Gating of Leptin Transport into the Cerebrospinal Fluid at the Choroid Plexus

瘦素转运至脉络丛脑脊液的门控

• 批准号: 10598456
• 负责人: Peter Nikolaevich Kalugin
• 金额: $ 3.96万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10598456
• 关键词: Acute; Adipocytes; Adipose tissue; Adult; Animals; Apical; Area; Binge Eating; Blood; Blood - brain barrier anatomy; Blood capillaries; Body Weight; Brain; Calcium; Central Nervous System; Cerebrospinal Fluid; Choroid Plexus Epithelium; Critical Pathways; Cues; Data; Disease; Dopamine; Eating; Endocrine; Endothelium; Energy Metabolism; Epithelial Cells; Epithelium; Exhibits; Fasting; Fatty acid glycerol esters; Feeding behaviors; Food; Food Intake Regulation; Genetic Polymorphism; Goals; High Fat Diet; Homeostasis; Hormones; Human; Image; Imaging Techniques; Impairment; Individual; Infusion procedures; Insulin Resistance; Knock-out; LDL-Receptor Related Protein 1; Label; Leptin; Leptin resistance; Lipoprotein Receptor; Liquid substance; Low Density Lipoprotein Receptor; Measures; Mediating; Metabolic; Metabolic Diseases; Methods; Molecular; Motivation; Mus; Neurons; Neurosecretory Systems; Obese Mice; Obesity; Pathway interactions; Peripheral; Phenotype; Plasma; Prediabetes syndrome; Process; Proteins; Regulation; Rewards; Role; Satiation; Serum; Signal Transduction; Structure of choroid plexus; Surface; Testing; Thinness; Time; Tropism; Ventral Tegmental Area; Viral Vector; Visualization; Wild Type Mouse; Work; awake; blood cerebrospinal fluid barrier; calcium indicator; design; dopaminergic neuron; experimental study; feeding; food consumption; gene therapy; glucose tolerance; in vivo; in vivo imaging; insight; insulin tolerance; median eminence; monolayer; neural; neural circuit; novel; novel therapeutic intervention; obesity development; obesity treatment; overexpression; receptor; response; tool; transcytosis; two-photon

Project Summary The central goal of this proposal is to elucidate how leptin transport into the cerebrospinal fluid (CSF) and brain is gated at the choroid plexus (ChP), how such gating influences the action of leptin on reward- related dopaminergic neurons, and how saturated ChP transport may contribute to leptin resistance in obesity. Regulation of energy expenditure and feeding are crucial to an animal’s ability to survive and maintain physiological homeostasis. Leptin is an endocrine factor secreted by adipocytes that participates in the regulation of food intake and body weight. Acting on receptors in the brain, leptin exerts an overall effect to decrease feeding, increase energy expenditure, and promote a lean phenotype. Leptin must enter the brain to reach its receptors. In obesity, circulating leptin levels are elevated, but the ratio of CSF to serum leptin is reduced, and leptin suppresses food intake when administered centrally but not peripherally. This suggests insufficient transport of leptin into the CSF as a potential contributor to the development of obesity. Preliminary work has implicated transcytosis through the blood-cerebrospinal fluid barrier of the ChP epithelium as a critical pathway of leptin entry into the brain. In fact, local deletion of endocytic receptor low density lipoprotein receptor-related protein 1 (LRP1) in the ChP epithelium impairs feeding suppression by peripheral leptin while keeping intact the decrease in food intake in response to centrally delivered leptin. However, the real time dynamics of this proposed transcytotic transport at the ChP are poorly understood. I propose to apply novel in vivo imaging techniques to study leptin transcytosis through the ChP epithelium as well as its access to and effects on leptin-sensitive dopaminergic circuitry in the ventral tegmental area (VTA) in real time in awake, behaving mice. In Aim 1, I will refine recently developed tools to visualize leptin transcytosis at the ChP in real time (see preliminary data) and quantitatively assess the effects of LRP1 deletion or overexpression on leptin transport from the blood into the CSF. Once it reaches the brain, leptin is known to engage a number of neural circuits. Dopaminergic neurons in the VTA encode the motivational salience of food and are normally inhibited by leptin, leading to reduced motivation for food consumption. In obesity, however, dysregulated VTA dopaminergic activity promotes compulsive eating. In Aim 2, I will extend the imaging toolkit to track the access of leptin to the VTA parenchyma in parallel with recording the activity of individual VTA dopaminergic neurons, and rigorously assess the interplay between leptin transcytosis at the ChP and the VTA dopaminergic responses to palatable food in lean and obese mice. Additionally, I will confirm if LRP1 overexpression in the ChP epithelium could be protective against the development of obesity. These studies will provide novel insights into the pathways and mechanisms of leptin entry into the brain, assess the dynamics and downstream effects of leptin signaling with unprecedented precision, and propose new therapeutic approaches for obesity and other metabolic disorders.

项目摘要 该提案的核心目标是阐明瘦素如何运输到脑脊液（CSF） 大脑在脉络丛（CHP）上门控，这种门控如何影响瘦素对奖励的作用 - 相关的多巴胺能神经元，以及饱和的CHP转运如何有助于瘦素耐药性 肥胖。能源消耗和喂养的调节对于动物生存和维护的能力至关重要 生理稳态。瘦素是参与该法规的脂肪细胞分泌的内分泌因子 食物摄入和体重。在大脑的受体上作用，瘦素会执行总体作用以减少 进食，增加能量消耗并促进瘦肉表型。瘦素必须进入大脑才能达到其 受体。在对象性方面，循环瘦素水平升高，但CSF与血清瘦素的比率降低，并且 瘦素在中央施用时抑制食物摄入量，但不会抑制外围。这表明不足 将瘦素运输到CSF中是肥胖发展的潜在贡献者。初步工作 通过CHP上皮的血经脊髓流体屏障作为关键途径暗示了脑胞症 瘦素进入大脑。实际上，内吞受体低密度脂蛋白受体相关的局部缺失 CHP上皮中的蛋白质1（LRP1）会损害周围瘦素的喂养抑制，同时保持完整 响应中央递送的瘦素而减少食物摄入量。但是，实时动态 建议在卫生卫生室中提议的跨细胞性转运知之甚少。我建议在体内成像应用小说 通过CHP上皮研究瘦素转胞细胞增多的技术及其获得和影响 在静脉片段区域（VTA）中实时的瘦素敏感性多巴胺能电路上， 行为小鼠。在AIM 1中，我将完善最近开发的工具，以可视化CHP的瘦素转胞细胞增多症 时间（请参阅初步数据），并定量评估LRP1缺失或过表达对瘦素的影响 从血液运输到CSF。一旦到达大脑，已知瘦素会与许多中性 电路。 VTA中的多巴胺能神经元编码食物的动机显着性，通常被抑制 通过瘦素，导致食物消费的动力减少。但是，在目标方面，VTA失调 多巴胺能活性促进强迫性饮食。在AIM 2中，我将扩展成像工具包以跟踪访问 与记录单个VTA多巴胺能神经元的活性并联的瘦素链球菌 并严格评估CHP的瘦素转胞细胞增多与VTA多巴胺能反应之间的相互作用 在瘦小和肥胖的小鼠中可口的食物。此外，我将确认CHP上皮中的LRP1过表达是否 可以保护免受肥胖的发展。这些研究将为您提供新的见解 瘦素进入大脑的途径和机制，评估瘦素的动力学和下游影响 以前所未有的精度发出信号，并提出针对肥胖和其他的新治疗方法 代谢障碍。