To study the development and function of “natural-arising” T regulatory (nTreg) cells, we developed a novel nTreg model on pure nonobese diabetic background using epigenetic reprogramming via somatic cell nuclear transfer. On RAG1-deficient background, we found that monoclonal FoxP3+ CD4+ Treg cells developed in the thymus in the absence of other T cells. Adoptive transfer experiments revealed that the thymic niche is not a limiting factor in nTreg development. In addition, we showed that the T-cell receptor (TCR) ß-chain of our nTreg model was not only sufficient to bias T-cell development toward the CD4 lineage, but we also demonstrated that this TCR ß-chain was able to provide stronger TCR signals. This TCR-ß–driven mechanism would thus unify former per se contradicting hypotheses of TCR-dependent and -independent nTreg development. Strikingly, peripheral FoxP3- CD4+ T cells expressing the same TCR as this somatic cell nuclear transfer nTreg model had a reduced capability to differentiate into Th1 cells but were poised to differentiate better into induced nTreg cells, both in vitro and in vivo, representing a novel peripheral precursor subset of nTreg cells to which we refer to as pre-nTreg cells. Overall design: We performed RNA-Seq analysis to determine the transcriptional differences between monoclonal FoxP3GFP-positive and -negative CD4+ T cells from NOD.TCRab.FoxP3GFP.Rag-/- and compared it with polyclonal FoxP3GFP-positive and -negative CD4+ T cells from NOD.FoxP3GFP mice
Nuclear transfer nTreg model reveals fate-determining TCR-β and novel peripheral nTreg precursors.
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View SamplesUremic media calcification is not only driven by systemic factors such as hyperphosphatemia, but also crticially dependent on vascular smooth muscle cells per se. We hypothesized that the different developmental origins of vscular smooth muscle cells might lead to a heterogeneous susceptibility to develop media calcification.
Heterogeneous susceptibility for uraemic media calcification and concomitant inflammation within the arterial tree.
Specimen part
View SamplesMicroRNAs (miRNAs) post-transcriptionally regulate the expression of thousands of distinct mRNAs. While some regulatory interactions help to maintain basal cellular functions, others are likely relevant in more specific settings, such as response to stress. Here we describe such a role for the mir-290-295 cluster, the dominant miRNA cluster in mouse embryonic stem cells (mESCs). Examination of a target list generated from bioinformatic prediction, as well as expression data following miRNA loss, revealed strong enrichment for apoptotic regulators, two of which we validated directly: Caspase 2, the most highly conserved mammalian caspase, and Ei24, a p53 transcriptional target. Consistent with these predictions, mESCs lacking miRNAs were more likely to initiate apoptosis following genotoxic exposure to gamma irradiation or doxorubicin. Knockdown of either candidate partially rescued this pro-apoptotic phenotype, as did transfection of members of the mir-290-295 cluster. These findings were recapitulated in a specific mir-290-295 deletion line, confirming that they reflect miRNA functions at physiological levels. In contrast to the basal regulatory roles previously identified, the pro-survival phenotype shown here may be most relevant to stressful gestations, where pro-oxidant metabolic states induce DNA damage. Similarly, this cluster may mediate chemotherapeutic resistance in a neoplastic context, making it a useful clinical target.
A latent pro-survival function for the mir-290-295 cluster in mouse embryonic stem cells.
Specimen part
View SamplesPseudomonas aeruginosa is an opportunistic pathogen that causes severe health problems. Despite intensive investigation, many aspects of microbial virulence remain poorly understood. We used a high-throughput, high-content, whole-organism, phenotypic screen to identify small molecules that inhibit P. aeruginosa virulence in C. elegans. Approximately half of the hits were known antimicrobials. A large number of hits were non-antimicrobial bioactive compounds, including the cancer chemotherapeutic 5-fluorouracil. We determined that 5-fluorouracil both transiently inhibits bacterial growth and reduces pyoverdine biosynthesis. Pyoverdine is a siderophore that regulates the expression of several virulence determinants and is critical for pathogenesis in mammals. We show that 5-fluorouridine, a downstream metabolite of 5-fluorouracil, is responsible for inhibiting pyoverdine biosynthesis. We also show that 5-fluorouridine, in contrast to 5-fluorouracil, is a genuine anti-virulent compound, with no bacteriostatic or bacteriocidal activity. To our knowledge, this is the first report utilizing a whole-organism screen to identify novel compounds with antivirulent properties effective against P. aeruginosa.
A High-Content, Phenotypic Screen Identifies Fluorouridine as an Inhibitor of Pyoverdine Biosynthesis and Pseudomonas aeruginosa Virulence.
