Recent observations about how cells sense amino acids have argued for preeminent roles of mTOR and the stress kinase GCN2 in allowing cells to estimate their amino acid needs. Here we used models of programmed immune microenvironments where helper T cells have to sense how much amino acids are available to engage in antigen-fueled proliferation. Contrary to current models, T cells activate mTOR in the competency phase of the cell cycle regardless of amino acid amounts, GCN2 or surface TCR. Instead, we found T cells use an amino acid sensing system to target IL-2-induced STAT5 phosphorylation at the restriction point of cell cycle commitment. mTOR activity is subsequently reduced and specifically connected to SREBP activation. T cells can be pushed into cycle by increasing IL-2 even when no amino acids are available. Collectively, our studies reveal helper T cells use sequential and distinct pathways to measure local amino acid concentrations.
Proliferating Helper T Cells Require Rictor/mTORC2 Complex to Integrate Signals from Limiting Environmental Amino Acids.
Specimen part, Treatment
View SamplesIntegrins facilitate intercellular movement and communication. Unlike the promiscuous activities of many integrins, 6 integrin is restricted to epithelia and partners exclusively with integrin V to modulate acute lung injury (ALI). Given that ALI is a complication of respiratory infection, we used mice lacking 6 integrin (6 KO) to probe the role of the epithelial layer in controlling the lung microenvironment during infection. We found 6 KO mice were protected from disease caused by influenza and Sendai virus infections. They were also protected from disease caused by Streptococcus pneumoniae infection alone and after prior influenza virus infection, the co-infection representing an often-lethal condition in humans. Resistance in the absence of epithelial 6 integrin was caused by intrinsic priming of the lung microenvironment by type I interferons through a mechanism involving transforming growth factor- regulation. Expression of 6 on epithelia suppresses the production of interferons, providing an advantage to the pathogen. Acute inhibition of 6 function may therefore provide a means to improve outcomes in lung microbial infections.
An Epithelial Integrin Regulates the Amplitude of Protective Lung Interferon Responses against Multiple Respiratory Pathogens.
Specimen part
View SamplesLong term exposure to incretin hormones is known to have salutory effects on beta cell function and viability. While short-term cAMP induction is known to have a signature CREB-CRTC target gene response, the long-term effects of cAMP on beta cell gene expression are less well understood.
mTOR links incretin signaling to HIF induction in pancreatic beta cells.
Cell line, Time
View SamplesThe results of this study indicate that stenotic fibroblasts exhibit an aberrant response to tissue stiffness with reduced MMP activity, leading to a perpetuous vicious circle of ever more fibrosis formation. Altering the microenvironment by LOX inhibition increases MMP activity and decreases ECM contraction, resulting in a potential anti-fibrotic agent for Crohns disease.
Fibrostenotic Phenotype of Myofibroblasts in Crohn's Disease is Dependent on Tissue Stiffness and Reversed by LOX Inhibition.
Sex, Specimen part, Disease, Subject
View SamplesAlmost a quarter of pediatric patients with Acute Lymphoblastic Leukemia (ALL) suffer from relapses. The biological mechanisms underlying therapy response and development of relapses have remained unclear. In an attempt to better understand this phenomenon, we have analyzed 41 matched diagnosis relapse pairs of ALL patients using genomewide expression arrays (82 arrays) on purified leukemic cells. In roughly half of the patients very few differences between diagnosis and relapse samples were found (stable group), suggesting that mostly extra-leukemic factors (e.g., drug distribution, drug metabolism, compliance) contributed to the relapse. Therefore, we focused our further analysis on 20 samples with clear differences in gene expression (skewed group), reasoning that these would allow us to better study the biological mechanisms underlying relapsed ALL. After finding the differences between diagnosis and relapse pairs in this group, we identified four major gene clusters corresponding to several pathways associated with changes in cell cycle, DNA replication, recombination and repair, as well as B cell developmental genes. We also identified cancer genes commonly associated with colon carcinomas and ubiquitination to be upregulated in relapsed ALL. Thus, about half of relapses are due to selection or emergence of a clone with deregulated expression of a genes involved in pathways that regulate B cell signaling, development, cell cycle, cellular division and replication.
Genome-wide expression analysis of paired diagnosis-relapse samples in ALL indicates involvement of pathways related to DNA replication, cell cycle and DNA repair, independent of immune phenotype.
Sex, Specimen part, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin.
Age, Specimen part, Cell line, Treatment, Time
View SamplesOne major class of anti-cancer drugs targets topoisomerase II to induce DNA double-strand breaks and cell death of fast growing cells. In vitro experiments showed that doxorubicin can induce histone eviction as well as DNA damage, while etoposide can only induce DNA damage. Here, we compare the transcription responses of different tissues to doxorubicin or etoposide treatment in vivo.
Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin.
