Clara cell 16 KDa protein mitigates house dust mite-induced airway inflammation and damage via regulating airway epithelial cell apoptosis in a manner dependent on HMGB1-mediated signaling inhibition.

BACKGROUND: House dust mite (HDM) inhalation can cause airway epithelial damage which is implicated in the process of airway inflammation in asthma. High mobility group box 1 (HMGB1) is critically required for cellular damage and apoptosis as an important endogenous danger signal. Recently, Clara cell 16KDa protein (CC16) has been identified to exert anti-inflammatory and immunomodulatory influence in various injury-related diseases model. However, little is known about its ability to protect against airway epithelial injury in allergic asthma. This study was aimed to clarify the protective roles of CC16 on airway epithelia in HDM-induced asthma and the regulation of HMGB1 by CC16. METHODS: Mice were sensitized and challenged by HDM extract and administrated intranasally with CC16 (5 µg/g or 10 µg/g) or saline in the challenged period. The BEAS-2B human airway epithelial cell line were cultured with CC16 or the control vehicle and then exposed to HDM. Knockdown or overexpression of HMGB1 was induced by cell transfection or intratracheal injection of recombinant adenovirus. RESULTS: CC16 treatment decreased airway inflammation and histological damage of airway epithelium dose-dependently in HDM-induced asthma model. Airway epithelia apoptosis upon HDM stimulation was noticeably abrogated by CC16 in vivo and in vitro. In addition, upregulation of HMGB1 expression and its related signaling were also detected under HDM conditions, while silencing HMGB1 significantly inhibited the apoptosis of BEAS-2B cells. Furthermore, the activity of HMGB1-mediated signaling was restrained after CC16 treatment whereas HMGB1 overexpression abolished the protective effect of CC16 on HDM-induced airway epithelia apoptosis. CONCLUSIONS: Our data confirm that CC16 attenuates HDM-mediated airway inflammation and damage via suppressing airway epithelial cell apoptosis in a HMGB1-dependent manner, suggesting the role of CC16 as a potential protective option for HDM-induced asthma.

Recombinant CC16 protein inhibits the production of pro-inflammatory cytokines via NF-κB and p38 MAPK pathways in LPS-activated RAW264.7 macrophages.

Accumulating evidence indicates that Clara cell protein-16 (CC16) has anti-inflammatory functions, although the involved molecular pathways have not been completely elucidated. Here, we evaluated the effect of recombinant rat CC16 (rCC16) on the expression of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8 in lipopolysaccharide (LPS)-stimulated mouse macrophages (RAW264.7 cells) and explored the underlying molecular mechanisms. It was found that rCC16 inhibited LPS-induced TNF-α, IL-6, and IL-8 expression at both the messenger ribonucleicacid (mRNA) level and protein level in a concentration-dependent manner, as demonstrated by real-time reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Such suppressive effects were accompanied by the inhibition of transcriptional activity and the deoxyribonucleic acid binding activity of nuclear factor (NF)-κB but not activator protein (AP)-1. Western blot analysis further revealed that rCC16 inhibited the increase of nuclear NF-κB and the reduction of cytosolic NF-κB, the phosphorylation and reduction of NF-κB inhibitory protein IκBα, and the p38 mitogen-activated protein kinase (MAPK)-dependent NF-κB activation by phosphorylation at Ser276 of its p65 subunit. Furthermore, rCC16 was found to have no effect on the phosphorylation of c-Jun N-terminal kinase, c-Jun, or the nuclear translocation of c-Jun. In addition, reduction of TNF-α, IL-6, and IL-8 were reversed when the level of endogenous uteroglobin-binding protein was reduced by RNA interference in rCC16- and LPS-treated RAW264.7 cells. Our data suggest that rCC16 suppresses LPS-mediated inflammatory mediator TNF-α, IL-6, and IL-8 production by inactivating NF-κB and p38 MAPK but not AP-1 in RAW264.7 cells.

Label-free LC-MS/MS shotgun proteomics to investigate the anti-inflammatory effect of rCC16.

