Nuclear Factor-Kappa-B Mediates the Advanced Glycation End Product-Induced Repression of Slc2a4 Gene Expression in 3T3-L1 Adipocytes.

Advanced glycated end products (AGEs) are cytotoxic compounds that are mainly increased in diabetes mellitus (DM), kidney failure, inflammation, and in response to the ingestion of AGE-rich diets. AGEs can also impair glycemic homeostasis by decreasing the expression of the Slc2a4 (solute carrier family 2 member 4) gene and its GLUT4 (solute carrier family 2, facilitated glucose transporter member 4) protein in muscle. However, the mechanisms underlying AGE's effect on adipocytes have not been demonstrated yet. This study investigated the effects of AGEs upon Slc2a4/GLUT4 expression in 3T3-L1 adipocytes, as well as the potential role of NFKB (nuclear factor NF-kappa-B) activity in the effects observed. Adipocytes were cultured in the presence of control albumin (CA) or advanced glycated albumin (GA) at concentrations of 0.4, 3.6, and 5.4 mg/mL for 24 h or 72 h. Slc2a4, Rela, and Nfkb1mRNAs were measured by RT-qPCR, GLUT4, IKKA/B, and p50/p65 NFKB subunits using Western blotting, and p50/p65 binding into the Slc2a4 promoter was analyzed by chromatin immunoprecipitation (ChIP) assay. GA at 0.4 mg/mL increased Slc2a4/GLUT4 expression after 24 h and 72 h (from 50% to 100%), but at 5.4 mg/mL, Slc2a4/GLUT4 expression decreased at 72 h (by 50%). Rela and Nfkb1 expression increased after 24 h at all concentrations, but this effect was not observed at 72 h. Furthermore, 5.4 mg/mL of GA increased the p50/p65 nuclear content and binding into Slc2a4 at 72 h. In summary, this study reveals AGE-induced and NFKB-mediated repression of Slc2a4/GLUT4 expression. This can compromise the adipocyte glucose utilization, contributing not only to the worsening of glycemic control in DM subjects but also the impairment of glycemic homeostasis in non-DM subjects under the high intake of AGE-rich foods.

A hepatocyte-specific transcriptional program driven by Rela and Stat3 exacerbates experimental colitis in mice by modulating bile synthesis.

Hepatic factors secreted by the liver promote homeostasis and are pivotal for maintaining the liver-gut axis. Bile acid metabolism is one such example wherein, bile acid synthesis occurs in the liver and its biotransformation happens in the intestine. Dysfunctional interactions between the liver and the intestine stimulate varied pathological outcomes through its bidirectional portal communication. Indeed, aberrant bile acid metabolism has been reported in inflammatory bowel disease (IBD). However, the molecular mechanisms underlying these crosstalks that perpetuate intestinal permeability and inflammation remain obscure. Here, we identify a novel hepatic gene program regulated by Rela and Stat3 that accentuates the inflammation in an acute experimental colitis model. Hepatocyte-specific ablation of Rela and Stat3 reduces the levels of primary bile acids in both the liver and the gut and shows a restricted colitogenic phenotype. On supplementation of chenodeoxycholic acid (CDCA), knock-out mice exhibit enhanced colitis-induced alterations. This study provides persuasive evidence for the development of multi-organ strategies for treating IBD and identifies a hepatocyte-specific Rela-Stat3 network as a promising therapeutic target.

The effects of mineral trioxide aggregate and second-generation autologous growth factor on pulpotomy via TNF-α and NF-kß/p65 pathways.

