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TREM2 — a key player in microglial biology and Alzheimer disease

Abstract

Alzheimer disease (AD) is a debilitating dementia believed to result from the deposition of extracellular amyloid-β (Aβ)-containing plaques followed by the formation of neurofibrillary tangles. Familial AD typically results from mutations in the genes encoding amyloid precursor protein (APP), presenilin 1 or presenilin 2. Variations in triggering receptor expressed on myeloid cells 2 (TREM2), one of several genes for which expression is restricted to microglia in the brain, have now been shown to increase the risk of developing late-onset AD. Microglia have been shown to respond to Aβ accumulation and neurodegenerative lesions, progressively acquiring a unique transcriptional and functional signature and evolving into disease-associated microglia (DAM). DAM attenuate the progression of neurodegeneration in certain mouse models, but inappropriate DAM activation accelerates neurodegenerative disease in other models. TREM2 is essential for maintaining microglial metabolic fitness during stress events, enabling microglial progression to a fully mature DAM profile and ultimately sustaining the microglial response to Aβ-plaque-induced pathology. Here, we review the current data detailing the role of TREM2 in microglial biology and AD.

Key points

  • During the development of Alzheimer disease (AD)-associated pathology, homeostatic microglia progressively acquire a unique transcriptional and functional signature and evolve into disease-associated microglia (DAM).

  • DAM can contain amyloid-β plaques and protect surrounding neuronal tissue.

  • Rare loss-of-function variants in the gene encoding triggering receptor expressed on myeloid cells 2 (TREM2) increase the risk of developing AD in humans.

  • Microglia require TREM2 for full acquisition of a DAM profile.

  • TREM2 is needed to enhance mechanistic target of rapamycin (mTOR) signalling and to boost the metabolic capacity of microglia.

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Fig. 1: Domain structures of TREM2 and associated signalling adaptor molecules DAP12 and DAP10.
Fig. 2: Generation of soluble TREM2 by sequential actions of ADAM17, ADAM10 and γ-secretase.
Fig. 3: Signalling pathways linking TREM2 activation and energetic cellular metabolism.
Fig. 4: The TREM2–mTOR axis potentiates and sustains the microglial response to amyloid-β plaques.

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References

  1. Alzheimer’s Association. 2016 Alzheimer’s disease facts and figures. Alzheimers Dement. 12, 459–509 (2016).

    Google Scholar 

  2. Holtzman, D. M., Morris, J. C. & Goate, A. M. Alzheimer’s disease: the challenge of the second century. Sci. Transl Med. 3, 77sr71 (2011).

    Google Scholar 

  3. St George-Hyslop, P. H. et al. The genetic defect causing familial Alzheimer’s disease maps on chromosome 21. Science 235, 885–890 (1987).

    Google Scholar 

  4. Sherrington, R. et al. Cloning of a gene bearing missense mutations in early-onset familial Alzheimer’s disease. Nature 375, 754–760 (1995).

    CAS  PubMed  Google Scholar 

  5. Goate, A. et al. Segregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimer’s disease. Nature 349, 704–706 (1991).

    CAS  PubMed  Google Scholar 

  6. Levy, E. et al. Mutation of the Alzheimer’s disease amyloid gene in hereditary cerebral hemorrhage, Dutch type. Science 248, 1124–1126 (1990).

    CAS  PubMed  Google Scholar 

  7. Levy-Lahad, E. et al. Candidate gene for the chromosome 1 familial Alzheimer’s disease locus. Science 269, 973–977 (1995).

    CAS  PubMed  Google Scholar 

  8. Rogaev, E. I. et al. Familial Alzheimer’s disease in kindreds with missense mutations in a gene on chromosome 1 related to the Alzheimer’s disease type 3 gene. Nature 376, 775–778 (1995).

    CAS  PubMed  Google Scholar 

  9. Jonsson, T. et al. Variant of TREM2 associated with the risk of Alzheimer’s disease. N. Engl. J. Med. 368, 107–116 (2013).

