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Dunot J, Ribera A, Pousinha PA, Marie H. Spatiotemporal insights of APP function. Curr Opin Neurobiol 2023; 82:102754. [PMID: 37542943 DOI: 10.1016/j.conb.2023.102754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/29/2023] [Accepted: 07/07/2023] [Indexed: 08/07/2023]
Abstract
The amyloid-β precursor protein (APP) is a ubiquitous protein with a strong genetic link to Alzheimer's disease. Although the protein was identified more than forty years ago, its physiological function is still unclear. In recent years, advances in technology have allowed researchers to tackle APP functions in greater depth. In this review, we discuss the latest research pertaining to APP functions from development to aging. We also address the different roles that APP could play in specific types of cells of the central and peripheral nervous system and in other organs of the body. We argue that, until we fully identify the functions of APP in space and time, we will be missing important pieces of the puzzle to solve its pathological implication in Alzheimer's disease and beyond.
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Affiliation(s)
- Jade Dunot
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France. https://twitter.com/DunotJade
| | - Aurore Ribera
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France. https://twitter.com/aurore_et_al_
| | - Paula A Pousinha
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France.
| | - Hélène Marie
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France.
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2
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Zhang WB, Huang Y, Guo XR, Zhang MQ, Yuan XS, Zu HB. DHCR24 reverses Alzheimer's disease-related pathology and cognitive impairment via increasing hippocampal cholesterol levels in 5xFAD mice. Acta Neuropathol Commun 2023; 11:102. [PMID: 37344916 DOI: 10.1186/s40478-023-01593-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 05/30/2023] [Indexed: 06/23/2023] Open
Abstract
Accumulating evidences reveal that cellular cholesterol deficiency could trigger the onset of Alzheimer's disease (AD). As a key regulator, 24-dehydrocholesterol reductase (DHCR24) controls cellular cholesterol homeostasis, which was found to be downregulated in AD vulnerable regions and involved in AD-related pathological activities. However, DHCR24 as a potential therapeutic target for AD remains to be identified. In present study, we demonstrated the role of DHCR24 in AD by employing delivery of adeno-associated virus carrying DHCR24 gene into the hippocampus of 5xFAD mice. Here, we found that 5xFAD mice had lower levels of cholesterol and DHCR24 expression, and the cholesterol loss was alleviated by DHCR24 overexpression. Surprisingly, the cognitive impairment of 5xFAD mice was significantly reversed after DHCR24-based gene therapy. Moreover, we revealed that DHCR24 knock-in successfully prevented or reversed AD-related pathology in 5xFAD mice, including amyloid-β deposition, synaptic injuries, autophagy, reactive astrocytosis, microglial phagocytosis and apoptosis. In conclusion, our results firstly demonstrated that the potential value of DHCR24-mediated regulation of cellular cholesterol level as a promising treatment for AD.
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Affiliation(s)
- Wen-Bin Zhang
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China
| | - Yue Huang
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China
| | - Xiao-Rou Guo
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China
| | - Meng-Qi Zhang
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China
| | - Xiang-Shan Yuan
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China.
- Department of Anatomy and Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
- State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Heng-Bing Zu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No.1508 Long-Hang Road, Jinshan District, Shanghai, 201508, China.
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3
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Van Acker ZP, Perdok A, Hellemans R, North K, Vorsters I, Cappel C, Dehairs J, Swinnen JV, Sannerud R, Bretou M, Damme M, Annaert W. Phospholipase D3 degrades mitochondrial DNA to regulate nucleotide signaling and APP metabolism. Nat Commun 2023; 14:2847. [PMID: 37225734 DOI: 10.1038/s41467-023-38501-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
Phospholipase D3 (PLD3) polymorphisms are linked to late-onset Alzheimer's disease (LOAD). Being a lysosomal 5'-3' exonuclease, its neuronal substrates remained unknown as well as how a defective lysosomal nucleotide catabolism connects to AD-proteinopathy. We identified mitochondrial DNA (mtDNA) as a major physiological substrate and show its manifest build-up in lysosomes of PLD3-defective cells. mtDNA accretion creates a degradative (proteolytic) bottleneck that presents at the ultrastructural level as a marked abundance of multilamellar bodies, often containing mitochondrial remnants, which correlates with increased PINK1-dependent mitophagy. Lysosomal leakage of mtDNA to the cytosol activates cGAS-STING signaling that upregulates autophagy and induces amyloid precursor C-terminal fragment (APP-CTF) and cholesterol accumulation. STING inhibition largely normalizes APP-CTF levels, whereas an APP knockout in PLD3-deficient backgrounds lowers STING activation and normalizes cholesterol biosynthesis. Collectively, we demonstrate molecular cross-talks through feedforward loops between lysosomal nucleotide turnover, cGAS-STING and APP metabolism that, when dysregulated, result in neuronal endolysosomal demise as observed in LOAD.
