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Fu WY, Ip NY. The role of genetic risk factors of Alzheimer's disease in synaptic dysfunction. Semin Cell Dev Biol 2023; 139:3-12. [PMID: 35918217 DOI: 10.1016/j.semcdb.2022.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by the progressive deterioration of cognitive functions. Due to the extended global life expectancy, the prevalence of AD is increasing among aging populations worldwide. While AD is a multifactorial disease, synaptic dysfunction is one of the major neuropathological changes that occur early in AD, before clinical symptoms appear, and is associated with the progression of cognitive deterioration. However, the underlying pathological mechanisms leading to this synaptic dysfunction remains unclear. Recent large-scale genomic analyses have identified more than 40 genetic risk factors that are associated with AD. In this review, we discuss the functional roles of these genes in synaptogenesis and synaptic functions under physiological conditions, and how their functions are dysregulated in AD. This will provide insights into the contributions of these encoded proteins to synaptic dysfunction during AD pathogenesis.
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Affiliation(s)
- Wing-Yu Fu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China
| | - Nancy Y Ip
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China.
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Kisler K, Sagare AP, Lazic D, Bazzi S, Lawson E, Hsu CJ, Wang Y, Ramanathan A, Nelson AR, Zhao Z, Zlokovic BV. Anti-malaria drug artesunate prevents development of amyloid-β pathology in mice by upregulating PICALM at the blood-brain barrier. Mol Neurodegener 2023; 18:7. [PMID: 36707892 PMCID: PMC9883925 DOI: 10.1186/s13024-023-00597-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/13/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND PICALM is one of the most significant susceptibility factors for Alzheimer's disease (AD). In humans and mice, PICALM is highly expressed in brain endothelium. PICALM endothelial levels are reduced in AD brains. PICALM controls several steps in Aβ transcytosis across the blood-brain barrier (BBB). Its loss from brain endothelium in mice diminishes Aβ clearance at the BBB, which worsens Aβ pathology, but is reversible by endothelial PICALM re-expression. Thus, increasing PICALM at the BBB holds potential to slow down development of Aβ pathology. METHODS To identify a drug that could increase PICALM expression, we screened a library of 2007 FDA-approved drugs in HEK293t cells expressing luciferase driven by a human PICALM promoter, followed by a secondary mRNA screen in human Eahy926 endothelial cell line. In vivo studies with the lead hit were carried out in Picalm-deficient (Picalm+/-) mice, Picalm+/-; 5XFAD mice and Picalmlox/lox; Cdh5-Cre; 5XFAD mice with endothelial-specific Picalm knockout. We studied PICALM expression at the BBB, Aβ pathology and clearance from brain to blood, cerebral blood flow (CBF) responses, BBB integrity and behavior. RESULTS Our screen identified anti-malaria drug artesunate as the lead hit. Artesunate elevated PICALM mRNA and protein levels in Eahy926 endothelial cells and in vivo in brain capillaries of Picalm+/- mice by 2-3-fold. Artesunate treatment (32 mg/kg/day for 2 months) of 3-month old Picalm+/-; 5XFAD mice compared to vehicle increased brain capillary PICALM levels by 2-fold, and reduced Aβ42 and Aβ40 levels and Aβ and thioflavin S-load in the cortex and hippocampus, and vascular Aβ load by 34-51%. Artesunate also increased circulating Aβ42 and Aβ40 levels by 2-fold confirming accelerated Aβ clearance from brain to blood. Consistent with reduced Aβ pathology, treatment of Picalm+/-; 5XFAD mice with artesunate improved CBF responses, BBB integrity and behavior on novel object location and recognition, burrowing and nesting. Endothelial-specific knockout of PICALM abolished all beneficial effects of artesunate in 5XFAD mice indicating that endothelial PICALM is required for its therapeutic effects. CONCLUSIONS Artesunate increases PICALM levels and Aβ clearance at the BBB which prevents development of Aβ pathology and functional deficits in mice and holds potential for translation to human AD.
