Chemogenetic control of liver metabolism

肝脏代谢的化学遗传学控制

• 批准号: RGPIN-2020-05508
• 负责人: Caron, Alexandre
• 金额: $ 2.7万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762035
• 关键词: Chemogenetic; control; liver; metabolism

Hepatic glucose production (HGP) is the result of coordinated biochemical processes by which glycogen storage are catabolized to generate glucose (glycogenolysis), or glucose is produced from non-carbohydrate carbon substrates (gluconeogenesis). These processes are regulated by many G protein coupled receptors (GPCRs) expressed at the surface of the hepatocytes. As their names imply, GPCRs interact with G proteins located in the plasma membrane. When a ligand binds to the GPCR, it causes a conformational change that triggers the interaction between the GPCR and a nearby G protein. However, the downstream signaling events mediating the effects of GPCR activation on HPG are still misunderstood because of the lack of appropriate tools to selectively stimulate G proteins acutely. Here, I propose to harness the power of chemogenetics to selectively manipulate GPCR signaling in hepatocytes, as a mean of defining the complex biochemical reactions leading to HGP. Chemical genetics (chemogenetics) is an approach use to genetically engineer receptors that interact with previously unrecognized small molecule chemical actuators. This approach has been used to create modified GPCRs, called Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). Originally developed to control neuronal activity, DREADDs are emerging as key tools for selective pharmacological control of GPCR signaling in any cell type or organ. Recently, I reported the generation of a novel chemogenetic approach allowing acute stimulation of GsPCR and GiPCR signaling in adipocytes. This innovative model revealed important, previously unappreciated complex interactions of GPCR signaling in adipose tissue and demonstrated the usefulness of chemogenetic technology to better understand organ functions. I propose to combine state-of-the-art metabolic flux techniques with chemogenetics models to better understand the mechanisms mediating HGP. In particular, I propose to use chemogenetics to dissect two important metabolic pathways for HGP, namely glycogenolysis and gluconeogenesis in vitro (primary hepatocytes), ex vivo (perfused livers) and in vivo. Building on my previous work and expertise on liver metabolism and chemogenetic technology, this program aims to: 1) determine the sex-dependent mechanisms by which chemogenetic stimulation of liver GqPCR stimulate HGP; 2) evaluate how GqPCR signaling affects metabolic flux independent of changes in peripheral hormones in a perfused mouse liver model; 3) define the molecular cascade leading to HGP in primary hepatocytes. This Discovery Grant will define complex previously unknown mechanisms mediating HGP. Understanding this biology will provide a framework to better understand how different systems directly regulates liver metabolism. This program will also provide a powerful and sought after scientific and technical skill set for my students and the field to understand other regulatory factors involved in peripheral metabolism.

肝葡萄糖产生（HGP）是协调的生化过程的结果，通过该生化过程，糖原储存被分解代谢以产生葡萄糖（糖原分解），或者葡萄糖由非碳水化合物碳底物产生（糖原生成）。这些过程由肝细胞表面表达的许多G蛋白偶联受体（GPCR）调节。顾名思义，GPCR与位于质膜上的G蛋白相互作用。当配体与GPCR结合时，它会引起构象变化，从而触发GPCR与附近G蛋白之间的相互作用。然而，由于缺乏合适的工具来选择性地刺激G蛋白，介导GPCR激活对HPG影响的下游信号事件仍然被误解。在这里，我建议利用化学遗传学的力量来选择性地操纵肝细胞中的GPCR信号，作为定义导致HGP的复杂生化反应的一种手段。化学遗传学（chemogenetics）是一种用于遗传工程受体的方法，这些受体与以前未被识别的小分子化学致动器相互作用。这种方法已被用于创建修改的GPCR，称为设计师受体专门激活的设计师药物（DREADD）。DREADD最初是为了控制神经元活动而开发的，现在正成为选择性药理学控制任何细胞类型或器官中GPCR信号传导的关键工具。最近，我报道了一种新的化学发生方法的产生，允许急性刺激脂肪细胞中的GsPCR和GiPCR信号传导。这一创新模型揭示了脂肪组织中GPCR信号传导的重要的、以前未被重视的复杂相互作用，并证明了化学遗传学技术在更好地理解器官功能方面的有用性。我建议将联合收割机最先进的代谢通量技术与化学遗传学模型相结合，以更好地了解介导HGP的机制。特别是，我建议使用化学遗传学来解剖两个重要的代谢途径，即糖原分解和糖原异生在体外（原代肝细胞），离体（灌注肝脏）和体内。基于我以前在肝脏代谢和化学遗传学技术方面的工作和专业知识，该计划旨在：1）确定肝脏GqPCR的化学遗传学刺激刺激HGP的性别依赖性机制; 2）评估GqPCR信号传导如何影响灌注小鼠肝脏模型中不依赖于外周激素变化的代谢通量; 3）定义原代肝细胞中导致HGP的分子级联。这项发现基金将定义复杂的以前未知的机制介导人类基因组蛋白。了解这种生物学将提供一个框架，以更好地了解不同的系统如何直接调节肝脏代谢。该计划还将为我的学生和该领域提供强大的和受欢迎的科学和技术技能，以了解参与外周代谢的其他调节因素。