Won Il Heo

Involvement of the MAPK and PI3K pathways in chitinase 3-like 1-regulated hyperoxia-induced airway epithelial cell death.

BACKGROUND Exposure to 100% oxygen causes hyperoxic acute lung injury characterized by cell death and injury of alveolar epithelial cells. Recently, the role of chitinase 3-like 1 (CHI3L1), a member of the glycosyl hydrolase 18 family that lacks chitinase activity, in oxidative stress was demonstrated in murine models. High levels of serum CHI3L1 have been associated with various diseases of the lung, such as asthma, chronic obstructive pulmonary disease, and cancer. However, the role of CHI3L1 in human airway epithelial cells undergoing oxidative stress remains unknown. In addition, the signaling pathways associated with CHI3L1 in this process are poorly understood. PURPOSE In this study, we demonstrate the role of CHI3L1, along with the MAPK and PI3K signaling pathways, in hyperoxia-exposed airway epithelial cells. METHOD The human airway epithelial cell line, BEAS-2B, was exposed to >95% oxygen (hyperoxia) for up to 72h. Hyperoxia-induced cell death was determined by assessing cell viability, Annexin-V FITC staining, caspase-3 and -7 expression, and electron microscopy. CHI3L1 knockdown and overexpression studies were conducted in BEAS-2B cells to examine the role of CHI3L1 in hyperoxia-induced apoptosis. Activation of the MAPK and PI3K pathways was also investigated to determine the role of these signaling cascades in this process. RESULTS Hyperoxia exposure increased CHI3L1 expression and apoptosis in a time-dependent manner. CHI3L1 knockdown protected cells from hyperoxia-induced apoptosis. In contrast, CHI3L1 overexpression promoted cell death after hyperoxia exposure. Finally, phosphorylation of ERK1/2, p38, and Akt were affected by CHI3L1 knockdown. CONCLUSION This study indicates that CHI3L1 is involved in hyperoxia-induced cell death, suggesting that CHI3L1 may be one of several cell death regulators influencing the MAPK and PI3K pathways during oxidative stress in human airway epithelial cells.

Involvement of IL-10 Gene Promoter Polymorphisms in the Susceptibility for Childhood Asthma

Asthma and atopy have a complex background that may result from the interaction of genes and the environment. Interleukin (IL)-10 is known to play various roles in immune-regulating and anti-inflammatory responses. The aim of this study was to evaluate the possible effect of the IL-10 promoter polymorphisms on susceptibility to childhood asthma. We recruited 333 patients with atopic asthma, 55 with nonatopic asthma, and 248 normal controls. We performed a genetic association study of three genetic polymorphisms (IL-10 –1082A>G, IL-10 –819T>C, and IL-10 –592A>C) of the IL-10 promoter. There was no difference between atopic asthma, nonatopic asthma, and normal controls with respect to allele, genotype, or haplotype frequencies of these IL-10 polymorphisms. However, the −1082A>G polymorphism and ATA haplotype in the IL-10 promoter gene were associated with airway hyper responsiveness (AHR) and the –819T>C, –592A>C, and ATA and ACC haplotypes were also shown to be related to serum eosinophil cationic protein (ECP). Our results suggest that the polymorphisms within the IL-10 promoter may have a disease-modifying effect in the asthmatic airway.

Association of genetic variation in chitotriosidase with atopy in Korean children

BACKGROUND The atopic diseases, which are the most common chronic diseases of childhood, are complex genetic diseases that involve the contribution of multiple genetic factors to disease pathophysiology. Chitotriosidase is involved in innate immunity, but the association of chitotriosidase with allergic diseases remains unclear. OBJECTIVE To examine the contribution of genetic variation of the chitotriosidase-encoding gene CHIT1 to atopic phenotypes in a Korean cohort of children. METHODS We identified CHIT1 variations in a Korean population and conducted association analyses using 295 atopic and 242 nonatopic children. An independent replication study was performed using DNA samples from 148 atopic and 243 nonatopic children. All children were unrelated. We performed Western blot analysis in each genotype in vitro to see whether the CHIT1 A442G variation affects the final protein expression levels. RESULTS In the case-control association analysis, atopy was significantly associated with a single A442G (rs1065761) polymorphism in CHIT1 (odds ratio = 1.32, P = .01). Children with the c.442G risk allele had significantly higher blood eosinophils (P = .001), total serum IgE (P = .007), and eosinophil cationic protein (P = .02) levels. The results of the replication stage analysis confirmed a significant association between the A442G polymorphism and childhood atopy. The joint analysis of the exploratory and replication studies displayed a stronger significant association. The relative protein expression levels of chitotriosidase were significantly higher in both cell lysate and media with the G transfection compared with the wild type. CONCLUSION These results indicate that the nonsynonymous A442G polymorphism in CHIT1 is associated with risk of atopy.

The role of interleukin-17 in mouse models of atopic dermatitis and contact dermatitis.

Atopic dermatitis (AD) and contact dermatitis (CD) are both T cell‐mediated eczematous disorders. Interleukin (IL)‐17, expressed by T helper (Th)17 cells, is involved in recruitment of inflammatory cells into AD and CD skin.

Production of Egg Yolk Antibodies Specific to House Dust Mite Proteins

Purpose House dust mites (HDMs) are an important source of indoor allergens associated with asthma, rhinitis and atopic dermatitis. Chicken immunoglobulin (Ig) Y is known to be a good alternative to mice and rabbit antibody production. In this study, we produced IgYs specific to HDMs and investigated their IgE immunoreactivities. Materials and Methods Total IgYs were isolated from the yolks of White Leghorn hens immunized with either Dermatophagoides pteronyssinus or D. farinae protein extract. Control antibodies were separated from the yolks of immunized hens with phosphate buffered saline. IgYs specific to HDMs were analyzed using enzyme-linked immunosorbent assay and Western blotting analysis. Results The concentration of egg IgY specific to D. farinae in an immunized hen increased and the highest achieved was 661.3 ug/mg (per an egg) on day 47, compared with 760 ug/mg IgY specific to D. pteronyssinus on day 16. The D. pteronyssinus or D. farinae-specific IgY was detected by binding of each mite proteins, and their immunoreactivities were elevated dependent of the specific IgY concentration. Conclusion IgY specific to HDMs may be a promising antibody for immunological diagnosis as well as identification of possible resistance relating to HDM allergy.

520 Involvement of Il-10 Gene Promoter Polymorphisms in the Susceptibility for Childhood Asthma

Background Asthma and atopy have a complex background which may result from the interaction of genes and environments. Interleukin (IL)-10 is known to play various roles in immune-regulating and anti-inflammatory responses. The aim of this study was to evaluate the possible effect of the IL-10 promoter polymorphisms on susceptibility to childhood asthma. Methods We recruited 333 patients with atopic asthma, 55 with non-atopic asthma, and 248 normal controls. We performed a genetic association study of 3 genetic polymorphisms (IL-10–1082A>G, IL-10 –819T>C, –592A>C) of the IL-10 promoter. Results There was no difference between atopic asthma, non-atopic asthma and normal controls in allele, genotype or haplotype frequencies of these IL-10 polymorphisms. However, the –1082A>G polymorphism and ATA haplotype in the IL-10 promoter gene were associated with airway hyperresponsiveness (AHR) and the –819T>C, –592A>C, and ATA and ACC haplotypes were also shown to be related with serum eosinophil cationic protein (ECP). Conclusions Our results suggest that the polymorphisms within the IL-10 promoter may have a disease-modifying effect in asthmatic airway.