Sir2 regulation and chemical modulation

描述（由申请人提供）：拟议研究的目的是推断控制酵母和人类细胞中sirtuin酶活性的机制和调节原理。这些原理将用于设计可以激活细胞内sirtuins的小分子。Sirtuins调节一系列重要的生物活动，包括抗逆性、基因沉默和长寿。Sirtuins与调节与卡路里限制相关的生物效应有关。限制卡路里已被证明对哺乳动物有许多积极的健康益处，包括减少脂肪生成、胰岛素敏感性和延长寿命。这些生物效应引起了人们对sirtuins的酶促机制、它们在细胞中被调节的方式以及它们可能被药理学调节以改善人类健康的方式的兴趣。Sirtuins是NAD依赖的去乙酰化酶，它去除乙酰赖氨酸修饰的组蛋白和转录因子的乙酰基，从而调节染色质和基因表达。我们和其他人已经证明，这些活动受到细胞内NAD和烟酰胺水平的调节，并且sirtuins能够整合来自能量和代谢状态的信息来控制遗传事件。为了更好地了解这些酶的功能以及它们如何在细胞中被调节，我们建议研究以下具体目标：在Aim1中，我们建议表征这类独特酶的生化功能，强调它们的化学新颖性和NAD在去乙酰化反应中的结合。在目的2中，我们建议展示酶活性如何为烟酰胺调节sirtuin活性提供机制。此外，通过最近开发的质谱分析方法，我们希望对烟酰胺如何调节细胞中的sirtuins获得新的见解。在Aim 3中，我们从sirtuin反应机制和烟酰胺调节机制的知识出发，探索sirtuin小分子激活剂的开发。这些激活剂体现了一种上调细胞中sirtuin作用的新方法，并为药物干预提供了一个潜在的切入点，以增加细胞抗逆性和细胞存活率。这些目标的实现有望为这些酶的生物化学和调控提供新的见解，并为激活sirtuins治疗糖尿病和退行性疾病的新疗法提供概念证明。

DESCRIPTION (provided by applicant): The objective of the proposed research is to deduce mechanistic and regulatory principles that control the activities of sirtuin enzymes in yeast and human cells. These principles will be used to design small molecules that can activate sirtuins in cells. Sirtuins regulate a host of biologically significant activities including stress resistance, gene silencing and longevity. Sirtuins are implicated in mediating biological effects associated with calorie restriction. Calorie restriction has been shown to have numerous positive health benefits in mammals including reduced adipogenesis, insulin sensitivity and increased lifespan. These biological effects have raised interest in the enzymatic mechanisms of sirtuins, the means by which they are regulated in cells and the ways in which they might be modulated pharmacologically for improved human health. Sirtuins are NAD dependent deacetylases that remove acetyl-groups of acetyllysine modified histones and transcription factors thereby regulating chromatin and gene expression. We and others have demonstrated that these activities are regulated by NAD and nicotinamide levels in cells, and that the sirtuins are able to integrate information from energy and metabolic states to control genetic events. As part of our goal to better understand the functions of these enzymes and how they can be modulated in cells we propose to investigate the following specific aims: In Aim1 we propose to characterize the biochemical functions of this unique class of enzymes, emphasizing their chemical novelty and the incorporation of NAD in deacetylation reactions. In Aim2 we propose to show how enzymatic activity provides a mechanism for nicotinamide regulation of sirtuin activity. In addition with a recently developed mass spectrometry method we hope to gain new insights into how nicotinamide regulates sirtuins in cells. In Aim 3 we explore the development of small molecule activators of sirtuins designed from knowledge of the sirtuin reaction mechanism and the mechanism of nicotinamide regulation. These activators embody a novel approach to upregulate sirtuin action in cells and provide a potential entrypoint for pharmacological intervention to increase cell stress resistance and cell survival. Achievement of these aims is expected to provide new insights into the biochemistry and regulation of these enzymes, and provide proof of concept for new therapeutics that can activate sirtuins to treat diabetes and degenerative disorders.