Álvarez Claudio Andrés, Santana Paula A, Salinas-Parra Nicolás, Beltrán Dina, Guzmán Fanny, Vega Belinda, Acosta Félix, Mercado Luis
Laboratorio de Fisiología y Genética Marina, Centro de Estudios Avanzados en Zonas Áridas, Coquimbo 1781421, Chile.
Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo 1781421, Chile.
Animals (Basel). 2022 Jun 20;12(12):1586. doi: 10.3390/ani12121586.
Antimicrobial peptides (AMP) play an essential role in the innate immune system, modulating the defense response. In a previous study, we demonstrated the antimicrobial activity of synthetic hepcidin (hep20) from rainbow trout (), and its protective effect in European sea bass () challenged with . Additionally, we described the uptake and distribution of hep20 in different tissues and leukocyte cells. Interestingly, various AMPs characterized in high vertebrates, called host defense peptides (HDPs), also possess immunomodulation activity. For that reason, the present study explores the immunomodulatory abilities of hep20 through in vitro and in vivo studies. First, a monocyte/macrophage RTS-11 cell line from rainbow trout was used to evaluate hep20 effects on pro- and anti-inflammatory cytokines in fish leukocyte cells. Next, the European sea bass juveniles were used to determine if hep20 can regulate the expression of cytokines in fish immune tissues. The results show that hep20 was uptake inner to RTS-11 cells and was able to induce the expression of IL-10, IL-1β, and TNFα at transcriptional and protein levels. Then, the European sea bass juveniles were given intraperitoneal injections of the peptide. At 1, 3, 7, 14, and 21 days post-injection (dpi), IL-10, IL -1β, and TNFα mRNA were quantified in the anterior gut, spleen, and head kidney. The hep20 was able to up-regulate cytokine gene expression in these tissues, mainly in the head kidney. Furthermore, the evaluated cytokines showed a cyclical tendency of higher to lesser expression. Finally, a bioinformatics analysis showed that the structure adopted by hep20 is similar to the γ-core domain described for cysteine-stabilized AMP, defined as immunomodulatory and antimicrobial, which could explain the ability of hep20 to regulate the cytokine expression. This study provides new insights into immunomodulatory function complementary to the previously established antimicrobial activity of hep20, suggesting a role as an HDP in teleost fish. These facts are likely to be associated with molecular functions underpinning the protective effect of fish hepcidin against pathogens.
抗菌肽（AMP）在先天性免疫系统中发挥着重要作用，调节防御反应。在先前的一项研究中，我们证明了虹鳟鱼合成的铁调素（hep20）的抗菌活性，以及其对受[具体病原体未给出]攻击的欧洲海鲈的保护作用。此外，我们描述了hep20在不同组织和白细胞中的摄取和分布。有趣的是，在高等脊椎动物中具有特征的各种抗菌肽，称为宿主防御肽（HDP），也具有免疫调节活性。因此，本研究通过体外和体内研究探索了hep20的免疫调节能力。首先，使用来自虹鳟鱼的单核细胞/巨噬细胞RTS - 11细胞系来评估hep20对鱼类白细胞中促炎和抗炎细胞因子的影响。接下来，使用欧洲海鲈幼鱼来确定hep20是否能够调节鱼类免疫组织中细胞因子的表达。结果表明，hep20被RTS - 11细胞摄取，并能够在转录和蛋白质水平上诱导IL - 10、IL - 1β和TNFα的表达。然后,给欧洲海鲈幼鱼腹腔注射该肽。在注射后1、3、7、14和21天（dpi），在前肠、脾脏和头肾中对IL - 10、IL - 1β和TNFα mRNA进行定量。hep20能够上调这些组织中细胞因子基因的表达，主要是在头肾中。此外，所评估的细胞因子显示出从高到低表达的周期性趋势。最后，生物信息学分析表明，hep20所采用的结构类似于针对半胱氨酸稳定的AMP所描述的γ - 核心结构域，该结构域被定义为具有免疫调节和抗菌作用，这可以解释hep20调节细胞因子表达的能力。本研究为hep20先前确立的抗菌活性之外的免疫调节功能提供了新的见解，表明其在硬骨鱼中作为宿主防御肽的作用。这些事实可能与鱼类铁调素对病原体保护作用的分子功能相关。
