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author:("Lee, Chun gen")
1.  The Chitinase-like Proteins Breast Regression Protein-39 and YKL-40 Regulate Hyperoxia-induced Acute Lung Injury 
Rationale: Prolonged exposure to 100% O2 causes hyperoxic acute lung injury (HALI), characterized by alveolar epithelial cell injury and death. We previously demonstrated that the murine chitinase-like protein, breast regression protein (BRP)–39 and its human homolog, YKL-40, inhibit cellular apoptosis. However, the regulation and roles of these molecules in hyperoxia have not been addressed.
Objectives: We hypothesized that BRP-39 and YKL-40 (also called chitinase-3–like 1) play important roles in the pathogenesis of HALI.
Methods: We characterized the regulation of BRP-39 during HALI and the responses induced by hyperoxia in wild-type mice, BRP-39–null (−/−) mice, and BRP-39−/− mice in which YKL-40 was overexpressed in respiratory epithelium. We also compared the levels of tracheal aspirate YKL-40 in premature newborns with respiratory failure.
Measurements and Main Results: These studies demonstrate that hyperoxia inhibits BRP-39 in vivo in the murine lung and in vitro in epithelial cells. They also demonstrate that BRP-39−/− mice have exaggerated permeability, protein leak, oxidation, inflammatory, chemokine, and epithelial apoptosis responses, and experience premature death in 100% O2. Lastly, they demonstrate that YKL-40 ameliorates HALI, prolongs survival in 100% O2, and rescues the exaggerated injury response in BRP-39−/− animals. In accord with these findings, the levels of tracheal aspirate YKL-40 were lower in premature infants treated with hyperoxia for respiratory failure who subsequently experienced bronchopulmonary dysplasia or death compared with those that did not experience these complications.
Conclusions: These studies demonstrate that hyperoxia inhibits BRP-39/YKL-40, and that BRP-39 and YKL-40 are critical regulators of oxidant injury, inflammation, and epithelial apoptosis in the murine and human lung.
doi:10.1164/rccm.200912-1793OC
PMCID: PMC2970863  PMID: 20558631
BRP-39; YKL-40; hyperoxygen; BPD; HALI
2.  Endogenous IL-11 Signaling Is Essential in Th2- and IL-13–Induced Inflammation and Mucus Production 
IL-11 and IL-11 receptor (R)α are induced by Th2 cytokines. However, the role(s) of endogenous IL-11 in antigen-induced Th2 inflammation has not been fully defined. We hypothesized that IL-11, signaling via IL-11Rα, plays an important role in aeroallergen-induced Th2 inflammation and mucus metaplasia. To test this hypothesis, we compared the responses induced by the aeroallergen ovalbumin (OVA) in wild-type (WT) and IL-11Rα–null mutant mice. We also generated and defined the effects of an antagonistic IL-11 mutein on pulmonary Th2 responses. Increased levels of IgE, eosinophilic tissue and bronchoalveolar lavage (BAL) inflammation, IL-13 production, and increased mucus production and secretion were noted in OVA-sensitized and -challenged WT mice. These responses were at least partially IL-11 dependent because each was decreased in mice with null mutations of IL-11Rα. Importantly, the administration of the IL-11 mutein to OVA-sensitized mice before aerosol antigen challenge also caused a significant decrease in OVA-induced inflammation, mucus responses, and IL-13 production. Intraperitoneal administration of the mutein to lung-specific IL-13–overexpressing transgenic mice also reduced BAL inflammation and airway mucus elaboration. These studies demonstrate that endogenous IL-11R signaling plays an important role in antigen-induced sensitization, eosinophilic inflammation, and airway mucus production. They also demonstrate that Th2 and IL-13 responses can be regulated by interventions that manipulate IL-11 signaling in the murine lung.
doi:10.1165/rcmb.2008-0053OC
PMCID: PMC2586049  PMID: 18617680
IL-11; mutein; airway inflammation; mucus; IL-13

Results 1-2 (2)