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Affiliation(s)
- Kassandra Kisler
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Abhay P. Sagare
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Divna Lazic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Sam Bazzi
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Erica Lawson
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Ching-Ju Hsu
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Yaoming Wang
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Anita Ramanathan
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Amy R. Nelson
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Zhen Zhao
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
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PICALM rs3851179 Variants Modulate Left Postcentral Cortex Thickness, CSF Amyloid β42, and Phosphorylated Tau in the Elderly. Brain Sci 2022; 12:brainsci12121681. [PMID: 36552141 PMCID: PMC9776362 DOI: 10.3390/brainsci12121681] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/25/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
PICALM rs3851179, one of the genes most frequently linked to susceptibility of late-onset Alzheimer's disease (LOAD), plays a crucial role in regulating amyloid precursor protein, and amyloid β (Aβ) transcytosis. To explore the effects of PICALM and AD continuum stage on cortex thickness, CSF Aβ, and tau, 188 cognitively normal controls, 261 MCI patients, and 140 early LOAD patients were recruited, and each group was divided into rs3851179 A-carriers and GG-carriers. A full factorial ANCOVA was used to analyze the main effects and interactive effects of AD continuum stage, and PICALM. The interactive effects of AD continuum stage and PICALM on cortex thickness and CSF biomarkers were not significant. The main effect of PICALM was significant on the left postcentral cortex thickness, and the cortex thickness of A-carriers was less than that of GG-carriers. The rs3851179 A-carriers displayed higher Aβ42 levels and Aβ42/40 ratios, and lower P/T-tau ratios, compared with GG-carriers. A higher MMSE score was found in A-carriers among the LOAD patients. In conclusion, the main effects of PICALM were independent of AD continuum stage, and PICLAM rs3851179 genotypes may modulate left postcentral cortex thickness, Aβ42 level, and P/T-tau ratio. The rs3851179 A-allele may protect the cognitive function of LOAD patients.
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CALM supports clathrin-coated vesicle completion upon membrane tension increase. Proc Natl Acad Sci U S A 2021; 118:2010438118. [PMID: 34155137 DOI: 10.1073/pnas.2010438118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The most represented components of clathrin-coated vesicles (CCVs) are clathrin triskelia and the adaptors clathrin assembly lymphoid myeloid leukemia protein (CALM) and the heterotetrameric complex AP2. Investigation of the dynamics of AP180-amino-terminal-homology (ANTH) recruitment during CCV formation has been hampered by CALM toxicity upon overexpression. We used knock-in gene editing to express a C-terminal-attached fluorescent version of CALM, while preserving its endogenous expression levels, and cutting-edge live-cell microscopy approaches to study CALM recruitment at forming CCVs. Our results demonstrate that CALM promotes vesicle completion upon membrane tension increase as a function of the amount of this adaptor present. Since the expression of adaptors, including CALM, differs among cells, our data support a model in which the efficiency of clathrin-mediated endocytosis is tissue specific and explain why CALM is essential during embryogenesis and red blood cell development.
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Gockley J, Montgomery KS, Poehlman WL, Wiley JC, Liu Y, Gerasimov E, Greenwood AK, Sieberts SK, Wingo AP, Wingo TS, Mangravite LM, Logsdon BA. Multi-tissue neocortical transcriptome-wide association study implicates 8 genes across 6 genomic loci in Alzheimer's disease. Genome Med 2021; 13:76. [PMID: 33947463 PMCID: PMC8094491 DOI: 10.1186/s13073-021-00890-2] [Citation(s) in RCA: 16] [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: 06/30/2020] [Accepted: 04/17/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is an incurable neurodegenerative disease currently affecting 1.75% of the US population, with projected growth to 3.46% by 2050. Identifying common genetic variants driving differences in transcript expression that confer AD risk is necessary to elucidate AD mechanism and develop therapeutic interventions. We modify the FUSION transcriptome-wide association study (TWAS) pipeline to ingest gene expression values from multiple neocortical regions. METHODS A combined dataset of 2003 genotypes clustered to 1000 Genomes individuals from Utah with Northern and Western European ancestry (CEU) was used to construct a training set of 790 genotypes paired to 888 RNASeq profiles from temporal cortex (TCX = 248), prefrontal cortex (FP = 50), inferior frontal gyrus (IFG = 41), superior temporal gyrus (STG = 34), parahippocampal cortex (PHG = 34), and dorsolateral prefrontal cortex (DLPFC = 461). Following within-tissue normalization and covariate adjustment, predictive weights to impute expression components based on a gene's surrounding cis-variants were trained. The FUSION pipeline was modified to support input of pre-scaled expression values and support cross validation with a repeated measure design arising from the presence of multiple transcriptome samples from the same individual across different tissues. RESULTS Cis-variant architecture alone was informative to train weights and impute expression for 6780 (49.67%) autosomal genes, the majority of which significantly correlated with gene expression; FDR < 5%: N = 6775 (99.92%), Bonferroni: N = 6716 (99.06%). Validation of weights in 515 matched genotype to RNASeq profiles from the CommonMind Consortium (CMC) was (72.14%) in DLPFC profiles. Association of imputed expression components from all 2003 genotype profiles yielded 8 genes significantly associated with AD (FDR < 0.05): APOC1, EED, CD2AP, CEACAM19, CLPTM1, MTCH2, TREM2, and KNOP1. CONCLUSIONS We provide evidence of cis-genetic variation conferring AD risk through 8 genes across six distinct genomic loci. Moreover, we provide expression weights for 6780 genes as a valuable resource to the community, which can be abstracted across the neocortex and a wide range of neuronal phenotypes.
