Impaired functions of macrophage from cystic fibrosis patients: CD11b, TLR-5 decrease and sCD14, inflammatory
Karin Simonin-Le Jeune1, André Le Jeune, Stéphane Jouneau
1Université de Rennes 1, Structure Fédérative de Recherche Biosit, F-35043 Rennes, France ; Institut de Recherche Santé Environnement & Travail (IRSET), Institut National de la Santé et de la Recherche Médicale (INSERM), U1085, team 'Stress Membrane and Signaling', F-35043 Rennes, France.
Background:
Early in life, cystic fibrosis (CF) patients are infected with microorganisms. The role of macrophages has largely been underestimated in literature, whereas the focus being mostly on neutrophils and epithelial cells. Macrophages may however play a significant role in the initiating stages of this disease, via an inability to act as a suppressor cell. Yet macrophage dysfunction may be the first step in cascade of events leading to chronic inflammation/infection in CF. Moreover, reports have suggested that CFTR contribute to altered inflammatory response in CF by modification of normal macrophage functions.
Objectives:
In order to highlight possible intrinsic macrophage defects due to impaired CFTR, we have studied inflammatory cytokines secretions, recognition of pathogens and phagocytosis in peripheral blood monocyte-derived macrophages from stable adult CF patients and healthy subjects (non-CF).
Results:
In CF macrophage supernatants, concentrations of sCD14, IL-1β, IL-6, TNF-α and IL-10 were strongly raised. Furthermore expression of CD11b and TLR-5 were sorely decreased on CF macrophages. Beside, no difference was observed for mCD14, CD16, CD64, TLR-4 and TLR1/TLR-2 expressions. Moreover, a strong inhibition of phagocytosis was observed for CF macrophages. Elsewhere CFTR inhibition in non-CF macrophages also led to alterations of phagocytosis function as well as CD11b expression.
Conclusions:
Altogether, these findings demonstrate excessive inflammation in CF macrophages, characterized by overproduction of sCD14 and inflammatory cytokines, with decreased expression of CD11b and TLR-5, and impaired phagocytosis. This leads to altered clearance of pathogens and non-resolution of infection by CF macrophages, thereby inducing an exaggerated pro-inflammatory response.
Insights
Cystic fibrosis (CF) macrophages exhibit excessive inflammation, overproducing cytokines and showing impaired pathogen clearance due to CFTR defects. This dysfunction contributes to chronic infection and inflammation in CF patients.
Area of Science:
- Immunology
- Cell Biology
- Respiratory Medicine
Background:
- Cystic Fibrosis (CF) patients experience early microbial infections, with macrophages potentially playing a key role in disease initiation.
- Macrophage dysfunction, possibly linked to CFTR mutations, may precede chronic inflammation and infection in CF.
- Existing research often overlooks the role of macrophages, focusing more on neutrophils and epithelial cells.
Purpose of the Study:
- To investigate intrinsic macrophage defects in CF patients related to impaired Cystic Fibrosis Transmembrane conductance Regulator (CFTR) function.
- To compare inflammatory cytokine secretion, pathogen recognition, and phagocytosis in macrophages from CF patients versus healthy controls.
Main Methods:
- Studied peripheral blood monocyte-derived macrophages from stable adult CF patients and non-CF healthy subjects.
- Assessed inflammatory cytokine levels (sCD14, IL-1β, IL-6, TNF-α, IL-10) in macrophage supernatants.
- Measured cell surface marker expression (CD11b, TLR-5, mCD14, CD16, CD64, TLR-4, TLR1/TLR-2) and phagocytic activity.
Main Results:
- CF macrophages showed significantly elevated levels of sCD14 and inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-10).
- Decreased expression of CD11b and TLR-5 was observed on CF macrophages, while other markers remained unchanged.
- CF macrophages exhibited impaired phagocytosis, a defect also replicated by inhibiting CFTR in non-CF macrophages.
Conclusions:
- CF macrophages display excessive inflammation, characterized by cytokine overproduction and reduced CD11b/TLR-5 expression.
- Impaired phagocytosis and pathogen clearance by CF macrophages contribute to non-resolution of infection and exaggerated inflammation.
- These findings highlight macrophage dysfunction as a critical factor in the inflammatory cycle of cystic fibrosis.
Related Concept Videos
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation,...
Inflammatory Bowel Disease III: Crohn's Disease
Cystic Fibrosis: Management
Sinus disease and chronic...
Chronic Inflammation: Introduction
Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Inflammation
Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features


