] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Imbalanced cholesterol metabolism in the brain is one of the main pathophysiological mechanisms involved in Alzheimer's disease. We investigated the effect of amyloid-beta (Aβ) on the main proteins involved in regulation of cholesterol metabolism along with cholesterol content in astrocytes and neurons. METHODS Astrocytes and neurons were cultured and treated with Aβ. Apolipoprotein E (apoE) level in the cells and conditioned media, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), ATP-binding cassette transporter A1 (ABCA1), and cytochrome P450 46A1 (CYP46A1) in cell lysates were determined using immunoblotting. Astrocyte media was added to the Aβ-pretreated neurons then, HMGCR was assessed. Cholesterol was measured in both cells and media. RESULTS Aβ caused a significant increase in HMGCR and ABCA1 protein levels and cholesterol content in both cells without increasing cholesterol efflux. A similar increase was seen for cellular apoE level in astrocytes with no changes in media with a significant reduction of cholesterol efflux. HMGCR level was restored to near control level when Aβ-pretreated neurons were exposed to media from culture astrocytes. CONCLUSION Almost all events related to cholesterol homeostasis in neurons and astrocytes, are somehow affected by Aβ. However, because ABCA1 has the most important role(s) in brain cholesterol homeostasis, all subsequent events associated with astrocytes-cholesterol synthesis and its shuttling to neurons are influenced by the effects of Aβ on ABCA1 which could likely be responsible for altered brain cholesterol metabolism in Alzheimer's disease.
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Affiliation(s)
- Shirin Azizidoost
- Atherosclerosis Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Hossein Babaahmadi-Rezaei
- Department of Biochemistry, Medical School, Cellular & Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Zahra Nazeri
- Department of Biochemistry, Medical School, Cellular & Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Maryam Cheraghzadeh
- Department of Biochemistry, Medical School, Cellular & Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Kheirollah
- Department of Biochemistry, Medical School, Cellular & Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
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20
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Cleland NRW, Al-Juboori SI, Dobrinskikh E, Bruce KD. Altered substrate metabolism in neurodegenerative disease: new insights from metabolic imaging. J Neuroinflammation 2021; 18:248. [PMID: 34711251 PMCID: PMC8555332 DOI: 10.1186/s12974-021-02305-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (NDs), such as Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS), are relatively common and devastating neurological disorders. For example, there are 6 million individuals living with AD in the United States, a number that is projected to grow to 14 million by the year 2030. Importantly, AD, PD and MS are all characterized by the lack of a true disease-modifying therapy that is able to reverse or halt disease progression. In addition, the existing standard of care for most NDs only addresses the symptoms of the disease. Therefore, alternative strategies that target mechanisms underlying the neuropathogenesis of disease are much needed. Recent studies have indicated that metabolic alterations in neurons and glia are commonly observed in AD, PD and MS and lead to changes in cell function that can either precede or protect against disease onset and progression. Specifically, single-cell RNAseq studies have shown that AD progression is tightly linked to the metabolic phenotype of microglia, the key immune effector cells of the brain. However, these analyses involve removing cells from their native environment and performing measurements in vitro, influencing metabolic status. Therefore, technical approaches that can accurately assess cell-specific metabolism in situ have the potential to be transformative to our understanding of the mechanisms driving AD. Here, we review our current understanding of metabolism in both neurons and glia during homeostasis and disease. We also evaluate recent advances in metabolic imaging, and discuss how emerging modalities, such as fluorescence lifetime imaging microscopy (FLIM) have the potential to determine how metabolic perturbations may drive the progression of NDs. Finally, we propose that the temporal, regional, and cell-specific characterization of brain metabolism afforded by FLIM will be a critical first step in the rational design of metabolism-focused interventions that delay or even prevent NDs.
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Affiliation(s)
- Nicholas R W Cleland
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
- School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Saif I Al-Juboori
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Kimberley D Bruce
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA.
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21
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Kloske CM, Dugan AJ, Weekman EM, Winder Z, Patel E, Nelson PT, Fardo DW, Wilcock DM. Inflammatory Pathways Are Impaired in Alzheimer Disease and Differentially Associated With Apolipoprotein E Status. J Neuropathol Exp Neurol 2021; 80:922-932. [PMID: 34486652 PMCID: PMC8557334 DOI: 10.1093/jnen/nlab085] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alzheimer disease (AD) is a neurodegenerative disease characterized by a cognitive decline leading to dementia. The most impactful genetic risk factor is apolipoprotein E (APOE). APOE-ε4 significantly increases AD risk, APOE-ε3 is the most common gene variant, and APOE-ε2 protects against AD. However, the underlying mechanisms of APOE-ε4 on AD risk remains unclear, with APOE-ε4 impacting many pathways. We investigated how the APOE isoforms associated with the neuroinflammatory state of the brain with and without AD pathology. Frozen brain tissue from the superior and middle temporal gyrus was analyzed from APOE-ε3/3 (n = 9) or APOE-ε4/4 (n = 10) participants with AD pathology and APOE-ε3/3 (n = 9) participants without AD pathology. We determined transcript levels of 757 inflammatory related genes using the NanoString Human Neuroinflammation Panel. We found significant pathways impaired in APOE-ε4/4-AD individuals compared to APOE-ε3/3-AD. Of interest, expression of genes related to microglial activation (SALL1), motility (FSCN1), epigenetics (DNMT1), and others showed altered expression. Additionally, we performed immunohistochemistry of P2RY12 to confirm reduced microglial activation. Our results suggest APOE-ε3 responds to AD pathology while potentially having a harmful long-term inflammatory response, while APOE-ε4 shows a weakened response to pathology. Overall, APOE isoforms appear to modulate the brain immune response to AD-type pathology.
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Affiliation(s)
- Courtney M Kloske
- From the Department of Physiology, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Adam J Dugan
- Department of Biostatistics, College of Public Health, University of Kentucky, Lexington, Kentucky, USA
| | - Erica M Weekman
- From the Department of Physiology, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Zachary Winder
- From the Department of Physiology, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Ela Patel
- Department of Pathology and Laboratory Medicine, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Peter T Nelson
- Department of Pathology and Laboratory Medicine, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - David W Fardo
- Department of Biostatics, Sanders-Brown Center on Aging, College of Public Health, University of Kentucky, Lexington, Kentucky, USA
| | - Donna M Wilcock
- From the Department of Physiology, Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
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22
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Koutsodendris N, Nelson MR, Rao A, Huang Y. Apolipoprotein E and Alzheimer's Disease: Findings, Hypotheses, and Potential Mechanisms. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2021; 17:73-99. [PMID: 34460318 DOI: 10.1146/annurev-pathmechdis-030421-112756] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder that involves dysregulation of many cellular and molecular processes. It is notoriously difficult to develop therapeutics for AD due to its complex nature. Nevertheless, recent advancements in imaging technology and the development of innovative experimental techniques have allowed researchers to perform in-depth analyses to uncover the pathogenic mechanisms of AD. An important consideration when studying late-onset AD is its major genetic risk factor, apolipoprotein E4 (apoE4). Although the exact mechanisms underlying apoE4 effects on AD initiation and progression are not fully understood, recent studies have revealed critical insights into the apoE4-induced deficits that occur in AD. In this review, we highlight notable studies that detail apoE4 effects on prominent AD pathologies, including amyloid-β, tau pathology, neuroinflammation, and neural network dysfunction. We also discuss evidence that defines the physiological functions of apoE and outlines how these functions are disrupted in apoE4-related AD. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Nicole Koutsodendris
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, California 94131, USA; , .,Gladstone Institutes of Neurological Disease, San Francisco, California 94158, USA
| | - Maxine R Nelson
- Gladstone Institutes of Neurological Disease, San Francisco, California 94158, USA.,Biomedical Sciences Graduate Program, University of California, San Francisco, California 94143, USA
| | - Antara Rao
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, California 94131, USA; , .,Gladstone Institutes of Neurological Disease, San Francisco, California 94158, USA
| | - Yadong Huang
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, California 94131, USA; , .,Gladstone Institutes of Neurological Disease, San Francisco, California 94158, USA.,Biomedical Sciences Graduate Program, University of California, San Francisco, California 94143, USA.,Department of Neurology, University of California, San Francisco, California 94158, USA
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23
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Yamauchi K, Kawakami Y. The redox status of cysteine thiol residues of apolipoprotein E impacts on its lipid interactions. Biol Chem 2021; 401:617-627. [PMID: 31913846 DOI: 10.1515/hsz-2019-0414] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/03/2020] [Indexed: 11/15/2022]
Abstract
Redox-mediated modulation of cysteine (Cys) thiols has roles in various pathophysiological functions. We recently found that formation of disulfide-linked complexes of apolipoprotein (apo) E3 prevented apoE3 from irreversible oxidation. In this report, the influence of modification of Cys thiols in apoE2 and apoE3 on interactions with lipids was investigated. The apoE redox status was examined by a band-shift assay using a maleimide compound, and interactions with lipids were evaluated by a kinetic assay using dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and non-denaturing polyacrylamide gel electrophoresis. A reduction in DMPC clearance activity of apoE2 and apoE3 but not apoE4 was observed. Although hydrogen peroxide-induced oxidation decreased the clearance activity of the isoforms, apoE2 showed the greatest residual activity. Both Cys thiol masking and dimerization decreased the activity of apoE2 and apoE3 but not apoE4. In contrast, apoAII preincubation markedly increased the activity (apoE2 > apoE3 > apoE4), in accordance with the formation of apoE-AII and apoAII-E2-AII complexes. ApoAII preincubation also reduced the particle size of apoE-DMPC liposome complexes, especially for apoE2. Redox-mediated modification of Cys thiols of apoE2 or apoE3, especially disulfide bond formation with apoAII, affects lipid metabolism and consequently may be responsible for the diverse isoform specificity of apoE.
