ABSTRACT
It is unclear whether inflammation in the cystic fibrosis (CF) lung relates predominantly to bacterial infection, or occurs as a direct consequence of mutant cystic fibrosis transmembrane conductance regulator (CFTR) protein. Interleukin (IL)-8 secretion from CF and non-CF cell lines, and from CF and non-CF human primary nasal epithelial cells incubated with or without Pseudomonas aeruginosa, was measured. Activation of nuclear factor-kappaB (NF-kappaB) in unstimulated CF and non-CF nasal epithelial cells, cell lines and murine tissues was measured by gel-shift assays. No significant difference in basal IL-8 production or NF-kappaB activation was observed between CF and non-CF primary nasal cells. However, CF cells exhibited a significantly (p<0.01) increased IL-8 secretion following P. aeruginosa stimulation. Equalization of the increased P. aeruginosa adherence observed in CF cells, to non-CF levels, resulted in comparable IL-8 secretion. Further, IL-8 production did not differ with mutations which result in either correctly localized CFTR, or in partial/total mislocalization of this protein. Similar levels of NF-kappaB activation were observed in a number of organs of wildtype and CF mice. Finally, IL-8 secretion and NF-kappaB activity were not consistently increased in CF cell lines. Cos-7 cell transfection with plasmids expressing deltaF508 or G551D mutant CFTR protein resulted in increased activation of a p50-containing NF-kappaB complex, but IL-8 secretion was similar to wild-type cells. The authors conclude that the stimulus produced by Pseudomonas aeruginosa is the predominant inflammatory trigger in their models.
Subject(s)
Bacterial Adhesion/physiology , Cystic Fibrosis Transmembrane Conductance Regulator/physiology , Cystic Fibrosis/microbiology , Cystic Fibrosis/pathology , Interleukin-8/biosynthesis , Lung/pathology , Pseudomonas aeruginosa/physiology , Adolescent , Adult , Animals , Bacterial Infections/complications , Bacterial Infections/pathology , Bronchi/cytology , Bronchi/metabolism , COS Cells/metabolism , Cell Line , Cells, Cultured , Cystic Fibrosis/complications , Cystic Fibrosis/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/metabolism , Female , Genotype , Humans , Inflammation , Lung/metabolism , Lung/microbiology , Male , Mice , Mice, Inbred CFTR , Middle Aged , Mutation , NF-kappa B/genetics , NF-kappa B/metabolism , Nasal Mucosa/metabolism , Nasal Mucosa/microbiology , Respiratory Mucosa/metabolism , Respiratory Mucosa/microbiology , Trachea/cytology , Trachea/metabolism , Transcriptional Activation , Transfection , beta-Galactosidase/geneticsABSTRACT
Using the novel mathematical technique known as wavelet analysis, a new method (WSC) is presented to sort spikes according to a decomposition of neural signals in the time-frequency space. The WSC method is implemented by a pyramidal algorithm that acts upon neural signals as a bank of quadrature mirror filters. This algorithm is clearly explained and an overview of the mathematical background of wavelet analysis is given. An artificial spike train, especially designed to test the specificity and sensibility of sorting procedures, was used to assess the performance of the WSC method as well as of methods based on principal component analysis (PCA) and reduced feature set (RFS). The WSC method outperformed the other two methods. Its superior performance was largely due to the fact that spike profiles that could not be separated by previous methods (because of the similarity of their temporal profile and the masking action of noise) were separable by the WSC method. The WSC method is particularly noise resistant, as it implicitly eliminates the irrelevant information contained in the noise frequency range. But the main advantage of the WSC method is its use of parameters that describe the joint time-frequency localization of spike features to build a fast and unspecialized pattern recognition procedure.
