Characterization of EGCG-receptors: Role in mediating the effects of green tea

EGCG 受体的表征：在调节绿茶作用中的作用

• 批准号: 7331848
• 负责人: Mark Lundquist
• 金额: $ 4.1万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7331848
• 关键词: Antibodies; Apoptosis; Apoptotic; Axon; Binding Proteins; Biological Assay; Cell Line; Cells; Consumption; Dietary Supplementation; Disease; Epigallocatechin Gallate; Genes; Green tea; Growth Cones; Health Benefit; Hippocampus (Brain); Knock-out; LAMR1 gene; Malignant Neoplasms; Mediating; Modeling; Molecular; Neurodegenerative Disorders; Neurons; Pathogenesis; Phenocopy; Physiological; Protein Overexpression; Proteins; Rattus; Reagent; Role; Safety; Semaphorin-3A; Signal Transduction; Signaling Molecule; Small Interfering RNA; Spinal cord injury; Squalene monooxygenase; Subfamily lentivirinae; Traumatic Nerve Injury; cancer type; excitotoxicity; gallocatechol; knock-down; nerve injury; nervous system disorder; neuron loss; neuroprotection; prevent; protein function; receptor; research study; tool

DESCRIPTION (provided by applicant): (-)-Epigallocatechin-3-gallate (EGCG) is a component of green tea, a widely used herbal remedy. Green tea has been consumed for its health benefits for thousands of years, yet the molecular mechanism by which EGCG mediates its effects is not fully understood. EGCG has been intensively studied for its anti-cancer effects. EGCG inhibits the proliferation and induces apoptosis in many types of cancer lines. Several EGCG-binding proteins have been identified, and a subset of these has been shown to mediate the pro- apoptotic effects of EGCG in different cell lines. However, EGCG also has potent and potentially medically useful effects on neurons. EGCG prevents neuronal cell death in various models of neurodegenerative disease as well as in excitotoxicity models. Additionally, EGCG is able to inhibit the effects of certain molecules, such as Semaphorin 3A (SemaSA), that promote axonal retraction. This effect could make EGCG useful as a CAM for disorders such as spinal cord injury or other traumatic nerve injuries. However, it is unknown if the receptors that mediate the antiapoptotic effects of EGCG also mediate the effects of EGCG on neurons. Alternatively, other EGCG-proteins, such as squalene monooxygenase, MICAL, or 67LR might mediate the effects of EGCG in neurons. To identify the mechanisms by which EGCG mediates its effects in neurons, the specific aims of this proposal are: (1) To develop reagents and assay candidate EGCG receptors for neuroprotection. In this aim, I describe experiments to ascertain if siRNA-mediated knockdown of the putative EGCG receptors phenocopies the effect of EGCG treatment in an assay for neuronal excitotoxicity using cultured rat hippocampal neurons; and (2) To determine whether candidate EGCG receptors mediate the effects of EGCG on axons. In this aim, I describe experiments using knockout and overexpression strategies to determine if known EGCG-binding proteins mediate the ability of EGCG to block SemaSA signaling in axons. Together, the experiments in these two aims will clarify whether the putative EGCG receptors mediate the well-documented actions of EGCG in neurons. Because of the widespread consumption of EGCG, the identification of biologically relevant EGCG receptors is important for understanding the mechanism of action, appropriateness, and safety of EGCG dietary supplementation. Additionally, the identification of biologically relevant receptors for the actions of EGCG in neurons will help to clarify the suitability of EGCG as a CAM for neurological diseases and disorders associated with nerve injury.

（-）-表没食子儿茶素-3-没食子酸酯（EGCG）是绿茶的一种成分，是一种广泛使用的草药。几千年来，人们一直饮用绿茶，因为它对健康有益，但EGCG介导其作用的分子机制尚不完全清楚。EGCG因其抗癌作用而被广泛研究。EGCG在多种类型的癌细胞中具有抑制增殖和诱导凋亡的作用。已经鉴定了几种EGCG结合蛋白，其中的一个子集已被证明在不同细胞系中介导EGCG的促凋亡作用。然而，EGCG对神经元也有强大的潜在医学作用。EGCG在各种神经退行性疾病模型以及兴奋性毒性模型中防止神经元细胞死亡。此外，EGCG能够抑制某些分子的作用，如信号蛋白3A (SemaSA)，促进轴突收缩。这种作用使EGCG可以作为脊髓损伤或其他创伤性神经损伤等疾病的辅助诊断药物。然而，目前尚不清楚介导EGCG抗凋亡作用的受体是否也介导EGCG对神经元的作用。另外，其他EGCG蛋白，如角鲨烯单加氧酶、micical或67LR可能介导EGCG在神经元中的作用。为了确定EGCG在神经元中的作用机制，本提案的具体目标是：(1)开发用于神经保护的EGCG候选受体的试剂和检测。为此，我描述了一些实验，以确定在使用培养的大鼠海马神经元进行神经元兴奋性毒性试验时，sirna介导的EGCG受体的敲除是否反映了EGCG治疗的效果；(2)确定候选EGCG受体是否介导EGCG对轴突的作用。在这个目的中，我描述了使用敲除和过表达策略的实验，以确定是否已知的EGCG结合蛋白介导EGCG阻断轴突SemaSA信号的能力。总之，这两个目的的实验将澄清假设的EGCG受体是否介导EGCG在神经元中的充分记录的作用。由于EGCG的广泛消费，鉴定与EGCG生物学相关的受体对于了解EGCG膳食补充的作用机制、适宜性和安全性非常重要。此外，确定EGCG在神经元中作用的生物学相关受体将有助于阐明EGCG作为神经系统疾病和与神经损伤相关的疾病的CAM的适用性。