Release of TNF-α from macrophages is mediated by small GTPase Rab37
Release of TNF-α from macrophages is mediated by small GTPase Rab37
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DOI：
10.1002/eji.201141640
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发表时间：
2011-11-01
影响因子：
5.4
通讯作者：
Tsuboi, Takashi
中科院分区：
文献类型：
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作者：
Mori, Ryoichi;Ikematsu, Kazuya;Tsuboi, Takashi
伤口部位的活化巨噬细胞释放许多细胞因子，这些细胞因子积极影响皮肤伤口愈合。然而，控制巨噬细胞分泌细胞因子的分子机制尚未阐明。在本研究中，我们进行了RT-PCR分析，发现19个小的GTTRab同种型在皮肤伤口部位表达，其中6个（即Rab 3B，Rab 27 B，Rab 30，Rab 33 A，Rab 37和Rab 40 C）在皮肤修复的炎症和增殖/迁移阶段上调。我们还发现，小鼠原代和RAW264.7巨噬细胞中Rab 37的基因表达在LPS刺激后被显著诱导。RAW264.7细胞中野生型和组成型活性Rab 37的过表达显著增加TNF-α的分泌，而通过siRNA敲低Rab 37则显著降低TNF-α的分泌。我们还利用液相色谱/线性离子阱质谱（LC-MS/MS）鉴定了29个推定的Rab 37相互作用蛋白，包括调节Munc 13 -1的膜融合蛋白。免疫细胞化学分析进一步揭示，在活化的巨噬细胞中，含有TNF-α的囊泡与Rab 37和Munc 13 -1共定位。通过siRNA敲低Munc 13 -1显著降低TNF-α分泌。总之，这些发现表明Rab 37与Munc 13 -1相互作用以控制活化的巨噬细胞的TNF-α分泌。
Activated macrophages at wound sites release many cytokines which positively affect skin wound healing. However, the molecular mechanisms controlling cytokine secretion from macrophages have not been elucidated. In the present study, we performed an RT-PCR analysis and found that 19 small GTPase Rab isoforms were expressed at skin wound sites, with six of them (i.e. Rab3B, Rab27B, Rab30, Rab33A, Rab37, and Rab40C) being upregulated during the inflammation and proliferation/migration phase of skin repair. We also found that gene expression of Rab37 in murine primary and RAW264.7 macrophages was significantly induced after stimulation with LPS. Overexpression of wild type and constitutively active Rab37 in RAW264.7 cells significantly increased TNF-alpha secretion, whereas knockdown of Rab37 by siRNA significantly decreased it. We also identified 29 putative Rab37-interacting proteins, including the membrane fusion regulating Munc13-1, using liquid chromatography/linear ion trap mass spectrometry (LC-MS/MS). Immunocytochemical analysis further revealed that TNF-alpha-containing vesicles were colocalized with both Rab37 and Munc13-1 in activated macrophages. Knockdown of Munc13-1 by siRNA significantly decreased TNF-alpha secretion. Taken together, these findings demonstrate that Rab37 interacts with Munc13-1 to control TNF-alpha secretion from activated macrophages.