    CAS  PubMed  Google Scholar 

  10. Guerreiro, R. et al. TREM2 variants in Alzheimer’s disease. N. Engl. J. Med. 368, 117–127 (2013).

    CAS  PubMed  Google Scholar 

  11. Sims, R. et al. Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer’s disease. Nat. Genet. 49, 1373–1384 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  12. Hollingworth, P. et al. Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer’s disease. Nat. Genet. 43, 429–435 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  13. Corder, E. H. et al. Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer’s disease in late onset families. Science 261, 921–923 (1993).

    CAS  PubMed  Google Scholar 

  14. Strittmatter, W. J. et al. Apolipoprotein E: high-avidity binding to beta-amyloid and increased frequency of type 4 allele in late-onset familial Alzheimer disease. Proc. Natl Acad. Sci. USA 90, 1977–1981 (1993).

    CAS  PubMed  Google Scholar 

  15. Song, W. et al. Alzheimer’s disease-associated TREM2 variants exhibit either decreased or increased ligand-dependent activation. Alzheimers Dement. 13, 381–387 (2017).

    PubMed  Google Scholar 

  16. Benitez, B. A. et al. TREM2 is associated with the risk of Alzheimer’s disease in Spanish population. Neurobiol. Aging 34, 1711 (2013).

    PubMed  PubMed Central  Google Scholar 

  17. Ruiz, A. et al. Assessing the role of the TREM2 p. R47H variant as a risk factor for Alzheimer’s disease and frontotemporal dementia. Neurobiol. Aging 35, 444 (2014).

    PubMed  Google Scholar 

  18. Slattery, C. F. et al. R47H TREM2 variant increases risk of typical early-onset Alzheimer’s disease but not of prion or frontotemporal dementia. Alzheimers Dement. 10, 602–608 (2014).

    PubMed  Google Scholar 

  19. Karch, C. M., Cruchaga, C. & Goate, A. M. Alzheimer’s disease genetics: from the bench to the clinic. Neuron 83, 11–26 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  20. Bertram, L. et al. Genome-wide association analysis reveals putative Alzheimer’s disease susceptibility loci in addition to APOE. Am. J. Hum. Genet. 83, 623–632 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  21. Naj, A. C. et al. Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer’s disease. Nat. Genet. 43, 436–441 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  22. Harold, D. et al. Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer’s disease. Nat. Genet. 41, 1088–1093 (2009).

    CAS  PubMed  PubMed Central  Google Scholar 

  23. Lambert, J. C. et al. Genome-wide association study identifies variants at CLU and CR1 associated with Alzheimer’s disease. Nat. Genet. 41, 1094–1099 (2009).

    CAS  PubMed  Google Scholar 

  24. Seshadri, S. et al. Genome-wide analysis of genetic loci associated with Alzheimer disease. JAMA 303, 1832–1840 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  25. Lambert, J. C. et al. Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer’s disease. Nat. Genet. 45, 1452–1458 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  26. Miyashita, A. et al. SORL1 is genetically associated with late-onset Alzheimer’s disease in Japanese, Koreans and Caucasians. PLoS ONE 8, e58618 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. Nissl, F. in Histologische und histopathologische Arbeiten über die Grosshirnrinde Vol. 1 (eds. Nissl, F., Alzheimer, A.) 315–494 (G. Fischer, Jena, Germany, 1904).

    Google Scholar 

  28. Alzheimer, A. in Histologische und histopathologische Arbeiten über die Grosshirnrinde Vol. 3 (eds. Nissl, F., Alzheimer, A.) 401–562 (G. Fischer, Jena, Germany, 1910).

    Google Scholar 

  29. Hortega, P. R. El tercer elemento de los centros nerviosos. III. Naturaleza probable de la microglía [Spanish]. Bol. Soc. Esp. Biol. 8, 108–115 (1919).

    Google Scholar 

  30. Greter, M. & Merad, M. Regulation of microglia development and homeostasis. Glia 61, 121–127 (2013).

    PubMed  Google Scholar 

  31. Gomez Perdiguero, E., Schulz, C. & Geissmann, F. Development and homeostasis of “resident” myeloid cells: the case of the microglia. Glia 61, 112–120 (2013).

