Granzyme B is a novel interleukin-18 converting enzyme
Granzyme B is a novel interleukin-18 converting enzyme
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DOI：
10.1016/j.jdermsci.2010.05.004
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发表时间：
2010-08-01
影响因子：
4.6
通讯作者：
Mizutani, Hitoshi
中科院分区：
文献类型：
--
作者：
Omoto, Youichi;Yamanaka, Keiichi;Mizutani, Hitoshi
背景：粒酶B（GrB）被认为是诱导细胞凋亡的重要因子，但其在其他生物学事件中的作用尚不清楚。IL-18是一种有效的炎性细胞因子，作为无活性前体（proIL-18）产生。几种细胞，包括单核细胞/巨噬细胞谱系和非造血细胞如角质形成细胞，产生proIL-18。ProIL-18需要适当的处理才能激活。半胱天冬酶-1是真正的IL-18加工酶，并且对于从单核细胞/巨噬细胞谱系细胞释放IL-18是必需的。目的：GrB可以通过穿孔素在非造血细胞的胞浆中侵入并激活，因此我们研究GrB是否能将proIl-18转化为具有生物活性的形式。方法：重组proIl-18产生并纯化（rproIl-18）用于与GrB的蛋白酶反应;通过免疫印迹评估该孵育物。使用KG-1细胞通过IFN-γ测定来确定由GrB切割的蛋白水解片段的生物活性。结果：GrB（+）/caspase-1（-）人CD 8 + T细胞提取物与正常人角质形成细胞（NHK）的proIl-18蛋白酶切片段序列和生物学活性与caspase-1成熟IL-18蛋白酶切片段序列和生物学活性相同。来自CD 8 + T细胞的培养物提取物能够将proIL-18切割成真正的成熟IL-18。结论：GrB是一种有效的IL-18转化酶，提示CTL和/或NK细胞分泌的GrB可启动靶细胞释放IL-18，导致炎症的发生。(C)2010年日本皮肤病研究学会。由Elsevier爱尔兰有限公司出版。保留所有权利。
Background: Granzyme B (GrB) is recognized to induce apoptosis; however, little is known about its possible role in other biological events. IL-18, a potent inflammatory cytokine, is produced as an inactive precursor (proIL-18). Several cells, including monocytes/macrophage lineage and non-hematopoietic cells such as keratinocytes, produce proIL-18. ProIL-18 requires appropriate processing to become active. Caspase-1 is the authentic IL-18 processing enzyme and is essential for IL-18 release from monocyte/macrophage lineage cells. However, caspase-1 is absent in non-hematopoietic cells, suggesting that there is another candidate to cleave proIl-18 except for caspase-1.Objective: GrB can invade and be active in cytoplasm of non-hematopoietic cells via perforin, therefore we investigated whether GrB converts proIl-18 into the biologically active form.Methods: Recombinant proIl-18 (rproIl-18) was produced and purified for protease reaction with GrB; this incubate was evaluated by immunoblotting. Biological activity of the proteolytic fragment cleaved by GrB was determined by IFN-gamma assay using KG-1 cells. IFN-gamma induction was also analyzed between extracts from GrB(+)/caspase-1(-) human CD8+ T cells and proIl-18 from normal human keratinocytes (NHK).Results: The proteolytic fragment that GrB cleaved proIl-18 had the same sequence and biological activity compared with mature IL-18 cleaved by caspase-1. Culture extracts from CD8+ T cells was able to cleave proIl-18 into authentic mature IL-18. IFN-gamma induction was also detected in NHK treated with CD8+ T cells.Conclusion: GrB is a potent IL-18 converting enzyme and suggest that GrB secreted by CTLs and/or NK cells may initiate IL-18 release from target cells, leading to the development of inflammation. (C) 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.