Engineering a Neural Tissue Model of Oligodendroglial and Matrix Remodeling after Biophysical Injury

大脑中的细胞驻留在一个三维矩阵中，该矩阵控制着它们的命运和功能。这些细胞包括神经元和少突胶质细胞，前者在其长轴突上上下快速发送信号，后者在轴突上沉积一层名为髓鞘的绝缘鞘。这种髓鞘类似于电线上的绝缘体，因此对于正常的功能是必不可少的。机械力对大脑的损伤，如冲击伤，会损害脑细胞，并经常导致髓鞘丢失以及少突胶质细胞和神经元的死亡。为了开发修复这种损伤的方法，首先需要了解与髓鞘生成和破坏(分别是髓鞘形成和脱髓鞘)有关的机制。由于少突胶质细胞既不是简单地出现在大脑中，也不是一成不变地留在那里，因此了解祖细胞(早期的未分化细胞)是如何成为成熟的少突胶质细胞也是很重要的。该项目的主要目标是创造一个可调节的3D环境，支持少突胶质前体细胞(OPC)的生长、轴突生长和髓鞘的产生，然后了解工程组织机械损伤后的退化过程。3D环境将包括传统2D培养中不存在的细胞-细胞和细胞-基质环境的重要方面。通过该项目计划的外展和教育目标将大大提高人们对工程学在卫生领域的作用的兴趣，使不同类型的小学生感兴趣，并为社会经济困难的学生提供通过付费大学研究机会攻读STEM相关领域的手段。私人投资机构将继续指导其研究小组中代表性不足的本科生，特别是女性。最后，PI将创造一个新的机会来促进研究生：教师交流和职业指导这个项目包括三个研究目标。首先是确定培养基质的机械性能支持前体细胞分化为成熟少突胶质细胞的机制，然后优化该体系。这将考虑神经干细胞向OPC的分化以及OPC向成熟的、产生髓鞘的少突胶质细胞的分化。第二个目标将集中在3D培养中支持少突胶质细胞产生髓鞘的结构线索，这在2D培养中没有观察到。最后，具有分化的少突胶质细胞的优化系统将通过可控的冲击室暴露于压力冲击波。将评估表征细胞响应性阈值以及机械转导机制和表型变化的机械参数的多尺度测量。这将通过2D和3D培养来确定细胞环境的差异对脱髓鞘过程的影响。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。

Cells in the brain reside in a three-dimensional matrix that regulates their fate and function. These include neurons, which quickly send signals up and down their long axons, and oligodendrocytes, which deposit an insulating sheath, called myelin, on the axons. This myelin is analogous to insulation on a wire, and thus essential for proper function. Injuries to the brain from mechanical forces, like blast injury, damage brain cells and frequently lead to loss of myelin along with death of oligodendrocytes and neurons. In order to develop ways to repair this damage, it is first necessary to understand the mechanisms connected to myelin creation and destruction (myelination and demyelination, respectively). As oligodendrocytes neither simply appear in the brain nor remain there without changing, it is also important to understand how progenitor cells (earlier, undifferentiated cells) become mature oligodendrocytes. This project's primary goals are to create a tunable, 3D environment that will support oligodendrocyte progenitor cell (OPC) growth, axon growth, and production of myelin, and then to understand the degenerative process after mechanical injury to the engineered tissue. The 3D environment will include important aspects of the cell-cell and cell-matrix environment that are not present in traditional 2D culture. The outreach and education objectives planned through this project will significantly expand interest in the role of engineering in health fields to broadly diverse elementary school children and provide means for socioeconomically challenged students to pursue STEM related fields through paid college research opportunities. The PIs will continue to mentor underrepresented undergraduate students, particularly women, in their research groups. Finally, the PI will create a new opportunity to facilitate graduate student:faculty communication and career mentoringThis project includes three research aims. The first is to determine the mechanism through which the mechanical properties of the culture matrix will support differentiation of precursor cells into mature oligodendrocytes, and then to optimize this system. This will take into account differentiation of neural stem cells to OPCs as well as differentiation of OPCs to mature, myelin producing oligodendrocytes. The second aim will focus on structural cues in 3D culture to support myelin production by the oligodendrocytes, which is not observed in 2D culture. Finally, the optimized system with differentiated oligodendrocytes will be exposed to pressure blast waves through a controllable blast chamber. Multiscale measurements of mechanical parameters that characterize the cell responsivity threshold as well as mechanotransduction mechanisms and phenotypic changes will be assessed. This will be done with both 2D and 3D culture to identify the effect of differences in the cellular environment on the demyelination process.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.