The Relationship Between Gut Microbiota and Inflammatory Diseases: The Role of Macrophages.

Ji Wang,Yan-Dong Wang,Wei-Dong Chen

doi:10.3389/fmicb.2020.01065

Abstract

Gut microbiota, an integral part of the human body, comprise bacteria, fungi, archaea, and protozoa. There is consensus that the disruption of the gut microbiota (termed “gut dysbiosis”) is influenced by host genetics, diet, antibiotics, and inflammation, and it is closely linked to the pathogenesis of inflammatory diseases, such as obesity and inflammatory bowel disease (IBD). Macrophages are the key players in the maintenance of tissue homeostasis by eliminating invading pathogens and exhibit extreme plasticity of their phenotypes, such as M1 or M2, which have been demonstrated to exert pro- and anti-inflammatory functions. Microbiota-derived metabolites, short-chain fatty acids (SCFAs) and Gram-negative bacterial lipopolysaccharides (LPS), exert anti-inflammatory or pro-inflammatory effects by acting on macrophages. Understanding the role of macrophages in gut microbiota-inflammation interactions might provide us a novel method for preventing and treating inflammatory diseases. In this review, we summarize the recent research on the relationship between gut microbiota and inflammation and discuss the important role of macrophages in this context.

Highlights

Gut microbes, an essential part of the microbiota ecosystem, outnumbers human cells by 10-fold (Zhang et al, 2015)
inflammatory bowel disease (IBD) could be ameliorated via the M1 to M2 switch in the colitis mouse model (Zhu et al, 2016). These findings suggest a strong correlation between macrophages and the inflammatory diseases and imply that macrophages participate in the inflammatory process mainly by shifting from the pro-inflammatory (M1) to anti-inflammatory (M2) phenotype (Porcheray et al, 2005)
This review provides current understanding of the role of macrophages in gut microbiota and inflammation interactions

Summary

Introduction

An essential part of the microbiota ecosystem, outnumbers human cells by 10-fold (Zhang et al, 2015). As reviewed by Hakansson and Molin (2011) macrophages infiltrate tissues during inflammation and perform major functions, including antigen presentation, phagocytosis, and production of various cytokines and growth factors to participate in immune regulation. We summarize the current understanding of the link between gut microbiota and inflammation focusing on the roles of macrophages.

Results

Conclusion