Project description:To try to identify the mechanism of STAT3âs indirect action we have used a genomic approach to map the binding sites of STAT3 within the genome and also used RNA-seq technology to map the changes in RNA expression and transcript isoforms in response to IL-10. Examination of STAT3 binding by ChIP-seq in Unstimulated and IL-10 treated peritoneal exudate macrophages purified from mice. We sequenced anti-STAT3 ChIP-seq as well as corresponding control (Input) libraries
Project description:Interleukin-21 (IL-21) is a pleiotropic cytokine that induces expression of transcription factor BLIMP1 (encoded by Prdm1), which regulates plasma cell differentiation and T cell homeostasis. We identified an IL-21 response element downstream of Prdm1 that binds the transcription factors STAT3 and IRF4, which are required for optimal Prdm1 expression. Genome-wide ChIP-Seq mapping of STAT3- and IRF4-binding sites showed that most regions with IL-21-induced STAT3 binding also bound IRF4 in vivo, and furthermore, revealed that the noncanonical TTCnnnTAA GAS motif critical in Prdm1 was broadly used for STAT3 binding. Comparing genome-wide expression array data to binding sites revealed that most IL-21-regulated genes were associated with combined STAT3-IRF4 sites rather than pure STAT3 sites. Correspondingly, ChIP-Seq analysis of Irf4_/_ T cells showed greatly diminished STAT3 binding after IL-21 treatment, and Irf4_/_ mice showed impaired IL- 21-induced Tfh cell differentiation in vivo. These results reveal broad cooperative gene regulation by STAT3 and IRF4. Affymetrix expression data: Prepare CD4+ T cells from spleen. CD4+ T cells were preactivated, rested, and treated with IL-21 for 1, 6, and 24 hours. ChIP-seq data: Profiling of IRF4 and Stat3 binding with and without IL-21 stimulation in wild type and IRF4 KO mice.
Project description:STAT3, an essential transcription factor with pleiotropic functions, plays critical roles in the pathogenesis of autoimmunity. Despite recent data linking STAT3 with inflammatory bowel disease, exactly how it contributes to chronic intestinal inflammation is not known. Using a T cell transfer model of colitis we found that STAT3 expression in T cells was essential for the induction of both colitis and systemic inflammation. STAT3 was critical in modulating the balance of T helper 17 (Th17) and regulatory T (Treg) cells, as well as in promoting CD4+ T cell proliferation. We used chromatin immunoprecipitation and massive parallel sequencing (ChIP-Seq) to define the genome-wide targets of STAT3 in CD4+ T cells. We found that STAT3 bound to multiple genes involved in Th17 cell differentiation, cell activation, proliferation and survival, regulating both expression and epigenetic modifications. Thus, STAT3 orchestrates multiple critical aspects of T cell function in inflammation and homeostasis. This SuperSeries is composed of the following subset Series: GSE21669: Diverse Targets of the Transcription Factor STAT3 Contribute to T Cell Pathogenicity and Homeostasis [ChIP-seq] GSE21670: Diverse Targets of the Transcription Factor STAT3 Contribute to T Cell Pathogenicity and Homeostasis [Affymetrix Expression] Refer to individual Series
Project description:Activation of JAK-STAT3 signaling by leukemia inhibitory factor (LIF) is required for maintaining self-renewal of mouse embryonic stem cells (mESCs). STAT3 perform cell type-specific roles in different cell type, here we revisit the role of STAT3 using mouse female germ stem cell (mFGSCs). We applied CRISPR/Cas9 system to generate Stat3 knockout FGSCs and then observed cell growth inhibition and cell cycle arrest in KO cell line. By combining genome wide ChIP-Seq and RNA-Seq, we identified 5990 STAT3 binding sites and discovered serval genes specific regulated by STAT3 that were involved in stem cell proliferation and female gonad development in FGSCs. In general, we identify key roles of STAT3 for sustains self-renewal and proliferation for FGSCs in this study.
Project description:Inflammatory breast cancer (IBC) is a difficult-to-treat disease with poor clinical outcomes due to high risk of metastasis and resistance to treatment. We previously described a CD44+CD24-pSTAT3+ cancer cell subpopulation with stem cell-like features in breast cancer that is dependent on JAK/STAT3 signaling. Here we report that CD44+CD24- cells are the most frequent cell-type in IBC and are commonly pSTAT3+. Combination of JAK/STAT3 inhibition with paclitaxel decreased IBC xenograft growth more than either agent alone. We developed and characterized IBC cell lines resistant to paclitaxel and doxorubicin to mimic therapeutic resistance in patients. Multi-omic profiling of parental and resistant cells revealed genes associated with lineage identity and inflammation were enriched in chemotherapy resistant derivatives. Integrated pSTAT3 ChIP-seq and RNA-seq analyses showed pSTAT3 regulates genes related to inflammation and epithelial to mesenchymal transition (EMT) in resistant cells, as well as PDE4A, a cAMP-specific phosphodiesterase. Metabolomic characterization identified elevated cAMP signaling and CREB as a candidate therapeutic target in IBC. We also investigated cellular dynamics and heterogeneity at the single cell level during chemotherapy and acquired resistance by CyTOF and single cell RNA-seq. We identified mechanisms of resistance including a shift from luminal to basal/mesenchymal cell states through selection for rare pre-existing subpopulations or an acquired change. Lastly, we showed that combination treatment with paclitaxel and JAK/STAT3 inhibition prevented the emergence of this more mesenchymal chemo-resistant subpopulation. Our results provide mechanistic rational for combination of chemotherapy with inhibition of JAK/STAT3 signaling as a new more effective therapeutic strategy in IBC.