    PubMed  Google Scholar 

  32. Hong, S. et al. Complement and microglia mediate early synapse loss in Alzheimer mouse models. Science 352, 712–716 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  33. Paolicelli, R. C. et al. Synaptic pruning by microglia is necessary for normal brain development. Science 333, 1456–1458 (2011).

    CAS  PubMed  Google Scholar 

  34. Schafer, D. P. et al. Microglia sculpt postnatal neural circuits in an activity and complement-dependent manner. Neuron 74, 691–705 (2012).

    CAS  PubMed  PubMed Central  Google Scholar 

  35. Lue, L. F., Kuo, Y. M., Beach, T. & Walker, D. G. Microglia activation and anti-inflammatory regulation in Alzheimer’s disease. Mol. Neurobiol. 41, 115–128 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Neumann, H., Kotter, M. R. & Franklin, R. J. Debris clearance by microglia: an essential link between degeneration and regeneration. Brain 132, 288–295 (2009).

    CAS  PubMed  Google Scholar 

  37. Butovsky, O. et al. Microglia activated by IL-4 or IFN-gamma differentially induce neurogenesis and oligodendrogenesis from adult stem/progenitor cells. Mol. Cell. Neurosci. 31, 149–160 (2006).

    CAS  PubMed  Google Scholar 

  38. Parkhurst, C. N. et al. Microglia promote learning-dependent synapse formation through brain-derived neurotrophic factor. Cell 155, 1596–1609 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  39. Keren-Shaul, H. et al. A unique microglia type associated with restricting development of Alzheimer’s disease. Cell 169, 1276–1290 (2017).

    CAS  PubMed  Google Scholar 

  40. Matcovitch-Natan, O. et al. Microglia development follows a stepwise program to regulate brain homeostasis. Science 353, aad8670 (2016).

    PubMed  Google Scholar 

  41. Mathys, H. et al. Temporal tracking of microglia activation in neurodegeneration at single-cell resolution. Cell Rep. 21, 366–380 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  42. Chiu, I. M. et al. A neurodegeneration-specific gene-expression signature of acutely isolated microglia from an amyotrophic lateral sclerosis mouse model. Cell Rep. 4, 385–401 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  43. Wang, Y. et al. TREM2 lipid sensing sustains the microglial response in an Alzheimer’s disease model. Cell 160, 1061–1071 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  44. Vincenti, J. E. et al. Defining the microglia response during the time course of chronic neurodegeneration. J. Virol. 90, 3003–3017 (2015).

    PubMed  Google Scholar 

  45. Alibhai, J. et al. Distribution of misfolded prion protein seeding activity alone does not predict regions of neurodegeneration. PLoS Biol. 14, e1002579 (2016).

    PubMed  PubMed Central  Google Scholar 

  46. Gosselin, D. et al. An environment-dependent transcriptional network specifies human microglia identity. Science 356, eaal3222 (2017).

    PubMed  PubMed Central  Google Scholar 

  47. Butovsky, O. et al. Identification of a unique TGF-beta-dependent molecular and functional signature in microglia. Nat. Neurosci. 17, 131–143 (2014).

    CAS  PubMed  Google Scholar 

  48. Ofengeim, D. et al. RIPK1 mediates a disease-associated microglial response in Alzheimer’s disease. Proc. Natl Acad. Sci. USA 114, E8788–E8797 (2017).

    CAS  PubMed  Google Scholar 

  49. Deczkowska, A. et al. Disease-associated microglia: a universal immune sensor of neurodegeneration. Cell 173, 1073–1081 (2018).

    CAS  PubMed  Google Scholar 

  50. Kamphuis, W., Kooijman, L., Schetters, S., Orre, M. & Hol, E. M. Transcriptional profiling of CD11c-positive microglia accumulating around amyloid plaques in a mouse model for Alzheimer’s disease. Biochim. Biophys. Acta 1862, 1847–1860 (2016).

    CAS  PubMed  Google Scholar 

  51. Bouchon, A., Dietrich, J. & Colonna, M. Cutting edge: inflammatory responses can be triggered by TREM-1, a novel receptor expressed on neutrophils and monocytes. J. Immunol. 164, 4991–4995 (2000).

