Clara cell 16 protein in COPD sputum: a marker of small airways damage?
ABSTRACT The development of chronic obstructive pulmonary disease (COPD) in smokers and their susceptibility to infections is not fully understood. Recent evidences suggest that Clara cells play a part in host defense, immunomodulatory response and airways remodelling through the production of specific factors such as Clara cell 16 (CC-16). This protein has never been related to patients' lung function tests, blood gases parameters and diseases severity.
To evaluate a possible correlation between CC-16 expression in sputum, measured by a new methodological approach, and the degree of severity in patients with moderate and severe COPD. We also analyzed possible correlations between CC-16 and cytological sputum population, arterial blood gases and lung function.
We analyzed 20 patients, mean age 72.95, classified on the basis of the global initiative for chronic obstructive lung disease guidelines (GOLD 2006). The samples were processed for cytological analysis and CC-16 levels were assessed by Western blot. We found lower levels of CC-16 in severe COPD compared to moderate ones (p<0.027). No statistically significant differences were found between CC-16 expression and sputum cellularity (except for macrophages), arterial blood gases, and spirometric parameters. Multiple linear regression analysis of CC-16 versus functional and cytological parameters showed no significance.
We found a significantly different expression of CC-16 in COPD patients, according to their stage of severity, as defined by the GOLD 2006 guidelines. Considering CC-16 properties in innate immunity, a possible link between protein expression, innate immune system, and COPD infectious exacerbations may be hypothesized but further investigation are needed.
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ABSTRACT: Clara cell 10-kDa protein (CC10)/ uteroglobin (UG) is a nonglycoprotein with a molecular mass of 16 kilodaltons, which is produced by mucosal epithelial cells in the lung (Clara cells), uterus and prostate. Like other low molecular weigh proteins it is catabolized in renal proximal tubules. Structurally it is a homodimer of subunits of 70 amino acids covalently bound in an antiparallel manner. It belongs to secretogobin (SCGB) family and is assigned as subgroup 1A1. The function of the protein so far elucidated is immunoregulatory and anti-inflammatory in innate immunity. The knockout mouse of UG gene resulted in aggravation of inflammation by allergic and hyperoxic stimuli. It also showed very similar pathological features with human IgA nephropathy. The value is changed in the lung fluid and serum of various inflammatory and allergic lung diseases. Several kinds of single nucleotide polymorphisms (SNPs) in human CC10/UG gene were recently discovered; Adenine allele accumulation in G38A SNP has possible association with asthma and IgA nephropathy, being paralleled with disease severity of IgA nephropathy. Its expression is enhanced by some transcriptional factors induced by cytokines such as interferon-gamma. For cancer cells, the protein functions as an antagonist of neoplastic phenotype. CC10/UG forms one of intra- and intercellular regulators involved in inflammation and malignant transformation in the respiratory and urogenital fields.Current Pharmaceutical Design 02/2003; 9(14):1139-49. · 3.31 Impact Factor
- Journal of Clinical Investigation 08/1990; 86(1):1-6. · 12.81 Impact Factor
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ABSTRACT: Clara cell secretory protein (CC16, CC10, or CCSP), the major secretory protein of the Clara cell, presents several biologic properties, suggesting that it may play a protective role against intrapulmonary inflammatory processes. The aim of the present study was to investigate the changes of CC16 concentrations in the lung, bronchoalveolar lavage fluid (BALF), and serum of rats with acute lung injury induced by lipopolysaccharide (LPS). These changes were compared with Clara cell density, CC16 mRNA level in the lung and classic indices of inflammation in BALF. Injected at doses of 10, 100, or 200 microgram/100 g body weight, LPS induced an acute lung inflammation as estimated by an increased influx of cells and albumin in the BALF. This inflammatory response was associated with a marked reduction of CC16 concentrations in BALF and lung homogenate as well as of the CC16 mRNA levels in the lung. At the highest dose of LPS, the CC16-positive cell density in the bronchiolar epithelium was also decreased. In serum, by contrast, the concentration of CC16 was elevated as a consequence of increased airway permeability. Pretreating rats intraperitoneally with dexamethasone (2 mg/kg) significantly lowered the leukocyte influx and attenuated the albumin increase in BALF. Dexamethasone, however, failed to prevent the increased airway permeability to CC16, suggesting that during inflammation different mechanisms regulate the leakage of proteins across the alveolocapillary barrier depending on the direction of passage and/or the size of the protein. Our results show a marked decrease of the secretion and synthesis of CC16 during LPS-induced acute lung inflammation.American Journal of Respiratory and Critical Care Medicine 06/2000; 161(5):1624-30. · 11.04 Impact Factor