This study aims to investigate the effect of Mineral Trioxide Aggregate (MTA), a bioactive endodontic cement, and Concentrated Growth Factor (CGF), a second-generation autologous growth factor, on pulpotomy-induced pulp inflammation. The study utilized the maxillary anterior central teeth of thirty-six young male Sprague Dawley rats. Forty-eight teeth were randomly assigned to two groups (12 rats/group; 24 teeth/group) based on the capping material (MTA or CGF). Subsequently, two subgroups (MTAG and CGFG) were formed per group (12 teeth/group) based on the time following pulpotomy (2-weeks and 4-weeks). The central teeth of the 12 animals assigned to the control group (CG) were not manipulated in any way, both in the 2-week group and in the 4-week group. Tissue samples extracted from rats at the end of the experiment were stained with H&E for histopathological analysis. For immunohistochemical analysis, primary antibodies for TNF-α and NF-kß/65 were incubated. Data obtained from semi-quantitative analysis were assessed for normal distribution using Skewness-Kurtosis values, Q-Q plot, Levene's test, and the Shapiro-Wilk test on statistical software. A P value < 0.05 was considered significant. When compared with the control group, both MTAG and CGFG showed increased edematous and inflammatory areas. In MTAG, edematous and inflammatory areas decreased significantly from the 2nd week (2(2-2), 2(1-2)) to the 4th week (1(1-1), 1(0-1)), while in CGFG, edematous areas decreased (2(2-3), 1.5(1-2)), and inflammatory areas increased significantly (2(2-3), 3(2-2.5)). When compared with the control group, TNF-α and NF-kß/p65 positivity were higher in both MTAG and CGFG. In MTAG, TNF-α [2(1.5-2)] and NF-kß/p65 [1.5(1-2)] positivity decreased significantly from the 2nd week to the 4th week [TNF-α: 1(1-1), NF-kß/p65: 1(1-2)], while no significant change was observed in CGFG. In conclusion, this study revealed a reduction in cells showing TNF-α and NF-kß/p65 positivity in the MTA treatment group compared to the CGF group. Although MTA demonstrated more favorable results than CGF in mitigating pulpal inflammation within the scope of this study, further experimental and clinical investigations are warranted to obtain comprehensive data regarding CGF.

Silicone dressing combined with topical oxygen therapy alleviates incontinence-associated dermatitis via NF-κB p65/STAT1 signaling pathway.

BACKGROUND: Incontinence-associated dermatitis (IAD) is a tough problem in clinical settings, not only increasing the risk of complications like catheter-related urinary tract infections and pressure ulcers in elderly and critically ill patients, but also prolonging hospital stays, raising hospital costs, and possibly leading to medical disputes. This study is aimed to evaluate the therapeutic effect of silicone dressing combined with topical oxygen therapy on IAD in a rat model. METHODS: An IAD rat model induced by synthetic urine with trypsin was established. Hematoxylin & eosin staining was carried out to examine skin histology. Using immunofluorescence, the microvessel density in the affected skin tissues was determined. ELISA was performed to measure the concentrations of inflammatory cytokines and angiogenic factors in serum. The mRNA expression of EGF, PDGF, and VEGF was detected via qRT-PCR. Western blotting was employed to determine NF-κB p65/STAT1 pathway-related protein levels. RESULTS: Compared to single therapy, silicone dressing combined with topical oxygen therapy could significantly reduce the severity of IAD, improve skin histology, inhibit inflammation, and promote angiogenesis in IAD rat models. Additionally, the results showed that relatively speaking, the combined therapy suppressed the NF-κB p65/STAT1 signaling pathway more effectively. CONCLUSION: These findings indicated that silicone dressing combined with topical oxygen therapy can alleviate IAD through promoting wound healing and inhibiting inflammation via NF-κB p65/STAT1 signaling pathway in a rat model, which provided a theoretical basis for the prevention and treatment of IAD in clinic.

Inhibition of α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid Receptors Ameliorates Atrial Inflammation and Vulnerability to Atrial Fibrillation in Rats with Anxiety Disorders.

