Differential Expression Of Microrna In Ulcerative Colitis And The Research About The Function Of MicroRNA-181a

BackgroundUlcerative colitis (UC) is a chronic and non-specific condition of the intestinalinflammation. Bloody purulent stool, recurrent diarrhea, abdominal pain are the mainclinical manifestations.Lesions are located in the mucosa and submucosa of the colon The exact cause of UC is unknown, a variety of factors such as genetics, infectious,environmental, immunity play important role in the pathogenesis of UC.The intestinalimmune system dysregμlation and increased secretion of proinflammatory cytokines maybe the main pathogenesis of intestinal inflammation.MicroRNA (miRNA) are a class of endogenous small（18-24nucleotide）non-codingRNA (nocoding RNA, ncRNA). MiRNA bind to sequences in the3’untranslated region(UTR) of target mRNAs and inhibite the expression of the target gene.miRNA areinvolved in the process of a series of important biological processes, such as cancer,inflammation, cell proliferation, apoptosis.This study aimed to lead to new insights intoUC pathogenesis.Aims：The purpose of this study was to analysis the result of miRNA microarray and thenselect five miRNA which were differential expression in UC: miR-181a, miR-181b,miR-182, miR-146a, miR-101to be verified using Real-time quantitative RT-PCR.Explore the role of miR-181a and its target gene TNF-α in the molecμlar mechanismsunderlying the pathophysiology of UC.Methods1.We analysed the miRNA microarray and selected five miRNA:miR-181a、miR-181b、miR-182、miR-146a、miR-101and verified the result using real-time quantitativeRT-PCR. 2We predicted the potential target gene of miRNA-181a using bioinformatics methodsand detected the level of TNF-α in colonic mucosa of ulcerative colitis patients andhealthy controls using western blot3.We constructed a pGL-3M plasmids for theTNF-α3’UTR and mutant,the targetedrelationship of miR-181a and TNF-α was evaluated by luciferase reporter gene assayand western blot.4. Overexpression and inhibition of the expression of miR-181a expression to detectthe level of the TNF-α and IκB.Results1Using real-time quantitative RT-PCR assay,we found four kinds of miRNA wereconsistent with the result of the microarray:miR-181a, miR-181b downregulated,miR-146a, miR-101expression increases.2The expression of TNF-α was significantly higher in UC groupt han in healthy controlgroup3TNF-α was identified as a target gene of miR-181a using luciferase array and westernblot.4The expression of IκB was increased while over-expression of the miR-181a,anddecreased while inhibiting the expression of miR-181aConclusionsWe analysed the microarray results and tested five miRNA using real-time quantitativeRT-PCR: miR-146a, miR-101were increased,miR-181a, miR-181b, miR-182weredecreased. We also demonstrated that TNF-α was a target gene of miR-181a. Our resultdemonstrated an important role for miR-181a in the molecular basis and pathophysiologyof UC.