Endothelial NF-κB Blockade Abrogates ANCA-Induced GN

Area of Science:

• Immunology
• Nephrology
• Molecular Biology

Background:

• ANCA-associated vasculitis (AAV) involves ANCA-activated neutrophils and endothelium, leading to necrotizing vasculitis.
• Necrotizing crescentic glomerulonephritis (NCGN) is a severe manifestation of AAV.
• The role of endothelial nuclear factor-kappa B (NF-κB) in NCGN pathogenesis is not fully understood.

Purpose of the Study:

• To test the hypothesis that endothelial NF-κB mediates NCGN and represents a specific treatment target in AAV.
• To investigate the mechanism of NF-κB activation in endothelial cells (ECs) by ANCA-stimulated neutrophils.

Main Methods:

• Reanalysis of kidney tissues from murine NCGN models to assess NF-κB activation and related molecules.
• In vitro co-culture experiments using human neutrophils and ECs to study ANCA-induced NF-κB activation.
• In vivo studies in a murine NCGN model using siRNA-loaded immunoliposomes to target endothelial NF-κB.
• Analysis of kidney biopsies from patients with AAV for glomerular endothelial NF-κB activation.

Main Results:

• NF-κB activation, particularly the p50/p65 heterodimer, was observed in affected kidneys of NCGN models and correlated with crescent formation.
• ANCA-stimulated neutrophils activated NF-κB in ECs, partly via tumor necrosis factor-alpha (TNF-α) release, increasing interleukin-8 production and neutrophil adhesion.
• Prophylactic downregulation of endothelial NF-κB using siRNA-loaded immunoliposomes significantly reduced NCGN severity and renal myeloid cell influx in mice.
• Increased glomerular endothelial NF-κB activation was detected in patients with AAV-related NCGN.

Conclusions:

• Endothelial NF-κB activation, induced by ANCA-stimulated neutrophils, plays a critical role in the pathogenesis of NCGN.
• Targeting endothelial NF-κB activation presents a promising therapeutic avenue for ANCA-associated vasculitis.
• The findings highlight a specific molecular pathway that can be targeted for treating AAV.