The platelet-derived growth factor receptor alpha (PDGFR) exhibits divergent effects in skeletal muscle. At physiological levels, signaling through this receptor promotes muscle development in growing embryos and proper angiogenesis in regenerating adult muscle. However, either increased PDGF ligands or enhanced PDGFR pathway activity causes pathological fibrosis. This excessive collagen deposition, which is seen in aged and diseased muscle, interferes with proper muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders. Although compelling evidence exists for the role of PDGFR in fibrosis, little is known about the cells through which this pathway acts. Here we show that PDGFR signaling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated. We found that FAPs produce multiple transcriptional variants of PDGFR with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signaling and to prevent FAP over-activation. Moreover, increasing expression of this isoform limits fibrosis in vivo, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem cell populations.
Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis.
Sex, Specimen part, Treatment
View SamplesThe platelet-derived growth factor receptor alpha (PDGFR) exhibits divergent effects in skeletal muscle. At physiological levels, signaling through this receptor promotes muscle development in growing embryos and proper angiogenesis in regenerating adult muscle. However, either increased PDGF ligands or enhanced PDGFR pathway activity causes pathological fibrosis. This excessive collagen deposition, which is seen in aged and diseased muscle, interferes with proper muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders. Although compelling evidence exists for the role of PDGFR in fibrosis, little is known about the cells through which this pathway acts. Here we show that PDGFR signaling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated. We found that FAPs produce multiple transcriptional variants of PDGFR with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signaling and to prevent FAP over-activation. Moreover, increasing expression of this isoform limits fibrosis in vivo, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem cell populations.
Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis.
Sex, Specimen part, Treatment
View SamplesExpression profiles of anti-TNF responders were compared to profiles of anti-TNF non-responders in order to identify an expression signature for anti-TNF response
Validation study of existing gene expression signatures for anti-TNF treatment in patients with rheumatoid arthritis.
Specimen part, Disease, Disease stage, Treatment
View SamplesExpression analysis of migrating and non-migrating mesenchymal stromal cells (MSC) in fetal bone marrow
Nuclear receptors Nur77 and Nurr1 modulate mesenchymal stromal cell migration.
Specimen part
View SamplesRecent 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 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 SamplesStudy on gene expression in multifunctional protein 2 deficient mice. Liver samples of two days old mice in normal conditions are used. In total 8 arrays were hybridized corresponding to 4 KO mice and 4 WT mice Results: Cholesterol synthesis is induced and ppar alpha targets also differentially expressed between KO and WT.
Coordinate induction of PPAR alpha and SREBP2 in multifunctional protein 2 deficient mice.
No sample metadata fields
View SamplesIn GnRH-antagonist/rec-FSH stimulated cycles, advanced endometrial maturation on the day of oocyte retrieval correlates with altered gene expression
In GnRH antagonist/rec-FSH stimulated cycles, advanced endometrial maturation on the day of oocyte retrieval correlates with altered gene expression.
No sample metadata fields
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