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Feringa FM, Hertog SJKD, Wang L, Derks RJE, Kruijff I, Erlebach L, Heijneman J, Miramontes R, Pömpner N, Blomberg N, Olivier-Jimenez D, Johansen LE, Cammack AJ, Giblin A, Toomey CE, Rose IVL, Yuan H, Ward M, Isaacs AM, Kampmann M, Kronenberg-Versteeg D, Lashley T, Thompson LM, Ori A, Mohammed Y, Giera M, van der Kant R. The Neurolipid Atlas: a lipidomics resource for neurodegenerative diseases uncovers cholesterol as a regulator of astrocyte reactivity impaired by ApoE4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.01.601474. [PMID: 39005258 PMCID: PMC11244892 DOI: 10.1101/2024.07.01.601474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Lipid changes in the brain have been implicated in many neurodegenerative diseases including Alzheimer's Disease (AD), Parkinson's disease and Amyotrophic Lateral Sclerosis. To facilitate comparative lipidomic research across brain-diseases we established a data commons named the Neurolipid Atlas, that we have pre-populated with novel human, mouse and isogenic induced pluripotent stem cell (iPSC)-derived lipidomics data for different brain diseases. We show that iPSC-derived neurons, microglia and astrocytes display distinct lipid profiles that recapitulate in vivo lipotypes. Leveraging multiple datasets, we show that the AD risk gene ApoE4 drives cholesterol ester (CE) accumulation in human astrocytes recapitulating CE accumulation measured in the human AD brain. Multi-omic interrogation of iPSC-derived astrocytes revealed that cholesterol plays a major role in astrocyte interferon-dependent pathways such as the immunoproteasome and major histocompatibility complex (MHC) class I antigen presentation. We show that through enhanced cholesterol esterification ApoE4 suppresses immune activation of astrocytes. Our novel data commons, available at neurolipidatlas.com, provides a user-friendly tool and knowledge base for a better understanding of lipid dyshomeostasis in neurodegenerative diseases.
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Affiliation(s)
- Femke M Feringa
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Sascha J Koppes-den Hertog
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Lian Wang
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
| | - Rico J E Derks
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
| | - Iris Kruijff
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Lena Erlebach
- German Center for Neurodegenerative Diseases (DZNE) Tübingen, Tübingen, Germany
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jorin Heijneman
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Ricardo Miramontes
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Nadine Pömpner
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Niek Blomberg
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
| | - Damien Olivier-Jimenez
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
| | - Lill Eva Johansen
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Alexander J Cammack
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
- UK Dementia Research Institute at UCL, University College London, London, UK
| | - Ashling Giblin
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
- UK Dementia Research Institute at UCL, University College London, London, UK
| | - Christina E Toomey
- Department of Clinical and Molecular Neuroscience, Queen Square Institute of Neurology, University College London, London, UK
| | - Indigo V L Rose
- Institute for Neurodegenerative Diseases and Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Hebao Yuan
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Michael Ward
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
- UK Dementia Research Institute at UCL, University College London, London, UK
| | - Martin Kampmann
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
| | - Deborah Kronenberg-Versteeg
- German Center for Neurodegenerative Diseases (DZNE) Tübingen, Tübingen, Germany
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Tammaryn Lashley
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Leslie M Thompson
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Alessandro Ori
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Yassene Mohammed
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
- Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 0G4, Canada
| | - Martin Giera
- Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden, the Netherlands
| | - Rik van der Kant
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands
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Area-Gomez E, Schon EA. Towards a Unitary Hypothesis of Alzheimer's Disease Pathogenesis. J Alzheimers Dis 2024; 98:1243-1275. [PMID: 38578892 DOI: 10.3233/jad-231318] [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] [Indexed: 04/07/2024]
Abstract
The "amyloid cascade" hypothesis of Alzheimer's disease (AD) pathogenesis invokes the accumulation in the brain of plaques (containing the amyloid-β protein precursor [AβPP] cleavage product amyloid-β [Aβ]) and tangles (containing hyperphosphorylated tau) as drivers of pathogenesis. However, the poor track record of clinical trials based on this hypothesis suggests that the accumulation of these peptides is not the only cause of AD. Here, an alternative hypothesis is proposed in which the AβPP cleavage product C99, not Aβ, is the main culprit, via its role as a regulator of cholesterol metabolism. C99, which is a cholesterol sensor, promotes the formation of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM), a cholesterol-rich lipid raft-like subdomain of the ER that communicates, both physically and biochemically, with mitochondria. We propose that in early-onset AD (EOAD), MAM-localized C99 is elevated above normal levels, resulting in increased transport of cholesterol from the plasma membrane to membranes of intracellular organelles, such as ER/endosomes, thereby upregulating MAM function and driving pathology. By the same token, late-onset AD (LOAD) is triggered by any genetic variant that increases the accumulation of intracellular cholesterol that, in turn, boosts the levels of C99 and again upregulates MAM function. Thus, the functional cause of AD is upregulated MAM function that, in turn, causes the hallmark disease phenotypes, including the plaques and tangles. Accordingly, the MAM hypothesis invokes two key interrelated elements, C99 and cholesterol, that converge at the MAM to drive AD pathogenesis. From this perspective, AD is, at bottom, a lipid disorder.
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Affiliation(s)
- Estela Area-Gomez
- Department of Neurology, Columbia University, New York, NY, USA
- Centro de Investigaciones Biológicas "Margarita Salas", Spanish National Research Council, Madrid, Spain
| | - Eric A Schon
- Department of Neurology, Columbia University, New York, NY, USA
- Department of Genetics and Development>, Columbia University, New York, NY, USA
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Davra V, Benzeroual KE. Flavonoids and fibrate modulate apoE4-induced processing of amyloid precursor protein in neuroblastoma cells. Front Neurosci 2023; 17:1245895. [PMID: 38204816 PMCID: PMC10777729 DOI: 10.3389/fnins.2023.1245895] [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: 06/23/2023] [Accepted: 11/28/2023] [Indexed: 01/12/2024] Open
Abstract
Introduction Apolipoprotein (apo) E4, being a major genetic risk factor for Alzheimer's disease (AD), is actively involved in the proteolytic processing of amyloid precursor protein (APP) to amyloid β (Aβ) peptide, the principle constituent of amyloid plaques in Alzheimer Disease (AD) patients. ApoE4 is believed to affect APP processing through intracellular cholesterol homeostasis, whereas lowering the cholesterol level by pharmacological agents has been suggested to reduce Aβ production. This study has investigated the effects of hypolipidemic agents fenofibrate, and the flavonoids-naringenin and diosmetin-on apoE4-induced APP processing in rat neuroblastoma cells stably transfected with human wild-type APP 695 (B103-hAPP695wt). Results B103-hAPP695wt cells were pretreated with different doses of flavonoids and fenofibrate for 1 h prior to apoE4 exposure for 24 h. ApoE4-induced production of intra- and extracellular Aβ peptides has been reduced with fenofibrate, naringenin, and diosmetin treatments. Pretreatment with diosmetin has significantly reduced apoE4-induced full-length APP (fl- APP) expression, whereas naringenin and fenofibrate had no effect on it. In addition, the increase in the apoE4-induced secretion of sAPPtotal and sAPPα has been dose-dependently reduced with drug pretreatment. On the other hand, the decrease in the expression of both APP-carboxy terminal fragments (CTF)-α and -β (generated by the α- or β-secretase cleavage of APP) by apoE4 was dose-dependently increased in cells pretreated with fenofibrate and naringenin but not diosmetin. Conclusion Thus, we suggest that fenofibrate, naringenin, and diosmetin treatments can reduce apoE4- induced Aβ production by distinct mechanisms that may prove useful in developing drugs for AD patients.
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Affiliation(s)
| | - Kenza E. Benzeroual
- Department of Pharmaceutical Sciences, Arnold and Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, NY, United States
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4
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Rudajev V, Novotny J. Cholesterol-dependent amyloid β production: space for multifarious interactions between amyloid precursor protein, secretases, and cholesterol. Cell Biosci 2023; 13:171. [PMID: 37705117 PMCID: PMC10500844 DOI: 10.1186/s13578-023-01127-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 09/05/2023] [Indexed: 09/15/2023] Open
Abstract
Amyloid β is considered a key player in the development and progression of Alzheimer's disease (AD). Many studies investigating the effect of statins on lowering cholesterol suggest that there may be a link between cholesterol levels and AD pathology. Since cholesterol is one of the most abundant lipid molecules, especially in brain tissue, it affects most membrane-related processes, including the formation of the most dangerous form of amyloid β, Aβ42. The entire Aβ production system, which includes the amyloid precursor protein (APP), β-secretase, and the complex of γ-secretase, is highly dependent on membrane cholesterol content. Moreover, cholesterol can affect amyloidogenesis in many ways. Cholesterol influences the stability and activity of secretases, but also dictates their partitioning into specific cellular compartments and cholesterol-enriched lipid rafts, where the amyloidogenic machinery is predominantly localized. The most complicated relationships have been found in the interaction between cholesterol and APP, where cholesterol affects not only APP localization but also the precise character of APP dimerization and APP processing by γ-secretase, which is important for the production of Aβ of different lengths. In this review, we describe the intricate web of interdependence between cellular cholesterol levels, cholesterol membrane distribution, and cholesterol-dependent production of Aβ, the major player in AD.
