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Filipello F, You SF, Mirfakhar FS, Mahali S, Bollman B, Acquarone M, Korvatska O, Marsh JA, Sivaraman A, Martinez R, Cantoni C, De Feo L, Ghezzi L, Minaya MA, Renganathan A, Cashikar AG, Satoh JI, Beatty W, Iyer AK, Cella M, Raskind WH, Piccio L, Karch CM. Defects in lysosomal function and lipid metabolism in human microglia harboring a TREM2 loss of function mutation. Acta Neuropathol 2023; 145:749-772. [PMID: 37115208 PMCID: PMC10175346 DOI: 10.1007/s00401-023-02568-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/29/2023]
Abstract
TREM2 is an innate immune receptor expressed by microglia in the adult brain. Genetic variation in the TREM2 gene has been implicated in risk for Alzheimer's disease and frontotemporal dementia, while homozygous TREM2 mutations cause a rare leukodystrophy, Nasu-Hakola disease (NHD). Despite extensive investigation, the role of TREM2 in NHD pathogenesis remains poorly understood. Here, we investigate the mechanisms by which a homozygous stop-gain TREM2 mutation (p.Q33X) contributes to NHD. Induced pluripotent stem cell (iPSC)-derived microglia (iMGLs) were generated from two NHD families: three homozygous TREM2 p.Q33X mutation carriers (termed NHD), two heterozygous mutation carriers, one related non-carrier, and two unrelated non-carriers. Transcriptomic and biochemical analyses revealed that iMGLs from NHD patients exhibited lysosomal dysfunction, downregulation of cholesterol genes, and reduced lipid droplets compared to controls. Also, NHD iMGLs displayed defective activation and HLA antigen presentation. This defective activation and lipid droplet content were restored by enhancing lysosomal biogenesis through mTOR-dependent and independent pathways. Alteration in lysosomal gene expression, such as decreased expression of genes implicated in lysosomal acidification (ATP6AP2) and chaperone mediated autophagy (LAMP2), together with reduction in lipid droplets were also observed in post-mortem brain tissues from NHD patients, thus closely recapitulating in vivo the phenotype observed in iMGLs in vitro. Our study provides the first cellular and molecular evidence that the TREM2 p.Q33X mutation in microglia leads to defects in lysosomal function and that compounds targeting lysosomal biogenesis restore a number of NHD microglial defects. A better understanding of how microglial lipid metabolism and lysosomal machinery are altered in NHD and how these defects impact microglia activation may provide new insights into mechanisms underlying NHD and other neurodegenerative diseases.
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Affiliation(s)
- Fabia Filipello
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Shih-Feng You
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | | | - Sidhartha Mahali
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Bryan Bollman
- Department of Neurology, Washington University in St Louis, St Louis, MO, USA
| | - Mariana Acquarone
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Olena Korvatska
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Jacob A Marsh
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Anirudh Sivaraman
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Rita Martinez
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Claudia Cantoni
- Department of Neurology, Washington University in St Louis, St Louis, MO, USA
| | - Luca De Feo
- Department of Neurology, Washington University in St Louis, St Louis, MO, USA
| | - Laura Ghezzi
- Department of Neurology, Washington University in St Louis, St Louis, MO, USA
| | - Miguel A Minaya
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Arun Renganathan
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Anil G Cashikar
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Jun-Ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Tokyo, Japan
| | - Wandy Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Abhirami K Iyer
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA
| | - Marina Cella
- Department Of Pathology and Immunology, Washington University in St Louis, St Louis, MO, USA
| | - Wendy H Raskind
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, USA
| | - Laura Piccio
- Department of Neurology, Washington University in St Louis, St Louis, MO, USA.
- Charles Perkins Centre and Brain and Mind Centre, School of Medical Sciences (Neuroscience), University of Sydney, Sydney, NSW, Australia.
- School of Medical Sciences, Brain and Mind Centre, University of Sydney, 94 Mallett St, Camperdown, Sydney, NSW, 2050, Australia.
| | - Celeste M Karch
- Department of Psychiatry, Washington University in St Louis, St Louis, MO, USA.
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Perdigão C, Barata MA, Araújo MN, Mirfakhar FS, Castanheira J, Guimas Almeida C. Intracellular Trafficking Mechanisms of Synaptic Dysfunction in Alzheimer's Disease. Front Cell Neurosci 2020; 14:72. [PMID: 32362813 PMCID: PMC7180223 DOI: 10.3389/fncel.2020.00072] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 03/12/2020] [Indexed: 12/15/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disease characterized by progressive memory loss. Although AD neuropathological hallmarks are extracellular amyloid plaques and intracellular tau tangles, the best correlate of disease progression is synapse loss. What causes synapse loss has been the focus of several researchers in the AD field. Synapses become dysfunctional before plaques and tangles form. Studies based on early-onset familial AD (eFAD) models have supported that synaptic transmission is depressed by β-amyloid (Aβ) triggered mechanisms. Since eFAD is rare, affecting only 1% of patients, research has shifted to the study of the most common late-onset AD (LOAD). Intracellular trafficking has emerged as one of the pathways of LOAD genes. Few studies have assessed the impact of trafficking LOAD genes on synapse dysfunction. Since endocytic traffic is essential for synaptic function, we reviewed Aβ-dependent and independent mechanisms of the earliest synaptic dysfunction in AD. We have focused on the role of intraneuronal and secreted Aβ oligomers, highlighting the dysfunction of endocytic trafficking as an Aβ-dependent mechanism of synapse dysfunction in AD. Here, we reviewed the LOAD trafficking genes APOE4, ABCA7, BIN1, CD2AP, PICALM, EPH1A, and SORL1, for which there is a synaptic link. We conclude that in eFAD and LOAD, the earliest synaptic dysfunctions are characterized by disruptions of the presynaptic vesicle exo- and endocytosis and of postsynaptic glutamate receptor endocytosis. While in eFAD synapse dysfunction seems to be triggered by Aβ, in LOAD, there might be a direct synaptic disruption by LOAD trafficking genes. To identify promising therapeutic targets and biomarkers of the earliest synaptic dysfunction in AD, it will be necessary to join efforts in further dissecting the mechanisms used by Aβ and by LOAD genes to disrupt synapses.
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Affiliation(s)
- Catarina Perdigão
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Mariana A Barata
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Margarida N Araújo
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Farzaneh S Mirfakhar
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Jorge Castanheira
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Cláudia Guimas Almeida
- Laboratory Neuronal Trafficking in Aging, CEDOC Chronic Diseases Research Center, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
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