OBJECTIVE Endothelial cells exposed to laminar shear stress express a thick glycocalyx on their surface that plays an important role in reducing vascular permeability and endothelial anti-inflammatory, antithrombotic, and antiangiogenic properties. Production and maintenance of this glycocalyx layer is dependent on cellular carbohydrate synthesis, but its regulation is still unknown. Approach and Results: Here, we show that biosynthesis of the major structural component of the endothelial glycocalyx, hyaluronan, is regulated by shear. Both in vitro as well as in in vivo, hyaluronan expression on the endothelial surface is increased on laminar shear and reduced when exposed to oscillatory flow, which is regulated by KLF2 (Krüppel-like Factor 2). Using a CRISPR-CAS9 edited small tetracysteine tag to endogenous HAS2 (hyaluronan synthase 2), we demonstrated increased translocation of HAS2 to the endothelial cell membrane during laminar shear. Hyaluronan production by HAS2 was shown to be further driven by availability of the hyaluronan substrates UDP-glucosamine and UDP-glucuronic acid. KLF2 inhibits endothelial glycolysis and allows for glucose intermediates to shuttle into the hexosamine- and glucuronic acid biosynthesis pathways, as measured using nuclear magnetic resonance analysis in combination with 13C-labeled glucose. CONCLUSIONS These data demonstrate how endothelial glycocalyx function and functional adaptation to shear is coupled to KLF2-mediated regulation of endothelial glycolysis.

中文翻译：

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糖基化合成确定内皮糖萼结构的剪切应力调节。

目的暴露于层流切应力的内皮细胞在其表面表达浓厚的糖萼，这在降低血管通透性和内皮抗炎，抗血栓形成和抗血管生成特性中起着重要作用。该糖萼层的产生和维持依赖于细胞碳水化合物的合成，但是其调节仍是未知的。方法和结果：在这里，我们表明内皮糖萼的主要结构成分，透明质酸的生物合成受剪切作用调节。无论是在体内还是体外，透明质酸在内皮层表面的表达在层流剪切作用下均会增加，而在受到KLF2（Krüppel样因子2）调节的振荡流的作用下会降低。使用CRISPR-CAS9编辑的小四半胱氨酸标签对内源性HAS2（透明质酸合酶2）进行编码，我们证明了层流剪切过程中HAS2向内皮细胞膜的转运增加。透明质酸底物UDP-葡萄糖胺和UDP-葡萄糖醛酸的可用性进一步推动了HAS2的乙酰透明质酸生产。KLF2抑制内皮糖酵解，并允许葡萄糖中间体穿入六胺和葡萄糖醛酸的生物合成途径，这是使用核磁共振分析结合13C标记的葡萄糖测得的。结论这些数据证明了内皮糖萼的功能和对剪切的功能适应性如何与KLF2介导的内皮糖酵解调节相结合。透明质酸底物UDP-葡萄糖胺和UDP-葡萄糖醛酸的可用性进一步推动了HAS2的乙酰透明质酸生产。KLF2抑制内皮糖酵解，并允许葡萄糖中间体穿入六胺和葡萄糖醛酸的生物合成途径，这是使用核磁共振分析结合13C标记的葡萄糖测得的。结论这些数据证明了内皮糖萼的功能和对剪切的功能适应性如何与KLF2介导的内皮糖酵解调节相结合。透明质酸底物UDP-葡萄糖胺和UDP-葡萄糖醛酸的可用性进一步推动了HAS2的乙酰透明质酸生产。KLF2抑制内皮糖酵解，并允许葡萄糖中间体穿入六胺和葡萄糖醛酸的生物合成途径，这是使用核磁共振分析结合13C标记的葡萄糖测得的。结论这些数据证明了内皮糖萼的功能和对剪切的功能适应性如何与KLF2介导的内皮糖酵解调节相结合。