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Affiliation(s)
- Vladimir Rudajev
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiri Novotny
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
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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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6
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Song J, Yuan C, Li W, Gao T, Lu X, Wang L. APP palmitoylation is involved in the increase in Aβ 1-42 induced by aluminum. Brain Res 2022; 1774:147709. [PMID: 34758347 DOI: 10.1016/j.brainres.2021.147709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 11/29/2022]
Abstract
The increase in Aβ1-42 is a neurotoxic effect induced by aluminum which can lead to impairment of learning and memory, but its mechanism has yet to be fully elucidated. Studies have shown that APP palmitoylation is appears to be involved in the production process of Aβ1-42. Here, we investigated whether APP palmitoylation is related to the increase in Aβ caused by aluminum and its specific mechanism of action. In this study, APP palmitoylation was studied in the setting of aluminum-induced increases in Aβ1-42 from two perspectives: whole animal experiments and in vitro cell experiments. First, the learning and memory of rats were impaired and the number of rat cortical neurons was decreased after staining with aluminum. Second, the expression of palmitoyl APP, APP in lipid rafts and palmitoyl acyltransferase zDHHC7 both in rat cerebral cortex and PC12 cells increased with the production of Aβ1-42 induced by aluminum in a dose-dependent manner. Finally, the intervention with the palmitoylation inhibitors 2-BP and siRNA zDHHC7 in PC12 cells reduced levels of palmitoyl APP, the expression of APP in lipid rafts and the content of Aβ1-42 induced by aluminum to a certain extent. Our results indicate that increased APP palmitoylation levels may be related to the increase in Aβ1-42 caused by aluminum, and the mechanism may involve APP palmitoylation promoting the accumulation of APP protein on lipid rafts and the cleavage of APP by BACE1 in amyloidogenic pathway. The increase in expression of zDHHC7 may be one of the reasons for the increase in levels of APP palmitoylation caused by aluminum.
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Affiliation(s)
- Jing Song
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China; Key Lab of Cellular Physiology of Education Ministry, Shanxi Medical University, China.
| | - Chunman Yuan
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China
| | - Wenjing Li
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China
| | - Ting Gao
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China
| | - Xiaoting Lu
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China; Key Lab of Cellular Physiology of Education Ministry, Shanxi Medical University, China
| | - Linping Wang
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China; Key Lab of Environmental Hazard and Health of Shanxi Province, Shanxi Medical University, China; Key Lab of Cellular Physiology of Education Ministry, Shanxi Medical University, China
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7
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Dutta S, Rahman S, Ahmad R, Kumar T, Dutta G, Banerjee S, Abubakar AR, Rowaiye AB, Dhingra S, Ravichandiran V, Kumar S, Sharma P, Haque M, Charan J. An evidence-based review of neuronal cholesterol role in dementia and statins as a pharmacotherapy in reducing risk of dementia. Expert Rev Neurother 2021; 21:1455-1472. [PMID: 34756134 DOI: 10.1080/14737175.2021.2003705] [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] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Dementia is a progressive neurodegenerative disorder impairing memory and cognition. Alzheimer's Disease, followed by vascular dementia - the most typical form. Risk factors for vascular dementia include diabetes, cardiovascular disease, hyperlipidemia. Lipids' levels are significantly associated with vascular changes in the brain. AREAS COVERED The present article reviews the cholesterol metabolism in the brain, which includes: the synthesis, transport, storage, and elimination process. Additionally, it reviews the role of cholesterol in the pathogenesis of dementia and statin as a therapeutic intervention in dementia. In addition to the above, it further reviews evidence in support of as well as against statin therapy in dementia, recent updates of statin pharmacology, and demerits of use of statin pharmacotherapy. EXPERT OPINION Amyloid-β peptides and intraneuronal neurofibrillary tangles are markers of Alzheimer's disease. Evidence shows cholesterol modulates the functioning of enzymes associated with Amyloid-β peptide processing and synthesis. Lowering cholesterol using statin may help prevent or delay the progression of dementia. This paper reviews the role of statin in dementia and recommends extensive future studies, including genetic research, to obtain a precise medication approach for patients with dementia.
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Affiliation(s)
- Siddhartha Dutta
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujrat, India
| | - Sayeeda Rahman
- School of Medicine, American University of Integrative Sciences, Bridgetown, Barbados
| | - Rahnuma Ahmad
- Department of Physiology, Medical College for Women and Hospital, Dhaka, Bangladesh
| | - Tarun Kumar
- Department of Pharmacology, All India Institute of Medical Sciences (AIIMS), Jodhpur, Rajasthan, India
| | - Gitashree Dutta
- Department of Community Medicine, Neigrihms, Shillong, India
| | | | - Abdullahi Rabiu Abubakar
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Bayero University, Kano, Nigeria
| | - Adekunle Babajide Rowaiye
- Department of Pharmaceutical Microbiology and Biotechnology, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Awka, Nigeria
| | - Sameer Dhingra
- Department of Pharmacy Practice, National Institute of Pharmaceutical Education and Research (NIPER), Hajipur, India
| | - Velayutham Ravichandiran
- Department of Natural Products, National Institute of Pharmaceutical Education and Research-Kolkata, Kolkata, India
| | - Santosh Kumar
- Department of Periodontology and Implantology, Karnavati University, Gandhinagar, India
| | - Paras Sharma
- Department of Pharmacognosy, BVM College of Pharmacy, Gwalior, India
| | - Mainul Haque
- Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia (National Defence University of Malaysia), Kem Perdana Sungai Besi, Kuala Lumpur, Malaysia
| | - Jaykaran Charan
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujrat, India
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8
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Zhu Y, Kim SQ, Zhang Y, Liu Q, Kim KH. Pharmacological inhibition of acyl-coenzyme A:cholesterol acyltransferase alleviates obesity and insulin resistance in diet-induced obese mice by regulating food intake. Metabolism 2021; 123:154861. [PMID: 34371065 DOI: 10.1016/j.metabol.2021.154861] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND/OBJECTIVES Acyl-coenzyme A:cholesterol acyltransferases (ACATs) catalyze the formation of cholesteryl ester (CE) from free cholesterol to regulate intracellular cholesterol homeostasis. Despite the well-documented role of ACATs in hypercholesterolemia and their emerging role in cancer and Alzheimer's disease, the role of ACATs in adipose lipid metabolism and obesity is poorly understood. Herein, we investigated the therapeutic potential of pharmacological inhibition of ACATs in obesity. METHODS We administrated avasimibe, an ACAT inhibitor, or vehicle to high-fat diet-induced obese (DIO) mice via intraperitoneal injection and evaluated adiposity, food intake, energy expenditure, and glucose homeostasis. Moreover, we examined the effect of avasimibe on the expressions of the genes in adipogenesis, lipogenesis, inflammation and adipose pathology in adipose tissue by real-time PCR. We also performed a pair feeding study to determine the mechanism for body weight lowering effect of avasimibe. RESULTS Avasimibe treatment markedly decreased body weight, body fat content and food intake with increased energy expenditure in DIO mice. Avasimibe treatment significantly lowered blood levels of glucose and insulin, and improved glucose tolerance in obese mice. The beneficial effects of avasimibe were associated with lower levels of adipocyte-specific genes in adipose tissue and the suppression of food intake. Using a pair-feeding study, we further demonstrated that avasimibe-promoted weight loss is attributed mainly to the reduction of food intake. CONCLUSIONS These results indicate that avasimibe ameliorates obesity and its-related insulin resistance in DIO mice through, at least in part, suppression of food intake.
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Affiliation(s)
- Yuyan Zhu
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA; Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
| | - Sora Q Kim
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Yuan Zhang
- College of Food Science, Southwest University, Chongqing 400715, China
| | - Qing Liu
- Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Kee-Hong Kim
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA; Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA.
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9
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Feringa FM, van der Kant R. Cholesterol and Alzheimer's Disease; From Risk Genes to Pathological Effects. Front Aging Neurosci 2021; 13:690372. [PMID: 34248607 PMCID: PMC8264368 DOI: 10.3389/fnagi.2021.690372] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
While the central nervous system compromises 2% of our body weight, it harbors up to 25% of the body's cholesterol. Cholesterol levels in the brain are tightly regulated for physiological brain function, but mounting evidence indicates that excessive cholesterol accumulates in Alzheimer's disease (AD), where it may drive AD-associated pathological changes. This seems especially relevant for late-onset AD, as several of the major genetic risk factors are functionally associated with cholesterol metabolism. In this review we discuss the different systems that maintain brain cholesterol metabolism in the healthy brain, and how dysregulation of these processes can lead, or contribute to, Alzheimer's disease. We will also discuss how AD-risk genes might impact cholesterol metabolism and downstream AD pathology. Finally, we will address the major outstanding questions in the field and how recent technical advances in CRISPR/Cas9-gene editing and induced pluripotent stem cell (iPSC)-technology can aid to study these problems.
