RAGE/NF-κB Pathway Mediates Lipopolysaccharide-Induced Inflammation in Alveolar Type I Epithelial Cells Isolated from Neonate Rats

Alveolar type I epithelial cells (AECIs) play an important role in the pathogenesis of acute lung injury. The receptor for advanced glycation end-products (RAGEs) is expressed at a high basal level in AECIs, and its soluble isoform is suggested as a marker of AECI injury. However, the molecular mechanism by which RAGE mediates inflammatory injury in AECIs remains elusive. In this study, we established lipopolysaccharide (LPS)-induced inflammation in AECIs isolated from neonate rats as the experimental model and investigated the role of RAGE/NF-κB signaling in mediating inflammatory response in AECIs. We found that LPS increased RAGE expression and the secretion of tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) in AECIs in a dose-dependent manner. Knockdown of RAGE significantly decreased TNF-α and IL-1β levels in conditioned medium of AECIs. Electrophoretic mobility shift assay (EMSA) showed that NF-κB activation was increased in AECIs treated by LPS. However, knockdown of RAGE inhibited both basic and LPS-induced NF-κB activity in AECIs. Finally, NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) significantly reduced LPS-induced upregulation of RAGE expression at both protein and messenger RNA (mRNA) levels in AECIs. Our results suggest that RAGE mediates inflammatory response in AECIs via activating NF-κB, and RAGE/NF-κB pathway presents potential target for the prevention and therapy of acute lung injury.     

The Link Between Unpredictable Chronic Mild Stress Model for Depression and Vascular Inflammation?

Inflammation has been suggested to be associated with stress-induced depression and cardiovascular dysfunction. Tumor necrosis factor alpha (TNF-α) is a major cytokine in the activation of neuroendocrine, immune, and behavioral responses. In this study, we investigated the effects of infliximab (a TNF-α inhibitor) on endothelium-dependent vascular reactivity, systemic blood pressure, and endothelial nitric oxide synthase (eNOS) immunoreactivity in the unpredictable chronic mild stress (UCMS) model of depression in rats. There was no significant change between all groups in the systemic blood pressure. In UCMS, endothelium-dependent relaxation of the smooth muscle in response to carbachol was significantly decreased with 50 % maximal response (E _max) and pD2 values compared with the controls. Infliximab was able to reverse this UCMS effect. Relaxation in response to the nitric oxide (NO) donor sodium nitroprusside and papaverine and KCl-induced contractile responses was similar between groups. In UCMS, decreased expression of eNOS was detected. Moreover, there was no significant change in UCMS?+?infliximab group with respect to control rats. Our results suggest that tumor necrosis factor-alpha (TNF-α) could be a major mediator of vascular dysfunction associated with UCMS, leading to decreased expression of eNOS.     

Novel Mechanisms of Action of the Biologicals in Rheumatic Diseases

Biological drugs targeting pro-inflammatory or co-stimulatory molecules or depleting lymphocyte subsets made a revolution in rheumatoid arthritis (RA) treatment. Their comparable efficacy in clinical trials raised the point of the heterogeneity of RA pathogenesis, suggesting that we are dealing with a syndrome rather than with a single disease. Several tumor necrosis factor-alpha (TNF-α) blockers are available, and a burning question is whether they are biosimilar or not. The evidence of diverse biological effects in vitro is in line with the fact that a lack of efficacy to one TNF-α agent does not imply a non-response to another one. As proteins, biologicals are potentially immunogenic. It has been recently raised that anti-drug antibodies (ADA) may affect their bioavailability and eventually the clinical efficacy through local formation of immune complexes and directly by preventing the interaction between the drug and TNF-α. Regular monitoring of drug and ADA levels appears the best way to tailor anti-TNF-α therapies. Owing to the pleiotropic characteristics of the target, anti-TNF-α blockers may affect several mechanisms beyond rheumatoid synovitis. As TNF-α plays a pivotal role in the induction of early atherosclerosis, treatment with TNF-inhibitors may modulate cholesterol handling, in particular, cholesterol efflux from macrophages. Side effects are a major issue because of the systemic TNF-α blocking action. The efficacy of an anti-C5 monoclonal antibody fused to a peptide targeting inflamed synovia in experimental arthritis opened the way for new strategies: Homing to the synovium of molecules neutralizing TNF would allow to maximize the therapeutic action avoiding the side effects.     

