Lypopolysaccharide Research Articles

Melatonin receptor agonist ramelteon alleviates experimental acute ocular inflammation via HIF-1Α/VEGF/E-NOS signaling.

Ramelteon (RML) is a potent, selective agonist of the high-affinity melatonin receptor 1 and 2 receptors. In addition, RML is known to have antioxidant and anti-inflammatory effects. In this study, we aimed to investigate the effects of RML on HIF-1α, VEGF and e-NOS signaling pathway in a rat model of endotoxin-induced uveitis (EIU). Twenty-eight Wistar albino rats were divided into 4 groups as controls, lypopolysaccharide (LPS) group (5 mg/kg i.p.), LPS + RML group (5 mg/kg i.p and 8 mg/kg orally, respectively) and RML group (8 mg/kg orally). EIU was induced by a single intraperitoneal LPS injection. Histopathological and genetical analyses were performed. In histopathological analysis, LPS caused mild anterior uveitis characterized by increased surface area of iris leaflets and ciliary body due to edema, mild to moderate congestion, and inflammatory infiltrate 6 h following the injection. The pathological findings were reduced by RML. Higher inflammation levels seen in LPS group were significantly reduced in LPS + RML group. Also, HIF-1 α, eNOS and VEGF expressions increased in LPS and decreased in LPS + RML group. RML treatment reversed the changes in the HIF-1α /eNOS/ VEGF signaling pathway in LPS-induced uveitis in rats, preventing the progression of the damage and showed positive effects.

The Anti-Inflammatory Effect of Nanoarchaeosomes on Human Endothelial Cells.

Archaebacterias are considered a unique source of novel biomaterials of interest for nanomedicine. In this perspective, the effects of nanoarchaeosomes (ARC), which are nanovesicles prepared from polar lipids extracted from the extreme halophilic Halorubrum tebenquinchense, on human umbilical vein endothelial cells (HUVEC) were investigated in physiological and under inflammatory static conditions. Upon incubation, ARC (170 nm mean size, −41 mV ζ) did not affect viability, cell proliferation, and expression of intercellular adhesion molecule-1 (ICAM-1) and E-selectin under basal conditions, but reduced expression of both molecules and secretion of IL-6 induced by lypopolysaccharide (LPS), Pam3CSK4 or Escherichia coli. Such effects were not observed with TNF-α or IL-1β stimulation. Interestingly, ARC significantly decreased basal levels of von Willebrand factor (vWF) and levels induced by all stimuli. None of these parameters was altered by liposomes of hydrogenated phosphatidylcholine and cholesterol of comparable size and concentration. Only ARC were endocytosed by HUVEC and reduced mRNA expression of ICAM-1 and vWF via NF-ĸB and ERK1/2 in LPS-stimulated cells. This is the first report of the anti-inflammatory effect of ARC on endothelial cells and our data suggest that its future use in vascular disease may hopefully be of particular interest.

Acute-Phase Immune Response Involves Fever, Sickness Behavior, and an Elevated Metabolic Rate in the Subterranean Rodent Ctenomys talarum.

AbstractThe acute-phase response (APR) is an induced innate response and may involve pronounced physiological and behavioral changes. One of the most common assays to study the APR involves the use of a lypopolysaccharide (LPS) from the cell wall of gram-negative bacteria. In this study, we determined the energetic costs of the APR in the subterranean rodent Ctenomys talarum, as well as the effects of the exposure to LPS on body temperature, body mass loss, and behavior in this species. Furthermore, we monitored levels of circulating endotoxin after LPS exposure. Our results suggest that in C. talarum, the APR is energetically costly, resulting in a 14% increase in metabolic rate. Animals exposed to LPS experienced a short-term thermal response, weight loss, and changes in their behavior that included more time spent resting and with their eyes totally or partially closed. However, the magnitude of the effects of LPS exposure varied between sexes and among animals. Also, there was a clear peak in circulating endotoxin levels in plasma 3 h postinjection (hpi) and a significant decrease of these levels 24 hpi, but peak endotoxin concentration values recorded were highly variable among animals. In light of these results, ecological determinants of immune function variation in tuco-tucos are discussed considering the roles of pace of life, habitat, and degree of pathogen exposure in these subterranean rodents.

