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

Abstract

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.

Ruminant Milk-Derived Extracellular Vesicles: A Nutritional and Therapeutic Opportunity?

“…Several review articles on milk-derived EV nucleic acid cargoes are available, which include their functional implications [ 61 , 163 , 164 ] and future applications [ 165 , 166 ]. Additionally, with development in the application of next-generation sequencing (NGS), several nucleic acid profiling studies (with an emphasis on miRNA) have reported their findings from milk-derived EVs in humans [ 167 , 168 , 169 , 170 , 171 , 172 , 173 ], cows [ 158 , 174 , 175 , 176 , 177 , 178 , 179 ], pigs [ 129 , 170 , 180 , 181 ], sheep [ 182 ], and buffaloes [ 183 ]. In silico insights from these data suggest potential regulation of several key pathways, but for the most part, these predictions have not been validated in vitro or in vivo.…”

“…In silico comparison of the top 20 expressed miRNA in both milks that have immune-related functions. [ 182 ] Exosome Human qPCR, NGS Identified 221 and 48 mature miRNAs (fresh and 4-week-old milk stored at 4 °C, respectively) detected in 1 mL samples. No reliable detection of miRNAs in infant formula.…”

Milk Exosomes: Perspective Agents for Anticancer Drug Delivery

“…Human milk exosomes were first described in 2007. To date, exosomes have been isolated (chronologically) from human [ 5 ], bovine [ 6 ], porcine [ 7 ], wallaby [ 8 ], camel [ 9 ], rat [ 10 ], horse [ 11 ], panda [ 12 ], yak [ 13 ], sheep [ 14 ], and goat milk [ 15 ]. Databases provide more than 100 articles on exosomes and other milk vesicles (more than half of them are on human and cow milk vesicles).…”

Specific and Non-Invasive Fluorescent Labelling of Extracellular Vesicles for Evaluation of Intracellular Processing by Intestinal Epithelial Cells

“…EVs have been identified in human [ 4 , 5 , 6 , 7 ], bovine [ 7 , 8 , 9 ], sheep [ 10 ], camel [ 11 ], and porcine milk [ 12 ]. Additionally, commercial, processed bovine milk has been shown to contain intact EVs with a content of miRNA [ 13 ].…”