Geniposide Plays an Anti-inflammatory Role via Regulating TLR4 and Downstream Signaling Pathways in Lipopolysaccharide-Induced Mastitis in Mice

Geniposide is a medicine isolated from Gardenia jasminoides Ellis, which is a traditional Chinese herb that is widely used in Asia for the treatment of inflammation, brain diseases, and hepatic disorders. Mastitis is a highly prevalent and important infectious disease. In this study, we used a lipopolysaccharide (LPS)-induced mouse mastitis model and LPS-stimulated primary mouse mammary epithelial cells (mMECs) to explore the anti-inflammatory effect and the mechanism of action of geniposide. Using intraductal injection of LPS as a mouse model of mastitis, we found that geniposide significantly reduced the infiltration of inflammatory cells and downregulated the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). To further investigate the anti-inflammatory mechanism, we used LPS-stimulated mMECs as an in vitro mastitis model. The results of enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR) showed that geniposide inhibited the expression of TNF-α, IL-1β, and IL-6 in a dose-dependent manner. Western blot analysis demonstrated that geniposide could suppress the phosphorylation of inhibitory kappa B (IκBα), nuclear factor-κB (NF-κB), p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK). Geniposide also inhibited the expression of toll-like receptor 4 (TLR4) in the LPS-stimulated mMECs. In conclusion, geniposide exerted its anti-inflammatory effect by regulating TLR4 expression, which affected the downstream NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways. Thus, geniposide may be a potential drug for mastitis therapy.     

Docosahexanoic acid antagonizes TNF-α-induced necroptosis by attenuating oxidative stress,ceramide production,lysosomal dysfunction,and autophagic features

Objective

It was previously reported that docosahexanoic acid (DHA) reduces TNF-α-induced necrosis in L929 cells. However, the mechanisms underlying this reduction have not been investigated. The present study was designed to investigate cellular and biochemical mechanisms underlying the attenuation of TNF-α-induced necroptosis by DHA in L929 cells.

Methods

L929 cells were pre-treated with DHA prior to exposure to TNF-α, zVAD, or Necrostatin-1 (Nec-1). Cell death and survival were assessed by MTT and caspase activity assays, and microscopic visualization. Reactive oxygen species (ROS) were measured by flow cytometry. C16- and C18-ceramides were measured by mass spectrometry. Lysosomal membrane permeabilization (LMP) was evaluated by fluorescence microscopy and flow cytometry using Acridine Orange. Cathepsin L activation was evaluated by immunoblotting and fluorescence microscopy. Autophagy was assessed by immunoblotting of LC3-II and Beclin.

Results

Exposure of L929 cells to TNF-α alone for 24 h induced necroptosis, as evidenced by the inhibition of cell death by Nec-1, absence of caspase-3 activity and Lamin B cleavage, and morphological analysis. DHA attenuated multiple biochemical events associated with TNF-α-induced necroptosis, including ROS generation, ceramide production, lysosomal dysfunction, cathepsin L activation, and autophagic features. DHA also attenuated zVAD-induced necroptosis but did not attenuate the enhanced apoptosis and necrosis induced by the combination of TNF-α with Actinomycin D or zVAD, respectively, suggesting that its protective effects might be limited by the strength of the cell death insult induced by TNF-α.

