Tetrandrine regulates hepatic stellate cell activation via TAK1 and NF-κB signaling

We investigated the anti-fibrotic mechanism of tetrandrine, a bisbenzylisoquinoline alkaloid from the Chinese herb, Stephania tetrandra, on the immortalized HSC-T6 rat hepatic stellate cell line. Tetrandrine (0.39–50 μM) dose- and time-dependently inhibited HSC-T6 cell viability within 24 h and exhibited almost no cytotoxicity at concentrations lower than 6.25 μM in the presence of tumor necrosis factor-α (TNF-α). At a much high concentration (50 μM), tetrandrine caused fatal cytotoxity in both HSCs and hepatocytes. TNF-α time-dependently increased α-smooth muscle actin (α-SMA) expression, while a lower concentration of tetrandrine (6.25 μM) prior to TNF-α treatment reduced the expression of α-SMA and TNFR-1-associated death domain (TRADD). TNF-α treatment induced TGF-β-activated kinase-1 (TAK1) and c-Jun N-terminal kinase (JNK) phosphorylation, which were attenuated by tetrandrine. Furthermore, TNF-α treatment activated nuclear factor-κB (NF-κB) nuclear translocation and IκB-α degradation. Tetrandrine treatment prior to TNF-α reduced nuclear phosphorylated and total NF-κB p65, while the cytosolic IκB-α and NF-κB p65 levels significantly increased. In addition, treatment with only tetrandrine induced the cleavage of caspase-3 and PARP within a range of higher concentrations. Tetrandrine-induced apoptosis was confirmed by the TUNEL assay and flow-cytometric analysis. Treatment with only tetrandrine markedly reduced α-SMA expression, except for at lower concentrations of tetrandrine. A higher concentration of tetrandrine (25 μM) induced a significant increase in JNK and extracellular signal-regulated kinase (ERK) phosphorylation, NF-κB nuclear translocation and IκB-α degradation. In conclusion, the anti-fibrogenic effects of tetrandrine on HSCs involved a dosage-dependent signaling pathway, based on the tetrandrine concentration, by regulating TAK1, JNK and NF-κB. The present data provides strong evidence for the anti-fibrotic dosage-dependent signaling pathway of tetrandrine.     

Bilobalide abates inflammation,insulin resistance and secretion of angiogenic factors induced by hypoxia in 3T3-L1 adipocytes by controlling NF-κB and JNK activation

Obesity leads to inflammation and insulin resistance in adipose tissue. Hypoxia, observed in obese adipose tissue is suggested as a major cause of inflammation and insulin resistance in obesity. However, the role of hypoxia in adipose tissue during obesity and insulin resistance was not well established. Here we mainly explored the crosstalk between hypoxia induced inflammation, and insulin resistance and also secretion of angiogenic factors in 3T3-L1 adipocytes and possible reversal with bilobalide. Hypoxia for 24 h significantly (P ≤ 0.05) increased the secretion of MCP-1 (4.59 fold), leptin (2.96 fold) and reduced adiponectin secretion (2.93 fold). In addition, the mRNA level of resistin (6.8 fold) and TLR4 receptors (8.8 fold) was upregulated in hypoxic adipocytes. The release of inflammatory cytokines and expression of TLR4 receptors led to activation of JNK and NF-κB signalling. We further investigated the effects of JNK and NF-κB activation on insulin signalling receptors. The present study showed increased (P ≤ 0.05) serine 307 phosphorylation of IRS-1 (1.9 fold) and decreased expression of IRS-2 (0.53 fold) in hypoxic group showing hypoxia induced impairment in insulin signalling. Hypoxia significantly (P ≤ 0.05) increased basal glucose uptake (3.3 fold) as well as GLUT-1 expression in adipocytes indicating GLUT-1 mediated glucose uptake. Hypoxia for 24 h significantly increased (P ≤ 0.05) the expression of angiogenic factors. Bilobalide protected adipocytes from hypoxia induced inflammation and insulin resistance mainly by reducing inflammatory adipokine secretion, improving adiponectin secretion, reducing NF-κB/JNK activation, and inhibiting serine phosphorylation of IRS-1 receptors of insulin signalling pathway.     

