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Cited by 37Neuroinflammation and Neurodegeneration MechanismsPhagocytosis and Immune RegulationAlzheimer's disease research and treatments

PLCγ2 regulates TREM2 signalling and integrin-mediated adhesion and migration of human iPSC-derived macrophages

Open access
Obst, Juliane, Hall-Roberts, Hazel L., Smith, Thomas B., Kreuzer, Mira, Magno, Lorenza, Di Daniel, Elena, Davis, John B., Mead, Emma·2021·Scientific Reports
DOI 10.1038/s41598-021-96144-7PMC PMC8494732
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Abstract

Human genetic studies have linked rare coding variants in microglial genes, such as TREM2 , and more recently PLCG2 to Alzheimer’s disease (AD) pathology. The P522R variant in PLCG2 has been shown to confer protection for AD and to result in a subtle increase in enzymatic activity. PLCγ2 is a key component of intracellular signal transduction networks and induces Ca 2+ signals downstream of many myeloid cell surface receptors, including TREM2. To explore the relationship between PLCγ2 and TREM2 and the role of PLCγ2 in regulating immune cell function, we generated human induced pluripotent stem cell (iPSC)- derived macrophages from isogenic lines with homozygous PLCG2 knockout (Ko). Stimulating TREM2 signalling using a polyclonal antibody revealed a complete lack of calcium flux and IP1 accumulation in PLCγ2 Ko cells, demonstrating a non-redundant role of PLCγ2 in calcium release downstream of TREM2. Loss of PLCγ2 led to broad changes in expression of several macrophage surface markers and phenotype, including reduced phagocytic activity and survival, while LPS-induced secretion of the inflammatory cytokines TNFα and IL-6 was unaffected. We identified additional deficits in PLCγ2- deficient cells that compromised cellular adhesion and migration. Thus, PLCγ2 is key in enabling divergent cellular functions and might be a promising target to increase beneficial microglial functions.

AI snapshot

Written from the paper’s full text.

TL;DR

In isogenic human iPSC-derived macrophages, PLCγ2 knockout abolished TREM2-evoked Ca²⁺ flux and IP1 production while leaving upstream SYK phosphorylation largely intact, and it reduced survival, phagocytosis, adhesion/spreading, and migration. The authors conclude PLCγ2 is a non-redundant effector downstream of TREM2 and a regulator of integrin-mediated macrophage functions.

Key findings

  • TREM2 ligation with AF1828 induced SYK phosphorylation, Ca²⁺ flux, and IP1 accumulation in Parent cells; Ca²⁺ and IP1 responses were absent in TREM2 KO and PLCγ2 KO cells, while SYK phosphorylation upstream of PLCγ2 was not significantly reduced in PLCγ2 KO cells and ERK1/2 phosphorylation upon TREM2 ligation was not significantly different (n = 3–4).
  • PLCγ2 KO macrophages showed reduced TREM2 protein and soluble TREM2, lower CD11b, higher CD14, and altered morphology (higher roundness, smaller area); they had reduced survival (slightly increased death under normal culture and earlier death without M-CSF), reduced phagocytosis of pHrodo-labelled synaptosomes and dead SHSY5Y cells, but unaffected LPS-induced TNFα and IL-6 secretion (n = 3–4).
  • Adhesion and spreading were impaired on uncoated plastic, vitronectin, laminin, collagen type I, and fibrinogen; fibronectin rescued adhesion but not spreading. Adhesion-induced SYK phosphorylation was delayed and ERK1/2 phosphorylation was weakened in PLCγ2 KO cells. qRT-PCR showed reduced ITGB1, ITGB2, ITGB3, ITGB5, and FN1, with alpha-integrin subunits unchanged (n = 3).
  • Migration was reduced in PLCγ2 KO cells: non-directional motility was impaired, and directed migration toward C5a (3 nM) and ATP (1 mM) was significantly lower than in Parent cells (n = 4).

Methods

  • Isogenic BIONi010-C human iPSC lines (Parent, TREM2 KO, and three PLCγ2 KO clones 20, 53, 93 generated by CRISPR-Cas9) were differentiated into primitive, tissue-type macrophages using an embryoid body protocol with BMP4, VEGF, SCF, and M-CSF.
  • Assays included Western blot, HTRF for IP1 and pSYK, FLIPR Ca²⁺ assay, AlphaLISA for soluble TREM2, flow cytometry, RNAscope, qRT-PCR, survival assay, live-cell phagocytosis, adhesion on ECM substrates, transwell migration, and TNFα/IL-6 ELISA.
  • Data are shown as mean ± SEM and analysed with two-way ANOVA followed by Bonferroni’s test, one-way ANOVA followed by Bonferroni’s test, or Student’s t-test; significance was set at p < 0.05.

Limitations

  • Stated: lower TREM2 surface expression in PLCγ2 KO cells could account for changes in signalling and phenotype; the authors cannot exclude that reduced phagocytosis is due to reduced TREM2 surface expression, and note the TREM2 antibody is a high-affinity ligand that may saturate signalling even when receptor numbers are reduced, whereas phagocytic cargo are low-affinity TREM2 ligands.
  • Stated: the severe adhesion phenotype is most likely due to transcriptional downregulation of β-integrin receptor subunits, perhaps combined with defective integrin downstream signalling; further research is needed to determine the precise mechanisms by which PLCγ2 impacts integrin and ECM expression.
  • Evident from the text: experiments use iPSC-derived macrophages (a microglia-like model) rather than brain microglia; most functional data are shown for representative PLCγ2 KO clone 20 when not otherwise stated, although three clones were tested; no in vivo validation or rescue experiments are reported.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41598-021-96144-7

Cites

59 of 59 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

38 of 53 cited sources checked · 19 supported · 1 flagged · accuracy not yet measured

  • Interpretationown data

    LPS-induced secretion of TNFα and other inflammatory cytokines is not affected in the absence of PLCγ2.

