Mutations in CFTR lead to a complex phenotype that includes increased susceptibility to Pseudomonas infections, a functional deficiency of IL-10, and an exaggerated proinflammatory cytokine response. We examined the effects of CFTR gene correction on the gene expression profile of a CF bronchial epithelial cell line (IB3-1) and determined which CF-related gene expression changes could be reversed by IL-10 expression. We performed microarray experiments to monitor the gene expression profile of three cell lines over a time course of exposure to Pseudomonas. At baseline, we identified 843 genes with statistically different levels of expression in CFTR-corrected (S9) cells compared to the IB3-1 line or the IL-10-expressing line. K-means clustering and functional group analysis revealed a primary up-regulation of ubiquitination enzymes and TNF pathway components and a primary down-regulation of protease inhibitors and protein glycosylation enzymes in CF. Key gene expression changes were confirmed by real-time RT-PCR. Massive reprogramming of gene expression occurred 3 h after Pseudomonas exposure. Changes specific to CF included exaggerated activation of cytokines, blunted activation of anti-proteases, and repression of protein glycosylation enzymes. In conclusion, the CFTR genotype changes the expression of multiple genes at baseline and in response to bacterial challenge, and only a subset of these changes is secondary to IL-10 deficiency.

To gain insight into aberrant cytokine regulation in cystic fibrosis (CF), we compared the phenotypic manifestations of allergen challenge in gut-corrected CFTR-deficient mice with background-matched C57Bl6 (B6) mice. Aspergillus fumigatus (Af) antigen was used to mimic allergic bronchopulmonary aspergillosis, a peculiar hyper-IgE syndrome with a high prevalence in CF patients. CFTRÀ/À, C57BL/6 and FVB/NJ mice were sensitized with Af antigen by serial intraperitoneal injections. Control mice were mock sensitized with PBS. Challenges were performed by inhalation of Af antigen aerosol. After Af antigen challenge, histologic analysis showed goblet cell hyperplasia and lymphocytic infiltration in both strains. However, total serum IgE levels were markedly elevated in CF mice. Sensitized CF mice showed a five-fold greater IgE response to sensitization as compared with B6-and FVB-sensitized controls. Additional littermate controls to fully normalize for B6-FVB admixture in the strain background confirmed the role of CFTR mutation in the hyper-IgE syndrome. Cytokine mRNA levels of IL-5 and GM-CSF in the bronchoalveolar lavage (BAL) fluid, and BAL cell differentials indicated that CFTR mutation caused a shift from an IL-5-predominant to an IL-4-predominant cytokine profile. This system models a very specific type of airway inflammation in CF and could provide insights into pathogenesis and treatment of the disease.

Airway inflammation in allergen-induced asthma is associated with eicosanoid release. These bioactive lipids exhibit anti- and pro-inflammatory activities with relevance to pulmonary pathophysiology. We hypothesized that sensitization/challenge using an extract from the ubiquitous fungus Aspergillus fumigatus in a mouse model of allergic asthma would result in altered phospholipase gene expression, thus modulating the downstream eicosanoid pathway. We observed the most significant induction in the group IVC PLA2 (phospholipase A2) [also known as cPLA2γ (cytosolic PLA2γ) or PLA2G4C]. Our results infer that A. fumigatus extract can induce cPLA2γ levels directly in eosinophils, whereas induction in lung epithelial cells is most likely to be a consequence of TNFα (tumour necrosis factor α) secretion by A. fumigatus-activated macrophages. The mechanism of TNFα-dependent induction of cPLA2γ gene expression was elucidated through a combination of promoter deletions, ChIP (chromatin immunoprecipitation) and overexpression studies in human bronchoepithelial cells, leading to the identification of functionally relevant CRE (cAMP-response element), NF-κB (nuclear factor κB) and E-box promoter elements. ChIP analysis demonstrated that RNA polymerase II, ATF-2 (activating transcription factor 2)-c-Jun, p65-p65 and USF (upstream stimulating factor) 1-USF2 complexes are recruited to the cPLA2γ enhancer/promoter in response to TNFα, with overexpression and dominant-negative studies implying a strong level of co-operation and interplay between these factors. Overall, our results link cytokine-mediated alterations in cPLA2γ gene expression with allergic asthma and outline a complex regulatory mechanism.

Two antagonists of phosphoinositide 3-OH kinases (PI3Ks), LY294002 and Wortmannin, reduced the magnitude of the receptor potential in lobster olfactory receptor neurons (ORNs) recorded by patch clamping the cells in vivo. An antibody directed against the c-terminus of human PI3K-P110 beta detected a molecule of predicted size in the outer dendrites of the ORNs. Two 3-phosphoinositides, PI(3,4)P(2) (1--4 microM) and PI(3,4,5)P(3) (1--4 microM) applied to the cytoplasmic side of inside-out patches taken from cultured lobster ORNs, reversibly activated a Na(+)-gated channel previously implicated in the transduction cascade in these cells. 3-Phosphoinositides were the most effective phosphoinositide (1 microM) in enhancing the open probability of the channel. Collectively, these results implicate 3-phosphoinositides in lobster olfactory transduction and raise the need to consider the 3-phosphoinositide pathway in olfactory transduction.