NF-kB Dependent Pathway Research Articles

Abstract P382: Epigenetic Regulation of the NF-kB Pathway by the Neural-Hematopoietic-Inflammatory Axis as a Potential Link Between Psychosocial Stress and Cardiovascular Risk: Data From the Washington DC Cardiovascular Health and Needs Assessment

Introduction: Chronic psychosocial stress (cPSS) is associated with cardiovascular disease (CVD) risk, caused in part by dysregulation of the neural-hematopoietic-inflammatory axis and epigenetic changes. cPSS may also affect NF-kB dependent pathways, suggesting a potential link to accelerated CVD risk and health inequities for populations most impacted by adverse social determinants. Hypothesis: We propose cPSS associates with greater amygdala activity (AmygA), a stress marker, and splenic activity (SpleenA), a hematopoietic activation measure. This relates to higher pro-inflammatory cytokine levels, partially due to less DNA methylation of NF-kB pathway-related genes. Methods: 60 African American adults (93.3% female, mean age 61) with CVD risk, living in the Washington, D.C. area underwent 18 FDG PET/CT to evaluate AmygA and SpleenA. DNA methylation analysis assessed epigenetic associations of the NF- κ B1/2 gene in PBMCs and ELISA- measured serum IL-1β and TNFα. Multivariable regression analysis adjusted for atherosclerotic CVD 10-year risk score and BMI was used to examine associations. Results: Greater AmygA and SpleenA were significantly associated with one another (β=0.26; p=0.003) and both were associated with greater pro-inflammatory cytokines IL1-β (AmygA:β =0.36, SpleenA:β=0.72, p<0.05) and TNF-α (AmygA:β=0.31, SpleenA:β=0.58, p<0.05). Further, we identified 2 significant methylation sites out of 81 on the NF- κ B1/2 gene. Notably, AmygA and SpleenA were inversely associated with the NF-κB1 cg01983105 and cg07955720 methylation sites (Table). Conclusions: We highlight a possible link between AmygA and SpleenA with decreased DNA methylation of the NF- κB gene. Our findings demonstrate a potential relationship between chronic stress-related neural activity and CVD risk through immune function and epigenetic alterations. These results should be examined in larger, diverse population-based cohorts with longitudinal data to identify intervention targets for reducing health inequities.

Heme induces significant neutrophil adhesion in vitro via an NFκB and reactive oxygen species-dependent pathway.

Intravascular hemolysis, a major manifestation of sickle cell disease (SCD) and other diseases, incurs the release of hemoglobin and heme from red blood cells, in turn triggering inflammatory processes. This study investigated the in vitro effects of heme, a major inflammatory DAMP, on the adhesive properties of isolated human neutrophils. Heme (20 and 50µM) significantly increased the adhesion of neutrophils to fibronectin and to recombinant ICAM-1, under static conditions, even more efficiently than the potent pro-inflammatory cytokine, tumor necrosis factor-α (TNF); a microfluidic assay confirmed that heme stimulated neutrophil adhesion under conditions of shear stress. Heme-induced neutrophil adhesion was associated with the increased activities, but not expressions, of the Mac-1 and LFA-1 integrin subunits, CD11b and CD11a, on the cell surface. Notably, heme (50µM) significantly induced NFκB translocation in neutrophils, and inhibition of NFκB activity with the BAY11-7082 molecule abolished heme-induced cell adhesion to fibronectin and significantly decreased CD11a activity. Flow cytometric analysis demonstrated major reactive oxygen species (ROS) generation in neutrophils following heme stimulation that could be inhibited by the antioxidant, α-tocopherol, and by BAY11-7082. Furthermore, co-incubation with α-tocopherol abrogated both heme-stimulated neutrophil adhesion and CD11a/CD11b activation. Thus, our data indicate that heme, at clinically relevant concentrations, is a potent activator of neutrophil adhesion, increasing the ligand affinity of the β2 integrins via a mechanism that may be partially mediated by an NFkB-dependent pathway and the generation of ROS. Given the fundamental role that the adhesion of neutrophils to the vascular wall plays in SCD vaso-occlusion and other vascular inflammatory processes, our findings provide further evidence that cell-free heme is a major therapeutic target in the hemolytic diseases.

