SIRT1 and muscle insulin sensitivity

SIRT1 和肌肉胰岛素敏感性

• 批准号: 8516958
• 负责人: Simon Schenk
• 金额: $ 28.54万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8516958
• 关键词: Acetylation; Address; Adverse effects; Advocate; Age; Aging; Attenuated; Bioinformatics; Biological Assay; Biology; Caloric Restriction; Complication; Data; Deacetylase; Deacetylation; Defect; Deoxyglucose; Diet; Disease; Eating; Etiology; Euglycemic Clamping; Fostering; Genetic Transcription; Glucose Clamp; Health; Human; Individual; Insulin; Insulin Resistance; Insulin Signaling Pathway; Intake; Knock-out; Knowledge; Link; Lysine; Mass Spectrum Analysis; Measurement; Measures; Mediating; Metabolic; Modeling; Mus; Muscle; Muscle Cells; Non-Insulin-Dependent Diabetes Mellitus; Older Population; Pathogenesis; Pathway interactions; Phosphatidylinositols; Phosphotransferases; Proteins; Quality of life; Regulation; Research; Risk; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Site-Directed Mutagenesis; Skeletal Muscle; Stat3 protein; Systems Biology; TNFRSF5 gene; Techniques; Therapeutic; Transgenic Mice; United States; age effect; aged; anti aging; base; defined contribution; design; feeding; glucose transport; human MPP1 protein; improved; in vivo; insulin sensitivity; insulin signaling; mouse model; muscle aging; novel; overexpression; prevent; research study; response; therapy development; uptake

DESCRIPTION (provided by applicant): Insulin resistance is a common metabolic complication in aged muscle, and is a primary defect underlying the etiology of type 2 diabetes (T2D). However, the signaling mechanisms in muscle linking age to insulin resistance are unknown. Considering that in 2010, ~27% of individuals 65 yrs and older in the United States were afflicted with T2D, and in the next 20 years the 65 and older population is anticipated to double to ~70 million, it is imperative that this fundamental gap in knowledge be resolved. Thus, the long-term objective of this research is to define the mechanisms underlying muscle insulin resistance in aging. Caloric restriction (CR; defined as 60% of ad libitum [AL] food intake) robustly reverses muscle insulin resistance, and delays its onset during aging. The NAD+-dependent protein deacetylase, sirtuin 1 (SIRT1) is activated by CR, and is thought to be the putative signaling node linking age and CR to muscle insulin action. Surprisingly, however, knowledge regarding the regulatory role of SIRT1 on muscle insulin action, particularly, in vivo, is remarkably limited. Our central hypothesis is that SIRT1 is a key signaling molecule that links aging and CR to muscle insulin action, primarily by modulating the acetylation of major signaling nodes, such as signal transducer and activator of transcription 3 (STAT3), that then influence many signaling pathways, including the insulin signaling pathway. To address this hypothesis, our approach will be to study muscle insulin signaling and sensitivity in response to age and CR using novel mouse models, in which we have manipulated SIRT1 activity specifically in muscle. Our model predicts that changes in SIRT1 activity during aging, and in response to CR, leads to changes in the acetylation status and subsequent activity of SIRT1 target proteins, which directly or indirectly regulates muscle insulin signaling and sensitivity. Specifically, Aim #1 wil elucidate the contribution of SIRT1 and STAT3 to the pathogenesis of muscle insulin resistance in aging mice, whilst Aim #2 will determine whether a SIRT1- STAT3 signaling axis underlies the ability of CR to enhance muscle insulin sensitivity in mice. For these studies, we will measure muscle insulin signaling and insulin sensitivity, in vivo, using hyperinsulinemic- euglycemic clamps, and ex vivo, using 2-deoxyglucose uptake assays, in young (4 months), mid-aged (12 months) and old (20 months) mice fed an AL diet, and compare them to measurements in mice fed a short- term (30 d) or long-term (9 or 17 months) CR diet. Studies will be conducted in 4 different transgenic mice with either a muscle-specific increase of SIRT1 activity, knockout (KO) of SIRT1 deacetylase activity, KO of STAT3 or KO of SIRT1 and STAT3. In Aim #3, we will use mass spectrometry techniques and adenoviral-based studies in muscle cells to identify novel targets of SIRT1 and the functional effects of their acetylation on insulin action. Altogether, these studies will broaden our understanding of the role of SIRT1 in muscle biology, and may have wide-reaching impact on the development of therapies to treat not only muscle insulin resistance, but also other diseases of aging in skeletal muscle.!