    “As such, our results are in line with the observation that LPS-induced secretion of TNFα and other inflammatory cytokines is not affected in the absence of PLCγ2.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [44] Zanoni, I. et al. CD14 controls the LPS-induced endocytosis of Toll-like receptor 4. Cell 147, 868–880 (2011). source

      The Results section on CD14-dependent endocytosis reports that TNFα production was unaffected in PLCγ2-deficient cells. It does not establish that other inflammatory cytokines were unaffected; in the same passage, IFN expression was deficient. No page number is available in our copy. (LLM, conf=0.90)

      Experimental — accuracy not yet measured
    • cites [45] Chiang, C. Y., Veckman, V., Limmer, K. & David, M. Phospholipase Cγ-2 and intracellular calcium are required for lipopolysaccharide-induced toll-like receptor 4 (TLR4) endocytosis and interferon regulatory factor 3 (IRF3) activation. J. Biol. Chem. 287, 3704–3709 (2012). source

      In “Intracellular Calcium Regulates LPS-induced ISG Expression” (page not provided), the paper reports that PLCγ2-knockout macrophages produced more TNFα after LPS stimulation, not an unaffected amount. It also reports similar or slightly higher expression of some inflammatory cytokine genes, but gene expression does not establish that their secretion was unaffected. (LLM, conf=0.87)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisecitation

    Rare coding variants in microglial genes such as TREM2 and PLCG2 are linked to Alzheimer's disease pathology.

    “Human genetic studies have linked rare coding variants in microglial genes, such as TREM2, and more recently PLCG2 to Alzheimer’s disease (AD) pathology.”
    • Also stated in: § Introduction · plain
      “Amongst the polymorphisms discovered are rare coding variants in genes encoding Triggering Receptor Expressed on Myeloid cells 2 (TREM2) and Phospholipase Cγ2 (PLCγ2)2–4.”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [2] Guerreiro, R. et al. TREM2 Variants in Alzheimer’s Disease. N. Engl. J. Med. 368, 117–127 (2013). source

      The Abstract Results and Conclusions report an association between rare TREM2 variants and Alzheimer’s disease, and the Discussion places TREM2 in microglial responses. The paper does not report a PLCG2 variant association, so it supports only the TREM2 part of the claim. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [3] Jonsson, T. et al. Variant of TREM2 associated with the risk of Alzheimer’s disease. N. Engl. J. Med. 368, 107–116 (2013). source

      The Results (Association of Variant with Alzheimer’s Disease; page unavailable) report that a rare coding variant in TREM2 is significantly associated with Alzheimer’s disease risk, and the Discussion identifies TREM2 as expressed in microglia. Our copy does not address PLCG2, so it supports the TREM2 part but not the full claim attributed to this source. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [4] 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). source
  • Premisecitation

    Studying microglia using human cell models such as iPSC-derived cells is vital given species-specific differences in microglial responses between human and mouse cells.

    “Studying microglia using human cell models such as iPSC-derived cells is vital given the species-specific differences in microglial responses between human and mouse cells27.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [27] Zhou, Y. et al. Human and mouse single-nucleus transcriptomics reveal TREM2-dependent and TREM2-independent cellular responses in Alzheimer’s disease. Nat. Med. 26, 131–142 (2020). source
  • Findingcitation

    Genetic deficiency of PLCγ2 significantly reduced phagocytosis of cortical synaptosomes and dead cells.

    “Similarly to TREM2 Ko macrophages23, genetic deficiency of PLCγ2 significantly reduced phagocytosis of both cargos”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [23] Hall-Roberts, H. et al. TREM2 Alzheimer’s variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimer’s Res. Ther. 12, 1–27 (2020). source
  • Findingown data

    Loss of PLCγ2 leads to reduced survival in iPSC-derived macrophages.

    “including reduced phagocytic activity and survival”
    • Also stated in: § PLCγ2 Ko iPSC-macrophages display deficits in survival and phagocytosis, but not LPS-induced TNFα and IL-6 secretion · plain
      “PLCγ2 Ko cells showed a reduced survival rate”
    Quote in the paperSubstantial claim
  • May combine two claims. 43
  • Classified as probably not a substantial claim. 29

  • May combine two claims.

    Premisecitation

    The TREM2 activating antibody AF1828 induces downstream signalling including SYK activation and release of calcium from intracellular stores.

    “In order to stimulate TREM2 we used a TREM2 activating antibody (R&D systems, AF1828) that induces downstream signalling including SYK activation and release of calcium from intracellular stores23,31.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [23] Hall-Roberts, H. et al. TREM2 Alzheimer’s variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimer’s Res. Ther. 12, 1–27 (2020). source
    • cites [31] Varnum, M. M. et al. A split-luciferase complementation, real-time reporting assay enables monitoring of the disease-associated transmembrane protein TREM2 in live cells. J. Biol. Chem. 292, 10651–10663 (2017). source

  • May combine two claims.

    Premisecitation

    TREM2 signals through PLCγ2 to mediate cell survival, phagocytosis, processing of neuronal debris and lipid metabolism.

    “TREM2 belongs to the same interaction network of immune-response genes implicated in AD as PLCγ24 and has been recently shown to signal through PLCγ2 to mediate cell survival, phagocytosis, processing of neuronal debris and lipid metabolism26.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [4] 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). source

      The paper’s TREM2 discussion (section labeled Abstract; page not provided) says TREM2–DAP12 signaling influences PLCγ2 activity and participates in recognition of membrane debris, leading to microglial activation and proliferation. It does not establish that signaling through PLCγ2 mediates cell survival, phagocytosis, neuronal-debris processing, or lipid metabolism. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [26] Andreone, B. J. et al. Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat. Neurosci. 23, 927–938 (2020). source

  • May combine two claims.

    Premisecitation

    The P522R variant in PLCG2 confers protection for Alzheimer's disease and results in a subtle increase in enzymatic activity.

