Traumatic brain injury: early mechanosensitive events in astrocytes

摘要 创伤性脑损伤（TBI）是由外部机械力引起的脑损伤，例如 如爆炸或撞击。我们目前对TBI的理解主要来自体内研究， 显示出对TBI后取样的细胞的可测量的生物效应。关于初选的情况知之甚少 机械应力在脑细胞在破坏性刺激，以及它们是如何被转换成 细胞和分子事件参与TBI。这项提议旨在研究什么样的刺激措施 性质对细胞损伤以及机械刺激如何与细胞损伤耦合是最关键的。 次生细胞突起我们将使用组织培养的成年星形胶质细胞在微流体 由快速压力伺服驱动的腔室，以产生时间相关的流体剪切， 用来模拟爆炸产生的剪切应力我们将直接测量具体的应力 使用基因编码的荧光应力传感器的细胞骨架蛋白。这项研究 两个具体目标。目标1确定了刺激的物理特性，导致长期 改变。通过测量特定细胞骨架蛋白中应力的时程， 各种振幅、上升时间和频率的冲击波，我们将确定参数 导致不可逆变形。这种不可逆性将通过调查确定 解剖结构和应力分布的变化。目的2研究细胞的反应， 以确定机械刺激如何改变细胞 体内平衡为此，我们将测量细胞内Ca2+和细胞内Ca2+浓度的时间依赖性变化。 音量.这些特性将与细胞应力同时测量，以确定 因果关系我们将进一步测试机械敏感性通道在通过Ca2+中的作用， 特异性抑制剂，GsMTx4，并探讨是否预先给予GsMTx4可用作 预防性治疗

Abstract Traumatic brain injury (TBI) is brain damage resulting from an external mechanical force, such as blast or crashes. Our current understanding of TBI is derived mainly from in vivo studies that show measurable biological effects on cells sampled after TBI. Little is known about the primary mechanical stresses in brain cells during damaging stimuli, and how they are transduced into cellular and molecular events involved in TBI. This proposal aims to examine what stimulus properties are most critical to cell injury and how the mechanical stimulus is coupled to secondary cellular processes. We will use tissue cultured adult astrocytes in a microfluidic chamber driven by a fast pressure servo to generate time dependent fluid shear that can be made to emulate shear stress from a blast. We will directly measure the stresses in specific cytoskeletal proteins using genetically encoded fluorescent stress sensors. The research has two specific aims. Aim 1 identifies physical properties of the stimulus that lead to long term alterations. By measuring the time course of stresses in specific cytoskeletal proteins using shockwaves of various amplitude, rise time, and frequency, we will determine the parameters that lead to irreversible deformation. This irreversibility will be determined by investigating changes in anatomy and stress distribution. Aim 2 investigates the cells' response during and immediately after mechanical insult to determine how mechanical stimulus alters cell homeostasis. For this we will measure the time dependent changes of intracellular Ca2+ and cell volume. These properties will be measured simultaneously with cellular stress to determine causality. We will further test the role of mechanosensitive channels for passing Ca2+ using specific inhibitor, GsMTx4, and explore whether pre-administration of GsMTx4 might be used as a preventive therapy.