Project description:OCA-B, OCA-T1, and OCA-T2 belong to a family of transcriptional coactivators that bind to POU transcription factors (TFs) to regulate gene expression in immune cells. Here, we identify IkBz (encoded by the NFKBIZ gene) as the fourth member of the OCA protein family. While originally discovered as an inducible regulator of NFkB, we show here that IkBz shares a microhomology with OCA proteins and uses this segment to simultaneously bind to POU transcription factors and octamer motif-containing DNA. Our functional reporter assays suggest that IkBz requires its interaction with POU TFs to coactivate immune-related genes. This finding is reinforced by our epigenomic analysis of MYD88 L265P-mutant lymphoma cells, which revealed colocalization of IkBz, the POU transcription factor OCT2, and NFkB:p50 at hundreds of DNA elements harboring octamer and kB motifs. These results suggest that IkBz is a transcriptional coactivator that integrates and amplifies the output of NFkB and POU transcription factors at inducible genes in immune cells.
Project description:NF-κB has an essential role in innate immune response and inflammation and is involved in cancer development and progression. We apply the SEC-PCP-SILAC method incorporating metabolic labeling, size exclusion chromatography and protein correlation profiling to construct a complex network of interactome rearrangement in response to NF-κB modulation in breast cancer cells. Our interaction network represents a complex insight into the dynamics of MCF-7 protein interactome associated with NF-κB pathway. Our dataset could serve as a basis for future studies characterizing role of NF-κB in breast cancer cellular pathways. This PRIDE project includes results from SILAC labeled and label-free replicates from the SEC-PCP-SILAC analysis of protein complexes in MCF-7 cells with inhibited and uninhibited NF-κB pathway, results from the immunoprecipitation experiment aimed at interaction partners of NF-κB factor RELA, analysis of total proteome after NF-κB inhibition, and results from SEC fractionation of untreated and unlabeled MCF-7 cells.
Project description:The transcription factor NF-κB is the master regulator of the immune response but also regulates gene expression to influences cell survival, proliferation and differentiation. Inducible site-specific phosphorylation of NF-κB is critical for its activity and appears to be important in gene specific transcriptional control. Promyelocytic Leukemia (PML) is a nuclear protein that forms sub-nuclear structures termed nuclear bodies associated with transcriptionally active genomic regions. We demonstrate that PML promotes NF-κB- induced transcriptional responses by promoting the phosphorylation of NF-κB p65 at key regulatory sites. Our findings demonstrate a critical role for PML in promoting NF-κB transcriptional activity through signal induced post-translational modifications.
Project description:Transcriptional profiling of human control and Néstor-Guillermo Progeria Syndrome (NGPS) fibroblasts and induced pluripotent stem cells (iPSCs). Somatic cell reprogramming involves rejuvenation of adult cells and relies on the ability to erase age-associated molecular marks. Accordingly, reprogramming efficiency declines with ageing, and age-associated features such as genetic instability, cell senescence or telomere shortening negatively affect this process. However, the regulatory mechanisms that constitute age-associated barriers for cell reprogramming remain largely unknown. Here, by using cells from patients with premature ageing, we demonstrate that NF-κB activation is a critical barrier for the generation of induced pluripotent stem cells (iPSCs) in ageing. We show that NF-κB repression occurs during cell reprogramming towards a pluripotent state. Conversely, ageing-associated NF-κB hyperactivation impairs generation of iPSCs by eliciting reprogramming repressors DOT1L and YY1, reinforcing cell senescence signals and down-regulating pluripotency genes. We also show that genetic and pharmacological NF-κB inhibitory strategies significantly increase the reprogramming efficiency of fibroblasts from Néstor-Guillermo Progeria Syndrome (NGPS) and Hutchinson-Gilford Progeria Syndrome (HGPS) patients, as well as from normal aged donors. Finally, we demonstrate that DOT1L inhibition in vivo ameliorates the accelerated ageing phenotype and extends lifespan in a progeroid animal model. Collectively, our results provide evidence for a novel role of NF-κB in the control of cell fate transitions and reinforce the interest of studying age-associated molecular impairments to implement cell reprogramming methodologies, and to identify new targets of rejuvenation strategies. Control and NGPS fibroblasts were reprogrammed. RNA was extracted and transcriptional profiling was obtained with GeneChip Human Exon 1.0 ST Arrays.
