title: Potential regulatory role of microRNAs in the development of bovine gastrointestinal tract during early life.
abstract: This study aimed to investigate the potential regulatory role of miRNAs in the development of gastrointestinal tract (GIT) during the early life of dairy calves. Rumen and small intestinal (mid-jejunum and ileum) tissue samples were collected from newborn (30 min after birth; n = 3), 7-day-old (n = 6), 21-day-old (n = 6), and 42-day-old (n = 6) dairy calves. The miRNA profiling was performed using Illumina RNA-sequencing and the temporal and regional differentially expressed miRNAs were further validated using qRT-PCR. Analysis of 16S rRNA gene copy numbers was used to quantify total bacteria, Bifidobacterium and Lactobacillus species. The expression of miR-143 was abundant in all three gut regions, at all time points and it targets genes involved primarily in the proliferation of connective tissue cells and muscle cells, suggesting a role in regulating rapid tissue development during the early life of calves. The expression of miR-146, miR-191, miR-33, miR-7, miR-99/100, miR-486, miR-145, miR-196 and miR-211 displayed significant temporal differences (FDR <0.05), while miR-192/215, miR-194, miR-196, miR-205 and miR-31 revealed significant regional differences (FDR <0.05). The expression levels of miR-15/16, miR-29 and miR-196 were positively correlated with the copy numbers of 16S rRNA gene of Bifidobacterium or Lactobacillus species or both (P<0.05). Functional analysis using Ingenuity Pathway Analysis identified the above mentioned differentially expressed miRNAs as potential regulators of gut tissue cell proliferation and differentiation. The bacterial density-associated miRNAs were identified as modulators of the development of lymphoid tissues (miR-196), maturation of dendritic cells (miR-29) and development of immune cells (miR-15/16). The present study revealed temporal and regional changes in miRNA expression and a correlation between miRNA expression and microbial population in the GIT during the early life, which provides further evidence for another mechanism by which host-microbial interactions play a role in regulating gut development.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Guanxiang
authors.initials: G
authors.lastname: Liang
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Nilusha
authors.initials: N
authors.lastname: Malmuthuge
authors.affiliation: Division of Animal Sciences, University of Missouri, Colombia, Missouri, United States of America.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: McFadden
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Hua
authors.initials: H
authors.lastname: Bao
authors.affiliation: Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Griebel
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Stothard
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Le Luo
authors.initials: le L
authors.lastname: Guan
mesh_terms: D000818:Animals; D002417:Cattle; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D041981:Gastrointestinal Tract / Q000254:growth & development*; D020869:Gene Expression Profiling / Q000379:methods; D035683:MicroRNAs / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017423:Sequence Analysis, RNA / Q000379:methods; D059467:Transcriptome / Q000235:genetics
chemical_list: D035683:MicroRNAs; D012336:RNA, Ribosomal, 16S