Mouse Embryonic Stem Cells Established in Physiological-Glucose Media Express the High KM Glut2 Glucose Transporter Expressed by Normal Embryos
Mouse Embryonic Stem Cells Established in Physiological-Glucose Media Express the High KM Glut2 Glucose Transporter Expressed by Normal Embryos
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DOI：
10.5966/sctm.2013-0093
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发表时间：
2013-12-01
影响因子：
6
通讯作者：
Loeken, Mary R.
中科院分区：
文献类型：
--
作者：
Jung, Jin Hyuk;Wang, Xiao Dan;Loeken, Mary R.
Glut2是着床前和着床后早期胚胎表达的促性葡萄糖转运蛋白之一。谷氨酸2对胚胎10.5天前的存活很重要。Glut2 K-M（约为16 mmol/l）明显高于生理葡萄糖浓度（约为5.5 mmol/l），表明Glut2在正常情况下发挥除葡萄糖运输之外的一些重要功能。然而，当细胞外葡萄糖浓度高于Glut2 K-M时，Glut2可以有效地运输葡萄糖。含有25 mmol/l葡萄糖的培养基被广泛用于胚胎干细胞（ESCs）的建立和繁殖。谷氨酰胺介导的胚胎葡萄糖摄取诱导氧化应激，可导致胚胎细胞死亡。在这里，我们验证了在生理葡萄糖(5.5 mmol/(iter)培养基中分离的低糖胚胎干细胞（LG-ESCs）表达功能性Glut2葡萄糖转运蛋白的假设。将LG-ESCs与仅在高糖培养基中培养的常规D3 ESCs进行比较。LG-ESCs表达Glut2 mRNA和蛋白的水平远高于D3 ESCs，并且2-脱氧葡萄糖转运表现出高的Michaelis-Menten动力学，而D3 ESCs则没有。25 mmol/l葡萄糖诱导pg - escs氧化应激，抑制pg - escs神经前体中受高血糖抑制的胚胎基因Pax3的表达。这些影响在D3 ESCs中未观察到。这些发现表明，在生理性葡萄糖培养基中分离的ESCs保留了一个由胚胎表达的功能性Glut2转运蛋白。这些细胞更适合研究早期胚胎的代谢调节特征，并可能有利于治疗应用。
Glut2 is one of the facilitative glucose transporters expressed by preimplantation and early post-implantation embryos. Glut2 is important for survival before embryonic day 10.5. The Glut2 K-M (similar to 16 mmol/liter) is significantly higher than physiologic glucose concentrations (similar to 5.5 mmol/liter), suggesting that Glut2 normally performs some essential function other than glucose transport. Nevertheless, Glut2 efficiently transports glucose when extracellular glucose concentrations are above the Glut2 K-M. Media containing 25 mmol/liter glucose are widely used to establish and propagate embryonic stem cells (ESCs). Glut2-mediated glucose uptake by embryos induces oxidative stress and can cause embryo cell death. Here we tested the hypothesis that low-glucose embryonic stem cells (LG-ESCs) isolated in physiological-glucose (5.5 mmol/(iter) media express a functional Glut2 glucose transporter. LG-ESCs were compared with conventional D3 ESCs that had been cultured only in high-glucose media. LG-ESCs expressed Glut2 mRNA and protein at much higher levels than D3 ESCs, and 2-deoxyglucose transport by LG-ESCs, but not D3 ESCs, exhibited high Michaelis-Menten kinetics. Glucose at 25 mmol/liter induced oxidative stress in LG-ESCs and inhibited expression of Pax3, an embryo gene that is inhibited by hyperglycemia, in neuronal precursors derived from LG-ESCs. These effects were not observed in D3 ESCs. These findings demonstrate that ESCs isolated in physiological-glucose media retain a functional Glut2 transporter that is expressed by embryos. These cells are better suited to the study of metabolic regulation characteristic of the early embryo and may be advantageous for therapeutic applications.