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Cited by 8Neuroinflammation and Neurodegeneration MechanismsAlzheimer's disease research and treatmentsInflammasome and immune disorders

Alzheimer's disease–associated PLCG2 variants alter microglial state and function in human induced pluripotent stem cell–derived microglia‐like cells

Open access
Bedford, Logan M., Tutrow, Kaylee D., Hooper, Karly, Messenger, Evan J., Hernandez, Melody, Lamb, Bruce T., Meyer, Jason S., Richardson, Timothy I. +1 more·2025·Alzheimer's & Dementia
DOI 10.1002/alz.70772PMC PMC12510136
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Abstract

INTRODUCTION: Variants of phospholipase C gamma 2 (PLCG2), a key microglial immune signaling protein, are genetically linked to Alzheimer's disease (AD) risk. Understanding how PLCG2 variants alter microglial function is critical for identifying mechanisms that drive neurodegeneration or resiliency in AD. METHODS: Induced pluripotent stem cell (iPSC) –derived microglia carrying the protective PLCG2 P522R or risk‐conferring PLCG2 M28L variants, or loss of PLCG2, were generated to ascertain the impact on microglial transcriptome and function. RESULTS: Protective PLCG2 P522R microglia showed significant transcriptomic similarity to isogenic controls. In contrast, risk‐conferring PLCG2 M28L microglia shared similarities with PLCG2 KO microglia, with functionally reduced TREM2 expression, blunted inflammatory responses, and increased proliferation and cell death. Uniquely, PLCG2 P522R microglia showed elevated cytokine secretion after lipopolysaccharide (LPS) stimulation and were protected from apoptosis. DISCUSSION: These findings demonstrate that PLCG2 variants drive distinct microglia transcriptomes that influence microglial functional responses that could contribute to AD risk and protection. Targeting PLCG2‐mediated signaling may represent a powerful therapeutic strategy to modulate neuroinflammation. Highlights: The impact of Alzheimer's disease protective‐ and risk‐associated variants of phospholipase C gamma 2 (PLCG2) on the transcriptome and function of induced pluripotent stem cell (iPSC) –derived microglia was investigated. PLCG2 risk variant microglia exhibited a basal transcriptional profile similar to PLCG2‐deficient microglia but significantly different from isotype control and the transcriptionally similar PLCG2 protective variant microglia. PLCG2 risk variant and PLCG2‐deficient microglia show decreased levels of triggering receptor expressed on myeloid cells 2 (TREM2). The differential transcriptional pathways of protective and risk‐associated PLCG2 variant microglia functionally affect proliferation, apoptosis, and immune response. Protective PLCG2 microglia show resilience to apoptosis and increased cytokine/chemokine secretion upon exposure to lipopolysaccharide (LPS).

AI snapshot

Written from the paper’s full text.

TL;DR

Human iPSC-derived microglia-like cells carrying the AD-protective PLCG2P522R variant were transcriptionally similar to isogenic controls and showed resistance to apoptosis plus enhanced LPS-induced cytokine secretion. In contrast, the AD-risk PLCG2M28L variant resembled PLCG2-knockout microglia, with reduced TREM2, increased proliferation and cell death, and blunted inflammatory responses.

Key findings

  • PLCG2P522R microglia had the fewest unique differentially expressed genes versus WT (14 upregulated, 8 downregulated), while PLCG2M28L had the most (628 upregulated, 596 downregulated); PLCG2KO had 293 upregulated and 315 downregulated, with KO/M28L overlap of 256 upregulated and 385 downregulated genes.
  • PLCG2KO and PLCG2M28L microglia showed reduced PLCG2 and TREM2 protein by mean fluorescence intensity; TREM2 mRNA was significantly reduced in PLCG2KO, while P522R and M28L did not significantly alter PLCG2 or TREM2 mRNA levels.
  • PLCG2KO and PLCG2M28L microglia showed increased proliferation by EdU and Ki-67 versus WT and P522R. After 48 h cytokine deprivation, dead cells were ∼80% in KO and ∼87% in M28L versus ∼56% in WT and ∼47% in P522R; caspase 3/7 activation was 26% in KO, 6% in P522R, 20% in WT, and 16% in M28L.
  • After LPS stimulation, PLCG2P522R microglia increased secretion of CCL2, CCL4, CXCL1, CXCL9, IL-6, IL-8, IL-12p40, TNFα, and IL-1RA; PLCG2M28L showed decreased IL-3, IL-9, IL-17A, IL-27, and TGF-α relative to WT; PLCG2KO was similar to WT except for increased CCL2.

