The expression of NADPH oxidases and production of reactive oxygen species by human lung adenocarcinoma epithelial cell line A549

Controlled production of reactive oxygen species (ROS) by NADPH oxidases in non-phagocytic cells has recently been suggested to participate in the regulation of cellular functions. Due to the role of ROS in control of cellular functions, precise and accurate detection of ROS is of essential importance. However, various methodological approaches currently used for ROS determination vary in sensitivity, specificity, as well as in requirements for specialized equipment. In this study, human lung epithelial cell line A549 was screened for expression of NADPH oxidases NOX1, NOX2, NOX4, NOX5, DUOX1 and DUOX2 by quantitative RT-PCR. Fluorometric, colorimetric, and chemiluminometric methods were applied to determine ROS production. A549 cells were found to significantly express NOX1, NOX2, DUOX1 and DUOX2. ROS production by A549 cells was detected with fluorometric probes 2',7'-dichlorofluorescein- diacetate, dihydroethidium, and amplex red or colorimetric probe nitrobluetetrazolium. The production of ROS detected by these probes was partially reduced by NADPH oxidase inhibitor diphenyleneiodonium. The inhibitory effect of diphenyleneiodonium was the most significant regarding amplex red detection of phorbol myristate acetateactivated ROS production. In contrast to other probes, neither cytochrome c colorimetric determination nor luminol- and L-012-amplified chemiluminescence, regardless of the addition of horseradish peroxidase, exerted sufficient sensitivity to detect ROS production by A549. The results revealed differences among methods used for ROS formation measurement by human lung epithelial cell line A549 and highlighted the sensitivity of fluorometric determination for this purpose.

Dynamic Monitoring of Cellular Remodeling Induced by the Transforming Growth Factor-β1

The plasticity of differentiated adult cells could have a great therapeutic potential, but at the same time, it is characteristic of progression of serious pathological states such as cancer and fibrosis. In this study, we report on the application of a real-time noninvasive system for dynamic monitoring of cellular plasticity. Analysis of the cell impedance profile recorded as cell index using a real-time cell analyzer revealed its significant increase after the treatment of prostate epithelial cells with the transforming growth factor-β1. Changes in the cell index profile were paralleled with cytoskeleton rebuilding and induction of epithelial–mesenchymal transition and negatively correlated with cell proliferation. This novel application of such approach demonstrated a great potential of the impedance-based system for noninvasive and real-time monitoring of cellular fate.

Carvedilol and adrenergic agonists suppress the lipopolysaccharide-induced NO production in RAW 264.7 macrophages via the adrenergic receptors

The interaction of adrenergic agonists and/or antagonists with the adrenergic receptors expressed on immunologically active cells including macrophages plays an important role in regulation of inflammatory responses. Our study investigated the effects of carvedilol, a unique vasodilating beta-adrenergic antagonist, and endogenous adrenergic agonists (adrenalin, noradrenalin, and dopamine) and/or antagonists (prazosin, atenolol) on lipopolysaccharide-stimulated nitric oxide (NO) production from murine macrophage cell line RAW 264.7. The production of NO was determined as the concentration of nitrites in cell supernatants (Griess reaction) and inducible nitric oxide synthase (iNOS) protein expression (Western blot analysis). Scavenging properties against NO were measured electrochemically. Carvedilol in a concentration range of 1, 5, 10 and 25 microM inhibited iNOS protein expression and decreased the nitrite concentration in cell supernatants. Adrenalin, noradrenalin or dopamine also inhibited the iNOS protein expression and the nitrite accumulation. Prazosine and atenolol prevented the effect of both carvedilol and adrenergic agonists on nitrite accumulation and iNOS expression in lipopolysaccharide-stimulated cells. These results, together with the absence of scavenging properties of carvedilol against NO, imply that both carvedilol and adrenergic agonists suppress the lipopolysaccharide-evoked NO production by macrophages through the activation and modulation of signaling pathways connected with adrenergic receptors.