描述（由申请人提供）：胰岛素抵抗是老年肌肉中常见的代谢并发症，并且是2型糖尿病病因（T2D）病因的主要缺陷。但是，肌肉将年龄与胰岛素抵抗联系起来的信号传导机制尚不清楚。考虑到2010年，在美国65岁及以上的个人中，约有27％遭受了T2D的困扰，在接下来的20年中，预计65岁及65岁的老年人口将翻一番，至约7000万，因此，必须解决这一知识的根本差距。因此，这项研究的长期目标是定义衰老中肌肉胰岛素抵抗的机制。热量限制（CR；定义为多余的食物摄入量的60％）可稳健地逆转肌肉胰岛素抵抗，并在衰老期间延迟其发作。 NAD+依赖性蛋白脱乙酰基酶SIRTUIN 1（SIRT1）被CR激活，被认为是推定的信号传导节点，将年龄与CR连接到肌肉胰岛素作用。但是，令人惊讶的是，有关SIRT1在肌肉胰岛素作用方面的调节作用的知识，尤其是体内的知识非常有限。我们的中心假设是SIRT1是将衰老和CR与肌肉胰岛素作用联系起来的关键信号分子，主要是通过调节主要信号节点的乙酰化（例如信号传感器和转录3（STAT3）的激活剂）的乙酰化，然后影响许多信号通路，包括胰岛素信号通路，包括许多信号通路。为了解决这一假设，我们的方法是使用新颖的小鼠模型研究肌肉胰岛素信号传导和敏感性，并使用新型小鼠模型，其中我们在肌肉中专门操纵SIRT1活性。我们的模型预测，衰老过程中SIRT1活性的变化以及对CR的响应，会导致乙酰化状态的变化以及SIRT1靶蛋白的随后活性，这些蛋白直接或间接调节肌肉胰岛素信号传导和敏感性。具体而言，AIM＃1 WIL阐明了SIRT1和STAT3对老化小鼠肌肉胰岛素抵抗的发病机理的贡献，而AIM＃2将确定SIRT1-STAT3信号轴是否是CR能够增强小鼠肌肉胰岛素敏感性的能力。对于这些研究，我们将使用高胰岛素血糖夹夹在体内测量肌肉胰岛素信号传导和胰岛素敏感性，并使用2-脱氧葡萄糖的摄取测定法，年轻（4个月），中期（12个月）和（20个月）和（20个月）的饮食和饮食（30次饮食）（30次饮食）（30个术语）（30个术语）（30次）或（分别）（30个饮食）（30个术语）（30次）或（分别）（30个饮食）（30个饮食）（30次）或衡量AL（30个）或（30个），该饮食（30个术语）（30个饮食）（30个）或（30个）或（30个）均使用过量的或（30个饮食）（30个）或（30个）或（30次）。 17个月）CR饮食。研究将在4种不同的转基因小鼠中进行，其SIRT1活性的肌肉特异性增加，SIRT1脱乙酰基酶活性的基因敲除（KO），STAT3的KO或SIRT1和STAT3的KO。在AIM＃3中，我们将在肌肉细胞中使用质谱技术和基于腺病毒的研究来鉴定SIRT1的新靶标及其乙酰化对胰岛素作用的功能效应。总的来说，这些研究将扩大我们对SIRT1在肌肉生物学中的作用的理解，并可能对不仅治疗肌肉胰岛素抵抗的疗法的发展产生广泛的影响，而且还对骨骼肌衰老的其他疾病进行治疗。