Department of Food Science, University of Tennessee , Knoxville, Tennessee, USA.
Immunol Invest. 2020 Oct;49(7):711-725. doi: 10.1080/08820139.2020.1769647. Epub 2020 May 27.
Exosomes are extracellular vesicles involved in intercellular communication. The objectives were to characterize bovine milk exosomes (BME) and determine its effect on RAW 264.7 macrophages.
BME were isolated using differential centrifugation and characterized by particle size and the presence of exosomal markers Alix, TSG101, and CD81. The effect of digestion and different pH on the stability of BME was investigated. The biological activity of BME in RAW 264.7 macrophages was conducted by assessing proliferation and cell cycle. Moreover, the protective effect of exosomes on cisplatin-induced cytotoxicity was evaluated.
BME have an average particle size of 106.8 ± 3.4 nm and expressed Alix, TSG101, and CD81. TSG101 was detected after digestion and exposure to different pH values. Cell-cycle analysis showed that BME reduced the percentage of apoptotic cells while arresting the cells in G2/M phase accompanied by differential expression of proliferation markers p53, p21, cyclin D1, and β-catenin. Exosomes protected macrophages against cisplatin-induced cytotoxicity.
Our results showed for the first time the effect of BME on the proliferation of RAW 264.7 macrophages and its protective effect against chemotherapeutic drug-induced cytotoxicity. Potential effect of BME on immune system must be studied.
外泌体是参与细胞间通讯的细胞外囊泡。本研究的目的是对牛初乳外泌体（BME）进行特征描述，并确定其对 RAW 264.7 巨噬细胞的影响。
采用差速离心法分离 BME，并通过粒径和外泌体标志物 Alix、TSG101 和 CD81 的存在来进行特征描述。研究了消化和不同 pH 值对 BME 稳定性的影响。通过评估 RAW 264.7 巨噬细胞的增殖和细胞周期来研究 BME 的生物活性。此外，还评估了外泌体对顺铂诱导的细胞毒性的保护作用。
BME 的平均粒径为 106.8 ± 3.4nm，并表达了 Alix、TSG101 和 CD81。在消化和暴露于不同 pH 值后检测到 TSG101。细胞周期分析表明，BME 降低了细胞凋亡的百分比，同时将细胞阻滞在 G2/M 期，伴随着增殖标志物 p53、p21、细胞周期蛋白 D1 和β-连环蛋白的差异表达。外泌体保护巨噬细胞免受顺铂诱导的细胞毒性。
我们的研究结果首次表明 BME 对 RAW 264.7 巨噬细胞增殖的影响及其对化疗药物诱导的细胞毒性的保护作用。必须研究 BME 对免疫系统的潜在影响。
