Regulation of Synaptic Morphology by Growth Factors

生长因子对突触形态的调节

• 批准号: 6826447
• 负责人: RANDALL S WALIKONIS
• 金额: $ 26.59万
• 依托单位: UNIVERSITY OF CONNECTICUT STORRS
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-04 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6826447
• 关键词: NMDA receptors; SDS polyacrylamide gel electrophoresis; biological signal transduction; confocal scanning microscopy; electron microscopy; enzyme linked immunosorbent assay; glutamate receptor; green fluorescent proteins; hepatocyte growth factor; immunocytochemistry; immunoelectron microscopy; laboratory rat; molecular shape; morphology; nerve /myelin protein; neural plasticity; neural transmission; phosphorylation; protein structure function; protein tyrosine kinase; synapses; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Regulation of the strength of synaptic transmission is postulated to play a critical role in processing and storage of information in the brain. Structural and functional modifications of the synapse contribute to changes in strength of transmission. However, the biochemical mechanisms that regulate synaptic plasticity remain poorly understood. Various growth factors have been shown to influence synaptic structure and function, but many of the downstream effects of the signals they induce have not been identified. Our long-term objective is to understand the molecular signals initiated by growth factors at synapses, and identify how these signals regulate synaptic structure as it relates to learning and memory. We have strong Preliminary Data that demonstrates that the receptor protein tyrosine kinase Met and its ligand, hepatocyte growth factor (HGF), are clustered at excitatory synapses in hippocampal neurons. We demonstrate that neuronal activity leads to release of HGF and activation of Met. Met is known to influence many aspects of cellular morphology, and we show that exogenous HGF increases the clustering of presynaptic and postsynaptic proteins at synapses, increases the expression of synaptic proteins, and initiates acute and long-term changes in neurons. This proposal represents an initial step in characterizing the regulation of synaptic biochemistry by hepatocyte growth factor and Met. In the first aim, the subcellular location of Met and HGF will be identified to determine whether these signaling molecules operate at the presynaptic or postsynaptic membrane, and whether HGF is located in vesicles that undergo regulated secretion. In the second aim, the secretion of HGF in response to pharmacological activation of synaptic activity will be quantified and mechanisms regulating its release will be identified. The third aim is to test the acute effects of HGF on synapses with the use of live-cell imaging and biochemical studies. In the fourth aim, the signaling pathways initiated by HGF and Met to regulate glutamate receptor trafficking will be identified. These studies will provide the basis for further studies on the mechanisms by which Met regulates synaptic structure.

描述（由申请人提供）： 假设突触传播强度的调节在大脑中信息的处理和存储中起关键作用。突触的结构和功能修饰有助于传播强度的变化。然而，调节突触可塑性的生化机制仍然很少理解。已经显示出各种生长因子会影响突触结构和功能，但是尚未鉴定出诱导信号的许多下游效应。我们的长期目标是了解突触时生长因子发起的分子信号，并确定这些信号如何调节与学习和记忆有关的突触结构。我们有强大的初步数据，表明受体蛋白酪氨酸激酶及其配体肝细胞生长因子（HGF）被聚集在海马神经元中的兴奋性突触下。我们证明神经元活性导致HGF释放和MET的激活。已知MET会影响细胞形态的许多方面，我们表明外源HGF会增加突触下突触前和突触后蛋白的聚类，增加突触蛋白的表达，并启动神经元的急性和长期变化。该提案代表了通过肝细胞生长因子和MET来表征突触生物化学调节的第一步。在第一个目的中，将确定MET和HGF的亚细胞位置，以确定这些信号分子是否在突触前或突触后膜上进行，以及HGF是否位于受调节分泌的囊泡中。在第二个目标中，将量化HGF对突触活性的药理激活的分泌，并确定调节其释放的机制。第三个目的是通过使用活细胞成像和生化研究来测试HGF对突触的急性影响。在第四个目标中，将确定由HGF和MET启动以调节谷氨酸受体运输的信号传导途径。这些研究将为进一步研究MET调节突触结构的机制提供基础。