Abstract：
Phenotypic changes to endometrial epithelial cells underpin receptivity to embryo implantation at the onset of pregnancy but the effect of hyperglycemia on these processes remains poorly understood. Here, we show that physiological levels of glucose (5 mM) abolished receptivity in the endometrial epithelial cell line, Ishikawa. However, embryo attachment was supported by 17 mM glucose as a result of glucose flux through the hexosamine biosynthetic pathway (HBP) and modulation of cell function via protein O-GlcNAcylation. Pharmacological inhibition of HBP or protein O-GlcNAcylation reduced embryo attachment in cocultures at 17 mM glucose. Mass spectrometry analysis of the O-GlcNAcylated proteome in Ishikawa cells revealed that myosin phosphatase target subunit 1 (MYPT1) is more highly O-GlcNAcylated in 17 mM glucose, correlating with loss of its target protein, phospho-myosin light chain 2, from apical cell junctions of polarized epithelium. Two-dimensional (2-D) and three-dimensional (3-D) morphologic analysis demonstrated that the higher glucose level attenuates epithelial polarity through O-GlcNAcylation. Inhibition of Rho (ras homologous)A-associated kinase (ROCK) or myosin II led to reduced polarity and enhanced receptivity in cells cultured in 5 mM glucose, consistent with data showing that MYPT1 acts downstream of ROCK signaling. These data implicate regulation of endometrial epithelial polarity through RhoA signaling upstream of actomyosin contractility in the acquisition of endometrial receptivity. Glucose levels impinge on this pathway through O-GlcNAcylation of MYPT1, which may impact endometrial receptivity to an implanting embryo in women with diabetes.NEW & NOTEWORTHY Understanding how glucose regulates endometrial function will support preconception guidance and/or the development of targeted interventions for individuals living with diabetes wishing to embark on pregnancy. We found that glucose can influence endometrial epithelial cell receptivity to embryo implantation by regulating posttranslational modification of proteins involved in the maintenance of cell polarity. Impaired or inappropriate endometrial receptivity could contribute to fertility and/or early pregnancy complications caused by poor glucose control.
摘要：
子宫内膜上皮细胞的表型变化支持妊娠开始时对胚胎植入的容受性，但高血糖对这些过程的影响仍知之甚少。在这里，我们显示，生理水平的葡萄糖（5mM）消除子宫内膜上皮细胞系的容受性，石川。然而,由于通过己糖胺生物合成途径（HBP）的葡萄糖通量和通过蛋白质O-GlcNAcylation调节细胞功能，因此17mM葡萄糖支持了胚胎附着。在17mM葡萄糖的共培养物中,HBP或蛋白质O-GlcNAcylation的药理学抑制降低了胚胎附着。Ishikawa细胞中O-GlcNAcylated蛋白质组的质谱分析显示，肌球蛋白磷酸酶靶亚基1（MYPT1）在17mM葡萄糖中的O-GlcNAcylated更高，与其靶蛋白的丢失相关，磷酸化肌球蛋白轻链2，来自极化上皮的顶端细胞连接。2D和3D形态学分析表明,较高的葡萄糖水平通过O-GlcNAcylation减弱上皮极性。抑制RhoA相关激酶（ROCK）或肌球蛋白II导致在5mM葡萄糖中培养的细胞的极性降低和接受性增强，与显示MYPT1作用于ROCK信号下游的数据一致。这些数据暗示在获得子宫内膜容受性时，通过肌动球蛋白收缩性上游的RhoA信号调节子宫内膜上皮极性。葡萄糖水平通过MYPT1的O-GlcNAcylation影响该途径，这可能会影响糖尿病女性子宫内膜对植入胚胎的容受性。