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Affiliation(s)
- Kazuyoshi Yamauchi
- Department of Laboratory Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba305-8575, Japan
| | - Yasushi Kawakami
- Department of Laboratory Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba305-8575, Japan
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Nanjundaiah S, Chidambaram H, Chandrashekar M, Chinnathambi S. Role of Microglia in Regulating Cholesterol and Tau Pathology in Alzheimer's Disease. Cell Mol Neurobiol 2021; 41:651-668. [PMID: 32468440 DOI: 10.1007/s10571-020-00883-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 05/19/2020] [Indexed: 01/21/2023]
Abstract
Cholesterol, a principal constituent of the cell membrane, plays a crucial role in the brain by regulating the synaptic transmission, neuronal signaling, as well as neurodegenerative diseases. Defects in the cholesterol trafficking are associated with enhanced generation of hyperphosphorylated Tau and Amyloid-β protein. Tau, a major microtubule-associated protein in the brain, is the key regulator of the mature neuron. Abnormally hyperphosphorylated Tau hampers the major functions related to microtubule assembly by promoting neurofibrillary tangles of paired helical filaments, twisted ribbons, and straight filaments. The observed pathological changes due to impaired cholesterol and Tau protein accumulation cause Alzheimer's disease. Thus, in order to regulate the pathogenesis of Alzheimer's disease, regulation of cholesterol metabolism, as well as Tau phosphorylation, is essential. The current review provides an overview of (1) cholesterol synthesis in the brain, neurons, astrocytes, and microglia; (2) the mechanism involved in modulating cholesterol concentration between the astrocytes and brain; (3) major mechanisms involved in the hyperphosphorylation of Tau and amyloid-β protein; and (4) microglial involvement in its regulation. Thus, the answering key questions will provide an in-depth information on microglia involvement in managing the pathogenesis of cholesterol-modulated hyperphosphorylated Tau protein.
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Affiliation(s)
- Shwetha Nanjundaiah
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008, India
| | - Hariharakrishnan Chidambaram
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India
| | - Madhura Chandrashekar
- School of Biomedical Engineering and Sciences, MIT University, Loni Kalbhor, Pune, 412201, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India.
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25
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Lee JY, Marian OC, Don AS. Defective Lysosomal Lipid Catabolism as a Common Pathogenic Mechanism for Dementia. Neuromolecular Med 2021; 23:1-24. [PMID: 33550528 DOI: 10.1007/s12017-021-08644-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/11/2021] [Indexed: 02/06/2023]
Abstract
Dementia poses an ever-growing burden to health care and social services as life expectancies have grown across the world and populations age. The most common forms of dementia are Alzheimer's disease (AD), vascular dementia, frontotemporal dementia (FTD), and Lewy body dementia, which includes Parkinson's disease (PD) dementia and dementia with Lewy bodies (DLB). Genomic studies over the past 3 decades have identified variants in genes regulating lipid transporters and endosomal processes as major risk determinants for AD, with the most significant being inheritance of the ε4 allele of the APOE gene, encoding apolipoprotein E. A recent surge in research on lipid handling and metabolism in glia and neurons has established defective lipid clearance from endolysosomes as a central driver of AD pathogenesis. The most prevalent genetic risk factors for DLB are the APOE ε4 allele, and heterozygous loss of function mutations in the GBA gene, encoding the lysosomal catabolic enzyme glucocerebrosidase; whilst heterozygous mutations in the GRN gene, required for lysosomal catabolism of sphingolipids, are responsible for a significant proportion of FTD cases. Homozygous mutations in the GBA or GRN genes produce the lysosomal storage diseases Gaucher disease and neuronal ceroid lipofuscinosis. Research from mouse and cell culture models, and neuropathological evidence from lysosomal storage diseases, has established that impaired cholesterol or sphingolipid catabolism is sufficient to produce the pathological hallmarks of dementia, indicating that defective lipid catabolism is a common mechanism in the etiology of dementia.
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Affiliation(s)
- Jun Yup Lee
- Centenary Institute, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Oana C Marian
- Centenary Institute, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Anthony S Don
- Centenary Institute, The University of Sydney, Camperdown, NSW, 2006, Australia. .,NHMRC Clinical Trials Centre, The University of Sydney, Camperdown, NSW, 2006, Australia.
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26
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Marsillach J, Adorni MP, Zimetti F, Papotti B, Zuliani G, Cervellati C. HDL Proteome and Alzheimer's Disease: Evidence of a Link. Antioxidants (Basel) 2020; 9:E1224. [PMID: 33287338 PMCID: PMC7761753 DOI: 10.3390/antiox9121224] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 12/16/2022] Open
Abstract
Several lines of epidemiological evidence link increased levels of high-density lipoprotein-cholesterol (HDL-C) with lower risk of Alzheimer's disease (AD). This observed relationship might reflect the beneficial effects of HDL on the cardiovascular system, likely due to the implication of vascular dysregulation in AD development. The atheroprotective properties of this lipoprotein are mostly due to its proteome. In particular, apolipoprotein (Apo) A-I, E, and J and the antioxidant accessory protein paraoxonase 1 (PON1), are the main determinants of the biological function of HDL. Intriguingly, these HDL constituent proteins are also present in the brain, either from in situ expression, or derived from the periphery. Growing preclinical evidence suggests that these HDL proteins may prevent the aberrant changes in the brain that characterize AD pathogenesis. In the present review, we summarize and critically examine the current state of knowledge on the role of these atheroprotective HDL-associated proteins in AD pathogenesis and physiopathology.
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Affiliation(s)
- Judit Marsillach
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA;
| | - Maria Pia Adorni
- Unit of Neurosciences, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy;
| | - Francesca Zimetti
- Department of Food and Drug, University of Parma, 43124 Parma, Italy;
| | - Bianca Papotti
- Department of Food and Drug, University of Parma, 43124 Parma, Italy;
| | - Giovanni Zuliani
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, 44121 Ferrara, Italy; (G.Z.); (C.C.)
| | - Carlo Cervellati
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, 44121 Ferrara, Italy; (G.Z.); (C.C.)
