Plasmalemma permeability: A therapeutic target for traumatic brain injury?

描述（由申请人提供）：在神经保护领域，一个尚未解决的根本问题是创伤性损伤的脑细胞能否从死亡中获救。在创伤性脑损伤（TBI）模型中，诸如损伤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。质膜完整性丧失是实验性脑外伤中细胞损伤和死亡的共同特征。利用碘化丙啶（PI）在体内标记质膜完整性丧失的细胞，我们开发了一种PI脉冲标记方案，以跟踪小鼠控制性皮质撞击（CCI）后受损脑细胞的命运。我们的研究结果表明，尽管质膜完整性的丧失是许多细胞致命损伤的生物标志物，但有一部分PI+细胞可以通过适当的治疗药物来挽救。基于这些数据，我们提出了三个具体目标，以验证质膜完整性丧失是脑外伤后抢救损伤细胞的治疗靶点这一中心假设：目标1：验证受控皮质冲击后质膜完整性丧失的早期和晚期分别是致命损伤和可抢救损伤的生物标志物这一假设。目的2：通过体外和体内创伤模型以及缺乏TNF/Fas的小鼠或原代皮质神经元，验证质膜完整性丧失是一个由TNF α和Fas受体介导的活跃过程，该过程开始于TBI后的早期（几分钟）。目的3：验证质膜完整性恢复是CCI后创伤性脑细胞救治的治疗靶点。使用poloxamp188（一种非离子两亲性三嵌段共聚物膜重封剂）和坏死他汀-1（一种TNF/Fas诱导细胞死亡的特异性抑制剂）可减少小鼠CCI后质膜损伤和急性细胞死亡，并改善功能预后。提出的研究旨在表明，质膜完整性的丧失是TBI患者抢救损伤细胞的治疗靶点。这一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脑和脊髓损伤治疗剂潜在价值的工具，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.