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Affiliation(s)
- Femke M. Feringa
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam University Medical Center, Amsterdam, Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, Netherlands
| | - Rik van der Kant
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Amsterdam, Netherlands
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10
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Bhattacharyya R, Black SE, Lotlikar MS, Fenn RH, Jorfi M, Kovacs DM, Tanzi RE. Axonal generation of amyloid-β from palmitoylated APP in mitochondria-associated endoplasmic reticulum membranes. Cell Rep 2021; 35:109134. [PMID: 34010653 PMCID: PMC8287518 DOI: 10.1016/j.celrep.2021.109134] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 02/09/2021] [Accepted: 04/23/2021] [Indexed: 11/14/2022] Open
Abstract
Axonal generation of Alzheimer’s disease (AD)-associated amyloid-β (Aβ) plays a key role in AD neuropathology, but the cellular mechanisms involved in its release have remained elusive. We previously reported that palmitoylated APP (palAPP) partitions to lipid rafts where it serves as a preferred substrate for β-secretase. Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) are cholesterol-rich lipid rafts that are upregulated in AD. Here, we show that downregulating MAM assembly by either RNA silencing or pharmacological modulation of the MAM-resident sigma1 receptor (S1R) leads to attenuated β-secretase cleavage of palAPP. Upregulation of MAMs promotes trafficking of palAPP to the cell surface, β-secretase cleavage, and Aβ generation. We develop a microfluidic device and use it to show that MAM levels alter Aβ generation specifically in neuronal processes and axons, but not in cell bodies. These data suggest therapeutic strategies for reducing axonal release of Aβ and attenuating β-amyloid pathology in AD. Bhattacharyya et al. show that the modulation of mitochondrial-associated endoplasmic reticulum membranes (MAMs) via sigma-1 receptor regulates Aβ generation from axons via cell surface trafficking and β-secretase cleavage of MAM-resident palmitoylated APP (palAPP).
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Affiliation(s)
- Raja Bhattacharyya
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Sophia E Black
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Madhura S Lotlikar
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rebecca H Fenn
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mehdi Jorfi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Dora M Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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11
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Wang K, Zhang W. Mitochondria-associated endoplasmic reticulum membranes: At the crossroad between familiar and sporadic Alzheimer's disease. Synapse 2021; 75:e22196. [PMID: 33559220 DOI: 10.1002/syn.22196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia and is incurable. The widely accepted amyloid hypothesis failed to produce efficient clinical therapies. In contrast, there is increasing evidence suggesting that the disruption of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) is a critical upstream event of AD pathogenesis. Here, we review MAM's role in some AD symptoms such as plaque formation, tau hyperphosphorylation, synaptic loss, aberrant lipid synthesis, disturbed calcium homeostasis, and abnormal autophagy. At last, we proposed that MAM plays a central role in familial AD (FAD) and sporadic AD (SAD).
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Affiliation(s)
- Kangrun Wang
- Xiangya Hospital, Central South University, Changsha, P.R. China
| | - Wenling Zhang
- The Third Xiangya Hospital, Central South University, Changsha, P.R. China
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12
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Langness VF, van der Kant R, Das U, Wang L, Chaves RDS, Goldstein LSB. Cholesterol-lowering drugs reduce APP processing to Aβ by inducing APP dimerization. Mol Biol Cell 2020; 32:247-259. [PMID: 33296223 PMCID: PMC8098827 DOI: 10.1091/mbc.e20-05-0345] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Amyloid beta (Aβ) is a major component of amyloid plaques, which are a key pathological hallmark found in the brains of Alzheimer’s disease (AD) patients. We show that statins are effective at reducing Aβ in human neurons from nondemented control subjects, as well as subjects with familial AD and sporadic AD. Aβ is derived from amyloid precursor protein (APP) through sequential proteolytic cleavage by BACE1 and γ-secretase. While previous studies have shown that cholesterol metabolism regulates APP processing to Aβ, the mechanism is not well understood. We used iPSC-derived neurons and bimolecular fluorescence complementation assays in transfected cells to elucidate how altering cholesterol metabolism influences APP processing. Altering cholesterol metabolism using statins decreased the generation of sAPPβ and increased levels of full-length APP (flAPP), indicative of reduced processing of APP by BACE1. We further show that statins decrease flAPP interaction with BACE1 and enhance APP dimerization. Additionally, statin-induced changes in APP dimerization and APP-BACE1 are dependent on cholesterol binding to APP. Our data indicate that statins reduce Aβ production by decreasing BACE1 interaction with flAPP and suggest that this process may be regulated through competition between APP dimerization and APP cholesterol binding.
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Affiliation(s)
- Vanessa F Langness
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Rik van der Kant
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam de Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.,Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1118, 1081 HZ Amsterdam, The Netherlands
| | - Utpal Das
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Louie Wang
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Rodrigo Dos Santos Chaves
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
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13
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Alavez-Rubio JS, Martínez-Rodríguez N, Escobedo-de-la-Peña J, Garrido-Acosta O, Juárez-Cedillo T. Relationship Between Genetic Variants of ACAT1 and APOE with the Susceptibility to Dementia (SADEM Study). Mol Neurobiol 2020; 58:905-912. [PMID: 33057949 DOI: 10.1007/s12035-020-02162-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/06/2020] [Indexed: 12/29/2022]
Abstract
One of the hypotheses that have emerged to explain the origin of dementia relates the disease with altered lipid metabolism, particularly cholesterol. To maintain cholesterol homeostasis, the ACAT1 enzyme has an important function to regulate the production of Aβ. Moreover, APOE is the main cholesterol carrier in the brain, and it has been reported as a risk factor for this disease. This study evaluates the relationship between ACAT1 and APOE genetic variants with susceptibility for the development of Alzheimer's disease and other dementias. We examined four ACAT1 polymorphisms (rs2247071, rs2862616, rs3753526, rs1044925) and two in the APOE gene (rs7412, rs429358) in a group of 204 controls and 196 cases of dementia. Our results show one protective haplotype: CGCA (OR = 0.34, 95% CI = 0.23-0.46; p < 0.001) and one risk haplotype: CGGA (OR = 1.87, 95% CI = 1.34-2.60; p < 0.001) for the development of dementia. Subjects identified as APOE-ε4 allele carriers had a higher risk of developing dementia compared with non-carriers, OR = 13.33 (95% CI = 3.14-56.31). The results support the hypothesis that the ACAT1 gene, together with the APOE gene, plays an important role in susceptibility to the development of dementia and shows genetic characteristics of the Mexican population that can be used to identify the population at risk.
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Affiliation(s)
| | - Nancy Martínez-Rodríguez
- Epidemiology, Endocrinology and Nutrition Research Unit Hospital Infantil de México Federico Gomez Mexico City Mexico Ministry of Health (SSA), Mexico City, Mexico
| | - Jorge Escobedo-de-la-Peña
- Unidad de Investigación en Epidemiológica Clínica, Hospital General Regional Núm. 1 Dr. Carlos Mac Gregor Sánchez Navarro, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Osvaldo Garrido-Acosta
- Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Teresa Juárez-Cedillo
- Unidad de Investigación Epidemiológica y en Servicios de Salud, Área Envejecimiento, Centro Médico Nacional Siglo XXIAQ2 Instituto Mexicano del Seguro Social, Mexico City, Mexico. .,Unidad de Investigación en Epidemiología Clínica Hospital General Regional No 1 Carlos Mcgregor Sánchez Navarro Gabriel Mancera 222 esq. Xola. Col. Del Valle. Del. Benito Juárez CP 03100 Ciudad de Mexico, Mexico City, Mexico.
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14
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Alavez-Rubio JS, Juarez-Cedillo T. ACAT1 as a Therapeutic Target and its Genetic Relationship with Alzheimer's Disease. Curr Alzheimer Res 2020; 16:699-709. [PMID: 31441726 DOI: 10.2174/1567205016666190823125245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/14/2019] [Accepted: 08/08/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Alzheimer´s disease (AD) is a chronic and progressive disease which impacts caregivers, families and societies physically, psychologically and economically. Currently available drugs can only improve cognitive symptoms, have no impact on progression and are not curative, so identifying and studying new drug targets is important. There are evidences which indicate disturbances in cholesterol homeostasis can be related with AD pathology, especially the compartmentation of intracellular cholesterol and cytoplasmic cholesterol esters formed by acyl-CoA: cholesterol acyltransferase 1 (ACAT1) can be implicated in the regulation of amyloid-beta (Aβ) peptide, involved in AD. Blocking ACAT1 activity, beneficial effects are obtained, so it has been suggested that ACAT1 can be a potential new therapeutic target. The present review discusses the role of cholesterol homeostasis in AD pathology, especially with ACAT inhibitors, and how they have been raised as a therapeutic approach. In addition, the genetic relationship of ACAT and AD is discussed. CONCLUSION Although there are several lines of evidence from cell-based and animal studies that suggest that ACAT inhibition is an effective way of reducing cerebral Aβ, there is still an information gap in terms of mechanisms and concerns to cover before passing to the next level. Additionally, an area of interest that may be useful in understanding AD to subsequently propose new therapeutic approaches is pharmacogenetics; however, there is still a lot of missing information in this area.
