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: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:Retinoic acid (RA) triggers physiological processes by activating heterodimeric transcription factors comprising retinoic acid (RARa,b,g) and retinoid X (RXRa,b,g) receptors. How a single signal induces highly complex temporally controlled networks that ultimately orchestrate physiological processes is unclear. Using an RA-inducible differentiation model we defined the temporal changes in the genome-wide binding patterns of RARg and RXRa and correlated them with transcription regulation. Unexpectedly, both receptors displayed a highly dynamic binding, with different RXRa heterodimers targeting identical loci. Comparison of RARg and RXRa co-binding at RA-regulated genes identified putative RXRa-RARg target genes that were validated with subtype-selective agonists. Gene regulatory decisions during differentiation were inferred from transcription factor target gene information and temporal gene expression. This analysis revealed 6 distinct co-expression paths of which RXRa-RARg is associated with transcription activation, while Sox2 and Egr1 were predicted to regulate repression. Finally, RXRa-RARg regulatory networks were reconstructed through integration of functional co-citations. Our analysis provides a dynamic view of RA signalling during cell differentiation, reveals RA heterodimer dynamics and promiscuity, and predicts decisions that diversify the RA signal into distinct gene-regulatory programs. Transcriptional activity in F9 cells treated with different retinoic acid receptor (RAR) agonists; like all-trans retinoic acid (ATRA), BMS961 (RARg-specific), BMS753 (RARa-specific) or BMS641(RARb-specific); has been evaluated at different time-points (2, 6, 24, 48h) and compared with that found under Ethanol-vehicle treatment conditions (48h treatment).
Project description:Retinoic acid (RA), the main active vitamin A metabolite, controls multiple biological processes such as cell proliferation and differentiation through genomic programs and kinase cascades activation. Due to these properties, RA has proven anti-cancer capacity. Several breast cancer cells respond to the antiproliferative effects of RA, while others are RA-resistant. However, the overall signaling and transcriptional pathways that are altered in such cells have not been elucidated. Here, in a large-scale analysis of the phosphoproteins and in a genome-wide analysis of the RA-regulated genes, we compared two human breast cancer cell lines, a RA-responsive one, the MCF7 cell line, and a RA-resistant one, the BT474 cell line, which depicts several alterations of the "kinome".
Project description:Retinoic acid (RA), the main active vitamin A metabolite, controls multiple biological processes such as cell proliferation and differentiation through genomic programs and kinase cascades activation. Due to these properties, RA has proven anti-cancer capacity. Several breast cancer cells respond to the antiproliferative effects of RA, while others are RA-resistant. However, the overall signaling and transcriptional pathways that are altered in such cells have not been elucidated. Here, in a large-scale analysis of the phosphoproteins and in a genome-wide analysis of the RA-regulated genes, we compared two human breast cancer cell lines, a RA-responsive one, the MCF7 cell line, and a RA-resistant one, the BT474 cell line, which depicts several alterations of the "kinome".
Project description:This Series reports results of miRNA profiling of estrogen-receptor-positive (MCF7) and estrogen-receptor-negative (MDA-MB-231) cells. Retinoic Acid (RA) induces mir-21 in MCF-7 but not in MDA-MB-231 cells. MCF-7 and MDA-MB-231 cells were treated (or not) with retinoic acid (RA) and grown for either 6 hours or 48 hours. miRNA profiling: Factorial design 2x2x2 'cube'; main factors: RA, cells, time; interactions: RA.cells, RA.time, cells.time, RA.cells.time.
Project description:This Series reports results of miRNA profiling of estrogen-receptor-positive (MCF7) and estrogen-receptor-negative (MDA-MB-231) cells. Retinoic Acid (RA) induces mir-21 in MCF-7 but not in MDA-MB-231 cells. MCF-7 and MDA-MB-231 cells were treated (or not) with retinoic acid (RA) and grown for either 6 hours or 48 hours.
Project description:The aim of this study was to investigate the response of FLS from RA patients to retinoic acid and retinoic acid combined with the central cytokine of RA, TNF.
Project description:The hypothesis was tested that the Pbx1-d isoform was responsible for the Sle1a.1 phenotypes in CD4+ T cells. Jurkat T cells were transfected with a lentiviral construct expressing Pbx1-d-GFP or control RFP. Pbx1-d over-expression reduced the percentage of late apoptotic cells in response to anti-CD3 and anti-CD28 stimulation as compared with control-Lin28-transfected cells. Overall, these data demonstrate that over-expression of Pbx1-d results in an activated/inflammatory phenotype and in a defective response to RA in Jurkat T cells, strongly suggesting that the increased expression of Pbx1-d is responsible for the Sle1a.1 phenotypes.