In vivo systems to discover mechanisms regulating human islet alpha cell function

体内系统发现调节人类胰岛α细胞功能的机制

基本信息

批准号：
10228762
负责人：
Seung K Kim
金额：
$ 53.9万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-04 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10228762
关键词：
Address Affect Alpha Cell Architecture B-Lymphocytes Beta Cell Biological Assay Biological Models Biology Cell physiology Cells Cellular biology Chromatin Coupled Diabetes Mellitus Disease Electrophysiology (science)Environment Exons Functional disorder Gene Expression Regulation Genes Genetic Genetic Transcription Genetic study Genomic approach Genomics Glucagon Glucose Health Hormonal Hormones Human Hyperglycemia Impairment In Vitro Insulin Insulin Resistance Insulin-Dependent Diabetes Mellitus Investigation Islet Cell Islets of Langerhans Lead Lipids Measurement Measures Medical Metabolic Methods Modernization Molecular Mus Non-Insulin-Dependent Diabetes Mellitus Organ Organelles Output Pancreatic Diseases Pathologic Pathology Phenotype Physiological Physiology Population Production Property Regulation Research Research Personnel Resolution Risk Rodent Role Signal Transduction Structural Protein System Testing Time Toxic effect Transplantation Visual Work base diabetes pathogenesis diabetes risk diabetic diet-induced obesity disease phenotype flexibility gene function genetic approach in vitro Assay in vivo islet novel preproglucagons reconstitution response tool transcription factor transcriptome

项目摘要

Type 1 and Type 2 diabetes mellitus are recognized as bi-hormonal diseases reflecting pathology in both insulin-producing islet b-cells and glucagon-producing islet a-cells. While intensive global efforts have focused on b-cell biology and replacement, little is known about the genetic or molecular effectors of a-cell activity in health or in diabetes, especially in human islets. Discovery of molecular mechanisms that govern human a-cell gene regulation and physiological functions like glucagon output are urgently needed. We have generated new tools to measure human a-cell function and regulation in vivo, and at single-cell resolution. We propose the following scientifically-timely and medically-relevant Aims that will define regulators of human a-cells: 1. Identify mechanisms regulating human a-cell function. To enable unprecedented studies of human glucagon secretion and regulation, we generated NOD.Cg-Prkdc scidIl2rgtm1WjlSz mice (NSG) with an in-frame deletion of preproglucagon exon 3 that encodes Glucagon 1-29; termed GKO-NSG. These mice permit quantification of regulated glucagon secretion from transplanted human a-cells. Genetic, physiological, and genomic approaches in vitro and in vivo will be used to identify mechanisms governing human a-cell function. Specifically, we will analyze how a-cells are impacted by transcription factors, MAFB and RFX6, which our analysis indicates are enriched in a distinct, functionally active cell population. 2. Investigate the role of lipid droplets in human a-cell adaptive responses to lipotoxicity. Lipotoxicity and accompanying insulin resistance is an established risk for diabetes pathogenesis in humans. We will use genetic approaches and physiological assays in vitro and in vivo to identify mechanisms governing accumulation of lipid droplets (LDs), an organelle in human islets. These studies will test the hypothesis that LDs regulate function of human a-cells challenged by lipotoxicity and insulin resistance. This work allows previously unattainable investigation of physiological mechanisms governing and regulating human a-cells. A fundamental advance in diabetes and islet biology research would be the identification and characterization of factors that lead to decreased islet cell function in those with diabetes, or at risk for developing diabetes. Mechanisms governing function of human islet a-cells should be revealed by the studies proposed here. Our work should establish paradigms that connect gene transcriptional and organelle regulation to control of key a-cell physiological functions in healthy and diseased pancreatic islets. Appropriately regulated islet a-cell function is an essential feature of health, and our work will have broad impact by describing ways to ameliorate islet a-cell function, in both normal and pathological conditions.

1 型和 2 型糖尿病被认为是双激素疾病，反映了产生胰岛素的胰岛 b 细胞和产生胰高血糖素的胰岛 a 细胞的病理学。虽然全球的努力集中在 b 细胞生物学和替代上，但人们对健康或糖尿病中 a 细胞活性的遗传或分子效应知之甚少，尤其是在人类胰岛中。迫切需要发现控制人类 a 细胞基因调控和胰高血糖素输出等生理功能的分子机制。我们已经开发出新的工具来测量人类 a 细胞的功能和体内调节，并以单细胞分辨率。我们提出以下科学及时且医学相关的目标，这些目标将定义人类 a 细胞的调节因子： 1. 确定调节人类 a 细胞功能的机制。为了对人类胰高血糖素分泌和调节进行前所未有的研究，我们生成了 NOD.Cg-Prkdc scidIl2rgtm1WjlSz 小鼠 (NSG)，其框内删除了编码胰高血糖素 1-29 的前胰高血糖素外显子 3；称为 GKO-NSG。这些小鼠可以对移植的人类α细胞中受调节的胰高血糖素分泌进行定量。体外和体内的遗传、生理和基因组方法将用于确定控制人类 a 细胞功能的机制。具体来说，我们将分析 a 细胞如何受到转录因子 MAFB 和 RFX6 的影响，我们的分析表明这些转录因子富含于独特的、功能活跃的细胞群中。 2. 研究脂滴在人类a细胞对脂毒性的适应性反应中的作用。脂毒性和伴随的胰岛素抵抗是人类糖尿病发病机制的既定风险。我们将使用遗传方法和体外和体内生理测定来确定控制脂滴（LD）（人类胰岛细胞器）积累的机制。这些研究将检验 LD 调节受到脂毒性和胰岛素抵抗挑战的人类 a 细胞功能的假设。这项工作使得我们能够对控制和调节人类 a 细胞的生理机制进行以前无法实现的研究。糖尿病和胰岛生物学研究的一个根本性进展是识别和表征导致糖尿病患者或有患糖尿病风险的胰岛细胞功能下降的因素。这里提出的研究应该揭示控制人类胰岛 a 细胞功能的机制。我们的工作应该建立将基因转录和细胞器调控与健康和患病胰岛中关键a细胞生理功能的控制联系起来的范例。适当调节胰岛 a 细胞功能是健康的一个重要特征，我们的工作将通过描述在正常和病理条件下改善胰岛 a 细胞功能的方法来产生广泛的影响。