Circadian Mechanisms of Diabetes Prevention in Aged mice

老年小鼠糖尿病预防的昼夜节律机制

• 批准号: 10183131
• 负责人: Rajat Singh
• 金额: $ 41.75万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10183131
• 关键词: Acute; Age; Aging; Alzheimer' s Disease; Antidiabetic Drugs; Autophagocytosis; Autophagosome; Binding; Biochemical; Blood; Blood Glucose; Caloric Restriction; Calories; Cardiovascular system; Cerebrovascular system; Clock protein; Cognition; Consumption; Coupled; Data; Diabetes Mellitus; Diabetes prevention; Dietary Intervention; Drug Design; Drug Screening; Event; Exhibits; Fatty acid glycerol esters; Food; Gene Expression; Gluconeogenesis; Gluconeogenesis Inhibition; Glucose; Glucose Intolerance; Health; Hour; Hyperglycemia; Individual; Intervention; Life; Liver; Masks; Mediating; Metabolic syndrome; Modification; Mus; Neurodegenerative Disorders; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Obesity; Pathway interactions; Pattern; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phosphorylation; Physical activity; Prevention; Property; Proteins; Proteomics; Publishing; Quality Control; Residual state; Stress; Structure; Time; United States; Vision; Work; age related; aged; circadian; cryptochrome 1; design; dietary; dietary approach; feeding; genetic approach; glucose production; healthspan; improved; inhibitor/antagonist; novel; prevent; small molecule; small molecule inhibitor

Abstract Caloric restriction (CR) extends life/healthspan in multiple species, although one drawback of CR is poor compliance. This has led to alternative dietary approaches aimed at healthspan extension. We have established an isocaloric twice-a-day (ITAD) feeding intervention wherein food is partitioned into two feeding intervals each day, without CR. ITAD mice are fed at two 2-hour intervals each day such that total calories consumed are similar to those eaten by ad-libitum (Ad-lib) controls in 24 hours. Despite absence of CR, ITAD-fed mice are protected against diabetes and metabolic syndrome of aging. The mechanisms by which ITAD feeding mediates these benefits remain unknown. Circadian-wide analyses revealed that ITAD feeding causes marked temporal shifts in patterns of the quality control pathway autophagy. Surprisingly, ITAD mice show stimulation of autophagy flux immediately after the 1st feeding window at 11am and marked suppression at 7pm. While autophagy activation at 11am increases fat utilization, suppression of autophagy at 7pm associates with inhibition of gluconeogenic gene expression and glucose production in aging mice. The mechanism by which ITAD feeding suppresses glucose production is not known. Our recently published work has shown that core clock proteins are targets for lysosomal degradation, and that autophagy specifically degrades CRY1. We have found that autophagy is stimulated from 3pm to 7pm in livers from young Ad-lib-fed mice, leading to the timed- degradation of CRY1¾a robust inhibitor of gluconeogenesis. CRY1 binds to the autophagosome marker LC3 through its LC3-Interacting Region (LIR) motifs. Acute autophagy blockage or inactivation of its LIR motifs promotes CRY1 accumulation. Since CRY1 suppresses gluconeogenesis, its accumulation blocks gluconeogenesis and lowers blood glucose. Interestingly, our preliminary data reveal that aged and obese mice each display accelerated degradation of CRY1 by autophagy, leading to sustained gluconeogenesis and hyperglycemia. Although autophagy flux typically decreases with age, we propose that age-related hyperphosphorylation of CRY1, a modification shown to trigger its degradation, favors its sequestration and rapid degradation by residual autophagy. From an interventional stand-point, our preliminary studies indicate that ITAD feeding prevents the loss of CRY1 levels at 7pm by suppressing autophagy at this time-frame. We propose that approaches preventing the age-related decline in CRY1 protein will normalize blood glucose levels and prevent diabetes. On this premise, we hypothesize that age-related hyperphosphorylation of the core circadian repressor CRY1 accelerates its autophagic degradation leading to hyperglycemia and type 2 diabetes. We propose the use of two interventions to maintain CRY1 levels in aged mice, i.e., ITAD feeding, and small molecules designed to mask LIR motifs of CRY1 and block its degradation that, in turn, will suppress gluconeogenesis and prevent age-related diabetes. In this proposal, we will: (1) Determine the age and dietary- stress-related changes in protein levels and lysosomal degradation rates of CRY1 and additional core circadian proteins in liver; (2) Determine how age-related modifications to CRY1 accelerates its degradation and alters gluconeogenesis; (3) Determine whether ITAD feeding reverses age-associated diabetes by increasing CRY1 levels, and (4) Identify small molecule inhibitors to block CRY1-LC3 interaction with potency, selectivity and favorable drug-like properties and prevent hyperglycemia is aged mice. Significance: Age-related metabolic syndrome/type 2 diabetes is a significant health problem in the United States that increases sharply to ~44% in individuals older than 50 years. Type 2 diabetes impacts healthspan through effects on cardiovascular and cerebrovascular systems, physical activity, vision, and cognition. Type 2 diabetes is thought to predispose to neurodegenerative disease, including Alzheimer’s dementia. 1

