Genistein Suppresses LPS-Induced Inflammatory Response through Inhibiting NF-κB following AMP Kinase Activation in RAW 264.7 Macrophages

Genistein, the major isoflavone in soybean, was recently reported to exert beneficial effects in metabolic disorders and inflammatory diseases. In the present study, we investigated the effects and mechanisms of a dietary concentration of genistein on the inflammatory response in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. Our results demonstrated that genistein effectively inhibited the LPS-induced overproduction of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6), as well as LPS-induced nuclear factor kappa B (NF-κB) activation. In addition, the data also showed that genistein prevented LPS-induced decrease in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. These effects were obviously attenuated by an AMPK inhibitor. Taken together, our results suggest that the dietary concentration of genistein is able to attenuate inflammatory responses via inhibition of NF-κB activation following AMPK stimulation. The data provide direct evidence for the potential application of low concentrations of genistein in the prevention and treatment of inflammatory diseases.     

Hyperuricemia Causes Pancreatic β-Cell Death and Dysfunction through NF-κB Signaling Pathway

Accumulating clinical evidence suggests that hyperuricemia is associated with an increased risk of type 2 diabetes. However, it is still unclear whether elevated levels of uric acid can cause direct injury of pancreatic β-cells. In this study, we examined the effects of uric acid on β-cell viability and function. Uric acid solution or normal saline was administered intraperitoneally to mice daily for 4 weeks. Uric acid-treated mice exhibited significantly impaired glucose tolerance and lower insulin levels in response to glucose challenge than did control mice. However, there were no significant differences in insulin sensitivity between the two groups. In comparison to the islets in control mice, the islets in the uric acid–treated mice were markedly smaller in size and contained less insulin. Treatment of β-cells in vitro with uric acid activated the NF-κB signaling pathway through IκBα phosphorylation, resulting in upregulated inducible nitric oxide synthase (iNOS) expression and excessive nitric oxide (NO) production. Uric acid treatment also increased apoptosis and downregulated Bcl-2 expression in Min6 cells. In addition, a reduction in insulin secretion under glucose challenge was observed in the uric acid–treated mouse islets. These deleterious effects of uric acid on pancreatic β-cells were attenuated by benzbromarone, an inhibitor of uric acid transporters, NOS inhibitor L-NMMA, and Bay 11–7082, an NF-κB inhibitor. Further investigation indicated that uric acid suppressed levels of MafA protein through enhancing its degradation. Collectively, our data suggested that an elevated level of uric acid causes β-cell injury via the NF-κB-iNOS-NO signaling axis.     

Involvement of MAPK/NF-κB Signaling in the Activation of the Cholinergic Anti-Inflammatory Pathway in Experimental Colitis by Chronic Vagus Nerve Stimulation

Background

Autonomic nervous system dysfunction is implicated in the etiopathogenesis of inflammatory bowel diseases (IBD). Therapies that increase cardiovagal activity, such as Mind-Body interventions, are currently confirmed to be effective in clinical trials in IBD. However, a poor understanding of pathophysiological mechanisms limits the popularization of therapies in clinical practice. The aim of the present study was to explore the mechanisms of these therapies against 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats using a chronic vagus nerve stimulation model in vivo, as well as the lipopolysaccharide (LPS)-induced inflammatory response in human epithelial colorectal adenocarcinoma cells (Caco-2) by acetylcholine in vitro.

Methods and Results

Colitis was induced in rats with rectal instillation of TNBS, and the effect of chronic VNS (0.25 mA, 20 Hz, 500 ms) on colonic inflammation was evaluated. Inflammatory responses were assessed by disease activity index (DAI), histological scores, myeloperoxidase (MPO) activity, inducible nitric oxide synthase (iNOS), TNF-α and IL-6 production. The expression of Mitogen-activated protein kinases (MAPK) family members, IκB-α, and nuclear NF-κB p65 were studied by immunoblotting. Heart rate variability (HRV) analysis was also applied to assess the sympathetic-vagal balance. DAI, histological scores, MPO activity, iNOS, TNF-α and IL-6 levels were significantly decreased by chronic VNS. Moreover, both VNS and acetylcholine reduced the phosphorylation of MAPKs and prevented the nuclear translocation of NF-κB p65. Methyllycaconitine (MLA) only reversed the inhibitory effect on p-ERK and intranuclear NF-κB p65 expression by ACh in vitro, no significant change was observed in the expression of p-p38 MAPK or p-JNK by MLA.

Conclusion

Vagal activity modification contributes to the beneficial effects of the cholinergic anti-inflammatory pathway in IBD-related inflamed colonic mucosa based on the activation of MAPKs and nuclear translocation of NF-κB. Our work may provide key pathophysiological mechanistic evidence for novel therapeutic strategies that increase the cardiovagal activity in IBD patients.     

Rutin Inhibits Neuroinflammation and Provides Neuroprotection in an Experimental Rat Model of Subarachnoid Hemorrhage,Possibly Through Suppressing the RAGE–NF-κB Inflammatory Signaling Pathway

Neurochemical Research - As is known to all, neuroinflammation plays a vital role in early brain injury pathogenesis following subarachnoid hemorrhage (SAH). It has been shown that rutin have a...     

