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Bharadwaj S, Groza Y, Mierzwicka JM, Malý P. Current understanding on TREM-2 molecular biology and physiopathological functions. Int Immunopharmacol 2024; 134:112042. [PMID: 38703564 DOI: 10.1016/j.intimp.2024.112042] [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: 02/08/2024] [Revised: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 05/06/2024]
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM-2), a glycosylated receptor belonging to the immunoglobin superfamily and especially expressed in the myeloid cell lineage, is frequently explained as a reminiscent receptor for both adaptive and innate immunity regulation. TREM-2 is also acknowledged to influence NK cell differentiation via the PI3K and PLCγ signaling pathways, as well as the partial activation or direct inhibition of T cells. Additionally, TREM-2 overexpression is substantially linked to cell-specific functions, such as enhanced phagocytosis, reduced toll-like receptor (TLR)-mediated inflammatory cytokine production, increased transcription of anti-inflammatory cytokines, and reshaped T cell function. Whereas TREM-2-deficient cells exhibit diminished phagocytic function and enhanced proinflammatory cytokines production, proceeding to inflammatory injuries and an immunosuppressive environment for disease progression. Despite the growing literature supporting TREM-2+ cells in various diseases, such as neurodegenerative disorders and cancer, substantial facets of TREM-2-mediated signaling remain inadequately understood relevant to pathophysiology conditions. In this direction, herein, we have summarized the current knowledge on TREM-2 biology and cell-specific TREM-2 expression, particularly in the modulation of pivotal TREM-2-dependent functions under physiopathological conditions. Furthermore, molecular regulation and generic biological relevance of TREM-2 are also discussed, which might provide an alternative approach for preventing or reducing TREM-2-associated deformities. At last, we discussed the TREM-2 function in supporting an immunosuppressive cancer environment and as a potential drug target for cancer immunotherapy. Hence, summarized knowledge of TREM-2 might provide a window to overcome challenges in clinically effective therapies for TREM-2-induced diseases in humans.
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Affiliation(s)
- Shiv Bharadwaj
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic.
| | - Yaroslava Groza
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Joanna M Mierzwicka
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Petr Malý
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic.
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2
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Wijegunawardena G, Castillo E, Henrickson B, Davis R, Condello C, Wu H. Total Chemical Synthesis of Glycosylated TREM2 Ectodomain. ACS Chem Neurosci 2023; 14:2243-2251. [PMID: 37235776 PMCID: PMC10786670 DOI: 10.1021/acschemneuro.3c00257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Mutations in a microglia-associated gene TREM2 increase the risk of Alzheimer's disease. Currently, structural and functional studies of TREM2 mainly rely on recombinant TREM2 proteins expressed from mammalian cells. However, using this method, it is difficult to achieve site-specific labeling. Here, we present the total chemical synthesis of the 116 amino acid TREM2 ectodomain. Rigorous structural analysis ensured correct structural fold after refolding. Treating microglial cells with refolded synthetic TREM2 enhanced microglial phagocytosis, proliferation, and survival. We also prepared TREM2 constructs with defined glycosylation patterns and found that glycosylation at N79 is critical to the thermal stability of TREM2. This method will provide access to TREM2 constructs with site-specific labeling, such as fluorescent labeling, reactive chemical handles, and enrichment handles, to further advance our understanding of TREM2 in Alzheimer's disease.
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Affiliation(s)
- Gayani Wijegunawardena
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Erika Castillo
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94158, United States
| | - Brandy Henrickson
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Regan Davis
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Carlo Condello
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94158, United States
- Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, United States
| | - Haifan Wu
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
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3
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Xue T, Ji J, Sun Y, Huang X, Cai Z, Yang J, Guo W, Guo R, Cheng H, Sun X. Sphingosine-1-phosphate, a novel TREM2 ligand, promotes microglial phagocytosis to protect against ischemic brain injury. Acta Pharm Sin B 2022; 12:1885-1898. [PMID: 35847502 PMCID: PMC9279640 DOI: 10.1016/j.apsb.2021.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/06/2021] [Accepted: 09/14/2021] [Indexed: 12/26/2022] Open
Affiliation(s)
- Tengfei Xue
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Juan Ji
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Yuqin Sun
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Xinxin Huang
- The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Zhenyu Cai
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Jin Yang
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Wei Guo
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Ruobing Guo
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Hong Cheng
- The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Xiulan Sun
- Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
- Nanjing University of Chinese Medicine, the Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210004, China
- Corresponding author.
