Project description:We report here that ABCs exhibited a unique phenotype in aging and lupus model mice, where BCR signaling is constitutively activated, and surface BCRs are internalized. Autoreactive anergic B cells exclusively differentiated into ABCs in a BCR-dependent manner in vivo. Additionally, anergic B cells showed enhanced ABC differentiation in vitro compared to naive B cells. This was suppressed by Nr4a1 expression, possibly due to the inhibition of several signaling pathways, including BCR.
Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated A 12 chip study using cDNA from three separate 2525 LMP2A knockout LCL cultures and three separate 3696.10 LMP2A:mCD69 LCL cultures; each culture tested before and after 90 min stimulation of the BCR and LMP2A:mCD69, respectively.
Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated
Project description:compare gene expression profiles between normal and anergic T cells and identify upregulated genes in anergic T cells Experiment Overall Design: RNA from normal Th1 T cell clone and anergic Th1 T cell clone made anergic by plate-bound anti-CD3 antibody were isolated and amplified for microarray analysis
Project description:Although Bcr-Abl kinase inhibitors have proven effective in the treatment of chronic myeloid leukemia (CML), they generally fail to completely eradicate Bcr-Abl+ leukemia cells. To identify genes whose inhibition sensitizes Bcr-Abl+ leukemias to killing by Bcr-Abl inhibitors, we performed an RNAi-based synthetic lethal screen with imatinib in CML cells. This screen identified numerous components of a Wnt/Ca2+/NFAT signaling pathway. Antagonism of this pathway led to impaired NFAT activity, decreased cytokine production and enhanced sensitivity to Bcr-Abl inhibition. Furthermore, NFAT inhibition with cyclosporin A facilitated leukemia cell elimination by the Bcr-Abl inhibitor dasatinib and markedly improved survival in a mouse model of Bcr-Abl+ acute lymphoblastic leukemia (ALL). Targeting this pathway in combination with Bcr-Abl inhibition could improve treatment of Bcr-Abl+ leukemias. We utilized a genome-wide shRNA library in combination with microarray analysis to screen for gene targets in chronic myeloid leukemia cells that cooperate with imatinib.
Project description:Rattus norvegicus Bcr, BCR activator of RhoGEF and GTPase [Source:RGD Symbol;Acc:1307993], is differentially expressed in 26 experiment(s);
Project description:Rattus norvegicus Bcr, BCR activator of RhoGEF and GTPase [Source:RGD Symbol;Acc:1307993], is expressed in 6 baseline experiment(s);
Project description:Xenopus tropicalis bcr, BCR, RhoGEF and GTPase activating protein [Source:Xenbase;Acc:XB-GENE-980812], is differentially expressed in 1 experiment(s);
Project description:Macaca mulatta BCR, BCR activator of RhoGEF and GTPase [Source:VGNC Symbol;Acc:VGNC:97739], is expressed in 3 baseline experiment(s);