A Novel Lipidomic Strategy Reveals Plasma Phospholipid Signatures Associated with Respiratory Disease Severity in Cystic Fibrosis Patients

Ida Chiara Guerrera,Daniele Piomelli,Dorota Sands,Isabelle Sermet-Gaudelus,Julien Colas,Anna Nowakowska,Martin Schuerenberg,Giuseppe Astarita,Aleksander Edelman,Mario Ollero,Jean-Philippe Jais,Amit Gaggar

doi:10.1371/journal.pone.0007735

Abstract

The aim of this study was to search for lipid signatures in blood plasma from cystic fibrosis (CF) patients using a novel MALDI-TOF-ClinProTools™ strategy, initially developed for protein analysis, and thin layer chromatography coupled to MALDI-TOF (TLC-MALDI). Samples from 33 CF patients and 18 healthy children were subjected to organic extraction and column chromatography separation of lipid classes. Extracts were analyzed by MALDI-TOF, ion signatures were compared by the ClinProTools™ software and by parallel statistical analyses. Relevant peaks were identified by LC-MSn. The ensemble of analyses provided 11 and 4 peaks differentially displayed in CF vs healthy and in mild vs severe patients respectively. Ten ions were significantly decreased in all patients, corresponding to 4 lysophosphatidylcholine (18∶0, 18∶2, 20∶3, and 20∶5) and 6 phosphatidylcholine (36∶5, O-38∶0, 38∶4, 38∶5, 38∶6, and P-40∶1) species. One sphingolipid, SM(d18∶0), was significantly increased in all patients. Four PC forms (36∶3, 36∶5, 38∶5, and 38∶6) were consistently downregulated in severe vs mild patients. These observations were confirmed by TLC-MALDI. These results suggest that plasma phospholipid signatures may be able to discriminate mild and severe forms of CF, and show for the first time MALDI-TOF-ClinProTools™ as a suitable methodology for the search of lipid markers in CF.

Highlights

Cystic fibrosis (CF) is characterized by a vicious circle of chronic inflammation in pulmonary airways and recurrent exacerbations, usually concomitant with bacterial infections [1,2,3]
Group comparisons by ClinProToolsTM resulted in the detection of 18 ion peaks, all of them corresponding to the phospholipid fraction analyzed in positive mode, differentially displayed with p-values,0.05 (Table 2)
Differences were established between CF vs non-CF children (14 peaks) and between patients showing mild vs severe pulmonary disease (7 peaks)

Summary

Introduction

Cystic fibrosis (CF) is characterized by a vicious circle of chronic inflammation in pulmonary airways and recurrent exacerbations, usually concomitant with bacterial infections [1,2,3]. These manifestations account for the most part of morbidity and mortality associated with the disease. IL-8, cleaved alpha-antitrypsin, and S100A8 (or CF antigen), have been found in sputum as predictors of pulmonary exacerbations [6], or associated with the presence of CFTR mutations [7,8], in addition to proteomic signatures in serum corresponding to inflammation markers [9]. Concerning lipids, imbalances in fatty acid profiles [14,15,16,17], and other lipid moieties (reviewed in [18,19]) in CF patients and models have been consistently reported, no systematic search by comprehensive lipidomic techniques has been performed to date

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Conclusion