Methods

  • Isogenic iPSC lines on the ADRC5 background were used: WT, homozygous PLCG2P522R, homozygous PLCG2M28L generated by CRISPR/Cas9, and homozygous PLCG2KO. iPSCs were differentiated into hematopoietic progenitors and then microglia-like cells with IL-34, TGF-β1, and M-CSF for 25–28 days; assays used at least three independent differentiations.
  • Bulk RNA-sequencing was performed on four independent differentiations per genotype, mapped to hg38 with STAR, counted with featureCounts, and analyzed with edgeR; DEGs were FDR-adjusted p ≤ 0.05 and absolute fold change ≥ 1.2, with DAVID enrichment analysis.
  • Functional assays included immunocytochemistry, E. coli uptake, EdU and Ki-67 proliferation, live/dead and caspase 3/7 cell death assays, and LPS stimulation followed by multiplex ELISA. Statistics used non-parametric one-way or two-way ANOVA with Tukey’s or Sidak’s post hoc tests; p < 0.05 was significant.

Limitations

  • The paper states that reliance on a single isogenic iPSC-derived line may not capture phenotypes dependent on individual genetic variability, and that in vitro models have inherent limitations in recapitulating the in vivo microenvironment.
  • The paper states that the lack of priming stimuli for most experiments may have masked functional differences, particularly for PLCG2P522R microglia, and that future work should analyze phagocytic capacity for pathogenic particles and use more complex model systems.
  • Evident from the text: the study does not directly identify which signaling pathways cause the functional changes; the authors note that transcriptomic data suggest PLCG2P522R may act post-transcriptionally, but this remains to be tested.

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

Integrity signals

Registry

Crossref · 10.1002/alz.70772

Cites

55 of 55 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

49 of 59 cited sources checked · 27 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    In human microglia, PLCG2P522R decreases synaptosome uptake.

    “decreased synaptosome uptake, 27”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [27] Solomon S, Sampathkumar NK, Carre I, et al. Heterozygous expression of the Alzheimer's disease protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses. Cell Mol Life Sci. 2022; 79: 453. 35895133 PMC9329165 source
  • Premisecitation

    In human microglia, PLCG2P522R increases dextran uptake.

    “increased dextran 27 uptake”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [27] Solomon S, Sampathkumar NK, Carre I, et al. Heterozygous expression of the Alzheimer's disease protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses. Cell Mol Life Sci. 2022; 79: 453. 35895133 PMC9329165 source

      The Results section, “PLCγ2 P522R differential selectivity is driven by cargo size,” reports increased uptake of both 4-kD and 150-kD dextran in human iPSC-derived microglia heterozygous for P522R. The claim does not specify heterozygosity, and the passage does not show increased dextran uptake in homozygous cells. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
  • Premisecitation

    In human microglia, PLCG2P522R increases motility.

    “increased motility, 27”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [27] Solomon S, Sampathkumar NK, Carre I, et al. Heterozygous expression of the Alzheimer's disease protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses. Cell Mol Life Sci. 2022; 79: 453. 35895133 PMC9329165 source

      The Results section (‘Microglia with PLCγ2 P522R variant have higher Ca2+ signalling and increased motility’) reports greater motility in heterozygous P522R human iPSC-derived microglia than in wild-type cells. The claim omits that qualification: homozygous P522R cells did not show the same increase. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
  • Premisecitation

    In human microglia, PLCG2P522R increases amyloid beta (Aβ) uptake.

    “increased amyloid beta (Aβ) uptake, 27 , 30”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [27] Solomon S, Sampathkumar NK, Carre I, et al. Heterozygous expression of the Alzheimer's disease protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses. Cell Mol Life Sci. 2022; 79: 453. 35895133 PMC9329165 source
    • cites [30] Maguire E, Menzies GE, Phillips T, et al. PIP2 depletion and altered endocytosis caused by expression of Alzheimer's disease‐protective variant PLCγ2 R522. EMBO J. 2021‐07‐13; 40: e105603. 34254352 PMC8408593 source
  • Premisecitation

    In human microglia, PLCG2P522R increases enzymatic activity.

    “In human microglia, PLCG2P522R has been shown to increase enzymatic activity 30”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [30] Maguire E, Menzies GE, Phillips T, et al. PIP2 depletion and altered endocytosis caused by expression of Alzheimer's disease‐protective variant PLCγ2 R522. EMBO J. 2021‐07‐13; 40: e105603. 34254352 PMC8408593 source
  • Classified as probably not a substantial claim. 21
  • May combine two claims. 33
  • The quote only partly states this claim. 3

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

    Premisecitation

    Mutations in PLCG2 that constitutively activate the enzyme contribute to autoinflammatory disorders and resistance mechanisms in cancer treatment.