Conclusions

DHA effectively attenuates TNF-α-induced necroptosis and autophagy, most likely via its ability to inhibit TNF-α-induced sphingolipid metabolism and oxidative stress. These results highlight the role of this Omega-3 fatty acid in antagonizing inflammatory cell death.     

Stevioside Plays an Anti-inflammatory Role by Regulating the NF-κB and MAPK Pathways in S. aureus-infected Mouse Mammary Glands

Mastitis is an inflammatory disease caused by microbial infection. Staphylococcus aureus is one of the primary bacteria responsible for mastitis. Stevioside is isolated from Stevia rebaudiana and is known to have therapeutic functions. This study was designed to evaluate the effects of stevioside in a mouse model of S. aureus-induced mastitis. In this study, the mouse mammary gland was infected with S. aureus to induce the mastitis model. The stevioside was administered intraperitoneally after the S. aureus infection was established. Hematoxylin–eosin (HE) staining, ELISA, Western blot, and q-PCR methods were used. The results show that stevioside significantly reduced the inflammatory cell infiltration and the levels of TNF-α, IL-1β, and IL-6 and the respective expression of their messenger RNAs (mRNAs). Further studies revealed that stevioside downregulated the TLR2, NF-κB, and (mitogen-activated protein kinase) MAPK signaling pathways in the S. aureus-infected mouse mammary gland. Our results demonstrate that stevioside reduced the expression of TNF-α, IL-1β, and IL-6 by inhibiting the phosphorylation of proteins in the NF-κB and MAPK signaling pathways dose-dependently, but that their mRNA expression was not obviously changed.     

Magnolol Inhibits Tumor Necrosis Factor-α-Induced ICAM-1 Expression via Suppressing NF-κB And MAPK Signaling Pathways in Human Lung Epithelial Cells

Magnolol is a traditional Chinese medicine from the root and bark of Magnolia officinalis. It has long been used to treat anxiety, cough, headache and allergies, as well as a variety of inflammations. Lung inflammation is a key event in the pathogenesis of asthma and chronic obstructive pulmonary disease. The present study sought to examine the effects of magnolol on tumor necrosis factor (TNF)-α-induced upregulation of intercellular adhesion molecule-1 (ICAM-1), activation of the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathway in cultured human pulmonary epithelial cells, and adhesion of human macrophage-like U937 cells to A549 cells. A549 cells were incubated with magnolol at 25 and 50 μmol/l. Then, 20 ng/ml TNF-α was used to activate the cells. Magnolol inhibited the growth of human pulmonary epithelial A549 cells in a dose- and time-dependent manner. Magnolol suppressed the adhesion of U937 cells to TNF-α-induced A549 cells. In cultured human pulmonary epithelial A549 cells, magnolol decreased TNF-α-induced upregulation of ICAM-1. Magnolol repressed TNF-α-induced activation of NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways in A549 cells by inhibiting phosphorylation of NF-κB, p38, extracellular signal-regulated kinase (ERK) 1/2, and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK). These findings support the hypothesis that magnolol inhibits the inflammatory process in lung epithelial A549 cells by suppressing the ICAM-1 and NF-κB and MAPK signaling pathways. Taken together, these results indicate that magnolol offers significant potential as a therapeutic treatment for inflammatory diseases of the lungs including asthma, sepsis, and chronic obstructive pulmonary disease.     

Curcumin Inhibits TLR2/4-NF-κB Signaling Pathway and Attenuates Brain Damage in Permanent Focal Cerebral Ischemia in Rats