β-Glucan modulates the lipopolysaccharide-induced innate immune response in rat mammary epithelial cells

Mastitis, caused by mammary pathogenic bacteria which are frequent implications of Escherichia coli, is an important disease affecting women and dairy animals worldwide. The β-glucan binding of dectin-1 can induce its own intracellular signaling and can mediate a variety of cellular responses. This work was to investigate the effect of β-glucan on the lipopolysaccharide (LPS)-induced in?ammatory response and related innate immune signaling in primary rat mammary epithelial cells. Cells were treated with serum-free medium added with a DMSO solution containing β-glucans at concentrations of 0, 1, 5, 25 μmol/L for 12 h, and then exposed to 10 μg/mL LPS for 40 min. Moreover, cells were pretreated with BAY 11-7082 to inhibit NF-κB and then successively exposed to 5 μmol/L β-glucan, 10 μg/mL LPS, 5 μmol/L β-glucan and 10 μg/mL LPS, according to the specific experimental design. Normal control cultures contained an equal volume of DMSO, which was collected at the same time. After incubating rat mammary epithelial cells for 40 min with 10 μg/mL LPS, TLR4, MyD88 and NF-κB expression all increased (P < 0.05), as did the secretion of TNF-α and IL-1β (P < 0.05), but IκB and β-casein expression both decreased (P < 0.05). Treatment with different concentrations of β-glucan for 12 h activated Dectin1/Syk, which subsequently suppressed TLR4, MyD88 and NF-κB expression and TNF-α and IL-1β secretion. However, it restored the IκB and β-casein expression that had been induced by the 40 min incubation with 10 μg/mL LPS. Pretreatment with BAY 11-7082 at 10 µmol/L for 2 h partially prevented NF-κB induction by LPS, but the presence of β-glucan prevented this inactivation. BAY 11-7082 could not simultaneously inhibit LPS induction of TLR4, MyD88 and β-glucan activation of Dectin1/Syk in rat mammary epithelial cells. These findings demonstrated that β-glucan activation of Dectin1/Syk attenuated LPS induction of TLR4/MyD88/NF-κB and inhibited the LPS-induced inflammation factors in mammary epithelial cells, thereby providing a possibly protective effect of β-glucan in the prevention of LPS-induced dysfunction in mammary epithelial cells.     

Antrodia camphorata suppresses lipopolysaccharide-induced nuclear factor-κB activation in transgenic mice evaluated by bioluminescence imaging

In an earlier study, we found that Antrodia camphorata inhibited the production of lipopolysaccharide (LPS)-induced cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by blocking nuclear factor-κB (NF-κB) activation in cultured RAW 264.7 macrophages. This study was aimed at evaluating the inhibitory effects of the fermented culture broth of A. camphorata in terms of LPS-induced NF-κB activation in transgenic mice by using a non-invasive, real-time NF-κB bioluminescence imaging technique. Transgenic mice carrying the luciferase gene under the control of NF-κB were given A. camphorata (570 mg/kg, p.o.) for three consecutive days and then injected with LPS (4 mg/kg, i.p.). In vivo imaging showed that treatment with LPS increased the luminescent signal, whereas A. camphorata suppressed the LPS-induced inflammatory response significantly. Ex vivo imaging showed that A. camphorata suppressed LPS-induced NF-κB activity in the small intestine, mesenteric lymph nodes, liver, spleen, and kidney. Immunohistochemical staining revealed that A. camphorata suppressed production of the LPS-induced tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NF-κB p65 subunit in these organs. Furthermore, A. camphorata attenuated the productions of LPS-induced TNF-α and IL-1β in serum from transgenic mice. We report the first confirmation of the anti-inflammatory action in vivo of this potentially beneficial mushroom.     

Protective effects of Acanthopanax vs. Ulinastatin against severe acute pancreatitis-induced brain injury in rats