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Affiliation(s)
- Zoë P Van Acker
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Anika Perdok
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Ruben Hellemans
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Katherine North
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Inge Vorsters
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Cedric Cappel
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Marine Bretou
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Markus Damme
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium.
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium.
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4
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Montesinos J, Pera M, Larrea D, Guardia‐Laguarta C, Agrawal RR, Velasco KR, Yun TD, Stavrovskaya IG, Xu Y, Koo SY, Snead AM, Sproul AA, Area‐Gomez E. The Alzheimer's disease-associated C99 fragment of APP regulates cellular cholesterol trafficking. EMBO J 2020; 39:e103791. [PMID: 32865299 PMCID: PMC7560219 DOI: 10.15252/embj.2019103791] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 07/14/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
The link between cholesterol homeostasis and cleavage of the amyloid precursor protein (APP), and how this relationship relates to Alzheimer's disease (AD) pathogenesis, is still unknown. Cellular cholesterol levels are regulated through crosstalk between the plasma membrane (PM), where most cellular cholesterol resides, and the endoplasmic reticulum (ER), where the protein machinery that regulates cholesterol levels resides. The intracellular transport of cholesterol from the PM to the ER is believed to be activated by a lipid-sensing peptide(s) in the ER that can cluster PM-derived cholesterol into transient detergent-resistant membrane domains (DRMs) within the ER, also called the ER regulatory pool of cholesterol. When formed, these cholesterol-rich domains in the ER maintain cellular homeostasis by inducing cholesterol esterification as a mechanism of detoxification while attenuating its de novo synthesis. In this manuscript, we propose that the 99-aa C-terminal fragment of APP (C99), when delivered to the ER for cleavage by γ-secretase, acts as a lipid-sensing peptide that forms regulatory DRMs in the ER, called mitochondria-associated ER membranes (MAM). Our data in cellular AD models indicates that increased levels of uncleaved C99 in the ER, an early phenotype of the disease, upregulates the formation of these transient DRMs by inducing the internalization of extracellular cholesterol and its trafficking from the PM to the ER. These results suggest a novel role for C99 as a mediator of cholesterol disturbances in AD, potentially explaining early hallmarks of the disease.
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Affiliation(s)
- Jorge Montesinos
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
| | - Marta Pera
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
- Present address:
Basic Sciences DepartmentFaculty of Medicine and Health SciencesUniversitat Internacional de CatalunyaBarcelonaSpain
| | - Delfina Larrea
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
| | | | - Rishi R Agrawal
- Institute of Human NutritionColumbia University Irving Medical CenterNew YorkNYUSA
| | - Kevin R Velasco
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
| | - Taekyung D Yun
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
| | | | - Yimeng Xu
- Biomarkers Core LaboratoryColumbia University Irving Medical CenterNew YorkNYUSA
| | - So Yeon Koo
- Taub Institute for Research on Alzheimer's Disease and the Aging BrainColumbia University Irving Medical CenterNew YorkNYUSA
| | - Amanda M Snead
- Taub Institute for Research on Alzheimer's Disease and the Aging BrainColumbia University Irving Medical CenterNew YorkNYUSA
| | - Andrew A Sproul
- Taub Institute for Research on Alzheimer's Disease and the Aging BrainColumbia University Irving Medical CenterNew YorkNYUSA
- Department of Pathology and Cell BiologyColumbia University Irving Medical CenterNew YorkNYUSA
| | - Estela Area‐Gomez
- Department of NeurologyColumbia University Irving Medical CenterNew YorkNYUSA
- Institute of Human NutritionColumbia University Irving Medical CenterNew YorkNYUSA
- Taub Institute for Research on Alzheimer's Disease and the Aging BrainColumbia University Irving Medical CenterNew YorkNYUSA
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5
