Cited by 58Alzheimer's disease research and treatmentsNeurogenesis and neuroplasticity mechanismsNeuroinflammation and Neurodegeneration Mechanisms

Activated CX3CL1/Smad2 Signals Prevent Neuronal Loss and Alzheimer's Tau Pathology-Mediated Cognitive Dysfunction

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Fan, Qingyuan, He, Wanxia, Gayen, Manoshi, Benoit, Marc Robert, Luo, Xiaoyang, Hu, Xiangyou, Yan, Riqiang·2020·The Journal of Neuroscience

Abstract

Neurofibrillary tangles likely cause neurodegeneration in Alzheimer's disease (AD). We demonstrate that the CX3CL1 C-terminal domain can upregulate neurogenesis, which may ameliorate neurodegeneration. Here we generated transgenic (Tg-CX3CL1) mice by overexpressing CX3CL1 in neurons. Tg-CX3CL1 mice exhibit enhanced neurogenesis in both subgranular and subventricular zones. This enhanced neurogenesis correlates well with elevated expression of TGF-β2 and TGF-β3, and activation of their downstream signaling molecule Smad2. Intriguingly, the enhanced adult neurogenesis was mitigated when Smad2 expression was deleted in neurons, supporting a role for the CX3CL1–TGF-β2/3–Smad2 pathway in the control of adult neurogenesis. When Tg-CX3CL1 mice were crossed with Alzheimer's PS19 mice, which overexpress a tau P301S mutation and exhibit age-dependent neurofibrillary tangles and neurodegeneration, overexpressed CX3CL1 in both male and female mice was sufficient to rescue the neurodegeneration, increase survival time, and improve cognitive function. Hence, we provide in vivo evidence that CX3CL1 is a strong activator of adult neurogenesis, and that it reduces neuronal loss and improves cognitive function in AD. SIGNIFICANCE STATEMENT This study will be the first to demonstrate that enhanced neurogenesis by overexpressed CX3CL1 is mitigated by disruption of Smad2 signaling and is independent of its interaction with CX3CR1. Overexpression of CX3CL1 lengthens the life span of PS19 tau mice by enhancing adult neurogenesis while having minimal effect on tau pathology. Enhancing neuronal CX3CL1, mainly the C-terminal fragment, is a therapeutic strategy for blocking or reversing neuronal loss in Alzheimer's disease or related neurodegenerative disease patients.

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Crossref · 10.1523/jneurosci.1333-19.2019

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  • Fractalkine upregulation reduces tau pathology and neurodegeneration in an animal model, and elevated plasma fractalkine levels were protective in a stroke population.

    “upregulation of fractalkine, a chemokine that dampens the pro-inflammatory state of microglia and plays a role in adult neurogenesis, has been shown to reduce tau pathology and neurodegeneration in an animal model [57], and elevated plasma fractalkine levels were protective in a stroke population [58].”

    From Evaluation of exploratory fluid biomarkers from a phase 1 senolytic trial in mild Alzheimer's disease (2025) · cites this paper as [57]

    The Results section reports that CX3CL1 overexpression partially rescued neuronal loss in PS19 tau mice, but did not significantly change measured tau levels. The Discussion likewise says it prevented or reduced neurodegeneration without an obvious reduction in tau pathology. The plasma fractalkine finding is attributed to a different citation [58] and is not assessed here. (LLM, conf=0.94)

    Experimental — accuracy not yet measured
  • 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).”

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Authors
Fan, Q., He, W., Gayen, M., Benoit, M. R., Luo, X., Hu, X., & Yan, R.
Affiliations
  • Cleveland Clinic (US)
  • UConn Health (US)
Corresponding author
Yan, Riqiang
Venue
The Journal of Neuroscience
Published
2019-12-10
Volume
40
Issue
5
Pages
1133-1144
ISSN
  • 0270-6474 (ISSN-L)
  • 1529-2401
OpenAlex
W2995210504
Cited by
58
References
43
Citations by year
2026: 5 · 2025: 10 · 2024: 8 · 2023: 9 · 2022: 13 · 2021: 11 · 2020: 2
FWCI
4.46
Type
journal article
Language
en
Open access
Locations
  • Journal of Neuroscience (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health
  • National Institute on Aging (R01AG025493, RF1AG046929, RF1AG058261, RF1AG025493, R01 AG058261, R01AG046929)
  • National Institute of Neurological Disorders and Stroke (RF1NS074256, R01NS074256)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Neuroscience › Developmental Neuroscience › Neurogenesis and neuroplasticity mechanisms
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
fractalkine, Smad2, TGF-beta2, TGF-beta3, adult neurogenesis, Alzheimer's disease, tau pathology, neurofibrillary tangles, neuronal loss, cognitive impairment, PS19 mice, neurodegeneration, subventricular zone, subgranular zone
MeSH terms
Alzheimer Disease, Animals, Disease Models, Animal, Female, Male, Mice, Transgenic, Neurons, tau Proteins, Smad2 Protein, Chemokine CX3CL1, Neurogenesis, Spatial Memory

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