Receptor-mediated glucose sensing and skeletal muscle function

受体介导的葡萄糖传感和骨骼肌功能

基本信息

批准号：
10540309
负责人：
George Kyriazis
金额：
$ 39万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-01 至 2025-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10540309
关键词：
Ablation Acceleration Actins Address Adult Attenuated Bioenergetics Biological Availability Cell Lineage Cells Cellular Metabolic Process Data Deacetylase Development Diabetes Mellitus Endocrine Energy Metabolism Equilibrium Etiology Exercise Tolerance FRAP1 gene Fasting Fructose Functional disorder G-Protein-Coupled Receptors Genes Genetic Glucose Growth Growth and Development function Heterodimerization Hormonal Human Hypertrophy Immobilization Ingestion Innovative Therapy Insulin Insulin Resistance Intramuscular Isotope Labeling Knockout Mice Limb structure Link MAPK1 gene Maintenance Measures Mechanics Mediating Metabolic Metabolic Control Metabolic Pathway Metabolic dysfunction Metabolism Mitochondria Molecular Molecular Target Morphology Mus Muscle Muscle Development Muscle function Muscular Atrophy Myogenin Neurons Nicotinamide adenine dinucleotide Non-Insulin-Dependent Diabetes Mellitus Nucleotide Biosynthesis Nutrient Obese Mice Obesity Outcome Oxidation-Reduction Pathogenesis Pathway interactions Pharmacological Treatment Phenotype Physiological Poly(ADP-ribose) Polymerases Polymerase Prevention therapy Process Protein Biosynthesis Proteins Protocols documentation Reaction Receptor Signaling Regulation Reporter Reporting Role SIRT1 gene Signal Pathway Signal Transduction Sirtuins Skeletal Muscle Stimulus Taste Buds Testing Thinness Tongue blood glucose regulation defined contribution detection of nutrient diet-induced obesity fitness functional adaptation glucose sensor glucose tolerance improved in vivo inhibitor knock-down muscle degeneration muscle form muscle hypertrophy novel nucleic acid biosynthesis obesity genetics oxidation pharmacologic pleiotropism postnatal preservation prevent receptor response sensor skeletal skeletal muscle plasticity skeletal muscle wasting spatiotemporal sweet taste perception treatment response uptake

项目摘要

PROJECT SUMMARY Skeletal muscle is central to the development of metabolic dysfunction during type 2 diabetes (T2D) and obesity. In addition, these conditions are often accompanied by accelerated muscle loss despite the presence of nutrient excess. This suggests uncoupling of nutrient sensing mechanisms with the molecular pathways that control muscle plasticity. For instance, depletion of intramuscular nicotinamide adenine dinucleotide (NAD) is linked to skeletal muscle loss and dysfunction, while strategies that restore or increase its levels can reverse this pathogenesis. Particularly, genetic or pharmacological inhibition of poly(ADP-ribose) polymerases 1 (PARP1), a major NAD consumer, improves muscle fitness through increases in NAD availability and the activation of NAD-dependent deacetylase sirtuin-1 (SIRT1). Thus, identifying physiological pathways that link energy metabolism to the regulation of PARP1 activity can lead to the development of innovative therapies for the prevention or treatment of muscle degeneration and metabolic dysfunction. Preliminary data suggest that direct sensing of circulating glucose by sweet taste receptors (STRs) regulates PARP1 activity to control the adaptive potential of skeletal muscle. Specifically, whole body or skeletal muscle-specific deletion of T1r2 gene of STRs (T1R2-KO) enhances mitochondrial function, oxidative capacity, exercise tolerance, and induces mild increases in myofiber size. These improvements are linked to attenuated PARP1 activity, increased NAD pool, and enhanced glucose utilization towards nucleotide biosynthesis. Consequently, T1R2-KO mice are protected from metabolic derangements associated with diet-induced obesity, including muscle mass loss. Thus, it was hypothesized that the T1R2 receptor is a constitutive sensor of glucose availability to adjust intracellular pathways that control the metabolic basis of skeletal muscle plasticity. This hypothesis is tested through comprehensive studies using mice with constitutive or inducible muscle-specific deletion of the T1r2 gene to: 1) Elucidate the role of T1R2 signaling network in the regulation of muscle bioenergetics and function. Specifically, a) probe signaling pathway leading to PARP1 regulation and NAD bioavailability, b) identify downstream effectors of NAD-dependent activation of SIRT1 and 2, c) assess contributions of STRs in the regulation of substrate utilization, and d) determine interactions between STR signaling and established intracellular energy sensors (i.e. AMPK, mTORC1, Akt). 2) Investigate contributions of T1R2-mediated glucose sensing in the regulation of muscle mass. Specifically, a) assess physiological effects of inducible deletion of STR signaling in adult skeletal muscle to mimic longitudinal effects of pharmacological treatments targeting STRs, b) define contributions of STR signaling to muscle mass adaptations in response to treatments that induce muscle hypertrophy or atrophy, c) spatiotemporal expression of T1r2 gene during muscle development and growth using muscle-specific reporter mice, and d) contributions of STR signaling during postnatal muscle growth through the assessment of morphological, signaling and functional muscle adaptations. .