Toll-like receptors 2 and 4 (TLR2/4) and the downstream nuclear factor-kappa B (NF-κB) signaling pathway, which mediate the inflammatory reaction in cerebral ischemia, were demonstrated to be involved in the extension of cerebral infarction and the aggravation of ischemic brain damage. Reports showed that curcumin provides neuroprotection against ischemic brain damage. In this study, we investigated whether curcumin inhibits the activation of TLR2/4-NF-κB signaling pathway in rats of permanent focal cerebral ischemia. Adult male Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (pMCAO). Curcumin was administered by intraperitoneal injection twice at 2 and 12 h after the onset of ischemia. Neurological deficit scores, cerebral infarct size, morphological characteristic, and cerebral water content were measured after 24 h of pMCAO. The enzymatic activity of myeloperoxidase (MPO) was assessed after 24 h of pMCAO. Expression of TLR2 and TLR4 in ischemic brain was determined by western blot. Expression of NF-κB p65 in ischemic brain was detected by immunohistochemistry and western blot. The release of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in blood was examined by ELISA. Curcumin significantly reduced neurological deficit scores, cerebral infarct size, neuronal damage, cerebral water content, and MPO activity. It also inhibited the expression of TLR2/4 and decreased the expression and activity of NF-κB p65 in rat brain. In addition, curcumin attenuated the release of TNF-α and IL-1β in blood. Our results suggest that curcumin reduces inflammatory reaction and brain damage in a rat model of permanent focal cerebral ischemia. The neuroprotective effect and anti-inflammatory property of curcumin in cerebral ischemia might be associated with the inhibition of TLR2/4-NF-κB signaling pathway.     

Wogonoside Ameliorates Lipopolysaccharide-Induced Acute Lung Injury in Mice

Wogonoside has been reported to have anti-inflammatory properties. In this study, we evaluated the effect of wogonoside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Male BALB/c mice with ALI, induced by intranasal instillation of LPS, were treated with wogonoside 1 h prior to LPS exposure. Mice treated with LPS alone showed significantly increased TNF-α, IL-6, and IL-1β levels in the bronchoalveolar lavage fluid (BALF). When pretreated with wogonoside, the TNF-α, IL-6, and IL-1β levels were significantly decreased. Meanwhile, wogonoside significantly inhibited LPS-induced increases in the macrophage and neutrophil infiltration of lung tissues and markedly attenuated myeloperoxidase activity. Furthermore, wogonoside inhibited the TLR4 expression and the phosphorylation of NF-κB p65, and IκB induced by LPS. In conclusion, our results indicate that wogonoside exhibits a protective effect on LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways.     

Inhibitory Effects of Rutin on the Endothelial Protein C Receptor Shedding In Vitro and In Vivo

Endothelial cell protein C receptor (EPCR) has important functions in regulation of coagulation and inflammation. EPCR shedding from the cell surface is mediated by tumor necrosis factor-α converting enzyme (TACE). Rutin is one of the major flavonoids from the buckwheat plant Fagopyrum tataricum. In this study, we investigated the effects of rutin on phorbol-12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and on cecal ligation and puncture (CLP)-mediated EPCR shedding. We used a CLP model because this model more closely resembles human sepsis. Data showed rutin was a potent inhibitor of PMA, TNF-α, IL-1β, and CLP-induced EPCR shedding by suppression of TACE expression. Treatment with rutin resulted in a decrease of PMA-stimulated phosphorylation of p38, extracellular regulated kinases 1/2, and c-Jun N-terminal kinase. These results suggest the potential application of rutin for treatment of PMA and CLP-mediated EPCR shedding.     

Dietary Selenium Deficiency Exacerbates Lipopolysaccharide-Induced Inflammatory Response in Mouse Mastitis Models

Selenium (Se) is an essential micronutrient that plays a critical role in anti-inflammatory processes and antioxidant defense system. In this study, we investigated the effects of dietary selenium deficiency on lipopolysaccharide (LPS)-induced mastitis in mouse models. Se content in the liver was assessed by fluorescent atomic absorption spectrometry. Glutathione peroxidase (GPx) activity in the blood, myeloperoxidase (MPO) activity, tumor necrosis actor alpha (TNF-α), and interleukin (IL)-1β in the supernatant of the mammary tissue were determined according to the corresponding kits. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions were evaluated by Western blotting. The results showed that the Se-deficient mouse model was successfully replicated, and selenium deficiency exacerbated mammary gland histopathology, increased the expressions of TNF-α and IL-1β, and facilitated the activation of iNOS and COX-2 in LPS-induced mouse mastitis. In conclusion, our studies demonstrated that selenium deficiency resulted in more severe inflammatory response in LPS-induced mouse mastitis.     

