Modulation of macrophage polarization and function in patients with cystic fibrosis by mutation-independent immunomodulatory compounds

Abstract

Introduction/Aim: Progressive lung disease is the major killer of patients with cystic fibrosis (CF). Macrophages with their pro-inflammatory M1 and anti-inflammatory M2 phenotypes play key roles in initiation and resolution of pulmonary inflammation. We previously reported CFTRdependent fundamental defect in M2 macrophage polarization from patients with CF that may underlie the exaggerated lung inflammation in CF. Inhibition of CFTR in healthy macrophages mimics CF phenotype. Azithromycin (AZM), a macrolide antibiotic, is used in CF to modulate pulmonary inflammation, but the mechanism is unknown. We aimed to restore anti-inflammatory M2 macrophage polarization using mutationindependent biologic compounds. Methods: Monocytes were sorted from the blood from healthy donors (n = 5) and differentiated to macrophages and polarized into M1 and M2 macrophages by LPS and IL-13 respectively, in presence or absence of CFTR inhibitor (C-172) and azithromycin (AZM). Frequency of CD80+ M1 macrophages and CD209+ M2 macrophages were analysed by flow cytometry and function of these polarized macrophages assessed. Results: AZM has no effect on macrophage differentiation and polarization. Incubation with C-172 reduced the percentage of CD209+ M2 macrophages. Interestingly, the addition of AZM restored CD209+ M2 macrophages when C-172 was treated compared to C-172 treated cells only. Macrophages conditioned in AZM plus C-172 medium showed enhanced endocytic ability compared those conditioned in C-172 only. AZM+C-172 reduced the percent of CD80+ M1 macrophages, reduced TNF-α secretion compared to C-172 alone. While, C-172 reduced phagocytic function of M1 macrophages, AZM did not restore phagocytosis of C-172 treated M1 macrophages. Conclusion: Our preliminary data showed restoration of antiinflammatory M2 macrophage polarization and reduced frequencies of M1 macrophages in CFTR-inhibited macrophages following AZM treatment. These modulations of macrophage polarization and functions is mutationindependent and show a scope of treating patients with CF with nonantibiotic macrolides, which will reduce the chance of antibiotic resistance.L6269406982019-04-02 <br />