TY - JOUR

T1 - Thrombin inhibits the anti-myeloperoxidase and ferroxidase functions of ceruloplasmin: relevance in rheumatoid arthritis

AU - Sokolov, A.V.

AU - Acquasaliente, L.

AU - Kostevich, V.A.

AU - Frasson, R.

AU - Zakharova, E.T.

AU - Pontarollo, G.

AU - Vasilyev, V.B.

AU - De Filippis, V.

PY - 2015

Y1 - 2015

N2 - Human ceruloplasmin (CP) is a multifunctional copper-binding protein produced in the liver. CP oxidizes Fe2+ to Fe3+, decreasing the concentration of Fe2+ available for generating harmful oxidant species. CP is also a potent inhibitor of leukocyte myeloperoxidase (MPO) (Kd=130nM), a major source of oxidants in vivo. Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting flexible joints and characterized by activation of both inflammatory and coagulation processes. Indeed, the levels of CP, MPO, and thrombin are markedly increased in the synovial fluid of RA patients. Here we show that thrombin cleaves CP in vitro at 481Arg-Ser482 and 887Lys-Val888 bonds, generating a nicked species that retains the native-like fold and the ferroxidase activity of the intact protein, whereas the MPO inhibitory function of CP is abrogated. Analysis of the synovial fluid of 24 RA patients reveals that CP is proteolytically degraded to a variable extent, with a fragmentation pattern similar to that observed wit

AB - Human ceruloplasmin (CP) is a multifunctional copper-binding protein produced in the liver. CP oxidizes Fe2+ to Fe3+, decreasing the concentration of Fe2+ available for generating harmful oxidant species. CP is also a potent inhibitor of leukocyte myeloperoxidase (MPO) (Kd=130nM), a major source of oxidants in vivo. Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting flexible joints and characterized by activation of both inflammatory and coagulation processes. Indeed, the levels of CP, MPO, and thrombin are markedly increased in the synovial fluid of RA patients. Here we show that thrombin cleaves CP in vitro at 481Arg-Ser482 and 887Lys-Val888 bonds, generating a nicked species that retains the native-like fold and the ferroxidase activity of the intact protein, whereas the MPO inhibitory function of CP is abrogated. Analysis of the synovial fluid of 24 RA patients reveals that CP is proteolytically degraded to a variable extent, with a fragmentation pattern similar to that observed wit

KW - Ceruloplasmin

KW - Myeloperoxidase

KW - Oxidants

KW - Protein–protein interaction

KW - Proteolysis

KW - Rheumatoid arthritis

KW - Surface plasmon resonance

KW - Thrombin

U2 - 10.1016/j.freeradbiomed.2015.05.016

DO - 10.1016/j.freeradbiomed.2015.05.016

M3 - Article

VL - 86

SP - 279

EP - 294

JO - Free Radical Biology and Medicine

JF - Free Radical Biology and Medicine

SN - 0891-5849

ER -