Altering Energy Balance by Systemic Delivery of RNAi to the Neuroendocrine Brain

通过将 RNAi 系统性递送至神经内分泌脑来改变能量平衡

• 批准号: 8427058
• 负责人: Sergio R Ojeda
• 金额: $ 26.73万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8427058
• 关键词: Accounting; Adrenal Glands; Adult; Affect; Animal Model; Animals; Basic Science; Binding; Body Composition; Body Weight; Brain; Brain Stem; Capsid; Cells; Childhood; Dependovirus; Development; Disease; Eating; Energy Metabolism; Engineering; Epitopes; Feeding behaviors; Gene Expression; Genes; Goals; Health; Home environment; Homeostasis; Human; Hypothalamic Diseases; Hypothalamic structure; Injection of therapeutic agent; Knockout Mice; Libraries; Life; Measures; Methods; MicroRNAs; Microinjections; Neuroendocrine Cell; Neurons; Neurosecretory Systems; Nutritional; Obesity; Peptides; Peripheral; Phage Display; Pituitary Gland; Play; Population; Pregnancy; Pro-Opiomelanocortin; Procedures; RNA Interference; Rattus; Reading; Regulation; Relative (related person); Rodent; Role; Site; Specificity; Structure; Structure of nucleus infundibularis hypothalami; System; Techniques; Technology; Testing; Therapeutic Intervention; Transgenic Organisms; Tropism; Viral; Virus; adeno-associated viral vector; base; blood glucose regulation; cell type; cellular transduction; critical developmental period; energy balance; heparin proteoglycan; in vivo; interest; knock-down; minimally invasive; neuropeptide Y; novel; novel strategies; overexpression; particle; postnatal; programs; prototype; receptor; tool

DESCRIPTION (provided by applicant): To date, manipulating hypothalamic function mostly relies on the use of conditional knockout mice or transgenic overexpression. The major limitation to these approaches is that they do not take into account the complexities in the development of neuroendocrine neurons and their projections, and the compensatory adaptations that occur when these neurons are manipulated during early life. Alternatively, microinjections of adeno-associated viruses (AAV) delivering siRNAs have been used to modify hypothalamic function in adulthood. The greatest limitation of this technique is the invasiveness and relative inefficiency of the procedure. The present application intends to circumvent these limitations by developing a novel, minimally invasive method to manipulate hypothalamic neuronal function in a temporally defined and cell-specific manner. Among the hypothalamic systems that can be used as a prototype for these studies, the melanocortin system of the arcuate nucleus (ARC) stands out as an ideal candidate. It has been extensively studied and shown to play a critical role in regulating energy balance through modulation of food intake, body weight and glucose homeostasis. It is composed of two major populations of neurons with opposite functions; neurons containing pro-opiomelanocortin (POMC) inhibit the drive to eat and stimulate energy expenditure, neurons containing neuropeptide Y/Agouti-related peptide (NPY/AgRP) stimulate feeding behavior and inhibit energy expenditure. The consequences of altering the functions of either neuronal subset can be reliably assessed non-invasively, by measuring food intake and body weight. From the human health standpoint, developing new tools to study this system has an enormous value; the dramatic increase in childhood and adult obesity resulting from nutritional alterations during early life makes it urgent to develop novel methods to better understand the central mechanisms underlying the control of feeding behavior and energy homeostasis. This is a particularly important issue because energy balance can be permanently affected by nutritional challenges taking place during the critical period of "developmental programming" that in humans occurs during late gestation and in rodents, during the early postnatal period. A major advantage of the technology we propose to develop is that it can be used to modify ARC function after the developmental programming of energy balance is complete. We propose to silence the POMC and AgRP genes by delivering RNA interference (RNAi) to the ARC via the intravascular administration of modified AAV2 particles engineered to transduce hypothalamic cells. We anticipate that the successful execution of these studies will pave the way to the eventual application of similar approaches to treat disorders of the neuroendocrine brain. We also anticipate that these studies will provide the basis for new delivery strategies to the brain for basic research purposes and emerging therapies. PUBLIC HEALTH RELEVANCE: This application proposes to develop a novel approach to manipulate gene expression in the neuroendocrine brain. This approach is based on the intravascular delivery of RNAi via modified viruses engineered to display tropism for the hypothalamus. It is anticipated that this strategy will provide an invaluable tool to generate animal models of neuroendocrine disorders and to attempt therapeutic intervention of hypothalamic disease.

描述（申请人提供）：迄今为止，操纵下丘脑功能主要依赖于使用条件敲除小鼠或转基因过表达。这些方法的主要限制是，它们没有考虑神经内分泌神经元发育及其投射的复杂性，以及这些神经元在生命早期被操纵时发生的补偿性适应。另外，显微注射腺相关病毒 (AAV) 传递 siRNA 已被用来改变成年期的下丘脑功能。该技术的最大限制是手术的侵入性和相对低效。本申请旨在通过开发一种新颖的、微创的方法来以时间限定的和细胞特异性的方式操纵下丘脑神经元功能，从而规避这些限制。在可用作这些研究原型的下丘脑系统中，弓状核（ARC）的黑皮质素系统脱颖而出，成为理想的候选者。它已被广泛研究并证明通过调节食物摄入、体重和葡萄糖稳态在调节能量平衡中发挥关键作用。它由功能相反的两个主要神经元群组成；含有阿片黑皮素原 (POMC) 的神经元抑制进食欲望并刺激能量消耗，含有神经肽 Y/Agouti 相关肽 (NPY/AgRP) 的神经元刺激进食行为并抑制能量消耗。通过测量食物摄入量和体重，可以以非侵入性方式可靠地评估改变任一神经元子集功能的后果。从人类健康的角度来看，开发新工具来研究该系统具有巨大的价值；由于生命早期的营养改变导致儿童和成人肥胖症急剧增加，因此迫切需要开发新方法来更好地了解控制摄食行为和能量稳态的核心机制。这是一个特别重要的问题，因为能量平衡可能会受到“发育规划”关键时期发生的营养挑战的永久影响，“发育规划”的关键时期发生在人类妊娠晚期和啮齿动物出生后早期。我们建议开发的技术的一个主要优点是，在能量平衡的开发编程完成后，它可以用来修改ARC功能。我们建议通过血管内施用经过改造的 AAV2 颗粒（设计用于转导下丘脑细胞）向 ARC 传递 RNA 干扰 (RNAi)，从而沉默 POMC 和 AgRP 基因。我们预计这些研究的成功执行将为最终应用类似方法治疗大脑神经内分泌疾病铺平道路。我们还预计这些研究将为基础研究目的和新兴疗法的新大脑递送策略提供基础。 公共健康相关性：本申请提出开发一种新方法来操纵神经内分泌脑中的基因表达。该方法基于通过经过改造的病毒进行血管内RNAi递送，该病毒被设计为显示出对下丘脑的趋向性。预计该策略将为生成神经内分泌疾病的动物模型并尝试下丘脑疾病的治疗干预提供宝贵的工具。