    “The P522R variant in PLCG2 has been shown to confer protection for AD and to result in a subtle increase in enzymatic activity.”
    • Also stated in: § Introduction · plain
      “The missense variant P522R in PLCG2 (rs72824905-G, P = 5.38 × 10−10, OR = 0.68) was shown to be protective, not only in the context of AD4,5, but also in other neurodegenerative diseases such as frontotemporal dementia and dementia with Lewy bodies6.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [4] 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). source

      The passage labeled Abstract reports that PLCG2 p.P522R is associated with decreased risk of late-onset Alzheimer’s disease (OR=0.68). It describes PLCG2 as an enzyme, but does not report that p.P522R subtly increases its enzymatic activity; the discussion of altered signaling concerns other PLCG2 variants. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [5] Conway, O. J. et al. ABI3 and PLCG2 missense variants as risk factors for neurodegenerative diseases in Caucasians and African Americans. Mol. Neurodegener. 13, 1–12 (2018). source

      The Conclusions identify PLCG2_rs72824905-G (p.Pro522Arg) as a protective factor for Alzheimer's disease. The Discussion says this variant is expected to increase PLCγ2 signaling activity, but does not report a measured, subtle increase in its enzymatic activity. Page numbers are not available in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [6] van der Lee, S. J. et al. A nonsynonymous mutation in PLCG2 reduces the risk of Alzheimer’s disease, dementia with Lewy bodies and frontotemporal dementia, and increases the likelihood of longevity. Acta Neuropathol. 138, 237–250 (2019). source

      The Discussion reports that this PLCG2 variant was associated with reduced Alzheimer’s disease risk and that the authors replicated the protective association. It also reports a slight increase in activity from earlier functional experiments, but says those findings need confirmation; describing the activity increase as a demonstrated result overstates the evidence. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    These cells closely resemble human foetal microglia with regards to transcriptional signature and express high levels of microglial genes.

    “These cells closely resemble human foetal microglia with regards to transcriptional signature and express high levels of microglial genes29,30.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [29] Haenseler, W. et al. A highly efficient human pluripotent stem cell microglia model displays a neuronal-co-culture-specific expression profile and inflammatory response. Stem Cell Rep. 8, 1727–1742 (2017). source
    • cites [30] Buchrieser, J., James, W. & Moore, M. D. Human induced pluripotent stem cell-derived macrophages share ontogeny with myb-independent tissue-resident macrophages. Stem Cell Rep. 8, 334–345 (2017). source

      The Abstract describes iPSC-derived macrophages as developmentally related to tissue-resident macrophages, including microglia. The Results report a tissue-resident gene-expression pattern compared with adult blood monocytes, but do not compare these cells’ transcriptional signature with human foetal microglia or establish high expression of microglia-specific genes. The Introduction’s foetal comparison concerns liver-derived monocytes/macrophages, not microglia. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The P522R variant in PLCG2 is protective not only in Alzheimer's disease but also in other neurodegenerative diseases such as frontotemporal dementia and dementia with Lewy bodies.

    “The missense variant P522R in PLCG2 (rs72824905-G, P = 5.38 × 10−10, OR = 0.68) was shown to be protective, not only in the context of AD4,5, but also in other neurodegenerative diseases such as frontotemporal dementia and dementia with Lewy bodies6.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [4] 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). source
    • cites [5] Conway, O. J. et al. ABI3 and PLCG2 missense variants as risk factors for neurodegenerative diseases in Caucasians and African Americans. Mol. Neurodegener. 13, 1–12 (2018). source

      The Results report a protective association of PLCG2 P522R with Alzheimer’s disease (OR = 0.56, p = 0.008). For dementia with Lewy bodies, the association was only suggestive, not significant (OR = 0.32, p = 0.124). The paper’s listed disease cohorts do not include frontotemporal dementia, so it does not support that part of the claim. Page numbers are unavailable in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [6] van der Lee, S. J. et al. A nonsynonymous mutation in PLCG2 reduces the risk of Alzheimer’s disease, dementia with Lewy bodies and frontotemporal dementia, and increases the likelihood of longevity. Acta Neuropathol. 138, 237–250 (2019). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PLCγ2 is a signalling enzyme activated through tyrosine phosphorylation by receptor and non-receptor kinases.

    “PLCγ2 is a signalling enzyme activated through tyrosine phosphorylation by receptor and non-receptor kinases7.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [7] Sue Goo Rhee & Yun Soo Bae. Regulation of phosphoinositide-specific phospholipase C isozymes. J. Biol. Chem. 272, 15045–15048 (1997). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    TREM2 is a cell-surface receptor implicated in microglial functions such as phagocytosis, chemotaxis and survival.

    “TREM2 is a cell-surface receptor of the immunoglobulin superfamily implicated in a variety of microglial functions, such as phagocytosis, chemotaxis and survival21–23.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [21] Takahashi, K., Rochford, C. D. P. & Neumann, H. Clearance of apoptotic neurons without inflammation by microglial triggering receptor expressed on myeloid cells-2. J. Exp. Med. 201, 647–657 (2005). source

      The Results sections on TREM2 expression, phagocytosis, and CCR7-dependent migration show that TREM2 is expressed on microglia and is implicated in their phagocytosis and chemotaxis (page numbers unavailable). The passages do not establish a role in microglial survival; the cited copy also does not identify TREM2 as a member of the immunoglobulin superfamily. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [22] Mazaheri, F. et al. TREM2 deficiency impairs chemotaxis and microglial responses to neuronal injury. EMBO Rep. 18, 1186–1198 (2017). source
    • cites [23] Hall-Roberts, H. et al. TREM2 Alzheimer’s variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimer’s Res. Ther. 12, 1–27 (2020). source

  • Classified as probably not a substantial claim.

    Premisecitation

    TREM2 associates with DAP12 to induce signal transduction, including recruitment and activation of SYK and calcium flux.

    “TREM2 associates with the immunoreceptor tyrosine-based activation motif (ITAM)–containing adaptor protein DAP12 to induce signal transduction, including recruitment and activation of spleen tyrosine kinase (SYK) and calcium flux24,25.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [24] Kober, D. L. & Brett, T. J. TREM2-Ligand Interactions in Health and Disease. J. Mol. Biol. 429, 1607–1629 (2017). source
    • cites [25] Bouchon, A., Hernández-Munain, C., Cella, M. & Colonna, M. A DAP12-mediated pathway regulates expression of CC chemokine receptor 7 and maturation of human dendritic cells. J. Exp. Med. 194, 1111–1122 (2001). source

      The Results (page not specified) show that TREM-2 associates with DAP12 and that TREM-2 ligation causes calcium flux in human monocyte-derived dendritic cells. The Discussion identifies DAP12 as an ITAM-containing adaptor and reports PTK and ERK signaling, but our copy does not show recruitment or activation of SYK by TREM-2. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    PLCγ2 expression is largely restricted to hematopoietic cells and regulates specific responses downstream of several immune receptors.

