Cited by 113Alzheimer's disease research and treatmentsNeuroinflammation and Neurodegeneration MechanismsNeurological Disease Mechanisms and Treatments

CX3CR1 deficiency aggravates amyloid driven neuronal pathology and cognitive decline in Alzheimer’s disease

Open access
Puntambekar, Shweta S., Moutinho, Miguel, Lin, Peter Bor-Chian, Jadhav, Vaishnavi, Tumbleson-Brink, Danika, Balaji, Ananya, Benito, Martin Alvarado, Xu, Guixiang +4 more·2022·Molecular Neurodegeneration

Abstract

Background: Despite its identification as a key checkpoint regulator of microglial activation in Alzheimer’s disease, the overarching role of CX3CR1 signaling in modulating mechanisms of Aβ driven neurodegeneration, including accumulation of hyperphosphorylated tau is not well understood. Methodology: Accumulation of soluble and insoluble Aβ species, microglial activation, synaptic dysregulation, and neurodegeneration is investigated in 4- and 6-month old 5xFAD;Cx3cr1+/+ and 5xFAD;Cx3cr1−/− mice using immunohistochemistry, western blotting, transcriptomic and quantitative real time PCR analyses of purified microglia. Flow cytometry based, in-vivo Aβ uptake assays are used for characterization of the effects of CX3CR1-signaling on microglial phagocytosis and lysosomal acidification as indicators of clearance of methoxy-X-04+ fibrillar Aβ. Lastly, we use Y-maze testing to analyze the effects of Cx3cr1 deficiency on working memory. Results: Disease progression in 5xFAD;Cx3cr1−/− mice is characterized by increased deposition of filamentous plaques that display defective microglial plaque engagement. Microglial Aβ phagocytosis and lysosomal acidification in 5xFAD;Cx3cr1−/− mice is impaired in-vivo. Interestingly, Cx3cr1 deficiency results in heighted accumulation of neurotoxic, oligomeric Aβ, along with severe neuritic dystrophy, preferential loss of post-synaptic densities, exacerbated tau pathology, neuronal loss and cognitive impairment. Transcriptomic analyses using cortical RNA, coupled with qRT-PCR using purified microglia from 6 month-old mice indicate dysregulated TGFβ-signaling and heightened ROS metabolism in 5xFAD;Cx3cr1−/− mice. Lastly, microglia in 6 month-old 5xFAD;Cx3cr1−/− mice express a ‘degenerative’ phenotype characterized by increased levels of Ccl2, Ccl5, Il-1β, Pten and Cybb along with reduced Tnf, Il-6 and Tgfβ1 mRNA. Conclusions: Cx3cr1 deficiency impairs microglial uptake and degradation of fibrillar Aβ, thereby triggering increased accumulation of neurotoxic Aβ species. Furthermore, loss of Cx3cr1 results in microglial dysfunction typified by dampened TGFβ-signaling, increased oxidative stress responses and dysregulated pro-inflammatory activation. Our results indicate that Aβ-driven microglial dysfunction in Cx3cr1−/− mice aggravates tau hyperphosphorylation, neurodegeneration, synaptic dysregulation and impairs working memory.

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 · 10.1186/s13024-022-00545-9

Cites

55 of 55 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?

  • Earlier studies on other microglial AD risk genes reported opposing effects on AD-related pathologies using various animal models at different ages.

    “Earlier studies on other microglial AD risk genes reported opposing effects on AD-related pathologies using various animal models at different ages (8–14).”

    From The effect of Abi3 locus deletion on the progression of Alzheimer’s disease-related pathologies (2023) · cites this paper as [12]

    The Background reports divergent effects of CX3CR1 deficiency in different AD mouse models: reduced amyloid burden in early disease but worsened tau pathology in a tauopathy model. The Discussion also mentions AD-related microglial genes TREM2 and APOE, but does not report opposing effects of those other genes across models and ages. No page numbers are available in our copy. (LLM, conf=0.85)

    Experimental — accuracy not yet measured
  • Microglia can have differential effects on Alzheimer's disease pathology depending on the disease stage.

    “These studies have led to the notion that microglia can have differential effects on AD pathology depending on the disease stage.”
  • Deletion of CX3CR1 or depression of the CX3CL1/CX3CR1 axis reduces Aβ deposition but exacerbates tau pathology, such as increased phosphorylation and aggregation of tau, and this is associated with worsened behavioral and cognitive impairments.

    “Deletion of CX3CR1 or depression of the CX3CL1/CX3CR1 axis reduces Aβ deposition [130–132] but exacerbates tau pathology, such as increased phosphorylation and aggregation of tau, and this is associated with worsened behavioral and cognitive impairments [132–137] (Fig. 1).”

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

Cited by

Sorted by citations

Authors
Puntambekar, S. S., Moutinho, M., Lin, P. B.-C., Jadhav, V., Tumbleson-Brink, D., Balaji, A., Benito, M. A., Xu, G., Oblak, A., Lasagna-Reeves, C. A., Landreth, G. E., & Lamb, B. T.
Affiliations
  • Indiana University Indianapolis (US)
  • Indiana University School of Medicine (US)
  • University of Washington (US)
  • Indiana Clinical and Translational Sciences Institute (US)
Corresponding author
  • Puntambekar, Shweta S.
  • Lamb, Bruce T.
Venue
Molecular Neurodegeneration
Published
2022-06-28
Volume
17
Issue
1
Pages
47-47
ISSN
1750-1326 (ISSN-L)
OpenAlex
W4283643624
Cited by
113
References
55
Citations by year
2026: 26 · 2025: 33 · 2024: 23 · 2023: 26 · 2022: 5
FWCI
13.45
Type
journal article
Language
en
Open access
Locations
  • Molecular Neurodegeneration (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Purdue University Indianapolis (Indiana University) (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • IUScholarWorks (Indiana University) (submittedVersion, cc-by)
Funders
National Institutes of Health (NIH RF1AG051495, 1RF1AG069425-01)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Life Sciences › Neuroscience › Neurology › Neurological Disease Mechanisms and Treatments
Keywords
CX3CR1, Alzheimer's disease, amyloid-beta, microglial dysfunction, 5xFAD mice, tau pathology, neurodegeneration, cognitive decline, TGF-beta signaling, oxidative stress, microglial phagocytosis, lysosomal acidification, microglial polarization, synaptic loss, working memory, neuroinflammation, amyloid plaques, amyloid-beta oligomers
MeSH terms
CX3C Chemokine Receptor 1, Alzheimer Disease, Amyloidosis, Animals, Neurons, Transforming Growth Factor beta, Mice, Plaque, Amyloid, Amyloidogenic Proteins, Cognitive Dysfunction

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