SGER: Does Re-expression of Vimentin Induce Resumption of Axonal Elongation?

SGER：波形蛋白的重新表达是否会诱导轴突伸长的恢复？

• 批准号: 0331066
• 负责人: Thomas Shea
• 金额: $ 6.39万
• 依托单位: University of Massachusetts Lowell Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0331066&HistoricalAwards=false
• 关键词: SGER; Does; Re; expression; Vimentin

Neurons, extend long processes called axons, that act essentially as telephone wires and transmit the signals that allow us to think, feel and move. During embryonic development, axons elongate at a rapid rate, connecting nerve cells and muscles. Once an axon reaches its target, however, it stops elongating and stabilizes its structure, since its task is now to remain connected for the lifetime of the individual. The axon is supported internally by a series of fibrous structures collectively referred to as the cytoskeleton (that is, the skeleton of the cell). Dr. Shea's laboratory has shown that the rapid elongation during development is mediated by a protein called vimentin, that forms pliable filaments that rapidly assemble and disassemble. Once the neuron reaches its target, however, it stops producing vimentin, and replaces it with a different group of proteins called neurofilaments. Neurofilaments make fibers that cross link and bind together, and form a stabilized matrix that supports the now fully-grown axon. Unfortunately, should an axon die or be severed, the portion that is connected to the neuron is unable to start growing again to allow reconnection to its previous target. The PI has studied these events in neuroblastoma cells; a cell line, due to ease of manipulation and cost-effectiveness. Their early observations indicated a developmental heirarchy in intermediate filaments (IFs). Vimentin (Vm) is the predominant IF species during axonal initiation. During axonal elongation, Vm expression ceases and neurons express neurofilament (NF) proteins, which increase axonal caliber and stabilize the developing axon. Dr. Shea's laboratory has demonstrated by intracellular delivery of neutralizing antibodies and antisense oligonucleotides that Vm is essential for axon initiation but is dispensable once the axon has formed; conversely, NFs are not required for axonal initiation but are essential for axonal stabilization. The PI proposes to examine further this phenomenon in motor neurons (neurons that connect to and stimulate muscle cells) grown outside the body, to determine whether or not we can induce axons to start growing again and whether or not such axons stop growing when they reach their targets. Dr. Shea's laboratory is proficient in all of the required methodologies, and this project will provide rich training opportunities for graduate and undergraduate students.

神经元，延伸出长长的轴突，本质上就像电话线一样，传递信号，让我们思考，感觉和移动。 在胚胎发育期间，轴突以快速的速度伸长，连接神经细胞和肌肉。 然而，一旦轴突到达其目标，它就会停止伸长并稳定其结构，因为它的任务是在个体的一生中保持连接。 轴突在内部由一系列统称为细胞骨架（即细胞骨架）的纤维结构支撑。 Shea博士的实验室已经表明，发育过程中的快速伸长是由一种叫做波形蛋白的蛋白质介导的，这种蛋白质形成了柔韧的细丝，可以快速组装和分解。 然而，一旦神经元到达其目标，它就停止产生波形蛋白，取而代之的是一组不同的蛋白质，称为神经丝。 神经丝形成纤维，这些纤维交叉连接并结合在一起，形成稳定的基质，支持现在完全生长的轴突。 不幸的是，如果轴突死亡或被切断，连接到神经元的部分无法再次开始生长，以允许重新连接到其先前的目标。 PI已经在神经母细胞瘤细胞中研究了这些事件;由于易于操作和成本效益，细胞系。他们早期的观察表明，中间纤维（IF）的发育层次结构。波形蛋白（Vm）是轴突起始过程中的主要IF种类。 在轴突伸长过程中，Vm表达停止，神经元表达神经丝（NF）蛋白，其增加轴突口径并稳定发育中的轴突。 Shea博士的实验室已经通过细胞内递送中和抗体和反义寡核苷酸证明，Vm对于轴突起始是必需的，但是一旦轴突形成，Vm就被抑制;相反，NF对于轴突起始不是必需的，但是对于轴突稳定是必需的。 PI建议在体外生长的运动神经元（连接并刺激肌肉细胞的神经元）中进一步研究这种现象，以确定我们是否可以诱导轴突重新开始生长，以及这些轴突是否在到达目标时停止生长。 Shea博士的实验室精通所有所需的方法，该项目将为研究生和本科生提供丰富的培训机会。