    “While PLCγ1 is ubiquitously expressed and regulates growth factor signalling in a variety of cell types, expression of PLCγ2 is largely restricted to hematopoietic cells, and regulates specific responses downstream of several immune receptors8.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [8] Koss, H., Bunney, T. D., Behjati, S. & Katan, M. Dysfunction of phospholipase C g in immune disorders and cancer. Trends Biochem. Sci. 39, 603–611 (2014). source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Phagocytic activity of iPSC-derived microglia-like cells has recently been shown to be reduced by PLCγ2 deficiency, whilst phagocytosis was enhanced in BMDMs expressing P522R.

    “Phagocytic activity of iPSC-derived microglia-like cells has recently been shown to be reduced by PLCγ2 deficiency26, whilst phagocytosis was enhanced in bone marrow-derived macrophages that express the hypermorphic P522R variant19.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [26] Andreone, B. J. et al. Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat. Neurosci. 23, 927–938 (2020). source
    • cites [19] Takalo, M. et al. The Alzheimer’s disease-associated protective Plcγ2-P522R variant promotes immune functions. Mol. Neurodegener. 15, 52 (2020). source

      The Findings section reports approximately 45% higher phagocytic activity in P522R knock-in bone marrow-derived macrophages than in wild-type cells, but says the difference was not statistically significant (Fig. 1e). The cited paper therefore supports the direction of the observation, not an unqualified claim that phagocytosis was enhanced in those cells. The iPSC-derived microglia claim has a separate citation and is not judged here. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Both synaptosomes and dead SHSY5Y expose surface phosphatidylserine and are taken up by iPSC-derived macrophages at least partially via TREM2-dependent mechanisms.

    “Both substrates expose surface phosphatidylserine and were recently shown to be taken up by iPSC-derived macrophages at least partially via TREM2-dependent mechanisms23.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [23] Hall-Roberts, H. et al. TREM2 Alzheimer’s variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimer’s Res. Ther. 12, 1–27 (2020). source

  • May combine two claims.

    Premisecitation

    A TREM2-dependent survival defect has been shown in TREM2 Ko iPSC-derived microglia-like cells, a deficit also present in cells lacking PLCγ2.

    “Previously, a TREM2-dependent survival defect has been shown in TREM2 Ko iPSC-derived microglia-like cells23,26, a deficit that is also present in cells lacking PLCγ226.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [23] Hall-Roberts, H. et al. TREM2 Alzheimer’s variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimer’s Res. Ther. 12, 1–27 (2020). source

      The Results section (page not available) reports a small but significant increase in cell death in TREM2-knockout iPSC-derived macrophages after M-CSF withdrawal, supporting a survival defect in this microglia-like model under that condition. The paper does not report a survival defect in PLCγ2-deficient cells; its Discussion mentions PLCG2 knockout in connection with shared dysregulated genes, not survival. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [26] Andreone, B. J. et al. Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat. Neurosci. 23, 927–938 (2020). source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Previous reports demonstrate involvement of SYK-dependent signalling pathways downstream of integrin in neutrophils and macrophages and a role of PLCγ2 in integrin-mediated neutrophil functions.

    “Previous reports demonstrating the involvement of SYK-dependent signalling pathways downstream of integrin in neutrophils and macrophages32 and specifically the role of PLCγ2 in integrin-mediated neutrophil functions33”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [32] Abram, C. L., Hu, Y., Lanier, L. L. & Lowell, C. A. Integrin signaling in neutrophils and macrophages uses adaptors containing immunoreceptor tyrosine-based activation motifs. 7, 1326–1333 (2006).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [33] Jakus, Z., Simon, E., Frommhold, D., Sperandio, M. & Mocsai, A. Critical role of phospholipase C ␥ 2 in integrin and Fc receptor-mediated neutrophil functions and the eff ector phase of autoimmune arthritis. J. Exp. Med. 206, 577–593 (2009). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PLCγ2 has been implicated in driving inflammatory responses in mouse BMDMs and iPSC microglia-like cells, via TLR and inflammasome activation.

    “In addition to mediating TREM2-dependent signalling, PLCγ2 has been implicated in driving inflammatory responses in mouse BMDMs and in iPSC microglia-like cells, via TLR and inflammasome activation19,26.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [19] Takalo, M. et al. The Alzheimer’s disease-associated protective Plcγ2-P522R variant promotes immune functions. Mol. Neurodegener. 15, 52 (2020). source

      In the Findings section (page not supplied), the paper reports enhanced cytokine release from stimulated mouse BMDMs and cites earlier work linking PLCγ2 depletion to impaired inflammatory responses in iPSC-derived microglia. It also says PLCγ2 mediates inflammatory responses through Toll-like receptors. The paper does not establish inflammasome activation as the mechanism for those cellular responses. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [26] Andreone, B. J. et al. Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat. Neurosci. 23, 927–938 (2020). source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    PLCγ2 is similarly required in other peripheral immune cells to enable calcium mobilization upon B cell receptor activation using anti-IgM, FcεR ligation by IgE in mast cells, and FcγR activation in macrophages.

    “This observation adds to previous reports showing that PLCγ2 is similarly required in other peripheral immune cells to enable calcium mobilization upon B cell receptor activation using anti-IgM38, as well as FcεR ligation by IgE in mast cells and FcγR activation in macrophages10.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [38] Dou, Y. et al. Microglial migration mediated by ATP-induced ATP release from lysosomes. Cell Res. 22, 1022–1033 (2012). source

      The section on Ca²⁺-dependent lysosomal exocytosis reports ATP-induced calcium elevations in microglia, not PLCγ2-dependent responses to immune-receptor activation. Searches for PLCγ2, anti-IgM, FcεR and FcγR found no passage addressing the attributed claim about B cells, mast cells or macrophages. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites [10] Wen, R., Jou, S.-T., Chen, Y., Hoffmeyer, A. & Wang, D. Phospholipase Cγ2 Is Essential for Specific Functions of FcεR and FcγR. J. Immunol. 169, 6743–6752 (2002). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Genomic integrity of iPSC lines was verified by Illumina Omniexpress 24 v1.2 SNP microarray analysis.

