THE ROLE OF COMMUNICATIONS AMONG THE OVARIAN CELLS IN EARLY STAGE OF THE FOLLICULAR DEVELOPMENT AND ATRESIA

我们研究了卵泡发育早期颗粒细胞(GC)、卵泡膜细胞(TC)和卵母细胞之间的细胞通讯在卵泡成熟和闭锁中的作用。TC促进GC芳香酶mRNA的表达，导致雌二醇的产生增加。TC不改变P450scc、3-β-HSD、LHR和STAR在GC中孕酮的产生和基因表达。结果表明，TC参与了雌激素产生的两个限速步骤，即雄激素底物的产生和芳香化酶的调节，TC衍生的因子以一种反映类固醇生成的方式调节雌二醇和孕酮的产生。在研究的第二部分，我们验证了基质细胞(SC)在卵泡发育早期分化为TC的假说，这一过程涉及与GC的相互作用。GC可增加SC中脂滴和线粒体的数量，刺激雄烯二酮的产生和黄体生成素受体mRNA的表达，提示GC参与了间质细胞对黄体生成素反应性的功能分化和获得。最后，研究了卵母细胞衍生生长分化因子-9(GDF-9)对颗粒和膜细胞功能的调控。我们发现GDF-9通过激活PI3K/Akt通路和FSH受体mRNA在GC中的表达来保护颗粒细胞的凋亡。

We have studied the role of cellular communication among the granulosa cell (GC) theca cell (TC) and oocyte in follicular maturation and atresia during the early stage of the development.In the first part of the study, we investigated the effects of TC on GC differentiation and steroid production. TC enhanced aromatase mRNA expression in GC resulting in an increase in estradiol production. TC did not alter progesterone production and mRNA expression in GC for P450scc, 3β-HSD, LHr, and StAR. The results indicate that TC are involved in both rate-limiting steps in estrogen production; i.e., androgen substrate production and aromatase regulation, and that TC-derived factors regulate estradiol and progesterone production in a way that reflects steroidogenesis.In the second part of the study, we have examined the hypothesis that stromal cells (SC) differentiate into TC during early follicular development and that this process involves the interaction with GC. GC increased the number of lipid droplets and mitochondria, and stimulated androstenedione production and LH receptor mRNA expression in SC, suggested that GC are involved in the functional differentiation of and acquisition of LH responsiveness in stromal cells.In the last study, how oocyte-derived growth differentiation factor-9 (GDF-9) controls granulose and theca cell function. We found that GDF-9 protects granulosa cells from undergoing apoptosis via activation of the PI3K/Akt pathway and FSH receptor mRNA expression in GC.