Oligodendrocyte Genesis after Spinal Cord Injury

脊髓损伤(SCI)后会出现少突胶质细胞(OL)的迁延性死亡。因为这些细胞有髓鞘形成 轴突的丢失导致轴突功能障碍，导致脊髓损伤后功能丧失。尽管许多研究 关于脊髓损伤后OL死亡的特征，很少有人研究是否发生内源性OL替代。我们 最近注意到，在病变腔周围的组织边缘产生了大量新的OL 在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是否 有助于轴突的再髓鞘形成，并研究其形成的机制。具体来说，我们 将检验创伤损伤的成人脊髓中的OL起源导致 脊髓轴突的再髓鞘形成，并依赖于星形胶质细胞来源的CNTF。在目标1中，我们将扩展 根据初步数据，描述脊髓损伤后OL髓鞘再生的时空范围。因为只有 新产生的OL可以使轴突重新髓鞘形成，这些数据将提供有关新细胞程度的信息 有助于内源性修复。为了补充这一数据，我们将使用GFP-逆转录病毒谱系追踪来 观察损伤后分裂细胞的去向，并用荧光标记新衍生的OL和髓鞘 包裹着轴突。这些研究将在目标2中通过检查新的OL在多大程度上 脊髓损伤后CNTF的存在，决定了脊髓的发生和OL的再髓鞘形成。慢病毒-siRNA技术将是 用于沉默CNTF表达和脊髓将检查少突胶质细胞前体细胞的变化 增殖，新的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 沿病变边界将显著减少，从而导致脊柱髓鞘再生减少。 轴突。我们还将研究CNTF的缺失和减少对 寡头发生。在目标3中，我们将研究CNTF介导的效应的作用机制，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 为了刺激成纤维细胞生长因子-2的产生，我们和其他人发现脊髓损伤后成纤维细胞生长因子-2上调，我们还将 评估CNTF是否对脊髓损伤后成纤维细胞生长因子-2的表达起重要作用。总而言之，生成的数据将 为损伤的成人中枢神经系统中新的OL形成的调节及其能力提供新信息 帮助修复创伤性脊髓损伤的细胞。

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.