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FEBRUARY 2013 AB44 Abstracts S A T U R D A Y 159 Effect of Cholesterol Depletion On Interleukin-8 Production in Human Respiratory Epithelial Cells Min Jung Kim, MD, Jung Yeon Hong, Kyung Eun Lee, PhD, Hwan Soo Kim, MD, Yoon Ki Han, MD, Hye Mi Jee, MD, Kyung Won Kim, MD, PhD, Myung Hyun Sohn, MD, PhD, Kyu-Earn Kim, MD, PhD; Yonsei University College of Medicine, Seoul, Korea, Yonsei University School of Medicine, Seoul, Korea, CHA University School of Medicine, Seongnam, Korea. RATIONALE: Lipid rafts in epithelial cell membrane plays multifunctions, including components of immune system and important mediators in inflammatory process. But the role of cholesterol, composing lipid rafts, has not been described in the inflammatory response. The aim of this study is to investigate the effect of cholesterol depletion to inflammatory process via expression of interleukin (IL)-8 in airway epithelial cells. METHODS: The human epithelial-like lung carcinoma cell line(A 549) was treated with 0.5% methyl-b-cyclodextrin as a selective cholesterol extractor. IL-8 levels were assessed by enzyme-linked immunosorbent assay (ELISA) and rechecked after cholesterol repletion. Mitogen-activated protein kinase (MAPK) inhibitors were used to find upstream signaling pathway for IL-8 production in cholesterol-depleted cells. RESULTS: IL-8 production in cholesterol-depleted epithelial cells increased in a time-dependent manner. The maximum production of IL-8 recorded at 24 hwas almost 3.5 timesmore than control cells. In addition, it reversed after cholesterol repletion. And IL-8 production decreased followed by pretreatment with extracellular signal-regulated kinase (ERK) inhibitor U0126, but not with JNK inhibitor II or p38 MAPK inhibitor SB202190. CONCLUSIONS: These results suggested that inflammatory responses could be increased in cholesterol-depleted cells, and it was regulated by MAPK signaling system, predominantly by ERK pathway. We concluded that lipid component in airway epithelial cells may play a role in inflammatory process.

Rationale Early sensitization to outdoor aeroallergens such as tree, weed and grass pollen in infancy is very important in development of seasonal bronchial asthma or allergic rhinitis. There is suggestion that pollen contact during the first six months of life increase the risk of pollen allergy for twenty years or later. The aim of our investigation was to identify the relationship between the sensitization to outdoor aeroallergens and the month of birth in childhood respiratory allergic disorders. Methods Seventy tree seasonal allergic rhinitis and bronchial asthmatic children were enrolled for this study, and skin prick test was done for each patient to detect the sensitized allergens. Ragweed, mugwort, alder, hazelnut, elm, willow, birch, beech, oak, plane tree, orchard and timothy grass were used for outdoor aeroallergens. The relative risk (RR) for development of hypersensitivity to outdoor aeroallergen in certain month born children was calculated. Results We found that relative risk of immediate hypersensitivity to each outdoor aeroallergen was dependent on the month of birth. Tree pollen was the most common sensitizing allergen in children who were born in May (RR=1.91, p=0.03), weed pollen was in September born children (RR=2.07, p=0.03), and grass pollen was in June born children (RR=3.72, p=0.02). Conclusions Exposure in early infancy to outdoor aeroallergens is an important risk factor of the subsequent development of bronchial asthma and allergic rhinitis.