A newly identified NLR-like gene participates in bacteria and virus infection possibly through regulating hemocytes apoptosis in shrimp
A newly identified NLR-like gene participates in bacteria and virus infection possibly through regulating hemocytes apoptosis in shrimp
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DOI：
10.1016/j.dci.2022.104395
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发表时间：
2022-03-25
影响因子：
2.9
通讯作者：
Li, Fuhua
中科院分区：
文献类型：
--
作者：
Li, Xuechun;Li, Shihao;Li, Fuhua
核苷酸结合寡聚化结构域(NOD)样受体(NLRs)在先天免疫中发挥重要作用。此前，我们在南美白对虾中发现了一个NLR样基因LvNLRPL1，并发现它参与弧菌感染和调节血细胞的凋亡。然而，目前还不清楚虾中是否存在其他类似NLR的基因，以及它们在病毒感染过程中的功能。本研究在南美白对虾中发现了一个新的NLR样基因(LvNLRPL2)，并对其功能进行了研究。LvNLRPL2在血细胞中高表达，对副溶血性弧菌和白斑综合征病毒(WSSV)感染均有反应。LvNLRPL2基因敲除后可显著促进弧菌的增殖，降低副溶血性弧菌感染对虾的死亡率，而抑制对虾体内WSSV的繁殖，表明LvNLRPL2在弧菌和WSSV感染过程中具有明显的作用。LvNLRPL2基因敲除后，血细胞凋亡率增加，LvCaspase2、3、5表达水平显著上调。此外，LvNLRPL2还可以通过其Nacht结构域与LvNLRPL1形成杂二聚体。提示LvNLRPL2可能通过与LvNLRPL1形成异源二聚体，抑制血细胞的凋亡，从而在抗细菌感染的同时促进WSSV的增殖。这些数据将有助于了解NLR样基因在甲壳类动物中的功能及其调控机制。
The nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) play important roles in innate immunity. Previously, we identified an NLR-like gene, LvNLRPL1, and found that it participated in Vibrio infection and regulated hemocytes apoptosis in the Pacific whiteleg shrimp Litopenaeus vannamei. However, it is still unclear whether other NLR-like genes exist in shrimp and how they function during virus infection. In the present study, a novel NLR-like gene (LvNLRPL2) was identified and functionally characterized in L. vannamei. LvNLRPL2 was highly expressed in hemocytes and responsive to both Vibrio parahaemolyticus and white spot syndrome virus (WSSV) infection. Knockdown of LvNLRPL2 could markedly increase the proliferation of Vibrio and the mortality of shrimp infected with V. parahaemolyticus, whereas inhibit in vivo WSSV propagation in shrimp, indicating its distinct roles during Vibrio and WSSV infection. After LvNLRPL2 knockdown, the apoptotic rate of hemocytes increased, and the expression levels of LvCaspase 2, 3 and 5 were significantly up-regulated. In addition, LvNLRPL2 could form a hetero-dimer with LvNLRPL1 through their NACHT domains. These results suggest that LvNLRPL2 might resist bacterial infection while promote WSSV propagation by forming heterodimer with LvNLRPL1 and then inhibiting apoptosis of hemocytes. These data will be helpful for understanding the functions of NLR-like genes and their regulation mechanisms in crustaceans.