Identifying new genes involved in thymic involution

鉴定参与胸腺退化的新基因

• 批准号: 10092939
• 负责人: Nancy R Manley
• 金额: $ 18.88万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10092939
• 关键词: Adult; Affect; Age; Aging; Biochemical; Bioinformatics; Birth; Candidate Disease Gene; Cell Compartmentation; Cell Maturation; Cells; Development; Down-Regulation; Enhancers; Ethylnitrosourea; Funding; Gene Expression; Generations; Genes; Genetic; Genetic Screening; Genotype; Homeostasis; Human; Immune; Immune system; Individual; Lead; Maintenance; Mediating; Messenger RNA; Modeling; Molecular; Morphology; Mouse Strains; Mus; Mutagenesis; Mutation; Nature; Organ; Organogenesis; Pathway interactions; Pattern; Phenotype; Pilot Projects; Process; Production; Regulation; Resources; Role; Scanning; Severities; Signal Transduction; Specificity; T-Cell Development; T-Lymphocyte; Testing; Thymic epithelial cell; Thymus Gland; Youth; adaptive immunity; aged; base; causal variant; cell type; design; exome sequencing; experimental study; follow-up; functional decline; immune function; immunosenescence; improved; mouse genome; mutant; normal aging; novel; novel strategies; novel therapeutic intervention; postnatal; premature; prevent; tool; transcription factor

Project Summary/Abstract The thymus is the primary immune organ responsible for the generation of T cells, and its functional decline with age (involution) is considered a significant contributor to aging-associated immunosenescence. There is strong evidence that aging-related thymic involution is initiated during youth by mechanisms that operate in thymic epithelial cells (TECs) to result in their depletion and loss of compartmental organization. Despite its central role in the formation and maintenance of T cell adaptive immunity and the pleiotropic negative impacts of thymus involution during aging, surprisingly few molecular regulators of thymus organ function, homeostasis, and involution have been identified. A key transcription factor, FOXN1, is known to be a primary regulator of both thymus development and postnatal maintenance. However, the mechanisms of its regulation and the pathways through which it affects TEC development, function, and aging-related involution remain largely unknown. TECs are a small subset of total thymus cells and are notoriously difficult to isolate experimentally. Thus, identifying regulators and effectors by gene expression-based or biochemical analysis is difficult, and in any case would be specifically targeted to a TEC subset or specific age. Given the gradual nature of thymic involution, designing such experiments to identify key regulators of thymus function and maintenance with aging would be doubly challenging. Forward genetic screens are powerful tools for identifying genes based on their function, thus allowing unbiased discovery of novel pathways and mechanisms, but are not generally practical for aging-related phenotypes. In a recent R21-funded project, my lab performed a dominant modifier screen using ENU mutagenesis to identify novel mutations that, when heterozygous, either enhance (increase the severity) or suppress (rescue/reduce the severity) the Foxn1Z/Z thymic involution phenotype. We identified 18 dominant modifier lines, including both enhancers and suppressors. Because they impact Foxn1 expression and/or function in the Foxn1Z/Z model of premature thymic involution, our hypothesis is that these modifiers represent previously unrecognized genes that normally act to promote or restrain aging-related thymic involution. In the current proposal, we will follow up on our successful initial project to identify the modifiers found in our pilot screen, and test whether they affect the trajectory of involution during normal aging. This novel approach to investigating the molecular basis of thymus involution represents a potentially transformative approach to identifying new genes, pathways, and mechanisms that control thymus function and aging-related involution.

项目概要/摘要 胸腺是负责产生 T 细胞的主要免疫器官，其功能随着时间的推移而下降 年龄（退化）被认为是与衰老相关的免疫衰老的重要因素。有很强的 有证据表明，与衰老相关的胸腺退化是在青年时期通过胸腺中运作的机制启动的 上皮细胞（TEC），导致其耗竭和区室组织丧失。尽管其核心作用 T 细胞适应性免疫的形成和维持以及胸腺的多效性负面影响 衰老过程中的退化，令人惊讶的是胸腺器官功能、体内平衡和代谢的分子调节剂很少 内卷已被识别。已知关键转录因子 FOXN1 是两者的主要调节因子 胸腺发育和产后维持。但其调控机制和途径 它通过何种方式影响 TEC 的发育、功能和衰老相关的退化仍然很大程度上未知。 TEC 是总胸腺细胞的一小部分，并且众所周知难以通过实验分离。因此，识别 通过基于基因表达或生化分析来调节调节子和效应子是很困难的，并且在任何情况下都会 专门针对 TEC 子集或特定年龄。鉴于胸腺退化的渐进性，设计 此类实验旨在确定胸腺功能和衰老维持的关键调节因子，这将是双倍的 具有挑战性的。正向遗传筛选是根据功能识别基因的强大工具，因此 允许公正地发现新的途径和机制，但通常不适用于与衰老相关的 表型。在最近的 R21 资助的项目中，我的实验室使用 ENU 进行了显性修饰筛选 诱变来识别新的突变，当杂合时，这些突变要么增强（增加严重性）要么 抑制（拯救/降低严重程度）Foxn1Z/Z 胸腺退化表型。我们确定了 18 个主要 修饰线，包括增强子和抑制子。因为它们影响 Foxn1 表达和/或 胸腺过早退化的 Foxn1Z/Z 模型中的功能，我们的假设是这些修饰符代表 以前未被识别的基因通常会促进或抑制与衰老相关的胸腺退化。在 目前的提案，我们将跟进我们成功的初始项目，以确定在我们的试点中发现的修饰符 筛选，并测试它们是否影响正常老化过程中的复旧轨迹。这种新颖的方法 研究胸腺退化的分子基础代表了一种潜在的变革性方法 识别控制胸腺功能和衰老相关退化的新基因、途径和机制。