Acute stroke alters the systemic immune response as can be observed in peripheral blood; however, the molecular mechanism by which microRNA (miRNA) regulates target gene expression in response to acute stroke is unknown. We performed a miRNA microarray on the peripheral blood of 10 patients with acute ischemic stroke and 11 control subjects. Selected miRNAs were quantified using a TaqMan assay. After searching for putative targets from the selected miRNAs using bioinformatic analysis, functional studies including binding capacity and protein expression of the targets of the selected miRNAs were performed. The results reveal a total of 30 miRNAs that were differentially expressed (16 miRNAs were upregulated and 14 miRNAs were downregulated) during the acute phase of stroke. Using prediction analysis, we found that miR-340-5p was predicted to bind to the 3'-untranslated region of the arginase-1 (ARG1) gene; a luciferase reporter assay confirmed the binding of miR-340-5p to ARG1. miR-340-5p was downregulated whereas ARG1 mRNA was upregulated in peripheral blood in patients experiencing acute stroke. Overexpression of miR-340-5p in human neutrophil and mouse macrophage cell lines induced downregulation of the ARG1 protein. Transfection with miR-340-5p increased nitric oxide production after LPS treatment in a mouse macrophage cell line. Our results suggest that several miRNAs are dynamically altered in the peripheral blood during the acute phase of ischemic stroke, including miR-340-5p. Acute stroke induces the downregulation of miR-340-5p, which subsequently upregulates ARG1 protein expression.
Innate and adaptive immune responses are critically associated with the progression of fibrosis in chronic liver diseases. In this study, we aim to identify a unique immune-related gene signature representing advanced liver fibrosis and to reveal potential therapeutic targets. Seventy-seven snap-frozen liver tissues with various chronic liver diseases at different fibrosis stages (1: n = 12, 2: n = 12, 3: n = 25, 4: n = 28) were subjected to expression analyses. Gene expression analysis was performed using the nCounter PanCancer Immune Profiling Panel (NanoString Technologies, Seattle, WA, USA). Biological meta-analysis was performed using the CBS Probe PINGSTM (CbsBioscience, Daejeon, Korea). Using non-tumor tissues from surgically resected specimens, we identified the immune-related, five-gene signature (CHIT1_FCER1G_OSM_VEGFA_ZAP70) that reliably differentiated patients with low- (F1 and F2) and high-grade fibrosis (F3 and F4; accuracy = 94.8%, specificity = 91.7%, sensitivity = 96.23%). The signature was independent of all pathological and clinical features and was independently associated with high-grade fibrosis using multivariate analysis. Among these genes, the expression of inflammation-associated FCER1G, OSM, VEGFA, and ZAP70 was lower in high-grade fibrosis than in low-grade fibrosis, whereas CHIT1 expression, which is associated with fibrogenic activity of macrophages, was higher in high-grade fibrosis. Meta-analysis revealed that STAT3, a potential druggable target, highly interacts with the five-gene signature. Overall, we identified an immune gene signature that reliably predicts advanced fibrosis in chronic liver disease. This signature revealed potential immune therapeutic targets to ameliorate liver fibrosis.
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