This study was aimed to understand the expression of miR-146a in zebrafish (Danio rerio) and its role in regulating immune responses during Aeromonas hydrophila and Edwardsiella piscicida infections. The miR-146a expression was observed from the 1-h post fertilization (hpf) stage and gradually increased up to the early larval stage of zebrafish. The ubiquitous expression of miR-146a was detected in all tested tissues, with the highest level in gills. The expression of miR-146a was significantly increased in larvae when exposed to E. piscicida infection at 24 and 48 h post exposure (hpe). Intraperitoneally (i.p.) injected A. hydrophila and E. piscicida into adult zebrafish showed significant upregulation of miR-146a in gills. Furthermore, immune-related genes, toll-like receptor, tlr-4, transducing signaling pathway molecules, traf-6 and myd88 (bacteria-infected larvae and adults), transcription factor relA and mcp-1b (bacteria-infected adults), pro-inflammatory, il-6 (A. hydrophila-exposed larvae) and mmp-9 (bacteria-exposed larvae) were significantly repressed. In contrast, il-1β, tnf-α, cxcl-18b, and ccl-34a.4 were induced in both bacteria-challenged larvae and adults. Based on the results, it is suggested that endogenous miR-146a could act as an infection inducible miRNA in zebrafish upon A. hydrophila and E. piscicida infections; also, it could potentially regulate the immune responses in zebrafish.

中文翻译：

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miR-146a对斑马鱼嗜水气单胞菌和鱼类爱德华氏菌感染的潜在免疫调节作用

本研究旨在了解 miR-146a 在斑马鱼 (Danio rerio) 中的表达及其在调节嗜水气单胞菌和鱼类爱德华氏菌感染期间免疫反应中的作用。miR-146a 表达从受精后 1 小时 (hpf) 阶段观察到，并逐渐增加到斑马鱼的早期幼虫阶段。在所有受试组织中均检测到 miR-146a 的普遍表达，在鳃中表达水平最高。当在暴露后 24 和 48 小时（hpe）暴露于鱼腥藻感染时，miR-146a 在幼虫中的表达显着增加。腹膜内 (ip) 注射 A. hydrophila 和 E. piscicida 到成年斑马鱼中显示出鳃中 miR-146a 的显着上调。此外，免疫相关基因、toll 样受体、tlr-4、转导信号通路分子、traf-6 和 myd88（细菌感染的幼虫和成虫）、转录因子 relA 和 mcp-1b（细菌感染的成虫）、促炎因子、il-6（暴露于嗜水杆菌的幼虫）和 mmp-9（细菌-暴露的幼虫）被显着抑制。相比之下，il-1β、tnf-α、cxcl-18b 和 ccl-34a.4 在细菌攻击的幼虫和成虫中均被诱导。结果表明，内源性 miR-146a 可以作为斑马鱼感染 A.hydrophila 和 E. piscicida 的感染诱导 miRNA；此外，它还可以潜在地调节斑马鱼的免疫反应。4 在细菌攻击的幼虫和成虫中均被诱导。结果表明，内源性 miR-146a 可以作为斑马鱼感染 A.hydrophila 和 E. piscicida 的感染诱导 miRNA；此外，它还可以潜在地调节斑马鱼的免疫反应。4 在细菌攻击的幼虫和成虫中均被诱导。结果表明，内源性 miR-146a 可以作为斑马鱼感染 A.hydrophila 和 E. piscicida 的感染诱导 miRNA；此外，它还可以潜在地调节斑马鱼的免疫反应。