ABSTRACT: Previous studies have found that anxiety disorders may increase the incidence of atrial fibrillation (AF). More and more studies have shown that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are involved in the occurrence and development of cardiovascular diseases. However, the role of AMPARs in AF associated with anxiety disorder remains unclear. The aim of this study was to investigate the effect of AMPARs on AF susceptibility in rats with anxiety disorder and its possible mechanism. The anxiety disorder rat model was established by unpredictable empty bottle stimulation and was treated with AMPARs agonist and antagonist. Our results showed that AMPARs antagonist treatment significantly reduced sympathetic activity, improved heart rate variability, shortened action potential duration, prolonged effective refractory period, reduced AF induction rate, and improved cardiac electrical remodeling and the expression of inflammatory factors. In addition, inhibition of AMPARs reduced the phosphorylation of IκBα and p65. Our experimental results suggest that inhibition of AMPARs can reduce autonomic remodeling, improve atrial electrical remodeling, and suppress myocardial inflammation, which provides a potential therapeutic strategy for the treatment of AF associated with anxiety disorder.

Effects of tanshinone IIA on endothelial cell dysfunction in uremic condition.

An arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis in uremic patients, yet its dysfunction poses a significant clinical challenge. Venous stenosis, primarily caused by venous neointimal hyperplasia, is a key factor in the failure of vascular access. During vascular access dysfunction, endothelial cells (ECs) transform mechanical stimuli into intracellular signals and interact with vascular smooth muscle cells. Tanshinone IIA, an important compound derived from Salvia miltiorrhiza, has been widely used to treat cardiovascular diseases. However, its role in modulating ECs under uremic conditions remains incompletely understood. In this research, ECs were exposed to sodium tanshinone IIA sulfonate (STS) and subjected to shear stress and uremic conditions. The results indicate that STS can reduce the suppressive effects on the expression of NF-κB p65, JNK and Collagen I in uremia-induced ECs. Moreover, the downregulation of NF-κB p65, JNK and Collagen I can be enhanced through the inhibition of ERK1/2 and the upregulation of Caveolin-1. These findings suggest that tanshinone IIA may improve EC function under uremic conditions by targeting the Caveolin-1/ERK1/2 pathway, presenting tanshinone IIA as a potential therapeutic agent against AVF immaturity caused by EC dysfunction.

YAP represses the TEAD-NF-κB complex and inhibits the growth of clear cell renal cell carcinoma.

The Hippo pathway is generally understood to inhibit tumor growth by phosphorylating the transcriptional cofactor YAP to sequester it to the cytoplasm and reduce the formation of YAP-TEAD transcriptional complexes. Aberrant activation of YAP occurs in various cancers. However, we found a tumor-suppressive function of YAP in clear cell renal cell carcinoma (ccRCC). Using cell cultures, xenografts, and patient-derived explant models, we found that the inhibition of upstream Hippo-pathway kinases MST1 and MST2 or expression of a constitutively active YAP mutant impeded ccRCC proliferation and decreased gene expression mediated by the transcription factor NF-κB. Mechanistically, the NF-κB subunit p65 bound to the transcriptional cofactor TEAD to facilitate NF-κB-target gene expression that promoted cell proliferation. However, by competing for TEAD, YAP disrupted its interaction with NF-κB and prompted the dissociation of p65 from target gene promoters, thereby inhibiting NF-κB transcriptional programs. This cross-talk between the Hippo and NF-κB pathways in ccRCC suggests that targeting the Hippo-YAP axis in an atypical manner-that is, by activating YAP-may be a strategy for slowing tumor growth in patients.

The relationship between Nuclear Factor-Kappa B and Inhibitor-Kappa B parameters with clinical course in COVID-19 patients.

