The DNA-binding protein, Ikaros, functions as a potent tumor suppressor and hematopoietic regulator. However, the mechanisms by which Ikaros functions in the nucleus remain largely undefined, due in part to its atypical DNA-binding properties and partnership with the poorly understood Mi-2/NuRD complex. In this study, we extended our analysis of thymocyte development and lymphomagenesis in a mouse strain containing a specific deletion of Ikaros zinc finger 4, which exhibits a select subset of abnormalities observed in Ikaros null mice. By examining thymopoiesis in vivo and in vitro, numerous abnormalities were observed. RNA-sequencing revealed that each developmental stage is characterized by mis-regulation of a limited number of genes, with a strong preference for genes modulated in a stage-specific manner. Strikingly, individual genes and pathways rarely exhibited Ikaros-dependence at all developmental stages. Instead, the most consistent feature of aberrantly expressed genes was a reduced magnitude of expression level change during a developmental transition. These results and others suggest that Ikaros may not be a dedicated and consistent activator or repressor of a defined set of genes. Instead, its primary function may be to support the dynamic range of gene expression changes during developmental transitions via atypical molecular mechanisms that remain undefined. Overall design: RNA-Seq of T cells at varying developmental stages and T cells expressing activated Notch in WT and Ikzf1-dF4/dF4 mutant backgrounds
Regulation of gene expression dynamics during developmental transitions by the Ikaros transcription factor.
No sample metadata fields
View SamplesThe C2H2 zinc finger is the most prevalent DNA-binding motif in the mammalian proteome, with DNA-binding domains usually containing more tandem fingers than are needed for stable sequence-specific DNA recognition. To examine the reason for the frequent presence of multiple zinc fingers, we generated mice lacking finger 1 or finger 4 of the 4-finger DNA-binding domain of Ikaros, a critical regulator of lymphopoiesis and leukemogenesis. Each mutant strain exhibited a specific subset of the phenotypes observed with Ikaros null mice. Of particular relevance, fingers 1 and 4 contributed to distinct stages of B- and T-cell development and finger 4 was selectively required for tumor suppression in thymocytes and in a new model of BCR-ABL+ acute lymphoblastic leukemia. These results, combined with transcriptome profiling (this GEO submission: RNA-Seg of whole thymus from wt and the two ZnF mutants), reveal that different subsets of fingers within multi-finger transcription factors can regulate distinct target genes and biological functions, and they demonstrate that selective mutagenesis can facilitate efforts to elucidate the functions and mechanisms of action of this prevalent class of factors. Overall design: Ikaros RNA-Seq from double positive thymocytes comparing wt (n=2), Ikaros-ZnF1-/- mutant (n=2) and Ikaros-ZnF4-/- mutant (n=2)
Selective regulation of lymphopoiesis and leukemogenesis by individual zinc fingers of Ikaros.
Sex, Age, Specimen part, Cell line, Subject
View SamplesThe C2H2 zinc finger is the most prevalent DNA-binding motif in the mammalian proteome, with DNA-binding domains usually containing more tandem fingers than are needed for stable sequence-specific DNA recognition. To examine the reason for the frequent presence of multiple zinc fingers, we generated mice lacking finger 1 or finger 4 of the 4-finger DNA-binding domain of Ikaros, a critical regulator of lymphopoiesis and leukemogenesis. Each mutant strain exhibited a specific subset of the phenotypes observed with Ikaros null mice. Of particular relevance, fingers 1 and 4 contributed to distinct stages of B- and T-cell development and finger 4 was selectively required for tumor suppression in thymocytes and in a new model of BCR-ABL+ acute lymphoblastic leukemia. These results, combined with transcriptome profiling (this GEO submission: RNA-Seg of whole thymus from wt and the two ZnF mutants), reveal that different subsets of fingers within multi-finger transcription factors can regulate distinct target genes and biological functions, and they demonstrate that selective mutagenesis can facilitate efforts to elucidate the functions and mechanisms of action of this prevalent class of factors. Overall design: RNA-Seq from sorted primary proB cell Hardy Fractions B and C+C'', comparing wt, Ikaros-ZnF1-/- mutant and Ikaros-ZnF4-/- mutant.
Selective regulation of lymphopoiesis and leukemogenesis by individual zinc fingers of Ikaros.
Specimen part, Cell line, Subject
View SamplesThe transcription factor STAT5 plays a critical role in B cell acute lymphoblastic leukemia (B-ALL). How STAT5 mediates this effect is unclear. Here we demonstrate that STAT5 activation cooperates with defects in the pre-BCR signaling components encoded by Blnk, Btk, Prkcb, Nfkb1, and Ikzf1 to initiate B-ALL. STAT5 antagonizes NF-B and IKAROS by opposing regulation of shared target genes. STAT5 binding was enriched at super-enhancers, which were associated with an opposing network of transcription factors, including PAX5, EBF1, PU.1, IRF4, and IKAROS. Patients with high ratios of active STAT5 to NF-B or IKAROS have more aggressive disease. Our studies illustrate that an imbalance of two opposing transcriptional programs drive B-ALL, and suggest that restoring the balance of these pathways may inhibit B-ALL.
Antagonism of B cell enhancer networks by STAT5 drives leukemia and poor patient survival.
No sample metadata fields
View SamplesHuman subjects were randomized for treatment with a GnRH-analogue, Goserelin, which suppresses endogenous testosterone or placebo for 12 weeks. Strength training was performed during the last 8 weeks. The suppression of testosterone resulted in an attenuation of the normal muscle adaptation to strength training (increased muscle mass and strength). To identify molecular signals involved in the response to testosterone levels, biopsies were obtained 4 hours after the last training session and gene expression compared with Affymetrix 3' microarrays. This timepoint should capture goserelin effect on both constitutive expression, training induced changes as well as acute exercise induced (4 hours) differences in mRNA levels.