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27
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ApoE Lipidation as a Therapeutic Target in Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21176336. [PMID: 32882843 PMCID: PMC7503657 DOI: 10.3390/ijms21176336] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 12/19/2022] Open
Abstract
Apolipoprotein E (APOE) is the major cholesterol carrier in the brain, affecting various normal cellular processes including neuronal growth, repair and remodeling of membranes, synaptogenesis, clearance and degradation of amyloid β (Aβ) and neuroinflammation. In humans, the APOE gene has three common allelic variants, termed E2, E3, and E4. APOE4 is considered the strongest genetic risk factor for Alzheimer’s disease (AD), whereas APOE2 is neuroprotective. To perform its normal functions, apoE must be secreted and properly lipidated, a process influenced by the structural differences associated with apoE isoforms. Here we highlight the importance of lipidated apoE as well as the APOE-lipidation targeted therapeutic approaches that have the potential to correct or prevent neurodegeneration. Many of these approaches have been validated using diverse cellular and animal models. Overall, there is great potential to improve the lipidated state of apoE with the goal of ameliorating APOE-associated central nervous system impairments.
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28
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Teresa JC, Fernado C, Nancy MR, Gilberto VA, Alberto CR, Roberto RR. Association of genetic variants of ABCA1 with susceptibility to dementia: (SADEM study). Metab Brain Dis 2020; 35:915-922. [PMID: 32447570 DOI: 10.1007/s11011-020-00577-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/29/2020] [Indexed: 10/24/2022]
Abstract
Because of the importance of cholesterol metabolism in the physiopathogenesis of dementia, and knowing the function of ATP-binding cassette A1 transporter (ABCA1) as a cholesterol flow pump at the cellular and cerebral level, it has been noted that the ABCA1 gene may be a good candidate for disease study. In order to evaluate the relationship between ABCA1 genetic variants and the risk of Alzheimer's disease and other dementia in Mexican individuals, we examined three ABCA1 polymorphisms located in the exonic region (rs2230808, rs2066718, rs2230806) and two in the promoter region (rs1800977, rs2422493) in a group of 557 normal controls and 221 cases of dementia. It was possible to distinguish one protective haplotype: CCCCGC (OR = 0,502, 95% CI = 0,370-0,681, p < 0.001), and one risk haplotype TCCCAT (OR = 2208, 95% CI = 1609-3031, p < 0.000) for the development of dementia. The results suggest that ABCA1 plays an important role in the pathophysiological mechanisms for the development of dementia.
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Affiliation(s)
- Juárez-Cedillo Teresa
- Unidad de Investigación Epidemiológica y en Servicios de Salud, Área Envejecimiento. Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (Actualmente comisionada en la Unidad de Investigación en Epidemiológica Clínica, Hospital General Regional Núm. 1 Dr. Carlos Mac Gregor Sánchez Navarro, Gabriel Mancera 222 esq. Xola. Colonia Del Valle. Delegación. Benito Juárez, IMSS), Mexico City, Mexico.
| | - Calzada Fernado
- Unidad de invetigación Médica en Farmacología UMAE, Hospital de Especialidades Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Martínez-Rodríguez Nancy
- Community Health Research. Department, Hospital Infantil de Mexico Federico Gomez, Ministry of Health (SSA), Mexico City, Mexico
| | - Vargas-Alarcón Gilberto
- Department of Molecular Biology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Cruz-Rocha Alberto
- Laboratorio de Urgencias del Hospital de Pediatría. Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Robles-Ramirez Roberto
- Laboratorio de Urgencias del Hospital de Pediatría. Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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29
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Kloske CM, Wilcock DM. The Important Interface Between Apolipoprotein E and Neuroinflammation in Alzheimer's Disease. Front Immunol 2020; 11:754. [PMID: 32425941 PMCID: PMC7203730 DOI: 10.3389/fimmu.2020.00754] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent form of neurodegenerative disease, currently affecting over 5 million Americans with projections expected to rise as the population ages. The hallmark pathologies of AD are Aβ plaques composed of aggregated beta-amyloid (Aβ), and tau tangles composed of hyperphosphorylated, aggregated tau. These pathologies are typically accompanied by an increase in neuroinflammation as an attempt to ameliorate the pathology. This idea has pushed the field toward focusing on mechanisms and the influence neuroinflammation has on disease progression. The vast majority of AD cases are sporadic and therefore, researchers investigate genetic risk factors that could lead to AD. Apolipoprotein E (ApoE) is the largest genetic risk factor for developing AD. ApoE has 3 isoforms-ApoE2, ApoE3, and ApoE4. ApoE4 constitutes an increased risk of AD, with one copy increasing the risk about 4-fold and two copies increasing the risk about 15-fold compared to those with the ApoE3 allele. ApoE4 has been shown to play a role in Aβ deposition, tau tangle formation, neuroinflammation and many subsequent pathways. However, while we know that ApoE4 plays a role in these pathways and virtually all aspects of AD, the exact mechanism of how ApoE4 impacts AD progression is murky at best and therefore the role ApoE4 plays in these pathways needs to be elucidated. This review aims to discuss the current literature regarding the pathways and mechanisms of ApoE4 in AD progression with a focus on its role in neuroinflammation.
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Affiliation(s)
- Courtney M Kloske
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Donna M Wilcock
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
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30
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Idriss AA, Hu Y, Sun Q, Hou Z, Yang S, Omer NA, Abobaker H, Zhao R. Fetal betaine exposure modulates hypothalamic expression of cholesterol metabolic genes in offspring cockerels with modification of promoter DNA methylation. Poult Sci 2020; 99:2533-2542. [PMID: 32359589 PMCID: PMC7597399 DOI: 10.1016/j.psj.2019.12.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/30/2019] [Accepted: 12/02/2019] [Indexed: 12/28/2022] Open
Abstract
In documents, maternal betaine modulates hypothalamic cholesterol metabolism in chicken posthatchings, but it remains unclear whether this effect can be passed on by generations. In present study, eggs were injected with saline or betaine at 2.5 mg/egg, and the hatchlings (F1) were raised under the same condition until sexual maturation. Both the control group and the betaine group used artificial insemination to collect sperm from their cockerels. Fertilized eggs were incubated, and the hatchlings of the following generation (F2) were raised up to 64 D of age. F2 cockerels in betaine group showed significantly (P < 0.05) lower body weight, which was associated with significantly decreased (P < 0.05) hypothalamic content of total cholesterol and cholesterol ester. Concordantly, hypothalamic expression of cholesterol biosynthetic genes, SREBP2 and HMGCR, were significantly downregulated (P < 0.05), together with cholesterol conversion-related and excretion-related genes, CYP46A1 and ABCA1. These changes coincided with a significant downregulation in mRNA expression of regulatory neuropeptides including brain-derived neurotrophic factor, neuropeptide Y, and corticotropin-releasing hormone. Moreover, genes involved in methyl transfer cycle were also modified. Betaine homocysteine methyltransferase (P < 0.05) was downregulated, yet DNA methyltransferase1 tended to be upregulated (P = 0.06). S-adenosyl methionine/S-adenosylhomocysteine ratio was higher in the hypothalamus of betaine-treated F2 cockerels, which was associated with significantly modified CpG methylation on the promoter of those affected genes. These results suggested that betaine might regulate central cholesterol metabolism and hypothalamic expression of genes related to brain function by altering promoter DNA methylation in F2 cockerels.
