The etiology of autoimmune hepatitis is poorly understood but likely involves Th1 cells producing IFN-. BALB/c background TGF-1-/- mice rapidly develop fulminant Th1-mediated autoimmune hepatitis. Our aims are to profile liver gene expression in TGF-1-/- mice, to identify gene expression pathways dependent on IFN- as possible targets for rational therapy, and to test potential targets directly in vivo in mice.
The role of Ifng in alterations in liver gene expression in a mouse model of fulminant autoimmune hepatitis.
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View SamplesBackground: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids.
Activation of sterol-response element-binding proteins (SREBP) in alveolar type II cells enhances lipogenesis causing pulmonary lipotoxicity.
Specimen part
View SamplesDeletion of the gene encoding Foxa2, a winged helix transcription factor selectively expressed in respiratory epithelial cells, caused spontaneous pulmonary eosinophilic inflammation and goblet cell metaplasia. Loss of Foxa2 induced the recruitment and activation of myeloid dendritic cells (mDCs) and Th2 cells in the lung, and was associated with the increased production of T helper 2 (Th2) cytokines and chemokines. mRNA microarray analysis demonstrated that deletion of Foxa2 induced the expression of a number of mRNAs regulating pulmonary dendritic cell activation, Th2 mediated inflammation, and goblet cell differentiation. The spontaneous pulmonary inflammation and goblet cell metaplasia caused by loss of Foxa2 was inhibited by treatment of newborn Foxa2/ mice with monoclonal IL-4Ralpha antibody. Expression of Foxa2 in non-ciliated secretory cells (Clara cells) in vivo inhibited goblet cell differentiation induced by pulmonary allergen exposure. The respiratory epithelium plays a central role in the regulation of Th2-mediated inflammation and innate immunity in the developing lung in a process regulated by Foxa2.
Foxa2 programs Th2 cell-mediated innate immunity in the developing lung.
Specimen part
View SamplesEpithelial organs including the lung are known to possess regenerative abilities through activation of endogenous stem cell populations but the molecular pathways regulating stem cell expansion and regeneration are not well understood. Here we show that Gata6 regulates the temporal appearance and number of bronchioalveolar stem cells (BASCs) in the lung leading to the precocious appearance of BASCs and concurrent loss in epithelial differentiation in Gata6 null lung epithelium. This expansion of BASCs is the result of a dramatic increase in canonical Wnt signaling in lung epithelium upon loss of Gata6. Expression of the non-canonical Wnt receptor Fzd2 is down-regulated in Gata6 mutants and increased Fzd2 or decreased -catenin expression rescues, in part, the lung epithelial defects in Gata6 mutants. During lung epithelial regeneration, we show that canonical Wnt signaling is activated in the niche containing BASCs and forced activation of Wnt signaling leads to a dramatic increase in BASC numbers. Moreover, Gata6 is required for proper lung epithelial regeneration and postnatal loss of Gata6 leads to increased BASC expansion and decreased differentiation. Together, these data demonstrate that Gata6 regulated Wnt signaling controls the balance between stem/progenitor expansion and epithelial differentiation required for both lung development and regeneration.
A Gata6-Wnt pathway required for epithelial stem cell development and airway regeneration.
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View SamplesMethyl tert-butyl ether (MTBE) has been shown to target developing vasculature in piscine and mammalian model systems. In the zebrafish, MTBE induces vascular lesions throughout development. These lesions result from exposure to MTBE at an early stage in development (6-somites to Prim-5 stages). During this time period, transcript levels of vegfa, vegfc, and vegfr1 were significantly decreased in embryos exposed to 5 mM MTBE.
Manipulation of the HIF-Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions.