BACKGROUND: We aimed to investigate the serum Nuclear Factor Kappa B (NF-κB) p105, NF-κB p65 and Inhibitor Kappa B Alpha (IκBα) levels in patients with mild/moderate Coronavirus Disease 2019 (COVID-19) and their association with the course of the disease. MATERIALS AND METHODS: Blood was drawn from 35 COVID-19 patients who applied to the Department of Emergency Medicine of Istanbul University-Cerrahpasa at the time of diagnosis and from 35 healthy individuals. The patients were evaluated to have mild/moderate degree of disease according to National Early Warning Score 2 (NEWS2) scoring and computed tomography (CT) findings. The markers were studied in the obtained serum samples, using enzyme-linked immunoassay (ELISA). Receiver Operating Characteristic (ROC) analysis was performed. Statistical significance was evaluated to be p < 0.05. RESULTS: NF-κB p105 levels were significantly higher in the COVID-19 group compared to the control group. C-reactive protein (CRP), D-dimer, ferritin levels of the patients were significantly higher (p < 0.001) compared to the control group, while the lymphocyte count was found lower (p = 0.001). IκBα and NF-κB p65 levels are similar in both groups. Threshold value for NF-κB p105 was above 0.78 ng/mL, sensitivity was 71.4% and specificity was 97.1% (p < 0.05). NF-κB p105 levels at the time of diagnosis of the patients who required supplemental oxygen (O2), were significantly higher (p < 0.01). CONCLUSIONS: The rise in serum NF-κB p105 levels during the early stages of infection holds diagnostic value. Besides its relation with severity might have a prognostic feature to foresee the requirement for supplemental O2 that occurs during hospitalization.

[Inhibitory effect of 5-hydroxy-6,7-dimethoxyflavone on H1N1 influenza virus-induced ferroptosis and inflammation in A549 cells and its possible mechanisms].

OBJECTIVE: To investigate the protective effect of 5-hydroxy-6,7-dimethoxyflavone (5-HDF), a compound extracted from Elsholtzia blanda Benth., against lung injury induced by H1N1 influenza virus and explore its possible mechanism of action. METHODS: 5-HDF was extracted from Elsholtzia blanda Benth. using ethanol reflux extraction and silica gel chromatography and characterized using NMR and MS analyses. In an A549 cell model of H1N1 influenza virus infection (MOI=0.1), the cytotoxicity of 5-HDF was assessed using MTT assay, and its effect on TRAIL and IL-8 expressions was examined using flow cytometry; Western blotting was used to detect the expression levels of inflammatory, apoptosis, and ferroptosis-related proteins. In a mouse model of H1N1 influenza virus infection established by nasal instillation of 50 µL H1N1 virus at the median lethal dose, the effects of 30 and 60 mg/kg 5-HDF by gavage on body weight, lung index, gross lung anatomy and lung histopathology were observed. RESULTS: 5-HDF exhibited no significant cytotoxicity in A549 cells within the concentration range of 0-200 µg/mL. In H1N1-infected A549 cells, treatment with 5-HDF effectively inhibited the activation of phospho-p38 MAPK and phospho-NF-κB p65, lowered the expressions of IL-8, enhanced the expression of anti-ferroptosis proteins (SLC7A11 and GPX4), and inhibited the expressions of apoptosis markers PARP and caspase-3 and the apoptotic factor TRAIL. In H1N1-infected mice, treatment with 5-HDF for 7 days significantly suppressed body weight loss and increment of lung index and obviously alleviated lung tissue pathologies. CONCLUSION: 5-HDF offers protection against H1N1 influenza virus infection in mice possibly by suppressing H1N1-induced ferroptosis, inflammatory responses, and apoptosis via upregulating SLC7A11 and GPX4, inhibiting the activation of phospho-NF-κB p65 and phospho-p38 MAPK, and decreasing the expression of cleaved caspase3 and cleaved PARP.

Mecp2 promotes the anti-inflammatory effect of alpinetin via epigenetic modification crosstalk.

