Milk microRNA are being studied as a bioactive component of milk. A major fraction of milk microRNA are encapsulated in the lipid bilayered nano-vesicles called exosomes which mediate cell-cell communication. Therefore, the present study was aimed to identify and characterize microRNA in buffalo milk exosomes. Milk exosomes were characterized and used for total RNA isolation. Small RNA sequencing identified 351 microRNA and 17 previously unannotated microRNA in the buffalo milk exosomes. Bta-miR-148a, bta-miR-30a-5p, bta-miR-21-5p, bta-miR-99a-5p, bta-miR-27b, bta-miR-200a, bta-miR-26a, bta-miR-26c, bta-let-7g and bta-let-7i were the 10 most abundant microRNA in buffalo milk exosomes. Out of 5 validated microRNA, bta-miR-148a and −30a-5p were differentially expressed whereas bta-miR-21-5p, bta-miR-200a and bta-let-7g were consistently expressed across lactation stages. Gene targets of the 10 most abundant microRNA were identified using TargetScan taking Homo sapiens as the reference genome. All the targets having context scores < −0.4 with a total of 1539 were taken for network and pathway analysis. In silico analyses predicted 9 significant gene clusters in buffalo milk exosomal microRNA, which were found to be involved in important cellular processes. Analyses of hub genes interactions, string and cytoscape network analysis indicated that ubiquitin proteasomal degradation is the most regulated cellular process by buffalo milk exosomal microRNA. In summary, the repertoire of microRNA identified along with in silico analysis has provided insights into the physiological functionality of bovine milk microRNA in humans.

牛奶microRNA作为牛奶的生物活性成分正在研究中。牛奶microRNA的主要部分封装在称为外泌体的脂质双层纳米囊泡中，介导细胞与细胞之间的通讯。因此，本研究旨在鉴定和表征水牛乳外泌体中的microRNA。对牛奶外泌体进行了表征，并将其用于总RNA分离。小RNA测序在水牛乳外泌体中鉴定出351个microRNA和17个以前未注释的microRNA。Bta-miR-148a，bta-miR-30a-5p，bta-miR-21-5p，bta-miR-99a-5p，bta-miR-27b，bta-miR-200a，bta-miR-26a，bta- miR-26c，bta-let-7g和bta-let-7i是水牛乳外泌体中10种最丰富的microRNA。在5个经过验证的microRNA中，bta-miR-148a和-30a-5p差异表达，而bta-miR-21-5p，bta-miR-200a和bta-let-7g在整个泌乳期始终表达。使用TargetScan鉴定了10个最丰富的microRNA的基因靶标智人作为参考基因组。将上下文得分<-0.4的所有目标（总共1539）用于网络和路径分析。在计算机分析中，预测了水牛乳外泌微RNA中的9个重要基因簇，这些基因簇与重要的细胞过程有关。枢纽基因相互作用，字符串和cytoscape网络分析的分析表明，泛素蛋白酶体降解是水牛乳外泌体microRNA调控最严格的细胞过程。总而言之，鉴定出的微小RNA的组成以及计算机分析已经提供了对人类牛牛奶微小RNA的生理功能的见解。