Clara cell protein (CC16) is an anti-inflammatory protein, which is expressed in the airway epithelium. It is involved in the development of airway inflammatory diseases, including chronic obstructive pulmonary disease and asthma. However, the exact molecular mechanism underlying its anti­inflammatory action remains to be fully elucidated. The aim of the present study was to define the protein profiles of the anti­inflammatory effect of CC16 in lipopolysaccharide (LPS)­treated rat tracheal epithelial (RTE) cells using shotgun proteomics. Protein extracts were obtained from control RTE cells, RTE cells treated with LPS and RTE cells treated with LPS and recombinant CC16 (rCC16). Subsequent label­free quantification and bioinformatics analyses identified 12 proteins that were differentially expressed in the three treatment groups as a cluster of five distinct groups according to their molecular functions. Five of the twelve proteins were revealed to be associated with the cytoskeleton: Matrix metalloproteinase­9, myosin heavy chain 10, actin­related protein­3 homolog, elongation factor 1­α­1 (EF­1­α­1), and acidic ribosomal phosphoprotein P0. Five of the twelve proteins were associated with cellular proliferation: DNA­dependent protein kinase catalytic subunit, EF­1­α­1, tyrosine 3­monooxygenase, caspase recruitment domain (CARD) protein 12 and adenosylhomocysteinase (SAHH) 3. Three proteins were associated with gene regulation: EF­1­α­1, SAHH 3 and acidic ribosomal phosphoprotein P0. Three proteins were associated with inflammation: Tyrosine 3­monooxygenase, CARD protein 12 and statin­related protein. ATPase (H+­transporting, V1 subunit A, isoform 1) was revealed to be associated with energy metabolism, and uridine diphosphate glycosyltransferase 1 family polypeptide A8 with drug metabolism and detoxification. The identified proteins were further validated using reverse transcription­quantitative polymerase chain reaction. These protein profiles, and their interacting protein network, may facilitate the elucidation of the molecular mechanisms underlying the anti­inflammatory effects of CC16.

Club Cell Protein 16 (CC16) Augmentation: A Potential Disease-modifying Approach for Chronic Obstructive Pulmonary Disease (COPD).

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.

Intratracheal Clara cell secretory protein (CCSP) administration in preterm infants with or at risk of respiratory distress syndrome.

BACKGROUND: Clara cell secretary protein (CCSP) is an immune-modulating and anti-inflammatory agent. CCSP is available synthetically as recombinant human Clara cell protein (rhCC10). It has been shown in animal models to reduce lung injury, improve pulmonary compliance and oxygenation, decrease systemic inflammation and up-regulate surfactant protein and vascular endothelial growth factor expression. These properties makes intratracheally administered CCSP a potential agent in prevention of chronic lung disease (CLD). OBJECTIVES: To determine the effect of intratracheal CCSP administration compared to placebo or no treatment on morbidity and mortality in preterm infants with or at risk of respiratory distress syndrome (RDS). SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library, October 2010), MEDLINE and PREMEDLINE (1950 to October 2010), EMBASE (1980 to October 2010) and CINAHL (1982 to October 2010). We searched proceedings of scientific meetings, Google Scholar and reference lists of identified studies, and contacted expert informants and surfactant manufacturers. SELECTION CRITERIA: Published, unpublished and ongoing randomised controlled, cluster-randomised or quasi-randomised trials of intratracheal CCSP administration, compared to placebo or no treatment on morbidity and mortality in preterm infants at risk of RDS. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for eligibility and quality, and extracted data. MAIN RESULTS: One pilot study was identified and included. This study enrolled 22 preterm infants 700 to 1300g with established RDS who required ventilation for surfactant administration. Infants received one intratracheal dose of placebo (n = 7), 1.5 mg/kg (n = 8) or 5 mg/kg (n = 7) rhCC10 within four hours of surfactant treatment. At either dose of rhCC10, no significant difference was reported in CLD (36 weeks postmenstrual age or 28 days), mortality, intraventricular haemorrhage, periventricular leukomalacia, patent ductus arteriosus, necrotising enterocolitis, sepsis or days supplemental oxygen compared to placebo. A significant increase in days mechanical ventilation was reported for infants receiving rhCC10 5mg/kg (mean difference 12.00, 95% confidence interval 0.39 to 23.61) but not at the lower dose. The study reported that a single intratracheal dose of rhCC10 was well tolerated and resulted in a significant reduction in tracheal aspirate neutrophil and total cell count, and lung protein concentration. There was no significant difference reported in tracheal aspirate cytokine levels between groups. AUTHORS' CONCLUSIONS: There are insufficient data to determine the role of rhCC10 in clinical practice. Further studies are required to determine if rhCC10 reduces lung inflammation in infants at risk of CLD, and to determine dose and dosing strategy.

