Exploration of microRNAs in porcine milk exosomes

Abstract

BackgroundBreast milk contains complex nutrients and facilitates the maturation of various biological systems in infants. Exosomes, membranous vesicles of endocytic origin found in different body fluids such as milk, can mediate intercellular communication. We hypothesized that microRNAs (miRNAs), a class of non-coding small RNAs of 18–25 nt which are known to be packaged in exosomes of human, bovine and porcine milk, may play important roles in the development of piglets.ResultsIn this study, exosomes of approximately 100 nm in diameter were isolated from porcine milk through serial centrifugation and ultracentrifugation procedures. Total RNA was extracted from exosomes, and 5S ribosomal RNA was found to be the major RNA component. Solexa sequencing showed a total of 491 miRNAs, including 176 known miRNAs and 315 novel mature miRNAs (representing 366 pre-miRNAs), which were distributed among 30 clusters and 35 families, and two predicted novel miRNAs were verified targeting 3’UTR of IGF-1R by luciferase assay. Interestingly, we observed that three miRNAs (ssc-let-7e, ssc-miR-27a, and ssc-miR-30a) could be generated from miRNA-offset RNAs (moRNAs). The top 10 miRNAs accounted for 74.5% (67,154 counts) of total counts, which were predicted to target 2,333 genes by RNAhybrid software. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses using DAVID bioinformatics resources indicated that the identified miRNAs targeted genes enriched in transcription, immunity and metabolism processes, and 14 of the top 20 miRNAs possibly participate in regulation of the IgA immune network.ConclusionsOur findings suggest that porcine milk exosomes contain a large number of miRNAs, which potentially play an important role in information transfer from sow milk to piglets. The predicted miRNAs of porcine milk exosomes in this study provide a basis for future biochemical and biophysical function studies.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-100) contains supplementary material, which is available to authorized users.

No effect of an elevated miR-30b level in mouse milk on its level in pup tissues

“…Recent studies have shown that immune-related microRNAs are present and enriched in milk [18][19][20][21] suggesting that microRNAs in breast milk may affect development of the immune system, although at present there is no evidence to support these hypotheses.…”

Revelation of mRNAs and proteins in porcine milk exosomes by transcriptomic and proteomic analysis

“…The real-time PCR thermal profile was as follows: 5 min at 95 °C, 40 cycles of 30 s at 94 °C, 30 s at the corresponding annealing temperature (Tm) and 72 °C for 30 s, followed by 72 °C at 10 min, and 5S ribosomal RNA was used as an internal control for the PCR [17, 34]. The mRNAs primers were designed with Primer 5.0 (Table 1).…”

miR-1343 attenuates pathways of fibrosis by targeting the TGF-β receptors

“…miR-1343 was identified in several small RNA-sequencing (RNA-seq) studies in humans [27,28], cows [29] and pigs [30,31], although it remains uncharacterized. It is not documented in rodents, suggesting low conservation through evolution.…”