Multifaceted effect of caffeic acid against Streptococcus mutans infection: microbicidal and immunomodulatory agent in macrophages.

The aim of the present study was to investigate the effects of caffeic acid in the interface between the antimicrobial and anti-inflammatory function in macrophage response against S. mutans. S. mutans (108cfu/mL) were incubated with caffeic acid to determinate the half-maximal inhibitory concentration (IC50) and macrophage cells were incubated with caffeic acid to determinate cell viability and toxicity. Anti-inflammatory effects were measured by nitrite accumulation, TNF-α and PGE2 production, and NF-kB phosphorylation, and S. mutans survival following internalization by macrophages was investigated. We found that caffeic acid presented antimicrobial activity against S. mutans (IC50 = 2.938 ± 0.1225mM) without exerting cytotoxicity. Caffeic acid inhibited nitrite, TNF-α and PGE2 production by the NF-kB dependent pathway, indicating an immunomodulatory property. Caffeic acid also contributed to macrophage bacteria clearance activity. In summary, caffeic acid presented antimicrobial activity against S. mutans and anti-inflammatory effects in macrophages.

Heme Induces Significant Neutrophil Adhesion in Vitro Via an Nfκb-Dependent Pathway

Background: Intravascular hemolysis, a major complication of sickle cell anemia and malaria among other diseases, incurs the release of excessive quantities of hemoglobin and heme from red blood cells. If not adequately sequestered by hemoglobin- and heme-binding proteins, these molecules may incur oxidative stress, thrombosis and cellular activation. Heme is now recognized as a red cell DAMP (damage-associated molecular pattern) that stimulates inflammasome formation in macrophages and can induce neutrophil extracellular trap release under certain circumstances. Aim: This study evaluated the in vitro effects of heme on the adhesive properties of human neutrophils. Methods: Neutrophils were separated from the peripheral blood of healthy individuals and their adhesion in the presence/absence of heme was compared by static adhesion assays using myeloperoxidase, for quantification of cell adhesion (30 min, 37oC, 5% CO2). Results: Heme (50 µM) significantly increased the adhesion of neutrophils to fibronectin (FN) and to recombinant ICAM-1 (an endothelial ligand), when compared to non-treated neutrophils (43.7±4.6%; 10.9±21.4 %, respectively, n=5, P<0.001 for FN and 38.1±3.6%; 6.9±0.8%, respectively, n=6, P<0.001 for ICAM-1). Interestingly, heme induced neutrophil adhesion even more efficiently than the potent pro-inflammatory cytokine, TNF-α (200 ng/ml) (35.5±5.2% adhesion to FN, n=6, P<0.05). Furthermore, inhibition of the NFκB transcription factor with the pharmacological inhibitor, BAY 11-7082 (20 μM), abolished heme-stimulated neutrophils adhesion to FN (reduced from 41.8±6.7% to 7.4±0.5%. n=6; P<0.001). Flow cytometry demonstrated that while TNF-α significantly increases the expression of the Mac-1 integrin subunit, CD11b (data not shown, P<0.05), but not the LFA-1 integrin subunit CD11a (data not shown, P>0.05), on the surface of neutrophils, heme did not augment CD11b or CD11a expression (P>0.05). In contrast, heme significantly augmented the active conformations of these two β2 integrin subunits, as demonstrated by epitope-specific antibodies (CD11b; heme: 520.5±51.8; basal 123.7±16.7 MFI, n=10, P<0.001 and CD11a; heme: 69.8±3.9; basal: 43.8±2.0 MFI, n=6, P>0.001). Inhibition of NFκB translocation with BAY 11-7082 (20 μM) significantly decreased the activity of the LFA-1 integrin on the surface of neutrophils after heme stimulation (reduced to 47.6±4.2 MIF, n=6; P<0.05). To assess whether heme-induced neutrophil adhesive properties are mediated by cytoskeletal rearrangements, we evaluated the effects of cytochalasin D (0.5 μg/ml), an inhibitor of actin polymerization. While cytochalasin D inhibited TNF-α-induced neutrophils adhesion (data not shown, P<0.05), this compound did not significantly alter the adhesive properties of heme-stimulated neutrophils to FN (heme: 22.8±2.3%, p<0.001; cytochalasin D: 22.5±2.0%, p=0.4; n=6). Pre-incubation of heme-stimulated neutrophils with the antioxidants, ascorbic acid (120 µM; 3.5 hours) and α-tocopherol (1mM; 15 min), reduced their adhesion to FN by 14.4±9.2% and 46.5±5.5% respect. n=6, p<0.05). Conclusion: We therefore demonstrate, herein, that heme is a potent activator of neutrophil adhesive properties, increasing the ligand affinity of the β2 integrins via a mechanism that is apparently mediated by an NFkB-dependent pathway. The mechanism of neutrophil activation appears to differ from that stimulated by TNF-α and may involve, in part, the generation of reactive oxygen species. Given the fundamental role that the adhesion of neutrophils to the vascular wall plays in the vaso-occlusive process in sickle cell disease and other vascular inflammatory processes, our findings further support the idea that cell-free heme represents a major therapeutic target in the hemolytic diseases. DisclosuresNo relevant conflicts of interest to declare.

