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The expression of interleukin-32 is activated by human cytomegalovirus infection and down regulated by hcmv-miR-UL112-1.

ABSTRACT: BACKGROUND: Interleukin-32 (IL-32) is an important factor in innate and adaptive immune responses, which activates the p38MAPK, NF-kappa B and AP-1 signaling pathways. Recent reports have highlighted that IL-32 is regulated during viral infection in humans. METHODS: Enzyme-linked immunosorbent assays (ELISA) were carried out to detect IL-32 levels in serum samples. Detailed kinetics of the transcription of IL-32 mRNA and expression of IL-32 protein during human cytomegalovirus (HCMV) infection were determined by semi-quantitative RT-PCR and western blot, respectively. The expression levels of hcmv-miR-UL112-1 were detected using TaqMan® miRNA assays during a time course of 96 hours. The effects of hcmv-miR-UL112-1 on IL-32 expression were demonstrated by luciferase assay and western blot, respectively. RESULTS: Serum levels of IL-32 in HCMV-IgM positive patients (indicating an active HCMV infection) were significantly higher than those in HCMV-IgM negative controls. HCMV infection activated cellular IL-32 transcription mainly in the immediately early (IE) phase and elevated IL-32 protein levels between 6 and 72 hours post infection (hpi) in the human embryonic lung fibroblast cell line, MRC-5. The expression of hcmv-miR-UL112-1 was detected at 24 hpi and increased gradually as the HCMV-infection process was prolonged. In addition, it was demonstrated that hcmv-miR-UL112-1 targets a sequence in the IL-32 3'-UTR. The protein level of IL-32 in HEK293 cells could be functionally down-regulated by transfected hcmv-miR-UL112-1. CONCLUSIONS: IL-32 expression was induced by active HCMV infection and could be functionally down-regulated by ectopically expressed hcmv-miR-UL112-1. Our data may indicate a new strategy of immune evasion by HCMV through post-transcriptional regulation.

SUBMITTER: Huang Y

PROVIDER: S-EPMC3598236 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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The expression of interleukin-32 is activated by human cytomegalovirus infection and down regulated by hcmv-miR-UL112-1.

Huang Yujing Y Qi Ying Y Ma Yanping Y He Rong R Ji Yaohua Y Sun Zhengrong Z Ruan Qiang Q

Virology journal 20130212

<h4>Background</h4>Interleukin-32 (IL-32) is an important factor in innate and adaptive immune responses, which activates the p38MAPK, NF-kappa B and AP-1 signaling pathways. Recent reports have highlighted that IL-32 is regulated during viral infection in humans.<h4>Methods</h4>Enzyme-linked immunosorbent assays (ELISA) were carried out to detect IL-32 levels in serum samples. Detailed kinetics of the transcription of IL-32 mRNA and expression of IL-32 protein during human cytomegalovirus (HCMV ...[more]

PMID: 23402302

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Project description:Human Cytomegalovirus (HCMV) encodes multiple microRNAs (miRNAs) whose functions are just beginning to be uncovered. Using in silico approaches, we identified the Toll-Like Receptor (TLR) innate immunity pathway as a possible target of HCMV miRNAs. Luciferase reporter assay screens further identified TLR2 as a target of HCMV miR-UL112-3p. TLR2 plays a major role in innate immune response by detecting both bacterial and viral ligands, including HCMV envelope proteins gB and gH. TLR2 activates a variety of signal transduction routes including the NFκB pathway. Furthermore, TLR2 plays an important role in controlling CMV infection both in humans and in mice. Immunoblot analysis of cells transfected with a miR-UL112-3p mimic revealed that endogenous TLR2 is down-regulated by miR-UL112-3p with similar efficiency as a TLR2-targeting siRNA (siTLR2). We next found that TLR2 protein level decreases at late times during HCMV infection and correlates with miR-UL112-3p accumulation in fibroblasts and monocytic THP1 cells. Confirming direct miR-UL112-3p targeting, down-regulation of endogenous TLR2 was not observed in cells infected with HCMV mutants deficient in miR-UL112-3p expression, but transfection of miR-UL112-3p in these cells restored TLR2 down-regulation. Using a NFκB reporter cell line, we found that miR-UL112-3p transfection significantly inhibited NFκB-dependent luciferase activity with similar efficiency as siTLR2. Consistent with this observation, miR-UL112-3p transfection significantly reduced the expression of multiple cytokines (IL-1β, IL-6 and IL-8) upon stimulation with a TLR2 agonist. Finally, miR-UL112-3p transfection significantly inhibited the TLR2-induced post-translational activation of IRAK1, a kinase located in the upstream section of the TLR2/NFκB signaling axis. To our knowledge, this is the first identified mechanism of TLR2 modulation by HCMV and is the first report of functional targeting of TLR2 by a viral miRNA. These results provide a novel mechanism through which a HCMV miRNA regulates the innate immune response by down-regulating TLR-2 expression.

Project description:BackgroundHypoxia is a hallmark of cancer and is associated with poor prognosis. However, the molecular mechanism by which hypoxia promotes tumor progression remains unclear. MicroRNAs dysregulation has been shown to play a critical role in the tumor and tumor microenvironment. Here, we investigated the roles of miR-495 and miR-5688 in human non-small cell lung cancer (NSCLC) and their underlying mechanism.MethodsThe expression levels of miR-495 and miR-5688 in human NSCLC tissue specimens were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Deferoxamine (DFO) was used to determine whether the regulation of miR-495 and miR-5688 under hypoxia was dependent on hypoxia-inducible factor 1-alpha (HIF-1α). Furthermore, the functions of miR-495 and miR-5688 in tumor progression were evaluated using colony formation, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), wound healing, transwell assays, and xenograft model. Two algorithms, PicTAR and Targetscan, were used to predict the target gene of these two miRNAs, and dual-luciferase reporter assay was conducted to confirm the target. The unpaired two-tailed t test, Pearson correlation analysis, and Fisher's exact probability test were performed for statistical analyses.ResultsTwo miRNAs, miR-495 and miR-5688, were found to participate in NSCLC progression under hypoxia. They were down-regulated in NSCLC tissues compared with normal tissues. We determined that hypoxia led to the down-regulation of miR-495 and miR-5688 in NSCLC cells, which was independent of HIF-1α and cellular metabolic energy. In addition, miR-495 and miR-5688 suppressed cell proliferation, migration, and invasion in vitro. The NSCLC xenograft model showed that miR-495 and miR-5688 inhibited tumor formation in vivo. Interestingly, we found that miR-495 and miR-5688 had the same target, interleukin-11 (IL-11). Recombinant human IL-11 counteracted the effects of miR-495 and miR-5688 on NSCLC cells, suggesting that miR-495 and miR-5688 executed their tumor suppressive role by repressing IL-11 expression.ConclusionWe found that hypoxia down-regulated the expression levels of miR-495 and miR-5688 in NSCLC to enhance IL-11 expression and tumor progression, indicating that the miR-495/miR-5688/IL-11 axis may serve as a therapeutic target and potential biomarker for NSCLC.

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The expression of interleukin-32 is activated by human cytomegalovirus infection and down regulated by hcmv-miR-UL112-1.

Publications

The expression of interleukin-32 is activated by human cytomegalovirus infection and down regulated by hcmv-miR-UL112-1.

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