Effects Of Platelets On The Ability Of Von Willebrand Factor By ADAMTS13 Under Fluid Shear Stress

Objective:To study the auxiliary role of platelets in ADAMTS13 regulating multimeric v WF,to provide a theoretical basis for studying the pathogenesis and treatment of Thrombotic Thrombocytopenic Purpura(TTP).Methods:Recombinant ADAMTS13 was expressed by stably transfected HEK293 cells,and the protein concentration was determined by spectrophotometer after the expression product was purified by chromatography.Recombinant ADAMTS13 and histamine were incubated on coverslips covered with human umbilical vein endothelial cells(HUVECS),the fluid shear force model was used to simulate blood flow to provide shear force,and the v WF multimers secreted by HUVECS under various conditions were collected,and visualized by western blot.Statistical analysis was performed after the data of each group was analyzed by Image J.Results:1.Wild-type ADAMTS13 was stably expressed in HEK293 cells.2.Under the stimulation of histamine,Ultra Large von Willebrand Factor,UL-v WF secreted by HUVECS increased significantly compared with that without stimulation of histamine.3.The amount of UL-v WF secreted by HUVECS increased significantly under the action of fluid shear force compared with that under the action of no fluid shear force.4.The cleavage ability of ADAMTS13 to v WF multimer was significantly increased under the action of shear force in vitro(P<0.01).5.Platelets can synergistically enhance the lysis of UL-v WF released from HUVECs by ADAMTS13 under fluid shear stress(P<0.0001).Conclusion:1.The cleavage of v WF multimers by ADAMTS13 requires the action of fluid shear force.2.Platelets(PLT)can synergistically enhance the ability of ADAMTS13 to cleave v WF multimers under flow shear conditions.