Apoptosis modulation by activin A and follistatin in human endometrial stromal cells

Abstract

Activin A is a growth factor that stimulates decidualization and is abundantly expressed in endometrial proliferative disorders. Nevertheless, whether it directly affects endometrial cell survival is still unknown. This study investigated the effects of activin A on total death and apoptosis rates and on tumor necrosis factor (TNF) release by human endometrial stromal cells (HESC). We performed a controlled prospective in vitro study using primary HESC cultures obtained from healthy reproductive age women (n = 11). Cells were treated with medium alone (control) or activin A (25 ng/mL) or activin A (25 ng/mL) and its antagonist follistatin (250 ng/mL). Apoptosis and total cell death were measured by flow cytometry, while TNF concentrations in culture media were quantified by ELISA. Activin A decreased the percentage of apoptotic/dead cells from 31% to 22% (p < 0.05, paired t-test) and reduced TNF levels in culture medium by 14%, but there was no linear correlation between TNF release and apoptotic rates. Both effects of activin A were reversed by follistatin. These findings indicate that activin A promotes HESC survival, possibly by a TNF-independent pathway. This mechanism may be critical to the actions of activin A upon stromal cell growth and differentiation in physiology and disease.

Chinese abstract

激活素A是一种刺激蜕膜的生长因子，在子宫内膜增殖性疾病中大量表达。然而它是否直接影响子宫内膜细胞的生存还是未知的。这篇研究的目的是调查激活素A对子宫内膜基质细胞（HESC）的总死亡细胞、细胞凋亡率及释放肿瘤坏死因子（TNF）的影响。我们在体外使用从健康育龄期女性（n=11）获得的子宫内膜基质细胞作为培养基进行了一个前瞻性对照研究。细胞分别用单独的媒介（对照组），加用激活素A（25ng/ml）或加用激活素A（25ng/ml）和激活素A的拮抗剂卵泡抑素（250ng/ml）。细胞凋亡及总死亡细胞使用流式细胞仪测定，肿瘤坏死因子由酶联免疫吸附方法（ELISA）进行定量。激活素A使总细胞死亡及细胞凋亡率从31%降至22%（P＜0.05，配对t检验），并且使肿瘤坏死因子的浓度降低了14%，但是肿瘤坏死因子和细胞凋亡之间并没有线性相关性。激活素A的作用均被卵泡抑素所逆转。这些发现预示激活素A促进子宫内膜基质细胞的生存，可能是通过肿瘤坏死因子独立的一个途径。这个机制可能是激活素A对基质细胞的生长和分化的作用处在生理和致病作用的临界。

• Activin A
• apoptosis
• endometrium
• follistatin

Declaration of interest

The authors report no conflicts of interest.

Research supported by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG, grant # APQ 02032/12) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant # 500049/2013-0).