Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA.
Cell Rep. 2018 Jul 3;24(1):209-223.e6. doi: 10.1016/j.celrep.2018.05.088.
SIRT3 is a nicotinamide adenine dinucleotide (NAD)-dependent mitochondrial protein deacetylase purported to influence metabolism through post-translational modification of metabolic enzymes. Fuel-stimulated insulin secretion, which involves mitochondrial metabolism, could be susceptible to SIRT3-mediated effects. We used CRISPR/Cas9 technology to manipulate SIRT3 expression in β cells, resulting in widespread SIRT3-dependent changes in acetylation of key metabolic enzymes but no appreciable changes in glucose- or pyruvate-stimulated insulin secretion or metabolomic profile during glucose stimulation. Moreover, these broad changes in the SIRT3-targeted acetylproteome did not affect responses to nutritional or ER stress. We also studied mice with global SIRT3 knockout fed either standard chow (STD) or high-fat and high-sucrose (HFHS) diets. Only when chronically fed HFHS diet do SIRT3 KO animals exhibit a modest reduction in insulin secretion. We conclude that broad changes in mitochondrial protein acetylation in response to manipulation of SIRT3 are not sufficient to cause changes in islet function or metabolism.
SIRT3 是一种烟酰胺腺嘌呤二核苷酸（NAD）依赖性线粒体蛋白去乙酰化酶，据称通过代谢酶的翻译后修饰来影响代谢。涉及线粒体代谢的燃料刺激胰岛素分泌可能容易受到 SIRT3 介导的影响。我们使用 CRISPR/Cas9 技术在β细胞中操纵 SIRT3 的表达，导致关键代谢酶的乙酰化广泛依赖 SIRT3，但在葡萄糖刺激期间，葡萄糖或丙酮酸刺激的胰岛素分泌或代谢组学特征没有明显变化。此外，SIRT3 靶向乙酰化蛋白质组中的这些广泛变化不会影响对营养或内质网应激的反应。我们还研究了喂食标准饮食（STD）或高脂肪高蔗糖（HFHS）饮食的全身性 SIRT3 敲除小鼠。只有在慢性喂食 HFHS 饮食时，SIRT3 KO 动物才会表现出胰岛素分泌的适度减少。我们得出结论，SIRT3 操纵引起的线粒体蛋白乙酰化的广泛变化不足以导致胰岛功能或代谢的变化。
