ABSTRACT
In this study, we investigated the synthesis of lipoxins (LXs) and their anti-inflammatory effects in different human airway epithelial cell culture models. After cell incubation with exogenous 5(S),6(R)-dihydroxy-7,9-trans-11,14-cis-eicosatetraenoic acid, LXA(4) was detected in supernatants of differentiated human bronchial epithelial cells by contrast to non-differentiated cells. Exogenous LXA(4) significantly inhibited tumor necrosis factor-alpha (TNF-alpha)-induced interleukin-8 (IL-8) release in the different epithelial cell types and the potency of inhibition was dependent of the accessibility of the specific LXA(4) receptor, formyl-peptide receptor like-1 (FPRL-1) expressed by all these cells. Immunohistochemistry analysis on human bronchial biopsies showed a high expression of FPRL-1 in the epithelium. Finally, an FPRL-1 receptor antagonist, boc-2 peptide reversed LXA(4) effect on IL-8 generation. Together, these findings indicate that differentiated human bronchial epithelium synthesizes LX in vivo which could have autocrine actions through its specific receptor FPRL-1 to promote resolution of airway inflammation.
Subject(s)
Epithelial Cells/metabolism , Lipoxins/biosynthesis , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Blotting, Western , Bronchi/cytology , Cells, Cultured , Chromatography, High Pressure Liquid , Epithelial Cells/drug effects , Humans , Hydroxyeicosatetraenoic Acids/pharmacology , Immunochemistry , Interleukin-8/biosynthesis , Lipoxins/pharmacology , Receptors, Formyl Peptide/biosynthesis , Receptors, Lipoxin/biosynthesis , Respiratory Mucosa/cytology , Tumor Necrosis Factor-alpha/pharmacologyABSTRACT
BACKGROUND: Lipoxins and 15-epi-lipoxins are lipid mediators that modulate leukocyte trafficking and promote the inflammation resolution. They are produced by different enzymatic pathways. Patients with severe asthma present ongoing airway inflammation despite chronic long-term treatment including oral glucocorticoids. OBJECTIVES: The aim of this study was to assess the presence of proinflammatory and anti-inflammatory mediators in the supernatants of induced sputum. METHODS: Induced sputum supernatants were collected from 10 normal subjects; 12 subjects with mild, 15 with moderate, and 24 with severe asthma; and 13 patients with chronic obstructive pulmonary disease. First, we validated the measurements of IL-8, leukotriene B 4 , lipoxin A 4 , and 15-epi-lipoxin A 4 in these samples. Then we measured these mediators by using immunoenzymatic methods. RESULTS: IL-8 levels were highly increased in patients with severe asthma ( P < .0001), and leukotriene B 4 levels were significantly increased in patients with severe asthma and patients with chronic obstructive pulmonary disease. Lipoxin A 4 was significantly increased in the supernatant obtained from patients with mild asthma ( P < .0001), whereas 15-epi-lipoxin A 4 levels were higher in patients with severe asthma ( P = .05). More interestingly, we found a positive correlation between the level of lipoxin A 4 and IL-8 in patients with mild asthma. CONCLUSION: These results indicate that induced sputum is a suitable method to assess lipoxin and 15-epi-lipoxin measurements in bronchi. The mechanisms involved in the synthesis of these 2 eicosanoid mediators would be helpful to understand better the imbalance between proinflammatory and anti-inflammatory mediators occurring in severe asthma. Lipoxin production involves interaction between lipoxygenases, whereas 15-epi-lipoxin production might involve CytP450 activity.
Subject(s)
Asthma/immunology , Lipoxins/immunology , Sputum/immunology , Adult , Asthma/pathology , Female , Humans , Interleukin-8/analysis , Interleukin-8/biosynthesis , Leukotriene B4/analysis , Leukotriene B4/biosynthesis , Lipoxins/analysis , Lipoxins/biosynthesis , Male , Middle Aged , Pneumonia/immunology , Pulmonary Disease, Chronic Obstructive/immunology , Sputum/cytologyABSTRACT
Enantiopure nitrogen mustards which mimic (L)-carnitine framework are prepared by a multi-step synthesis from the (R)-di-tert-butyl malate and their antitumor properties evaluated.
Subject(s)
Carnitine/analogs & derivatives , Nitrogen Mustard Compounds/chemical synthesis , Nitrogen Mustard Compounds/pharmacology , Antineoplastic Agents, Alkylating/chemistry , Antineoplastic Agents, Alkylating/pharmacology , Humans , Inhibitory Concentration 50 , Malates/chemistry , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, CulturedABSTRACT
Lipoxins, endogenous eicosanoids biosynthetized in vivo at inflammation sites, are potential antiinflammatory mediators. Subjects with severe asthma present chronic inflammation of the airways despite long-term treatment with oral glucocorticoids. Therefore it is of interest to investigate the potential antiinflammatory effects of lipoxin A4 (LXA4) and lipoxin B4 (LXB4) that could attenuate chronic inflammation. In a first time, we detected interleukin (IL)-8 and LXA4 in supernatants of induced sputum. IL-8 was heightened in severe asthma (p = 0.001), whereas high concentrations of lipoxin A4 were present in mild asthma (p = 0.001). We then studied the effects of LXA4 on IL-8 released in vitro. Nanomolar concentrations of LXA4 and LXB4 inhibited the IL-8 released by peripheral blood mononuclear cells from the two groups of patients with asthma: a maximal inhibition of 29.4% (p < 0.01) was observed for patients with mild asthma, and 41.5% inhibition (p < 0.001) for patients with severe asthma at 1 nM and 100 nM LXA4 concentrations, respectively. Polymerase chain reaction analysis indicated that peripheral blood mononuclear cells from patients with asthma expressed the LXA4 receptor mRNA. Moreover, pertussis toxin reversed LXA4- and LXB4-inhibited IL-8 release. These findings suggest that lipoxins have potential antiinflammatory action in asthma.