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Affiliation(s)
| | - Teresa Juarez-Cedillo
- Unidad de Investigacion Epidemiologica y en Servicios de Salud, Area Envejecimiento, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (Actualmente comisionada en la Unidad de Investigacion en Epidemiologia, Clínica, Hospital Regional, Num. 1 Dr. Carlos MacGregor Sanchez Navarro IMSS), Mexico
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15
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Amyloid-β-independent regulators of tau pathology in Alzheimer disease. Nat Rev Neurosci 2019; 21:21-35. [PMID: 31780819 DOI: 10.1038/s41583-019-0240-3] [Citation(s) in RCA: 312] [Impact Index Per Article: 62.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2019] [Indexed: 12/12/2022]
Abstract
The global epidemic of Alzheimer disease (AD) is worsening, and no approved treatment can revert or arrest progression of this disease. AD pathology is characterized by the accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles in the brain. Genetic data, as well as autopsy and neuroimaging studies in patients with AD, indicate that Aβ plaque deposition precedes cortical tau pathology. Because Aβ accumulation has been considered the initial insult that drives both the accumulation of tau pathology and tau-mediated neurodegeneration in AD, the development of AD therapeutics has focused mostly on removing Aβ from the brain. However, striking preclinical evidence from AD mouse models and patient-derived human induced pluripotent stem cell models indicates that tau pathology can progress independently of Aβ accumulation and arises downstream of genetic risk factors for AD and aberrant metabolic pathways. This Review outlines novel insights from preclinical research that implicate apolipoprotein E, the endocytic system, cholesterol metabolism and microglial activation as Aβ-independent regulators of tau pathology. These factors are discussed in the context of emerging findings from clinical pathology, functional neuroimaging and other approaches in humans. Finally, we discuss the implications of these new insights for current Aβ-targeted strategies and highlight the emergence of novel therapeutic strategies that target processes upstream of both Aβ and tau.
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16
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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: 203] [Impact Index Per Article: 40.6] [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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17
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Petek B, Villa-Lopez M, Loera-Valencia R, Gerenu G, Winblad B, Kramberger MG, Ismail MAM, Eriksdotter M, Garcia-Ptacek S. Connecting the brain cholesterol and renin-angiotensin systems: potential role of statins and RAS-modifying medications in dementia. J Intern Med 2018; 284:620-642. [PMID: 30264910 DOI: 10.1111/joim.12838] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Millions of people worldwide receive agents targeting the renin-angiotensin system (RAS) to treat hypertension or statins to lower cholesterol. The RAS and cholesterol metabolic pathways in the brain are autonomous from their systemic counterparts and are interrelated through the cholesterol metabolite 27-hydroxycholesterol (27-OHC). These systems contribute to memory and dementia pathogenesis through interference in the amyloid-beta cascade, vascular mechanisms, glucose metabolism, apoptosis, neuroinflammation and oxidative stress. Previous studies examining the relationship between these treatments and cognition and dementia risk have produced inconsistent results. Defining the blood-brain barrier penetration of these medications has been challenging, and the mechanisms of action on cognition are not clearly established. Potential biases are apparent in epidemiological and clinical studies, such as reverse epidemiology, indication bias, problems defining medication exposure, uncertain and changing doses, and inappropriate grouping of outcomes and medications. This review summarizes current knowledge of the brain cholesterol and RAS metabolism and the mechanisms by which these pathways affect neurodegeneration. The putative mechanisms of action of statins and medications inhibiting the RAS will be examined, together with prior clinical and animal studies on their effects on cognition. We review prior epidemiological studies, analysing their strengths and biases, and identify areas for future research. Understanding the pathophysiology of the brain cholesterol system and RAS and their links to neurodegeneration has enormous potential. In future, well-designed epidemiological studies could identify potential treatments for Alzheimer's disease (AD) amongst medications that are already in use for other indications.
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Affiliation(s)
- B Petek
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, University Medical Centre, Ljubljana, Slovenia.,University of Ljubljana, Ljubljana, Slovenia
| | - M Villa-Lopez
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - R Loera-Valencia
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - G Gerenu
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Neurosciences, Biodonostia Health Research Institute, San Sebastian, Spain.,Center for Networked Biomedical Research in Neurodegenerative Diseases, CIBERNED, Health Institute Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain
| | - B Winblad
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Geriatric Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - M G Kramberger
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, University Medical Centre, Ljubljana, Slovenia.,University of Ljubljana, Ljubljana, Slovenia
| | - M-A-M Ismail
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Theme Neuro, Diseases of the Nervous System patient flow, Karolinska University Hospital, Huddinge, Sweden
| | - M Eriksdotter
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Geriatric Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - S Garcia-Ptacek
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Internal Medicine, Neurology Section, Södersjukhuset, Stockholm, Sweden
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18
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Kotani R, Urano Y, Sugimoto H, Noguchi N. Decrease of Amyloid-β Levels by Curcumin Derivative via Modulation of Amyloid-β Protein Precursor Trafficking. J Alzheimers Dis 2017; 56:529-542. [DOI: 10.3233/jad-160794] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Rina Kotani
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Yasuomi Urano
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Hachiro Sugimoto
- Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Noriko Noguchi
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
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19
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Aufschnaiter A, Kohler V, Diessl J, Peselj C, Carmona-Gutierrez D, Keller W, Büttner S. Mitochondrial lipids in neurodegeneration. Cell Tissue Res 2017; 367:125-140. [PMID: 27449929 PMCID: PMC5203858 DOI: 10.1007/s00441-016-2463-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/24/2016] [Indexed: 01/10/2023]
Abstract
Mitochondrial dysfunction is a common feature of many neurodegenerative diseases, including proteinopathies such as Alzheimer's or Parkinson's disease, which are characterized by the deposition of aggregated proteins in the form of insoluble fibrils or plaques. The distinct molecular processes that eventually result in mitochondrial dysfunction during neurodegeneration are well studied but still not fully understood. However, defects in mitochondrial fission and fusion, mitophagy, oxidative phosphorylation and mitochondrial bioenergetics have been linked to cellular demise. These processes are influenced by the lipid environment within mitochondrial membranes as, besides membrane structure and curvature, recruitment and activity of different proteins also largely depend on the respective lipid composition. Hence, the interaction of neurotoxic proteins with certain lipids and the modification of lipid composition in different cell compartments, in particular mitochondria, decisively impact cell death associated with neurodegeneration. Here, we discuss the relevance of mitochondrial lipids in the pathological alterations that result in neuronal demise, focussing on proteinopathies.
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Affiliation(s)
- Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Jutta Diessl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Carlotta Peselj
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Didac Carmona-Gutierrez
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria.
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden.
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20
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Bhattacharyya R, Fenn RH, Barren C, Tanzi RE, Kovacs DM. Palmitoylated APP Forms Dimers, Cleaved by BACE1. PLoS One 2016; 11:e0166400. [PMID: 27875558 PMCID: PMC5119739 DOI: 10.1371/journal.pone.0166400] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/30/2016] [Indexed: 11/26/2022] Open
Abstract
A major rate-limiting step for Aβ generation and deposition in Alzheimer's disease brains is BACE1-mediated cleavage (β-cleavage) of the amyloid precursor protein (APP). We previously reported that APP undergoes palmitoylation at two cysteine residues (Cys186 and Cys187) in the E1-ectodomain. 8-10% of total APP is palmitoylated in vitro and in vivo. Palmitoylated APP (palAPP) shows greater preference for β-cleavage than total APP in detergent resistant lipid rafts. Protein palmitoylation is known to promote protein dimerization. Since dimerization of APP at its E1-ectodomain results in elevated BACE1-mediated cleavage of APP, we have now investigated whether palmitoylation of APP affects its dimerization and whether this leads to elevated β-cleavage of the protein. Here we report that over 90% of palAPP is dimerized while only ~20% of total APP forms dimers. PalAPP-dimers are predominantly cis-oriented while total APP dimerizes in both cis- and trans-orientation. PalAPP forms dimers 4.5-times more efficiently than total APP. Overexpression of the palmitoylating enzymes DHHC7 and DHHC21 that increase palAPP levels and Aβ release, also increased APP dimerization in cells. Conversely, inhibition of APP palmitoylation by pharmacological inhibitors reduced APP-dimerization in coimmunoprecipitation and FLIM/FRET assays. Finally, in vitro BACE1-activity assays demonstrate that palmitoylation-dependent dimerization of APP promotes β-cleavage of APP in lipid-rich detergent resistant cell membranes (DRMs), when compared to total APP. Most importantly, generation of sAPPβ-sAPPβ dimers is dependent on APP-palmitoylation while total sAPPβ generation is not. Since BACE1 shows preference for palAPP dimers over total APP, palAPP dimers may serve as novel targets for effective β-cleavage inhibitors of APP as opposed to BACE1 inhibitors.