Automated Emotion Classification in Free-moving Rats

Studies involving emotion often use animal models and currently rely on manual labelling by researchers. This human-driven labelling approach leads to a number of challenges such as: long analysis times, imprecise results, observer drift, and varying correlation between observers. These problems impact reproducibility, and have contributed to our lack of understanding of fundamental mechanical questions such as how emotions arise from neuronal circuits. Recent success of machine learning models across similar problems show that it can help to mitigate these challenges while meeting or exceeding human accuracy. 
 We developed a classifier pipeline that takes in videos and produces an emotion label. The pipeline extracts body part positions from each frame using a pose estimator and feeds them into an Artificial Neural Network (ANN) classifier built using stacked Long Short Term Memory (LSTM) layers. The data was collected by treating nine rats with Lypopolysaccharide (LPS) injections (10mg/kg). First, rats were recorded for 10 minutes under control conditions with no manipulation and no observed symptoms of stress or malaise. A week later, rats were injected with LPS and filmed for 10 minutes two hours post-injection. 
 The classifier pipeline developed correctly labelled 78% of the 125,040 video segments from 8 test videos. When combined with a vote-based system, this led to 7 of the 8 test videos being classified correctly which was the same accuracy attained by a human expert from the lab. The test videos had varying environments and used rats that were different from the training videos, providing evidence of a degree of robustness in the model. Future work will focus on expanding the test data and incorporating models for 3D pose estimation and behavioral classification.

Lycopene has a protective effect on septic shock‑induced cardiac injury in rats.

The aim of the present study is to investigate the cardioprotective effect of lycopene, known for its antioxidant and anti-inflammatory effect, in a rat sepsis model induced by lypopolysaccharide (LPS). The oxidative stress parameters, antioxidant parameters and cytokine levels with or without lycopene treatment in LPS‑induced septic rats as well as in controls were measured in serum and tissue. Histologic examinations of the cardiac tissues were also performed. The Kruskal-Wallis and the Bonferroni-adjusted Mann-Whitney U Test was used for analysis. A p value < 0.05 was considered significant. The data of this study showed that lycopene pretreatment reduced the oxidative stres parametersand , proinflammatory cytokines as well as increased the antoxidant enzyme activities in both serum and cardiac tissues in LPS‑induced septic rats.. Moreover, hyperaemia and haemorrhage in the epicardium, myocardium and endocardium were lower in the lycopene pretreated group as compared to the LPS alone group. These results suggest that lycopene could be beneficial for the prevention of cardiac injury caused by sepsis through reducing the cytokine levels and oxidative stress parameters (Tab. 4, Fig. 1, Ref. 35).

Aniseed (Pimpinella anisum L.) essential oil reduces pro-inflammatory cytokines and stimulates mucus secretion in primary airway bronchial and tracheal epithelial cell lines

Aniseed (Pimpinella anisum L., Apiaceae) is a medicinal and aromatic plant widely cultivated in the Mediterranean area and used in foodstuffs, as ingredient of famous liqueurs, confectionery and bakery products. Its essential oil is one of the most selled on the market and used on an industrial level. In addition, aniseed is exploited as an herbal remedy to threat respiratory disorders. However, little information is available about its effect on respiratory tissues during inflammation. In the present work, we evaluated the anti-inflammatory activity and the effect on mucin secretion of aniseed essential oil in primary airway bronchial and tracheal epithelial cells (HBEpC and HTEpC, respectively) in a model of lung inflammation induced by lypopolysaccharide (LPS). The aniseed essential oil was obtained by hydrodistillation of the fruits from plants cultivated in central Italy, and analysed by gas chromatography-mass spectrometry (GC–MS). HBEpC and HTEpC lines were treated with LPS and then incubated with 0.3% of aniseed essential oil. Levels of pro-inflammatory cytokines, IL-8 and IL-1 beta were assessed by RT/PCR and Western Blot analysis. Muc5ac protein release was determined in culture medium of HBEpC- and HTEpC- LPS-treated lines by Western Blot analysis. Aniseed essential oil showed a very high level of (E)-anethole (97.9%). At non-toxic doses, it significantly decreased the expression levels of IL-1 and IL-8 and increased the Muc5ac secretion in LPS-treated HBEpC and HTEpC lines. These results provide new evidence supporting the ethnobotanical use of aniseed in the treatment of respiratory diseases. In particular, aniseed essential oil showed a significant anti-inflammatory effect on both HBEpC and HTEpC cells together with mucus hypersecretion.