    “An Illumina Omniexpress 24 v1.2 SNP microarray analysis was performed to verify genomic integrity, as previously described in Haenseler et al.29.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [29] Haenseler, W. et al. A highly efficient human pluripotent stem cell microglia model displays a neuronal-co-culture-specific expression profile and inflammatory response. Stem Cell Rep. 8, 1727–1742 (2017). source

      The Results section’s Figure 2 caption describes Illumina HT12v4 transcriptome analysis, not an OmniExpress SNP microarray used to verify genomic integrity. Searches for “OmniExpress,” “SNP microarray analysis,” and genomic-integrity testing found no passage in our copy describing the claimed procedure; page numbers were unavailable. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PLCγ2 was involved in signalling downstream of Bruton's tyrosine kinase (Btk) leading to Mac-1 activation and neutrophil recruitment in a mouse model of sterile inflammation.

    “PLCγ2 was involved in signalling downstream of Bruton’s tyrosine kinase (Btk) leading to Mac-1 activation and neutrophil recruitment in a mouse model of sterile inflammation52.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [52] Volmering, S., Block, H., Boras, M., Lowell, C. A. & Zarbock, A. The Neutrophil Btk Signalosome Regulates Integrin Activation during Sterile Inflammation. Immunity 44, 73–87 (2016). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In neutrophils, PLCγ2 mediates intracellular mobilization and influx of Ca2+ upon engagement of β2 integrin.

    “In neutrophils, PLCγ2 was implicated in mediating intracellular mobilization and influx of Ca2+ upon engagement of β2 integrin46.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [46] Hellberg, C., Molony, L., Zheng, L. & Andersson, T. Ca2+ signalling mechanisms of the β2 integrin on neutrophils: Involvement of phospholipase Cγ2 and Ins(1,4,5)P3. Biochem. J. 317, 403–409 (1996). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PLCγ2 is required to facilitate adhesion-dependent neutrophil activation and spreading upon integrin ligation.

    “It was shown that PLCγ2 was required to facilitate adhesion-dependent neutrophil activation and spreading upon integrin ligation33.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [33] Jakus, Z., Simon, E., Frommhold, D., Sperandio, M. & Mocsai, A. Critical role of phospholipase C ␥ 2 in integrin and Fc receptor-mediated neutrophil functions and the eff ector phase of autoimmune arthritis. J. Exp. Med. 206, 577–593 (2009). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Local changes in intracellular calcium play a critical role in regulating cell migration and chemotaxis in diverse cell types.

    “Local changes in intracellular calcium play a critical role in regulating cell migration and chemotaxis in diverse cell types48–50.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [48] Wei, C. et al. Calcium flickers steer cell migration. Nature 457, 901–905 (2009). source
    • cites [49] Evans, J. H. & Falke, J. J. Ca2+ influx is an essential component of the positive-feedback loop that maintains leading-edge structure and activity in macrophages. Proc. Natl. Acad. Sci. U. S. A. 104, 16176–16181 (2007). source

      The Discussion reports that calcium influx is essential for leading-edge activity in RAW macrophages and cites earlier evidence linking calcium entry to directed migration in neutrophils. It also says further studies are needed to determine whether this applies to other migrating cells. The claim's extension to diverse cell types is therefore not established by this paper. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [50] Tsai, F. C. & Meyer, T. Ca2+ pulses control local cycles of lamellipodia retraction and adhesion along the front of migrating cells. Curr. Biol. 22, 837–842 (2012). source

      The Results and Discussion (page not available) show that local Ca2+ pulses regulate retraction and adhesion in migrating human endothelial cells and suggest a role in migration and chemotaxis. The paper cites evidence concerning other cell types, but its own finding is limited to endothelial cells; it does not establish that local calcium changes play a critical role in chemotaxis across diverse cell types. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Recruitment of PLCγ2 to the membrane has been observed during chemotaxis of neutrophils, with PLCγ2 localised to the leading edge of migrating cells.

    “Recruitment of PLCγ2 to the membrane, a well-characterized mechanism of PLC activation, has been observed during chemotaxis of neutrophils, with PLCγ2 being localised to the leading edge of migrating cells51.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [51] Xu, X. et al. GPCR-Mediated PLCβγ/PKCβ/PKD Signaling Pathway Regulates the Cofilin Phosphatase Slingshot 2 in Neutrophil Chemotaxis. Mol. Biol. Cell. 26, 874–886 (2015). source

  • May combine two claims.

    Findingown data

    Loss of PLCγ2 compromises cellular adhesion and migration in iPSC-derived macrophages.

    “We identified additional deficits in PLCγ2- deficient cells that compromised cellular adhesion and migration.”
    • Also stated in: § Adhesion and spreading on substrates of the extracellular matrix is impaired in PLCγ2 Ko cells · plain
      “PLCγ2 Ko cells showed impaired ability to attach and spread on uncoated plastic”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Concentration-dependent SYK phosphorylation upon TREM2 antibody stimulation occurs in wild-type Parent line and is absent in TREM2 Ko line, confirming TREM2 specificity of the antibody.

    “We observed concentration-dependent SYK phosphorylation upon TREM2 antibody stimulation in the wild-type BIONi010-C (Parent) line, which was absent in the isogenic TREM2 Ko line (Fig. 1A), confirming TREM2 specificity of the antibody.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cell adhesion to fibronectin was not affected by SYK inhibition, but there was a significant increase in cell roundness in the Parent line.

    “Although cell adhesion to fibronectin was not affected by SYK inhibition, there was a significant increase in cell roundness in the Parent line”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    IP1 accumulation occurs in Parent cells upon TREM2 stimulation in a concentration-dependent manner, while TREM2 Ko cells fail to accumulate IP1.

    “We observed IP1 accumulation in Parent cells when stimulated with AF1828 in a concentration-dependent manner, while TREM2 Ko cells failed to accumulate IP1”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Fibronectin coating did not rescue the cell spreading phenotype of Ko cells, since cell area and roundness were not affected.

    “Even though adhesion was rescued, fibronectin coating did not rescue the cell spreading phenotype of the Ko cells, since cell area and roundness were not affected (Suppl. Figure 5).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    TREM2 ligation leads to phosphorylation of ERK1/2, which is not significantly different between Parent and PLCγ2 Ko.