DNAJA4 deficiency enhances NF-kappa B-related growth arrest induced by hyperthermia in human keratinocytes

BackgroundHyperthermia is an effective treatment against cancer and human papillomavirus (HPV) infection. Previous studies have shown that heat shock proteins are crucial to the action of hyperthermia. ObjectivesTo examine the effects of hyperthermia in combination with DNAJA4-deficiency on human keratinocytes and Condyloma acumunatum (CA) tissues. MethodsHaCaT cells were subjected to 44°C (compared to 37°C) waterbath for 30min for stimulation. Foreskin or CA tissues obtained from patients undergoing circumcision or pathological examination were bisected and subjected to similar treatments. DNAJA4-knockout (KO) HaCaT cells were generated with CRISPR/Cas9 technology. mRNA and protein expressions were determined using rt-qPCR and western-blotting. Cell cycle distribution, apoptosis and senescence were analyzed by flow cytometry. ResultsDNAJA4 was induced in HaCaT cells, foreskin and CA tissues subjected to hyperthermia at both transcriptional and translational levels. NF-kB,33NF-kB: nuclear factor-kappa B. was activated by hyperthermia in HaCaT cells, and further enhanced by DNAJA4-deficiency. Transcription of TNF-α44TNF-α: tumor necrosis factor-alpha.; IL-1B,55IL-1B: interleukin-1 beta. TNFAIP366TNFAIP3: Tumor necrosis factor alpha-induced protein 3. and IL-877IL-8: interleukin-8. were induced in HaCaT cells subjected to hyperthermia. DNAJA4-knockout promoted transcriptions of TNF-α and IL-1B, whereas decreased that of TNFAIP3 and IL-8. Reduced cell survival, proliferation and viability were demonstrated using flow cytometry and MTS assays. Furthermore, NF-kB inhibitors reversed most of the phenotypes observed. ConclusionsHyperthermia reduced HaCaT cell proliferation and promoted cytokine expressions responsible for anti-viral activity, mainly through a NF-kB dependent pathway. DNAJA4-deficiency enhanced the activation of NF-kB by hyperthermia in HaCaT cells, indicating that DNAJA4 may be a promising therapeutic target for use in the treatment of cutaneous HPV infections.