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Affiliation(s)
| | | | | | | | - Yue Liu
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Ekaterina Gerasimov
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | | | | | - Aliza P Wingo
- Division of Mental Health, Atlanta VA Medical Center, Decatur, GA, USA
- Department of Psychiatry, Emory University School of Medicine, Atlanta, GA, USA
| | - Thomas S Wingo
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | | | - Benjamin A Logsdon
- Cajal Neuroscience, 1616 Eastlake Avenue East, Suite 208, Seattle, WA, 98102, USA.
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Seto M, Weiner RL, Dumitrescu L, Hohman TJ. Protective genes and pathways in Alzheimer's disease: moving towards precision interventions. Mol Neurodegener 2021; 16:29. [PMID: 33926499 PMCID: PMC8086309 DOI: 10.1186/s13024-021-00452-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/20/2021] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive, neurodegenerative disorder that is characterized by neurodegeneration, cognitive impairment, and an eventual inability to perform daily tasks. The etiology of Alzheimer's is complex, with numerous environmental and genetic factors contributing to the disease. Late-onset AD is highly heritable (60 to 80%), and over 40 risk loci for AD have been identified via large genome-wide association studies, most of which are common variants with small effect sizes. Although these discoveries have provided novel insight on biological contributors to AD, disease-modifying treatments remain elusive. Recently, the concepts of resistance to pathology and resilience against the downstream consequences of pathology have been of particular interest in the Alzheimer's field as studies continue to identify individuals who evade the pathology of the disease even into late life and individuals who have all of the neuropathological features of AD but evade downstream neurodegeneration and cognitive impairment. It has been hypothesized that a shift in focus from Alzheimer's risk to resilience presents an opportunity to uncover novel biological mechanisms of AD and to identify promising therapeutic targets for the disease. This review will highlight a selection of genes and variants that have been reported to confer protection from AD within the literature and will also discuss evidence for the biological underpinnings behind their protective effect with a focus on genes involved in lipid metabolism, cellular trafficking, endosomal and lysosomal function, synaptic function, and inflammation. Finally, we offer some recommendations in areas where the field can rapidly advance towards precision interventions that leverage the ideas of protection and resilience for the development of novel therapeutic strategies.
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Affiliation(s)
- Mabel Seto
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, 1207 17th Ave S, Nashville, TN 37212 USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN USA
| | - Rebecca L. Weiner
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, 1207 17th Ave S, Nashville, TN 37212 USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN USA
| | - Logan Dumitrescu
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, 1207 17th Ave S, Nashville, TN 37212 USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Timothy J. Hohman
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, 1207 17th Ave S, Nashville, TN 37212 USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN USA
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Affiliation(s)
- Keshen Li
- Department of Neurology and Stroke Center, the First Affiliated Hospital Clinical Neuroscience Institute of Jinan University Jinan University, Guangzhou, China
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Yu Y, Niccoli T, Ren Z, Woodling NS, Aleyakpo B, Szabadkai G, Partridge L. PICALM rescues glutamatergic neurotransmission, behavioural function and survival in a Drosophila model of Aβ42 toxicity. Hum Mol Genet 2020; 29:2420-2434. [PMID: 32592479 PMCID: PMC7424762 DOI: 10.1093/hmg/ddaa125] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia and the most prevalent neurodegenerative disease. Genome-wide association studies have linked PICALM to AD risk. PICALM has been implicated in Aβ42 production and turnover, but whether it plays a direct role in modulating Aβ42 toxicity remains unclear. We found that increased expression of the Drosophila PICALM orthologue lap could rescue Aβ42 toxicity in an adult-onset model of AD, without affecting Aβ42 level. Imbalances in the glutamatergic system, leading to excessive, toxic stimulation, have been associated with AD. We found that Aβ42 caused the accumulation of presynaptic vesicular glutamate transporter (VGlut) and increased spontaneous glutamate release. Increased lap expression reversed these phenotypes back to control levels, suggesting that lap may modulate glutamatergic transmission. We also found that lap modulated the localization of amphiphysin (Amph), the homologue of another AD risk factor BIN1, and that Amph itself modulated postsynaptic glutamate receptor (GluRII) localization. We propose a model where PICALM modulates glutamatergic transmission, together with BIN1, to ameliorate synaptic dysfunction and disease progression.
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Affiliation(s)
- Yifan Yu
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London WC1E 6BT, UK
| | - Teresa Niccoli
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Ziyu Ren
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK
| | - Nathaniel S Woodling
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London WC1E 6BT, UK
| | - Benjamin Aleyakpo
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London WC1E 6BT, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK
- The Francis Crick Institute, London NW1 1AT, UK
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Linda Partridge
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London WC1E 6BT, UK
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
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