    “TREM2 ligation lead to phosphorylation of ERK1/2, which was not significantly different between Parent and PLCγ2 Ko”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Adhesion and spreading of PLCγ2 Ko cells on vitronectin and laminin were impaired, while deficits in attachment were exacerbated by collagen type I and fibrinogen.

    “Adhesion and spreading of Ko cells on vitronectin and laminin were likewise impaired, while the deficits in attachment were exacerbated further by collagen type I and fibrinogen, with few cells being able to attach and weak spreading on these substrates (Fig. 5A, B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In PLCγ2 Ko cells, SYK phosphorylation was slightly delayed, with a significant increase of phospho-SYK observed from 2 h after plating.

    “In PLCγ2 Ko cells, SYK phosphorylation was slightly delayed, with a significant increase of phospho-SYK observed from 2 h after plating.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Parent cells show a robust Ca2+ response upon TREM2 stimulation, which is absent in TREM2 Ko cells.

    “Parent cells showed a robust Ca2+ response upon stimulation, which was absent in the TREM2 Ko cells (Fig. 1B, Suppl. Figure 3A).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The three PLCγ2 Ko clones showed lower surface expression of CD11b, while CD14 levels were clearly increased.

    “The three PLCγ2 Ko clones however showed lower surface expression of CD11b, while CD14 levels were clearly increased”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Parent cells were able to attach and spread on all coatings tested, with a slightly lower degree of adhesion to collagen type I and fibrinogen.

    “Parent cells were able to attach and spread on all coatings tested, with a slightly lower degree of adhesion to collagen type I and fibrinogen.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Fibronectin reversed the adhesion phenotype of PLCγ2 Ko cells, demonstrating similar degree of cell adhesion as Parent iPSC-macrophages.

    “An exception was fibronectin, which reversed the adhesion phenotype of PLCγ2 Ko cells, demonstrating similar degree of cell adhesion as the Parent iPSC-macrophages.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Adhesion to uncoated surface caused an increase in phospho-ERK1/2 after 45 min in Parent cells, which further increased after 2 h of attachment.

    “Adhesion to uncoated surface caused an increase in phospho-ERK1/2 after 45 min in Parent cells, which further increased after 2 h of attachment”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In PLCγ2 Ko cells, deficits in cell adhesion were further exacerbated by the SYK inhibitor, except adherence to fibrinogen, which was nearly prevented at baseline and could not be further reduced.

    “In PLCγ2 Ko cells the deficits in cell adhesion were further exacerbated in the presence of the SYK inhibitor, apart from adherence to fibrinogen, which was nearly prevented at baseline and could not be further reduced.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Challenging iPSC-derived macrophages with E.coli LPS induced secretion of TNFα and IL-6, but did not reveal differences in release in PLCγ2-deficient cells.

    “Challenging the iPSC-derived macrophages with E.coli LPS induced the secretion of TNFα and IL-6, but did not reveal any differences in release of those cytokines in PLCγ2-deficient cells (Fig. 4E).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisereasoning

    Many late-onset Alzheimer's disease susceptibility genes are predominantly expressed in myeloid cells such as microglia, emphasizing the role of the innate immune response in AD pathogenesis.

    “Many of these genes are predominantly expressed in myeloid cells such as microglia, the brain’s resident immune cells, emphasizing the role of the innate immune response in AD pathogenesis.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    PLCγ2 is a key component of intracellular signal transduction networks and induces Ca2+ signals downstream of many myeloid cell surface receptors, including TREM2.

    “PLCγ2 is a key component of intracellular signal transduction networks and induces Ca2+ signals downstream of many myeloid cell surface receptors, including TREM2.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    PLCγ2 is key in enabling divergent cellular functions and might be a promising target to increase beneficial microglial functions.

    “Thus, PLCγ2 is key in enabling divergent cellular functions and might be a promising target to increase beneficial microglial functions.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    PLCγ2 hydrolyses PIP2 to IP3 and DAG, leading to Ca2+ flux and PKC activation.

    “It hydrolyses the membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) to the secondary messengers inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 binds to ligand-gated ion channels present in the endoplasmic reticulum, increasing intracellular Ca2+ levels. DAG remains bound to the membrane and activates protein kinase C (PKC)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Baseline expression of several macrophage surface markers and cell morphology are distinctly altered in PLCγ2 Ko cells, pointing to fundamental differences in cells differentiated in the absence of PLCγ2 that could lead to altered functional effects.

    “The finding that baseline expression of several macrophage surface markers as well as cell morphology are distinctly altered in PLCγ2 Ko cells points to fundamental differences in cells differentiated in the absence of PLCγ2 that could lead to altered functional effects observed in the Ko lines.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Initial adhesion to fibronectin is facilitated by PLCγ2-independent mechanisms, while spreading on fibronectin is dependent on PLCγ2.

    “This suggests that initial adhesion to fibronectin is facilitated by PLCγ2-independent mechanisms, while spreading on fibronectin is dependent on PLCγ2.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Integrin-mediated activation of monocytes requires SYK.

    “It is known that integrin-mediated activation of monocytes requires SYK35”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Vines, C. M. et al. Inhibition of β2 integrin receptor and Syk kinase signaling in monocytes by the Src family kinase Fgr. Immunity 15, 507–519 (2001). source

  • Classified as probably not a substantial claim.

    Premisecitation

    Macrophage adhesion and spreading is regulated by several integrin receptors including β1, β2 and β3 integrins, which transduce signals to regulate actin cytoskeleton rearrangement, cell movement, and anchorage-dependent functions.

    “Macrophage adhesion and spreading is regulated by several integrin receptors including β1, β2 and β3 integrins, which transduce signals inside the cell to regulate rearrangement of the actin cytoskeleton, cell movement, and to integrate these signals with those of other transmembrane receptors to coordinate anchorage-dependent cellular functions34.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [34] Berton, G. & Lowell, C. A. Integrin signalling in neutrophils and macrophages. Cell. Signal. 11, 621–635 (1999). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    Differences in basal cell activation in the absence of PLCγ2 may be indicated by altered CD11b and CD14 expression.

    “possibly indicating differences in basal cell activation in the absence of PLCγ2.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    A lower abundance of TREM2 on the cell surface could account for changes in cell signalling and phenotype in PLCγ2 Ko cells.

