CD73 & THROMBOMODULIN

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 CD73是一种糖基磷脂酰肌醇(GPI)连接的膜蛋白，催化AMP胞外去磷酸化为腺苷。血栓调节蛋白(Tm)是一种存在于内皮细胞表面的I型跨膜蛋白。它作为凝血酶调节剂，因为凝血酶的底物专一性一旦与TM结合就会发生转换。在这项研究中，我们提出CD73产生的腺苷调节TM的表达，而TM是CD73产生的腺苷信号通路的靶点。目的：1.探讨CD73调节内皮细胞TM表达的途径及其对TM功能的影响。2.研究CD73在TM调节中的作用及其对TM功能的影响。3.研究抗凝系统在CD73功能中的作用。 我们的初步结果表明，在体外和体内，腺苷受体激动剂都能上调TM的表达水平。CD73产生的腺苷在体外也能增加TM的表达。在这项建议中，我们将确定负责TM调节的腺苷受体亚型和下游效应因子。对TM功能的影响将表现为内皮细胞上蛋白C的激活。我们比较了正常情况下CD73-/-小鼠和野生型小鼠中TM的表达水平。这些比较将在炎症条件下进行。对TM功能的影响将通过测定炎症条件下野生型小鼠和CD73-/-小鼠血浆中APC水平来表征。抗凝系统对CD73功能的影响也将在几种实验设置下进行研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. CD73 is a glycosylphosphatidylinositol (GPI)-linked membrane protein that catalyzes the extracellular dephosphorylation of AMP to adenosine. Thrombomodulin (TM) is a type I transmembrane protein located on the surface of endothelial cells. It serves as a thrombin modulator, since thrombin's substrate specificity is switched once binding to TM. In this study, we proposed that CD73-generated adenosine regulates TM expression and TM is a target of the CD73-generated adenosine signaling pathway. The specific aims are: 1. To delineate the pathway of CD73 regulated TM expression and the impact on TM functions in cultured endothelial cells. 2. To study the role of CD73 on TM regulation and the impact on TM functions in mouse model. 3. To study the role of anti-coagulation system involved in CD73 functions. Our preliminary results indicated that TM expression levels were up-regulated by an adenosine receptor agonist in vitro and in vivo. CD73-generated adenosine also can increase TM expression in vitro. In this proposal, we will identify the adenosine receptor subtype responsible for TM regulation and the downstream effectors. The impact on TM functions will be characterized by protein C activation on endothelial cells. We have compared TM expression levels in CD73-/- mice to that in wild type mice under normal conditions. These comparisons will be carried out under inflammatory conditions. The impact on TM functions will be characterized by measuring APC level in plasma in wild type mice and CD73-/- mice under inflammatory conditions. The impact of anti-coagulation system on CD73 functions will also be studied under several experimental settings.