ABSTRACT: APCs (A20/ DCs) were stimulated by adjuvants, CpG, MDP and MPLA respectively for 12h. Then MHC-II Immunopeptidome and proteome were perforemd
Project description:We previously reported that a synthetic Nod1 ligand, FK565, induced coronary arteritis in mice similar to Kawasaki disease. However, the molecular mechanisms underlying this site-specific inflammation have remained elusive. In this study, we found that CD11c+MHC class II+ cells accumulated in the heart of FK565-treated mice prior to arteritis development. We used microarray analysis to detail gene expression of CD11c+MHC class II+ cells. To obtain gene expression profile of CD11c+MHC class II+ cells, we isolated these cells from hearts of FK565-treated mice. Briefly, female mice at 8weeks age were administered 500 μg of FK565 subcutaneously at day 0 and day 3. At day6, murine hearts were removed and digested with collagenase. CD11c+MHC II+ cells were sorted as PI–CD45+Ly6G–NK1.1–CD11b+CD11c+MHC II+ using FACS Aria cell sorter (BD Biosciences). Sorted cells were subjected to RNA preparation. Two independent replicates from ten mice were made.
Project description:Hardy’s Fraction D bone marrow pre-B cells and splenic follicular B cells were purified by flow cytometry according to MHC II expression from wild-type and ItgaxcreH2-Ab1c MHC II conditional mice and transcriptionally profiled by RNA-seq. Duplicate or triplicate samples for each genotype and level of MHC II expression were sequenced. This is part of ongoing investigation of a possible cell-intrinsic role of MHC II B cells.
Project description:Purpose: Production of broad-spectrum antibodies against T cell-dependent antigens requires marginal zone (MZ) B cells to present antigenic peptides complexed to MHC II. Here we describe the trogocytic acquisition of these complexes from dendritic cells (DCs). Complement C3 (C3) binds to MHC II on murine and human DCs. Recognition of C3 by MZ B cell complement receptor 2 triggers trogocytosis of DC plasma membrane and its receptors, which become exposed on the MZ B cells. Excessive trogocytosis is deleterious but prevented by membrane ubiquitin ligase MARCH1, which limits the number of MHC II–C3 complexes displayed on the DC surface. MHC II molecules are thus receptors for constitutively activated and potentially harmful C3, an activity that enables acquisition of DC-like functions by trogocytic MZ B cells. Methods: mRNA profiles of splenic cDC1s, B cells and CD11cintCD24+CD8int cells of wild type (WT) and March1-/- mice mice were generated by deep sequencing, in triplicate, using Illumina HiSeq 2500. All 100-base-pair single-end reads were mapped to the reference mouse genome (GRCm38/mm10) using STAR aligner, and gene-wise counts were obtained using Subread package. Differential expression analysis of RNA sequencingdata was carried out using the edgeR and limma-voom packages in Bioconductor. Results: Using an optimized data analysis workflow, we mapped about 14 million sequence reads per sample to the mouse genome (build mm10) and identified 16,182 genes in the different cell types from WT and March1−/− mice.Transcriptomic profiling revealed over 6500 genes differentially expressed between cDC1s and B cells. Principle component analyses revealed very few differences between WT and March1−/− cDC1s, and between WT and March1−/− B cells. Notably, the transcriptome of CD11cintCD24+CD8int cells was similar to those of WT or March1−/− B cells, indicating they belonged to the B cell lineage. Conclusions: In our study we have described that MHC II ubiquitination by MARCH1 plays two important roles: first, to enhance the removal of surface MHC II–C3 complexes on all APCs; and second, to limit MZ B cell trogocytosis and elimination of cDCs. It is conceivable these two functions, more than the regulation of MHC II antigen presentation, have been the major drivers for the conservation of MHC II ubiquitination through evolution.
Project description:Our objective was to identify the potential autoantibody markers in meningiomas using high-density human proteome arrays (~17,000 full-length recombinant human proteins). This study revealed the dysregulation of 489 and 104 proteins in grades I and II of meningioma, respectively, along with the enrichment of signalling pathways which play a major role in the manifestation of the disease. This study revealed the dysregulation of 489 and 104 proteins in grades I and II of meningioma, respectively, along with the enrichment of signalling pathways which play a major role in the manifestation of the disease. Autoantibody targets like IGHG4, CRYM, EFCAB2, STAT6, HDAC7A and CCNB1 were dysregulated across both grades.
Project description:Little is known about how interactions between diet, intestinal stem cells (ISCs) and immune cells impact the early steps of intestinal tumorigenesis. Here, we show that a high fat diet (HFD) reduces the expression of the major histocompatibility complex II (MHC-II) genes in intestinal epithelial cells including ISCs. This decline in epithelial MHC-II expression in a HFD correlates with reduced diversity of the intestinal microbiome and is recapitulated in antibiotic treated and germ-free mice on a control diet. Mechanistically, pattern recognition receptor (PRR) and IFN g signaling regulate epithelial MHC-II expression where genetic ablation of these signaling pathways dampen MHC-II epithelial expression. Interestingly, upon loss of the tumor suppressor gene Apc in a HFD, MHC-II- ISCs harbor greater in vivo tumor-initiating capacity than their MHC-II+ counterparts when transplanted into immune-component hosts but not immune-deficient hosts, thus implicating a role for epithelial MHC-II-mediated immune surveillance in suppressing tumorigenesis. Finally, ISC-specific genetic ablation of MHC-II in engineered Apc-mediated intestinal tumor models increases tumor burden in a cell autonomous manner. These findings highlight how a HFD perturbs a microbiome – stem cell – immune cell crosstalk in the intestine and contributes to tumor initiation through the dampening of MHC-II expression in pre-malignant ISCs.
Project description:We previously reported that a synthetic Nod1 ligand, FK565, induced coronary arteritis in mice similar to Kawasaki disease. However, the molecular mechanisms underlying this site-specific inflammation have remained elusive. In this study, we found that CD11c+MHC class II+ cells accumulated in the heart of FK565-treated mice prior to arteritis development. We used microarray analysis to detail gene expression of CD11c+MHC class II+ cells.
Project description:F6 murine leukaemic cells were transfected either with MHC II or with GFP and transcriptionally profiled by RNA-seq. Triplicate samples for each genotype were sequenced. This is part of ongoing investigation of a possible cell-intrinsic role of MHC II B cells.
Project description:CD4+ T cells orchestrate the adaptive immune response against pathogens and cancer by recognizing epitopes presented on MHC-II molecules. The high polymorphism of MHC-II genes represents an important hurdle towards accurate predictions of CD4+ T-cell epitopes in different individuals and different species. Here we generated and curated a dataset of 627,013 unique MHC-II ligands identified by mass spectrometry. This enabled us to determine the binding motifs of 88 MHC-II alleles across human, mouse, cattle and chicken. Analysis of these binding specificities combined with X-ray crystallography refined our understanding of the molecular determinants of MHC-II motifs and revealed a widespread reverse binding mode in MHC-II ligands. We then developed a machine learning framework to accurately predict binding specificities and ligands of any MHC-II allele. This tool improves and expands predictions of CD4+ T-cell epitopes, as demonstrated by the identification of several viral and bacterial epitopes following the aforementioned reverse binding mode.