Investigating the Forces that Transduce Mechanical Cues to Branching Neurons

神经元是神经的基本细胞，是疾病或损伤后最难再生的细胞之一。如果要在支持神经再生和再生的工程系统方面取得进展，我们必须充分了解这些细胞如何对其生物力学环境做出反应。这项研究将研究细胞外机械环境的变化如何影响神经元的发育和树突的分支--树突是接收来自其他神经细胞的信号的结构。从这个项目中获得的知识将有助于制定最终可能改进退行性神经疾病或因创伤造成的神经损伤后的治疗的策略。研究团队将把从研究生院到高中的所有级别的学生以及教师都纳入到该项目中。此外，外展将包括开发实践项目和演示，向公众介绍神经科学、成像和生物力学的概念。在这个项目中，与神经元生长和发育有关的两个假说正在进行研究。第一种是与施加细胞力相关的局部结构变化，将细胞外的机械信号传递给细胞骨架。第二，细胞张力的局部变化响应于细胞外机械微环境的变化，将细胞外机械信号传递给细胞骨架。研究小组将利用纽氏力传感器，其张力可以通过福斯特共振能量转移(FRET)来测量。这种机械测量将与细胞骨架动力学的荧光成像相结合。因此，该项目的具体目标是：1)证明纽球蛋白的表达随底物硬度和张力的变化而变化；2)证明纽球蛋白张力随着底物硬度的变化而改变，并研究整合素、钙粘附素和神经递质受体在调节这种反应中的作用；以及3)调查纽球蛋白张力、微管组装和由此产生的树突分支之间的关系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Neurons, the basic cells of nerves, are one of the most difficult to regenerate after disease or injury. If advances are going to be made in engineering systems that support nerve regrowth and regeneration, it is imperative that we develop a full understanding of how these cells respond to their biomechanical environment. This study will investigate how changes in the extracellular mechanical environment affects the development of neurons and the branching of dendrite -- the structure that receives signals from other nerve cells. Knowledge gained from this project will help to develop strategies that may eventually improve treatments for degenerative neural diseases or following nerve injury due to trauma. The research team will integrate students at all levels, from graduate school through high school, as well as teachers into the project. In addition, outreach will involve the development of hands-on projects and demonstrations that can introduce the public to concepts of neuroscience, imaging, and biomechanics. Two hypotheses are being investigated related to neuron growth and development within this project. The first is that local structural changes associated with applied cell forces act to transduce extracellular mechanical cues to the cytoskeleton. The second is that local changes in cellular tension in response to changes in the extracellular mechanical microenvironment act to transduce extracellular mechanical cues to the cytoskeleton. The research team will make use of a vinculin force sensor for which the tension can be measured using Forster resonance energy transfer (FRET). This mechanical measurement will be combined with fluorescence imaging of the cytoskeletal dynamics. Thus, the specific aims of this project are to: 1) demonstrate that vinculin expression changes as a function of substrate stiffness and tension; 2) demonstrate that vinculin tension is altered in response to changes in substrate stiffness and investigate the role of integrin, cadherin, and neurotransmitter receptors in mediating this response; and 3) investigate the relationship between vinculin tension, microtubule assembly, and the resulting dendritic branching.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.