The influence of wine polyphenols on reactive oxygen and nitrogen species production by murine macrophages RAW 264.7

The aim was to study the antioxidant properties of four wine polyphenols (flavonoids catechin, epicatechin, and quercetin, and hydroxystilbene resveratrol). All three flavonoids exerted significant and dose-dependent scavenging effects against peroxyl radical and nitric oxide in chemical systems. The scavenging effect of resveratrol was significantly lower. All polyphenols decreased production of reactive oxygen species (ROS) by RAW264.7 macrophages. Only quercetin quenched ROS produced by lipopolysaccharide-stimulated RAW264.7 macrophages incubated for 24 h with polyphenols. Quercetin and resveratrol decreased the release of nitric oxide by these cells in a dose-dependent manner which corresponded to a decrease in iNOS expression in the case of quercetin. In conclusion, the higher number of hydroxyl substituents is an important structural feature of flavonoids in respect to their scavenging activity against ROS and nitric oxide, while C-2,3 double bond (present in quercetin and resveratrol) might be important for inhibition of ROS and nitric oxide production by RAW 264.7 macrophages.

Phagocyte-derived oxidants and plasma antioxidants in haemodialysed patients

OBJECTIVE

Oxidative stress is one of the important complications occurring in haemodialysis. The aim of the study was to determine haemodialysis-induced changes in oxidative burst of phagocytes and the antioxidative properties of plasma.

METHODS

Twenty-seven patients and 50 healthy controls were examined. Oxidative burst of phagocytes and plasma antioxidative potential were measured luminometrically. Concentrations of major plasma antioxidants (vitamin E, bilirubin and uric acid) were also determined.

RESULTS

Phagocyte chemiluminescence was higher in patients before haemodialysis compared with that in controls and decreased after haemodialysis compared with predialysis status. A significant increase in plasma antioxidative potential and uric acid was found in patients before haemodialysis. These parameters decreased after haemodialysis compared with both predialysis and control values.

CONCLUSIONS

The higher generation of phagocyte-derived oxidants and the decline in plasma antioxidative properties after haemodialysis confirm insufficient antioxidant defence in patients with chronic renal failure.

Neural differentiation potentiated by the leukaemia inhibitory factor through STAT3 signalling in mouse embryonal carcinoma cells

LIF is a cytokine playing a key role in the regulation of self-renewal and maintenance of undifferentiated state in mouse ES cells. The response of pluripotent cells to LIF is mediated mainly by the STAT3 and ERK signalling pathways. Recently, we have shown that LIF potentiated retinoic acid-induced neural differentiation of pluripotent mouse embryonal carcinoma P19 cells. Here we demonstrate that pro-neural effects of LIF and partially also of retinoic acid are abolished by inhibition of the JAK2->STAT3 signalling pathway. In contrast, inhibition of the MEK1->ERK signalling pathway does not exhibit any effect. These results suggest that in neurogenic regions, cooperative action of LIF and other neuro-differentiation-inducing factors, such as retinoic acid, may be mediated by the STAT3 signalling pathway.

Blood phagocyte activation during open heart surgery with cardiopulmonary bypass

Open heart surgery with a cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response which significantly contributes to adverse postoperative complications. The purpose of this study was to characterize the activation of blood phagocytes during open heart surgery with CPB. Blood samples were collected during and up to 24 h after surgery. The production of reactive oxygen species (ROS) in whole blood, the expression of surface molecules by blood phagocytes and complement activity in the plasma were determined. A cDNA microarray analysis of leukocyte RNA profile of genes was performed related to the inflammatory response. Activation of the complement was already observed at the beginning of CPB. This was followed by an increase in the neutrophil number and in both spontaneous and opsonized zymosan-activated ROS production after the onset of reperfusion. The activation of blood phagocytes was affirmed by changes in surface receptors involved in the adhesion and migration of leukocytes (CD11b, CD62L and CD31). Gene arrays also confirmed the activation of leukocytes 4 h after reperfusion. In conclusion, open heart surgery with a cardiopulmonary bypass was found to be associated with a rapid and pronounced activation of blood phagocytes and complement activation which was partly independent at the onset of CPB.

