CXCR2⁺ Neutrophils Drive Neutrophil Extracellular Traps Formation and Exacerbate Pulpitis in Rats: An In Vitro and...

Area of Science:

• Immunology
• Oral Biology
• Pathology

Background:

• Pulpitis involves complex immune responses, including neutrophil extracellular traps (NETs).
• The specific role and regulation of NETs in pulpitis pathogenesis remain incompletely understood.
• Identifying key cellular players and signaling pathways is crucial for therapeutic development.

Purpose of the Study:

• To characterize NETs and their regulatory mechanisms in pulpitis.
• To evaluate the therapeutic potential of targeting specific neutrophil subsets in pulpitis.
• To delineate immune heterogeneity and intercellular communication in inflamed dental pulp.

Main Methods:

• Transcriptomic analyses (microarray, single-cell RNA sequencing) of pulpitis datasets.
• In vitro assays using neutrophils, macrophages, and dental pulp cells to study NETs induction and function.
• In vivo studies in rat pulpitis models using CXCR2 inhibition (AZD5069) followed by histological and micro-CT analysis.

Main Results:

• Transcriptomic data revealed significant enrichment of NETs-related pathways in inflamed pulp.
• NETs were confirmed in inflamed tissues and impaired dental pulp cell osteogenesis in vitro.
• A distinct pro-inflammatory CXCR2+ neutrophil subset specialized in NETs release was identified.
• Macrophage-derived CXCL8-CXCR2 signaling was identified as a key driver of neutrophil recruitment and NETs formation.
• CXCR2 inhibition in vivo reduced neutrophil infiltration and NETs release, promoting reparative mineralization.

Conclusions:

• CXCR2+ neutrophils are a pro-inflammatory subset driving NETs release in pulpitis via macrophage signaling.
• Inhibition of CXCR2 effectively attenuates pulpitis inflammation and enhances dentine repair.
• CXCR2 represents a promising therapeutic target for immune modulation in pulpitis treatment.