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 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
View SamplesMechanisms controlling the proliferative activity of neural stem/progenitor cells (NSPCs) play a pivotal role to ensure life-long neurogenesis in the mammalian brain. How metabolic programs are coupled with NSPC activity remains unknown. Here we show that fatty acid synthase (FASN), the key enzyme of de novo lipogenesis, is highly active in adult NSPCs and that conditional deletion of FASN in NSPCs impairs adult neurogenesis. The rate of de novo lipid synthesis and subsequent proliferation of NSPCs is regulated by Spot14, a gene we found to be selectively expressed in low proliferating adult NSPCs. Spot14 reduces the availability of malonyl-CoA, which is an essential substrate for FASN to fuel lipogenesis. Thus, we here identified a functional coupling between the regulation of lipid metabolism and adult NSPC proliferation.
No associated publication
Specimen part
View SamplesWe present a robust serum-free system for the rapid and efficient reprogramming of mouse somatic cells by Oct4, Sox2 and Klf4. The elimination of fetal bovine serum and oncogene c-Myc allowed reprogramming cells to be detected as early as Day 2 and reached greater than 10% of the population at Day 7 post retroviral transduction. The resulting iPS colonies were isolated with high efficiency to establish pluripotent cell lines. Based on this method, we further developed iPS-SF1 as a dedicated reprogramming medium for chemical screening and mechanistic investigations.
Towards an optimized culture medium for the generation of mouse induced pluripotent stem cells.
Specimen part
View SamplesHearts of Myh6-MeCP2 transgenic mice and wildtype littermates were rapidly dissected and flash frozen.
Adrenergic Repression of the Epigenetic Reader MeCP2 Facilitates Cardiac Adaptation in Chronic Heart Failure.
Specimen part
View SamplesTranscriptom analysis of stellate sympathetic ganglia after 8 weeks of cardiac pressure overload caused by transverse aortic constriction.
Sympathetic alpha(2)-adrenoceptors prevent cardiac hypertrophy and fibrosis in mice at baseline but not after chronic pressure overload.
Sex
View SamplesPrecise 5' splice site recognition is essential for both constitutive and regulated pre-mRNA splicing. The U1 snRNP specific protein U1C is involved in this first step of spliceosome assembly and important for stabilizing early splicing complexes. We used an embryonically lethal U1C knockout mutant zebrafish, hi1371, to investigate the potential genomewide role of U1C for splicing regulation. Surprisingly, genomewide RNA-Seq analysis of mutant versus wildtype embryos revealed a large set of specific target genes that changed their alternative splicing patterns in the absence of U1C. In sum, our findings provide evidence for a new role of a general snRNP protein, U1C, as a mediator of alternative splicing regulation.
RNA-Seq analysis in mutant zebrafish reveals role of U1C protein in alternative splicing regulation.
No sample metadata fields
View SamplesDrd2 regulates striatal gene networks.
Suppression of neuroinflammation by astrocytic dopamine D2 receptors via αB-crystallin.
Specimen part
View SamplesL-3,4-dihydroxyphenylalanine (levodopa) treatment is the major pharmacotherapy for Parkinson's disease. However, almost all patients receiving levodopa eventually develop debilitating involuntary movements (dyskinesia). While it is known that striatal spiny projection neurons (SPNs) are involved in the genesis of this movement disorder, the molecular basis of dyskinesia is not understood. In this study, we identify distinct cell-type-specific gene expression changes that occur in sub-classes of SPNs upon induction of a parkinsonian lesion followed by chronic levodopa treatment. We identify several hundred genes whose expression is correlated with levodopa dose, many of which are under the control of AP-1 and ERK signaling. In spite of homeostatic adaptations involving several signaling modulators, AP-1-dependent gene expression remains highly dysregulated in direct pathway SPNs (dSPNs) upon chronic levodopa treatment. We also discuss which molecular pathways are most likely to dampen abnormal dopaminoceptive signaling in spiny projection neurons, hence providing potential targets for antidyskinetic treatments in Parkinson's disease.
Molecular adaptations of striatal spiny projection neurons during levodopa-induced dyskinesia.
Specimen part, Treatment
View SamplesPrions consist of aggregates of abnormal conformers of cellular prion protein (PrPC). They propagate by recruiting host-encoded PrPC although the critical interacting proteins and the reasons for the differences in susceptibility of distinct cell lines and populations are unknown. We derived a lineage of cell lines with markedly differing susceptibilities, unexplained by PrPC expression differences, to identify such factors. We examined the transcriptomes of prion-resistant revertants, isolated from highly susceptible cells, and identified a gene expression signature associated with susceptibility. Several of these genes encode proteins with a role in extracellular matrix (ECM) remodelling, a compartment in which disease-related PrP deposits. Loss-of-function of nine of these genes significantly increased susceptibility. Remarkably, inhibition of fibronectin 1 binding to integrin 8 by RGD peptide inhibited metalloproteinases (MMP)-2/9 whilst increasing prion propagation rates. This indicates that prion replication may be controlled by MMPs at the ECM in an integrin-dependent manner.
Identification of a gene regulatory network associated with prion replication.
Treatment
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