Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, PR China; NHC Key Laboratory of study on abnormal gametes and reproductive tract, Anhui Medical University, Hefei 230022, PR China; Department of Histology and Embryology, Anhui Medical University, Hefei 230032, Anhui, PR China.
Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, PR China; NHC Key Laboratory of study on abnormal gametes and reproductive tract, Anhui Medical University, Hefei 230022, PR China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, PR China; Anhui Province Key Laboratory of Reproductive Health and Genetics, No 81 Meishan Road, Hefei 230032, Anhui, PR China; Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, PR China; Anhui Provincial Institute of Translational Medicine, No 81 Meishan Road, Hefei 230032, Anhui, PR China.
Mitochondrion. 2021 Nov;61:44-53. doi: 10.1016/j.mito.2021.09.009. Epub 2021 Sep 24.
Excessive autophagy-induced follicular atresia of ovarian granulosa cells might be one of the pathogenesis of Premature Ovarian Insufficiency (POI), and melatonin (MT) exerted many beneficial effects on mitochondria. However, there was little report regarding the beneficial effects of MT on excessive autophagy-induced mitochondrial and ovarian reserve function deficiency, and the mechanisms have not been clearly identified. Autophagy played a protective role in cells survival, however, high level of autophagy could lead to cell death. In this report, firstly, Chinese hamster ovary cell damage model stably expressing EGFP-LC3 was established. Next, we systematically investigated the protective effects of MT on mitochondrial and ovarian reserve function and molecular mechanisms using this cell damage model. Our results revealed that 10 M MT not only protected against the decline of anti-mullerian hormone (AMH) expression induced by excessive autophagy, but also rescued excessive autophagy-induced impairment of mitochondrial expression and mitochondrial membrane potential. Furthermore, MT protected against excessive autophagy-induced decrease of nucleus-encoded proteins including SDHA and mitofilin, and mitochondrial dynamic-related proteins including OPA1, MFN2, and DRP1. MT also decreased mitochondrial oxidative stress, increased antioxidant enzyme superoxide dismutase 2 (SOD2) expression and ameliorated the G2/M cell cycle arrest induced by excessive autophagy. Finally, MT inhibited excessive autophagy-induced activation of extracellular signal regulated kinase (ERK) signaling pathway. In conclusion, our study showed that MT rescued impairment of mitochondrial and ovarian reserve function, and production of mitochondrial ROS and cell cycle arrest induced by excessive autophagy through down-regulated ERK pathway, implying the potential therapeutic drug target for POI.
过度的自噬诱导卵巢颗粒细胞卵泡闭锁可能是卵巢早衰（POI）的发病机制之一，而褪黑素（MT）对线粒体发挥了许多有益作用。然而，关于 MT 对过度自噬诱导的线粒体和卵巢储备功能缺陷的有益作用的报道很少，其机制也尚未明确。自噬在细胞存活中发挥保护作用，然而，高水平的自噬可能导致细胞死亡。在本报告中，首先建立了稳定表达 EGFP-LC3 的中国仓鼠卵巢细胞损伤模型。接下来，我们使用该细胞损伤模型系统地研究了 MT 对线粒体和卵巢储备功能的保护作用及其分子机制。我们的结果表明，10 μM MT 不仅可以防止过度自噬诱导的抗苗勒管激素（AMH）表达下降，还可以挽救过度自噬诱导的线粒体表达和线粒体膜电位损伤。此外，MT 可以防止过度自噬诱导的核编码蛋白（包括 SDHA 和 mitofilin）和线粒体动力学相关蛋白（包括 OPA1、MFN2 和 DRP1）的减少。MT 还可以减少线粒体氧化应激，增加抗氧化酶超氧化物歧化酶 2（SOD2）的表达，并改善过度自噬诱导的 G2/M 细胞周期停滞。最后，MT 抑制了过度自噬诱导的细胞外信号调节激酶（ERK）信号通路的激活。总之，我们的研究表明，MT 通过下调 ERK 信号通路，挽救了过度自噬诱导的线粒体和卵巢储备功能损伤、线粒体 ROS 产生和细胞周期停滞，这为 POI 提供了潜在的治疗药物靶点。
