Novel Neutrophil-Derived Proteins in Bronchoalveolar Lavage Fluid Indicate an Exaggerated Inflammatory Response in Pediatric Cystic Fibrosis Patients

Abstract

Background: Airway inflammation in cystic fibrosis (CF) is exaggerated and characterized by neutrophil-mediated tissue destruction, but its genesis and mechanisms remain poorly understood. To further define the pulmonary inflammatory response, we conducted a proteome-based screen of bronchoalveolar lavage fluid (BALF) collected from young children with and without CF experiencing endobronchial infection. Methods: We collected BALF samples from 45 children younger than 5 years and grouped them according to the presence of respiratory pathogens: ≥1 × 105 colony-forming units (CFU)/mL BALF (18 and 12 samples with and without CF, respectively) and <1 × 105 CFU/mL (23 and 15 samples). BALF proteins were analyzed with SELDI-TOF mass spectrometry (MS) and H4 ProteinChips®. Proteins were identified and characterized using trypsin digestion, tandem MS, Fourier transform ion cyclotron resonance MS, immunoblotting, and ELISA. Results: The SELDI-TOF MS BALF profiles contained 53 unique, reliably detected proteins. Peak intensities of 24 proteins differed significantly between the CF and non-CF samples. They included the neutrophil proteins, α-defensin 1 and 2, S100A8, S100A9, and S100A12, as well as novel forms of S100A8 and S100A12 with equivalent C-terminal deletions. Peak intensities of these neutrophil proteins and immunoreactive concentrations of selected examples were significantly higher in CF than non-CF samples. Conclusions: Small neutrophil-derived BALF proteins, including novel C-terminal truncated forms of S100A proteins, are easily detected with SELDI-TOF MS. Concentrations of these molecules are abnormally high in early CF lung disease. The data provide new insights into CF lung disease and identify novel proteins strongly associated with CF airway inflammation.

Monomeric Calgranulins Measured by SELDI-TOF Mass Spectrometry and Calprotectin Measured by ELISA as Biomarkers in Arthritis

“…We confirmed the identity of this peak in the present study, not only in serum samples from RA patients but also in samples from patients with other inflammatory diseases. The mass of the protein for the peak identified as S100A9* was in good agreement with that of a truncated form of S100A9, a variant that has already been detected by ultraviolet MALDI MS in human buffy coats (31 ), in head and neck squamous cell carcinoma (33 ), and in neutrophils from pediatric cystic fibrosis patients (34 ). The SAA variants had previously been identified in renal cancer, but not in arthritis or in patients with IBD.…”

“…The identification of the various SAA forms may be important because they may have different pathophysiological roles. The recent identification via SELDI-TOF analysis of several truncated forms of S100A8 and S100A12 in cystic fibrosis patients suggests that C-terminal truncations affect protein function (34 ). The presence of S100A8 and S100A12, but not calprotectin, have been found to be characteristic of intra-amniotic inflammation (22 ), and SAA variants with different properties, such as differential susceptibility to matrix metalloproteinase digestion, have been described (38 ).…”

Identification of disease- and therapy-associated proteome changes in the sera of patients with myelodysplastic syndromes and del(5q)

“…There is evidence suggesting that it could be a powerful tool for characterizing the proteome of different tissues and identifying potential biomarkers for various diseases, including cancer. [15][16][17][18] At the same time, great concerns have also been raised regarding its reproducibility and other instrumental and technical limitations. 19,20 In the present study, we sought to determine whether serum protein expression profiling with surface-enhanced laser desorption/ionization time-of-flight mass spectrometry platform could be used to search for potential disease-and therapy-associated markers for MDS.…”

Association of high levels of α-defensins and S100A proteins with Candida mannan detection in bronchoalveolar lavage fluid of preterm neonates

“…Among detected proteins that are receiving further attention, especially for their function and involvement in acute and chronic inflammatory conditions, are the α-defensins and S100A member proteins (calgranulins) (13,14). To date, six α-defensins have been characterized: the human neutrophil peptides 1-4, mainly produced by neutrophils, and the human defensins 5-6 expressed by the Paneth cells (15)(16)(17)(18).…”

“…McMorran et al (13) conducted a proteome-based analysis of BALFs from young children suffering from cystic fibrosis with and without lung infection. They detected abnormally high concentrations of α-defensin 1 and 2, S100A8, S100A9, and S100A12, as well as novel forms of S100A8 and S100A12, in BALFs of early cystic fibrosis lung disease.…”