NF‐κB activation mediates LPS‐or zymosan‐induced hypotension and inflammation reversed by BAY61‐3606, a selective Syk inhibitor,in rat models of septic and non‐septic shock

We have previously demonstrated that the activation of the spleen tyrosine kinase (Syk)/inhibitory‐κB (IκB)‐α/nuclear factor‐κB (NF‐κB) p65 signalling pathway contributes to hypotension and inflammatory response in a rat models of zymosan (ZYM)‐induced non‐septic shock. The purpose of this study was to further examine the possible mechanism underlying the effect of inhibition of Syk by BAY61‐3606 via NF‐κB activity at the level of nuclear translocation regarding the production of vasodilator and proinflammatory mediators in lipopolysaccharide (LPS) (septic)‐ and ZYM (non‐septic)‐induced shock. Administration of LPS (10 mg/kg, ip) or ZYM (500 mg/kg, ip) to male Wistar rats decreased mean arterial pressure and increased heart rate that was associated with an increase in the activities of cyclooxygenase and nitric oxide synthase, tumour necrosis factor‐α, and interleukin‐8 levels, and NF‐κB activation and nuclear translocation in sera and/or cardiovascular and renal tissues. BAY61‐3606 (3 mg/kg, ip), the selective Syk inhibitor, given 1 hour after LPS‐ or ZYM injection reversed all the above‐mentioned effects. These results suggest that Syk contributes to the LPS‐ or ZYM‐induced hypotension and inflammation associated with transactivation of NF‐κB in septic and non‐septic shock.     

Bis‐(3‐hydroxyphenyl) diselenide inhibits LPS‐stimulated iNOS and COX‐2 expression in RAW 264.7 macrophage cells through the NF‐kB inactivation

Objectives Previously, we reported that diaryl diselenide compounds have strong inhibitory effects on lipopolysaccharide (LPS)‐induced nitric oxide (NO) production in macrophages. In this study, we investigated the molecular mechanisms underlying NO suppression and prostaglandin E₂ (PGE₂) production by diaryl diselenide compounds, bis‐(2‐hydroxyphenyl) diselenide (DSE‐A), bis‐(3‐hydroxyphenyl) diselenide (DSE‐B), bis‐(4‐hydroxyphenyl) diselenide (DSE‐C), dipyridyl diselenide (DSE‐D) and diphenyl diselenide (DSE‐E). Methods The effect of these compounds on NO suppression and PGE₂ production was investigated in RAW 264.7 macrophages. Key findings Our data indicate that of the above, DSE‐B most potently inhibits NO and PGE₂ production, and that it also significantly reduces the releases of tumour necrosis factor (TNF)‐α, interleukin(IL)‐1β and IL‐6. Consistent with these observations, DSE‐B also reduced the protein levels of inducible NO synthase (iNOS) and cyclooxygenase‐2 (COX‐2), and the mRNA levels of iNOS, COX‐2, TNF‐α, IL‐1β and IL‐6. Furthermore, DSE‐B inhibited LPS‐induced nuclear factor‐κB (NF‐κB) activation, which was associated with the prevention of the inhibitor κB‐α (IκB‐α) degradation and a subsequent reduction in nuclear p65 protein levels. Conclusions Taken together, our data suggest that the anti‐inflammatory properties of DSE‐B are due to reduction in the expression of iNOS, COX‐2, TNF‐α, IL‐1β and IL‐6 through the down‐regulation of NF‐κB binding activity.     

