MEMBRANE PROTEIN DEFICIENCY OF PNH ERYTHROCYTES

PNH 红细胞膜蛋白缺乏症

• 批准号: 3345937
• 负责人: ANNE NICHOLSON-WELLER
• 金额: $ 30.06万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1994-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3345937
• 关键词: binding proteins; calcium transporting ATPase; complement; complement fixation tests; complement pathway; complement receptor; crosslink; enzyme inhibitors; erythrocyte membrane; erythrocytes; flow cytometry; gel electrophoresis; hemolysis; human subject; immunofluorescence technique; immunoprecipitation; laboratory rabbit; membrane permeability; membrane proteins; membrane structure; monoclonal antibody; paroxysmal nocturnal hemoglobinuria; surface antigens

Complement is a circulating system composed of many different proteins which is known for its ability to lyse animal cells and bacteria. This application seeks support for a series of investigations on the effects of complement on that do not lead to lysis of the target cell: the sublytic events. This proposal stems from our observation that when complement is activated at sublytical concentrations, influx of Na and L-glucose into the unlysed erthrocytes increases dramatically, albeit transiently, and yet the affected cells do not lyse or swell, as would be expected. We found that this non-lethal permeability increase is produced by the membrane attack complex, which is a macromolecular complex of the terminal complement components. Further we determined that C8, but not C9, is necessary to produce the sublytic change in permeability and that in response to the sublytic complement attack, there is activation of a Ca-dependent K permeability pathway. This promotes net K efflux and prevents the colloidosmotic swelling and lysis that occurs when the membrane damage is permanent and permits the survival of the affected cell. In PNH, a disease characterized by a dramatic increase in the sensitivity of erythrocytes to complement lysis, there is apparently a lack of sublytic changes for reasons not yet completely understood. Our specific aims include: 1) continue our studies on the complement regulatory proteins DAF and C8bp, particularly in relation to their role in the sublytic events; 2) characterize further the transient permeability changes and the volume regulatory transport mechanism through studies on ion fluxes during exposure to sublytic complement; and 3) determine the biological consequences of the sublytic events to the cells that survive a complement attack. We will perform studies in normal and PNH erthrocytes, as well as in cells carrying abnormal hemoglobin, such as SS, SC, or CC which are known to have volume regulatory pathways that we predict would decrease their sensitivity to complement lysis. We expect that our investigations will help better understanding complement mediated diseases, such as lupus erythematous and immune hemolytic anemia, and also provide important information on the physiological functions of the complement system and its regulatory proteins.

补体是一个循环系统， 蛋白质，已知其能够裂解动物细胞， 细菌 本申请寻求对一系列 关于补体对不导致 靶细胞的裂解：亚裂解事件。 这项建议 源于我们的观察，当补体被激活， 亚溶浓度，Na和L-葡萄糖流入 未裂解的红细胞急剧增加，尽管是短暂的， 但受影响的细胞不会如预期的那样溶解或膨胀。 我们发现，这种非致命的渗透性增加是由 膜攻击复合物是一种大分子复合物， 末端互补成分。 此外，我们确定C8， 而不是C9，是产生亚溶解性变化所必需的。 渗透性和对亚溶补体的反应 攻击，有激活钙依赖性钾渗透性 通路 这促进了钾的净流出， 当细胞膜 损伤是永久性的，并允许受影响的细胞存活。 在PNH中，这种疾病的特征是 红细胞对补体溶解的敏感性， 显然缺乏亚溶变化的原因还没有 完全理解 我们的具体目标包括：1）继续我们的 补体调节蛋白C8 bp和C8 bp的研究， 特别是与它们在次裂解事件中的作用有关; 2） 进一步表征瞬时渗透率变化， 通过离子通量研究体积调节运输机制 在暴露于亚溶解补体期间;和3）确定 亚溶解事件对细胞的生物学后果， 在补体攻击中幸存下来 我们将在正常和 PNH红细胞，以及携带异常血红蛋白的细胞， 例如已知具有音量调节功能SS、SC或CC 我们预测会降低他们对 补体溶解。 我们希望我们的调查能帮助 更好地了解补体介导的疾病，如狼疮 溶血性和免疫性溶血性贫血， 重要信息的生理功能的 补体系统及其调节蛋白。