Elucidating the pathophysiology and molecular mechanisms of renal insulin resistance

阐明肾胰岛素抵抗的病理生理学和分子机制

• 批准号: 10590598
• 负责人: Brandon Hubbard
• 金额: $ 3.26万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-16 至 2026-03-15
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10590598
• 关键词: Alanine; American; Analytical Chemistry; Cell membrane; Cellular biology; Chronic Disease; Closure by clamp; Complex; Crystallization; Data; Defect; Development; Diabetes Mellitus; Diet; Diglycerides; Fatty acid glycerol esters; Functional disorder; Gluconeogenesis; Glucose; Glutamine; Goals; Hepatic; High Fat Diet; Homeostasis; Impairment; Insulin; Insulin Receptor; Insulin Resistance; Isotopes; Kidney; Knock-in Mouse; Learning; Lipids; Liver; Measures; Mediating; Medical; Metabolic; Methodology; Methods; Molecular; Mus; Mutate; Non-Insulin-Dependent Diabetes Mellitus; Organ; Pathogenesis; Phosphorylation; Phosphorylation Site; Physiology; Play; Protein Kinase; Proto-Oncogene Proteins c-akt; Public Health; Pyruvate; Role; Seminal; Signal Transduction; Techniques; Testing; Tracer; United States; blood glucose regulation; cell type; clinically relevant; experience; feeding; glucose production; insight; insulin signaling; interest; kidney cortex; metabolic phenotype; mouse model; novel; novel therapeutics; oxidation; protein activation; transcriptomics

Project Summary Type 2 diabetes (T2D) is one of the defining medical challenges of the 21st century, with one in three Americans born in 2000 estimated to develop diabetes in their lifetime. T2D is characterized by multi-organ insulin resistance and perturbed whole-body glucose homeostasis. Over the past three decades, there have been hints that the kidney plays a central pathophysiologic role in dysregulated whole-body glucose homeostasis in diabetes, with a seminal study suggesting renal glucose production to be increased 300%, climbing to 85% that of the liver. Notwithstanding, insulin resistance in the kidney has remained controversial and any potential mechanisms are unknown. It would be of great public health interest to crystallize the mechanisms and precise pathophysiology of insulin resistance in the kidney, as this may have myriad translational implications. In this proposal, we will build upon our strong preliminary evidence that the renal cortex does, indeed, become insulin resistant with high fat diet (HFD) feeding. In further preliminary data, we have observed both diacylglycerol (DAG) accumulation and Protein Kinase Cε (PKCε) translocation in the mouse renal cortex, raising the possibility that diet-induced renal insulin resistance may be mediated by a similar mechanism as in the liver, where high fat feeding leads to DAG accumulation, which activates PKCε. PKCε subsequently phosphorylates insulin receptor (IR) at Thr1160, causing abrogated insulin signaling. In this proposal, we will carefully assess the insulin signaling defects associated with renal insulin resistance and also further characterize if there is aberrant DAG-PKCe-IR axis activation. We will also use two novel 13C isotopic tracer strategies to understanding oxidative and gluconeogenic defects in the insulin resistant renal cortex. Further, we will directly test the hypothesis that the DAG-PKCe-IR axis causes renal insulin resistance by utilizing an already-generated mouse model where the critical Thr1160 residue of IR is mutated to an alanine, which cannot be phosphorylated by PKCε. We predict these mice will be protected from signaling and metabolic flux manifestations of renal insulin resistance when fed a HFD. This proposal represents an integrated scientific approach and new learning experiences that harness techniques of physiology, cell biology, and analytical chemistry to yield novel insights into the mechanisms and pathophysiology or renal insulin resistance.

项目摘要 2型糖尿病（T2 D）是21世纪世纪的重大医学挑战之一，每三个美国人中就有一个患有这种疾病 2000年出生的人估计一生中会患上糖尿病。2型糖尿病的特点是多器官胰岛素抵抗 并扰乱了全身葡萄糖平衡。在过去的三十年里，有迹象表明， 肾脏在糖尿病全身葡萄糖稳态失调中起着重要的病理生理作用， 一项开创性的研究表明，肾脏的葡萄糖产量增加了300%，攀升至肝脏的85%。 尽管如此，肾脏中的胰岛素抵抗仍然存在争议，任何潜在的机制都是不确定的。 未知这将是巨大的公共卫生利益，明确的机制和精确的病理生理学 胰岛素抵抗在肾脏，因为这可能有无数的翻译影响。在本提案中，我们将 基于我们强有力的初步证据，即肾皮质确实会在高血糖时产生胰岛素抵抗， 脂肪饮食（HFD）喂养。在进一步的初步数据中，我们观察到二酰基甘油（DAG）的积累 和蛋白激酶Cε（PKCε）易位，提高了饮食诱导的可能性。 肾脏胰岛素抵抗可能是由与肝脏相似的机制介导的，在肝脏中高脂肪喂养导致 DAG积聚，激活PKCε。PKCε随后在Thr 1160磷酸化胰岛素受体（IR）， 导致胰岛素信号传导消失。在本提案中，我们将仔细评估胰岛素信号传导缺陷 与肾胰岛素抵抗相关，并且还进一步表征是否存在异常DAG-PKCe-IR轴 activation.我们还将使用两种新的13 C同位素示踪剂策略来了解氧化和生烃 胰岛素抵抗肾皮质的缺陷。此外，我们将直接检验DAG-PKCe-IR 轴引起肾胰岛素抵抗，通过利用已经产生的小鼠模型，其中关键Thr 1160 IR的残基突变为丙氨酸，其不能被PKCε磷酸化。我们预测这些老鼠 当喂食HFD时，保护免受肾胰岛素抵抗的信号传导和代谢通量表现。这 建议代表了一种综合的科学方法和新的学习经验， 生理学，细胞生物学和分析化学，以产生新的见解的机制， 病理生理学或肾胰岛素抵抗。