Li Jinqiu, Luo Wei, Huang Tao, Gong Yanzhang
Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Gen Comp Endocrinol. 2019 May 15;276:69-76. doi: 10.1016/j.ygcen.2019.03.005. Epub 2019 Mar 6.
The function of oocyte-derived growth differentiation factor 9 (GDF9) in ovarian follicles has thus far been poorly defined in avian species compared with the defined function in mammals. Our aim here is to investigate the effects of GDF9 on steroidogenesis and on chicken ovarian granulosa cell (GC) mitosis. Primary GCs from both prehierarchical (6-8 mm in diameter, phGCs) and preovulatory follicles (F1-F5, poGCs) were cultured in the presence or absence of the GDF9 protein. The progesterone (P4) levels in the culture medium were then measured by radioimmunoassay (RIA), and the expression levels of steroidogenesis genes were detected by quantitative PCR. We found that GDF9 alone showed no significant effect on the P4 levels by regulating the expression of steroidogenesis genes, such as STAR, CYP11A1 and HSD3B. Further experiments indicated that GDF9 promoted follicle-stimulating hormone (FSH)-induced P4 production and STAR expression. GDF9 also rescued the FSH-induced decrease of FSH receptor (FSHR) expression but had no effect on the forskolin-induced P4, STAR and forskolin-inhibited FSHR expression levels, suggesting that GDF9 might achieve its regulatory role of P4 by enhancing FSHR and STAR expression. In addition, GDF9 also promoted GC cell cycle progression, regulated the gene transcription of related genes, potentiated DNA replication and inhibited apoptosis. Interestingly, these effects differed between the phGCs and the poGCs. To our knowledge, this is the first report that illustrates the function of GDF9 on chicken GCs and the effects on ovarian steroidogenesis. Our findings highlight the regulation of central oocytes on the surrounding granulosa cells and emphasize the interaction between paracrine signals and endocrine hormones on ovarian progesterone production; these findings contribute to the understanding of the development of avian ovarian follicles.
与在哺乳动物中已明确的功能相比，卵母细胞衍生的生长分化因子9（GDF9）在禽类卵泡中的功能迄今尚未明确界定。我们在此的目的是研究GDF9对类固醇生成和鸡卵巢颗粒细胞（GC）有丝分裂的影响。来自分级前卵泡（直径6 - 8毫米，phGCs）和排卵前卵泡（F1 - F5，poGCs）的原代GC在有或没有GDF9蛋白的情况下进行培养。然后通过放射免疫分析（RIA）测量培养基中的孕酮（P4）水平，并通过定量PCR检测类固醇生成基因的表达水平。我们发现，单独的GDF9通过调节类固醇生成基因（如STAR、CYP11A1和HSD3B）的表达对P4水平没有显著影响。进一步的实验表明，GDF9促进促卵泡激素（FSH）诱导的P4产生和STAR表达。GDF9还挽救了FSH诱导的促卵泡激素受体（FSHR）表达的降低，但对福斯可林诱导的P4、STAR和福斯可林抑制的FSHR表达水平没有影响，这表明GDF9可能通过增强FSHR和STAR表达来实现其对P4的调节作用。此外，GDF9还促进GC细胞周期进程，调节相关基因的基因转录，增强DNA复制并抑制细胞凋亡。有趣的是，这些作用在phGCs和poGCs之间有所不同。据我们所知，这是第一份阐述GDF9对鸡GCs的功能以及对卵巢类固醇生成影响的报告。我们的研究结果突出了中央卵母细胞对周围颗粒细胞的调节作用，并强调了旁分泌信号与内分泌激素在卵巢孕酮产生上的相互作用；这些发现有助于理解禽类卵巢卵泡的发育。
