Project description:Complex regulatory mechanisms control continuous maintenance of myeloid progenitors and renewal of differentiated cells. Transcription factors play a important role in these processes. Here we report that the activation the calcineurin-NFAT signaling pathway inhibit the proliferation of myeloid granulocyte-monocyte progenitor (GMP). Myeloid progenitor subtypes possessed different susceptibilities to Ca2+ flux induction and consequently differential engagement of the calcineurin-NFAT pathway. This study show that inhibition of the calcineurin-NFAT pathway enhanced proliferation of GMPs both in vivo and in vitro. The calcineurin-NFAT signaling in GMPs is initiated through Flt3-L. The inhibition of the calcineurin-NFAT pathway altered the expression of the cell cycle regulation genes CDK4, CDK6, and CDKN1A, thus enabling faster cell cycle progression. The extensive use of NFAT inhibitors in the clinic should take into account that, in addition to the immunosuppression role in lymphoid cells, these NFAT inhibitors also affect the maintenance of the myeloid compartment. Microarray technology was used to understand the effects of NFAT inhibitors on C-kit enriched lineage negative cells.
Project description:Nuclear factor of activated T cells (NFAT) comprises a family of transcription factors that regulate T cell development, activation and differentiation. NFAT signaling can also mediate granulocyte and DC activation, but it is unknown whether NFAT influences their development from progenitors. Here we report a novel role for calcineurin/NFAT signaling as a negative regulator of myeloid hematopoiesis. Reconstituting lethally-irradiated mice with hematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment. Culturing bone marrow cells with Flt3-L and Cyclosporin A, which inhibits NFAT signaling, increased numbers of differentiated DC. Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis. Thus, calcineurin/NFAT signaling negatively regulates myeloid lineage development. The finding that NFAT acts as a negative regulator of myeloid development provides novel insight in understanding immune responses during treatment with calcineurin/NFAT inhibitors as Cyclosporin A. bone marrow cells from C57B/6 mice were stimulated in Flt3-L suplemented media in presence or absence of calcineurin/NFAT inhibitor Cyclosporin A, samples in 3 biological replicates
Project description:Nuclear factor of activated T cells (NFAT) comprises a family of transcription factors that regulate T cell development, activation and differentiation. NFAT signaling can also mediate granulocyte and DC activation, but it is unknown whether NFAT influences their development from progenitors. Here we report a novel role for calcineurin/NFAT signaling as a negative regulator of myeloid hematopoiesis. Reconstituting lethally-irradiated mice with hematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment. Culturing bone marrow cells with Flt3-L and Cyclosporin A, which inhibits NFAT signaling, increased numbers of differentiated DC. Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis. Thus, calcineurin/NFAT signaling negatively regulates myeloid lineage development. The finding that NFAT acts as a negative regulator of myeloid development provides novel insight in understanding immune responses during treatment with calcineurin/NFAT inhibitors as Cyclosporin A.
Project description:Genome wide expression profiling was used to detect cases of adult T-ALL lacking GATA3 expression. GATA3low T-ALL exhibited enrichment of myeloid/lymphoid progenitor (MLP) and granulocyte/monocyte progenitor (GMP) genes, while T-cell specific signatures were downregulated. Among upregulated genes FLT3 was identified and mutational analyses revealed a high rate of FLT3 mutations.
Project description:Genome wide expression profiling was used to detect cases of adult T-ALL lacking GATA3 expression. GATA3low T-ALL exhibited enrichment of myeloid/lymphoid progenitor (MLP) and granulocyte/monocyte progenitor (GMP) genes, while T-cell specific signatures were downregulated. Among upregulated genes FLT3 was identified and mutational analyses revealed a high rate of FLT3 mutations. Analysis of 83 samples of bone marrow mononuclear cells (39x HGU-133 2.0 plus chip; 44x HGU-133 A&B Set) from adult patients with acute T-cell lymphoblastic leukemia (T-ALL)
Project description:Inhibition of calcineurin-NFAT pathway at the early stage can block somatic cell reprogramming. In order to study how the calcineurin-NFAT pathway contributes to the early stage of reprogramming, we designed this microarray experiment and tried to find out which genes or signalings were changed after inhibition of calcineurin-NFAT signaling by CSA (a specific inhibitor of calcineurin-NFAT pathway).
