Thrombophilia Caused by Beta2-Glycoprotein I Deficiency: In Vitro Study of a Rare Mutation in APOH Gene

Abstract

This study aimed to explore the mechanism of a novel mutation (p.Lys38Glu) in apolipoprotein H (APOH) gene causing hereditary beta2-glycoprotein I (β2GPI) deficiency and thrombosis in a proband with thrombophilia. The plasma level of β2GPI was measured by ELISA and Western blotting, and anti-β2GPI antibody by ELISA. Lupus anticoagulant (LA) was assayed using the dilute Russell viper venom time. Deficiency of the major natural anticoagulants including protein C (PC), protein S (PS), antithrombin (AT) and thrombomodulin (TM) was excluded from the proband. A mutation analysis was performed by amplification and sequencing of the APOH gene. Wild type and mutant (c.112A>G) APOH expression plasmids were constructed and transfected into HEK293T cells. The results showed that the thrombin generation capacity of the proband was higher than that of the other family members. Missense mutation p.Lys38Glu in APOH gene and LA coexisted in the proband. The mutation led to β2GPI deficiency and thrombosis by impairing the protein production and inhibiting the platelet aggregation. It was concluded that the recurrent thrombosis of the proband is associated with the coexistence of p.Lys38Glu mutation in APOH gene and LA in plasma.

Keywords

beta2-glycoprotein I / lupus anticoagulant / mutation / apolipoprotein H / thrombophilia

References

[1] RaskobGE, AngchaisuksiriP, BlancoAN, et al.. Thrombosis: A major contributor to global disease burden. Arterioscler Thromb Vasc Biol, 2014, 34(11): 2363-2371

[2] The Lancet-Haematology. Thromboembolism: an under appreciated cause of death. Lancet Haematol, 2015,2(10):e393

[3] SeligsohnU, LubetskyA. Genetic susceptibility to venous thrombosis. N Engl J Med, 2001, 344(16): 1222-1231

[4] BezemerID, BareLA, DoggenCJ, et al.. Gene variants associated with deep vein thrombosis. JAMA, 2008, 299(11): 1306-1314

[5] CorralJ, Gonzalez-ConejeroR, SoriaJM, et al.. A nonsense polymorphism in the protein Z-dependent protease inhibitor increases the risk for venous thrombosis. Blood, 2006, 108(1): 177-183

[6] TangL, WangHF, LuX, et al.. Common genetic risk factors for venous thrombosis in the Chinese population. Am J Hum Genet, 2013, 92(2): 177-187

[7] TangL, LuX, YuJM, et al.. PROC c.574_576del polymorphism: a common genetic risk factor for venous thrombosis in the Chinese population. J Thromb Haemost, 2012, 10(10): 2019-2026

[8] LimW. Thrombotic risk in the antiphospholipid syndrome. Semin Thromb Hemost, 2014, 40(7): 741-746

[9] GiannakopoulosB, KrilisSA. The pathogenesis of the antiphospholipid syndrome. N Engl J Med, 2013, 368(11): 1033-1044

[10] WillemsGM, JanssenMP, PelsersMM, et al.. Role of divalency in the high-affinity binding of anticardiolipin antibody-beta 2-glycoprotein I complexes to lipid membranes. Biochemistry, 1996, 35(43): 13833-13842

[11] de GrootPG, MeijersJC. Beta(2)-glycoprotein I: evolution, structure and function. J Thromb Haemost, 2011, 9(7): 1275-1284

[12] HulsteinJJ, LentingP d, LaatB, et al.. Beta2-glycoprotein I inhibits von Willebrand factor dependent platelet adhesion and aggregation. Blood, 2007, 110(5): 1483-1491

[13] SchousboeI. Beta 2-glycoprotein I: a plasma inhibitor of the contact activation of the intrinsic blood coagulation pathway. Blood, 1985, 66(5): 1086-1091

[14] PozziN, AcquasalienteL, FrassonR, et al.. Beta2 -glycoprotein I binds to thrombin and selectively inhibits the enzyme procoagulant functions. J Thromb Haemost, 2013, 11(6): 1093-1102

[15] TaylorKA, WrightJR, VialC, et al.. Amplification of human platelet activation by surface pannexin-1 channels. J Thromb Haemost, 2014, 12(6): 987-998

[16] HeikalNM, MurphyKK, CristRA, et al.. Elevated factor IX activity is associated with an increased odds ratio for both arterial and venous thrombotic events. Am J Clin Pathol, 2013, 140(5): 680-685

[17] GrafLL, WelshCH, QamarZ, et al.. Activated protein C resistance assay detects thrombotic risk factors other than factor V Leiden. Am J Clin Pathol, 2003, 119(1): 52-60

[18] RosendaalFR. Recently discovered frequent cause of venous thrombosis: factor V Leiden, a mutated factor V, resistant against protein C inactivation. Ned Tijdschr Geneeskd, 1994, 138(39): 1944-1948

[19] MarcucciR, BrunelliT, GiustiB, et al.. The role of cysteine and homocysteine in venous and arterial thrombotic disease. Am J Clin Pathol, 2001, 116(1): 56-60

[20] BauerKA. The thrombophilias: well-defined risk factors with uncertain therapeutic implications. Ann Intern Med, 2001, 135(5): 367-373

[21] PelkmansL, KelchtermansH, de GrootPG, et al.. Variability in exposure of epitope G40-R43 of domain i in commercial anti-beta2-glycoprotein I IgG ELISAs. PLoS One, 2013, 8(8): e71402

[22] SternP, LevineN. Controlled localized heat therapy in cutaneous warts. Arch Dermatol, 1992, 128(7): 945-948

[23] AgarC, van OsGM, MorgelinM, et al.. Beta2-glycoprotein I can exist in 2 conformations: implications for our understanding of the antiphospholipid syndrome. Blood, 2010, 116(8): 1336-1343

[24] de LaatB, van BerkelM, UrbanusRT, et al.. Immune responses against domain I of beta(2)-glycoprotein I are driven by conformational changes: domain I of beta(2)-glycoprotein I harbors a cryptic immunogenic epitope. Arthritis Rheum, 2011, 63(12): 3960-3968

[25] PericleousC, Ruiz-LimonP, Romay-PenabadZ, et al.. Proof-of-concept study demonstrating the pathogenicity of affinity-purified IgG antibodies directed to domain I of beta2-glycoprotein I in a mouse model of anti-phospholipid antibody-induced thrombosis. Rheumatology (Oxford), 2015, 54(4): 722-727

[26] PelkmansL d, LaatB. Antibodies against domain I of beta2-glycoprotein I: the one and only. Lupus, 2012, 21(7): 769-772