A review of changes in the expression of microRNAs in ulcerative colitis

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) that causes inflammation and ulcers in the colon. The pathogenesis of UC is not well defined, but it is proposed that genetic and environmental factors result in an aberrant immune response to a subset of commensal enteric bacteria. A microRNA (miRNA) is a small non-coding RNA molecule (containing about 22 nucleotides), which functions in mRNA silencing and posttranscriptional regulation of gene expression. The aim of this article is to summarize the biogenesis pathway of microRNA and identify target genes involved in ulcerative colitis and summarize the most common changes in the expression of miRNAs in ulcerative colitis. Furthermore, we describe the pathophysiological roles of the miRNAs in UC. A search at electronic databases (Pubmed, Embase) was conducted between 1993 and 2021. Studies in recent years have been shown abnormal expression of several miRNAs such as miR-26b, miR-223, miR-31, miR-155 in colon tissue and peripheral blood in ulcerative colitis. Moreover, this abnormal expression is highly related to the disease activity of UC and colitis-associated cancer. We discussed the usefulness of microRNAs as biomarkers in the diagnosis, monitoring, and prognosis of ulcerative  colitis. Understanding the importance of miRNAs in ulcerative colitis may lead to future insights into disease pathogenesis, diagnosis, and treatment.