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Bandres-Ciga S, Noyce AJ, Hemani G, Nicolas A, Calvo A, Mora G, Tienari PJ, Stone DJ, Nalls MA, Singleton AB, Chiò A, Traynor BJ. Shared polygenic risk and causal inferences in amyotrophic lateral sclerosis. Ann Neurol 2019; 85:470-481. [PMID: 30723964 PMCID: PMC6450729 DOI: 10.1002/ana.25431] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To identify shared polygenic risk and causal associations in amyotrophic lateral sclerosis (ALS). METHODS Linkage disequilibrium score regression and Mendelian randomization were applied in a large-scale, data-driven manner to explore genetic correlations and causal relationships between >700 phenotypic traits and ALS. Exposures consisted of publicly available genome-wide association studies (GWASes) summary statistics from MR Base and LD-hub. The outcome data came from the recently published ALS GWAS involving 20,806 cases and 59,804 controls. Multivariate analyses, genetic risk profiling, and Bayesian colocalization analyses were also performed. RESULTS We have shown, by linkage disequilibrium score regression, that ALS shares polygenic risk genetic factors with a number of traits and conditions, including positive correlations with smoking status and moderate levels of physical activity, and negative correlations with higher cognitive performance, higher educational attainment, and light levels of physical activity. Using Mendelian randomization, we found evidence that hyperlipidemia is a causal risk factor for ALS and localized putative functional signals within loci of interest. INTERPRETATION Here, we have developed a public resource (https://lng-nia.shinyapps.io/mrshiny) which we hope will become a valuable tool for the ALS community, and that will be expanded and updated as new data become available. Shared polygenic risk exists between ALS and educational attainment, physical activity, smoking, and tenseness/restlessness. We also found evidence that elevated low-desnity lipoprotein cholesterol is a causal risk factor for ALS. Future randomized controlled trials should be considered as a proof of causality. Ann Neurol 2019;85:470-481.
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Affiliation(s)
- Sara Bandres-Ciga
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD.,Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, Spain
| | - Alastair J Noyce
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, United Kingdom.,Department of Clinical and Movement Neurosciences, University College London, Institute of Neurology, London, United Kingdom
| | - Gibran Hemani
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
| | - Aude Nicolas
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD
| | - Andrea Calvo
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy
| | - Gabriele Mora
- ALS Center, Istituti Clinici Scientifici Maugeri, IRCCS, Milan, Italy
| | | | | | - Pentti J Tienari
- Department of Neurology, Helsinki University Hospital and Molecular Neurology Programme, Biomedicum, University of Helsinki, Helsinki, Finland
| | - David J Stone
- Genetics and Pharmacogenomics, Merck Research Laboratories, Merck & Co., Inc., West Point, PA
| | - Mike A Nalls
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD.,Data Tecnica International, Glen Echo, MD
| | - Andrew B Singleton
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD
| | - Adriano Chiò
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.,Institute of Cognitive Sciences and Technologies, C.N.R, Rome, Italy.,Azienda Ospedaliero Universitaria Città della Salute e della Scienza, Turin, Italy
| | - Bryan J Traynor
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD.,Department of Neurology, Johns Hopkins University, Baltimore, MD
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6
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Wang C, Zhao F, Shen K, Wang W, Siedlak SL, Lee HG, Phelix CF, Perry G, Shen L, Tang B, Yan R, Zhu X. The sterol regulatory element-binding protein 2 is dysregulated by tau alterations in Alzheimer disease. Brain Pathol 2019; 29:530-543. [PMID: 30515907 DOI: 10.1111/bpa.12691] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 11/28/2018] [Indexed: 01/12/2023] Open
Abstract
Disturbed neuronal cholesterol homeostasis has been observed in Alzheimer disease (AD) and contributes to the pathogenesis of AD. As the master switch of cholesterol biosynthesis, the sterol regulatory element-binding protein 2 (SREBP-2) translocates to the nucleus after cleavage/activation, but its expression and activation have not been studied in AD which is the focus of the current study. We found both a significant decrease in the nuclear translocation of N-terminal SREBP-2 accompanied by a significant accumulation of C-terminal SREBP-2 in NFT-containing pyramidal neurons in AD. N-terminal- SREBP-2 is also found in dystrophic neurites around plaques in AD brain. Western blot confirmed a significantly reduced nuclear translocation of mature SREBP-2 (mSREBP-2) in AD brain. Interestingly, reduced nuclear mSREBP-2 was only found in animal models of tauopathies such as 3XTg AD mice and P301L Tau Tg mice but not in CRND8 APP transgenic mice, suggesting that tau alterations likely are involved in the changes of mSREBP-2 distribution and activation in AD. Altogether, our study demonstrated disturbed SREBP-2 signaling in AD and related models, and proved for the first time that tau alterations contribute to disturbed cholesterol homeostasis in AD likely through modulation of nuclear mSREBP-2 translocation.
