OBJECTIVE: MEIS1, a HOX cofactor, collaborates with multiple HOX and NUP98-HOX fusion proteins to accelerate the onset of acute myeloid leukemia (AML) through largely unknown molecular mechanisms. MATERIALS AND METHODS: To further resolve these mechanisms, we conducted a structure-function analysis of MEIS1 and gene-expression profiling, in the context of NUP98-HOXD13 (ND13) leukemogenesis. RESULTS: We show, in a murine bone marrow transplantation model, that the PBX-interaction domain, the homeodomain, and the C-terminal domain of MEIS1, are all required for leukemogenic collaboration with ND13. In contrast, the N-terminal domain of MEIS1 is dispensable for collaboration with ND13, but is required for Flt3 upregulation, indicating additional roles for MEIS1 in induction of leukemia independent of alterations in Flt3 expression. Gene-expression profiling of a cloned ND13 preleukemic cell line transduced with wild-type or Meis1 mutant forms revealed deregulation of multiple genes, including a set not previously implicated as MEIS1 targets. Chromatin immunoprecipitation revealed the in vivo occupancy of MEIS1 on regulatory sequences of Trib2, Flt3, Dlk1, Ccl3, Ccl4, Pf4, and Rgs1. Furthermore, engineered overexpression of Trib2 complements ND13 to induce AML while Ccl3 potentiates the repopulating ability of ND13. CONCLUSION: This study shows that Meis1-induced leukemogenesis with ND13 can occur in the absence of Flt3 upregulation and reveals the existence of other pathways activated by MEIS1 to promote leukemia.
Linkage of Meis1 leukemogenic activity to multiple downstream effectors including Trib2 and Ccl3.
Specimen part
View SamplesThese data are from the brains (amygdala and hippocampus) of mice originally derived from a cross between C57BL/6J and DBA/2J inbred strains. We used short-term selection to produce outbred mouse lines with differences in contextual fear conditioning, which is a measure of fear learning. We selected for a total of 4 generations. Fear learning differed in the selected lines and this difference was stronger with each successive generation of selection. These mice also showed differences for measures of anxiety-like behavior, but were not different for tests of non-fear motivated learning, suggesting that selection altered alleles that are specifically involved in emotional behaviors. We identified several QTLs for the selection response. We used Affymetrix microarrays to identify differentially expressed genes in the amygdala and hippocampus of mice from the final generation of selection. Amygdala and hippocampus samples were rapidly dissected out of experimentally nave mice f rom each selected line. Three samples were pooled and hybridized to each array. Experimentally nave mice were used because the behavior of the mice can be reliably anticipated due to their lineage. Thus, these gene expression differences are not due to the response to human handling, foot shock or fear-inducing conditioned stimuli. We have a second similar study that focuses on a different selected population that was based on C57BL/6J and A/J mice (see GES4034).
Selection for contextual fear conditioning affects anxiety-like behaviors and gene expression.
No sample metadata fields
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 SamplesEffector cells for adoptive immunotherapy can be generated by in vitro stimulation of nave or memory subsets of CD8+ T cells. While the characteristics of CD8+ T cell subsets are well defined, the heritable influence of those populations on their effector cell progeny is not well understood. We studied effector cells generated from nave or central memory CD8+ T cells and found that they retained distinct gene expression signatures and developmental programs. Effector cells derived from central memory cells tended to retain their CD62L+ phenotype, but also to acquire KLRG1, an indicator of cellular senescence. In contrast, the effector cell progeny of nave cells displayed reduced terminal differentiation, and, following infusion, they displayed greater expansion, cytokine production, and tumor destruction. These data indicate that effector cells retain a gene expression imprint conferred by their nave or central memory progenitors, and they suggest a strategy for enhancing cancer immunotherapy.
Adoptively transferred effector cells derived from naive rather than central memory CD8+ T cells mediate superior antitumor immunity.
Specimen part
View SamplesMethylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of young adult mice treated with a single systemic dose of MAM display DNA damage (O6-methylguanine lesions) that peaks at 48 hours and decline to near-normal levels at 7 days post-treatment. By contrast, at this time, MAM-treated mice lacking the gene encoding the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT), showed persistent O6-methylguanine DNA damage. The DNA damage was linked to cell-signaling pathways that are perturbed in cancer and neurodegenerative disease. These data are consistent with the established carcinogenic and developmental neurotoxic properties of MAM in rodents, and they support the proposal that cancer and neurodegeneration share common signal transduction pathways. They also strengthen the hypothesis that early life exposure to the MAM glucoside cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for medicine and/or food. Exposure to environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimers disease, as well as cancer.
The cycad genotoxin MAM modulates brain cellular pathways involved in neurodegenerative disease and cancer in a DNA damage-linked manner.
Sex, Specimen part, Time
View SamplesWe used microarrays to detail the global programme of gene expression after 4 months of TFEB overexpression in the brain.
Selective clearance of aberrant tau proteins and rescue of neurotoxicity by transcription factor EB.
Specimen part, Treatment
View SamplesGlud1 (glutamate dehydrogenase 1) transgenic mice release more excitatory neurotransmitter glutamate to synaptic cleft throughout lifespan and show signs of accelerated aging.
Transcriptomic responses in mouse brain exposed to chronic excess of the neurotransmitter glutamate.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Developmentally regulated higher-order chromatin interactions orchestrate B cell fate commitment.
Specimen part
View SamplesOrganization of the genome in 3D nuclear-space is known to play a crucial role in regulation of gene expression. However, the chromatin architecture that impinges on the B cell-fate choice of multi-potent progenitors remains unclear. By employing in situ Hi-C, we have identified distinct sets of genomic loci that undergo a developmental switch between permissive and repressive compartments during B-cell fate commitment. Intriguingly, we show that topologically associating domains (TADs) represent co-regulated subunits of chromatin and display considerable structural alterations as a result of changes in the cis-regulatory interaction landscape. The extensive rewiring of cis-regulatory interactions is closely associated with differential gene expression programs. Further, we demonstrate the regulatory role of Ebf1 and its downstream factor, Pax5, in chromatin reorganization and transcription regulation. Together, our studies reveal that alterations in promoter and cis-regulatory interactions underlie changes in higher-order chromatin architecture, which in turn determines cell-identity and cell-type specific gene expression patterns.
Developmentally regulated higher-order chromatin interactions orchestrate B cell fate commitment.
Specimen part
View SamplesOur laboratory wanted to define the transcription profile of aged skeletal muscle. For this reason, we performed a triplicate microarray study on young (3 weeks) and aged (24 months) gatrocnemius muscle from wild-type C57B16 Mice
Transcriptional profiling of skeletal muscle reveals factors that are necessary to maintain satellite cell integrity during ageing.
Sex
View Samples