The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels.
Sex, Age, Specimen part, Treatment
View SamplesExisting controversy regarding the importance of AMP-activated protein kinase (AMPK) in fatty acid (FA) oxidation in skeletal muscle with contraction/exercise may to some extent pertain to redundant AMPK1 signaling. Using a mouse model lacking both AMPK1 and -2 in skeletal muscle specifically (mdKO) we hypothesized that FA utilization would be impaired in skeletal muscle. Calorimetric analysis showed a similar respiratory exchange ratio (RER) of AMPK WT and mdKO mice when fed normal chow, a high fat diet or with prolonged fasting. Though, in vivo treadmill exercise at the same relative intensity induced a higher RER in mdKO mice compared to WT (WT=0.81; mdKO=0.87; p<0.01) indicating a decreased utilization of FA. Ex vivo incubation of soleus muscle revealed that basal and contraction-induced FA oxidation was impaired in mdKO mice, suggesting that the increased RER during in vivo running exercise originated from decreased skeletal muscle FA oxidation. A decreased muscle protein expression of CD36 and FABPpm (by 17-40%) together with abolishment of TBC1D1 Ser237 phosphorylation in mdKO mice, may result in lower FA transport capacity and FA transport protein translocation to sarcolemma, respectively. In summary this study shows that the catalytically active AMPK subunits are required for normal stimulation of FA utilization during exercise and contractions.
AMPKα is critical for enhancing skeletal muscle fatty acid utilization during in vivo exercise in mice.
Specimen part
View SamplesTo examine the effect of seminal fluid on the whole genome expression profile of endometrial tissue following mating, RNA was extracted from endometrial tissue collected 8 h after CBAF1 females were mated with intact Balb/c males and compared to RNA from endometrial tissue of females mated with seminal fluid deficient SVX/VAS Balb/c males. This comparison controlled for ovarian hormone status, exposure to the male and mating activity, and the neuroendocrine response to cervical and vaginal stimulus at mating, so that changes in endometrial gene expression could be attributed specifically to contact with seminal fluid. The endometrial RNA from n=16 individual females was pooled into four independent biological replicates per treatment group (n=4 endometrial samples per replicate) and expression profiles were analyzed by Affymetrix microarray. Seminal fluid exposure induced a clear difference in the profile of genes expressed in the endometrium with a total of 335 genes were differentially regulated with a fold-change greater than 1.5 and p<0.05. Of these, 190 genes were upregulated and 145 genes were downregulated following contact with seminal fluid. Bioinformatics analysis revealed TLR4 signaling as a strongly predicted upstream regulator activated by the differentially expressed genes.Additional experiments confirmed the role of TLR4 with the absence of TLR4 in TLR4 null mice resulting in a failure for seminal fluid to induce endometrial Csf3, Cxcl2, Il6 and Tnf expression. This study provides evidence that TLR4 contributes to seminal fluid modulation of the periconception immune environment. Activation of TLR4 signaling by microbial or endogenous components of seminal fluid is thus implicated as a key element of the female tract response to seminal fluid at the outset of pregnancy in mice.
TLR4 Signaling Is a Major Mediator of the Female Tract Response to Seminal Fluid in Mice.
Sex, Specimen part, Time
View SamplesThe protease activity of the paracaspase MALT1 plays an important role in antigen receptor-mediated lymphocyte activation by controlling the activity of the transcription factor NF-kB and is thus essential for the expression of inflammatory target genes.
MALT1 Protease Activity Controls the Expression of Inflammatory Genes in Keratinocytes upon Zymosan Stimulation.
Treatment
View SamplesMaternal IL10 deficiency elevates susceptibility to fetal loss induced by the model Toll-like receptor agonist lipopolysaccharide, but the mechanisms are not well elucidated. Here we show that Il10 null mutant (Il10-/-) mice exhibit altered local T cell responses in pregnancy, exhibiting pronounced hyperplasia in para-aortic lymph nodes draining the uterus with >6-fold increased CD4+ and CD8+ T cells compared with wild-type controls. Amongst these CD4+ cells, Foxp3+ Treg cells were substantially enriched, with 11-fold higher numbers at day 9.5 post coitum (pc). Lymph node hypertrophy in Il10-/- mice was associated with more activated phenotypes in dendritic cells and macrophages, with elevated expression of MHCII, scavenger receptor and CD80. Affymetrix microarray revealed an altered transcriptional profile in Treg cells from pregnant Il10-/- mice, with elevated expression of Ctse (cathepsin E), Il1r1, Il12rb2 and Ifng. In vitro, Il10-/- Treg cells showed reduced steady state Foxp3 expression, and polyclonal stimulation caused greater loss of Foxp3 and reduced capacity to suppress IL17 in CD4+Foxp3- T cells. We conclude that despite a substantially expanded Treg cell pool, diminished stability of Treg cells, increased numbers of effector T cells, and altered phenotypes in dendritic cells and macrophages in pregnancy all potentially confer vulnerability to inflammation-induced fetal loss in Il10-/- mice. These findings suggest a pivotal role for IL10 in facilitating robust immune protection of the fetus from inflammatory challenge and suggest IL10 deficiency could contribute to human gestational disorders where altered T cell responses are implicated.
Unstable Foxp3+ regulatory T cells and altered dendritic cells are associated with lipopolysaccharide-induced fetal loss in pregnant interleukin 10-deficient mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
RNA-stabilized whole blood samples but not peripheral blood mononuclear cells can be stored for prolonged time periods prior to transcriptome analysis.
Sex, Age, Specimen part, Time
View Samples