Project description:Siglec-1 is a macrophage lectin-like receptor that mediates sialic acid-dependent cellular interactions. It was shown previously to promote inflammation in autoimmune disease through suppressing the expansion of regulatory T cells (Tregs). We have investigated the molecular basis for Siglec-1 binding to these cells using in vitro-induced Tregs. A proximity labelling and proteomics strategy were used to identify glycoproteins expressed by activated Tregs that may function as Siglec-1 counter-receptors.
Project description:The aim of the project is to do proteomic analysis of total cell lysate from rest and activated mouse Tregs. The proteomic data were mapped to the Gene Ontology Cellular Component (GOCC)database to obtain the list of membrane proteins on activated Tregs. The set of membrane proteins identified were compared with the potential Siglec-1 counter-receptors on activated Tregs.
Project description:In previous studies, we identified the fungal macrocyclic lactone (S)-curvularin (SC) as an anti-inflammatory agent using a screening system detecting inhibitors of the Janus kinase/signal transducer and activator of transcription pathway. The objective of the present study was to investigate whether SC is able to decrease proinflammatory gene expression in an in vivo model of a chronic inflammatory disease. Therefore, the effects of SC and dexamethasone were compared in the model of collagen-induced arthritis (CIA) in mice. In addition to measuring the arthritis index (paw swelling) of the animals, we also performed whole genome microarray analyses to identify SC target genes and new therapeutic targets of SC.
Project description:Siglec-1 is a macrophage lectin-like receptor that mediates sialic acid-dependent cellular interactions. It was shown previously to promote inflammation in autoimmune disease through suppressing the expansion of regulatory T cells (Tregs). We have investigated the molecular basis for Siglec-1 binding to these cells using in vitro-induced Tregs. A proximity labelling and proteomics strategy were used to identify glycoproteins expressed by activated Tregs that may function as Siglec-1 counter-receptors.
Project description:Metastasis is responsible for the majority of deaths in a variety of cancer types, including breast cancer. Although several factors or biomarkers have been identified to predict the outcome of patients with breast cancer, few studies have been conducted to identify metastasis-associated biomarkers. Quantitative iTRAQ proteomics analysis was used to detect differentially expressed proteins between lymph node metastases and their paired primary tumor tissues from 23 patients with metastatic breast cancer. Immunohistochemistry was performed to validate the expression of two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins in 190 paraffin-embedded tissue samples. These four proteins were further analyzed for their correlation with clinicopathological features in 190 breast cancer patients. We identified 637 differentially regulated proteins (397 upregulated and 240 downregulated) in lymph node metastases compared with their paired primary tumor tissues. Furthermore, bioinformatics analysis using GEO profiling confirmed the difference in the expression of EpCAM between metastases and primary tumors tissues. Two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins were associated with the progression of breast cancer. Obviously, EpCAM plays a role in the metastasis of breast cancer cells to the lymph node. We further identified αB-crystallin as an independent biomarker to predict lymph node metastasis and the outcome of breast cancer patients.
Project description:The trasncription factor cMyc is an essential transcription factor that establishes a metabolically active and proliferative state in T cells after antigen priming. However, its expression is transient. To date, it remains unknown how T cell activation is maintained after cMyc down-regulation. Here, we identify AP4, encoded by the gene Tfap4, as the transcription factor that is induced by cMyc and sustains activation of antigen-specific CD8+ T cells. Despite normal priming, Tfap4–/– CD8+ T cells fail to continue transcription of a broad range of cMyc gene targets necessary for sustained proliferation. Genome-wide analysis suggests that many activation-induced metabolic genes are shared targets of cMyc and AP4. Thus, AP4 maintains Myc-initiated cellular activation programs in CD8+ T cells to control microbial infections. Naive CD8+ T cells from C57BL6 mice were activated with anti-CD3 and anti-CD28 stimulation in vitro for two days and genome-wide occupancy of Myc, AP4 and Ser2 or Ser5 phipsphorylated RNA polymerase II was profiled by chromatin immunoprecipitation and high-throughput sequencing.
Project description:Alternative polyadenylation is an important cellular mechanism that enables generation of mRNA isoforms that differ in their 3' untranslated regions (3' UTRs) and consequently in their susceptibility to miRNA and RNA binding protein mediated regulation. A dramatic change in polyadenylation site usage, leading to the systematic expression of short 3’ UTR isoforms is known to occur upon induction of proliferation in resting cells. To understand the functional consequences of short 3’ UTR isoform expression we used 3' end sequencing and quantitative mass spectroscopy to determine polyadenylation site use, mRNA and protein levels in murine and human naive and activated T cells. We found that while the process and its impact on the susceptibility to miRNA and RNA binding protein mediated regulation are evolutionarily conserved, the conservation is poor at the level of individual orthologous genes. Contrary to the common belief, we did not find that transcriptome-wide 3' UTR shortening leads to a matched increase in mRNA and protein levels of genes with tandem polyadenylation sites. 3' ends of transcripts were profiled by high-throughput sequencing in murine and human naive and activated T cells.
Project description:Naïve T cells respond to antigen stimulation by exiting from quiescence into clonal expansion and functional differentiation, but the control mechanism is elusive. Here we describe that Raptor/mTORC1-dependent metabolic reprogramming is a central determinant of this transitional process. Loss of Raptor abrogates T cell priming and Th2 cell differentiation, although Raptor function is less important for continuous proliferation of actively cycling cells. mTORC1 coordinates multiple metabolic programs in T cells including glycolysis, lipid synthesis and oxidative phosphorylation to mediate antigen-triggered exit from quiescence. mTORC1 further links glucose metabolism to the initiation of Th2 differentiation by orchestrating cytokine receptor expression and cytokine responsiveness. Activation of Raptor/mTORC1 integrates T cell receptor (TCR) and CD28 co-stimulatory signals in antigen-stimulated T cells. Our studies identify a Raptor/mTORC1-dependent pathway linking signal-dependent metabolic reprogramming to quiescence exit, and this in turn coordinates lymphocyte activation and fate decisions in adaptive immunity. We used microarrays to explore the gene expression profiles differentially expressed in CD4+ T-cells from wild-type (WT) and CD4(cre) x Raptor(fl/fl) mice before and after stimulation with anti CD3/CD28 antibodies.