ObjectivesTo observe the protecting effects of Acanthopanax and Ulinastatin against severe acute pancreatitis (SAP)-induced brain injury in rats.MethodsSAP-modeled rats were equally randomized into three groups: model group, Acanthopanax-treated group and Ulinastatin-treated group. A sham-operation group was used as negative control. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and IL-10 levels were assayed by enzyme linked immunosorbent assay (ELISA). Nuclear factor kappa B p65 (NF-κB p65) activity in the brain tissue was determined by immunohistochemistry. The mortality, pathological changes of the pancreas and brain, and expression of TNF-α mRNA, IL-6 mRNA and IL-10 mRNA in the brain tissue were observed at 6, 12 and 24 h after operations in all groups.ResultsThe mortality of the model group was significantly higher than that of both treatment groups at 24 h (P < 0.01). Serum levels of TNF-α and IL-6, activity of NF-κB p65, expression levels of TNF-α and IL-6 mRNA in the brain tissue, and the pathological scores of the pancreas and brain in the two treatment groups were lower than those in the model group at 12 and 24 h after operation (P < 0.01), while serum IL-10 and IL-10 mRNA expression levels of the brain tissue in the two treatment groups were higher. There was no significant difference in all indexes between Acanthopanax and Ulinastatin groups at all designated time points (P > 0.05).ConclusionsAcanthopanax and Ulinastatin have similar protecting effects against SAP-induced brain injury in rats.     

Anti-leukemic effects of gallic acid on human leukemia K562 cells: Downregulation of COX-2, inhibition of BCR/ABL kinase and NF-κB inactivation

Gallic acid (GA) induces apoptosis in various cancer cell lines. In this study, we investigated the apoptotic activity induced by GA on chronic myeloid leukemia (CML) cell line-K562 and the underlying mechanism. GA reduced the viability of K562 cells in a dose and time dependent manner. GA led to G₀/G₁ phase arrest in K562 cells by promoting p21 and p27 and inhibiting the levels of cyclin D and cyclin E. Further studies indicated apoptosis with impaired mitochondrial function as a result of deranged Bcl-2/Bax ratio, leakage of cytochrome c and PARP cleavage along with DNA fragmentation and by up-regulating the expression of caspase-3. GA also activated the protein expressions of fatty acid synthase ligand and caspase-8. GA is more effective in imatinib resistant-K562 (IR-K562) cells (IC₅₀ 4 μM) than on K562 cells (IC₅₀ 33 μM). GA inhibited cyclooxygenase-2 (COX-2) in K562 as well as IR-K562 cells appears to be COX-2 involved in the suppression of growth. Interestingly, GA also inhibited BCR/ABL tyrosine kinase and NF-κB. In conclusion, GA induced apoptosis in K562 cells involves death receptor and mitochondrial-mediated pathways by inhibiting BCR/ABL kinase, NF-κB activity and COX-2.     

Puerarin mediates hepatoprotection against CCl4-induced hepatic fibrosis rats through attenuation of inflammation response and amelioration of metabolic function

This study was designed to evaluate the potential effects of puerarin (PR), an effective isoflavonoid compound purified from Pueraria lobata, in treating hepatic fibrosis (HF) rats induced by carbon tetrachloride (CCl₄, 2 mL kg⁻¹ d⁻¹). Compared to model control, PR treatment effectively lowered the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb), total protein (TP) in HF rats. Masson stained analysis showed that the condition of HF rats was mitigated. Meanwhile, the tumor necrosis factor alpha (TNF-α), nuclear factor-kappa B (NF-κB) expressions were significantly down-regulated at protein level by PR intervention. Additionally, the activity of superoxide dismutase (SOD) was elevated, while the content of malondialdehyde (MDA) was lessened in liver tissue. As revealed by immunohistochemistry assay, PR therapy resulted in reduced production of transforming growth factor-βl (TGF-βl). Moreover, it also was attributed to decreased mRNA level of inducible nitric oxide synthase (iNOS) using RT-PCR analysis. These findings demonstrate that puerarin successfully reverses hepatotoxicity in CCl₄-induced HF rats via the underlying mechanisms of regulating serum enzymes and attenuating TNF-α/NF-κB pathway for anti-inflammation response, as well as improving metabolic function in liver tissue.     

