摘要
目的:研究血管性血友病因子裂解酶(ADAMTS13)在无流体剪切力下裂解内皮细胞上特大血管性血友病因子(ULVWF)的分子机制,为探明血栓性血小板减少性紫癜(TTP)和其他血栓性疾病的发病机理提供理论依据。方法:通过免疫荧光显微镜观察ADAMTS13在无流体剪切力下裂解内皮细胞表面上ULVWF的情况,采用ELISA测定不同条件下培养基中VWF抗原量的变化。ELISA和Western blot分别测定有无流体剪切力或凝血因子VIII(FVIII)条件培养基中的VWF和蛋白水解片段的数量。多聚体分析评估ADAMTS13裂解内皮细胞上ULVWF的情况。将组胺刺激的人脐静脉内皮细胞(HUVEC)与ADAMTS13和各种N-和C-末端截断的突变体一起孵育,通过免疫荧光显微镜观察与细胞保持结合的ULVWF,ELISA测定内皮细胞释放出的ULVWF,确定降解内皮细胞上ULVWF所需的ADAMTS13结构域。结果:在无流体剪切力下,重组ADAMTS13和血浆ADAMTS13迅速降解了内皮细胞表面上新形成的ULVWF。ULVWF的蛋白水解过程依赖于培养时间、ADAMTS13浓度和剪切力。ADAMTS13介导的蛋白水解释放的VWF分布与组胺刺激下内皮细胞分泌的VWF分布非常相似,提示ULVWF在内皮细胞表面发生裂解。裂解内皮细胞上ULVWF需要ADAMTS13半胱氨酸富集区(Cys-rich,Cys R)结构域和间隔区结构域,但不需要ADAMTS13的7个TSP1重复序列(TSP12-8)和2个补体结合区(CUB)结构域。结论:内皮细胞上ULVWF聚合物在无流体剪切力下也对ADAMTS13的裂解敏感,这为ADAMTS13裂解内皮细胞结合的ULVWF的分子机制提供了新见解,并可能有助于理解TTP和其他血栓性疾病的发病机理。
Objective:To investigate the molecular mechanism of proteolytic cleavage of unusually large von Willebrand Factor(ULVWF)on endothelial cells by ADAMTS13(a disintegrin and metalloprotease with thrombospondin type 1 repeats-13)in the absence of fluid shear stress,so as to provide a theoretical basis for the pathogenesis of thrombotic thrombocytopenic purpura(TTP)and other thrombotic disorders.Methods:The ADAMTS13-mediated proteolysis of ULVWF on the surface of endothelial cells in the absence of fluid shear stress was observed through immunofluorescence microscopy.The variation in VWF antigen levels in the conditioned media were determined by ELISA assay.The levels of VWF and the proteolytic fragments released into the conditioned media were determined by ELISA assay and Western blot in the absence and presence of fluid shear stress or FVIII.The effect of ADAMTS13-mediated ULVWF cleavage on the normal distribution of plasma VWF multimers was evaluated by multimer analysis.Histamine stimulated human umbilical vein endothelial cells(HUVECs)were incubated with ADAMTS13 and various N-and C-terminally truncated mutants.Then the ULVWF that maintained binding to the cells were observed through immunofluorescence microscopy and the soluble ULVWF released from endothelial cells was determined by ELISA,so as to demonstrate the domains of ADAMTS13 required for proteolysis of ULVWF on endothelial cells.Results:The ULVWF strings on the endothelial cell surface were rapidly proteolyzed by recombinant and plasma ADAMTS13 in the absence of fluid shear stress.This proteolytic processing of ULVWF depended on incubation time and ADAMTS13 concentration,but not shear stress and FVIII.The distribution of VWF releaseded by ADAMTS13-mediated proteolysis was quite similar to that secreted by endothelial cells under histamine stimulation,suggesting the ULVWF cleavage occured at the cell surface.The proteolysis of the ULVWF on endothelial cells required the Cys-rich(CysR)and spacer domains,but not the TSP12-8 and CUB domains of ADAMTS13.Conclusion:The ULVWF polymers on endothelial cells are sensitive to ADAMTS13-mediated cleavage even in the absence of fluid shear stress.The findings provide novel insight into the molecular mechanism of ADAMTS13-mediated ULVWF cleavage at the cellular level and may contribute to understanding of the pathogenesis of TTP and other thrombotic disorders.
作者
赵善琛
李华
王萌
赵艺鸿
李先杰
金圣宇
ZHAO Shan-Chen;LI Hua;WANG Meng;ZHAO Yi-Hong;LI Xian-Jie;JIN Sheng-Yu(Department of Hematology,Yanbian University Hospital(Yanbian Hospital),Yanji 133000,Jilin Province,China;Department of Physical Examination,Yanbian University Hospital(Yanbian Hospital),Yanji 133000,Jilin Province,China;Central Lab,Yanbian University Hospital(Yanbian Hospital),Yanji 133000,Jilin Province,China)
出处
《中国实验血液学杂志》
CAS
CSCD
北大核心
2024年第2期532-540,共9页
Journal of Experimental Hematology
基金
国家自然科学基金(81660026,82060032)
吉林省教育厅“十三五”科学技术研究项目[吉教科合字(2016)273号]。
