Cell-type specific anti-cancerous effects of nitro-oleic acid and its combination with gamma irradiation.

Nitro-fatty acids (NFAs) are endogenous lipid mediators capable of post-translational modifications of selected regulatory proteins. Here, we investigated the anti-cancerous effects of nitro-oleic acid (NO2OA) and its combination with gamma irradiation on different cancer cell lines. The effects of NO2OA on cell death, cell cycle distribution, or expression of p21 and cyclin D1 proteins were analyzed in cancer (A-549, HT-29 and FaDu) or normal cell lines (HGF, HFF-1). Dose enhancement ratio at 50 % survival fraction (DERIC50) was calculated for samples pre-treated with NO2OA followed by gamma irradiation. NO2OA suppressed viability and induced apoptotic cell death. These effects were cell line specific but not in general selective for cancer cells. HT-29 cell line exerted higher sensitivity toward NO2OA treatment among cancer cell lines tested: induction of cell cycle arrest in the G2/M phase was associated with an increase in p21 and a decrease in cyclin D1 expression. Pre-treatment of HT-29 cells with NO2OA prior irradiation showed a significantly increased DERIC50, demonstrating radiosensitizing effects. In conclusion, NO2OA exhibited potential for combined chemoradiotherapy. Our results encourage the development of new NFAs with improved features for cancer chemoradiation.

Nitro-Oleic Acid Inhibits Stemness Maintenance and Enhances Neural Differentiation of Mouse Embryonic Stem Cells via STAT3 Signaling.

Nitro-oleic acid (NO2-OA), pluripotent cell-signaling mediator, was recently described as a modulator of the signal transducer and activator of transcription 3 (STAT3) activity. In our study, we discovered new aspects of NO2-OA involvement in the regulation of stem cell pluripotency and differentiation. Murine embryonic stem cells (mESC) or mESC-derived embryoid bodies (EBs) were exposed to NO2-OA or oleic acid (OA) for selected time periods. Our results showed that NO2-OA but not OA caused the loss of pluripotency of mESC cultivated in leukemia inhibitory factor (LIF) rich medium via the decrease of pluripotency markers (NANOG, sex-determining region Y-box 1 transcription factor (SOX2), and octamer-binding transcription factor 4 (OCT4)). The effects of NO2-OA on mESC correlated with reduced phosphorylation of STAT3. Subsequent differentiation led to an increase of the ectodermal marker orthodenticle homolog 2 (Otx2). Similarly, treatment of mESC-derived EBs by NO2-OA resulted in the up-regulation of both neural markers Nestin and ß-Tubulin class III (Tubb3). Interestingly, the expression of cardiac-specific genes and beating of EBs were significantly decreased. In conclusion, NO2-OA is able to modulate pluripotency of mESC via the regulation of STAT3 phosphorylation. Further, it attenuates cardiac differentiation on the one hand, and on the other hand, it directs mESC into neural fate.

5-Nitro-2,4-Dichloropyrimidine as an Universal Model for Low-Energy Electron Processes Relevant for Radiosensitization.

We report experimental results of low-energy electron interactions with.

How to measure the immunosuppressive activity of MDSC: assays, problems and potential solutions.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of mononuclear and polymorphonuclear myeloid cells, which are present at very low numbers in healthy subjects, but can expand substantially under disease conditions. Depending on disease type and stage, MDSC comprise varying amounts of immature and mature differentiation stages of myeloid cells. Validated unique phenotypic markers for MDSC are still lacking. Therefore, the functional analysis of these cells is of central importance for their identification and characterization. Various disease-promoting and immunosuppressive functions of MDSC are reported in the literature. Among those, the capacity to modulate the activity of T cells is by far the most often used and best-established read-out system. In this review, we critically evaluate the assays available for the functional analysis of human and murine MDSC under in vitro and in vivo conditions. We also discuss critical issues and controls associated with those assays. We aim at providing suggestions and recommendations useful for the contemporary biological characterization of MDSC.

