Plasmalemma permeability: A therapeutic target for traumatic brain injury?

描述(申请人提供)：神经保护领域尚未解决的一个根本问题是，创伤损伤的脑细胞能否从死亡中拯救出来。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，以及最终死亡后的“不归点”等基本概念还没有得到充分的探索。质膜完整性的丧失是实验性颅脑损伤细胞损伤和死亡的共同特征。利用碘化丙啶(PI)标记体内细胞膜完整性丧失的细胞，我们建立了PI脉冲标记方案，以跟踪小鼠大脑皮质撞击(CCI)后受损脑细胞的命运。我们的发现表明，尽管在许多细胞中，质膜完整性的丧失是致命性损伤的生物标志物，但PI+细胞的一部分可能可以通过适当的治疗药物来挽救。基于这些数据，我们提出了三个特定的目标来检验中央假说，即质膜完整性的丧失是脑外伤后挽救受损细胞的治疗靶点：目的1：检验受控皮质撞击后早期和晚期质膜完整性丧失分别是致命性损伤和可挽救损伤的生物标志物的假设。目的：利用体外和体内创伤模型和小鼠或原代皮层神经元中缺乏肿瘤坏死因子/Fas的模型，验证损伤后早期(几分钟)起，细胞膜完整性丧失是由肿瘤坏死因子α和Fas受体介导的活跃过程的假说。目的：验证质膜完整性的恢复是CCI后创伤损伤脑细胞的治疗靶点的假说。使用非离子两亲性三嵌段共聚物膜再封闭剂泊洛沙姆P188和肿瘤坏死因子/Fas诱导的细胞死亡的特异性抑制剂Necrostatin-1，可以减少细胞膜损伤和急性细胞死亡，改善小鼠CCI后的功能结局。建议的研究旨在表明，质膜完整性的丧失是挽救脑外伤患者受损细胞的一个治疗靶点。这个拟议项目的工作可能会通过开发一种治疗创伤性脑损伤的新方法，以及通过开发工具来帮助研究人员更好地评估脑和脊髓损伤治疗剂的潜在价值，从而影响公众健康。

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.