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4
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Li XX, Zhang F. Targeting TREM2 for Parkinson's Disease: Where to Go? Front Immunol 2022; 12:795036. [PMID: 35003116 PMCID: PMC8740229 DOI: 10.3389/fimmu.2021.795036] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/13/2021] [Indexed: 12/16/2022] Open
Abstract
Parkinson’s disease (PD) is one of most common neurodegenerative disorders caused by a combination of environmental and genetic risk factors. Currently, numerous population genetic studies have shown that polymorphisms in myeloid cell-triggered receptor II (TREM2) are associated with a variety of neurodegenerative disorders. Recently, TREM2 has been verified to represent a promising candidate gene for PD susceptibility and progression. For example, the expression of TREM2 was apparently increased in the prefrontal cortex of PD patients. Moreover, the rare missense mutations in TREM2 (rs75932628, p.R47H) was confirmed to be a risk factor of PD. In addition, overexpression of TREM2 reduced dopaminergic neurodegeneration in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine mouse model of PD. Due to the complex pathogenesis of PD, there is still no effective drug treatment. Thus, TREM2 has received increasing widespread attention as a potential therapeutic target. This review focused on the variation of TREM2 in PD and roles of TREM2 in PD pathogenesis, such as excessive-immune inflammatory response, α-Synuclein aggregation and oxidative stress, to further provide evidence for new immune-related biomarkers and therapies for PD.
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Affiliation(s)
- Xiao-Xian Li
- Laboratory Animal Center and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Feng Zhang
- Laboratory Animal Center and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, China.,Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Guizhou Province, Zunyi Medical University, Zunyi, China
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5
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Byrne NJ, Lee AC, Kostas J, Reid JC, Partridge AT, So SS, Cowan JE, Abeywickrema P, Huang H, Zebisch M, Barker JJ, Soisson SM, Brooun A, Su HP. Development of a robust crystallization platform for immune receptor TREM2 using a crystallization chaperone strategy. Protein Expr Purif 2020; 179:105796. [PMID: 33221505 DOI: 10.1016/j.pep.2020.105796] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/15/2020] [Accepted: 11/13/2020] [Indexed: 11/18/2022]
Abstract
TREM2 has been identified by genomic analysis as a potential and novel target for the treatment of Alzheimer's disease. To enable structure-based screening of potential small molecule therapeutics, we sought to develop a robust crystallization platform for the TREM2 Ig-like domain. A systematic set of constructs containing the structural chaperone, maltose binding protein (MBP), fused to the Ig domain of TREM2, were evaluated in parallel expression and purification, followed by crystallization studies. Using protein crystallization and high-resolution diffraction as a readout, a MBP-TREM2 Ig fusion construct was identified that generates reproducible protein crystals diffracting at 2.0 Å, which makes it suitable for soaking of potential ligands. Importantly, analysis of crystal packing interfaces indicates that most of the surface of the TREM2 Ig domain is available for small molecule binding. A proof of concept co-crystallization study with a small library of fragments validated potential utility of this system for the discovery of new TREM2 therapeutics.
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Affiliation(s)
- Noel J Byrne
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA.