A Concise Synthesis of Forskolin.

A 24-step synthesis of (±)-forskolin is presented, which delivered hundred milligram quantities of this complex diterpene in one pass. Transformations key to our approach include: a) a strategic allylic transposition, b) stepwise assembly of a sterically encumbered isoxazole ring, and c) citric acid-modified Upjohn dihydroxylation of a resilient tetrasubstituted olefin. The developed route has exciting potential for the preparation of new forskolin analogues inaccessible by semisynthesis.

Molecular pharmacology of antihistamines in inhibition of oxidative burst of professional phagocytes.

Antihistamines of the H1and H3/H4groups interfere with oxidative burst of human professional phagocytes in vitro. In the concentration of 10 µM, H1antihistamines of the 1st and 2nd generation inhibited oxidative burst of human neutrophils in the rank order of potency: dithiaden > loratadine > brompheniramine > chlorpheniramine > pheniramine. Of the H1antihistamines, the most effective was dithiaden in suppressing oxidative burst of whole human blood and dose-dependently the chemiluminescence of isolated neutrophils at extra- and intracellular level. Inhibition of free oxygen radical generation in isolated neutrophils by dithiaden resulted from the inhibition of protein kinase C activation. The potentiation of recombinant caspase-3 by dithiaden is supportive of the antiinflammatory effect of dithiaden and suggestive of increasing the apoptosis of professional phagocytes. Of the H3/H4antihistamines, the most effective was JNJ7777120 in decreasing chemiluminescence in whole blood and also at extra- and intracellular sites of isolated neutrophils. JNJ 10191584 and thioperamide were less effective and the latter significantly potentiated free oxygen radical generation intracellularly. The results demonstrated that, compared with the H3/H4antihistamines investigated, H1antihistamines were much more potent in inhibiting free oxygen radical generation in human professional phagocytes. This finding should be taken into account therapeutically.

The natural stilbenoid pinosylvin and activated neutrophils: effects on oxidative burst, protein kinase C, apoptosis and efficiency in adjuvant arthritis.

AIM: To investigate the effects of the naturally occurring stilbenoid pinosylvin on neutrophil activity in vitro and in experimental arthritis, and to examine whether protein kinase C (PKC) activation served as an assumed target of pinosylvin action. METHODS: Fresh human blood neutrophils were isolated. The oxidative burst of neutrophils was evaluated on the basis of enhanced chemiluminescence. Neutrophil viability was evaluated with flow cytometry, and PKC phosphorylation was assessed by Western blotting analysis. Adjuvant arthritis was induced in Lewis rats with heat-killed Mycobacterium butyricum, and the animals were administered with pinosylvin (30 mg/kg, po) daily for 21 d after arthritis induction. RESULTS: In isolated human neutrophils, pinosylvin (10 and 100 µmol/L) significantly decreased the formation of oxidants, both extra- and intracellularly, and effectively inhibited PKC activation stimulated by phorbol myristate acetate (0.05 µmol/L). The inhibition was not due to neutrophil damage or increased apoptosis. In arthritic rats, the number of neutrophils in blood was dramatically increased, and whole blood chemiluminescence (spontaneous and PMA-stimulated) was markedly enhanced. Pinosylvin administration decreased the number of neutrophils (from 69 671 ± 5588/µL to 51 293 ± 3947/µL, P=0.0198) and significantly reduced the amount of reactive oxygen species in blood. CONCLUSION: Pinosylvin is an effective inhibitor of neutrophil activity, and is potentially useful as a complementary medicine in states associated with persistent inflammation.

Free-radical degradation of high-molar-mass hyaluronan induced by Weissberger's oxidative system: potential antioxidative effect of bucillamine.

