Airway epithelial cell inflammatory signalling in cystic fibrosis (original) (raw)
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Proceedings of the National Academy of Sciences, 2008
Blood neutrophils recruited to cystic fibrosis (CF) airways are believed to be rapidly killed by resident bacteria and to passively release elastase and other toxic by-products that promote disease progression. By single-cell analysis, we demonstrate that profound functional and signaling changes readily occur within viable neutrophils recruited to CF airways, compared with their blood counterparts. Airway neutrophils have undergone conventional activation, as shown by decreased intracellular glutathione, increased lipid raft assembly, surface mobilization of CD11b؉ and CD66b؉ granules, and increased levels of the cytoskeleton-associated phospho-Syk kinase. Unexpectedly, they also mobilize to the surface CD63؉ elastase-rich granules, usually confined intracellularly, and lose surface expression of CD16 and CD14, both key receptors in phagocytosis. Furthermore, they express CD80, major histocompatibility complex type II, and the prostaglandin D2 receptor CD294, all normally associated with other lineages, which reflects functional reprogramming. This notion is reinforced by their decreased total phosphotyrosine levels, mirroring a postactivated stage, and increased levels of the phospho-S6 ribosomal protein, a key anabolic switch. Thus, we identified a subset of neutrophils within CF airways with a viable but dysfunctional phenotype. This subset provides a possible therapeutic target and indicates a need to revisit current paradigms of CF airway disease.
The Role of Inflammation in the Pathophysiology of CF Lung Disease
Clinical Reviews in Allergy & Immunology, 2002
Cystic fibrosis (CF) lung disease is characterized by a self-perpetuating cycle of airway obstruction, chronic bacterial infection, and vigorous inflammation that results in structural damage to the airway. CF patients have a predilection for infection with a limited spectrum of distinctive bacteria that initiate a vigorous inflammatory response which is more harmful than protective. The airway epithelial cell, which normally expresses the cystic fibrosis transmembrane conductance regulator (CFTR), directs the inflammatory response. Defects in CFTR are associated with increased production of proinflammatory mediators including IL-8, a potent neutrophil chemoattractant that stimulates the influx of massive numbers of neutrophils into the airways. These neutrophils are the primary effector cells responsible for the pathological manifestations of CF lung disease. Documented deficiencies in immunoregulatory molecules such as IL-10 likely contribute to the generation of the excessive and persistent inflammatory response. Since inflammation is a key contributor to the pathogenesis of CF lung disease, anti-inflammatory therapy must assume a larger role in CF until a cure is discovered. To date, attention has focused primarily on the therapeutic potential of systemic and inhaled corticosteroids and the non-steroidal antiinflammatory drug (NSAID) ibuprofen. Development of new anti-inflammatory therapies that impact intracellular signaling pathways and cell-cell communication molecules likely will have the greatest impact on limiting 5
AJP: Lung Cellular and Molecular Physiology, 2007
We tested whether cystic fibrosis (CF) airway epithelia have larger innate immune responses than non-CF or CFTR-corrected cells, perhaps resulting from ER stress due to retention of )F508CFTR in the endoplasmic reticulum (ER) and activation of Ca 2+ (Ca i ) and NF-B signaling. Adenovirus (adv) infections of a human cystic fibrosis ()F508/)F508) nasal cell line (CF15) provided isogenic comparisons of wtCFTR and )F508CFTR. In the absence of bacteria, there were no or only small differences among CF15, CF15-lacZ ( -galactosidase-expressing), CF15-wtCFTR (wtCFTR-corrected) and CF15-)F508CFTR (to test ER retention of )F508CFTR) cells in: NF-B activity, IL8 secretion, Ca i responses and ER stress. Non-CF and CF primary cultures of human bronchial epithelial cells (HBE) secreted IL8 equivalently. Upon infection with Pseudomonas aeruginosa (PA) or flagellin (key activator for airway epithelia), CF15, CF15-lacZ, CF15-wtCFTR and CF15)F508CFTR cells exhibited equal PA binding, NF-B activity and IL8 secretion; cells also responded similarly to flagellin when both CFTR (forskolin) and Ca i signaling (ATP) were activated. CF and non-CF HBE responded similarly to flagellin+ATP. Thapsigargin (Tg, releases ER Ca 2+ ) increased flagellin-stimulated NF-B and ER stress similarly in all cells. We conclude that ER stress, Ca i and NF-B signaling and IL8 secretion were unaffected by wt-or )F508CFTR in control and during exposure to PA, flagellin, flagellin+ATP or flagellin+ATP+forskolin. Tg, but not wt-or )F508CFTR, triggered ER stress.
