Zhao Xue-Qiang, Zhu Le-Le, Chang Qing, Jiang Changying, You Yun, Luo Tianming, Jia Xin-Ming, Lin Xin
From the Departments of Molecular and Cellular Oncology, and Immunology, The University of Texas, MD Anderson Cancer Center, Houston, Texas 77030.
the Department of Immunology, School of Medicine, Tongji University, Shanghai 200092, China, and.
J Biol Chem. 2014 Oct 24;289(43):30052-62. doi: 10.1074/jbc.M114.588574. Epub 2014 Sep 8.
Previous studies indicate that both Dectin-3 (also called MCL or Clec4d) and Mincle (also called Clec4e), two C-type lectin receptors, can recognize trehalose 6,6'-dimycolate (TDM), a cell wall component from mycobacteria, and induce potent innate immune responses. Interestingly, stimulation of Dectin-3 by TDM can also induce Mincle expression, which may enhance the host innate immune system to sense Mycobacterium infection. However, the mechanism by which Dectin-3 induces Mincle expression is not fully defined. Here, we show that TDM-induced Mincle expression is dependent on Dectin-3-mediated NF-κB, but not nuclear factor of activated T-cells (NFAT), activation, and Dectin-3 induces NF-κB activation through the CARD9-BCL10-MALT1 complex. We found that bone marrow-derived macrophages from Dectin-3-deficient mice were severely defective in the induction of Mincle expression in response to TDM stimulation. This defect is correlated with the failure of TDM-induced NF-κB activation in Dectin-3-deficient bone marrow-derived macrophages. Consistently, inhibition of NF-κB, but not NFAT, impaired TDM-induced Mincle expression, whereas NF-κB, but not NFAT, binds to the Mincle promoter. Dectin-3-mediated NF-κB activation is dependent on the CARD9-Bcl10-MALT1 complex. Finally, mice deficient for Dectin-3 or CARD9 produced much less proinflammatory cytokines and keyhole limpet hemocyanin (KLH)-specific antibodies after immunization with an adjuvant containing TDM. Overall, this study provides the mechanism by which Dectin-3 induces Mincle expression in response to Mycobacterium infection, which will have significant impact to improve adjuvant and design vaccine for antimicrobial infection.
先前的研究表明，两种C型凝集素受体——小甘露糖受体3（也称为MCL或Clec4d）和小甘露糖受体（也称为Clec4e），都能识别海藻糖6,6'-二霉菌酸酯（TDM），一种来自分枝杆菌的细胞壁成分，并诱导强烈的先天性免疫反应。有趣的是，TDM对小甘露糖受体3的刺激也能诱导小甘露糖受体的表达，这可能会增强宿主的先天性免疫系统以感知分枝杆菌感染。然而，小甘露糖受体3诱导小甘露糖受体表达的机制尚未完全明确。在此，我们表明TDM诱导的小甘露糖受体表达依赖于小甘露糖受体3介导的核因子κB（NF-κB）激活，而非活化T细胞的核因子（NFAT）激活，并且小甘露糖受体3通过CARD9-BCL10-MALT1复合物诱导NF-κB激活。我们发现，来自小甘露糖受体3缺陷小鼠的骨髓来源巨噬细胞在响应TDM刺激时诱导小甘露糖受体表达方面存在严重缺陷。这种缺陷与TDM诱导的小甘露糖受体3缺陷骨髓来源巨噬细胞中NF-κB激活失败相关。一致地，抑制NF-κB而非NFAT会损害TDM诱导的小甘露糖受体表达，而NF-κB而非NFAT与小甘露糖受体启动子结合。小甘露糖受体3介导的NF-κB激活依赖于CARD9-Bcl10-MALT1复合物。最后，用含TDM的佐剂免疫后，小甘露糖受体3或CARD9缺陷的小鼠产生的促炎细胞因子和钥孔戚血蓝蛋白（KLH）特异性抗体要少得多。总体而言，本研究提供了小甘露糖受体3响应分枝杆菌感染诱导小甘露糖受体表达的机制，这将对改进佐剂和设计抗微生物感染疫苗产生重大影响。