In recent years, inflammatory disorders have emerged as a significant concern for human health. Through ongoing research on anti-inflammatory agents, alpinetin has shown promising anti-inflammatory properties, including involvement in epigenetic modification pathways. As a crucial regulator of epigenetic modifications, Mecp2 may play a role in modulating the epigenetic effects of alpinetin, potentially impacting its anti-inflammatory properties. To test this hypothesis, two key components, p65 (a member of NF-KB family) and p300 (a type of co-activator), were screened by the expression profiling microarray, which exhibited a strong correlation with the intensity of LPS stimulation in mouse macrophages. Meanwhile, alpinetin demonstrates the anti-inflammatory properties through its ability to disrupt the synthesis of p65 and its interaction with promoters of inflammatory genes, yet it did not exhibit similar effects on p300. Additionally, Mecp2 can inhibit the binding of p300 by attaching to the methylated inflammatory gene promoter induced by alpinetin, leading to obstacles in promoter acetylation and subsequently impacting the binding of p65, ultimately enhancing the anti-inflammatory capabilities of alpinetin. Similarly, in a sepsis mouse model, it was observed that homozygotes overexpressing Mecp2 showed a greater reduction in organ damage and improved survival rates compared to heterozygotes when administered by alpinetin. However, blocking the expression of DNA methyltransferase 3A (DNMT3A) resulted in the loss of Mecp2's anti-inflammatory assistance. In conclusion, Mecp2 may augment the anti-inflammatory effects of alpinetin through epigenetic 'crosstalk', highlighting the potential efficacy of a combined therapeutic strategy involving Mecp2 and alpinetin for anti-inflammatory intervention.

Morin Regulates M1/M2 Microglial Polarization via NF-κB p65 to Alleviate Vincristine-Induced Neuropathic Pain.

Background: Morin can alleviate vincristine-induced neuropathic pain via inhibiting neuroinflammation. Microglial cells play an important role in initiating and maintenance of pain and neuroinflammation. It remains unclear whether morin exerts antinociceptive properties through the regulation of microglial cells. This study aimed to elucidate the mechanisms of morin against neuropathic pain focusing on microglial cells. Methods: The thermal withdrawal latency and mechanical withdrawal threshold were used as measures of pain behaviours. Histological abnormalities of the sciatic nerve were observed with transmission electron microscopy. The sciatic functional index and the sciatic nerve conduction velocity were used as measures of the functional deficits of the sciatic nerve. Inflammatory factors were detected using ELISA. The expression of M1/M2 polarization markers of microglia and nuclear factor κB (NF-κB) p65 were measured by immunofluorescence, real-time quantitative PCR and Western blotting. Results: Morin alleviated vincristine-induced abnormal pain, sciatic nerve injury, and neuroinflammatory response in rats. Furthermore, morin decreased the expression of NF-κB P65 and M1 activation markers, increased the expression of M2 activation markers. Additionally, phorbol 12-myristate 13-acetate reversed the effects of morin on microglial polarization, the production of inflammatory factors and neuropathic pain, while ammonium pyrrolidine dithiocarbamate showed the opposite effects. Conclusion: Our results demonstrate that morin inhibits neuroinflammation to alleviate vincristine-induced neuropathic pain via inhibiting the NF-κB signalling pathway to regulate M1/M2 microglial polarization.

Electroacupuncture Alleviates Parkinson's Disease by Promoting METTL9-Catalyzed Histidine Methylation of Nuclear Factor-κВ.

This study aimed to investigate the effects of electroacupuncture (EA) treatment on Parkinson's disease (PD). 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration was used establish PD mice model. The number of neurons is determined by TH staining. mRNA expression is detected by RT-qPCR. Protein expression was detected by Western blot. Gene expression is determined by immunofluorescence and immunohistochemistry. The functions of neurons are determined by TUNEL and flow cytometry assay. The binding sites of nuclear factor kappa B (NF-κB) RELA on the promoter of NLRP3 are predicted by JASPAR and verified by luciferase and ChIP assays. The results showed that EA treatment improves motor dysfunction in patients with PD. In vivo assays show that MPTP administration induces the loss of neurons in mice, which is restored by EA treatment. Moreover, EA treatment alleviates motor deficits in MPTP-induced PD mice. EA treatment also inhibits the enrichment of pro-inflammatory cytokines and lactodehydrogenase and suppresses neuronal pyroptosis. EA treatment increases the expression of METTL9. However, METTL9 deficiency dampens the effects of EA treatment and induces neuronal pyroptosis. Additionally, METTL9 promotes histidine methylation of NF-κB RELA, resulting the inhibition of epigenetic transcription of NLRP3. EA treatment restores neuronal function and improves motor dysfunction via promoting METTL9 histidine methylation of NF-κB/ NLRP3 signaling.

