Neutrophil extracellular traps in asthma and chronic obstructive pulmonary disease: pathogenic roles, and therapeutic opportunities.

Asthma and chronic obstructive pulmonary disease (COPD) are the most prevalent chronic inflammatory airway diseases and constitute a substantial global health burden. Neutrophils are key effector cells of the innate immune system, playing an important role in the pathogenesis of multiple respiratory diseases. Recently, increasing attention has focused on the formation of neutrophil extracellular traps (NETs) as an important mechanism in diverse disease contexts, including neutrophilic asthma and COPD. NETs are web-like structures composed of DNA and diverse granule proteins that can trap and neutralize pathogens and modulate inflammatory responses. However, NETs also contain several cytotoxic proteins that can cause tissue damage, impair microbial clearance and promote disease progression. In this review, we summarize the components of NETs, the molecular mechanisms underlying NET formation, the interplay between NETs and T cells, current findings on the role of NETs in asthma and COPD, and emerging NET-targeted therapeutic strategies. Finally, we highlight current knowledge gaps and discuss future research directions in the field of NETs in asthma and COPD.