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Reyes et al. Neuroimmunol Neuroinflammation 2020;7:215-33 Neuroimmunology
DOI: 10.20517/2347-8659.2020.13 and Neuroinflammation

Review Open Access

Microbiome meets microglia in neuroinflammation

and neurological disorders

Rachel E. N. Reyes, Zeyu Zhang, Lei Gao, Liana Asatryan
School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA.

Correspondence to: Dr. Liana Asatryan, School of Pharmacy, University of Southern California, 1985 Zonal Ave, Los Angeles,
CA 90033, USA. E-mail: asatryan@usc.edu

How to cite this article: Reyes REN, Zhang Z, Gao L, Asatryan L. Microbiome meets microglia in neuroinflammation and
neurological disorders. Neuroimmunol Neuroinflammation 2020;7:215-33.
http://dx.doi.org/10.20517/2347-8659.2020.13
Received: 2 Feb 2020 First Decision: 27 Feb 2020 Revised: 6 Mar 2020 Accepted: 25 Mar 2020 Available online: 16 Jun 2020

Science Editor: Jeffrey Bajramovic Copy Editor: Jing-Wen Zhang Production Editor: Tian Zhang

Abstract
One of the emerging hot topics in biosciences is the intriguing link between gut microbial communities and
its influences outside the gastrointestinal tract, such as the central nervous system (CNS), including its
cognitive activities and immune responses. Beyond its neuroprotective properties, microglia are also critical
for neuronal synaptic pruning and neural remodeling during CNS development. Prolonged microglia activation
and neuroinflammation are considered key contributors to neurological disorders. In this regard, it is becoming
increasingly important to consider the potential influences underlying the crosstalk between the intestinal
microbiota ecosystem and host when determining biomarkers of disease and treatment efficacy. The commensal
microbiota is critical for immune development and continuous function through the recognition of bacteria-
produced and regulated metabolites. In cases of microbial dysbiosis and microglial dysfunction, chronic
neuroinflammation may persist, leading to the propagation of neurological disorders. To address potential
mechanisms, this review focuses on the microbiota-gut-brain axis as it relates to communication pathways
that have been linked to aberrant CNS immune activity and pathology. We also address anti-inflammatory and
neuroprotective mediators which may counteract these detrimental activities. Finally, we explore the potential
benefits of current and novel microbiome-targeted approaches to treat neuroinflammation and consequential
neurological disease.

Keywords: Microglia, neuroinflammation, neurological disorders, microbiota, gut-brain axis, vagus nerve, short
chain fatty acids, hypothalamic-pituitary-adrenal axes, hypothalamic-pituitary-gonadal axes, therapeutic
interventions

© The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

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