    “mutations in PLCG2 that constitutively activate the enzyme contribute to autoinflammatory disorders and resistance mechanisms in cancer treatment. 21 , 22 , 23”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [21] Zhou Q, Lee GS, Brady J, et al. A hypermorphic missense mutation in PLCG2, encoding phospholipase Cgamma2, causes a dominantly inherited autoinflammatory disease with immunodeficiency. Am J Hum Genet. 2012; 91: 713‐ 720. 23000145 PMC3484656 source
    • cites [22] Neves JF, Doffinger R, Barcena‐Morales G, et al. Frontiers | novel PLCG2 mutation in a patient with APLAID and cutis laxa. Front Immunol. 2018; 14: 2863. PMC6302768 30619256 source

      The Introduction (page not available) reports constitutive PLCγ2 activation in PLAID and links an activating PLCG2 mutation to the autoinflammatory disorder APLAID, but explicitly says the APLAID mutation is not constitutively active. The Case Report (page not available) describes an activating PLCG2 mutation associated with resistance to the cancer drug ibrutinib, without saying that mutation constitutively activates the enzyme. Thus the disease and treatment-resistance links are supported, but the constitutive-activation qualifier is not supported for both. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [23] Jackson JT, Mulazzani E, Nutt SL, Masters SL. The role of PLCgamma2 in immunological disorders, cancer, and neurodegeneration. J Biol Chem. 2021; 297: 100905. 34157287 PMC8318911 source

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

    Premisecitation

    PLCG2M28L decreases Aβ uptake in primary murine microglia.

    “it has been reported to decrease Aβ uptake in primary murine microglia. 19”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [19] Tsai AP, Dong C, Lin PB, et al. Genetic variants of phospholipase C‐gamma2 alter the phenotype and function of microglia and confer differential risk for Alzheimer's disease. Immunity. 2023; 56: 2121‐ 2136. 37659412 PMC10564391 source

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

    Premisecitation

    PLCG2P522R modulates phagocytosis, inflammatory responses, lipid profiles, and mitochondrial function in myeloid cells.

    “Several studies have examined the role of PLCG2P522R in myeloid cells and reported that this variant modulates phagocytosis, inflammatory responses, lipid profiles, and mitochondrial function. 11 , 19 , 24 , 25 , 26 , 27 , 28 , 29 , 30”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [11] Magno L, Lessard CB, Martins M, et al. Alzheimer's disease phospholipase C‐gamma‐2 (PLCG2) protective variant is a functional hypermorph. Alzheimers Res Ther. 2019; 11: 16. 30711010 PMC6359863 source

      The Results show that P522R weakly increases PLCγ2 enzyme activity, and the Discussion proposes that PLCγ2 activity in microglia might influence phagocytosis and immune responses. The paper does not establish that P522R modulates those myeloid-cell responses, and it does not report effects on lipid profiles or mitochondrial function. Page numbers are unavailable in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [19] Tsai AP, Dong C, Lin PB, et al. Genetic variants of phospholipase C‐gamma2 alter the phenotype and function of microglia and confer differential risk for Alzheimer's disease. Immunity. 2023; 56: 2121‐ 2136. 37659412 PMC10564391 source

      The Introduction (page unavailable) reports altered phagocytic activity, cytokine secretion, and cholesterol metabolism with PLCG2 P522R. The section on transcriptional programs in 5xFAD mice also links P522R to phagocytosis, inflammatory response, and lipid-metabolism pathways. Our copy does not support the attributed effect on mitochondrial function; its only mention of mitochondria concerns a sequencing-quality filter. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [24] Staley HA, Jernigan JE, Bolen ML, et al. Alzheimer's disease‐associated protective variant Plcg2‐P522R modulates peripheral macrophage function in a sex‐dimorphic manner. J Neuroinflammation. 2024; 21: 280. 39487477 PMC11529260 source

      The Results sections report that P522R changes phagocytosis and inflammatory cytokine secretion in mouse peritoneal macrophages, with effects that differ by sex. The Background mentions lipid metabolism as a function of PLCG2 generally, but does not establish that P522R changes lipid profiles; searches for lipid profiles and mitochondrial function found no supporting passage in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    Genetic studies have identified numerous AD risk variants in immune- and microglial-associated genes.

    “Genetic studies have identified numerous AD risk variants in immune‐ and microglial‐associated genes, highlighting the importance of microglia function in disease progression. 3 , 4 , 5 , 6 , 7”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [3] Bertram L, Tanzi RE. Genome‐wide association studies in Alzheimer's disease. Hum Mol Genet. 2009; 18: R137‐ 45. 19808789 PMC2758713 source
    • cites [4] Lambert JC, Ibrahim‐Verbaas CA, Harold D, et al. Meta‐analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease. Nat Genet. 2013; 45: 1452‐ 1458. 24162737 PMC3896259 source
    • cites [5] Karch CM, Goate AM. Alzheimer's disease risk genes and mechanisms of disease pathogenesis. Biol Psychiatry. 2015; 77: 43‐ 51. 24951455 PMC4234692 source

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

    Premisecitation

    PLCG2P522R is overrepresented among centenarians.

    “and is overrepresented among centenarians. 18”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [18] Tesi N, van der Lee S, Hulsman M, et al. Cognitively healthy centenarians are genetically protected against Alzheimer's disease. Alzheimers Dement. 2024; 20: 3864‐ 3875. 38634500 PMC11180929 source

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

    Study design and conductcitation

    PLCG2 antibody selection was validated by YCharOS.

