Center for Reproductive Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Henan Key Laboratory of Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
J Ovarian Res. 2023 Aug 26;16(1):175. doi: 10.1186/s13048-023-01258-3.
Follicular development in mammalian ovaries is a complex and dynamic process, and the interactions and regulatory-feedback loop between the follicular microenvironment, granulosa cells (GCs), and oocytes can affect follicular development and normal ovary functions. Abnormalities in any part of the process may cause abnormal follicular development, resulting in infertility. Hence, exploring the pathogenesis of abnormal follicular development is extremely important for diagnosing and treating infertile women.
RNA sequencing was performed with ovarian cortical tissues established in vitro. In situ-hybridization assays were performed to study microRNA-338-3p (miR-338-3p) expressed in GCs and oocytes. In vitro culture models were established with GCs and neonatal mouse ovaries to study the biological effects of miR-338-3p. We also performed in vivo experiments by injecting adeno-associated virus vectors that drive miR-338-3p overexpression into the mouse ovarian bursae.
Sequencing analysis showed that miR-338-3p was expressed at significantly higher levels in ovarian cortical tissues derived from patients with ovarian insufficiency than in cortical tissues derived from patients with normal ovarian function; miR-338-3p was also significantly highly expressed in the GCs of patients with diminished ovarian reserve (P < 0.05). In situ-hybridization assays revealed that miR-338-3p was expressed in the cytoplasm of GCs and oocytes. Using in vitro culture models of granulosa cells, we found that miR-338-3p overexpression significantly suppressed the proliferation and oestradiol-production capacity of GCs (P < 0.05). In vitro culture models of neonatal mouse ovaries indicated that miR-338-3p overexpression suppressed the early follicular development in mouse ovaries. Further analysis revealed that miR-338-3p might be involved in transforming growth factor β-dependent regulation of granulosa cell proliferation and, thus, early follicular development. Injecting miR-338-3p-overexpression vectors into the mouse ovarian bursae showed that miR-338-3p down-regulated the oocyte mitochondrial membrane potential in mice and disrupted mouse oestrous cycles.
miR-338-3p can affect early follicular development and normal ovary functions by interfering with the proliferation and oestradiol production of GCs. We systematically elucidated the regulatory effect of miR-338-3p on follicular development and the underlying mechanism, which can inspire new studies on the diagnosis and treatment of diseases associated with follicular development abnormalities.
哺乳动物卵巢中的卵泡发育是一个复杂而动态的过程，卵泡微环境、颗粒细胞（GCs）和卵母细胞之间的相互作用和调控反馈环可以影响卵泡发育和正常卵巢功能。该过程任何部分的异常都可能导致卵泡发育异常，从而导致不孕。因此，探索异常卵泡发育的发病机制对于诊断和治疗不孕妇女极为重要。
对体外建立的卵巢皮质组织进行 RNA 测序。进行原位杂交检测以研究 GCs 和卵母细胞中表达的 microRNA-338-3p（miR-338-3p）。建立 GCs 和新生小鼠卵巢的体外培养模型，以研究 miR-338-3p 的生物学效应。我们还通过向小鼠卵巢囊腔内注射驱动 miR-338-3p 过表达的腺相关病毒载体，进行体内实验。
测序分析表明，卵巢功能不全患者的卵巢皮质组织中 miR-338-3p 的表达水平明显高于卵巢功能正常患者的皮质组织；储备功能减退患者的 GCs 中 miR-338-3p 的表达也明显升高（P<0.05）。原位杂交检测显示，miR-338-3p 表达在 GCs 和卵母细胞的细胞质中。通过体外培养的颗粒细胞模型，我们发现 miR-338-3p 过表达显著抑制了 GCs 的增殖和雌二醇产生能力（P<0.05）。新生小鼠卵巢的体外培养模型表明，miR-338-3p 过表达抑制了小鼠卵巢中的早期卵泡发育。进一步分析表明，miR-338-3p 可能参与转化生长因子 β 依赖的 GC 增殖和早期卵泡发育的调控。向小鼠卵巢囊腔内注射 miR-338-3p 过表达载体，发现 miR-338-3p 下调了小鼠卵母细胞的线粒体膜电位并破坏了小鼠动情周期。
miR-338-3p 通过干扰 GCs 的增殖和雌二醇产生，影响早期卵泡发育和正常卵巢功能。我们系统地阐明了 miR-338-3p 对卵泡发育的调节作用及其潜在机制，这可以为与卵泡发育异常相关疾病的诊断和治疗提供新的研究思路。
