SIRT1-SIRT6信号通路在能量限制延长卵巢寿命中的调控机制

Human lifespan has been gradually prolonging since last century.However,the average age of menopause for women is relatively stable at 51 years. Calorie restriction (CR)extends lifespan of many species of animals, and also extends lifespan of mammalian ovary. It is well known that SIRT1 (or sirtuins 1)plays a pivotal role in CR mechanism. But the mechanism of CR extending the ovarian lifespan is largely unknown. Our results of previous studies suggest that SIRT1,SIRT6 and FOXO3a factors may be involved in the mechanisms of CR extending ovarian lifespan. In the light of our studies and recent reports, we presume that SIRT1/FOXO3a/NRF1-SIRT6 signaling may play an important role in the mechanism of CR extending ovarian lifespan. Therefore, in this proposal we will prepare CR mouse model, SIRT1 and SIRT6 transgenic mice and investigate the development of ovarian follicles and the ovarian lifespan after up-regulating SIRT1 and SIRT6 in transgenic mice comparing with CR mice. We wil also use RNAi techniques and SIRT inhibitors in vivo, and investigate the relationship of this pathway with CR and ovarian lifespan extension, and further verify whether SIRT1/FOXO3a/NRF1-SIRT6 signaling play an role in ovarian lifespan. We will also examine the expression and activity of target genes down-stream this pathway, and investigate the mechanism of this pathway in regulating ovarian lifespan extension. Our study will provide new insight into the mechanism of CR extending ovarian lifespan and also into the potential therapeutic targets.

人类文明进步使寿命不断延长，但女性的闭经年龄却相对恒定。能量限制(CR)延长各种动物的寿命，也使哺乳类卵巢寿命延长。已知SIRT1是调控CR延长动物寿命的关键因子，但CR延长卵巢寿命的机制仍不清楚。本团队前期研究结果提示SIRT1、SIERT6和FOXO3a等因子可能参与卵巢寿命调控，结合近期研究我们推测SIRT1/FOXO3a/NRF1-SIRT6信号通路可能在CR延长卵巢寿命的机制中发挥重要调控作用。本课题拟用CR小鼠模型和SIRT1、SIRT6转基因小鼠,对比观察CR和该信号通路对卵泡发育和卵巢寿命的影响；再用体内RNA干扰技术和SIRT抑制剂下调SIRT1和SIRT6的表达及活性，进一步验证该信号通路对卵泡发育及卵巢寿命的影响，从而验证我们的推测；同时通过检测其下游靶分子深入研究其调控机制，为探讨CR延长卵巢寿命的机制提供新的研究思路，为延缓女性闭经,延长卵巢寿命提供可干预靶点。

能量限制（CR）延长各种动物的寿命，也使哺乳类卵巢寿命延长。已知SIRT1是调控CR延长动物寿命的关键因子，但CR延长卵巢寿命的机制仍不清楚。我们根据前期工作提出SIRT1/FOXO3a/NRF1-SIRT6信号通路可能在CR延长卵巢寿命的机制中发挥重要调控作用的假说。本课题旨在验证我们的假说，同时探讨CR延长卵巢寿命的分子调控机制。.首先我们建立了CR和肥胖大鼠及小鼠动物模型，对比研究结果表明CR可使大鼠和小鼠卵巢内SIRT1/FOXO3a/NRF1-SIRT6信号上调，同时也发现mTOR/pS6K信号下调，而在肥胖动物体内却正好相反；CR抑制卵巢内原始卵泡的发育启动和各级卵泡的发育以及卵泡的凋亡，从而维持成年鼠和老年鼠的卵泡储备，延长卵巢的寿命，而肥胖正相反。我们又用SIRT1激活剂和mTOR抑制剂分别激活SIRT1信号和抑制mTOR信号通路，结果表明：激活SIRT1信号同时使mTOR信号上调，抑制mTOR信号也同时使SIRT1信号上调，均可使鼠类卵巢寿命延长，说明SIRT1和mTOR信号通路间存在相互作用关系。这些结果充分支持我们的假说。SIRT1转基因小鼠研究结果表明SIRT1在小鼠卵巢内特异高表达不影响原始卵泡池的形成，即对原始卵泡池的大小没有显著影响，但可减缓卵泡的发育速率，从而使转基因小鼠的性成熟推迟，使成年鼠和老年鼠的卵泡储备增加，因此使卵巢的寿命延长。转基因小鼠实验也再次证明了SIRT1在卵巢内高表达可抑制mTOR信号通路的调控机制。转基因小鼠实验结果再次验证了我们的假说。.我们的结论是：能量限制通过激活卵巢内SIRT1/FOXO3a/NRF1-SIRT6信号通路和下调mTOR/pS6K信号通路抑制原始卵泡的发育启动和各级卵泡的发育速率，同时也抑制各级卵泡的凋亡，减少卵泡的丢失，因而维持卵泡的储备，延长卵巢的寿命。本研究为CR延长卵巢寿命提供了新的分子机制，为防治肥胖等因素可能引起的卵巢早衰提供了可干预的分子靶点。本成果也对女性推迟更年期，提高高龄女性的生活质量有重要的指导作用。