Schmidt Wolfgang M, Spiel Alexander O, Jilma Bernd, Wolzt Michael, Müller Markus
Department of Clinical Pharmacology, Division of Pharmacogenetics & Imaging, Medical University of Vienna, A-1090 Vienna, Austria.
Biochem Biophys Res Commun. 2009 Mar 13;380(3):437-41. doi: 10.1016/j.bbrc.2008.12.190. Epub 2009 Jan 29.
To gain insight into microRNAs (miRNAs) involved in the regulation of the human innate immune response, we screened for differentially expressed miRNAs in circulating leukocytes in an in vivo model of acute inflammation triggered by Escherichia coli lipopolysaccharide (LPS) infusion. Leukocyte RNA was isolated from venous blood samples obtained from healthy male volunteers before and 4h after LPS-infusion. After fluorescence labeling, RNA samples were hybridized to microarrays containing capture probes for measuring the abundance of more than 600 human miRNAs. Target genes were predicted for differentially expressed miRNAs and then compared to changes in genome-wide expression levels, which had been established in a previous study. Data analysis revealed that five miRNAs consistently responded to LPS-infusion, four of which were down-regulated (miR-146b, miR-150, miR-342, and let-7g) and one was up-regulated (miR-143). The miR-150 and mir-342 response was confirmed by real-time PCR. By correlating to measured LPS-induced changes of the leukocyte transcriptome, we next searched for predicted target genes, whose stability might be under (co-) control by these miRNAs. We found that the rapid transcriptional activation during acute inflammation of select genes, such as the gene encoding interleukin-1 receptor-associated kinase 2 (IRAK2) might be facilitated by decreased levels of LPS-responsive miRNAs. The increased level of miR-143 might be associated with the pronounced down-regulation of the B-cell CLL/lymphoma 2 (BCL2) gene expression during LPS endotoxemia, and could further be involved in the translational silencing of several other predicted inflammation-related target genes. This is the first in vivo study to demonstrate relative abundance of miRNA levels in peripheral blood leukocytes during acute LPS-induced inflammation. The miRNAs and their potential target genes identified herein contribute to the understanding of the complex transcriptional program of innate immunity initiated by pathogens.
为深入了解参与人类固有免疫反应调节的微小RNA（miRNA），我们在由大肠杆菌脂多糖（LPS）输注引发的急性炎症体内模型中，筛选循环白细胞中差异表达的miRNA。从健康男性志愿者在LPS输注前和输注后4小时采集的静脉血样本中分离白细胞RNA。荧光标记后，将RNA样本与包含捕获探针的微阵列杂交，以测量600多种人类miRNA的丰度。对差异表达的miRNA预测其靶基因，然后与先前研究中确定的全基因组表达水平变化进行比较。数据分析显示，五种miRNA对LPS输注持续有反应，其中四种下调（miR-146b、miR-150、miR-342和let-7g），一种上调（miR-143）。miR-150和miR-342的反应通过实时PCR得到证实。通过与测量的LPS诱导的白细胞转录组变化相关联，我们接下来寻找预测的靶基因，其稳定性可能受这些miRNA的（共）调控。我们发现，在急性炎症期间，某些基因（如编码白细胞介素-1受体相关激酶2（IRAK2）的基因）的快速转录激活可能因LPS反应性miRNA水平降低而促进。miR-143水平升高可能与LPS内毒素血症期间B细胞淋巴瘤/白血病-2（BCL2）基因表达的明显下调有关，并且可能进一步参与其他几种预测的炎症相关靶基因的翻译沉默。这是第一项证明急性LPS诱导炎症期间外周血白细胞中miRNA水平相对丰度的体内研究。本文鉴定的miRNA及其潜在靶基因为理解病原体引发的固有免疫复杂转录程序做出了贡献。