    CAS  PubMed  Google Scholar 

  52. Cannon, J. P., O’Driscoll, M. & Litman, G. W. Specific lipid recognition is a general feature of CD300 and TREM molecules. Immunogenetics 64, 39–47 (2012).

    CAS  PubMed  Google Scholar 

  53. Daws, M. R. et al. Pattern recognition by TREM-2: binding of anionic ligands. J. Immunol. 171, 594–599 (2003).

    CAS  PubMed  Google Scholar 

  54. Kawabori, M. et al. Triggering receptor expressed on myeloid cells 2 (TREM2) deficiency attenuates phagocytic activities of microglia and exacerbates ischemic damage in experimental stroke. J. Neurosci. 35, 3384–3396 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  55. Xing, J., Titus, A. R. & Humphrey, M. B. The TREM2-DAP12 signaling pathway in Nasu-Hakola disease: a molecular genetics perspective. Res. Rep. Biochem. 5, 89–100 (2015).

    PubMed  PubMed Central  Google Scholar 

  56. Peng, Q. et al. TREM2- and DAP12-dependent activation of PI3K requires DAP10 and is inhibited by SHIP1. Sci. Signal. 3, ra38 (2010).

    PubMed  PubMed Central  Google Scholar 

  57. Ulland, T. K. et al. TREM2 maintains microglial metabolic fitness in Alzheimer’s disease. Cell 170, 649–663 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  58. Turnbull, I. R. et al. Cutting edge: TREM-2 attenuates macrophage activation. J. Immunol. 177, 3520–3524 (2006).

    CAS  PubMed  Google Scholar 

  59. Piccio, L. et al. Blockade of TREM-2 exacerbates experimental autoimmune encephalomyelitis. Eur. J. Immunol. 37, 1290–1301 (2007).

    CAS  PubMed  Google Scholar 

  60. Wunderlich, P. et al. Sequential proteolytic processing of the triggering receptor expressed on myeloid cells-2 (TREM2) protein by ectodomain shedding and gamma-secretase-dependent intramembranous cleavage. J. Biol. Chem. 288, 33027–33036 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  61. Schlepckow, K. et al. An Alzheimer-associated TREM2 variant occurs at the ADAM cleavage site and affects shedding and phagocytic function. EMBO Mol. Med. 9, 1356–1365 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  62. Thornton, P. et al. TREM2 shedding by cleavage at the H157-S158 bond is accelerated for the Alzheimer’s disease-associated H157Y variant. EMBO Mol. Med. 9, 1366–1378 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  63. Feuerbach, D. et al. ADAM17 is the main sheddase for the generation of human triggering receptor expressed in myeloid cells (hTREM2) ectodomain and cleaves TREM2 after histidine 157. Preprint at https://www.biorxiv.org/content/early/2017/05/03/133751 (2017).

  64. Glebov, K., Wunderlich, P., Karaca, I. & Walter, J. Functional involvement of γ-secretase in signaling of the triggering receptor expressed on myeloid cells-2 (TREM2). J. Neuroinflammation 13, 17 (2016).

    PubMed  PubMed Central  Google Scholar 

  65. Paloneva, J. et al. Mutations in two genes encoding different subunits of a receptor signaling complex result in an identical disease phenotype. Am. J. Hum. Genet. 71, 656–662 (2002).

    CAS  PubMed  PubMed Central  Google Scholar 

  66. Klunemann, H. H. et al. The genetic causes of basal ganglia calcification, dementia, and bone cysts: DAP12 and TREM2. Neurology 64, 1502–1507 (2005).

    CAS  PubMed  Google Scholar 

  67. Hakola, H. P. Neuropsychiatric and genetic aspects of a new hereditary disease characterized by progressive dementia and lipomembranous polycystic osteodysplasia. Acta Psychiatr. Scand. 232, 1–173 (1972).

    CAS  Google Scholar 

  68. Cella, M. et al. Impaired differentiation of osteoclasts in TREM-2-deficient individuals. J. Exp. Med. 198, 645–651 (2003).

