Project description:In this study, we demonstrated dysregulation of DNA transcription in H3K4me3 histone in circulating neutrophils of HIV-infected subjects. Chromatin immunoprecipitation sequencing (ChIPseq) H3K4me3 histone analysis revealed that the most spectacular abnormalities were observed in the exons, introns and promoter-TSS regions. Bioinformatic analysis of Gene Ontology, including biological processes, molecular function and cellular components, demonstrated that the main changes were related to the genes responsible for cell activation, cytokine production, adhesive molecule expression, histone remodeling via upregulation of methyltransferase process and downregulation of NF-kB transcription factor in canonical pathways. Abnormalities within H3K4me3 implicated LPS-mediated NF-kB canonical activation pathway that was a result of low amounts of kB DNA sites within histone H3K4me3, low NF-kB (p65 RelA) and TLR4 mRNA expression as well as reduced free NF-kB (p65 RelA) accumulation in the nucleus. ‘Panoramic view of the landscape gene’ within histone H3K4me3 led us postulate that impairment within the canonical NF-kB cell activation pathway may be the primary phenomenon responsible for neutrophil dysfunction observed in HIV-infected individuals
Project description:Purpose: In this study we employed unbiased, genome-wide techniques to investigate how inflammation-induced NF-kB activation by acute (LPS vs. saline) and chronic (high-fat diet vs. regular chow) environmental stimuli leads to circadian disruption. Methods: We performed ChIP-seq with antibodies directed against the p65 subunit of NF-kB, CLOCK, BMAL1, H3K27Ac and RNA Poll II in livers from mice treated with LPS or saline. ChIP-seq analysis was also performed in livers from mice that were fed high-fat diet for 4 weeks or regular chow. In addition, we performed ChIP-seq with BMAL1 in mouse embryonic fibroblast deficient in p65. Results: Induction of NF-kB reconfigures the genome-wide position of core clock transcription factors. Acute (i.e. LPS) and chronic (e.g. high-fat diet) inflammation-induced NF-kB re-localizes components of the forward limb of clock (CLOCK/BMAL1) to sites convergent with NF-kB and acetylated H3K27 and enriched in RNA POL II in liver. In addition, NF-kB activation leads to higher p65 binding specific to E-box elements within the negative limb of the clock with both acute and chronic stimuli. Conclusions: Our findings cast new light on NF-kB as a pivotal genomic control node integrating metabolic inflammation and circadian systems at both the cellular and organismal levels. In particular, NF-kB directly regulates the expression of the negative limb of the clock while at the same time the clock activator TFs CLOCK/BMAL1 co-localize with NF-kB at new sites to regulate transcription following inflammatory stimuli. In addition, our data indicate significant overlap between NF-kB activation following both acute and chronic inflammatory challenges in liver.
Project description:NF-kB has been linked to doxorubicin-based chemotherapy resistance in breast cancer patients. NF-kB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined, however its functional consequences in terms the spectrum of NF-kB -dependent genes expressed and, thus, the impact on tumour cell behaviour are unclear. We hypothesized that NF-kB gene expression profile induced by doxorubicin might be different among breast cancer cells and tumors. Doxorubicin treatment in the p53-mutated MDA-MB-231 cells resulted in NF-kB driven-gene transcription demonstrated by gene expression microarrays. Selected genes (ICAM-1, CXCL1, IL8) related with invasion, metastasis and chemoresistance expression were confirmed by RT-PCR in a subset of additional doxorubicin-treated cells and fresh primary human breast tumors. In both systems, p53-deficient background correlated with the activation of these NF-kB targeted genes. Overexpression of p53WT in the mutant p53 MDA-MB-231 cells impaired NF-kB driven transcription induced by doxorubicin. Moreover, tumors with a p53 deficient background and nuclear NF-kB /p65 expression correlated with reduced disease free-survival. This study supports that tumor molecular profiles for doxorubicin driven NF-kB-response are likely to exist. A link between p53 deficiency and the presence of active transcriptionally NF-kB could favour an aggressive behaviour and might have implications for doxorubicin-based chemotherapy in breast tumors exhibiting aberrant p53 activity 12 samples were analyzed: controls (n=3); Doxorubicin treated (n=3); MLN120B treated (n=3); MLN120B + Doxorubicin treated (n=3)
Project description:We look at differential gene expression between immortalized p65+/+ and p65-/- MEFs to identify potential NF-kB regulated genes which when grouped based on biological function indicates candidates involved in protecting p65+/+ cells from macrophage-mediated killing
Project description:p65-/-Ras cells show delayed tumor formation in SCID mice. However, after prolonged latency, tumor formation was observed from these mice. To understand the changes of NF-kB regulated genes before and after tumor formation, RNA from p65+/+Ras, p65+/+RasTumor, p65-/-Ras, p65-/-RasTumor cells were isolated and microarray were performed. p65+/+Ras and p65-/-Ras cells were injected into SCID mice. Tumors were removed and put back into tissue culture. RNA was isolated from these cells and microarrays were performed.
Project description:p65-/-Ras cells show delayed tumor formation in SCID mice. However, after prolonged latency, tumor formation was observed from these mice. To understand the changes of NF-kB regulated genes before and after tumor formation, RNA from p65+/+Ras, p65+/+RasTumor, p65-/-Ras, p65-/-RasTumor cells were isolated and microarray were performed.
Project description:The inflammatory gene response requires activation of the protein kinase TAK1, but it is currently unknown how TAK1-derived signals coordinate transcriptional programs in the genome. We determined the genome-wide binding of the TAK1-controlled NF-?B subunit p65 in relation to active enhancers and promoters of transcribed genes by ChIP-seq experiments. Out of 35,000 active enhancer regions, 410 H3K4me1-positive enhancers show interleukin (IL)-1-induced H3K27ac and p65 binding. Inhibition of TAK1, IKK2 or depletion of p65 blocked inducible enhancer activation and gene expression. As exemplified by the CXC chemokine cluster located on chromosome 4, the TAK1-p65 pathway also regulates the recruitment kinetics of the histone acetyltransferase CBP, of NF-?B p50 and of AP-1 transcription factors to both, promoters and enhancers. This study provides a high resolution view of epigenetic changes occurring during the IL-1 response and allows the first genome-wide identification of a novel class of inducible p65 NF-?B-dependent enhancers in epithelial cells. RNA-seq of KB cells either untreated or treated with IL-1 alpha