Microvesicles Derived from Human Bronchial Epithelial Cells Regulate Macrophage Activation During Mycobacterium...

Area of Science:

• Immunology
• Cell Biology
• Microbiology

Background:

• Intercellular communication is crucial for host immunity against bacterial infections.
• Nontuberculous mycobacteria (NTM), like Mycobacterium abscessus (M. ab), cause severe lung infections, particularly in cystic fibrosis (CF) and COPD patients.
• Understanding host-pathogen interactions at the cellular level during NTM infection is limited.

Purpose of the Study:

• To characterize microvesicles (MVs) released by M. ab-infected human bronchial epithelial cells.
• To investigate the impact of these MVs on macrophage activation and polarization.
• To elucidate the role of MVs in host immune response to M. ab infection.

Main Methods:

• Isolation and characterization of microvesicles from M. ab-infected and uninfected human bronchial epithelial cells.
• Assessment of MV effects on THP-1-derived macrophage activation and polarization in cell culture.
• Proteomic analysis of isolated MVs to identify enriched proteins and pathways.

Main Results:

• MVs from M. ab-infected cells promoted M2 macrophage activation compared to MVs from uninfected cells.
• Proteomic analysis revealed enrichment of cell adhesion pathway proteins in MVs from infected cells.
• Intercellular adhesion molecule 1 (ICAM-1) on MVs regulated their uptake by macrophages.

Conclusions:

• Human airway epithelial cells release MVs in response to M. ab infection.
• These MVs modulate macrophage activation, influencing the host's immune response.
• The findings suggest a novel mechanism by which airway epithelial cells communicate with immune cells during NTM infections.