Platelet CXCL4 mediates neutrophil extracellular traps formation in ANCA-associated vasculitis

Kotaro Matsumoto,Hidekata Yasuoka,Katsuya Suzuki,Tsutomu Takeuchi,Keiko Yoshimoto

doi:10.1038/s41598-020-80685-4

Kotaro Matsumoto, Hidekata Yasuoka + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-80685-4

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Journal: Scientific Reports	Publication Date: Jan 8, 2021
Citations: 33	License type: open-access

Affiliation: Keio University, Fujita Health University

Abstract

Neutrophils form neutrophil extracellular traps (NETs), which are involved in the pathogenesis of ANCA-associated vasculitis (AAV). Recent reports suggest that platelets stimulated via toll-like receptor (TLR) pathways can induce NETs formation. However, the mechanism underlying the involvement of platelets in NETs formation in AAV is unknown. We investigated the role of platelets in the pathogenesis of AAV. Platelets from AAV patients and healthy controls (HCs) were co-cultured with peripheral neutrophils, and NETs formation was visualized and quantified. The expression levels of TLRs on platelets were examined by flow cytometry. Platelets were treated with a TLR agonist, platelet-derived humoral factor, CXCL4 (platelet factor 4: PF4), and/or anti-CXCL4 antibody to investigate the effects of TLR–CXCL4 signaling on NETs formation. Platelets from AAV significantly upregulated NETs formation in vitro. Flow cytometric analysis revealed that the proportion of TLR9 positive platelets was significantly higher in AAV than HCs. CXCL4 released from TLR9 agonist-stimulated platelets was significantly enhanced in AAV, which subsequently increased NETs formation. Further, neutralizing anti-CXCL4 antibody significantly inhibited NETs formation enhanced by platelets from AAV. TLR9 signaling and CXCL4 release underlie the key role that platelets play in NETs formation in the pathogenesis of AAV.

Highlights

Neutrophils form neutrophil extracellular traps (NETs), which are involved in the pathogenesis of ANCA-associated vasculitis (AAV)
Level of NETs formation induced by platelet-rich plasma (PRP) from AAV patients was significantly higher than platelet-poor plasma (PPP) from AAV patients, and that induced by PPP from AAV patients was higher than PPP from healthy controls (HCs)
We showed that activation of platelets through toll-like receptor (TLR) signaling pathways contributes to NETs formation and the progression of AAV

Summary

Introduction

Neutrophils form neutrophil extracellular traps (NETs), which are involved in the pathogenesis of ANCA-associated vasculitis (AAV). TLR9 signaling and CXCL4 release underlie the key role that platelets play in NETs formation in the pathogenesis of AAV. While the pathogenesis of AAV remains unclear, several reports have shown that vascular endothelial dysfunction due to neutrophil extracellular traps (NETs) may be an important trigger in the disease process[9]. Given recent evidence that TLR signaling pathways may play an important role in the development of chronic inflammation in rheumatic diseases[25], we hypothesized that activation of neutrophils by TLR signaling-activated platelets may contribute to the acceleration of NETs formation in patients with AAV. We investigated the role of platelets in the pathogenesis of AAV, in NETs formation, and the involvement of TLR signaling

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