Mechanisms of SCI Recovery after hCNS Stem Cell Grafts

描述(申请人提供)：一系列事件导致脊髓损伤后的最终结果，包括神经元、少突胶质细胞和轴突丢失，脱髓鞘，胶质瘢痕形成和抑制分子沉积，以及内源性再生能力。这些事件为研究影响功能恢复的干预措施的作用机制确定了临界点。以细胞为基础的治疗策略的发展，包括培养的雪旺细胞和嗅鞘细胞、胚胎脊髓组织和胚胎干细胞(ES)来源的前体细胞，是当前对脊髓损伤非常感兴趣的研究方向。尤其是中枢神经系统干细胞(CNS-SC)在移植后具有向神经元、少突胶质细胞和星形胶质细胞迁移和分化的能力，可通过多种方式惠及损伤脊髓。这些措施包括新神经元和少突胶质细胞的分化和功能植入，改变宿主细胞的再生或再髓鞘形成潜力，以及减少宿主胶质细胞的创伤或抑制基质分子(如蛋白多糖)的沉积。我们发现，使用基于单抗的荧光激活细胞分选(FACS)方法从预期分离的人胎脑中分离的CNS-SC库中的细胞在挫伤损伤的免疫缺陷NOD-SCID小鼠中存活并移植。脊髓损伤后9天移植人CNSSC神经球的挫伤小鼠表现出更好的开放领域运动功能的恢复。这些高度浓缩的人CNS-SC可以重复分离，能够作为神经球在培养中长期生长，我们的初步数据表明，它们保持了分化为损伤脊髓中的神经元和少突胶质细胞的能力。这项建议的目的是通过实验测试观察到的功能恢复的基础，测试人类CNS-SC分化和功能移植或改变宿主对上述损伤的反应的假设。此外，我们还将测试这一假设，即运动将与细胞移植协同作用，以改善运动恢复，基于其在促进神经发生方面的已知作用，以及我们的数据显示，在自愿车轮跑步范式中，挫伤小鼠的运动结果得到增强。

DESCRIPTION (provided by applicant): A multitude of events contribute to the ultimate outcome following SCI, including neuron, oligodendrocyte and axonal loss, demyelination, glial scar formation and inhibitory molecule deposition, and endogenous capacity for regeneration. These events define critical points for investigation of the mechanism of action of interventions that affect functional recovery. The development of cell-based therapeutic strategies, including cultured Schwann and olfactory ensheathing cells, fetal spinal cord tissues, and embryonic stem cell (ES)-derived progenitors, is of strong current interest for SCI. In particular, CNS Stem Cells (CNS-SC), which have the ability to migrate and differentiate into neurons, oligodendrocytes and astrocytes upon transplantation could benefit the injured spinal cord in a variety of ways. These include differentiation and functional engraftment of new neurons and oligodendrocytes, modifying the regenerative or remyelination potential of host cells, and decreasing host glial scaring or deposition of inhibitory matrix molecules (e.g. proteoglycans). We have found that cells from CNS-SC banks initiated from prospectively isolated human fetal brain using monoclonal antibody based fluorescence activated cell sorting (FACS) survive and engraft in contusion-injured immunodeficient NOD-scid mice. Contusion-injured mice transplanted with human CNSSC neurospheres 9 days post-SCI show improved recovery of open field locomotor function. These highly enriched human CNS-SC can be reproducibly isolated, are capable of long term growth in culture as neurospheres, and our preliminary data suggest that they maintain their capacity to differentiate into neurons and oligodendrocytes in the injured spinal cord. The objective of this proposal is to experimentally test the basis for the observed functional recovery, testing the hypothesis that human CNS-SC either differentiate and functionally engraft or modify the host response to injury as described above. Further, we will also test the hypothesis that exercise will act synergistically with cell transplantation to improve locomotor recovery, based on its known role in promoting neurogenesis and our data demonstrating enhancement of locomotor outcome in contusion-injured mice in a voluntary wheel running paradigm.