OBJECTIVES: Hyaluronan (HA), one of the main components of extracellular matrix, is a glycosaminoglycan composed of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid linked by ß-(1→4) and ß-(1→3) glycoside bonds. High-molar-mass HA was used as a model for studying its oxidative degradation. In the present paper protective effects of bucillamine against the free-radical degradation of HA were investigated. The HA fragments generated were characterized as well. METHODS: To induce free-radical-mediated degradation of high-molar-mass HA under aerobic conditions, we applied Weissberger's oxidative system, comprising biogenic compounds in relevant pathophysiological concentrations, i.e. 100 µM ascorbate plus 1 µM Cu(II). Time-dependent decreases of dynamic viscosity of the HA solutions were recorded by rotational viscometry. Electron donor behaviors of bucillamine were studied by a standard ABTS test method and a chemiluminescence (CL) assay. Ability of incorporation of generated bucillamine thiyl radicals into the biopolymer was verified by Fourier-transform infrared spectroscopy (FT-IR) and size exclusion chromatography with a multi-angle light scattering photometer (SEC-MALS). RESULTS: Decrease of HA viscosity reflected HA degradation. The drug tested was applied in two arrangements: to prevent •OH radical generation (1) and ROO• type radicals propagation (2). Bucillamine, which acted as an efficient •H donor, is also a proper electron donor, as proved by ABTS and CL assays. FT-IR and SEC-MALS methods showed that the drug tested did not incorporate into the biopolymer chains. CONCLUSION: Bucillamine significantly protected high-molar-mass HA against free-radical degradation in vitro, and supposedly this positive action of the drug may be involved in its beneficial effect observed in clinical practice.

Administration of nitro-oleic acid mitigates radiation-induced hematopoietic injury in mice.

AIMS: Limited number of agents that provide protection against hematopoietic acute radiation syndrome led us to the evaluation of nitro-oleic acid (NO2OA) as a potential protector/mitigator against radiation-induced hematopoietic injury in C57/BL6 mice. MATERIALS AND METHODS: NO2OA was administered before and after sub-lethal total body irradiation (TBI) and hematological parameters were evaluated 3 or 7 days after TBI. KEY FINDINGS: Our results show that NO2OA significantly increase bone marrow cellularity including the granulocyte-macrophage colony-forming cells and erythroid progenitors on the 3rd day after TBI. In addition, NO2OA enhanced recovery of white blood cells (lymphocytes, neutrophils, and monocytes) in peripheral blood 7 days after irradiation. These effects may be in part attributed to NO2OA-induced granulocyte colony-stimulating factor production after TBI. On the other hand, radiation-induced impairment of peripheral red blood cells, hemoglobin, and platelets were not affected with NO2OA treatment up to 7 days post TBI. SIGNIFICANCE: In conclusion, our data show that NO2OA significantly protects hematopoiesis after irradiation, and thus showed a high potential to act as an agent for medical radiation countermeasure.

Analysis of hematological parameters in rheumatoid arthritis patients receiving biological therapy: contribution to prevention of avoidable hematological complications.

Administration of biological therapy (BT) in rheumatoid arthritis (RA) patients is often associated with hematological complications, which result in switching among therapies. Thus, there is an instant need for suitable screening parameters that will help to individualize the therapy and minimize the onset of adverse effects. We analyzed the hematological profile of 99 RA patients receiving TNFα (Adalimumab - ADA, Golimumab - GOL, Etanercept - ETA) or IL-6 receptor (Tocilizumab - TCZ) inhibitors in order to find possible indicators to improve personalization of RA therapy. BTs significantly affect the levels of observed hematological parameters. In contrast to TNF-α inhibitors, TCZ normalized almost all monitored hematological parameters to values of healthy donors. Only GOL from the TNF-α inhibitors studied, was able to normalize neutrophil counts, as well as platelet indicators. Importantly, effects on the blood parameters (e.g. lymphocytes or platelet count) differ even within the same therapeutic group (anti-TNFα). Variable effects of individual biological agents in RA treatment point to importance to evaluate the patient's hematological profile to improve the selection of suitable BT. It will help to personalize the administration of BT and prevent unnecessary switching from an effective therapy just because of provocation of avoidable hematological complications.