PARP-1 Inhibitor,DPQ, Attenuates LPS-Induced Acute Lung Injury through Inhibiting NF-κB-Mediated Inflammatory Response

Acute lung injury (ALI) is characterized by overwhelming lung inflammation and anti-inflammation treatment is proposed to be a therapeutic strategy for ALI. Poly (ADP-ribose) polymerase-1 has been demonstrated to be involved in tissue inflammation and one of its inhibitors, 3, 4-Dihydro-5[4-(1-piperindinyl)butoxy]-1(2H)-isoquinoline (DPQ), exerts anti-inflammatory effect. However, it is still unclear whether the DPQ possesses the protective effect on ALI and what mechanisms are involved. In this study, we tested the effect of DPQ on the lung inflammation induced by lipopolysaccharide (LPS) challenge in mice. We found that 6 h-LPS challenge induced significant lung inflammation and vascular leakage in mice. Treatment with DPQ at the dose of 10 μg/kg markedly reduced the neutrophil infiltration, myeloperoxidase activity and up-regulation of pro-inflammatory mediators and cytokines. LPS-elevated vascular permeability was decreased by DPQ treatment, accompanied by the inhibition of apoptotic cell death in mice lungs. In addition, we isolated mice peritoneal macrophages and showed pretreatment with DPQ at 10 μM inhibited the production of cytokines in the macrophages following LPS stimulation. DPQ treatment also inhibited the phosphorylation and degradation of IκB-α, subsequently blocked the activation of nuclear factor (NF)-κB induced by LPS in vivo and in vitro. Taken together, our results show that DPQ treatment inhibits NF-κB signaling in macrophages and protects mice against ALI induced by LPS, suggesting inhibition of Poly (ADP-ribose) polymerase-1 may be a potential and effective approach to resolve inflammation for the treatment of ALI.     

Xanthotoxol from Saussurea obvallata Attenuates LPS-Induced RAW 264.7 Cells Inflammatory Responses through NF-κB Pathway

Russian Journal of Bioorganic Chemistry - Saussurea obvallata has been used as a medicinal herb to treat rheumatoid arthritis in Qinghai-Tibet Plateau. Xanthotoxol, one of the major ingredients of...     

Roles of PPARγ/NF-κB Signaling Pathway in the Pathogenesis of Intrahepatic Cholestasis of Pregnancy

Background

Intrahepatic cholestasis of pregnancy (ICP) is the most prevalent pregnancy specific liver disease. However, the pathogenesis and etiology of ICP is poorly understood.

Aim

To assess the expression of peroxisome proliferator-activated receptorγ (PPARγ) and nuclear factor kappa B (NF-κB) in placenta and HTR-8/SVneo cell, and evaluate the serum levels of cytokines, bile acids, hepatic function and lipids in control and ICP patients and the fetal outcome, in order to explore the role of PPARγ/NF-κB signaling pathway in the possible mechanism of ICP.

Methods

Clinical data of the pregnant women were collected and serum levels of cytokines, bile acids, hepatic function and lipids were measured. Expressions of PPARγ and NF-κB in placenta and HTR-8/SVneo cell were determined. The new-born information was collected to demonstrate the relationship between PPARγ/NF-κB signaling pathway and ICP.

Results

The serum levels of bile acids, hepatic function, triglycerides (TG), total cholesterol (TC), IL-6, IL-12 and TNF-α in ICP group were significantly increased (P<0.01), and serum level of IL-4 was significantly decreased (P<0.01). PPARγ and NF-κB staining were found in the membrane and cytoplasm of placental trophoblast cell. The expression of PPARγ and NF-κB were significantly higher in ICP group and taurocholate acid (TCA) treated HTR-8/SVneo cell (P<0.01). The new-born information in severe ICP group were significantly different as compared to that in control group (P<0.05), and part of information in mild ICP group were also difference to that in control group (P<0.05).

Conclusions

The higher expressions of PPARγ and NF-κB in ICP placenta and TCA treated HTR-8/SVneo cell, together with the abnormal serum levels of cytokines, might induced by the imbalance of inflammatory and immune reaction, and then disturb placental bile acid and serum lipids transportation, finally result in fatal cholestasis which probably be one of the mechanism of ICP.     

JLX001 Modulated the Inflammatory Reaction and Oxidative Stress in pMCAO Rats via Inhibiting the TLR2/4-NF-κB Signaling Pathway

Neurochemical Research - Inflammatory reactions and oxidative stress play critical roles in cerebral ischemic injuries. Microglia are activated after ischemic injury. Activated microglia produce...     

Induction of RANTES and CCR5 through NF-κB Activation via MAPK Pathway in Aged Rat Gingival Tissues

Chemokine and chemokine receptor expression in gingival tissues plays a central role in periodontal disease during aging. In the present study, we explored the modulation of chemokines and chemokine receptors expression in aging rat gingival tissues. In the 24-month-old (Old) rat gingival tissues, RANTES and CCR5 mRNA and protein levels were 2–4 fold increased over those of the 6-month-old (Young) rats. The Old rats had considerable enhancement of all three of the studied MAPK activities: extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK. These results suggest that age-related increases in RANTES and CCR5 expression are associated with increased IκBα, nuclear NF-κB, and MAPK activity in gingival tissues.     

