ES CELL TRANSPLANTATION AFTER SPINAL CORD INJURY

申请拨款支持一项新的研究计划项目，旨在探索胚胎干细胞移植在脊髓损伤后恢复功能的潜力。拟建项目团队的成员已经积累了研究小鼠胚胎干细胞沿神经谱系分化、减少神经系统细胞死亡的方法以及创伤性脊髓损伤啮齿动物模型的经验。在形成本提案特定背景的实验中，项目团队成员已经获得证据表明，小鼠es细胞衍生的神经谱系细胞（ESNLCs）可以成功移植到大鼠脊髓撞击损伤后9天形成的注射器/囊肿中。这些移植的ESNLCs存活了至少数周，部分填充腔腔并迁移到宿主组织中，并表达分化的少突胶质细胞、星形胶质细胞和神经元的标记物。所请求的计划项目资金将使项目团队成员能够以系统和假设驱动的方式构建这些早期实验。根据直接观察，大多数移植的ESNLCs在移植后的48小时内死亡，尤其是神经元在随后的几天内继续死亡，本文提出的实验重点将是通过旨在阻断细胞凋亡和兴奋毒性的药理学和基因工程方法来提高移植ESNLCs的存活率。预计今后几年的工作可能会以其他方式优化ESNLC移植程序。

Grant funds are requested to support a new research Program Project aimed at initiating an exploration of the potential of embryonic stem (ES) cell transplantation for restoring lost functions after spinal cord injury. Members of the proposed Project team have already developed experience working with mouse ES cells differentiated down neural lineages, methods for reducing cell death in the nervous system, and rodent models of traumatic spinal cord injury. In the experiments that form the specific background for the present proposal, Project team members have obtained evidence that mouse ES-cell derived neural lineage cells (ESNLCs) can be successfully transplanted into the syrinx/cyst that forms nine days after impact injury to the rat spinal cord . These transplanted ESNLCs survived for at least many weeks, partially filling the syrinx and migrating into host tissue, and expressed markers for differentiated oligodendrocytes, astrocytes, and neurons. The requested Program Project funding would enable Project team members to build on these early experiments in a systematic and hypothesis-driven fashion. Based on direct observations that a majority of transplanted ESNLCs die over the first 48 hours following transplantation and that neurons in particular continue to die over subsequent days, the emphasis of the experiments proposed here will be on improving the survival of transplanted ESNLCs through pharmacological and genetic engineering approaches aimed at blocking apoptosis and excitotoxicity. It is anticipated that work performed in subsequent years may be directed at optimizing the ESNLC transplantation procedure in other ways.