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Affiliation(s)
- Raja Bhattacharyya
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Rebecca H. Fenn
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Cory Barren
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Dora M. Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
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Löffler T, Schweinzer C, Flunkert S, Sántha M, Windisch M, Steyrer E, Hutter-Paier B. Brain cortical cholesterol metabolism is highly affected by human APP overexpression in mice. Mol Cell Neurosci 2016; 74:34-41. [DOI: 10.1016/j.mcn.2016.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 12/27/2022] Open
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Abstract
Alzheimer's disease (AD) is the most common cause of dementia with no cure at present. Cholesterol metabolism is closely associated with AD at several stages. ACAT1 converts free cholesterol to cholesteryl esters, and plays important roles in cellular cholesterol homeostasis. Recent studies show that in a mouse model, blocking ACAT1 provides multiple beneficial effects on AD. Here we review the current evidence that implicates ACAT1 as a therapeutic target for AD. We also discuss the potential usage of various ACAT inhibitors currently available to treat AD.
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Zhu M, Zhao X, Chen J, Xu J, Hu G, Guo D, Li Q, Zhang X, Chang CCY, Song B, Xiong Y, Chang T, Li B. ACAT1 regulates the dynamics of free cholesterols in plasma membrane which leads to the APP-α-processing alteration. Acta Biochim Biophys Sin (Shanghai) 2015; 47:951-9. [PMID: 26474739 DOI: 10.1093/abbs/gmv101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/14/2015] [Indexed: 12/13/2022] Open
Abstract
Acyl-CoA:cholesterol acyltransferase 1 (ACAT1) is a key enzyme exclusively using free cholesterols as the substrates in cell and is involved in the cellular cholesterol homeostasis. In this study, we used human neuroblastoma cell line SK-N-SH as a model and first observed that inhibiting ACAT1 can decrease the amyloid precursor protein (APP)-α-processing. Meanwhile, the transfection experiments using the small interfering RNA and expression plasmid of ACAT1 indicated that ACAT1 can dependently affect the APP-α-processing. Furthermore, inhibiting ACAT1 was found to increase the free cholesterols in plasma membrane (PM-FC), and the increased PM-FC caused by inhibiting ACAT1 can lead to the decrease of the APP-α-processing, indicating that ACAT1 regulates the dynamics of PM-FC, which leads to the alteration of the APP-α-processing. More importantly, further results showed that under the ACAT1 inhibition, the alterations of the PM-FC and the subsequent APP-α-processing are not dependent on the cellular total cholesterol level, confirming that ACAT1 regulates the dynamics of PM-FC. Finally, we revealed that even when the Niemann-Pick-Type C-dependent pathway is blocked, the ACAT1 inhibition still obviously results in the PM-FC increase, suggesting that the ACAT1-dependent pathway is responsible for the shuttling of PM-FC to the intracellular pool. Our data provide a novel insight that ACAT1 which enzymatically regulates the dynamics of PM-FC may play important roles in the human neuronal cells.
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Affiliation(s)
- Ming Zhu
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaonan Zhao
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jia Chen
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jiajia Xu
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guangjing Hu
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Dongqing Guo
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qin Li
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaowei Zhang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Catherine C Y Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Baoliang Song
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China College of Life Sciences, The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Ying Xiong
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tayuan Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Boliang Li
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Bahety P, Van Nguyen TH, Hong Y, Zhang L, Chan ECY, Ee PLR. Understanding the cholesterol metabolism-perturbing effects of docosahexaenoic acid by gas chromatography-mass spectrometry targeted metabonomic profiling. Eur J Nutr 2015; 56:29-43. [PMID: 26428672 DOI: 10.1007/s00394-015-1053-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 09/17/2015] [Indexed: 01/13/2023]
Abstract
PURPOSE Over the past few decades, docosahexaenoic acid (DHA) has gained special attention for management of cholesterol-associated metabolic disorders and neurodegenerative diseases such as Alzheimer's disease (AD) owing to its neuroprotective, anti-inflammatory and hypolipidemic properties. Several epidemiological studies have reported the effect of DHA in reducing the risk of developing AD by lowering cholesterol. Hypercholesterolemia is a pro-amyloidogenic factor influencing the enzymatic processing of amyloid-β precursor protein (AβPP) to toxic β-amyloid. However, the mechanism by which DHA modulates the cholesterol pathway has not been established. Thus, the objective of this study was to investigate the mechanism of regulation of cholesterol metabolism by DHA in an AβPP695 overexpressing AD cell model. METHODS A gas chromatography/mass spectrometry method was developed and validated for the targeted profiling of 11 cholesterol metabolites in DHA-treated Chinese hamster ovary wild-type (CHO-wt) and AβPP695 overexpressing (CHO-AβPP695) cells. The differential metabolite profiles between DHA- and vehicle-treated groups were further analyzed using fold change values of the ratio of concentration of metabolites in CHO-AβPP695 to CHO-wt cells. Effect of DHA on key rate-limiting enzymatic activities within the cholesterol pathway was established using biochemical assays. RESULTS Our results showed that DHA reduced the levels of key cholesterol anabolites and catabolites in CHO-AβPP695 cells as compared to CHO-wt cells. Further enzymatic studies revealed that the cholesterol-lowering effect of DHA was mediated by regulating HMG-CoA reductase and squalene epoxidase enzyme activities. CONCLUSION We demonstrate for the first time the dual effects of DHA in inhibiting HMG-CoA reductase and squalene epoxidase and modulating the sterol biosynthesis axis of the cholesterol pathway in AβPP695 overexpressing AD. Our novel findings underscore the potential of DHA as a multi-target hypocholesterolemic agent for the prophylaxis of AD and other cholesterol-associated diseases.
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Affiliation(s)
- Priti Bahety
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore
| | - Thi Hai Van Nguyen
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore
| | - Yanjun Hong
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore
| | - Luqi Zhang
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore.
| | - Pui Lai Rachel Ee
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Republic of Singapore.
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Tam JHK, Seah C, Pasternak SH. The Amyloid Precursor Protein is rapidly transported from the Golgi apparatus to the lysosome and where it is processed into beta-amyloid. Mol Brain 2014; 7:54. [PMID: 25085554 PMCID: PMC4237969 DOI: 10.1186/s13041-014-0054-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/23/2014] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by cerebral deposition of β-amyloid peptide (Aβ). Aβ is produced by sequential cleavage of the Amyloid Precursor Protein (APP) by β- and γ-secretases. Many studies have demonstrated that the internalization of APP from the cell surface can regulate Aβ production, although the exact organelle in which Aβ is produced remains contentious. A number of recent studies suggest that intracellular trafficking also plays a role in regulating Aβ production, but these pathways are relatively under-studied. The goal of this study was to elucidate the intracellular trafficking of APP, and to examine the site of intracellular APP processing. RESULTS We have tagged APP on its C-terminal cytoplasmic tail with photoactivatable Green Fluorescent Protein (paGFP). By photoactivating APP-paGFP in the Golgi, using the Golgi marker Galactosyltranferase fused to Cyan Fluorescent Protein (GalT-CFP) as a target, we are able to follow a population of nascent APP molecules from the Golgi to downstream compartments identified with compartment markers tagged with red fluorescent protein (mRFP or mCherry); including rab5 (early endosomes) rab9 (late endosomes) and LAMP1 (lysosomes). Because γ-cleavage of APP releases the cytoplasmic tail of APP including the photoactivated GFP, resulting in loss of fluorescence, we are able to visualize the cleavage of APP in these compartments. Using APP-paGFP, we show that APP is rapidly trafficked from the Golgi apparatus to the lysosome; where it is rapidly cleared. Chloroquine and the highly selective γ-secretase inhibitor, L685, 458, cause the accumulation of APP in lysosomes implying that APP is being cleaved by secretases in the lysosome. The Swedish mutation dramatically increases the rate of lysosomal APP processing, which is also inhibited by chloroquine and L685, 458. By knocking down adaptor protein 3 (AP-3; a heterotetrameric protein complex required for trafficking many proteins to the lysosome) using siRNA, we are able to reduce this lysosomal transport. Blocking lysosomal transport of APP reduces Aβ production by more than a third. CONCLUSION These data suggests that AP-3 mediates rapid delivery of APP to lysosomes, and that the lysosome is a likely site of Aβ production.
