SIRT6蛋白调控器官及细胞衰老机制研究

发布时间：2018-05-19 22:20

本文选题：SIRT6 + 热量限制　；参考：《清华大学》2016年博士论文

【摘要】：热量限制的延寿功能从酵母、线虫到哺乳动物都有明显效果,而沉默信息调节因子家族蛋白SIRT6在热量限制介导的延寿过程中发挥重要作用。核转录因子NF-κB参与到炎症、免疫应答、衰老和凋亡的调控过程中,而NF-κB信号通路的活性与SIRT6蛋白密切相关。在本研究中,我们探究了SIRT6蛋白调控衰老、炎症及凋亡的作用效果并探讨其作用机制。在本论文中,我们将24月龄小鼠在热量限制的条件下饲养30月龄。研究结果显示,热量限制可以有效改善老年小鼠肾脏病理表征并提高SIRT6蛋白的表达水平。此外,我们通过低糖培养成纤维二倍体细胞WI38的方式体外模拟热量限制的作用效果,研究结果证实这种模拟热量限制的细胞培养方式可以有效延缓细胞衰老。此外,SIRT6过表达可以抵抗细胞的复制衰老并抑制NF-κB信号通路活性;而SIRT6的敲低会促进细胞衰老并激活NF-κB信号通路。此外,有研究报道SIRT6具有癌症抑制因子的潜能,并且NF-κB信号通路的激活会导致细胞凋亡抵抗。因此,我们在宫颈癌细胞Hela中过表达或敲低SIRT6蛋白,检测SIRT6表达水平改变对于癌细胞凋亡的影响并检测NF-κB信号通路的活性。结果显示,SIRT6过表达会抑制NF-κB的转录活性,提高癌细胞对于凋亡诱导剂的敏感程度进而提高癌细胞凋亡率;而SIRT6敲低会提高NF-κB的转录活性,引起凋亡抵抗从而降低癌细胞的凋亡率。在此基础上,我们希望寻找模拟热量限制的有效方法。植物提取物白藜芦醇能够通过发挥抗氧化、心脏保护及抗癌等作用而改善衰老,但其是否能够模拟热量限制的作用效果尚不明确。通过细胞实验,我们发现白藜芦醇可以有效缓解高糖培养引起的细胞衰老,并提高细胞的抗氧化能力。并且,在动物实验中我们发现,白藜芦醇可以抵抗由高脂饮食引起的小鼠肾脏病理损伤。尽管白藜芦醇对于SIRT6的表达水平没有显著影响,但可以激活Sirtuin家族的另一个关键蛋白SIRT1。综上所述,本研究证实SIRT6在热量限制介导的延寿过程中发挥重要作用,并初步证实其作为癌症抑制因子的可能性,在此基础上提出了体外模拟热量限制、激活Sirtuin家族蛋白的方法,为实现健康衰老提供研究基础。
[Abstract]:The function of caloric restriction is from yeast, nematode to mammal, and silencing information regulation factor family protein SIRT6 plays an important role in caloric restriction mediated life prolongation. Nuclear transcription factor NF- 魏 B is involved in the regulation of inflammation, immune response, aging and apoptosis, and the activity of NF- 魏 B signaling pathway is closely related to SIRT6 protein. In this study, we investigated the effects of SIRT6 protein on aging, inflammation and apoptosis. In this study, 24-month-old mice were fed 30 months of age under caloric restriction. The results showed that caloric restriction could effectively improve the renal pathological features and the expression of SIRT6 protein in aged mice. In addition, we simulated the effect of caloric restriction by low glucose culture of fibrodiploid cells WI38 in vitro. The results showed that the simulated caloric restriction could effectively delay cell senescence. In addition, the overexpression of sirt6 could resist the replication and senescence of cells and inhibit the activity of NF- 魏 B signaling pathway, while the knockout of SIRT6 could promote cell senescence and activate NF- 魏 B signaling pathway. In addition, it has been reported that SIRT6 has the potential of cancer suppressor, and the activation of NF- 魏 B signaling pathway leads to apoptosis resistance. Therefore, we overexpressed or knocked down the SIRT6 protein in Hela of cervical cancer cells, detected the effect of changes in SIRT6 expression level on the apoptosis of cancer cells and detected the activity of NF- 魏 B signaling pathway. The results showed that overexpression of sirt6 inhibited the transcription activity of NF- 魏 B, increased the sensitivity of cancer cells to apoptosis inducers and increased the apoptosis rate of cancer cells, while SIRT6 knockdown increased the transcription activity of NF- 魏 B. It causes resistance to apoptosis and thus reduces the rate of apoptosis of cancer cells. On this basis, we hope to find an effective method to simulate the heat limitation. Resveratrol can improve senescence by exerting antioxidant, heart protection and anticancer effects, but it is not clear whether resveratrol can mimic the effect of caloric restriction. Through cell experiments, we found that resveratrol can effectively alleviate the aging of cells induced by high glucose culture, and improve the antioxidant ability of cells. Moreover, in animal experiments, resveratrol can resist kidney pathological damage induced by high-fat diet in mice. Although resveratrol has no significant effect on the expression of SIRT6, it activates another key protein in the Sirtuin family, SIRT1. In conclusion, this study confirmed that SIRT6 plays an important role in caloric restriction mediated life prolongation, and preliminarily confirmed the possibility of SIRT6 as a cancer suppressor. On the basis of this, a simulated caloric restriction in vitro was proposed. The method of activating Sirtuin family proteins provides a basis for healthy aging.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R363

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