Regulation of murine dendritic cell functions in vitro by taurine chloramine, a major product of the neutrophil myeloperoxidase-halide system

Taurine chloramine (TauCl) is a major chloramine generated in activated neutrophils as a result of the reaction of highly toxic hypochlorous acid and taurine, the most abundant free amino acid in cytosol. In this study we have tested the influence of TauCl on the properties of murine dendritic cells (DC), the major cell population involved in the initiation of an adaptive immune response against pathogenic organisms. N418+, MHC II+, B7-2+ dendritic cells, generated from the mouse bone marrow cells cultured in the presence of granulocyte-macrophage colony-stimulating factor, were stimulated by interferon-gamma and lipopolysaccharide to produce nitric oxide, reactive oxygen species, interleukin-6 (IL-6), tumour necrosis factor-alpha, and IL-12, in the presence of different doses of TauCl. TauCl differently inhibited the generation of these inflammatory mediators in a dose-dependent manner. Furthermore, TauCl selectively modulated the ability of DC to induce the release IL-2 and IL-10 from T cells. These results suggest that neutrophil-derived mediators, such as TauCl, at a site of inflammation, may affect the functions of sentinel DC and macrophages, and play a role in maintaining the balance between the inflammatory response and the induction of an antigen-specific immune response.     

Is there a role of taurine bromamine in inflammation? Interactive effects with nitrite and hydrogen peroxide

Objective and Design: The myeloperoxidase system of neutrophils generates chlorinating and brominating oxidants in vivo. The major haloamines of the system are taurine chloramine (TauCl) and taurine bromamine (TauBr). It has been demonstrated in vitro that TauCl exerts both antiinflammatory and anti-bacterial properties. Much less is known about TauBr. The present study was conducted to compare bactericidal and immunoregulatory capacity of TauBr with that of the major chlorinating oxidants: HOCl and TauCl. Moreover, the effect of nitrites and H₂O₂ on TauBr activity was investigated.Materials: TauBr was prepared by reaction of HOBr with taurine. The reaction was monitored by UV absorption spectra.Methods: Bactericidal activity of TauBr, TauCl and HOCl was tested by incubation of E. coli with the compounds and determined by the pour-plate method. To test the anti-inflammatory activity the compounds were incubated with LPS and IFN- stimulated murine peritoneal macrophages. The production of following mediators was measured: nitrites by Griess reaction; TNF-, IL-6, IL-10, IL-12p40 using capture ELISA. In some experiments the compounds were incubated with either nitrites or H₂O₂.Results: In our experimental set-up TauBr and HOCl exerted strong bactericidal effects on E. coli (MBC = 110 M and 8 M, respectively), while TauCl (< 1000 M) did not kill test bacteria. However, both, TauBr and TauCl, at noncytotoxic concentrations (< 300 M) inhibited the cytokine and nitric oxide production by macrophages. H₂O₂ completely abolished the biological activities of TauBr but not those of TauCl. Nitrites did not affect any activity of TauBr or TauCl while they diminished the HOCl^– mediated bacterial killing.Conclusion: TauBr, despite very low concentration of Br^– in body fluids, may support TauCl and HOCl in the regulation of inflammatory response and in killing of bacteria by neutrophils. However, TauBr activity in vivo will depend on the presence of H₂O₂ and possible other mediators of inflammation which can compete with target molecules for TauBr.Received 16 August 2004; returned for revision 16 September 2004; accepted by A. Falus 13 October 2004     

Nerve growth factor (NGF) promotes angiogenesis in the quail chorioallantoic membrane.

Angiogenesis, the formation of new blood vessels, is tightly regulated by growth factors, such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). The authors hypothesize that nerve growth factor (NGF), a well known neurotrophin, may play a direct angiogenic role. To test this hypothesis, the authors measured the effects of NGF on the natural vascularization of the quail chorioallantoic membrane (CAM). The angiogenic effect of NGF was compared to that of human recombinant VEGF165 (rhVEGF) and basic FGF (rhbFGF). In comparison to phosphate-buffered saline-treated controls, NGFs from different biological sources (mouse, viper, and cobra) increased the rate of angiogenesis in a dose-dependent fashion from 0.5 to 5 microg. For quantitative morphometry, grayscale images of the blood vessels end points of the CAM arteries were binarized for visualization and skeletonized for quantization by fractal analysis. In mouse NGF-treated embryos the fractal dimension (Df), indicative of arterial vessel length and density, increased to 1.266 +/- 0.021 compared to 1.131 +/- 0.018 (p < .001) for control embryos. This effect was similar to that of 0.5 microg rhVEGF (1.290 +/- 0.021, p < .001) and 1.5 microg rhbFGF (1.264 +/- 0.028, p < .001). The mouse NGF-induced angiogenic effect was blocked by 1 microM K252a (1.149 +/- 0.018, p < .001), an antagonist of the NGF/trkA receptor, but not by 1 microM SU-5416 (1.263 +/- 0.029, p < .001), the VEGF/Flk1 receptor antagonist, indicating a direct, selective angiogenic effect of NGF via quail embryo trkA receptor activation. These results confirm previous observations that NGF has angiogenic activity and suggest that this neurotrophin may also play an important role in the cardiovascular system, besides its well-known effects in the nervous system. The angiogenic properties of NGF may be beneficial in engineering new blood vessels and for developing novel antiangiogenesis therapies for cancer.     

