Genetic analysis of adult germline stem cell maintenance and homing

成体生殖干细胞维持和归巢的遗传分析

• 批准号: 8595016
• 负责人: Adam Langenbacher
• 金额: $ 5.22万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8595016
• 关键词: Address; Adult; Animal Model; Animals; Antibodies; Candidate Disease Gene; Cell Count; Cell Maintenance; Cell Survival; Cell physiology; Cells; Characteristics; Chordata; Data; Defect; Development; Disease; Ensure; Environment; Exhibits; Failure; Fertility; Foundations; Gene Expression; Gene Expression Profile; Genes; Genetic; Germ Cells; Germ cell tumor; Gonadal structure; Health; Home environment; Homing; Homologous Gene; Human; Individual; Infertility; Injury; Intercellular Junctions; Laboratories; Life; Life Cycle Stages; Ligands; Location; Longevity; Maintenance; Malignant Neoplasms; Marines; Meiosis; Modeling; Natural regeneration; Oocytes; Organ; Organism; Pathway interactions; Patients; Phase; Play; Population; Process; Proliferating; Regenerative Medicine; Reproduction; Reproductive Medicine; Research; Role; Signal Transduction; Site; Somatic Cell; Staging; Stem cells; Testing; Tissues; Transplantation; Undifferentiated; Work; aldehyde dehydrogenases; asexual; base; egg; gene function; genetic analysis; loss of function; migration; next generation; parasitism; public health relevance; receptor; reproductive; self-renewal; sperm cell; stem cell biology; stem cell population; success; tissue regeneration

DESCRIPTION (provided by applicant): Germline stem cells (GSCs) are critical for reproduction, retaining the capacity to differentiate into gametes and pass genetic information on to the next generation. GSCs depend on both intrinsic and extrinsic signals to home to their niche, maintain potency, and begin meiotic division to differentiate into gametes. Botryllus schlosseri is a marine chordate with several characteristics that make it a useful and attractive model for elucidating the mechanisms of GSC biology. (1) First, adult Botryllus can cycle through phases of fertility and infertility, while continuously maintaining a population of GSCs. By comparing the whole transcriptomes of fertile and infertile Botryllus adults, we have identified a Tgf¿ ligand, Tgf¿-f, upregulated in fertile animals that is expressed by follicle and follicle-progenitor cells both inside and outside of the gonadal niche. Tgf¿-f is also simultaneously upregulated in oocyte follicle cells and downregulated in testicular follicle cells during maturatin of the gonads. I hypothesize that Tgf¿-f and Tgf¿ signaling may play a role in the maintenance, homing, and differentiation of Botryllus GSCs, and I will test this hypothesis in Aim 1 of this proposal by examining these processes in Tgf¿ loss of function animals. (2) Second, Botryllus exhibits a phenomenon called germ cell parasitism (gcp) in which a colony may fuse to a neighbor and replace its germline by the transfer of GSCs, and this can be recapitulated by experimental transplantation of a FACS-enriched stem cell population. Colonies that successfully replace the germline of their fusion partner are referred to as "winners" while those whose germlines are replaced are referred to as "losers." I hypothesize that the phenomenon of gcp is produced by differences between individuals in the ability of their GSCs to proliferate and home to the germ cell niche. I further hypothesize that these differences are present at the level of gene expression or function within GSCs. I will test this hypothesis in Aim 2 of this proposal by FACS-isolating GSCs from gcp winners and losers and comparing their transcriptomes to identify genes and pathways associated with gcp success or failure. Dysregulation of GSCs can severly impact human health by leading to germ cell tumors or infertility. The broad questions being addressed in this proposed study are what mechanisms exist to ensure that GSCs home effectively to their target niche and once there, how they are maintained in an undifferentiated state in the adult organism. Answering these questions will lay the foundation for therapies in reproductive and regenerative medicine.

描述(申请人提供)：生殖系干细胞(GSCs)对生殖至关重要，它保留了分化为配子并将遗传信息传递给下一代的能力。GSCs依赖于内在和外在的信号来定位它们的生态位，维持活力，并开始减数分裂分化成配子。Schlosseri Botryllus schlosseri是一种海洋脊索动物，具有多种特性，使其成为阐明GSC生物学机制的有用和有吸引力的模型。(1)首先，成年Botryllus可以循环通过生育和不育阶段，同时持续维持GSCs的数量。通过比较可育和不育的Botryllus成虫的全部转录本，我们已经确定 一种转化生长因子配体，转化生长因子-f，在有生育能力的动物体内表达，由性腺巢内外的卵泡和卵泡祖细胞表达。在性腺成熟过程中，转化生长因子-f在卵泡细胞中表达上调，在睾丸滤泡细胞中表达下调。我假设转化生长因子-f和转化生长因子信号可能在Botryllus GSCs的维持、归巢和分化中发挥作用，我将通过研究转化生长因子功能丧失动物的这些过程来检验这一假设。(2)其次，Botryllus表现出一种称为生殖细胞寄生(GCP)的现象，在这种现象中，一个群体可以与邻近的群体融合，并通过转移GSCs来取代其生殖系，这可以通过实验移植富含FACS的干细胞群体来概括。成功替代其融合伙伴的生殖系的菌落被称为“赢家”，而那些其种系被替代的被称为“输家”。我假设GCP现象是由于个体之间的GSC增殖能力的差异以及生殖细胞生态位的存在而产生的。我进一步假设，这些差异存在于GSC内的基因表达或功能水平上。我将在这项提议的目标2中通过FACS验证这一假设-从GCP成功者和失败者中分离GSC，并比较他们的转录本，以确定与GCP成功或失败相关的基因和途径。GSCs的失调会导致生殖细胞肿瘤或不育，从而严重影响人类健康。这项拟议的研究涉及的广泛问题是，存在哪些机制来确保GSC有效地定位于其目标生态位，以及一旦到达目标生态位，它们如何在成年生物体中保持未分化状态。回答这些问题将为生殖和再生医学的治疗奠定基础。