Transport of neurotrophic cytokines after spinal cord injury

脊髓损伤后神经营养细胞因子的转运

• 批准号: 7022220
• 负责人: Weihong Pan
• 金额: $ 23.24万
• 依托单位: LSU PENNINGTON BIOMEDICAL RESEARCH CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022220
• 关键词: behavior test; blood brain barrier; cytokine; cytokine receptors; epidermal growth factor; laboratory mouse; leukemia inhibitory factor; membrane permeability; methylprednisolone; nervous system disorder chemotherapy; nervous system regeneration; neuronal transport; neurotrophic factors; nonhuman therapy evaluation; radiotracer; receptor expression; receptor mediated endocytosis; spinal cord injury; transcytosis

Adequate neurotrophic support is essential for spinal cord regeneration; however, production of neurotrophins and neurotrophic cytokines at the site of spinal cord injury (SCI) is insufficient. The blood-brain/blood-spinal cord barrier (BBB/BSCB) mediates permeation of selective neurotrophic cytokines from the periphery. We propose that the transport system for leukemia inhibitory factor (LIF) at the BSCB is upregulated after SCI, and that enhanced transport of LIF benefits functional recovery. To test the hypothesis that LIF crosses the BSCB by receptor-related transport and that the transport system is upregulated after SCI, we will measure blood-to-spinal cord transfer of 12SI-LIF, test the effects of different classes of transport inhibitors, and compare the results with that of epidermal growth factor (125I-EGF). We expect that 12SI-LIF entry will be decreased by a LIF receptor antibody whereas 12SI-EGF entry will be decreased by polycationic peptides and dansylcadaverin but not by an EGF receptor antibody. This will support the concept that LIF crosses the BSCB by receptor-mediated transport while EGF does so by adsorptive endocytosis. We will further determine spinal cord uptake of 125I-LIF and 1251-EGF in various regions and time course after injury, compare the results with those of permeability markers (radioactively labeled albumin and inulin as indicators of barrier disruption), and test the effects of receptor antibodies and endocytosis inhibitors on the increased radiotracer uptake after SCI. We expect that SCI upregulates receptor-related transport (for LIF) without affecting adsorptive transcytosis (for EGF), and that enhanced LIF transport correlates with increased endothelial LIFRalpha receptor expression. To test the hypothesis that LIF benefits spinal cord regeneration after crossing the BSCB, we will determine histological and electrophysiological evidence of axonal regeneration. We expect that tract tracing, neurofilament staining, and intraspinal conduction of evoked potentials will be increased by LIF treatment after peripheral delivery when its transport is upregulated. These changes will coincide with improved behavioral performance. To test the hypothesis that methylprednisolone potentiates the therapeutic effects of LIF and upregulates LIF transport, we will examine not only these regeneration parameters but also transport efficacy after methylprednisolone or combined treatment. By completing these studies, we will have demonstrated that transport of neurotrophic cytokines after SCI can be modulated to facilitate functional restoration. Therefore, the BBB/BSCB is not a simple barrier but also a gate for spinal cord regeneration. Understanding the mechanisms of cytokine transport at this regulatory interface would help in the design of new approaches to treat SCI.

足够的神经营养支持对于脊髓再生至关重要。然而，在脊髓损伤部位（SCI）部位的神经营养蛋白和神经营养细胞因子的产生不足。血脑/血脊髓屏障（BBB/BSCB）介导了周围的选择性神经营养性细胞因子的渗透。我们建议在SCI后，在BSCB处的白血病抑制因子（LIF）的运输系统上调，并增强了LIF益处的运输功能恢复。为了测试LIF通过受体相关的运输跨越BSCB的假设，并且SCI后运输系统上调，我们将测量12SI-LIF的血液到脊髓转移，测试不同类别的运输抑制剂的影响，并比较 表皮生长因子的结果（125-EGF）。我们预计，LIF受体抗体将减少12SI-LIF的进入，而多阳离子肽和Dansylcadaverin将减少12SI-EGF的进入，而不会通过EGF受体抗体降低。这将支持LIF通过受体介导的运输跨越BSCB的概念，而EGF则通过吸附性内吞作用。我们将进一步确定在各个区域和受伤后的125i-LIF和1251-EGF的脊髓吸收，并将结果与​​渗透性的结果进行比较 标记物（放射性标记的白蛋白和诱导蛋白是屏障破坏的指标），并测试受体抗体和内吞作用抑制剂对SCI后放射性示意剂摄取增加的影响。我们预计SCI会上调与受体相关的转运（对于LIF）而不会影响吸附性转介异生命（对于EGF），并且增强的LIF转运与内皮Lifralpha受体表达的增加相关。为了测试跨越BSCB后的LIF有益于脊髓再生的假设，我们将确定轴突再生的组织学和电生理学证据。我们期望这道追踪，神经丝染色和 外周递送运输后，诱发电位的载体内传导将通过LIF处理增加。这些变化将与改善行为绩效相吻合。为了检验甲基强酮可以增强LIF和上调LIF转运的治疗作用的假设，我们将不仅检查这些再生参数，而且还要检查甲基促进性甲硅酮或联合治疗后的转运功效。通过完成这些研究，我们将证明，可以调节SCI后神经营养性细胞因子的运输以促进功能恢复。因此，BBB/BSCB不是简单的障碍，而是脊髓再生的门。了解该调节界面上细胞因子转运的机制将有助于设计新方法治疗SCI。