Weighted Gene Co-expression Network Analysis Identifies FKBP11 as a Key Regulator in Acute Aortic Dissection through a NF-kB Dependent Pathway

Acute aortic dissection (AAD) is a life-threatening disease. Despite the higher risk of mortality, currently there are no effective therapies that can ameliorate AAD development or progression. Identification of meaningful clusters of co-expressed genes or representative biomarkers for AAD may help to identify new pathomechanisms and foster development of new therapies. To this end, we performed a weighted gene co-expression network analysis (WGCNA) and calculated module-trait correlations based on a public microarray dataset (GSE 52093) and discovered 9 modules were found to be related to AAD. The module which has the strongest positive correlation with AAD was further analyzed and the top 10 hub genes SLC20A1, GINS2, CNN1, FAM198B, MAD2L2, UBE2T, FKBP11, SLMAP, CCDC34, and GALK1 were identified. Furthermore, we validated the data by qRT-PCR in an independent sample set originated from our study center. Overall, the qRT-PCR results were consistent with the results of the microarray analysis. Intriguingly, the highest change was found for FKBP11, a protein belongs to the FKBP family of peptidyl-prolyl cis/trans isomerases, which catalyze the folding of proline-containing polypeptides. In congruent with the gene expression analysis, FKBP11 expression was induced in cultured endothelial cells by angiotensin II treatment and endothelium of the dissected aorta. More importantly we show that FKBP11 provokes inflammation in endothelial cells by interacting with NF-kB p65 subunit, resulting in pro-inflammatory cytokines production. Accordingly, siRNA mediated knockdown of FKBP11 in cultured endothelial cells suppressed angiotensin II induced monocyte transmigration through the endothelial monolayer. Based on these data, we hypothesize that pro-inflammatory cytokines elicited by FKBP11 overexpression in the endothelium under AAD condition could facilitate transendothelial migration of the circulating monocytes into the aorta, where they differentiate into active macrophages and secrete MMPs and other extracellular matrix (ECM) degrading proteins, contributing to sustained inflammation and AAD. Taken together, our data identify important role of FKBP11 which can serve as biomarker and/or therapeutic target for AAD.

Macrophage-derived nitric oxide initiates T-cell diapedesis and tumor rejection

ABSTRACTIn tumor biology, nitric oxide (NO) is generally regarded as an immunosuppressive molecule that impedes T-cell functions and activation of endothelial cells. Contrasting with this view, we here describe a critical role for NO derived from inducible nitric oxide (iNOS)-expressing tumor macrophages in T-cell infiltration and tumor rejection as shown by iNOS gene deletion, inhibition of iNOS, or NO donors. Specifically, macrophage-derived NO was found to induce on tumor vessels adhesion molecules that were required for T-cell extravasation. Experiments with human endothelial cells revealed a bimodal dose-dependent effect of NO. High doses of NO donors were indeed suppressive but lower, more physiological concentrations, induced adhesion molecules in an NFkB-dependent pathway and preferentially activated transcription of genes involved in lymphocyte diapedesis. iNOS+ macrophages in tumors appear to generate precisely the amount of NO that promotes endothelial activation and T-cell infiltration. These results will be valuable for the development of strategies designed to overcome the paucity of T-cell infiltration into tumors that is a major obstacle in clinical cancer immunotherapy.

Abstract 567: Transcription Factor Runx2 is Induced in Vascular Aging and May Promote Age-related Arterial Stiffness

Background: Arterial stiffening is a hallmark of vascular aging and may constitute a critical mechanism linking age to increased cardiovascular risk. However, up to now there is no therapy available to efficiently and specifically target age-related arterial stiffening. We recently identified the osteogenic transcription factor Runx2 as an inducer of diabetic arterial stiffness. Objective: The present study investigated the role of Runx2 in the setting of age-related arterial stiffness. Methods and Results: Aortic stiffness – quantified by ex vivo mechanical testing (pressure myography) – was markedly increased in 1-year old male C57Bl/6 mice compared to young (10 week-old) controls. At the same time, Runx2 was aberrantly upregulated in the medial layer of aged aortae, coming along with significant medial fibrosis. Additionally, we detected increased aortic expression of interleukin 6 ( Il6 ) – a key cytokine involved in vascular “inflammaging”. Mechanistically, we found IL-6-induced RUNX2 expression in aortic smooth muscle cells (SMCs) via a NFkB-dependent pathway. Conclusion: In conclusion this study suggests Runx2 as a potential mediator of age-related arterial fibrosis and stiffness warranting further interventional/therapeutic studies.