The expression of osteopontin and its association with Clara cell 10 kDa protein in allergic rhinitis.

BACKGROUND: Osteopontin (OPN) is a multifunctional protein that has recently been linked to allergic diseases. Clara cell 10 kDa protein (CC10) is another protein linked to allergy, and has been suggested to have an inhibitory role in inflammatory airway diseases. At this time, it is not known whether OPN is involved in allergic rhinitis (AR) or if there is any association between CC10 and OPN in AR. OBJECTIVE: To study the expression of OPN and its potential association with CC10 in AR. METHODS: The expression of CC10 and OPN in nasal mucosa of AR patients was investigated. AR animal models were established by using wild-type and CC10-knockout mice. In some experiments, human recombinant CC10 protein was given to AR mice during either sensitization or challenge. The phenotypic changes were examined by histology and real-time RT-PCR. The direct effect of CC10 on the OPN expression in spleen mononuclear cells and on the OPN-induced inflammatory cytokine expression in BEAS-2B cells was measured through in vitro cell culture. RESULTS: OPN expression was up-regulated, with a concomitant down-regulation of CC10, in AR patients, showing a significant negative correlation between their expression. Compared with control mice sensitized with PBS, the OPN expression was significantly increased in AR mice; such an increase was more prominent in CC10-knockout mice, compared with wild-type. Administration of CC10 during both sensitization and challenge could markedly ameliorate Th2-skewed inflammation and OPN expression in nasal mucosa. CC10 administration at the sensitization phase could also reduce spleen OPN expression. The in vitro study showed that CC10 directly down-regulated the OPN expression in spleen mononuclear cells stimulated with OVA and suppressed the OPN-induced expression of Th2 cytokines and pro-inflammatory cytokines in BEAS-2B cells. CONCLUSION: In the context of allergic airway responses, CC10 can inhibit OPN expression and suppress the Th2-promoting function of OPN, resulting in CC10's inhibitory biological effects.

Effects of Clara cell 10 (CC10) protein on symptoms and signs of allergic rhinitis.

BACKGROUND: The Clara cell 10 (CC10) protein is produced by the airway epithelium. Reduced levels of CC10 are associated with allergic rhinitis and asthma. In experimental models, treatment with the CC10 protein may reduce features of airway inflammation. OBJECTIVES: To examine whether or not topical treatment with recombinant human CC10 (rhCC10) affects symptoms and signs of allergic rhinitis in a pollen season model. METHODS: Out of the pollen season, patients with allergic rhinitis received treatment with rhCC10, 0.56 mg per nasal cavity, once daily for 7 days in a double-blinded, placebo-controlled, crossover design. During this period, individualized allergen challenges were given once daily. Symptoms and peak nasal inspiratory flow (PNIF) were recorded daily in the morning, 10 minutes after challenge, and in the evening. Mean recordings of the last 3 days of the challenge series were used in the analysis. Nasal lavages were performed at the end of each challenge period, and eosinophil cationic protein, myeloperoxidase, and alpha2-macroglobulin levels were measured as indices of eosinophil and neutrophil activity and plasma exudation, respectively. RESULTS: Recombinant human CC10 did not affect allergen-induced morning, postchallenge, or evening symptoms compared with placebo. Morning, postchallenge, and evening PNIF were not improved by rhCC10. No statistically significant differences were observed between rhCC10 and placebo for any of the lavage fluid indices. CONCLUSIONS: Repeated nasal administrations of rhCC10 protein, in the present dose, do not exert antiallergic effects in seasonal allergic rhinitis.