Extracellular Hsp70 induces inflammation and modulates LPS/LTA-stimulated inflammatory response in THP-1 cells

Extracellular Hsp70 (eHsp70) can act as damage-associated molecular pattern (DAMP) via Toll-like receptors TLR2 and TLR4, and stimulate immune and inflammatory responses leading to sterile inflammation and propagation of already existing inflammation. It was found elevated in the blood of patients with chronic obstructive pulmonary disease (COPD), who might suffer occasional bacterial colonizations and infections. We used a monocytic THP-1 cell line as a cellular model of systemic compartment of COPD to assess inflammatory effects of eHsp70 when present alone or together with bacterial products lypopolysaccharide (LPS) and lypoteichoic acid (LTA). THP-1 cells were differentiated into macrophage-like cells and treated with various concentrations of recombinant human Hsp70 protein (rhHsp70), LPS (TLR4 agonist), LTA (TLR2 agonist), and their combinations for 4, 12, 24, and 48h. Concentrations of IL-1α, IL-6, IL-8, and TNF-α were determined by ELISA. Cell viability was assessed by MTS assay, and mode of cell death by luminometric measurements of caspases-3/7, -8, and -9 activities. rhHsp70 showed cell protecting effect by suppressing caspases-3/7 activation, while LPS provoked cytotoxicity through caspases-8 and -3/7 pathway. Regarding inflammatory processes, rhHsp70 alone induced secretion of IL-1α and IL-8, but had modulatory effects on release of all four cytokines when applied together with LPS or LTA. Combined effect with LPS was mainly synergistic, and with LTA mainly antagonistic, although it was cytokine- and time-dependent. Our results confirmed pro-inflammatory function of extracellular Hsp70, and suggest its possible implication in COPD exacerbations caused by bacterial infection through desensitization or inappropriate activation of TLR2 and TLR4 receptors.

A natural xanthone increases catalase activity but decreases NF-kappa B and lipid peroxidation in U-937 and HepG2 cell lines

Mangiferin, a C-glycosyl xanthone, has shown anti-inflammatory, antioxidant, and anti-tumorigenic activities. In the present study, we investigated the molecular mechanism for the antioxidant property of mangiferin. Considering the role of nuclear transcription factor kappa B (NF-κB) in inflammation and tumorigenesis, we hypothesized that modulating its activity will be a viable therapeutic target in regulating the redox-sensitive ailments. Our results show that mangiferin blocks several inducers, such as tumor necrosis factor (TNF), lypopolysaccharide (LPS), phorbol-12-myristate-13-acetate (PMA) or hydrogen peroxide (H2O2) mediated NF-κB activation via inhibition of reactive oxygen species generation. In silico docking studies predicted strong binding energy of mangiferin to the active site of catalase (−9.13kcal/mol), but not with other oxidases such as myeloperoxidase, glutathione peroxidase, or inducible nitric oxide synthase. Mangiferin increased activity of catalase by 44%, but had no effect on myeloperoxidase activity in vitro. Fluorescence spectroscopy further revealed the binding of mangiferin to catalase at the single site with binding constant and binding affinity of 3.1×10−7M−1 and 1.046 respectively. Mangiferin also inhibits TNF-induced lipid peroxidation and thereby protects apoptosis. Hence, mangiferin with its ability to inhibit NF-κB and increase the catalase activity may prove to be a potent therapeutic.

Standardizing placenta processing procedures across a multi-site network through the creation of a certification and quality control program

Standardizing placenta processing procedures across a multi-site network through the creation of a certification and quality control program

The Plesiomonas shigelloides wbO1 gene cluster and the role of O1-antigen LPS in pathogenicity

The Plesiomonas shigelloides 302-73 strain (serotype O1) wb gene cluster encodes 15 proteins which are consistent with the chemical structure of the O1-antigen lypopolysaccharide (LPS) previously described for this strain. The P. shigelloides O1-antigen LPS export uses the Wzy-dependent pathway as correspond to heteropolysaccharides structures. By the isolation of two mutants lacking this O1-antigen LPS, we could establish that the presence of the O1-antigen LPS is crucial for to survive in serum mainly to become resistant to complement. Also, it is an important factor in the bacterial adhesion and invasion to some eukaryotic cells, and in the ability to form biofilms. This is the first report on the genetics from a P. shigelloides O-antigen LPS cluster (wb) not shared by Shigella like P. shigelloides O17, the only one reported until now.