    CAS  PubMed  PubMed Central  Google Scholar 

  69. Poliani, P. L. et al. TREM2 sustains microglial expansion during aging and response to demyelination. J. Clin. Invest. 125, 2161–2170 (2015).

    PubMed  PubMed Central  Google Scholar 

  70. Otero, K. et al. Macrophage colony-stimulating factor induces the proliferation and survival of macrophages via a pathway involving DAP12 and beta-catenin. Nat. Immunol. 10, 734–743 (2009).

    CAS  PubMed  PubMed Central  Google Scholar 

  71. Zou, W., Reeve, J. L., Liu, Y., Teitelbaum, S. L. & Ross, F. P. DAP12 couples c-Fms activation to the osteoclast cytoskeleton by recruitment of Syk. Mol. Cell 31, 422–431 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  72. Guerreiro, R. et al. Novel compound heterozygous mutation in TREM2 found in a Turkish frontotemporal dementia-like family. Neurobiol. Aging 34, 2890 (2013).

    PubMed  PubMed Central  Google Scholar 

  73. Jin, S. C. et al. TREM2 is associated with increased risk for Alzheimer’s disease in African Americans. Mol. Neurodegener. 10, 19 (2015).

    PubMed  PubMed Central  Google Scholar 

  74. Jiang, T. et al. A rare coding variant in TREM2 increases risk for Alzheimer’s disease in Han Chinese. Neurobiol. Aging 42, 217 (2016).

    PubMed  Google Scholar 

  75. Huang, M. et al. Lack of genetic association between TREM2 and Alzheimer’s disease in East Asian population: a systematic review and meta-analysis. Am. J. Alzheimers Dis. Other Demen. 30, 541–546 (2015).

    PubMed  Google Scholar 

  76. Wang, Y. et al. TREM2-mediated early microglial response limits diffusion and toxicity of amyloid plaques. J. Exp. Med. 213, 667–675 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  77. Mazaheri, F. et al. TREM2 deficiency impairs chemotaxis and microglial responses to neuronal injury. EMBO Rep. 18, 1186–1198 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  78. Yuan, P. et al. TREM2 haplodeficiency in mice and humans impairs the microglia barrier function leading to decreased amyloid compaction and severe axonal dystrophy. Neuron 90, 724–739 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  79. Mildner, A. et al. Distinct and non-redundant roles of microglia and myeloid subsets in mouse models of Alzheimer’s disease. J. Neurosci. 31, 11159–11171 (2011).

    CAS  PubMed  Google Scholar 

  80. Condello, C., Yuan, P., Schain, A. & Grutzendler, J. Microglia constitute a barrier that prevents neurotoxic protofibrillar Aβ42 hotspots around plaques. Nat. Commun. 6, 6176 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  81. Bradshaw, E. M. et al. CD33 Alzheimer’s disease locus: altered monocyte function and amyloid biology. Nat. Neurosci. 16, 848–850 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  82. Heneka, M. T. et al. NLRP3 is activated in Alzheimer’s disease and contributes to pathology in APP/PS1 mice. Nature 493, 674–678 (2013).

    CAS  PubMed  Google Scholar 

  83. Venegas, C. et al. Microglia-derived ASC specks cross-seed amyloid-beta in Alzheimer’s disease. Nature 552, 355–361 (2017).

    CAS  PubMed  Google Scholar 

  84. Jay, T. R. et al. TREM2 deficiency eliminates TREM2+ inflammatory macrophages and ameliorates pathology in Alzheimer’s disease mouse models. J. Exp. Med. 212, 287–295 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  85. Jay, T. R. et al. Disease progression-dependent effects of TREM2 deficiency in a mouse model of Alzheimer’s disease. J. Neurosci. 37, 637–647 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  86. Lee, C. Y. et al. Elevated TREM2 gene dosage reprograms microglia responsivity and ameliorates pathological phenotypes in Alzheimer’s disease models. Neuron 97, 1032–1048 (2018).

    CAS  PubMed  Google Scholar 

  87. Carrasquillo, M. M. et al. A candidate regulatory variant at the TREM gene cluster associates with decreased Alzheimer’s disease risk and increased TREML1 and TREM2 brain gene expression. Alzheimers Dement. 13, 663–673 (2017).

