ABSTRACT: Cell cyclin kinase inhibitor Cdkn2c regulates B cell homeostasis and function in the NZM2410-derived murine lupus susceptibility locus Sle2c1
Project description:Sle2c1 is an NZM2410-derived lupus susceptibility locus that induces an expansion of the B1a cell compartment. B1a cells have a repertoire enriched for autoreactivity, and an expansion of this B cell subset occurs in several mouse models of lupus. Here we showed that expression of Sle2c1 enhances NZB cellular phenotypes that have been associated with autoimmune pathogenesis. A combination of genetic mapping and candidate gene analysis presents Cdkn2c, a gene encoding for cyclin kinase inhibitor p18INK4c (p18), as the top candidate gene for inducing the Slec2c1 associated expansion of B1a cells. A novel SNP in the Cdkn2c promoter is associated with a significantly reduced Cdkn2c expression in the splenic B cells and B1a cells from Sle2c1-carrying mice, which leads to defective G1 cell cycle arrest in splenic B cells and increased proliferation of Pc B1a cells. As cell cycle is differentially regulated in B1a and B2 cells, these results suggest that Cdkn2c play a critical role in B1a cell self renewal, and that its impaired expression leads to an accumulation of these cells with high autoreactive potential. Total RNA from peritoneal cavity B cells (B1a) and splenic B cells (Bs) was isolated, with 4 biological replicates each. Gene expression data from C57BL/6 mice were compared with data from B6.Sle2c1 mice.
Project description:Sle2c1 is an NZM2410-derived lupus susceptibility locus that induces an expansion of the B1a cell compartment. B1a cells have a repertoire enriched for autoreactivity, and an expansion of this B cell subset occurs in several mouse models of lupus. Here we showed that expression of Sle2c1 enhances NZB cellular phenotypes that have been associated with autoimmune pathogenesis. A combination of genetic mapping and candidate gene analysis presents Cdkn2c, a gene encoding for cyclin kinase inhibitor p18INK4c (p18), as the top candidate gene for inducing the Slec2c1 associated expansion of B1a cells. A novel SNP in the Cdkn2c promoter is associated with a significantly reduced Cdkn2c expression in the splenic B cells and B1a cells from Sle2c1-carrying mice, which leads to defective G1 cell cycle arrest in splenic B cells and increased proliferation of Pc B1a cells. As cell cycle is differentially regulated in B1a and B2 cells, these results suggest that Cdkn2c play a critical role in B1a cell self renewal, and that its impaired expression leads to an accumulation of these cells with high autoreactive potential.
Project description:Common genetic variants in a 58-kilobase (kb) region of chromosome 9p21, near the CDKN2A/B cell proliferation inhibitor genes, are strongly associated with coronary artery disease (CAD). We previously reported a congenic mouse model harboring an atherosclerosis susceptibility locus in a region of homology with the human 9p21 locus. We now report markedly decreased Cdkn2a (cyclin-dependent kinase inhibitor 2a) mRNA expression in macrophages and increased circulating levels of Ly6Chigh inflammatory monocytes in congenic mice compared to controls. A bone marrow (BM) transplantation study revealed that BM-derived cells from Cdkn2a+/- mice are capable of conferring accelerated atherosclerosis, increased inflammatory monocyte subsets and monocyte proliferation in the Ldlr-/- mouse model. These findings provide a mechanistic link between decreased expression of Cdkn2a transcripts, increased monocyte proliferation, and accelerated atherosclerosis. Aorta and macrophages from ten C57BL/6.MOLFc4(51Mb)-Ldlr-/- mice and their control C57BL/6-Ldlr-/- were obtained, RNA purified and hybridized to GPL9734 Affimetrix microarrays.
Project description:Common genetic variants in a 58-kilobase (kb) region of chromosome 9p21, near the CDKN2A/B cell proliferation inhibitor genes, are strongly associated with coronary artery disease (CAD). We previously reported a congenic mouse model harboring an atherosclerosis susceptibility locus in a region of homology with the human 9p21 locus. We now report markedly decreased Cdkn2a (cyclin-dependent kinase inhibitor 2a) mRNA expression in macrophages and increased circulating levels of Ly6Chigh inflammatory monocytes in congenic mice compared to controls. A bone marrow (BM) transplantation study revealed that BM-derived cells from Cdkn2a+/- mice are capable of conferring accelerated atherosclerosis, increased inflammatory monocyte subsets and monocyte proliferation in the Ldlr-/- mouse model. These findings provide a mechanistic link between decreased expression of Cdkn2a transcripts, increased monocyte proliferation, and accelerated atherosclerosis.
Project description:FAAH expresson is induced in Sle2 splenic B cells. Increased peripheral B cell receptor revision, or selective peripheral expansion of BCR-revised B-cells, may lead to systemic autoimmunity, and FAAH is a lupus susceptibility gene that could regulate this process in Sle2 mice. To determine the gene expression profile in peripheral B cells from Sle2 mice (compared to B6 mice), we isolated splenic B cells from these two strains of mice, extracted the total mRNA and performed the microarray analysis Please note that Sle2 mouse is a congenic strain that harbors the Sle2 locus from Chromosome 4 of NZM2410 strain in a B6 background and Sle2 is the name of the lupus susceptibility locus.
