Mechanisms of SCI Recovery after hCNS Stem Cell Grafts

描述（由申请人提供）：许多事件导致SCI后的最终结果，包括神经元、少突胶质细胞和轴突损失、脱髓鞘、神经胶质瘢痕形成和抑制性分子沉积以及内源性再生能力。这些事件定义了研究影响功能恢复的干预措施的作用机制的关键点。基于细胞的治疗策略的发展，包括培养的雪旺细胞和嗅鞘细胞，胎儿脊髓组织和胚胎干细胞（ES）衍生的祖细胞，是目前SCI的强烈兴趣。特别是，CNS干细胞（CNS-SC）具有迁移和分化为神经元，少突胶质细胞和星形胶质细胞的能力，移植后可以以多种方式使受损的脊髓受益。这些包括新神经元和少突胶质细胞的分化和功能性植入，改变宿主细胞的再生或髓鞘再生潜力，以及减少宿主胶质瘢痕形成或抑制性基质分子（例如蛋白聚糖）的沉积。我们已经发现，CNS-SC银行的细胞开始从前瞻性分离的人胎脑，使用单克隆抗体的荧光激活细胞分选（FACS）的生存和移植在挫伤的免疫缺陷NOD-scid小鼠。在SCI后9天移植人CNSSC神经球的挫伤小鼠显示出改善的旷场运动功能恢复。这些高度富集的人CNS-SC可以重复分离，能够在培养物中作为神经球长期生长，并且我们的初步数据表明它们保持其在损伤的脊髓中分化为神经元和少突胶质细胞的能力。本提案的目的是通过实验测试观察到的功能恢复的基础，测试人CNS-SC分化和功能性移植或改变如上所述的宿主对损伤的反应的假设。此外，我们还将测试这一假设，即运动将协同细胞移植，以改善运动恢复，基于其已知的作用，促进神经发生和我们的数据表明增强运动结果在挫伤小鼠在自愿轮运行范例。

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.