Neural differentiation of pluripotent mouse embryonal carcinoma cells by retinoic acid: inhibitory effect of serum

In both embryonal carcinoma (EC) and embryonic stem (ES) cells, the differentiation pathway entered after treatment with retinoic acid (RA) varies as it is based upon different conditions of culture. This study employs mouse EC cells P19 to investigate the effects of serum on RA-induced neural differentiation occurring in a simplified monolayer culture. Cell morphology and expression of lineage-specific molecular markers document that, while non-neural cell types arise after treatment with RA under serum-containing conditions, in chemically defined serum-free media RA induces massive neural differentiation in concentrations of 10(-9) M and higher. Moreover, not only neural (Mash-1) and neuroectodermal (Pax-6), but also endodermal (GATA-4, alpha-fetoprotein) genes are expressed at early stages of differentiation driven by RA under serum-free conditions. Furthermore, as determined by the luciferase reporter assay, the presence or absence of the serum does not affect the activity of the retinoic acid response element (RARE). Thus, mouse EC cells are able to produce neural cells upon exposure to RA even without culture in three-dimensional embryoid bodies (EBs). However, in contrast to standard EBs-involving protocol(s), neural differentiation in monolayer only takes place when complex signaling from serum factors is avoided. This simple and efficient strategy is proposed to serve as a basis for neurodifferentiation studies in vitro.

Silkworm (Bombyx mori) hemocytes do not produce reactive oxygen metabolites as a part of defense mechanisms

To investigate whether hemocytes of Bombyx mori (Lepidoptera) larvae produce reactive oxygen species (ROS) as part of the oxidative killing of invading pathogens, the production of ROS was measured as a luminol- and lucigenin-enhanced chemiluminescence of unstimulated or stimulated (zymosan particles, phorbol myristate acetate, calcium ionophore, rice starch or Xenorhabdus nematophila) hemolymph. No detectable ROS production was found. The spontaneous and activated ROS production measured with hemocytes, i.e. under the conditions when the antioxidative potential of hemolymph plasma was eliminated, was again undetectable. Likewise, ROS production by isolated hemocytes was observed by spectrophotometric (NBT test, cytochrome c assay) and fluorimetric (using dihydrorhodamine and hydroethidine probes) methods. Hence none of the experimental approaches used indicated the production of ROS by hemocytes of B. mori larvae as part of their immune response.

The effect of intestinal ischemia duration on changes in plasma antioxidant defense status in the rats

The purpose of this study was to follow up the changes in antioxidative adaptive mechanisms induced by various periods of small intestinal ischemia in Wistar rats. The superior mesenteric artery was occluded for 15, 30, 45, 60 and 90 min. After the respective ischemic intervals, a reperfusion was set for 120 min. Samples of the serum and intestinal mucosa were taken at the end of ischemia or at the end of reperfusion. Total radical-trapping antioxidant parameter (TRAP) of the serum and the oxidative burst of neutrophils were evaluated using luminol-enhanced chemiluminescence. Individual antioxidants in the serum and the concentration of thiobarbituric acid reactive substances (TBARs) in both serum and intestinal mucosa were measured spectrophotometrically. Increased activation of circulating neutrophils was found after the reperfusion irrespective of the duration of ischemia. TRAP of the serum was increased at the end of the ischemia lasting from 30 to 90 min. This effect was further enhanced by the subsequent reperfusion period. Ascorbate and urate contributed considerably to the TRAP value especially after reperfusion following 60 and 90 min of ischemia. On the other hand, no significant changes in albumin and bilirubin serum concentrations were observed. Contrary to the mobilized antioxidative mechanisms, increased lipid peroxidation was observed in both serum and mucosa samples.

