Role of NOD1/NOD2 receptors in Fusobacterium nucleatum mediated NETosis

Area of Science:

• Immunology
• Microbiology
• Periodontology

Background:

• Polymorphonuclear neutrophils (PMNs) are crucial for combating infections using strategies like phagocytosis and neutrophil extracellular traps (NETs).
• The function of PMNs in periodontal disease is recognized, but the precise molecular mechanisms driving NET formation remain unclear.
• Fusobacterium nucleatum is a significant periodontal pathogen implicated in disease progression.

Purpose of the Study:

• To investigate the role of Fusobacterium nucleatum in inducing NET formation.
• To elucidate the specific molecular pathways, particularly the involvement of NOD1 and NOD2 receptors, in F. nucleatum-mediated NETosis.

Main Methods:

• Utilized Fusobacterium nucleatum to stimulate neutrophils and induce NETosis.
• Employed CRISPR/Cas9 gene editing to knock out NOD1 and NOD2 receptors in HL-60 cells.
• Administered NOD1 and NOD2 ligands and inhibitors to assess their impact on NET formation and downstream signaling molecules.

Main Results:

• F. nucleatum induced robust NETosis in a time-dependent manner, mediated by the upregulation of NOD1 and NOD2 receptors.
• CRISPR/Cas9 knockout of NOD1/NOD2 and the use of specific inhibitors confirmed their essential role in F. nucleatum-induced NET formation.
• NOD1 and NOD2 signaling inhibition led to decreased peptidylarginine deiminase 4 (PAD4) activity and altered levels of myeloperoxidase (MPO) and neutrophil elastase (NE).

Conclusions:

• NOD1 and NOD2 receptors play a critical role in mediating F. nucleatum-induced NETosis.
• This study establishes a novel molecular pathway linking NOD-like receptors to NETosis triggered by F. nucleatum, a key periodontal pathogen.
• The findings provide new insights into the innate immune response in periodontal disease.