| | - Amy C Lee
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - James Kostas
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - John C Reid
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - Andrea T Partridge
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - Sung-Sau So
- Department of Computational and Structural Sciences, Merck & Co., Inc., Kenilworth, NJ, USA
| | - Joseph E Cowan
- Department of Discovery Sample Management, Merck & Co., Inc., Rahway, NJ, USA
| | - Pravien Abeywickrema
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | | | | | | | - Stephen M Soisson
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - Alexei Brooun
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
| | - Hua-Poo Su
- Department of Computational and Structural Sciences, Merck & Co., Inc., West Point, PA, USA
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6
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Toomey CE, Heywood W, Benson BC, Packham G, Mills K, Lashley T. Investigation of pathology, expression and proteomic profiles in human TREM2 variant postmortem brains with and without Alzheimer's disease. Brain Pathol 2020; 30:794-810. [PMID: 32267026 PMCID: PMC8018003 DOI: 10.1111/bpa.12842] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/11/2020] [Accepted: 03/26/2020] [Indexed: 12/17/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 TREM2 was identified as a risk factor for late onset Alzheimer’s disease (AD). Here we compared TREM2 cases with a variant (TREM2+) and cases without a TREM2 variant (TREM2−), considering pathological burden, inflammatory response and altered canonical pathways and biochemical functions between the cohorts. We hypothesised that TREM2+ cases would have a loss of function, indicating an altered inflammatory profile compared to TREM2− cases. Immunohistochemistry was performed using antibodies against Aβ, tau and microglia markers in TREM2+ cases, with and without AD, which were compared to sporadic TREM2− AD, familial AD and neurologically normal control cases. Aβ and tau load were measured along with the composition of Aβ plaques, in addition to microglial load and circularity. Expression and proteomic profiles were determined from the frontal cortex of selected cases. TREM2+ control cases had no Aβ or tau deposition. No differences in the amount of Aβ or tau, or the composition of Aβ plaques were observed between TREM2+ and TREM2− SAD cases. There were no differences in microglial load observed between disease groups. However, the TREM2+ SAD cases showed more amoeboid microglia than the TREM2− SAD cases, although no differences in the spatial relationship of microglia and Aβ plaques were identified. Visualisation of the canonical pathways and biological functions showed differences between the disease groups and the normal controls, clearly showing a number of pathways upregulated in TREM2+ SAD, TREM2− SAD and FAD groups whilst, the TREM2+ controls cases showed a downregulation of the majority of the represented pathways. These findings suggest that the TREM2+ control group, although carrying the TREM2+ variant, have no pathological hallmarks of AD, have altered microglial and expression profiles compared to the TREM2+ SAD cases. This indicates that other unknown factors may initiate the onset of AD, with TREM2 influencing the microglial involvement in disease pathogenesis.
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Affiliation(s)
- Christina E Toomey
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Wendy Heywood
- Centre for Translational Omics, Great Ormond Street Institute of Child Health, UCL, London, UK
| | - Bridget C Benson
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Georgia Packham
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Kevin Mills
- Centre for Translational Omics, Great Ormond Street Institute of Child Health, UCL, London, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative diseases, UCL Queen Square Institute of Neurology, London, UK
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7
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Dean HB, Roberson ED, Song Y. Neurodegenerative Disease-Associated Variants in TREM2 Destabilize the Apical Ligand-Binding Region of the Immunoglobulin Domain. Front Neurol 2019; 10:1252. [PMID: 32021611 PMCID: PMC6985895 DOI: 10.3389/fneur.2019.01252] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/11/2019] [Indexed: 01/22/2023] Open
Abstract
Single nucleotide variations in Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) have been linked to both late-onset Alzheimer's disease and behavioral variant frontotemporal dementia (FTD), the latter presenting either in isolation or with cystic bone lesions in a condition called Nasu-Hakola disease. Models of the extracellular domain of TREM2 show that Nasu-Hakola disease-associated mutations are grossly inactivating by truncation, frameshift, or unfolding, that Alzheimer's disease (AD)-associated variants localize to a putative ligand-interacting region (PLIR) on the extracellular surface, and that FTD-associated variants are found in the hydrophobic core. However, while these disease-associated residues are predicted to play some role in disrupting ligand binding to the extracellular domain of TREM2, how they ultimately lead to disease remains unknown. Here, we used in silico molecular modeling to investigate all-atom models of TREM2 and characterize the effects on conformation and dynamical motion of AD-associated R47H and R62H as well as FTD-associated T96K, D86V, and T66M variants compared to the benign N68K variant and the common variant. Our model, which is based on a published 2.2 Å resolution crystal structure of the TREM2 extracellular domain, finds that both AD- and FTD-associated variants cause localized instability in three loops adjacent to the PLIR that correspond to the complementarity-determining regions (CDRs) of antibodies. This instability ultimately disrupts tethering between these CDRs and the core of the immunoglobulin domain, exposing a group of otherwise-buried, negatively charged residues. This instability and exposure of negatively charged residues is most severe following introduction of the T66M variant that has been described as causing FTD even in the heterozygous state and is less severe following introduction of variants that are less strongly tied to FTD or of those associated with AD. Thus, our results provide further evidence that the proposed loss-of-function caused by neurodegenerative disease-associated variants may be driven by altered conformational stability of the ligand-interacting CDR and, ultimately, loss of affinity or specificity for TREM2 ligands.
