MEGAKARYOCYTE PROTEOGLYCANS AND HYPERCHOLESTEROLEMIA

本项目的目标是了解蛋白聚糖在 正常的巨核细胞和血小板发育， 高胆固醇血症 我们观察到，沿着脂质的变化， 代谢，（S35）硫酸盐掺入血小板的变化， 高胆固醇血症动物，表明合成的实质性变化 蛋白多糖和其他硫酸化蛋白在巨核细胞的 高胆固醇血症的动物 目前的建议将扩大这些 问题研究 (1)蛋白聚糖的合成和代谢将在 在从正常和高胆固醇血症患者中分离的巨核细胞中进行体外研究。 豚鼠 将细胞与（S35）硫酸盐一起孵育。 （H3）葡糖胺和（H3）亮氨酸以标记蛋白聚糖和透明质酸 酸 蛋白聚糖将被表征， 合成和各种分子的周转率将是 确定，硫酸化分子的亚细胞位置将被确定。 通过用可以释放标记的 分子选择性地从细胞的颗粒或表面。 高胆固醇血症血清对蛋白多糖合成的调节作用 在新鲜分离的巨核细胞和长期骨髓中进行研究 cultures. (2)巨核细胞蛋白多糖的合成及其与细胞凋亡的关系 血小板的蛋白多糖含量将在体内研究，使用 巨核细胞和血小板分离自正常和高胆固醇血症 豚鼠注射（S35）硫酸盐。 的时间过程 放射性标记掺入特定蛋白聚糖和其它硫酸化 将在巨核细胞和血小板中研究大分子， 5天，以提供关于是否 不同成熟阶段的巨核细胞合成不同类型的 硫酸化分子，以及模式是否改变， 高胆固醇血症 各种硫酸化的亚细胞定位 分子将在体内标记的巨核细胞和血小板中探测。 蛋白多糖在豚鼠血小板中的功能作用将是 评估。 (3)豚鼠蛋白多糖的质量分布 将测定正常和 高胆固醇血症的动物 (4)这些研究将扩展到分析 正常人和高胆固醇血症人血小板蛋白多糖的含量。 这项研究预计将确定的作用知之甚少 巨核细胞和血小板生物学和发育中的蛋白聚糖，以及 它们在患者血小板异常发展中的重要性 高胆固醇血症

The goal of this project is to understand the role of proteoglycans in normal megakaryocyte and platelet development and in disorders such as hypercholesterolemia. We have observed, along with changes in lipid metabolism, changes in (S35) sulfate incorporation into platelets of hypercholesterolemic animals which suggest substantial changes in synthesis of proteoglycans and other sulfated proteins in the megakaryocytes of the hypercholesterolemic animals. The current proposal will extend these studies. (1) Proteoglycan synthesis and metabolism will be studied in vitro in megakaryocytes isolated from normal and hypercholesterolemic guinea pigs. The cells will be incubated with (S35) sulfate. (H3)glucosamine and (H3)leucine to label the proteoglycans and hyaluronic acid. The proteoglycans will be characterized, the time course of synthesis and the turnover rates of the various molecules will be determined, and the subcellular locations of the sulfated molecules will be assessed by treating the cells with agents which may release labeled molecules selectively from either the granules or surface of the cells. The regulation of proteoglycan synthesis by hypercholesterolemic serum will be studied both in freshly-isolated megakaryocytes and in long-term marrow cultures. (2) Proteoglycan synthesis in megakaryocytes and the proteoglycan content of platelets will be studied in vivo, using megakaryocytes and platelets isolated from normal and hypercholesterolemic guinea pigs which have been injected with (S35)sulfate. The time course of incorporation of radiolabel into specific proteoglycans and other sulfated macromolecules will be studied in both megakaryocytes and platelets over a period of five days in order to provide information concerning whether megakaryocytes at different stages of maturation synthesize different types of sulfated molecules, and whether the pattern is changed in hypercholesterolemia. The subcellular localization of the various sulfated molecules will be probed in megakaryocytes and platelets labeled in vivo. The functional role of proteoglycans in guinea pig platelets will be assessed. (3) The mass distribution of proteoglycans of guinea pig blatelets and megakaryocytes will be determined for both normal and hypercholesterolemic animals. (4) The studies will be extended to analysis of proteoglycans of platelets from normal and hypercholesterolemic humans. This research is expected to define the poorly-understood role of proteoglycans in megakaryocyte and platelet biology and development, and their importance in the development of platelet abnormalities in patients with hypercholesterolemia.