Fibronectin differentially regulates eosinophil migration, polarization and signaling via the p38 MAPK pathway

Abstract

VOLUME 109, NUMBER 1 found activation of signal transducer and activator of transcription (STAT)6, known to become activated through IL-4, following stimulation of human intestinal mast cells with 10 ng/ml IL-4 for 10 min, but we did not detect mRNA expression ofTh2 cytokines following short term stimulation with IL-4 (up to 6 h). Consistently, STAT6 was also activated by IL-13, which is known to share the IL-4R alpha chain, but cytokine expression was not affected by IL-13. Noteworthy, the cytokine expression was also not changed after 14 d of culture of human intestinal mast cells the presence of IL13. We found that the production of Th2 cytokines was dependent on extracellnlar signal-regulated protein kinase (Erk)l/2, a mitogen activated protein kinase (MAPK). Erkl/2 was not activated after stimulation with IL4 for 10 rain but was slightly activated mast cells during culture with SCF and IL-4 contrast to culture with SCF alone. In summary, our data suggest that MAPK, but not STAT6, is involved the IL-4 dependent long term alteration of the mast cell cytokine profile. ' ~ N ~ Fibronectin Differentially Regulates Eosinophil Migration, I ~ I ~ I F Polarization and Signaling via the p38 MAPK Pathway Laura L Dziadzio, Alison Holub, Scott Anderson, .lake Byrnes, William W Busse, Anna Huttenlocher University of Wisconsin, Madison, WI Although eosinophils are a major component of the inflammatory response persistent airway inflammation asthma, the factors that determine their presence or retention the lung have not been fully defined. Elevated levels of fibronectin have been observed the bronchoalveolar lavage fluids of patients with asthma 48 hrs after antigen challenge and correlate with the number of eosinophils retained the airway. The recruitment of eosinophils to areas of inflammation requires regulated interaction between cell surface receptors and ligands, including the activity of the Rho family of GTPases, such as p38MAPkinase and ERK. Thus, we hypothesize that the migration of eosinophils to areas of inflammation, and their ultimate adherence, may be modulated by fibronectin concentration and intracellular signaling. To study this possibility, peripheral blood eosinophils were isolated from subjects with mild asthma and were plated on increasing amounts of fibronectin and activated with fMLP or eotaxin. Western blotting was performed and then probed for phospho-p38MAPK, phospho-ERK, p38MAPK and ERK. Time-lapse videomicroscopy was also performed on eosinophils to observe adhesion, spreading and migration. High-density fibronectin inhibited eosinophil spreading and migration, but not eosinophil adhesion cells activated with fMLP or eotaxin. In contrast, cells treated with IL-5/RANTES, eosinophil adhesion and migration were inhibited at high fibronectin density. Activation of p38MAPK was also inhibited at high fibronectin density the presence of fMLP and eotaxin, while ERK activity persisted, independent of fibronectin concentration. These findings suggest that high-density fibronectin, as found BAL fluid asthma, may retain eosinophils the airway with associated down-regulation of p38MAPK. Collectively, our data suggest that fibronectin may contribute to the retention of inflammatory cells by regulating eosinophil polarization and migration and modulating intracellular signaling pathways by the p38MAP. l n n n Assessment of Atopy Textile Industry Workers: Compari1,01,01,0 son of Two Methods Jos~ A Ferreira, Jos~ C Torres Costa, Eunice D Castro, Marianela Vaz Hospital S Jo~o, Porto, Portugal INTRODUCTION: Of the occupational respiratory diseases, occupational asthma has the highest morbidity and epidemiologic significance. Various factors are implied its etiology, namely atopy, bronchial hyperreactivity, smoking status, age and proximity to the allergenic source. Skin prick tests (SPT) are considered the gold standard for demonstration of atopy however due to the difficulty its execution epidemiologic studies, various authors have used in vitro tests with good results. OBJECTIVE: To compare the efficacy of two multiallergenic in vitro tests (MAT) (Phadiatop ® and Stallertest ®) with the SPT the assessment of atopy textile industry workers. POPULATION AND METHODS: 462 cotton textile workers (M: 233; F: 229), mean age: 45 ___ 8.4 years. Mean exposure time to cotton dust: 23 _+ 9.7 years. From the 462 workers, 144 presented respiratory symptoms (asthma: 60; bissinosis: 32; chronic cough: 13; COPD: 11 and rhinitis: 103). Smokers: 104. Clinical evaluation, S PT, lung function tests, total IgE and the two MAT: Phadiatop ® (189 workers) and Stallertest ® (273 workers) were performed. RESULTS: Total IgE values were higher the atopic group: 161.2 +_. 215 vs 80.9 _+ 133 kU/L; p<0.0001. SPT were positive 88 (19.1%) and MAT 68 (16.9%) of workers. Compared with the SPT, MAT presented global sensitivity and specificity of: 44.5% and 90.3% (Phadiatop ®) and 34.4% and 94.3% (Stallertest®). Analysing only the symptomatic group, sensitivity and specificity improved to 83.3% and 93% (Phadiatop ®) and to 75% and 95.3% (Stallertest®). CONCLUSION: Due to the low efficiency of the two MAT this population, we do not recommend the use of in vitro tests substitution of SPT the assessment of atopy epidemiological studies of occupational