Hyperandrogen enhances apoptosis of human ovarian granulosa cells via up-regulation and demethylation of PDCD4

Abstract

Apoptosis of granulosa cells (GCs) induced by hyperandrogen plays a key role in the pathogenesis of polycystic ovary syndrome (PCOS). However, the mechanism of androgen-induced apoptosis of GCs has not been clarified to date. Recent studies have reported that PDCD4 expression is higher in PCOS patients and might be a key factor in PCOS progression. In this study, we aimed to investigate the role of PDCD4 in regulating apoptosis of human GCs and whether hyperandrogen regulate PDCD4 expression through DNA methylation. Overexpression of PDCD4 in human ovarian granulosa cell line KGN cells promoted cells apoptosis. Meanwhile, expression of caspase-3 and caspase-9 were significantly elevated. High concentration of testosterone treatment resulted in up-regulation of PDCD4 and a significant increase of apoptosis in KGN cells. In addition, knockdown of PDCD4 in KGN cells treated with high concentration of testosterone abolished the hyperandrogen-induced apoptosis. Furthermore, high concentration of testosterone down-regulated DNMT1, DNMT3A and DNMT3B expression and the methylation level in the promoter region of PDCD4 was decreased. In conclusion, PDCD4 can promote apoptosis of human ovarian GCs. The mechanism of hyperandrogen-induced apoptosis may be mediated by PDCD4. Furthermore, the up-regulation of PDCD4 induced by hyperandrogen may through demethylation of its promoter regions.

摘要

高雄激素诱导的颗粒细胞（GCs）凋亡在多囊卵巢综合征（PCOS）的发病机理中起着关键作用。然而, 迄今为止, 尚不清楚雄激素诱导的GCs凋亡的机制。最近的研究报道, PDCD4在PCOS患者中表达较高, 可能是PCOS进展的关键因素。在这项研究中, 我们旨在研究PDCD4在调节人GCs凋亡中的作用以及高雄激素是否通过DNA甲基化调节PDCD4的表达。PDCD4在人卵巢颗粒细胞KGN细胞系中的过表达促进细胞凋亡。同时, caspase-3和caspase-9的表达明显升高。高浓度的睾丸激素治疗导致PDCD4上调, 并显着增加KGN细胞的凋亡。另外, 用高浓度睾丸激素处理PDCD4敲低的KGN细胞消除了高雄激素诱导的细胞凋亡。此外, 高浓度的睾丸激素下调了DNMT1, DNMT3A和DNMT3B的表达, 降低了PDCD4启动子区域的甲基化水平。总之, PDCD4可以促进人卵巢GCs的凋亡；高雄激素诱导的细胞凋亡机制可能由PDCD4介导。此外, 高雄激素诱导的PDCD4的上调可能是通过其启动子区域的脱甲基化。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

KEYWORDS:

• Androgen
• ovarian granulosa cells
• apoptosis
• PDCD4
• methylation

Acknowledgements

We thank Dr Olubunmi Afonja in New York University for providing the PDCD4 constructs.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant [No: 81601255].