Project description:Dendritic cells (DCs) are a special class of leukocytes able to activate both innate and adaptive immune responses. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. We have observed that following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. Indeed, LPS induces Src-family kinase and phospholipase C (PLC)γ2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. According with this observation CD14-deficient DCs do not die following LPS stimulation. Nevertheless, CD14-deficient DC death following LPS activation can be restored by co-stimulating DCs with LPS and thapsigargin. Thapsigargin empties the intracellular calcium stores by blocking calcium pumping into the sarcoplasmic and endoplasmic reticulum and thereby activates plasma membrane calcium channels. This, in turn, allows an influx of calcium into the cytosol and NFAT activation. To identify the NFAT controlled apoptosis genes in LPS activated DCs we have performed a kinetic microarray analysis (0, 48 and 60 h) in conditions allowing or inhibiting NFAT activation. Four genes have been selected: Nur77, Gadd45g, Ddit3/Gadd153/Chop-10 and Tia1. To identify apoptosis genes selectively modulated by NFAT, a comparative kinetic (time points 0, 48 and 60 h) microarray analysis was performed in the following conditions: 1) wild type bone marrow derived DCs (wtBMDCs) stimulated with LPS; 2) CD14-deficient BMDCs stimulated with LPS; 3) wtBMDCs stimulated with LPS in presence of thapsigargin; 4) CD14-deficient BMDCs stimulated with LPS in presence of thapsigargin.
Project description:Calcineurin/NFAT signaling pathway has been shown to play important roles in various tissues such as the immune system, cardiac muscle and neuron. Although recent studies have shown that the pathway is involved in the regulation of hair growth, the precise mechanism is still unclear. In this study, we examine the molecular mechanism which is regulated by calcineurin/NFAT pathway, using two specific inhibitors for the pathway. Transcriptional profiling of human keratinocyte cell line, PHK cells, comparing control untreated PHK cells with cyclosporin A (CsA)-treated or 11R-VIVIT-treated PHK cells. Goal was to identify the effects of NFAT inhibitors on PHK cell proliferation. Cyclosporine A is a chemical compound, which strongly inhibits calcineurin phosphatase activity cooperating with cyclophilin, resulting in inhibition of NFAT signaling pathway. 11R-VIVIT is a cell-permeable peptide, which specifically interacts with NFAT and inhibits its binding to calcineurin, resulting in competitive inhibition of NFAT signaling pathway. Three-condition experiment; untreated PHK cells, CsA-treated PHK cells and 11R-VIVIT-treated PHK cells. Supplementary files: Significantly up-regulated genes across 4 different comparisons.
Project description:Calcineurin/NFAT signaling pathway has been shown to play important roles in various tissues such as the immune system, cardiac muscle and neuron. Although recent studies have shown that the pathway is involved in the regulation of hair growth, the precise mechanism is still unclear. In this study, we examine the molecular mechanism which is regulated by calcineurin/NFAT pathway, using two specific inhibitors for the pathway. Transcriptional profiling of human keratinocyte cell line, PHK cells, comparing control untreated PHK cells with cyclosporin A (CsA)-treated or 11R-VIVIT-treated PHK cells. Goal was to identify the effects of NFAT inhibitors on PHK cell proliferation. Cyclosporine A is a chemical compound, which strongly inhibits calcineurin phosphatase activity cooperating with cyclophilin, resulting in inhibition of NFAT signaling pathway. 11R-VIVIT is a cell-permeable peptide, which specifically interacts with NFAT and inhibits its binding to calcineurin, resulting in competitive inhibition of NFAT signaling pathway.