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Updated: May 6, 2026
Culturing Microglia from the Neonatal and Adult Central Nervous System
Published on: August 9, 2013
Microglia modulate Aβ-dependent astrocyte reactivity in Alzheimer's disease
João Pedro Ferrari-Souza1,2, Guilherme Povala2, Nesrine Rahmouni3,4
1Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Abstract:
Experimental evidence suggests that activated microglia induce astrocyte reactivity in neurodegenerative disorders, such as Alzheimer's disease (AD). In this study, we investigated the association between microglial activation and amyloid-β (Aβ) with reactive astrogliosis in individuals across the AD spectrum. We examined 101 individuals using positron emission tomography radiotracers to assess Aβ deposition ([18F]AZD4694), tau aggregation ([18F]MK-6240) and microglial activation ([11C]PBR28), along with plasma biomarkers for astrocyte reactivity (GFAP) and tau phosphorylation (p-tau217). We further evaluated 251 individuals with cerebrospinal fluid levels of the microglial marker sTREM2. We found that Aβ pathology was associated with astrocyte reactivity across cortical brain regions only in the presence of microglial activation. The microglia-dependent effects of Aβ on astrocyte reactivity were further related to cognitive impairment through tau phosphorylation and aggregation. Our results suggest that microglial activation plays a key role in Aβ-related astrocyte reactivity, which, in turn, contributes to downstream pathological features of AD.
Insights
Microglial activation links amyloid-β (Aβ) pathology to astrocyte reactivity in Alzheimer's disease (AD). This microglia-dependent process contributes to cognitive decline via tau phosphorylation and aggregation, highlighting a key pathway in AD progression.
Area of Science:
- Neuroscience
- Neuropathology
- Immunology
Background:
- Activated microglia are implicated in astrocyte reactivity in neurodegenerative diseases like Alzheimer's disease (AD).
- Understanding the interplay between microglial activation, amyloid-β (Aβ) pathology, and reactive astrogliosis is crucial for AD research.
- The specific mechanisms linking these pathologies across the AD spectrum require further elucidation.
Purpose of the Study:
- To investigate the association between microglial activation, Aβ deposition, and reactive astrogliosis in individuals with varying degrees of AD.
- To explore the role of microglial activation as a mediator in the relationship between Aβ and astrocyte reactivity.
- To determine how Aβ-induced astrocyte reactivity, influenced by microglia, relates to cognitive impairment and tau pathology.
Main Methods:
- Utilized positron emission tomography (PET) with radiotracers ([18F]AZD4694, [18F]MK-6240, [11C]PBR28) to assess Aβ deposition, tau aggregation, and microglial activation in 101 individuals.
- Measured plasma biomarkers GFAP (astrocyte reactivity) and p-tau217 (tau phosphorylation).
- Analyzed cerebrospinal fluid (CSF) sTREM2 levels in an additional 251 individuals.
Main Results:
- Aβ pathology correlated with astrocyte reactivity in cortical regions, but only when microglial activation was present.
- Microglial activation mediated the effect of Aβ on astrocyte reactivity.
- This microglia-dependent Aβ-astrocyte interaction was linked to cognitive impairment, mediated by tau phosphorylation and aggregation.
Conclusions:
- Microglial activation is a key factor in the development of Aβ-related astrocyte reactivity in Alzheimer's disease.
- Reactive astrogliosis, driven by microglia in response to Aβ, contributes to downstream pathological features, including tau pathology and cognitive decline.
- Targeting microglial activation may represent a therapeutic strategy for mitigating Aβ-driven neuroinflammation and neurodegeneration in AD.