The effect of intestinal ischemia duration on changes in plasma antioxidant defense status in rats

The purpose of this study was to follow up the changes in antioxidative adaptive mechanisms induced by various periods of small intestinal ischemia in Wistar rats. The superior mesenteric artery was occluded for 15, 30, 45, 60 and 90 min. After the respective ischemic intervals, a reperfusion was set for 120 min. Samples of the serum and intestinal mucosa were taken at the end of ischemia or at the end of reperfusion. Total radical-trapping antioxidant parameter (TRAP) of the serum and the oxidative burst of neutrophils were evaluated using luminol-enhanced chemiluminescence. Individual antioxidants in the serum and the concentration of thiobarbituric acid reactive substances (TBARs) in both serum and intestinal mucosa were measured spectrophotometrically. Increased activation of circulating neutrophils was found after the reperfusion irrespective of the duration of ischemia. TRAP of the serum was increased at the end of the ischemia lasting from 30 to 90 min. This effect was further enhanced by the subsequent reperfusion period. Ascorbate and urate contributed considerably to the TRAP value especially after reperfusion following 60 and 90 min of ischemia. On the other hand, no significant changes in albumin and bilirubin serum concentrations were observed. Contrary to the mobilized antioxidative mechanisms, increased lipid peroxidation was observed in both serum and mucosa samples.

IL-10 does not affect oxidative burst and expression of selected surface antigen on human blood phagocytes in vitro

Cytokines play a major role in the control of inflammatory responses, participate in the regulation of blood phagocyte activities and as such are used for immunomodulatory therapy. In the present study, the influence of IL-10 on human blood phagocyte activity in the presence/absence of IL-6, IL-8 and TNF-a was tested in vitro. Our research analyzed the effects of cytokines on the production of reactive oxygen species measured by chemiluminescence and flow cytometry, and on the expression of surface molecules (CD11b, CD15, CD62L, CD31) measured by flow cytometry. IL-10 had no inhibitory effect on reactive oxygen species production and the expression of any examined adhesion molecule by resting or stimulated blood phagocytes within 3 h of incubation. Conversely, TNF-, IL-6, and IL-8 increased reactive oxygen species production and the expression of CD11b and CD15 on both neutrophils and monocytes and decreased the expression of CD62L. These priming effects of the tested pro-inflammatory cytokines were not affected by IL-10. The obtained results suggest that IL-10 does not directly control blood phagocyte activation. These results also provide better information about the contribution of IL-6, IL-8 and TNF- to the regulation of blood phagocyte-mediated inflammatory processes.

IL-10 does not affect oxidative burst and expression of selected surface antigen on human blood phagocytes in vitro

Cytokines play a major role in the control of inflammatory responses, participate in the regulation of blood phagocyte activities and as such are used for immunomodulatory therapy. In the present study, the influence of IL-10 on human blood phagocyte activity in the presence/absence of IL-6, IL-8 and TNF-alpha was tested in vitro. Our research analyzed the effects of cytokines on the production of reactive oxygen species measured by chemiluminescence and flow cytometry, and on the expression of surface molecules (CD11b, CD15, CD62L, CD31) measured by flow cytometry. IL-10 had no inhibitory effect on reactive oxygen species production and the expression of any examined adhesion molecule by resting or stimulated blood phagocytes within 3 h of incubation. Conversely, TNF-alpha, IL-6, and IL-8 increased reactive oxygen species production and the expression of CD11b and CD15 on both neutrophils and monocytes and decreased the expression of CD62L. These priming effects of the tested pro-inflammatory cytokines were not affected by IL-10. The obtained results suggest that IL-10 does not directly control blood phagocyte activation. These results also provide better information about the contribution of IL-6, IL-8 and TNF-alpha to the regulation of blood phagocyte-mediated inflammatory processes.

[Antioxidative action of pyridoindoles and N-(alkoxyphenyl)-2-(2-oxo-1-aza-1-cycloalkyl) acetamides in biological, enzymatic and chemical systems]

The luminol-enhanced chemiluminiscence method was used to investigate the antioxidative activity of N-(alkoxyphenyl)-2-(2-oxo-1-aza-1-cykloalkyl) acetamides studied as potential cognitive enhancers and stobadine acylderivatives which form prodrugs with increased lipophilicity. The effect on the production of reactive oxygen metabolites by activated leukocytes was studied in vitro. Furthermore, the total radical-trapping antioxidant parameter was evaluated as the peroxyl radical-trapping capacity and the scavenging effect on the superoxide anion radical (generated by the enzymatic system hypoxanthine/xanthine oxidase) and on the hydroxyl radical (produced in Fenton reaction) were studied. The antioxidative properties of the tested substances were compared with that of stobadine dihydrochloride. Only stobadine and its butyrylderivative have been demonstrated to possess free radical scavenging activity in all systems. Cinnamoylstobadine inhibited only the leukocyte chemiluminiscence activity. The potential cognitive enhancers did not show any antioxidant activity.