Specimen part, Treatment
View SamplesAluminum toxicity is one of the major limiting factors for many crops worldwide. The primary symptom of Al toxicity syndrome is the inhibition of root growth, leading to poor water and nutrient absorption. The causes of this inhibition are still elusive, with several biochemical pathways being affected and with a significant variation between species. Most of the work done so far to investigate the genes responsible for Al tolerance used hydroponic culture. Here we evaluated plant responses using soil as substrate, which is a condition closer to the field reality.
Transcriptional profile of maize roots under acid soil growth.
Specimen part
View SamplesPseudomonas aeruginosa is a re-emerging opportunistic pathogen with broad antimicrobial resistance. We have previously reported that the major siderophore pyoverdine from this pathogen disrupts mitochondrial networks and induces a lethal hypoxic response in model host Caernorhabditis elegans. However, the mechanism of such cytotoxicity remained unclear. Here, we demonstrate that pyoverdine translocates into host cells, binding to host ferric iron sources. The reduction of host iron content disrupts mitochondrial function such as NADH oxidation and ATP production and activates mitophagy. This activates a specific immune response that is distinct from colonization-based pathogensis and exposure to downstream pyoverdine effector Exotoxin A. Host response to pyoverdine resembles that of a hypoxic crisis or iron chelator treatment. Furthermore, we demonstrate that pyoverdine is a crucial virulence factor in P. aerguinosa pathogenesis against cystic fibrosis patients; F508 mutation in human CFTR increases susceptibility to pyoverdine-mediated damage.
Pyoverdine, a siderophore from Pseudomonas aeruginosa, translocates into C. elegans, removes iron, and activates a distinct host response.
Specimen part, Treatment
View SamplesIkaros hypomorphic mice (IkL/L) show plasmacytoid dendritic cell (pDC) defects with an absence of pDCs in the peripheral organs and a reduction of pDCs in the bone marrow (BM). Moreover in vitro differentiation of pDC from IkL/L total BM cells is also defective.
Ikaros cooperates with Notch activation and antagonizes TGFβ signaling to promote pDC development.
Treatment
View SamplesTo assess the importance of the Wnt pathway during T cell develoment, we generated a mouse line (R26-cat) in which high levels of active -catenin are maintained throughout T cell development. Young R26-cat mice (6-week-old) show a differentiation block at the CD4+CD8+ DP stage. All R26-cat mice develop T cell leukemias with a DP phenotype at 5-6 months of age.
β-Catenin activation synergizes with Pten loss and Myc overexpression in Notch-independent T-ALL.
Age, Specimen part
View SamplesDeletions at 15q11.2 have been established to increase risk for multiple neurodevelopmental disorders (NDDs) including schizophrenia and epilepsy, yet show variable expressivity between individuals. To investigate the potential role of CYFIP1, a gene within the locus, we carried out knockdown experiments in human neural progenitor cells derived from 15q11.2 neutral induced pluripotent stem cells. Transcriptional profiling and cellular assays support a prominent role for CYFIP1 in cytoskeletal remodeling across all lines examined. Validating the utility of this model for study of disease, genes implicated in schizophrenia and epilepsy but not other disorders or traits unrelated to the deletion, were enriched among mRNAs dysregulated following knockdown. Importantly, and consistent with the variable expressivity of 15q11.2 deletions, the magnitude of disease-related effects varied between donor lines. Towards mechanisms, FMRP targets and synaptic genes were overrepresented among dysregulated mRNAs and as such may contribute to the schizophrenia and epilepsy effects we observe. Further model validation, and new candidate epilepsy genes, comes from machine-learning analyses showing a striking similarity between a subset of dysregulated transcripts and well-established epilepsy genes. Results provide support for an important contribution of CYFIP1 in 15q11.2 mediated risk for NDDs and demonstrate that disease-related biological signatures are evident prior to neuronal differentiation. This new human model of disease will be useful in identifying compounds that could ameliorate outcomes in deletion carriers. Overall design: Investigation of CYFIP1 shRNA knockdown in three neural progenitor cell lines derived from induced pluripotent stem cells (3 control samples and 3 knockdown samples analyzed in each line)
Reduced CYFIP1 in Human Neural Progenitors Results in Dysregulation of Schizophrenia and Epilepsy Gene Networks.
No sample metadata fields
View SamplesWe used microarrays to detail gene expression changes in Hs 294T human melanoma cells after treatment with elesclomol alone, or in combination with paclitaxel, to aide in identifing the mechnism of action of elesclomol.
Elesclomol induces cancer cell apoptosis through oxidative stress.
No sample metadata fields
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