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Affiliation(s)
- Abdulrahman A Idriss
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Yun Hu
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Qinwei Sun
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China.
| | - Zhen Hou
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Shu Yang
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Nagmeldin A Omer
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Halima Abobaker
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Ruqian Zhao
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China; Jiangsu Collaborative Innovation Centre of Meat Production and Processing, Quality and Safety Control, Nanjing 210095, P. R. China
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31
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APOE in the normal brain. Neurobiol Dis 2020; 136:104724. [PMID: 31911114 DOI: 10.1016/j.nbd.2019.104724] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/19/2019] [Accepted: 12/31/2019] [Indexed: 12/25/2022] Open
Abstract
The APOE4 protein affects the primary neuropathological markers of Alzheimer's disease (AD): amyloid plaques, neurofibrillary tangles, and gliosis. These interactions have been investigated to understand the strong effect of APOE genotype on risk of AD. However, APOE genotype has strong effects on processes in normal brains, in the absence of the hallmarks of AD. We propose that CNS APOE is involved in processes in the normal brains that in later years apply specifically to processes of AD pathogenesis. We review the differences of the APOE protein found in the CNS compared to the plasma, including post-translational modifications (glycosylation, lipidation, multimer formation), focusing on ways that the common APOE isoforms differ from each other. We also review structural and functional studies of young human brains and control APOE knock-in mouse brains. These approaches demonstrate the effects of APOE genotype on microscopic neuron structure, gross brain structure, and behavior, primarily related to the hippocampal areas. By focusing on the effects of APOE genotype on normal brain function, approaches can be pursued to identify biomarkers of APOE dysfunction, to promote normal functions of the APOE4 isoform, and to prevent the accumulation of the pathologic hallmarks of AD with aging.
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32
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Patra K, Giannisis A, Edlund AK, Sando SB, Lauridsen C, Berge G, Grøntvedt GR, Bråthen G, White LR, Nielsen HM. Plasma Apolipoprotein E Monomer and Dimer Profile and Relevance to Alzheimer's Disease. J Alzheimers Dis 2019; 71:1217-1231. [PMID: 31524156 DOI: 10.3233/jad-190175] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The APOEɛ4 gene variant is the strongest genetic risk factor for Alzheimer's disease (AD), whereas APOEɛ3 conventionally is considered as 'risk neutral' although APOEɛ3-carriers also develop AD. Previous studies have shown that the apolipoprotein E3 (apoE3) isoform occurs as monomers, homodimers and heterodimers with apolipoprotein A-II in human body fluids and brain tissue, but the relevance of a plasma apoE3 monomer/dimer profile to AD is unknown. Here we assessed the distribution of monomers, homodimers and heterodimers in plasma from control subjects and patients with mild cognitive impairment (MCI) and AD with either a homozygous APOEɛ3 (n = 31 control subjects, and n = 14 MCI versus n = 5 AD patients) or APOEɛ4 genotype (n = 1 control subject, n = 21 MCI and n = 7 AD patients). Total plasma apoE levels were lower in APOEɛ4-carriers and overall correlated significantly to CSF Aβ42, p(Thr181)-tau and t-tau levels. Apolipoprotein E dimers were only observed in the APOEɛ3-carriers and associated with total plasma apoE levels, negatively correlated to apoE monomers, but were unrelated to plasma homocysteine levels. Importantly, the APOEɛ3-carrying AD patients versus controls exhibited a significant decrease in apoE homodimers (17.8±9.6% versus 26.7±6.3%, p = 0.025) paralleled by an increase in apoE monomers (67.8±18.3% versus 48.5±11.2%, p = 0.008). In the controls, apoE monomers and heterodimers were significantly associated with plasma triglycerides; the apoE heterodimers were also associated with levels of high-density lipoprotein cholesterol. The physiological relevance of apoE dimer formation needs to be further investigated, though the distribution of apoE in monomers and dimers appears to be of relevance to AD in APOEɛ3 subjects.
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Affiliation(s)
- Kalicharan Patra
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Andreas Giannisis
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Anna K Edlund
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Sigrid Botne Sando
- Department of Neurology, University Hospital of Trondheim, Trondheim, Norway.,Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Camilla Lauridsen
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Guro Berge
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Geir Bråthen
- Department of Neurology, University Hospital of Trondheim, Trondheim, Norway.,Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Linda R White
- Department of Neurology, University Hospital of Trondheim, Trondheim, Norway.,Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Henrietta M Nielsen
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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33
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Marchi C, Adorni MP, Caffarra P, Ronda N, Spallazzi M, Barocco F, Galimberti D, Bernini F, Zimetti F. ABCA1- and ABCG1-mediated cholesterol efflux capacity of cerebrospinal fluid is impaired in Alzheimer's disease. J Lipid Res 2019; 60:1449-1456. [PMID: 31167810 DOI: 10.1194/jlr.p091033] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 05/25/2019] [Indexed: 01/18/2023] Open
Abstract
HDL-like particles in human cerebrospinal fluid (CSF) promote the efflux of cholesterol from astrocytes toward the neurons that rely on this supply for their functions. We evaluated whether cell cholesterol efflux capacity of CSF (CSF-CEC) is impaired in Alzheimer's disease (AD) by analyzing AD (n = 37) patients, non-AD dementia (non-AD DEM; n = 16) patients, and control subjects (n = 39). As expected, AD patients showed reduced CSF Aβ 1-42, increased total and phosphorylated tau, and a higher frequency of the apoε4 genotype. ABCA1- and ABCG1-mediated CSF-CEC was markedly reduced in AD (-73% and -33%, respectively) but not in non-AD DEM patients, in which a reduced passive diffusion CEC (-40%) was observed. Non-AD DEM patients displayed lower CSF apoE concentrations (-24%) compared with controls, while apoA-I levels were similar among groups. No differences in CSF-CEC were found by stratifying subjects for apoε4 status. ABCG1 CSF-CEC positively correlated with Aβ 1-42 (r = 0.305, P = 0.025), while ABCA1 CSF-CEC inversely correlated with total and phosphorylated tau (r = -0.348, P = 0.018 and r = -0.294, P = 0.048, respectively). The CSF-CEC impairment and the correlation with the neurobiochemical markers suggest a pathophysiological link between CSF HDL-like particle dysfunction and neurodegeneration in AD.
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Affiliation(s)
- Cinzia Marchi
- Department of Food and Drug University of Parma, Parma, Italy
| | | | - Paolo Caffarra
- Department of Medicine and Surgery, Section of Neurology University of Parma, Parma, Italy.,Alzheimer Center Briolini Hospital, Gazzaniga, Bergamo, Italy
| | - Nicoletta Ronda
- Department of Food and Drug University of Parma, Parma, Italy
| | - Marco Spallazzi
- Department of Medicine and Surgery, Section of Neurology University of Parma, Parma, Italy
| | - Federica Barocco
- Department of Medicine and Surgery, Section of Neurology University of Parma, Parma, Italy
| | - Daniela Galimberti
- Department of Biomedical, Surgical and Dental Sciences, Dino Ferrari Center, University of Milano, Milano, Italy.,Neurodegenerative Diseases Unit Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milano, Italy
| | - Franco Bernini
- Department of Food and Drug University of Parma, Parma, Italy
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34
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Redox equilibrium of serum apolipoprotein E3: a buffering effect of disulfide-linked complexes against oxidative stress on apolipoprotein E3-containing lipoproteins. Biosci Rep 2019; 39:BSR20190184. [PMID: 30948502 PMCID: PMC6488860 DOI: 10.1042/bsr20190184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/24/2019] [Accepted: 04/03/2019] [Indexed: 11/17/2022] Open
Abstract
Reversible redox modification of cysteine thiols is crucial for protecting proteins from irreversible detrimental change. However, the physiological significance of the redox modification of apolipoprotein (apo) E is unclear. Here, we hypothesized that the disulfide-linked complexes of apoE3 corresponding to the representative reversible-modified apoE3 play a protective role against oxidative stress. The effects of disulfide bond formation on oxidative stress on apoE3 were evaluated with a band-shift assay. Maleimide-labeled apoE3 and unlabeled apoE3 were defined as the reduced (r)-apoE3 and non-reduced (nr)-apoE3 forms, respectively. Hydrogen peroxide-induced oxidation decreased for reduced-form apoE (r-apoE3) but increased for nr-apoE3. Induction of apoE3-AII complex formation with excess of apoAII markedly suppressed the oxidative stress-induced increase in nr-apoE3 (P<0.001) and enhanced homodimer formation. The apoE3-AII complex was more dominant in high-density lipoprotein (HDL) than in very low-density lipoprotein. Under oxidative stress, HDL showed a significant decrease, rather than an increase, in nr-apoE3 levels with a concomitant significant increase in apoE3-AII levels (P<0.005). This finding suggests that the majority of nr-apoE3 in HDL exists in a reversible oxidized form. The apoE3-AII complex, formed from the reversible oxidized apoE3, is beneficial for maintaining the redox equilibrium of apoE3 by preventing the modification of apoE3 to its irreversible oxidized form. The apoE3-AII complex may be possibly implicated in the pathophysiology of various apoE-related diseases.
