Institute of Animal Science/Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
Youyuan Research Institute of Dairy Industry Co., Ltd, Nanjing, 211100, China.
Mol Biol Rep. 2022 Oct;49(10):9297-9305. doi: 10.1007/s11033-022-07767-6. Epub 2022 Aug 9.
Exosomes are involved in intercellular communication, affecting many physiological and pathological process. The present study evaluated the effects of serum exosomes on the function of bovine mammary epithelial cells (BMECs) and milk synthesis under heat stress.
We cultured the BMECs in fetal bovine serum (FBS) or exosome-free FBS medium and examined, their viability using CCK-8 kit. The results showed that culturing the cells in an exosome-free medium decreased viability and increased the levels of reactive oxygen species. The BMECs cultured in the exosome-free medium had reduced mitochondrial membrane potential, decreased manganese superoxide dismutase activity, and disrupted mitochondrial dynamics. They exhibited apoptosis due to upregulated Drp1, Fis1, Bax and HSP70. Lastly, we observed downregulation of milk fat and lactoprotein-related genes: mTOR, PPARγ, p-mTOR and ADD1 and SREBP1, ELF5, and CSN2, respectively, after culturing the cells in an exosome-free medium. These negative effects of the exosome-free medium on the BMECs could be further reinforced under heat stress.
Our results demonstrated that exosomes from serum are critical for maintaining the normal function of BMECs.
外泌体参与细胞间通讯，影响许多生理和病理过程。本研究评估了血清外泌体在热应激下对牛乳腺上皮细胞（BMEC）功能和乳合成的影响。
我们将 BMEC 分别在含胎牛血清（FBS）或无外泌体 FBS 培养基中培养，并使用 CCK-8 试剂盒检测细胞活力。结果表明，在无外泌体培养基中培养细胞会降低细胞活力并增加活性氧水平。在无外泌体培养基中培养的 BMEC 线粒体膜电位降低，锰超氧化物歧化酶活性降低，线粒体动力学受到破坏。由于 Drp1、Fis1、Bax 和 HSP70 的上调，细胞发生凋亡。最后，我们观察到在无外泌体培养基中培养的细胞中，乳脂肪和乳蛋白相关基因 mTOR、PPARγ、p-mTOR 和 ADD1 以及 SREBP1、ELF5 和 CSN2 的表达下调。无外泌体培养基对 BMEC 的这些负面影响在热应激下进一步增强。
我们的结果表明，血清中的外泌体对于维持 BMEC 的正常功能至关重要。
