ENDOTHELIAL DYSFUNCTION AND VASOOCCLUSION IN SICKLE CELL ANEMIA

镰状细胞性贫血中的内皮功能障碍和血管闭塞

• 批准号: 6667525
• 负责人: VIJAY K. KALRA
• 金额: $ 49.81万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6667525
• 关键词: BCL2 gene /protein; blood vessel occlusion; cell adhesion; cell adhesion molecules; cellular pathology; clinical research; erythrocytes; gene expression; human subject; hypoxia; lipid peroxides; molecular cloning; nuclear factor kappa beta; nucleic acid probes; oxidative stress; peroxidation; phosphatidylserines; protein purification; receptor expression; selectins; sickle cell anemia; sickle cell crisis; tissue /cell culture; vascular endothelium; vasoactive agent

Vasoocclusive crisis is the major cause of morbidity and mortality in sickle cell disease (SCD). The molecular cascade giving rise to slowed blood-vessel flow remains elusive. Slowing of blood flow and hence oxygen delivery to tissues very likely relates to the adherence of sickle cell (SS) RBC to vascular endothelium, localized tissue hypoxia secondary to blood stasis and/or inflammation common in SCD. SS RBC adherence may affect blood flow by promoting, via surface expression of counter- receptors on the endothelium, the additional binding of SS RBC and leukocytes. We hypothesize that SS RBC adherence to endothelium generates cellular oxidant stress (evidenced by lipid peroxide formation and activation of transcription factor NF-kb), leading to a surface expression (SE) of a subset of cell adhesion molecules (CAMs), ICAM-1, E- selectin and BCAM-1. Similarly, infection/inflammation causes an increase in CAM expression. The induced SE of VCAM-1 leads to a greater adherence of less dense SS RBC through their alpha4beta1 ligand. The adherence and subsequent diapedesis of PMN and monocytes occurs via the increased SE of CAMs, which act as counter-receptors for integrins on these cells. Because the activation of NF-kB occurs partly through lipid peroxides generated by oxidant stresses such as vasoocclusion, e plan to determine whether overexpression of bcl-2 (a lipid peroxide-suppressing protooncogene) in cultured human umbilical vein endothelial cells (HUVEC) will prevent lipid peroxidation, NF-Kb activation and a CAM induction when transfected HUVEC are incubated with SS RBC. Dense deoxygenated SS RBC display phosphatidylserine (PS) on the external leaflet of the RBC bilayer and adhere to HUVEC through the PS receptor, so we will determine whether LPS and cytokines, which induce the expression of PS receptor, potentiate dense deoxygenated SS RBC adherence. Additionally, hypoxia increases monocyte trans endothelial migration, which may contribute to vasoocclusion; thus we propose investigating the mechanism of hypoxia-induced diapedesis of PMN and monocytes. We will also examine the mechanism(s) by which SS RBC, LPS and cytokine interaction with HUVEC alters CAM expression, the concomitant adherence of PMN and monocytes, and the augmented SS RBC adherence. Moreover, we will investigate CAM induction in endothelial cells derived from distinct vascular beds (pulmonary microvessel, pulmonary artery and brain), and potential differences in such induction effected by various shear stresses, mimicking conditions prevalent in various vascular beds. These completed studies will provide insight into new pharmacological and/or molecular approaches to ameliorate the clinical manifestations of vasoocclusion in sickle cell disease.

血管判断性危机是发病率和死亡率的主要原因 镰状细胞病（SCD）。分子级联导致速度减慢 血管流程仍然难以捉摸。血流减慢，因此氧气 输送到组织很可能与镰状细胞的依从性有关 （SS）RBC到血管内皮，继发于继发的局部组织缺氧 SCD中常见的血液停滞和/或炎症。 SS RBC依从性可能 通过促进，通过反面表达来影响血流 内皮上的受体，SS RBC和 白细胞。我们假设SS RBC坚持内皮会产生 细胞氧化剂应激（由脂质过氧化 转录因子NF-KB的激活，导致表面表达 （SE）细胞粘附分子（CAM），ICAM-1，E-SELECTIN的子集的（SE） 和BCAM-1。同样，感染/炎症会导致CAM增加 表达。 VCAM-1的诱导SE导致更大的依从性 密集的SS RBC通过其alpha4beta1配体。坚持和 随后的PMN和单核细胞的二尿发生于增加的SE 凸轮，充当这些细胞中整联蛋白的反感应者。因为 NF-KB的激活部分通过由脂质过氧化 氧化应激（例如血管牙合），E计划确定是否 Bcl-2（一种脂质过氧化剂抑制的原子甘油）的过表达 培养的人脐静脉内皮细胞（HUVEC）将防止脂质 转染HUVEC时过氧化，NF-KB激活和CAM诱导 与SS RBC一起孵育。 致密的脱氧SS RBC在 RBC双层的外部传单，并通过PS粘附于HUVEC 受体，因此我们将确定LP和细胞因子是否会诱导 PS受体的表达，增强致密的脱氧SS RBC依从性。 此外，缺氧增加单核细胞跨内皮迁移， 这可能有助于血管牙合；因此，我们建议调查 缺氧诱导的PMN和单核细胞尿的机理。我们也会 检查SS RBC，LPS和细胞因子相互作用的机制 随着HUVEC改变CAM的表达，PMN的依从性和 单核细胞和增强的SS RBC依从性。而且，我们会的 研究来自不同不同的内皮细胞的凸轮诱导 血管床（肺微血管，肺动脉和大脑），以及 通过各种剪切影响的这种诱导的潜在差异 应力，模仿各种血管床普遍存在的条件。这些 完成的研究将提供有关新药理和/或 分子方法改善的临床表现 镰状细胞疾病中的血管牙合。