MicroRNAs are 19 to 23 nt RNAs that post-transcriptionally regulate gene expression. Human cells express several hundred miRNAs which regulate important biological pathways such as development, proliferation, and apoptosis. Recently, 12 microRNA genes have been identified within the genome of Kaposis sarcoma-associated herpesvirus; however, their functions are still unknown. To identify host cellular genes that may be targeted by these novel viral regulators, we performed gene expression profiling in cells stably expressing KSHV-encoded miRNAs. Data analysis revealed a set of 81 genes whose expression was significantly changed in the presence of miRNAs. While the majority of changes were below 2-fold, eight genes were down-regulated between 4- and 20-fold. We confirmed miRNA-dependent regulation for three of these genes and found that protein levels of thrombospondin 1 (THBS1) were decreased >10-fold. THBS1 has previously been reported to be down-regulated in KS lesions and has known activity as a strong tumor suppressor and anti-angiogenic factor, exerting its anti-angiogenic effect in part by activating the latent form of TGF-b. We show that reduced THBS1 expression in the presence of viral miRNAs translates into decreased TGF-b activity. These data suggest that KSHV-encoded miRNAs may contribute directly to pathogenesis by down-regulation of THBS1, a major regulator of cell adhesion, migration, and angiogenesis.
Identification of cellular genes targeted by KSHV-encoded microRNAs.
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View SamplesMicroRNAs are small, non-coding RNAs that post-transcriptionally regulate gene expression by binding to 3UTRs of target mRNAs. Kaposis sarcoma-associated herpesvirus (KSHV), a virus linked to malignancies including primary effusion lymphoma (PEL), encodes 12 miRNA genes, but only a few regulatory targets are known. We found that KSHV-miR-K12-11 shares 100% seed-sequence homology with hsa-miR-155, a miRNA frequently found up-regulated in lymphomas and critically important for B cell development. Based on this seed-sequence homology, we hypothesized that both miRNAs regulate a common set of target genes and as a result, could have similar biological activities.
Kaposi's sarcoma-associated herpesvirus encodes an ortholog of miR-155.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Viral microRNA targetome of KSHV-infected primary effusion lymphoma cell lines.
Cell line
View SamplesPrimary effusion lymphoma (PEL) is caused by Kaposi''s sarcoma-associated herpesvirus (KSHV) and frequently also harbors Epstein-Barr virus (EBV). The expression of KSHV- and, often, EBV-encoded microRNAs (miRNAs) in PELs suggests a role for these miRNAs in viral latency and lymphomagenesis. Here we report the direct and transcriptome-wide identification of miRNA target sites for all miRNAs expressed in PEL cell lines. The resulting dataset revealed that KSHV miRNAs directly target more than 2000 cellular mRNAs encoding proteins that function in pathways with relevance to KSHV pathogenesis. Moreover, ~50% of these mRNAs are also targeted by EBV miRNAs, via distinct binding sites. In addition to a known viral analog of miR-155, we show that KSHV encodes a viral miRNA that mimics cellular miR-142-3p function. In summary, these experiments identify an extensive list of mRNAs targeted by KSHV miRNAs and indicate that these are likely to strongly influence viral replication and pathogenesis. Overall design: small RNA sequencing, 3 samples Ago2 (EIF2C2) PAR-CLIP, 2 samples
Viral microRNA targetome of KSHV-infected primary effusion lymphoma cell lines.
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View SamplesPolycomb repressive complex 2 (PRC2) maintains developmental regulator genes in a repressed state through methylation of histone H3 at lysine 27 (H3K27me3) and is necessary for cell differentiation. We and others have previously found that the PRC2 subunit Suz12 interacts with RNA in vitro and other studies have shown that Ezh2 and Jarid2 also possess RNA binding function. The interaction of PRC2 with RNA has been suggested to regulate PRC2 targeting or enzymatic activity, but the RNAs directly bound by PRC2 in cells, and the role of each PRC2 RNA binding subunit, remain unclear. We have used different CLIP techniques, which use UV-crosslinking to allow detection of direct Suz12-RNA interactions as they occur in living mouse ES cells. Suz12 binds nascent RNA and has a preference for interaction with the 3'UTR, showing it does have binding specificity in cells. RNAs bound by Suz12 at the 3'UTR encode developmental regulator genes. Suz12 remains bound to RNA upon deletion of Ezh2 or Jarid2 showing that it binds RNA independently of other PRC2 subunits. We also show that binding of Suz12 to RNA or chromatin is mutually inhibitory. Although Ezh2 and Jarid2 also bind RNA, Ezh2 and Jarid2 deletion causes an increase in Suz12 RNA binding, without changing its specificity, which reflects the loss of Suz12 from chromatin. Similarly, disruption of Suz12-RNA interactions by RNA polymerase II inhibition or RNase treatment increases Suz12 binding to chromatin. These results therefore suggest that Suz12 acts as an RNA sensor, binding to the 3'UTR of nascent RNAs and modulating the interaction of PRC2 with chromatin. Overall design: Total RNAseq libraires from of Mus musculus Ezh2 fl/fl Stem Cells after and before Tamoxifen treatment.Up to three replicates per condition
The interaction of PRC2 with RNA or chromatin is mutually antagonistic.