Associação de imunoestimulante com anti-helmíntico no tratamento da verminose em ovinos

Este estudo teve como objetivo verificar a eficiência do uso de imunoestimulante associado a anti-helmíntico no tratamento das helmintoses de ovinos. Os animais do grupo I (n=29) receberam o anti-helmíntico albendazole (11mg kg-1) em administração única e o imunoestimulante composto de Propionibacterium granulosum (16ug kg-1) e lipopolissacarídeo (LPS) de Escherichia coli (1,2ug kg-1) em duas doses com intervalo de 48 horas e os animais do grupo II (n=29) receberam o anti-helmíntico albendazole (11mg kg-1). Amostras foram colhidas semanalmente durante 28 dias para a realização da contagem total e diferencial de leucócitos, hematócrito e contagem de ovos por grama de fezes (OPG). Os animais que receberam imunoestimulante associado a anti-helmíntico apresentaram aumento significativo dos valores de eosinófilos e linfócitos (P&lt;0,05) em relação aos animais que receberam somente anti-helmíntico. Na contagem de ovos por grama de fezes (OPG), não foram observadas diferenças significativas entre os grupos (P&gt;0,05). Com base nesses resultados, pode-se concluir que imunoestimulantes podem ser utilizados associados a anti-helmínticos como alternativa terapêutica no tratamento das helmintíases em ovinos, uma vez que promovem a ativação da resposta imune com participação de células e mediadores importantes para a eliminação de helmintos em ovinos.

Clionosterol and Ethyl Cholestan-22-enol Isolated from the Rhizome of &lt;i&gt;Polygala tenuifolia&lt;/i&gt; Inhibit Phosphatidylinositol 3-Kinase/Akt Pathway

Phosphatidylinositol 3-kinase (PI3K)/Akt inhibitors were isolated from the rhizome of Polygala tenuifolia WILLD (PT, Polygalaceae), which has been used in traditional Chinese medicine for inflammation, dementia, amnesia, neurasthenia and cancer, by activity-guided fractionation. For the assay of PI3K/Akt pathway, cytoprotective Tat-transduced CHME5 cells, which are the cytoprotective phenotype against lypopolysaccharide (LPS)/cycloheximide (CHX), were used. We isolated 4 anti-cytoprotective compounds, clionasterol (1), ethyl cholestan-22-enol (2), 3-O-β-D-glucosyl ethyl cholestan-22-enol (3), and 3-O-β-D-glucopyranosyl clionasterol (4) from EtOAc fraction of PT against Tat-transduced CHME5 cells. Of them, (1) and (2) most potently abolished cytoprotective effect of Tat-transduced CHME5 cells. These constituents (1) and (2) inhibited the activation of 3-phosphoinositide-dependent kinase 1 (PDK1) and its downstream molecules, Akt/glycogen synthase kinase (GSK)3β, in PI3K/Akt cell survival signaling pathway, but did not suppress the activation of PI3K. Based on these finding, (1) and (2) may abolish the cytoprotective phenotype of Tat-transduced CHME5 cells by inhibiting PDK1 phosphorylation in PI3K/Akt pathway.

In Vitro Downregulation of Matrix Metalloproteinase-9 in Rat Glial Cells by CCR5 Antagonist Maraviroc: Therapeutic Implication for HIV Brain Infection

