Project description:PURPOSE: The goal of this study was to determine the gene expression networks regulated by tumor necrosis factor receptor 2 (TNFR2, or Tnfrsf1b) and to evaluate their potential bearing on immune cell subsets and inflammatory bowel disease (IBD). METHODS: mRNA-seq was performed on isolated distal colons from TNFR2-knockout and wildtype mice. Differentially expressed transcripts were compared to human ulcerative colitis microarray datasets on Gene Expression Omnibus and to mouse immunological expression datasets at the Immunological Genome Project. RESULTS: We identified 252 mouse transcripts whose expressions were significantly altered by the loss of TNFR2. The majority of these transcripts (228 of 252, ~90%) were downregulated in TNFR2-/- colons. TNFR2-regulated genes were able to positively discriminate between ulcerative colitis patients and healthy individuals with ~80% accuracy. Many TNFR2-regulated genes were also highly expressed in CD8+ T cells. CONCLUSIONS: Downregulation of TNFR2 is associated with a gene expression profile that is prominent in IBD and supportive of the role of CD8+ T cells in IBD pathogenesis. MANUSCRIPT ABSTRACT: Increased tumor necrosis factor (TNF) production has been associated with inflammatory bowel disease (IBD), and anti-TNF therapy is a common therapeutic for this patient population. However, the role of TNF or its receptors (TNFR1 and TNFR2) in the immunopathogenesis of inflammatory bowel disease (IBD) remains unclear. Here we report that TNFR2 is protective in spontaneous (IL-10 knockout) and chemically (azoxymethane/dextran sodium sulfate)-induced mouse models of colitis and colitis-associated cancer. Mechanistically, TNFR2-deficiency in hematopoietic cells significantly increased incidence and severity of colitis and colitis-associated cancer characterized by a selective expansion of CD8+ T cells. We identified TNFR2-regulated genes in the colon that were specific for CD8+ T cells, interacted with multiple IBD risk genes, and are important regulators of CD8+ T cell biology. TNFR2 regulated CD8+ T-cell-specific genes that act as genetic susceptibility modifiers for IBD to mitigate the development of a pro-colitogenic milieu. Antibody-mediated depletion of CD8+ T cells prevented colonic inflammation and significantly reduced pathology in IL10-/-/TNFR2-/- deficient mice. Furthermore, adoptive transfer of TNFR2-/- naïve CD8+ T cells resulted in more severe disease than with wildtype naïve CD8+ T cells. Our findings provide insight into the disease modifier role of TNFR2 in the immunopathogenesis of IBD through the modulation of CD8+ T cell responses and support future investigation of this therapeutic target, especially in the subset of IBD patients with CD8+ T-cell dysfunction. Total RNA from distal colons of 8 week-old male wildtype C57Bl/6 and TNFR2-/- mice (n=3 each) was isolated using the PureLink RNA kit (Ambion, Life Technologies). RNA samples were submitted to the Genomic Services Lab at the HudsonAlpha Institute for Biotechnology (Huntsville, AL) for multiplex library preparation, mRNA enrichment, and sequencing. Sequencing was performed to an average depth of 50M paired-end 50bp reads per sample (HiSeq, Illumina, San Diego, CA). Data files containing raw reads were aligned to the mouse genome using Tophat2/Bowtie2. Alignments were assembled into transcript representations with Cufflinks, and statistical tests for differential expression were performed with Cuffdiff 2. An adjusted P value < 0.05 (q<0.05) from the Cuffdiff 2 output was used as the cutoff for statistical significance.

Project description:PURPOSE: The goal of this study was to determine the gene expression networks regulated by tumor necrosis factor receptor 2 (TNFR2, or Tnfrsf1b) and to evaluate their potential bearing on immune cell subsets and inflammatory bowel disease (IBD). METHODS: mRNA-seq was performed on isolated distal colons from TNFR2-knockout and wildtype mice. Differentially expressed transcripts were compared to human ulcerative colitis microarray datasets on Gene Expression Omnibus and to mouse immunological expression datasets at the Immunological Genome Project. RESULTS: We identified 252 mouse transcripts whose expressions were significantly altered by the loss of TNFR2. The majority of these transcripts (228 of 252, ~90%) were downregulated in TNFR2-/- colons. TNFR2-regulated genes were able to positively discriminate between ulcerative colitis patients and healthy individuals with ~80% accuracy. Many TNFR2-regulated genes were also highly expressed in CD8+ T cells. CONCLUSIONS: Downregulation of TNFR2 is associated with a gene expression profile that is prominent in IBD and supportive of the role of CD8+ T cells in IBD pathogenesis. MANUSCRIPT ABSTRACT: Increased tumor necrosis factor (TNF) production has been associated with inflammatory bowel disease (IBD), and anti-TNF therapy is a common therapeutic for this patient population. However, the role of TNF or its receptors (TNFR1 and TNFR2) in the immunopathogenesis of inflammatory bowel disease (IBD) remains unclear. Here we report that TNFR2 is protective in spontaneous (IL-10 knockout) and chemically (azoxymethane/dextran sodium sulfate)-induced mouse models of colitis and colitis-associated cancer. Mechanistically, TNFR2-deficiency in hematopoietic cells significantly increased incidence and severity of colitis and colitis-associated cancer characterized by a selective expansion of CD8+ T cells. We identified TNFR2-regulated genes in the colon that were specific for CD8+ T cells, interacted with multiple IBD risk genes, and are important regulators of CD8+ T cell biology. TNFR2 regulated CD8+ T-cell-specific genes that act as genetic susceptibility modifiers for IBD to mitigate the development of a pro-colitogenic milieu. Antibody-mediated depletion of CD8+ T cells prevented colonic inflammation and significantly reduced pathology in IL10-/-/TNFR2-/- deficient mice. Furthermore, adoptive transfer of TNFR2-/- naïve CD8+ T cells resulted in more severe disease than with wildtype naïve CD8+ T cells. Our findings provide insight into the disease modifier role of TNFR2 in the immunopathogenesis of IBD through the modulation of CD8+ T cell responses and support future investigation of this therapeutic target, especially in the subset of IBD patients with CD8+ T-cell dysfunction.

