Ruction Analysis Of MicroRNA-146a And MicroRNA-155 In Inhalation Injury

According to statistics, inhalation injury patients can increase more than 20% in overall mortality. Although with the development of science, the overall treatment of burns have made great progress. For the inhalation injury, the current clinical treatment is still at the level of passive symptomatic treatment, such as opening the airway(tracheostomy), oxygen, mechanical ventilation, lacking of initiative of specific treatment, indicating that we have so far for inhalation injury is also relatively superficial understanding, the reason is that its pathogenesis and pathological changes mechanism has not been elucidated yet. Therefore, the study of inhalation injury exact pathogenesis and effective interventions it is necessary.Clinical studies and animal experiments show that: inflammatory cell infiltration, a large number of free radical generation, over-expression of pro-inflammatory mediators in the lung tissue and activation of inflammatory signaling pathway are important in the pathogenesis of early inhalation lung injury. Nuclear factor κB(NF-κB) signaling pathway is one of the most critical one, which mediated by a variety of inhalation injury pathophysiology. Thus, it has a positive meaning that inhibiting the activation of NF-κB signaling pathway for blocking inhalation lung injury pathogenic mechanisms to alleviate their symptoms, reversing its pathophysiological process.MicroRNAs(miRNAs) are a recently discovered class of small noncoding RNAs that are implicated in many physiological and pathological processes as post-transcriptional repressors of gene expression. Mature miRNAs can specifically bind to 3′-UTRs of target cellular mRNA in turn triggering mRNA degradation or inhibition of translation. In general, miRNAs act as key regulators in development, differentiation, homeostasis, and cancers.As the earlier reaction of the cells receiving exogeous and endogenous pressure, miRNAs are involved in modulating immune response. However, the regulatory role of miRNAs in Inhalation lung injury is not clear. Previous studies indicated that H. pylori infection in gastric epithelial cell model shows the promoter sequence miR-146 a and miR-155 gene contains binding sites for NF-κB. It confirmed that inducing the high expression of miR-146 a and mi R-155 by inflammatory infection is subject to regulate NF-κB signaling pathway. Therefore, we based on preliminary experiments, look for miR-146 a and miR-155 new target genes and verify its mechanism of action in inhalation injury. MethodsStudies on the fuction of mi R-146 a and miR-155 in inhalation injury. The potential targets of miRNAs in gastric epithelium cells were identified by bioinformatics prediction, luciferase reporter assay, Realtime PCR and Western blot. Examination of miRNAs function in inhalation injury were performed by overexpression and inhibition of mi RNAs, RNAi, immunofluorescence. Results1. Prediction and identification of miR-146 a andmiR-155 targets.FAF-2, Notch-2 are potential targets of miR-146 a, and MyD88 is potential target of mi R-155. MiR-146 a and miR-155 might down-regulate the targets protein through mRNA degradation or translation inhibition.2. Inhibition of proinflammatory cytokines of miR-146 a and mi R-155 in inhalation injury.miR-146 a and miR-155 mimics significantly attenuated the mRNA and protein levels of cyclooxygenase-2(COX-2), Interleukin-8(IL-8), Growth-related oncogene-α(GRO-α), Monocyte Chemotactic Peptide-1(MCP-1), Tumor Necrosis Factor(TNF-α), Interleukin-1β(P<0.05), and the effect of miR-146 a and miR-155 in modulating the inflammation may be as a secondary effect through diminishing NF-κB activity. MiR-155 may be involved in the negative feedback regulation of inflammation. Conclusions1. As the targets of miR-146 a and miR-155, FAF-2, Notch-2, MyD88, were identified. miR-146 a and miR-155 could significantly attenuate the mRNA and protein levels of proinflammatory cytokines induced by CSE infection, and the effects of miR-146 a and miR-155 in modulating the inflammation may be as a secondary effect through diminishing NF-κB activity.2. MiR-146 a and miR-155 may function as novel negative regulators. Together with its targets, miR-155 and mi R-146 a may be involved in the negative feedback regulation in inflammation response of in inhalation injury.Furthermore, the altered miR-146 a and miR-155 expression may establish a potential link between miRNAs and pathogenesis.