The mechanism of intravenous immunoglobulin (IVIG) in vascular endothelial injury in kawasaki disease based on neutrophil extracellular traps

Abstract

This study explores the role of Neutrophil extracellular traps (NETs) in kawasaki disease (KD)-induced vascular inflammatory injury and the protective effect and mechanism of IVIG on vascular endothelial damage. A total of 37 children diagnosed with KD and admitted to Dongguan maternal and Child Health Care Hospital between March 2020 and June 2022 were included in the study. The children were divided into different groups based on their treatment and the presence or absence of coronary artery damage: IVIG treatment group (KDIVIG group), subgroup with coronary artery damage (KDCAL group), and subgroup without coronary artery damage (KDNCAL group), and a Control group consisting of 9 children who underwent surgical treatment. Flow cytometry was used to detect the proportion of neutrophils and the number of NETs in peripheral blood. It was found that the proportion of neutrophils in the peripheral blood of the acute KD group significantly increased with the presence of NETs. RT-PCR and ELISA detection showed that the levels of inflammatory factors TNF-α, IL-6 and CitH3 were abnormally elevated in this acute KD group, and the CAL group exhibited higher proportions of neutrophils and NETs-related markers compared to the NCAL group, while the IVIG group had significantly decreased proportions of neutrophils. PMA culture of neutrophils induced an increase expression of NETs marker protein, the content of NETs cfDNA increased. NETs culture could promote the secretion of TNF-α, whereas IVIG cultured cells inhibited the secretion of TNF-α. Finally, HCAEC cells were cultured with different levels of TNF-α, and the function of HCAEC cells was assessed using CCK8, scratch assay and flow cytometry. The high expression of TNF-α in the NETs group inhibited the proliferation and migration of HUVEC cells and enhanced their apoptosis. In contrast, the IVIG culture group exhibited similar effects to the TNF-α monoclonal antibody, as it inhibited HUVEC cell apoptosis and improved their viability by reducing TNF-α expression. Total protein was extracted from the cells using nano-magnetic beads, and RT-PCR and western blot detection indicated that the increase of TNF-α expression could increase the phosphorylation of NF-κB and and the expression of MMP-9. However, when TNF-α was inhibited by IVIG and TNF-α monoclonal antibody culture, the activity of NF-κB/MMP-9 athway was decreased. Therefore, IVIG may inhibit the production of NETs in KD children, thereby reducing TNF-α/NF-NF-κB/MMP-9 mediated inflammatory response process and protecting the function of vascular endothelial cells.