昼夜时钟蛋白NR1D1通过调节线粒体生物合成和脂质运输来控制颗粒细胞内分泌功能. 昼夜时钟蛋白NR1D1通过调节线粒体生物合成和脂质运输来控制颗粒细胞内分泌功能

With rapid economic and social development, people's living habits have changed dramatically. Long-term exposure to artificial light, shift work and staying up late have been found to seriously disrupt people's normal biological rhythms and impair female reproductive function, leading to increased rates of infertility and abortion. In this study, we established a mouse model of continuous light exposure to explore the effects of long-term environmental circadian disturbances on the reproductive endocrine function and related mechanisms in females. We found that continuous light exposure caused reproductive and endocrine metabolic abnormalities in female mice, including estrous cycle disorders, ovarian changes of increased unruptured luteinized cystic follicles, LH elevation and hyperandrogenism. Moreover, the circadian rhythm genes expression in follicular granulosa cells was disrupted, in particular the expression of Nr1d1 showed a significant increase at night. We further showed that the up-regulation of NR1D1 promoted the expression of mitochondrial biosynthesis protein PGC1α and lipid transport related proteins such as SLC27A6, CPT1α, etc, in granulosa cells, and activated the PTEN/PI3K/AKT signaling pathway, leading to premature luteinization of granulosa cells. In addition, the gap junctions between cumulus and oocytes were prematurely closed in COCs treated with NR1D1 agonist GSK4112, which impaired oocyte quality, resulting in reduced maturation, disordered spindle assembly and chromosome arrangement, mitochondrial dysfunction. In conclusion, the circadian clock protein NR1D1 plays an essential role in maintaining granulosa cell endocrine function and oocyte quality. The findings may provide fresh insights into how circadian rhythm disturbances caused by staying up late and continuous exposure to artificial light sources can damage female reproductive function. Overall design: To further investigate how elevated expression levels of NR1D1 are involved in affecting endocrine function in granulosa cells, we selected the NR1D1 agonist GSK4112 to treat follicular granulosa cells of female mice in vivo.

随着经济社会的快速发展，民众的生活习惯发生了显著改变。研究显示，长期暴露于人工光照、倒班工作以及熬夜，会严重扰乱人体正常昼夜节律（circadian rhythm），损伤女性生殖功能，进而导致不孕症与流产发生率升高。
本研究构建了持续光照暴露小鼠模型，旨在探究长期环境昼夜节律紊乱对雌性个体生殖内分泌功能的影响及其相关作用机制。研究发现，持续光照暴露会引发雌性小鼠出现生殖内分泌代谢异常，具体表现为动情周期紊乱、卵巢内未破裂黄素化囊性卵泡增多、黄体生成素（Luteinizing Hormone, LH）水平升高以及高雄激素血症。此外，卵泡颗粒细胞（follicular granulosa cells）中的昼夜节律基因表达谱发生紊乱，其中Nr1d1基因在夜间的表达量显著升高。进一步研究显示，NR1D1的上调会促进颗粒细胞中线粒体生物合成蛋白PGC1α以及脂质转运相关蛋白（如SLC27A6、CPT1α等）的表达，并激活PTEN/PI3K/AKT信号通路，最终导致颗粒细胞过早黄素化。此外，经NR1D1激动剂GSK4112处理的卵丘-卵母细胞复合体（cumulus-oocyte complex, COCs）中，卵丘细胞与卵母细胞间的间隙连接提前闭合，进而损伤卵母细胞质量，表现为成熟率降低、纺锤体组装与染色体排列紊乱以及线粒体功能异常。综上，昼夜节律钟蛋白NR1D1在维持颗粒细胞内分泌功能与卵母细胞质量方面发挥关键作用。本研究结果可为阐明熬夜与持续暴露于人工光源引发的昼夜节律紊乱如何损伤女性生殖功能提供新的研究视角。
实验整体设计：为进一步探究NR1D1表达上调如何参与调控颗粒细胞内分泌功能，本研究选用NR1D1激动剂GSK4112，对雌性小鼠体内的卵泡颗粒细胞进行干预处理。