    “PLCG2 antibody selection was validated by YCharOS. 34”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [34] Ruiz Moleon V, Fotouhi M, Alende C, et al. A guide to selecting high‐performing antibodies for PLC‐gamma‐2 for use in Western Blot, immunoprecipitation and immunofluorescence. F1000Res. 2024; 13: 77. 39429638 PMC11489847 source

      The Introduction and Results and discussion (pages not provided) describe testing eleven PLC-gamma-2 antibodies and identifying several that performed well under the study’s conditions. This supports using the characterization data to guide antibody selection, but the authors explicitly say they do not offer antibody recommendations; the paper does not establish that a particular selection was validated by YCharOS. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    PLCG2M28L modulates phagocytic capability and alters inflammatory responses.

    “PLCG2M28L, though less studied, has been shown to modulate phagocytic capability and alter inflammatory responses. 19 , 20”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [19] Tsai AP, Dong C, Lin PB, et al. Genetic variants of phospholipase C‐gamma2 alter the phenotype and function of microglia and confer differential risk for Alzheimer's disease. Immunity. 2023; 56: 2121‐ 2136. 37659412 PMC10564391 source
    • cites [20] Oblak AL, Kotredes KP, Pandey RS, et al. Plcg2(M28L) interacts with high fat/high sugar diet to accelerate Alzheimer's disease‐relevant phenotypes in mice. Front Aging Neurosci. 2022; 14: 886575. 35813947 PMC9263289 source

      The Results section reports altered brain and plasma cytokines in LOAD1.Plcg2M28L mice, supporting the inflammatory-response part of the claim. It also reports enrichment of phagocytosis-related gene pathways, but does not show that the variant changes phagocytic capability itself; the Introduction says the precise effects of M28L had not yet been elucidated. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

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

    Premisecitation

    IP3 triggers calcium release and DAG activates PKC and other effector proteins, influencing microglial processes such as migration, phagocytosis, cytokine secretion, and metabolic responses.

    “IP3 triggers calcium release from intracellular stores, while DAG activates protein kinase C (PKC) and other effector proteins, ultimately influencing microglial processes such as migration, phagocytosis, cytokine secretion, and metabolic responses. 13 , 16 , 17”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [13] Andreone BJ, Przybyla L, Llapashtica C, et al. Alzheimer's‐associated PLCgamma2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia. Nat Neurosci. 2020; 23: 927‐ 938. 32514138 source
    • cites [16] Chae JJ, Park YH, Park C, et al. Connecting two pathways through Ca 2+ signaling: nLRP3 inflammasome activation induced by a hypermorphic PLCG2 mutation. Arthritis Rheumatol. 2015; 67: 563‐ 567. 25418813 PMC4369162 source

      The Introduction (page unavailable) states that InsP3 releases calcium from ER stores and identifies DAG as another product of PLCγ2. The Discussion (page unavailable) says PLCγ2 signaling includes PKC, but does not specifically link DAG to PKC or address other effector proteins. The Results concern IL-1β secretion from human PBMCs, not migration, phagocytosis, cytokine secretion, or metabolic responses in microglia. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [17] Griner EM, Kazanietz MG, Griner EM, Kazanietz MG. Protein kinase C and other diacylglycerol effectors in cancer. Nat Rev Can. 2007; 7: 281‐ 294. 17384583 source

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

    Premisecitation

    THEM6 encodes thioesterase superfamily member six, which is involved in lipid metabolism and homeostasis.

    “THEM6 encodes thioesterase superfamily member six, which is involved in lipid metabolism and homeostasis. 44”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [44] Blomme A, Peter C, Mui E, et al. THEM6‐mediated reprogramming of lipid metabolism supports treatment resistance in prostate cancer. EMBO Mol Med. 2022; 14: e14764. 35014179 PMC8899912 source

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

    Premisecitation

    Prior studies have shown contradictory findings with respect to the role of PLCG2 in proliferation and apoptosis.

    “Prior studies have shown contradictory findings with respect to the role of PLCG2 in proliferation and apoptosis.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [49] Zhao C, Miao D, Tan D, et al. The PLCG2 inhibits tumor progression and mediates angiogenesis by VEGF signaling pathway in clear cell renal cell carcinoma. Front Biosci 2024; 29: 390. 39614428 source

      The Conclusions (section 5; page unavailable) report that PLCG2 inhibits proliferation in clear cell renal cell carcinoma, but they do not describe contradictory findings from prior studies. Searches for conflicting findings and apoptosis found no passage addressing either point; the Discussion (section 4; page unavailable) discusses differing roles of MAPK components, not contradictory findings about PLCG2. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
    • cites [50] Zhou X, Lin J, Shao Y, et al. Targeting PLCG2 suppresses tumor progression, orchestrates the tumor immune microenvironment and potentiates immune checkpoint blockade therapy for colorectal cancer. Int J Biol Sci. 2024; 20: 5548‐ 5575. 39494327 PMC11528457 source

