Cited by 698Multiple Sclerosis Research StudiesNeuroinflammation and Neurodegeneration MechanismsInflammasome and immune disorders

Loss of ‘homeostatic’ microglia and patterns of their activation in active multiple sclerosis

Open access
Zrzavy, Tobias, Hametner, Simon, Wimmer, Isabella, Butovsky, Oleg, Weiner, Howard L., Lassmann, Hans·2017·Brain

Abstract

Microglia and macrophages accumulate at the sites of active demyelination and neurodegeneration in the multiple sclerosis brain and are thought to play a central role in the disease process. We used recently described markers to characterize the origin and functional states of microglia/macrophages in acute, relapsing and progressive multiple sclerosis. We found microglia activation in normal white matter of controls and that the degree of activation increased with age. This microglia activation was more pronounced in the normal-appearing white matter of patients in comparison to controls and increased with disease duration. In contrast to controls, the normal-appearing white matter of patients with multiple sclerosis showed a significant reduction of P2RY12, a marker expressed in homeostatic microglia in rodents, which was completely lost in active and slowly expanding lesions. Early stages of demyelination and neurodegeneration in active lesions contained microglia with a pro-inflammatory phenotype, which expressed molecules involved in phagocytosis, oxidative injury, antigen presentation and T cell co-stimulation. In later stages, the microglia and macrophages in active lesions changed to a phenotype that was intermediate between pro- and anti-inflammatory activation. In inactive lesions, the density of microglia/macrophages was significantly reduced and microglia in part converted to a P2RY12+ phenotype. Analysis of TMEM119, which is expressed on microglia but not on recruited macrophages, demonstrated that on average 45% of the macrophage-like cells in active lesions were derived from the resident microglia pool. Our study demonstrates the loss of the homeostatic microglial signature in active multiple sclerosis with restoration associated with disease inactivity.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1093/brain/awx113

Cites

67 of 67 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

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?

  • Microglia in active MS lesions lack Tmem119.

    “Similarly, microglia in active MS lesions lack Tmem119 (Satoh et al., 2016; Zrzavy et al., 2017).”

    From Activated microglia drive demyelination via <scp>CSF1R</scp> signaling (2021) · cites this paper as Zrzavy et al., 2017

    The Results section (‘The contribution of resident microglia versus recruited macrophages in multiple sclerosis brain’) reports that, in early active lesions, an average of 43% of Iba1-positive cells were TMEM119-positive. TMEM119-positive cells became less numerous as active lesions advanced, but the paper does not say that microglia in active lesions lack TMEM119. (LLM, conf=0.91)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured
  • Microglial cells within active white matter lesions are characterized by the absence of homeostatic markers such as P2RY12 and an upregulation of CXCR4, indicating a shift to a disease-associated state.

    “Microglial cells within active white matter lesions are characterized by the absence of homeostatic markers such as P2RY12 and an upregulation of CXCR4, indicating a shift to a disease-associated state (31, 41, 42).”

    From The role of microglia in multiple sclerosis: implications for treatment with Bruton’s tyrosine kinase inhibitors (2025) · cites this paper as [41]

    The Results section reports that most microglia-like cells in classical active lesions are activated and lack P2RY12; the Discussion describes this as loss of the homeostatic phenotype. The paper does not report CXCR4 upregulation in these cells, so that specific part of the claim is unsupported by this source. Page numbers were not available in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • TMEM119 has been shown to be downregulated in active MS lesions and other inflammatory conditions of the brain.

    “TMEM119 is one of the main homeostatic microglia markers that is not expressed on monocyte-derived macrophages and has been shown to be downregulated in active MS lesions and other inflammatory conditions of the brain47–49.”