    “This finding has to be kept in mind as a lower abundance of TREM2 on the cell surface could account for changes in cell signalling and phenotype.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    These data illustrate severe deficits in cell attachment and spreading of PLCγ2 Ko iPSC-macrophages with respect to several ECM molecules, indicating disturbances in a number of integrin receptor systems.

    “These data illustrate the severe deficits in cell attachment and spreading of the PLCγ2 Ko iPSC-macrophages with respect to several ECM molecules, indicating disturbances in a number of integrin receptor systems.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Three PLCγ2 Ko clones showed no major genetic alterations determined by Illumina SNP microarray analysis and were validated for absence of PLCγ2 protein by Western blotting.

    “Three Ko clones were selected that showed no major genetic alterations determined by Illumina SNP microarray analysis (Suppl. Figure 1) and were validated for the absence of PLCγ2 protein by Western blotting (Suppl. Figure 2A).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    ERK phosphorylation induced upon adhesion requires both the CD18 integrin chain and SYK.

    “Another indicator of integrin-induced macrophage activation that has been previously described is the analysis of ERK phosphorylation induced upon adhesion, which requires both the CD18 integrin chain and SYK32.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] Abram, C. L., Hu, Y., Lanier, L. L. & Lowell, C. A. Integrin signaling in neutrophils and macrophages uses adaptors containing immunoreceptor tyrosine-based activation motifs. 7, 1326–1333 (2006).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationown data

    The additional effect of the SYK inhibitor suggests upstream regulation of PLCγ2 by SYK and potentially partial compensation of PLCγ2 function by other mechanisms.

    “The additional effect of the SYK inhibitor suggests upstream regulation of PLCγ2 by SYK, and potentially a partial compensation of PLCγ2 function by other mechanisms.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Inositol signalling downstream of TREM2 depends on PLCγ2, indicating lack of a role for constitutive PLCγ1.

    “confirming the dependency of inositol signalling downstream of TREM2 on PLCγ2 and indicating the lack of a role for the constitutive PLCγ1.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Parent and PLCγ2 Ko lines showed similar amounts of PLCG1 gene expression, excluding the possibility that PLCγ1 is dysregulated to compensate for the absence of PLCγ2.

    “Parent and PLCγ2 Ko lines showed similar amounts of PLCG1 gene expression, as determined by RNAscope analysis, excluding the possibility that PLCγ1 is dysregulated to compensate for the absence of PLCγ2 (Suppl. Figure 2B).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Migration assay data were normalised to the average % migration for the entire plate to control for age-dependent differences in cell speed.

    “Treatments were performed in duplicate and duplicate wells were averaged, then normalised to the average % migration for the entire plate, to control for age-dependent differences in cell speed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PLCγ2 is directly involved in signalling pathways downstream of integrin receptors.

    “However, previous report have demonstrated a direct involvement of PLCγ2 in signalling pathways downstream of integrin receptors.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A role of PLCγ2 has been shown during B cell migration, where it was involved in chemokine-induced migration downstream of Btk.

    “A role of PLCγ2 has also been shown during B cell migration, where it was involved in chemokine-induced migration downstream of Btk53.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [53] De Gorter, D. J. J. et al. Article Bruton’s Tyrosine Kinase and Phospholipase Cg2 Mediate Chemokine-Controlled B Cell Migration and Homing. Immunity 26, 93–104 (2007). source

  • May combine two claims.

    Interpretationown data

    PLCγ2 is vital for regulation of several macrophage functions, including survival, phagocytosis, cell adhesion and migration.

    “PLCγ2 proved to be vital for the regulation of several macrophage functions, e.g. promoting survival, phagocytosis, cell adhesion and migration.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Deletion of PLCγ2 impaired cell adhesion to several ECM molecules, cell spreading, and migration, and these deficits corresponded with reduced expression of several integrin receptor subunits.

    “We observed that deletion of PLCγ2 impaired cell adhesion to several ECM molecules, and furthermore impaired cell spreading and migration, and that those deficits corresponded with reduced expression of several integrin receptor subunits.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    PLCγ2 Ko causes impairment in cell motility and migration in addition to adhesion deficits.

    “We conclude that in addition to deficits in cell adhesion, PLCγ2 Ko also causes an impairment in cell motility and migration.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Cell-substrate adhesions affect migration speed, with low or high adhesive strength slowing down migration, while intermediate adhesive strength enables optimal migration.

    “Cell-substrate adhesions affect migration speed, with low or high adhesive strength slowing down migration, while intermediate adhesive strength enables optimal migration47.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] Lauffenburger, D. A. & Horwitz, A. F. Cell Migration: review a physically integrated molecular process. Cell 84, 359–369 (1996). source

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    As an integral component of signalling pathways downstream of several immune receptors, including TREM2, loss of function in PLCγ2 affects a variety of cellular processes.

    “As an integral component of signalling pathways downstream of several immune receptors, including TREM2, a loss of function in PLCγ2 affects a variety of cellular processes.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Large-scale SNP quality-controlled batches were frozen at p15-25 and used within a minimal number of passages post-thaw to ensure consistency.

    “Large-scale SNP quality-controlled batches were frozen at p15–25 and used for experiments within a minimal number of passages post-thaw to ensure consistency.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    PLCγ2 deficiency resulted in pronounced changes in expression of macrophage receptors like several integrin subunits and TREM2, which could provide the molecular basis for observed functional effects or contribute to severity of phenotypic deficits.

    “PLCγ2 deficiency resulted in pronounced changes in expression of macrophage receptors like several integrin subunits and TREM2, which could provide the molecular basis for the observed functional effects, or at least contribute to the severity of the phenotypic deficits.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    The link between TREM2 and PLCγ2 in human microglia has been established, placing PLCγ2 downstream of TREM2 signalling and suggesting it as a key node to regulate TREM2 functions and inflammatory signalling via TLRs.

    “Recently, the link between TREM2 and PLCγ2 in human microglia has been established, placing PLCγ2 downstream of TREM2 signalling, and suggesting it as a key node to regulate TREM2 functions but also inflammatory signalling via TLRs26.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [26] Andreone, B. J. et al. Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat. Neurosci. 23, 927–938 (2020). source

  • May combine two claims.

    Interpretationown data

    PLCγ2 deficiency causes profound disturbances in several integrin receptor systems, providing an explanation for pronounced adhesion deficits to several ECM molecules.