      The Discussion (page unavailable) summarizes prior work on PLCG2 in several cancers but does not describe contradictory findings on proliferation or apoptosis. The Results report this paper’s own findings that PLCG2 promotes proliferation and inhibits apoptosis in colorectal cancer cells. Searches for conflicting or opposing prior findings found no passage addressing the claimed contradiction. (LLM, conf=0.72)

      Experimental — accuracy not yet measured
    • cites [51] Yang Y, Yang Y, Huang H, et al. PLCG2 can exist in eccDNA and contribute to the metastasis of non‐small cell lung cancer by regulating mitochondrial respiration. Cell Death Dis. 2023; 14: 257. 37031207 PMC10082821 source

      The Results section, “PLCG2 promoted the proliferation, migration, and invasion of H1299 cells” (page unavailable), says prior work implicated PLCG2 in proliferation and reports this paper’s own findings on proliferation and apoptosis. It does not describe contradictory findings from prior studies about either outcome. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Loss of TREM2 induces age-related myelin dysregulation.

    “Loss of TREM2 has been shown to induce age‐related myelin dysregulation, 48”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [48] McCray TJ, Bedford LM, Bissel SJ, et al. Trem2‐deficiency aggravates and accelerates age‐related myelin degeneration. Acta Neuropathol Comm. 2024; 12: 154. PMC11411802 39300502 source

  • May combine two claims.

    Premisecitation

    Prior studies show mild effects of the PLCG2P522R variant on the microglial transcriptome in vitro or in healthy mice, but a stronger effect in the presence of pathology.

    “This aligns with prior studies showing mild effects of the PLCG2P522R variant on the microglial transcriptome in vitro or in healthy mice, 27 , 29 but a stronger effect in the presence of pathology. 19 , 26 , 31”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [27] Solomon S, Sampathkumar NK, Carre I, et al. Heterozygous expression of the Alzheimer's disease protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses. Cell Mol Life Sci. 2022; 79: 453. 35895133 PMC9329165 source
    • cites [29] Takalo M, Wittrahm R, Wefers B, et al. The Alzheimer's disease‐associated protective Plcgamma2‐P522R variant promotes immune functions. Mol Neurodegener. 2020; 15: 52. 32917267 PMC7488484 source

      In Findings, the paper reports moderate changes in microglia-associated genes in six-month-old knock-in mice, supporting the cited point about mild effects in mice without AD pathology. But the expression analysis used whole-brain tissue, not an isolated microglial transcriptome. The stronger effect in the presence of pathology is attached to other citations in the citing sentence, and this paper says studies with AD-associated pathology are still needed. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [19] Tsai AP, Dong C, Lin PB, et al. Genetic variants of phospholipase C‐gamma2 alter the phenotype and function of microglia and confer differential risk for Alzheimer's disease. Immunity. 2023; 56: 2121‐ 2136. 37659412 PMC10564391 source

  • Classified as probably not a substantial claim.

    Premisecitation

    THEM6 has been shown to be a microglial Aβ response protein, with increased abundance in the presence of amyloid pathology.

    “THEM6 has been shown to be a microglial Aβ response protein, with increased abundance in the presence of amyloid pathology. 45”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [45] Sebastian Monasor L, Müller SA, Colombo AV, et al. Fibrillar Aβ triggers microglial proteome alterations and dysfunction in Alzheimer mouse models. eLife. 2020; 9: e54083. 32510331 PMC7279888 source

      The Results describe proteins whose abundance changes in plaque-associated microglia, and the Discussion describes a broader proteomic response to Aβ deposition. Neither identifies THEM6 or reports its abundance. Searches for “THEM6” and its expanded protein name found no supporting passage in our copy. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    PLCG2 protein expression is abundant in WT and P522R MGLs but significantly reduced in KO and M28L cells.

    “PLCG2 expression (green) is abundant in PLCG2WT and PLCG2P522R MGLs but significantly reduced in PLCG2KO and PLCG2M28L cells”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    TREM2 protein staining is strong in WT and P522R MGLs but reduced in KO and M28L cells.

    “PLCG2WT and PLCG2P522R MGLs exhibit strong fluorescent staining for TREM2 (red), whereas PLCG2KO and PLCG2M28L cells display reduced staining”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    KO and M28L samples displayed more pronounced shifts in gene expression relative to WT samples, while P522R MGLs were more closely related.

    “KO and M28L samples displayed more pronounced shifts in gene expression relative to WT samples, while P522R MGLs were more closely related.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    PLCG2M28L MGLs show increased proliferation and cell death.

    “increased proliferation and cell death”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • The quote only partly states this claim.

    Findingown data

    PLCG2KO MGLs exhibit a significant reduction in PLCG2 mRNA relative to WT cells.

    “PLCG2KO MGLs exhibit a significant reduction in PLCG2 relative to WT cells.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • The quote only partly states this claim.

    Findingown data

    MFI quantification confirms significant reductions in TREM2 in KO and M28L MGLs.

