Involvement of the bone morphogenetic protein/receptor system during follicle development in the bovine ovary: Hormonal regulation of the expression of bone morphogenetic protein 7 (BMP-7) and its receptors (ActRII and ALK-2)
Involvement of the bone morphogenetic protein/receptor system during follicle development in the bovine ovary: Hormonal regulation of the expression of bone morphogenetic protein 7 (BMP-7) and its receptors (ActRII and ALK-2)
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DOI：
10.1016/j.mce.2006.01.015
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发表时间：
2006-04-25
影响因子：
4.1
通讯作者：
Miyamoto, A
中科院分区：
文献类型：
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作者：
Shimizu, T;Jayawardana, BC;Miyamoto, A
骨形态发生蛋白（BMPs）是卵泡生长和发育的关键因素。在BMP配体中，以ActRII作为其II型受体的BMP - 7，与作为其I型受体的ALK - 2紧密结合。然而，在牛卵泡发育过程中它们的受体是否表达以及控制其表达的调节机制仍然未知。本研究的目的是通过检测促卵泡激素（FSH）和雌二醇（E2）对牛颗粒细胞（GCs）中ActRII和ALK - 2 mRNA表达的调节作用，来阐明BMP - 7受体系统在卵泡选择中的作用。为了观察mRNA表达，从母牛获取卵泡，并将颗粒细胞分为两组：选择前卵泡（PRF；平均直径为7mm且雌二醇含量低的卵泡）和选择后卵泡（POF；平均直径为15mm且雌二醇含量高的卵泡）。从抽吸的卵泡中获取卵泡膜细胞（TC）层和颗粒细胞。在体外研究中，从直径为4 - 7mm的牛卵泡中获取颗粒细胞，并在含有10%胎牛血清的杜尔贝科改良伊格尔/F12（DMEM/F - 12）培养基中培养24小时。然后将培养基更换为无血清的DMEM/F - 12，并添加不同剂量的E2（1、10、100ng/ml）、FSH（1、5、10ng/ml）或1ng/ml的E2与不同FSH剂量（1、5、10ng/ml）的组合。从颗粒细胞中提取总RNA，并使用LightCycler通过定量PCR方法评估ActRII和ALK - 2的mRNA表达。卵泡膜细胞中BMP - 7 mRNA的表达在选择前卵泡和选择后卵泡之间没有差异。在牛有腔卵泡的颗粒细胞中检测到ActRII和ALK - 2的表达，并且选择后卵泡的颗粒细胞中的表达高于选择前卵泡，而卵泡膜细胞中ActRII和ALK - 2基因的表达在选择前卵泡和选择后卵泡之间没有差异。单独用E2（10ng/ml）处理颗粒细胞增加了ActRII和ALK - 2 mRNA的表达，而单独用FSH没有作用。然而，E2（1ng/ml）和FSH（5ng/ml）的组合上调了ActRII和ALK - 2 mRNA的水平。本研究的结果首次提供了证据，表明FSH和E2调节牛颗粒细胞中ActRII和ALK - 2基因的表达。因此，我们的数据表明BMP7/ActRII/ALK - 2系统可能在牛卵泡选择过程中起关键作用。（c）2006爱思唯尔爱尔兰有限公司。保留所有权利。
Bone morphogenetic proteins (BMPs) are crucial factors in follicular growth and development. Among the BMP ligands, BMP-7 which use ActRII as their type II receptor, strongly bind to ALK-2 as their type I receptor. However, whether their receptors are expressed and the regulatory mechanisms controlling their expression during the process of bovine follicle development are still unknown. The aim of the present study was to clarify the involvement of the receptor system for BMP-7 in follicular selection by examining the effects of foillicle-stimulating hormone (FSH) and estradiol (E2) on the regulation of ActRII and ALK-2 mRNA expression in bovine granulosa cells (GCs). To observe mRNA expression, follicles were obtained from heifers and GCs were classified into two groups: pre-selection follicles (PRF; follicles with an average diameter of 7 mm and low E2) and post-selection follicles (POF; follicles with an average diameter of 15 mm and high 132). The theca cell (TC) layer and GCs were harvested from aspirated follicles. For in vitro studies, GCs were obtained from bovine follicles of 4-7 mm diameter and cultured in Dulbecco's modified Eagle's/F12 (DMEM/F-12) medium with 10% fetal calf serum for 24 h. The medium was then replaced with serum-free DMEM/F-12 supplemented with different doses of E2 (1, 10, 100 ng/ml), FSH (1, 5, 10 ng/ml) or combinations of I ng/ml of E2 with different FSH doses (1, 5, 10 ng/ml). Total RNA was extracted from GCs and the mRNA expression of ActRII and ALK-2 was estimated by the quantitative PCR method using LightCycler. The expression of BMP-7 mRNA in TCs did not differ between the PRF and POE ActRII and ALK-2 expression was detected in GCs from bovine antral follicles and was higher in the GCs of POF than in those of PRF, while the expression of the ActRII and ALK-2 genes in the TCs was not different between PRF and POF. Treatment of GCs with E2 (10 ng/ml) alone increased the expression of both ActRII and ALK-2 mRNAs, whereas FSH alone had no effect. However, ActRII and ALK-2 mRNA levels were up-regulated by the combination of E2 (I ng/ml) and FSH (5 ng/ml). The results of the present study provide the first evidence that FSH and E2 regulate the expression of the ActRII and ALK-2 genes in bovine GCs. Thus, our data suggest that the BMP7/ActRII/ALK-2 system may be critically involved in the process of selection of bovine follicles. (c) 2006 Elsevier Ireland Ltd. All rights reserved.