title: High-mobility group box 1 potentiates antineutrophil cytoplasmic antibody-inducing neutrophil extracellular traps formation.
abstract: BACKGROUND
  Recent studies found that the circulating high-mobility group box 1 (HMGB1) levels could reflect the disease activity of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). HMGB1 could prime neutrophils by increasing ANCA antigens translocation for ANCA-mediated respiratory burst and degranulation. The current study aimed to investigate whether HMGB1 participates in ANCA-induced neutrophil extracellular traps (NETs) formation, which is one of the most important pathogenic aspects in the development of AAV.
  
  
  METHODS
  NETs were induced by treating neutrophils with HMGB1 and ANCA-positive IgG in vitro. NETs formation was assessed using immunofluorescence microscopy and fluorescence probe. Antagonist for relevant receptors Toll-like receptor (TLR)2, TLR4 and the receptor for advanced glycation end products (RAGE), as well as NADPH oxidase molecules were employed.
  
  
  RESULTS
  The percentage of NETs formation was significantly higher in neutrophils stimulated with HMGB1 plus ANCA-positive IgG than that in neutrophils incubated with HMGB1 or ANCA-positive IgG alone. Consistently, compared with the nonstimulated neutrophils, the cell-free DNA (cfDNA) concentration of NETs was significantly increased from 334.09 ± 46.89 ng/ml to 563.32 ± 122.07 ng/ml in the neutrophils incubated with HMGB1 plus MPO-ANCA-positive IgG (P < 0.001), and from 303.44 ± 37.14 ng/ml to 563.79 ± 145.94 ng/ml in the neutrophils incubated with HMGB1 plus PR3-ANCA-positive IgG (P < 0.001). The aforementioned effect was significantly attenuated by antagonist for relevant receptors TLR2, TLR4 and RAGE, as well as blocking NADPH oxidase.
  
  
  CONCLUSIONS
  HMGB1 can potentiate ANCA-inducing NETs formation and may be involved in the pathogenesis of AAV. HMGB1 exerts effects on NETs formation through interaction with TLR2, TLR4 and RAGE, and the process is NADPH oxidase dependent.
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. mayunhua2013@sina.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. mayunhua2013@sina.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. mayunhua2013@sina.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. mayunhua2013@sina.com.|Renal Division, Department of Medicine, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China. mayunhua2013@sina.com.
authors.forename: Yun-Hua
authors.initials: YH
authors.lastname: Ma
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. 610630733@qq.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. 610630733@qq.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. 610630733@qq.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. 610630733@qq.com.
authors.forename: Tian-Tian
authors.initials: TT
authors.lastname: Ma
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. wangchen8784@163.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. wangchen8784@163.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. wangchen8784@163.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. wangchen8784@163.com.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. hopewanghuan@sina.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. hopewanghuan@sina.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. hopewanghuan@sina.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. hopewanghuan@sina.com.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. dongyuanchang1988@163.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. dongyuanchang1988@163.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. dongyuanchang1988@163.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. dongyuanchang1988@163.com.
authors.forename: Dong-Yuan
authors.initials: DY
authors.lastname: Chang
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. chenmin74@sina.com.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. chenmin74@sina.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. chenmin74@sina.com.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. chenmin74@sina.com.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, 100034, China. mhzhao@bjmu.edu.cn.|Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China. mhzhao@bjmu.edu.cn.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, 100034, China. mhzhao@bjmu.edu.cn.|Peking-Tsinghua Center for Life Sciences, Beijing, 100034, China. mhzhao@bjmu.edu.cn.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
mesh_terms: D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000378:metabolism; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D065206:Extracellular Traps / Q000187:drug effects / Q000378:metabolism*; D024243:HMGB1 Protein / Q000494:pharmacology*; D006801:Humans; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D024243:HMGB1 Protein; C585491:HMGB1 protein, human