A physical linkage between cystic fibrosis airway surface dehydration and Pseudomonas aeruginosa biofilms

A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that interacts with P. aeruginosa to promote biofilms. To model CF vs. normal airway infections, normal (2.5% solids) and CF-like concentrated (8% solids) mucus were prepared, placed in flat chambers, and infected with an ≈5 × 103 strain PAO1 P. aeruginosa. Although bacteria grew to 1010 cfu/ml in both mucus concentrations, macrocolony formation was detected only in the CF-like (8% solids) mucus. Biophysical and functional measurements revealed that concentrated mucus exhibited properties that restrict bacterial motility and small molecule diffusion, resulting in high local bacterial densities with high autoinducer concentrations. These properties also rendered secondary forms of antimicrobial defense, e.g., lactoferrin, ineffective in preventing biofilm formation in a CF-like mucus environment. These data link airway surface liquid hyperabsorption to the high incidence of P. aeruginosa biofilms in CF via changes in the hydration-dependent physical–chemical properties of mucus and suggest that the thickened mucus gel model will be useful to develop therapies of P. aeruginosa biofilms in CF airways.

[1]  S. Randell,et al.  Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces1 , 2005, The Journal of Immunology.

[2]  U. Römling,et al.  Microcolony formation: a novel biofilm model of Pseudomonas aeruginosa for the cystic fibrosis lung. , 2005, Journal of medical microbiology.

[3]  S. Randell,et al.  Mucins and their O-Glycans from human bronchial epithelial cell cultures. , 2004, American journal of physiology. Lung cellular and molecular physiology.

[4]  Richard C Boucher,et al.  Increased airway epithelial Na+ absorption produces cystic fibrosis-like lung disease in mice , 2004, Nature Medicine.

[5]  D. Wirtz,et al.  Enhanced Viscoelasticity of Human Cystic Fibrotic Sputum Correlates with Increasing Microheterogeneity in Particle Transport* , 2003, Journal of Biological Chemistry.

[6]  T. Hardingham,et al.  Calcium-dependent Protein Interactions in MUC5B Provide Reversible Cross-links in Salivary Mucus* , 2003, Journal of Biological Chemistry.

[7]  George M. Hilliard,et al.  Pseudomonas aeruginosa anaerobic respiration in biofilms: relationships to cystic fibrosis pathogenesis. , 2002, Developmental cell.

[8]  J. Emerson,et al.  Pseudomonas aeruginosa and other predictors of mortality and morbidity in young children with cystic fibrosis , 2002, Pediatric pulmonology.

[9]  L. Holmberg,et al.  Predictors of deterioration of lung function in cystic fibrosis * , 2002, Pediatric pulmonology.

[10]  E. Greenberg,et al.  A component of innate immunity prevents bacterial biofilm development , 2002, Nature.

[11]  Frederick M. Ausubel,et al.  Pseudomonas biofilm formation and antibiotic resistance are linked to phenotypic variation , 2002, Nature.

[12]  J. Costerton,et al.  Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms , 2002, Clinical Microbiology Reviews.

[13]  T. Ganz.  Antimicrobial polypeptides in host defense of the respiratory tract. , 2002, The Journal of clinical investigation.

[14]  Richard C Boucher,et al.  Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patients. , 2002, The Journal of clinical investigation.

[15]  D. Thornton,et al.  Heterogeneity of airways mucus: variations in the amounts and glycoforms of the major oligomeric mucins MUC5AC and MUC5B. , 2002, The Biochemical journal.

[16]  R. Tarran,et al.  The CF salt controversy: in vivo observations and therapeutic approaches. , 2001, Molecular cell.

[17]  B. Iglewski,et al.  Quorum-Sensing Genes in Pseudomonas aeruginosa Biofilms: Their Role and Expression Patterns , 2001, Applied and Environmental Microbiology.

[18]  Matthew R. Parsek,et al.  Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms , 2000, Nature.

[19]  Thomas G. Mason,et al.  Estimating the viscoelastic moduli of complex fluids using the generalized Stokes–Einstein equation , 2000 .

[20]  B. Iglewski,et al.  Novel synthetic analogs of the Pseudomonas autoinducer. , 1999, Bioorganic & medicinal chemistry letters.

[21]  S. Randell,et al.  Evidence for Periciliary Liquid Layer Depletion, Not Abnormal Ion Composition, in the Pathogenesis of Cystic Fibrosis Airways Disease , 1998, Cell.

[22]  S. Randell,et al.  Coordinated clearance of periciliary liquid and mucus from airway surfaces. , 1998, The Journal of clinical investigation.

[23]  J. Costerton,et al.  The involvement of cell-to-cell signals in the development of a bacterial biofilm. , 1998, Science.

[24]  M. Knowles,et al.  Ion composition of airway surface liquid of patients with cystic fibrosis as compared with normal and disease-control subjects. , 1997, The Journal of clinical investigation.

[25]  Denis Wirtz,et al.  Particle Tracking Microrheology of Complex Fluids , 1997 .

[26]  F. MacKintosh,et al.  Microscopic Viscoelasticity: Shear Moduli of Soft Materials Determined from Thermal Fluctuations , 1997, cond-mat/9709228.

[27]  B. Iglewski,et al.  Roles of Pseudomonas aeruginosa las and rhl quorum-sensing systems in control of elastase and rhamnolipid biosynthesis genes , 1997, Journal of bacteriology.

[28]  C. Clavel,et al.  Revisited physicochemical and transport properties of respiratory mucus in genotyped cystic fibrosis patients. , 1997, American journal of respiratory and critical care medicine.

[29]  E. Greenberg,et al.  Structure of the autoinducer required for expression of Pseudomonas aeruginosa virulence genes. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[30]  M. King,et al.  Amiloride inhalation therapy in cystic fibrosis. Influence on ion content, hydration, and rheology of sputum. , 1993, The American review of respiratory disease.

[31]  C. Mellis,et al.  Mucoid Pseudomonas aeruginosa is a marker of poor survival in cystic fibrosis , 1992, Pediatric pulmonology.

[32]  B. Iglewski,et al.  Transformation of Pseudomonas aeruginosa by electroporation. , 1989, Nucleic acids research.

[33]  R. Baltimore,et al.  Immunohistopathologic localization of Pseudomonas aeruginosa in lungs from patients with cystic fibrosis. Implications for the pathogenesis of progressive lung deterioration. , 1989, The American review of respiratory disease.

[34]  B. Holloway,et al.  Chromosomal genetics of Pseudomonas. , 1979, Microbiological reviews.

[35]  R N Doetsch,et al.  Effect of Viscosity on Bacterial Motility , 1974, Journal of bacteriology.

[36]  W. Hamlin,et al.  A new method for serum iron and total iron-binding capacity by atomic absorption spectrophotometry. , 1969, Clinical chemistry.

[37]  J. L. Potter,et al.  STUDIES ON PULMONARY SECRETIONS. I. THE OVER-ALL CHEMICAL COMPOSITION OF PULMONARY SECRETIONS FROM PATIENTS WITH CYSTIC FIBROSIS, BRONCHIECTASIS, AND LARYNGECTOMY. , 1963, The American review of respiratory disease.

[38]  G. Barbero,et al.  Composition of tracheobronchial secretions in cystic fibrosis of the pancreas and bronchiectasis. , 1959, Pediatrics.

[39]  B. Christensen,et al.  Molecular tools for study of biofilm physiology. , 1999, Methods in enzymology.

[40]  L. Reid,et al.  Bronchial mucus in health and disease. , 1978, British medical bulletin.