Suppression of oxidative burst in human neutrophils with the naturally occurring serotonin derivative isomer from Leuzea carthamoides.

OBJECTIVE: Neutrophil leukocytes and macrophages represent professional phagocytic cells. When appropriately stimulated, they undergo dramatic physiological and biochemical changes resulting in phagocytosis, chemotaxis and degranulation with the activation of reactive oxygen species (ROS) production known as the respiratory burst. DESIGN: In this study we analysed the effect of a crystalline complex fraction of four N-feruloyl-serotonin isomers isolated from the seeds of Leuzea carthamoides on the mechanism of oxidative burst of human neutrophils in vitro. RESULTS: N-feruloyl-serotonin (N-f-5HT) inhibited dose-dependently oxidative burst of human whole blood and isolated neutrophils in vitro stimulated with phorbol-myristate-acetate (PMA) as measured by luminol/isoluminol enhanced chemiluminescence.In isolated neutrophils stimulated with PMA, N-f-5HT was effective against extracellular as well as intracellular reactive oxygen species. Western blot analysis documented that N-f-5HT in concentrations of 10 and 100 µM significantly decreased PMA-induced phosphorylation of protein kinase C alpha/beta II. CONCLUSION: The results suggest that N-f-5HT represents an effective naturally occurring substance with potent effect on the oxidative burst of human neutrophils and could be further investigated for its pharmacological activity against oxidative stress in ischaemia-reperfusion, inflammation and other pathological conditions.

Molecular targets of the natural antioxidant pterostilbene: effect on protein kinase C, caspase-3 and apoptosis in human neutrophils in vitro.

OBJECTIVE: Pterostilbene, a naturally occurring phenolic derivative, exhibits various pharmacological effects, e.g. anti-cancerous, antioxidant, anti-inflammatory and anti-diabetic. Based on our previous study, we assessed the cellular and molecular effects of pterostilbene on human neutrophils and in cell free systems. Experimental and theoretical molecular descriptors of stilbene derivatives were also determined. METHODS: We assessed the antioxidant properties of pterostilbene using cell free system and computational methods. The effect of pterostilbene on protein kinase C activation/phosphorylation was detected by special anti-phospho protein kinase C antibodies. Membrane associated changes determining the life span of neutrophils and human recombinant caspase-3 assay were examined. RESULTS: Pterostilbene possessed comparable antioxidant properties as resveratrol in cell free system. Computational methods were used to establish the molecular characteristics of stilbene derivatives. The values of electronic parameters suggest a slight enhancement of electron donor properties of pterostilbene compared to resveratrol. Phosphorylation and thus activation of protein kinase C alpha/beta II in activated neutrophils was not decreased by pterostilbene. Pterostilbene in concentrations of 10-100 µM was found to inhibit the activity of human caspase-3 purified enzyme and did not influence cell viability significantly. CONCLUSION: Pterostilbene, an analog of resveratrol, was identified as a good natural antioxidant compound. However, reducing the oxidative burst of human neutrophils during their activation in vitro with pterostilbene does not include protein kinase C phosphorylation pathway. Pterostilbene showed dose dependent activation/inhibition of caspase-3 enzyme activity.

Formation of reactive oxygen and nitrogen species in the presence of pinosylvin - an analogue of resveratrol.

