Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Mol Reprod Dev. 2024 Mar;91(3):e23737. doi: 10.1002/mrd.23737.
Extracellular vesicles (EVs) play an important role in the development and function of mammalian ovarian follicles. However, the mechanisms by which they are taken up by the follicular granulosa cells remain unclear. In addition, while oocytes play a pivotal role in follicular development, the possible interactions between oocyte-derived paracrine factors (ODPFs) and EV signals are unknown. Therefore, this study aimed to elucidate the mechanism of EV uptake and the effects of ODPFs on EV uptake by follicular somatic mural granulosa cells in mice. Fluorescence-labeled transferrin (TRF) and cholera toxin B (CTB), substrates for clathrin- and caveolae-mediated endocytosis, respectively, were taken up by mural granulosa cells in vitro. Their uptake was inhibited by Pitstop 2 and genistein, inhibitors of clathrin and caveolae pathways, respectively. Mural granulosa cells took up EVs, and this uptake was suppressed by Pitstop 2 and genistein. Moreover, ODPFs promoted the uptake of EVs and CTB, but not TRF, by mural granulosa cells. These results suggest that mural granulosa cells take up EVs through both clathrin- and caveolae-mediated endocytosis and that oocytes may promote caveolae-mediated endocytosis to facilitate the uptake of EVs.
细胞外囊泡 (EVs) 在哺乳动物卵巢卵泡的发育和功能中发挥着重要作用。然而，它们被卵泡颗粒细胞摄取的机制尚不清楚。此外，虽然卵母细胞在卵泡发育中起着关键作用，但卵母细胞衍生的旁分泌因子 (ODPFs) 和 EV 信号之间的可能相互作用尚不清楚。因此，本研究旨在阐明 EV 摄取的机制以及 ODPFs 对小鼠卵泡体细胞颗粒细胞摄取 EV 的影响。荧光标记的转铁蛋白 (TRF) 和霍乱毒素 B (CTB) 分别是网格蛋白和小窝介导的内吞作用的底物，在体外被颗粒细胞摄取。它们的摄取分别被网格蛋白和小窝途径的抑制剂 Pitstop 2 和金雀异黄素抑制。颗粒细胞摄取了 EVs，而 Pitstop 2 和金雀异黄素抑制了这种摄取。此外，ODPFs 促进了 EV 和 CTB 被颗粒细胞摄取，但不能促进 TRF 的摄取。这些结果表明，颗粒细胞通过网格蛋白和小窝介导的内吞作用摄取 EVs，并且卵母细胞可能促进小窝介导的内吞作用以促进 EV 的摄取。