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Affiliation(s)
- Hunter B Dean
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.,Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, United States.,Alzheimer's Disease Center, University of Alabama at Birmingham, Birmingham, AL, United States.,Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Erik D Roberson
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.,Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, United States.,Alzheimer's Disease Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yuhua Song
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States
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8
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Benefits and Challenges of Rare Genetic Variation in Alzheimer’s Disease. CURRENT GENETIC MEDICINE REPORTS 2019. [DOI: 10.1007/s40142-019-0161-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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9
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Sudom A, Talreja S, Danao J, Bragg E, Kegel R, Min X, Richardson J, Zhang Z, Sharkov N, Marcora E, Thibault S, Bradley J, Wood S, Lim AC, Chen H, Wang S, Foltz IN, Sambashivan S, Wang Z. Molecular basis for the loss-of-function effects of the Alzheimer's disease-associated R47H variant of the immune receptor TREM2. J Biol Chem 2018; 293:12634-12646. [PMID: 29794134 DOI: 10.1074/jbc.ra118.002352] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/08/2018] [Indexed: 12/22/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is an immune receptor expressed on the surface of microglia, macrophages, dendritic cells, and osteoclasts. The R47H TREM2 variant is a significant risk factor for late-onset Alzheimer's disease (AD), and the molecular basis of R47H TREM2 loss of function is an emerging area of TREM2 biology. Here, we report three high-resolution structures of the extracellular ligand-binding domains (ECDs) of R47H TREM2, apo-WT, and phosphatidylserine (PS)-bound WT TREM2 at 1.8, 2.2, and 2.2 Å, respectively. The structures reveal that Arg47 plays a critical role in maintaining the structural features of the complementarity-determining region 2 (CDR2) loop and the putative positive ligand-interacting surface (PLIS), stabilizing conformations capable of ligand interaction. This is exemplified in the PS-bound structure, in which the CDR2 loop and PLIS drive critical interactions with PS via surfaces that are disrupted in the variant. Together with in vitro and in vivo characterization, our structural findings elucidate the molecular mechanism underlying loss of ligand binding, putative oligomerization, and functional activity of R47H TREM2. They also help unravel how decreased in vitro and in vivo stability of TREM2 contribute to loss of function in disease.
