Effect of the Acidic Dental Resin Monomer 10‐methacryloyloxydecyl Dihydrogen Phosphate on Odontoblastic Differentiation of Human Dental Pulp Cells

Although 10‐methacryloyloxydecyl dihydrogen phosphate (10‐MDP) is frequently used as an acidic resin monomer in dental adhesives, its effect on dental pulp cells (DPCs) has been rarely reported. The purpose of this study was to examine the effects of 10‐MDP on the inflammatory response and odontoblastic differentiation of DPCs at minimally toxic concentrations. We found that 10‐MDP caused the release of inflammatory cytokines including NO, PGE_2, iNOS, COX‐2, TNF‐α, IL‐1β, IL‐6 and IL‐8 in a concentration‐dependent manner. In addition, 10‐MDP reduced alkaline phosphatase activity, mineralization nodule formation and mRNA expression of odontoblastic differentiation markers such as dentin sialophosphoprotein, dentin matrix protein‐1, osterix and Runx2 in a concentration‐dependent manner with low toxicity. In addition, 10‐MDP induced activation of nuclear factor‐E2‐related factor 2 (Nrf2) and its target gene, haeme oxygenase‐1 (HO‐1). We evaluated whether the effect of 10‐MDP was related to the induction of HO‐1 and found that treatment with a selective inhibitor of HO‐1 reversed the production of 10‐MDP‐mediated pro‐inflammatory cytokines and the inhibition of differentiation markers. Pre‐treatment with either a GSH synthesis inhibitor or antioxidants blocked 10‐MDP‐induced mitogen‐activated protein kinases (MAPKs), Nrf2 and NF‐κB pathways. Taken together, the results of this study showed that minimally toxic concentrations of 10‐MDP promoted an inflammatory response and suppressed odontoblastic differentiation of DPCs by activating Nrf2‐mediated HO‐1 induction through MAPK and NF‐κB signalling.     

Cyanidin‐3‐glucoside inhibits inflammatory activities in human fibroblast‐like synoviocytes and in mice with collagen‐induced arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint tissue inflammation. Cyanidin‐3‐glucoside (C3G) is a major component in the flavonoid family and has shown anti‐inflammatory, anti‐oxidant and anti‐tumour activity. In this study, we investigated the effects of C3G on lipopolysaccharides (LPS)‐induced inflammation on human rheumatoid fibroblast‐like synoviocytes (FLS) and on collagen‐induced arthritis (CIA) mice model. We treated FLS with C3G followed by LPS induction, the expressions of tumour necrosis factor alpha (TNF‐α), interleukin 1 beta (IL‐1β) and IL‐6 and the activation of nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) and mitogen‐activated protein kinase (MAPK) signalling pathway were analyzed. CIA was induced in mice and the arthritic mice were treated with C3G for 3 weeks. The disease severity was compared between control and C3G treated mice. The serum levels of TNF‐α, IL‐1β and IL‐6 were analyzed by ELISA. C3G inhibited LPS‐induced TNF‐α, IL‐1β and IL‐6 expression in FLS. Moreover, C3G inhibited LPS‐induced p65 production and IκBa, p38, ERK and JNK phosphorylation. Administration of C3G significantly attenuated disease in mice with CIA and decreased the serum level of TNF‐α, IL‐1β and IL‐6. C3G inhibited LPS‐induced inflammation in human FLS by inhibiting activation of NF‐κB and MAPK signalling pathway. C3G exhibited therapeutic effects in mice with CIA.     

Myrrh mediates haem oxygenase-1 expression to suppress the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages

Objectives To elucidate a novel anti‐inflammatory mechanism of myrrh against lipopolysaccharide (LPS)‐induced inflammation. Methods RAW264.7 macrophages were cultured in DMEM and then cells were treated with LPS or LPS plus a myrrh methanol extract (MME) for 24 h. The culture medium was collected for determination of nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)‐1β, and tumour necrosis factor (TNF)‐α, and cells were harvested by lysis buffer for Western blot analysis. Key findings Our data showed that treatment with the MME (1～100 µg/ml) did not cause cytotoxicity or activate haem oxygenase‐1 (HO‐1) protein synthesis in RAW264.7 macrophages. Furthermore, the MME inhibited LPS‐stimulated NO, PGE₂, IL‐1β and TNF‐α release and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)‐2 protein expression. Zn(II) protoporphyrin IX, a specific inhibitor of HO‐1, blocked the inhibition of iNOS and COX‐2 expression by the MME. Conclusions These results suggest that among mechanisms of the anti‐inflammatory response, the MME inhibited the production of NO, PGE₂, IL‐1β and TNF‐α by downregulating iNOS and COX‐2 gene expression in macrophages and worked through the action of HO‐1.     