OBJECTIVE: Formation of reactive oxygen species in neutrophils of rats with adjuvant arthritis and generation of nitric oxide in RAW 264.7 macrophages were analysed in the presence of pinosylvin. METHODS AND RESULTS: The method of chemiluminescence was used for the detection of reactive oxygen species in blood of rats with adjuvant arthritis. Pinosylvin (50 mg/kg, daily, p.o.) and methotrexate (0.4 mg/kg, twice a week, p.o.) were applied separately or in a combination over a period of 28 days from the day of immunisation. Adjuvant arthritis was accompanied by a significantly increased number of neutrophils, by elevated concentration of oxidants in blood and by excessive responsiveness of neutrophils to stimulation with PMA. In rats treated with methotrexate, all these changes were significantly reduced and the inhibition became more pronounced when methotrexate was applied in the combination with pinosylvin; the monotherapy with pinosylvin did not induce any detectable changes in the parameters tested. Under in vitro conditions, pinosylvin inhibited formation of nitric oxide (NO) in macrophages, as demonstrated by the decreased concentration of nitrite - the end-product of NO metabolism (assessed by Griess' method), by the reduced expression of inducible NO synthase (detected by Western blot), and by the failure of pinosylvin to scavenge nitric oxide (measured amperometrically in cell-free system). CONCLUSION: The observed ability of pinosylvin to decrease concentration of reactive oxygen and nitrogen species, along with its capacity to enhance the efficacy of methotrexate in arthritis treatment may shed more light into the pharmacological potential of this prospective natural substance.

Different effect of two synthetic coumarin-stilbene hybrid compounds on phagocyte activity.

OBJECTIVE: Activated phagocytes, generating a variety of powerful inflammatory mediators, such as oxygen and nitrogen species, may participate in oxidative stress-mediated inflammation and organ toxicity. At present, great attention is devoted to the important class of phenolic compounds - coumarins - due to their antiinflammatory/antioxidant activities. We compared two synthetic phenylcoumarins: 7-hydroxy-3-(4´-hydroxyphenyl) coumarin (HHC; 0.01-100 µmol/l) and its hydrogenated analogue: 7-hydroxy-3-(4´-hydroxyphenyl)-3,4-dihydrocoumarin (HHDC; 0.01-100 µmol/l) as their ability to inhibit reactive oxygen species (ROS) generation in human neutrophils and nitric oxide (NO) production by RAW 264.7 macrophages in vitro, with respect to some of their physicochemical characteristics. METHODS: ROS production was measured with luminol-enhanced chemiluminescence (CL) in the microplate luminometer Immunotech LM-01T, nitrite formation was determined by the Griess reaction - spectrophotometrically. The radical scavenging assays were employed to assess the antiradical activity values. The relevant physico-chemical parameters of the compounds tested, electronic and hydrophobic, were determined experimentally as well as by suitable computational programmes. RESULTS: Both HHC and HHDC were found to decrease significantly (p<0.01) CL of whole blood stimulated with phorbol myristate acetate (PMA) from the concentration of 1 µmol/l. While HHC significantly inhibited CL stimulated by A23187 and opsonized zymosan (OpZ), HHDC was ineffective. Unlike HHDC, HHC in the concentrations of 10 and 100 µmol/l significantly (p<0.01) reduced NO formation in lipopolysaccharide (LPS) -stimulated murine macrophages RAW 264.7. HHC possessed the higher free radical reducing efficacy in accordance with its more favourable values of electronic parameters in comparison with HHDC. CONCLUSIONS: Our results show the different inhibitory effects of HHC and HHDC on phagocytic activity that might be the result of their diverse free radical scavenging properties and lipophilicity features.

Glucomannan reduces neutrophil free radical production in vitro and in rats with adjuvant arthritis.

