In Vivo Hydration Changes in Hemoglobin SS and SC Cells

血红蛋白 SS 和 SC 细胞的体内水合变化

• 批准号: 6782218
• 负责人: Clinton H Joiner
• 金额: $ 22.07万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-11 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6782218
• 关键词: age difference; biotin; cell age; cell morphology; cell water; clinical research; cooperative study; erythrocytes; hemoglobin Ss; human subject; ion transport; phosphatidylserines; sickle cell anemia

To develop effective treatment strategies for sickle cell disease, a clear understanding of cellular pathophysiology is required. After entering the circulation, sickle cells experience a number of changes and selection processes that profoundly influence their propensity to sickle and their survival characteristics. This proposal is focused on understanding these time-dependent changes. In vivo studies will track a small volume of highly purified light or dense sickle cells in the circulation, utilizing a biotin label. This method, unique to our laboratory, offers a cell-by-cell analysis of multiple cellular properties during in vivo cell aging. One of these properties, hydration state, has been recognized to be of paramount importance. It now appears that a one-directional dehydration model is not adequate, and that sickle cells eventually become rehydrated and have high sodium content, perhaps secondary to severe membrane damage. A preliminary biotin label study has demonstrated that these sodium loaded cells have an extremely short in vivo survival. Taken together with their numbers in the circulation, these data strongly support an important role for these cells as a terminal cellular state. The proposed studies will include examinations of the mechanism of formation and survival characteristics of these older, hydrated cells. A mechanistic model of sickle cell rehydration, based on preliminary studies with the transport inhibitors DIDS and bumetanide, will be tested in the proposed studies. Related experiments will examine the remarkably high level of phosphatidylserine (PS) externalization that preliminary studies demonstrated in sickle cells that were rehydrated in vitro. In vivo and in vitro studies will evaluate both the low level PS exposure that is present in very young erythroid cells, both sickle and nonsickle, and the high level exposure that appears to develop as sickle cells age and become dehydrated. Patients with SC and CC disease offer an important and informative counterpoint to homozygous sickle cell disease. The dehydration kinetics and survival characteristics of SC and CC cells will be explored using established and newly developed experimental approaches. This will allow a comparison to similar investigations with SS cells, and lead to a better understanding of similarities and differences in the dehydration mechanisms for these diseases.

为了制定镰状细胞病的有效治疗策略，需要清楚地了解 需要细胞病理生理学。进入循环系统后，镰状细胞会经历许多变化和选择过程，深刻影响它们的镰状细胞倾向 以及他们的生存特点。该提案的重点是理解这些与时间相关的变化。体内研究将追踪少量的高度纯化的光或密集的光 循环中的镰状细胞，利用生物素标签。这种方法是我们实验室独有的，可提供 对体内细胞衰老过程中多种细胞特性的逐个细胞分析。其中之一 性质，水合状态，已被认为是最重要的。现在它 似乎单向脱水模型是不够的，并且镰状细胞 最终会发生再水化并具有高钠含量，可能继发于严重的 膜损伤。初步的生物素标签研究表明，这些钠 负载的细胞在体内的存活时间极短。与他们在 循环中，这些数据有力地支持了这些细胞作为终端细胞的重要作用 状态。拟议的研究将包括对形成机制和 这些较老的水合细胞的生存特征。镰状细胞的机制模型 补液，基于转运抑制剂 DIDS 和布美他尼的初步研究， 将在拟议的研究中进行测试。相关实验将检验初步研究在体外再水化的镰状细胞中所证实的非常高水平的磷脂酰丝氨酸（PS）外化。体内和体外研究将评估非常年轻的红系细胞（镰状细胞和非镰状细胞）中存在的低水平 PS 暴露，以及随着镰状细胞老化和脱水而出现的高水平暴露。 SC 和 CC 疾病患者为纯合镰状细胞病提供了重要且信息丰富的对照。将使用已建立的和新开发的实验方法来探索 SC 和 CC 细胞的脱水动力学和生存特征。这将有助于与 SS 细胞的类似研究进行比较，并更好地了解这些疾病脱水机制的相似性和差异。