Notch and Wnt signaling in protection by nandrolone against disuse atrophy

Notch 和 Wnt 信号传导在诺龙防止废用性萎缩中的保护作用

• 批准号: 8202501
• 负责人: CHRISTOPHER P CARDOZO
• 金额: --
• 依托单位: JAMES J PETERS VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8202501
• 关键词: Adult; Affect; Androgen Receptor; Androgen Response Element; Animal Model; Asthma; Atrophic; Binding; Binding Sites; Burn injury; Cell Culture Techniques; Cell Nucleus; Cell physiology; Cells; Chronic Obstructive Airway Disease; Commit; Communities; DNA; DNA Binding; DNA Sequence; Data; Denervation; Disease; Disuse Atrophy; Event; Fiber; Future; Gene Expression; Genes; Genetic Transcription; Hypertrophy; Immobilization; Immunohistochemistry; Injury; Knock-out; Knowledge; Ligand Binding; Ligands; Mediating; Medical; Mesenchymal Stem Cells; Messenger RNA; Molecular; Muscle; Muscle Fibers; Muscular Atrophy; Myoblasts; Nandrolone; Nerve; Nuclear Translocation; Paralysed; Pharmaceutical Preparations; Play; Proliferating; Proteolysis; Quality of life; Recovery; Response Elements; Role; Sequence Analysis; Signal Transduction; Site; Skeletal Muscle; Soldier; Speed; Spinal cord injury; Stroke; TCF Transcription Factor; Testing; Time; Transgenic Mice; Up-Regulation; Veterans; activating transcription factor; cell type; daughter cell; functional restoration; improved; inhibitor/antagonist; mRNA Stability; mouse model; muscle form; notch protein; overexpression; prevent; promoter; receptor; research study; restoration; satellite cell; self-renewal; tissue repair; transcription factor

DESCRIPTION (provided by applicant): The current proposal grew from studies of the molecular mechanisms by which nandrolone protects against muscle atrophy caused by nerve transection and were stimulated by findings that Notch and Wnt play critical roles in tissue repair after muscle injury. Notch stimulates proliferation of satellite cells, a mesenchymal 'stem' cell capable of proliferating to allow self-renewal, and of producing daughter cells able to commit to the skeletal muscle lineage, form myoblasts, and fuse to form new muscle fibers or contribute to existing ones. Wnt inhibits Notch signaling and stimulates myogenic differentiation. Our preliminary data suggest that denervation activates Notch and Wnt signaling in denervated muscle and that nandrolone terminates Notch signaling while further increasing Wnt signaling. Termination of Notch signaling by nandrolone is associated with increased expression of the Notch inhibitor Numb. A preliminary analysis of the sequence of the Numb promotor suggests that it contains binding sites for transcription factors (TCF/LEF) by which Wnts regulate gene expression through activation and nuclear translocation of the transcriptional regulator ss-catenin, as well as possible androgen receptor response elements; the androgen receptor is a ligand-activated transcription factor that binds to such sites to upregulate gene expression. Our hypothesis is that nandrolone induces upregulation of Numb and Wnt signaling in satellite cells, which is critical to protection against atrophy by nandrolone, and dependent upon upregulation of Numb transcription; upregulation is mediated by the androgen receptor and Wnt signaling. The following specific aims are proposed: 1. Determine the cell type(s) in which nandrolone alters Numb, and signaling by Notch and ss- catenin. Our hypothesis is that nandrolone regulates Numb expression and Notch and ss-catenin- dependent signaling in satellite cells and that effects of nandrolone on Numb expression and ss-catenin- dependent signaling occur in the same cells. In a mouse model of denervation atrophy, we will determine the cell type in which nandrolone upregulates Numb and signaling by ss-catenin by immunohistochemistry. 2. Examine the role of Numb in nandrolone-induced inhibition of Notch signaling and protection against denervation atrophy. Our hypothesis is that upregulation of Numb terminates Notch signaling and is necessary for effects of nandrolone to protect against denervation atrophy. We will use a transgenic mouse in which the Numb gene can be inactivated at a specific time. Experiments will test whether inactivation of the Numb gene blocks effects of nandrolone on Notch signaling and protection against muscle atrophy in a mouse model of denervation atrophy. 3. Characterize molecular mechanisms by which nandrolone upregulates Numb. Our hypothesis is that the Numb promotor contains a cluster of androgen response elements, and thus upregulation of Numb by nandrolone requires binding of the androgen receptor to these DNA sequences. In animal models, we will test the role for Wnt signaling in Numb expression in denervated muscle by either knocking out ss-catenin or overexpressing Wnts or their inhibitors. In cell culture, we will determine whether: binding of nandrolone to the androgen receptor (AR) is needed for upregulation of Numb by nandrolone; AREs within the Numb promotor function to upregulate its transcription; and nandrolone alters Numb mRNA stability.