Ghrelin inhibits interleukin-8 production induced by hydrogen peroxide in A549 cells via NF-κB pathway

Ghrelin, a novel growth hormone-releasing peptide, can influence appetite and induce positive energy balances. Previous studies have reported that ghrelin ameliorated inflammatory responses of the heart, liver and pancreas. We examined whether ghrelin inhibits the proinflammatory cytokine interleukin-8 production induced by hydrogen peroxide (H₂O₂) in human lung epithelia cell line A549 and which mechanism is related with this effect of ghrelin. A549 cells were preincubated with vehicle or ghrelin (0.1 to 1000 ng/mL) in a concentration-dependent manner and then H₂O₂ (0 to 50 μM) was added. The interleukin-8 released by A549 in the medium was determined by ELISA, the mRNA expressions of interleukin-8 and ghrelin receptor were detected by RT-PCR. We also examined the phosphorylation of NF-κB/p65 protein and the degradation of inhibitory protein-κB (I-κB) in A549 by western blot analysis, the NF-κB DNA-binding activity by electrophoretic mobility shift assay, and then detected the generation of reactive oxygen species (ROS) in A549 by nitroblue tetrazolium reduction assay. Cells treated with H₂O₂ (50 μM) exhibited significantly higher interleukin-8 production and ghrelin receptor mRNA expression compared with cells treated with vehicle alone (P < 0.05). Ghrelin inhibited H₂O₂-induced interleukin-8 production by A549 at both mRNA and protein levels in a concentration-dependent manner (P < 0.05). Moreover, ghrelin attenuated H₂O₂-triggered NF-κB activation dependent on I-κB degradation dose-dependently in A549, but the intracellular ROS level after application of H₂O₂ was not affected by ghrelin (1000 ng/mL). Together, these results suggest that ghrelin inhibits H₂O₂-induced interleukin-8 production in A549 cells by targeting on NF-κB pathway, but not by directly scavenging intracellular ROS.     

The effects of lead exposure on placental NF-κB expression and the consequences for gestation

The present study was designed to investigate the toxicity of lead exposure on the placenta at different dosages and the relationship with placental expression of NF-κB. A total of 67 unrelated Han Chinese pregnant women and 108 Wistar rats were included in this study. The rats were randomly divided into four groups for consumption of water with or without 0.025% lead acetate during various gestational periods; blood samples and placenta were harvested for analysis. Blood lead content was determined by atomic absorption spectrophotometry. Placental NF-κB expression was evaluated by immunohistochemistry. Placental cytoarchitecture was examined by histopathology and electronic microscopy. Fetal body weight, body length and placental weight was significantly lower (p < 0.05) in the lead-exposed rats compared to controls. Maternal blood lead levels in the rats negatively correlated with placental weight (r = 0.652, p < 0.01). Rat placenta showed focal necrosis in the decidua with trophoblast degeneration and fibrin deposition. Mitochondria were swollen and decreased in number, rough endoplasmic reticula were distended and ribosomal number on membranes decreased. In the human placenta, we did not find abnormal cytoarchitecture. On the other hand, placental expression of NF-κB in lead-exposed rats was significantly higher than that in controls and the expression of NF-κB in human placenta was positively correlated with maternal blood lead levels (r = 0.663, p < 0.01). These findings suggest that lead exposure at various gestational periods produce varied effects, with NF-κB activation following lead exposure. Injury to cytoplasmic organelles may interfere with the nutrition and oxygen exchange between mother and fetus, which may be contribute to abnormal pregnancy outcomes.     

2-Deoxy-d-glucose attenuates sevoflurane-induced neuroinflammation through nuclear factor-kappa B pathway in vitro

ObjectSevoflurane, one of the most commonly used anesthetics in clinic, induced neuroinflammation and caused cognitive impairment. 2-deoxy-d-glucose (2-DG) is a synthetic analogue of glucose and is clinically used in medical imaging safely.MethodsWe examined the effect of 2-DG on sevoflurane-induced neuroinflammation in the mouse primary microglia cells. Mouse microglia cells were treated with 4.1% sevoflurane for 6 h to examine the expression of interleukin (IL)-6 and tumor necrosis factor (TNF-α) and activation of nuclear factor-kappa B (NF-κB). Pyrrolidine dithiocarbamate (PDTC) or 2-DG was used 1 h before sevoflurane treatment.ResultsIn the present study, we found that sevoflurane increased level of IL-6 and TNF-α through activating NF-κB signaling, and that 2-DG reduced sevoflurane-induced increase in IL-6 and TNF-α and nuclear NF-κB in microglia cells.ConclusionOur data suggests that NF-κB signaling pathway could be a target for sevoflurane-induced neuroinflammation and 2-DG might be a potential therapy to prevent or treat sevoflurane-induced neuroinflammation.     

