| 1. |
- James, Anna, et al.
(författare)
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The influence of aspirin on release of eoxin C4, leukotriene C4 and 15-HETE, in eosinophilic granulocytes isolated from patients with asthma
- 2013
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Ingår i: International Archives of Allergy and Immunology. - : S. Karger AG. - 1018-2438 .- 1423-0097. ; 162:2, s. 135-42
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Tidskriftsartikel (refereegranskat)abstract
- Background: The effect of aspirin on the release of key arachidonic acid metabolites in activated eosinophils from subjects with aspirin-intolerant asthma (AIA) has not been investigated previously, despite the characteristic eosinophilia in AIA. Methods: Peripheral blood eosinophils were isolated from four groups of subjects: healthy volunteers (HV; n = 8), mild asthma (MA; n = 8), severe asthma (SA; n = 9) and AIA (n = 7). In the absence or presence of lysine-aspirin, eosinophils were stimulated with arachidonic acid or calcium ionophore to trigger the 15-lipoxygenase-1 (15-LO) and 5-lipoxygenase (5-LO) pathways, respectively. 15(S)-hydroxy-eicosatetraenoic acid (15-HETE) and eoxin C4 (EXC4) were measured as 15-LO products and leukotriene (LT)C4 as a product of the 5-LO pathway. Results: Activated eosinophils from patients with SA and AIA produced approximately five times more 15-HETE than eosinophils from HV or MA patients. In the presence of lysine-aspirin, eosinophils from AIA, MA and SA patients generated higher levels of 15-HETE than in the absence of lysine-aspirin. Furthermore, in the presence of lysine-aspirin, formation of EXC4 was also significantly increased in eosinophils from AIA patients, and LTC4 synthesis was increased both in AIA and SA patients. Conclusions: Taken together, this study shows an increased release of the recently discovered lipid mediator EXC4, as well as the main indicator of 15-LO activity, 15-HETE, in activated eosinophils from severe and aspirin-intolerant asthmatics, and also elevated EXC4 and LTC4 formation in eosinophils from AIA patients after cellular activation in the presence of lysine-aspirin. The findings support a pathophysiological role of the 15-LO pathway in SA and AIA.
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| 2. |
- Brunnström, Åsa, et al.
(författare)
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On the biosynthesis of 15-HETE and eoxin C-4 by human airway epithelial cells
- 2015
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Ingår i: Prostaglandins & other lipid mediators. - : Elsevier BV. - 1098-8823 .- 2212-196X. ; 121, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence indicate that 15-lipoxygenase type 1 (15-LO-1) plays a pathophysiological role in asthma. The aim for this study was to investigate the 15-LO-1 expression and activity in primary human airway epithelial cells cultivated on micro-porous filters at air liquid interface. Incubation of human airway epithelial cells with arachidonic acid led to the formation of 15(S)-hydroxy-eicosatetraenoic acid (15-HETE) and exposing the cells to bacteria or physical injury markedly increased their production of 15-HETE. The cells were also found to convert arachidonic acid to eoxin C-4 (EXC4). Subcellular fractionation revealed that the conversion of EXA(4) to EXC4 was catalyzed by a soluble glutathione transferase (GST). The GST P1-1 enzyme was found to possess the highest activity of the investigated soluble GSTs. Following IL-4 treatment of airway epithelial cells, microarray analysis confirmed high expression of 15-LO-1 and GST P1-1, and immunohistochemical staining of bronchial biopsies revealed co-localization of 15-LO-1 and GST P1-1 in airway epithelial cells. These results indicate that respiratory infection and cell injury may activate the 15-LO pathway in airway epithelial cells. Furthermore, we also demonstrate that airway epithelial cells have the capacity to produce EXC4.
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| 3. |
- Gulliksson, Magdalena, et al.
(författare)
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Expression of 15-lipoxygenase type-1 in human mast cells
- 2007
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 1878-2434. ; 1771:9, s. 1156-65
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells play a key role in the pathophysiology of asthma. These cells exert their effector functions by releasing a variety of proinflammatory and immunoregulatory compounds. Mast cells infiltrate the bronchial epithelium and smooth muscle to a higher degree in patients with asthma compared to control subjects. 15-Lipoxygenase type-1 (15-LO-1) is a prooxidant enzyme which is expressed in asthmatic lungs leading to formation of pro- and anti-inflammatory mediators. Here we report that interleukin-4 (IL-4) induced the expression of 15-LO-1 in human cord blood derived mast cells (CBMC) as demonstrated by RT-PCR, western blot and immunocytochemistry. The major metabolite of arachidonic acid formed via the 15-LO pathway in IL-4 treated CBMC was identified as 15-ketoeicosatetraenoic acid (15-KETE, also named 15-oxo-ETE) with smaller amounts of 15-hydroxyeicosatetraenoic acid (15-HETE) as identified by HPLC and mass spectrometry (MS/MS). Furthermore, immunohistochemical stainings demonstrated the expression of 15-LO-1 in mast cells in lung and skin in vivo. Osmotic activation of CBMC with mannitol resulted in activation of the 15-LO-1 pathway. In conclusion, the expression of 15-LO-1 and release of 15-LO-1 derived products by mast cells may contribute to the role of these cells in asthma and other inflammatory diseases.
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