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author:("Lee, Chun gen")
1.  Modifiers of TGF-β1 effector function as novel therapeutic targets of pulmonary fibrosis 
Pulmonary fibrosis is a fatal progressive disease with no effective therapy. Transforming growth factor (TGF)-β1 has long been regarded as a central mediator of tissue fibrosis that involves multiple organs including skin, liver, kidney, and lung. Thus, TGF-β1 and its signaling pathways have been attractive therapeutic targets for the development of antifibrotic drugs. However, the essential biological functions of TGF-β1 in maintaining normal immune and cellular homeostasis significantly limit the effectiveness of TGF-β1-directed therapeutic approaches. Thus, targeting downstream mediators or signaling molecules of TGF-β1 could be an alternative approach that selectively inhibits TGF-β1-stimulated fibrotic tissue response while preserving major physiological function of TGF-β1. Recent studies from our laboratory revealed that TGF-β1 crosstalk with epidermal growth factor receptor (EGFR) signaling by induction of amphiregulin, a ligand of EGFR, plays a critical role in the development or progression of pulmonary fibrosis. In addition, chitotriosidase, a true chitinase in humans, has been identified to have modulating capacity of TGF-β1 signaling as a new biomarker and therapeutic target of scleroderma-associated pulmonary fibrosis. These newly identified modifiers of TGF-β1 effector function significantly enhance the effectiveness and flexibility in targeting pulmonary fibrosis in which TGF-β1 plays a significant role.
doi:10.3904/kjim.2014.29.3.281
PMCID: PMC4028515  PMID: 24851060
Transforming growth factor beta1; Pulmonary fibrosis; Response modifiers; Amphiregulin; Chitotriosidase
2.  IL-18 Induces Emphysema and Airway and Vascular Remodeling via IFN-γ, IL-17A, and IL-13 
Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, alveolar destruction, and airway and vascular remodeling. However, the mechanisms that lead to these diverse alterations have not been defined.
Objectives: We hypothesized that IL-18 plays a central role in the pathogenesis of these lesions.
Methods: We generated and characterized lung-specific, inducible IL-18 transgenic mice.
Measurements and Main Results: Here we demonstrate that the expression of IL-18 in the mature murine lung induces inflammation that is associated with the accumulation of CD4+, CD8+, CD19+, and NK1.1+ cells; emphysema; mucus metaplasia; airway fibrosis; vascular remodeling; and right ventricle cardiac hypertrophy. We also demonstrate that IL-18 induces type 1, type 2, and type 17 cytokines with IFN-γ–inhibiting macrophage, lymphocyte, and eosinophil accumulation while stimulating alveolar destruction and genes associated with cell cytotoxicity and IL-13 and IL-17A inducing mucus metaplasia, airway fibrosis, and vascular remodeling. We also highlight interactions between these responses with IL-18 inducing IL-13 via an IL-17A–dependent mechanism and the type 1 and type17/type 2 responses counterregulating each another.
Conclusions: These studies define the spectrum of inflammatory, parenchymal, airway, and vascular alterations that are induced by pulmonary IL-18; highlight the similarities between these responses and the lesions in COPD; and define the selective roles that type 1, type 2, and type 17 responses play in the generation of IL-18–induced pathologies.
doi:10.1164/rccm.201108-1545OC
PMCID: PMC3373071  PMID: 22383501
IL-18; chronic obstructive pulmonary disease; airway fibrosis; mucus metaplasia; vascular remodeling
3.  Role of Breast Regression Protein–39 in the Pathogenesis of Cigarette Smoke–Induced Inflammation and Emphysema 
The exaggerated expression of chitinase-like protein YKL-40, the human homologue of breast regression protein–39 (BRP-39), was reported in a number of diseases, including chronic obstructive pulmonary disease (COPD). However, the in vivo roles of YKL-40 in normal physiology or in the pathogenesis of specific diseases such as COPD remain poorly understood. We hypothesized that BRP-39/YKL-40 plays an important role in the pathogenesis of cigarette smoke (CS)–induced emphysema. To test this hypothesis, 10-week-old wild-type and BRP-39 null mutant mice (BRP-39−/−) were exposed to room air (RA) and CS for up to 10 months. The expression of BRP-39 was significantly induced in macrophages, airway epithelial cells, and alveolar Type II cells in the lungs of CS-exposed mice compared with RA-exposed mice, at least in part via an IL-18 signaling–dependent pathway. The null mutation of BRP-39 significantly reduced CS-induced bronchoalveolar lavage and tissue inflammation. However, CS-induced epithelial cell apoptosis and alveolar destruction were further enhanced in the absence of BRP-39. Consistent with these findings in mice, the tissue expression of YKL-40 was significantly increased in the lungs of current smokers compared with the lungs of ex-smokers or nonsmokers. In addition, serum concentrations of YKL-40 were significantly higher in smokers with COPD than in nonsmokers or smokers without COPD. These studies demonstrate a novel regulatory role of BRP-39/YKL-40 in CS-induced inflammation and emphysematous destruction. These studies also underscore that maintaining physiologic concentrations of YKL-40 in the lung is therapeutically important in preventing excessive inflammatory responses or emphysematous alveolar destruction.
doi:10.1165/rcmb.2010-0081OC
PMCID: PMC3135840  PMID: 20656949
YKL-40/BRP-39; COPD; emphysema; cigarette smoke
4.  An Essential Regulatory Role of Downstream of Kinase-1 in the Ovalbumin-Induced Murine Model of Asthma 
PLoS ONE  2012;7(4):e34554.
The downstream of kinase (DOK)-1 is involved in the protein tyrosine kinase (PTK) pathway in mast cells, but the role of DOK-1 in the pathogenesis of asthma has not been defined. In this study, we have demonstrated a novel regulatory role of DOK-1 in airway inflammation and physiologic responses in a murine model of asthma using lentiviral vector containing DOK-1 cDNA or DOK-1-specific ShRNA. The OVA-induced inflammatory cells, airway hyperresponsiveness, Th2 cytokine expression, and mucus response were significantly reduced in DOK-1 overexpressing mice compared to OVA-challenged control mice. The transgenic introduction of DOK-1 significantly stimulated the activation and expression of STAT-4 and T-bet, while impressively inhibiting the activation and expression of STAT-6 and GATA-3 in airway epithelial cells. On the other hand, DOK-1 knockdown mice enhanced STAT-6 expression and its nuclear translocation compared to OVA-challenged control mice. When viewed in combination, our studies demonstrate DOK-1 regulates allergen-induced Th2 immune responses by selective stimulation and inhibition of STAT-4 and STAT-6 signaling pathways, respectively. These studies provide a novel insight on the regulatory role of DOK-1 in allergen-induced Th2 inflammation and airway responses, which has therapeutic potential for asthma and other allergic diseases.
doi:10.1371/journal.pone.0034554
PMCID: PMC3326039  PMID: 22514638

Results 1-4 (4)