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Affiliation(s)
- Joshua HK Tam
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, 100 Perth Drive, London N6A 5K8, Ontario, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London N6A 5K8, Ontario, Canada
| | - Claudia Seah
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, 100 Perth Drive, London N6A 5K8, Ontario, Canada
| | - Stephen H Pasternak
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, 100 Perth Drive, London N6A 5K8, Ontario, Canada
- Department of Clinical Neurological Sciences, London N6A 5K8, Ontario, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London N6A 5K8, Ontario, Canada
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Merezhko M, Muggalla P, Nykänen NP, Yan X, Sakha P, Huttunen HJ. Multiplex assay for live-cell monitoring of cellular fates of amyloid-β precursor protein (APP). PLoS One 2014; 9:e98619. [PMID: 24932508 PMCID: PMC4059622 DOI: 10.1371/journal.pone.0098619] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/05/2014] [Indexed: 11/19/2022] Open
Abstract
Amyloid-β precursor protein (APP) plays a central role in pathogenesis of Alzheimer's disease. APP has a short half-life and undergoes complex proteolytic processing that is highly responsive to various stimuli such as changes in cellular lipid or energy homeostasis. Cellular trafficking of APP is controlled by its large protein interactome, including dozens of cytosolic adaptor proteins, and also by interactions with lipids. Currently, cellular regulation of APP is mostly studied based on appearance of APP-derived proteolytic fragments to conditioned media and cellular extracts. Here, we have developed a novel live-cell assay system based on several indirect measures that reflect altered APP trafficking and processing in cells. Protein-fragment complementation assay technology for detection of APP-BACE1 protein-protein interaction forms the core of the new assay. In a multiplex form, the assay can measure four endpoints: total cellular APP level, total secreted sAPP level in media, APP-BACE1 interaction in cells and in exosomes released by the cells. Functional validation of the assay with pharmacological and genetic tools revealed distinct patterns of cellular fates of APP, with immediate mechanistic implications. This new technology will facilitate functional genomics studies of late-onset Alzheimer's disease, drug discovery efforts targeting APP and characterization of the physiological functions of APP and its proteolytic fragments.
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Affiliation(s)
- Maria Merezhko
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | | | | | - Xu Yan
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Prasanna Sakha
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Henri J. Huttunen
- Neuroscience Center, University of Helsinki, Helsinki, Finland
- * E-mail: .
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Sun JH, Yu JT, Tan L. The Role of Cholesterol Metabolism in Alzheimer’s Disease. Mol Neurobiol 2014; 51:947-65. [DOI: 10.1007/s12035-014-8749-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/07/2014] [Indexed: 12/25/2022]
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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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Abstract
AbstractAlzheimer’s disease (AD) is a neurodegenerative disorder that is characterized by normal memory loss and cognitive impairment in humans. Many drug targets and disease-modulating therapies are available for treatment of AD, but none of these are effective enough in reducing problems associated with recognition and memory. Potential drug targets so far reported for AD are β-secretase, Γ-secretase, amyloid beta (Aβ) and Aβ fibrils, glycogen synthase kinase-3 (GSK-3), acyl-coenzyme A: cholesterol acyl-transferase (ACAT) and acetylcholinesterase (AChE). Herbal remedies (antioxidants) and natural metal-chelators have shown a very significant role in reducing the risk of AD, as well as lowering the effect of Aβ in AD patients. Researchers are working in the direction of antisense and stem cell-based therapies for a cure for AD, which mainly depends on the clearance of misfolded protein deposits — including Aβ, tau, and alpha-synuclein. Computational approaches for inhibitor designing, interaction analysis, principal descriptors and an absorption, distribution, metabolism, excretion and toxicity (ADMET) study could speed up the process of drug development with higher efficacy and less chance of failure. This paper reviews the known drugs, drug targets, and existing and future therapies for the treatment of AD.
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Palmitoylation of amyloid precursor protein regulates amyloidogenic processing in lipid rafts. J Neurosci 2013; 33:11169-83. [PMID: 23825420 DOI: 10.1523/jneurosci.4704-12.2013] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Brains of patients affected by Alzheimer's disease (AD) contain large deposits of aggregated amyloid β-protein (Aβ). Only a small fraction of the amyloid precursor protein (APP) gives rise to Aβ. Here, we report that ∼10% of APP undergoes a post-translational lipid modification called palmitoylation. We identified the palmitoylation sites in APP at Cys¹⁸⁶ and Cys¹⁸⁷. Surprisingly, point mutations introduced into these cysteines caused nearly complete ER retention of APP. Thus, either APP palmitoylation or disulfide bridges involving these Cys residues appear to be required for ER exit of APP. In later compartments, palmitoylated APP (palAPP) was specifically enriched in lipid rafts. In vitro BACE1 cleavage assays using cell or mouse brain lipid rafts showed that APP palmitoylation enhanced BACE1-mediated processing of APP. Interestingly, we detected an age-dependent increase in endogenous mouse brain palAPP levels. Overexpression of selected DHHC palmitoyl acyltransferases increased palmitoylation of APP and doubled Aβ production, while two palmitoylation inhibitors reduced palAPP levels and APP processing. We have found previously that acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibition led to impaired APP processing. Here we demonstrate that pharmacological inhibition or genetic inactivation of ACAT decrease lipid raft palAPP levels by up to 76%, likely resulting in impaired APP processing. Together, our results indicate that APP palmitoylation enhances amyloidogenic processing by targeting APP to lipid rafts and enhancing its BACE1-mediated cleavage. Thus, inhibition of palAPP formation by ACAT or specific palmitoylation inhibitors would appear to be a valid strategy for prevention and/or treatment of AD.
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Windisch M, Flunkert S, Havas D, Hutter-Paier B. Commentary to the recently published review "Drug pipeline in neurodegeneration based on transgenic mice models of Alzheimer's disease" by Li, Evrahimi and Schluesener. Ageing Res. Rev. 2013 Jan;12(1):116-40. Ageing Res Rev 2013; 12:852-4. [PMID: 23851053 DOI: 10.1016/j.arr.2013.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 12/01/2022]
Abstract
Li and colleagues summarized the most frequently used Alzheimer's disease (AD) mouse models available for drug testing and the mediating effects of the different compounds. With almost 300 cited publications, authors present the research community's effort of the last 10 years in finding a new drug for the treatment of AD. Some of the transgenic mouse lines mentioned by Li and colleagues are discussed only very briefly. Since we are convinced that a couple of these models indeed have a great value for AD research and the development of new AD drugs we will subsequently describe a few of them in more detail. A suitable mouse model of AD does not only have to mimic major hallmarks of AD that are modifiable by different test substances as mentioned by the authors; they also have to be translational to clinical trials in humans. For the following discussion, we will therefore also include information on clinical trials of drugs previously tested in the different transgenic mice.
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Affiliation(s)
- M Windisch
- QPS Austria GmbH, Parkring 12, 8074 Grambach, Austria.
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Urano Y, Ochiai S, Noguchi N. Suppression of amyloid‐β production by 24S‐hydroxycholesterol
via
inhibition of intracellular amyloid precursor protein trafficking. FASEB J 2013; 27:4305-15. [DOI: 10.1096/fj.13-231456] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yasuomi Urano
- Department of Medical Life SystemsFaculty of Medical and Life SciencesDoshisha UniversityKyotoJapan
| | - Sachika Ochiai
- Department of Medical Life SystemsFaculty of Medical and Life SciencesDoshisha UniversityKyotoJapan
| | - Noriko Noguchi
- Department of Medical Life SystemsFaculty of Medical and Life SciencesDoshisha UniversityKyotoJapan
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Schon EA, Area-Gomez E. Mitochondria-associated ER membranes in Alzheimer disease. Mol Cell Neurosci 2013; 55:26-36. [DOI: 10.1016/j.mcn.2012.07.011] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 01/03/2023] Open
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Acat1 knockdown gene therapy decreases amyloid-β in a mouse model of Alzheimer's disease. Mol Ther 2013; 21:1497-506. [PMID: 23774792 DOI: 10.1038/mt.2013.118] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 05/01/2013] [Indexed: 12/13/2022] Open
Abstract
Both genetic inactivation and pharmacological inhibition of the cholesteryl ester synthetic enzyme acyl-CoA:cholesterol acyltransferase 1 (ACAT1) have shown benefit in mouse models of Alzheimer's disease (AD). In this study, we aimed to test the potential therapeutic applications of adeno-associated virus (AAV)-mediated Acat1 gene knockdown in AD mice. We constructed recombinant AAVs expressing artificial microRNA (miRNA) sequences, which targeted Acat1 for knockdown. We demonstrated that our AAVs could infect cultured mouse neurons and glia and effectively knockdown ACAT activity in vitro. We next delivered the AAVs to mouse brains neurosurgically, and demonstrated that Acat1-targeting AAVs could express viral proteins and effectively diminish ACAT activity in vivo, without inducing appreciable inflammation. We delivered the AAVs to the brains of 10-month-old AD mice and analyzed the effects on the AD phenotype at 12 months of age. Acat1-targeting AAV delivered to the brains of AD mice decreased the levels of brain amyloid-β and full-length human amyloid precursor protein (hAPP), to levels similar to complete genetic ablation of Acat1. This study provides support for the potential therapeutic use of Acat1 knockdown gene therapy in AD.