Oxidative modification of type II collagen differentially affects its arthritogenic and tolerogenic capacity in experimental arthritis

INTRODUCTION: Oxidative modification of proteins affects their biological properties. Previously we have shown that hypochlorite (HOCl), the product of activated neutrophils, enhances protein immunogenecity. Collagen type II, a primary component of cartilage, is commonly used in the induction of arthritis in animals (CIA). The aim of this study was to examine whether HOCl may affect immunogenic, tolerogenic, and arthritogenic properties of collagen. MATERIALS AND METHODS: DBA/J mice were injected with either native (CNAT) or chlorinated collagen (CHOCl) to induce arthritis. The effect of chlorination on collagen properties was measured by evaluation of incidence and severity of CIA. Moreover, the concentration of serum anti-collagen IgG antibodies and myeloperoxidase (MPO) activity in inflamed joints was determined. RESULTS: Mice immunized with CNAT in adjuvant developed arthritis (CIA) with an incidence of 69%. CNAT also exerted tolerogenic properties when injected intravenously either before or shortly after primary immunization, resulting in decreased incidence and severity of CIA, reduced MPO activity in inflamed joints, and lowered serum levels of anti-CNAT IgG anti-bodies. Chlorination of collagen significantly diminished its ability to induce CIA and to trigger generation of anti-CNAT IgG antibodies. Interestingly, chlorination did not affect tolerogenic properties of collagen administered prior to primary immunization with CNAT. CONCLUSIONS: These results suggest that chlorination of collagen may selectively affect functional epitopes of collagen. It is likely that in inflamed joints, neutrophil derived HOCl, in some circumstances, will destroy arthritogenic and immunogenic B cell epitopes, while regulatory T cell epitopes will be preserved.     

Gender differences and bleeding complications after PCI on first and second generation DES

Background. The aim of this study was to evaluate gender differences in the long-term clinical outcomes and safety of patients treated with first- and second generation DES. Methods. The Katowice–Zabrze Registry included 1916 consecutive patients treated with either first or second generation DES. We evaluated major adverse cardiac and cerebrovascular events (MACCE) [composite of death, myocardial infarction (MI), stroke and target vessel revascularization (TVR)] at 12-month follow-up. Safety end point was bleeding complications and stent thrombosis. Results. Registry included [unstable angina (UA) 1500(78%), non-ST-segment elevation myocardial infarction (NSTEMI) 285 (15%), ST-segment elevation myocardial infarction/left bundle branch block (STEMI/LBBB) 131 (7%)]. There were 35.5% females and 64.5% males. Women were older and had higher prevalence of comorbidities. Males more often had multivessel disease and higher Syntax score when comparable to females. We did not observed difference in acute and subacute stent thrombosis in our data, however, females had more in-hospital bleeding complications. Univariable Cox regression analysis revealed that women had similar outcomes when compared to men in terms of a risk of death, MI, TVR, stroke and MACCE at 1-year follow-up. There were no differences between males and females in MACCE when first- and second generation DES were analyzed separately. Conclusion. Despite higher risk profile, women treated with DES have similar outcomes as males in 1-year follow-up. However there is, an increased risk of in-hospital bleedings in women.     

