Oligodendrocyte Genesis after Spinal Cord Injury

前少突胶质细胞（OL）死亡发生在脊髓损伤（SCI）后。因为这些细胞有髓鞘 轴突，它们的损失导致轴突功能障碍，并有助于SCI后的功能丧失。尽管许多研究 尽管已经描述了SCI后OL死亡的特征，但很少有人研究是否发生了内源性OL替代。我们 最近注意到在病变腔周围的组织边缘产生大量新的OL SCI之后在目前的提案中，这些令人兴奋的发现将通过确定这些新的OL 有助于轴突髓鞘再生，并检查其形成所涉及的机制。我们特别 将测试这一假设，即创伤性损伤的成人脊髓中的OL发生导致 脊髓轴突的髓鞘再生，并依赖于星形胶质细胞衍生的CNTF。在目标1中，我们将扩大 通过表征SCI后OL髓鞘再生的时空范围，初步数据。因为只有 新产生的OL可以使轴突再生，这些数据将提供关于新细胞在多大程度上 有助于内源性修复。为了补充这些数据，我们将使用GFP-逆转录病毒谱系追踪， 检查损伤后分裂细胞的命运，并荧光标记新衍生的OL和髓鞘 成鞘轴突这些研究将在目标2中通过检查新的OL 脊髓损伤后的再生和髓鞘再生依赖于CNTF的存在。慢病毒-siRNA技术将是 用于沉默CNTF表达，并检查脊髓中少突胶质细胞祖细胞的变化。 增殖、新OL形成和髓鞘形成。根据我们的试点数据，我们预测OL的数量 沿着病变边界的髓鞘再生将显著减少，从而导致脊髓损伤的髓鞘再生减少。 轴突我们还将研究CNTF的缺失和 少生在目标3中，我们将研究CNTF介导效应的作用机制，包括 评估CNTF受体和细胞内信号分子的细胞表达。由于CNTF已知 刺激FGF-2的产生，我们和其他人表明SCI后FGF-2上调，我们还将 评估CNTF是否是SCI后FGF-2表达所必需的。总的来说，生成的数据将 提供了新的信息，调节新的OL形成在受伤的成年中枢神经系统和能力，这些 细胞，以帮助修复创伤性SCI引起的损伤。

Protracted oligodendrocyte (OL) death occurs after spinal cord injury (SCI). Because these cells myelinate axons, their loss leads to axon dysfunction and contributes to functional loss after SCI. Although many studies have characterized OL death after SCI, few have examined whether endogenous OL replacement occurs. We recently noted that a large number of new OLs are generated in the rim of tissue surrounding the lesion cavity after SCI. In the current proposal, these exciting findings will be followed up by determining if these new OLs contribute to axon remyelination and examining the mechanisms involved in their formation. Specifically, we will test the hypothesis that OL genesis in the traumatically injured adult spinal cord leads to remyelination of spinal axons and is dependent on astrocyte-derived CNTF. In Aim 1, we will expand upon preliminary data by characterizing the spatio-temporal extent of OL remyelination after SCI. Because only newly generated OLs can remyelinate axons, this data will provide information on the extent that the new cells contribute to endogenous repair. To complement this data, we will use GFP-retroviral lineage tracing to examine the fate of dividing cells after injury and to fluorescently label newly derived OLs and myelin ensheathing axons. These studies will be followed up in Aim 2 by examining the extent to which new OL genesis and OL remyelination depend on the presence of CNTF after SCI. Lentiviral-siRNA technology will be used to silence CNTF expression and spinal cords will be examined for changes in oligodendrocyte progenitor proliferation, new OL formation and myelination. Based on our pilot data, we predict that the number of OLs along lesion borders will be significantly reduced thereby leading to a decrease in remyelination of spinal axons. We will also examine the functional consequences of the absence of CNTF and reduction on oligogenesis. In Aim 3, we will examine the mechanisms of action for CNTF-mediated effects, including evaluating cellular expression of CNTF receptors and intracellular signaling molecules. Since CNTF is known to stimulate FGF-2 production and we and others show that FGF-2 is upregulated after SCI, we will also evaluate whether CNTF is essential for post-SCI FGF-2 expression. Collectively, the data generated will provide novel information on regulation of new OL formation in the injured adult CNS and the ability of these cells to help repair the damage induced by traumatic SCI.