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.

为了制定有效的镰状细胞病治疗策略，清楚地了解 需要细胞病理生理学。进入循环后，镰状细胞经历了许多变化和选择过程，从而深刻影响其对镰刀的倾向 及其生存特征。该建议的重点是理解这些时间依赖的变化。体内研究将跟踪少量高度纯化的光或致密 循环中的镰状细胞，利用生物素标记。这种方法是我们实验室所提供的 体内细胞老化过程中多个细胞特性的细胞分析。其中之一 特性，水合状态已被认为至关重要。现在 似乎一个方向脱水模型不足，镰状细胞 最终被补水并具有高钠含量，也许是严重的 膜损伤。初步的生物素标签研究表明，这些钠 负载的细胞的体内存活非常短。与他们的数字一起在 循环，这些数据强烈支持这些细胞作为末端细胞的重要作用 状态。拟议的研究将包括检查形成机制和 这些较旧的水合细胞的存活特征。镰状细胞的机械模型 基于对运输抑制剂DIDS和bumetanide的初步研究的补液， 将在拟议的研究中进行测试。相关的实验将检查磷脂酰丝氨酸（PS）外部化的高水平的初步研究表明，在体外恢复水中的镰状细胞中证明了这一点。体内和体外研究将评估非常年轻的红斑细胞（镰状和非咬伤）中存在的低水平PS暴露，以及随着镰刀细胞的年龄增长并脱水而形成的高水平暴露。 SC和CC疾病的患者为纯合镰状细胞疾病提供了重要且内容丰富的对立面。 SC和CC细胞的脱水动力学和生存特性将使用已建立的新开发的实验方法探索。这将允许与SS细胞的类似研究进行比较，并可以更好地理解这些疾病的脱水机制的相似性和差异。