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35
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van der Kant R, Langness VF, Herrera CM, Williams DA, Fong LK, Leestemaker Y, Steenvoorden E, Rynearson KD, Brouwers JF, Helms JB, Ovaa H, Giera M, Wagner SL, Bang AG, Goldstein LSB. Cholesterol Metabolism Is a Druggable Axis that Independently Regulates Tau and Amyloid-β in iPSC-Derived Alzheimer's Disease Neurons. Cell Stem Cell 2019; 24:363-375.e9. [PMID: 30686764 PMCID: PMC6414424 DOI: 10.1016/j.stem.2018.12.013] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 09/26/2018] [Accepted: 12/17/2018] [Indexed: 02/07/2023]
Abstract
Genetic, epidemiologic, and biochemical evidence suggests that predisposition to Alzheimer's disease (AD) may arise from altered cholesterol metabolism, although the molecular pathways that may link cholesterol to AD phenotypes are only partially understood. Here, we perform a phenotypic screen for pTau accumulation in AD-patient iPSC-derived neurons and identify cholesteryl esters (CE), the storage product of excess cholesterol, as upstream regulators of Tau early during AD development. Using isogenic induced pluripotent stem cell (iPSC) lines carrying mutations in the cholesterol-binding domain of APP or APP null alleles, we found that while CE also regulate Aβ secretion, the effects of CE on Tau and Aβ are mediated by independent pathways. Efficacy and toxicity screening in iPSC-derived astrocytes and neurons showed that allosteric activation of CYP46A1 lowers CE specifically in neurons and is well tolerated by astrocytes. These data reveal that CE independently regulate Tau and Aβ and identify a druggable CYP46A1-CE-Tau axis in AD.
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Affiliation(s)
- Rik van der Kant
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands
| | - Vanessa F Langness
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cheryl M Herrera
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Daniel A Williams
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lauren K Fong
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yves Leestemaker
- Oncode Institute and Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Evelyne Steenvoorden
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Kevin D Rynearson
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jos F Brouwers
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University Yalelaan 2, 3584 CM Utrecht, the Netherlands
| | - J Bernd Helms
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University Yalelaan 2, 3584 CM Utrecht, the Netherlands
| | - Huib Ovaa
- Oncode Institute and Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Steven L Wagner
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA; Research Biologist, VA San Diego Healthcare System, La Jolla, CA 92161, USA
| | - Anne G Bang
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA.
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Mise A, Yoshino Y, Yamazaki K, Ozaki Y, Sao T, Yoshida T, Mori T, Mori Y, Ochi S, Iga JI, Ueno SI. TOMM40 and APOE Gene Expression and Cognitive Decline in Japanese Alzheimer's Disease Subjects. J Alzheimers Dis 2018; 60:1107-1117. [PMID: 28984592 DOI: 10.3233/jad-170361] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND TOMM40 is located on chromosome 19, is in linkage disequilibrium with apolipoprotein E (APOE), andis reported in several genome-wide association studies to be associated with Alzheimer's disease (AD). OBJECTIVE Assess APOE and TOM40 and mitochondrial genes as blood biomarkers for AD. METHODS We examined TOMM40, PTEN-induced putative kinase 1 (PINK1), Parkin RBR E3 ubiquitin protein ligase (PARK2), and APOE mRNA expression in relation to the methylation rates of CpG sites in the upstream region of TOMM40exon 1 in peripheral leukocytes and TOMM40523 polyT genotypes in 60 AD and age- and sex-matched control subjects. RESULTS TOMM40 mRNA expression was significantly lower in AD subjects (0.87±0.18 versus 1.0±0.23, p = 0.005), and PINK1 mRNA expression was higher in AD subjects (1.5±0.61 versus 1.0±0.52, p < 0.001). TOMM40 mRNA expression was significantly correlated with the Mini-Mental State Examination total score (r = 0.290, p = 0.027). There was no expressional change in peripheral APOE mRNA in either AD or control subjects (p = 0.32). Methylation rates in the upstream region of TOMM40exon 1 were not different between AD and control subjects (average rate: 1.37±0.99 versus 1.39±1.20, p = 0.885), and TOMM40523 polyT genotypes were also not different between AD and control subjects (p = 0.67). CONCLUSION TOMM40 mRNA expression was lower in AD subjects and was correlated with cognitive decline. Significant changes in both TOMM40 and PINK1 mRNA may be related to mitochondrial dysfunction.
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Affiliation(s)
- Ayano Mise
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Yuta Yoshino
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Kiyohiro Yamazaki
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Yuki Ozaki
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Tomoko Sao
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Taku Yoshida
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Takaaki Mori
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Yoko Mori
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Shinichiro Ochi
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Jun-Ichi Iga
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Shu-Ichi Ueno
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
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Petty HR. Frontiers of Complex Disease Mechanisms: Membrane Surface Tension May Link Genotype to Phenotype in Glaucoma. Front Cell Dev Biol 2018; 6:32. [PMID: 29682502 PMCID: PMC5897435 DOI: 10.3389/fcell.2018.00032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/13/2018] [Indexed: 12/19/2022] Open
Abstract
Although many monogenic diseases are understood based upon structural changes of gene products, less progress has been made concerning polygenic disease mechanisms. This article presents a new interdisciplinary approach to understand complex diseases, especially their genetic polymorphisms. I focus upon primary open angle glaucoma (POAG). Although elevated intraocular pressure (IOP) and oxidative stress are glaucoma hallmarks, the linkages between these factors and cell death are obscure. Reactive oxygen species (ROS) promote the formation of oxidatively truncated phosphoglycerides (OTP), free fatty acids, lysophosphoglycerides, oxysterols, and other chemical species that promote membrane disruption and decrease membrane surface tension. Several POAG-linked gene polymorphisms identify proteins that manage damaged lipids and/or influence membrane surface tension. POAG-related genes expected to participate in these processes include: ELOVL5, ABCA1, APOE4, GST, CYP46A1, MYOC, and CAV. POAG-related gene products are expected to influence membrane surface tension, strength, and repair. I propose that heightened IOP overcomes retinal ganglion cell (RGC) membrane compressive strength, weakened by damaged lipid accumulation, to form pores. The ensuing structural failure promotes apoptosis and blindness. The linkage between glaucoma genotype and phenotype is mediated by physical events. Force balancing between the IOP and compressive strength regulates pore nucleation; force balancing between pore line tension and membrane surface tension regulates pore growth. Similar events may contribute to traumatic brain injury, Alzheimer's disease, and macular degeneration.
