5Lipoxygenase-mediated vasculopathy in HHcy

5 HHcy 中脂氧合酶介导的血管病变

基本信息

批准号：
8438046
负责人：
DOMENICO PRATICO
金额：
$ 36.89万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-01 至 2017-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8438046
关键词：
Address Aging Amino Acids Amyloid Amyloid beta-Protein Arachidonate 5-Lipoxygenase Arteries Biochemical Biological Assay Blood Vessels Blood flow Brain Cells Cerebral Amyloid Angiopathy Cerebrum Chronic Coronary heart disease DNA DNA Methylation DNA Methyltransferase DNA Modification Methylases Data Deposition Development Drainage procedure Endothelial Cells Enzymes Epigenetic Process Event Extracellular Space Folate Functional disorder Future Genes Goals Hemorrhage Homocysteine Homocystine Human Hydrolysis Hyperhomocysteinemia Incidence Inflammation Inflammatory Knock-out Lesion Link Lymphatic Mediating Mediator of activation protein Metabolic Pathway Methionine Methylation Methyltransferase Modification Mus Neuraxis Pathway interactions Peptides Pharmaceutical Preparations Phenotype Plasma Production Proteins Reaction Risk Factors Role S-Adenosylhomocysteine S-Adenosylmethionine Secondary to Smooth Muscle Myocytes Stimulus Stroke Sulfur Testing Time Tissues Translating Up-Regulation Vascular Diseases Vitamin B 12 Vitamin B6 cerebral artery cerebrovascular in vivo inhibitor/antagonist mortality mouse model novel promoter public health relevance response vascular inflammation

项目摘要

DESCRIPTION (provided by applicant): Elevated levels of total plasma homocysteine (Hcy), termed hyperhomocysteinemia (HHcy), are associated with increased incidence and mortality of chronic vascular diseases including coronary heart disease and stroke. However, the underlying biochemical mechanisms remain unknown. HHcy results in a significant elevation of intracellular levels of S- adenosylhomocysteine (SAH), a potent endogenous inhibitor of methyl-transfer reactions. Recently, we found that HHcy up-regulates the 5-Lipoxygenase (5- LO), an enzyme abundantly present in the vasculature, where it induces an increased formation of the amyloid beta peptide (Abeta) within the endothelial cells (EC). Once formed Abeta is rapidly eliminated along perivascular lymphatic drainage pathways. However, if the total amount of Abeta produced overcomes this ability, the peptide will accumulate in the arterial walls resulting in vascular inflammation and dysfunction. With time this condition will develop in amyloid angiopathy, which is characterized by excessive Abeta deposited also in the extracellular space of the artery wall, loss of smooth muscle cells and recruitment of circulating inflammatory cells. Taken together these data suggest a possible involvement of 5-LO in the HHcy-dependent vascular dysfunction and development of amyloid angiopathy, and support our central hypothesis: HHcy results in elevated intracellular SAH which by activating 5-LO induces an over- production of Abeta and its accumulation in the vasculature with subsequent vascular inflammation, endothelial dysfunction (ED) and ultimately amyloid angiopathy. To test our hypothesis we propose 3 linked specific Aims. In the first one, we will assess 5-LO activation and its contribution to vascular inflammation, ED and amyloid angiopathy in a mouse model of HHcy, the Tg-hCBS Cbs-/- mice. In the second one, we will determine the mechanisms by which HHcy induces 5-LO upregulation, and examine the role and mechanisms by which activated 5-LO regulates Abeta formation in EC. In the third one, we will establish the role of HHcy, and 5-LO upregulation in the development of the pathological vascular phenotype of the Tg-hCBS Cbs-/- mice.

描述（由申请人提供）：血浆总同型半胱氨酸（Hcy）水平升高，称为高同型半胱氨酸血症（HHcy），与慢性血管疾病（包括冠心病和中风）的发病率和死亡率增加相关。然而，潜在的生化机制仍然未知。 HHcy 导致细胞内 S-腺苷高半胱氨酸 (SAH) 水平显着升高，SAH 是甲基转移反应的有效内源抑制剂。最近，我们发现 HHcy 上调 5-脂氧合酶 (5-LO)，这是一种大量存在于脉管系统中的酶，它诱导内皮细胞 (EC) 内淀粉样 β 肽 (Abeta) 的形成增加。 Abeta 一旦形成，就会沿着血管周围淋巴引流途径迅速消除。然而，如果产生的 Abeta 总量超过了这种能力，肽就会积聚在动脉壁中，导致血管炎症和功能障碍。随着时间的推移，这种情况将发展为淀粉样血管病，其特征是动脉壁细胞外间隙中也沉积有过量的Abeta、平滑肌细胞的损失和循环炎症细胞的募集。综上所述，这些数据表明 5-LO 可能参与 HHcy 依赖性血管功能障碍和淀粉样血管病的发展，并支持我们的中心假设：HHcy 导致细胞内 SAH 升高，通过激活 5-LO 诱导 Abeta 过量产生及其在脉管系统中的积累，导致血管炎症、内皮功能障碍 (ED) 和最终的淀粉样血管病。为了检验我们的假设，我们提出了 3 个相互关联的具体目标。在第一个实验中，我们将在 HHcy 小鼠模型（Tg-hCBS Cbs-/- 小鼠）中评估 5-LO 激活及其对血管炎症、ED 和淀粉样血管病的影响。在第二部分中，我们将确定 HHcy 诱导 5-LO 上调的机制，并检查激活的 5-LO 在 EC 中调节 Abeta 形成的作用和机制。在第三部分中，我们将确定 HHcy 和 5-LO 上调在 Tg-hCBS Cbs-/- 小鼠病理血管表型发展中的作用。