BackgroundMatrix metalloproteinases (MMPs) released by glial cells are important mediators of neuroinflammation and neurologic damage in HIV infection. The use of antiretroviral drugs able to combat the detrimental effect of chronic inflammation and target the exaggerated MMP activity might represent an attractive therapeutic challenge. Recent studies suggest that CCR5 antagonist maraviroc (MVC) exerts immunomodulant and anti-inflammatory activity beyond its anti-HIV properties. We investigated the in vitro effect of MVC on the activity of MMPs in astrocyte and microglia cultures.Methodology/Principal FindingsPrimary cultures of rat astrocytes and microglia were activated by exposure to phorbol myristate acetate (PMA) or lypopolysaccharide (LPS) and treated in vitro with MVC. Culture supernatants were subjected to gelatin zymography and quantitative determination of MMP-9 and MMP-2 was done by computerized scanning densitometry. MMP-9 levels were significantly elevated in culture supernatants from both LPS- and PMA-activated astrocytes and microglia in comparison to controls. The treatment with MVC significantly inhibited in a dose-dependent manner the levels and expression of MMP-9 in PMA-activated astrocytes (p<0,05) and, to a lesser extent, in PMA-activated microglia. By contrast, levels of MMP-2 did not significantly change, although a tendency to decrease was seen in PMA-activated astrocytes after treatment with MVC. The inhibition of levels and expression of MMP-9 in PMA-activated glial cells did not depend on cytotoxic effects of MVC. No inhibition of MMP-9 and MMP-2 were found in both LPS-activated astrocytes and microglia.ConclusionsThe present in vitro study suggests that CCR5 antagonist compounds, through their ability to inhibit MMP-9 expression and levels, might have a great potential for the treatment of HIV-associated neurologic damage.

The effects of bifidobacterial secretory adhesin on the stress response of intestinal epithelial cells

Objective To observe the effects of bifidobacterial sectory adhesin on NF-κB DNA binding activity,cytoplasm IκB,nuclei NF-κBp65,TNF-α,IL-1β,and IL-8 expression in intestinal epithelial cell post stress response.Methods The cultured intestinal epithelial cell line Lovo cells were divided into 5 groups,which included directly stimulated by lypopolysaccharide (LPS) (100 ng/ml) or H2O2 (200 μmol/L) for 3 hours groups,bifidobacterial sectory adhesin (30μg/ml) pre-incubation for 30 minutes and then treated by LPS (100 ng/ml) or H2O2 (200 μmol/L) for 3 hours groups and control group with no treatment.NF-κB DNA binding activity was evaluated by electrophoretic mobility shift assay (EMSA).The cytoplasm IκB and nuclei NF-κBp65 expression were determined by Western blot.The expressions of TNF-α,IL-1β and IL-8 at mRNA level were detected by semi-quantatitive assay of RT-PCR.Results The expressions of NF-κB DNA binding activity [(6.20±0.35) times and (4.16 ± 0.52) times of that of non treated control group,respectively] and nuclei NF-κBp65 [ (0.64±0.05) and (0.67±0.06)] were higher in cells after LPS or H2()2 stimulated,however the cytoplasm IκB expression [ (0.28 ± 0.10) and (0.39 ± 0.12) respectively] was weaker.After bifidobacterial sectory adhesin pre-incubation,the expressions of NF-κB DNA binding activity and nuclei NF-κBp65decreased obviously,but cytoplasm IκB expression increased.After treated with LPS or H2O2,the mRNA expressions of TNF-α,IL-1β and IL-8 were significantly increased [LPS treated group2 (0.92±0.10)、(0.38±0.03)、(1.44±0.25),H2O2 treated group:(0.89±0.13)、(0.36±0.06)、(1.42±0.18)].After bifidobacterial sectory adhesin pre-incubation,their expressions decreased.The mRNA expressions of TNF-α,IL-1β and IL-8 have significantly positive correlation with NF-κB DNA binding activity.Conclusions There is a significant inhibition role of bifidobacterial sectory adhesin in LPS and H2O2 induced NF-κB DNA binding activity in intestinal epithelia cells.The activation of NFκB may associate with the regulation of TNF-α,IL-1β and IL-8 proinflammatory cytokines expression. Key words: Bifidobacterium; Cell adhesion; Tumor cells, cultured; Intestines; Lipopolysaccharides; Hydrogen peroxide; Nuclear factor-κB; Cytokines

Dydrogesterone exerts endothelial anti-inflammatory actions decreasing expression of leukocyte adhesion molecules

Clinical observations and basic studies show that progesterone and progestins have a variable influence on endothelial function. Dydrogesterone (DG) is a widely used progestin, but its endothelial actions have not been thoroughly assessed. In this study, we investigated the effects of DG and its metabolite 20-α-dihydro-dydrogesterone (DHD), natural progesterone as well as medroxyprogesterone acetate, on the expression of leukocyte adhesion molecules in human endothelial cells using an in vitro experimental endothelial inflammation system. Our findings show that all progestins significantly suppress endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and inter-cellular adhesion molecule-1 (ICAM-1) induced by bacterial lypopolysaccharide (LPS). These inhibitory effects of DG and DHD require activation of progesterone receptor. DG and DHD decrease adhesion molecule expression associated with LPS administration by preventing nuclear translocation of the pro-inflammatory transcription factor nuclear factor-κB. In addition, DG and DHD do not alter the anti-inflammatory effects of 17β-estradiol. In conclusion, DG and DHD decrease endothelial inflammatory responses induced by LPS, via reduced expression of the pro-atherogenic adhesion molecules VCAM-1 and ICAM-1. These actions may be relevant for the vascular effects of DG.

