Characterization of Sheep Milk Extracellular Vesicle-miRNA by Sequencing and Comparison with Cow Milk.

Suyu Quan,Benhai Xiong,Junhu Yao,Xuemei Nan,Linshu Jiang,Kun Wang

doi:10.3390/ani10020331

Abstract

Simple SummaryMilk provides significant health benefits for mammals, especially as the primary nutrient sources of neonates. Milk was recognized as the epigenetic “doping system” during mammalian development in recent research due to the bioactive component extracellular vesicles, which can act as mediators of intercellular communication, and even as signal carriers between different individuals, especially mothers and babies, by the containing regulatory miRNAs. It is widely accepted that although cow milk is generally more consumed by humans, sheep milk is more suitable for infants. However, compared with cow milk, few studies have focused on the sheep milk extracellular vesicles, which select specific types of miRNA to encapsulate. This study clarified the sheep milk extracellular vesicle-miRNA profiling by sequencing and made a comparison with that of cow milk. The results of this study provide more documents for the milk bioactive components in different species.Milk can mediate maternal-neonatal signal transmission by the bioactive component extracellular vesicles (EVs), which select specific types of miRNA to encapsulate. The miRNA profiling of sheep milk EVs was characterized by sequencing and compared with that of cow milk. Nanoparticle tracking analysis revealed that the concentration of sheep milk EVs was 1.3 ± 0.09 × 1012 particles/mL and the diameter was peaked at 131.2 ± 0.84 nm. Sheep milk EVs contained various small RNAs, including tRNA, Cis-regulatory element, rRNA, snRNA, other Rfam RNA, and miRNA, which held about 36% of all the small RNAs. In total, 84 types of miRNA were annotated with Ovis aries by miRBase (version 22.0) in sheep milk EVs, with 75 shared types of miRNAs in all samples. The miR-26a, miR-191, let-7f, let-7b and miR-10b were highly expressed both in cow and sheep milk EVs, and 14 sheep milk EV-miRNAs in the top 20, occupying 98% of the total expression, were immune-related. Although pathway analysis showed different potential functions of cow and sheep milk EV-miRNAs, there were still some shared points: lipid metabolism (phospholipase D, glycerophospholipid and glycosylphosphatidylinositol), calcium metabolism, and nerve conduction (axon guidance and synapse). This study provides reference for the bioactive components in the milk of different species.

Highlights

Milk provides significant health benefits for both humans and other mammals, especially as the primary nutrient sources for mammals before weaning
Milk composition is influenced by many factors, such as species and genetics, lactation stages, environmental conditions, and status
The outputs of ruminant nutrigenomics could benefit the performance of dairy cattle and modify the of pathways whichdemands the milk components maternal mammary milk componentsthrough for the increasing of “healthy”

Summary

Introduction

Milk provides significant health benefits for both humans and other mammals, especially as the primary nutrient sources for mammals before weaning. Milk helps to shape the intestinal microbiome and contributes to the immune maturation and organ development of infants [1]. Milk EVs have been recommended as relatively stable bioactive food compounds in recent research [7]. EVs naturally exist in various bio fluids, such as blood, saliva, urine, amniotic fluid, and milk, and facilitates their regulation of different physiological and pathological intercellular communications [9]. Specific miRNAs exert significant influence on mammalian gene expression and protein synthesis as key regulatory factors, involving in cell cycling, proliferation, and differentiation, programmed cell death, immune activating and sensing nutrient stress [12,13,14]

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