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Hayes CD, Dey D, Palavicini JP, Wang H, Patkar KA, Minond D, Nefzi A, Lakshmana MK. Striking reduction of amyloid plaque burden in an Alzheimer's mouse model after chronic administration of carmustine. BMC Med 2013; 11:81. [PMID: 23531149 PMCID: PMC3655051 DOI: 10.1186/1741-7015-11-81] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 03/26/2013] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Currently available therapies for Alzheimer's disease (AD) do not treat the underlying cause of AD. Anecdotal observations in nursing homes from multiple studies strongly suggest an inverse relationship between cancer and AD. Therefore, we reasoned that oncology drugs may be effective against AD. METHODS We screened a library of all the FDA-approved oncology drugs and identified bis-chloroethylnitrosourea (BCNU or carmustine) as an effective amyloid beta (Aβ) reducing compound. To quantify Aβ levels, Chinese hamster ovary (CHO) cells stably expressing amyloid precursor protein 751WT (APP751WT) called 7WD10 cells were exposed to different concentrations of BCNU for 48 hours and the conditioned media were collected. To detect Aβ the conditioned media were immunoprecipitated with Ab9 antibody and subjected to immunoblot detection. Amyloid plaques were quantified in the brains of a mouse model of AD after chronic exposure to BCNU by thoflavin S staining. RESULTS BCNU decreased normalized levels of Aβ starting from 5 μM by 39% (P < 0.05), 10 μM by 51% (P < 0.01) and 20 μM by 63% (P < 0.01) in CHO cells compared to a control group treated with butyl amine, a structural derivative of BCNU. Interestingly, soluble amyloid precursor protein α (sAPPα) levels were increased to 167% (P < 0.01) at 0.5 μM, 186% (P < 0.05) at 1 μM, 204% (P < 0.01) at 5 μM and 152% (P < 0.05) at 10 μM compared to untreated cells. We also tested the effects of 12 structural derivatives of BCNU on Aβ levels, but none of them were as potent as BCNU. BCNU treatment at 5 μM led to an accumulation of immature APP at the cell surface resulting in an increased ratio of surface to total APP by 184% for immature APP, but no change in mature APP. It is also remarkable that BCNU reduced Aβ generation independent of secretases which were not altered up to 40 μM. Interestingly, levels of transforming growth factor beta (TGFβ) were increased at 5 μM (43%, P < 0.05), 10 μM (73%, P < 0.01) and 20 μM (92%, P < 0.001). Most significantly, cell culture results were confirmed in vivo after chronic administration of BCNU at 0.5 mg/kg which led to the reduction of Aβ40 by 75% and amyloid plaque burden by 81%. Conversely, the levels of sAPPα were increased by 45%. CONCLUSIONS BCNU reduces Aβ generation and plaque burden at non-toxic concentrations possibly through altered intracellular trafficking and processing of APP. Taken together these data provided unequivocal evidence that BCNU is a potent secretase-sparing anti-Aβ drug. See related commentary article here http://www.biomedcentral.com/1741-7015/11/82.
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Affiliation(s)
- Crystal D Hayes
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, SW Village Parkway 11350, Port Saint Lucie, FL 34987, USA
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Poston CN, Krishnan SC, Bazemore-Walker CR. In-depth proteomic analysis of mammalian mitochondria-associated membranes (MAM). J Proteomics 2013; 79:219-30. [DOI: 10.1016/j.jprot.2012.12.018] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/12/2012] [Accepted: 12/26/2012] [Indexed: 12/25/2022]
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Reiss AB, Voloshyna I. Regulation of cerebral cholesterol metabolism in Alzheimer disease. J Investig Med 2012; 60:576-82. [PMID: 22367100 DOI: 10.2310/jim.0b013e318246d973] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alzheimer disease (AD) is an age-related neurodegenerative disorder that manifests as a progressive loss of memory and deterioration of higher cognitive functions. Alzheimer disease is characterized by accumulation in the brain of the β-amyloid peptide generated by β- and γ-secretase processing of amyloid precursor protein. Epidemiological studies have linked elevated plasma cholesterol and lipoprotein levels in midlife with AD development. Cholesterol-fed animal models exhibit neuropathologic features of AD including accumulation of β-amyloid peptide. Specific isoforms of the cholesterol transporter apolipoprotein E are associated with susceptibility to AD. Although multiple lines of evidence indicate a role for cholesterol in AD, the exact impact and mechanisms involved remain largely unknown. This review summarizes the current state of our knowledge of the influence of cholesterol and lipid pathways in AD pathogenesis in vitro and in vivo.
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Affiliation(s)
- Allison B Reiss
- Winthrop Research Institute, Department of Medicine, Winthrop University Hospital, Mineola, NY 11501, USA.
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Upregulated function of mitochondria-associated ER membranes in Alzheimer disease. EMBO J 2012; 31:4106-23. [PMID: 22892566 PMCID: PMC3492725 DOI: 10.1038/emboj.2012.202] [Citation(s) in RCA: 476] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 06/28/2012] [Indexed: 12/12/2022] Open
Abstract
Alzheimer disease (AD) associated (gamma)-secretase components presenilin-1 and -2 accumulate in MAM, an LR-like ER subcompartment connected to mitochondria. MAM function increases in patients with familial or sporadic AD and may be linked to AD pathogenesis. Alzheimer disease (AD) is associated with aberrant processing of the amyloid precursor protein (APP) by γ-secretase, via an unknown mechanism. We recently showed that presenilin-1 and -2, the catalytic components of γ-secretase, and γ-secretase activity itself, are highly enriched in a subcompartment of the endoplasmic reticulum (ER) that is physically and biochemically connected to mitochondria, called mitochondria-associated ER membranes (MAMs). We now show that MAM function and ER–mitochondrial communication—as measured by cholesteryl ester and phospholipid synthesis, respectively—are increased significantly in presenilin-mutant cells and in fibroblasts from patients with both the familial and sporadic forms of AD. We also show that MAM is an intracellular detergent-resistant lipid raft (LR)-like domain, consistent with the known presence of presenilins and γ-secretase activity in rafts. These findings may help explain not only the aberrant APP processing but also a number of other biochemical features of AD, including altered lipid metabolism and calcium homeostasis. We propose that upregulated MAM function at the ER–mitochondrial interface, and increased cross-talk between these two organelles, may play a hitherto unrecognized role in the pathogenesis of AD.
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Abstract
Alzheimer disease (AD) is an age-related neurodegenerative disorder that manifests as a progressive loss of memory and deterioration of higher cognitive functions. Alzheimer disease is characterized by accumulation in the brain of the β-amyloid peptide generated by β- and γ-secretase processing of amyloid precursor protein. Epidemiological studies have linked elevated plasma cholesterol and lipoprotein levels in midlife with AD development. Cholesterol-fed animal models exhibit neuropathologic features of AD including accumulation of β-amyloid peptide. Specific isoforms of the cholesterol transporter apolipoprotein E are associated with susceptibility to AD. Although multiple lines of evidence indicate a role for cholesterol in AD, the exact impact and mechanisms involved remain largely unknown. This review summarizes the current state of our knowledge of the influence of cholesterol and lipid pathways in AD pathogenesis in vitro and in vivo.
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Affiliation(s)
- Allison B Reiss
- Winthrop Research Institute, Department of Medicine, Winthrop University Hospital, Mineola, NY 11501, USA.
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Activation of Liver X Receptor Decreases BACE1 Expression and Activity by Reducing Membrane Cholesterol Levels. Neurochem Res 2011; 36:1910-21. [DOI: 10.1007/s11064-011-0513-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2011] [Indexed: 11/26/2022]
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Askarova S, Yang X, Lee JCM. Impacts of membrane biophysics in Alzheimer's disease: from amyloid precursor protein processing to aβ Peptide-induced membrane changes. Int J Alzheimers Dis 2011; 2011:134971. [PMID: 21547213 PMCID: PMC3087431 DOI: 10.4061/2011/134971] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/30/2010] [Accepted: 01/21/2011] [Indexed: 12/11/2022] Open
Abstract
An increasing amount of evidence supports the notion that cytotoxic effects of amyloid-β peptide (Aβ), the main constituent of senile plaques in Alzheimer's disease (AD), are strongly associated with its ability to interact with membranes of neurons and other cerebral cells. Aβ is derived from amyloidogenic cleavage of amyloid precursor protein (AβPP) by β- and γ-secretase. In the nonamyloidogenic pathway, AβPP is cleaved by α-secretases. These two pathways compete with each other, and enhancing the non-amyloidogenic pathway has been suggested as a potential pharmacological approach for the treatment of AD. Since AβPP, α-, β-, and γ-secretases are membrane-associated proteins, AβPP processing and Aβ production can be affected by the membrane composition and properties. There is evidence that membrane composition and properties, in turn, play a critical role in Aβ cytotoxicity associated with its conformational changes and aggregation into oligomers and fibrils. Understanding the mechanisms leading to changes in a membrane's biophysical properties and how they affect AβPP processing and Aβ toxicity should prove to provide new therapeutic strategies for prevention and treatment of AD.
