Role of Eph Receptors after Spinal Cord Injury

Eph 受体在脊髓损伤后的作用

• 批准号: 6766633
• 负责人: JORGE David MIRANDA
• 金额: $ 13.66万
• 依托单位: UNIVERSITY OF PUERTO RICO MED SCIENCES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6766633
• 关键词: axon; biological signal transduction; blood brain barrier; enzyme activity; gene expression; immunocytochemistry; in situ hybridization; laboratory mouse; laboratory rabbit; molecular cloning; nervous system regeneration; neurogenesis; neuronal guidance; polymerase chain reaction; protein structure function; protein tyrosine kinase; spinal cord injury; synaptogenesis; western blottings

Spinal cord injury (SCI) generates a cascade of events that lead to inhibition of axonal regeneration. These molecular and biochemical changes represents the presence of repulsive factors that may restrict or block neurite outgrowth after CNS trauma. Members of the Eph subfamily of receptor tyrosine kinases (RTKs)have been associated with axonal pathfinding, target recognition and synapse formati on during development. It has been shown that these roles are accomplished by repulsive interactions caused after ligands binding. However, the role of EphAs in inhibiting axonal outgrowth in adult injured spinal cord is unknown. The expression of some of these receptors after injury was examined with standardized semi-quantitative RT-PCRanalysis. Results showed that several EphA's RTKs were induced after the injury and this enhanced expression persisted for several days. The expression of the EphA's after SCI were localized by immunocytochemistry and the results indicated that at the lesion epicenter, the immunoreactivity was focused in the lateral and ventral region of the white matter. These results suggest that these EphA's may be involved in the establishment of the non-permissive environment for axonal regeneration after CNS trauma. It is the objective of this proposal to block EphA's gene expression with antisense technology, reducing the nonpermissive environment generated after contusion to the spinal cord. Behavioral (BBB, grid walking, narrow-beam crossing, righting reflex and climbing test), physiological (transcranial magnetic motor evoked potentials) and anatomical tracing studies will be performed to monitor axonal regeneration and functional recovery after blockade of these repulsive proteins in SCI. In addition, neurotrophic factors will be used together with the antisense oligonucleotides to enhance the axonal outgrowth across the injury site. Establishing the EphA recept or roles, both on the regenerating fibers and in the local microenvironment, may lead to novel therapeutic strategies to enhance regeneration and functional recovery after SCI.

脊髓损伤 (SCI) 会产生一系列事件，导致轴突抑制 再生。这些分子和生化变化代表了排斥性的存在 可能限制或阻止中枢神经系统创伤后神经突生长的因素。以弗所成员 受体酪氨酸激酶 (RTK) 亚家族与轴突寻路相关， 发育过程中的目标识别和突触形成。事实证明，这些 作用是通过配体结合后引起的排斥相互作用来实现的。然而，角色 EphAs 抑制成人损伤脊髓轴突生长的作用尚不清楚。通过标准化半定量 RT-PCR 分析检查了损伤后其中一些受体的表达。结果显示，损伤后诱导了多个EphA的RTK，并且这种增强的表达持续了数天。通过免疫细胞化学对 SCI 后 EphA 的表达进行定位，结果表明，在病变中心，免疫反应性集中在白质的外侧和腹侧区域。这些结果表明这些EphA可能参与中枢神经系统创伤后轴突再生的非许可环境的建立。本提案的目的是通过反义技术阻断EphA的基因表达，减少脊髓挫伤后产生的不良环境。将进行行为（BBB、网格行走、窄束交叉、翻正反射和攀爬测试）、生理（经颅磁运动诱发电位）和解剖追踪研究，以监测 SCI 中这些排斥蛋白被阻断后的轴突再生和功能恢复。此外，神经营养因子将与反义寡核苷酸一起使用，以增强跨损伤部位的轴突生长。在再生纤维和局部微环境中建立 EphA 受体或作用，可能会产生新的治疗策略，以增强 SCI 后的再生和功能恢复。