The effect of glucomannan (GM), a natural polysaccharide isolated from the yeast Candida utilis, on reactive oxygen species (ROS) generation in human neutrophils in vitro and in rats with Mycobacterium butyricum induced adjuvant arthritis (AA) was tested by the luminol/isoluminol-enhanced chemiluminescence (CL) method. In vitro, GM (500 microg/ml) significantly decreased spontaneous CL of human whole blood, while PMA (4beta-phorbol-12beta-myristate-alpha13acetate)-stimulated CL was decreased by GM in the concentrations of 100 and 500 microg/ml. To specify the site of action of GM, its effect on extra- and intracellular ROS generation in isolated neutrophils was evaluated. GM significantly decreased spontaneous and PMA-stimulated CL and it was more effective extracellularly than intracellularly. In vivo experiments included healthy animals as controls, arthritic animals without any drug administration, and arthritic animals with GM administration (once daily in the oral dose of 15 mg/kg, over a period of 28 days). On day 28, CL in whole blood, spleen and joint was monitored. Arthritic animals treated with GM showed decrease in spontaneous and PMA-stimulated CL of whole blood as well as CL of the joint, in comparison with untreated animals. The obtained findings demonstrated an antioxidant effect of GM in vitro and in rats with AA, which may be due to its free radical scavenger activity and to interaction with different receptors and/or modulation of postreceptor intracellular signalling pathways. The specific physicochemical parameters, such as structure of GM, its low molecular weight and good water solubility, play an important role in the above effects.

Structure-efficiency relationship in derivatives of stilbene. Comparison of resveratrol, pinosylvin and pterostilbene.

OBJECTIVES: Oxidative stress is related to a number of autoimmune diseases, e.g. rheumatoid arthritis, cancer, etc. The main source of pathologically working reactive oxygen species (ROS) are activated polymorphonuclear leukocytes (PMNL). OBJECTIVE: There are some papers comparing structure - pharmacological efficiency relationship of vegetal substances from the stilbenoid group. We compared the effect of trans-resveratrol, which is well-known by its antioxidative activity, with the effect of pinosylvin and pterostilbene. METHODS: Luminol-enhanced chemiluminescence (CL) was used to study the antioxidative action. The effect was observed in whole blood and in isolated PMNL. The concentrations of substances tested were 0.01-100 microM. Due to the different abilities of luminol and isoluminol to pass through the cell membrane, we studied the effect of the substances tested on intracellular and extracellular ROS. To stimulate the production of ROS we used phorbol-myristate-acetate (PMA), which activates PMNL via protein kinase C. RESULTS: Resveratrol, pinosylvin and pterostilbene inhibited significantly the CL of whole blood and extra- and intracellular CL of isolated PMNL in a dosedependent manner. Depending on different functional groups of the stilbene molecule, resveratrol inhibited CL of whole blood and isolated PMNL, whereas pinosylvin influenced mainly intracellular CL and pterostilbene extracellular CL. CONCLUSION: The presence of different functional groups in the molecules of stilbenoids influence their antioxidative effect. Modification of these functional groups may result in derivatives with required antioxidative properties, targeting mainly extracellular ROS which are responsible for tissue damage during chronic inflammation.

The effects of berberine on reactive oxygen species production in human neutrophils and in cell-free assays.

The health benefits of berberine have been recognized for years. Even so, its effects on human neutrophils, the first line of immune defense, have not been reported. The purpose of this study was to investigate the effects of berberine on the human neutrophil oxidative burst. Reactive oxygen species production was analyzed by luminol-enhanced chemiluminescence. The analysis was performed in spontaneous and stimulated (phorbol myristate acetate (PMA) or opsonized zymosan particles (OZP)) whole blood and isolated neutrophils in the presence or absence of berberine. The effects of berberine on oxidant production in cell-free assays were evaluated using luminescence (H2O2-peroxidase-luminol) and fluorescence (Oxygen Radical Absorbance Capacity - ORAC) techniques. Berberine decreased the production of reactive oxygen species in human whole blood and isolated neutrophils stimulated with either PMA or OZP with a different efficiency (EC50 was 69 µM and 197 µM for PMA and OZP, respectively). The effect was more pronounced in isolated neutrophils. Cell-free assays showed the antioxidant activity of berberine against peroxyl radicals and hydrogen peroxide. Based on our results, we suggest that the effects of berberine on reactive oxygen species production in human neutrophils are due to its antioxidant activity.

Pharmacological intervention with oxidative burst in human neutrophils.