Antidepressants, but not antipsychotics, modulate GR function in human whole blood: An insight into molecular mechanisms

Clinical studies have demonstrated an impairment of glucocorticoid receptor (GR)-mediated negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis in patients with major depression (GR resistance), and its resolution by antidepressant treatment. Recently, we showed that this impairment is indeed due to a dysfunction of GR in depressed patients (Carvalho et al., 2009), and that the ability of the antidepressant clomipramine to decrease GR function in peripheral blood cells is impaired in patients with major depression who are clinically resistant to treatment (Carvalho et al. 2008). To further investigate the effect of antidepressants on GR function in humans, we have compared the effect of the antidepressants clomipramine, amytriptiline, sertraline, paroxetine and venlafaxine, and of the antipsychotics, haloperidol and risperidone, on GR function in peripheral blood cells from healthy volunteers (n=33). GR function was measured by glucocorticoid inhibition of lypopolysaccharide (LPS)-stimulated interleukin-6 (IL-6) levels. Compared to vehicle-treated cells, all antidepressants inhibited dexamethasone (DEX, 10-100nM) inhibition of LPS-stimulated IL-6 levels (p values ranging from 0.007 to 0.1). This effect was specific to antidepressants, as antipsychotics had no effect on DEX-inhibition of LPS-stimulated IL-6 levels. The phosphodiesterase (PDE) type 4 inhibitor, rolipram, potentiated the effect of antidepressants on GR function, while the GR antagonist, RU-486, inhibited the effect of antidepressants on GR function. These findings indicate that the effect of antidepressants on GR function are specific for this class of psychotropic drugs, and involve second messenger pathways relevant to GR function and inflammation. Furthermore, it also points towards a possible mechanism by which one maybe able to overcome treatment-resistant depression. Research in this field will lead to new insights into the pathophysiology and treatment of affective disorders.

Ability of Goat Milk to Modulate Healthy Human Peripheral Blood Lymphomonocyte and Polymorphonuclear Cell Function: In vitro Effects and Clinical Implications

The in vitro effects of goat's milk from different sources (Jonica, Saanen, and Priska breeds plus a commercial preparation) on healthy human peripheral blood mononuclear cells (PBMCs) were evaluated in terms of nitric oxide (NO) and cytokine release. According to the incubation time (24 h or 48 h) used all milks could induce release of NO from monocytes. In this context, however, in the presence of a commercial milk preparation inhibition of lypopolysaccharide (LPS)-induce NO generation was evident. Also polymorphonuclear cells stimulated with the various milks released detectable amounts of NO. In the case of Priska milk inhibition of LPS-mediated NO generation was observed. Despite a broad array of cytokines tested [Interleukin (IL)-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17, Tumor Necrosis Factor (TNF)-alpha, Transforming Growth Factor-beta and Granulocyte Colony Stimulating Factor] only IL-10, TNF-alpha, and IL-6 were released by PBMCs upon stimulation with various milks. Taken together, these data indicate that goat's milk for its capacity to produce NO may exert a cardioprotective and anti-atherogenic effect in consumers. Moreover, induction of proinflammatory (TNF-alpha and IL-6) and anti-inflammatory (IL-10) cytokines suggests the ability of this milk to maintain immune homeostasis in the immunocompromised host (e.g., aged people).

