The expression of hepatoma upregulated protein in human endometrium during the menstrual cycle

Abstract

Aims

Human endometrium resists embryo implantation except during the window period. Currently, uterine HURP expression is known to be involved in endometrial stromal proliferation during embryo implantation of mice. Thus, we demonstrated hepatoma up-regulated protein (HURP) expression in the human endometrium during the menstrual cycle, as well as HURP regulation in endometrial stromal cells (ESCs).

Materials and methods

We collected human endometrial samples from different menstrual cycle phases (early/late proliferative, and early/mid/late secretory), and then analyzed these samples by immunohistochemistry, reverse transcription-polymerase chain reaction, and Western blotting. We also assessed the effects of two sex-steroid hormones, 17β-estradiol (E2) and 4-pregnene-3,20-dione (P4) on the cultured stromal cells.

Results

HURP protein was localized to the nucleus of the endometrial both epithelial and stromal cells in all stages. Also, HURP mRNA and protein in human endometrial tissue was significantly up-regulated during late-proliferative and secretory phase, compared with early-proliferative phase. In ESCs, HURP expression was regulated by E2, but not P4.

Conclusions

We indicated that cyclic changes in HURP expression in human normal ESC strongly suggested up-regulation by estrogen. Taken together, since estrogen responses are fundamental in endometrial biology, uterine expression of HURP may be involved in female reproductive function during the menstrual cycle.

摘要

目的：除窗口期, 人子宫内膜抵制胚胎着床。目前已知子宫HURP表达参与小鼠胚胎着床期的子宫内膜间质的增殖。因此, 我们证实了肝细胞瘤上调蛋白（HURP）在月经周期子宫内膜的表达, 以及HURP在子宫内膜基质细胞（ESCs）中的调节。

材料与方法：收集不同月经周期阶段（增殖早期/晚期、分泌早期/中期/晚期）的人子宫内膜样本, 采用免疫组化、逆转录-聚合酶链反应、Western blotting等方法进行分析。我们还评估了两种性类固醇激素, 17β-雌二醇（E2）和4-孕烯-3, 20-二酮（P4）对培养的基质细胞的影响。

结果：HURP蛋白定位于子宫内膜上皮细胞和间质细胞的细胞核。此外, 人子宫内膜组织中HURP 的mRNA和蛋白质在增殖晚期和分泌期较增殖早期显著上调。在ESCs中, HURP的表达受E2的调控, 而非P4的调控。

结论：我们认为, 人类正常ESC中HURP表达的周期性变化强烈, 提示雌激素上调。综上所述, 由于雌激素反应是子宫内膜生物学基础, 所以子宫HURP的表达可能参与月经周期的女性生殖功能。

Keywords:

• Hepatoma upregulated protein
• endometrium
• endometrial stromal cell
• human
• uterus
• menstrual cycle

Acknowledgments

We thank Miss Yoko Niwa for the technical assistance with immunohistochemistry, and the Central Research Laboratory of Shiga University of Medical Science for valuable technical assistance. We would also like to thank Enago (www.enago.jp) for the English language review.

Disclosure statement

No potential conflict of interest was reported by the author(s).