Neuroinflammatory Mechanisms in Alzheimer’s Disease

Alzheimer’s disease is characterised not only by the accumulation of amyloid-β plaques and tau tangles but also by a sustained inflammatory response within the central nervous system. Resident microglia and astrocytes become chronically activated by aggregated proteins and damaged neurons, releasing pro-inflammatory cytokines, chemokines and reactive oxygen species. This milieu promotes blood–brain barrier permeability, facilitating peripheral immune cell entry and further exacerbating local inflammation. Intracellular sensors such as the cyclic GMP–AMP synthase–stimulator of interferon genes (cGAS–STING) pathway detect mislocalized nucleic acids, triggering type I interferon responses that impair neuronal transcriptional networks responsible for synaptic resilience. Complement activation and inflammasome assembly drive synaptic pruning and neuronal loss. Concurrently, vascular inflammation and oxidative stress undermine cerebral blood flow and amyloid clearance, establishing a feed-forward cycle of neurodegeneration. Insight into these interconnected events has underscored neuroinflammation as both a mediator of neuronal injury and a promising target for therapy.

Research from Nature Portfolio

Recent studies have illuminated a critical axis linking tau pathology to microglial dysfunction. Pathogenic tau species provoke cytosolic mitochondrial DNA leakage, activating microglial cGAS and inducing a type I interferon response that suppresses the neuronal myocyte enhancer factor 2C (MEF2C) network. Genetic ablation or pharmacological inhibition of cGAS in tauopathy models preserved synaptic integrity, restored plasticity and prevented cognitive decline, highlighting the therapeutic potential of targeting cGAS–IFN signalling. Complementary work has demonstrated that chronically elevated interferon in the ageing brain downregulates MEF2C in microglia, promoting an exaggerated inflammatory phenotype that impairs cognition. Restoration of MEF2C function ameliorated microglial over-activation, underscoring its role as a brake on neuroinflammation and as a key determinant of neural resilience.

Neuroinflammatory Mechanisms in Alzheimer’s Disease publication trend

The graph below shows the total number of articles in neuroinflammatory mechanisms in alzheimer’s disease across all publications each year (not limited to Nature Index journals).

Technical terms

Microglia: Resident immune cells of the brain that mediate inflammatory and phagocytic responses.

cGAS–STING pathway: Intracellular DNA-sensing mechanism that activates type I interferon production.

Type I interferon (IFN-I): A class of cytokines that coordinate antiviral and inflammatory gene expression.

Myocyte enhancer factor 2C (MEF2C): Neuronal transcription factor crucial for synaptic health and cognitive resilience.

Cerebral amyloid angiopathy (CAA): Deposition of amyloid-β in cerebral vessel walls leading to vascular dysfunction.

Blood–brain barrier (BBB): Selective endothelial interface regulating exchange between the bloodstream and neural tissue.

NLRP3 inflammasome: Multiprotein complex that activates pro-inflammatory cytokines in innate immunity.

References

1. Tau activation of microglial cGAS–IFN reduces MEF2C-mediated cognitive resilience. Nature Neuroscience (2023).
2. Mef2C restrains microglial inflammatory response and is lost in brain ageing in an IFN-I-dependent manner. Nature Communications (2017).
3. Border-associated macrophages promote cerebral amyloid angiopathy and cognitive impairment through vascular oxidative stress. Molecular Neurodegeneration (2023).
4. Blockade of STING activation alleviates microglial dysfunction and a broad spectrum of Alzheimer’s disease pathologies. Experimental & Molecular Medicine (2024).
5. Nanotechnology for microglial targeting and inhibition of neuroinflammation underlying Alzheimer’s pathology. Translational Neurodegeneration (2024).