P036 MicroRNA composition of colon crypt-top and crypt-bottom epithelial cells in Ulcerative Colitis

Abstract

Abstract Background Ulcerative colitis (UC) is a chronic relapsing large intestine condition of inflammatory origin1. One of the most common features of UC is the injury of the intestinal barrier, which is composed primarily of colonic epithelial cells (CEpCs)2. The aim of this study was to identify UC-induced miRNA markers in CEpCs by determining the miRNA expression profile changes in crypt-top and crypt-bottom CEpC populations during active (aUC) and inactive (iUC) UC. Methods Crypt-top and crypt-bottom CEpCs were sorted from biopsies of healthy control (HC) individuals (n=19), patients with aUC (n=17) and iUC (n=15) using FACS technology. Total RNA was extracted, small RNA sequencing libraries were prepared and sequenced using Illumina platform. Sequencing data was processed with nextflow-core/smrnaseq pipeline. Differential expression, correlation, miRNA-target interactions, gene set enrichment analyses and data visualisation were performed using Rstudio software packages DESeq2, isomiRs, multimiR, SingleCellExperiment, clusterProfiler, ReactomePA, etc. The miRNAs with an adjusted p-value < 0.05, and absolute value of log2 fold change > 1 were considered to be significantly differentially expressed. Results 432 unique miRNAs were identified in samples. Changes of expression profile during aUC were identified in crypt-bottom CEpCs (compared to: (i) HC - 23 miRNAs, (ii) iUC - 22 miRNAs), as well as in crypt-top CEpCs (compared to: (i) HC - 28 miRNAs, (ii) iUC - 9 miRNAs). Also, 7 miRNAs were differentially expressed in crypt-bottom CEpCs and 3 miRNAs in crypt-top CEpCs during iUC compared to HC. 5 miRNAs were identified to be differentially expressed during aUC, 2 miRNAs - during iUC, and 11 miRNAs in HC when comparing expression profiles of crypt-bottom and crypt-bottom CEpCs. We also identified 16 and 14 miRNAs which expression in crypt-bottom and crypt-top CEpCs moderately (0.5<rho<0.7) correlated with Mayo score, respectively. Finally, the gene sets of pathways revealed the involvement of several miRNAs in biological processes and molecular functions associated with UC pathogenesis. Conclusion The changes of expression profiles of miRNAs revealed that crypt-top and crypt-bottom CEpCs respond to inflammation differently, the expression of these miRNAs reflects disease activity and modulates the processes of UC pathogenesis. References