Promoting axonal growth and tissue repair in stem cell therapy after stroke

描述（申请人提供）：干细胞移植为脑缺血和其他中枢神经系统疾病提供了一种有希望的有效治疗方法。移植细胞通过不同的机制显示出治疗益处，包括增强营养支持和补充丢失的细胞和大脑结构。胚胎干细胞（ES）被认为是基于细胞治疗的几种有用的候选细胞类型，由于其在体外和移植到缺血性脑后都能发育成神经元和非神经元细胞的能力，胚胎干细胞（ES）已经受到了广泛的关注。阻碍细胞治疗效率和疗效的两个主要障碍是移植细胞的存活不足和轴突的生长。此外，或许更重要的是，移植细胞如何被引导形成正确的神经网络并产生功能恢复仍未得到解决。这个问题与临床极其相关，但到目前为止它在很大程度上被忽视了。利用独特的大鼠须桶皮层中风模型，本研究采用了新的策略，可以显著增强移植细胞的耐受性，显著促进移植神经祖细胞的靶向性轴突生长，促进缺血脑中宿主神经网络/通路的有组织整合。特异性目标1将在干细胞治疗中应用缺氧预处理（HP）的保护机制。小鼠胚胎干细胞衍生的神经祖细胞（ESNPCs）将进行HP预处理，然后测试其在中风后大脑中的存活率。特异性Aim 2将测试表达神经元特异性和可分泌的RhoA抑制剂C3转移酶的移植ESNPCs轴突生长的增强。我们将验证C3的局部表达/传递促进目标特异性（桶状皮质）轴突生长的假设。晶须刺激产生的传入输入信号将进一步加强定向再生。皮质内和丘脑皮质连接的形态学修复将被评估。特异性目标3将致力于针对须-丘脑-脑桶皮层通路的功能评估。光学成像、电生理记录和再生桶状皮质的局部葡萄糖代谢将为hp - esnpc移植在富集环境中实现功能恢复提供强有力的证据。这项研究将在基础研究和转化研究中取得一些令人兴奋的进展，并将其应用于缺血性卒中的联合治疗。我们的长期目标是开发有效、安全、可行的策略，推动干细胞治疗进入临床应用。

DESCRIPTION (provided by applicant): Stem cell transplantation offers a promising efficacious therapy for cerebral ischemia and other CNS disorders. Transplanted cells show therapeutic benefits via different mechanisms, including enhanced trophic support and the replenishment of lost cells and brain structures. Of the several cell- types considered useful candidates for cell-based therapeutics, embryonic stem (ES) cells have received a great deal of attention due to their ability to develop into neurons and non-neuronal cells both in vitro and after transplantation into the ischemic brain. Two major hurdles that have hindered the efficiency and efficacy of cell-based therapy are the insufficient survival and axonal outgrowth of transplanted cells. Moreover, and perhaps more importantly, how the transplanted cells can be directed to form correct neural networks and produce functional recovery is still unresolved. This issue is extremely clinically relevant, yet so far it has been largely ignored. Using the unique whisker-barrel cortex stroke model in rats, the present investigation incorporates novel strategies that will markedly enhance the tolerance of transplanted cells and significantly facilitate target-specific axonal growth of transplanted neural progenitors, promoting organized integration within host neural network/pathways in the ischemic brain. Specific Aim 1 will apply the well-characterized protective mechanism of hypoxic preconditioning (HP) in stem cell therapy. Mouse embryonic stem cell-derived neural progenitor cells (ESNPCs) will be HP pretreated and then tested for enhanced survival in the post-stroke brain. Specific Aim 2 will test the enhancement of axonal growth of transplanted ESNPCs that express the neuron-specific and secretable RhoA inhibitor C3 transferase. We will test the hypothesis that localized expression/delivery of C3 promotes target-specific (barrel cortex) axonal outgrowth. The directed regeneration will be further strengthened by afferent input signals generated by whisker stimulation. The morphological repair of intracortical and thalamocortical connections will be evaluated. Specific Aim 3 will be devoted to the functional assessments specific for the whisker-thalamus-barrel cortex pathway. Optical imaging, electrophysiological recordings and local glucose metabolism in the regenerated barrel cortex will provide compelling evidence for the functional recovery achieved by transplantation of HP-ESNPCs in the enriched environment. This investigation will apply some exciting progress in basic and translational research into a promising combination therapy for ischemic stroke. Our long term goal is to develop effective, safe, and feasible strategies to advance stem cell therapy into clinical applications.