Molecular Medicine, 2001
Background: Cystic fibrosis (CF) is the most common, lethal autosomal recessive disease affecting children in the United States and Europe. Extensive work is being performed to develop both gene and drug therapies. The principal mutation causing CF is in the CFTR gene ([⌬F508]CFTR). This mutation causes the mutant protein to traffic poorly to the plasma membrane, and degrades CFTR chloride channel activity. CPX, a candidate drug for CF, binds to mutant CFTR and corrects the trafficking deficit. CPX also activates mutant CFTR chloride channel activity. CF airways are phenotypically inundated by inflammatory signals, primarily contributed by sustained secretion of the proinflammatory cytokine interleukin 8 (IL-8) from mutant CFTR airway epithelial cells. IL-8 production is controlled by genes from the TNF-␣R/NFB pathway, and it is possible that the CF phenotype is due to dysfunction of genes from this pathway. In addition, because drug therapy with CPX and gene therapy with CFTR have the same common endpoint of raising the levels of CFTR, we have hypothesized that either approach should have a common genomic endpoint. Materials and Methods: To test this hypothesis, we studied IL-8 secretion and global gene expression in IB-3 CF lung epithelial cells. The cells were treated by either gene therapy with wild-type CFTR, or by pharmacotherapy with the CFTR-surrogate drug CPX. CF cells, treated with either CFTR or CPX, were also exposed to Pseudomonas aeruginosa, a common chronic pathogen in CF patients. cDNA microarrays were used to assess global gene expression under the different conditions. A novel bioinformatic algorithm (GENESAVER) was developed to identify genes whose expression paralleled secretion of IL-8. Results: We report here that IB3 CF cells secrete massive levels of IL-8. However, both gene therapy with CFTR and drug therapy with CPX substantially suppress IL-8 secre
Chronic Inflammation in the Cystic Fibrosis Lung: Alterations in Inter- and Intracellular Signaling
Clinical Reviews in Allergy & Immunology, 2008
A vicious cycle of airway obstruction, infection, and inflammation continues to cause most of the morbidity and mortality in cystic fibrosis (CF). Mutations that result in decreased expression or function of the membrane Cl − channel, cystic fibrosis transmembrane regulator (CFTR), result in a decrease in the volume (and hence the depth) of liquid on the airway surface, impaired ciliary function, and dehydrated glandular secretions. In turn, these abnormalities contribute to a milieu, which promotes chronic infection with a limited but unique spectrum of microorganisms. Defects in CFTR also perturb regulation of several intracellular signaling pathways including signal transducers and activator of transcription, I-κB and nuclear factor-kappa B, and low molecular weight GTPases. Together, these abnormalities result in excessive production of NF-κB dependent cytokines such as interleukin (IL)-1, tumor necrosis factor (TNF), IL-6, and IL-8. There are decreased responses to interferon gamma and transforming growth factor beta leading to decreased production of iNOS and NO. Abnormalities of lipid mediators and decreased secretion of counter/regulatory cytokines have also been reported. Together, these effects combine to create a chronic inflammatory process, which damages and obstructs the airways, and eventually claims the life of the patient.
Journal of Cystic Fibrosis, 2003
The pathological hallmark of cystic fibrosis (CF) chronic inflammatory response is the massive neutrophil influx into the airways. This dysregulated neutrophil emigration may be caused by the abnormal secretion of chemoattractants by respiratory epithelial cells and polarised lymphocyte T-helper response. Neutrophils from CF patients have a different response to inflammatory mediators than neutrophils from normal subjects, indicating that they are primed in vivo before entering the CF airways. CF neutrophils secrete more myeloperoxidase and elastase, mobilise less opsonin receptors and release less L-selectin than non-CF neutrophils. Moreover, they show altered cytokine production and a dysregulated chemotaxis response. Laboratory studies now suggest that CFTR is involved in regulating some neutrophil functions and indicate that altered properties of CF neutrophils may depend on genetic factors. Current gene therapy approaches are targeted to the respiratory epithelium, but many hurdles oppose an efficient and efficacious CFTR gene transfer. The possibility of CFTR gene therapy-based approach targeting CF neutrophils at the hematopoietic stem cell level is discussed.