Calea uniflora Less. attenuates the inflammatory response to carrageenan-induced pleurisy in mice

Calea uniflora Less. (family Asteraceae), also named “arnica” and “erva-de-lagarto”, is a native plant to the South and Southeast of Brazil. This species was used to treat rheumatism, respiratory diseases, and digestive problems in Brazilian folk medicine. In vitro studies have shown the important biological effects of C. uniflora. However no studies have focused on the mechanism of action of anti-inflammatory activity of C. uniflora. The aim of this study was to evaluate the anti-inflammatory effects of the crude extract, its fractions, and isolated compounds obtained from of C. uniflora, using mouse model of carrageenan-induced inflammation. The following inflammatory parameters: leukocyte influx, degree of exudation, myeloperoxidase (MPO) and adenosine deaminase (ADA) activities, nitric oxide metabolites (NOx), proinflammatory cytokines and phosphorylation of the p65 subunit of NF-κB (p-p65 NF-κB), and p38 mitogen-activated protein kinase (p-p38 MAPK) levels were determined. The crude extract of C. uniflora, its fractions and its isolated compounds reduced the leukocyte influx, degree of exudation, MPO and ADA activities, NOx, TNF-α, IFN-γ, MCP-1 and IL-6 levels (p < 0.05). The isolated compounds reduced p-p65 NF-κB and p-p38 MAPK levels (p < 0.01). This study demonstrated that C. uniflora exhibits a significant anti-inflammatory activity via inhibition of the leukocyte influx and degree of exudation. These effects were associated with a decrease in the levels of several proinflammatory mediators. The mechanism of the anti-inflammatory action of C. uniflora may be, at least in part, via the inhibition of p65 NF-κB and p38 MAPK activation by the isolated compounds.     

Autophagic flux regulates microglial phenotype according to the time of oxygen-glucose deprivation/reperfusion

Microglial phenotype alternation is a potential novel pathogenic mechanism for cerebral ischemia. Cerebral ischemia induced autophagy aggravates inflammation and neural injury. However, the effect of autophagy in the modulation of microglial phenotype is still unknown. In this study, we investigated the role of autophagic flux in the alternation of microglial phenotype following oxygen glucose deprivation/reperfusion (OGD/R) in BV-2 cells. Inhibition of autophagic flux by NH₄Cl exposure significantly increased the level of microtubule-associated protein 1 light chain 3 (LC3)-II and p62 in control and OGD/R (12 h, 24 h and 48 h) groups, but did not change their expression in OGD/R 72 h group, indicating that autophagic flux was inhibited at OGD/R 72 h. Once autophagic flux was inhibited at OGD/R 72 h or at OGD/R 24 h (with NH₄Cl), BV-2 cells mainly showed M1 phenotype with increased tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and decreased M2 markers including interleukin-10 (IL-10), Arginase 1 (Arg-1), and brain derived neurotrophic factor (BDNF). Further study indicated that inhibition of autophagic flux activated NF-κB pathway and decreased the activity of cAMP-response element binding protein (CREB), which contributed to the alternation of microglial phenotype. Therefore, inhibition of autophagic flux regulated the alternation of microglial phenotype by modulating the balance between NF-κB and CREB.     

NF-κB activation and proinflammatory cytokines mediated protective effect of Indigofera caerulea Roxb. on CCl4 induced liver damage in rats

Indigofera caerulea Roxb. is a well known shrub among native medical practitioners in folk medicine used for the treatment of jaundice, epilepsy, night blindness and snake bites. It is also reported to have antioxidant and antimicrobial properties. However its actual efficacy and hepatoprotective mechanism in particular is uncertain. Thus the present study investigates the hepatoprotective effect of the methanolic extract of I. caerulea Roxb. leaves (MIL) and elucidation of its mode of action against carbon tetrachloride (CCl₄) induced liver injury in rats. HPLC analysis of MIL when carried out showed peaks close to standard ferulic acid and quercetin. Intragastric administration of MIL up to 2000 mg/kg bw, didn't show any toxicity and mortality in acute toxicity studies. During “in-vivo” study, hepatic injury was established by intraperitoneal administration of CCl₄ 3 ml/kg bw (30% CCl₄ in olive oil; v/v) twice a week for 4 weeks in Sprague–Dawley rats. Further, hepatoprotective activity of MIL assessed using two different doses (100 and 200 mg/kg bw) showed that intra-gastric administration of MIL (200 mg/kg bw) significantly attenuates liver injury. Investigation of the underlying mechanism revealed that MIL treatment was capable of reducing inflammation by an antioxidant defense mechanism that blocks the activation of NF-κB as well as inhibits the release of proinflammatory cytokine TNF-α and IL-1β. The results suggest that MIL has a significant hepatoprotective activity which might be due to the presence of phytochemicals namely analogues of ferulic acid and other phytochemicals which together may suppress the inflammatory signaling pathways and promote hepatoprotective activity against CCl₄ intoxicated liver damage.     