Structural and biochemical analyses of the nuclear IκBζ protein in complex with the NF-κB p50 homodimer.

As part of the efforts to understand nuclear IκB function in NF-κB-dependent gene expression, we report an X-ray crystal structure of the IκBζ ankyrin repeat domain in complex with the dimerization domain of the NF-κB p50 homodimer. IκBζ possesses an N-terminal α helix that conveys domain folding stability. Affinity and specificity of the complex depend on a small portion of p50 at the nuclear localization signal. The model suggests that only one p50 subunit supports binding with IκBζ, and biochemical experiments confirm that IκBζ associates with DNA-bound NF-κB p50:RelA heterodimers. Comparisons of IκBζ:p50 and p50:κB DNA complex crystallographic models indicate that structural rearrangement is necessary for ternary complex formation of IκBζ and p50 with DNA.

Diosgenin Reduces Acute Kidney Injury and Ameliorates the Progression to Chronic Kidney Disease by Modifying the NOX4/p65 Signaling Pathways.

Acute kidney injury (AKI), if not well controlled, may progress to chronic kidney disease (CKD). Diosgenin is a natural phytosteroid sapogenin from plants. This study aimed to investigate the mechanistic effects of diosgenin on AKI and AKI related development of CKD. The mouse model of ischemia/reperfusion (I/R)-induced AKI was used, and its progressive changes were followed. Human renal proximal tubular epithelial cells were used, and hypoxia stimulation was applied to mimic the in vivo I/R. Diosgenin, given after renal injury, preserved kidney function, as evidenced by a reduction in serum levels of BUN, creatinine, and UACR in both acute and chronic phases of AKI. Diosgenin alleviated I/R-induced tubular injury and prevented macrophage infiltration and renal fibrosis in AKI mice. Furthermore, diosgenin also mitigated the development of CKD from AKI with reduced renal expression of inflammatory, fibrotic, and epithelial-mesenchymal transition markers. In human renal tubular epithelial cells, diosgenin downregulated the hypoxia-induced oxidative stress and cellular damages that were dependent on the NOX4/p65 signaling pathways. Taken together, diosgenin treatment reduced I/R-induced AKI and ameliorated the progression to CKD from AKI probably by modifying the NOX4/p65 signaling pathways.

Elevated WTAP promotes hyperinflammation by increasing m6A modification in inflammatory disease models.

Emerging evidence has linked the dysregulation of N6-methyladenosine (m6A) modification to inflammation and inflammatory diseases, but the underlying mechanism still needs investigation. Here, we found that high levels of m6A modification in a variety of hyperinflammatory states are p65-dependent because Wilms tumor 1-associated protein (WTAP), a key component of the "writer" complex, is transcriptionally regulated by p65, and its overexpression can lead to increased levels of m6A modification. Mechanistically, upregulated WTAP is more prone to phase separation to facilitate the aggregation of the writer complex to nuclear speckles and the deposition of m6A marks on transcriptionally active inflammatory transcripts, thereby accelerating the proinflammatory response. Further, a myeloid deficiency in WTAP attenuates the severity of LPS-induced sepsis and DSS-induced IBD. Thus, the proinflammatory effect of WTAP is a general risk-increasing mechanism, and interrupting the assembly of the m6A writer complex to reduce the global m6A levels by targeting the phase separation of WTAP may be a potential and promising therapeutic strategy for alleviating hyperinflammation.