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View SamplesGenomic instability predisposes cells to malignant transformation, however the molecular mechanisms that allow for the propagation of cells with a high-degree of genomic instability remains unclear. Here we report that miR-181a is able to transform fallopian tube secretory epithelial cells- the precursor cell type for the majority of high-grade serous ovarian cancers- through the inhibition of RB1 and simultaneously drives a cell protective inhibition of the stimulator-of-interferon-genes (STING) in order to maintain a microenvironment conducive to the propagation of cells with a high-degree of genomic instability. We found that miR-181a inhibition of RB1 leads to profound nuclear defects, genomic instability, and nuclear rupture resulting in a persistence of genomic material in the cytoplasm. While normally, this persistence of genomic material in the cytoplasm induces interferon response through STING to drive cell death, miR-181a directly downregulates STING and prevents apoptosis. The most common mechanism by which oncogenic miRNAs promote tumorigenesis is through the direct inhibition of tumor suppressor genes, however our studies highlight a new mechanism of oncomiR transformation through the combination of tumor suppressor gene inhibition and abrogation of immune surveillance that initiates and propagates tumor cell survival. Importantly, we found that miR-181a induction in ovarian patient tumors is tightly associated with decreased IFNg response and downregulation of lymphocyte infiltration amd leukocyte fraction. To date, DNA oncoviruses are the only known inhibitors of STING that allow for cellular transformation thus, our findings are the first to identify a genetic factor, miR-181a, that can downregulate STING expression, suppress activation of the immunosurveillance machinery, and impair signaling in cancer cells creating a survival advantage. Our studies support the notion that the induction of STING-mediated signaling in cancer cells could lead directly to cancer cell death however these effects are abrogated by miR-181a. Given the recent interest in the development of STING agonists as a strategy to harness the immune system to treat cancer, this study introduces novel patient selective biomarker as well as potent therapeutic target for development of the most effective combination treatments.
miR-181a initiates and perpetuates oncogenic transformation through the regulation of innate immune signaling.
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View SamplesStudy the role of klotho as a tumor suppressor in colorectal cancer.
Klotho suppresses colorectal cancer through modulation of the unfolded protein response.
Cell line
View SamplesExtracorporeal shockwave treatment was shown to improve orthopaedic diseases, wound healing and to stimulate lymphangiogenesis in vivo. The aim of this study was to investigate in vitro shockwave treatment (IVSWT) effects on lymphatic endothelial cell (LEC) behavior and lymphangiogenesis. We analyzed migration, proliferation, vascular tube forming capability and marker expression changes of LECs after IVSWT compared with HUVECs. Finally, transcriptome- and miRNA analyses were conducted to gain deeper insight into the IVSWT-induced molecular mechanisms in LECs. The results indicate that IVSWT-mediated proliferation changes of LECs are highly energy flux density-dependent and LEC 2D as well as 3D migration was enhanced through IVSWT. IVSWT suppressed HUVEC 3D migration but enhanced vasculogenesis. Furthermore, we identified podoplaninhigh and podoplaninlow cell subpopulations, whose ratios changed upon IVSWT treatment. Transcriptome- and miRNA analyses on these populations showed differences in genes specific for signaling and vascular tissue. Our findings help to understand the cellular and molecular mechanisms underlying shockwave-induced lymphangiogenesis in vivo.
Molecular and cellular effects of in vitro shockwave treatment on lymphatic endothelial cells.
Specimen part
View SamplesWe aimed to determine the infect of Ascaris suum infection on mucosal immune pathways in pigs
Ascaris Suum Infection Downregulates Inflammatory Pathways in the Pig Intestine In Vivo and in Human Dendritic Cells In Vitro.
Specimen part
View SamplesCD25+ regulatory T cells develop in the thymus (nTregs), but may also be generated in the periphery upon stimulation of naive CD4 T cells under appropriate conditions (iTregs). The mechanisms that regulate the generation of peripheral iTregs are largely unknown.
Analysis of the transcriptional program of developing induced regulatory T cells.
Specimen part, Treatment, Subject, Time
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