Impaired "outside-in" integrin αIIbβ3 signaling and thrombus stability in TSSC6-deficient mice
Impaired "outside-in" integrin αIIbβ3 signaling and thrombus stability in TSSC6-deficient mice
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DOI：
10.1182/blood-2006-02-004267
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发表时间：
2006-09-15
期刊：
影响因子：
20.3
通讯作者：
Jackson, Denise E.
中科院分区：
文献类型：
--
作者：
Goschnick, Matt W.;Lau, Lai-Man;Jackson, Denise E.
我们研究了造血特异性四跨膜蛋白超家族成员TSSC 6在野生型小鼠和TSSC 6缺陷小鼠血小板功能中的作用。TSSC 6在鼠血小板表面上表达，并通过凝血酶刺激上调，表明TSSC 6的细胞内库。免疫沉淀/蛋白质印迹研究揭示了在强去污剂条件下TSSC 6与整合素α（IIb）β（3）复合物的组成性物理缔合。通过尾部出血进行的止血的体内评价揭示了TSSC 6缺失小鼠中出血时间增加、失血量增加和尾部再出血的证据，表明止血不稳定。使用离体技术，我们发现TSSC 6缺陷型血小板在低剂量PAR-4下表现出凝块收缩、血小板聚集以及在正常整合素α（IIb）β（3）表达存在下胶原和血小板在纤维蛋白原上铺展的动力学受损。TSSC 6缺陷型血小板表现出正常的α颗粒分泌、正常的“由内而外”整合素α（IIb）β（3）信号传导（异硫氰酸荧光素[FITC]-纤维蛋白原和JON/A结合）以及正常的血小板在纤维蛋白原上的粘附。此外，我们表明血小板TSSC 6的缺乏会影响血管损伤后体内动脉血栓的二级稳定性。这些数据表明TSSC 6似乎调节血小板中的整合素α（IIb）β（3）“由外向内”信号传导事件，并且是体内动脉血栓稳定性所必需的。
We investigated the role of the hematopoietic-specific tetraspanin superfamily member, TSSC6, in platelet function using wild-type mice and TSSC6-deficient mice. TSSC6 is expressed on the surface of murine platelets and is up-regulated by thrombin stimulation, indicating an intracellular pool of TSSC6. Immunoprecipitation/Western blot studies reveal a constitutive physical association of TSSC6 with the integrin alpha(IIb)beta(3) complex under strong detergent conditions. In vivo evaluation of hemostasis by tail bleeding revealed increased bleeding time, volume of blood lost, and evidence of tail rebleeds in TSSC6 null mice, indicating unstable hemostasis. Using ex vivo techniques, we showed that TSSC6-deficient platelets exhibited impaired kinetics of clot retraction, platelet aggregation at lower doses of PAR-4, and collagen and platelet spreading on fibrinogen in the presence of normal integrin alpha(IIb)beta(3) expression. TSSC6-deficient platelets showed normal alpha granule secretion, normal "inside-out" integrin alpha(IIb)beta(3) signaling (fluorescein isothiocyanate [FITC]-fibrinogen and JON/A binding), and normal platelet adhesion on fibrinogen. Furthermore, we show that absence of platelet TSSC6 affects the secondary stability of arterial thrombi in vivo upon vascular injury. These data demonstrate that TSSC6 appears to regulate integrin alpha(IIb)beta(3) "outside-in" signaling events in platelets and is necessary for stability of arterial thrombi in vivo.