AIM:To explore the regulatory effect of chemokine CCL 3 on exosome secretion from human bone marrow mesenchymal stem cells(hBMSCs).METHODS: hBMSCs were stimulated with chemokine CCL 3 at different concentrations in vitro.The proliferation of hBMSCs was measured by CCK-8 assay and viable cell counting.Exosome se-cretion from hBMSCs was qualitatively analyzed by transmission electron microscope(TEM)and flow cytometry, and the quantitative analysis was carried out by flow cytometry and nanoparticle tracking analysis(NTA).RESULTS:Compared with control group,the viability of the hBMSCs detected by CCK-8 assay was increased when hBMSCs were treated with CCL3(P<0.05).The results of viable cell counting demonstrated that the number of hBMSCs was raised in CCL 3 group in a dose-dependent manner(P<0.05).The results of flow cytometry showed that hBMSCs expressed 3 CCL3-related spe-cific receptors,CCR1,CCR5 and CCR9.Compared with control group,the fluorescence intensity of CCR9 in CCL3 group was obviously enhanced.However,no significant difference of fluorescence intensity for CCR 5 and CCR1 was observed be-tween the 2 groups.The results of NTA demonstrated that the secretion capacity of CCL 3-induced hBMSCs was far less than that in control group(P<0.05).However, the microvesicles larger than 100 nm in CCL3 groups were increased(P<0.05).The above results indicated that the higher concentration of CCL 3 induced the lower secretion of exosomes.In addi-tion,the results of flow cytometry demonstrated that CCL 3-induced hBMSCs showed lower quantity of CD 9 +exosomes than those in control group(P<0.01).CONCLUSION:CCL3 promotes the proliferation of hBMSCs but depresses the secre-tion of exosomes in a dose-dependent manner.CCL3 affects the size distribution of exosomes and increases the number of nonfunctional microvesicles of larger than 100 nm in size.CCL3 induces the expression of CCR9 in hBMSCs.%目的:探讨趋化因子CCL3对人骨髓间充质干细胞(human bone marrow mesenchymal stem cells, hBMSCs)外泌体分泌的调控作用.方法:采用CCK-8法和活细胞计数检测hBMSCs的增殖活性;采用电镜观察、流式细胞术和纳米颗粒跟踪分析(nanoparticle tracking analysis,NTA)对外泌体进行定性和定量分析.结果:CCK-8检测显示,CCL3组细胞的存活率大于对照组(P<0.05);活细胞计数结果显示,CCL3组细胞数明显多于对照组(P<0.05),呈浓度依赖性;流式细胞术分析结果显示,hBMSCs表达CCR1、CCR5和CCR93种CCL3特异性受体;CCL3作用hBMSCs后,CCR9荧光强度明显增强,CCR5和CCR1荧光强度无显著差异.NTA结果显示,与对照组相比, CCL3组外泌体分泌量明显减小(P<0.05),同时微囊泡(粒径大于100 nm)数明显增多(P<0.05);外泌体流式细胞术分析结果提示,与对照组相比,CCL3组的CD9 +外泌体阳性率显著下降(P<0.01).结论:CCL3促进hBMSCs增殖并抑制其外泌体的分泌,同时影响hBMSCs外泌体的粒径分布,无效的微囊泡增多.
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