Rationale Club cell secretory protein-16 (CC16) is the major secreted product of airway Club cells, but its role in the pathogenesis of COPD is unclear. We measured CC16 airway expression in humans with and without COPD and CC16 function in a cigarette smoke (CS)-induced COPD mice model. Methods Airway CC16 expression was measured in COPD patients, smokers without COPD, and non-smokers. We exposed wild-type (WT) and CC16-/- mice to CS or air for up to 6 months, and measured airway CC16 expression, pulmonary inflammation, alveolar septal cell apoptosis, airspace enlargement, airway MUC5AC expression, small airway remodeling, and pulmonary function. Results Smokers and COPD patients had reduced airway CC16 immunostaining that decreased with increasing COPD severity. Exposing mice to CS reduced airway CC16 expression. CC16-/- mice had greater CS-induced emphysema, airway remodeling, pulmonary inflammation, alveolar cell apoptosis, airway MUC5AC expression, and more compliant lungs than WT mice. These changes were associated with increased nuclear factor-κB (NFκB) activation in CC16-/- lungs. CS-induced acute pulmonary changes were reversed by adenoviral-mediated over-expression of CC16. Conclusions CC16 protects lungs from CS-induced injury by reducing lung NFκB activation. CS-induced airway CC16 deficiency increases CS-induced pulmonary inflammation and injury and likely contributes to the pathogenesis of COPD.

Clara cell 10-kD protein (CC10) is a potent anti-inflammatory protein that is normally abundant in the respiratory tract. CC10 is deficient and oxidized in premature infants with poor clinical outcome (death or the development of bronchopulmonary dysplasia). The safety, pharmacokinetics, and anti-inflammatory activity of recombinant human CC10 (rhCC10) were evaluated in a randomized, placebo-controlled, doubleblinded, multicenter trial in premature infants with respiratory distress syndrome. A total of 22 infants (mean birth weight: 932 g; gestational age: 26.9 wk) received one intratracheal dose of placebo (n ϭ 7) or 1.5 mg/kg (n ϭ 8) or 5 mg/kg (n ϭ 7) rhCC10 within 4 h of surfactant treatment. Pharmacokinetic analyses demonstrated that the serum halflife was 11.6 (1.5 mg/kg group) and 9.9 h (5 mg/kg group). Excess circulating CC10 was eliminated via the urine within 48 h. rhCC10-treated infants showed significant reductions in total cell count (p Ͻ 0.0002), neutrophil counts (p Ͻ 0.001), and total protein concentrations (p Ͻ 0.01) and tended to have decreased IL-6 (p Ͻ 0.07) in tracheal aspirate fluid collected over the first 3 d of life. Infants in all three groups showed comparable growth. At 36 wk postmenstrual age, five of seven infants were still hospitalized and two of seven infants were receiving oxygen in the placebo group compared with two of seven hospitalized and one of seven receiving oxygen in the 1.5-mg/kg group and four of six hospitalized and three of six receiving oxygen in the 5-mg/kg group. A single intratracheal dose of rhCC10 was well tolerated and had significant anti-inflammatory effects in the lung. Multiple doses of rhCC10 will be investigated for efficacy in reducing pulmonary inflammation and ameliorating bronchopulmonary dysplasia in future studies. Bronchopulmonary dysplasia (BPD) affects 20 -60% of all premature, very low birth weight infants. It is associated with substantial morbidity and mortality as well as extremely high health care costs. Although the widespread use of exogenous surfactant and antenatal steroid therapy has reduced the overall severity of BPD, the prevalence of this condition has increased with improved survival of very low birth weight infants. BPD is a multifactorial disease process that is the end result of an immature, surfactant-deficient lung that has been exposed to hyperoxia, mechanical ventilation, and infection. These forces initiate a cascade of proinflammatory cytokines that lead to the development of significant inflammatory changes and chronic lung injury.Clara cell 10-kD protein (CC10) is also known as uteroglobin. It is a small homodimeric secretory protein that is produced by mucosal epithelial cells (1). In humans, Clara cells are the main site of CC10 production (located in the airways), and several other organs synthesize smaller amounts of mRNA encoding this protein (2-4). CC10 also circulates in the blood

