Milne S A, Perchick G B, Boddy S C, Jabbour H N
Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, Edinburgh, United Kingdom EH3 9ET.
J Clin Endocrinol Metab. 2001 Sep;86(9):4453-9. doi: 10.1210/jcem.86.9.7856.
This study was designed to elucidate the sites of synthesis and action of PGE(2) in the nonpregnant human uterus across the menstrual cycle. The sites of expression of PGE synthase and synthesis of PGE(2) were investigated by immunohistochemistry using full thickness uterine biopsies. Expression of PGE synthase and synthesis of PGE(2) were localized to glandular epithelial and endothelial cells in both basalis and functionalis regions of the human endometrium. By contrast, stromal staining was predominantly localized in the functionalis layer. Some cyclical variation in expression of PGE synthase and PGE(2) synthesis was observed, with reduced expression/synthesis detected in the stromal compartment of the functionalis during the late secretory phase of the menstrual cycle. Subsequently, we assessed the site of action of PGE(2) by investigating the expression of two PGE(2) receptor isoforms, namely EP2 and EP4. Cyclical variation in endometrial EP2 and EP4 receptor mRNA expression was quantified by TaqMan quantitative RT-PCR using RNA isolated from endometrial tissue collected across the menstrual cycle. No differences in EP2 receptor mRNA expression were detected; however, EP4 receptor mRNA expression was significantly higher in late proliferative stage (P < 0.05) than in early, mid, and late secretory stage endometrium. Expression patterns of EP2 and EP4 receptors were localized by nonradioactive in situ hybridization using fluorescein isothiocyanate end- labeled oligonucleotide probes. Expression of both receptors was observed in endometrial glandular epithelial and vascular cells, with no notable spatial or temporal variation. Finally, signaling of EP2/EP4 receptors was assessed by investigating cAMP generation in vitro after stimulation with PGE(2). Endometrial cAMP generation in response to PGE(2) was significantly greater in proliferative tissue compared with early and midsecretory stage tissue (3.77 +/- 0.85 vs. 1.96 +/- 0.28 and 1.38 +/- 0.23, respectively; P < 0.05). In conclusion, this study demonstrates glandular and vascular coexpression of PGE synthase, PGE(2), EP2, and EP4 receptors and suggests an autocrine/paracrine role for PGE(2) in epithelial/endothelial cell function in the human endometrium.
本研究旨在阐明月经周期中非妊娠人类子宫内前列腺素E2（PGE2）的合成部位及作用位点。采用全层子宫活检组织，通过免疫组织化学法研究PGE合成酶的表达部位及PGE2的合成情况。PGE合成酶的表达及PGE2的合成定位于人类子宫内膜基底层和功能层的腺上皮细胞及内皮细胞。相比之下，基质染色主要定位于功能层。观察到PGE合成酶的表达及PGE2的合成存在一些周期性变化，在月经周期分泌晚期，功能层基质区的表达/合成减少。随后，我们通过研究两种PGE2受体亚型（即EP2和EP4）的表达来评估PGE2的作用位点。使用从月经周期不同阶段收集的子宫内膜组织分离的RNA，通过TaqMan定量逆转录聚合酶链反应（RT-PCR）对子宫内膜EP2和EP4受体mRNA表达的周期性变化进行定量分析。未检测到EP2受体mRNA表达的差异；然而，EP4受体mRNA表达在增殖晚期（P<0.05）显著高于分泌早期、中期和晚期的子宫内膜。使用异硫氰酸荧光素末端标记的寡核苷酸探针，通过非放射性原位杂交对EP2和EP4受体的表达模式进行定位。在子宫内膜腺上皮细胞和血管细胞中均观察到两种受体的表达，且无明显的空间或时间变化。最后，通过研究PGE2刺激后体外环磷酸腺苷（cAMP）的生成来评估EP2/EP4受体的信号传导。与分泌早期和中期组织相比，增殖期组织对PGE2刺激产生的子宫内膜cAMP显著增加（分别为3.77±0.85与1.96±0.28和1.38±0.23；P<0.05）。总之，本研究证明了PGE合成酶、PGE2、EP2和EP4受体在腺上皮和血管中的共表达，并提示PGE2在人类子宫内膜上皮/内皮细胞功能中具有自分泌/旁分泌作用。