Influence of polysulfone and hemophan hemodialysis membranes on phagocytes

The aim of the study was to compare the effect of hemophane and polysulfone membranes on the phagocyte-derived production of reactive oxygen species (ROS) as well as on neutrophil CD11b and CD62L expression in patients undergoing regular hemodialysis. The effects of hemodialysis membranes were also studied in in vitro conditions after coincubating them with differentiated HL-60 cells. ROS production was measured using chemiluminometric and flow cytometric methods. Expression of CD11b, CD62L and mitochondrial membrane potential were detected by monoclonal antibodies and by the JC-1 fluorescent probe, respectively. Depressed ROS production was observed in patients already before dialysis. Further decrease in ROS production and an increase in CD11b expression were observed especially in patients after hemophan hemodialysis. Decreased ROS production and increased CD11b expression were observed also after incubation of HL-60 cells with hemophan membranes. Mitochondrial membrane potential dropped only after incubating cells with hemophan membranes proving its more serious adverse effects in comparison with the polysulfone membrane. In conclusion, deleterious effects of hemodialysis on the metabolic activity of phagocytes were proved. Combining chemiluminescent and flow cytometric methods for the detection of ROS production and determining mitochondrial membrane potential can be useful tools for the analysis of material biocompatibility.

Differential effects of v-Jun and c-Jun proteins on v-myb-transformed monoblasts

The v-myb oncogene of avian myeloblastosis virus transforms myelomonocytic cells in vitro. The line of v-myb-transformed chicken monoblasts BM2 can be induced to terminal differentiation using phorbol esters. The fact that Jun proteins are up-regulated in the phorbol ester-treated BM2 cells prompted us to investigate the role of the Jun proteins in regulation of myeloid differentiation. We ectopically expressed v-jun and c-jun in BM2 cells and evaluated their effects on differentiation and proliferation. c-Jun up-regulated the transactivation activity of v-Myb and induced a proliferation block and differentiation of BM2 cells. In contrast, v-Jun down-regulated v-Myb transactivation causing no dramatic effects on BM2 cells. This confirms that there is no strong correlation between transcriptional activation and strength of oncogenic transformation by v-Myb. Both c-Jun and v-Jun proteins affected sensitivity of BM2 cells to retinoic acid and phorbol ester. Sensitivity of BM2 cells to retinoic acid was enhanced by both Jun proteins, while sensitivity to phorbol 12-myristate 13-acetate was reduced by v-Jun. These data suggest thate Jun plays a major role in macrophage differentiation.

Peri- and post-operative course of cytokines and the metabolic activity of neutrophils in human liver transplantation

Peri- and post-operative (up to day 7 after surgery) neutrophil chemiluminescence and the plasma concentrations of interleukin 6 (IL-6), IL-8, IL-10 and tumour necrosis factor alpha (TNF-alpha) were evaluated in the blood of patients undergoing liver transplantation. IL-6, IL-8 and IL-10 levels increased during early reperfusion and then returned to normal mostly within the first post-operative day. TNF-alpha was increased during the whole period observed. Spontaneous as well as activated neutrophil chemiluminescence was depressed in early reperfusion and remained low during the whole period followed. Samples collected during early reperfusion provided positive correlation for IL-6 vs IL-8 as well as for IL-6 and IL-8 vs chemiluminescence. The data were also evaluated with respect to the outcome of transplantation. Since IL-8, IL-10 and TNF-alpha levels increased significantly during the first post-operative week, mainly in a group of patients who developed serious complications within the first month after surgery, we proved a connection between peri- and early post-operative induction of cytokine release and the outcome of liver allograft transplantation.