Central role for protein kinase C in oxytocin and epidermal growth factor stimulated cyclooxygenase 2 expression in human myometrial cells.

BackgroundProstaglandins are important mediators of uterine contractility and cervical ripening during labour. Cyclooxygenase-2 (COX-2), also known as prostaglandin-endoperoxide synthase 2, is a rate limiting enzyme involved in the conversion of arachidonic acid into prostaglandins at parturition. In this paper, the pathways underlying agonist-induced cyclooxygenase-2 expression in human myometrial cells were studied.ResultsMyometrial cells were stimulated with different agonists: oxytocin (OXT), epidermal growth factor (EGF), interleukin-1β (IL1β), and phorbol-12-myristate-13-acetate (PMA) alone and in the presence of specific signalling pathway inhibitors. The nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB) pathway was inhibited by means of the IKK-2 inhibitor TPCA-1. Signalling through extracellular signal-regulated kinases (ERK) was inhibited using the MEK1/2 inhibitor PD-184352. Bisindolylmaleimide-I was used to inhibit protein kinase C (PKC) signalling. COX-2 expression and ERK phosphorylation were measured using immunoblotting.OXT induced COX-2 expression by activating PKC and ERK. EGF increased COX-2 expression via stimulation of PKC, ERK and NFKB. As expected, the pro-inflammatory cytokine IL1β induced COX-2 expression by activating PKC- and NFKB-dependent pathways. Stimulation of PKC directly with PMA provoked strong COX-2 expression.ConclusionsPKC plays a central role in OXT and EGF induced COX-2 expression in human myometrial cells. However, other pathways, notably ERK and NFKB are also involved to an extent which depends on the type of agonist used.

Adipocytokine resistin induces tissue factor expression in human coronary artery endothelial cells via NF kB-dependent pathway

Objective: Atherosclerosis is characterized by endothelial inflammation and dysfunction. Adipose tissue has been increasingly recognized as an active endocrine organ secreting so-called adipokines, and among them resistin, recently described and not yet extensively studied, has been defined as a novel inflammatory marker in atherosclerosis. The pathophysiology underlying this interplay, however, remains not completely characterized. Aim of the study is to determine whether resistin might affect prothrombotic characteristics of human coronary artery endothelial cells (HCAECs). Methods and results: Incubation of HCAECs with resistin caused up-regulation of the Tissue Factor (TF) expression as demonstrated by FACS analysis. Moreover, TF activity was induced in a dose dependent manner, as shown by real time PCR and by a colorimetric assay. Resistin-induced TF expression was mediated by oxygen free radicals through the activation of the transcription factor, nuclear factor-kappa B (NF-kB), as demonstrated by electrophoretic mobility shift assay and by suppression of TF expression by superoxide dismutase, catalase, and by NF-kB inhibitors, PDTC and BAY 11-7082. ![Figure][1] Conclusions: These data confirm the hypothesis that resistin may contribute to athero-thrombosis exerting direct effects on HCAECs by promoting TF expression, thus representing an effector molecule able to induce a pro-thrombotic phenotype in cells present in the vessel wall. [1]: pending:yes

Abstract 310: GLP-1 Cleavage Product (9-36)-NH2 Exerts Pro-survival Effects on Smooth Muscle Cells in Advanced Inflammatory Hemodynamic Conditions

