Schmitt Paulina, Wacyk Jurij, Morales-Lange Byron, Rojas Verónica, Guzmán Fanny, Dixon Brian, Mercado Luis
Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
Laboratorio de Biotecnología en Acuicultura (LBA), Facultad de Ciencias Agronómicas, Departamento de Producción Animal, Universidad de Chile, Santiago, Chile.
Dev Comp Immunol. 2015 Jul;51(1):160-9. doi: 10.1016/j.dci.2015.03.007. Epub 2015 Mar 26.
The aim of the present study was to characterize intestinal immune mechanisms involved in the response to β-glucans in rainbow trout. Among the immune effectors regulated in response to immunostimulants, host defense peptides (HDPs) are abundantly expressed in epithelial linings, suggesting their important role in the mucosal immune response. Therefore, the immunomodulatory properties of expressed HDPs in the epithelial intestinal cells of rainbow trout in response to the β-glucan, zymosan, were assessed. The results showed that zymosan increased the production of the HDP, cathelicidin, and the cytokine, IL-1β, in the intestinal epithelial RTgutGC cell line at the transcript and protein levels. Thus, cathelicidin-2 variants were produced and were shown to (i) induce the production of IL-1β in RTgutGC cells and (ii) display a synergic effect with zymosan in IL-1β upregulation. Importantly, the colocalization of both rtCATH-2 and IL-1β was detected in the intestinal epithelial cells of rainbow trout fed with a 0.3% zymosan-supplemented diet. We propose that trout cathelicidins are expressed by intestinal epithelial cells and exert immunomodulatory effects to improve the local intestinal immune response triggered by immunostimulants.
本研究的目的是表征虹鳟鱼对β-葡聚糖反应中涉及的肠道免疫机制。在对免疫刺激物作出反应而被调节的免疫效应因子中，宿主防御肽（HDPs）在上皮内衬中大量表达，表明它们在粘膜免疫反应中发挥重要作用。因此，评估了虹鳟鱼肠道上皮细胞中表达的HDPs对β-葡聚糖酵母聚糖的免疫调节特性。结果表明，酵母聚糖在转录和蛋白质水平上增加了肠道上皮RTgutGC细胞系中HDP、cathelicidin和细胞因子IL-1β的产生。因此，产生了cathelicidin-2变体，并显示出（i）在RTgutGC细胞中诱导IL-1β的产生，以及（ii）在IL-1β上调中与酵母聚糖显示出协同作用。重要的是，在喂食补充0.3%酵母聚糖饮食的虹鳟鱼的肠道上皮细胞中检测到rtCATH-2和IL-1β的共定位。我们提出，鳟鱼cathelicidins由肠道上皮细胞表达，并发挥免疫调节作用，以改善由免疫刺激物触发的局部肠道免疫反应。
