Jung Yeon Hong

Increased serum thymic stromal lymphopoietin in children with atopic dermatitis

Lee EB, Kim KW, Hong JY, Jee HM, Sohn MH, Kim K‐E. Increased serum thymic stromal lymphopoietin in children with atopic dermatitis.
Pediatr Allergy Immunol 2010: 21: e457–e460.
© 2010 John Wiley & Sons A/S

Chitinase Activates Protease-Activated Receptor-2 in Human Airway Epithelial Cells

Mammalian chitinase released by airway epithelia is thought to be an important mediator of disease manifestation in an experimental model of asthma. However, the intracellular signaling mechanisms engaged by exogenous chitinase in human airway epithelial cells are unknown. Here, we investigated the direct effects of exogenous chitinase from Streptomyces griseus on Ca(2+) signaling in human airway epithelial cells. Spectrofluorometry was used to measure intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura-2-AM-loaded cells. S. griseus chitinase induced dose-dependent [Ca(2+)](i) increases in normal human bronchial epithelial cells and promoted [Ca(2+)](i) oscillations in H292 cells. Chitinase-induced [Ca(2+)](i) oscillations were independent of extracellular Ca(2+), suggesting that the observed [Ca(2+)](i) increases were due to Ca(2+) release from intracellular stores. Accordingly, after depleting endoplasmic reticulum (ER) Ca(2+) with the ER Ca(2+) ATPase inhibitor, thapsigargin, chitinase-mediated [Ca(2+)](i) increases were abolished. Treatment with the phospholipase C (PLC) inhibitor U73122 or the 1, 4, 5-trisinositolphosphate (IP(3)) receptor inhibitor 2-APB attenuated chitinase-induced [Ca(2+)](i) increases. Desensitization of protease-activated receptor-2 (PAR-2) by repetitive agonist stimulation or siRNA-mediated PAR-2 knock-down revealed that chitinase-mediated [Ca(2+)](i) increases were exclusively mediated by PAR-2 activation. Finally, chitinase was found to cleave a model peptide representing the cleavage site of PAR-2 and enhanced IL-8 production. These results indicate that exogenous chitinase is a potent proteolytic activator of PAR-2 that can directly induce PLC/IP(3)-dependent Ca(2+) signaling in human airway epithelial cells.

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.

Chitinase Induce the Release of IL-8 in Human Airway Epithelial Cells, Via Ca2+-dependent PKC and ERK Pathways

Chitinases are produced in significant quantities by hosts defending against infections with chitin‐containing organisms. However, little is known about the immune response of exogenous chitinase in human epithelial cells. IL‐8 has been suggested to have a role in the pathogenesis of the allergenic inflammation of bronchial asthma. We examined whether Streptomyces griseus (S. griseus) chitinase‐induced IL‐8 on airway epithelium and identified the involvement of intracellular signalling pathways. H292 cells were treated with S. griseus chitinase with different concentrations and times. The IL‐8 levels were determined by specific human IL‐8 enzyme‐linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction. Using a series of pharmacological inhibitors, we examined the upstream signalling pathway responsible for IL‐8 expression in response to S. griseus chitinase. Cells exposed to S. griseus chitinase showed higher level of IL‐8 protein production and mRNA expression. Cells stimulated by S. griseus chitinase resulted in the activation of protein kinase C (PKC), extracellular signal‐regulated kinase (ERK) and nuclear factor kappa‐B (NF‐kB) pathways. Inhibitors of Ca2+‐dependent PKC (Ro‐31‐8220, calphostin C and Gő6976) significantly abolished chitinase‐induced expression of IL‐8. However, Ca2+‐independent PKC inhibitor (rottlerin) did not inhibit IL‐8 expression. Through ERK inhibitor (U0126) and NF‐kB inhibitor (caffeine acid phenethyl ester) treatment, it was proven that ERK and NF‐kB regulated chitinase‐induced IL‐8 expression. We concluded that S. griseus chitinase‐induced IL‐8 expression was regulated by the activation of Ca2±‐dependent PKC, ERK and NF‐kB in human airway epithelial cells.

