Characterizing mechanisms of sickle cell crisis via dynamic optical assay

描述(由申请人提供)：镰状细胞病(SCD)，以纯合子形式被称为镰状细胞性贫血，每50名非洲裔美国人中就有1人患有衰弱、慢性、危急发作和预期寿命缩短。SCD是一种遗传性血液疾病，由β-珠蛋白基因的单点突变引起。镰状血红蛋白(HBS)在脱氧时具有独特的聚合性，引发红细胞(RBC)的镰状和脱水，导致血管闭塞和毛细血管和小血管的血流障碍。HBS体外聚合的生物化学已为人所熟知。然而，由于缺乏合适的测量方法和现实的模型，在红细胞内，由于缺乏合适的测量方法和现实的模型，人们对HBS聚合引起的细胞力学和黏附特性的潜在变化的机制知之甚少。在生物光子学(由麻省理工学院的Peter So领导)、生物力学和微流体学(由麻省理工学院的Dao明道领导)以及SCD治疗(由UPMC的Gregory Kato领导)方面，三个具有互补专长的研究团队将联手开发可在RBC镰刀过程中量化RBC生物力学的技术。虽然导致血管闭塞的因素很多，但红细胞生物力学已被认为起着关键作用。预测血管闭塞模型的发展将加深我们在系统水平上对SCD病因学的理解，从而开发出更有效的药物和治疗方法。为了实现这些目标，我们的团队将开发反射模式定量位相显微镜和三维耗散粒子动力学(DPD)多尺度模型。这些技术结合在一起，将使我们能够在精确控制氧合水平的微流控设备内的镰状过渡过程中，以前所未有的精度量化红细胞流变性。我们将进一步开发基于互补相位显微镜的光谱方法来量化HBS的氧化和聚合状态。同时测量红细胞形态和流变学的变化以及HBS生化状态的变化将使我们更好地了解细胞内分子水平的变化如何驱动红细胞生物力学，这是血管闭塞和SCD危象的关键因素。这一方法的力量将在初步研究中进行评估，以阐明羟基尿素和AES-103的治疗机制。羟基脲是FDA批准的唯一一种专门用于SCD的药物，而AES-103是一种正在开发的新药。这些研究将提供原理证据，证明该平台可用于筛选新的抗镰刀菌药物。UPMC镰状细胞疾病登记处将提供丰富的临床数据库来注释患者样本，这些样本将通过先进的红细胞生物力学分析进行分析。这将使临床特征与生物力学分析得出的潜在生物标志物具有初步的探索性统计相关性。

DESCRIPTION (provided by applicant): Sickle cell disease (SCD), known in the homozygous form as sickle cell anemia, affects 1 in 50 African Americans with debilitating, chronic, crisis episodes and reduced life expectancy. SCD is an inherited blood disorder caused by a single point mutation in the beta-globin gene. Sickle hemoglobin (HbS) has the unique property of polymerizing when deoxygenated, triggering red blood cell (RBC) sickling and dehydration, leading to vaso-occlusion and impaired blood flow in capillaries and small vessels. The biochemistry of HbS polymerization in vitro is well understood. However, inside RBC, the mechanism of underlying changes in cell mechanics and adhesion properties resulting from HbS polymerization is poorly understood due to a lack of appropriate measurement methods and realistic models. Three research teams with complementary expertise in bio-photonics (lead by Peter So, MIT), in biomechanics and microfluidics (lead by Ming Dao, MIT), and in SCD treatment (lead by Gregory Kato, UPMC) will join force to develop technologies that can quantify RBC biomechanics during RBC sickling. While there are many factors contributing to vaso-occlusion, RBC biomechanics is known to play a key role. The development of a predictive vaso-occlusion model will deepen our understanding of SCD etiology on a system level allowing the development of more effective drugs and treatments. Toward these goals, our team will develop reflection mode quantitative phase microscopy and a 3-D dissipative particle dynamics (DPD) multi-scale model. These technologies together will allow us to quantify RBC rheological properties with unprecedented accuracy during sickling transition inside microfluidic devices with precisely controlled oxygenation level. We will further develop complementary phase microscopy based spectroscopic methods to quantify HbS oxygenation and polymerization states. Simultaneous measurement of changes in RBC shape and rheology with changes in HbS biochemical states should allow us to better understand how intracellular molecular level variations drive RBC biomechanics, a key factor in vaso-occlusion and SCD crisis. The power of this approach will be evaluated in pilot studies to elucidate the therapeutic mechanisms of hydroxyurea, the only FDA approved drug specifically for SCD, and Aes -103, a new drug under development. These studies will develop proof of principle that this platform could be utilized in screening new anti-sickling drugs. The UPMC sickle cell disease registry will provide a rich clinical database to annotate the patient specimens that will be analyzed by advanced RBC biomechanics assays. This will allow preliminary exploratory statistical correlation of clinical characteristics to the potential biomarkers derived from the biomechanics assays.