Project description:Cystic fibrosis (CF) is a life-shortening disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Although bacterial lung infection and the resulting inflammation cause most of the morbidity and mortality, how loss of CFTR first disrupts airway host defense has remained uncertain. We asked what abnormality impairs elimination when a bacterium lands on the pristine surface of a newborn CF airway? To investigate this defect, we interrogated the viability of individual bacteria immobilized on solid grids and placed on the airway surface. As a model we studied CF pigs, which spontaneously develop hallmark features of CF lung disease. At birth, their lungs lack infection and inflammation, but have a reduced ability to eradicate bacteria. Here we show that in newborn wild-type pigs, the thin layer of airway surface liquid (ASL) rapidly killed bacteria in vivo, when removed from the lung, and in primary epithelial cultures. Lack of CFTR reduced bacterial killing. We found that ASL pH was more acidic in CF, and reducing pH inhibited the antimicrobial activity of ASL. Reducing ASL pH diminished bacterial killing in wild-type pigs, and increasing ASL pH rescued killing in CF pigs. These results directly link the initial host defense defect to loss of CFTR, an anion channel that facilitates HCO3- transport. Without CFTR, airway epithelial HCO3- secretion is defective, ASL pH falls and inhibits antimicrobial function, and thereby impairs killing of bacteria that enter the newborn lung. These findings suggest that increasing ASL pH might prevent the initial infection in patients with CF and that assaying ASL pH or bacterial killing could report on the benefit of therapeutic interventions. 11 samples of trachea primary airway epithelial cultures representing CFTR+/+ and CFTR-/- pigs. Pig samples representing 14 bronchus and 12 trachea tissue samples submitted in GSE21071.
Project description:Cystic fibrosis (CF) is a life-shortening disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Although bacterial lung infection and the resulting inflammation cause most of the morbidity and mortality, how loss of CFTR first disrupts airway host defense has remained uncertain. We asked what abnormality impairs elimination when a bacterium lands on the pristine surface of a newborn CF airway? To investigate this defect, we interrogated the viability of individual bacteria immobilized on solid grids and placed on the airway surface. As a model we studied CF pigs, which spontaneously develop hallmark features of CF lung disease. At birth, their lungs lack infection and inflammation, but have a reduced ability to eradicate bacteria. Here we show that in newborn wild-type pigs, the thin layer of airway surface liquid (ASL) rapidly killed bacteria in vivo, when removed from the lung, and in primary epithelial cultures. Lack of CFTR reduced bacterial killing. We found that ASL pH was more acidic in CF, and reducing pH inhibited the antimicrobial activity of ASL. Reducing ASL pH diminished bacterial killing in wild-type pigs, and increasing ASL pH rescued killing in CF pigs. These results directly link the initial host defense defect to loss of CFTR, an anion channel that facilitates HCO3- transport. Without CFTR, airway epithelial HCO3- secretion is defective, ASL pH falls and inhibits antimicrobial function, and thereby impairs killing of bacteria that enter the newborn lung. These findings suggest that increasing ASL pH might prevent the initial infection in patients with CF and that assaying ASL pH or bacterial killing could report on the benefit of therapeutic interventions.
Project description:Idiopathic Pulmonary Fibrosis (IPF) is a pathological condition of unknown etiology which results from injury to the lung and an ensuing fibrotic response that leads to thickening of the alveolar walls and obliteration of the alveolar space. The pathogenesis is not clear and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to Cystic Fibrosis (CF) lung disease. The ATP12A gene encodes the alpha-subunit of the non-gastric H+, K+-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in cystic fibrosis patients. We hypothesize that the ATP12A protein may play a role in the pathogenesis of IPF. Our studies demonstrate that ATP12A protein is overexpressed in distal small airways from IPF patient lungs compared to normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened the bleomycin (BLEO)-induced experimental pulmonary fibrosis. This was prevented by a potassium-competitive proton pump blocker, vonoprazan (VON). This data supports the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has the potential as a novel therapeutic strategy in IPF.
