One fundamental component of systemic homeostasis is the gut microbiota, which communicates with
the CNS via microbial metabolite production, the peripheral nervous system, and regulation of
tryptophan metabolism. Over the past 10–15 years, research focused on the microbiota–gut–brain
axis has culminated in the discovery that dysbiosis, or an imbalance between commensal and
pathogenic gut bacteria, can promote CNS pathologies. Conversely, a properly regulated and
well-balanced microbiome supports CNS homeostasis and reduces the incidence and extent of
pathogenic neuroinflammation. This review will discuss the role of the gut microbiota in exacerbating
or alleviating neuroinflammation in neurodegenerative diseases, and potential microbiota-based
therapeutic approaches to reduce pathology in diseased states. CLICK TO REVIEW