Estinal barrierGastroenterology. Author manuscript; MMP-9 MedChemExpress offered in PMC 2022 June 01.Mahurkar-Joshi et al.Pagedysfunction, motor abnormalities, and visceral pain in IBS6,7. Although the etiology of IBS is incompletely understood, there’s evidence that genetic, environmental, and epigenetic8 elements play a role. Expression of protein-coding genes (mRNAs) has been previously investigated in IBS9,ten, however, a majority of transcripts are non-coding11. MicroRNAs (miRNAs) are smaller (21-23 bp) non-coding RNAs that regulate gene expression either by base-pairing to target mRNAs or through endonucleolytic mRNA cleavage12. MiRNAs have been implicated in several GI physiologic and pathophysiologic mechanisms and studied extensively in intestinal immune and inflammatory diseases, however, studies in IBS are very heterogeneous130. Most IBSrelated miRNA studies were restricted to IBS-D girls. A few of the miRNAs studied have been recommended to play a function in visceral hypersensitivity and barrier dysfunction, that are crucial pathophysiological mechanisms in IBS21. One example is, miR-29a targets the glutamine synthetase gene (GLUL) and increases intestinal permeability20, and miR-199a/b targets transient receptor potential cation channel subfamily V member 1 (TRPV1), as well as a decreased expression of this miRNA correlates with visceral hypersensitivity15. Nevertheless, there is a lack of a global overview of validated miRNA modifications, differences in target gene expression, and linked pathways in IBS, particularly IBS-C. We hypothesize that 1) IBS and BH subtypes are connected with alterations in expression of mucosal miRNA and their target genes two) IBS-associated miRNAs regulate functions/pathways linked with IBS pathophysiology. We addressed these hypotheses by aiming to identify: 1) differentially expressed miRNAs in between IBS and BH subtypes vs. healthful controls (HCs), two) targets of differentially regulated miRNA and linked pathways by silencing or overexpressing them in intestinal epithelial cell lines, 3) differentially regulated miRNA target genes in the colonic mucosa of IBS individuals, and four) testing possible functional roles for the miRNAs identified.Author Manuscript Author Manuscript Author Manuscript Author Manuscript MethodsStudy Population IBS individuals and HCs ages 18-55 were recruited primarily by neighborhood advertisement. The diagnosis of IBS and BH subtypes was depending on Rome III criteria22 and confirmed by a clinician with experience in IBS. HCs had no individual or family members history of IBS or other chronic discomfort conditions. Additional exclusion criteria for all subjects MT2 list included: infectious or inflammatory issues, active psychiatric illness over the past six months assessed by structured clinical interview for the DSM-IV (MINI)23, use of corticosteroids or narcotics, or present tobacco or alcohol abuse. Participants had been compensated. The study was authorized by the UCLA Institutional Evaluation Board, and subjects signed a written informed consent before the study. General IBS symptoms, abdominal discomfort, and bloating severity more than the prior week had been assessed with numeric rating scales (0-20)24. Present anxiousness and depression symptoms had been measured using the Hospital Anxiousness and Depression (HAD) scale25. Scores have been classified as non-case (0-7), doubtful case (8-10), or definite case (11).Gastroenterology. Author manuscript; offered in PMC 2022 June 01.Mahurkar-Joshi et al.PageColonic mucosal tissue collectionAuthor Manuscript Author Manuscript Author Manuscript.