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Affiliation(s)
- Chunyu Wang
- Department of Neurology, The second Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.,Department of Pathology, Case Western Reserve University, Cleveland, OH
| | - Fanpeng Zhao
- Department of Pathology, Case Western Reserve University, Cleveland, OH
| | - Katie Shen
- Department of Pathology, Case Western Reserve University, Cleveland, OH
| | - Wenzhang Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH
| | - Sandra L Siedlak
- Department of Pathology, Case Western Reserve University, Cleveland, OH
| | - Hyoung-Gon Lee
- Department of Biology, College of Science, University of Texas at San Antonio, San Antonio, TX
| | - Clyde F Phelix
- Department of Biology, College of Science, University of Texas at San Antonio, San Antonio, TX
| | - George Perry
- Department of Biology, College of Science, University of Texas at San Antonio, San Antonio, TX
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Riqiang Yan
- Department of Neurosciences, University of Connecticut, Farmington, CT
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH
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7
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Serum noncholesterol sterols in Alzheimer's disease: the Helsinki Businessmen Study. Transl Res 2018; 202:120-128. [PMID: 30102918 DOI: 10.1016/j.trsl.2018.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022]
Abstract
Cerebral cholesterol metabolism is perturbed in late-onset Alzheimer's disease (AD), but whether also the extracerebral cholesterol metabolism is perturbed is not known. Thus, we studied whole-body cholesterol synthesis and absorption with serum noncholesterol sterols in men without AD (n = 114) or with (n = 18) "pure" AD (no concomitant atherosclerotic cardiovascular disease) in a long-term cohort (the Helsinki Businessmen Study) of home-dwelling older men without lipid-lowering drugs and on their habitual home diet. Serum lipids did not differ between AD and controls, but age was higher (78 ± 1 vs 74 ± 0.3 years, mean ± standard error, P < 0.001), age-adjusted plasma glucose concentration was lower (4.8 ± 0.3 vs 5.7 ± 0.1 mmol/L, P = 0.011), and APOE ε4 allele and frailty were more frequent in AD than in controls. Of the age and frailty-adjusted serum noncholesterol sterols desmosterol and lathosterol ratios to cholesterol reflecting cholesterol synthesis were lower in AD than in controls (eg, lathosterol 114 ± 12 vs 137 ± 5 102 µmol/mmol cholesterol, P = 0.004). Cholestanol ratio to cholesterol was higher in AD than in controls suggesting increased cholesterol absorption. lathosterol/sitosteroll ratio reflecting cholesterol metabolism was lower in AD than in controls (0.95 ± 0.28 vs 1.52 ± 0.11 102 µmol/mmol cholesterol, P = 0.027). In AD, plasma glucose correlated negatively with cholesterol synthesis, whereas in controls the correlation was positive. In conclusion, extracerebral cholesterol metabolism was altered in AD. This finding along with the low plasma glucose concentration and its paradoxical interaction with cholesterol synthesis opens new perspectives in the regulation of cholesterol metabolism and glucose homeostasis in AD.
