ETH Zurich, Animal Physiology, Institute of Agricultural Sciences, 8092 Zurich, Switzerland.
Int J Mol Sci. 2023 Jun 16;24(12):10210. doi: 10.3390/ijms241210210.
Extracellular vesicles (EVs) and their microRNA (miRNA) cargo have been proposed as possible mammary gland health biomarkers in cattle. However, throughout the day, the biologically active milk components, such as miRNAs, may change due to the dynamic nature of milk. The current study aimed to evaluate the circadian fluctuation of milk EVs miRNA cargo to assess the feasibility of milk EVs as future biomarkers for mammary gland health management. Milk from four healthy dairy cows was collected for four consecutive days in the two daily milking sessions in the morning and the evening. The isolated EVs were heterogeneous, intact, and carried the EV protein markers CD9, CD81, and TSG101, as shown by transmission electron microscopy and western blot. The miRNA sequencing results demonstrate that the abundance of miRNA cargo in milk EVs remained stable, unlike other milk components, such as somatic cells, that changed during milking sessions. These findings indicated that the miRNA cargo within milk EVs remains stable irrespective of the time of day, suggesting their potential utility as diagnostic markers for mammary gland health.
细胞外囊泡（EVs）及其携带的 microRNA（miRNA）已被提出作为牛乳腺健康的生物标志物。然而，由于牛奶的动态性质，生物活性的牛奶成分，如 miRNA，可能会在一天中发生变化。本研究旨在评估牛奶 EVs miRNA 货物的昼夜波动，以评估牛奶 EVs 作为未来乳腺健康管理生物标志物的可行性。从四头健康奶牛的牛奶中连续四天在早晚两次挤奶中采集。通过透射电子显微镜和 Western blot 分析，所分离的 EVs 表现出异质性、完整性，并携带 EV 蛋白标志物 CD9、CD81 和 TSG101。miRNA 测序结果表明，与其他牛奶成分（如体细胞）不同，牛奶 EVs 中的 miRNA 货物丰度保持稳定。这些发现表明，无论一天中的时间如何，牛奶 EVs 中的 miRNA 货物都保持稳定，这表明它们可能作为乳腺健康的诊断标志物具有潜在的应用价值。
