Pharmacological regulation of neutrophil activity and apoptosis: Contribution to new strategy for modulation of inflammatory processes

Novel strategies of antiinflammatory therapy are based upon pharmacological agents capable to enhance the resolution – i.e. the termination of the beneficial inflammation before it may turn into an adverse chronic stage. In contrast to the current therapy, which antagonises the formation of proinflammatory mediators, the “proresolving” therapy promotes natural antiinflammatory processes. It is likely that several drugs and phytochemicals would act in this way, but this point has not been investigated and thus might be totally overlooked. In this paper, effects of curcumin (diferuloylmethane) were analysed, considering the ability of this natural compound to affect resolution of inflammation through modulation of its important inputs – activity and apoptosis of neutrophils. The presented data indicate that, besides its well-known ability to suppress mechanisms engaged at the onset and progression of inflammation, curcumin could support resolution of inflammation through decreased activity and enhanced apoptosis of neutrophils. This substance decreased the formation of oxidants in neutrophils, both under in vitro conditions and after oral administration to arthritic rats. Moreover, curcumin accelerated spontaneous apoptosis of neutrophils, as indicated by increased externalisation of phosphatidylserine, by intercalation of propidium iodide and by enhanced activity of the executioner caspase-3

Immunobiological properties of selected natural and chemically modified phenylpropanoids

Effects of natural and structurally transformed lignans compared with stilbenes or stilbenoids on production of nitric oxide (NO) triggered by lipopolysaccharide (LPS) and interferon-γ (IFN-γ), tested under in vitro conditions using murine resident peritoneal macrophages, are reviewed. Relation between the molecular structure and immunobiological activity was investigated, and implication of substituents, double bond stereochemistry, or cyclic attachments (double bond geometry fixation) was assessed. The focus was on lignans and stilbenoids because they were originally selected for a joint project of common interest to phytochemical and pharmacological investigation and because they represent well interesting and universally attractive groups of polyphenols with a feasible potential for therapeutic or nutraceutic utilization

Modulation of metabolic activity of phagocytes by antihistamines

The purpose of the study was to investigate the effects of H1-antihistamines of the 1st generation (antazoline, bromadryl, brompheniramine, dithiaden, cyclizine, chlorcyclizine, chlorpheniramine, clemastine) and the 2nd generation (acrivastine, ketotifen, and loratadine) on the respiratory burst of phagocytes. Reactive oxygen species generation in neutrophils isolated from rat blood was measured using luminol-enhanced chemiluminescence. Changes in nitrite formation and iNOS protein expression by RAW 264.7 macrophages were analysed using Griess reaction and Western blotting. The antioxidative properties of drugs in cell-free systems were detected spectrophotometrically, luminometrically, fluorimetrically, and amperometrically. The majority of the H1-antihistamines tested (bromadryl, brompheniramine, chlorcyclizine, chlorpheniramine, clemastine, dithiaden, and ketotifen) exhibited a significant inhibitory effect on the chemiluminescence activity of phagocytes. H1-antihistamines did not show significant scavenging properties against superoxide anion and hydroxyl radical, thus this could not contribute to the inhibition of chemiluminescence. H1-antihistamines had a different ability to modulate nitric oxide production by LPS-stimulated macrophages. Bromadryl, clemastine, and dithiaden were the most effective since they inhibited iNOS expression, which was followed by a significant reduction in nitrite levels. H1-antihistamines had no scavenging activity against nitric oxide. It can be concluded that the effects observed in the H1-antihistamines tested are not mediated exclusively via H1-receptor pathway or by direct antioxidative properties. Based on our results, antihistamines not interfering with the microbicidal mechanisms of leukocytes (antazoline, acrivastine and cyclizine) could be used preferentially in infections. Other antihistamines should be used, under pathological conditions accompanied by the overproduction of reactive oxygen species

The ATPase and protease domains of yeast mitochondrial Lon: Roles in proteolysis and respiration-dependent growth

The ATP-dependent Lon protease of Saccharomyces cerevisiae mitochondria is required for selective proteolysis in the matrix, maintenance of mitochondrial DNA, and respiration-dependent growth. Lon may also possess a chaperone-like function that facilitates protein degradation and protein-complex assembly. To understand the influence of Lon’s ATPase and protease activities on these functions, we examined several Lon mutants for their ability to complement defects of Lon-deleted yeast cells. We also developed a rapid procedure for purifying yeast Lon to homogeneity to study the enzyme’s activities and oligomeric state. A point mutation in either the ATPase or the protease site strongly inhibited the corresponding activity of the pure protein but did not alter the protein’s oligomerization; when expressed at normal low levels neither of these mutant enzymes supported respiration-dependent growth of Lon-deleted cells. When the ATPase- or the protease-containing regions of Lon were expressed as separate truncated proteins, neither could support respiration-dependent growth of Lon-deleted cells; however, coexpression of these two separated regions sustained wild-type growth. These results suggest that yeast Lon contains two catalytic domains that can interact with one another even as separate proteins, and that both are essential for the different functions of Lon

Colloidal polyaniline dispersions: Antibacterial activity, cytotoxicity and neutrophil oxidative burst

Polyaniline colloids rank among promising application forms of this conducting polymer. Cytotoxicity, antibacterial activity, and neutrophil oxidative burst tests were performed on cells treated with colloidal polyaniline dispersions. The antibacterial effect of colloidal polyaniline against gram-positive and gram-negative bacteria was most pronounced for Bacillus cereus and Escherichia coli, with a minimum inhibitory concentration of 3500μgmL-1. The data recorded on human keratinocyte (HaCaT) and a mouse embryonic fibroblast (NIH/3T3) cell lines using an MTT assay and flow cytometry indicated a concentration-dependent cytotoxicity of colloid, with the absence of cytotoxic effect at around 150μgmL-1. The neutrophil oxidative burst test then showed that colloidal polyaniline, in concentrations <150μgmL-1, was not able to stimulate the production of reactive oxygen species in neutrophils and whole human blood. However, it worked efficiently as a scavenger of those already formed. © 2014 Elsevier B.V.13-08944S, GACR, Czech Science FoundationCzech Science Foundation [13-08944S]; OPVK [CZ.1.07/2.3.00/30.0030