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Affiliation(s)
- Howard R Petty
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, Ann Arbor, MI, United States
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Boehm-Cagan A, Bar R, Liraz O, Bielicki JK, Johansson JO, Michaelson DM. ABCA1 Agonist Reverses the ApoE4-Driven Cognitive and Brain Pathologies. J Alzheimers Dis 2018; 54:1219-1233. [PMID: 27567858 DOI: 10.3233/jad-160467] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The allele ɛ4 of apolipoprotein E (apoE4) is the most prevalent genetic risk factor for Alzheimer's disease (AD) and is therefore a promising therapeutic target. Human and animal model studies suggest that apoE4 is hypolipidated; accordingly, we have previously shown that the retinoid X receptor (RXR) agonist bexarotene upregulates ABCA1, the main apoE-lipidating protein, resulting in increased lipidation of apoE4, and the subsequent reversal of the pathological effects of apoE4, namely: accumulation of Aβ42 and hyperphosphorylated tau, as well as reduction in the levels of synaptic markers and cognitive deficits. Since the RXR system has numerous other targets, it is important to devise the means of activating ABCA1 selectively. We presently utilized CS-6253, a peptide shown to directly activate ABCA1 in vitro, and examined the extent to which it can affect the degree of lipidation of apoE4 in vivo and counteract the associated brain and behavioral pathologies. This revealed that treatment of young apoE4-targeted replacement mice with CS-6253 increases the lipidation of apoE4. This was associated with a reversal of the apoE4-driven Aβ42 accumulation and tau hyperphosphorylation in hippocampal neurons, as well as of the synaptic impairments and cognitive deficits. These findings suggest that the pathological effects of apoE4 in vivo are associated with decreased activation of ABCA1 and impaired lipidation of apoE4 and that the downstream brain-related pathology and cognitive deficits can be counteracted by treatment with the ABCA1 agonist CS-6253. These findings have important clinical ramifications and put forward ABCA1 as a promising target for apoE4-related treatment of AD.
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Affiliation(s)
- Anat Boehm-Cagan
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Roni Bar
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Ori Liraz
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - John K Bielicki
- Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, USA
| | | | - Daniel M Michaelson
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Tomioka M, Toda Y, Mañucat NB, Akatsu H, Fukumoto M, Kono N, Arai H, Kioka N, Ueda K. Lysophosphatidylcholine export by human ABCA7. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:658-665. [PMID: 28373057 DOI: 10.1016/j.bbalip.2017.03.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 03/27/2017] [Accepted: 03/29/2017] [Indexed: 10/19/2022]
Abstract
The ATP-binding cassette transporter A7 (ABCA7), which is highly expressed in the brain, is associated with the pathogenesis of Alzheimer's disease (AD). However, the physiological function of ABCA7 and its transport substrates remain unclear. Immunohistochemical analyses of human brain sections from AD and non-AD subjects revealed that ABCA7 is expressed in neuron and microglia cells in the cerebral cortex. The transport substrates and acceptors were identified in BHK/ABCA7 cells and compared with those of ABCA1. Like ABCA1, ABCA7 exported choline phospholipids in the presence of apoA-I and apoE; however, unlike ABCA1, cholesterol efflux was marginal. Lipid efflux by ABCA7 was saturated by 5μg/ml apoA-I and was not dependent on apoE isoforms, whereas efflux by ABCA1 was dependent on apoA-I up to 20μg/ml and apoE isoforms. Liquid chromatography-tandem mass spectrometry analyses revealed that the two proteins had different preferences for phospholipid export: ABCA7 preferred phosphatidylcholine (PC)≥lysoPC>sphingomyelin (SM)=phosphatidylethanolamine (PE), whereas ABCA1 preferred PC>>SM>PE=lysoPC. The major difference in the pattern of lipid peaks between ABCA7 and ABCA1 was the high lysoPC/PC ratio of ABCA7. These results suggest that lysoPC is one of the major transport substrates for ABCA7 and that lysoPC export may be a physiologically important function of ABCA7 in the brain.
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Affiliation(s)
- Maiko Tomioka
- Institute for integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8502, Japan
| | - Yoshinobu Toda
- Faculty of Health Care, Tenri Health Care University, Tenri, Nara 632-0018, Japan.
| | - Noralyn B Mañucat
- Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroyasu Akatsu
- Graduate School of Medical Sciences and Medical School, Nagoya City University, Nagoya 467-8601, Japan
| | - Manabu Fukumoto
- Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan
| | - Nozomu Kono
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroyuki Arai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Noriyuki Kioka
- Institute for integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8502, Japan; Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Kazumitsu Ueda
- Institute for integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8502, Japan; Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
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Yamauchi K, Ebihara Y, Kawakami Y. Redox status of serum apolipoprotein E and its impact on HDL cholesterol levels. Clin Biochem 2017; 50:777-783. [PMID: 28366823 DOI: 10.1016/j.clinbiochem.2017.03.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 02/27/2017] [Accepted: 03/24/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND Apolipoprotein E (apoE) is closely involved in the pathogenesis of apoE-related diseases, such as Alzheimer's disease and cardiovascular disease. The redox modulation of cysteine-thiols in a protein is involved in various pathophysiological regulations; however, that of apoE has not been studied in detail. Herein, we devised an analytical method to determine the redox status of serum apoE and assessed its relation to serum cholesterol levels and apoE phenotype. METHODS The present method was based on a band shift assay, using a photocleavable maleimide-conjugated polyethylene glycol. RESULTS The basic characteristics of the present method were found to be satisfactory to determine the redox status of serum apoE quantitatively. Serum apoE was separated into its reduced-form (r-), non-reduced-form (nr-), apoE-AII complex, and homodimer using this method. R-apoE could be detected as a 40-kDa band, whereas nr-apoE remained as monomeric apoE. R-apoE displayed a preference for VLDL; however, the levels showed the correlation with HDL-cholesterol levels (p<0.005). Redox status of serum apoE was significantly different among apoE phenotypes. The quantitative ratios of nr-apoE to total apoE in serum from subjects with apoE4/E3 were higher than in serum from subjects with apoE3/E3 (p<0.0001) and apoE3/E2 (p<0.001). CONCLUSION The redox status of serum apoE might be related to the synthesis of HDL. The information concerning the redox status of serum apoE provided by the present method may be a potent indicator to evaluate various apoE-related diseases.
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Affiliation(s)
- Kazuyoshi Yamauchi
- Department of Laboratory Medicine, Faculty of Medicine, University of Tsukuba, Japan; Department of Medical Sciences, Faculty of Medicine, University of Tsukuba, Japan.
| | - Yuka Ebihara
- Department of Medical Sciences, Faculty of Medicine, University of Tsukuba, Japan
| | - Yasushi Kawakami
- Department of Laboratory Medicine, Faculty of Medicine, University of Tsukuba, Japan
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Chang TY, Yamauchi Y, Hasan MT, Chang C. Cellular cholesterol homeostasis and Alzheimer's disease. J Lipid Res 2017; 58:2239-2254. [PMID: 28298292 DOI: 10.1194/jlr.r075630] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in older adults. Currently, there is no cure for AD. The hallmark of AD is the accumulation of extracellular amyloid plaques composed of amyloid-β (Aβ) peptides (especially Aβ1-42) and neurofibrillary tangles, composed of hyperphosphorylated tau and accompanied by chronic neuroinflammation. Aβ peptides are derived from the amyloid precursor protein (APP). The oligomeric form of Aβ peptides is probably the most neurotoxic species; its accumulation eventually forms the insoluble and aggregated amyloid plaques. ApoE is the major apolipoprotein of the lipoprotein(s) present in the CNS. ApoE has three alleles, of which the Apoe4 allele constitutes the major risk factor for late-onset AD. Here we describe the complex relationship between ApoE4, oligomeric Aβ peptides, and cholesterol homeostasis. The review consists of four parts: 1) key elements involved in cellular cholesterol metabolism and regulation; 2) key elements involved in intracellular cholesterol trafficking; 3) links between ApoE4, Aβ peptides, and disturbance of cholesterol homeostasis in the CNS; 4) potential lipid-based therapeutic targets to treat AD. At the end, we recommend several research topics that we believe would help in better understanding the connection between cholesterol and AD for further investigations.