Differential Inhibitory Effects of the Polyphenol Ellagic Acid on Inflammatory Mediators NF‐κB,iNOS, COX‐2, TNF‐α, and IL‐6 in 1,2‐Dimethylhydrazine‐Induced Rat Colon Carcinogenesis

Abstract: Dietary polyphenols have been found to possess preventive and therapeutic potential against several types of cancers. We investigated the effect of ellagic acid on colon cancer induced by 1,2‐dimethylhydrazine in rats. Male Wistar albino rats were divided into four groups. Group 1 served as control, group 2 rats received ellagic acid 60 mg/kg bodyweight/every day p.o. throughout the experiment. Rats from groups 3 and 4 were given subcutaneous (s.c.) injections of 1,2‐dimethylhydrazine (20 mg/kg body weight) once a week for the first 15 weeks; rats in group 4 received ellagic acid as in group 2 after the last injection of 1,2‐dimethylhydrazine and continued till the end of the experimental period of 30 weeks. 1,2‐dimethylhydrazine‐induced rats exhibited alterations in cancer tumour markers [5′‐nucleotidase (5′‐ND), gamma glutamyl transpeptidase (γ‐GT), carcinoembryonic antigen (CEA), alphafetoprotein (AFP) and cathepsin‐D (CD)]; pathophysiological markers [alkaline phosphatase (ALP) and lactate dehydrogenase (LDH)] and oral administration of ellagic acid restored the levels of these marker enzymes. Nuclear factor‐kappa B (NF‐κB) actively involved in the regulation of both pro‐inflammatory proteins [inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2)] and pro‐inflammatory cytokines [tumour necrosis factor (TNF)‐α and interleukin (IL)‐6] and in our study 1,2‐dimethylhydrazine‐induced group exhibited elevated expressions of all these inflammatory proteins. Ellagic acid administration reduced the expressions of NF‐κB, COX‐2, iNOS, TNF‐α and IL‐6 as confirmed by immunohistochemical, immunoblot and immunofluorescence analysis during 1,2‐dimethylhydrazine‐induced colon carcinogenesis. In conclusion, ellagic acid demonstrates anti‐inflammatory property by iNOS, COX‐2, TNF‐α and IL‐6 down‐regulation due to inhibition of NF‐κB and exerts its chemopreventive effect on colon carcinogenesis.     

Daphnetin inhibits TNF‐α and VEGF‐induced angiogenesis through inhibition of the IKKs/IκBα/NF‐κB,Src/FAK/ERK1/2 and Akt signalling pathways

Coumarins, identified as plant secondary metabolites possess diverse biological activities including anti‐angiogenic properties. Daphnetin (DAP), a plant derived dihydroxylated derivative of coumarin has shown significant pharmacological properties such as anticancer, anti‐arthritic and anti‐inflammatory. The present study was performed to investigate the anti‐angiogenic potential of DAP, focusing on the mechanism of action. The in vivo anti‐angiogenic potential of DAP was evaluated by vascular endothelial growth factor (VEGF)‐induced rat aortic ring (RAR) assay and chick chorioallantoic membrane (CAM) assay. For in vitro evaluation, wounding migration, transwell invasion, tube formation and apoptosis assays were performed on VEGF (8 ng/mL)‐induced human umbilical vein endothelial cells (HUVECs). The cellular mechanism of DAP was examined on TNFα (10 ng/mL) and VEGF‐induced HUVECs by extracting the mRNA and protein levels using RT‐qPCR and western blotting. Our data demonstrated that DAP inhibited the in vivo angiogenesis in the RAR and CAM assay. DAP also inhibited the different steps of angiogenesis, such as migration, invasion, and tube formation in HUVECs. DAP inhibited nuclear factor‐κB signalling together including TNF‐α induced IκBα degradation; phosphorylation of IκB kinase (IKKα/β) and translocation of the NF‐κB‐p65 protein. Furthermore, western blotting revealed that DAP significantly down‐regulated the VEGF‐induced signalling such as c‐Src, FAK, ERK1/2 and the related phosphorylation of protein kinase B (Akt) and VEGFR2 expressions. DAP reduced the elevated mRNA expression of iNOS, MMP2 and also, induced apoptosis in VEGF‐stimulated HUVECs by the caspase‐3 dependent pathway. Taken together, this study reveals that DAP may have novel prospective as a new multi‐targeted medication for the anti‐angiogenesis and cancer therapy.     

