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:Germinal center (GC) reaction in the lymphoid organs is a pivotal process for humoral immune response. The miR-17~92 family miRNAs have been demonstrated that regulate TFH cell differentiation, GC reaction and antibody response. However, whether they may also have functions in B cell activation and differentiation in GC reaction remain largely unknown. Here we show that mice with deletion of miR-17~92 in B cells exhibited reduced GC B cell formation and profound impaired plasma cell (PC) differentiation as well as decreased antibody response upon protein antigen immunization or chronic LMCV infection. In an in vitro plasma cell differentiation (iGCB) system, we found that miR-17~92 deficiency results in markedly decreased in vitro plasma cell (iPC) differentiation and defective NFB activation. Moreover, we developed and performed a screen by CRISPR/small guide (sg) RNA-mediated gene editing among the target genes of miR-17~92 in iGCB culture system. Intriguingly, Socs3 deletion substantially restored iPC differentiation and NFB activation in miR-17~92 deficient B cells, suggesting that Socs3 acts as a negative regulator of NFκB pathway involved in the regulation of iPC differentiation by miR-17~92. However, IL-21-induced STAT3 activation was not affected by miR-17~92 deficiency during iPC differentiation. Mechanistically, Socs3 interacts with MAP3K14 (NIK) and that promotes the ubiquitination of NIK and subsequent proteasome-mediated degradation of NIK, thereby leading to inhibition of the processing of p100 in non-canonical NFκB pathway and PC differentiation.
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:miR-17 from the miR-17-92 cluster regulate activation-induced cell death in T cells and modulate inducible regulatory T cell differentiation. We used microarrays to detail the global program of gene expression modulated by miR-17 and aim to identify the potential targets of miR-17. CD4 T cells from wild type or miR-17-92 deficient mice were activated and transduced with empty vector or that overexpressing miR-17. Potential targets of miR-17 should be upregulated in miR-17-92 deficient CD4 T cells compared to wild type CD4 T cells, and downregulated when miR-17 were reintroduced into the miR-17-92 deficient T cells.
Project description:Adult beta cells in the pancreas are the sole source of insulin in our body. Beta cell loss or increased demand for insulin, impose metabolic challenges because adult beta cells are generally quiescent and infrequently re-enter the cell division cycle. miR-17-92/106b is a family of proto-oncogene microRNAs, that regulate proliferation in normal tissues and in cancer. Here, we employ mouse genetics to demonstrate a critical role for miR-17-92/106b in glucose homeostasis and in controlling insulin secretion. Mass spectrometry analysis was performed on miR-17-92LoxP/LoxP;106-25-/- MEF lysate, without or with CRE-Adenovirus. miR-17-92LoxP/LoxP;106-25+/+ MEFs with GFP-Adenovirus served as controls. We demonstrate that miR-17-92/106b regulate the adult beta cell mitotic checkpoint and that miR-17-92/106b deficiency results in reduction in beta cell mass in-vivo. Furthermore, protein kinase A (PKA) is a new relevant molecular pathway downstream of miR-17-92/106b in control of adult beta cell division and glucose homeostasis. Therefore, contributes to the understanding of proto-oncogene miRNAs in the normal, untransformed endocrine pancreas, and illustrates new genetic means for regulation of beta cell mitosis and function by non-coding RNAs.
Project description:The miR-17-92 cluster targets mRNAs involved in distinct pathways which either promote or inhibit tumor progression. However, the cellular and molecular mechanisms underlying miR-17~92 cluster mediated pro- or anti- tumorigenic effects has not been studied. In this study, we found that inhibition of colon cancer progression is dictated by quantitatively controlling expression of the miR-17~92 cluster. To identify molecular mechanisms giving rise to the different growth/metastasis patterns, we profiled gene expression in miR-Ctrl, miR-17~92Med and miR-17~92Hi cells using Affymetrix Murine GeneST Arrays.
Project description:The deletion of a single miRNA cluster, miR-17~92, is sufficient to induce primary sex reversal in XY mice. The expression of the testis determining gene, Sry, is delayed in embryonic XY miR-17~92 knockout gonads, which immediately activate the ovarian genetic program. Single cell RNA-seq analysis shows that Sertoli cell differentiation is highly reduced, delayed and unable to trigger testis differentiation. Consistent with the well-known role of miRNAs in gene regulation, the expression of target genes of miR-17~92 is not stabilized in XY mutant gonads at E11.5, affecting, in turn, the fine regulation of large gene networks involved in mammalian sex determination. Our results reveal that the miR-17~92 cluster is a novel sex-determining factor that modulates several gene networks required for accurate timing of Sry expression and Sertoli cell differentiation during testis determination and early differentiation. bulk RNA-seq, single cell RNA-seq as well as IF and other characterizations of a transgenic mice for miR-17~92 cluster
Project description:Medulloblastomas (MBs) are the most common brain tumors in children. Some are thought to originate from cerebellar granule neuron progenitors (GNPs) that fail to undergo normal cell cycle exit and differentiation. Since microRNAs regulate numerous aspects of cellular physiology and development, we reasoned that alterations in miRNA expression might contribute to MB. We tested this hypothesis using two spontaneous mouse MB models with specific initiating mutations, Ink4c-/-; Ptch1+/- and Ink4c-/-; p53-/-. We found that 26 miRNAs showed increased expression and 24 miRNAs showed decreased expression in proliferating mouse GNPs and MBs relative to mature mouse cerebellum, regardless of genotype. Among the 26 overexpressed miRNAs, nine were encoded by the miR-17~92 cluster family, a group of microRNAs implicated as oncogenes in several tumor types. Analysis of human MBs demonstrated that three miR-17~92 cluster miRNAs (miR-92, miR-19a and miR-20) were also overexpressed in human MBs with a constitutively activated SHH signaling pathway, but not in other forms of the disease. To test whether the miR-17~92 cluster could promote MB formation, we enforced expression of these miRNAs in GNPs isolated from cerebella of postnatal (P) day P6 Ink4c-/-; Ptch1+/- mice. These, but not similarly engineered cells from Ink4c-/-; p53-/- mice, formed MBs in orthotopic transplants with complete penetrance. Interestingly, orthotopic mouse tumors ectopically expressing miR-17~92 lost expression of the wild-type Ptch1 allele. Our findings suggest a functional collaboration between the miR-17~92 cluster and the SHH signaling pathway in the development of MBs in mouse and man.
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:The deletion of a single miRNA cluster, miR-17~92, is sufficient to induce primary sex reversal in XY mice. The expression of the testis determining gene, Sry, is delayed in embryonic XY miR-17~92 knockout gonads, which immediately activate the ovarian genetic program. Single cell RNA-seq analysis shows that Sertoli cell differentiation is highly reduced, delayed and unable to trigger testis differentiation. Consistent with the well-known role of miRNAs in gene regulation, the expression of target genes of miR-17~92 is not stabilized in XY mutant gonads at E11.5, affecting, in turn, the fine regulation of large gene networks involved in mammalian sex determination. Our results reveal that the miR-17~92 cluster is a novel sex-determining factor that modulates several gene networks required for accurate timing of Sry expression and Sertoli cell differentiation during testis determination and early differentiation.