CC10 reduces inflammation in meconium aspiration syndrome in newborn piglets.

Complications from meconium aspiration syndrome (MAS) remain significant despite a variety of therapeutic interventions. Clara cell protein (CC10) is a novel anti-inflammatory agent that can also inhibit phospholipase A2 (PLA2) (an important component of meconium). The present study examined whether administration of recombinant human CC10 (rhCC10) would reduce inflammation and improve lung function in a piglet model of MAS. Following meconium instillation, piglets exhibited significant physiologic dysfunction that improved significantly after surfactant administration. Analysis of tracheal aspirates revealed significant increases in both tumor necrosis factor (TNF) alpha and interleukin (IL)-8 after meconium instillation. rhCC10-treated animals had significantly lower TNF-alpha levels at 24 h (561 +/- 321 versus 1357 +/- 675 pg/mL, p < 0.05) compared with saline controls. There were no differences between rhCC10-treated and untreated groups with respect to other measured physiologic variables or inflammatory markers, including secretory PLA2 activity. Histologic analyses revealed marked inflammatory infiltrates and thickened alveolar walls, but no significant differences among rhCC10 and control animals. Newborn piglets with MAS have significant physiologic dysfunction, marked inflammatory changes and histologic abnormalities, which was partially counteracted by a single dose of exogenous surfactant and rhCC10.

Effects of recombinant Clara cell secretory protein (rhCC10) on inflammatory-related matrix metalloproteinase activity in a preterm lamb model of neonatal respiratory distress.

OBJECTIVE: To test the hypothesis that recombinant Clara cell secretory protein (rhCC10) instillation would foster improved lung function, acute structural preservation, and attenuation of matrix metalloproteinase (MMP) activity in a surfactant-deficient, mechanically ventilated lung. DESIGN: Interventional laboratory study. SETTING: An academic medical research facility in the northeastern United States. SUBJECTS: Sedated, ventilated premature lambs. INTERVENTIONS: Preterm lambs (n = 18; 126 +/- 3 days gestation) were instrumented, ventilated, and treated with 100 mg/kg exogenous surfactant. Lambs were randomized to receive 0, 0.5, or 5.0 mg/kg rhCC10 (n = 6 per group) and were ventilated for 4 hrs. MEASUREMENTS AND MAIN RESULTS: Posttreatment, lung function and cardiopulmonary stability were monitored for the ventilation period and then animals were killed for in vitro surfactant function analysis, lung histomorphometry, and analysis of MMP-2, -7, and -9 as well as their tissue inhibitors (TIMP)-1 and -2. Ventilation efficiency and pulmonary compliance were improved in the 5.0-mg/kg rhCC10 group by 4 hrs. Lung expansion was variable in the apical regions only. MMP-2 quantity was greater in the apical than the base lung regions of rhCC10-treated groups, and rhCC10 decreased MMP-7 in the base of the lung. CONCLUSIONS: These data suggest that improved lung function in the surfactant-treated preterm lamb following intratracheal rhCC10 may be related to the reduction of proteolytic activity of MMP-7.

Effects of an intratracheally delivered anti-inflammatory protein (rhCC10) on physiological and lung structural indices in a juvenile model of acute lung injury.

