MicroRNAomes of cattle intestinal tissues revealed possible miRNA regulated mechanisms involved in Escherichia coli O157 fecal shedding

The current study aimed to investigate whether bovine non-coding RNA play a role in regulating E. coli O157 shedding through studying miRNAomes of the whole gastrointestinal tract including duodenum, proximal jejunum, distal jejunum, cecum, spiral colon, descending colon and rectum. The number of miRNAs detected in each intestinal region ranged from 390 ± 13 to 413 ± 49. Compared between SS and NS, the number of differentially expressed (DE) miRNAs ranged from one to eight, and through the whole gut, seven miRNAs were up-regulated and seven were down-regulated in SS. The distal jejunum and rectum were the regions where the most DE miRNAs were identified (8 and 7, respectively). Functional analysis indicated that the bta-miR-378b, bta-miR-2284j and bta-miR-2284d which were down-regulated in both distal jejunum and rectum of SS, the bta-miR-2887 which was down-regulated in rectum of SS, as well as the bta-miR-211 and bta-miR-29d-3p which were up-regulated in rectum of SS were potentially regulatory to host immune functions, including hematological system development and immune cell trafficking. Our findings suggest that the alternation of miRNA expression in the gut of SS may lead to differential regulation in immune functions involved in E. coli O157 super-shedding in cattle. Overall design: We performed a differential analysis of microRNA expression of intestinal tissues collected from E. coli O157 super-shedders and non-shedders, targets prediction for interested microRNAs, and functional analysis for interested microRNAs, to study molecular mechanisms of super-shedding phenomenon.