Project description:Hepatitis C virus (HCV) infection leads to the development of hepatic diseases, as well as extrahepatic disorders such as B-cell non-Hodgkin's lymphoma (B-NHL). To reveal the molecular signalling pathways responsible for HCV-associated B-NHL development, we utilised transgenic (Tg) mice that express the full-length HCV genome specifically in B cells and develop non-Hodgkin type B-cell lymphomas (BCLs). The gene expression profiles in B cells from BCL-developing HCV-Tg mice, from BCL-non-developing HCV-Tg mice, and from BCL-non-developing HCV-negative mice were analysed by genome-wide microarray. In BCLs from HCV-Tg mice, the expression of various genes was modified, and for some genes, expression was influenced by the gender of the animals. Markedly modified genes such as Fos, C3, LTβR, A20, NF-κB and miR-26b in BCLs were further characterised using specific assays. We propose that activation of both canonical and alternative NF-κB signalling pathways and down-regulation of miR-26b contribute to the development of HCV-associated B-NHL.
Project description:Most liver tumors arise on the basis of chronic liver diseases that trigger inflammatory responses. Besides inflammation, subsequent defects in the p53-signaling pathway frequently occurs in liver cancer. In this study, we analyzed the consequences of inflammation and p53 loss in liver carcinogenesis. We used inducible liver-specific transgenic mouse strains to analyze the consequences of NF-κB/p65 activation mimicking chronic inflammation and subsequent p53 loss. Ikk2ca driven NF-κB/p65 activation in mice results in liver fibrosis, the formation of ectopic lymphoid structures and carcinogenesis independent of p53 expression. Subsequent deletion of Trp53 led to an increased tumor formation, metastasis and a shift in tumor differentiation towards intrahepatic cholangiocarcinoma. In addition, loss of Trp53 in an inflammatory liver resulted in elevated chromosomal instability and indicated a distinct aberration pattern. In conclusion, activation of NF-κB/p65 mimicking chronic inflammation provokes the formation of liver carcinoma. Collateral disruption of Trp53 supports tumor progression and influences tumor differentiation and heterogeneity.
Project description:Nuclear factor kappa B (NF-κB) is a key regulator in immune signaling and is known to exhibit a digital activation pattern. Yet the molecular basis underlying the heterogeneity in NF-κB activation at single-cell level is not entirely understood. Here, we show that NF-κB activation in single cells is largely regulated by intrinsic differences at the receptor level. Using the genome editing and time-lapse imaging, we directly characterize endogenous TNFR1 dynamics and NF-κB activation from the same single cells. Total internal reflection fluorescence (TIRF) microscopy shows that endogenous TNFR1 forms pre-ligand clusters in the resting cells. Upon tumor necrosis factor (TNF) stimulation, the diffusion coefficient of membrane TNFR1 was significantly decreased and a substantial level of TNFR1 undergoes oligomerization to form trimers and hexamers. Moreover, multi-color cell imaging reveals that both digital and graded information processing regulate NF-κB activation across different TNFR1 expression levels. Our results indicate that single-cell NF-κB activation potential strongly correlates with its TNFR1 characteristics.
Project description:Multiple sclerosis is an autoimmune disease of the central nervous system (CNS) mediated by CD4+ T cells and modeled via experimental autoimmune encephalomyelitis (EAE). Inhibition of PRMT5, the major Type II arginine methyltransferase, suppresses pathogenic T cell responses and EAE. PRMT5 is transiently induced in proliferating memory inflammatory Th1 cells and during EAE. However, the mechanisms driving PRMT5 protein induction and repression as T cells expand and return to resting is currently unknown. Here, we used naive mouse and memory mouse and human Th1/Th2 cells as models to identify mechanisms controlling PRMT5 protein expression in initial and recall T cell activation. Initial activation of naive mouse T cells resulted in NF-κB-dependent transient Prmt5 transcription and NF-κB, mTOR and MYC-dependent PRMT5 protein induction. In murine memory Th cells, transcription and miRNA loss supported PRMT5 induction to a lesser extent than in naive T cells. In contrast, NF-κB/MYC/mTOR-dependent non-transcriptional PRMT5 induction played a major role. These results highlight the importance of the NF-κB/mTOR/MYC axis in PRMT5-driven pathogenic T cell expansion and may guide targeted therapeutic strategies for MS.
Project description:Scutellarein (SCU) is a well-known flavone with a broad range of biological activities against several cancers. Human hepatocellular carcinoma (HCC) is major cancer type due to its poor prognosis even after treatment with chemotherapeutic drugs, which causes a variety of side effects in patients. Therefore, efforts have been made to develop effective biomarkers in the treatment of HCC in order to improve therapeutic outcomes using natural based agents. The current study used SCU as a treatment approach against HCC using the HepG2 cell line. Based on the cell viability assessment up to a 200 μM concentration of SCU, three low-toxic concentrations of (25, 50, and 100) μM were adopted for further investigation. SCU induced cell cycle arrest at the G2/M phase and inhibited cell migration and proliferation in HepG2 cells in a dose-dependent manner. Furthermore, increased PTEN expression by SCU led to the subsequent downregulation of PI3K/Akt/NF-κB signaling pathway related proteins. In addition, SCU regulated the metastasis with EMT and migration-related proteins in HepG2 cells. In summary, SCU inhibits cell proliferation and metastasis in HepG2 cells through PI3K/Akt/NF-κB signaling by upregulation of PTEN, suggesting that SCU might be used as a potential agent for HCC therapy.
