Huang Xiazi, Mao Wei, Yi Yonghao, Lu Yubin, Liu Feihong, Deng Li
Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518055, China.
Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518055, China.
Dev Comp Immunol. 2024 May;154:105144. doi: 10.1016/j.dci.2024.105144. Epub 2024 Feb 3.
Antimicrobial peptides (AMPs) are an essential part of the vertebrate innate immune system. Piscidins are a family of AMPs specific in fish. In our previous investigation, we identified four paralogous genes of piscidins in the orange-spotted grouper (Epinephelus coicodes), which exhibited distinct activities against bacteria, fungi, and parasitic ciliated protozoa. Piscidins demonstrated their capability to modulate the expression of diverse immune-related genes; however, their precise immunoregulatory functions remain largely unexplored. In this study, we examined the immunomodulatory properties of putative mature peptides derived from four E. coicodes piscidins (ecPis1S, ecPis2S, ecPis3S, and ecPis4S) in head kidney leukocytes (HKLs) or monocytes/macrophages (MO/MΦ)-like cells isolated from E. coicodes. Our data demonstrate that E. coicodes piscidins exhibit immunomodulatory activities supported by multiple lines of evidence. Firstly, all four piscidins displayed chemotactic activities towards HKLs, with the most potent chemotactic activity observed in ecPis2S. Secondly, stimulation with E. coicodes piscidins enhanced respiratory burst and phagocytic activity in MO/MФ-like cells, with ecPis3S showing the highest efficacy in increasing phagocytosis of MO/MΦ-like cells. Thirdly, mRNA expression levels of chemokine receptors, Toll-like receptors, T cell receptors, and proinflammatory cytokines were modulated to varying extents by the four piscidins in E. coicodes HKLs. Overall, our findings indicate that the immunological activities of these four paralogous piscidins from E. coicodes are exhibited in a paralog-specific and concentration-dependent manner, highlighting their distinct and versatile immunomodulatory properties. This study makes a significant contribution to the field of fish AMPs immunology by elucidating the novel mechanisms through which members of the piscidin family exert their immunomodulatory effects. Moreover, it provides valuable insights for further exploration of fish immunomodulating agents.
抗菌肽（AMPs）是脊椎动物先天免疫系统的重要组成部分。鱼抗菌肽是鱼类特有的一类抗菌肽。在我们之前的研究中，我们在点带石斑鱼（Epinephelus coicodes）中鉴定出了四个鱼抗菌肽的旁系同源基因，它们对细菌、真菌和寄生纤毛虫表现出不同的活性。鱼抗菌肽显示出调节多种免疫相关基因表达的能力；然而，它们精确的免疫调节功能在很大程度上仍未被探索。在这项研究中，我们研究了从点带石斑鱼的四种鱼抗菌肽（ecPis1S、ecPis2S、ecPis3S和ecPis4S）衍生的假定成熟肽在点带石斑鱼头肾白细胞（HKLs）或单核细胞/巨噬细胞（MO/MΦ）样细胞中的免疫调节特性。我们的数据表明，点带石斑鱼的鱼抗菌肽表现出多种证据支持的免疫调节活性。首先，所有四种鱼抗菌肽对HKLs都表现出趋化活性，其中ecPis2S的趋化活性最强。其次，用点带石斑鱼的鱼抗菌肽刺激可增强MO/MФ样细胞中的呼吸爆发和吞噬活性，ecPis3S在增加MO/MΦ样细胞吞噬作用方面显示出最高的功效。第三，四种鱼抗菌肽在点带石斑鱼HKLs中不同程度地调节了趋化因子受体、Toll样受体、T细胞受体和促炎细胞因子的mRNA表达水平。总体而言，我们的研究结果表明，这四种来自点带石斑鱼的旁系同源鱼抗菌肽的免疫活性以旁系同源特异性和浓度依赖性方式表现出来，突出了它们独特而多样的免疫调节特性。这项研究通过阐明鱼抗菌肽家族成员发挥免疫调节作用的新机制，为鱼类AMPs免疫学领域做出了重大贡献。此外，它为进一步探索鱼类免疫调节剂提供了有价值的见解。
