Center for Reproductive Medicine and Center for Prenatal Diagnosis, The First Hospital of Jilin University, Changchun, Jilin, China; Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
Cell Signal. 2019 Mar;55:109-118. doi: 10.1016/j.cellsig.2019.01.002. Epub 2019 Jan 8.
Bone morphogenetic protein 6 (BMP6) and transforming growth factor-β1 (TGF-β1) are key intraovarian regulators that play essential roles in regulating mammalian follicular function and promoting oocyte maturation. Furin, a member of the subtilisin-like proprotein convertase family, promotes the activation of diverse functional proteins by cleaving protein precursors in the secretory pathway. The aim of this study was to investigate the effect and underlying molecular mechanisms by which BMP6 regulates the expression of furin to increase TGF-β1 production. Primary and immortalized (SVOG) human granulosa-lutein (hGL) cells were used as study models. Our results show that BMP6 significantly up-regulated the expression of furin and increased the production of TGF-β1 in hGL cells. Using dual inhibition approaches (kinase receptor inhibitors and small interfering RNA-targeted knockdown), we demonstrate that both activin receptor-like (ALK)2 and ALK3 are involved in the BMP6-induced up-regulation of furin. Additionally, knockdown of furin abolished BMP6-induced increases in TGF-β1 production. Moreover, knockdown of endogenous SMAD4 reversed the BMP6-induced increase in furin expression. These results indicate that the ALK2/3-mediated canonical SMAD signaling pathway is required for the stimulatory effect of BMP6 on furin expression, which in turn increases the production of TGF-β1 in hGL cells. Our findings provide insights into the molecular interactions and mechanisms of two intrafollicular growth factors in hGL cells.
骨形态发生蛋白 6（BMP6）和转化生长因子-β1（TGF-β1）是关键的卵巢内调节因子，在调节哺乳动物卵泡功能和促进卵母细胞成熟方面发挥着重要作用。弗林蛋白酶（furin）是枯草杆菌蛋白酶样蛋白前体转化酶家族的成员，通过在分泌途径中切割蛋白前体，促进多种功能蛋白的激活。本研究旨在探讨 BMP6 调节 furin 表达以增加 TGF-β1 产生的作用及其潜在的分子机制。原代和永生化（SVOG）人颗粒黄体（hGL）细胞被用作研究模型。我们的结果表明，BMP6 显著上调 furin 的表达，并增加 hGL 细胞中 TGF-β1 的产生。通过双重抑制方法（激酶受体抑制剂和靶向小干扰 RNA 的敲低），我们证明激活素受体样激酶（ALK）2 和 ALK3 均参与 BMP6 诱导的 furin 上调。此外，敲低 furin 消除了 BMP6 诱导的 TGF-β1 产生增加。此外，敲低内源性 SMAD4 逆转了 BMP6 诱导的 furin 表达增加。这些结果表明，ALK2/3 介导的经典 SMAD 信号通路是 BMP6 对 furin 表达的刺激作用所必需的，这反过来又增加了 hGL 细胞中 TGF-β1 的产生。我们的研究结果为 hGL 细胞中两种卵泡内生长因子的分子相互作用和机制提供了新的见解。
