Diverse stimuli engage different neutrophil extracellular trap pathways

Area of Science:

• Immunology
• Cell Biology

Background:

• Neutrophils release neutrophil extracellular traps (NETs) that play a role in pathogen ensnarement and disease pathogenesis.
• NETosis, the process of NET release, is crucial for host defense but can also be detrimental.

Purpose of the Study:

• To investigate the distinct signaling pathways involved in NETosis induced by different stimuli.
• To characterize the composition and functional activity of NETs produced via these pathways.

Main Methods:

• Stimulation of neutrophils from healthy donors and patients with genetic defects (CGD, MPO-deficiency) using PMA, calcium ionophore A23187, nigericin, Candida albicans, and Group B Streptococcus.
• Utilized inhibitors targeting key molecules in PMA-induced NETosis, including protein kinase C, calcium, reactive oxygen species, myeloperoxidase (MPO), and neutrophil elastase.

Main Results:

• PMA, Candida albicans, and Group B Streptococcus induced NETs via a related pathway.
• Calcium ionophores (A23187) required an alternative pathway for NET induction.
• NETs generated by all tested stimuli were proteolytically active, demonstrated bactericidal activity, and were primarily composed of chromosomal DNA.

Conclusions:

• NETosis can be initiated through multiple distinct signaling mechanisms.
• The extrusion of NETs is a vital component of the host immune defense against pathogens.