Toxoplasma gondii rhoptry kinase ROP16 activates STAT3 and STAT6 resulting in cytokine inhibition and arginase-1-dependent growth control.
Toxoplasma gondii rhoptry kinase ROP16 activates STAT3 and STAT6 resulting in cytokine inhibition and arginase-1-dependent growth control.
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DOI：
10.1371/journal.ppat.1002236
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发表时间：
2011-09
期刊：
影响因子：
6.7
通讯作者：
Denkers EY
中科院分区：
文献类型：
--
作者：
Butcher BA;Fox BA;Rommereim LM;Kim SG;Maurer KJ;Yarovinsky F;Herbert DR;Bzik DJ;Denkers EY
弓形虫的ROP 16激酶被注射到宿主细胞胞质溶胶中，在那里它激活信号转导和转录激活因子（STAT）-3和STAT 6。在此，我们在I型寄生虫菌株背景上产生了ROP 16缺失突变体，以及具有恢复的ROP 16表达的对照互补突变体。我们研究了ROP 16分子在T.弓形虫感染用rop 16缺失（Δ ROP 16）寄生虫感染小鼠骨髓源性巨噬细胞，导致IL-12 p40产生量相对于ROP 16阳性RH亲本菌株增加。在Δ ROP 16感染中，高水平的IL-12 p40产生依赖于宿主细胞衔接分子MyD 88，但令人惊讶的是，它不依赖于任何先前识别的T.与MyD 88（TLR 2、TLR 4、TLR 9、TLR 11、IL-1 β和IL-18）连接的弓形虫触发通路。此外，发现ROP 16介导弓形虫对LPS诱导的巨噬细胞中的细胞因子合成以及对星形胶质细胞和小胶质细胞的IFN-γ诱导的一氧化氮产生的抑制作用。此外，R 0 P16以STAT 6依赖性方式触发宿主细胞辅酶A酶-1的合成。在成纤维细胞和巨噬细胞中，Δ ROP 16速殖子未能诱导精氨酸酶-1导致对限制精氨酸的饥饿条件的抗性，精氨酸是该寄生虫复制和毒力的必需氨基酸。在体内感染过程中，不能诱导宿主细胞增殖酶-1的Δ ROP 16速殖子表现出复制和传播增加。我们的结论是，弓形虫ROP 16和宿主细胞STAT信号级联之间的遭遇具有多效性的下游效应，其以多种复杂的方式起作用以指导感染过程。 刚地弓形虫是一种分布极为广泛的细胞内原生动物寄生虫，在人类和动物中建立持久的感染。由于弓形虫感染通常是无症状的，很明显，这种寄生虫已经发展了复杂的方法来操纵宿主免疫力。最近，寄生虫ROP 16激酶被鉴定为宿主细胞信号传导的重要决定因素。在细胞侵入期间，ROP 16被注射到宿主细胞的细胞质中，随后定位于细胞核。在这里，我们报告了ROP 16敲除寄生虫（Δ ROP 16）以及Δ ROP 16互补突变体（Δ ROP 16：1）的产生，并描述了删除和重新插入该分子的生物学效应。我们发现ROP 16控制激活多种宿主细胞信号通路的能力，同时抑制巨噬细胞促炎反应。ROP 16的缺失增加了寄生虫在体内感染期间复制和传播的能力。这种增加的生长反应可能是由R 0 P16依赖性激活宿主细胞凋亡酶-1引起的。精氨酸酶-1的诱导限制了精氨酸的可用性，精氨酸是寄生虫生长和宿主诱导的一氧化氮产生所需的氨基酸。我们的研究结果提供了新的见解细胞内真核病原体和其宿主细胞之间的复杂的相互作用。
The ROP16 kinase of Toxoplasma gondii is injected into the host cell cytosol where it activates signal transducer and activator of transcription (STAT)-3 and STAT6. Here, we generated a ROP16 deletion mutant on a Type I parasite strain background, as well as a control complementation mutant with restored ROP16 expression. We investigated the biological role of the ROP16 molecule during T. gondii infection. Infection of mouse bone marrow-derived macrophages with rop16-deleted (ΔROP16) parasites resulted in increased amounts of IL-12p40 production relative to the ROP16-positive RH parental strain. High level IL-12p40 production in ΔROP16 infection was dependent on the host cell adaptor molecule MyD88, but surprisingly was independent of any previously recognized T. gondii triggered pathway linking to MyD88 (TLR2, TLR4, TLR9, TLR11, IL-1ß and IL-18). In addition, ROP16 was found to mediate the suppressive effects of Toxoplasma on LPS-induced cytokine synthesis in macrophages and on IFN-γ-induced nitric oxide production by astrocytes and microglial cells. Furthermore, ROP16 triggered synthesis of host cell arginase-1 in a STAT6-dependent manner. In fibroblasts and macrophages, failure to induce arginase-1 by ΔROP16 tachyzoites resulted in resistance to starvation conditions of limiting arginine, an essential amino acid for replication and virulence of this parasite. ΔROP16 tachyzoites that failed to induce host cell arginase-1 displayed increased replication and dissemination during in vivo infection. We conclude that encounter between Toxoplasma ROP16 and the host cell STAT signaling cascade has pleiotropic downstream effects that act in multiple and complex ways to direct the course of infection. Toxoplasma gondii is an extremely widespread intracellular protozoan parasite that establishes long-lasting infection in humans and animals. Because Toxoplasma infection is most often asymptomatic, it is evident that this parasite has developed sophisticated ways to manipulate host immunity. Recently, the parasite ROP16 kinase was identified as an important determinant of host cell signaling. During cell invasion, ROP16 is injected into the host cell cytoplasm and subsequently localizes to the nucleus. Here, we report the generation of ROP16 knockout parasites (ΔROP16) as well as ΔROP16 complementation mutants (ΔROP16:1) and we describe the biological effects of deleting and re-inserting this molecule. We find that ROP16 controls the ability to activate multiple host cell signaling pathways and simultaneously suppress macrophage proinflammatory responses. Deletion of ROP16 increases parasite ability to replicate and disseminate during in vivo infection. This increased growth response may arise from ROP16-dependent activation of host arginase-1. Induction of arginase-1 limits availability of arginine, an amino acid that is required for parasite growth and host-inducible nitric oxide production. Our results provide new insight into the complex interactions between an intracellular eukaryotic pathogen and its host cell.
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影响因子：
32.4
作者：
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4.4
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通讯作者：
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通讯作者：
Denkers, EY