BACKGROUND: Mechanical ventilation results in acute lung trauma that can stimulate processes that alter lung development. Activation of matrix metalloproteinases (MMPs) and their tissue-produced inhibitors (TIMPs) is initiated by the inflammatory response to mechanical ventilation and are involved in breakdown of the basement membrane and parenchymal modeling. OBJECTIVES: The aim of this study was to test the hypothesis that rhCC10, a lung anti-inflammatory mediator, would foster improved lung function, structural preservation, and a reduction in net MMP activity in a juvenile model of acute lung injury. METHODS: Twenty-four juvenile rabbits were saline-lavage-injured and treated with 100 or 25 mg/kg surfactant (Survanta, Ross Labs) with or without rhCC10 (Claragen, Inc.; n=6 per group). Animals were ventilated for 4 h, then euthanized for in vitro surfactant function analysis, lung histomorphometry, and analysis of MMP-2, MMP-7, and MMP-9 and TIMPs 1 and 2 in the lung. RESULTS: Apical lung expansion, reduced with the lower dose of surfactant, was partially restored with the addition of rhCC10. Alveolar septal wall thickness was reduced (p<0.05) with low-dose surfactant plus rhCC10 compared to high-dose surfactant alone. Increased within-group variance in MMP-2 and MMP-9 proteolytic activity was found with the low-dose surfactant and was abolished with rhCC10. MMP-7 was reduced (p<0.05) with rhCC10 administration, independent of surfactant dose. CONCLUSIONS: Intratracheal administration of the anti-inflammatory rhCC10 resulted in preserved lung structure and MMP/TIMP profile after 4 h of mechanical ventilation, in a surfactant dose-dependent manner.

Recombinant human Clara cell secretory protein in acute lung injury of the rabbit: effect of route of administration.

OBJECTIVE: To test the hypothesis that intratracheal instillation of Clara cell secretory protein (CC 10) to the lung may afford greater protection than intravenous administration from ventilator-induced lung inflammation. DESIGN: Interventional laboratory study. SETTING: An academic medical research facility in northeastern United States. SUBJECTS: Sedated, lavage-injured juvenile rabbits. INTERVENTIONS: A total of 18 juvenile rabbits were anesthetized, ventilated, injured with saline lavage (Pao2 of <100 mm Hg; respiratory compliance of <0.50 mL.cm H2O.kg and <50% baseline), and randomized to receive intratracheally administered surfactant plus no recombinant human CC 10 (rhCC 10, control), intravenous rhCC 10, or intratracheal rhCC 10. MEASUREMENT AND MAIN RESULTS: Arterial blood chemistry and pulmonary mechanics were monitored; plasma and urine were collected serially. After 4 hrs of ventilation, lungs were lavaged and harvested. Surfactant function was analyzed from bronchoalveolar lavage samples (surfactometry); rhCC 10, interleukin-8, and lung myeloperoxidase concentrations were measured. Pao2, oxygenation index, ventilatory efficiency index, and respiratory compliance were not different across time or group beyond injury. Surfactometry data identified no differences as a function of group or time. Plasma, bronchoalveolar lavage, and lung interleukin-8 concentrations, lung myeloperoxidase concentrations, and inflammatory cell counts in the alveolar and interstitial spaces of intravenous and intratracheal groups were lower than in the control group (p < .05) but not statistically different from each other. Concentrations of rhCC 10 in lung, bronchoalveolar lavage, and plasma were greater in the intratracheal group than in the intravenous group (p<.05). Urine rhCC 10 concentrations were greater for the intravenous group than for the intratracheal group (p<.05) at 1, 3, and 4 hrs after treatment. No group differences in histomorphometry were noted. CONCLUSIONS: Both intravenous and intratracheal rhCC 10 delivery, after surfactant therapy, effectively decrease lung inflammation vs. surfactant alone. While supporting the physiologic profile, intratracheal instillation results in greater, maintained lung and plasma rhCC 10 pools compared with intravenous administration. As such, intratracheal instillation of rhCC 10 may afford more prolonged protection against lung inflammation than intravenous administration.

Dose response to rhCC10-augmented surfactant therapy in a lamb model of infant respiratory distress syndrome: physiological, inflammatory, and kinetic profiles.

