K Otomo1, O Amengual1, Y Fujieda1, H Nakagawa1, M Kato1, K Oku1, T Horita1, S Yasuda1, M Matsumoto2, K I Nakayama2, S Hatakeyama3, T Koike4, T Atsumi5. 1. Division of Rheumatology, Endocrinology and Nephrology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. 2. Division of Proteomics, Multi-scale Research Center for Prevention of Medical Science, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan. 3. Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan. 4. Sapporo Medical Center NTT EC, Sapporo, Japan. 5. Division of Rheumatology, Endocrinology and Nephrology, Hokkaido University Graduate School of Medicine, Sapporo, Japan at3tat@med.hokudai.ac.jp.
Abstract
OBJECTIVE: The objective of this paper is to elucidate the not yet known plasma molecule candidates involved in the induction of tissue factor (TF) expression mediated by β2GPI-dependent anticardiolipin antibody (aCL/β2GPI) on monocytes. METHODS: Human serum incubated with FLAG-β2GPI was applied for affinity chromatography with anti- FLAG antibody. Immunopurified proteins were analyzed by a liquid chromatography coupled with mass spectrometry (LC-MS). TF mRNA induced by the identified molecules on monocytes was also analyzed. RESULTS: Apolipoprotein B100 (APOB) was the only identified serum molecule in the MS search. Oxidized LDL, containing APOB as well as ox-Lig1 (a known ligand of β2GPI), was revealed as a β2GPI-binding molecule in the immunoprecipitation assay. TF mRNA was markedly induced by oxidized LDL/β2GPI complexes with either WBCAL-1 (monoclonal aCL/β2GPI) or purified IgG from APS patients. The activities of lipoprotein-associated phospholipase A2, one of the component molecules of oxidized LDL, were significantly higher in serum from APS patients than in those from controls. CONCLUSION: APOB (or oxidized LDL) was detected as a major β2GPI binding serum molecule by LC-MS search. Oxidized LDL/aCL/β2GPI complexes significantly induced TF expressions on monocytes. These data suggest that complexes of oxidized LDL and aCL/β2GPI may have a crucial role in the pathophysiology of APS.
OBJECTIVE: The objective of this paper is to elucidate the not yet known plasma molecule candidates involved in the induction of tissue factor (TF) expression mediated by β2GPI-dependent anticardiolipin antibody (aCL/β2GPI) on monocytes. METHODS:Human serum incubated with FLAG-β2GPI was applied for affinity chromatography with anti- FLAG antibody. Immunopurified proteins were analyzed by a liquid chromatography coupled with mass spectrometry (LC-MS). TF mRNA induced by the identified molecules on monocytes was also analyzed. RESULTS:Apolipoprotein B100 (APOB) was the only identified serum molecule in the MS search. Oxidized LDL, containing APOB as well as ox-Lig1 (a known ligand of β2GPI), was revealed as a β2GPI-binding molecule in the immunoprecipitation assay. TF mRNA was markedly induced by oxidized LDL/β2GPI complexes with either WBCAL-1 (monoclonal aCL/β2GPI) or purified IgG from APSpatients. The activities of lipoprotein-associated phospholipase A2, one of the component molecules of oxidized LDL, were significantly higher in serum from APSpatients than in those from controls. CONCLUSION:APOB (or oxidized LDL) was detected as a major β2GPI binding serum molecule by LC-MS search. Oxidized LDL/aCL/β2GPI complexes significantly induced TF expressions on monocytes. These data suggest that complexes of oxidized LDL and aCL/β2GPI may have a crucial role in the pathophysiology of APS.