Introduction Club cell protein 16 (CC16) is the most abundant protein in bronchoalveolar lavage fluid. CC16 has anti-inflammatory properties in smoke-exposed lungs, and chronic obstructive pulmonary disease (COPD) is associated with CC16 deficiency. Herein, we explored whether CC16 is a therapeutic target for COPD. Areas Covered We reviewed the literature on the factors that regulate airway CC16 expression, its biologic functions and its protective activities in smoke-exposed lungs using PUBMED searches. We generated hypotheses on the mechanisms by which CC16 limits COPD development, and discuss its potential as a new therapeutic approach for COPD. Expert Opinion CC16 plasma and lung levels are reduced in smokers without airflow obstruction and COPD patients. In COPD patients, airway CC16 expression is inversely correlated with severity of airflow obstruction. CC16 deficiency increases smoke-induced lung pathologies in mice by its effects on epithelial cells, leukocytes, and fibroblasts. Experimental augmentation of CC16 levels using recombinant CC16 in cell culture systems, plasmid and adenoviral-mediated over-expression of CC16 in epithelial cells or smoke-exposed murine airways reduces inflammation and cellular injury. Additional studies are necessary to assess the efficacy of therapies aimed at restoring airway CC16 levels as a new disease-modifying therapy for COPD patients.

Intracellular lipopolysaccharide (LPS) triggers the non-canonical inflammasome pathway, resulting in pyroptosis of innate immune cells. In addition to its well-known proinflammatory role, LPS can directly cause regression of some tumors, although the underlying mechanism has remained unknown. Here we show that secretoglobin(SCGB)3A2, a small protein predominantly secreted in airways, chaperones LPS to the cytosol through the cell surface receptor syndecan-1; this leads to pyroptotic cell death driven by caspase-11. SCGB3A2 and LPS co-treatment significantly induced pyroptosis of macrophage RAW264.7 cells and decreased cancer cell proliferation in vitro, while SCGB3A2 treatment resulted in reduced progression of xenograft tumors in mice. These data suggest a conserved function for SCGB3A2 in the innate immune system and cancer cells. These findings demonstrate a critical role for SCGB3A2 as an LPS delivery vehicle; they reveal one mechanism whereby LPS enters innate immune cells leading to pyroptosis, and they clarify the direct effect of LPS on cancer cells.

Despite the widespread use of exogenous surfactant, acute and chronic lung injury continues to be a major cause of morbidity in preterm infants. CC10 is a protein produced by Clara cells that inhibits phospholipase A 2 and has anti-inflammatory and antifibrotic properties. We studied whether intratracheal (IT) recombinant human Clara cell protein (rhCC10) could safely minimize lung injury in a newborn piglet model of acute lung injury. Twenty-nine newborn piglets were given Survanta and then ventilated for 48 h receiving the following: room air (group 1); 100% O 2 (group 2); or 100% O 2 and 25, 5, or 1 mg/kg (groups 3, 4, and 5, respectively) of IT rhCC10 (diluted to 2 mL/kg with saline) at time 0. Laboratory studies, oxygen ratios, static pressure-volume curves, bronchoalveolar lavage (for inflammatory markers), and histologic analyses were performed over the 48-h study period. Pulmonary compliance and oxygenation were significantly improved in animals receiving 5 mg/kg IT rhCC10 compared with room air and 100% O 2 controls (p Ͻ 0.004 and p Ͻ 0.05, respectively, ANOVA). Reductions in inflammatory markers were seen in animals receiving rhCC10, although changes did not reach statistical significance. No significant toxicity was noted. rhCC10 appeared safe and improved pulmonary function in this newborn piglet model of hyperoxic lung injury. We speculate that rhCC10 may represent a promising therapy for the prevention of lung injury in preterm infants. Bronchopulmonary dysplasia continues to be a significant problem for the preterm infant despite improvements in neonatal intensive care. Although the use of antenatal steroids and exogenous surfactant has resulted in decreased severity of BPD, the prevalence of BPD in the preterm population has actually increased. BPD is a multifactorial disease process that is the end result of an immature, surfactant-deficient lung that has been exposed to hyperoxia, mechanical volutrauma, and infection. These forces initiate a cascade of pro-inflammatory cytokines that lead to the development of significant inflammatory changes and chronic lung injury.CC10 is produced by the nonciliated cells of the tracheobronchial epithelial tree and is thought to have numerous anti-inflammatory properties. It has been shown to play a significant role, both in vitro and in vivo, in modulating inflammation (1-5). CC10, also known as uteroglobin, inhibits sPLA 2 (2, 6), an enzyme that degrades surfactant and facilitates prostaglandin biosynthesis (through the cleavage of arachidonic acid from cell membrane phospholipids). In vitro, CC10 has been shown to inhibit neutrophil and phagocyte chemotaxis (3) and IL-stimulated release of numerous cytokines in human blood lymphocytes (tumor necrosis factor-␣, IL-1␤, and interferon-␥) (4). CC10 also inhibits the formation of the proinflammatory fibronectin/IgA complex that may mitigate fibrotic changes in the lung (7). Further in vivo evidence of these ABSTRACT509