An in vitro model of acute horizontal basal cell activation reveals gene regulatory networks underlying the nascent activation phase.

While horizontal basal cells (HBCs) make minor contributions to olfactory epithelium (OE) regeneration during homeostatic conditions, they possess a potent, latent capacity to activate and subsequently regenerate the OE following severe injury. Activation requires, and is mediated by, the downregulation of the transcription factor (TF) TP63. In this paper, we describe the cellular processes that drive the nascent stages of HBC activation. The compound phorbol 12-myristate 13-acetate (PMA) induces a rapid loss in TP63 protein and rapid enrichment of HOPX and the nuclear translocation of RELA, previously identified as components of HBC activation. Using bulk RNA sequencing (RNA-seq), we find that PMA-treated HBCs pass through various stages of activation identifiable by transcriptional regulatory signatures that mimic stages identified in vivo. These temporal stages are associated with varying degrees of engraftment and differentiation potential in transplantation assays. Together, these data show that our in vitro HBC activation system models physiologically relevant features of in vivo HBC activation and identifies new candidates for mechanistic testing.

IQGAP1 domesticates macrophages to favor mycobacteria survival via modulating NF-κB signal and augmenting VEGF secretion.

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), still ranks among the leading causes of annual human death by infectious disease. Mtb has developed several strategies to survive for years at a time within the host despite the presence of a robust immune response, including manipulating the progression of the inflammatory response and forming granulomatous lesions. Here we demonstrate that IQGAP1, a highly conserved scaffolding protein, compartmentalizes and coordinates multiple signaling pathways in macrophages infected with Mycobacterium marinum (Mm or M.marinum), the closest relative of Mtb. Upregulated IQGAP1 ultimately suppresses TNF-α production by repressing the MKK3 signal and reducing NF-κBp65 translocation, deactivating the p38MAPK pathway. Accordingly, IQGAP1 silencing and overexpression significantly alter p38MAPK activity by modulating the production of phosphorylated MKK3 during mycobacterial infection. Pharmacological inhibition of IQGAP1-associated microtubule assembly not only alleviates tissue damage caused by M.marinum infection but also significantly decreases the production of VEGF-a critical player for granuloma-associated angiogenesis during pathogenic mycobacterial infection. Similarly, IQGAP1 silencing in Mm-infected macrophages diminishes VEGF production, while IQGAP1 overexpression upregulates VEGF. Our data indicate that mycobacteria induce IQGAP1 to hijack NF-κBp65 activation, preventing the expression of proinflammatory cytokines as well as promoting VEGF production during infection and granuloma formation. Thus, therapies targeting host IQGAP1 may be a promising strategy for treating tuberculosis, particularly in drug-resistant diseases.

Birch pollen-induced signatures in dendritic cells are maintained upon additional cytomegalovirus exposure.

During the birch pollen season an enhanced incidence of virus infections is noticed, raising the question whether pollen can affect anti-viral responses independent of allergic reactions. We previously showed that birch pollen-treatment of monocyte-derived dendritic cells (moDC) enhances human cytomegalovirus (HCMV) infection. Here we addressed how in moDC the relatively weak pollen response can affect the comparably strong response to HCMV. To this end, moDC were stimulated with aqueous birch pollen extract (APE), HCMV, and APE with HCMV, and transcriptomic signatures were determined after 6 and 24 h of incubation. Infection was monitored upon exposure of moDC to GFP expressing HCMV by flow cytometric analysis of GFP expressing cells. Principle component analysis of RNA sequencing data revealed close clustering of mock and APE treated moDC, whereas HCMV as well as APE with HCMV treated moDC clustered separately after 6 and 24 h of incubation, respectively. Communally induced genes were detected in APE, HCMV and APE with HCMV treated moDC. In APE with HCMV treated moDC, the comparably weak APE induced signatures were maintained after HCMV exposure. In particular, NF-κB/RELA and PI3K/AKT/MAPK signaling were altered upon APE with HCMV exposure. Earlier, we discovered that NF-κB inhibition alleviated APE induced enhancement of HCMV infection. Here we additionally found that impairment of PI3K signaling reduced HCMV infection in HCMV and APE with HCMV treated moDC. APE treated moDC that were exposed to HCMV show a unique host gene signature, which to a large extent is regulated by NF-κB activation and PI3K/AKT/MAPK signaling.