    From CHIT1 at diagnosis predicts faster disability progression and reflects early microglial activation in multiple sclerosis (2024) · cites this paper as [47]

    The Results report that TMEM119 is present in only a subset of cells in early active MS lesions and that few TMEM119-positive cells remain in active lesion centres (Figures 1 and 4; page unavailable). The paper does not establish TMEM119 downregulation in other inflammatory brain conditions; it also distinguishes TMEM119 from P2RY12, the marker it describes as homeostatic. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • The phenotype of microglia observed in HDLS is similar to that found in an SOD1 ALS mouse model and in multiple sclerosis patients, in which the molecules associated with the homeostatic microglial phenotype (e.g., P2RY12, CSF-1R) are down-regulated and inflammatory markers are up-regulated.

    “Interestingly, the phenotype of microglia we observed in HDLS is similar to that found in an SOD1 ALS mouse model and in multiple sclerosis patients, in which the molecules associated with the homeostatic microglial phenotype (e.g., P2RY12, CSF-1R) are down-regulated and inflammatory markers are up-regulated [24, 57].”

    From Loss of homeostatic microglial phenotype in CSF1R-related Leukoencephalopathy (2020) · cites this paper as [57]

    Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

    Experimental — accuracy not yet measured
  • P2RY12+ cells expressing TSPO are substantially reduced in active lesions.

    “As reported previously (Zrzavy et al., 2017), P2RY12+ cells expressing TSPO were substantially reduced in active lesions (Fig. 2E–H).”

    From A quantitative neuropathological assessment of translocator protein expression in multiple sclerosis (2019) · cites this paper as Zrzavy et al., 2017

    The Results (Figure 4 caption; page unavailable) report that P2RY12 expression is massively reduced in TMEM119+ cells in initial lesions and falls further in early active lesions. The cited paper does not establish that the reduced P2RY12+ cells express TSPO; its reported co-staining is for P2RY12 and TMEM119. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

Self-check

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

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

1 of the 68 references couldn’t be matched to a known paper.

Research works printed but not linked: 2

  1. Babinski J Recherches sur l’anatomie pathologique de la sclerose en plaque et étude comparative des diverses variétés de la scleroses de la moelle. Arch Physiol 1885; 5: 186– 207.
  2. Marburg O Die sogenannte akute multiple Sklerose. J Psychiatric Neurol 1906; 27: 1– 100

Cited by

Sorted by citations

Authors
Zrzavy, T., Hametner, S., Wimmer, I., Butovsky, O., Weiner, H. L., & Lassmann, H.
Affiliations
  • Medical University of Vienna (AT)
  • Brigham and Women's Hospital (US)
Corresponding author
Lassmann, Hans
Venue
Brain
Published
2017-05-24
Volume
140
Issue
7
Pages
1900-1913
ISSN
  • 0006-8950 (ISSN-L)
  • 1460-2156
OpenAlex
W2620266814
Cited by
684
References
68
Citations by year
2026: 62 · 2025: 65 · 2024: 78 · 2023: 87 · 2022: 92 · 2021: 116 · 2020: 71 · 2019: 60 · 2018: 43 · 2017: 10
FWCI
39.52
Type
journal article
Language
en
Open access
Locations
  • Brain (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
Funders
  • NIH (R01NS088137)
  • National Multiple Sclerosis Society (5092A1)
Topics
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Multiple Sclerosis Research Studies
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Inflammasome and immune disorders
Keywords
multiple sclerosis, microglia, macrophages, homeostatic microglia, microglial activation, P2Y12 receptor, TMEM119, normal-appearing white matter, demyelination, neurodegeneration, lesion activity, disease duration, pro-inflammatory phenotype, anti-inflammatory phenotype, phagocytosis, oxidative damage, antigen presentation, T cell costimulation, microglial origin
MeSH terms
Adult, Aged, Aged, 80 and over, Aging, Demyelinating Diseases, Female, Homeostasis, Humans, Macrophage Activation, Male, Membrane Proteins, Middle Aged, Multiple Sclerosis, Nerve Degeneration, Case-Control Studies, Microglia, Receptors, Purinergic P2Y12, White Matter

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.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review