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Affiliation(s)
- Ta-Yuan Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Mazahir T Hasan
- Laboratory of Memory Circuits, Achucarro Basque Center for Neuroscience, Zamudio, Spain
| | - Catherine Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
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Rebeck GW. The role of APOE on lipid homeostasis and inflammation in normal brains. J Lipid Res 2017; 58:1493-1499. [PMID: 28258087 DOI: 10.1194/jlr.r075408] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/02/2017] [Indexed: 12/24/2022] Open
Abstract
The role of APOE in the risk of Alzheimer's disease (AD) has largely focused on its effects on AD pathological processes. However, there are increasing data that APOE genotype affects processes in normal brains. Studies of young cognitively normal humans show effects of APOE genotype on brain structure and activity. Studies of normal APOE knock-in mice show effects of APOE genotype on brain structure, neuronal markers, and behavior. APOE interactions with molecules important for lipid efflux and lipid endocytosis underlie effects of APOE genotype on neuroinflammation and lipoprotein composition. These effects provide important targets for new therapies for reduction of the risk of AD before any signs of pathogenesis.
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Affiliation(s)
- G William Rebeck
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC.
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Boehm-Cagan A, Bar R, Harats D, Shaish A, Levkovitz H, Bielicki JK, Johansson JO, Michaelson DM. Differential Effects of apoE4 and Activation of ABCA1 on Brain and Plasma Lipoproteins. PLoS One 2016; 11:e0166195. [PMID: 27824936 PMCID: PMC5100931 DOI: 10.1371/journal.pone.0166195] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/24/2016] [Indexed: 01/28/2023] Open
Abstract
Apolipoprotein E4 (apoE4), the leading genetic risk factor for Alzheimer's disease (AD), is less lipidated compared to the most common and AD-benign allele, apoE3. We have recently shown that i.p. injections of the ATP-binding cassette A1 (ABCA1) agonist peptide CS-6253 to apoE mice reverse the hypolipidation of apoE4 and the associated brain pathology and behavioral deficits. While in the brain apoE is the main cholesterol transporter, in the periphery apoE and apoA-I both serve as the major cholesterol transporters. We presently investigated the extent to which apoE genotype and CS-6253 treatment to apoE3 and apoE4-targeted replacement mice affects the plasma levels and lipid particle distribution of apoE, and those of plasma and brain apoA-I and apoJ. This revealed that plasma levels of apoE4 were lower and eluted faster following FPLC than plasma apoE3. Treatment with CS-6253 increased the levels of plasma apoE4 and rendered the elution profile of apoE4 similar to that of apoE3. Similarly, the levels of plasma apoA-I were lower in the apoE4 mice compared to apoE3 mice, and this effect was partially reversed by CS-6253. Conversely, the levels of apoA-I in the brain which were higher in the apoE4 mice, were unaffected by CS-6253. The plasma levels of apoJ were higher in apoE4 mice than apoE3 mice and this effect was abolished by CS-6253. Similar but less pronounced effects were obtained in the brain. In conclusion, these results suggest that apoE4 affects the levels of apoA-I and apoJ and that the anti-apoE4 beneficial effects of CS-6253 may be related to both central and peripheral mechanisms.
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Affiliation(s)
- Anat Boehm-Cagan
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Roni Bar
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Dror Harats
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
- The Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel-Hashomer 5265601, Israel
| | - Aviv Shaish
- The Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel-Hashomer 5265601, Israel
| | - Hana Levkovitz
- The Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel-Hashomer 5265601, Israel
| | - John K. Bielicki
- Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California, 94720, United States of America
| | - Jan O. Johansson
- Artery Therapeutics, Inc. San Ramon, California, United States of America
| | - Daniel M. Michaelson
- The Department of Neurobiology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
- * E-mail:
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Heinsinger NM, Gachechiladze MA, Rebeck GW. Apolipoprotein E Genotype Affects Size of ApoE Complexes in Cerebrospinal Fluid. J Neuropathol Exp Neurol 2016; 75:918-924. [PMID: 27516118 DOI: 10.1093/jnen/nlw067] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Apolipoprotein E (apoE) is associated with lipoproteins in the cerebrospinal fluid (CSF). APOE4 increases and APOE2 decreases the risk for Alzheimer disease (AD) compared to the risk associated with APOE3 Because apoE4 is less efficient at cholesterol efflux than apoE2 or apoE3 in vitro, we hypothesized that APOE genotype may affect apoE particle size in vivo and that these size differences may be related to AD risk. We used nondenaturing gel electrophoresis to test for differences in the size of apoE complexes in human CSF samples of various APOE genotypes and created profiles of each sample to compare the patterns of apoE distribution. For middle-aged adults with no dementia, APOE 2.3 individuals had significantly larger apoE complexes than APOE 3.3 subjects, who had significantly larger apoE complexes than APOE 3.4 and APOE 4.4 individuals. Similarly, in an independent cohort of older adults, CSF apoE complexes of APOE4-positive individuals were smaller than those of the APOE4-negative individuals. Compared to individuals with no dementia, those with the mildest stages of dementia had similar sized CSF apoE complexes. These results identify a novel phenotypic difference in the size of CSF apoE complexes in middle age that correlate with the risk of AD later in life.
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Affiliation(s)
- Nicolette Mary Heinsinger
- From the Department of Biology (NMH, MAG); and Department of Neuroscience, Georgetown University (GWR), Washington, District of Columbia
| | - Mariam Alexandra Gachechiladze
- From the Department of Biology (NMH, MAG); and Department of Neuroscience, Georgetown University (GWR), Washington, District of Columbia
| | - G William Rebeck
- From the Department of Biology (NMH, MAG); and Department of Neuroscience, Georgetown University (GWR), Washington, District of Columbia
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Abstract
Cholesterol is an essential component for neuronal physiology not only during development stage but also in the adult life. Cholesterol metabolism in brain is independent from that in peripheral tissues due to blood-brain barrier. The content of cholesterol in brain must be accurately maintained in order to keep brain function well. Defects in brain cholesterol metabolism has been shown to be implicated in neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), and some cognitive deficits typical of the old age. The brain contains large amount of cholesterol, but the cholesterol metabolism and its complex homeostasis regulation are currently poorly understood. This review will seek to integrate current knowledge about the brain cholesterol metabolism with molecular mechanisms.
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Affiliation(s)
- Juan Zhang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
| | - Qiang Liu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
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Abstract
Apolipoprotein E4 (apoE4), the most prevalent genetic risk factor for Alzheimer's disease (AD), is less lipidated than its corresponding AD-benign form, apoE3, and it has been suggested that the pathological effects of apoE4 are mediated by lipid-related mechanisms. ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1, respectively) are the most important apoE-lipidating proteins. The expression of these proteins, as well as that of apoE, is controlled by the transcription regulation retinoid X receptor (RXR)-liver X receptor (LXR) system. In the present study, we investigated the effects of the RXR agonist bexarotene on mRNA and protein levels of apoE, ABCA1, and ABCG1 in young, naive apoE3- and apoE4-targeted replacement mice and assessed the extent to which this reverses the apoE4-driven pathological phenotype. This investigation reveled that bexarotene increases the mRNA and protein levels of ABCA1 and ABCG1 in hippocampal neurons, but has no effect on the corresponding levels of apoE. These findings were associated with reversal of the lipidation deficiency of apoE4 and of the cognitive impairments of apoE4 mice in several tests. Furthermore, bexarotene reversed the apoE4-driven accumulation of Aβ42 and hyperphosphorylated tau in hippocampal neurons, as well as the apoE4-induced reduction in the levels of the presynaptic marker vesicular glutamatergic transporter 1 (VGluT1). In conclusion, the results show that treatment of apoE4 mice with the RXR agonist bexarotene reverses the apoE4-induced cognitive and neuronal impairments in vivo and suggest that this is due to reversal of the lipidation deficiency of apoE4. This puts forward the possibility that RXR activation and increased levels of ABCA1 and ABCG1 could be useful in the treatment of human apoE4 carriers.
