Fibrinogen beta-chain tyrosine nitration is a prothrombotic risk factor.
Elevated levels of circulating fibrinogen are associated with an increased risk of atherothrombotic diseases although a causative correlation between high levels of fibrinogen and cardiovascular complications has not been established. We hypothesized that a potential mechanism for an increased prothrombotic state is the post-translational modification of fibrinogen by tyrosine nitration. Mass spectrometry identified tyrosine residues 292 and 422 at the carboxyl terminus of the beta-chain as the principal sites of fibrinogen nitration in vivo. Immunoelectron microscopy confirmed the incorporation of nitrated fibrinogen molecules in fibrin fibers. The nitration of fibrinogen in vivo resulted in four distinct functional consequences: increased initial velocity of fibrin clot formation, altered fibrin clot architecture, increased fibrin clot stiffness, and reduced rate of clot lysis. The rate of fibrin clot formation and clot architecture was restored upon depletion of the tyrosine-nitrated fibrinogen molecules. An enhanced response to the knob "B" mimetic peptides Gly-His-Arg-Pro(am) and Ala-His-Arg-Pro(am) suggests that incorporation of nitrated fibrinogen molecules accelerates fibrin lateral aggregation. The data provide a novel biochemical risk factor that could explain epidemiological associations of oxidative stress and inflammation with thrombotic complications.
Parastatidis
Ioannis
I
Stokes Research Institute and Departments of Pediatrics and Pharmacology, Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Thomson
Leonor
L
Burke
Anne
A
Chernysh
Irina
I
Nagaswami
Chandrasekaran
C
Visser
Jetze
J
Stamer
Sheryl
S
Liebler
Daniel C
DC
Koliakos
George
G
Heijnen
Harry F G
HF
Fitzgerald
Garret A
GA
Weisel
John W
JW
Ischiropoulos
Harry
H
D000293:Adolescent; D000328:Adult; D005337:Fibrin / Q000737:chemistry; D005340:Fibrinogen / Q000737:chemistry*; D006801:Humans; D016253:Microscopy, Immunoelectron / Q000379:methods; D008875:Middle Aged; D009584:Nitrogen / Q000737:chemistry; D018384:Oxidative Stress; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D012307:Risk Factors; D013927:Thrombosis / Q000175:diagnosis / Q000378:metabolism*; D014443:Tyrosine / Q000737:chemistry*
C115499:BBeta fibrinogen; D014443:Tyrosine; D005337:Fibrin; D005340:Fibrinogen; D009584:Nitrogen