抽象的 热量限制（CR）扩展了多种物种的寿命/健康状态，尽管CR的一个缺点很差 遵守。这导致了针对HealthSpan扩展的替代饮食方法。我们已经建立了 每天两次（ITAD）喂养干预措施，将食物分为两个喂食间隔 一天，没有CR。 ITAD小鼠每天以两个2小时的间隔喂食，以使总消耗的卡路里为 类似于Ad-Libitum（AD-LIB）在24小时内用Ad-Libitum（AD-LIB）对其进行食用的类似。尽管没有CR，但ITAD喂养的小鼠是 防止糖尿病和衰老的代谢综合征。 ITAD喂养培养基的机制 这些好处仍然未知。循环范围内的分析表明，ITAD喂养导致标记为暂时的 质量控制途径自噬的模式的变化。令人惊讶的是，ITAD小鼠显示 上午11点在第一个进料窗口后立即自噬通量，并在晚上7点标记抑制。尽管 上午11点的自噬激活增加了脂肪的利用率，在晚上7点对自噬的抑制 抑制老化小鼠糖原性基因表达和葡萄糖的产生。该机制 ITAD喂养抑制葡萄糖的产生尚不清楚。我们最近发表的工作表明核心 时钟蛋白是溶酶体降解的靶标，并且自噬特异性降解CRY1。我们有 发现从年轻的Ad-Lib喂养小鼠的肝脏中，从下午3点至晚上7点刺激自噬，导致定时 - cry1¾a强大的糖异生抑制剂的降解。 CRY1与自噬体标记LC3结合 通过其LC3相互作用区域（LIR）基序。其LIR图案的急性自噬阻塞或失活 促进Cry1积累。由于Cry1抑制了糖异生，因此其积累块 糖异生并降低血糖。有趣的是，我们的初步数据表明，老化和肥胖的小鼠 每个显示器通过自噬加速CRY1的降解，导致持续的糖异生和 高血糖。尽管自噬通量通常会随着年龄的增长而下降，但我们提出了与年龄有关的 CRY1的高磷酸化，这是一种触发其降解的修饰，有利于其固存和快速 残留自噬通过降解。从介入的立场开始，我们的初步研究表明 ITAD喂养可以通过抑制此时间框架来防止晚上7点的CRY1水平损失。我们建议 这种方法可以防止CRY1蛋白与年龄相关的年龄下降，将使血糖水平正常化，并且 预防糖尿病。在这个前提下，我们假设核心昼夜节律与年龄相关的高磷酸化 阻遏物CRY1加速其自噬降解，导致高血糖和2型糖尿病。我们 建议使用两种干预措施来维持老年小鼠的CRY1水平，即ITAD喂养和小 旨在掩盖CRY1的LIR图案并阻止其降解的分子，而其降解将又会抑制 糖异生并预防与年龄相关的糖尿病。在此提案中，我们将：（1）确定年龄和饮食 CRY1的蛋白质水平和溶酶体降解率和其他核心昼夜节律的蛋白质水平的变化 肝脏中的蛋白质； （2）确定与年龄相关的CRY1的修改如何加速其降解并改变 糖异生； （3）确定ITAD喂养是否通过增加CRY1来逆转与年龄相关的糖尿病 水平和（4）识别小分子抑制剂，以阻止CRY1-LC3与效力，选择性和 有利的药物样特性和预防高血糖是老化的小鼠。 意义：与年龄相关的代谢综合征/2型糖尿病是曼联的重大健康问题 在50岁以上的个体中，急剧增加到约44％。 2型糖尿病会影响HealthSpan 通过对心血管和脑血管系统的影响，体育活动，视力和认知。类型2 糖尿病被认为易感神经退行性疾病，包括阿尔茨海默氏症的痴呆症。 1