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Lathe R, Sapronova A, Kotelevtsev Y. Atherosclerosis and Alzheimer--diseases with a common cause? Inflammation, oxysterols, vasculature. BMC Geriatr 2014; 14:36. [PMID: 24656052 PMCID: PMC3994432 DOI: 10.1186/1471-2318-14-36] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/26/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Aging is accompanied by increasing vulnerability to pathologies such as atherosclerosis (ATH) and Alzheimer disease (AD). Are these different pathologies, or different presentations with a similar underlying pathoetiology? DISCUSSION Both ATH and AD involve inflammation, macrophage infiltration, and occlusion of the vasculature. Allelic variants in common genes including APOE predispose to both diseases. In both there is strong evidence of disease association with viral and bacterial pathogens including herpes simplex and Chlamydophila. Furthermore, ablation of components of the immune system (or of bone marrow-derived macrophages alone) in animal models restricts disease development in both cases, arguing that both are accentuated by inflammatory/immune pathways. We discuss that amyloid β, a distinguishing feature of AD, also plays a key role in ATH. Several drugs, at least in mouse models, are effective in preventing the development of both ATH and AD. Given similar age-dependence, genetic underpinnings, involvement of the vasculature, association with infection, Aβ involvement, the central role of macrophages, and drug overlap, we conclude that the two conditions reflect different manifestations of a common pathoetiology. MECHANISM Infection and inflammation selectively induce the expression of cholesterol 25-hydroxylase (CH25H). Acutely, the production of 'immunosterol' 25-hydroxycholesterol (25OHC) defends against enveloped viruses. We present evidence that chronic macrophage CH25H upregulation leads to catalyzed esterification of sterols via 25OHC-driven allosteric activation of ACAT (acyl-CoA cholesterol acyltransferase/SOAT), intracellular accumulation of cholesteryl esters and lipid droplets, vascular occlusion, and overt disease. SUMMARY We postulate that AD and ATH are both caused by chronic immunologic challenge that induces CH25H expression and protection against particular infectious agents, but at the expense of longer-term pathology.
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Affiliation(s)
- Richard Lathe
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Pieta Research, PO Box 27069, Edinburgh EH10 5YW, UK
| | - Alexandra Sapronova
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Optical Research Group, Laboratory of Evolutionary Biophysics of Development, Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Yuri Kotelevtsev
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Biomedical Centre for Research Education and Innovation (CREI), Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Little France, Edinburgh EH16 4TJ, UK
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Hung YH, Bush AI, La Fontaine S. Links between copper and cholesterol in Alzheimer's disease. Front Physiol 2013; 4:111. [PMID: 23720634 PMCID: PMC3655288 DOI: 10.3389/fphys.2013.00111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/30/2013] [Indexed: 01/01/2023] Open
Abstract
Altered copper homeostasis and hypercholesterolemia have been identified independently as risk factors for Alzheimer's disease (AD). Abnormal copper and cholesterol metabolism are implicated in the genesis of amyloid plaques and neurofibrillary tangles (NFT), which are two key pathological signatures of AD. Amyloidogenic processing of a sub-population of amyloid precursor protein (APP) that produces Aβ occurs in cholesterol-rich lipid rafts in copper deficient AD brains. Co-localization of Aβ and a paradoxical high concentration of copper in lipid rafts fosters the formation of neurotoxic Aβ:copper complexes. These complexes can catalytically oxidize cholesterol to generate H2O2, oxysterols and other lipid peroxidation products that accumulate in brains of AD cases and transgenic mouse models. Tau, the core protein component of NFTs, is sensitive to interactions with copper and cholesterol, which trigger a cascade of hyperphosphorylation and aggregation preceding the generation of NFTs. Here we present an overview of copper and cholesterol metabolism in the brain, and how their integrated failure contributes to development of AD.
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Affiliation(s)
- Ya Hui Hung
- Oxidation Biology Laboratory, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia ; Centre for Neuroscience Research, The University of Melbourne Parkville, VIC, Australia
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Kang J, Rivest S. Lipid metabolism and neuroinflammation in Alzheimer's disease: a role for liver X receptors. Endocr Rev 2012; 33:715-46. [PMID: 22766509 DOI: 10.1210/er.2011-1049] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Liver X receptors (LXR) are nuclear receptors that have emerged as key regulators of lipid metabolism. In addition to their functions as cholesterol sensors, LXR have also been found to regulate inflammatory responses in macrophages. Alzheimer's disease (AD) is a neurodegenerative disease characterized by a progressive cognitive decline associated with inflammation. Evidence indicates that the initiation and progression of AD is linked to aberrant cholesterol metabolism and inflammation. Activation of LXR can regulate neuroinflammation and decrease amyloid-β peptide accumulation. Here, we highlight the role of LXR in orchestrating lipid homeostasis and neuroinflammation in the brain. In addition, diabetes mellitus is also briefly discussed as a significant risk factor for AD because of the appearing beneficial effects of LXR on glucose homeostasis. The ability of LXR to attenuate AD pathology makes them potential therapeutic targets for this neurodegenerative disease.
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Affiliation(s)
- Jihong Kang
- Department of Physiology and Pathophysiology and Key Laboratory of Molecular Cardiovascular Sciences, State Education Ministry, Peking University Health Science Center, Beijing 100191, China
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Chen J, Zhang X, Kusumo H, Costa LG, Guizzetti M. Cholesterol efflux is differentially regulated in neurons and astrocytes: implications for brain cholesterol homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:263-75. [PMID: 23010475 DOI: 10.1016/j.bbalip.2012.09.007] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/05/2012] [Accepted: 09/14/2012] [Indexed: 11/15/2022]
Abstract
Disruption of cholesterol homeostasis in the central nervous system (CNS) has been associated with neurological, neurodegenerative, and neurodevelopmental disorders. The CNS is a closed system with regard to cholesterol homeostasis, as cholesterol-delivering lipoproteins from the periphery cannot pass the blood-brain-barrier and enter the brain. Different cell types in the brain have different functions in the regulation of cholesterol homeostasis, with astrocytes producing and releasing apolipoprotein E and lipoproteins, and neurons metabolizing cholesterol to 24(S)-hydroxycholesterol. We present evidence that astrocytes and neurons adopt different mechanisms also in regulating cholesterol efflux. We found that in astrocytes cholesterol efflux is induced by both lipid-free apolipoproteins and lipoproteins, while cholesterol removal from neurons is triggered only by lipoproteins. The main pathway by which apolipoproteins induce cholesterol efflux is through ABCA1. By upregulating ABCA1 levels and by inhibiting its activity and silencing its expression, we show that ABCA1 is involved in cholesterol efflux from astrocytes but not from neurons. Furthermore, our results suggest that ABCG1 is involved in cholesterol efflux to apolipoproteins and lipoproteins from astrocytes but not from neurons, while ABCG4, whose expression is much higher in neurons than astrocytes, is involved in cholesterol efflux from neurons but not astrocytes. These results indicate that different mechanisms regulate cholesterol efflux from neurons and astrocytes, reflecting the different roles that these cell types play in brain cholesterol homeostasis. These results are important in understanding cellular targets of therapeutic drugs under development for the treatments of conditions associated with altered cholesterol homeostasis in the CNS.
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Affiliation(s)
- Jing Chen
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt way NE, Seattle, WA 98105, USA
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