{"id":212089,"date":"2025-04-22T14:14:59","date_gmt":"2025-04-22T19:14:59","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2025\/04\/trem2-and-strem2-in-alzheimers-disease-from-mechanisms-to-therapies"},"modified":"2025-04-22T14:14:59","modified_gmt":"2025-04-22T19:14:59","slug":"trem2-and-strem2-in-alzheimers-disease-from-mechanisms-to-therapies","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2025\/04\/trem2-and-strem2-in-alzheimers-disease-from-mechanisms-to-therapies","title":{"rendered":"TREM2 and sTREM2 in Alzheimer\u2019s disease: from mechanisms to therapies"},"content":{"rendered":"<p><a class=\"aligncenter blog-photo\" href=\"https:\/\/lifeboat.com\/blog.images\/trem2-and-strem2-in-alzheimers-disease-from-mechanisms-to-therapies2.jpg\"><\/a><\/p>\n<p>The metabolic fitness of microglia is markedly impaired in TREM2 knockout (KO) models [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 58\" title=\"Ulland TK, Song WM, Huang SC, Ulrich JD, Sergushichev A, Beatty WL, Loboda AA, Zhou Y, Cairns NJ, Kambal A, et al. TREM2 maintains microglial metabolic fitness in Alzheimer\u2019s disease. Cell. 2017;170:649&ndash;e663613.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR58\" id=\"ref-link-section-d30802922e888\">58<\/a>]. TREM2, through its adaptors DAP12 and DAP10, activates the mechanistic target of rapamycin (mTOR) signaling pathway, which plays a crucial role in regulating metabolic pathways and protein synthesis [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 11\" title=\"Wang S, Sudan R, Peng V, Zhou Y, Du S, Yuede CM, Lei T, Hou J, Cai Z, Cella M, et al. TREM2 drives microglia response to amyloid-beta via SYK-dependent and-independent pathways. Cell. 2022;185:4153&ndash;e41694119.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR11\" id=\"ref-link-section-d30802922e891\">11<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 58\" title=\"Ulland TK, Song WM, Huang SC, Ulrich JD, Sergushichev A, Beatty WL, Loboda AA, Zhou Y, Cairns NJ, Kambal A, et al. TREM2 maintains microglial metabolic fitness in Alzheimer\u2019s disease. Cell. 2017;170:649&ndash;e663613.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR58\" id=\"ref-link-section-d30802922e894\">58<\/a>]. Loss of TREM2 impairs mTOR activation, leading to reduced ATP production and biosynthesis. In vivo FDG-PET imaging of TREM2 KO and TREM2 T66M knock-in mice shows a significant reduction in cerebral glucose metabolism [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 67\" title=\"Kleinberger G, Brendel M, Mracsko E, Wefers B, Groeneweg L, Xiang X, Focke C, Deussing M, Suarez-Calvet M, Mazaheri F, et al. The FTD-like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism. EMBO J. 2017;36:1837&ndash;53.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR67\" id=\"ref-link-section-d30802922e897\">67<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 68\" title=\"Xiang X, Wind K, Wiedemann T, Blume T, Shi Y, Briel N, Beyer L, Biechele G, Eckenweber F, Zatcepin A, et al. Microglial activation states drive glucose uptake and FDG-PET alterations in neurodegenerative diseases. Sci Transl Med. 2021;13:eabe5640.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR68\" id=\"ref-link-section-d30802922e900\">68<\/a>]. This decrease may correlate with impaired glucose uptake by microglia. Supporting this, ex vivo measurements of isolated microglia from TREM2 KO animals reveal lower FDG uptake [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 68\" title=\"Xiang X, Wind K, Wiedemann T, Blume T, Shi Y, Briel N, Beyer L, Biechele G, Eckenweber F, Zatcepin A, et al. Microglial activation states drive glucose uptake and FDG-PET alterations in neurodegenerative diseases. Sci Transl Med. 2021;13:eabe5640.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR68\" id=\"ref-link-section-d30802922e904\">68<\/a>].