Proanthocyanidin protects against cisplatin‐induced oxidative liver damage through inhibition of inflammation and NF‐κβ/TLR‐4 pathway

Although cisplatin (CIS) is a highly effective anticancer drug, hepatotoxicity is one of the most common adverse effects associated with its use. Recently, reactive oxygen species (ROS) and inflammation are suggested to be key factors in the pathophysiology of CIS‐induced acute liver damage. The aim of this study is to investigate the possible protective effect of proanthocyanidin (PRO) against CIS‐induced acute hepatotoxicity. Rats were divided into four groups: 1, Control; 2, PRO; 3, CIS; and 4, PRO + CIS. Biochemical studies and histopathology were used to assess liver damage. ROS, inflammatory cytokines, nuclear factor kappa beta (NF‐κβ), inducible cyclooxygenase enzyme (COX‐2), inducible nitric oxide synthase (iNOS), toll‐like receptor‐4 (TLR‐4) gene expression, and apoptotic markers were also assessed. PRO pretreatment protected the liver against CIS‐induced toxicity as indicated by decreased plasma levels of liver function enzymes and the normal liver histopathology observed in the PRO + CIS group. PRO pretreatment also diminished indicators of oxidative stress in the liver, including nitric oxide (NO) and malondialdehyde (MDA). It also increased the antioxidants, reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in the liver. Plasma interleukin‐1 beta (IL‐1β), IL‐6, and tumor necrosis factor‐alpha (TNF‐α) were all reduced. Liver gene expression of NF‐κβ, COX‐2, iNOS, and TLR‐4 were all downregulated. Furthermore, PRO administration downregulated the liver expression of the apoptotic marker, Bax, while upregulated the antiapoptotic marker, Bcl2. In conclusion, our results revealed that PRO may protect against CIS‐induced acute liver damage mainly through inhibition of ROS, inflammation, and apoptosis.     

Anti‐inflammatory effects of synthetic compound KT‐14480 in lipopolysaccharide‐stimulated microglia cells

Objectives Neurodegenerative diseases have a prominent inflammatory component. Several synthetic fluorovinyloxyacetamide derivatives were screened by microglia cell‐based assay in order to identify novel compounds that inhibit the inflammatory activation of microglia. Methods Microglia cell‐based nitric oxide assay was employed to screen the compounds. RT‐PCR and ELISA were conducted to evaluate the expression of inflammatory gene expression. Molecular mechanisms were determined by western blot analysis, immunocytochemistry, EMSA, and microglia/neuroblastoma cocultures. Key findings A fluorovinyloxyacetamide compound KT‐14480 significantly suppressed nitric oxide production in lipopolysaccharide‐stimulated microglia cells. KT‐14480 also suppressed the secretion and expression of several inflammatory mediators such as tumour necrosis factor‐α, interleukin‐1β and inducible nitric oxide synthase. Additional studies showed that these inhibitory effects were accompanied by the suppression of nuclear factor‐κB and neuroprotection in the microglia/neuroblastoma coculture. Conclusions Our results indicate that the anti‐inflammatory compound KT‐14480 may be a novel therapeutic drug candidate against neuroinflammatory diseases.     

Diallyl sulfide alleviates cisplatin‐induced nephrotoxicity in rats via suppressing NF‐κB downstream inflammatory proteins and p53/Puma signalling pathway