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Affiliation(s)
- Athena Sudom
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080,
| | - Santosh Talreja
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Jean Danao
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Eric Bragg
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Rob Kegel
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Xiaoshan Min
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Jason Richardson
- Amgen Discovery Research, Amgen Inc., Thousand Oaks, California 91320, and
| | - Zhongqi Zhang
- Amgen Discovery Research, Amgen Inc., Thousand Oaks, California 91320, and
| | - Nikolai Sharkov
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Edoardo Marcora
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Steve Thibault
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Jodi Bradley
- Amgen Discovery Research, Amgen Inc., Thousand Oaks, California 91320, and
| | - Steve Wood
- Amgen Discovery Research, Amgen Inc., Thousand Oaks, California 91320, and
| | - Ai-Ching Lim
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Hang Chen
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Songli Wang
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080
| | - Ian N Foltz
- Amgen Discovery Research, Amgen Inc., Burnaby, British Columbia V5A 1V7, Canada
| | - Shilpa Sambashivan
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080,
| | - Zhulun Wang
- From Amgen Discovery Research, Amgen Inc., San Francisco, California 94080,
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10
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Jay TR, von Saucken VE, Landreth GE. TREM2 in Neurodegenerative Diseases. Mol Neurodegener 2017; 12:56. [PMID: 28768545 PMCID: PMC5541421 DOI: 10.1186/s13024-017-0197-5] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
TREM2 variants have been identified as risk factors for Alzheimer's disease (AD) and other neurodegenerative diseases (NDDs). Because TREM2 encodes a receptor exclusively expressed on immune cells, identification of these variants conclusively demonstrates that the immune response can play an active role in the pathogenesis of NDDs. These TREM2 variants also confer the highest risk for developing Alzheimer's disease of any risk factor identified in nearly two decades, suggesting that understanding more about TREM2 function could provide key insights into NDD pathology and provide avenues for novel immune-related NDD biomarkers and therapeutics. The expression, signaling and function of TREM2 in NDDs have been extensively investigated in an effort to understand the role of immune function in disease pathogenesis and progression. We provide a comprehensive review of our current understanding of TREM2 biology, including new insights into the regulation of TREM2 expression, and TREM2 signaling and function across NDDs. While many open questions remain, the current body of literature provides clarity on several issues. While it is still often cited that TREM2 expression is decreased by pro-inflammatory stimuli, it is now clear that this is true in vitro, but inflammatory stimuli in vivo almost universally increase TREM2 expression. Likewise, while TREM2 function is classically described as promoting an anti-inflammatory phenotype, more than half of published studies demonstrate a pro-inflammatory role for TREM2, suggesting that its role in inflammation is much more complex. Finally, these components of TREM2 biology are applied to a discussion of how TREM2 impacts NDD pathologies and the latest assessment of how these findings might be applied to immune-directed clinical biomarkers and therapeutics.
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Affiliation(s)
- Taylor R. Jay
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
| | - Victoria E. von Saucken
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
| | - Gary E. Landreth
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
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11
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Kober DL, Alexander-Brett JM, Karch CM, Cruchaga C, Colonna M, Holtzman MJ, Brett TJ. Neurodegenerative disease mutations in TREM2 reveal a functional surface and distinct loss-of-function mechanisms. eLife 2016; 5:e20391. [PMID: 27995897 PMCID: PMC5173322 DOI: 10.7554/elife.20391] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/28/2016] [Indexed: 01/09/2023] Open
Abstract
Genetic variations in the myeloid immune receptor TREM2 are linked to several neurodegenerative diseases. To determine how TREM2 variants contribute to these diseases, we performed structural and functional studies of wild-type and variant proteins. Our 3.1 Å TREM2 crystal structure revealed that mutations found in Nasu-Hakola disease are buried whereas Alzheimer's disease risk variants are found on the surface, suggesting that these mutations have distinct effects on TREM2 function. Biophysical and cellular methods indicate that Nasu-Hakola mutations impact protein stability and decrease folded TREM2 surface expression, whereas Alzheimer's risk variants impact binding to a TREM2 ligand. Additionally, the Alzheimer's risk variants appear to epitope map a functional surface on TREM2 that is unique within the larger TREM family. These findings provide a guide to structural and functional differences among genetic variants of TREM2, indicating that therapies targeting the TREM2 pathway should be tailored to these genetic and functional differences with patient-specific medicine approaches for neurodegenerative disorders.
