Passam Freda H, Lin Lin, Gopal Srila, Stopa Jack D, Bellido-Martin Lola, Huang Mingdong, Furie Barbara C, Furie Bruce
Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; St George Clinical School, University of New South Wales, Sydney, Australia; and Department of Medicine, Harvard Medical School, Boston, MA.
Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Department of Medicine, Harvard Medical School, Boston, MA.
Blood. 2015 Apr 2;125(14):2276-85. doi: 10.1182/blood-2013-12-547208. Epub 2015 Jan 26.
Protein disulfide isomerase (PDI) and endoplasmic reticulum protein 57 (ERp57) are emerging as important regulators of thrombus formation. Another thiol isomerase, endoplasmic reticulum protein 5 (ERp5), is involved in platelet activation. We show here the involvement of ERp5 in thrombus formation using the mouse laser-injury model of thrombosis and a specific antibody raised against recombinant ERp5. Anti-ERp5 antibody inhibited ERp5-dependent platelet and endothelial cell disulfide reductase activity in vitro. ERp5 release at the thrombus site was detected after infusion of Alexa Fluor 488-labeled anti-ERp5 antibody at 0.05 μg/g body weight, a dose that does not inhibit thrombus formation. Anti-ERp5 at 3 μg/g body weight inhibited laser-induced thrombus formation in vivo by causing a 70% decrease in the deposition of platelets and a 62% decrease in fibrin accumulation compared to infusion of control antibody (P < .01). ERp5 binds to β3 integrin with an equilibrium dissociation constant (KD) of 21 µM, measured by surface plasmon resonance. The cysteine residues in the ERp5 active sites are not required for binding to β3 integrin. These results provide evidence for a novel role of ERp5 in thrombus formation, a function that may be mediated through its association with αIIbβ3.
蛋白质二硫键异构酶（PDI）和内质网蛋白57（ERp57）正逐渐成为血栓形成的重要调节因子。另一种硫醇异构酶，内质网蛋白5（ERp5），参与血小板活化。我们在此利用小鼠激光损伤血栓形成模型和针对重组ERp5产生的特异性抗体，展示了ERp5在血栓形成中的作用。抗ERp5抗体在体外抑制了ERp5依赖的血小板和内皮细胞二硫键还原酶活性。在以0.05μg/g体重输注Alexa Fluor 488标记的抗ERp5抗体后，检测到血栓部位有ERp5释放，该剂量不抑制血栓形成。与输注对照抗体相比，3μg/g体重的抗ERp5在体内抑制激光诱导的血栓形成，使血小板沉积减少70%，纤维蛋白积累减少62%（P <.01）。通过表面等离子体共振测量，ERp5与β3整合素结合的平衡解离常数（KD）为21μM。ERp5活性位点中的半胱氨酸残基对于与β3整合素的结合并非必需。这些结果为ERp5在血栓形成中的新作用提供了证据，该功能可能通过其与αIIbβ3的结合来介导。