    “MFI quantification confirms significant reductions in TREM2 in PLCG2KO and PLCG2M28L MGLs”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    P522R and M28L PLCG2 variants do not significantly alter PLCG2 or TREM2 mRNA expression levels.

    “the P522R and M28L PLCG2 variants do not significantly alter PLCG2 or TREM2 expression levels.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    PC2 represents an additional 21% of the variance, with the M28L and KO groups clustering separately.

    “PC2 represents an additional 21% of the variance, with the M28L and KO groups clustering separately”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    The first principal component (PC1) accounts for 27% of the variance and clearly separates WT from the variant groups.

    “The first principal component (PC1) accounts for 27% of the variance, clearly separating WT from the variant groups.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

  • May combine two claims.

    Findingown data

    Pro-apoptotic genes FAS and MMP9 were upregulated in PLCG2M28L MGLs, whereas PLCG2WT cells exhibited lower expression of these genes.

    “Several pro‐apoptotic genes, such as FAS and MMP9, were upregulated in PLCG2M28L MGLs, whereas PLCG2WT cells exhibited lower expression of these genes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The immune-related gene signature of PLCG2P522R MGLs included the unique increase in expression of DAPK1 and the unique decrease in expression of CGAS.

    “Interestingly, respective to the other MGL lines, the immune‐related gene signature of PLCG2P522R MGLs included the unique increase in expression of DAPK1 and the unique decrease in expression of CGAS.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    PLCG2P522R MGLs showed resilience to apoptosis compared to PLCG2WT MGLs, with no difference in proliferation.

    “Conversely, PLCG2P522R MGLs showed resilience to apoptosis compared to PLCG2WT MGLs, with no difference in proliferation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Compared to PLCG2WT MGLs, PLCG2P522R MGLs elicited significant increases in secretion of chemokines (CCL2, CCL4, CXCL1, and CXCL9) and pro-inflammatory cytokines (IL-6, IL-8, IL-12p40, TNFα); secretion of the regulatory cytokine IL-1RA is also increased.

    “Compared to PLCG2WT MGLs, PLCG2P522R MGLs elicited significant increases in secretion of chemokines (CCL2, CCL4, CXCL1, and CXCL9) and pro‐inflammatory cytokines (IL‐6, IL‐8, IL‐12p40, TNFα); however, secretion of the regulatory cytokine IL‐1RA is also increased.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Over 48 h of cytokine starvation, PLCG2KO MGLs displayed a substantial increase in caspase activation (26%), whereas PLCG2P522R cells showed decreased apoptosis relative to PLCG2WT MGLs (6%).

    “Over 48 h of cytokine starvation, PLCG2KO MGLs displayed a substantial increase in caspase activation (red signal) (26%), whereas PLCG2P522R cells showed decreased apoptosis relative to PLCG2WT MGLs (6%) (Figure 5D‐E).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    PLCG2KO and PLCG2M28L MGLs exhibited significant reductions in both PLCG2 and TREM2 levels, whereas PLCG2WT and PLCG2P522R MGLs maintained robust levels.

    “Transcriptomic and protein analyses showed that PLCG2KO and PLCG2M28L MGLs exhibited significant reductions in both PLCG2 and TREM2 levels, whereas PLCG2WT and PLCG2P522R MGLs maintained robust levels.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    PLCG2KO and PLCG2M28L MGLs show increased proliferation compared to PLCG2WT MGLs, while proliferation in PLCG2P522R MGLs is similar to PLCG2WT cells.

    “Taken together, these results indicate that PLCG2KO and PLCG2M28L MGLs show increased proliferation compared to PLCG2WT MGLs, while proliferation in PLCG2P522R MGLs is similar to PLCG2WT cells.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    We identified genes that were uniquely differentially expressed in PLCG2P522R MGLs.

    “we identified genes that were uniquely differentially expressed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Ki-67 quantification showed low levels of proliferation in PLCG2WT and PLCG2P522R MGLs but a significant increase in the percentage of proliferating cells in PLCG2KO MGLs compared to WT cells.

    “Quantification of Ki‐67+ cells also showed low levels of proliferation in PLCG2WT and PLCG2P522R MGLs but a significant increase in the percentage of proliferating cells in PLCG2KO MGLs compared to WT cells.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The cytokine secretome of PLCG2M28L MGLs shared similarities to PLCG2WT MGLs but showed a decrease in the secretion of some cytokines (IL-3, IL-9, IL-17A, IL-27, and TGF-α).

    “Importantly, the cytokine secretome of PLCG2M28L MGLs shared similarities to PLCG2WT MGLs but showed a decrease in the secretion of some cytokines (IL‐3, IL‐9, IL‐17A, IL‐27, and TGF‐α).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductreasoning

    All iPSC lines were generated from the ADRC5 parental line, providing a well-characterized isogenic control background that eliminates potential differences in individual genomes.

    “All iPSC lines were generated from the ADRC5 parental line, providing a well‐characterized isogenic control background, thus eliminating potential differences in individual genomes.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    PLCG2 mediates the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG).