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8
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DelBove CE, Deng XZ, Zhang Q. The Fate of Nascent APP in Hippocampal Neurons: A Live Cell Imaging Study. ACS Chem Neurosci 2018; 9:2225-2232. [PMID: 29869871 DOI: 10.1021/acschemneuro.8b00226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Amyloid precursor protein (APP) is closely associated with Alzheimer's disease (AD) because its proteolytic products form amyloid plaques and its mutations are linked to familial AD patients. As a membrane protein, APP is involved in neuronal development and plasticity. However, it remains unclear how nascent APP is distributed and transported to designated membrane compartments to execute its diverse functions. Here, we employed a dual-tagged APP fusion protein in combination with a synaptic vesicle marker to study the surface trafficking and cleavage of APP in hippocampal neurons immediately after its synthesis. Using long-term time-lapse imaging, we found that a considerable amount of nascent APP was directly transported to the somatodendritic surface, from which it propagates to distal neurites. Some APP in the plasma membrane was endocytosed and some was cleaved by α-secretase. Hence, we conclude that surface transportation of APP is a major step preceding its proteolytic processing and neuritic distribution.
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Affiliation(s)
- Claire E. DelBove
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, United States
| | - Xian-zhen Deng
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, United States
| | - Qi Zhang
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, United States
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9
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Fong LK, Yang MM, Dos Santos Chaves R, Reyna SM, Langness VF, Woodruff G, Roberts EA, Young JE, Goldstein LSB. Full-length amyloid precursor protein regulates lipoprotein metabolism and amyloid-β clearance in human astrocytes. J Biol Chem 2018; 293:11341-11357. [PMID: 29858247 DOI: 10.1074/jbc.ra117.000441] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 05/11/2018] [Indexed: 02/05/2023] Open
Abstract
Mounting evidence suggests that alterations in cholesterol homeostasis are involved in Alzheimer's disease (AD) pathogenesis. Amyloid precursor protein (APP) or multiple fragments generated by proteolytic processing of APP have previously been implicated in the regulation of cholesterol metabolism. However, the physiological function of APP in regulating lipoprotein homeostasis in astrocytes, which are responsible for de novo cholesterol biosynthesis and regulation in the brain, remains unclear. To address this, here we used CRISPR/Cas9 genome editing to generate isogenic APP-knockout (KO) human induced pluripotent stem cells (hiPSCs) and differentiated them into human astrocytes. We found that APP-KO astrocytes have reduced cholesterol and elevated levels of sterol regulatory element-binding protein (SREBP) target gene transcripts and proteins, which were both downstream consequences of reduced lipoprotein endocytosis. To elucidate which APP fragments regulate cholesterol homeostasis and to examine whether familial AD mutations in APP affect lipoprotein metabolism, we analyzed an isogenic allelic series harboring the APP Swedish and APP V717F variants. Only astrocytes homozygous for the APP Swedish (APPSwe/Swe) mutation, which had reduced full-length APP (FL APP) due to increased β-secretase cleavage, recapitulated the APP-KO phenotypes. Astrocytic internalization of β-amyloid (Aβ), another ligand for low-density lipoprotein (LDL) receptors, was also impaired in APP-KO and APPSwe/Swe astrocytes. Finally, impairing cleavage of FL APP through β-secretase inhibition in APPSwe/Swe astrocytes reversed the LDL and Aβ endocytosis defects. In conclusion, FL APP is involved in the endocytosis of LDL receptor ligands and is required for proper cholesterol homeostasis and Aβ clearance in human astrocytes.
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Affiliation(s)
- Lauren K Fong
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Max M Yang
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Rodrigo Dos Santos Chaves
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Sol M Reyna
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Vanessa F Langness
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Grace Woodruff
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Elizabeth A Roberts
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093
| | - Jessica E Young
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Department of Pathology and Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington 98195
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093; Department of Neurosciences, University of California at San Diego, La Jolla, California 92093.