Age, Specimen part, Treatment, Time
View SamplesBackground and aim: The Insulin-like growth factor (IGF) axis is increasingly suggested to be involved in fatty liver disease and progression. We identified IGFBP2 as transcriptional regulatory effect network in liver steatosis and conducted a translational approach of its role in liver pathology from mouse to human, and whether it is influenced by conventional clinical intervention that mitigate hepatic steatosis. Methods: Primary hepatocytes from either C57Bl6 controls, alb-SREBP-1c mice with moderate transgene induced hepatic lipid accumulation or aP2-SREBP-1c mice with massive ectopic hepatic lipid accumulation, were analyzed to identify regulatory networks based on differentially regulated hepatic gene expression. In a translational approach, serum of morbidly obese patients with and without diabetes and biopsy-proven NAFLD were used for ELISA-based validation of mouse data. Moreover, sera of patients undergoing intervention were analyzed and correlated to liver fat content. Results: Comparative knowledge-based transcriptome analysis identified IGFBP2 as top score regulatory effect network between moderate and aggravated fatty liver in mouse models. The reduced expression of IGFBP2 in aP2-SREPB-1c progressed fatty liver associated with Igfbp2 promoter hypermethylation. Reduced secretion of IGFBP2 from aP2-SREBP-1c hepatocytes was reflected in the circulation of the animals. In this phenotype, reductions of IGFBP2 were accompanied by reduced fatty acid oxidation and increased methyltransferase and SIRT activity. Physiologically, IGFBP2 has no direct impact on lipid metabolism but might modulate IGF1 action on de novo lipogenesis. In humans, IGFBP2 levels declined from non-obese men to morbidly obese men with NAFLD and NASH. In intervention study reductions in liver fat correlated with restoration of IGFBP2 serum levels to values found in healthy individuals in morbidly obese patients following bariatric surgery. Conclusion: In hepatic metabolism changes of IGFBP2 abundance is connected to lipid metabolism whereas changes in IGFBP2 secretion were directly reflected in the circulation. IGFBP2 serum concentration correlates with the degree of fatty liver, which seems to be related to plasticity of the adipose tissue. These data provide IGFBP2 as a potential non-invasive biomarker for fatty liver disease directly reflecting the degree of impaired liver function with the potential to indicate progressed fatty liver disease.
Physiological Disturbance in Fatty Liver Energy Metabolism Converges on IGFBP2 Abundance and Regulation in Mice and Men.
Sex, Age
View SamplesDespite intense investigation of intrinsic and extrinsic factors that regulate pluripotency, the process of initial fate commitment of embryonic stem (ES) cells is still poorly understood. Here, we used a genome wide shRNA screen in mouse ES cells to identify genes that are essential for initiation of differentiation. Knockdown of the scaffolding protein Mek binding protein 1 (Mp1, also known as Lamtor3, Map2k1ip1) stimulated self-renewal of ES cells, blocked differentiation and promoted proliferation. Fibroblast growth factor 4 (FGF4) signaling is required for initial fate commitment of ES cells. Knockdown of Mp1 inhibited FGF4-induced differentiation but did not alter FGF4 driven proliferation. This uncoupling of differentiation and proliferation was also observed when oncogenic Ras isoforms were over expressed in ES cells. Knockdown of Mp1 redirected FGF4 signaling from differentiation towards pluripotency and upregulated the pluripotency-related genes Esrrb, Rex1, Tcl1 and Sox2.
A genome-wide RNAi screen in mouse embryonic stem cells identifies Mp1 as a key mediator of differentiation.
Specimen part, Cell line
View SamplesBackground In childhood acute lymphoblastic leukemia (ALL), central nervous system (CNS) involvement is rare at diagnosis (1-4%), but more frequent at relapse (~30%). Minimal residual disease diagnostics predict most bone marrow (BM) relapses, but likely cannot predict isolated CNS relapses. Consequently, CNS relapses may become relatively more important. Because of the significant late sequelae of CNS treatment, early identification of patients at risk of CNS relapse is crucial. Methods Gene expression profiles of ALL cells from cerebrospinal fluid (CSF) and ALL cells from BM were compared and differences were confirmed by real-time quantitative PCR. For a selected set of overexpressed genes, protein expression levels of ALL cells in CSF at relapse and of ALL cells in diagnostic BM samples were evaluated by 8-color flow cytometry. Results CSF-derived ALL cells showed a clearly different gene expression profile than BM-derived ALL cells, with differentially-expressed genes (including SCD and OPN) involved in survival and apoptosis pathways and linked to the JAK-STAT pathway. Flowcytometric analysis showed that a subpopulation of ALL cells (>1%) with a CNS signature (SCD positivity and increased OPN expression) was already present in BM at diagnosis in ALL patients who later developed a CNS relapse, but was <1% or absent in virtually all other patients. Conclusions The presence of a subpopulation of ALL cells with a CNS signature at diagnosis may predict isolated CNS relapse. Such information can be used to design new diagnostic and treatment strategies that aim at prevention of CNS relapse with reduced toxicity.
New cellular markers at diagnosis are associated with isolated central nervous system relapse in paediatric B-cell precursor acute lymphoblastic leukaemia.
Sex, Age, Time
View Samples