Refinement of metabolite detection in cystic fibrosis sputum reveals heme correlates with lung function decline

Autoři: Nathaniel R. Glasser aff001;  Ryan C. Hunter aff002;  Theodore G. Liou aff003;  Dianne K. Newman aff001
Působiště autorů: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America aff001;  Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, United States of America aff002;  The Center for Quantitative Biology and The Adult Cystic Fibrosis Center, Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America aff003
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article


The bacterial growth environment within cystic fibrosis (CF) sputum is complex, dynamic, and shaped by both host and microbial processes. Characterization of the chemical parameters within sputum that stimulate the in vivo growth of airway pathogens (e.g. Pseudomonas aeruginosa) and their associated virulence factors may lead to improved CF treatment strategies. Motivated by conflicting reports of the prevalence and abundance of P. aeruginosa-derived metabolites known as phenazines within CF airway secretions, we sought to quantify these metabolites in sputum using quadrupole time-of-flight mass spectrometry. In contrast to our previous work, all phenazines tested (pyocyanin (PYO), phenazine-1-carboxylic acid (PCA), phenazine-1-carboxamide, and 1-hydroxyphenazine) were below detection limits of the instrument (0.1 μM). Instead, we identified a late-eluting compound that shared retention time and absorbance characteristics with PCA, yet generated mass spectra and a fragmentation pattern consistent with ferriprotoporphyrin IX, otherwise known as heme B. These data suggested that UV-vis chromatographic peaks previously attributed to PCA and PYO in sputum were mis-assigned. Indeed, retrospective analysis of raw data from our prior study found that the heme B peak closely matched the peaks assigned to PCA, indicating that the previous study likely uncovered a positive correlation between pulmonary function (percent predicted forced expiratory volume in 1 second, or ppFEV1) and heme B, not PCA or any other phenazine. To independently test this observation, we performed a new tandem mass-spectrometry analysis of 71 additional samples provided by the Mountain West CF Consortium Sputum Biomarker study and revealed a positive correlation (ρ = −0.47, p<0.001) between sputum heme concentrations and ppFEV1. Given that hemoptysis is strongly associated with airway inflammation, pulmonary exacerbations and impaired lung function, these new data suggest that heme B may be a useful biomarker of CF pathophysiology.

Klíčová slova:

Cystic fibrosis – Heme – High performance liquid chromatography – Metabolites – principal component analysis – Pseudomonas aeruginosa – Pulmonary function – Sputum


1. Harrison F. Microbial ecology of the cystic fibrosis lung. Microbiol. 2007;153:917–23. doi: 10.1099/mic.0.2006/004077-0 17379702

2. Aaron SD, Stephenson AL, Cameron DW, Whitmore GA. A statistical model to predict one-year risk of death in patients with cystic fibrosis. J Clin Epidemiol. 2015;68:1336–45. doi: 10.1016/j.jclinepi.2014.12.010 25655532

3. Lau GW, Ran H, Kong F, Hassett DJ, Mavrodi D. Pseudomonas aeruginosa pyocyanin is critical for lung infection in mice. Infect Immunity. 2004;72:4275–8. doi: 10.1128/IAI.72.7.4275–4278.2004

4. Quinn RA, Phelan VV, Whiteson KL, Garg N, Bailey BA, Lim YW, et al. Microbial, host and xenobiotic diversity in the cystic fibrosis sputum metabolome. ISME J. 2015;10:1483–98. doi: 10.1038/ismej.2015.207 26623545

5. Wilson R, Sykes DA, Watson D, Rutman A, Taylor GW, Cole PJ. Measurement of Pseudomonas aeruginosa phenazine pigments in sputum and assessment of their contribution to sputum sol toxicity for respiratory epithelium. Infect Immun. 1988;56:2515–7. 3137173

6. Hunter RC, Klepac-Ceraj V, Lorenzi MM, Grotzinger H, Martin TR, Newman DK. Phenazine content in the cystic fibrosis respiratory tract negatively correlates with lung function and microbial complexity. Am J Resp Cell Mol Biol 2012;47:738–45. doi: 10.1165/rcmb.2012-0088OC 22865623

7. Liou TG, Adler FR, Argel N, Asfour F, Brown PS, Chatfield BA, et al. Prospective multicenter randomized patient recruitment and sample collection to enable future measurements of sputum biomarkers of inflammation in an observational study of cystic fibrosis. BMC Med Res Method 2019;19:88. doi: 10.1186/s12874-019-0705-0 31027503

