Manipulation of the silkworm immune system by a metalloprotease from the pathogenic bacterium Pseudomonas aeruginosa.
Manipulation of the silkworm immune system by a metalloprotease from the pathogenic bacterium Pseudomonas aeruginosa.
复制标题
病原菌铜绿假单胞菌的金属蛋白酶对家蚕免疫系统的操纵
DOI：
10.1016/j.dci.2018.09.017
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发表时间：
2019-01
影响因子：
2.9
通讯作者：
Lu Z
中科院分区：
文献类型：
--
作者：
Ma L;Zhou L;Lin J;Ji J;Wang Y;Jiang H;Shen X;Lu Z
抗菌肽(AMP)的产生和黑化是昆虫的两种关键体液免疫反应。AMPs的诱导合成是Toll和IMD信号转导的结果，而黑化则依赖于酚氧化酶原(PPO)激活系统。在入侵过程中，病原体产生毒素和其他毒力因子来抵消宿主的免疫反应。在这里，我们发现导致家蚕PPO激活和AMP合成的途径受到铜绿假单胞菌(PAO1)分泌的一种名为弹性蛋白酶B的金属蛋白酶的影响。将PAO1细胞注入家蚕幼虫血腔后不久，金属蛋白水解酶基因(LasB)开始表达，导致弹性蛋白酶活性增加。将纯化的PAO1弹性蛋白酶B注入家蚕血淋巴中，可抑制PPO的活性。相反，这种蛋白酶导致血淋巴中一种AMP--Gloverin的水平增加。用PAO_1ΔlasB突变体感染家蚕，发现感染PAO_1ΔlasB的幼虫血淋巴中PO活性显著高于野生型。突变后的血淋巴具有较低的球蛋白水平和抗菌活性。PAO_1、Δ、lasB在家蚕血淋巴中的存活率降低，而寄主死亡率较低。此外，ΔlasB突变体造成的影响通过互补菌株恢复。这些数据综合表明，PAO1产生的弹性蛋白酶B是一个重要的毒力因子，在感染过程中操纵家蚕的免疫系统。
Antimicrobial peptide (AMP) production and melanization are two key humoral immune responses in insects. Induced synthesis of AMPs results from Toll and IMD signal transduction whereas melanization depends on prophenoloxidase (PPO) activation system. During invasion, pathogens produce toxins and other virulent factors to counteract host immune responses. Here we show that the pathways leading to PPO activation and AMP synthesis in the silkworm Bombyx mori are affected by a metalloprotease, named elastase B, secreted by Pseudomonas aeruginosa (PAO1). The metalloprotease gene (lasB) was expressed shortly after PAO1 cells had been injected into the larval silkworm hemocoel, leading to an increase of elastase activity. Injection of the purified PAO1 elastase B into silkworm hemolymph compromised PPO activation. In contrast, the protease caused a level increase of gloverin, an AMP in the hemolymph. To verify our results obtained using the purified elastase B, we infected B. mori with PAO1 ΔlasB mutant and found that PO activity in hemolymph of the PAO1 ΔlasB-infected larvae was significantly higher than that in the wild type-infected. The mutant-inhabited hemolymph had lower levels of gloverin and antimicrobial activity. PAO1 ΔlasB showed a decreased viability in the silkworm hemolymph whereas the host had a lower mortality. In addition, the effects caused by the ΔlasB mutant were restored by a complementary strain. These data collectively indicated that the elastase B produced by PAO1 is an important virulent factor that manipulates the silkworm immune system during infection.
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影响因子：
2.8
作者：
Antunez, Karina;Arredondo, Daniela;Zunino, Pablo
通讯作者：
Zunino, Pablo
影响因子：
3.1
作者：
Altincicek, Boran;Linder, Monica;Vilcinskas, Andreas
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影响因子：
4.4
作者：
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通讯作者：
Shimizu, Susumu
影响因子：
3.7
作者：
Beaufort N;Corvazier E;Mlanaoindrou S;de Bentzmann S;Pidard D
通讯作者：
Pidard D
影响因子：
6.4
作者：
Altindis E;Dong T;Catalano C;Mekalanos J
通讯作者：
Mekalanos J