    PubMed  Google Scholar 

  88. Leyns, C. E. et al. TREM2 deficiency attenuates neuroinflammation and protects against neurodegeneration in a mouse model of tauopathy. Proc. Natl Acad. Sci. USA 114, 11524–11529 (2017).

    CAS  PubMed  Google Scholar 

  89. Bemiller, S. M. et al. TREM2 deficiency exacerbates tau pathology through dysregulated kinase signaling in a mouse model of tauopathy. Mol. Neurodegener. 12, 74 (2017).

    PubMed  PubMed Central  Google Scholar 

  90. Kober, D. L. et al. Neurodegenerative disease mutations in TREM2 reveal a f unctional surface and distinct loss-of-function mechanisms. eLife 5, e20391 (2016).

    PubMed  PubMed Central  Google Scholar 

  91. Sudom, A. et al. Molecular basis for the loss-of-function effects of the Alzheimer’s disease-associated R47H variant of the immune receptor TREM2. J. Biol. Chem. 293, 12634–12646 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  92. Song, W. M. et al. Humanized TREM2 mice reveal microglia-intrinsic and -extrinsic effects of R47H polymorphism. J. Exp. Med. 215, 745–760 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  93. Yeh, F. L., Wang, Y., Tom, I., Gonzalez, L. C. & Sheng, M. TREM2 binds to apolipoproteins, including APOE and CLU/APOJ, and thereby facilitates uptake of amyloid-beta by microglia. Neuron 91, 328–340 (2016).

    CAS  PubMed  Google Scholar 

  94. Kleinberger, G. et al. TREM2 mutations implicated in neurodegeneration impair cell surface transport and phagocytosis. Sci. Transl Med. 6, 243ra286 (2014).

    Google Scholar 

  95. Ulrich, J. D., Ulland, T. K., Colonna, M. & Holtzman, D. M. Elucidating the role of TREM2 in Alzheimer’s disease. Neuron 94, 237–248 (2017).

    CAS  PubMed  Google Scholar 

  96. Borroni, B. et al. Heterozygous TREM2 mutations in frontotemporal dementia. Neurobiol. Aging 35, 934 (2014).

    PubMed  Google Scholar 

  97. Sirkis, D. W. et al. Rare TREM2 variants associated with Alzheimer’s disease display reduced cell surface expression. Acta Neuropathol. Commun. 4, 98 (2016).

    PubMed  PubMed Central  Google Scholar 

  98. Kleinberger, G. et al. The FTD-like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism. EMBO J. 36, 1837–1853 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  99. Atagi, Y. et al. Apolipoprotein E is a ligand for triggering receptor expressed on myeloid cells 2 (TREM2). J. Biol. Chem. 290, 26043–26050 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  100. Bailey, C. C., DeVaux, L. B. & Farzan, M. The triggering receptor expressed on myeloid cells 2 binds apolipoprotein E. J. Biol. Chem. 290, 26033–26042 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  101. Jendresen, C., Arskog, V., Daws, M. R. & Nilsson, L. N. The Alzheimer’s disease risk factors apolipoprotein E and TREM2 are linked in a receptor signaling pathway. J. Neuroinflammation 14, 59 (2017).

    PubMed  PubMed Central  Google Scholar 

  102. Zhao, Y. et al. TREM2 is a receptor for beta-amyloid that mediates microglial function. Neuron 97, 1023–1031 (2018).

    CAS  PubMed  Google Scholar 

  103. Lessard, C. B. et al. High affinity interactions and signal transduction between Aβ oligomers and TREM2. Preprint at https://www.biorxiv.org/content/early/2018/02/22/269787 (2018).

  104. Zhong, L. et al. Soluble TREM2 induces inflammatory responses and enhances microglial survival. J. Exp. Med. 214, 597–607 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  105. Wu, K. et al. TREM-2 promotes macrophage survival and lung disease after respiratory viral infection. J. Exp. Med. 212, 681–697 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  106. Hsieh, C. L. et al. A role for TREM2 ligands in the phagocytosis of apoptotic neuronal cells by microglia. J. Neurochem. 109, 1144–1156 (2009).