描述（由申请人提供）： 目前的提议来自对分子机制的研究，通过这种机制，nandrolone可以预防由神经横断引起的肌肉萎缩，并通过发现缺口和Wnt在肌肉损伤后在组织修复中起关键作用的发现而刺激了肌肉萎缩。 Notch刺激了卫星细胞的增殖，一种能够增殖以自我更新的间充质“干式”细胞，并产生能够致力于骨骼肌谱系的子细胞，形成肌细胞，形成肌细胞，以及形成新的肌肉纤维或对现有肌肉形成新的肌肉纤维。 WNT抑制Notch信号传导并刺激肌源分化。我们的初步数据表明，神经网络神经肌肉中的Notch和Wnt信号传导，Nandrolone终止了Notch信号传导，同时进一步增加了Wnt信号传导。 Nandrolone对Notch信号的终止与Notch抑制剂麻木的表达增加有关。对麻木启动子的序列的初步分析表明，它包含转录因子（TCF/LEF）的结合位点，WNTS通过转录调节剂SS-Catenin的激活和核转运以及可能的雄激素受体响应元件来调节基因表达；雄激素受体是一种结合此类位点的配体激活转录因子，以上调基因表达。我们的假设是，nandrolone诱导了卫星细胞中麻木和Wnt信号传导的上调，这对于nandrolone的保护至关重要，并且取决于麻木转录的上调。上调是由雄激素受体和Wnt信号传导介导的。提出了以下特定目的：1。确定nandrolone会改变麻木的细胞类型，并通过Notch和Ss-Catenin发出信号。我们的假设是，nandrolone调节卫星细胞中的Numb表达，Notch和SS-Catenin-依赖性信号传导，以及Nandrolone对Numb表达和SS-Catenin--依赖性信号的影响发生在同一细胞中。在小鼠神经萎缩的模型中，我们将确定nandrolone通过免疫组织化学通过SS-catenin上调Numb和信号传导的细胞类型。 2。检查麻木在nandrolone诱导的Notch信号传导抑制和防止神经萎缩的保护中的作用。我们的假设是，麻木的上调端子信号传导，对于nandrolone的影响以防止去神经萎缩。我们将使用转基因小鼠，其中麻木基因在特定时间可能被灭活。实验将测试麻木基因的失活是否阻断nandrolone对凹槽信号传导的影响，并在小鼠神经萎缩模型中对肌肉萎缩进行保护。 3。表征nandrolone上调麻木的分子机制。我们的假设是，麻木的启动子包含雄激素反应元件的簇，因此nandrolone对麻木的上调需要雄激素受体与这些DNA序列的结合。在动物模型中，我们将通过敲除SS-catenin或过表达的WNT或其抑制剂来测试Wnt信号在Numb表达中的作用。在细胞培养中，我们将确定是否需要：Nandrolone上调Numb需要：Nandrolone与雄激素受体（AR）的结合；麻木启动子功能中的ARE上调其转录； Nandrolone改变了麻木的mRNA稳定性。