Developmental Alterations of Colonic microRNA Profiles Imply Potential Biological Functions in Kid Goats

SIMPLE SUMMARY: The colon plays a crucial role in the fermentation and utilization of cell wall carbohydrates, cellulose, and hemicellulose in ruminants. MicroRNAs have been reported to be involved in regulating the gastrointestinal development and maintaining intestinal homeostasis of mammals. In this study, we first reveal the microRNA expression profiles in the colon of kid goats. Meanwhile, we found that targeted genes of DEmiRNAs were highly enriched for the prevention of microbial invasion via the Erbb−MAPK network while targeted genes of HEmiRNAs contributed to the permeable barrier maintenance and surveillance of cell damage. Additionally, more than half of the microRNAs showed a developmentally dynamic expression in the colon of kid goats. This study disclosed microRNA-based biological functions in the regulation of colon development in ruminants. ABSTRACT: The colon is a crucial digestive organ of the hind gut in ruminants. The bacterial diversity and mucosal immune maturation in this region are related to age. However, whether the microRNA expression in the colon of goats is affected by age is still unclear. In the current study, we analyzed the transcriptomes of colon microRNAs during preweaning (Day 10 and Day 25) and postweaning (Day 31). A total of 1572 microRNAs were identified in the colon tissues. Of these, 39 differentially expressed microRNAs (DEmiRNAs) and 88 highly expressed microRNAs (HEmiRNAs) were screened. The target genes regulated by the DEmiRNAs and HEmiRNAs were commonly enriched in the MAPK signaling pathway, Wnt signaling pathway, Hippo signaling pathway, cell adhesion molecules, focal adhesion, and adherens junction. Remarkably, the targeted genes of the DEmiRNAs were highly enriched for the prevention of microbial invasion via the Erbb−MAPK network while the targeted genes of HEmiRNAs contributed to the permeable barrier maintenance and cell damage surveillance. Additionally, there were eight different expression profiles of 87 dynamic miRNAs, in which approximately half of them were affected by age. Taken together, our study reveals the different roles of DEmiRNAs, HEmiRNAs, and dynamic microRNAs in the development of the colon and gives new insights into the regulatory mechanism of colon development in goats.