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.     

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.     

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.     

Ethyl pyruvate protects rats from phosgene‐induced pulmonary edema by inhibiting cyclooxygenase2 and inducible nitric oxide synthase expression

Phosgene is a poorly water‐soluble gas penetrating the lower respiratory tract which can induce acute lung injury characterized by a latent phase of fatal pulmonary edema. Pulmonary edema caused by phosgene is believed to be a consequence of oxidative stress and inflammatory responses. Ethyl pyruvate (EP) has been demonstrated to have anti‐inflammatory and anti‐oxidative properties in vivo and in vitro. The potential therapeutic role of EP in phosgene‐induced pulmonary edema has not been addressed so far. In the present study, we aim to investigate the protective effects of EP on phosgene‐induced pulmonary edema and the underlying mechanisms. Rats were administered with EP (40 mg kg^?1) and RAW264.7 cells were also incubated with it (0, 2, 5 or 10 µm ) immediately after phosgene (400 ppm, 1 min) or air exposure. Wet‐to‐dry lung weight ratio (W:D ratio), nitric oxide (NO) and prostaglandin E₂ (PGE₂) production, cyclooxygenase2 (COX‐2) and inducible nitric oxide synthase (iNOS) expression, and mitogen‐activated protein kinases activities (MAPKs) were measured. Our results showed that EP treatment attenuated phosgene‐induced pulmonary edema and decreased the level of NO and PGE₂ dose‐dependently. Furthermore, EP significantly reduced COX‐2 expression, iNOS expression and MAPK activation induced by phosgene. Moreover, specific inhibitors of MAPKs reduced COX‐2 and iNOS expression induced by phosgene. These findings suggested that EP has a protective role against phosgene‐induced pulmonary edema, which is mediated in part by inhibiting MAPK activation and subsequently down‐regulating COX‐2 and iNOS expression as well as decreasing the production of NO and PGE₂. Copyright © 2011 John Wiley & Sons, Ltd.     

NF‐κB/p53‐activated inflammatory response involves in diquat‐induced mitochondrial dysfunction and apoptosis

Inflammation generated by environmental toxicants including pesticides could be one of the factors underlying neuronal cell damage in neurodegenerative diseases. In this study, we investigated the mechanisms by which inflammatory responses contribute to apoptosis in PC12 cells treated with diquat. We found that diquat induced apoptosis, as demonstrated by the activation of caspases and nuclear condensation, inhibition of mitochondrial complex I activity, and decreased ATP level in PC12 cells. Diquat also reduced the dopamine level, indicating that cell death induced by diquat is due to cytotoxicity of dopaminergic neuronal components in these cells. Exposure of PC12 cells to diquat led to the production of reactive oxygen species (ROS), and the antioxidant N‐acetyl‐cystein attenuated the cytotoxicity of caspase‐3 pathways. These results demonstrate that diquat‐induced apoptosis is involved in mitochondrial dysfunction through production of ROS. Furthermore, diquat increased expression of cyclooxygenase‐2 (COX‐2) and tumor necrosis factor‐α (TNF‐α) via inflammatory stimulation. Diquat induced nuclear accumulation of NF‐κB and p53 proteins. Importantly, an inhibitor of NF‐κB nuclear translocation blocked the increase of p53. Both NF‐κB and p53 inhibitors also blocked the diquat‐induced inflammatory response. Pretreatment of cells with meloxicam, a COX‐2 inhibitor, also blocked apoptosis and mitochondrial dysfunction. These results represent a unique molecular characterization of diquat‐induced cytotoxicity in PC12 cells. Our results demonstrate that diquat induces cell damage in part through inflammatory responses via NF‐κB‐mediated p53 signaling. This suggests the potential to generate mitochondrial damage via inflammatory responses and inflammatory stimulation‐related neurodegenerative disease.     

