Paris Center for Cardiovascular Research, INSERM UMR s-970, Hôpital Européen Georges Pompidou, et Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
Blood. 2012 Dec 13;120(25):5050-8. doi: 10.1182/blood-2012-02-413138. Epub 2012 Sep 13.
Patients with sickle cell disease suffer from painful crises associated with disseminated vaso-occlusions, increased circulating erythrocyte microparticles (MPs), and thrombospondin-1 (TSP1). MPs are submicron membrane vesicles shed by compromised or activated cells. We hypothesized that TSP1 mediates MP shedding and participates in vaso-occlusions. We injected TSP1 to transgenic SAD mice with sickle cell disease and characterized circulating phosphatidylserine+ MPs by FACS. TSP1 stimulated MPs in plasma and initiated vaso-occlusions within minutes. In vitro, TSP1 triggered rapid erythrocyte conversion into spicule-covered echinocytes, followed by MP shedding. MP shedding was recapitulated by peptides derived from the TSP1 carboxyterminus. We purified MPs shed by erythrocytes in vitro and administered them back to SAD mice. MPs triggered immediate renal vaso-occlusions. In vitro, MPs triggered the production of radical oxygen species by endothelial monolayers, favored erythrocyte adhesion, and induced endothelial apoptosis. MPs also compromised vasodilation in perfused microvessels. These effects were inhibited by saturating MP phosphatidylserine with annexin-V, or with inhibitors of endothelial ROS production. We conclude that TSP1 triggers erythrocyte MP shedding. These MPs induce endothelial injury and facilitate acute vaso-occlusive events in transgenic SAD mice. This work supports a novel concept that toxic erythrocyte MPs may connect sickle cell anemia to vascular disease.
患有镰状细胞病的患者会遭受与弥散性血管阻塞、循环中红细胞微颗粒（MPs）增加和血栓调节蛋白-1（TSP1）相关的疼痛危象。MPs 是由受损或激活的细胞释放的亚微米膜囊泡。我们假设 TSP1 介导 MPs 的脱落并参与血管阻塞。我们将 TSP1 注射到患有镰状细胞病的转基因 SAD 小鼠中，并通过 FACS 对循环中的磷脂酰丝氨酸+ MPs 进行了特征分析。TSP1 在几分钟内刺激了血浆中的 MPs 并引发了血管阻塞。在体外，TSP1 迅速引发红细胞转化为覆盖有刺的棘状红细胞，随后 MPs 脱落。TSP1 羧基末端衍生的肽可重现 MPs 的脱落。我们在体外纯化了由红细胞脱落的 MPs，并将其回输给 SAD 小鼠。MPs 可立即引发肾脏血管阻塞。在体外，MPs 可引发内皮单层产生自由基，有利于红细胞黏附，并诱导内皮细胞凋亡。MPs 还可损害灌注微血管的舒张。这些作用可通过用 annexin-V 或内皮细胞 ROS 产生抑制剂使 MPs 的磷脂酰丝氨酸饱和来抑制。我们得出结论，TSP1 可引发红细胞 MPs 的脱落。这些 MPs 可诱导内皮损伤，并促进转基因 SAD 小鼠的急性血管阻塞事件。这项工作支持了一个新的概念，即有毒的红细胞 MPs 可能将镰状细胞性贫血与血管疾病联系起来。
