Battinelli E, Willoughby S R, Foxall T, Valeri C R, Loscalzo J
Whitaker Cardiovascular Institute and Evans Department of Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14458-63. doi: 10.1073/pnas.241427398.
Although the growth factors that regulate megakaryocytopoiesis are well known, the molecular determinants of platelet formation from mature megakaryocytes remain poorly understood. Morphological changes in megakaryocytes associated with platelet formation and removal of senescent megakaryocytes are suggestive of an apoptotic process. Previously, we have established that nitric oxide (NO) can induce apoptosis in megakaryocytoid cell lines. To determine whether there is an association between NO-induced apoptosis and platelet production, we exposed Meg-01 cells to S-nitrosoglutathione (GSNO) with or without thrombopoeitin (TPO) pretreatment and used flow cytometry and electron microscopy to assess platelet-sized particle formation. Meg-01 cells treated with TPO alone produced few platelet-sized particles (<3% of total counts), whereas treatment with GSNO alone produced a significant percentage of platelet-sized particles (22 +/- 4% of total counts); when combined with TPO pretreatment, however, GSNO led to a marked increase in platelet-sized particle production (48 +/- 3% of total counts). Electron microscopy confirmed that Meg-01 cells treated with TPO and GSNO yielded platelet-sized particles with morphological features specific for platelet forms. The platelet-sized particle population appears to be functional, because addition of calcium, fibrinogen, and thrombin receptor-activating peptide led to aggregation. These results demonstrate that NO facilitates platelet production, thereby establishing the essential role of NO in megakaryocyte development and thrombopoiesis.
尽管调节巨核细胞生成的生长因子已为人熟知，但成熟巨核细胞形成血小板的分子决定因素仍知之甚少。与血小板形成及衰老巨核细胞清除相关的巨核细胞形态学变化提示存在凋亡过程。此前，我们已证实一氧化氮（NO）可诱导巨核样细胞系发生凋亡。为确定NO诱导的凋亡与血小板生成之间是否存在关联，我们将Meg-01细胞暴露于S-亚硝基谷胱甘肽（GSNO），有无血小板生成素（TPO）预处理，并用流式细胞术和电子显微镜评估血小板大小颗粒的形成。单独用TPO处理的Meg-01细胞产生的血小板大小颗粒很少（占总数的<3%），而单独用GSNO处理则产生了相当比例的血小板大小颗粒（占总数的22±4%）；然而，当与TPO预处理联合使用时，GSNO导致血小板大小颗粒的产生显著增加（占总数的48±3%）。电子显微镜证实，用TPO和GSNO处理的Meg-01细胞产生了具有血小板形态特征的血小板大小颗粒。血小板大小颗粒群体似乎具有功能，因为添加钙、纤维蛋白原和凝血酶受体激活肽会导致聚集。这些结果表明，NO促进血小板生成，从而确立了NO在巨核细胞发育和血小板生成中的重要作用。