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10
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Wang Y, Zhang R, Tao C, Xu Z, Chen W, Wang C, Song L, Zheng J, Gao F. Blood-Brain Barrier Disruption and Perivascular Beta-Amyloid Accumulation in the Brain of Aged Rats with Spontaneous Hypertension: Evaluation with Dynamic Contrast-Enhanced Magnetic Resonance Imaging. Korean J Radiol 2018; 19:498-507. [PMID: 29713228 PMCID: PMC5904477 DOI: 10.3348/kjr.2018.19.3.498] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/23/2017] [Indexed: 02/05/2023] Open
Abstract
Objective Whether blood-brain barrier (BBB) disruption induced by chronic spontaneous hypertension is associated with beta-amyloid (Aβ) accumulation in the brain remains poorly understood. The purpose of this study was to investigate the relationship between BBB disruption and Aβ influx and accumulation in the brain of aged rats with chronic spontaneous hypertension. Materials and Methods Five aged spontaneously hypertensive rats (SHRs) and five age-matched normotensive Wistar-Kyoto (WKY) rats were studied. The volume transfer constant (Ktrans) obtained from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used to evaluate BBB permeability in the hippocampus and cortex in vivo. The BBB tight junctions, immunoglobulin G (IgG), Aβ, and amyloid precursor protein (APP) in the hippocampus and cortex were examined with immunohistochemistry. Results As compared with WKY rats, the Ktrans values in the hippocampus and cortex of the SHRs increased remarkably (0.316 ± 0.027 min-1 vs. 0.084 ± 0.017 min-1, p < 0.001 for hippocampus; 0.302 ± 0.072 min-1 vs. 0.052 ± 0.047 min-1, p < 0.001 for cortex). Dramatic occludin and zonula occludens-1 losses were detected in the hippocampus and cortex of SHRs, and obvious IgG exudation was found there. Dramatic Aβ accumulation was found and limited to the area surrounding the BBB, without extension to other parenchyma regions in the hippocampus and cortex of aged SHRs. Alternatively, differences in APP expression in the hippocampus and cortex were not significant. Conclusion Blood-brain barrier disruption is associated with Aβ influx and accumulation in the brain of aged rats with chronic spontaneous hypertension. DCE-MRI can be used as an effective method to investigated BBB damage.
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Affiliation(s)
- Yu Wang
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China.,Department of Radiology, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
| | - Ruzhi Zhang
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Chuanyuan Tao
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Ziqian Xu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Wei Chen
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Chunhua Wang
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Li Song
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis 63110, MO, USA
| | - Fabao Gao
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
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11
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Mäkelä M, Kaivola K, Valori M, Paetau A, Polvikoski T, Singleton AB, Traynor BJ, Stone DJ, Peuralinna T, Tienari PJ, Tanskanen M, Myllykangas L. Alzheimer risk loci and associated neuropathology in a population-based study (Vantaa 85+). NEUROLOGY-GENETICS 2018; 4:e211. [PMID: 29379882 PMCID: PMC5773846 DOI: 10.1212/nxg.0000000000000211] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 11/26/2017] [Indexed: 01/23/2023]
Abstract
Objective To test the association of distinct neuropathologic features of Alzheimer disease (AD) with risk loci identified in genome-wide association studies. Methods Vantaa 85+ is a population-based study that includes 601 participants aged ≥85 years, of which 256 were neuropathologically examined. We analyzed 29 AD risk loci in addition to APOE ε4, which was studied separately and used as a covariate. Genotyping was performed using a single nucleotide polymorphism (SNP) array (341 variants) and imputation (6,038 variants). Participants with Consortium to Establish a Registry for Alzheimer Disease (CERAD) (neuritic Aβ plaques) scores 0 (n = 65) vs score M + F (n = 171) and Braak (neurofibrillary tangle pathology) stages 0–II (n = 74) vs stages IV–VI (n = 119), and with capillary Aβ (CapAβ, n = 77) vs without (n = 179) were compared. Cerebral amyloid angiopathy (CAA) percentage was analyzed as a continuous variable. Results Altogether, 24 of the 29 loci were associated (at p < 0.05) with one or more AD-related neuropathologic features in either SNP array or imputation data. Fifteen loci associated with CERAD score, smallest p = 0.0002122, odds ratio (OR) 2.67 (1.58–4.49) at MEF2C locus. Fifteen loci associated with Braak stage, smallest p = 0.004372, OR 0.31 (0.14–0.69) at GAB2 locus. Twenty loci associated with CAA, smallest p = 7.17E-07, β 14.4 (8.88–20) at CR1 locus. Fifteen loci associated with CapAβ smallest p = 0.002594, OR 0.54 (0.37–0.81) at HLA-DRB1 locus. Certain loci associated with specific neuropathologic features. CASS4, CLU, and ZCWPW1 associated only with CAA, while TREM2 and HLA-DRB5 associated only with CapAβ. Conclusions AD risk loci differ in their association with neuropathologic features, and we show for the first time distinct risk loci for CAA and CapAβ.