<\/p>\n<p>Given the pivotal role of microglial metabolism in AD, targeting this process represents a promising therapeutic strategy. Agents such as interferon-\u03b3 (IFN-\u03b3) and cyclocreatine, which enhance ATP production, have been shown to restore microglial functions and mitigate AD pathology [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 58\" title=\"Ulland TK, Song WM, Huang SC, Ulrich JD, Sergushichev A, Beatty WL, Loboda AA, Zhou Y, Cairns NJ, Kambal A, et al. TREM2 maintains microglial metabolic fitness in Alzheimer\u2019s disease. Cell. 2017;170:649&ndash;e663613.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR58\" id=\"ref-link-section-d30802922e910\">58<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 65\" title=\"Baik SH, Kang S, Lee W, Choi H, Chung S, Kim JI, Mook-Jung I. A breakdown in metabolic reprogramming causes microglia dysfunction in Alzheimer\u2019s disease. Cell Metab. 2019;30:493&ndash;e507496.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR65\" id=\"ref-link-section-d30802922e913\">65<\/a>]. Notably, TREM2-activating antibodies boost microglial energy metabolism by promoting mitochondrial fatty acid and glucose oxidation [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 69\" title=\"van Lengerich B, Zhan L, Xia D, Chan D, Joy D, Park JI, Tatarakis D, Calvert M, Hummel S, Lianoglou S, et al. A TREM2-activating antibody with a blood-brain barrier transport vehicle enhances microglial metabolism in Alzheimer\u2019s disease models. Nat Neurosci. 2023;26:416&ndash;29.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR69\" id=\"ref-link-section-d30802922e916\">69<\/a>]. Moreover, translocator protein (TSPO)-PET and FDG-PET imaging have demonstrated that TREM2 activation enhances microglial activity and glucose metabolism in amyloid mouse models. Thus, targeting TREM2 and microglial metabolism may complement existing AD therapies, which primarily focus on amyloid clearance and synaptic dysfunction, providing a more comprehensive approach to disease intervention.<\/p>\n<p>Lipid metabolism is crucial for maintaining microglial functions and CNS homeostasis, influencing cellular membrane integrity, energy storage, and inflammatory responses. Emerging evidence identifies TREM2 as a key regulator of lipid metabolism in the brain. TREM2 binds a diverse range of lipids, including anionic and zwitterionic species such as sphingomyelin, phosphatidic acid, phosphatidylinositol, phosphatidylcholine, phosphatidylglycerol, phosphatidylserine (PtdSer) and sulfatide [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 49\" title=\"Wang Y, Cella M, Mallinson K, Ulrich JD, Young KL, Robinette ML, Gilfillan S, Krishnan GM, Sudhakar S, Zinselmeyer BH, et al. TREM2 lipid sensing sustains the microglial response in an Alzheimer\u2019s disease model. Cell. 2015;160:1061&ndash;71.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR49\" id=\"ref-link-section-d30802922e927\">49<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 53\" title=\"Cannon JP, O\u2019Driscoll M, Litman GW. Specific lipid recognition is a general feature of CD300 and TREM molecules. Immunogenetics. 2012;64:39&ndash;47.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR53\" id=\"ref-link-section-d30802922e930\">53<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 70\" title=\"Daws MR, Sullam PM, Niemi EC, Chen TT, Tchao NK, Seaman WE. Pattern recognition by TREM-2: binding of anionic ligands. J Immunol. 2003;171:594&ndash;9.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR70\" id=\"ref-link-section-d30802922e933\">70<\/a>]. Among these, PtdSer is the most abundant negatively charged phospholipid in the inner leaflet of the plasma membrane in eukaryotic cells [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 71\" title=\"Leventis PA, Grinstein S. The distribution and function of phosphatidylserine in cellular membranes. Annu Rev Biophys. 2010;39:407&ndash;27.