Project description:As we clarified before, the FOXP3 gene is an X-linked tumor suppressor gene in mammary carcinoma in both human and mouse. We also clarified that the ERBB2 and SKP2 oncogenes were transcriptionally under control of the FOXP3 gene product in mammary epithelial cells. In order to further clarify the FOXP3 down stream target genes in human breast cancer cells, we planed to conduct a microarray analysis of FOXP3-induced gene expression profiling. MCF7, a human breast cancer cell line, with FOXP3-tet-off system was cultured with and without Doxycyclin for 2 days. In the MCF7 cell cultured without Dox, the FOXP3 transcript was significantly induced as compared to the MCF7 cultured with Dox. Total RNA from MCF7 with and wihtout Dox were extracted by Qiagen's RNeasy column and they were applied to Affymetrix Human U133 2.0 array according to the manufacture's protocol. We clarified as yet unknown FOXP3 target genes in human epithelial cells, e.g., the p21 gene, by this analysis.
Project description:As we clarified before, FOXP3 gene is an X-linked tumor suppressor for both human and mouse. And we also clarified direct target genes of FOXP3 in human cancer cells. Recently we identified that MOF, a histone acetyltransferase, can be a FOXP3's molecular partner to regulate target gene expression. We conducted a microarray analysis using MCF7 cell, a human breast cancer cell line, with FOXP3-tet-off system with and without MOF knock down before and after FOXP3 overexpression. After 48 hrs of RNAi treatments in MCF7 cells, FOXP3 was overexpressed and those cells were cultured for additional 48 hrs. Total RNA were extracted using Qiagen's RNeasy column and were applied to Affymetrix Human U133 Plus 2.0 array according to the manufacture's protocol.
Project description:The downstream events and target genes of p53 in senescence responses are not fully understood. Here, we report a novel function of the forkhead transcription factor Foxp3, a key player in mediating T cell inhibitory function, in p53-mediated cellular senescence. Overexpression of Foxp3 in mouse embryonic fibroblasts (MEFs) accelerates senescence, whereas Foxp3 knockdown leads to escape from p53-mediated senescence in p53-expressing MEFs. Consistently, Foxp3 expression resulted in the induction of senescence in epithelial cancer cells, including MCF7 and HCT116. Foxp3 overexpression also increased the intracellular levels of reactive oxygen species (ROS). The ROS inhibitor N-acetyl-L-cysteine rescued Foxp3 expression-induced senescence. Furthermore, the elevated ROS levels that accompanied Foxp3 overexpression were paralleled by an increase in p21 expression. Knockdown of p21 in Foxp3-expressing MEFs abrogated the Foxp3-dependent increase in ROS levels, indicating that Foxp3 acts through p21 induction and subsequent ROS elevation to trigger senescence. Collectively, these results suggest that Foxp3 is a downstream target of p53 that is sufficient to induce p21 expression and ROS production and is necessary for p53-mediated senescence. control and treated samples (human), young passage (p3) or old passage (p7) samples (mouse)
Project description:As we clarified before, the FOXP3 gene is an X-linked tumor suppressor gene of both human and mouse. We also clarified that the ERBB2, SKP2 and p21 genes were transcriptionally under control of FOXP3 in human epithelial cells. In order to further clarify the FOXP3 down stream targets in human cancer cells, we conducted a microarray analysis of FOXP3-induced gene expression profiling. A human prostate cancer cell line, LNCaP, was transfected either with a FOXP3-eGFP expressing vector or an eGFP-expressing vector. After 48 hrs of cell culture, we isolated eGFP-positive LNCaP cells by FACS sorting, and then total RNA from those cells were extracted by Qiagen's RNeasy column and they were applied to Affymetrix Human U133 2.0 array according to the manufacture's protocol. We clarified as yet unknown FOXP3 target genes in human prostate epithelial cells by this analysis.