Project description:Sle1c is a sublocus of the NZM2410-derived Sle1 major susceptibility locus. We have previously shown that Sle1c contributes to lupus pathogenesis by conferring CD4+ T cell-intrinsic hyperactivation and increased susceptibility to chronic graft-versus-host disease (cGVHD) that mapped to the centromeric portion of the locus. In this study, we have refined the centromeric sublocus to a 675Kb interval, termed Sle1c2. Recombinant congenic strains expressing Sle1c2 exhibited a T cell-intrinsic CD4+ T cell hyperactivation and cGVHD susceptibility, similar to mice with the parental Sle1c. We performed a microarray analysis on CD4+ T cells to gain insights into the transcriptional programs that regulate the hyperactivation conferred by Sle1c2. CD4+ T cell cDNA was prepared from spenocytes from 5 mice from each strain and B6.Sle1c2 gene expression was compared to B6 gene expresion.
Project description:Sle1c is a sublocus of the NZM2410-derived Sle1 major susceptibility locus. We have previously shown that Sle1c contributes to lupus pathogenesis by conferring CD4+ T cell-intrinsic hyperactivation and increased susceptibility to chronic graft-versus-host disease (cGVHD) that mapped to the centromeric portion of the locus. In this study, we have refined the centromeric sublocus to a 675Kb interval, termed Sle1c2. Recombinant congenic strains expressing Sle1c2 exhibited a T cell-intrinsic CD4+ T cell hyperactivation and cGVHD susceptibility, similar to mice with the parental Sle1c. We performed a microarray analysis on CD4+ T cells to gain insights into the transcriptional programs that regulate the hyperactivation conferred by Sle1c2.
Project description:Sle1a.1 is part of the Sle1a lupus susceptibility locus which results in the production of activated and autoreactive CD4+ T cells as well as a reduction in the peripheral regulatory T cell (Treg) pool. Sle1a.1 CD4+ T cells showed a defective response to retinoic acid (RA) expansion of TGFβ-induced Tregs. At the molecular level, Sle1a.1 corresponds to an increased expression of a novel splice isoform of Pbx1, Pbx1-d. Pbx1-d over-expression is sufficient to induce an activated/inflammatory phenotype in Jurkat T cells, and to decrease their apoptotic response to RA. PBX1-d is expressed more frequently in lupus patients than in healthy controls, and its presence correlates with an increased memory T cell population. These findings indicate that Pbx1 is a novel lupus susceptibility gene that regulates T cell activation and tolerance. Total RNA from CD4+ T cells from C57BL/6 (B6) and B6.Sle1a.1 (Sle) mice was isolated, with 4 biological replicates each. Gene expression data from C57BL/6 mice were compared with data from B6.Sle2c1 mice.
Project description:Sle1a.1 is part of the Sle1a lupus susceptibility locus which results in the production of activated and autoreactive CD4+ T cells as well as a reduction in the peripheral regulatory T cell (Treg) pool. Sle1a.1 CD4+ T cells showed a defective response to retinoic acid (RA) expansion of TGFβ-induced Tregs. At the molecular level, Sle1a.1 corresponds to an increased expression of a novel splice isoform of Pbx1, Pbx1-d. Pbx1-d over-expression is sufficient to induce an activated/inflammatory phenotype in Jurkat T cells, and to decrease their apoptotic response to RA. PBX1-d is expressed more frequently in lupus patients than in healthy controls, and its presence correlates with an increased memory T cell population. These findings indicate that Pbx1 is a novel lupus susceptibility gene that regulates T cell activation and tolerance.
Project description:ABSTRACT Background: The expression of BCL11B has been reported in normal and transformed cells derived from T-lymphocytes, neurons, keratinocytes and recently in a subset of squamous cell carcinomas. Despite the rapidly accumulating knowledge concerning Bcl11b biology, the contribution of this protein to normal or transformed cell homeostasis remains open. Methodology/Principal Findings: Here, by employing an overexpression strategy and cells endogenously expressing BCL11B we revealed formerly unidentified features of Bcl11b which shed some light on the potential involvement of the protein in tumor maintenance. Two different T cell lines were forced to overexpress BCL11B which resulted in markedly increased resistance to radiomimetic drugs while no influence on death-receptor apoptotic pathway was observed. Apoptosis resistance triggered by BCL11B overexpression was accompanied by a cell cycle delay caused by accumulation of cells at G1. This cell cycle restriction was associated with upregulation of CDKN1C (p57) and CDKN2C (p18) cyclin dependent kinase inhibitors. Moreover, p27 and p130 proteins accumulated and the SKP2 gene encoding a protein of the ubiquitin-binding complex responsible for their degradation was repressed. Furthermore, the expression of the MYCN oncogene was silenced which resulted in significant depletion of the protein in cells expressing high BCL11B levels. Both cell cycle restriction and resistance to DNA-damage-induced apoptosis coincided and required the histone deacetylase binding N-terminal domain of Bcl11b. The sensitivity to genotoxic stress could be restored by the histone deacetylase inhibitor trichostatine A. Conclusions: The data presented here suggest a potential role of BCL11B in tumor survival and encourage developing Bcl11b-inhibitory approaches as a potential tool to specifically target chemoresistant tumor cells. Using a retroviral-vector-based system in Jurkat cells BCL11B overexpression was compared to controls transfected with the empty vector. Of each group one biological replicate was analyzed on one array.