Sphingomyelinase dependent apoptosis of dendritic cells following treatment with amyloid peptides

Amyloid peptides are formed during inflammation and modify the function of immune cells. The present study explored the effect of amyloid β-peptide (Aβ 1–42) and islet amyloid polypeptide (IAPP) on bone marrow derived dendritic cells (DCs). DCs were treated with Aβ 1–42 or IAPP with subsequent assessment of ceramide formation, caspase 8 and 3 activity, DNA fragmentation and phosphatidylserine exposure. In addition, TNFα secretion was assessed in lypopolysaccharide (LPS)-stimulated Aβ 1–42- or IAPP-treated DCs. Within 24 h Aβ 1–42 and IAPP triggered ceramide formation, caspase 8 and caspase 3 activation, DNA fragmentation and annexin V binding in DCs obtained from wild type mice, whereas in DCs from sphingomyelinase deficient ( asm −/− ) mice and in wild type DCs treated with sphingomyelinase inhibitor amitriptyline all these effects were strongly impaired. Moreover, ceramide formation was also reduced in wild type DCs in which acid sphingomyelinase (Asm) was silenced with Asm-targeted siRNA. Finally, Aβ 1–42 and IAPP treatment was further followed by a decline of TNFα formation in wild type DCs. In conclusion, amyloid peptides induce DC apoptosis presumably through activation of acid sphingomyelinase resulting in production of ceramide.

Anti-inflammatory and analgesic activity of a novel inhibitor of microsomal prostaglandin E synthase-1 expression

In a previous study, we reported a new γ-hydroxybutenolide derivative, 4-benzo[ b]thiophen-2-yl-3-bromo-5-hydroxy-5 H-furan-2-one (BTH), as inhibitor of microsomal prostaglandin E synthase-1 (mPGES-1) expression in lypopolysaccharide (LPS) stimulated RAW 264.7 and TPH-1 cells, without affecting cyclooxygenase-2 (COX-2). In this study, we evaluated the in vivo effect of BTH on some acute and chronic inflammatory animal models in relation to its inhibitory profile on mPGES-1 expression. In the zymosan-induced mouse air pouch model, BTH produced a dose-dependent inhibition of prostaglandin E 2 (PGE 2) production and mPGES-1 protein expression in pouch exudates without any effect on COX-2 protein expression. This behavior was confirmed in the chronic model of collagen-induced arthritis, where administration of BTH (5 mg/kg) clearly reduced PGE 2 and mPGES-1 expression in joint tissues, whereas COX-2 was unaffected. These effects were accompanied by the suppression of clinical and histopathological manifestations of disease such as the loss of proteoglycan, and the destruction of surface cartilage. Other enzymes participating in the metabolism of arachidonic acid, such as prostaglandin I 2 synthase, tromboxane A 2 synthase or 5-lipoxygenase were unaffected by this compound. The acetic acid-induced hyperalgesia model in LPS-sensitized mice showed a dose-dependent analgesic effect of BTH, exerting an ED 50 value of 6.2 mg/kg. Our data suggest that inhibition of mPGES-1 protein expression in acute and chronic inflammatory models by BTH, could provide a potential therapeutic target and a pharmacological tool to discern the role of the inducible enzymes COX-2 and mPGES-1 in inflammatory pathologies.

Evaluation of TH1/TH2 Lymphocyte Balance and Lypopolysaccharide Receptor Expression in Asthma Patients

Introduction: An increase in the number of asthma patients which has recently been observed depends on their place of residence and their occupation. This suggests that both external factors and genetic predispositions affect the development of the disease. The contact with bacterial lypopolysaccharide (LPS) may suppress the development of asthma among rural inhabitants. The mechanism of LPS effect most probably consists in the activation of macrophages and granulocytes by TLR4 and CD14 receptors for the production of cytokines, which affect Th1/Th2 balance. The objective of the study was the evaluation of CD14 and TLR4 expression on mononuclear cells and the analysis of Th1/Th2 balance in peripheral blood among asthma patients. Material and Methods: The study group covered 22 patients with bronchial asthma (mean age 45 ± 15), and was conducted by the method of flow cytometry with the use of fluorochrome-labelled monoclonal antibodies. CD14 and TLR expression was assessed in peripheral blood monocytes. Th1/Th2 balance was determined by the measurement of intracellular IL-2, IFN-γ, IL-4 and IL-10 expression in T-helper cells after culture with the stimulation of cytokine production. Results: A negative correlation was noted between TLR4 expression and the percentage of Th2 lymphocytes, while a positive correlation was observed between expression of TLR4 and percentage of Th1 cells. No relationship was found between CD14 expression on monocytes and the percentage of Th1 and Th2 lymphocytes. Conclusions: An increased percentage of lymphocytes with TLR4 expression is associated with the change in Th1/Th2 balance in favour of Th1 lymphocytes in asthma patients.