Pluripotent stem cells (PSCs) deficient for microRNAs (miRNAs), such as Dgcr8-/- or Dicer-/- embryonic stem cells (ESCs), contain no mature miRNA and cannot differentiate into somatic cells. How miRNA deficiency causes differentiation defects remains poorly understood. Here, we report that miR-302 is sufficient to enable neural differentiation of differentiation-incompetent Dgcr8-/- ESCs. Our data showed that miR-302 directly suppresses the tumor suppressor p53, which is modestly upregulated in Dgcr8-/- ESCs and serves as a barrier restricting neural differentiation. We demonstrated that direct inactivation of p53 by SV40 large T antigen, a short hairpin RNA against Trp53, or genetic ablation of Trp53 in Dgcr8-/- PSCs enables neural differentiation, while activation of p53 by the MDM2 inhibitor nutlin-3a in wild-type ESCs inhibits neural differentiation. Together, we demonstrate that a major function of miRNAs in neural differentiation is suppression of p53 and that modest activation of p53 blocks neural differentiation of miRNA-deficient PSCs.
Elevated p53 Activities Restrict Differentiation Potential of MicroRNA-Deficient Pluripotent Stem Cells.
Specimen part
View SamplesSeasonal influenza outbreaks and recurrent influenza pandemics present major challenges to public health. By studying immunological responses to influenza in different host species, it may be possible to discover common mechanisms of susceptibility in response to various influenza strains. This could lead to novel therapeutic targets with wide clinical application. Using a mouse-adapted strain of influenza (A/HK/1/68-MA20 [H3N2]), we produced a mouse model of severe influenza (p-flu) that reproduces the hallmark high viral load and overexpression of cytokines associated with susceptibility to p-flu in humans. We mapped genetic determinants of the host response using a panel of 29 closely related mouse strains (AcB/BcA panel of recombinant congenic strains) created from influenza-susceptible A/J and influenza-resistant C57BL/6J (B6) mice. Combined clinical quantitative trait loci (cQTL) and lung expression QTL (eQTL) mapping identified candidate genes for two sex-specific QTLs on chromosomes 2 and 17. The former includes the previously described Hc gene, a deficit of which is associated with the susceptibility phenotype in females. The latter includes the phospholipase gene Pla2g7 and Tnfrsf21, a member of the tumor necrosis factor receptor superfamily. Confirmation of the gene underlying the chromosome 17 QTL may reveal new strategies for influenza treatment.
Mapping of clinical and expression quantitative trait loci in a sex-dependent effect of host susceptibility to mouse-adapted influenza H3N2/HK/1/68.
Age, 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
View SamplesIn the urinary tract, smooth muscle (SM) is present in the renal pelvis, the ureter, the bladder and the urethra and plays a crucial role in the functional and structural integrity of these organs. In Tshz3 mutant ureters the myogenic program is not activated in the proximal region due to the absence of expression of myocardin (Myocd), a key regulator of SM differentiation. We set out to characterize TSHZ3-dependent mechanisms that participate to the process of ureteric smooth muscle cells (SMC) differentiation.
The tiptop/teashirt genes regulate cell differentiation and renal physiology in Drosophila.
Specimen part
View SamplesTo study the function of BAF250 during ES cell self renewal and differentiation
ES cell pluripotency and germ-layer formation require the SWI/SNF chromatin remodeling component BAF250a.
No sample metadata fields
View SamplesMicroRNAs 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.
No sample metadata fields
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.
No sample metadata fields
View SamplesThe fragile X mental retardation protein FMRP is an RNA binding protein that regulates translation of its bound mRNAs through incompletely defined mechanisms. FMRP has been linked to the microRNA pathway and we show here that it is associated with MOV10, a putative helicase that is also associated with the microRNA pathway. We show that FMRP associates with MOV10 in an RNA-dependent manner and facilitates MOV10-association with RNAs in brain. We identified the RNA sequences recognized by MOV10 using iCLIP and found an increased number of G-quadruplexes in the CLIP sites. We provide evidence that MOV10 facilitates microRNA-mediated translation regulation and also has the novel role of increasing the expression of a subset of RNAs by sterically hindering Argonaute2 association. In summary, we have identified a new mechanism for FMRP-mediated translational regulation through its association with MOV10. Overall design: Comparison of MOV10 siRNA knockdown, irrelevant siRNA control and MOV10 overexpression on total RNA levels
MOV10 and FMRP regulate AGO2 association with microRNA recognition elements.
Specimen part, Cell line, Treatment, Subject
View SamplesUsing the iCLIP protocol we have identified the cellular RNA entities that are bound by MOV10. We report the location and sequence of the MOV10 binding region on each RNA entity. Overall design: To identify the RNAs that bound MOV10, we UV-cross-linked HEK293F cells and immunoprecipitated with an irrelevant antibody (ir or "control") followed by a MOV10-specific antibody (MOV10) to isolate associated RNAs after stringent washing.
MOV10 and FMRP regulate AGO2 association with microRNA recognition elements.
No sample metadata fields
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.
No sample metadata fields
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