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Affiliation(s)
- Mira Mäkelä
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Karri Kaivola
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Miko Valori
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Anders Paetau
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Tuomo Polvikoski
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Andrew B Singleton
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Bryan J Traynor
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - David J Stone
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Terhi Peuralinna
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Pentti J Tienari
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Maarit Tanskanen
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
| | - Liisa Myllykangas
- Department of Pathology (M.M., A.E.P., M.T., L.M.), University of Helsinki, and Helsinki University Hospital, Finland; Molecular Neurology (K.K., M.V., T. Peuralinna, P.J.T.), Research Programs Unit, University of Helsinki, and Department of Neurology, Helsinki University Hospital, Finland; Institute of Neuroscience (T. Polvikoski), Newcastle University, United Kingdom; Laboratory of Neurogenetics (A.B.S., B.J.T.), National Institutes on Aging, NIH, Bethesda, MD; and Merck Research Laboratories (D.J.S.), Merck & Co., Inc., West Point, PA, USA
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12
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Membrane cholesterol depletion in cortical neurons highlights altered NMDA receptor functionality in a mouse model of amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2017; 1864:509-519. [PMID: 29154925 DOI: 10.1016/j.bbadis.2017.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/16/2017] [Accepted: 11/13/2017] [Indexed: 12/25/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a chronic neurodegenerative disease affecting upper and lower motor neurons, with unknown aetiology. Lipid rafts, cholesterol enriched microdomains of the plasma membrane, have been linked to neurodegenerative disorders like ALS. The NMDA-receptor subcellular localization in lipid rafts is known to play many roles, from modulating memory strength to neurotoxicity. In this study, performed on the widely used G93A mouse model of ALS, we have shown an equal content of total membrane cholesterol in Control and G93A cortical cultures. Moreover, by electrophysiological studies, we have recorded NMDA- and AMPA-evoked currents which were not significantly different between the two neuronal populations. To study the role of membrane cholesterol on glutamate receptor functionality, we have analysed NMDA and AMPA receptors following cholesterol membrane depletion by methyl-β-cyclodextrin (MβCD). Interestingly, MβCD chronic treatment has provoked a significant reduction of NMDA-evoked currents in both cellular populations which was dose- and time-dependent but significantly higher in ALS neurons compared to Control. The different MβCD effect on NMDA-evoked currents was not due to a different membrane receptor subunit composition but seemed to cause in both neuronal populations a NMDA receptor membrane redistribution. MβCD treatment effect was receptor-specific since no alterations in the two neuronal populations were detected on AMPA receptors. These results lead us to speculate for an altered proteomic composition of lipid rafts in cortical mutated neurons and suggest the need for further studies on the lipid rafts composition and on their interaction with membrane receptors in ALS cortices.
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13
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Olkkonen VM, Gylling H, Ikonen E. Plant sterols, cholesterol precursors and oxysterols: Minute concentrations-Major physiological effects. J Steroid Biochem Mol Biol 2017; 169:4-9. [PMID: 26733205 DOI: 10.1016/j.jsbmb.2015.12.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 01/28/2023]
Abstract
Non-cholesterol sterols are present in our body at very low concentrations as compared to cholesterol. Small changes in the structure of sterol molecules confer them highly distinct biological activities. The best-known example are steroid hormones derived from cholesterol. During the past decade, our knowledge of also other biomolecules related to or derived from cholesterol, particularly plant sterols, biosynthetic precursors of cholesterol, and oxysterols, has expanded rapidly. In this review article we recapitulate the latest insights into the properties and physiological activities of these non-cholesterol sterols, as well as their importance in disease processes and potential as diagnostic biomarkers.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, FI-00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, FI-00014 University of Helsinki, Finland.
| | - Helena Gylling
- University of Helsinki and Helsinki University Central Hospital, Internal Medicine, Helsinki FI-00029 HUS, Finland
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, FI-00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, FI-00014 University of Helsinki, Finland
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14
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Aberrant de novo cholesterogenesis: Clinical significance and implications. Clin Chim Acta 2015; 450:356-61. [PMID: 26386164 DOI: 10.1016/j.cca.2015.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/12/2015] [Accepted: 09/15/2015] [Indexed: 01/23/2023]
Abstract
Human cells can acquire cholesterol from the circulation but also have the ability to synthesize it via de novo cholesterogenesis (DC). Cholesterol absorption and de novo cholesterogenesis are the key processes that modulate cholesterol homeostasis in the human body. The endogenous biosynthesis of cholesterol substantially contributes to the whole-body cholesterol pool. Additionally, dysregulation of this pathway is associated with diverse medical conditions. The present review focuses on our current understanding of the cholesterogenic pathway and the various different factors regulating this pathway. It also highlights dysregulation of this pathway in various physiological and pathological conditions including cardiovascular diseases, type II diabetes, obesity and viral infections.
