CD177+neutrophils promote endothelial senescence through extracellular traps in Behçet's Disease.

Abstract

To investigate CD177⁺PMN dysregulation on endothelial cells in Behçet's disease (BD), a chronic systemic vasculitis characterized by polymorphonuclear neutrophil (PMN) activation and endothelial dysfunction. We reanalyzed BD PMN RNA sequencing data and quantified CD177⁺PMN in BD peripheral (n=38) and vascular tissue. We then analyzed BD and HC CD177⁺PMN using RNA sequencing (n=7), measured neutrophil extracellular traps (NETs) production, which were used to stimulate vascular endothelial cells (VECs) for RNA sequencing analysis. Differentially expressed proteins in NETs were determined by Mass spectrometry. Senescence, senescence-associated secretory phenotype (SASP) and PMN chemotaxis of VECs treated with BD CD177⁺PMN-derived NETs were assessed. Transcriptome analysis revealed BD PMN overexpressed CD177. CD177⁺PMN subset was expanded in active and severe systemic BD and was accumulated in BD aortic walls. Enhanced NETosis and oxidative phosphorylation in BD CD177⁺PMN was noted in RNA sequencing, which was confirmed in both resting and activated BD CD177⁺PMN. BD CD177⁺PMN-derived NETs promoted senescence, SASP and PMN chemotaxis in VECs using RNA sequencing analysis, which were validated by upregulated IL-6, CXCL8, ICAM-1, p21, SA-β-gal and cell proliferation arrest. Mass spectrometry identified BD CD177⁺PMN-derived NETs contained more Histone 3.1 (H3.1). H3.1 induced senescence, SASP and PMN chemotaxis in VECs via TLR4 signaling, which was attenuated by senolytics. Increased CD177⁺PMN in BD patients promote senescence and SASP in VECs through secreting H3.1-enriched NETs, which recruit PMN and collectively contribute to vasculitis in BD.