Project description:Our laboratory has held a long interest in the glycosylation changes seen on the surface of airway epithelia of patients with the disease cystic fibrosis (CF). Experiments from our laboratory have detailed a CF glycosylation phenotype of increased Fuca1,3/4 and decreased Fuca1,2 and sialic acid on the surfaces of immortalized and primary CF cells compared to non-CF cells. Further, we have shown that gene transfer and subsequent expression of a wild type CF plasmid in CF airway cells results in correction or reversal of this glycosylation phenotype. We hypothesize that the changes in glycosylation seen in CF cells are key in the pathophysiology of the cystic fibrosis airway disease. For example, it has been shown that Pseudomonas aeruginosa, a bacterium that has a predilection for colonizing CF airways, adheres to asialylated glycolipids and glycoconjugates with terminal Fuca1,3/4. One focus of our laboratory is to elucidate the etiology of the glycosylation changes seen in CF cells and the mechanism by which these changes are reversed by wild type CFTR gene transfer. We propose to study the gene expression of immortalized and primary CF and non-CF airway epithelial cells: 1. CF/T43 vs. BEAS-2B cells. These are two widely used immortalized airway cell lines that we have used extensively in the past. 2. C38 cells; C38 cells are IB3 cells expressing wtCFTR. The experimental focus is to elucidate the etiology of the glycosylation changes seen in Cystic Fibrosis (CF) cells and the mechanism by which these changes are reversed by wild type CFTR gene transfer. To do so, the gene expression of immortalized and primary CF and non-CF airway epithelial cells were compared and studied. Cell lines used were CF/T43 and BEAS-2B, both widely used immortalized airway cell lines. Other cell lines studied included C38 cell lines (clonal derivatives of IB3 cells expressing wtCFTR).
Project description:During airway infection, upregulation of proinflammatory cytokines and subsequent immune cell recruitment is essential to mitigate bacterial infection. Conversely, during prolonged and non-resolving airway inflammation, neutrophils contribute to tissue damage and remodeling. This occurs during diseases including cystic fibrosis (CF) and COPD where bacterial pathogens, not least Pseudomonas aeruginosa, contribute to disease progression through long-lasting infections. Tartrate-resistant acid phosphatase (TRAP) 5 is a metalloenzyme expressed by alveolar macrophages and one of its target substrates is the phosphoglycoprotein osteopontin (OPN). In this study, we found that TRAP5-/- mice had impaired clearance of P. aeruginosa airway infection and reduced recruitment of immune cells. TRAP5 knockdown using siRNA resulted in a decreased activation of the proinflammatory transcription factor NF‐B in reporter mice and a subsequent decrease of proinflammatory gene expression. Add‐back experiments of enzymatically active TRAP5 to TRAP5-/- mice restored immune cell recruitment and bacterial killing. In human CF lung tissue, TRAP5 of alveolar macrophages was detected in proximity to OPN to a higher degree than in normal lung tissue, indicating possible interactions. Taken together, the findings of this study suggest a key role for TRAP5 in modulating airway inflammation. This could have bearing in diseases such as CF and COPD where excessive sterile inflammation could be targeted by pharmacological inhibitors of TRAP5.
Project description:Production of functional proteins requires multiple steps including gene transcription and post-translational processing. MicroRNAs (miRNA) can regulate individual stages of these processes. Despite the importance of the cystic fibrosis transmembrane conductance regulator (CFTR) channel for epithelial anion transport, how its expression is regulated remains uncertain. We discovered that microRNA-138 regulates CFTR expression through its interactions with the transcriptional regulatory protein SIN3A. Treating airway epithelia with a miR-138 mimic increased CFTR mRNA and also enhanced CFTR abundance and transepithelial Cl- permeability independently of elevated mRNA levels. A miR-138 anti-miR had the opposite effects. Importantly, miR-138 altered the expression of many genes encoding proteins that associate with CFTR and may influence its biosynthesis. The most common CFTR mutation, M-NM-^TF508, causes protein misfolding, degradation, and cystic fibrosis. Remarkably, manipulating the miR-138 regulatory network also improved biosynthesis of CFTR-M-NM-^TF508 and restored Cl- transport to cystic fibrosis airway epithelia. This novel miRNA-regulated network directs gene expression from the chromosome to the cell membrane, indicating that an individual miRNA can control a cellular process broader than previously recognized. This discovery also provides new therapeutic avenues for restoring CFTR function to cells affected by the most common cystic fibrosis mutation. 12 samples of Calu-3 cells representing different interventions.