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Affiliation(s)
- Sholpan Askarova
- Department of Biological Engineering, University of Missouri, Columbia, MO 65211, USA
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Fujimoto M, Hayashi T. New Insights into the Role of Mitochondria-Associated Endoplasmic Reticulum Membrane. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:73-117. [DOI: 10.1016/b978-0-12-386033-0.00002-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Huttunen HJ, Havas D, Peach C, Barren C, Duller S, Xia W, Frosch MP, Hutter-Paier B, Windisch M, Kovacs DM. The acyl-coenzyme A: cholesterol acyltransferase inhibitor CI-1011 reverses diffuse brain amyloid pathology in aged amyloid precursor protein transgenic mice. J Neuropathol Exp Neurol 2010; 69:777-88. [PMID: 20613640 PMCID: PMC2918281 DOI: 10.1097/nen.0b013e3181e77ed9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cerebral accumulation of amyloid-beta (Abeta) is characteristic of Alzheimer disease and of amyloid precursor protein (APP) transgenic mice. Here, we assessed the efficacy of CI-1011, an inhibitor of acyl-coenzyme A:cholesterol acyltransferase, which is suitable for clinical use, in reducing amyloid pathology in both young (6.5 months old) and aged (16 months old) human APP transgenic mice. Treatment of young animals with CI-1011 decreased amyloid plaque load in the cortex and hippocampus and reduced the levels of insoluble Abeta40 and Abeta42 and C-terminal fragments of APP in brain extracts. In aged mice, CI-1011 specifically reduced diffuse amyloid plaques with a minor effect on thioflavin S-positive dense-core plaques. Reduced diffusible amyloid was accompanied by suppression of astrogliosis and enhanced microglial activation. Collectively, these data suggest that CI-1011 treatment reduces amyloid burden in human APP mice by limiting generation and increasing clearance of diffusible Abeta.
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Affiliation(s)
- Henri J. Huttunen
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Daniel Havas
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Camilla Peach
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Cory Barren
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Stephan Duller
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Weiming Xia
- Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Matthew P. Frosch
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Birgit Hutter-Paier
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Manfred Windisch
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Dora M. Kovacs
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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Chang TY, Chang CCY, Bryleva E, Rogers MA, Murphy SR. Neuronal cholesterol esterification by ACAT1 in Alzheimer's disease. IUBMB Life 2010; 62:261-7. [PMID: 20101629 DOI: 10.1002/iub.305] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cholesterol has been implicated in various neurodegenerative diseases. Here we review the connection between cholesterol and Alzheimer's disease (AD), focusing on a recent study that links neuronal cholesterol esterification with biosynthesis of 24(S)-hydroxycholesterol and the fate of human amyloid precursor protein in a mouse model of AD. We also briefly evaluate the potential of ACAT1 as a drug target for AD.
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Affiliation(s)
- Ta-Yuan Chang
- Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.
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Bhattacharyya R, Kovacs DM. ACAT inhibition and amyloid beta reduction. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:960-5. [PMID: 20398792 DOI: 10.1016/j.bbalip.2010.04.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/01/2010] [Accepted: 04/02/2010] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder. Accumulation and deposition of the beta-amyloid (Abeta) peptide generated from its larger amyloid precursor protein (APP) is one of the pathophysiological hallmarks of AD. Intracellular cholesterol was shown to regulate Abeta production. Recent genetic and biochemical studies indicate that not only the amount, but also the distribution of intracellular cholesterol is critical to regulate Abeta generation. Acyl-coenzyme A: cholesterol acyl-transferase (ACAT) is a family of enzymes that regulates the cellular distribution of cholesterol by converting membrane cholesterol into hydrophobic cholesteryl esters for cholesterol storage and transport. Using pharmacological inhibitors and transgenic animal models, we and others have identified ACAT1 as a potential therapeutic target to lower Abeta generation and accumulation. Here we discuss data focusing on ACAT inhibition as an effective strategy for the prevention and treatment of AD.
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Affiliation(s)
- Raja Bhattacharyya
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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Burns MP, Rebeck GW. Intracellular cholesterol homeostasis and amyloid precursor protein processing. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:853-9. [PMID: 20304094 DOI: 10.1016/j.bbalip.2010.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/03/2010] [Accepted: 03/04/2010] [Indexed: 01/11/2023]
Abstract
Many preclinical and clinical studies have implied a role for cholesterol in the pathogenesis of Alzheimer's disease (AD). In this review we will discuss the movement of intracellular cholesterol and how normal distribution, transport, and export of cholesterol are vital for regulation of the AD related protein, Abeta. We focus on cholesterol distribution in the plasma membrane, transport through the endosomal/lysosomal system, control of cholesterol intracellular signaling at the endoplasmic reticulum and Golgi, the HMG-CoA reductase pathway and finally export of cholesterol from the cell.
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Affiliation(s)
- Mark P Burns
- Georgetown University Medical Center, Department of Neuroscience, Washington, DC 20057, USA.
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ACAT1 gene ablation increases 24(S)-hydroxycholesterol content in the brain and ameliorates amyloid pathology in mice with AD. Proc Natl Acad Sci U S A 2010; 107:3081-6. [PMID: 20133765 DOI: 10.1073/pnas.0913828107] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cholesterol metabolism has been implicated in the pathogenesis of several neurodegenerative diseases, including the abnormal accumulation of amyloid-beta, one of the pathological hallmarks of Alzheimer disease (AD). Acyl-CoA:cholesterol acyltransferases (ACAT1 and ACAT2) are two enzymes that convert free cholesterol to cholesteryl esters. ACAT inhibitors have recently emerged as promising drug candidates for AD therapy. However, how ACAT inhibitors act in the brain has so far remained unclear. Here we show that ACAT1 is the major functional isoenzyme in the mouse brain. ACAT1 gene ablation (A1-) in triple transgenic (i.e., 3XTg-AD) mice leads to more than 60% reduction in full-length human APPswe as well as its proteolytic fragments, and ameliorates cognitive deficits. At 4 months of age, A1- causes a 32% content increase in 24-hydroxycholesterol (24SOH), the major oxysterol in the brain. It also causes a 65% protein content decrease in HMG-CoA reductase (HMGR) and a 28% decrease in sterol synthesis rate in AD mouse brains. In hippocampal neurons, A1- causes an increase in the 24SOH synthesis rate; treating hippocampal neuronal cells with 24SOH causes rapid declines in hAPP and in HMGR protein levels. A model is provided to explain our findings: in neurons, A1- causes increases in cholesterol and 24SOH contents in the endoplasmic reticulum, which cause reductions in hAPP and HMGR protein contents and lead to amelioration of amyloid pathology. Our study supports the potential of ACAT1 as a therapeutic target for treating certain forms of AD.
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Ray B, Banerjee PK, Greig NH, Lahiri DK. Memantine treatment decreases levels of secreted Alzheimer's amyloid precursor protein (APP) and amyloid beta (A beta) peptide in the human neuroblastoma cells. Neurosci Lett 2009; 470:1-5. [PMID: 19948208 DOI: 10.1016/j.neulet.2009.11.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 01/05/2023]
Abstract
Memantine, an uncompetitive NMDA receptor antagonist, is a FDA-approved drug used for the treatment of moderate-to-severe Alzheimer's disease (AD). Several studies have documented protective roles of memantine against amyloid beta (A beta) peptide-mediated damage to neurons in both in vitro and in vivo models. Memantine is also effective in reducing amyloid burden in the brain of APP transgenic mice. However, the exact mechanism by which memantine provides protection against A beta-mediated neurodegenerative cascade, including APP metabolism, remains to be elucidated. Herein, we investigated the effect of memantine on levels of the secreted form of A beta precursor protein (APP), secreted A beta and cell viability markers under short/acute conditions. We treated neuronal SK-N-SH cells with 10 microM memantine and measured levels of secreted total APP (sAPP), APP alpha isoform and A beta((1-40)) in a time dependent manner for up to 24h. Memantine significantly decreased the levels of the secreted form of sAPP, sAPP alpha and A beta((1-40)) compared to vehicle treated cells. This change started as early as 8h and continued for up to 24h of drug treatment. Unlike sAPP, a slight non-significant increase in total intracellular APP level was observed in 24-h treated memantine cells. Taken together, these results suggest a role for memantine in the transport or trafficking of APP molecules away from the site of their proteolytic cleavage by the secretase enzymes. Such a novel property of memantine warrants further study to define its therapeutic utility.
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Affiliation(s)
- Balmiki Ray
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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