In this study we investigated the effect of five therapeutically used drugs and four natural polyphenolic compounds on the mechanism of oxidative burst of human neutrophils concerning their participation in the generation of reactive oxygen species (ROS). The compounds investigated decreased the oxidative burst of whole blood in the rank order of potency: N-feruloylserotonin > quercetin > curcumin > arbutin > dithiaden > carvedilol. The generation of intracellular reactive oxygen species in isolated neutrophils decreased in the same rank order, while carvedilol was ineffective. Scavenging of extracellular oxygen radicals followed the rank order of potency: N-feruloylserotonin > curcumin > quercetin > dithiaden. Arbutin and carvedilol had no effect. All compounds tested increased the activity of caspase-3 in cell-free system indicating a positive effect on apoptosis of neutrophils. Activation of protein kinase C was significantly decreased by dithiaden, curcumin, quercetin and N-feruloylserotonin. Carvedilol, dithiaden, quercetin and arbutin reduced activated neutrophil myeloperoxidase release more significantly compared with their less pronounced effect on superoxide generation The presented results are indicative of pharmacological intervention with neutrophils in pathological processes. Of particular interest was the effect of natural compounds. Intracellular inhibition of oxidative burst in isolated neutrophils by the drugs tested and natural antioxidants has to be further analysed since ROS play an important role in immunological responses of neutrophils.

Nitro-oleic acid regulates growth factor-induced differentiation of bone marrow-derived macrophages.

Many diseases accompanied by chronic inflammation are connected with dysregulated activation of macrophage subpopulations. Recently, we reported that nitro-fatty acids (NO2-FAs), products of metabolic and inflammatory reactions of nitric oxide and nitrite, modulate macrophage and other immune cell functions. Bone marrow cell suspensions were isolated from mice and supplemented with macrophage colony-stimulating factor (M-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) in combination with NO2-OA for different times. RAW 264.7 macrophages were used for short-term (1-5min) experiments. We discovered that NO2-OA reduces cell numbers, cell colony formation, and proliferation of macrophages differentiated with colony-stimulating factors (CSFs), all in the absence of toxicity. In a case of GM-CSF-induced bone marrow-derived macrophages (BMMs), NO2-OA acts via downregulation of signal transducer and activator of transcription 5 and extracellular signal-regulated kinase (ERK) activation. In the case of M-CSF-induced BMMs, NO2-OA decreases activation of M-CSFR and activation of related PI3K and ERK. Additionally, NO2-OA also attenuates activation of BMMs. In aggregate, we demonstrate that NO2-OA regulates the process of macrophage differentiation and that NO2-FAs represent a promising therapeutic tool in the treatment of inflammatory pathologies linked with increased accumulation of macrophages in inflamed tissues.

Lung Neutrophilia in Myeloperoxidase Deficient Mice during the Course of Acute Pulmonary Inflammation.

Systemic inflammation accompanying diseases such as sepsis affects primarily lungs and induces their failure. This remains the most common cause of sepsis induced mortality. While neutrophils play a key role in pulmonary failure, the mechanisms remain incompletely characterized. We report that myeloperoxidase (MPO), abundant enzyme in neutrophil granules, modulates the course of acute pulmonary inflammatory responses induced by intranasal application of lipopolysaccharide. MPO deficient mice had significantly increased numbers of airway infiltrated neutrophils compared to wild-type mice during the whole course of lung inflammation. This was accompanied by higher levels of RANTES in bronchoalveolar lavage fluid from the MPO deficient mice. Other markers of lung injury and inflammation, which contribute to recruitment of neutrophils into the inflamed lungs, including total protein and other selected proinflammatory cytokines did not significantly differ in bronchoalveolar lavage fluid from the wild-type and the MPO deficient mice. Interestingly, MPO deficient neutrophils revealed a decreased rate of cell death characterized by phosphatidylserine surface expression. Collectively, the importance of MPO in regulation of pulmonary inflammation, independent of its putative microbicidal functions, can be potentially linked to MPO ability to modulate the life span of neutrophils and to affect accumulation of chemotactic factors at the inflammatory site.