Determining the Role of Notch Ligands in Regulating Adult Satellite Cell Fate

确定Notch配体在调节成体卫星细胞命运中的作用

• 批准号: 9204307
• 负责人: SUSAN ELIAZER
• 金额: $ 5.8万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2018-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9204307
• 关键词: Actins; Adult; Affect; Appearance; Basal lamina; Biological Assay; Cell membrane; Cell physiology; Cells; Complement; Coupled; Cytoplasm; Data; Daughter; Development; Dose; Enzymes; Fiber; Fostering; Gene Targeting; Health; Homeostasis; Human; Individual; Injury; Life; Ligands; Maintenance; Mediator of activation protein; Molecular; Mus; Muscle; Muscle Fibers; Muscle satellite cell; Myopathy; Natural regeneration; Nature; Notch Signaling Pathway; Organism; Outcome; Population; Regenerative response; Regulation; Role; Signal Transduction; Skeletal Muscle; Source; Specificity; Stem cells; Tamoxifen; Testing; Tissues; Up-Regulation; delta protein; exhaustion; gain of function; in vivo; insight; muscle aging; notch protein; novel therapeutic intervention; postnatal; premature; repaired; response to injury; satellite cell; skeletal; stem cell niche; ubiquitin-protein ligase

 DESCRIPTION (provided by applicant): Muscle stem cells, also called Satellite Cells (SC) function to maintain tissue homeostasis and regenerate skeletal muscle. In the adult, the SCs are maintained in a quiescent state both by intrinsic mechanisms and extrinsic signals from the niche. The quiescent nature of stem cells preserves the stem cell pool from premature exhaustion. One fundamental question is: how is the identity of the quiescent stem cells established and maintained during the life of an organism? And how the niche contributes to maintaining this identity? The notch signaling pathway is a major regulator of stem cell quiescence. In this proposal we aim to 1) identify the cell source and the specific Notch ligands that maintain SC quiescence and 2) how Notch signaling changes in the activated SCs. We will delete Mindbomb1, an enzyme that activates Notch ligands, specifically in the muscle fiber to determine the role of Notch ligands under homeostatic conditions and their impact on the ability of SCs to function under a regenerative response in vivo. We will also delete Dll4, a Notch ligand in the muscle fiber as preliminary data suggests that Dll4 expression increases in the muscle fiber during postnatal maturation which correlates with the appearance of quiescent SCs. Preliminary data also shows that activated SCs on an intact muscle fiber accumulate Dll4 in their cytoplasm; which is lost in the absence of muscle fibers. This suggests that muscle fiber is required for the increase in Dll4 protein in activated SC. We will assay the activated SC's on muscle fibers for Notch targets to see if there is a decrease in Notch signaling and will perform loss and gain-of-function for Dll4 in the activated SCs to see if Notch signaling is affected. The specific aims of this proposal are: 1) To determine the role of Notch ligands in the muscle fiber to maintain SC quiescence, 2) To determine if Dll4 is the critical mediator of Notch signaling that maintains SC quiescence and 3) To determine the functional role of Dll4 in activated satellite cell daughters. Successful completion of this project will provide molecular insights into the regulation of SC quiescence by the Notch ligands in the niche acting in a non-cell autonomous manner and how this transitions to cell-autonomous signaling in activated SCs.

 描述（由适用提供）：肌肉干细胞，也称为卫星细胞（SC），可维持组织稳态和再生骨骼肌。在成年人中，SC被通过固有机制和来自利基市场的外在信号保持在静止状态。干细胞的静态性质可保留干细胞库过早疲惫。一个基本问题是：在生物体生命中，如何建立和维护静止干细胞的身份？利基市场如何为维持这种身份做出贡献？ Notch信号通路是干细胞静止的主要调节剂。在此提案中，我们的目的是1）确定维持SC静止的细胞源和特定的缺口配体，以及2）notch信号如何在激活的SC中变化。我们将删除一种激活缺口配体的酶，尤其是在肌肉纤维中，以确定置于体内稳态条件下缺口配体的作用及其对体内再生反应下SCS功能功能的影响。我们还将删除DLL4，这是肌肉纤维中的一个缺口配体，因为初步数据表明，在产后成熟期间，肌肉纤维的DLL4表达增加，这与静态SC的出现相关。初步数据还表明，在其细胞质中积累了完整的肌肉纤维上的SCS。在没有肌肉纤维的情况下丢失了。这表明激活SC中DLL4蛋白增加需要肌肉纤维。我们将在Notch靶标上断言激活的SC在肌肉纤维上，以查看Notch信号的降低，并将对激活的SC中的DLL4执行损失和功能，以查看Notch信号是否影响。该提案的具体目的是：1）确定缺口配体在肌肉纤维中保持SC静止的作用，2）确定dll4是否是Notch信号的关键介体。 保持SC静止和3）确定DLL4在活化的卫星细胞女儿中的功能作用。该项目的成功完成将提供分子见解，以通过非单位自主性作用的notch配体调节SC静止，以及在激活的SC中如何向细胞自主信号转移。