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:ObjectiveMacrophage accumulation in adipose tissue (AT) during obesity contributes to inflammation and insulin resistance. Recruitment of monocytes to obese AT has been the most studied mechanism explaining this accumulation. However, recent evidence suggests that recruitment-independent mechanisms may also regulate pro-inflammatory AT macrophage (ATM) numbers. The role of increased ATM survival during obesity has yet to be explored.ResultsWe demonstrate that activation of apoptotic pathways is significantly reduced in ATMs from diet-induced and genetically obese mice. Concurrently, pro-survival Bcl-2 family member protein levels and localization to the mitochondria is elevated in ATMs from obese mice. This increased pro-survival signaling was associated with elevated activation of the transcription factor, NF-κB, and increased expression of its pro-survival target genes. Finally, an obesogenic milieu increased ATM viability only when NF-κB signaling pathways were functional.ConclusionsOur data demonstrate that obesity promotes survival of inflammatory ATMs, possibly through an NF-κB-regulated mechanism.
Project description:Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumor; GBM's inevitable recurrence suggests that glioblastoma stem cells (GSC) allow these tumors to persist. Our previous work showed that FOSL1, transactivated by the STAT3 gene, functions as a tumorigenic gene in glioma pathogenesis and acts as a diagnostic marker and potential drug target in glioma patients. Accumulating evidence shows that STAT3 and NF-κB cooperate to promote the development and progression of various cancers. The link between STAT3 and NF-κB suggests that NF-κB can also transcriptionally regulate FOSL1 and contribute to gliomagenesis. To investigate downstream molecules of FOSL1, we analyzed the transcriptome after overexpressing FOSL1 in a PDX-L14 line characterized by deficient FOSL1 expression. We then conducted immunohistochemical staining for FOSL1 and NF-κB p65 using rabbit polyclonal anti-FOSL1 and NF-κB p65 in glioma tissue microarrays (TMA) derived from 141 glioma patients and 15 healthy individuals. Next, mutants of the human FOSL1 promoter, featuring mutations in essential binding sites for NF-κB were generated using a Q5 site-directed mutagenesis kit. Subsequently, we examined luciferase activity in glioma cells and compared it to the wild-type FOSL1 promoter. Then, we explored the mutual regulation between NF-κB signaling and FOSL1 by modulating the expression of NF-κB or FOSL1. Subsequently, we assessed the activity of FOSL1 and NF-κB. To understand the role of FOSL1 in cell growth and stemness, we conducted a CCK-8 assay and cell cycle analysis, assessing apoptosis and GSC markers, ALDH1, and CD133 under varying FOSL1 expression conditions. Transcriptome analyses of downstream molecules of FOSL1 show that NF-κB signaling pathway is regulated by FOSL1. NF-κB p65 protein expression correlates to the expression of FOSL1 in glioma patients, and both are associated with glioma grades. NF-κB is a crucial transcription factor activating the FOSL1 promoter in glioma cells. Mutual regulation between NF-κB and FOSL1 contributes to glioma tumorigenesis and stemness through promoting G1/S transition and inhibiting apoptosis. Therefore, the FOSL1 molecular pathway is functionally connected to NF-κB activation, enhances stemness, and is indicative that FOSL1 may potentially be a novel GBM drug target.
Project description:Elevations in plasma levels of pro-inflammatory cytokines and C-reactive protein (CRP) in patient blood have been associated with impairments in cognitive abilities and more severe psychiatric symptoms in people with schizophrenia. The transcription factor nuclear factor kappa B (NF-κB) regulates the gene expression of pro-inflammatory factors whose protein products trigger CRP release. NF-κB activation pathway mRNAs are increased in the brain in schizophrenia and are strongly related to neuroinflammation. Thus, it is likely that this central immune regulator is also dysregulated in the blood and associated with cytokine and CRP levels. We measured levels of six pro-inflammatory cytokine mRNAs and 18 mRNAs encoding NF-κB pathway members in peripheral blood leukocytes from 87 people with schizophrenia and 83 healthy control subjects. We then assessed the relationships between the alterations in NF-κB pathway genes, pro-inflammatory cytokine and CRP levels, psychiatric symptoms and cognition in people with schizophrenia. IL-1β and IFN-γ mRNAs were increased in patients compared to controls (both p < 0.001), while IL-6, IL-8, IL-18, and TNF-α mRNAs did not differ. Recursive two-step cluster analysis revealed that high levels of IL-1β mRNA and high levels of plasma CRP defined 'high inflammation' individuals in our cohort, and a higher proportion of people with schizophrenia were identified as displaying 'high inflammation' compared to controls using this method (p = 0.03). Overall, leukocyte expression of the NF-κB-activating receptors, TLR4 and TNFR2, and the NF-κB subunit, RelB, was increased in people with schizophrenia compared to healthy control subjects (all p < 0.01), while NF-κB-inducing kinase mRNAs IKKβ and NIK were downregulated in patients (all p < 0.05). We found that elevations in TLR4 and RelB appear more related to inflammatory status than to a diagnosis of schizophrenia, but changes in TNFR2 occur in both the high and low inflammation patients (but were exaggerated in high inflammation patients). Further, decreased leukocyte expression of IKKβ and NIK mRNAs was unique to high inflammation patients, which may represent schizophrenia-specific dysregulation of NF-κB that gives rise to peripheral inflammation in a subset of patients.