Red Blood Cell Adhesion in Sickle Cell Disease

描述(申请人提供)：血管闭塞是镰状细胞病(SS-D)发病和死亡的主要原因。我们推测，镰刀状红细胞(RBC)与血管内皮细胞的黏附增强涉及镰刀状红细胞膜内的黏附分子，最终导致SS-D的微血管闭塞。然而，设计合理的治疗镰状细胞病的方法的能力取决于对镰状细胞病中主要的病理细胞相互作用的更全面的了解。因此，本项目的中心目标是进一步阐明红细胞黏附在SS-D微血管闭塞中的作用。因此，本项目的具体目的是：1)鉴定和鉴定镰状红细胞膜上的黏附表位；2)研究镰状红细胞黏附调节剂对转基因镰刀鼠血管闭塞演变的影响；3)检测转基因镰刀鼠脑血管微循环中的镰刀状红细胞黏附。我们将利用重组噬菌体展示技术开发单抗，以鉴定和鉴定镰状红细胞膜上的黏附表位。为了测试特定的黏附表位的贡献，我们将使用体外流动黏附试验，洗涤的红细胞在受控剪切力的条件下与纯化的黏附蛋白或培养的内皮细胞相互作用。我们还将使用仅表达镰状HB的转基因小鼠，在更复杂的SS-D体内模型中进一步研究RBC黏附在急性血管闭塞发展中的作用。最后，我们将使用SS-D的转基因小鼠模型来专门研究RBC与大脑独特的内皮细胞的黏附。我们预计，这些研究将导致鉴定镰刀状红细胞膜中的特定黏附成分，这种黏附成分可以增强镰状红细胞与包括脑血管内皮细胞在内的血管壁的黏附。这些研究还将对抑制镰状红细胞与血管壁的黏附，防止内皮损伤，从而防止SS-D体内血管阻塞的机制提供洞察力。因此，我们期望从这一提议中获得的信息将导致治疗SS-D血管闭塞的新的治疗方法。

DESCRIPTION (provided by applicant): Vaso-occlusion is the major cause of morbidity and mortality in sickle cell disease (SS-D). We hypothesize that enhanced adhesion of sickle red blood cells (RBCs) to the vascular endothelium involves adhesive molecules within the sickle RBC membrane, ultimately leading to microvascular occlusion in SS-D. However, the ability to design rational approaches to treat sickle cell disease is dependent upon a more complete understanding of the predominant pathologic cellular interactions operative in sickle cell disease. Therefore, the central goal of this project is to further elucidate role of RBC adhesion in microvascular occlusion in SS-D. Consequently, the specific aims for this project are to: 1) Identify and characterize adhesive epitopes within the sickle RBC membrane, 2) Investigate the effect of modulators of sickle RBC adhesion on the evolution of vaso-occlusion in transgenic Sickle Mice, and 3) Examine sickle RBC adhesion in the cerebrovascular microcirculation of transgenic Sickle Mice. We will use recombinant phage display technology to develop monoclonal antibodies to identify and characterize adhesive epitopes within the sickle RBC membrane. To test the contribution of specific adhesive epitopes, we will employ an in vitro flow adhesion assay where washed RBCs interact with purified adhesive proteins or cultured endothelial cells under conditions of controlled shear force. We will also use transgenic mice that exclusively express sickle Hb to further examine the role of RBC adhesion in the development of acute vaso-occlusion in the more complex setting of an in vivo model of SS-D. Finally, we will use this transgenic mouse model of SS-D to specifically address RBC adhesion to the unique endothelium of the brain. We anticipate that these studies will lead to the identification of specific adhesive components within the sickle RBC membrane that augment the adhesion of sickle RBCs to the vessel wall, including cerebrovascular endothelium. These studies will also provide insight as to mechanisms that will inhibit the adhesion of the sickle RBC to the vessel wall, prevent endothelial injury and, therefore, subsequent vascular obstruction in vivo in SS-D. Thus, we expect that information derived from this proposal will lead to new therapeutic approaches for the treatment of vaso-occlusion in SS-D.