Mechanisms of the cell non-autonomous dietary restriction pathway

项目概要/摘要 过去 25 年来，我们对衰老的分子和遗传机制的了解呈指数级增长。 年。对无脊椎动物模型（例如线虫秀丽隐杆线虫）的开创性研究已经 一直处于许多突破的前沿，包括发现第一个控制寿命的基因。 尽管有这些重要的研究，但衰老的遗传和分子机制有很多方面 仍然没有得到很好的理解。这些机制之一是细胞非自主控制衰老 生物体中的一小部分细胞（通常是神经元）。多个备受推崇的出版物 确定了信号通路起源处的单个基因和神经元，这些信号通路最终改变了遗传和 外周组织的代谢反应。这些研究提供了大量证据表明细胞非 衰老的自主控制是多种长寿途径的共同点，但缺乏具体细节 涉及信号、受体、神经回路和下游效应器。我们的初步数据表明 研究最充分的长寿干预措施，饮食限制（DR），部分通过非自主细胞发挥作用 线虫中受食物气味抑制的信号通路。我们进一步发现 DR 和禁食各 导致诱导肠道蛋白质，即含黄素的单加氧酶-2 (fmo-2)，这两者都是必需的 并足以改善健康寿命、抗压能力和寿命。我们还观察到 fmo-2 的诱导 和寿命的延长都依赖于血清素信号传导，并且可以通过血清素来概括 拮抗药，米安色林。该项目将绘制通过去除 最终导致肠道 fmo-2 诱导并延长寿命的食物。目标 1 将确定并 上位性地将参与该神经回路的神经元联系起来，回答关于哪些神经元的重要问题 特定细胞发起信号，哪些细胞传播信号，最终哪些细胞整合信号 信号转变为全系统响应。结果将定义一个由食物传感和利用主导的神经回路 血清素可能与其他长寿途径重叠。第二个目标将重点关注涉及的信号 通过识别小肽、突触运输进行神经元间和组织间通讯 机制以及参与该途径的受体。所得数据将填充神经回路模型 目标 1 涉及血清素以外的关键信号和受体，并可能导致未来的研究旨在 模仿/阻止这些信号。第三个目标将确定必要的主要受体和转录因子 在肠道中诱导 fmo-2。我们将使用正向遗传筛选、靶向 RNAi 方法以及现有的 ChIP-SEQ 数据定义了与 DR 介导的 fmo-2 诱导相关的主要肠道基因。在一起， 这些目标将独立和协同地发挥作用，以提供对主要信号网络的理解 改变衰老。我们的最终目标是利用衰老控制机制的知识来开发 促进人类健康的方法。

PROJECT SUMMARY/ABSTRACT Our understanding of the molecular and genetic mechanisms of aging has grown exponentially in the past 25 years. Groundbreaking studies in invertebrate models such as the nematode Caenorhabditis elegans have been at the forefront of many breakthroughs, including the discovery of the first genes that control longevity. Despite these important studies, there are many aspects of the genetic and molecular mechanisms of aging that are still not well understood. One of these mechanisms is the cell non-autonomous control of aging by small subsets of cells (frequently neurons) in an organism. Multiple highly regarded publications have identified individual genes and neurons at the origin of signaling pathways that eventually modify genetic and metabolic responses in peripheral tissues. These studies provide substantial evidence that cell non- autonomous control of aging is common to multiple longevity pathways, but they lack in detail as to the specific signals, receptors, neural circuits, and downstream effectors involved. Our preliminary data show that the most well-studied longevity intervention, dietary restriction (DR), acts in part through a cell non-autonomous signaling pathway that is inhibited by the smell of food in C. elegans. We further find that DR and fasting each lead to induction of an intestinal protein, flavin-containing monooxygenase-2 (fmo-2), that is both necessary and sufficient to improve healthspan, stress resistance, and longevity. We also observe that induction of fmo-2 and extension of lifespan both depend on the serotonergic signaling and can be recapitulated by the serotonin antagonist drug, mianserin. This project will map the cell non-autonomous pathway initiated by removal of food that eventually leads to intestinal fmo-2 induction and extension of lifespan. Aim 1 will identify and epistatically relate the neurons involved in this neural circuit, answering important questions about which specific cell(s) initiate the signal, which cell(s) propagate the signal, and ultimately, which cell(s) integrate the signal into a system-wide response. The results will define a neural circuit led by food sensing and utilizing serotonin that may overlap with other longevity pathways. The second aim will focus on the signals involved in inter-neuronal and tissue to tissue communication by identifying small peptides, synaptic transport mechanisms, and receptors involved in the pathway. The resulting data will fill out the neural circuit model from aim 1 with the key signals and receptors beyond serotonin, and could lead to future studies designed to mimic/block these signals. The third aim will identify the major receptors and transcription factors necessary to induce fmo-2 in the intestine. We will use a forward genetic screen, a targeted RNAi approach, and existing ChIP-SEQ data to define the major intestinal genes involved with DR-mediated fmo-2 induction. Together, these aims will act independently and synergistically to provide an understanding of a major signaling network that modifies aging. Our ultimate goal is to exploit this knowledge of control mechanisms of aging to develop approaches that promote human health.