ADHESION MOLECULES EFFECTS ON BRAIN WOUND REPAIR

粘附分子对脑损伤修复的影响

• 批准号: 2272763
• 负责人: George M Smith
• 金额: $ 9.06万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2272763
• 关键词: astrocytes; brain; cadherins; chondroitin sulfates; cytokine; enzyme linked immunosorbent assay; extracellular matrix proteins; gene expression; genetic manipulation; genetic regulation; growth factor; growth inhibitors; immunocytochemistry; immunosuppressive; laboratory rat; laminin; nervous system regeneration; nervous system transplantation; neural cell adhesion molecules; northern blottings; scars; tenascin; tissue /cell culture; western blottings; wound healing

After injury, the immature central nervous system (CNS) has a greater propensity to promote wound repair and regeneration than the mature CNS. This difference is most likely due to the reduced growth-supportive environment of the adult CNS. For example, our previous studies show that CNS wound healing decreased after injury to older rodents. This decrease is paralleled by a decrease in the expression of NCAM, N-cadherin, and laminin, in which only laminin is reexpressed after injury to adults. Injury to the adult CNS but not the immature CNS also results in the increased expression of the growth-inhibitory molecules tenascin and chondroitin sulfate proteoglycan (CS-PG). Our preliminary results show that activated macrophages release cytokines and growth factors that stimulate astrocytcs to increase their expression of these molecules and that immunosuppressive drug treatments reduce the presence of these molecules after brain injury. This proposal is designed to test the hypothesis that wound healing and axonal regeneration within the CNS can be improved by controlling the regulatory mechanisms that induce the expression of growth-inhibitory molecules and by reintroducing specific adhesion molecules back into the wound cavity. To determine the factors that regulate the expression of laminin, tenascin, and CS-PG, astrocytes both in vitro (Specific Aim I) and in vivo (Specific Aim II) will be treated with cytokines and growth factors. Several immunosuppressive drugs will be tested to examine their effect in reducing the expression of the growth-inhibitory molecules (Specific Aim II) and promoting wound closure and axonal regeneration (Specific Aim III). Finally, immunosuppressive drug treatment will be coupled with the transplantation of astrocytes genetically engineered to express high amounts of NCAM, N-cadherin, or both to examine their combined effect on promoting wound closure and axonal regeneration (Specific Aim IV). Relative changes in the expression of these molecules will be quantified using Northern, immunoblot, and ELISA analyses. Immunohistochemistry will also be used to identify the location and number of astrocytes expressing these molecules and to examine the extent of glial scar formation and axonal regeneration. The importance of this work is threefold: (1) it will identify the injury- induced factors that regulate astrocyte production of growth-inhibitory molecules; (2) it will determine if reductions in the production of growth-inhibitory molecules improve wound healing and axonal regeneration; and (3) it will examine the interactions between the growth-supportive and growth-inhibitory molecules and how they effect CNS wound healing and axonal regeneration. The experiments outlined in this proposal will define the role of adhesion and extracellular matrix molecules in mediating astrocyte responsiveness in wound repair, thus forming the basis for future experiments related to the long term goal of reestablishing structural and functional continuity across lesions in the CNS.

受伤后，未成熟的中枢神经系统（CNS）具有更大的 比成熟的中枢神经系统促进伤口修复和再生的倾向。 这种差异很可能是由于减少了增长支持 成人中枢神经系统的环境。例如，我们以前的研究表明 啮齿动物受伤后，中枢神经系统伤口愈合减少。这种减少 与NCAM，N-钙粘蛋白和 层粘连蛋白，其中仅在成年人受伤后重新表达层粘连蛋白。 对成年中枢神经系统的伤害，但未成熟的中枢神经系统也导致 增加抑制生长抑制性分子的表达 硫酸软管蛋白聚糖（CS-PG）。我们的初步结果显示 激活巨噬细胞释放细胞因子和生长因子 刺激星形胶质细胞以增加它们对这些分子的表达，并 免疫抑制药物治疗减少了这些 脑损伤后分子。该建议旨在测试 假设中枢神经系统内的伤口愈合和轴突再生可以 通过控制诱导的调节机制来改善 表达抑制生长分子并通过重新引入特异性 粘附分子回到伤口腔中。确定因素 调节层粘连蛋白，替抗激素和CS-PG的表达，星形胶质细胞 体外（特定目标I）和体内（特定目标II）都将是 用细胞因子和生长因子治疗。几种免疫抑制药物 将进行测试以检查它们在降低表达的影响 生长抑制分子（特定AIM II）并促进伤口闭合 和轴突再生（特定目标III）。最后，免疫抑制 药物治疗将与星形胶质细胞的移植相结合 经过基因工程，以表达大量的NCAM，N-钙粘蛋白或 两者都检查它们对促进伤口闭合的综合作用，并且 轴突再生（特定目标IV）。表达的相对变化 这些分子将使用北部，免疫印迹和 ELISA分析。免疫组织化学也将用于识别 表达这些分子的星形胶质细胞的位置和数量 检查神经胶质疤痕形成和轴突再生的程度。这 这项工作的重要性是三倍：（1）它将确定伤害 - 调节星形胶质细胞生长抑制性星形胶质细胞的诱导因子 分子； （2）它将确定生产的减少是否减少 抑制生长的分子改善伤口愈合和轴突再生； （3）它将检查增长支持和 生长抑制分子及其如何影响中枢神经系统伤口愈合和 轴突再生。该提案中概述的实验将定义 粘附和细胞外基质分子在介导中的作用 伤口修复中的星形胶质细胞反应性，从而构成了 与重建的长期目标有关的未来实验 中枢神经系统病变之间的结构和功能连续性。