Project description:Follicular helper T cells (TFH cells) are the prototypic helper T cell subset specialized to enable B cells to form germinal centers (GCs) and produce high-affinity antibodies. We found that expression of microRNAs (miRNAs) by T cells was essential for TFH cell differentiation. More specifically, we show that after immunization of mice with protein, the miRNA cluster miR-17~92 was critical for robust differentiation and function of TFH cells in a cell-intrinsic manner that occurred regardless of changes in proliferation. In a viral infection model, miR-17~92 restrained the expression of genes ‘inappropriate’ to the TFH cell subset, including the direct miR-17~92 target Rora. Removal of one Rora allele partially ‘rescued’ the inappropriate gene signature in miR-17~92-deficient TFH cells. Our results identify the miR-17~92 cluster as a critical regulator of T cell–dependent antibody responses, TFH cell differentiation and the fidelity of the TFH cell gene-expression program.
Project description:Follicular helper T cells (TFH cells) are the prototypic helper T cell subset specialized to enable B cells to form germinal centers (GCs) and produce high-affinity antibodies. We found that expression of microRNAs (miRNAs) by T cells was essential for TFH cell differentiation. More specifically, we show that after immunization of mice with protein, the miRNA cluster miR-17~92 was critical for robust differentiation and function of TFH cells in a cell-intrinsic manner that occurred regardless of changes in proliferation. In a viral infection model, miR-17~92 restrained the expression of genes M-bM-^@M-^XinappropriateM-bM-^@M-^Y to the TFH cell subset, including the direct miR-17~92 target Rora. Removal of one Rora allele partially M-bM-^@M-^XrescuedM-bM-^@M-^Y the inappropriate gene signature in miR-17~92-deficient TFH cells. Our results identify the miR-17~92 cluster as a critical regulator of T cellM-bM-^@M-^Sdependent antibody responses, TFH cell differentiation and the fidelity of the TFH cell gene-expression program. Gene expression analysis of control versus miR-17~92 knockout (KO) LCMV-specific SMARTA TFH cells 5.5 days after viral infection.
Project description:A network of gene regulatory factors such as transcription factors and microRNAs establish and maintain the gene expression pattern during hematopoiesis. In this network transcription factors regulate each other and are involved in regulatory loops with microRNAs.The microRNA cluster miR-17-92 is located within the MIR17HG gene and encodes for six mature microRNAs. It is important for hematopoietic differentiation and plays a central role in malignant disease. However, the transcription factors downstream of miR-17-92 are largely elusive and the transcriptional regulation of miR-17-92 is not fully understood. Here we show that miR-17-92 forms a regulatory loop with the transcription factor TAL1. The miR-17-92 cluster inhibits expression of TAL1 and indirectly leads to decreased stability of the TAL1 transcriptional complex. We found that TAL1 and its heterodimerization partner E47 regulate miR-17-92 transcriptionally. Furthermore, miR-17-92 negatively influences erythroid differentiation, a process that depends on gene activation by the TAL1 complex. Our data give example of how transcription factor activity is fine-tuned during normal hematopoiesis. We postulate that disturbance of the regulatory loop between TAL1 and the miR-17-92 cluster could be an important step in cancer development and progression.
Project description:Knockout of the ubiquitously expressed microRNA-17~92 cluster in mice produces a lethal developmental lung defect. We validated the equally widely expressed pro-apoptotic Bim gene as joint target of miR-17~92 cluster members. To study the contribution of miR-17~92:Bim interaction to miR-17~92 overall function, we set up a system of conditional mutagenesis of the Bim 3’UTR. Blocking miR-17~92:Bim interaction early in development phenocopied the lethal lung phenotype of miR-17~92 ablation. Thus, despite hundreds of overall predicted targets vital miRNA functions can be mediated by a single target gene.
Project description:The miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells. In this dataset we deposit global mRNA expression data obtained form primary neuroblastoma tumour cells. This data was used to demonstrate negative correlation between TGFB target gene expression and expression of the miR-17-92 cluster.
