Abstract
Introduction: Purinergic signalling is implicated in the pathomechanism of COPD, however the contribution of individual P2 receptors to airway inflammation is not fully elucidated.
Aim: To study messenger RNA expression of P2 receptors in sputum cells from patients with COPD and control subjects.
Methods: Induced or spontaneous sputum from control smoking/ex-smoking subjects (n=17, >10 pack-years) and patients with stable COPD (mild-moderate: n=16, severe-very severe: n=19) was collected and processed with 0.1% dithiotreitol. Quantitative polymerase chain reaction was carried out for P2X1, P2X4, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, P2Y14 receptor messenger RNA of sputum cells (Taqman, 480 Lightcycler). Gene transcription relative to β2-microglobulin transcription was analysed with non-parametric tests.
Results: The relative expression of P2Y14 was elevated in sputum cells from patients with mild-moderate and severe-very severe COPD in comparison with control subjects (p<0.01 and p<0.001; respectively) while showing a positive correlation to sputum neutrophil count (p<0.01, r=0.46). P2Y1 transcription was decreased in patients with severe-very severe COPD (vs. control p<0.01). The expressions of P2Y11 and P2Y12 receptors were lower in severe-very severe patients compared to control subjects and patients with mild-moderate disease (all comparisons: p<0.01), and inversely correlated to sputum neutrophil percentage (all relations: p<0.01; r=0.-74 and r=0.-51, respectively).
Conclusion: Patients with COPD show an altered messenger RNA expression profile of P2 receptors in sputum cells. Further studies should clarify the functional roles of P2 receptors in airway inflammation in COPD.
- © 2014 ERS