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（由申请人提供）：迄今为止，操纵下丘脑功能主要依赖于有条件的基因敲除小鼠或转基因过表达。这些方法的主要局限性是，它们没有考虑到神经内分泌神经元及其预测的发展以及在早期生命中操纵这些神经元时发生的补偿性适应性的复杂性。或者，递送siRNA的腺相关病毒（AAV）的显微注射已用于修改成年后的下丘脑功能。该技术的最大限制是该过程的侵入性和相对效率低下。目前的应用旨在通过开发一种新颖的，微创的方法来规避这些局限性，以时期定义和细胞特异性方式操纵下丘脑神经元功能。在可以用作这些研究原型的下丘脑系统中，弧形核（ARC）的黑色皮质素系统是理想的候选者。通过调节食物摄入量，体重和葡萄糖稳态来调节能量平衡，已经对其进行了广泛的研究，并显示出在调节能量平衡中起关键作用。它由两个具有相反功能的神经元组成。含有促蛋白酶素（POMC）的神经元抑制了饮食和刺激能量消耗的动力，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。可以通过测量食物摄入和体重来可靠地评估改变任何神经元子集功能的后果。从人类健康的角度来看，开发研究该系统的新工具具有巨大的价值。早期营养改变导致的童年和成年肥胖症的急剧增加使得迫切需要开发新的方法，以更好地了解喂养行为和能量稳态控制的基础机制。这是一个特别重要的问题，因为能量平衡可能会受到在人类在妊娠晚期和啮齿动物期间的关键时期发生的“发展计划”的营养挑战的永久影响。我们建议开发的技术的一个主要优点是，在能源平衡的发展编程完成后，它可用于修改ARC功能。我们建议通过通过血管内给予用于转导下丘脑细胞的修饰的AAV2颗粒，通过将RNA干扰（RNAI）递送到ARC中来静音POMC和AGRP基因。我们预计，这些研究的成功执行将为治疗神经内分泌脑疾病的类似方法的最终应用铺平道路。我们还预计，这些研究将为基础研究目的和新兴疗法提供新的交付策略的基础。 公共卫生相关性：该应用建议开发一种新型方法来操纵神经内分泌大脑中的基因表达。这种方法基于通过修饰病毒进行了血管内递送，该病毒设计为向下丘脑表现出对流。可以预料，该策略将为产生神经内分泌疾病的动物模型并尝试对下丘脑疾病的治疗干预提供宝贵的工具。