Intestinal Microbiota and miRNA in IBD: A Narrative Review about Discoveries and Perspectives for the Future

Abstract

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC) and comprises a chronic gastrointestinal tract disorder characterized by hyperactive and dysregulated immune responses to environmental factors, including gut microbiota and dietary components. An imbalance of the intestinal microbiota may contribute to the development and/or worsening of the inflammatory process. MicroRNAs (miRNAs) have been associated with various physiological processes, such as cell development and proliferation, apoptosis, and cancer. In addition, they play an important role in inflammatory processes, acting in the regulation of pro- and anti-inflammatory pathways. Differences in the profiles of miRNAs may represent a useful tool in the diagnosis of UC and CD and as a prognostic marker in both diseases. The relationship between miRNAs and the intestinal microbiota is not completely elucidated, but recently this topic has gained prominence and has become the target of several studies that demonstrate the role of miRNAs in the modulation of the intestinal microbiota and induction of dysbiosis; the microbiota, in turn, can regulate the expression of miRNAs and, consequently, alter the intestinal homeostasis. Therefore, this review aims to describe the interaction between the intestinal microbiota and miRNAs in IBD, recent discoveries, and perspectives for the future.

Keywords: Crohn’s disease; dysbiosis; inflammatory bowel; intestinal microbiota; microRNA; ulcerative colitis.

Figure 1

Interaction between microRNA and microbiota in Inflammatory Bowel Disease. AEIC: adherent-invasive E. coli; IFN-γ: interferon-gamma; IL: interleukin; NF-κB: nuclear factor-kappa B; ROS: reactive oxygen species; SCFAs: short-chain fatty acids; TNF-α: tumor necrosis factor alpha.

Figure 2

Complex relationship of intestinal microbiota and microRNA in Inflammatory Bowel Disease (IBD). The intersection between IBD, microbiota, and miRNA represent the points of influence between the disease and the profiles of intestinal bacteria and miRNA. A = the main bacteria involved in dysbiosis in IBD; B = the main miRNAs involved with IBD; C = complex interaction between intestinal bacteria and miRNA profiles and the disease, which can offer new perspectives regarding evolution and control of the IBD, still underexplored. IBD = inflammatory bowel disease; ↓ = reduced bacteria and reduced miRNA in IBD; ↑ = increased bacteria and increased miRNA in IBD.