Dexmedetomidine preconditioning for myocardial protection in ischaemia‐reperfusion injury in rats by downregulation of the high mobility group box 1‐toll‐like receptor 4‐nuclear factor κB signalling pathway

Pharmacological preconditioning reduces myocardial infarct size in ischaemia‐reperfusion (I‐R) injury. Dexmedetomidine, a selective α₂‐adrenoceptor agonist, has a proven cardioprotective effect when administered prior to I‐R, although the underlying mechanisms for this effect are not fully understood. We evaluated whether dexmedetomidine preconditioning could induce a myocardio‐protective effect against I‐R injury by inhibiting associated inflammatory processes through downregulation of the high mobility group box 1 (HMGB1)‐toll‐like receptor 4 (TLR4)‐nuclear factor κB (NF‐κB) signalling pathway. Seventy rats were randomly assigned to seven groups: a control and six test groups, involving I‐R for 30 and 120 minutes, respectively, in isolated rat hearts and different pretreatment protocols with dexmedetomidine (10 nmol/L) as well as yohimbine (1 μmol/L) and recombinant HMGB1 peptide (rHMGB1; 20 μg/L), alone or in combination with dexmedetomidine. Cardiac function was recorded; myocardial HMGB1, TLR4, and NF‐κB activities and levels of tumour necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were measured as were lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary outflow. Dexmedetomidine preconditioning significantly improved cardiac function (P<.05), downregulated the expression of HMGB1‐TLR4‐NF‐κB, reduced levels of TNF‐α and IL‐6 in isolated ventricles during I‐R injury, and significantly reduced CK and LDH levels in coronary outflow (P<.05). All of these effects were partially reversed by yohimbine (P<.05) or rHMGB1 (P<.05). Dexmedetomidine preconditioning alleviated myocardial I‐R injury in rats through inhibition of inflammatory processes associated with downregulation of the HMGB1‐TLR4‐NF‐κB signalling pathway via activation at α₂‐adrenergic receptors.     

Asian sand dust causes subacute peripheral immune modification with NF‐κB activation

Asian sand dust (ASD), a type of particulate matter found in Asia, migrates to East Asia. The increased airborne spread of ASD has led to concerns regarding possible adverse health effects. Our group previously reported that ASD induces lung inflammation in mice, but it is still unclear whether ASD affects lymphoid organs. In this study, we investigated the effect of ASD on splenocytes in a mouse model of ASD exposure. ICR mice were intratracheally administered a single dose of normal saline (control) or ASD and were subsequently sacrificed 1 or 3 days later. TNF‐α production in bronchoalveolar lavage fluids was higher at day 1, but not at day 3, after ASD administration. The enzyme‐linked immunosorbent assay results showed that ASD administration increased mitogen‐induced IL‐2, TNF‐α, and IL‐6 production in splenocytes. Additionally, cell viability assay showed enhanced splenocyte proliferation at day 3, but not at day 1, after ASD administration. The electrophoretic mobility shift assay results demonstrated that nuclear factor κB (NF‐κB) was activated in splenocytes on day 3, but not on day 1. In particular, NF‐κB activation was detected in CD4⁺ and CD11b⁺ cells on day 3. These results suggest that ASD induces subacute inflammatory responses with NF‐κB activation in the spleen, in contrast to acute inflammation in the lungs. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 549–558, 2015.     

Inhibition of macrophage migration inhibitory factor (MIF) tautomerase activity suppresses microglia‐mediated inflammatory responses

