Mechanisms of secondary injury after SCI

描述(申请人提供)：先天免疫反应显然是中枢神经系统创伤中继发性损伤级联反应的组成部分，但神经胶质和单核细胞衍生的促炎细胞因子的作用因多个浓度依赖受体介导的多个下游效应以及快速变化和演变的微环境而变得复杂。我们的新发现有力地支持了这一假设，即肿瘤坏死因子和AMPAR的变化在中枢神经系统损伤后的继发性损伤和恢复中都是关键的。使用可溶性肿瘤坏死因子受体蛋白(STNFR1)隔离肿瘤坏死因子可减少颈椎脊髓损伤后的损伤，并以高度剂量依赖的方式改善神经预后。我们建议扩大我们对肿瘤坏死因子和AMPAR转运的研究，将其作为脊髓损伤的治疗靶点，使用多元方法来测试临床前的疗效。依那西普(Etan)是一种临床用于类风湿关节炎的肿瘤坏死因子隔离蛋白；托吡酯(TPM)是一种具有AMPAR拮抗作用的神经保护、抗癫痫药物。我们将单独和联合使用这些药物来打击AMPAR贩运和AMPAR活动。我们将系统地评估这些药物的生物学反应，使用在我们之前的工作中预测神经结果的早期损伤后生物标记物。我们将使用生物标记物数据来计划临床前剂量和时间方案，以评估对颈部和胸部大鼠脊髓损伤的有效性，并评估它们对自主神经、感觉和运动结果的影响。这些努力旨在推动抗肿瘤坏死因子治疗脊髓损伤的临床应用，并可能适用于其他中枢神经系统退行性疾病。我们提出了三个具体的目标：目的1：评价Etan和TPM对颈脊髓损伤后AMPAR表面表达、细胞死亡和促炎细胞因子产生的时程和程度的影响。我们预测，这些治疗将减少细胞死亡的前馈级联。目的2.在这些数据的指导下，我们将通过各种前肢功能测试(美容、爪子放置、T台走秀和IBB)来优化单项和联合治疗的剂量和时机，以最大限度地促进单侧颈椎SCI后6周的恢复。目的3：我们将通过包括自主神经、感觉和运动结果的一系列测试来测试优化的药物方案对胸部挫伤损伤恢复的影响。这将确定疗效是否延伸到多种脊髓损伤模型。肿瘤坏死因子和AMPAR也参与了神经损伤后慢性超敏反应的产生(Choi等人，2010)，我们将测试这种情况是否也发生在脊髓损伤后。TPM已经被用于治疗慢性脊髓损伤疼痛。我们预测，使用Etan和TPM的急性治疗能够产生更好的运动结果，也将导致长期异位痛觉和紧张性、厌恶性中枢性疼痛的减少(King等人，2009年)，后者通过位置偏好测试来衡量。

DESCRIPTION (provided by applicant): The innate immune response is clearly an integral part of the secondary injury cascade in CNS trauma, but the role of glial and monocyte derived pro-inflammatory cytokines is complicated by multiple downstream effects mediated by multiple concentration-dependent receptors, and a rapidly changing and evolving microenvironment. We have new findings that strongly support the hypothesis that TNF and AMPAR changes are critical in both secondary injury and recovery after CNS injury. Sequestering TNF using soluble TNF receptor protein (sTNFR1) reduces damage after cervical SCI, and, in a highly dose-dependent manner, improves neurological outcomes. We propose to extend our studies of TNF and AMPAR trafficking as a therapeutic target for SCI using a multivariate approach to test preclinical efficacy. Etanercept (ETAN) is a TNF-sequestering protein biologic used clinically in rheumatoid arthritis; topiramate (TPM) is a neuroprotective, anti-epileptic drug that has AMPAR antagonism. We will use these drugs to target AMPAR-trafficking and AMPAR activity, separately and in combination. We will systematically evaluate the biological responses to these drugs using early post-injury biomarkers that have predicted neurological outcomes in our prior work. We will use the biomarker data to plan preclinical dose and timing regimens to evaluate effectiveness in both cervical and thoracic rat SCI, and evaluate their effects on autonomic, sensory and motor outcomes. These efforts are aimed at moving towards clinical application of anti-TNF therapies for SCI, and may be applicable to other CNS degenerative disorders as well. We propose three specific aims: Aim 1: We will evaluate the effects of ETAN and TPM on the time course and extent of biomarkers of AMPAR surface expression, cell death and the production of pro-inflammatory cytokines after cervical SCI. We predict that these treatments will reduce the feed-forward cascade of cell death. Aim 2. Guided by these data, we will optimize dose and timing of single and combination therapies to maximize six week recovery after unilateral cervical SCI using a variety of forelimb functional tests (grooming, paw placement, Catwalk and IBB). Aim 3: We will test the effects of optimized drug regimens on recovery from thoracic contusion lesions using a battery of tests that includes autonomic, sensory, and motor outcomes. This will establish whether efficacy extends to multiple models of SCI. TNF and AMPARs are also involved in the production of chronic hypersensitivity after nerve injury (Choi et al, 2010), and we will test whether this occurs after SCI as well. TPM is already used to treat chronic SCI pain. We predict that acute treatments with ETAN and TPM that result in better motor outcomes will also result in reductions in long term allodynia and in tonic, aversive central pain (King et al, 2009), the latter measured by place preference tests.