Identification of Specific Joint-Inflammatogenic Cell-Free DNA Molecules From Synovial Fluids of Patients With Rheumatoid Arthritis

• Published in: Frontiers in immunology Vol. 11; p. 662
• Main Authors: Dong, Cong, Liu, Yu, Sun, Chengxin, Liang, Huiyi, Dai, Lie, Shen, Jun, Wei, Song, Guo, Shixin, Leong, Kam W., Chen, Yongming, Wei, Lai, Liu, Lixin
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 28.04.2020
• Subjects: Adult; Animals; Arthritis, Rheumatoid - blood; autoimmunity; Biomarkers - blood; Case-Control Studies; cell-free DNA; Cell-Free Nucleic Acids - blood; Cell-Free Nucleic Acids - genetics; Cell-Free Nucleic Acids - isolation & purification; Cell-Free Nucleic Acids - pharmacology; Cohort Studies; CpG Islands; CpG-motif; Disease Models, Animal; Female; Humans; Immunology; inflammation; Inflammation - chemically induced; Inflammation - immunology; Male; Mice; Mice, Inbred BALB C; Middle Aged; Monocytes - drug effects; Monocytes - immunology; Osteoarthritis - blood; rheumatoid arthritis; Synovial Fluid - chemistry; Synovial Fluid - immunology; Synoviocytes - drug effects; Synoviocytes - immunology; THP-1 Cells; cell-free DNA; CpG-motif; autoimmunity; inflammation; rheumatoid arthritis
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2020.00662

Elevated cell-free DNA (cfDNA) levels in the plasma and synovial fluid of rheumatoid arthritis (RA) patients are proposed to be pathologically relevant. However, direct evidence to support this perception is lacking, and molecular feature of the cfDNA molecules with assumed pathological function is not well characterized. Here, we confirm remarkably increased levels of total synovial fluid and plasma cfDNAs in a large cohort of patients with rheumatoid arthritis compared to the counterparts in osteoarthritis, and demonstrate the potent inflammatogenic effects of RA synovial fluid cfDNA on both human monocyte cell line and primary cells related to RA. Massively parallel sequencing identifies distinct molecular pattern of cfDNA in RA, as characterized by enriching CpG-motif containing sequences. Importantly, these identified CpG-motif-rich sequences are hypomethylated in RA patients and induce severe inflammatory responses both and . Our data demonstrate the pathological role of global and specific cfDNA molecules in RA, thereby identifying novel therapeutic target candidate and potential biomarker for RA.