血管内皮细胞生长因子在抗结核免疫中的作用及机制

Role of Vascular Endothelial Growth Factor in Anti-tuberculosis Immunity

【目的】探讨血管内皮细胞生长因子(VEGF)对巨噬细胞抗结核免疫作用的影响。【方法】为了研究VEGF与结核病(TB)之间的相关性,分离健康人和肺结核病人的外周血单核细胞(PBMC),Real-time PCR检测VEGF的表达水平;体外实验中,用卡介苗(BCG)感染佛波酯(PMA)诱导分化的THP-1细胞,PCR检测VEGF的表达水平。进一步探讨VEGF在抗结核免疫中的作用,分别用BCG单独处理或BCG与VEGF共同处理THP-1诱导分化的细胞,Real-time PCR检测促炎因子TNF-α,IL-6,IFN-γ,MIP-2的表达水平;Griess法检测培养上清中一氧化氮(NO)的产生。【结果】肺结核病人的PBMC中VEGF表达水平相对于健康人明显升高。BCG感染THP-1诱导分化的巨噬细胞后,VEGF表达水平上调;VEGF显著增强BCG感染的巨噬细胞中TNF-α,IL-6,IFN-γ,MIP-2的表达和NO的产生。【结论】肺结核病人的PBMC和BCG感染的巨噬细胞中VEGF表达均显著上调,并可能通过影响促炎因子和NO的产生调节巨噬细胞的抗菌活性,提示VEGF可能是治疗结核病的一个靶点。

[ Objective ]To investigate the effect of vascular endothelial growth factor （VEGF） on anti-tuberculosis immune response of macrophage. [ Methods ]To establish the relationship between VEGF and tuberculosis （TB）, real-time PCR was used to determine the expression levels of VEGF in peripheral blood mononuclear cells （PBMC） isolated from TB patients vs healthy individuals. In vitro, phorbol 12-myristate 13-acetate （PMA） was applied to induce THP-1 cells to differentiate into macrophages, and then VEGF mRNA levels were examined by PCR after Bacilil Calmette Guerin （BCG） challenge. To further determine whether VEGF plays a role in TB, THP-1-differentiated macrophages were infected with BCG in the absence or presence of VEGF （ 100 ng/mL）. Expression levels of proinflammatory cytokines including TNF-α, IL-6, IFN-γ and MIP-2 were examined by Real-time PCR, and NO production was measured by Griess Reaction System. [ Results ] VEGF expression levels were significantly up-regulated in PBMC from TB patients vs heahhy individuals. Expression of VEGF was also increased in THP-1-differentiated macrophages challenged by BCG. Interestingly, treatment of VEGF significantly enhanced the induction of TNF-α, IL-6, IFN-γ and MIP-2, as well as the nitric oxide （NO） production in BCG-challenged macrophages. [Conclusion] VEGF were up-regulated in both PBMC isolated from TB patients and macrophages challenged by BCG, and promotes production of proinflammatory cytokines and NO, which are required in the antimicrobial immunity, suggesting that VEGF might be a promising therapeutic target for TB.