Patchouli Alcohol Dampens Lipopolysaccharide Induced Mastitis in Mice

Patchouli alcohol (PA), a tricyclic sesquiterpene isolated from Pogostemonis Herba, has been known to exhibit antioxidant, anti-inflammatory, and other important therapeutic activities. The aim of this study was to investigate the effects of PA on LPS-induced mastitis in vivo and the possible mechanism. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. Mice were pretreated with dexamethasone or PA 1 h before and 12 h after induction of LPS. The myeloperoxidase activity and inflammatory cytokines production in mammary tissues were determined. The effects of PA on NF-κB signal pathways were analyzed by Western blotting. The results showed that PA inhibited the LPS-induced TNF-α, IL-6, and IL-1β production in a dose manner. It was also observed that PA attenuated mammary histopathologic changes. Furthermore, Western blot analysis showed that PA could inhibit the phosphorylation of NF-κB and IκB induced by LPS. These results indicate that PA inhibits NF-κB signaling pathways to attenuate inflammatory injury induced by LPS. PA may be a potent therapeutic reagent for the prevention of mastitis.     

In Vivo and In Vitro Immunomodulatory Potential of Swertiamarin Isolated from Enicostema axillare (Lam.) A. Raynal That Acts as an Anti-inflammatory Agent

Swertiamarin is a secoiridoid glycoside found in Enicostema axillare (Lam) A. Raynal, a medicinal plant used as a depurative in the Indian system of traditional medicine. The present study evaluated the immunomodulatory activity of isolated swertiamarin. In vivo immunomodulatory activity of swertiamarin (2, 5, and 10 mg/kg b.w.) was evaluated in a model of sheep red blood cells (SRBC) by assessing its effect on organ weight, hemagglutinating antibody titer (HA), plaque-forming cells (PFC), quantitative hemolysis of SRBC, and delayed type hypersensitivity (DTH). In vitro immunomodulatory potential was studied on isolated splenocytes, neutrophils, and peritoneal macrophages. In silico immunomodulatory effects were evaluated by docking of swertiamarin on proinflammatory cytokines to confirm its potential. In in vivo studies, the animals treated with swertiamarin showed a significant (P?≤?0.05) increase in antibody titer, plaque-forming cells, and also in weight of the thymus and spleen. A decreased response to DTH reaction was recorded with the treatment of swertiamarin. In in vitro studies, treatment with swertiamarin modulated the messenger RNA (mRNA) and protein expression of IFN-γ, IL-10, and IL-4 significantly (P?≤?0.05) and also favored Th2-mediated response on concanavalin A (Con A)-induced splenocytes. The compound inhibited the release of free radicals significantly (P?≤?0.05) in phytohemagglutinin (PHA)-induced neutrophils and also ameliorated the mRNA and protein expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in lipopolysaccharide (LPS)-induced macrophages. In in silico, the best docked pose of swertiamarin with the target proteins (TNF-α, IL-1β, and IL-6) was confirmed that swertiamarin acted as an anti-inflammatory mediator.     