Despite being a potent anticancer drug, nephrotoxicity is an adverse effect which renders the clinical use of cisplatin (Cis) limited. The protective role of diallyl sulfide (DAS); a naturally occurring organo‐sulfide, present in garlic, in cisplatin‐induced nephrotoxicity has been reported earlier. However, the mechanism through which DAS exerts its nephroprotective activity remains elusive. The aim of the current study was to elucidate the possible mechanisms underlying the reno‐protective effect of DAS in cisplatin‐induced nephrotoxicity in rats. DAS was given at 2 dose levels; 50 and 100 mg/kg, orally for 4 consecutive days, starting 1 hour after administration of single dose of cisplatin (3.5 mg/kg, intraperitoneally [i.p.]). The Cis‐induced elevation in serum urea and creatinine, degree of histopathological alterations was significantly ameliorated in cisplatin groups co‐treated with DAS. In addition, DAS significantly restored Cis‐depleted glutathione (GSH) content and superoxide dismutase (SOD) activity and attenuated Cis‐elevated Malondialdehyde (MDA) level. Also, DAS significantly reduced Cis‐increased renal expression of nuclear factor kappa B (NF‐κB) and subsequent pro‐inflammatory mediators; tumour necrosis factor alpha (TNF‐α), interleukin‐1β (IL‐1β), intercellular adhesion molecule‐1 (ICAM‐1) and inducible nitric oxide synthase (iNOS) in kidney tissues. Moreover, co‐treatment with DAS significantly inhibited Cis‐increased caspase‐8 and ‐9 levels. Additionally, DAS significantly mitigated Cis‐induced protein expression of p53, Puma, and Bax while, it significantly restored Cis‐reduced protein expression of Bcl‐xL compared to the Cis group. In conclusion, these results demonstrate that DAS ameliorates cisplatin‐induced nephrotoxicity in rats through enhancement of antioxidant defense, reduction of inflammatory cytokine tissue levels as well as inhibition of apoptosis via p53/Puma signalling pathway.     

α‐Lipoic acid prolongs survival and attenuates acute kidney injury in a rat model of sepsis

Acute kidney injury is a frequent and serious complication in patients with severe sepsis. α‐Lipoic acid (ALA), a naturally occurring dithiol compound, has been shown to possess anti‐inflammatory and anti‐oxidative properties. In the present study we investigated whether ALA could attenuate acute kidney injury and improve survival in a rat model of sepsis. Rats were subjected to caecal ligation and puncture (CLP) to induce sepsis. α‐Lipoic acid (200 mg/kg) was administered by oral gavage either immediately (early treatment) or 12 h after the surgical procedure (delayed treatment). Both early and delayed ALA treatment effectively prolonged survival, improved pathological damage in kidney tissues and reduced serum blood urea nitrogen and creatinine levels in CLP‐induced septic rats. Furthermore, early treatment with ALA markedly inhibited the release of tumour necrosis factor‐α, interleukin (IL)‐6 and IL‐1β into the serum and reduced mRNA and protein expression of inducible nitric oxide synthase and high mobility group box 1 in kidney tissues from CLP‐induced rats. Finally, CLP‐induced nuclear factor‐κB activation in kidney tissues was significantly suppressed by early ALA treatment. Together, the results indicate that ALA is able to reduce mortality and attenuate acute kidney injury associated with sepsis, possibly by anti‐inflammatory actions. α‐Lipoic acid may be a promising novel agent for the treatment of conditions associated with septic shock.     

Fluoxetine Induces Apoptosis in Ovarian Carcinoma Cell Line OVCAR‐3 Through Reactive Oxygen Species‐Dependent Activation of Nuclear Factor‐κB

Abstract: The apoptotic effect of fluoxetine (FLX), an antidepressant, against human epithelial ovarian cancer cell lines OVCAR‐3 and SK‐OV‐3 was investigated in relation to the mitochondria‐mediated cell death process and nuclear factor (NF)‐κB activation. FLX‐induced mitochondrial membrane permeability change and formation of reactive oxygen species, leading to cell death. FLX‐induced increase in mitochondrial Bax levels, decrease in cytosolic Bid and Bcl‐2 levels, loss of the mitochondrial transmembrane potential, cytochrome c release, caspase‐3 activation and up‐regulation of p53. Oxidant scavengers and Bay 11‐7085 [an inhibitor of nuclear factor kappaB (NF‐κB) activation] prevented the FLX‐induced cell death, increase in phosphorylated inhibitory κB‐α and NF‐κB p65 levels, and binding of NF‐κB p65 to DNA. Results from this study suggest that FLX may exhibit apoptotic effect against ovarian cancer cell lines by inducing the mitochondrial membrane permeability change, which leads to cytochrome c release and subsequent caspase‐3 activation, through reactive oxygen species‐dependent activation of NF‐κB.     

