Han Xiaojuan, Tai Haoran, Wang Xiaobo, Wang Zhe, Zhou Jiao, Wei Xiawei, Ding Yi, Gong Hui, Mo Chunfen, Zhang Jie, Qin Jianqiong, Ma Yuanji, Huang Ning, Xiang Rong, Xiao Hengyi
Lab for Aging Research, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China.
Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.
Aging Cell. 2016 Jun;15(3):416-27. doi: 10.1111/acel.12446. Epub 2016 Feb 18.
AMPK activation is beneficial for cellular homeostasis and senescence prevention. However, the molecular events involved in AMPK activation are not well defined. In this study, we addressed the mechanism underlying the protective effect of AMPK on oxidative stress-induced senescence. The results showed that AMPK was inactivated in senescent cells. However, pharmacological activation of AMPK by metformin and berberine significantly prevented the development of senescence and, accordingly, inhibition of AMPK by Compound C was accelerated. Importantly, AMPK activation prevented hydrogen peroxide-induced impairment of the autophagic flux in senescent cells, evidenced by the decreased p62 degradation, GFP-RFP-LC3 cancellation, and activity of lysosomal hydrolases. We also found that AMPK activation restored the NAD(+) levels in the senescent cells via a mechanism involving mostly the salvage pathway for NAD(+) synthesis. In addition, the mechanistic relationship of autophagic flux and NAD(+) synthesis and the involvement of mTOR and Sirt1 activities were assessed. In summary, our results suggest that AMPK prevents oxidative stress-induced senescence by improving autophagic flux and NAD(+) homeostasis. This study provides a new insight for exploring the mechanisms of aging, autophagy and NAD(+) homeostasis, and it is also valuable in the development of innovative strategies to combat aging.
AMPK激活有利于细胞稳态和衰老预防。然而，参与AMPK激活的分子事件尚未明确界定。在本研究中，我们探讨了AMPK对氧化应激诱导的衰老具有保护作用的潜在机制。结果显示，衰老细胞中的AMPK失活。然而，二甲双胍和小檗碱对AMPK的药理学激活显著预防了衰老的发生，相应地，化合物C对AMPK的抑制作用则加速了衰老。重要的是，AMPK激活可预防过氧化氢诱导的衰老细胞自噬流受损，这可通过p62降解减少、GFP-RFP-LC3荧光消失以及溶酶体水解酶活性得以证明。我们还发现，AMPK激活通过主要涉及NAD⁺合成补救途径的机制恢复了衰老细胞中的NAD⁺水平。此外，还评估了自噬流与NAD⁺合成的机制关系以及mTOR和Sirt1活性的参与情况。总之，我们的结果表明，AMPK通过改善自噬流和NAD⁺稳态来预防氧化应激诱导的衰老。本研究为探索衰老、自噬和NAD⁺稳态的机制提供了新的见解，并且在开发对抗衰老的创新策略方面也具有重要价值。
