Neutrophils From Aged Individuals Release NETs to Impair Oral Wound Healing Through NLRP3 Activation

This study aimed to investigate the mechanisms underlying impaired oral wound healing in aged individuals, with a focus on the roles of neutrophil extracellular traps (NETs) and NLRP3 inflammasome activation.

Palatal wound healing was compared between young and aged mice. We assessed the change of neutrophil infiltration, NETs formation, and NLRP3 inflammasome activation in mucosa using immunohistochemistry, RNA sequencing, and flow cytometry. In vitro co-culture assays evaluated NETs' effects on fibroblast function and NLRP3 inflammasome activation. The therapeutic potential of NETs-NLRP3 clearance was tested in vivo with DNase1 and MCC950. To validate clinical relevance, human single-cell RNA sequencing data were further analyzed.

Aged mice exhibited delayed oral wound healing, characterized by increased neutrophil recruitment and a heightened propensity for fibrin-induced NETs formation. NETs activated the NLRP3 inflammasome in mucosal fibroblasts, suppressing their proliferation and migration. Notably, targeting NETs-NLRP3 inflammasome reduced inflammation and accelerated wound closure in the aged group. Corresponding human data further revealed increased NETs-associated neutrophil subsets and enriched NLRP3 pathways in aged oral mucosa.

Our findings demonstrate that enhanced NETs formation and subsequent NLRP3 inflammasome impair wound healing in aged oral mucosa. Targeting NETs-NLRP3 thus represents a promising therapeutic strategy to improve mucosal repair.