    “PLCG2 associates with the membrane and mediates the hydrolysis of phosphatidylinositol 4, 5‐bisphosphate (PIP2) into two important second messengers: inositol 1, 4, 5‐trisphosphate (IP3) and diacylglycerol (DAG). 14 , 15”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [14] Bunney TD, Katan M. PLC regulation: emerging pictures for molecular mechanisms. Trends Biochem Sci. 2011; 36: 88‐ 96. 20870410 source
    • cites [15] Bunney TD, Katan M, Bunney TD, Katan M. Phosphoinositide signalling in cancer: beyond PI3K and PTEN. Nat Rev Can. 2010; 10: 342‐ 352. 20414202 source

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Targeting PLCG2-mediated signaling may represent a powerful therapeutic strategy to modulate neuroinflammation.

    “Targeting PLCG2‐mediated signaling may represent a powerful therapeutic strategy to modulate neuroinflammation.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.
    • Rests on an assumption: The in vitro functional changes observed in MGLs (proliferation, apoptosis, cytokine secretion) reflect mechanisms that contribute to AD risk or protection in the human brain.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    All assays were conducted with at least three independent differentiations.

    “All assays were conducted with at least three independent differentiations.”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    RNA samples with a RIN > 8 were used for library construction.

    “RNA samples with a RIN > 8 were used for library construction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    PLCG2 variants drive distinct microglia transcriptomes that influence microglial functional responses that could contribute to AD risk and protection.

    “These findings demonstrate that PLCG2 variants drive distinct microglia transcriptomes that influence microglial functional responses that could contribute to AD risk and protection.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.
    • Rests on an assumption: The in vitro functional changes observed in MGLs (proliferation, apoptosis, cytokine secretion) reflect mechanisms that contribute to AD risk or protection in the human brain.

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

    Study design and conductnone given

    Each iPSC line underwent karyotyping and routine mycoplasma screening.

    “Each line underwent karyotyping and routine mycoplasma screening using a commercially available kit”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The protective P522R variant sensitizes MGLs to LPS stimulation, resulting in an enhanced inflammatory response.

    “Taken together, these results show that the protective P522R variant sensitizes MGLs to LPS stimulation, resulting in an enhanced inflammatory response”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    PLCG2M28L is post-translationally degraded or the mRNA is not translated effectively.

    “This suggests that PLCG2M28L is post‐translationally degraded or that the mRNA is not translated effectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Absence of PLCG2 promotes increased sensitivity to apoptosis under cytokine starvation, likely due to transcriptional upregulation of pro-apoptotic genes.

    “Together, these results indicate that absence of PLCG2 promotes increased sensitivity to apoptosis under cytokine starvation, likely due to transcriptional upregulation of pro‐apoptotic genes.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The mild effect of PLCG2P522R on basal human MGL gene expression suggests additional stimuli or more complex experimental systems may be required to fully understand its transcriptional impact.

    “the mild effect of PLCG2P522R on basal human MGL gene expression suggests additional stimuli or more complex experimental systems may be required to fully understand its transcriptional impact.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Murine microglia carrying PLCG2P522R exhibited numerous effects on microglial gene expression in the context of amyloid pathology.

    “Since we previously showed that murine microglia carrying PLCG2P522R exhibited numerous effects on microglial gene expression in the context of amyloid pathology”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    Statistical analyses used non-parametric one-way or two-way ANOVA with Tukey's or Sidak's post hoc test, with p < 0.05 considered significant.

    “Analyses were performed using a non‐parametric one‐way or two‐way analysis of variance (ANOVA) with Tukey's or Sidak's post hoc test. p < 0.05 was considered significant.”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    The lack of priming stimuli conditions for most of the experiments in this study may have masked functional differences, particularly for microglia bearing PLCG2P522R.

    “The lack of priming stimuli conditions for most of the experiments in this study may have masked functional differences, particularly for microglia bearing PLCG2P522R, which might require stimuli to reveal its full effects.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Loss-of-function genotypes PLCG2KO and PLCG2M28L result in profound microglial dysfunction, affecting proliferation, apoptosis, and immune response.

    “Loss‐of‐function genotypes, PLCG2KO and PLCG2M28L result in profound microglial dysfunction, affecting proliferation, apoptosis, and immune response—all of which can contribute to AD pathogenesis.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The effects of PLCG2 variants observed in this in vitro model reflect their effects on microglia in the human AD brain.

  • May combine two claims.

    Interpretationreasoning

    PLCG2 is essential for proper microglial response to PAMPs, and its loss leads to an attenuated inflammatory response.

    “Overall, these results suggest that PLCG2 is essential for proper microglial response to PAMPs, and its loss leads to an attenuated inflammatory response.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Study design and conductnone given

    In vitro models have inherent limitations in recapitulating the in vivo microenvironment.

    “Additionally, in vitro models have inherent limitations in recapitulating the in vivo microenvironment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    PLCG2 is a key regulator of microglial function, with broad implications for AD and neurodegeneration.

