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Figure 3. Specific bacterial signatures of gut dysbiome and pathobiome associated with neuroinflammation and AD neuropathology. The relative abundance of gut bacterial genera consistently reported as upregulated or downregulated across multiple studies comparing the gut microbiomes of AD patients with healthy controls suggests an imbalance in these gut microbial communities. This imbalance is likely connected to disruptions in gut-derived microbial metabolites, neurotransmitters, gut permeability, glucose/insulin sensitivity, and neuroinflammatory responses. Further, these imbalances instigate neuroinflammation via the gut-brain-immune axis, either via interactions between bacterial surface components and intestinal immune cells or via translocation of harmful metabolites and bacterial components across the blood-brain barrier. This progression ultimately leads to aggravated neuroinflammatory triggers and associated neuropathology observed in AD. ▲: Increased, ▼: decreased. AD: Alzheimer’s disease.