急性肺损伤下调性microRNAs的抑炎作用与机制研究

The effect of microRNAs (miRNAs) in acute lung injury (ALI) is not clear and yet to be further clarified. Our previous study found that a lot of miRNAs in the lung tissue of ALI mice induced by LPS significantly up/down regulated, and we has also deeply studied miR-155 which were high expressed dury ALI. Down-regulated miRNAs may play more important role in target gene through negative regulation and worth to be further research. On this Project, we will define the expression of miRNAs of ARDS patients related to infection through miRNAs microarray and real-time quantitative PCR firstly; secondly, 3 to 5 miRNAs which were down-regulated both in patients and ALI mice induced by LPS, which had been studied in our former project, will be selected and over-expressed with miRNA mimics to detect the effection in proliferation and inflammatory reaction.then, one or more target genes is selected by prediction software and the effect of miRNA to target gene will be studied through target gene knock-out technology. one or more miRNAs will be selected and transfected by lentiviral vector technology to build over-expression miRNAs particle and then spray into mice body with ALI induced by LPS to find the therapy effection and clarify the inflammatory response and mechanisms.All our studies will provide experimental value and methods for farther studies in the field of mechanisms and treatments of ALI.

microRNAs（miRNAs）在急性肺损伤（ALI）中的作用尚有待于进一步阐明。我们的前期研究发现在ALI小鼠多个miRNAs上调/下调，并对上调miR-155进行了系统的研究。但下调miRNAs在ALI的炎症反应和内皮损伤中可能起更加重要的作用。为此，本课题拟首先采用基因芯片和RT-PCR检测感染相关ALI/ARDS患者外周血miRNAs的表达；然后选择在ALI模型小鼠和患者中均下调的miRNAs 3-5个，通过miRNA mimics 转染技术，分别检测其对巨噬细胞及血管内皮细胞增殖及炎症表达的影响，并根据预测软件分析选择可能的靶基因，通过敲除目标靶基因探讨miRNAs对靶基因的调控作用；随后，通过慢病毒载体转染技术，构建miRNAs过表达颗粒；最后明确miRNAs过表达颗粒对ALI炎症信号途径及肺损伤程度的影响。为阐明miRNAs拮抗炎症反应、机制和应用价值提供实验依据。

急性呼吸窘迫综合征（ARDS）/急性肺损伤（ALI）是临床严重的并发症。尽管随着呼吸支持技术的改进和综合治疗的进展，ARDS/ALI的病死率有所下降，但仍然是危重病人的主要致死因素之一。在前期的研究中我们发现ALI发病过程中可出现多个microRANs（miRNAs）出现上调或下调。在下调miRNAs中，发现miR-125b在ALI发病过程中可能的潜在作用。因此，我们评估基于mir-125b策略治疗脂多糖（LPS）诱导的小鼠ALI的可行性。我们发现，在LPS诱导的ALI小鼠中支气管肺泡灌洗（BAL）液miR-125b表达水平明显降低。值得注意的是，我们报道了miR-125b表达调控能保持ALI小鼠体重和生存。此外，强制表达mir-125b显著降低LPS诱导的肺部炎症，如减少支气管肺泡灌洗（BAL）液中细胞总数和中性粒细胞计数、炎性细胞因子以及趋化因子等。此外，强制表达miR-125b降低LPS诱导的肺通透性，减少BAL液中总蛋白、白蛋白和IgM水平。同时，强制表达mir-125显著改善LPS诱导ALI小鼠肺组织病理学变化。在临床上，我们发现血清miR-125b表达下降与急性呼吸窘迫综合征患者疾病的严重程度呈负相关。我们的研究结果强烈表明，强制表达miR-125b可有效改善LPS诱导的ALI，表明基于mir-125b的治疗在ARDS中有一定的应用前景。