Functional states of microglia and astrocytes in the neuroimmune environment.
| Cell type | Functional state | Key molecular markers | Functional features | Associated conditions |
|---|---|---|---|---|
| Microglia | Homeostatic microglia | P2RY12, TMEM119, CX3CR1 | Immune surveillance, synaptic monitoring, clearance of cellular debris, maintenance of tissue homeostasis | Healthy brain physiology [22, 153] |
| Microglia | Activated inflammatory microglia | CD68, MHC-II, IL-1β, TNF | Production of inflammatory cytokines, reactive oxygen species generation, antigen presentation, enhanced phagocytosis | Infection, acute injury, neuroinflammation [97, 154] |
| Microglia | Disease-associated microglia (DAM) | TREM2, APOE, LPL, CST7 | Enhanced phagocytosis of protein aggregates, lipid metabolism adaptation, response to neurodegenerative pathology | Alzheimer’s disease, Parkinson’s disease, neurodegeneration [155, 156] |
| Astrocytes | Homeostatic astrocytes | GLT-1/EAAT2, Kir4.1; GFAP low or regionally restricted under basal conditions | Regulation of neurotransmitter levels, metabolic support to neurons, potassium buffering, neurovascular coupling | Healthy brain physiology [40, 46] |
| Astrocytes | Neuroprotective reactive astrocytes | Increased GFAP, antioxidant pathways, trophic factors | Support neuronal survival, limit oxidative stress, promote tissue stabilization and repair | Early injury response, recovery phases [142, 144] |
| Astrocytes | Neurotoxic reactive astrocytes | Complement component C3, inflammatory mediators | Amplification of inflammatory signaling, disruption of synaptic function, promotion of neuronal injury | Neurodegenerative disease, chronic neuroinflammation [139, 140] |
MMN: Conceptualization, Methodology, Investigation, Resources, Data curation, Formal analysis, Visualization, Writing—original draft, Writing—review & editing. The author read and approved the submitted version.
The author declares no conflicts of interest.
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