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Affiliation(s)
- Daniel L Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, St. Louis, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
| | - Jennifer M Alexander-Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
| | - Celeste M Karch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, United States
| | - Carlos Cruchaga
- Department of Psychiatry, Washington University School of Medicine, St. Louis, United States
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, United States
| | - Michael J Holtzman
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Thomas J Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
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12
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Kober DL, Yurtsever Z, Brett TJ. Efficient Mammalian Cell Expression and Single-step Purification of Extracellular Glycoproteins for Crystallization. J Vis Exp 2015:e53445. [PMID: 26780656 DOI: 10.3791/53445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Production of secreted mammalian proteins for structural and biophysical studies can be challenging, time intensive, and costly. Here described is a time and cost efficient protocol for secreted protein expression in mammalian cells and one step purification using nickel affinity chromatography. The system is based on large scale transient transfection of mammalian cells in suspension, which greatly decreases the time to produce protein, as it eliminates steps, such as developing expression viruses or generating stable expressing cell lines. This protocol utilizes cheap transfection agents, which can be easily made by simple chemical modification, or moderately priced transfection agents, which increase yield through increased transfection efficiency and decreased cytotoxicity. Careful monitoring and maintaining of media glucose levels increases protein yield. Controlling the maturation of native glycans at the expression step increases the final yield of properly folded and functional mammalian proteins, which are ideal properties to pursue X-ray crystallography. In some cases, single step purification produces protein of sufficient purity for crystallization, which is demonstrated here as an example case.
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Affiliation(s)
- Daniel L Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine; Department of Internal Medicine, Washington University School of Medicine; Drug Discovery Program in Pulmonary and Critical Care Medicine, Washington University School of Medicine
| | - Zeynep Yurtsever
- Department of Internal Medicine, Washington University School of Medicine; Drug Discovery Program in Pulmonary and Critical Care Medicine, Washington University School of Medicine; Biochemistry Program, Washington University School of Medicine; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine
| | - Thomas J Brett
- Department of Internal Medicine, Washington University School of Medicine; Drug Discovery Program in Pulmonary and Critical Care Medicine, Washington University School of Medicine; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine; Department of Cell Biology and Physiology, Washington University School of Medicine;
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Wu K, Byers DE, Jin X, Agapov E, Alexander-Brett J, Patel AC, Cella M, Gilfilan S, Colonna M, Kober DL, Brett TJ, Holtzman MJ. TREM-2 promotes macrophage survival and lung disease after respiratory viral infection. ACTA ACUST UNITED AC 2015; 212:681-97. [PMID: 25897174 PMCID: PMC4419356 DOI: 10.1084/jem.20141732] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 03/20/2015] [Indexed: 01/04/2023]
Abstract
Wu et al. use a mouse model to show that active respiratory viral infection triggers TREM-2 expression on the macrophage cell surface and thereby prevents macrophage apoptosis during the acute illness. In addition, long after viral clearance, IL-13 and DAP12 promote TREM-2 cleavage to its soluble form that unexpectedly also enhances macrophage survival and promotes chronic inflammatory disease. Viral infections and type 2 immune responses are thought to be critical for the development of chronic respiratory disease, but the link between these events needs to be better defined. Here, we study a mouse model in which infection with a mouse parainfluenza virus known as Sendai virus (SeV) leads to long-term activation of innate immune cells that drive IL-13–dependent lung disease. We find that chronic postviral disease (signified by formation of excess airway mucus and accumulation of M2-differentiating lung macrophages) requires macrophage expression of triggering receptor expressed on myeloid cells-2 (TREM-2). Analysis of mechanism shows that viral replication increases lung macrophage levels of intracellular and cell surface TREM-2, and this action prevents macrophage apoptosis that would otherwise occur during the acute illness (5–12 d after inoculation). However, the largest increases in TREM-2 levels are found as the soluble form (sTREM-2) long after clearance of infection (49 d after inoculation). At this time, IL-13 and the adapter protein DAP12 promote TREM-2 cleavage to sTREM-2 that is unexpectedly active in preventing macrophage apoptosis. The results thereby define an unprecedented mechanism for a feed-forward expansion of lung macrophages (with IL-13 production and consequent M2 differentiation) that further explains how acute infection leads to chronic inflammatory disease.
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Affiliation(s)
- Kangyun Wu
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Derek E Byers
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Xiaohua Jin
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Eugene Agapov
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Jennifer Alexander-Brett
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Anand C Patel
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110 Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Marina Cella
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Susan Gilfilan
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Marco Colonna
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Daniel L Kober
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Tom J Brett
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110 Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110 Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael J Holtzman
- Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110 Pulmonary and Critical Care Medicine, Department of Medicine, Department of Pediatrics, Department of Pathology and Immunology, Department of Biochemistry and Biophysics, and Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110
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