Project description:The basic understanding of the biological effects of eukaryotic translation initiation factors (EIFs) remains incomplete. Here, we analyzed the function of EIF3F, which is commonly found to be overexpressed in human lung adenocarcinoma, and discovered that EIF3F promotes cell migration and metastasis in vivo. The underpinning molecular mechanisms involved the upregulation of a cluster of 34 metastasis-promoting genes including Snail2 (SLUG), as revealed by proteomics combined with immuno-affinity purification of EIF3F and ChIP-seq/Q-PCR analyses. The interaction between EIF3F and Signal Transducer and Activator of Transcription 3 (STAT3) controlled the EIF3F-mediated increase in Snail2 expression and cellular invasion, which were specifically abrogated using the STAT3 inhibitor nifuroxazide. Our findings demonstrate the role of EIF3F in the molecular control of cell migration, invasion and metastasis.
Project description:Diffuse large B cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma, includes two main molecular subtypes: activated B cell-like (ABC) DLBCL and germinal center B cell-like (GCB) DLBCL. ABC DLBCL is more aggressive, with the activated JAK1-STAT3 pathway that promotes cell survival. In order to study the underlying pathogenic mechanism, we performed a ChIP-seq experiment by phospho-STAT3(Tyr705) antibody in ABC DLBCL cell lines, and identified 3,456 STAT3 target genes genome-wide. In parallel, ChIP-seq experiment was performed with STAT3 antibody in α-IgM stimulated naïve B cells for verification of these targets of STAT3 protein. TMD8 was treated by eithor DMSO or AZD1480 (JAK inhibitor) for 4hrs, ChIP-seq experiments were performed by pSTAT3(Tyr705) antibody (#9145S, Cell signaling). Naïve B cells were collected from peripheral blood mononuclear cells by Naive B Cell Isolation kit (miltenyi biotec; 130-091-150), and treated by 10ug/ml α-IgM (southernbiotech; #2020-01) for 24hrs. ChIP-seq experiments were performed by STAT3 antibody (SC-482X, Santa Cruz).
Project description:Dendritic cells (DC) play a vital role in the induction of activation or tolerance of immune response. STAT3 is a master transcriptional regulator of immune response in DCs by positively or negatively regulating DC function, but the mechanisms are unknown. STAT3 is post-translationally modified by acetylation or phosphorylation. While much is understood about transcriptional targets of phosphorylated STAT3, the gene targets and the functional impact of acetylated-STAT3 remain unclear. We aimed to answer the gene targets of acetylated-STAT3 and test the hypothesis that acetylation of STAT3 plays a key role in negative regulation of DCs. We performed genome-wide binding analysis of acetyl-STAT3 by ChIP-Seq coupled with gene expression microarrays. Acetylation of STAT3 induced by SAHA increased its capability to bind to target DNA sites in genome. Theses binding sites were mostly proximal but some were also distal up to over 100 kb from transcription start site. Gene expression array showed 1701 genes up-regulated and 1668 genes down-regulated. Proximal binding of acety-STAT3 showed more effective transcription function than distal binding. In top 500 binding peaks, the frequency of canonical motifs bound by acetyl-STAT3 were significantly higher than that for noncanonical motifs (p<0.00001). Functional analysis revealed that acetyl-STAT3 regulates target genes by upregulating genes that are primarily involved in negative regulation of cytokine production and IL-10 signaling, or downregulating genes that are primarily involved in immune effector process and antigen processing/presentation. Upregulation of IL-10Ra by acetyl-STAT3 contributes to the enhanced sensitivity of IL-10 signaling and negative regulation of DC function. Bone marrow derived dendritic cells were treated with SAHA (500 nm) or diluent for 12 hours. ChIP was performed using antibodies against STAT3, H3K4me3 and matched IgG control. DNA binding profiles were generated by deep sequencing using Illumina HiSeq 2000.
Project description:Interleukin 2 (IL-2), a cytokine linked to human autoimmune diseases, limits IL-17 production. We show that deletion of Stat3 in T cells abrogates IL-17 production and attenuates autoimmunity associated with IL-2 deficiency. While STAT3 induces IL-17 and RORγt and inhibits Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and RORγt. We found that STAT3 and STAT5 bound to multiple common sites across the Il17 genetic locus. The induction of STAT5 binding by IL-2 was associated with a reduction in STAT3 binding at these sites and the inhibition of associated active epigenetic marks. Titrating the relative activation of STAT3 and STAT5 modulated TH17 cell specification. Thus, the balance rather than the absolute magnitude of these signals determines the propensity of cells to make a key inflammatory cytokine. The genome-wide binding of STAT3 and STAT5 under Th17 conditions was investigated by CHIP-seq.
Project description:Transcription factor recruitment to genomic sites of action is primarily due to direct protein:DNA interactions. The subsequent recruitment of co-regulatory complexes leads to either transcriptional activation or repression. In contrast to this canonical scheme, some transcription factors such as the glucocorticoid receptor (GR) behave as transcriptional repressors when recruited to target genes through protein tethering. We have investigated the genome-wide prevalence of tethering between GR and Stat3 and found non-reciprocal interactions, namely that GR tethering to DNA-bound Stat3 results in transcriptional repression whereas Stat3 tethering to GR results in synergism. Further, other schemes of GR and Stat3 co-recruitment to regulatory modules result in transcriptional synergism, including neighbouring and composite binding sites. The results indicate extensive transcriptional interactions between Stat3 and GR; further, they provide a genome-wide assessment of transcriptional regulation by tethering and a molecular basis for integration of signals mediated by GR and Stats in health and disease. ChIP-seq analysis of Stat3 and GR binding sites in pituitary corticotroph AtT-20 cell model. Five independant ChIPs were pooled prior library preparation for each contitions: STAT3 (LIF), STAT3 (Dex+LIF), GR (Dex+LIF), GR (Dex) and control IgG.