Endothelial cell activation driven by CD4+ memory T cells produced soluble factors
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ABSTRACT: In this project we analyzed whole transcriptome changes in endothelial cells (ECs) in response to stimulation with activated CD4+ memory T cells produced factors. Given the central role of NF-κB signaling in EC activation we treated cells with inhibitors for canonical NF-κB signaling (IKKβ inhibitor, iIKKβ) and non-canonical NF-κB signaling (NF-κB inducting kinase (NIK) inhibitor, iNIK). Cells were stimulated 72h with conditioned medium (hereafter called Tm sup = 50% culture supernatant from aCD3/aCD28 activated CD4+ memory T cells; 50% RMPI supplemented with 10% FCS) and treated with iIKKβ, iNIK or DMSO as a control. Other controls taken along were unstimulated DMSO treated ECs and unstimulated untreated ECs.
Project description:The balance between laminins containing the α5 (LAMA5) or the α4 (LAMA4) subunits is determinant for the diapedesis of different leukocyte subtypes in inflammatory conditions. We have shown that the extracellular superoxide dismutase (SOD3) is a positive regulator of LAMA4, and this was associated with enhanced intratumor T cell infiltration in experimental and primary human cancers. Here we show that SOD3 overexpression in neoplastic or endothelial cells (ECs) downmodulates LAMA5 levels in implanted tumors. The inhibitory effect of SOD3 on LAMA5 expression occurs at the transcriptional level and is specific for SOD3, since LAMA5 levels are not changed by in SOD1-overexpressing cells. Global transcriptomic analyses revealed that SOD3 overexpression changes the transcription of 1,682 genes in ECs exposed to tumor secreted factors, being the canonical and non-canonical Nuclear Factor kappa B (NF-κB) pathways major SOD3 targets. Indeed, SOD3 reduced the transcription of well-known NF-κB target genes as well as the NF-κB-driven promoter activity in endothelial cells stimulated with tumor necrosis factor (TNF)-α, an inducer of NF-κB signaling
Project description:Mesenchymal stem cells (MSCs) are known to induce the conversion of activated T-cells into regulatory T-cells in vitro. The marker CD69 is a target of canonical NF-κB signaling and is transiently expressed upon activation; however, stable CD69 expression defines cells with immunoregulatory properties. Given its enormous therapeutic potential, we explored the molecular mechanisms underlying the induction of regulatory cells by MSCs. Peripheral blood CD3+ T-cells were activated and cultured in the presence or absence of MSCs. CD4+ cell mRNA expression was then characterized by microarray analysis. The drug BAY11-7082 and a siRNA against RELB were used to explore the differential roles of canonical and non-canonical NF-κB signaling, respectively. Flow cytometry and real-time PCR were used for analyses. Genes with immunoregulatory functions, CD69 and non-canonical NF-κB subunits (RELB and NFKB2) were all expressed at higher levels in lymphocytes co-cultured with MSCs. The frequency of CD69+ cells among lymphocytes cultured alone progressively decreased after activation. In contrast, the frequency of CD69+ cells increased significantly following activation in lymphocytes co-cultured with MSCs. Inhibition of canonical NF-κB signaling by BAY immediately following activation blocked the induction of CD69; however, inhibition of canonical NF-κB signaling on the 3rd day further induced the expression of CD69. Furthermore, late expression of CD69 was inhibited by RELB siRNA. These results indicate that the canonical NF-κB pathway controls the early expression of CD69 after activation; however, in an immunoregulatory context, late and sustained CD69 expression is promoted by the non-canonical pathway and is inhibited by canonical NF-κB signaling. In order to study the molecular basis by which Multipotent Mesenchymal Stromal/Stem Cells (MSC) exert their immune regulatory function, immunomagnetically purified CD3+ T-cells from the peripheral blood of 3 individuals were activated and cultured in the presence or absence of MSCs. Following 5 days, CD4+ and CD8+ T-cells were further immunomagnetically selected and their gene expression profiles were obtained by microarrays and compared. Paired samples from 3 individuals were used for this analysis.
