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:Non-consensus binding sites of transcription factors are often observed within the promoters and enhancers of various genes; however, their effect on transcriptional strength is unclear. Within the promoters and enhancers of NF-κB-responsive genes, we identified clusters of non- consensus κB DNA sites, many exhibiting low affinity for NF-κB in vitro. Deletion of these sites demonstrated their collective critical role in transcription. We explored how these “weak” κB sites exert their influence, especially given the typically low nuclear concentration of NF-κB. Using proteomics approaches, we identified additional nuclear factors, including other DNA-binding TFs, that could interact with κB site-bound NF-κB RelA without their direct interaction to DNA. ChIP- seq and RNA-seq analyses suggest that these accessory TFs, referred to as the TF-cofactors of NF-κB, facilitate dynamic recruitment of NF-κB to the clustered κB sites. Overall, the occupancy of NF-κB at promoters and enhancers appears to be defined by a collective contribution from all κB sites, both weak and strong, in association with specific cofactors. This congregation of multiple factors within dynamic transcriptional complexes is likely a common feature of transcriptional programs.
Project description:Post-translational modification of NF-κB subunits provides a mechanism to differentially regulate their activity in response to the many stimuli that can induce this pathway. However, the physiological significance of these modifications is largely unknown and it remains unclear if these have a critical role in the normal and pathological functions of NF-κB in vivo. Among these, phosphorylation of the RelA(p65) Thr505 residue has been described as an important regulator of NF-κB activity in cell lines but its physiological significance was not known. Therefore, to learn more about the role of this pathway in vivo, we generated a knockin mouse with a RelA T505A mutation. Unlike RelA knockout mice, the RelA T505A mice develop normally but exhibit aberrant hepatocyte proliferation following liver partial hepatectomy or damage resulting from carbon tetrachloride treatment. Consistent with these effects, RelA T505A mice exhibit earlier onset of cancer in the N-nitrosodiethylamine (DEN) model of hepatocellular carcinoma. This data reveals a critical pathway controlling NF-κB function in the liver that acts to suppress tumour-promoting activities of RelA.
Project description:Hypertensive heart failure highlights an urgent need for effective therapeutic strategies. Protein kinases regulate multiple pathways in cardiac pathophysiology and may provide promising therapeutic targets. Here, we identified a Cyclin-dependent kinase, CDK9, promoting inflammation and cardiac remodeling in terminally differentiated cardiomyocytes. Firstly, kinase enrichment analysis and experimental evidence revealed CDK9 phosphorylation at Thr-186 in both human and mouse hypertrophic heart tissues. CDK9 loss of function via T186A mutation in cardiomyocytes attenuated Ang II-induced heart remodeling and NF-κB-mediated inflammation, whereas CDK9 overactivation by T186E mutation induces. This regulatory function of CDK9 in cardiac remodeling is cell cycle-independent. Further studies demonstrate that the kinase domain of CDK9 directly binds to NF-κB P65 protein, which leads to the CDK9/P65 complex nuclear translocation, P65 phosphorylation, and transcription of inflammatory and hypertrophic genes in cardiomyocytes. This process requires CDK9 Thr-186 phosphorylation and Cyclin T1 presence, but is independent on IKKβ and CDK9-RNAPII pathways. Pharmacological inhibition of CDK9 phosphorylation significantly attenuated Ang II-induced cardiac inflammation, remodeling, and dysfunction in mice. Collectively, Ang II-activated CDK9 directly binds to and phosphorylates P65 to drive cardiac inflammation and remodeling. This study identifies CDK9 as a potential target in heart failure therapeutics
Project description:Hypertensive heart failure highlights an urgent need for effective therapeutic strategies. Protein kinases regulate multiple pathways in cardiac pathophysiology and may provide promising therapeutic targets. Here, we identified a Cyclin-dependent kinase, CDK9, promoting inflammation and cardiac remodeling in terminally differentiated cardiomyocytes. Firstly, kinase enrichment analysis and experimental evidence revealed CDK9 phosphorylation at Thr-186 in both human and mouse hypertrophic heart tissues. CDK9 loss of function via T186A mutation in cardiomyocytes attenuated Ang II-induced heart remodeling and NF-κB-mediated inflammation, whereas CDK9 overactivation by T186E mutation induces. This regulatory function of CDK9 in cardiac remodeling is cell cycle-independent. Further studies demonstrate that the kinase domain of CDK9 directly binds to NF-κB P65 protein, which leads to the CDK9/P65 complex nuclear translocation, P65 phosphorylation, and transcription of inflammatory and hypertrophic genes in cardiomyocytes. This process requires CDK9 Thr-186 phosphorylation and Cyclin T1 presence, but is independent on IKKβ and CDK9-RNAPII pathways. Pharmacological inhibition of CDK9 phosphorylation significantly attenuated Ang II-induced cardiac inflammation, remodeling, and dysfunction in mice. Collectively, Ang II-activated CDK9 directly binds to and phosphorylates P65 to drive cardiac inflammation and remodeling. This study identifies CDK9 as a potential target in heart failure therapeutics
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: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.