CCL3 promotes hBMSC proliferation and inhibits exosome secretion / 中国病理生理杂志

ABSTRACT

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.