Wang Fang, Wang Ke, Xu Wei, Zhao Shimin, Ye Dan, Wang Yi, Xu Ying, Zhou Lisha, Chu Yiwei, Zhang Cuiping, Qin Xue, Yang Pengyuan, Yu Hongxiu
Department of Systems Biology for Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China; Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China.
Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China.
Cell Rep. 2017 Jun 13;19(11):2331-2344. doi: 10.1016/j.celrep.2017.05.065.
LPS-activated macrophages undergo a metabolic shift from dependence on mitochondria-produced ATP to reliance on aerobic glycolysis, where PKM2 is a critical determinant. Here, we show that PKM2 is a physiological substrate of SIRT5 and that SIRT5-regulated hypersuccinylation inhibits the pyruvate kinase activity of PKM2 by promoting its tetramer-to-dimer transition. Moreover, a succinylation-mimetic PKM2 K311E mutation promotes nuclear accumulation and increases protein kinase activity. Furthermore, we show that SIRT5-dependent succinylation promotes PKM2 entry into nucleus, where a complex of PKM2-HIF1α is formed at the promoter of IL-1β gene in LPS-stimulated macrophages. Activation of PKM2 using TEPP-46 attenuates Sirt5-deficiency-mediated IL-1β upregulation in LPS-stimulated macrophages. Finally, we find that Sirt5-deficient mice are more susceptible to DSS-induced colitis, which is associated with Sirt5 deficiency prompted PKM2 hypersuccinylation and boosted IL-1β production. In conclusion, our findings reveal a mechanism by which SIRT5 suppresses the pro-inflammatory response in macrophages at least in part by regulating PKM2 succinylation, activity, and function.
脂多糖激活的巨噬细胞会经历代谢转变，从依赖线粒体产生的三磷酸腺苷（ATP）转变为依赖有氧糖酵解，其中丙酮酸激酶M2（PKM2）是一个关键决定因素。在此，我们表明PKM2是沉默调节蛋白5（SIRT5）的生理底物，且SIRT5调节的高琥珀酰化通过促进PKM2从四聚体向二聚体的转变来抑制其丙酮酸激酶活性。此外，模拟琥珀酰化的PKM2 K311E突变促进核积累并增加蛋白激酶活性。此外，我们表明SIRT5依赖性琥珀酰化促进PKM2进入细胞核，在脂多糖刺激的巨噬细胞中，PKM2与低氧诱导因子1α（HIF1α）在白细胞介素-1β（IL-1β）基因启动子处形成复合物。使用TEPP-46激活PKM2可减弱脂多糖刺激的巨噬细胞中Sirt5缺陷介导的IL-1β上调。最后，我们发现Sirt5缺陷小鼠更容易患葡聚糖硫酸钠（DSS）诱导的结肠炎，这与Sirt5缺陷促使PKM2高琥珀酰化并促进IL-1β产生有关。总之，我们的研究结果揭示了一种机制，即SIRT5至少部分通过调节PKM2的琥珀酰化、活性和功能来抑制巨噬细胞中的促炎反应。