项目概要骨骼肌对于 2 型糖尿病 (T2D) 和代谢功能障碍的发展至关重要肥胖。此外，尽管存在这些情况，但通常会伴随着加速的肌肉损失。的营养过剩。这表明营养传感机制与分子途径脱钩控制肌肉的可塑性。例如，肌内烟酰胺腺嘌呤二核苷酸（NAD）的消耗是与骨骼肌损失和功能障碍有关，而恢复或增加其水平的策略可以逆转此病机。特别是，聚（ADP-核糖）聚合酶的遗传或药理学抑制1 (PARP1) 是 NAD 的主要消费者，通过增加 NAD 的可用性和 NAD 依赖性脱乙酰酶 Sirtuin-1 (SIRT1) 的激活。因此，确定连接的生理途径能量代谢对 PARP1 活性的调节可以导致创新疗法的开发预防或治疗肌肉退化和代谢功能障碍。初步数据表明通过甜味受体（STR）直接感应循环葡萄糖调节 PARP1 活性以控制骨骼肌的适应潜力。具体来说，T1r2 基因的全身或骨骼肌特异性缺失 STR (T1R2-KO) 增强线粒体功能、氧化能力、运动耐量，并诱导轻度肌纤维尺寸增加。这些改进与 PARP1 活性减弱、NAD 池增加、并增强葡萄糖对核苷酸生物合成的利用。因此，T1R2-KO 小鼠受到保护与饮食引起的肥胖相关的代谢紊乱，包括肌肉质量损失。因此，这是假设 T1R2 受体是葡萄糖可用性的组成型传感器，可调节细胞内控制骨骼肌可塑性代谢基础的途径。该假设通过检验使用具有 T1r2 基因组成型或诱导型肌肉特异性缺失的小鼠进行综合研究：1) 阐明 T1R2 信号网络在肌肉生物能量和功能调节中的作用。具体来说，a) 探测导致 PARP1 调节和 NAD 生物利用度的信号通路，b) 识别 SIRT1 和 2 的 NAD 依赖性激活的下游效应器，c) 评估 STR 在底物利用的调节，d) 确定 STR 信号传导与已建立的细胞内能量传感器（即 AMPK、mTORC1、Akt）。 2) 研究T1R2介导的葡萄糖的贡献肌肉质量调节中的传感。具体来说，a) 评估诱导性缺失的生理效应成人骨骼肌中的 STR 信号传导可模拟靶向药物治疗的纵向效应 STR，b) 定义了 STR 信号传导对响应治疗的肌肉质量适应的贡献诱导肌肉肥大或萎缩，c) 肌肉发育过程中 T1r2 基因的时空表达使用肌肉特异性报告小鼠进行生长和生长，以及 d) STR 信号传导在产后肌肉过程中的贡献通过评估形态、信号传导和功能性肌肉适应来评估生长。。