Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, BSB-201, Charleston, SC, 29425, USA.
Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC, USA.
Neurochem Res. 2017 Oct;42(10):2777-2787. doi: 10.1007/s11064-017-2291-z. Epub 2017 May 15.
Spinal cord injury (SCI) is a complex debilitating condition leading to permanent life-long neurological deficits. The complexity of SCI suggests that a concerted multi-targeted therapeutic approach is warranted to optimally improve function. Damage to spinal cord is complicated by an increased detrimental response from secondary injury factors mediated by activated glial cells and infiltrating macrophages. While elevation of enolase especially neuron specific enolase (NSE) in glial and neuronal cells is believed to trigger inflammatory cascades in acute SCI, alteration of NSE and its subsequent effects in acute SCI remains unknown. This study measured NSE expression levels and key inflammatory mediators after acute SCI and investigated the role of ENOblock, a novel small molecule inhibitor of enolase, in a male Sprague-Dawley (SD) rat SCI model. Serum NSE levels as well as cytokines/chemokines and metabolic factors were evaluated in injured animals following treatment with vehicle alone or ENOblock using Discovery assay. Spinal cord samples were also analyzed for NSE and MMPs 2 and 9 as well as glial markers by Western blotting. The results indicated a significant decrease in serum inflammatory cytokines/chemokines and NSE, alterations of metabolic factors and expression of MMPs in spinal cord tissues after treatment with ENOblock (100 µg/kg, twice). These results support the hypothesis that activation of glial cells and inflammation status can be modulated by regulation of NSE expression and activity. Analysis of SCI tissue samples by immunohistochemistry confirmed that ENOblock decreased gliosis which may have occurred through reduction of elevated NSE in rats. Overall, elevation of NSE is deleterious as it promotes extracellular degradation and production of inflammatory cytokines/chemokines and metabolic factors which activates glia and damages neurons. Thus, reduction of NSE by ENOblock may have potential therapeutic implications in acute SCI.
脊髓损伤（SCI）是一种复杂的使人虚弱的疾病，导致永久性的终身神经功能缺陷。SCI 的复杂性表明，需要协同的多靶点治疗方法，以最佳地改善功能。脊髓损伤的复杂性增加了由激活的神经胶质细胞和浸润的巨噬细胞介导的继发性损伤因素的有害反应。虽然烯醇酶（尤其是神经元特异性烯醇酶（NSE））在神经胶质和神经元细胞中的升高被认为会引发急性 SCI 中的炎症级联反应，但 NSE 的改变及其在急性 SCI 中的后续影响仍然未知。本研究在雄性 Sprague-Dawley（SD）大鼠 SCI 模型中测量了急性 SCI 后 NSE 的表达水平和关键炎症介质，并研究了烯醇酶抑制剂 ENOblock 的作用。使用 Discovery 测定法，在单独用载体或 ENOblock 处理受伤动物后，评估血清 NSE 水平以及细胞因子/趋化因子和代谢因子。还通过 Western blot 分析脊髓样本中的 NSE 以及 MMPs 2 和 9 以及神经胶质标志物。结果表明，在用 ENOblock（100μg/kg，两次）处理后，血清中炎症细胞因子/趋化因子和 NSE、代谢因子的改变以及脊髓组织中 MMPs 的表达均显著降低。这些结果支持这样的假设，即通过调节 NSE 的表达和活性可以调节神经胶质细胞的激活和炎症状态。通过免疫组织化学分析 SCI 组织样本证实，ENOblock 减少了神经胶质增生，这可能是通过降低大鼠中升高的 NSE 而发生的。总的来说，NSE 的升高是有害的，因为它促进了细胞外降解以及炎症细胞因子/趋化因子和代谢因子的产生，从而激活了神经胶质细胞并损害了神经元。因此，ENOblock 通过降低 NSE 可能对急性 SCI 具有潜在的治疗意义。
