Developmental and hormonal regulation of keratinocyte growth factor expression and action in the ovarian follicle
Developmental and hormonal regulation of keratinocyte growth factor expression and action in the ovarian follicle
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DOI：
10.1210/en.139.1.228
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发表时间：
1998-01-01
期刊：
影响因子：
4.8
通讯作者：
Skinner, MK
中科院分区：
文献类型：
--
作者：
Parrott, JA;Skinner, MK
发育中的卵泡是体内增殖最快的正常组织之一。卵泡膜细胞和颗粒细胞之间的间充质-上皮细胞相互作用是卵泡扩张的关键。卵巢激素（即雌激素和LH）可通过调节介导卵泡膜细胞-颗粒细胞相互作用的间充质诱导蛋白的局部产生来促进卵泡发育。最近，卵泡膜细胞被证明可以产生角质细胞生长因子（KGF），它可以以旁分泌的方式刺激颗粒细胞的生长。在这项研究中，发育和激素调节KGF在牛卵巢卵泡发育过程中进行了检查。使用RT-PCR检测了卵泡膜细胞中KGF的表达和颗粒细胞中KGF受体（KGFR，或成纤维细胞生长因子家族受体家族的剪接变体，FGFR-2）的表达。在小卵泡（10 mm）的整个卵泡发育过程中检测到KGF和KGFR。定量RT-PCR测定用于确定KGF和KGFR信使RNA的稳态水平。在新鲜分离的卵泡膜细胞和颗粒细胞中分析了KGF和KGFR的发育调控，这些细胞来自小、中、大卵泡。观察结果表明，KGF（在卵泡膜细胞中）和KGFR（在颗粒细胞中）的表达在大卵泡中最高。这些结果表明，KGF的行动是重要的颗粒细胞在大卵泡的快速增殖。雌激素和LH是体内调节卵泡膜细胞功能的主要内分泌激素。因此，通过用雌激素和人CG（hCG，LH激动剂）处理无血清卵泡膜细胞培养物来分析KGF的激素调节。结果表明，雌激素和hCG均能刺激卵泡膜细胞KGF基因的表达。这些结果表明，雌激素和LH可能促进卵泡生长（即颗粒细胞增殖），部分是通过刺激KGF的局部生产。观察KGF对颗粒细胞分化功能的影响。KGF治疗降低了牛和大鼠颗粒细胞芳香化酶活性的基础水平和FSH刺激水平。此外，KGF抑制hCG刺激颗粒细胞产生孕酮的能力。KGF抑制颗粒细胞分泌类固醇激素可能是促进细胞增殖的间接作用。因此，KGF直接刺激颗粒细胞增殖并间接抑制颗粒细胞分化功能。综合结果表明，卵泡膜细胞生产的KGF可能是重要的卵泡发生。这是首次报道卵巢中KGF表达的调控。卵泡发生过程中KGF和KGFR的发育和激素调节提供了证据，KGF可能是重要的卵泡诱导的颗粒细胞增殖。因此，KGF可能是建立卵巢卵母细胞成熟所需的微环境所必需的。
The developing ovarian follicle is one of the most rapidly proliferating normal tissues in vivo. Mesenchylmal-epithelial cell interactions between theca cells and granulosa cells are essential for this follicular expansion. Ovarian hormones (i.e. estrogen and LH) may promote follicular development by regulating the local production of mesenchymal inducer proteins that mediate theca cell-granulosa cell interactions. Recently, theca cells were shown to produce keratinocyte growth factor (KGF) that can act in a paracrine manner to stimulate granulosa cell growth. In this study, the developmental and hormonal regulation of KGF was examined during follicular development in the bovine ovary. Expression of KGF in theca cells and the KGF receptor (KGFR, or splice variant of the fibroblast growth factor family receptor family, FGFR-2) in granulosa cells was examined using RT-PCR. Both KGF and KGFR were detected throughout follicular development in small (10 mm) follicles. Quantitative RT-PCR assays were used to determine steady-state levels of KGF and KGFR messenger RNAs. Developmental regulation of KGF and KGFR was analyzed in freshly isolated theca cells and granulosa cells from small, medium, and large follicles. Observations demonstrated that expression of KGF (in theca cells) and KGFR (in granulosa cells) was highest in large follicles. These results suggest that KGF actions are important for the rapid proliferation of granulosa cells in large follicles. Estrogen and LH are the primary endocrine hormones that regulate theca cell function in vivo. Therefore, hormonal regulation of KGF was analyzed by treating serum-free theca cell cultures with estrogen and human CG (hCG, an LH agonist). Results showed that both estrogen and hCG stimulated KGF gene expression in theca cells. These results suggest that estrogen and LH may promote follicular growth (i.e. granulosa cell proliferation), in part, by stimulating the local production of KGF. Effects of KGF on granulosa cell differentiated functions were examined. Treatment with KGF reduced basal levels and FSH-stimulated levels of aromatase activity in bovine and rat granulosa cells. In addition, KGF inhibited the ability of hCG to stimulate progesterone production by granulosa cells. The inhibition of granulosa cell steroid production by KGF was likely the indirect effect of promoting cellular proliferation. Therefore, KGF directly stimulates granulosa cell proliferation and indirectly inhibits granulosa cell differentiated functions. Combined results suggest that theca cell production of KGF may be important for ovarian folliculogenesis. This is the first report of the regulation of KGF expression in the ovary. The developmental and hormonal regulation of KGF and KGFR during folliculogenesis provides evidence that KGF may be important for hormone-induced granulosa cell proliferation. As a result, KGF may be essential for establishing the microenvironment required for oocyte maturation in the ovary.