Project description:During acute viral infections, effector CD8+ T cells differentiate into memory precursors or short-lived terminal effectors. miR-17-92a over-expression skews CD8+ effector cells to the terminal differentiation. We used microarray to identify the genes that are differentially expressed caused by miR-17-92a over-expression. CD8+ T cells from P14 TCR transgenic mice were infected with miR-17-92a-MSCV-IRES-Thy1.1 vector and transfer to C57BL6 recipients. Chimeras were infected with LCMV Armstrong. Thy1.1+ miR-17-92a-MSCV-IRES-Thy1.1 transduced P14 cells and Thy1.1- non-transduced P14 cells were sorted by FACS. RNA was extracted from samples, labeled, and hybridized to Affymetrix microarrays.
Project description:Medulloblastoma is the most common malignant pediatric brain tumor, and mechanisms underlying its development are poorly understood. We identified recurrent amplification of the miR-17/92 polycistron proto-oncogene in 6% of pediatric medulloblastomas by high-resolution single-nucleotide polymorphism genotyping arrays and subsequent interphase fluorescence in situ hybridization on a human medulloblastoma tissue microarray. Profiling the expression of 427 mature microRNAs (miRNA) in a series of 90 primary human medulloblastomas revealed that components of the miR-17/92 polycistron are the most highly up-regulated miRNAs in medulloblastoma. Expression of miR-17/92 was highest in the subgroup of medulloblastomas associated with activation of the sonic hedgehog (Shh) signaling pathway compared with other subgroups of medulloblastoma. Medulloblastomas in which miR-17/92 was up-regulated also had elevated levels of MYC/MYCN expression. Consistent with its regulation by Shh, we observed that Shh treatment of primary cerebellar granule neuron precursors (CGNP), proposed cells of origin for the Shh-associated medulloblastomas, resulted in increased miR-17/92 expression. In CGNPs, the Shh effector N-myc, but not Gli1, induced miR-17/92 expression. Ectopic miR-17/92 expression in CGNPs synergized with exogenous Shh to increase proliferation and also enabled them to proliferate in the absence of Shh. We conclude that miR-17/92 is a positive effector of Shh-mediated proliferation and that aberrant expression/amplification of this miR confers a growth advantage to medulloblastomas.
Project description:Medulloblastoma is the most common malignant pediatric brain tumor, and mechanisms underlying its development are poorly understood. We identified recurrent amplification of the miR-17/92 polycistron proto-oncogene in 6% of pediatric medulloblastomas by high-resolution single-nucleotide polymorphism genotyping arrays and subsequent interphase fluorescence in situ hybridization on a human medulloblastoma tissue microarray. Profiling the expression of 427 mature microRNAs (miRNA) in a series of 90 primary human medulloblastomas revealed that components of the miR-17/92 polycistron are the most highly up-regulated miRNAs in medulloblastoma. Expression of miR-17/92 was highest in the subgroup of medulloblastomas associated with activation of the sonic hedgehog (Shh) signaling pathway compared with other subgroups of medulloblastoma. Medulloblastomas in which miR-17/92 was up-regulated also had elevated levels of MYC/MYCN expression. Consistent with its regulation by Shh, we observed that Shh treatment of primary cerebellar granule neuron precursors (CGNP), proposed cells of origin for the Shh-associated medulloblastomas, resulted in increased miR-17/92 expression. In CGNPs, the Shh effector N-myc, but not Gli1, induced miR-17/92 expression. Ectopic miR-17/92 expression in CGNPs synergized with exogenous Shh to increase proliferation and also enabled them to proliferate in the absence of Shh. We conclude that miR-17/92 is a positive effector of Shh-mediated proliferation and that aberrant expression/amplification of this miR confers a growth advantage to medulloblastomas. A total of 90 primary medulloblastoma specimens were profiled by Affymetrix exon array and gene-level analysis was performed.
Project description:During acute viral infections, effector CD8+ T cells differentiate into memory precursors or short-lived terminal effectors. miR-17-92a over-expression skews CD8+ effector cells to the terminal differentiation. We used microarray to identify the genes that are differentially expressed caused by miR-17-92a over-expression.
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.
