Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
Int Immunopharmacol. 2019 May;70:135-146. doi: 10.1016/j.intimp.2018.11.024. Epub 2019 Feb 22.
Acute lung injury (ALI) is a common clinical syndrome of excessive uncontrolled inflammatory response in lung tissues with high mortality rates and limited therapeutic approaches. MicroRNAs (miRNAs) are a class of small non-coding RNAs which attach at 3'UTR of mRNA for further regulation of diverse proteins. MiRNAs are a current focus in regulating the inflammatory processes. The extent of pro-inflammatory gene activated against Staphylococcus aureus (S. aureus) is still unclear. Myeloid differentiation primary response 88 (MyD88) is involved in gram positive bacteria-induced lung inflammation by Toll-like receptors (TLRs). Then MyD88 activates NF-κB through IRAKs which are in charge of inflammation. Target prediction analyses revealed MyD88, a result of projections from multiple bio-websites, to be a putative target of miR-128. Here we probe the expression of the MyD88 and miRNA in mode of inflammation. We found up-regulated expression of MyD88 and down-regulation of miR-128 after S. aureus infection in mouse lung tissues and RAW264.7 cells via qPCR and western blotting (WB) analysis. Moreover, MyD88-miR-128 interaction was validated by luciferase assays. Then, we proved that miR-128 expression caused a reduction in IκBα and p65 phosphorylation and resulted in significant reduction in secretion of inflammatory cytokines, being consistent with the deletion of MyD88 in macrophages. It revealed that miR-128 specifically blocked the further development of inflammation through MyD88 down-regulation. Finally, we demonstrated a novel role of miR-128 that it mediates negative regulation in S. aureus induced inflammation by targeting MyD88.
急性肺损伤 (ALI) 是一种常见的临床综合征，其特征是肺部组织过度失控的炎症反应，死亡率高，治疗方法有限。microRNAs (miRNAs) 是一类小的非编码 RNA，它们可以附着在 mRNA 的 3'UTR 上，进一步调节多种蛋白质。miRNAs 是调节炎症过程的当前研究热点。金黄色葡萄球菌 (S. aureus) 激活的促炎基因的程度尚不清楚。髓样分化初级反应 88 (MyD88) 通过 Toll 样受体 (TLRs) 参与革兰氏阳性菌诱导的肺部炎症。然后，MyD88 通过 IRAKs 激活 NF-κB，IRAKs 负责炎症。靶标预测分析表明，MyD88 是多个生物网站预测的结果，是 miR-128 的一个假定靶标。在这里，我们探讨了炎症模式中 MyD88 和 miRNA 的表达。我们通过 qPCR 和 Western blot (WB) 分析发现，金黄色葡萄球菌感染后，小鼠肺组织和 RAW264.7 细胞中 MyD88 的表达上调，miR-128 的表达下调。此外，通过荧光素酶报告基因实验验证了 MyD88-miR-128 相互作用。然后，我们证明了 miR-128 表达导致 IκBα 和 p65 磷酸化减少，导致炎症细胞因子分泌显著减少，与巨噬细胞中 MyD88 的缺失一致。这表明 miR-128 通过下调 MyD88 特异性阻断炎症的进一步发展。最后，我们证明了 miR-128 的一个新作用，它通过靶向 MyD88 介导金黄色葡萄球菌诱导的炎症的负调控。
