PAD4 Probably Play An Important Role In Rheumatoid Arthritis By Involving In The Formation Of The Neutrophil Extracellular Traps

Objective:To detect the levels of peripheral blood neutrophils PAD4 mRNA levels in neutrophils cells, the levels of neutrophil extracellular traps (NETs) in serum and the levels of histone H4R3 citrullination in PBMCs from rheumatoid arthritis(RA), investigate the associations between PAD4mRNA,H4R3 citrullination and NETs in RA, and explore its value in the pathogenesis of RA.Methods The serum dsDNA/NETs in 43 RA patients and 20 healthy controls were detected by PicoGreen dsDNA Quantitation Kits (Invitrogen),the levels of histone H4R3 were detected by Western blotting, and the expression of PAD4 mRNA in neutrophils were measured by Real-time PCR,and the relationship between dsDNA/NETs and their clinical indexes were analyzed.Results 1)The level of peripheral blood neutrophils PAD4 mRNA in RA was significantly higher than healthy controls([1.493(0.831,2.607)] vs [0.631(0.358,1.489)],P=0.039);The levels of serum PAD4mRNA in RA treated by DMARDs were lower than thatuntreated by DMARDs, but no significance e differencewere found (z=-1.19, p=0.234) 2)The levels of serum dsDNA/NETs in RA patients were significantly higher than in healthy controls([0.436(0.330,0.611) ug/ml vs[0.240(0.140,0.325) ug/ml], P<0.001),The levels of serum dsDNA/NETs in RA treated by DMARDs were lower than that untreated by DMARDs, but no significance difference were found ([0.423 (0.317,0.594) ug/ml] vs[0.433 (0.321,0.730) ug/ml],p=0.448). 3) The levels of histone H4R3 citrullination in RA was significantly higher than healthy controls [(0.731±.214)vs (0.547±0.204),P<0.001],The level of histone H4R3 citrullination in RA treated by DMARDs were lower than that untreated byDMARDs, but no significance difference were found[(0.683±0.220) vs (0.823±0.160),p=0.415] 4).The levels of serum dsDNA/NETs in RA was positively correlated with PAD4mRNA,DAS28 score,ESR and CRP (r=0.42,p=0.017;r=0.36, P=0.036; r=0.345, P=0.042; r=0.36, P=0.043)but not with anti-CCP antibodies, histone H4R3 citrullination, Disease duration, age (r=0.277, P=0.154; r=-0.275, p=0.157; r=0.286,p=0.096; r=-0.087, p=0.423);The levels of peripheral blood neutrophils PAD4 mRNA was not associated with H4R3 citrullination,ESR,CRP,DAS28 score anti-CCP antibodies,. Disease duration, age (r=0.181, p=0.553; r-0.256, p=0.239; r=0.239, p=0.284; r=0.341, p=0.111; r=0.170, p=0,515; r=0.238, p=0.273; r=0.099, p=0.529);The level of histone H4R3 citrullination was not associated with ESR,CRP,DAS28,Disease duration,age (r=-0.169, p=0.390; r=-0.149, p=0.582; r=-0.135, p=0.493; r=-0.256, p=0.276; r=-0.004, p-0.985)Conclusion 1).PAD4 maybe play an important role in the pathogenesis of RA. 2).NETs maybe associated with disease activity and play an improtmant role in RA pathogensis, inhibit NETs generate or improve the ability to clear NETs perhaps can treatRA. 3)Histone H4R3 citrullination maybe play an important role in the pathogenesis of RA. 4)PAD4 probably play an importent role in rheumatoid arthritis by influence the formation of the NETs.