Negative feedback regulation of growth factor signaling in adult spermatogonial stem cells

成体精原干细胞生长因子信号传导的负反馈调节

• 批准号: 10570919
• 负责人: Todd R Evans
• 金额: $ 36.44万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10570919
• 关键词: Ablation; Address; Adult; Biochemical; Biosensor; Cell Culture System; Cells; Clone Cells; DUSP6 protein; Data; Equilibrium; FGF2 gene; Feedback; Fibroblast Growth Factor; Future; Gene Family; Genes; Genetic; Genetic Diseases; Genetic Transcription; Genetically Engineered Mouse; Germ Cells; Goals; Growth; Growth Factor; Growth Factor Receptors; Hyperactivity; Image; Impairment; In Vitro; Infertility; Kinetics; Laboratories; MAP Kinase Gene; Mammals; Measurement; Methodology; Molecular; Mus; Outcome; Pathway interactions; Phenotype; Physiological; Population; Process; Production; Recovery; Regulation; Reporter; Role; Series; Signal Induction; Signal Transduction; Specificity; Spermatogonia; Stem cell transplant; Structure; System; Testing; Testis; Time; Translating; Transplantation; Up-Regulation; Work; experimental study; glial cell-line derived neurotrophic factor; improved; in vivo; member; mouse model; novel; preservation; prevent; real time monitoring; response; self-renewal; single-cell RNA sequencing; sperm cell; stem cell biomarkers; stem cell differentiation; stem cell function; stem cell niche; stem cell self renewal; stem cells; therapeutic target

Abstract Niche-derived growth factors (GFs) are essential for establishing and maintaining mammalian spermatogonial stem cells (SSCs) in the adult testis. In culture, however, optimal conditions for expansion of pure populations of self-renewing SSCs remain elusive. We recently found that mouse SSCs possess unexpectedly robust mechanisms to counter-regulate GF signaling by inducing expression of negative feedback regulators (NFRs), including members of the Spry and Dusp gene families. Abrogation of specific NFRs in SSCs led to increase ERK signaling, decreased expression of stem cell-associated genes in vitro and loss of stem cell activity upon transplantation, suggesting that excessive GF-dependent signaling is detrimental to SSC function and may favor differentiation. The cellular alterations that occur following perturbation of NFRs are unknown. However, our data imply that SSCs are programmed to limit ERK signaling within a narrow physiological range. This proposal addresses the mechanisms by which NFRs restrict GF signaling in SSCs, prevent unscheduled differentiation, and enable long-term propagation of SSC clones. Using genetic mouse models, SSC culture, transplantation analysis, and a newly-developed real-time biosensor for ERK activity, we address the following questions: (1) Which NFRs are required for SSC self-renewal? (2) How does ablation of NFRs result in loss of stem cell activity? (3) How do NFRs control the dynamic intracellular signaling cascades downstream of GF receptors? And (4) At which nodes in the ERK pathway do NFRs exert their actions? In addition to providing a rational basis to improve SSC culture systems, these studies will also identify novel adult SSC markers and shed light on mechanisms by which cross-talk between the niche and SSCs balances self-renewal and differentiation in vivo.

抽象的 生态位衍生生长因子 (GF) 对于建立和维持哺乳动物的生存至关重要 成人睾丸中的精原干细胞（SSC）。然而，在文化中，最佳条件 自我更新的SSCs纯种群的扩张仍然难以实现。我们最近发现 小鼠 SSC 具有出乎意料的强大机制，可以通过以下方式反调节 GF 信号传导： 诱导负反馈调节因子 (NFR) 的表达，包括 Spry 的成员 和 Dusp 基因家族。 SSC 中特定 NFR 的废除导致 ERK 信号传导增加， 干细胞相关基因的体外表达减少以及干细胞活性丧失 移植，表明过度的 GF 依赖性信号传导对 SSC 有害 功能并可能有利于分化。扰动后发生的细胞变化 NFR 的数量未知。然而，我们的数据表明 SSC 被编程为限制 ERK 在狭窄的生理范围内发出信号。该提案通过以下方式解决了这些机制 哪些 NFR 限制 SSC 中的 GF 信号传导，防止非计划分化，并使 SSC克隆的长期繁殖。使用遗传小鼠模型、SSC 培养、 移植分析，以及新开发的 ERK 活性实时生物传感器，我们 解决以下问题： (1) SSC 自我更新需要哪些 NFR？ (2) 如何 NFR 的消融会导致干细胞活性丧失吗？ (3) NFR如何控制动态 细胞内信号级联下游的 GF 受体？ (4) 位于哪些节点 NFRs通过ERK途径发挥作用吗？除了提供合理的改进依据 SSC 培养系统，这些研究还将鉴定新型成人 SSC 标记并揭示 生态位和 SSC 之间的串扰平衡自我更新和 体内分化。