CalDAG-GEFI deficiency protects mice in a novel model of FcγRIIA-mediated thrombosis and thrombocytopenia
CalDAG-GEFI deficiency protects mice in a novel model of FcγRIIA-mediated thrombosis and thrombocytopenia
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DOI：
10.1182/blood-2011-03-342352
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发表时间：
2011-07-28
期刊：
影响因子：
20.3
通讯作者：
Bergmeier, Wolfgang
中科院分区：
文献类型：
--
作者：
Stolla, Moritz;Stefanini, Lucia;Bergmeier, Wolfgang
通过Fc γ受体IIA（Fc γ RIIA）的血小板活化是免疫介导的血小板减少症和血栓形成综合征（ITT）中的关键事件。我们最近确定了鸟嘌呤核苷酸交换因子CalDAG-GEFI和二磷酸腺苷受体P2 Y12作为导致Rap 1小GT3活化和血小板聚集的独立途径的信号传导。在这里，我们评估了CalDAG-GEFI和P2 Y12信号传导对ITT中血小板活化的贡献。产生人Fc γ RIIA（hFcR）转基因且缺乏CalDAG-GEFI（-/-）（hFcR/CDGI（-/-））的小鼠。与对照相比，hFcR/CDGI（-/-）血小板或P2 Y12转运蛋白处理的hFcR血小板的聚集分别需要高出5倍和大约2倍浓度的Fc γ RIIA刺激性抗CD 9抗体。在P2 Y12转运蛋白处理的hFcR/CDGI（-/-）血小板中，聚集和Rap 1活化被消除。对于体内研究，建立了抗体诱导的血小板减少症和血栓形成的新模型。通过输注Alexa 750标记的糖蛋白IX（CD 42 a）抗体诱导Fc γ RIIA依赖性血小板血栓形成，并通过近红外成像技术检测肺血栓。抗GPIX抗体在hFcR转基因小鼠中剂量依赖性地引起血小板减少症和肺血栓形成，但在野生型小鼠中没有。CalDAG-GEFI缺陷型hFcR转基因小鼠完全免于ITT，但氯吡格雷处理的hFcR转基因小鼠没有。总之，我们建立了一种新的ITT小鼠模型，用于鉴定CalDAG-GEFI作为治疗ITT的潜在新靶点。（血。2011; 118（4）：1113-1120）
Platelet activation via Fc gamma receptor IIA (Fc gamma RIIA) is a critical event in immune-mediated thrombocytopenia and thrombosis syndromes (ITT). We recently identified signaling by the guanine nucleotide exchange factor CalDAG-GEFI and the adenosine diphosphate receptor P2Y12 as independent pathways leading to Rap1 small GTPase activation and platelet aggregation. Here, we evaluated the contribution of CalDAG-GEFI and P2Y12 signaling to platelet activation in ITT. Mice transgenic for the human Fc gamma RIIA (hFcR) and deficient in CalDAG-GEFI(-/-) (hFcR/CDGI(-/-)) were generated. Compared with controls, aggregation of hFcR/CDGI(-/-) platelets or P2Y12 inhibitor-treated hFcR platelets required more than 5-fold and approximately 2-fold higher concentrations of a Fc gamma RIIA stimulating antibody against CD9, respectively. Aggregation and Rap1 activation were abolished in P2Y12 inhibitor-treated hFcR/CDGI(-/-) platelets. For in vivo studies, a novel model for antibody-induced thrombocytopenia and thrombosis was established. Fc gamma RIIA-dependent platelet thrombosis was induced by infusion of Alexa750-labeled antibodies to glycoprotein IX (CD42a), and pulmonary thrombi were detected by near-infrared imaging technology. Anti-GPIX antibodies dose-dependently caused thrombocytopenia and pulmonary thrombosis in hFcR-transgenic but not wild-type mice. CalDAG-GEFI-deficient but not clopidogrel-treated hFcR-transgenic mice were completely protected from ITT. In summary, we established a novel mouse model for ITT, which was used to identify CalDAG-GEFI as a potential new target in the treatment of ITT. (Blood. 2011; 118(4):1113-1120)