Gene expression regulation and polyadenylation in ulcerative colitis via long-chain RNA sequencing

Ulcerative colitis (UC) is an immune-mediated chronic intestinal disease, with a pathogenesis that remains incompletely understood. The purpose of this study is to analyze the difference of gene expression between UC patients and healthy controls using Oxford Nanopore Technology's long-read RNA sequencing (ONT-RNA-seq) and to explore how alternative polyadenylation (APA) site selection contributes to UC pathogenesis.

Colon tissue samples from UC and normal controls (NC) were collected, and total RNA was extracted and sequenced using ONT-RNA-seq technology. Various bioinformatics analyses were performed, including differential expression gene (DEG) analysis, functional enrichment analysis, APA site analysis, and prediction miRNAs and RNA binding proteins (RBPs) targets, to explore the molecular mechanism underlying UC.

ONT-RNA-seq analysis revealed that the expression levels of ACSF2, NPY, SLC26A3, BRINP3, and PKLPP2 were significantly lower in UC patients compared to the NC group, while the expression levels of CCL20, CCL21, CD55, IDO1, LCN2, NOS2, CCL11, OLFM4, ANXA1, REG1A, S100A9, SLPI, SPINK1, and AGR2 were significantly higher. Functional enrichment analysis showed that DEGs were closely related to immune and inflammatory responses, which in turn are related to many challenges in the diagnosis and treatment of UC. Mechanistically, APA site selection was found to contribute to the regulation of gene expression in UC, and some APA genes were identified as potential regulators of miRNAs and RBPs. Vene diagram revealed significant overlap between miRNA- and RBP-targeted genes and DEGs, suggesting that APA genes may modulate genes expression in UC through miRNA and RBP targeting. Additionally, five key APA genes--CD38, NCALD, SMIM31, GPX7, and SWAP70--were identified as potentially playing crucial role in UC pathogenesis.

This study provides new insights into the molecular mechanisms of UC through ONT-RNA-seq technology, especially in gene expression regulation and APA site selection.