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15
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van der Kant R, Goldstein LSB. Cellular functions of the amyloid precursor protein from development to dementia. Dev Cell 2015; 32:502-15. [PMID: 25710536 DOI: 10.1016/j.devcel.2015.01.022] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Amyloid precursor protein (APP) is a key player in Alzheimer's disease (AD). The Aβ fragments of APP are the major constituent of AD-associated amyloid plaques, and mutations or duplications of the gene coding for APP can cause familial AD. Here we review the roles of APP in neuronal development, signaling, intracellular transport, and other aspects of neuronal homeostasis. We suggest that APP acts as a signaling nexus that transduces information about a range of extracellular conditions, including neuronal damage, to induction of intracellular signaling events. Subtle disruptions of APP signaling functions may be major contributors to AD-causing neuronal dysfunction.
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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.
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
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16
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Martín MG, Pfrieger F, Dotti CG. Cholesterol in brain disease: sometimes determinant and frequently implicated. EMBO Rep 2014; 15:1036-52. [PMID: 25223281 DOI: 10.15252/embr.201439225] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cholesterol is essential for neuronal physiology, both during development and in the adult life: as a major component of cell membranes and precursor of steroid hormones, it contributes to the regulation of ion permeability, cell shape, cell-cell interaction, and transmembrane signaling. Consistently, hereditary diseases with mutations in cholesterol-related genes result in impaired brain function during early life. In addition, defects in brain cholesterol metabolism may contribute to neurological syndromes, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD), and even to the cognitive deficits typical of the old age. In these cases, brain cholesterol defects may be secondary to disease-causing elements and contribute to the functional deficits by altering synaptic functions. In the first part of this review, we will describe hereditary and non-hereditary causes of cholesterol dyshomeostasis and the relationship to brain diseases. In the second part, we will focus on the mechanisms by which perturbation of cholesterol metabolism can affect synaptic function.
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Affiliation(s)
- Mauricio G Martín
- Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra (INIMEC-CONICET-UNC), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Frank Pfrieger
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Carlos G Dotti
- Centro Biología Molecular 'Severo Ochoa' CSIC-UAM, Madrid, Spain
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17
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Castello MA, Jeppson JD, Soriano S. Moving beyond anti-amyloid therapy for the prevention and treatment of Alzheimer's disease. BMC Neurol 2014; 14:169. [PMID: 25179671 PMCID: PMC4236650 DOI: 10.1186/s12883-014-0169-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 08/18/2014] [Indexed: 12/21/2022] Open
Abstract
Background High-profile Phase 3 clinical trials of bapineuzumab and solanezumab, antibodies targeted at amyloid-beta (Aβ) removal, have failed to meet their primary endpoints. Neither drug improves clinical outcomes in patients with late onset AD, joining a long list of unsuccessful attempts to treat AD with anti-amyloid therapies. Discussion These therapies are based on the assumption that Aβ accumulation is the primary pathogenic trigger of AD. Current evidence suggests that Aβ may actually accumulate as part of an adaptive response to long-term chronic brain stress stimuli that would make more suitable candidates for therapeutic intervention. Summary At this juncture it is no longer unreasonable to suggest that further iterations of anti-Aβ therapies should be halted. Clinicians and researchers should instead direct their attention toward greater understanding of the biological function of Aβ both in healthy and demented brains, as well as the involvement of long-term chronic exposure to stress in the etiology of AD.
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Affiliation(s)
| | | | - Salvador Soriano
- Department of Anatomy, Loma Linda University School of Medicine, Evans Hall B08, 24785 Stewart Street, Loma Linda 92354, CA, USA.
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18
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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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