Specimen part
View SamplesAstrogliosis is a hallmark of the response to brain ischemia, comprised of changes in gene expression and morphology. Hsp72 protects from cerebral ischemia, and although several mechanisms of protection have been investigated, effects on astrocyte activation are unknown. To identify potential mechanisms of protection, gene expression was assessed in mice subjected to middle cerebral artery (MCAO) or sham surgery, of either wildtype (WT) or Hsp72-overexpressing (Hsp72Tg) mice. After stroke, both genotypes exhibited genes related to cell death, stress response, and immune response. Furthermore, genes indicative of astrocyte activation, including cytoskeletal proteins and cytokines, were upregulated. To measure astrocyte activation after stroke, detailed histological and morphological analyses were performed in the cortical penumbra after stroke using unbiased stereology. Consistent with other reports, we observed a marked and persistent increase in glial fibrillary acidic protein (GFAP ) as soon as 3 hours after MCAO. In contrast, vimentin immunoreactivity appeared 12-24 hours after stroke, peaked at 72 hours, and returned to baseline after 30 days. Surprisingly, no change in overall astrocyte number was observed based on glutamine synthetase (GS) immunoreactivity. To determine if Hsp72Tg mice exhibited altered astrocyte activation compared to WT controls, morphological evaluation by fractal analysis was used. Overexpression of Hsp72 reduced astrocyte cell area, arbor area, and to a lesser extent fractal dimension, 72 hours following stroke. In conclusion, in vivo overexpression of Hsp72 alters gene expression following stroke, including genes involved in astrocyte activation, and decreases astrocyte activation acutely following MCAO. Thus, modulation of astrogliosis may be a neuroprotective mechanism exerted by Hsp72 after ischemia.
Effects of heat shock protein 72 (Hsp72) on evolution of astrocyte activation following stroke in the mouse.
Sex, Treatment
View SamplesEfficient and sustained knockdown of DNMT1 transcript and protein was achieved using a consecutive transfection protocol in the mouse pituitary adenoma cell line, AtT-20. Genome wide microarray analysis identified 91 transcripts that were significantly differentially expressed relative to cells treated with a non-targeting control.
Genome-wide analysis in a murine Dnmt1 knockdown model identifies epigenetically silenced genes in primary human pituitary tumors.
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View SamplesSV40 large T antigen (TAg) contributes to cell transformation, in part, by targeting two well characterized tumor suppressors, pRb and p53. TAg expression affects the transcriptional circuits controlled by Rb and by p53. We have performed a microarray analysis to examine the global change in gene expression induced by wild-type TAg and TAg-mutants, in an effort to link changes in gene expression to specific transforming functions. For this analysis we have used enterocytes from the mouse small intestine expressing TAg. Expression of TAg in the mouse intestine results in hyperplasia and dysplasia. Our analysis indicates that practically all gene expression regulated by TAg in enterocytes is dependent upon its binding and inactivation of the Rb-family proteins.
Simian virus 40 T-antigen-mediated gene regulation in enterocytes is controlled primarily by the Rb-E2F pathway.
Sex, Age, Specimen part
View SamplesThe presence of unspliced transcripts in hematopoietic stem cells (HSCs) and the proposed association of CREBBP with the constitutive production of unspliced RNA and with pre-mRNA processing prompted us to examine more closely an anomaly we had noted in microarray-based gene expression studies but had previously attributed to experimental noise. We noticed that more than half of the probe sets down-regulated in Crebbp+/- fetal liver HSCs (FLHSCs) relative to wild-type (WT) mapped entirely within introns, rather than detecting exonic or spliced sequences. We therefore set out to test whether this might be evidence that reduced CREBBP levels selectively alter the generation of full-length, unspliced pre-mRNA. We also asked whether this process might be associated with differentiation since self-renewal and lineage commitment are the both responses for which HSCs are primed.
Inactivation of a single copy of Crebbp selectively alters pre-mRNA processing in mouse hematopoietic stem cells.
Specimen part
View SamplesCumulus-oocyte complexes were isolated a seperate time-points to generate temporal complexes. Targets from two biological replicates at each time point (0h, 8h, 16h post-hCG treatment) were generated and the expression profiles were determined using Affymetrix GeneChip Mouse Genome 430 2.0 Arrays. Comparisons between the sample groups allow the identification of genes with temporal expression patterns.
Gene expression profiles of cumulus cell oocyte complexes during ovulation reveal cumulus cells express neuronal and immune-related genes: does this expand their role in the ovulation process?
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