Thymic stromal lymphopoietin (TSLP) is a type I cytokine that plays a central role in induction of allergic inflammatory responses. Its principal targets have been reported to be dendritic cells and / or CD4 T cells; epithelial cells are a principal source. We report here the development of a reporter mouse (TSLP-ZsG) in which a ZsGreen (ZsG)-encoding construct has been inserted by recombineering into a bacterial artificial chromosome (BAC) immediately at the translation initiating ATG of TSLP. The expression of ZsG by mice transgenic for the recombinant BAC appears to be a faithful surrogate for TSLP expression, particularly in keratinocytes and medullary thymic epithelials cells (mTECs). A comparison of gene expression in ZsG expressing and ZsG negative mTECs and cortical thymic epithelial cells, which are all ZsG negative, revealed that all three populations can be distinguished from one another. In particular ZsG (and TSLP) expressing mTECs and ZsG- mTECs are separable populations based on gene expression profiling. Little or no expression of ZsG is observed in bone marrow-derived mast cells or basophils or in CD45+ cells infiltrating TSLP/ZsG-expressing skin. Using the TSLP-ZsG reporter mouse, we show that TNFa and IL-4/IL-13 are potent inducers of TSLP expression by keratinocytes and that local activation of Th2 and Th1 cells induces keratinocyte TSLP expression. We suggest that the capacity of TSLP to both induce Th2 differentiation and to be induced by activated Th2 cells raises the possibility that TSLP may be involved in a positive feedback loop to enhance allergic inflammatory conditions.
TSLP expression: analysis with a ZsGreen TSLP reporter mouse.
Specimen part, Treatment
View SamplesGoal of experiment: Identify genes down-regulated between pre- and post-natal stages in mouse dental papillae.
Down-regulated genes in mouse dental papillae and pulp.
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View SamplesMast cells, activated by antigen via the high affinity receptor for IgE (FcRI), release an array of pro-inflammatory mediators that contribute to allergic disorders such as asthma and anaphylaxis. The KIT ligand, stem cell factor (SCF), is critical for mast cell expansion, differentiation and survival, and, under acute conditions, enhances mast cell activation. However, extended SCF exposure in vivo conversely protects against fatal antigen-mediated anaphylaxis. In investigating this dichotomy, we identified a novel mode of regulation of the mast cell activation phenotype through SCF-mediated programming. We found that mouse bone marrow-derived mast cells chronically exposed to SCF displayed a marked attenuation of FcRI-mediated degranulation and cytokine production. The hypo-responsive phenotype was not a consequence of altered signals regulating calcium flux or protein kinase C, but of ineffective cytoskeletal reorganization, with evidence implicating a down-regulation of expression of the Src kinase Hck. Collectively, these findings demonstrate a major role for SCF in the homeostatic control of mast cell activation with potential relevance to mast cell-driven disease and the development of novel approaches for the treatment of allergic disorders.
Stem cell factor programs the mast cell activation phenotype.
Specimen part, Treatment
View SamplesWe describe a novel subset of CD8+ DCs in lymphoid organs of nave mice characterized by expression of the CX3CR1 chemokine receptor. CX3CR1+CD8+ DCs lack hallmarks of classical CD8+ DCs, including IL12 secretion, the capacity to cross-present antigen and their developmental independence of the transcriptional factor BatF3. Gene expression profiling showed that CX3CR1+CD8+ DCs resemble CD8- cDCs. The microarray analysis further revealed a unique plasmacytoid DC (PDC) gene signature of CX3CR1+ CD8+ DCs. A PDC relationship of the cells is further supported by the fact that they harbor characteristic D-J immunoglobulin gene rearrangements and that development of CX3CR1+CD8+ DCs requires E2-2, the critical transcriptional regulator of PDCs. Thus, CX3CR1+ CD8+ DCs represent a unique DC subset, related to but distinct from PDCs.
CX3CR1+ CD8alpha+ dendritic cells are a steady-state population related to plasmacytoid dendritic cells.
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View SamplesTERT is an essential protein component of telomerase, a ribonuclearprotein complex that protects chromosomal ends. Ectopic expression of TERT in mouse skin activates hair follicle stem cells and induces active growth phase of hair cycles, called anagen. This activity of TERT is independent of its reverse transcriptase function, indicating that this is a non-telomeric function of TERT.
TERT promotes epithelial proliferation through transcriptional control of a Myc- and Wnt-related developmental program.
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View SamplesThe genetic mechanism governing the spatial patterning of teeth still remains to be elucidated. Sonic hedgehog (Shh) is one of key signaling molecules involved in the spatial patterning of teeth. By utilizing maternal transfer of 5E1 (an IgG1 monoclonal antibody against Shh protein) through the placenta to block Shh signaling, we investigated the changes in tooth patterning and in gene expression.
Interactions between Shh, Sostdc1 and Wnt signaling and a new feedback loop for spatial patterning of the teeth.
Specimen part, Time
View SamplesGene regulation at the maternal-embryonic transition in the pre-implantation mouse embryo is not well understood. We knock down Ccna2 to establish proof-of-concept that antisense morpholino oligonucleotides can be used to target specific genes. We applied this strategy to study Oct4 and discovered that Oct4 is required prior to blastocyst development. Specifically, gene expression is altered as early as the 2-cell stage in Oct4-knockdown embryos.
A novel and critical role for Oct4 as a regulator of the maternal-embryonic transition.
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View SamplesInterleukin-33 (IL-33) is elevated in afflicted tissues of patients with mast cell-dependent chronic allergic diseases. Based on its acute effects on mouse mast cells (MCs), IL-33 is thought to play a role in the pathogenesis of allergic disease through MC activation. However, the manifestations of chronic IL-33 exposure on human MC function, which best reflect the conditions associated with chronic allergic disease, are unknown. We now find that long-term exposure of human and mouse MCs to IL-33 results in a substantial reduction of MC activation in response to antigen. This reduction required >72 h exposure to IL-33 for onset and 1-2 wk for reversion following IL-33 removal. This hypo-responsive phenotype was determined to be a consequence of MyD88-dependent attenuation of signaling processes necessary for MC activation including antigen-mediated calcium mobilization and cytoskeletal reorganization; potentially as a consequence of down-regulation of the expression of PLCg1 and Hck. These findings suggest that IL-33 may play a protective, rather than a causative role in MC activation under chronic conditions and, furthermore, reveal regulated plasticity in the MC activation phenotype. The ability to down-regulate MC activation in this manner may provide alternative approaches for treatment of MC-driven disease.
IL-33 induces a hyporesponsive phenotype in human and mouse mast cells.
Specimen part, Treatment
View SamplesDN3, DN4 and DP cells were sorted from 3-4 week old WT and mice and subjected to transcriptome analysis
The tumor suppressor Ikaros shapes the repertoire of notch target genes in T cells.
Specimen part
View SamplesUsing EphB2 or the ISC marker Lgr5, we have FACS-purified and profiled intestinal stem cells (ISCs), crypt proliferative progenitors and late transient amplifying cells to define a gene expression program specific for normal ISCs.
The intestinal stem cell signature identifies colorectal cancer stem cells and predicts disease relapse.
Specimen part
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