Tsai Jui-He, Chi Maggie M-Y, Schulte Maureen B, Moley Kelle H
Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri.
Biol Reprod. 2014 Feb 20;90(2):34. doi: 10.1095/biolreprod.113.113217. Print 2014 Feb.
Embryo implantation and development requires the endometrial stromal cells (ESCs) to undergo decidualization. This differentiation process requires glucose utilization, and blockade of the pentose phosphate pathway inhibits decidualization of ESCs both in vitro and in vivo. Glucose and fatty acids are energy substrates for many cell types, and fatty acid beta-oxidation is critical for embryo implantation. Here, we investigated whether beta-oxidation is required for decidualization of ESCs. As assessed by marker gene expression, decidualization of human primary ESCs was blocked by reducing activity of carnitine calmitoyltransferase I, the rate-limiting enzyme in beta-oxidation, either by short hairpin RNA-mediated silencing or by treatment with the inhibitor etomoxir. Ranolazine (RAN), a partial beta-oxidation inhibitor, blocked early decidualization of a human ESC line. However, decidualization resumed after several days, most likely due to a compensatory up-regulation of GLUT1 expression and an increase in glucose metabolism. Simultaneous inhibition of the beta-oxidation pathway with RAN and the pentose phosphate pathway with glucosamine (GlcN) impaired in vitro decidualization of human ESCs more strongly than inhibition of either pathway alone. These findings were confirmed in murine ESCs in vitro, and exposure to RAN plus GlcN inhibited decidualization in vivo in a deciduoma model. Finally, intrauterine implantation of time-release RAN and GlcN pellets reduced pup number. Importantly, pup number returned to normal after the end of the pellet-active period. This work indicates that both fatty acids and glucose metabolism pathways are important for ESC decidualization, and suggests novel pathways to target for the design of future nonhormonal contraceptives.
胚胎着床和发育需要子宫内膜基质细胞（ESC）进行蜕膜化。这个分化过程需要利用葡萄糖，而磷酸戊糖途径的阻断在体外和体内均会抑制ESC的蜕膜化。葡萄糖和脂肪酸是许多细胞类型的能量底物，脂肪酸β-氧化对于胚胎着床至关重要。在此，我们研究了ESC蜕膜化是否需要β-氧化。通过标记基因表达评估，无论是通过短发夹RNA介导的沉默还是用抑制剂依托莫昔治疗来降低β-氧化的限速酶肉碱脂酰转移酶I的活性，均可阻断人原代ESC的蜕膜化。雷诺嗪（RAN）是一种部分β-氧化抑制剂，可阻断人ESC系的早期蜕膜化。然而，几天后蜕膜化恢复，最可能的原因是GLUT1表达的代偿性上调和葡萄糖代谢增加。与单独抑制任何一条途径相比，同时用RAN抑制β-氧化途径和用氨基葡萄糖（GlcN）抑制磷酸戊糖途径对人ESC的体外蜕膜化有更强的损害。这些发现在体外的小鼠ESC中得到证实，并且在蜕膜瘤模型中，暴露于RAN加GlcN会抑制体内蜕膜化。最后，子宫内植入缓释RAN和GlcN微丸会减少幼崽数量。重要的是，在微丸活性期结束后幼崽数量恢复正常。这项工作表明脂肪酸和葡萄糖代谢途径对ESC蜕膜化都很重要，并为未来非激素避孕药的设计提出了新的靶向途径。
