次黄嘌呤单核苷酸脱氢酶抑制剂对人外周髓样树突状细胞趋化、迁移和吞噬功能的影响研究

Effect of inosine monophosphate dehydrogenase inhibitor on chemotaxis, migration and endocytosis of human peripheral myeloid dendritic cells

目的探讨次黄嘌呤单核苷酸脱氢酶抑制剂（Inosine monophosphate dehydrogenase inhibitor，IMPDHI）对人外周髓样树突状细胞（Myeloid dendritic cells，MDC）趋化、迁移、吞噬功能的影响。方法新鲜外周血单个核细胞来源于健康志愿者（N=15）。实验组加入不同浓度IMPDHI，流式细胞仪分析MDC表面趋化因子受体表达水平。于transwell小室实验中，加入不同的化学因子，经Lin-1／CD11c／HLA—DR染色后，流式细胞仪计数，以迁移细胞的百分比表示迁移能力。分离树突状细胞抗原-1^＋（Blood dendritic cell antigen-1，BDCA—1^＋）细胞后，以甘露糖受体作为介导，流式细胞仪测定BDCA1^＋细胞中FITC标记的右旋糖酐的荧光值表示吞噬能力。结果（1）趋化、迁移功能：与对照组相比，实验组MDC的趋化因子受体CCR1表达水平明显升高（17．02土3．23～30．63±9．13，P〈0．05）；CCR3表达水平（10．26±2．25～5．81±0．97，P〈0．05）和CCR7表达水平（9．56±1．84～5．18±0．60，P〈0．05）明显下降。实验组MDC对炎性化学因子CCL2、CCL3、CCL4、CCL7、CXCL12的趋化能力明显增强（P〈0．05），对淋巴器官性化学因子CCL19、CCL20、CCL21、CXCL11的趋化能力无明显改变（P〉0．05）。（2）吞噬功能：实验组MDC的吞噬能力明显强于对照组（P〈0．05）。结论IMPDHI增强MDC吞噬抗原的能力，通过提高MDC炎性化学因子受体的表达水平和增强其对炎性化学因子的趋化能力，抑制MDC对淋巴器官的趋化、迁移能力。

Objective To study the effect of inosine monophosphate dehydrogenase inhibitor （IMPDHI） on chemotaxis, migration and endoeytosis of human peripheral myeloid dendritic cells （MDCs）. Methods Freshly isolated peripheral blood mononuelear cells（PBMC）collected from healthy volunteers （N--15） and the study group were treated with IMPDHI. CC chemokine receptors on MDCs were analyzed by flow cytornetry. The study group, control group and different ehemokines were added via trans-well approach for different chemokines, stained by Lin 1/CD11c/HLA-DR and counted by flow eytometry. The migration index was calculated as a percentage of MDC migrated in response to the tested chemokine. After isolation of blood dendritic cell antigen-1^＋ （BDCA-1^＋）, mannose receptor mediated endocytosis was measured as the cellular uptake of FITC dextran by the flow eytometry. Results （1） Compared to the control group, the expression of CCR1 in the study group was up-regulated significantly（ 17.02±3.23 - 30.63 ± 9. 13, P〈0.05 ）and the expressions of CCR3 （10. 26±2. 25-5. 81±0. 97 P〈0.05） and CCR7 （9.56±1.84-5. 18±0.60 P（0.05）were downregulated significantly. MDCs in the study group showed enhanced migratory response to inflammatory chemokine CCL2, CCL3, CCL4, CCL7 and CXCL12 （P〈0.05）. （2）The endocytosis capacity in the study group was significantly higher than that in control group （P〈0.05 ）. Conclusion IMPDHI enhances the endocytotic capacity of MDCs and impairs the migratory response of peripheral MDCs to lymphocytic tissue by up-regulating the expression of chemokine receptor in MDCs and enhancing migratory response to inflammatory chemokines.