Total antioxidant capacity of serum increased in early but not late period after intestinal ischemia in rats

The ischemia of small intestine was induced in anesthetized Wistar rats by occluding the superior mesenteric artery for 45 min and then the reperfusion was set. Serum samples were obtained at the end of the ischemic period and also during early (1 to 4 h) and late postischemic period (1 to 4 d). The total antioxidant capacity (TRAP) of serum samples was evaluated using luminol enhanced chemiluminescence. The increased mobilization of phagocytic cells and the release of reactive oxygen species into the circulation was observed from the first and second hour of the postischemic period, respectively. Nevertheless, the activity of natural antioxidant mechanisms of serum was already elicited at the end of the ischemic period. Furthermore, the TRAP of serum increased with the increasing duration of early postischemic period. Among the antioxidants studied, urate and ascorbate concentrations exerted the highest correlation with TRAP, but 31.6% of the total antioxidant capacity remained for the activity of an unidentified antioxidant(s). After being exhausted, the TRAP of serum oscillated around the preoperation level at days 1-4 of the postischemic period. The increase in total antioxidant capacity of serum induced by oxidative stress was sufficient to prevent lipoperoxidation both in serum and intestinal tissue.

Phagocyte-induced oxidative stress in patients with haemodialysis treatment and organ transplantation

The aim of the study was to examine the phagocyte-derived production of reactive oxygen species (ROS), lipoperoxidation and the total radical-trapping antioxidant parameter (TRAP) in patients undergoing regular haemodialysis (HD) followed by kidney transplantation (n = 13). A significant increase in both spontaneous and activated ROS generation was found during the post-transplantation period in days 1-3. This effect was caused mainly by an increased number of neutrophils. On the other hand, the TRAP parameter was decreased in HD patients. After kidney transplantation, the TRAP parameter increased, reaching the level of healthy controls at the end of the first week after surgery. Increase in MDA level was determined after HD and kidney transplantation. It can be concluded from the results obtained that phagocyte mobilisation and increased oxidative stress after HD and kidney transplantation were associated with the insufficient activity of extracellular antioxidant mechanisms resulting in increased lipid peroxidation.

Leukocyte mobilization, chemiluminescence response, and antioxidative capacity of the blood in intestinal ischemia and reperfusion

Intestinal ischemia and reperfusion elicits changes in leukocyte counts and increased production of reactive oxygen species (ROS). The purpose of this study was to investigate whether these changes were followed by and/or connected with changes in the extracellular antioxidative capacity in a rat superior mesenteric artery (SMA) occlusion/reperfusion model. The SMA was occluded for 45 min and then allowed to be reperfused. Changes of leukocyte, polymorphonuclear (PMN), and lymphocyte counts, chemiluminescence (CL) of whole blood samples as a marker of ROS production, and the total antioxidative capacity of the serum were quantified at the end of ischemia and in 1 h intervals during the postischemic period up to 4 h. The myeloperoxidase (MPO) activity in the serum and intestinal tissue samples was also determined. The MPO activity in the intestinal tissue samples was significantly elevated at the end of ischemia, and this elevation lasted for the whole postischemic period. The oxidative challenge to the body induced a fast mobilization of extracellular antioxidative mechanisms already at the end of ischemia, which was followed by a significant increase in PMN counts and whole blood CL starting at the 2nd hour after reperfusion. The increased CL activity of whole blood was attributed to the increase of the circulating PMNs. No significant changes were observed in leukocyte and lymphocyte counts. It is concluded that compensatory mechanisms of the oxidative-antioxidative balance of the body react very quickly if challenged.

[Results of two year use of dipyridamole and metindol in patients with primary focal and (or) segmental glomerulosclerosis]

Primary focal or segmental glomerulosclerosis is neuropathy diagnosed in 10% of children and 20% of adult patients with nephrotic syndrome. Immunosuppressive therapy was applied during two years period. The very good clinical results were obtained in 20% and good results in 40% of patients after indomethacin and dipyridamole therapy.