Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai, China
International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, Shanghai, China.
Infect Immun. 2018 May 22;86(6). doi: 10.1128/IAI.00256-18. Print 2018 Jun.
Inflammation is the host self-protection mechanism to eliminate pathogen invasion. The excessive inflammatory response can result in uncontrolled inflammation, autoimmune diseases, or pathogen dissemination. Recent studies have widely shown that microRNAs (miRNAs) contribute to the regulation of inflammation in mammals by repressing gene expression at the posttranscriptional level. However, the miRNA-mediated mechanism in the inflammatory response in fish remains hazy. In the present study, the regulatory mechanism of the miR-216a-mediated inflammatory response in teleost fish was addressed. We found that the expression of miR-216a could be significantly upregulated in the miiuy croaker after challenge with and lipopolysaccharide. Bioinformatics predictions demonstrated a potential binding site of miR-216a in the 3' untranslated region of the p65 gene, and the result was further confirmed by luciferase assay. Moreover, both the mRNA and protein levels of p65 in macrophages were downregulated by miR-216a. Deletion mutant analysis of the miR-216a promoter showed that the Ap1 and Sp1 transcription factor binding sites are indispensable for the transcription of miR-216a. Further study revealed that overexpression of miR-216a suppresses inflammatory cytokine expression and negatively regulates NF-κB signaling, which inhibit an excessive inflammatory response. The collective results indicate that miR-216a plays a role as a negative regulator involved in modulating the bacterium-induced inflammatory response.
炎症是宿主消除病原体入侵的自我保护机制。过度的炎症反应会导致炎症失控、自身免疫性疾病或病原体传播。最近的研究广泛表明，microRNAs（miRNAs）通过在转录后水平抑制基因表达，有助于调节哺乳动物的炎症反应。然而，鱼类炎症反应中 miRNA 介导的机制尚不清楚。在本研究中，研究了 miR-216a 介导的硬骨鱼类炎症反应的调节机制。研究发现，miR-216a 的表达在受到 和脂多糖刺激后，可以在米氏绒螯蟹中显著上调。生物信息学预测表明，miR-216a 在 p65 基因 3'非翻译区可能有一个潜在的结合位点，而荧光素酶报告基因实验进一步证实了这一点。此外，miR-216a 下调了巨噬细胞中 p65 的 mRNA 和蛋白水平。miR-216a 启动子缺失突变分析表明，Ap1 和 Sp1 转录因子结合位点对于 miR-216a 的转录是必不可少的。进一步的研究表明，miR-216a 的过表达抑制了炎症细胞因子的表达，并负调控 NF-κB 信号通路，从而抑制过度的炎症反应。综上所述，研究结果表明，miR-216a 作为一种负调控因子，在调节细菌诱导的炎症反应中发挥作用。
