ENDOTHELIAL DYSFUNCTION AND VASOOCCLUSION IN SICKLE CELL ANEMIA

血管闭塞危机是#年发病率和死亡率的主要原因。 镰状细胞病(SCD)。导致分子级联减慢的原因 血管流动仍然难以捉摸。血液流动减慢，因此氧气也减慢 向组织的传递很可能与镰状细胞的黏附有关 (SS)RBC至血管内皮细胞，继发于局限性组织缺氧 血瘀证和/或炎症在SCD中常见。SS RBC依从性可能 通过促进细胞表面反转录因子的表达而影响血流 内皮细胞上的受体、SS-RBC的额外结合和 白细胞。我们假设SS RBC与内皮细胞的黏附产生 细胞氧化应激(表现为过氧化脂质的形成和 转录因子核因子-kb)的激活，导致表面表达 (Se)细胞黏附分子(CAM)、ICAM-1、E-选择素 和BCAM-1。同样，感染/炎症会导致CAM的增加 表情。VCAM-1诱导的SE导致更大的粘附性 通过其α4β1配体致密SS RBC。坚守和 随后中性粒细胞和单核细胞的分裂通过增加的SE发生 作为这些细胞上整合素的反向受体。因为 核因子-kB的激活部分是通过产生过氧化脂质来实现的 氧化应激，如血管闭塞，计划确定是否 过氧化脂质抑制原癌基因bcl2在人卵巢癌组织中的过表达 培养的人脐静脉内皮细胞(HUVEC)可预防脂质 转染人脐静脉内皮细胞时的过氧化、核因子-KB激活和细胞间黏附分子的诱导 与SS RBC孵化。 致密脱氧SS红细胞显示磷脂酰丝氨酸(PS) 红细胞双层的外叶并通过PS与人脐静脉内皮细胞黏附 受体，所以我们将确定是否内毒素和细胞因子，它们诱导 PS受体的表达，增强致密脱氧SS红细胞的黏附。 此外，缺氧增加了单核细胞跨内皮细胞的迁移， 这可能导致血管闭塞；因此，我们建议研究 低氧诱导中性粒细胞和单核细胞分裂的机制。我们还将 探讨SS红细胞、内毒素和细胞因子相互作用的机制(S) 随着HUVEC改变CAM的表达，PMN和 单核细胞和SS-RBC粘附率增加。此外，我们还将 DISTINCT来源的内皮细胞对CAM的诱导作用 血管床(肺微血管、肺动脉和脑)，以及 不同剪切力对这种感应电势的影响 应激，模拟各种血管床中普遍存在的条件。这些 已完成的研究将提供对新的药理和/或 改善临床表现的分子生物学方法 镰状细胞病的血管闭塞。

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.