SIRT1 and muscle insulin sensitivity

SIRT1 和肌肉胰岛素敏感性

基本信息

批准号：
8918077
负责人：
Simon Schenk
金额：
$ 15.5万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8918077
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

项目摘要

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）：胰岛素抵抗是衰老肌肉中常见的代谢并发症，也是 2 型糖尿病 (T2D) 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传导机制尚不清楚。考虑到 2010 年，美国 65 岁及以上人群中约有 27% 患有 T2D，并且在未来 20 年中，65 岁及以上人口预计将翻一番，达到约 7000 万，因此必须缩小这一根本差距在知识上得到解决。因此，这项研究的长期目标是确定衰老过程中肌肉胰岛素抵抗的潜在机制。热量限制（CR；定义为随意摄入 [AL] 食物摄入量的 60%）可有效逆转肌肉胰岛素抵抗，并延缓其在衰老过程中的发生。 NAD+ 依赖性蛋白脱乙酰酶 Sirtuin 1 (SIRT1) 被 CR 激活，并且被认为是将年龄和 CR 与肌肉胰岛素作用联系起来的推定信号节点。然而，令人惊讶的是，关于 SIRT1 对肌肉胰岛素作用的调节作用（特别是在体内）的知识非常有限。我们的中心假设是 SIRT1 是一种关键信号分子，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转导节点的乙酰化，例如信号转导子和转录激活子 3 (STAT3)，然后影响许多信号转导通路，包括胰岛素信号通路。为了解决这一假设，我们的方法是使用新型小鼠模型来研究肌肉胰岛素信号传导和对年龄和 CR 的敏感性，在该模型中，我们专门操纵了肌肉中的 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 的反应，会导致 SIRT1 靶蛋白的乙酰化状态和随后的活性发生变化，从而直接或间接调节肌肉胰岛素信号传导和敏感性。具体来说，目标#1将阐明SIRT1和STAT3对衰老小鼠肌肉胰岛素抵抗发病机制的贡献，而目标#2将确定SIRT1-STAT3信号轴是否是CR增强小鼠肌肉胰岛素敏感性能力的基础。对于这些研究，我们将使用高胰岛素正常血糖钳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-脱氧葡萄糖摄取测定在体外测量年轻（4 个月）、中年（12 个月）和老年人的肌肉胰岛素信号传导和胰岛素敏感性。（20 个月）喂食 AL 饮食的小鼠，并将其与喂食短期（30 天）或长期（9 或 17 个月）CR 饮食的小鼠的测量结果进行比较。研究将在 4 只不同的转基因小鼠中进行，这些小鼠要么肌肉特异性增加 SIRT1 活性，要么敲除 SIRT1 脱乙酰酶活性，要么敲除 STAT3，要么敲除 SIRT1 和 STAT3。在目标 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识别 SIRT1 的新靶点及其乙酰化对胰岛素作用的功能影响。总而言之，这些研究将拓宽我们对 SIRT1 在肌肉生物学中的作用的理解，并且可能对治疗肌肉胰岛素抵抗以及其他骨骼肌衰老疾病的疗法的开发产生广泛影响。