Astilbin protects diabetic rat heart against ischemia–reperfusion injury via blockade of HMGB1-dependent NF-κB signaling pathway

Astilbin, a flavonoid compound was isolated from the rhizome of Smilax china L. In this study, we investigated the anti-myocardial ischemia and reperfusion (I/R) injury effect of Astilbin on diabetic rats in vivo and elucidated the potential mechanism in vitro. The results showed that Astilbin significantly attenuated hypoxia-induced cell injury in a concentration-dependent manner. Treatment of H9c2 cells with Astilbin at 15 μM blocked nuclear factor kappaB (NF-κB) phosphorylation by blocking High-mobility group box protein 1 (HMGB1) expression. Treatment of diabetic rats with Astilbin by intravenous injection (i.v.) at a single dose of 50 mg/kg protected the rats from myocardial I/R injury as indicated by decreasing infarct volume, improving hemodynamics and reducing myocardial damage, and also lowered serum levels of pro-inflammatory factors, reduced HMGB1 and phosphorylated NF-κB expression in ischemic myocardial tissue from diabetic rats. Additionally, treatment of diabetic rats with Astilbin at dose of 50 mg/kg by i.v. for continuous 14 days attenuated cardiac remodeling in the model myocardial I/R injury. These protective effects suggested that Astilbin might be due to block of the myocardial inflammatory cascade via the HMGB1-dependent NF-κB signaling pathway.     

Cryptotanshinone protects against IL-1β-induced inflammation in human osteoarthritis chondrocytes and ameliorates the progression of osteoarthritis in mice

Osteoarthritis (OA) is a common degenerative disease characterized by progressive erosion of articular cartilage, subchondral bone sclerosis and synovitis. Cryptotanshinone (CTS), an active component extracted from the root of Salvia miltiorrhiza Bunge, has been shown to have potent anti-inflammatory effects. However, its effects on OA have not been clearly elucidated. This study aimed to assess the effect of CTS on human OA chondrocytes and mice OA models. Human OA chondrocytes were pretreated with CTS (5, 10 and 20 μM) for 2 h and subsequently stimulated with IL-1β for 24 h. Production of NO, PGE2, IL-6, TNF-α was evaluated by the Griess reaction and ELISA. The protein expression of COX-2, iNOs, MMP-3, MMP13, COX-2, ADAMTS-5, JNK, p-JNK, ERK, p-ERK, p38, p-p38, p-IKKα/β, p65, p-p65, IκB-α, and p-IκB-α was tested by Western blot. In vivo, the severity of OA was determined by histological analysis. We found that CTS significantly inhibited the IL-1β-induced production of NO and PGE2; expression of COX-2, iNOS, MMP-3, MMP-13, and ADAMTS-5. Furthermore, CTS in dramatically suppressed IL-1β-stimulated NF-κB and MAPK activation. Immunofluorescence staining demonstrated that CTS could suppress IL-1β-induced phosphorylation of p65 nuclear translocation. In vivo, treatment of CTS prevented the destruction of cartilage and the thickening of subchondral bone in mice OA models. These results indicate that the therapeutic effect of CTS on OA is accomplished through the inhibition of both NF-κB and MAPK signaling pathways. Our findings provide the evidence to develop CTS as a potential therapeutic agent f or patients with OA.     