Glucagon-like peptide-1(GLP-1), an incretin hormone, has been shown to have atheroprotective effects on the cardiovascular system in animal models of atherosclerosis and diabetes, and in several clinical trials. These beneficial effects are presumed to occur through active GLP-1 (7-36)-NH2/(7-37), and its receptor GLP-1R; however, within minutes GLP-1 (7-36)-NH2/(7-37) becomes cleaved and inactivated by DPP4 into its smaller metabolite, GLP-1 (9-36)-NH2(9-37). It still remains unclear how GLP-1 (7-36)-NH2/(7-37), its metabolites, and GLP-1R provide beneficial vascular effects. We sought to elucidate the role of GLP-1 on vessel wall health using a novel in vitro human surrogate system that cocultures human endothelial (EC) and smooth muscle cells (SMCs) and applies human hemodynamics from the carotid bifurcation, a site prone to developing atherosclerosis, combined with other atherogenic factors (oxidized LDL, TNFα). Though, we found GLP-1R to be highly expressed in ECs and SMCs from both healthy and advanced inflammatory vascular environments, atheroprotective effects from the addition of GLP-1 (7-36)-NH2 or (9-36)-NH2 acted primarily on SMCs. In SMCs from atherogenic hemodynamic conditions, GLP-1 (7-36)-NH2 reduced NFkB activity and increased the anti-oxidant response protein, HO-1, via GLP-1R. A novel finding was that the cleaved metabolite, GLP-1 (9-36)-NH2, elicited the same response. Though GLP-1 (9-36)-NH2 did not alter downstream inflammatory gene expression, the NFkB-dependent pathways converged on pro-survival signaling since the metabolite GLP-1 (9-36)-NH2 uniquely decreased apoptotic signaling, including cleaved Caspase-3. These same responses were not seen with cleavage-resistant forms of GLP-1 (7-36)-NH2, but were rescued by adding back the cleavage product, (9-36)-NH2_further illustrating the distinct role of GLP-1 (9-36)-NH2 in promoting cell survival. This suggests future therapeutics would benefit by combining native GLP-1 along with its cleavage product, GLP-1 (9-36)-NH2. These findings demonstrate the novel effect of native GLP-1 and its cleavage-products on vessel wall health and provide new insights into creating more effective GLP-1 therapeutics for treatment of atherosclerosis and diabetes.

Investigating novel mechanisms of chemerin signalling in mature adipocytes

BACKGROUNDChemerin is a recently identified adipocyte‐secreted signalling molecule (adipokine) that plays local and systemic roles in the regulation of adipocyte differentiation, metabolism, and inflammation. Chemerin levels are increased in obese patients, however little is known regarding the signal transduction pathways coupled to chemerin signalling and how altered chemerin levels in obesity affect adipose function.OBJECTIVETo identify key signalling pathways and molecular targets influenced by chemerin signalling.RESULTSMicroarray analysis revealed that a number of genes with important roles in adipose tissue remodeling were up‐regulated following treatment of murine adipocytes with a neutralizing chemerin antibody. Functionally, this resulted in increased matrix metalloproteinase activity and recruitment of macrophages towards adipocyte‐conditioned medium. Treatment with a NFkB inhibitor was able to reverse these effects, suggesting a NFkB‐dependent mechanism.CONCLUSIONSChemerin mediates the expression of genes involved in adipose tissue remodeling and inflammation through a NFkB‐dependent pathway. This novel role for chemerin signalling likely has important effects on adipose tissue when chemerin levels are modified in obesity.Supported by CIHR, NSERC, and Killam Trusts.

1334 PROSTATE CANCER-ASSOCIATED FIBROBLASTS EXHIBIT DIFFERENCES IN GENE EXPRESSION PROFILES COMPARED TO NORMAL FIBROBLASTS IN THE SAME PATIENT