Modulation of IL-8 boosted by Mycoplasma pneumoniae lysate in human airway epithelial cells.

Mycoplasma pneumoniae, a major cause of community-acquired pneumonia, has been recognized as a trigger for asthma inception and exacerbation. The epithelial cells on the respiratory tract parasitized by M. pneumoniae exhibit a number of cytopathic effects as a result of local inflammation and stimulated host immune response. We investigated the interactions of signaling molecules regulating the release of IL-8 by the direct stimulation of M. pneumoniae lysate (MPL) in human airway epithelial cells. In human airway epithelial cells, MPL-induced IL-8 proteins were decreased by monoclonal anti-TLR2 antibody in a dose-dependent fashion, and significantly blocked by siRNA TLR2. The pharmacologic inhibitors of ERK, U0126 and PD98059, effectively reduced IL-8 expression and the active forms of ERK signaling molecules, as detected by anti-phosphorylated p44/42 antibody. The region spanning from −132 to +41 in the IL-8 promoter demonstrated the highest luciferase activity against MPL and the mutations of NF-κB and NF-IL6 entirely diminished the activity. After investigating transfections of the NF-κB and NF-IL6 reporter vectors, NF-IL6 activation was significantly induced by MPL stimulation, which was considerably decreased by U0126 and monoclonal anti-TLR2 antibody. These results indicate that MPL-induced IL-8 increase is transcriptionally regulated by NF-IL6 more than by NF-κB. Additionally, the activation of NF-IL6 is influenced by TLR2 and ERK signaling pathways in airway epithelial cells.

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.

Pandemic influenza virus, pH1N1, induces asthmatic symptoms via activation of innate lymphoid cells

The pandemic strain of the influenza A virus (pH1N1) in 2009 caused many complications in patients. In this study, we introduce asthmatic symptoms as a complication of pH1N1 infection in children, not having a relationship with asthma history. The aim of this study was to quantify asthmatic symptoms in pH1N1‐infected children and elucidate the underlying mechanisms of airway hyper‐responsiveness (AHR) induced in a murine model of pH1N1 infection.

Sputum pentraxin 3 as a candidate to assess airway inflammation and remodeling in childhood asthma

AbstractPentraxin 3 (PTX3) is a soluble pattern recognition receptor and an acute-phase protein. It has gained attention as a new biomarker reflecting tissue inflammation and damage in a variety of diseases. Aim of this study is to investigate the role of PTX3 in childhood asthma.In total, 260 children (140 patients with asthma and 120 controls) were enrolled. PTX3 levels were measured in sputum supernatants using enzyme-linked immunosorbent assay test. We performed spirometry and methacholine challenge tests and measured the total eosinophil count and the serum levels of total IgE and eosinophil cationic protein (ECP) in all subjects.Sputum PTX3 concentration was significantly higher in children with asthma than in control subjects (P < 0.001). Furthermore, sputum PTX3 levels correlated with atopic status and disease severity among patients with asthma. A positive significant correlation was found between sputum PTX3 and the bronchodilator response (r = 0.25, P = 0.013). Sputum PTX3 levels were negatively correlated with forced expiratory volume in 1 second (FEV1) (r = -0.30, P = 0.001), FEV1/forced vital capacity (FVC) (r = -0.27, P = 0.002), and FEF25–75 (r = -0.392, P < 0.001), which are indicators of airway obstruction and inflammation. In addition, the PTX3 concentration in sputum showed negative correlations with post-bronchodilator (BD) FEV1 (r = -0.25, P < 0.001) and post-BD FEV1/FVC (r = -0.25, P < 0.001), which are parameters of persistent airflow limitation reflecting airway remodeling.Sputum PTX3 levels increased in children with asthma, suggesting that PTX3 in sputum could be a candidate molecule to evaluate airway inflammation and remodeling in childhood asthma.

Relationship between Sputum Clusterin Levels and Childhood Asthma

Clusterin is a sensitive cellular biosensor of oxidative stress and has been studied as a biomarker for inflammation‐associated diseases. Clusterin levels in childhood asthma have not been evaluated.