SIRT1 and muscle insulin sensitivity

SIRT1 和肌肉胰岛素敏感性

• 批准号: 8706753
• 负责人: Simon Schenk
• 金额: $ 30.77万
• 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/8706753
• 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，是2型糖尿病（T2 D）病因学的主要缺陷。然而，肌肉中将年龄与胰岛素抵抗联系起来的信号机制尚不清楚。考虑到2010年，美国65岁及以上人群中约有27%患有T2 D，并且在未来20年内，65岁及以上人群预计将翻一番，达到约7000万，因此必须解决这一根本性的知识差距。因此，本研究的长期目标是确定衰老过程中肌肉胰岛素抵抗的机制。热量限制（CR;定义为60%的随意[AL]食物摄入量）有力地逆转了肌肉胰岛素抵抗，并延迟了其在衰老过程中的发作。NAD+依赖性蛋白脱乙酰酶，sirtuin 1（SIRT 1）被CR激活，被认为是连接年龄和CR与肌肉胰岛素作用的假定信号节点。然而，令人惊讶的是，关于SIRT 1对肌肉胰岛素作用的调节作用，特别是在体内，是非常有限的。我们的中心假设是SIRT 1是一种关键的信号分子，它将衰老和CR与肌肉胰岛素作用联系起来，主要通过调节主要信号节点的乙酰化，如信号转导和转录激活因子3（STAT 3），然后影响许多信号通路，包括胰岛素信号通路。为了解决这一假设，我们的方法将是使用新型小鼠模型研究肌肉胰岛素信号传导和敏感性对年龄和CR的反应，其中我们专门在肌肉中操纵SIRT 1活性。我们的模型预测，SIRT 1活性在衰老过程中的变化，以及对CR的反应，导致SIRT 1靶蛋白乙酰化状态和随后活性的变化，直接或间接调节肌肉胰岛素信号传导和敏感性。具体地，目标#1将阐明SIRT 1和STAT 3对衰老小鼠中肌肉胰岛素抵抗的发病机理的贡献，而目标#2将确定SIRT 1-STAT 3信号传导轴是否是CR增强小鼠中肌肉胰岛素敏感性的能力的基础。对于这些研究，我们将测量肌肉胰岛素信号和胰岛素敏感性，在体内，使用高胰岛素-正葡萄糖钳夹，和离体，使用2-脱氧葡萄糖摄取测定，在年轻的（4个月），中年在一些实施方案中，对喂食AL饮食的小鼠（12个月）和老年（20个月）进行测量，并将它们与喂食短期（30天）或长期（9或17个月）CR饮食的小鼠中的测量进行比较。将在4只不同的转基因小鼠中进行研究，这些小鼠具有SIRT 1活性的肌肉特异性增加、SIRT 1脱乙酰酶活性的敲除（KO）、STAT 3的KO或SIRT 1和STAT 3的KO。在目标#3中，我们将使用质谱技术和基于腺病毒的肌肉细胞研究来鉴定SIRT 1的新靶点及其乙酰化对胰岛素作用的功能影响。总之，这些研究将拓宽我们对SIRT 1在肌肉生物学中作用的理解，并可能对治疗肌肉胰岛素抵抗以及骨骼肌中其他衰老疾病的疗法的发展产生广泛影响。