INTRODUCTION AND OBJECTIVES: There is strong evidence that the tumor microenvironment contributes to the normal prostate development as well as to proliferation, invasion and migration in prostatic carcinoma. Especially fibroblasts surrounding epithelial tumor cells seem to play a pivotal role during EMT and tumor invasion. Several strategies were undertaken to describe reliable biomarkers for cancer associated fibroblasts (CAF). Using fibroblasts from patients undergoing radical prostatectomy the expression profile of CAF was analysed using microarrays and compared to non-cancer associated fibroblasts of the same patient (NAF). To monitor the stability of gene expression profile during cell culture we quantified the expression levels of some CAFs specific genes like FAP, SMA, PDGFR and TGFbetween p1 to p7. METHODS: Tissue pieces from cancerous and cancer free areas of 7 prostates were cultivated for selection of CAF and NAF, respectively. Total RNA was isolated using RNeasy Kit (Qiagen) according to manufactures recommendation. For microarray expression analysis we used Illumina HT-12v4.0 Expression BeadChips. All primers and kits used for the qRT-PCR expression analysis of CAF-related genes during cell culture were purchased from Applied Biosystems. RESULTS: Using microarray analysis we found a significant overexpression of the following genes in fibroblasts associated to PCa tissue: MAP3K1 (a MAP kinase associated to stress and NFkB-dependent pathways), NBPF11 (neuroblastoma breakpoint family member 11), SCARB1 (regulates transport of HDL thus increasing the intracellular Cholesterol level). The expression of the plasminogen receptor S100A1 and SNAPC2 was decreased. Our qRT-PCR analysis offers a constant expression of SDF1, PDGFR , TGFand SMA during culture whereas the expression levels of the FAP gene decreased dramatically from p1 to p7. CONCLUSIONS: This is the first comprehensive expression analysis of NAF/CAF in PCa. Enhanced expression (MAP3K1, SCARB1) may influence cell movement and the level of cholesterol for androgen synthesis in fibroblasts. Since macrophage migration into tumor cells is controlled by S100A10 CAFs are able to control this process, too. Thus, our results provide strong evidence that these changes in gene expression in CAFs can contribute to functional alteration of adjacent prostate cancer cells. It is very important to note that during serial culture of fibroblast the expression profile of CAFrelated genes undergoes changes as a consequence to the particular in vitro culture.

TLR-4 and -6 agonists reverse apoptosis and promote maturation of simian virus 5-infected human dendritic cells through NFkB-dependent pathways

Infection of primary cultures of human immature monocyte-derived dendritic cells (moDC) with the paramyxovirus Simian Virus 5 (SV5) results in extensive cytopathic effect (CPE) and induction of apoptosis, but DC maturation pathways are not activated. In this study, we investigated the relationship between SV5-induced apoptosis and the lack of DC maturation. Reducing CPE and apoptosis in SV5-infected immature DC by the addition of a pancaspase inhibitor resulted in only low level expression of maturation markers CD40, CD80 and CD86, suggesting that SV5 infection either actively blocked maturation pathways or failed to provide sufficient signals to activate maturation. To distinguish between these hypotheses, SV5-infected immature DC were challenged with agonists that stimulate toll-like receptors (TLRs). Treatment with the TLR-4 agonist LPS or TLR-6 agonist FSL1 enhanced cell surface expression of CD40, CD80 and CD86 on SV5-infected cells to levels approaching that of mock-infected TLR-treated moDC, but treatment with agonists for TLR-2, -3, -5 or -8 had little effect. Addition of TLR-4 or -6 agonists to SV5-infected DC also dramatically reduced CPE and apoptosis, but the levels of viral protein and virus yield were not affected. Similarly, SV5-infected immature moDC were matured by treatment with IL-1β, and these mature infected cells also showed reduced CPE and apoptosis. In the presence of NFkB inhibitors, TLR-4 and -6 agonists did not promote maturation or reduce apoptosis of SV5-infected DC, indicating that maturation and cell survival were both dependent on signaling through NFkB-dependent pathways. Our results suggest a model whereby SV5 replication induces apoptosis in immature DC but fails to provide strong maturation signals, while activation of NFkB-dependent pathways by exogenous ligands can lead to moDC maturation and override SV5-induced cell death.

Vasoactive intestinal peptide, periodontal disease, and the innate immune response: an interview with Dr. John J. Taylor.

Vasoactive intestinal peptide, periodontal disease, and the innate immune response: an interview with Dr. John J. Taylor.

Heme oxygenase–1(HO-1)/carbon monoxide(CO) inhibit apoptotic signaling via a NFKB dependent pathway

Vallabhaneni, Raghuveer MD; Kim, Hoe Suk PhD; Billiar, Timothy MD; Zuckerbraun, Brian MD Author Information

Substance P (SP)—Induced interleukin-8 (IL-8) gene upregulation involves AP-1 and NFkB-dependent pathways

Substance P (SP)—Induced interleukin-8 (IL-8) gene upregulation involves AP-1 and NFkB-dependent pathways