Sulforaphane Inhibits IL-1β-Induced Proliferation of Rheumatoid Arthritis Synovial Fibroblasts and the Production of MMPs,COX-2, and PGE2

This study was performed to define the effects of sulforaphane on interleukin-1β (IL-1β)-induced proliferation of rheumatoid arthritis synovial fibroblasts (RASFs), the expression of matrix metalloproteinases (MMPs) and cyclooxygenase (COX), and the production of prostaglandin E2 (PGE2) by RASFs. The proliferation of RASFs was evaluated with CCK-8 reagent in the presence of IL-1β with/without sulforaphane. The expression of MMPs, tissue inhibitor of metalloproteinase-1, COXs, intracellular mitogen-activated protein kinase signalings, including p-ERK, p-p38, p-JNK, and nuclear factor-kappaB (NF-kB), and the production of PGE2 were examined by Western blotting or semi-quantitative RT-PCR and ELISA. Sulforaphane inhibits unstimulated and IL-1β-induced proliferation of RASFs; the expression of MMP-1, MMP-3, and COX-2 mRNA and protein; and the PGE2 production induced by IL-1β. Sulforaphane also inhibits the phosphorylation of ERK-1/2, p-38, and JNK and activation of NF-kB by IL-1β. These results indicate that sulforaphane inhibits the proliferation of synovial fibroblasts, the expression of MMPs and COX-2, and the production of PGE2, which are involved in synovitis and destruction of RA, and suggest that sulforaphane might be a new therapeutic agent for RA.     

Effects of PPAR-γ Agonist Treatment on LPS-Induced Mastitis in Rats

PPAR-γ, a member of the nuclear receptor superfamily, plays an important role in lipid metabolism and inflammation. The aim of this study was to investigate the preventive effects of synthetic PPAR-γ agonist rosiglitazone on lipopolysaccharide (LPS)-induced mastitis in rats. The mouse model of mastitis was induced by the injection of LPS through the duct of the mammary gland. Rosiglitazone was injected 1 h before the induction of LPS intraperitoneally. The results showed that rosiglitazone attenuated the infiltration of inflammatory cells, the activity of myeloperoxidase (MPO), and the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in a dose-dependent manner. Additionally, Western blotting showed that rosiglitazone inhibited the phosphorylation of IκB-α and NF-κB p65. These results indicated that rosiglitazone has a protective effect on mastitis, and the anti-inflammatory mechanism of rosiglitazone on LPS-induced mastitis in rats may be due to its ability to inhibit NF-κB signaling pathways. PPAR-γ may be a potential therapeutic target against mastitis.     

Complex interactions between the components of the PI3K/AKT/mTOR pathway,and with components of MAPK,JAK/STAT and Notch-1 pathways,indicate their involvement in meningioma development

We investigated the significance of PI3K/AKT/mTOR pathway and its interactions with MAPK, JAK/STAT and Notch pathways in meningioma progression. Paraffin-embedded tissue from 108 meningioma patients was analysed for the presence of mutations in PIK3CA and AKT1. These were correlated with the expression status of components of the PI3K/AKT/mTOR pathway, including p85α and p110γ subunits of PI3K, phosphorylated (p)-AKT, p-mTOR, p-p70S6K and p-4E-BP1, as well as of p-ERK1/2, p-STAT3 and Notch-1, clinicopathological data and patient survival. A mutation in PIK3CA or AKT1 was found in around 9 % of the cases. Higher grade meningiomas displayed higher nuclear expression of p-p70S6K; higher nuclear and cytoplasmic expression of p-4E-BP1 and of Notch-1; lower cytoplasmic expression of p85αPI3K, p-p70S6K and p-ERK1/2; and lower PTEN Histo-scores (H-scores). PTEN H-score was inversely correlated with recurrence probability. In univariate survival analysis, nuclear expression of p-4E-BP1 and absence of p-ERK1/2 expression portended adverse prognosis, whereas in multivariate survival analysis, p-ERK1/2 expression emerged as an independent favourable prognostic factor. Treatment of the human meningioma cell line HBL-52 with the PI3K inhibitor LY294002 resulted in reduction of p-AKT, p-p70S6K and p-ERK1/2 protein levels. The complex interactions established between components of the PI3K/AKT/mTOR pathway, or with components of the MAPK, JAK/STAT and Notch-1 pathways, appear to be essential for facilitating and fuelling meningioma progression.