    “Taken together, these findings establish PLCG2 as a key regulator of microglial function, with broad implications for AD and neurodegeneration.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    This study provides critical insights into how PLCG2 variants shape microglial biology, influencing their transcriptional profiles, proliferation, survival, and immune competence.

    “In conclusion, this study provides critical insights into how PLCG2 variants shape microglial biology, influencing their transcriptional profiles, proliferation, survival, and immune competence.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Human iPSC-derived microglia-like cells recapitulate key functional properties of human microglia in vivo.
51 of 51

  • The paper relies on this without support.

    iPSC-derived microglia-like cells (MGLs) faithfully model human microglia in vivo.

    “iPSC‐derived human MGLs expressing PLCG2 variants display hallmark characteristics of microglia”
    “This study aims to address these gaps in knowledge by using iPSC‐derived microglial models to reveal the impact of PLCG2 variants on transcriptional profiles”

  • The paper relies on this without support.

    The in vitro functional changes observed in MGLs (proliferation, apoptosis, cytokine secretion) reflect mechanisms that contribute to AD risk or protection in the human brain.

    “These findings demonstrate that PLCG2 variants drive distinct microglia transcriptomes that influence microglial functional responses that could contribute to AD risk and protection.”

  • The paper relies on this without support.

    Human iPSC-derived microglia-like cells recapitulate key functional properties of human microglia in vivo.

    “by using human MGLs, we have established a valuable experimental platform for future therapeutic research.”

  • The paper relies on this without support.

    The effects of PLCG2 variants observed in this in vitro model reflect their effects on microglia in the human AD brain.

    “The dysregulation observed in PLCG2‐deficient and loss‐of‐function MGLs has profound implications for AD”

  • The paper relies on this without support.

    Cytokine starvation is a valid model of stress-induced cell death relevant to AD.

    “Cell death was induced by cytokine starvation (absence of M‐CSF, TGF‐β1, and IL‐34) followed by a live/dead assay”

  • The paper relies on this without support.

    LPS stimulation is a valid model of PAMP/DAMP-induced microglial activation relevant to AD.

    “we performed a LPS stimulation assay”

  • The paper relies on this without support.

    The single isogenic iPSC line's genetic background does not confound the effects attributed to PLCG2 variants.

    “this study relied on a single isogenic iPSC‐derived line, which may not fully capture phenotypes dependent upon individual genetic variability.”

  • The paper relies on this without support.

    The PLCG2 KO and M28L variants are loss-of-function and P522R is protective in human microglia.

    “the protective P522R variant sensitizes MGLs to LPS stimulation”

  • The paper relies on this without support.

    The transcriptomic changes observed in bulk RNAseq reflect changes in microglial state and function.

    “The transcriptomic differences between PLCG2 variant MGLs indicated that microglial functions such as proliferation, apoptosis, and inflammatory response might be affected.”
9 of 9

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • LPS timing differs between methods and figure caption

    Major

    The methods say LPS was added when the cells were switched to TGF-β-free media. The Figure 6 caption instead describes 24 hours without TGF-β before LPS was added.

  • Conflicting numbers of genes in the PLCG2-correlation heatmap

    Minor

    The results describe a heatmap of the top 50 genes correlated with PLCG2 expression, while the caption for the same figure says it contains the top 75 genes.

2 of 2

Cites

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Authors
Bedford, L. M., Tutrow, K. D., Hooper, K., Messenger, E. J., Hernandez, M., Lamb, B. T., Meyer, J. S., Richardson, T. I., & Bissel, S. J.
Affiliations
  • Indiana University Indianapolis (US)
  • Indiana University School of Medicine
Corresponding author
Bissel, Stephanie J.
ORCID
Venue
Alzheimer's & Dementia
Publisher
Wiley
Published
2025-10
Volume
21
Issue
10
Pages
e70772-e70772
ISSN
  • 1552-5260 (ISSN-L)
  • 1552-5279
DOI
10.1002/alz.70772
PMC
PMC12510136
OpenAlex
W4415010678
Semantic Scholar
c2424175cbdfdf1fd8895003f34a66c9a7e0033c
Cited by
8
References
54
Citations by year
2026: 8
FWCI
2.36
Type
journal article
Language
en
Open access
Licence
Locations
  • Alzheimer s & Dementia (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (submittedVersion, cc-by-nc)
  • PubMed Central (submittedVersion, cc-by-nc)
  • IUScholarWorks (Indiana University) (submittedVersion, cc-by-nc)
Funders
National Institute on Aging (R01AG074566, U54AG065181, F31AG089990, F30AG084304, T32AG071444)
Topics
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Inflammasome and immune disorders
Keywords
Alzheimer's disease, PLCγ2
MeSH terms
Alzheimer Disease, Humans, Membrane Glycoproteins, Receptors, Immunologic, Microglia, Phospholipase C gamma, Induced Pluripotent Stem Cells, Transcriptome

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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