Notch-1 Signaling Promotes the Malignant Features of Human Breast Cancer through NF-κB Activation

The aberrant activation of Notch-1 signaling pathway has been proven to be associated with the development and progression of cancers. However, the specific roles and the underlying mechanisms of Notch-1 signaling pathway on the malignant behaviors of breast cancer are poorly understood. In this study, using multiple cellular and molecular approaches, we demonstrated that activation of Notch-1 signaling pathway promoted the malignant behaviors of MDA-MB-231 cells such as increased cell proliferation, colony formation, adhesion, migration, and invasion, and inhibited apoptosis; whereas deactivation of this signaling pathway led to the reversal of the aforementioned malignant cellular behaviors. Furthermore, we found that activation of Notch-1 signaling pathway triggered the activation of NF-κB signaling pathway and up-regulated the expression of NF-κB target genes including MMP-2/-9, VEGF, Survivin, Bcl-xL, and Cyclin D1. These results suggest that Notch-1 signaling pathway play important roles in promoting the malignant phenotype of breast cancer, which may be mediated partly through the activation of NF-κB signaling pathway. Our results further suggest that targeting Notch-1 signaling pathway may become a newer approach to halt the progression of breast cancer.     

Gelam Honey Attenuates Carrageenan-Induced Rat Paw Inflammation via NF-κB Pathway

The activation of nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of a number of inflammatory diseases. In this study, we investigated the anti-inflammatory mechanism of Gelam honey in inflammation induced rats via NF-κB signalling pathway. Rats paw edema was induced by subplantar injection of 1% carrageenan into the right hind paw. Rats were pre-treated with Gelam honey at different doses (1 or 2 g/kg, p.o.) and NSAID Indomethacin (10 mg/kg, p.o.), in two time points (1 and 7 days). Our results showed that Gelam honey at both concentrations suppressed the gene expressions of NF-κB (p65 & p50) and IκBα in inflamed rats paw tissues. In addition, Gelam honey inhibited the nuclear translocation and activation of NF-κB and decreased the cytosolic degradation of IκBα dose dependently in inflamed rats paw tissues. The immunohistochemical expressions of pro-inflammatory mediators COX-2 and TNF-α were also decreased in inflamed rats paw tissues when treated with Gelam honey. The results of our findings suggest that Gelam honey exhibits its inhibitory effects by attenuating NF-κB translocation to the nucleus and inhibiting IκBα degradation, with subsequent decrease of inflammatory mediators COX-2 and TNF-α.     

Brap2 Regulates Temporal Control of NF-κB Localization Mediated by Inflammatory Response

Nuclear factor-kappaB (NF-κB) is critical for the expression of multiple genes involved in inflammatory responses and cellular survival. NF-κB is normally sequestered in the cytoplasm through interaction with an inhibitor of NF-κB (IκB), but inflammatory stimulation induces proteasomal degradation of IκB, followed by NF-κB nuclear translocation. The degradation of IκB is mediated by a SCF (Skp1-Cullin1-F-box protein)-type ubiquitin ligase complex that is post-translationaly modified by a ubiquitin-like molecule Nedd8. In this study, we report that BRCA1-associated protein 2 (Brap2) is a novel Nedd8-binding protein that interacts with SCF complex, and is involved in NF-κB translocation following TNF-α stimulation. We also found a putative neddylation site in Brap2 associated with NF-κB activity. Our findings suggest that Brap2 is a novel modulator that associates with SCF complex and controls TNF-α-induced NF-κB nuclear translocation.     

The Overexpression of TGF-β and CCN2 in Intrauterine Adhesions Involves the NF-κB Signaling Pathway

Intrauterine adhesions (IUA) are a significant cause of menstrual disturbance and infertility, but their pathogenesis still remains unclear. Here, we investigated the expression of TGF-β and CCN2 in IUA endometrial tissue by immunohistochemistry, western blotting and qRT-PCR assays, and found the expression of TGF-β and CCN2 in the endometrial tissue of IUA was significantly increased compared to normal endometrium and uterine septum (P<0.01), suggesting that TGF-β and CCN2 may play an important role in the formation of IUA. Moreover, the activity of the NF-κB signaling pathway in endometrial tissue of IUA was also significantly enhanced compared to normal endometrial and uterine septum (P<0.01) and positively correlated with the expression of TGF-β and CCN2, which suggested that TGF-β and CCN2 expression may be involved in the NF-κB signaling pathway. Blocking the NF-κB signaling pathway using SN50 resulted in the reduced expression of TGF-β in RL95-2 cells, which confirmed the association of the NF-κB signaling pathway and TGF-β in endometrial cells. Additionally, the expression of TGF-β and CCN2 was associated with IUA recurrence, which provides a potential prognostic indictor for IUA. Together, these results demonstrated that TGF-β and CCN2 play an important role in IUA formation, whose mechanism was associated with the activation of the NF-κB signaling pathway.