Project description:The miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells. In this dataset we deposit global mRNA expression data obtained form primary neuroblastoma tumour cells. This data was used to demonstrate negative correlation between TGFB target gene expression and expression of the miR-17-92 cluster. Expression of different TGFB target genes was correlated to miR-17-92 expression using Spearman's Rank statistics in 40 tumours. A correlation heatmap was calculated to visualize the inverse relation between miR-17-92 expression and TGFB target gene expression.
Project description:Knockout of the ubiquitously expressed microRNA-17~92 cluster in mice produces a lethal developmental defect and blocked B lymphopoiesis. We validated the equally widely expressed Bcl2l11 gene as joint target of miR-17~92 cluster members. Bcl2l11 encodes the pro-apoptotic protein BIM, central to life-death decisions in most mammalian cells. To study the contribution of miR-17~92:Bim interaction to miR-17~92 overall function, we set up a system of conditional mutagenesis of the Bim 3’UTR in the mouse. Blocking miR-17~92:Bim interaction early in development phenocopied the lethal developmental defect of miR-17~92 ablation. In contrast, hematopoietic and B lineage specific mutagenesis, while selectively compromising B lineage cell fitness, left hematopoietic cell compartments untouched as long as the cells expressed Bim biallelically. Thus, despite hundreds of overall predicted targets vital miRNA functions can be mediated by a single target gene, depending on cellular context and level of target gene expression.
Project description:The generation of myelinating cells in the central nervous system (CNS) requires the initiation of specific gene-expression programs in oligodendrocytes. We reasoned that miRNAs could play an important role in this process by regulating critical developmental genes. Microarray profiling of cultured oligodendrocytes identifies the miR-17~92 family of miRNA cluster as highly enriched miRNAs in oligodendrocytes.We specifically deleted the miR-17~92 cluster in oligodendrocytes using the 2´3´-cyclic nucleotide 3´-phosphodiesterase (CNP)-Cre mice. Absence of miR-17~92 leads to a reduction of oligodendrocyte number in vivo and we find that the expression of these miRNAs in primary cultures of oligodendrocytes promotes cell proliferation by influencing Akt signalling. Together, these results suggest that the miRNA pathway is essential in determining oligodendroglial cell number and that the miR-17~92 cluster is crucial in this process.
Project description:The generation of myelinating cells in the central nervous system (CNS) requires the initiation of specific gene-expression programs in oligodendrocytes. We reasoned that miRNAs could play an important role in this process by regulating critical developmental genes. Microarray profiling of cultured oligodendrocytes identifies the miR-17~92 family of miRNA cluster as highly enriched miRNAs in oligodendrocytes. We specifically deleted the miR-17~92 cluster in oligodendrocytes using the 2´3´-cyclic nucleotide 3´-phosphodiesterase (CNP)-Cre mice. Absence of miR-17~92 leads to a reduction of oligodendrocyte number in vivo and we find that the expression of these miRNAs in primary cultures of oligodendrocytes promotes cell proliferation by influencing Akt signalling. Together, these results suggest that the miRNA pathway is essential in determining oligodendroglial cell number and that the miR-17~92 cluster is crucial in this process.
Project description:The generation of myelinating cells in the central nervous system (CNS) requires the initiation of specific gene-expression programs in oligodendrocytes. We reasoned that miRNAs could play an important role in this process by regulating critical developmental genes. Microarray profiling of cultured oligodendrocytes identifies the miR-17~92 family of miRNA cluster as highly enriched miRNAs in oligodendrocytes.We specifically deleted the miR-17~92 cluster in oligodendrocytes using the 2´3´-cyclic nucleotide 3´-phosphodiesterase (CNP)-Cre mice. Absence of miR-17~92 leads to a reduction of oligodendrocyte number in vivo and we find that the expression of these miRNAs in primary cultures of oligodendrocytes promotes cell proliferation by influencing Akt signalling. Together, these results suggest that the miRNA pathway is essential in determining oligodendroglial cell number and that the miR-17~92 cluster is crucial in this process.