    “Overall, this demonstrates profound disturbances in several integrin receptor systems in the absence of PLCγ2, which provides an explanation for the pronounced adhesion deficits to several ECM molecules we observed.”
    Quote in the paperSubstantial claim
64 of 64

  • The paper relies on this without support.

    The ability to form proper cell adhesion is necessary to enable motility and directed cell movements.

    “The ability to form proper cell adhesion is necessary to enable motility and directed cell movements.”

  • The paper relies on this without support.

    Phagocytosis of cortical synaptosomes and dead cells is initiated by detection of phosphatidylserine on their surface, a process that is at least partially mediated by TREM2.

    “Phagocytosis of cortical synaptosomes and dead cells is initiated by detection of phosphatidylserine on their surface, a process that is at least partially mediated by TREM2.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The TREM2-PLCγ2 signaling axis has been proposed to regulate phagocytosis, secretion of cytokines and chemokines, cell survival and proliferation in microglia.

    “The TREM2-PLCγ2 signaling axis has been proposed to regulate phagocytosis, secretion of cytokines and chemokines, cell survival and proliferation in microglia [17, 36, 37].”

    From PLCγ2 deficiency compromises systemic immune tolerance and erodes myelin homeostasis while enhancing oxidative metabolism in the mouse brain (2026) · cites this paper as [37]

    The Introduction and Discussion link TREM2–PLCγ2 signalling to phagocytosis and cell survival in microglia-related models. The Results and Discussion discuss cytokine secretion in connection with PLCγ2 and other inflammatory pathways, but do not establish it as a TREM2–PLCγ2 function; the supplied copy likewise does not link this axis to chemokine secretion or proliferation. Page numbers were not provided. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • Splenomegaly in this context reflects accumulation of myeloid cells with defective migration due to loss of Plcg2, rather than generalized lymphoid expansion.

    “supporting the idea that splenomegaly in this context reflects accumulation of myeloid cells with defective migration due to loss of Plcg2 [37], rather than generalized lymphoid expansion.”

    From PLCγ2 deficiency compromises systemic immune tolerance and erodes myelin homeostasis while enhancing oxidative metabolism in the mouse brain (2026) · cites this paper as [37]

    The Results and Discussion report impaired migration in PLCγ2-deficient human iPSC-derived macrophages. They do not examine splenomegaly, show that myeloid cells accumulate in the spleen, or compare that explanation with generalized lymphoid expansion. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • PLCG2 deficiency phenocopies the deficits in phagocytosis and immune reactivity to stimuli resulting from TREM2 deficiency in vitro.

    “these findings agree with previous research that reported that PLCG2 deficiency phenocopies the deficits in phagocytosis and immune reactivity to stimuli resulting from TREM2 deficiency in vitro. 16 , 43”

    From PLCG2 modulates TREM2 expression and signaling in response to Alzheimer's disease pathology (2025) · cites this paper as [43]

    The Discussion (page unavailable) explicitly says PLCγ2-deficient macrophages, like TREM2-knockout macrophages, showed reduced phagocytosis. The Results (page unavailable) also show impaired calcium signalling after TREM2 stimulation. But the broader claim of deficient immune reactivity to stimuli is not supported: LPS-induced TNFα and IL-6 secretion was unaffected by PLCγ2 deficiency. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • PLCG2 knockout iPSC-derived human macrophages exhibit decreased TREM2 and sTREM2.

    “Obst et al. found that PLCG2 knockout iPSC‐derived human macrophages exhibit decreased TREM2 and sTREM2”

    From Alzheimer's disease–associated PLCG2 variants alter microglial state and function in human induced pluripotent stem cell–derived microglia‐like cells (2025) · cites this paper as [28]

  • In microglia, PLCγ2 activity is downstream of TREM2 and Fc receptors, regulating inflammatory processes, migration, and endocytosis.

    “In microglia PLCγ2 activity has been documented to be downstream of TREM2 (19) and Fc receptors (15), regulating inflammatory processes, migration, and endocytosis (13, 16, 25, 33, 34).”

    From Multi-omics analyses reveal novel effects of PLCγ2 deficiency in the mouse brain (2023) · cites this paper as [25]

Cites

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Related

Authors
Obst, J., Hall-Roberts, H. L., Smith, T. B., Kreuzer, M., Magno, L., Di Daniel, E., Davis, J. B., & Mead, E.
Affiliations
  • University of Oxford (GB)
  • Alzheimer’s Research UK (GB)
Corresponding author
Obst, Juliane
ORCID
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2021-10-06
Volume
11
Issue
1
Pages
19842-19842
ISSN
2045-2322 (ISSN-L)
DOI
10.1038/s41598-021-96144-7
PMC
PMC8494732
OpenAlex
W3201774078
Semantic Scholar
5fced8f40d582e32aafcf1f93b5fad03bcb2d742
Cited by
36
References
61
Citations by year
2026: 8 · 2025: 12 · 2024: 6 · 2023: 5 · 2022: 4 · 2021: 1
FWCI
1.31
Type
journal article
Language
en
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • ORCA Online Research @Cardiff (Cardiff University) (acceptedVersion)
  • Europe PMC (PubMed Central) (submittedVersion, other-oa)
  • PubMed Central (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • UCL Discovery (University College London) (submittedVersion)
Funders
  • Alzheimer’s Research UK (ARUK-2020DDI-OX)
  • Cancer Research UK
  • Alzheimer's Research UK Drug Discovery Institute (520909)
Topics
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Life Sciences › Immunology and Microbiology › Immunology › Phagocytosis and Immune Regulation
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
Keywords
PLCγ2, TREM2, microglia, iPSC-derived macrophages, calcium signaling, integrin-mediated adhesion, macrophage migration, phagocytosis, microglial function, Alzheimer's disease, TNF-α, interleukin-6
MeSH terms
Calcium, Cell Adhesion, Cell Movement, Extracellular Matrix, Humans, Macrophages, Membrane Glycoproteins, Phagocytosis, Receptors, Immunologic, Signal Transduction, Biomarkers, Integrins, Cytokines, Inflammation Mediators, Phospholipase C gamma, Gene Knockdown Techniques, Induced Pluripotent Stem Cells

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-18.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-18.

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