Macrophage migration inhibitory factor (MIF), a pleiotropic pro‐inflammatory cytokine, is a key regulator in both innate and acquired immunity systems. MIF has become a promising drug target for inflammatory diseases. Apart from its cytokine activities, MIF is known to act as a d ‐dopachrome tautomerase. Our previous work has identified that 3‐[(biphenyl‐4‐ylcarbonyl)carbamothioyl]amino benzoic acid (Z‐590) exhibited a potent inhibitory activity against MIF. In this study, we investigate the effect of Z‐590 on lipopolysaccharide (LPS)‐activated microglial cell activation. Our results demonstrate that Z‐590 significantly decreases the production of nitric oxide (NO), tumour necrosis factor‐alpha (TNF‐α), interleukin (IL)‐6, IL‐1β, cyclooxygenase (COX‐2), inducible nitric oxide synthase (iNOS) as well as reactive oxygen species (ROS) involved in inhibiting MAKPs signalling pathway in LPS‐stimulated microglia cells. Furthermore, Z‐590 reduced cytotoxicity of activated microglia toward HT‐22 hippocampal cells in a microglia‐conditioned medium system. Taken together, these results indicate that MIF inhibitor Z‐590 elicits a potent inhibitor for microglia‐mediated neuroinflammation.     

MiR‐101a ameliorates AngII‐mediated hypertensive nephropathy by blockade of TGFβ/Smad3 and NF‐κB signalling in a mouse model of hypertension

Hypertensive nephropathy, clinically characterized by progressive renal fibrosis and inflammation, is a severe complication of hypertension. The objectives of this study were to investigate the roles of miR‐101a in relieving angiotensin II (Ang II)‐mediated hypertensive nephropathy and uncover the possible underlying mechanisms. A hypertensive mouse model was established via continuous 28‐day AngII infusion. Systolic blood pressure (SBP), ratio of urine albumin to creatinine, blood urea nitrogen (BUN), serum creatinine (Scr) and glomerular filtration rate (GFR) were evaluated. Dual luciferase reporter assay was used to explore the target of miR‐101a. mRNA levels of miR‐101a, TGFβRI, fibrotic markers (Collagen I and α‐SMA) and pro‐inflammatory cytokines (IL‐1β and TNF‐α) were determined by real‐time PCR. Protein levels of TGFβRI, Collagen I, α‐SMA, IL‐1β, TNF‐α, t‐p65, P‐p65, t‐Smad3, P‐Smad3, t‐IκBα and P‐IκBα were detected by western blot. MiR‐101a mimics significantly improved GFR and inhibited AngII‐induced increase in the ratio of urine albumin to creatinine, BUN and Scr. MiR‐101a mimics partially abolished AngII‐induced increase in the mRNA and protein level of fibrotic markers by targeting TGFβRI and inhibiting TGFβ/Smad3 pathway. Moreover, TGFβRI inhibitor galunisertib inhibited AngII‐mediated renal injury in mice with hypertensive nephropathy. Additionally, miR‐101a overexpression blocked AngII‐induced up‐regulation of pro‐inflammatory markers via suppressing NF‐κB pathway. MiR‐101a exhibited protective effects against hypertensive nephropathy via inhibiting TGFβ/Smad3 and NF‐κB signalling pathways.     

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.     

Expression of pro‐inflammatory cytokines and mediators induced by Bisphenol A via ERK‐NFκB and JAK1/2‐STAT3 pathways in macrophages

Macrophages not only play an important role in the innate immune response but also participate in many inflammatory and infectious diseases including asthma, diabetes, obesity, cardiovascular diseases, and cancers. Bisphenol A (BPA) is the most commonly used component for plastic products. However, BPA is an endocrine disruptor for mammals and participates in several inflammatory and infectious diseases. Up until now, there are no researches demonstrated the potential role of BPA in macrophage activation and its relative mechanism. BPA promoted the generation of proinflammatory cytokines IL‐1β, IL‐6, and TNFα in a concentration‐dependent manner (P < 0.05). BPA was identified to increase the expression of proinflammatory mediators NO and PGE2, and its upstream factors iNOS, COX2, and cPLA2 in a concentration‐dependent manner (P < 0.05). Phosphorylation and nuclear translocation of NF‐κB p65 were significantly induced by BPA via IκB degradation (P < 0.05). In addition, phosphorylation of ERK significantly induced by BPA at a concentration which was less than that for phosphorylation of p38 MAPK and JNK (P < 0.05). Furthermore, phosphorylation of STAT3 significantly induced by BPA at a concentration lower than that for phosphorylation of STAT1 (P < 0.05). Phosphorylation of JAK1 and JAK2 was also significantly induced by BPA in a concentration‐dependent manner (P < 0.05).