While surfactant (SF) therapy alone improves respiratory distress syndrome (RDS)-associated gas exchange and lung stability, absence of anti-inflammatory proteins limits efficacy with respect to inflammation. Clara cell secretory protein (CC10), deficient in preterm infants, prevents SF degradation and has anti-inflammatory properties. In this study, intratracheal recombinant human (rh) CC10 (Claragen)-augmented SF (Survanta, Ross) therapy was examined in a premature lamb model of RDS with respect to inflammation and kinetic dose-response profiles. Preterm lambs (n = 24; gestational age: 126 +/- 3 days) were delivered via cesarean section, sedated, ventilated, and randomized into groups: 100 mg/kg SF, 100 mg/kg SF followed by 0.5 mg/kg rhCC10, 100 mg/kg SF followed by 1.5 mg/kg rhCC10, and 100 mg/kg SF followed by 5.0 mg/kg rhCC10. Arterial blood chemistry and lung mechanics were monitored; lungs were lavaged and snap-frozen after 4 h. TNF-alpha, IL-8 in plasma; TNF-alpha, IL-6, IL-8, myeloperoxidase in lung; and rhCC10 in plasma, urine, bronchoalveolar lavage, and lung were analyzed. Improvement in compliance, peak inspiratory pressure, and ventilatory efficiency index were greatest (P < 0.05) with SF + 5.0 mg/kg rhCC10. Plasma, urine, bronchoalveolar lavage, and lung [rhCC10] (where brackets denote concentration) increased (P < 0.01) with dose. Plasma [IL-8] was lower (P < 0.05) with rhCC10 than SF alone. Treatment with at least 1.5 mg/kg rhCC10 resulted in lower (P < 0.05) lung [TNF-alpha], [IL-8], and [myeloperoxidase]; SF + 1.5 mg/kg rhCC10 group had lower (P < 0.05) lung [IL-6], compared with all other groups. Compared with SF alone, SF augmented with at least 1.5 mg/kg rhCC10 decreased RDS-induced lung and systemic inflammation. Given that inflammation may lead to functional compromise, these data suggest that early intervention with rhCC10 may enhance SF therapy and warrant longer duration studies to determine its role to decrease long-term complications of ventilator management.

Antiflammin 1 peptide delivered non-invasively by iontophoresis reduces irritant-induced inflammation in vivo.

The potential of an anti-inflammatory peptide (antiflammin 1) to reduce irritation when delivered transdermally by iontophoresis was examined. A model drug irritant, chlorpromazine, was co-delivered with and without antiflammin 1 by iontophoresis to hairless guinea pigs transdermally. Quantitative skin irritation measurements were obtained by monitoring erythema by skin color reflectance with the Minolta Chromameter. Antiflammin 1 delivered by iontophoresis significantly decreased, but did not eliminate, the erythema associated with co-delivery of an irritating drug compound. Lesion formation was also reduced in the presence of antiflammin 1. In vitro flux across hairless guinea pig skin demonstrated no significant differences in flux of the irritant compound in the presence or absence of antiflammin 1. In vivo generation and efflux of the inflammation mediator Prostaglandin E2 increased during 24-h application of irritant and was unchanged in the presence of antiflammin 1. This result is discussed with respect to recent evidence that antiflammins may act on the lipo-oxygenase pathway. In summary, antiflammin 1, an anti-inflammatory peptide, can be delivered transdermally by iontophoresis with retention of its biological activity in vivo.

Effect of nonapeptide fragments of uteroglobin and lipocortin I on oedema and mast cell degranulation.

The anti-inflammatory action of nonapeptide fragments of uteroglobin or lipocortin I known as antiflammins, was tested in the carrageenan or phospholipase A2 rat paw oedema model. The development of carrageenan-induced oedema in rats was significantly inhibited during the early and late phases of the oedema by the local administration of antiflammins 1 and 2. However, the peptides were not able to inhibit phospholipase A2-induced oedema. The time course of the anti-oedematous activity of nonapeptides after intradermal carrageenan injection may be attributed to their effect on mast cell degranulation and accumulation and activation of leukocytes. Naja naja phospholipase A2 exhibited strong histamine release-inducing activity, which may have contributed to the rat paw oedema induction. Surprisingly, antiflammins had a limited but significant inhibitory effect on histamine secretion.