Project description:Genome-wide analysis of Jarid2, Suz12, and c-Maf binding and H3K27me3 profiling in miR-155 KO and WT Th17 performed by ChIP-seq. We found that Jarid2 and c-Maf is differentially expressed in absence of miR-155 and they compete for binding to the Il22 promoter. We highlight targets of Jarid2 and Suz12 in miR-155 KO Th17 cells that are epigenetically silenced by increased H3K27me3 status. Furthermore, genome-wide analysis through Suz12 ChIP-exo in WT and Jarid2fl/fl;CD4cre Th17 reveals defects in PRC2 recruitment in abscence of Jarid2 that results in derepression of genes in Th17 cells. Thus, one main function of miR-155 is to curb epigenetic silencing by targeting Jarid2. Examination of Jarid2, Suz12, c-Maf binding and H3K27me3 changes in miR-155 KO and WT Th17.
Project description:Genome-wide analysis of Jarid2, Suz12, and c-Maf binding and H3K27me3 profiling in miR-155 KO and WT Th17 performed by ChIP-seq. We found that Jarid2 and c-Maf is differentially expressed in absence of miR-155 and they compete for binding to the Il22 promoter. We highlight targets of Jarid2 and Suz12 in miR-155 KO Th17 cells that are epigenetically silenced by increased H3K27me3 status. Furthermore, genome-wide analysis through Suz12 ChIP-exo in WT and Jarid2fl/fl;CD4cre Th17 reveals defects in PRC2 recruitment in abscence of Jarid2 that results in derepression of genes in Th17 cells. Thus, one main function of miR-155 is to curb epigenetic silencing by targeting Jarid2.
Project description:Genome-wide analysis was performed on microRNA 155+/+ and -/- Th17 cells to determine the differentially expressed transcripts that are regulated by miR-155. We found that Jarid2 was differentially expressed in absence of miR-155 and highlight the mechanism for the silencing of IL-22 by Jarid2 and PRC2 in miR-155-/- Th17 cells.
Project description:We examined the role of miR-155 in differentiated Th17 cells during their induction of Experimental Autoimmune Encephalomyelitis (EAE). Using adoptive transfer experiments, we found that highly purified, MOG antigen specific Th17 cells lacking miR-155 are defective in their capacity to cause EAE. Gene expression profiling of purified miR-155-/- IL-17F+ Th17 cells identified a subset of effector genes that are dependent upon miR-155 for their proper expression through a mechanism involving repression of the transcription factor Ets1. Among the genes reduced in the absence of miR-155 was IL-23R, resulting in miR-155-/- Th17 cells being hypo-responsive to IL-23. Taken together, our study demonstrates a critical role for miR-155 in Th17 cells as they unleash autoimmune inflammation, and finds that this occurs through a signaling network involving miR-155, Ets1 and the clinically relevant IL-23-IL-23R pathway. two biological replicates of miR-155-/- CD4+ IL-17F RFP+ T cells compared to two biological replicates of miR-155+/+CD4+IL-17F RFP+ T cells (as a control).
Project description:We examined the role of miR-155 in differentiated Th17 cells during their induction of Experimental Autoimmune Encephalomyelitis (EAE). Using adoptive transfer experiments, we found that highly purified, MOG antigen specific Th17 cells lacking miR-155 are defective in their capacity to cause EAE. Gene expression profiling of purified miR-155-/- IL-17F+ Th17 cells identified a subset of effector genes that are dependent upon miR-155 for their proper expression through a mechanism involving repression of the transcription factor Ets1. Among the genes reduced in the absence of miR-155 was IL-23R, resulting in miR-155-/- Th17 cells being hypo-responsive to IL-23. Taken together, our study demonstrates a critical role for miR-155 in Th17 cells as they unleash autoimmune inflammation, and finds that this occurs through a signaling network involving miR-155, Ets1 and the clinically relevant IL-23-IL-23R pathway.
Project description:Several studies have indicated an important role for miR-155 in the pathogenesis of B-cell lymphoma. Highly elevated levels of miR-155 were indeed observed in most B-cell lymphomas with the exception of Burkitt lymphoma (BL). However, the molecular mechanisms that underlie the oncogenic role of miR-155 in B-cell lymphoma are not well understood. To identify the miR-155 targets relevant for B-cell lymphoma, we performed RNA immunoprecipitation of Argonaute 2 in Hodgkin lymphoma (HL) cells upon miR-155 inhibition and in BL cells upon ectopic expression of miR-155. We identified 54 miR-155-specific target genes in BL cells and confirmed miR-155 targeting of DET1, NIAM, TRIM32, HOMEZ, PSIP1 and JARID2. Five of these targets are also regulated by endogenous miR-155 in HL cells. Both overexpression of miR-155 and inhibition of expression of the novel miR-155 target gene NIAM increased proliferation of BL cells. In primary B-cell lymphoma NIAM-positive cases have significant lower levels of miR-155 as compared to NIAM-negative cases, suggesting that NIAM is also regulated by miR-155 in primary B-cell lymphoma. Thus, our data indicate an oncogenic role for miR-155 in B-cell lymphoma which involves targeting the tumor suppressor NIAM.