Project description:While considerable progress has been made towards understanding the complex processes and pathways that regulate human wound healing, regenerative medicine has been unable to develop therapies that coax the natural wound environment to heal scar-free. The inability to induce perfect skin regeneration stems partly from our limited understanding of how scar-free healing occurs in a natural setting. Here we have investigated the wound repair process in adult axolotls and demonstrate that they are capable of perfectly repairing full thickness excisional wounds made on the flank. In the context of mammalian wound repair, our findings reveal a substantial reduction in hemostasis, reduced neutrophil infiltration and a relatively long delay in production of new extracellular matrix (ECM) during scar-free healing. Additionally, we test the hypothesis that metamorphosis leads to scarring and instead show that terrestrial axolotls also heal scar-free, albeit at a slower rate. Analysis of newly forming dermal ECM suggests that low levels of fibronectin and high levels of tenascin-C promote regeneration in lieu of scarring. Lastly, a genetic analysis during wound healing comparing epidermis between aquatic and terrestrial axolotls suggests that matrix metalloproteinases may regulate the fibrotic response. Our findings outline a blueprint to understand the cellular and molecular mechanisms coordinating scar-free healing that will be useful towards elucidating new regenerative therapies targeting fibrosis and wound repair. We used microarray analysis to determine the gene expression changes that take place during scar free wound healing in aquatic and terrestrial axolotl salamanders. Epidermal tissue was harvested using a 4mm biopsy punch. Two wounds were made along the flank and posterior to the forelimbs. Harvested epidermis was pooled for each animal. Four biological replicates were collected from uninjured epidermis (D0) and at 1, 3, and 7 days post injury.

Project description:Wound healing is an essential homeostatic mechanism that maintains the epithelial barrier integrity after tissue damage. Although we know the main events participating in the healing of a wound, many of the underlying molecular mechanisms remain unclear. Genetically amenable systems, such as wound healing in Drosophila imaginal discs, do not model all aspects of the repair process, but allow exploring many unanswered features of the healing response; e.g., which are the signal(s) responsible for initiating tissue remodeling? How is the sealing of the epithelia achieved? Or which are the inhibitory cues that cancel the healing machinery upon completion? Answering these and other questions demands in first place the identification and functional analysis of wound-specific genes. A variety of different microarray analyses of murine and humans have identified characteristic profiles of gene expression at the wound site, however, very few functional studies in healing regulation have been carried out. We developed an experimentally controlled method to culture imaginal discs that allows live imaging and biochemical analysis and is healing-permissive. Employing this approach, we performed a comparative genome-wide profiling between those Drosophila imaginal cells actively involved in healing versus their non-engaged siblings. This lets us identify a set of potential wound-specific genes. Importantly, besides identifying and categorizing new genes, we functionally tested many of their gene products by genetic interference and overexpression in a healing assay. This non-saturated analysis defines a relevant set of new genes whose changes in expression levels are functionally significant for proper tissue repair. There is promise that our newly identified wound-healing genes will guide future work in the more complex mammalian wound response. We developed a healing-permissive in vitro culture system for fly imaginal discs: we used one-channel microarrays for comparing healing-engaged cells (showing activation of the JNK signaling cascade) to cells not participating in healing (silent JNK activity) in wounded wing imaginal discs in culture. Employing this method, we aimed detecting the relevant genes involved in disc healing through microarray analysis. We compared cells actively involved in healing to those not involved and identified a whole set of upregulated or downregulated genes. They were annotated, clustered by expression profiles, chromosomal locations and presumptive functions. Most importantly, we functionally tested them genetically in a healing assay.

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Single-cell analysis of colonic organoids deficient for tumor necrosis factor receptor 2

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