Project description:To identify conserved TNFα-induced changes in chromatin-accessibility in mammals, we performed ATAC-seq in primary vascular endothelial cells (ECs) isolated from the aortas of human (HAEC), mouse (MAEC) and cow (BAEC), before and after TNFα. We overlay our data with multi-species NF-κB binding data and identify multiple modes of NF-κB-chromatin interactions that are conserved during mammalian TNFα response. Our cross-species approach identifies conserved changes in chromatin-accessibility at NF-κB binding sites that are disease-relevant and essential during mammalian acute inflammation.
Project description:To understand the mechanism of Pikfyve inhibition in dendritic cells, we cultured conventional dendritic cells isolated from the bone marrow of wild-type mice and performed transcriptome profiling on RNA extracted from cells treated with DMSO or apilimod for 3 or 8 hours on Day 6 in culture. Taken together, these data demonstrate the PIKfyve mediates suppression of DC transcriptional maturation programs through the alternate/non-canonical NF-κB regulatory pathway.
Project description:The NF-κB pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-κB signaling is well studied, there is little information on the divergent non-canonical NF-κB pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-κB inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-κB components p100 to p52, and accumulation of RelB. Tumor necrosis factor α (TNFα) and receptor activator of NF-κB ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-κB transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity. We identify a role for Nuclear Factor inducing κB (NIK) in pancreatic beta cell failure. NIK activation disrupts glucose homeostasis in zebrafish in vivo and impairs glucose-stimulated insulin secretion in mouse and human islets in vitro. NIK activation also perturbs beta cell insulin secretion in a diet-induced obesity mouse model. These studies reveal that NIK contributes a central mechanism for beta cell failure in obesity. To uncover the role of NIK in pancreatic beta cells, we performed a gene expression microarray analysis comparing pancreatic islets with constitutive beta cell intrinsicNIK activation from the 16 week old mice (beta cell specific TRAF2 and TRAF2 knockout mice) to their controls (n=3 per group).
Project description:IKKα, encoded by CHUK, is crucial in the non-canonical NF-κB pathway and part of the IKK complex activating the canonical pathway alongside IKKβ. The absence of IKKα causes fetal encasement syndrome in humans, fatal in utero, while an impaired IKKα-NIK interaction was reported in a single patient and causes combined immunodeficiency. Here, we describe compound heterozygous variants in the kinase domain of IKKα in a female patient with hypogammaglobulinemia, recurrent lung infections, and Hay-Wells syndrome-like features. We showed that both variants were loss-of-function. Non-canonical NF-κB activation was profoundly diminished in stromal and immune cells while the canonical pathway was unexpectedly partially impaired. Reintroducing wt CHUK restored non-canonical NF-κB activation. The patient had neutralizing autoantibodies against type I IFN, akin to non-canonical NF-κB pathway deficiencies. Thus, this is the first case of biallelic CHUK mutations disrupting IKKα kinase function, broadening non-canonical NF-κB defect understanding, and suggesting IKKα's role in canonical NF-κB target gene expression in humans.
Project description:The malignant cells of Hodgkin's lymphoma are characterized by a constitutive activation of the canonical as well as the non-canonical NF-κB signaling cascades. We carried out genome-wide localization and expression profiling experiments in the Hodgkin lymphoma cell line L1236 for the canonical and non-canonical NF-κB pathway components p65, p50 and p52, RelB, respectively. We found that the single NF-κB subunits bind to overlapping, but distinct cistromes by using consensus motifs of high similarity.