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR71\" id=\"ref-link-section-d30802922e936\">71<\/a>]. In neurodegenerative conditions, PtdSer externalization on damaged or apoptotic neurons serves as an \u201ceat-me\u201d signal, triggering TREM2-dependent microglial synaptic pruning and cell clearance [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 72\" title=\"Rueda-Carrasco J, Sokolova D, Lee SE, Childs T, Jurcakova N, Crowley G, De Schepper S, Ge JZ, Lachica JI, Toomey CE, et al. Microglia-synapse engulfment via PtdSer-TREM2 ameliorates neuronal hyperactivity in Alzheimer\u2019s disease models. EMBO J. 2023;42:e113246.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR72\" id=\"ref-link-section-d30802922e939\">72<\/a>]. Super-resolution microscopy and in vivo imaging studies have demonstrated that A\u03b2 oligomer-induced hyperactive synapses expose PtdSer, marking them for TREM2-mediated engulfment, which helps mitigate neuronal hyperactivity in AD models. Additionally, individuals carrying TREM2 loss-of-function variants exhibit an accumulation of apoptotic-like synapses [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 72\" title=\"Rueda-Carrasco J, Sokolova D, Lee SE, Childs T, Jurcakova N, Crowley G, De Schepper S, Ge JZ, Lachica JI, Toomey CE, et al. Microglia-synapse engulfment via PtdSer-TREM2 ameliorates neuronal hyperactivity in Alzheimer\u2019s disease models. EMBO J. 2023;42:e113246.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR72\" id=\"ref-link-section-d30802922e943\">72<\/a>], underscoring TREM2\u2019s essential role in synaptic homeostasis during early AD pathology. Beyond synaptic pruning, TREM2 facilitates the recognition and clearance of damaged cells. Notably, over-expression of TREM2 in non-phagocytic cells, such as Chinese hamster ovary (CHO) and HEK293 cells, enables them to engulf apoptotic neurons, highlighting TREM2\u2019s function in lipid sensing and phagocytosis [<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 16\" title=\"Kleinberger G, Yamanishi Y, Suarez-Calvet M, Czirr E, Lohmann E, Cuyvers E, Struyfs H, Pettkus N, Wenninger-Weinzierl A, Mazaheri F, et al. TREM2 mutations implicated in neurodegeneration impair cell surface transport and phagocytosis. Sci Transl Med. 2014;6:243ra286.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR16\" id=\"ref-link-section-d30802922e946\">16<\/a>, <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 73\" title=\"Hsieh CL, Koike M, Spusta SC, Niemi EC, Yenari M, Nakamura MC, Seaman WE. A role for TREM2 ligands in the phagocytosis of apoptotic neuronal cells by microglia. J Neurochem. 2009;109:1144&ndash;56.\" href=\"https:\/\/molecularneurodegeneration.biomedcentral.com\/articles\/10.1186\/s13024-025-00834-z#ref-CR73\" id=\"ref-link-section-d30802922e949\">73<\/a>]. This broad lipid-binding capability underscores TREM2\u2019s critical role in modulating microglial responses to neurodegenerative insults and preserving neuronal health.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The metabolic fitness of microglia is markedly impaired in TREM2 knockout (KO) models [58]. TREM2, through its adaptors DAP12 and DAP10, activates the mechanistic target of rapamycin (mTOR) signaling pathway, which plays a crucial role in regulating metabolic pathways and protein synthesis [11, 58]. Loss of TREM2 impairs mTOR activation, leading to reduced ATP production [\u2026]<\/p>\n","protected":false},"author":661,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,1495,47],"tags":[],"class_list":["post-212089","post","type-post","status-publish","format-standard","hentry","category-biotech-medical","category-health","category-neuroscience"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/212089","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/661"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=212089"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/212089\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=212089"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=212089"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=212089"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}