Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China.
Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, China.
Dev Comp Immunol. 2022 Feb;127:104293. doi: 10.1016/j.dci.2021.104293. Epub 2021 Oct 12.
Arginine metabolism pathway enzymes and products are important modulators of several physiological processes in animals, including immune response. Although some components of the arginine metabolic pathway have been reported in penaeid shrimps, no systematic study has explored all the key pathway enzymes involved in shrimp antimicrobial response. Here, we explored the role of the three key arginine metabolism enzymes (nitric-oxide synthase (NOS), arginase (ARG), agmatinase (AGM)) in Penaeus vannamei antimicrobial immunity. First, P. vannamei homologs of ARG and AGM (PvARG and PvAGM) were cloned and found to be evolutionally conserved with invertebrate counterparts. Transcript levels of PvARG, PvAGM, and PvNOS were ubiquitously expressed in healthy shrimp tissues and induced in hemocytes and hepatopancreas upon challenge with Gram-negative (Vibrio parahaemolyticus) and Gram-positive (Streptoccocus iniae) bacteria, suggesting their involvement in shrimp antimicrobial immune response. Besides, RNA interference knockdown and enzyme activity assay revealed an antagonistic relationship between PvARG/PvAGM and PvNOS, while this relationship was broken upon pathogen stimulation. Interestingly, knockdown of PvNOS increased Vibrio abundance in shrimp hemolymph, whereas knockdown of PvAGR reduced Vibrio abundance. Taken together, our present data shows that homologs of the key arginine metabolism pathway enzymes in penaeid shrimp (PvARG, PvAGM, and PvNOS) work synergistically and/or antagonistically to modulate antibacterial immune response.
精氨酸代谢途径的酶和产物是动物中几种生理过程（包括免疫反应）的重要调节剂。尽管已在对虾中报道了精氨酸代谢途径的一些成分，但尚无系统研究探讨参与虾类抗菌反应的所有关键途径酶。在这里，我们探讨了三个关键的精氨酸代谢酶（一氧化氮合酶（NOS），精氨酸酶（ARG），胍氨酸酶（AGM））在凡纳滨对虾抗菌免疫中的作用。首先，克隆了凡纳滨对虾的 ARG 和 AGM 同源物（PvARG 和 PvAGM），并发现它们与无脊椎动物的对应物在进化上是保守的。PvARG、PvAGM 和 PvNOS 的转录水平在健康虾组织中普遍表达，并在受到革兰氏阴性（副溶血弧菌）和革兰氏阳性（无乳链球菌）细菌挑战时在血细胞和肝胰腺中诱导表达，表明它们参与了虾类的抗菌免疫反应。此外，RNA 干扰敲低和酶活性测定显示 PvARG/PvAGM 和 PvNOS 之间存在拮抗关系，而这种关系在病原体刺激时被打破。有趣的是，PvNOS 的敲低会增加虾血液中的弧菌丰度，而 PvAGR 的敲低会减少弧菌的丰度。综上所述，我们目前的数据表明，对虾精氨酸代谢途径关键酶的同源物（PvARG、PvAGM 和 PvNOS）协同作用和/或拮抗作用来调节抗菌免疫反应。
