Plasmalemma permeability: A therapeutic target for traumatic brain injury?

描述（由申请人提供）：神经保护领域的一个尚未解决的基本问题是创伤性损伤的脑细胞是否可以从死亡中拯救出来。在创伤性脑损伤（TBI）模型中，诸如受损细胞的存活时间和功能以及最终死亡的“不归点”等基本概念尚未得到充分探讨。质膜完整性的丧失是实验性TBI中细胞损伤和死亡的共同特征。利用碘化丙啶（PI）标记细胞与质膜完整性的损失在体内，我们开发了PI脉冲标记协议，以跟踪小鼠受控皮质撞击（CCI）后受损脑细胞的命运。我们的研究结果表明，虽然质膜完整性的丧失是许多细胞中致命损伤的生物标志物，但PI+细胞的一个亚群可能是可通过适当的治疗剂挽救的。基于这些数据，我们提出了三个具体目标来测试中心假设，即质膜完整性的丧失是TBI后挽救受损细胞的治疗靶点：目标1：测试以下假设：在受控皮质撞击后，质膜完整性的早期与晚期丧失分别是致命性损伤与可挽救损伤的生物标志物。目标二：使用体外和体内创伤模型以及TNF/Fas缺陷的小鼠或原代皮质神经元，检验质膜完整性丧失是TBI后早期（数分钟）开始的TNF α和Fas受体介导的主动过程这一假设。目的3：验证假设，即恢复质膜完整性是CCI后挽救创伤性损伤脑细胞的治疗靶点。使用泊洛沙姆P188（一种非离子型两亲性三嵌段共聚物膜再密封剂）和坏死抑素-1（一种TNF/Fas诱导细胞死亡的特异性抑制剂），以减少小鼠CCI后的质膜损伤和急性细胞死亡，并改善功能结局。拟议的研究旨在表明质膜完整性的丧失是拯救TBI患者受损细胞的治疗靶点。这项拟议项目的工作可以通过开发创伤性脑损伤的新治疗方法，以及开发可以帮助研究人员更好地评估治疗药物对脑和脊髓损伤的潜在价值的工具来影响公共卫生。

DESCRIPTION (provided by applicant): A fundamental problem in the neuroprotection field that remains unsolved is whether or not traumatically injured brain cells can be rescued from death. Essential concepts such as survival time and functionality of injured cells, and the "point of no return" from eventual demise have not been adequately explored in traumatic brain injury (TBI) models. Loss of plasmalemma integrity is a common feature of cellular injury and death in experimental TBI. Using propidium iodide (PI) to label cells with loss of plasmalemma integrity in vivo, we developed a PI pulse labeling protocol to follow the fate of injured brain cells after controlled cortical impact (CCI) in mice. Our findings suggest that although loss of plasmalemma integrity is a biomarker of fatal injury in many cells, a subset of PI+ cells may be rescuable by appropriate therapeutic agents. Based on these data, we propose three Specific Aims to test the central hypothesis that loss of plasmalemma integrity is a therapeutic target to rescue injured cells after TBI: Aim 1: Test the hypothesis that loss of plasmalemma integrity early versus late following controlled cortical impact is a biomarker of fatal versus rescuable injury, respectively. Aim 2: Test the hypothesis that loss of plasmalemma integrity is an active process mediated by TNF alpha and Fas receptors beginning early (minutes) after TBI, using in vitro and in vivo trauma models and mice or primary cortical neurons deficient in TNF/Fas. Aim 3: Test the hypothesis that restoration of plasmalemma integrity is a therapeutic target to rescue traumatically injured brain cells after CCI. Use poloxamer P188, a non-ionic amphiphilic triblock copolymer membrane resealing agent, and necrostatin-1, a specific inhibitor of TNF/Fas induced cell death, to reduce plasmalemma damage and acute cell death and improve functional outcome after CCI in mice. The proposed studies are intended to show that loss of plasmalemma integrity is a therapeutic target to rescue injured cells in patients with TBI. Work in this proposed project could impact public health by developing a new treatment for traumatic brain injury, and by developing tools that could assist researchers to better assess the potential value of therapeutic agents for brain and spinal cord injuries.