G-CSF and GM-CSF Modify Neutrophil Functions at Concentrations found in Cystic Fibrosis

Stefano Castellani,Susanna D’Oria,Massimo Conese,Angela Vinella,Sante Di Gioia,Pasqualina Montemurro,Maria Favia,Domenica De Venuto,Giuseppina Leonetti,Maria Addolorata Mariggiò,Anna Diana,Lorenzo Guerra,Angela Maria Polizzi,Crescenzio Gallo

doi:10.1038/s41598-019-49419-z

Abstract

The role of colony stimulating factors (CSFs) in cystic fibrosis (CF) circulating neutrophils has not been thoroughly evaluated, considering that the neutrophil burden of lung inflammation in these subjects is very high. The aim of this study was to assess granulocyte-CSF (G-CSF) and granulocyte-macrophage-CSF (GM-CSF) levels in CF patients in various clinical conditions and how these cytokines impact on activation and priming of neutrophils. G-CSF and GM-CSF levels were measured in sputum and serum samples of stable CF patients (n = 21) and in CF patients with acute exacerbation before and after a course of antibiotic therapy (n = 19). CSFs were tested on non CF neutrophils to investigate their effects on reactive oxygen species (ROS) production, degranulation (CD66b, elastase, lactoferrin, MMP-9), and chemotaxis. At very low concentrations found in CF patients (0.005–0.1 ng/ml), both cytokines inhibited ROS production, while higher concentrations (1–5 ng/ml) exerted a stimulatory effect. While either CSF induced elastase and MMP-9 secretion, lactoferrin levels were increased only by G-CSF. Chemotaxis was inhibited by GM-CSF, but was increased by G-CSF. However, when present together at low concentrations, CSFs increased basal and fMLP-stimulated ROS production and chemotaxis. These results suggest the CSF levels that circulating neutrophils face before extravasating into the lungs of CF patients may enhance their function contributing to the airway damage.

Highlights

P-value **stable vs pre **pre vs. post *pre vs. post **stable vs. pre **pre vs. post ***stable vs pre damage to the airway epithelial cells, whilst the secretion of granule proteases, such as elastase, is involved in the degradation of extracellular matrix protein of bronchioles, determining bronchiectasis, and further worsening the mucociliary clearance
GM-colony stimulating factors (CSFs) and G-CSF levels were measured in serum of CF patients in stable condition and their ratio identified patients with chronic P. aeruginosa infection versus those with no chronic infection[17,18]
A direct comparison of results obtained in these studies with ours cannot be made, since almost all patients were chronically infected with S. aureus, P. aeruginosa or B. cepacia, CSFs levels in CF patients reported in this study are quite in good agreement with those previously found

Summary

Introduction

P-value **stable vs pre **pre vs. post *pre vs. post **stable vs. pre **pre vs. post ***stable vs pre damage to the airway epithelial cells, whilst the secretion of granule proteases, such as elastase, is involved in the degradation of extracellular matrix protein of bronchioles, determining bronchiectasis, and further worsening the mucociliary clearance. We have aimed to quantify serum and sputum CSF levels in a cohort of stable CF patients and compare them with those of CF subjects in acute exacerbation and to elucidate whether they are modified by a course of antibiotic therapy. Based on these results, we have studied the effect of GM-CSF and G-CSF on various neutrophil functions, including oxidative burst, degranulation, and chemotaxis. We chose to carry out this experimental part on non CF neutrophils to avoid biases linked to pre-exposure of CF neutrophils to a systemic inflammatory milieu as has been demonstrated in these patients[24]

Objectives

Methods

Results

Conclusion