8. Liou TG, Adler FR, FitzSimmons SC, Cahill BC, Hibbs JR, Marshall BC. Predictive 5-year survivorship model of cystic fibrosis. Am. J. Epidemiol. 2001;153:345–52. doi: 10.1093/aje/153.4.345 11207152

9. Rubin DB. Inference and missing data. Biometrika. 1976;64:581–592. doi: 10.2307/2335739

10. Létoffé S, Heuck G, Delepelaire P, Lange N, Wandersman C. Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact. Proc Nat Acad Sci USA. 2009;106(28):11719–24. doi: 10.1073/pnas.0903842106 19564607

11. Morrison DB, Williams EF. The solubility and titration of hemin and ferrihemic acid. J Biol Chem. 1941;137:461–73.

12. Jorth P, Staudinger BJ, Wu X, Hisert KB, Hayden H, Garudathri J, et al. Regional Isolation Drives Bacterial Diversification within Cystic Fibrosis Lungs. Cell Host Microb. 2015;18:307–19. doi: 10.1016/j.chom.2015.07.006 26299432

13. Cowley ES, Kopf SH, LaRiviere A, Ziebis W, Newman DK. Pediatric cystic fibrosis sputum can be chemically dynamic, anoxic, and extremely reduced due to hydrogen sulfide formation. mBio. 2015;6:e00767–15. doi: 10.1128/mBio.00767-15 26220964

14. Fuchs HJ, Borowitz DS, Christiansen DH, Morris EM, Nash ML, Ramsey BW, et al. Effect of aerosolized recombinant human DNase on exacerbations of respiratory symptoms and on pulmonary function in patients with cystic fibrosis. N Engl J Med. 1994;331:637–42. doi: 10.1056/NEJM199409083311003 7503821

15. Das T, Kutty SK, Tavallaie R, Ibugo AI, Panchompoo J, Sehar S, et al. Phenazine virulence factor binding to extracellular DNA is important for Pseudomonas aeruginosa biofilm formation. Sci Rep. 2015;5:8398. doi: 10.1038/srep08398 25669133

16. Rabin HR, Butler SM, Wohl MEB, Geller DE, Colin AA, Schidlow DV, et al. Pulmonary exacerbations in cystic fibrosis. Ped Pulmonol. 2004;37:400–6. doi: 10.1002/ppul.20023 15095322

17. Flume PA, Yankaskas JR, Ebeling M, Hulsey T, Clark LL. Massive hemoptysis in cystic fibrosis. Chest. 2005;128:729–38. doi: 10.1378/chest.128.2.729 16100161

18. Barben JU, Ditchfield M, Carlin JB, Robertson CF, Robinson PJ, Olinsky A. Major haemoptysis in children with cystic fibrosis: a 20-year retrospective study. J Cyst Fib. 2003;2:105–11. doi: 10.1016/S1569-1993(03)00066-3

19. Hunter RC, Asfour F, Dingemans J, Osuna BL, Samad T, Malfroot A, et al. Ferrous iron is a significant component of bioavailable iron in cystic fibrosis airways. mBio. 2013;4(4):e00557–13. doi: 10.1128/mBio.00557-13 23963183

20. Banin E, Vasil ML, Greenberg EP. Iron and Pseudomonas aeruginosa biofilm formation. Proc Nat Acad Sci USA. 2005;102:11076–81. doi: 10.1073/pnas.0504266102 16043697

21. Moreau-Marquis S, O'Toole GA, Stanton BA. Tobramycin and FDA-Approved Iron Chelators Eliminate Pseudomonas aeruginosa Biofilms on Cystic Fibrosis Cells. Am J Resp Cell Mol Biol. 2009;41:305–13. doi: 10.1165/rcmb.2008-0299OC 19168700

22. Cystic Fibrosis Foundation Patient Registry 2017 Annual Data Report. Bethesda, Maryland: Cystic Fibrosis Foundation, 2018.

23. Matsumoto M, Nishimura T. Mersenne Twister: A 623-dimensionally Equidistributed Uniform Pseudo-random Number Generator. ACM Trans Model Comput Simul. 1998;8:3–30. doi: 10.1145/272991.272995

24. Standardization of Spirometry, 1994 Update. American Thoracic Society. Am J Resp Crit Care Med. 1995;152:1107–36. doi: 10.1164/ajrccm.152.3.7663792 7663792

25. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Resp Crit Care Med. 1999;159:179–87. doi: 10.1164/ajrccm.159.1.9712108 9872837

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2019 Číslo 12
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