Oxidative stress and apoptosis are induced in human endothelial cells exposed to urban particulate matter

Correlations between exposure to particle matter (PM) with an aerodynamic diameter ⩽ 2.5 or 10 μm (PM_2.5 and PM₁₀, respectively) with cardiovascular effects have been demonstrated recently. Endothelial cells seem to play a relevant role in the responses to PM due to their participation in pro-inflammatory events. In this study we determined the effect of PM_2.5 and PM₁₀ from Mexico City on human endothelial cells by means of evaluating reactive oxygen species (ROS), nitric oxide (NO), NF-κB translocation and cell death. For this purpose we used human umbilical vein endothelial cells (HUVEC) as a model.The production of ROS was determined by the reduction of H₂DCFDA and NO by Griess reagent. The translocation of NF-κB was evaluated by Electrophoretic Mobility Shift Assay (EMSA) and the cellular death by the translocation of phosphatidylserine. TNF-α was used as a positive control for endothelial cell activation.PM_2.5 and PM₁₀ induced the production of ROS (77% and 126% increase, respectively, vs. control) and NO (up to 132% and 233% increase, respectively, vs. control). PM_2.5 and PM₁₀ also induced the nuclear translocation of NF-κB. All these events were associated with apoptosis. In conclusion, the activation of HUVEC induced by PM_2.5 and PM₁₀ is related with an oxidative stress, suggesting that these particles may participate in the development of cardiovascular and inflammatory diseases.     

Anti-inflammatory effect of corymbocoumarin from Seseli gummiferum subsp. corymbosum through suppression of NF-κB signaling pathway and induction of HO-1 expression in LPS-stimulated RAW 264.7 cells

This study investigated the anti-inflammatory activity of corymbocoumarin, an angular-type pyranocoumarin isolated from Seseli gummiferum subsp. corymbosum in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Corymbocoumarin not only inhibited the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), but also inhibited the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Corymbocoumarin also attenuated pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Investigation of the effect on nuclear factor κB (NF-κB) signaling pathway showed that corymbocoumarin inhibited the phosphorylation of Akt and inhibitory κB (IκB)-α and decreased the subsequent translocation of the p65 and p50 NF-κB subunits to the nucleus. A further study revealed that corymbocoumarin exerted anti-inflammatory activity through induction of heme oxygenase (HO)-1 expression. The in vivo study showed that corymbocoumarin (20 mg/kg, i.p.) reduced paw swelling in carrageenan-induced acute inflammation model. Taken together, these results suggest that corymbocoumarin exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells by suppressing NF-κB activation and inducing HO-1 expression. Corymbocoumarin may provide a useful therapeutic approach for inflammation-associated diseases.     

Ketamine attenuates sepsis-induced acute lung injury via regulation of HMGB1-RAGE pathways

High mobility group box protein 1 (HMGB1) and receptor for the advanced glycation end product (RAGE) play important roles in the development of sepsis-induced acute lung injury (ALI). Ketamine is considered to confer protective effects on ALI during sepsis. In this study, we investigated the effects of ketamine on HMGB1-RAGE activation in a rat model of sepsis-induced ALI. ALI was induced in wild type (WT) and RAGE deficient (RAGE^−/−) rats by cecal ligation and puncture (CLP) or HMGB1 to mimic sepsis-induced ALI. Rats were randomly divided to six groups: sham-operation + normal saline (NS, 10 mL/kg), sham-operation + ketamine (10 mg/kg), CLP/HMGB1 + NS (10 mL/kg), CLP/HMGB1 + ketamine (5 mg/kg), CLP/HMGB1 + ketamine (7.5 mg/kg), and CLP/HMGB1 + ketamine (10 mg/kg) groups. NS and ketamine were administered at 3 and 12 h after CLP/HMGB1 via intraperitoneal injection. Pathological changes of lung, inflammatory cell counts, expression of HMGB1and RAGE, and concentrations of various inflammatory mediators in bronchoalveolar lavage fluids (BALF) and lung tissue were then assessed. Nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathways in the lung were also evaluated. CLP/HMGB1 increased the wet to dry weight ratio and myeloperoxidase activity in lung, the number of total cells, neutrophils, and macrophages in the BALF, and inflammatory mediators in the BALF and lung tissues. Moreover, expression of HMGB1and RAGE in lung tissues was increased after CLP. Ketamine inhibited all the above effects. It also inhibited the activation of IκB-α, NF-κB p65, and MAPK. Ketamine protects rats against HMGB1-RAGE activation in a rat model of sepsis-induced ALI. These effects may partially result from reductions in NF-κB and MAPK.