Project description:Transcriptional profiling of human control and Néstor-Guillermo Progeria Syndrome (NGPS) mesenchymal stem cells (MSCs). Somatic cell reprogramming involves rejuvenation of adult cells and relies on the ability to erase age-associated molecular marks. Accordingly, reprogramming efficiency declines with ageing, and age-associated features such as genetic instability, cell senescence or telomere shortening negatively affect this process. However, the regulatory mechanisms that constitute age-associated barriers for cell reprogramming remain largely unknown. Here, by using cells from patients with premature ageing, we demonstrate that NF-κB activation is a critical barrier for the generation of induced pluripotent stem cells (iPSCs) in ageing. We show that NF-κB repression occurs during cell reprogramming towards a pluripotent state. Conversely, ageing-associated NF-κB hyperactivation impairs generation of iPSCs by eliciting reprogramming repressors DOT1L and YY1, reinforcing cell senescence signals and down-regulating pluripotency genes. We also show that genetic and pharmacological NF-κB inhibitory strategies significantly increase the reprogramming efficiency of fibroblasts from Néstor-Guillermo Progeria Syndrome (NGPS) and Hutchinson-Gilford Progeria Syndrome (HGPS) patients, as well as from normal aged donors. Finally, we demonstrate that DOT1L inhibition in vivo ameliorates the accelerated ageing phenotype and extends lifespan in a progeroid animal model. Collectively, our results provide evidence for a novel role of NF-κB in the control of cell fate transitions and reinforce the interest of studying age-associated molecular impairments to implement cell reprogramming methodologies, and to identify new targets of rejuvenation strategies. Control and NGPS MSCs were differentiated into bone in the presence or absence of sodium salicylate. Total RNA was extracted and global gene expression was analyzed.
Project description:Monocyte chemoattractant protein 1 (MCP-1/CCL2) is critically involved in directing the migration of blood monocytes to sites of inflammation. Consequently, excessive MCP-1 secretion has been linked to many (auto)inflammatory diseases, whereas a lack of expression severely impairs immune responsiveness. We demonstrate that the atypical inhibitor of NF-κB ζ (IκBζ), a transcriptional co-activator required for the selective expression of a subset of NF-κB target genes, is a key activator of the Ccl2 gene. IκBζ-deficient macrophages exhibited impaired secretion of MCP-1 when challenged with diverse inflammatory stimuli, such as lipopolysaccharide or peptidoglycan. These findings were reflected at the level of Ccl2 gene expression, which was tightly coupled to the presence of IκBζ. Moreover, mechanistic insights acquired by chromatin immunoprecipitation demonstrate that IκBζ is directly recruited to the proximal promoter region of the Ccl2 gene and required for histone H3K9 trimethylation. Finally, IκBζ-deficient mice showed significantly impaired MCP-1 secretion and monocyte infiltration in an experimental model of peritonitis. Together, these findings suggest a distinguished role of IκBζ in mediating the targeted recruitment of monocytes in response to local inflammatory events. Peritoneal macrophages from Wildtype and IκBζ-Knockout mice were either stimulated with 1µg/ml LPS for 4h or left untreated (triplicates each)
Project description:MTD project_description Inflammation and decreased stem cell function characterize organism aging, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signals, by increasing chromatin accessibility of inter-/intra-genic and enhancer regions. Rad21/NF-κB are required for normal differentiation, but limit self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB dependent manner. HSCs from aged mice fail to downregulate Rad21/cohesin and inflammation/differentiation inducing signals in the resolution phase after acute inflammation. and The inhibition of cohesin/NF-κB is sufficient to revert the hypersensitivity of aged HSPCs to inflammation-induced differentiation. During aging, myeloid-biased HSCs with disrupted and naturally occurring reduced expression of Rad21/cohesin are increasingly selected over lymphoid-biased HSCs. Together, Rad21/cohesin mediated NF-κB signaling limits HSPC function during aging and selects for cohesin deficient HSCs with myeloid skewed differentiation.
Project description:Over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). In this study, by manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, we identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes, such as immune system process, response to stress, response to stimulus, defense response and signaling pathways of NF-kappa B. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. The NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR.
Project description:Over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). In this study, by manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, we identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes, such as immune system process, response to stress, response to stimulus, defense response and signaling pathways of NF-kappa B. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. The NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR.
Project description:NF-κB is a key regulator of innate and adaptive immunity and is implicated in the pathogenesis of acute kidney injury (AKI). The cell type-specific functions of NF-κB in the kidney are unknown; however, the pathway serves distinct functions in immune and tissue-parenchymal cells. We analyzed tubular epithelial-specific NF-κB signaling in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. NF-κB reporter activity and nuclear localization of phosphorylated NF-κB subunit p65 analyses in mice revealed widespread NF-κB activation in renal tubular epithelia and in interstitial cells following IRI that peaked at 2-3 days after injury. To genetically antagonize tubular epithelial NF-κB activity, we generated mice expressing the human NF-κB super-repressor IκBα∆N in renal proximal, distal, and collecting duct epithelial cells. These mice were protected from IRI-induced AKI, as indicated by improved renal function, reduced tubular apoptosis, and attenuated neutrophil and macrophage infiltration. Tubular NF-κB-dependent gene expression profiles revealed temporally distinct functional gene clusters for apoptosis, chemotaxis, and morphogenesis. Primary proximal tubular cells isolated from IκBα∆N-expressing mice exposed to hypoxia-mimetic agent cobalt chloride were protected from apoptosis and expressed reduced levels of chemokines. Our results indicate that postischemic NF-κB activation in renal-tubular epithelia aggravates tubular injury and exacerbates a maladaptive inflammatory response.