Inducible gene expression of IκB-kinase ε is dependent on nuclear factor-κB in human pulmonary epithelial cells.

While IκB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its up-regulation by inflammatory cytokines remains under-explored. Since airway epithelial cells respond to airborne insults and potentiate inflammation, IKKε expression was characterized in pulmonary epithelial cell lines (A549, BEAS-2B) and primary human bronchial epithelial cells grown as submersion or differentiated air-liquid interface cultures. IKKε expression was up-regulated by the pro-inflammatory cytokines, interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNFα). Thus, mechanistic interrogations in A549 cells were used to demonstrate the NF-κB dependence of cytokine-induced IKKε. Furthermore, chromatin immunoprecipitation in A549 and BEAS-2B cells revealed robust recruitment of the NF-κB subunit, p65, to one 5' and two intronic regions within the IKKε locus (IKBKE). In addition, IL-1ß and TNFα induced strong RNA polymerase 2 recruitment to the 5' region, the first intron, and the transcription start site. Stable transfection of the p65-binding regions into A549 cells revealed IL-1ß- and TNFα-inducible reporter activity that required NF-κB, but was not repressed by glucocorticoid. While critical NF-κB motifs were identified in the 5' and downstream intronic regions, the first intronic region did not contain functional NF-κB motifs. Thus, IL-1ß- and TNFα-induced IKKε expression involves three NF-κB-binding regions, containing multiple functional NF-κB motifs, and potentially other mechanisms of p65 binding through non-classical NF-κB binding motifs. By enhancing IKKε expression, IL-1ß may prime, or potentiate, responses to alternative stimuli, as modelled by IKKε phosphorylation induced by phorbol 12-myristate 13-acetate. However, since IKKε expression was only partially repressed by glucocorticoid, IKKε-dependent responses could contribute to glucocorticoid-resistant disease.

Selective regulation of a defined subset of inflammatory and immunoregulatory genes by an NF-κB p50-IκBζ pathway.

The five NF-κB family members and three nuclear IκB proteins play important biological roles, but the mechanisms by which distinct members of these protein families contribute to selective gene transcription remain poorly understood, especially at a genome-wide scale. Using nascent transcript RNA-seq, we observed considerable overlap between p50-dependent and IκBζ-dependent genes in Toll-like receptor 4 (TLR4)-activated macrophages. Key immunoregulatory genes, including Il6, Il1b, Nos2, Lcn2, and Batf, are among the p50-IκBζ-codependent genes. IκBζ-bound genomic sites are occupied at earlier time points by NF-κB dimers. However, p50-IκBζ codependence does not coincide with preferential binding of either p50 or IκBζ, as RelA co-occupies hundreds of genomic sites with the two proteins. A common feature of p50-IκBζ-codependent genes is a nearby p50/RelA/IκBζ-cobound site exhibiting p50-dependent binding of both RelA and IκBζ. This and other results suggest that IκBζ acts in concert with RelA:p50 heterodimers. Notably, p50-IκBζ-codependent genes comprise a high percentage of genes exhibiting the greatest differential expression between TLR4-stimulated and tumor necrosis factor receptor (TNFR)-stimulated macrophages. Thus, our genome-centric analysis reveals a defined p50-IκBζ pathway that selectively activates a set of key immunoregulatory genes and serves as an important contributor to differential TNFR and TLR4 responses.