Project description:Several studies have indicated an important role for miR-155 in the pathogenesis of B-cell lymphoma. Highly elevated levels of miR-155 were indeed observed in most B-cell lymphomas with the exception of Burkitt lymphoma (BL). However, the molecular mechanisms that underlie the oncogenic role of miR-155 in B-cell lymphoma are not well understood. To identify the miR-155 targets relevant for B-cell lymphoma, we performed RNA immunoprecipitation of Argonaute 2 in Hodgkin lymphoma (HL) cells upon miR-155 inhibition and in BL cells upon ectopic expression of miR-155. We identified 54 miR-155-specific target genes in BL cells and confirmed miR-155 targeting of DET1, NIAM, TRIM32, HOMEZ, PSIP1 and JARID2. Five of these targets are also regulated by endogenous miR-155 in HL cells. Both overexpression of miR-155 and inhibition of expression of the novel miR-155 target gene NIAM increased proliferation of BL cells. In primary B-cell lymphoma NIAM-positive cases have significant lower levels of miR-155 as compared to NIAM-negative cases, suggesting that NIAM is also regulated by miR-155 in primary B-cell lymphoma. Thus, our data indicate an oncogenic role for miR-155 in B-cell lymphoma which involves targeting the tumor suppressor NIAM.
Project description:Several studies have indicated an important role for miR-155 in the pathogenesis of B-cell lymphoma. Highly elevated levels of miR-155 were indeed observed in most B-cell lymphomas with the exception of Burkitt lymphoma (BL). However, the molecular mechanisms that underlie the oncogenic role of miR-155 in B-cell lymphoma are not well understood. To identify the miR-155 targets relevant for B-cell lymphoma, we performed RNA immunoprecipitation of Argonaute 2 in Hodgkin lymphoma (HL) cells upon miR-155 inhibition and in BL cells upon ectopic expression of miR-155. We identified 54 miR-155-specific target genes in BL cells and confirmed miR-155 targeting of DET1, NIAM, TRIM32, HOMEZ, PSIP1 and JARID2. Five of these targets are also regulated by endogenous miR-155 in HL cells. Both overexpression of miR-155 and inhibition of expression of the novel miR-155 target gene NIAM increased proliferation of BL cells. In primary B-cell lymphoma NIAM-positive cases have significant lower levels of miR-155 as compared to NIAM-negative cases, suggesting that NIAM is also regulated by miR-155 in primary B-cell lymphoma. Thus, our data indicate an oncogenic role for miR-155 in B-cell lymphoma which involves targeting the tumor suppressor NIAM.
Project description:The pro-inflammatory microRNA-155 (miR-155) is highly expressed in the serum and CNS lesions of patients with multiple sclerosis (MS). The whole-body deletion of miR-155 in mice confers resistance to a mouse model of MS, EAE, by reducing the encephalogenic potential of CNS-infiltrating Th17 T cells. However, cell intrinsic roles for miR-155 during EAE have not been formally determined. Here we utilize single-cell RNA sequencing and cell-specific conditional miR-155 knockouts to determine the importance of miR-155 expression in distinct immune cell populations. Time course single-cell sequencing revealed reductions in T cells, macrophages, and dendritic cells in whole-body miR-155 knockout mice compared with wild-type controls at day 21. Deletion of miR-155 in T cells, driven by CD4 cre, reduced disease severity similar to whole-body miR-155 knockouts. CD11c cre-driven deletion of miR-155 in dendritic cells also significantly reduced EAE disease score, with both T cell and dendritic cell-specific knockouts showing a reduction in Th17 T cell infiltration into the CNS. Although miR-155 is highly expressed in infiltrating macrophages during EAE, deletion of miR-155 using LysM cre did not affect disease severity. Taken together, these data show that while miR-155 is highly expressed in most infiltrating immune cells, miR-155 has distinct roles and requirements depending on the cell type. This provides insights into which functionally relevant cell types should be targeted by the next generation of miRNA therapeutics.