Project description:The activation signaling of transcription factor nuclear factor-kB (NF-kB) plays central role for immune system. One of key kinase mediating this pathway is TAK1 in adaptive and innate immunity. However, role of TAK1 in bone marrow B cell is still unclear. To know effects of TAK1-deletion, the gene expression of Ig-lambda/kappa positive cells were analyzed in comparison of wild type with TAK1-deficient bone marrow B cells.
Project description:B cells positive for Ig kappa and Ig lambda are observed by flow cytometry in one fourth of patients with Systemic Lupus Erythematosus (SLE). Single cell Ig VDJ sequencing (10X Genomics) reveals that kappa/lambda B cells are at the same frequency (about 1.5%) in these SLE patients as in healthy controls. Cells observed by flow cytometry are instead decorated with VH4-34 IgM (kappa or lambda) autoantibodies that are present in some but not all SLE patients.
Project description:Cells from four develppmental stages were purified by FACS from human bone marrow samples Experiment Overall Design: Cells were sorted as follows: PB1: CD34+VpreB+ PB2: VpreB-CD34+ LAR: kappa/lambda-VpreB-large SMA: kappa/lambda-VpreB-small. All cells were CD19+
Project description:We used 454 sequencing to assess the repertoire of B cell subsets from bone marrow, spleen, and small intestinal lamina propria from two mouse strains. We used a RAG2-GFP reporter mouse strain (129Sve background) to isolate CD19+ RAG2+ B lineage cells from bone marrow and small intestinal lamina propria and total splenic B cells. We used 5' RACE to amplify cDNA libraries using primers specific for the mu constant region of IgH and the Ig kappa constant region. We also used this technique to analyze total B cell libraries from Swiss Webster germ-free mice to compare to littermate controls that were cohoused with regular specific pathogen free (SPF) mice for 7 days. Examination of the Ig kappa repertoire and IgH repertoire in RAG2+ bone marrow B lineage cells compared to RAG2+ small intestinal lamina propria B lineage cells or total splenic B cells. There are 8 (Ig kappa) or 4 (IgH) independent experiments comparing repertoires in RAG2-GFP mice. Each experiment in RAG2-GFP+ mice consisted of a pool of 8-12 mice. There are 3 experiments comparing germ-free to colonized mouse total B cell repertoires, each consisting of one mouse per condition.
Project description:During B lymphopoiesis, B cell progenitors progress through alternating and mutually exclusive stages of clonal expansion and immunoglobulin (Ig) gene rearrangements. Great diversity is generated through the stochastic recombination of Ig gene segments encoding heavy and light chain variable domains. However, this commonly generates autoreactivity. Receptor editing is the predominant tolerance mechanism for self-reactive B cells in the bone marrow (BM). B cell receptor editing rescues autoreactive B cells from negative selection through renewed light chain recombination first at Igκ then Igλ loci. Receptor editing depends upon BM microenvironment cues and key transcription factors such as Nuclear factor kappa B, Forkhead box protein O and Transcription Factor 3. The specific BM factor required for receptor editing is unknown. Furthermore, how transcription factors coordinate these developmental programs to promote usage of the λ-chain remain poorly defined. Therefore, we utilized two mouse models that recapitulate pathways by which Igλ light chain positive B cells develop. The first possess deleted J kappa (Jκ) genes and, as such, models Igκ expression resulting from failed Igκ recombination (Igκdel). The second models autoreactivity by ubiquitous expression of a single-chain chimeric anti-Igκ antibody (κ-mac). Here, we demonstrated that autoreactive B cells transit asymmetric forward and reverse developmental trajectories. This imparted a unique epigenetic landscape on small pre-B cells, which opened chromatin to transcription factors essential for Igλ recombination. The consequences of this asymmetric developmental path were both amplified and complemented by CXCR4 signaling. These findings reveal how intrinsic molecular programs integrate with extrinsic signals to drive receptor editing.
Project description:ATAC-seq profiling of Nfat5 KO and wild type macrophages derived from bone marrow (primary cells), treated or not with Lipopolysaccharide (LPS).
Project description:We used 454 sequencing to assess the repertoire of B cell subsets from bone marrow, spleen, and small intestinal lamina propria from two mouse strains. We used a RAG2-GFP reporter mouse strain (129Sve background) to isolate CD19+ RAG2+ B lineage cells from bone marrow and small intestinal lamina propria and total splenic B cells. We used 5' RACE to amplify cDNA libraries using primers specific for the mu constant region of IgH and the Ig kappa constant region. We also used this technique to analyze total B cell libraries from Swiss Webster germ-free mice to compare to littermate controls that were cohoused with regular specific pathogen free (SPF) mice for 7 days.