Dehydroxymethylepoxyquinomicin,a novel nuclear factor‐κB inhibitor,prevents inflammatory injury induced by interferon‐γ and histamine in NCTC 2544 keratinocytes

1. The novel nuclear factor (NF)‐κB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) is a derivative of the antibiotic epoxyquinomicin C from Amycolatopsis sp. that has been found to inhibit tumour necrosis factor (TNF)‐α‐induced activation of NF‐κB by suppressing nuclear translocation of NF‐κB. The aim of the present study was to determine the effects of DHMEQ on interferon (IFN)‐γ‐ and histamine‐activated NCTC 2544 keratinocytes. 2. Keratinocytes were stimulated or not with 200 U/mL IFN‐γ and 10^?4 mol/L histamine in the absence or presence of different concentrations of DHMEQ (1, 5 and 10 μg/mL) or hydrocortisone (10^?5 mol/L), which was used as a reference anti‐inflammatory drug. After 48 h, each sample was tested for the presence of intercellular adhesion molecule (ICAM)‐1 by western blot analysis, as well as for the release of monocyte chemoattractant protein (MCP)‐1, RANTES and interleukin (IL)‐8 using specific sandwich ELISAs. To verify the effect of DHMEQ on cell viability of non‐stimulated NCTC 2544 keratinocytes, the 3‐(4,5‐dimethyl‐2 thiazoyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay was used. 3. The results showed that 10 μg/mL DHMEQ potently inhibited ICAM‐1 production (by 50%), as well as the release of MCP‐1 (to 25% of control), RANTES (to 5% of control) and IL‐8 (to 2% of control). The results of the MTT assay indicated that DHMEQ has no effect on cell viability. 4. In conclusion, DHMEQ inhibits the IFN‐γ‐ and histamine‐induced activation of the keratinocyte cell line NCTC 2544. The anti‐inflammatory effects of DHMEQ could be exploited by applying the drug topically alone or in combination with sub‐toxic concentrations of anti‐inflammatory drugs to producer a synergistic effect.     

The role of Syk/IĸB‐α/NF‐ĸB pathway activation in the reversal effect of BAY 61‐3606, a selective Syk inhibitor,on hypotension and inflammation in a rat model of zymosan‐induced non‐septic shock

Spleen tyrosine kinase (Syk), a non‐receptor tyrosine kinase, plays an important role in allergic diseases and inflammation. Syk triggers several intracellular signalling cascades including Toll‐like receptor signalling to activate inflammatory responses following fungal infection but the role of this enzyme in zymosan (ZYM)‐induced non‐septic shock and its impacts on hypotension and inflammation in rats is not well understood. This study was conducted to determine the effects of Syk inhibition on ZYM‐induced alterations in the expression and/or activities of Syk, inhibitor ?B (I?B)‐α, and nuclear factor‐?B (NF‐?B) p65. We also examined the effect of Syk inhibition on inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)‐2, and tumour necrosis factor (TNF)‐α, and activity of myeloperoxidase (MPO) that contribute to hypotension and inflammation. Administration of ZYM (500 mg/kg, ip) to male Wistar rats decreased blood pressure and increased heart rate. These changes were associated with increased expression and/or activities of Syk, NF‐κB p65, iNOS and COX‐2 and decreased expression of IκB‐α with enhanced levels of nitrite, nitrotyrosine, 6‐keto‐PGF_1α, and TNF‐α and activity of MPO in renal, cardiac and vascular tissues. ZYM administration also elevated serum and tissue nitrite levels. The selective Syk inhibitor BAY 61‐3606 (3 mg/kg, ip) given 1 hour after ZYM injection reversed all of these changes induced by ZYM. These results suggest that Syk/I?B‐α/NF‐?B pathway activation contributes to hypotension and inflammation caused by the production of vasodilator and proinflammatory mediators in the zymosan‐induced non‐septic shock model.     

