Comparative Study of the Expression Profiles of miRNAs of Milk-Derived Exosomes of Yak and Jeryak

Abstract

The Jeryak is the hybrid offspring of yaks and Jersey cattle and exhibit improved milk and meat yields. Biomolecules carried within milk exosomes are important for cell growth, development, immune regulation, and various pathophysiological processes. Previous studies showed that miRNAs regulate mammary gland development, lactation, and milk quality. This study explored the relationship between milk exosomes miRNAs and lactation performance. A comparison of the milk content showed that yak milk was of a better quality compared to Jeryak milk (casein, fat, TS, SNF, lactose). Milk collected in December was superior to that collected in June for both yak and Jeryak, except for lactose concentrations. Exosomes were extracted by density gradient centrifugation and miRNA expression profiles in milk exosomes from three yaks and three Jeryaks collected in June and December were detected by small RNA sequencing. In all, 22, 120, 78, and 62 differentially expressed miRNAs (DEMs) were identified in Jun_ JY vs. Jun_ Y (P1: Jeryak in June vs. Yak in June), Jun_ JY vs. Dec_ JY (P2: Jeryak in June vs. Jeryak in December), Dec_ JY vs. Dec_ Y (P3: Jeryak in December vs. Yak in December), and Jun_ Y vs. Dec_ Y (P4: Yak in June vs. Yak in December) groups. These DEMs were enriched in functions and signaling pathways related to lactation performance. In conclusion, these findings are a reference tool to study the molecular basis of lactation performance.

Bovine Colostrum miR-30a-5p Targets the NF-κB Signaling Pathway to Alleviate Inflammation in Intestinal Epithelial Cells

“…Researchers have identified more than 1500 different miRNAs in bovine milk exosomes, with miR-148a, miR-30, miR-146, miR-200, miR-21, let-7, and others being common . The number and types of exosomal miRNAs in milk also change dynamically according to the breed of animals, lactation period, external environment, and seasonal changes . Although the biological functions of milk-derived miRNAs have not been fully confirmed; however, analysis by bioinformatic techniques predicts that most of them are involved in processes such as signal transduction, cell proliferation, and differentiation .…”

“…9 The number and types of exosomal miRNAs in milk also change dynamically according to the breed of animals, 10 lactation period, 11 external environment, 12 and seasonal changes. 13 Although the biological functions of milk- derived miRNAs have not been fully confirmed; however, analysis by bioinformatic techniques predicts that most of them are involved in processes such as signal transduction, cell proliferation, and differentiation. 14 Studies have now begun to investigate the role of exogenous miRNAs carried by milkderived exosomes in regulating intestinal mucosal immune homeostasis across borders.…”

ДНК МАРКЕРЫ И «МИКРОСАТЕЛЛИТНЫЙ КОД» (Обзор)

“…The problem is that one miRNA can be involved in the control of hundreds of genes, so functional validation of each target gene for this miRNA is difficult. The situation is further complicated by the fact that the response to the same environmental factors can be provided by different microRNAs, not only in closely related species [39], but also in breeds [40].…”

“…MicroRNAs as elements of regulatory networks have attracted attention due to their involvement in the control and modulation of the functional activity of genes [37][38][39][40]. However, it must be taken into account that the degree of variability in the expression level of different genes is not the same.…”

“…Thus, although the role of microRNAs in regulatory networks is indisputable (as is the role of the regulatory networks themselves in the formation of traits and changes in their manifestations under the influence of influencing factors), the promise of microRNAs as molecular markers is ambiguous. As noted above, one microRNA can affect the transcripts of several dozen genes, and different microRNAs can affect the activity of one gene [37][38][39][40]. Thousands of transcription regulatory factors also change it by interacting with non-coding nucleotide sequences of the gene [40,41].…”