Project description:The transcription factor (TF) Forkhead Box P3 (FOXP3) is constitutively expressed in high levels in natural occurring CD4+CD25+ regulatory T cells (nTreg) and is not only the most accepted marker for that cell population, but is considered lineage determinative. Chromatin immunoprecipitation (ChIP) of transcription factors in combination with genomic tiling microarray analysis (ChIP-on-Chip) has been shown to be an appropriate tool to identify FOXP3 transcription factor binding sites (TFBS) on a genome-wide scale. In combination with microarray expression analysis the ChIP-on-Chip technique allows to identify direct FOXP3 target genes. ChIP-on-Chip analysis of human FOXP3M-NM-^T2 isoform expressed in resting and PMA / ionomycin stimulated Jurkat T cells revealed several thousand putative FOXP3 binding sites and importance of intronic regions for FOXP3 binding. Knowledge of general distribution patterns of FOXP3 TFBS in the human genome under resting and activated conditions contributes to a better understanding of this TF and its influence on direct target genes with importance for Treg cell phenotype and function. ChIP-DNA from FOXP3(M-NM-^T2) expressing Jurkat T cells under resting and PMA / ionomycin stimulated conditions from duplicate experiments was analyzed. FOXP3-specific tiling array data were analyzed in reference to an individual isotype control dataset (J-FOXP3 ChIP'd with FOXP3 antibody vs. J-FOXP3 ChIP'd with isotype control antibody). In total 8 tiling array analyses were performed (2x resting J-FOXP3 with FOXP3-IP, 2x resting J-FOXP3 with isotype-IP, 2x PMA/iono J-FOXP3 with FOXP3-IP, 2x PMA/iono J-FOXP3 with isotype-IP)
Project description:The downstream events and target genes of p53 in the process of senescence are not fully understood. Here, we report a novel function of the forkhead transcription factor Foxp3, which is a key player in mediating T cell inhibitory functions, in p53-mediated cellular senescence. The overexpression of Foxp3 in mouse embryonic fibroblasts (MEFs) accelerates senescence, whereas Foxp3 knockdown leads to escape from p53-mediated senescence in p53-expressing MEFs. Consistent with these results, Foxp3 expression resulted in the induction of senescence in epithelial cancer cells, including MCF7 and HCT116 cells. Foxp3 overexpression also increased the intracellular levels of reactive oxygen species (ROS). The ROS inhibitor N-acetyl-L-cysteine rescued cells from Foxp3-expression-induced senescence. Furthermore, the elevated ROS levels that accompanied Foxp3 overexpression were paralleled by an increase in p21 expression. Knockdown of p21 in Foxp3-expressing MEFs abrogated the Foxp3-dependent increase in ROS levels, indicating that Foxp3 acts through the induction of p21 and the subsequent ROS elevation to trigger senescence. Collectively, these results suggest that Foxp3 is a downstream target of p53 that is sufficient to induce p21 expression and ROS production and is necessary for p53-mediated senescence.
Project description:Regulatory T cells have been shown to adopt a catabolic metabolic programme with increased capacity for fatty acid oxidation fuelled oxidative phosphorylation (OXPHOS). The role of Foxp3 in this metabolic shift is poorly understood. Here we show that Foxp3 was sufficient to induce a significant increase in the spare respiratory capacity of the cell, the extra OXPHOS capacity available to a cell to increased demands on energy in response to work. Foxp3-expressing cells were enhanced in their ability to utilise palmitate for respiration and in addition the activity of electron transport complexes I, II and IV were enhanced following Foxp3 expression. ATP was secreted by both T effector and regulatory T cells and was reduced by mitochondrial respiration inhibitors. Thus Foxp3 imparts a selective advantage in ATP generation capacity to the cell and may exploit this as a source of adenosine for functional immunomodulation. In order to explore possible mechanisms for these differences in metabolism we conducted a comparative quantitative proteomics study to compare the contribution of TGFβ and the transcription factor Foxp3 to the Treg proteome. We used quantitative mass spectrometry to examine differences between proteomes of nuclear and cytoplasmic Foxp3-containing T cells and Foxp3 positive iTreg and Foxp3 negative activated CD4 T cells in addition to human peripheral blood natural Treg. Gene set enrichment analysis of our proteomic datasets demonstrated that Foxp3 drives a significant up regulation of several members of the mitochondrial electron transport chain.
Project description:Regulatory T cells (Treg) have been shown to adopt a catabolic metabolic programme with increased capacity for fatty acid oxidation fuelled oxidative phosphorylation (OXPHOS). The role of Foxp3 in this metabolic shift is poorly understood. Here we show that Foxp3 was sufficient to induce a significant increase in the spare respiratory capacity of the cell, the extra OXPHOS capacity available to a cell to meet increased demands on energy in response to work. Foxp3-expressing cells were enhanced in their ability to utilise palmitate for respiration and, in addition, the activity of electron transport complexes I, II and IV were enhanced following Foxp3 expression. Foxp3 also imparts a selective advantage in ATP generation capacity, one that might be exploited as a source of adenosine for functional immunomodulation. In order to explore possible mechanisms for these differences in metabolism we conducted a quantitative proteomics study to compare the contribution of TGFβ and the transcription factor Foxp3 to the Treg proteome. We used quantitative mass spectrometry to examine differences between proteomes of nuclear and cytoplasmic Foxp3-containing CD4+ T cells from various sources with Foxp3- activated CD4 T cells, as well as Treg from human peripheral blood. Gene set enrichment analysis of our proteomic datasets demonstrated that Foxp3 expression is associated with a significant up regulation of several members of the mitochondrial electron transport chain. Not only does Foxp3 influence genes directly concerned with immune function, but also with the energy generating functions of Treg.
Project description:Analysis of Foxp3(+)epigenetics(-) T cells, Foxp3(-)epigenetics(+) T cells, and Foxp3(+)epigenetics(+) T cells. Results indicate regulatory T cell (Treg) ontogenesis requires two independent processes, expression of the transcription factor Foxp3 and establishment of Treg epigenetic programs induced by T cell receptor (TCR) stimulation. GFP+CD4+ and GFP-CD4+ splenocytes were sorted from DEREG and DEREG/Scurfy mice. These cells were activated with anti-CD3/CD28 antibodies, and then transduced with Foxp3-expressing retrovirus (pGCSamIN, NGFR marker). NGFR+ T cells sorted were subjected to microarray analysis (Affymetrix, mouse genome 430 2.0 array). To normalize the experimental conditions, Tregs (GFP+ T cells from DEREG) and Tconv (GFP- T cells from DEREG) were also activated and transduced with empty vector. Two replicates each.