    CAS  PubMed  PubMed Central  Google Scholar 

  107. Zhong, L. et al. DAP12 stabilizes the C-terminal fragment of the triggering receptor expressed on myeloid cells-2 (TREM2) and protects against LPS-induced pro-inflammatory response. J. Biol. Chem. 290, 15866–15877 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  108. Ohrfelt, A. et al. Soluble TREM-2 in cerebrospinal fluid from patients with multiple sclerosis treated with natalizumab or mitoxantrone. Mult. Scler. 22, 1587–1595 (2016).

    PubMed  Google Scholar 

  109. Cooper-Knock, J. et al. A data-driven approach links microglia to pathology and prognosis in amyotrophic lateral sclerosis. Acta Neuropathol. Commun. 5, 23 (2017).

    PubMed  PubMed Central  Google Scholar 

  110. Suarez-Calvet, M. et al. sTREM2 cerebrospinal fluid levels are a potential biomarker for microglia activity in early-stage Alzheimer’s disease and associate with neuronal injury markers. EMBO Mol. Med. 8, 466–476 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  111. Piccio, L. et al. Cerebrospinal fluid soluble TREM2 is higher in Alzheimer disease and associated with mutation status. Acta Neuropathol. 131, 925–933 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  112. Heslegrave, A. et al. Increased cerebrospinal fluid soluble TREM2 concentration in Alzheimer’s disease. Mol. Neurodegener. 11, 3 (2016).

    PubMed  PubMed Central  Google Scholar 

  113. Suarez-Calvet, M. et al. Early changes in CSF sTREM2 in dominantly inherited Alzheimer’s disease occur after amyloid deposition and neuronal injury. Sci. Transl Med. 8, 369ra178 (2016).

    PubMed  PubMed Central  Google Scholar 

  114. Henjum, K. et al. Cerebrospinal fluid soluble TREM2 in aging and Alzheimer’s disease. Alzheimers Res. Ther. 8, 17 (2016).

    PubMed  PubMed Central  Google Scholar 

  115. Voytyuk, I., De Strooper, B. & Chavez-Gutierrez, L. Modulation of γ- and β-secretases as early prevention against Alzheimer’s disease. Biol. Psychiatry 83, 320–327 (2018).

    CAS  PubMed  Google Scholar 

  116. van Dyck, C. H. Anti-amyloid-beta monoclonal antibodies for Alzheimer’s disease: pitfalls and promise. Biol. Psychiatry 83, 311–319 (2018).

    PubMed  Google Scholar 

  117. Strittmatter, S. M. Emerging mechanisms in Alzheimer’s disease and their therapeutic implications. Biol. Psychiatry 83, 298–299 (2018).

    PubMed  Google Scholar 

  118. Griciuc, A. et al. Alzheimer’s disease risk gene CD33 inhibits microglial uptake of amyloid beta. Neuron 78, 631–643 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  119. Spangenberg, E. E. et al. Eliminating microglia in Alzheimer’s mice prevents neuronal loss without modulating amyloid-beta pathology. Brain 139, 1265–1281 (2016).

    PubMed  PubMed Central  Google Scholar 

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Acknowledgements

Review criteria

This Review serves as an overview of the current state of the field regarding triggering receptor expressed on myeloid cells 2 (TREM2) in Alzheimer disease (AD) pathogenesis, including the presentation of conflicting data. The authors primarily used PubMed to search the literature, focusing predominantly on the period between 2013, when TREM2 variants associated with an increased risk of AD were first reported, and the final submission date in February 2018. Supporting studies published before 2013 regarding AD and TREM2 were also reviewed. Search terms included “TREM2”, “TREM2 and Alzheimer’s disease”, “TREM2 and microglia”, “TREM2 and macrophages”, “Alzheimer’s disease” and “TREM2 and neurodegeneration”.

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Correspondence to Marco Colonna.

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Ulland, T.K., Colonna, M. TREM2 — a key player in microglial biology and Alzheimer disease. Nat Rev Neurol 14, 667–675 (2018). https://doi.org/10.1038/s41582-018-0072-1

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