2019-06-17 | PXD012610 | Pride
Project description:Temporal expression of miR-17-92a regulates effector and memory CD8+ T cell differentiation
Project description:Neonates often generate incomplete immunity against intracellular pathogens, although the mechanism of this defect is poorly understood. An important question is whether the impaired development of memory CD8+ T cells in neonates is due to an immature priming environment or lymphocyte-intrinsic defects. Here we show that neonatal and adult CD8+ T cells adopted different fates when responding to equal amounts of stimulation in the same host. While adult CD8+ T cells differentiated into a heterogeneous pool of effector and memory cells, neonatal CD8+ T cells preferentially gave rise to short-lived effector cells and exhibited a distinct gene expression profile. Surprisingly, impaired neonatal memory formation was not due to a lack of responsiveness, but instead because neonatal CD8+ T cells expanded more rapidly than adult cells and quickly became terminally differentiated. Collectively, these findings demonstrate that neonatal CD8+ T cells exhibit an imbalance in effector and memory CD8+ T cell differentiation, which impairs the formation of memory CD8+ T cells in early life mRNA profiles of effector CD8+ T cells from neonatal and adult mice
Project description:Neonates are highly susceptible to repeat infection and respond poorly to vaccination; these attributes derive from intrinsic differences between neonatal and adult naïve CD8+ T cells. In contrast to adult cells, naïve neonatal cells exhibit a greatly limited ability to differentiate into memory cells, a fundamental property of their adult counterparts. Here, we describe the role of the miR-29 microRNA in naïve T cells, focusing on age-related differences in miR-29 expression and the consequences of these differences in adult and neonatal cells, from mice and humans. In adults, high expression of miR-29 licenses naïve cells towards eventual memory cell fates; whereas neonatal naïve cells, which lack high expression of miR-29, are predisposed towards effector cell fates in response to an infection. Multiple lines of evidence support this model, including analysis of a mouse model deficient in miR-29, which we examine with adoptive transfer experiments to define the functional consequences of reduction of miR-29, together with genomic assays to define the regulatory impact of miR-29. Adult miR 29 deficient naïve CD8+ T cells cell are primed for activation and therefore secrete elevated levels of cytolytic molecules, and express transcription factors at levels associated with effector cell differentiation; moreover, these cells exhibit an altered CD8+ T cell memory repertoire, akin to that of neonatal CD8+ T cells. Importantly, we use a method that exploits extracellular vesicles as a delivery vehicle with which to modulate levels of miR-29 in neonatal and adult naïve T cells, examining both human and mouse cells. For example, increasing miR 29 expression in mouse naïve neonatal CD8+ T cells significantly improved the memory response during infection, concomitant with alterations to the chromatin landscape characteristic of cells primed for memory differentiation. Delivery of miR-29 antagomirs to human adult naïve CD8+ T cells was sufficient to induce the adult cells to adopt phenotypes and gene expression signatures normally found in cells present in newborns. This study establishes miR-29 as a key conserved regulator in naïve CD8+ T cells, and by adjusting levels of miR-29, has the potential to underlie therapeutic strategies for controlling the balance of effector versus memory fates in human T cells.
Project description:Neonates are highly susceptible to repeat infection and respond poorly to vaccination; these attributes derive from intrinsic differences between neonatal and adult naïve CD8+ T cells. In contrast to adult cells, naïve neonatal cells exhibit a greatly limited ability to differentiate into memory cells, a fundamental property of their adult counterparts. Here, we describe the role of the miR-29 microRNA in naïve T cells, focusing on age-related differences in miR-29 expression and the consequences of these differences in adult and neonatal cells, from mice and humans. In adults, high expression of miR-29 licenses naïve cells towards eventual memory cell fates; whereas neonatal naïve cells, which lack high expression of miR-29, are predisposed towards effector cell fates in response to an infection. Multiple lines of evidence support this model, including analysis of a mouse model deficient in miR-29, which we examine with adoptive transfer experiments to define the functional consequences of reduction of miR-29, together with genomic assays to define the regulatory impact of miR-29. Adult miR 29 deficient naïve CD8+ T cells cell are primed for activation and therefore secrete elevated levels of cytolytic molecules, and express transcription factors at levels associated with effector cell differentiation; moreover, these cells exhibit an altered CD8+ T cell memory repertoire, akin to that of neonatal CD8+ T cells. Importantly, we use a method that exploits extracellular vesicles as a delivery vehicle with which to modulate levels of miR-29 in neonatal and adult naïve T cells, examining both human and mouse cells. For example, increasing miR 29 expression in mouse naïve neonatal CD8+ T cells significantly improved the memory response during infection, concomitant with alterations to the chromatin landscape characteristic of cells primed for memory differentiation. Delivery of miR-29 antagomirs to human adult naïve CD8+ T cells was sufficient to induce the adult cells to adopt phenotypes and gene expression signatures normally found in cells present in newborns. This study establishes miR-29 as a key conserved regulator in naïve CD8+ T cells, and by adjusting levels of miR-29, has the potential to underlie therapeutic strategies for controlling the balance of effector versus memory fates in human T cells.
Project description:Neonates are highly susceptible to repeat infection and respond poorly to vaccination; these attributes derive from intrinsic differences between neonatal and adult naïve CD8+ T cells. In contrast to adult cells, naïve neonatal cells exhibit a greatly limited ability to differentiate into memory cells, a fundamental property of their adult counterparts. Here, we describe the role of the miR-29 microRNA in naïve T cells, focusing on age-related differences in miR-29 expression and the consequences of these differences in adult and neonatal cells, from mice and humans. In adults, high expression of miR-29 licenses naïve cells towards eventual memory cell fates; whereas neonatal naïve cells, which lack high expression of miR-29, are predisposed towards effector cell fates in response to an infection. Multiple lines of evidence support this model, including analysis of a mouse model deficient in miR-29, which we examine with adoptive transfer experiments to define the functional consequences of reduction of miR-29, together with genomic assays to define the regulatory impact of miR-29. Adult miR 29 deficient naïve CD8+ T cells cell are primed for activation and therefore secrete elevated levels of cytolytic molecules, and express transcription factors at levels associated with effector cell differentiation; moreover, these cells exhibit an altered CD8+ T cell memory repertoire, akin to that of neonatal CD8+ T cells. Importantly, we use a method that exploits extracellular vesicles as a delivery vehicle with which to modulate levels of miR-29 in neonatal and adult naïve T cells, examining both human and mouse cells. For example, increasing miR 29 expression in mouse naïve neonatal CD8+ T cells significantly improved the memory response during infection, concomitant with alterations to the chromatin landscape characteristic of cells primed for memory differentiation. Delivery of miR-29 antagomirs to human adult naïve CD8+ T cells was sufficient to induce the adult cells to adopt phenotypes and gene expression signatures normally found in cells present in newborns. This study establishes miR-29 as a key conserved regulator in naïve CD8+ T cells, and by adjusting levels of miR-29, has the potential to underlie therapeutic strategies for controlling the balance of effector versus memory fates in human T cells.