Nonylphenol regulates cyclooxygenase‐2 expression via Ros‐activated NF‐κB pathway in sertoli TM4 cells

The aim of this study was to investigate the signaling pathways involved in the cyclooxygenase (COX)‐2 regulation induced by nonylphenol (NP) in mouse testis Sertoli TM4 cells. Our results showed that treatment of TM4 cells with NP increased COX‐2 protein expression and interleukin‐6 (IL)‐6 and prostaglandin E2 (PGE2) secretion in a dose‐dependent manner. Pretreatment with reactive oxygen species (ROS) scavenger, N‐acetylcysteine (NAC), attenuated NP‐induced ROS production, COX‐2 expression, and IL‐6 and PGE2 release in TM4 cells. Exposure to NP stimulated activation of NF‐κB, whereas the NF‐κB inhibitor, pyrrolidine dithiocarbamate, attenuated NP‐enhanced COX‐2 expression and IL‐6 and PGE2 release in TM4 cells in a dose‐dependent manner. Furthermore, NAC blocked NP‐induced activation of NF‐κB. In addition, inhibition of COX‐2 mitigated NP‐induced IL‐6 release. In conclusion, NP induced ROS generation, activation of NF‐κB pathway, COX‐2 upregulation, and IL‐6 and PGE2 secretion in TM4 cells. NP may regulate COX‐2 expression via ROS‐activated NF‐κB pathway in Sertoli TM4 cells. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1144–1152, 2015.     

Puerarin Inhibits C‐Reactive Protein Expression via Suppression of Nuclear Factor κB Activation in Lipopolysaccharide‐Induced Peripheral Blood Mononuclear Cells of Patients with Stable Angina Pectoris

Abstract: Puerarin (4′‐7‐dihydroxy‐8‐β‐d ‐glucosylisoflavone), the most abundant isoflavone‐C‐glucoside extracted from the root of the plant Pueraria lobata, has demonstrated anti‐inflammatory activity in cellular models of inflammation. In this report, we examined the ability of puerarin to modulate C‐reactive protein (CRP) expression and key molecules in the nuclear factor kappa B (NF‐κB) pathway to determine its molecular target. The protein and mRNA levels of CRP were determined in lipopolysaccharide (LPS)‐induced peripheral blood mononuclear cells of patients with unstable angina pectoris. Also, we detected the I‐κBα phosphorylation and the p65NF‐κB expression in peripheral blood mononuclear cells under our experimental condition. The results indicated that puerarin inhibited the expression of the protein and mRNA levels of CRP in LPS‐induced peripheral blood mononuclear cells. Subsequently, we determined that the inhibition of CRP expression was because of a dose‐dependent inhibition of phosphorylation and degradation of inhibitor kappaB(I‐κB), which resulted in a reduction of p65NF‐κB nuclear translocation. We conclude that puerarin acts as an anti‐inflammatory agent by blocking NF‐κB signalling, and may possibly be developed as a useful agent for the chemoprevention of atherosclerosis.     

Effect of NF‐κB Decoy Oligodeoxynucleotide on LPS/High‐Fat Diet‐Induced Atherosclerosis in an Animal Model

Abstract: Atherosclerosis is a chronic inflammatory process occurring in the walls of arteries, in large part due to the accumulation of inflammatory cells. This study was conducted to determine the effect of nuclear factor (NF)‐κB decoy oligodeoxynucleotide (ODN) in an atherosclerosis animal model. The mice received i.p. injections of lipopolysaccharide (LPS, 2 mg/kg) three times a week to induce atherosclerotic change, and fed an atherogenic diet for 12 weeks. NF‐κB decoy ODN (0.4 mg/kg) was injected into the tail vein. Treatment with NF‐κB decoy ODN decreased pro‐inflammatory cytokines, tumour necrosis factor (TNF)‐α and interleukin (IL)‐1β and inflammatory markers, vascular adhesion molecule (VCAM)‐1 and intercellular adhesion molecule (ICAM)‐1, in the LPS/Fat‐induced mice. In addition, the expression of proteins related to fibrosis, transforming growth factor (TGF)‐β1 and fibronectin were markedly decreased in the mice treated with NF‐κB decoy ODN compared with the LPS/Fat‐induced mice without decoy ODN treatment. These data suggest that NF‐κB decoy ODN may exert an inhibitory effect on the expression levels of pro‐inflammatory cytokines and cell adhesion molecules in atherosclerotic mice.