The effect of laminar and disturbed flow on endothelial glucose metabolism

内皮代谢最近重新成为调节血管功能的强大工具。然而， 研究完全集中在通过 PFKFB3 调节糖酵解通量及其对血管生成的影响。小的是 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。 内皮细胞不断受到流动血液的剪切应力。内皮细胞稳定 层流表达静态表型，通过控制增殖维持血管稳态， 通透性、炎症和血管张力。振荡扰动血流中的内皮细胞表达动脉粥样硬化 具有升高的增殖、通透性和炎症粘附分子表达的倾向表型 以及一氧化氮生成受损（定义为内皮功能障碍）。扰动流动区域与 随后的病理性血管重塑，包括动脉粥样硬化斑块的形成。 最近，稳定层流中的内皮细胞部分通过 KLF2 介导的抑制来减少糖酵解 PFKFB3。然而，同时 KLF2 和 PFKFB3 过表达并没有完全恢复糖酵解率， 表明其他代谢介质也参与其中。我们的数据显示，内皮细胞处于稳定状态 层流在更短的时间内减少糖酵解通量，而 PFKFB3 表达没有变化，并且内皮细胞 振荡扰动流中的细胞不会降低糖酵解通量。我们的数据还表明流量调节 己糖胺生物合成途径，糖酵解的一个侧分支，控制蛋白质 O-GlcNAc 酰化和乙酰基 CoA，对于脂质合成和组蛋白乙酰化至关重要。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。 该项目的目标是了解稳定层流和振荡扰动流如何不同地影响 大血管内皮糖酵解通量、HBP 和乙酰 CoA 代谢。我们假设平均剪力 大于 12 dynes/cm2 的压力会降低糖酵解通量、eNOS O-GlcNAcNAc 化和乙酰辅酶 A，从而促进 动脉粥样硬化保护内皮表型。为了检验这个假设，我们将 (1) 确定层流和层流的稳定程度 振荡扰动血流调节内皮糖酵解通量； (2) 确定层流的稳定程度 振荡扰动流影响 eNOS O-GlcNAcylation； (3) 确定乙酰辅酶A如何改变 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，我们将结合使用体外和离体 实验发现葡萄糖代谢随流量变化的潜在机制。我们的团队是独一无二的 准备开展这项研究，拥有内皮血流动力学、代谢质谱、O- GlcNAcylation 和离体血管分析。这些数据将通过创建新的研究领域来改变该领域 处于血流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.