BetaAPP and furin mRNA concentrates in immature senile plaques in the brain of Alzheimer patients

This study examined the possibility that in Alzheimer disease (AD) beta-amyloid precursor protein (betaAPP) mRNA is delivered to senile plaques (SPs) via dendritic processes. BetaAPP mRNA was detected in SPs by in situ hybridization, using a 1.4-kb cRNA in which both [35S]-UTP and [35S]-CTP were incorporated together. The betaAPP mRNA was compared with that of furin, a proteolytic enzyme putatively involved in betaAPP processing, and its orthologue proprotein convertase PCI served as a control. Human presenile AD cases with mostly immature SPs and AD cases generally with mature SPs were analyzed. To decrypt SPs after hybridization, brain sections were stained with thioflavin S. To establish relationships between the density of dystrophic fibers, the degree of plaque maturation, and the concentration of mRNA in SPs, the plaque maturity markers Abeta(1-42) and Abeta(1-40) peptides were co-localized with neurofilament protein 200 and compared with microtubule-associated protein 2 (MAP 2). The results suggest that immature, Abeta(1-42)- and dystrophic dendrite-containing SPs (but not mature SPs containing Abeta(1-40) and missing dystrophic dendrites) are capable of concentrating specific mRNAs. Dystrophic dendrites may thus serve as a route for the transport of specific mRNAs from the cell bodies to SPs.     

Integrins in pulmonary inflammatory diseases

Integrins are a family of heterodimeric transmembrane glycoproteins that mediate cell-cell and cell-matrix interactions. They participate in inflammatory reactions mainly by regulation of leukocyte migration, activation and survival. Elevated expression of the cell adhesion molecules, such as VCAM, ICAM and MAdCAM on the lumenal surface of vascular endothelial cells is a critical early event in organ inflammatory processes - including the lung. Adhesive interactions with their counter-receptors on leukocytes, selectins and integrins, result in migration of the leukocytes to the inflammed tissues. Integrins also participate in physiological and pathological reorganization of the lung structure during e.g. pneumonia healing, airway remodeling, angiogenesis, emphysema and pulmonary fibrosis. Agents that could inhibit the function of one or more of these integrins could provide a novel therapeutic strategy targeted to inhibit inflammatory and immune phenomena in the lung.     

Prostanoids and MPO-halide system products as a link between innate and adaptive immunity

and The crosstalk between innate adaptive immunity is regulated by cytokines and complex interactions between cells of the immune system. A variety of endogenous agents are involved in the regulation of the cytokine network. Especially, eicosanoids and ROIs have a great impact on the regulation of cytokine production. Eicosanoids (prostanoids, leukotrienes and lipoxins) are produced mainly by inflammatory cells while their receptors are distributed on the cells of both arms of the immune system. Depending on the predominant prostanoid produced and the profile of prostanoid receptors expression on immune cells, eicosanoids can selectively regulate the production of Th1 and Th2 driven cytokines. Inflammatory cells (neutrophils, macrophages), are also a rich source of large amounts of ROIs. In this paper we have focused on the role of taurine chloramine (TauCl), the physiological product of neutrophil MPO-halide system, in the regulation of immune system. It is well documented that TauCl has pleiotropic effects on the inductive phase of the immune response. TauCl's immunoregulatory properties result from its ability to modulate the production of cytokines and eicosanoids. Finally, we conclude that eicosanoids and ROIs provide an important link between the afferent branches and the innate and adaptive immune response.     

Differential effects of pentoxifylline, a non-specific phosphodiesterase inhibitor, on the production of IL-10, IL-12 p40 and p35 subunits by murine peritoneal macrophages

Pentoxifylline (PTX), a methylxanthine derivative, has been reported to be an effective drug in inhibiting TNF-alpha responses during septic shock. The inhibition of TNF-alpha production seems to be correlated with increased intracellular cAMP levels. PTX also affects the production of other cytokines such as IL-1, IL-6, IL-10, IL-12, and IFN-gamma. However, inhibition, as well as enhancement of cytokine production, has been observed in vitro, depending on the PTX concentration and cell type used.IL-12 is a heterodimeric cytokine that plays an important role in the development of Th1-mediated inflammatory responses. IL-12 along with TNF-alpha and other proinflammatory cytokines has shown to be responsible for the pathological reaction, which may lead to septic shock. For biological activity, the expression of both subunits of IL-12, p35 and p40, is required. Moreover, the p40 chain of IL-12 specifically inhibits the effects of the IL-12 heterodimer.In this study, we investigated the effects of PTX on the production of both proinflammatory (TNF-alpha, IL-6, IL-12) and anti-inflammatory (IL-10) cytokines by murine macrophages (Mφ). We have found that PTX, at concentrations below 100 microg/ml, selectively inhibited the production of TNF-alpha. Forskolin, a cAMP-elevating agent, similarly affected the production of the cytokines tested. However, at higher concentrations, PTX inhibited the production of TNF-alpha, IL-10, and IL-12 p35, but surprisingly, PTX enhanced the production of IL-12 p40. Concentrations of IL-10 were negatively correlated with the concentrations of IL-12 p40 subunit. These results further confirm the relevance of the use of PTX in clinical trials of immunological disorders characterised by inappropriate Th1 type immune responses.