Project description:TNFα has an evolutionary conserved role in mediating inflammation via activation of the transcription factor NF-κB. The functions of individual NF-κB binding sites are not well understood. To identify conserved and functionally important NF-κB binding sites in mammals, we performed ChIP-seq to map the genome-wide binding of RELA and select histone modifications in primary vascular endothelial cells (ECs) isolated from the aortas of human (HAEC), mouse (MAEC) and cow (BAEC), before and after TNFα. The conserved RELA binding sites show strong epigenetic changes in response to TNFα and enrich near genes controlling vascular development and pro-inflammatory responses. Our method identifies novel modes of RELA-chromatin interactions that are conserved in mammals and shared between multiple cell-types. Particularly, genomic regions bound by RELA prior to stimulation are important responders during TNFα stimulation. We use CRISPR/Cas9 genome editing to validate the roles of the conserved RELA pre-bound sites near pro-inflammatory genes such as CCL2 and PLK2. Our evolutionary approach describes new aspects of mammalian NF-κB biology including its role within super-enhancers and relevance in inflammatory disorders.
Project description:Pro-inflammatory cytokines were shown to promote growth and survival of cancerous cells. TNF induced RelA:p50 NF-κB dimer via the canonical pathway is thought to link inflammation with cancer. Integrating biochemical and computational studies we identify that deficiency of non-canonical signal transducer p100 triggers a positive autoregulatory loop, which instead perpetuates an alternate RelB:p50 containing NF-κB activity upon TNF treatment. TNF stimulated RelB:p50 dimer is sufficient for mediating NF-κB target gene-expressions and suppressing apoptotic cellular death independent of principal NF-κB subunit RelA. We further demonstrate that activating mutations in non-canonical NF-κB module deplete multiple myeloma cells of p100, thereby, provoking autoregulatory RelB:p50 activation. Finally, autoregulatory control reinforces protracted pro-survival NF-κB response, albeit comprising of RelB:p50, upon TNF priming that protects myeloma cells with dysfunctional p100 from subsequent apoptotic insults. In sum, we present evidence for positive autoregulation mediated through the NF-κB system and its potential involvement in human neoplasm.
Project description:Aim: Use microarray analysis to understand the molecular mechanism underlying the effect of aristolochic acid (AA), a major active component of plants from the Aristolochiaceae family, in normal human kidney (HK-2) cells. Methods: HK-2 cells were treated with AA for 24 hours and cell viability was measured by a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. Complementary DNA microarrays were used to investigate the gene expression pattern of HK-2 cells exposed to AA and the results of this study were in triplicate. Quantitative real-time RT-PCR assay was used to verify the microarray data for selected nuclear factor kappa B (NF-κB)-regulated genes. Furthermore, subcellular localization of NF-κB p65 was visualized by immunofluorescence confocal microscopy in HK-2 cells. NF-κB activity was examined by luciferase reporter assay in HK-2/NF-κB transgenic cells. Results: AA exhibited a dose-dependent cytotoxic effect in HK-2 cells and induced alterations in gene expression profiles related to DNA damage response, stress response, etc. In addition, 9 biological pathways associated with immunomodulatory functions were down-regulated in AA-treated HK-2 cells. Network analysis revealed that NF-κB played a central role in the network topology. Among NF-kB-regulated genes, 8 differentially expressed genes were verified by real-time RT-PCR. The inhibition of NF-κB activity by AA was further confirmed by immunofluorescence confocal microscopy and by NF-κB luciferase reporter assay. Conclusion: Our data revealed that AA could suppress NF-κB activity in normal human cells, perhaps partially accounting for the reported anti-inflammatory effects of some plants from the genus Aristolochia. HK-2 cells were grown in keratinocyte serum-free basal medium (Gibco) supplemented with 5 ng/ml of recombinant epidermal growth factor and 50 μg/ml of bovine pituitary extract without antibiotics in 5 % CO2 at 370C. HK-2 cells were seeded in 25-T flasks and incubated for 24 h before aristolochic acid treatment. Aristolochic acid (10 90 μM) were added to HK-2 cells for 24 h. The control cells received equal amounts of water only.