转化生长因子-β1以浓度依赖的方式重组人成熟树突状细胞的细胞骨架丝状肌动蛋白

Reconstruction of cytoskeleton filament actin of human mature dendritic cells by transforming growth factor-β1 in a concentration-dependent manner

摘要:

目的：探索转化生长因子β1（tansforming growth factor-β1，TGF-β1）对人成熟树突状细胞（mature dendritic cells，mDCs）骨架丝状肌动蛋白（filament actin，F-actin）及其部分骨架结合蛋白表达的影响，为深入理解树突状细胞（dendritic cells，DCs）的生物学行为和提高基于DCs的抗肿瘤免疫治疗的临床效率提供线索。方法：不同浓度的TGF-β1处理mDCs后，用激光共聚焦显微镜和免疫印迹实验分别研究细胞骨架F-actin的结构和部分细胞骨架结合蛋白表达水平的变化。结果：（1）与对照组相比，TGF-β1处理后的mDCs的F-actin出现了明显重排，F-actin的表达量在3 ng/ml组下调（P=0.000），在5 ng/ml组上调（P=0.000）。（2）mDCs表面丝状突起长度和数量的变化，长度在3 ng/ml和5 ng/ml组较对照组细、短（P=0.001，0.000）；数量在1、3 ng/ml和5 ng/ml组较对照组少而稀疏（P=0.000）；在7 ng/ml组mDCs表面丝状突起长度和数量的变化均无统计学意义（P=0.114）；通过回归分析细胞丝状突起长度和数量与F-actin表达量之间存在非线性相关性（R2分别为0.828和0.746，P=0.000）。（3）细胞骨架蛋白结合蛋白的表达，fascin1在所有实验组中均出现了下调（P=0.001、0.000）；p-cofilin1与总cofilin1的表达水平比在1 ng/ml和3 ng/ml组均下调（P=0.000）；profilin的表达在1、3 ng/ml和5 ng/ml组均上调（P=0.001、0.001、0.013）。结论：TGF-β1以浓度依赖的方式影响mDCs的细胞骨架F-actin结构及其部分结合蛋白的表达，提示在临床上施行基于DCs的抗肿瘤免疫治疗时，需以适当的方式阻断TGF-β1的信号转导通路，这对进一步深入理解DCs的生物学行为和肿瘤的免疫逃逸机制具有重要意义。

Abstract:

Objective：To explore the effects of transforming growth factor-β1（TGF-β1） on the cytoskeleton filament actin（F-actin） and expression of some binding proteins in mature dendritic cells（mDCs） in order to further understand the biological behaviors and find the clue of improving the clinical efficiency of DCs-based therapy against cancer. Methods：mDCs were treated with different concentrations of TGF-β1 and the organization of cytoskeleton F-actin and expression of some cytoskeleton-binding proteins were respectively observed and measured by laser confocal microscopy and Western blot. Results：（1）F-actin organization was reconstructed in mDCs treated with various concentrations of TGF-β1 compared with that in control group. F-actin expression quantity in 3 ng/ml group was significantly down-regulated（P=0.000） and expres－sion quantity of F-actin in 5 ng/ml group was significantly up-regulated（P=0.000）. （2）Length of cell membrane protrusions in 3 ng/ml and 5 ng/ml group was thinner and shorter than that in control group（P=0.001，0.000）. Number of cell membrane pro－trusions in 1，3，5 ng/ml groups was sparser than that in control group（P=0.000）. Non-liner correlation between expression of F-actin and characteristics of cell membrane protrusion（length and number） was observed（R2=0.828，0.746 respectively，P=0.000）. （3）Expression of cytoskeleton-binding proteins and expression quantity of F-actin in all groups was significantly down-regulated（P=0.001，0.000）. Phosphorylation of cofilin1 in 1 ng/ml and 3 ng/ml group was significantly down-regulated（P=0.000，0.000）. Expression quantity of profilin in 1，3，5 ng/ml group was significantly up-regulated（P=0.001，0.001，0.013）. Conclusions：Organization of cytoskeleton F-actin and some of its binding proteins in mDCs are affected by TGF-β1 in a concentration-dependent manner，indicating that the signal pathway of TGF-β1 should be blocked in appropriate way before performing DCs-based im－munotherapy against cancer. It’s of great significance to understand the biological behaviors and immune escape mechanism of tumor.