The effect of laminar and disturbed flow on endothelial glucose metabolism

近年来，内皮细胞代谢作为调节血管功能的有力工具再次出现。然而，在这方面， 研究完全集中在经由PFKFB 3的糖酵解通量调节及其在血管生成中的作用。之甚少 了解内皮细胞代谢如何影响健康和疾病中的大血管内皮功能。 内皮细胞不断地暴露于来自流动血液的剪切应力。内皮细胞稳定 层流表达静止表型，通过控制增殖维持血管稳态， 渗透性、炎症和血管张力。振荡扰动流中的内皮细胞表达动脉粥样硬化， 易发生表型，增殖、通透性和炎性粘附分子表达升高， 以及受损的NO产生（定义为内皮功能障碍）。扰动流区域与 随后的病理性血管重塑包括动脉粥样硬化斑块的发展。 最近，稳定层的内皮细胞通过KLF 2介导的对糖酵解的抑制部分地减少了糖酵解。 PFKFB 3.然而，同时KLF 2和PFKFB 3过表达不能完全恢复糖酵解速率， 这表明其他代谢介质也参与其中。我们的数据表明，内皮细胞在稳定 层流在较短时间内减少了糖酵解通量，而PFKFB 3表达没有变化， 振荡扰动流中的细胞不降低糖酵解通量。我们的数据还表明，流量调节 己糖胺生物合成途径，糖酵解的侧分支，其控制蛋白质O-GlcNAc化，和乙酰基 辅酶A，这是关键的脂质合成和组蛋白乙酰化。我们才刚刚开始发现 剪切应力影响内皮葡萄糖代谢和下游途径的机制。 我们的长期目标是调节葡萄糖代谢，以减少血流紊乱时的内皮功能障碍。 这个项目的目标是了解如何稳定层流和振荡扰动流差异影响 大血管内皮糖酵解通量、HBP和乙酰辅酶A代谢。我们假设平均切变 大于12达因/cm 2的应力降低糖酵解通量、eNOS O-GlcNAc酰化和乙酰辅酶A，以促进糖酵解。 动脉粥样硬化保护内皮表型。为了检验这一假设，我们将（1）确定如何稳定层流和 振荡扰动流调节内皮糖酵解通量;（2）确定如何稳定层流和 振荡扰动流影响eNOS O-GlcNAc酰化;以及（3）确定在eNOS中如何改变乙酰辅酶A。 流动影响脂质合成和组蛋白乙酰化 由于动脉粥样硬化是一种代谢改变的疾病，我们将使用体外和离体的组合， 实验，以发现葡萄糖代谢与流量的变化机制。我们的团队是独一无二的 准备从事这项研究，在内皮血流动力学，代谢质谱，O- GlcNAc化和离体血管分析。这些数据将通过创建一个新的研究领域来改变该领域 血液动力学和代谢组学的交叉点。

Endothelial metabolism has recently re-emerged as a powerful tool to regulate vascular function. However, studies have focused entirely on glycolytic flux regulation via PFKFB3 and its effects in angiogenesis. Little is known about how endothelial cell metabolism impacts macrovascular endothelial function in health and disease. Endothelial cells are constantly exposed to shear stress from the flowing blood. Endothelial cells in steady laminar flow express a quiescent phenotype, maintaining vascular homeostasis through control of proliferation, permeability, inflammation, and vascular tone. Endothelial cells in oscillating disturbed flow express an athero- prone phenotype with elevated proliferation, permeability, and inflammatory adhesion molecule expression as well as impaired NO production (defined as endothelial dysfunction). Disturbed flow regions are linked to subsequent pathological vascular remodeling including atherosclerotic plaque development. Recently, endothelial cells in steady laminar reduced glycolysis partially via KLF2-mediated repression of PFKFB3. However, concurrent KLF2 and PFKFB3 overexpression did not fully restore glycolytic rate, suggesting that other metabolic mediators are involved. Our data show that endothelial cells in steady laminar flow reduce glycolytic flux at shorter times with no change in PFKFB3 expression, and that endothelial cells in oscillating disturbed flow do not decrease glycolytic flux. Our data also show that flow regulates the hexosamine biosynthetic pathway, a side branch of glycolysis which controls protein O-GlcNAcylation, and acetyl CoA, which is critical to lipid synthesis and histone acetylation. We are only beginning to discover mechanisms by which shear stress affects endothelial glucose metabolism and downstream pathways. Our long term goal is to modulate glucose metabolism to reduce endothelial dysfunction in disturbed flow. The goal of this project is to understand how steady laminar and oscillating disturbed flow differentially affect macrovascular endothelial glycolytic flux, the HBP, and acetyl CoA metabolism. We hypothesize that mean shear stress greater than 12 dynes/cm2 reduces glycolytic flux, eNOS O-GlcNAcylation, and acetyl CoA to promote an athero-protective endothelial phenotype. To test this hypothesis, we will (1) determine how steady laminar and oscillating disturbed flow regulate endothelial glycolytic flux; (2) determine how steady laminar and oscillating disturbed flow affect eNOS O-GlcNAcylation; and (3) determine how altered acetyl CoA in flow impacts lipid synthesis and histone acetylation Since atherosclerosis is a disease of altered metabolism, we will use a combination of in vitro and ex vivo experiments to discover mechanisms underlying changes in glucose metabolism with flow. Our team is uniquely prepared to pursue this research, with expertise in endothelial hemodynamics, metabolic mass spectrometry, O- GlcNAcylation, and ex vivo vessel analysis. These data will transform the field by creating a new research area at the intersection of hemodynamics and metabolomics.