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

描述（由申请人提供）：干细胞移植为脑缺血和其他CNS疾病提供了一种有希望的有效治疗方法。移植的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。在被认为是基于细胞的治疗的有用候选物的几种细胞类型中，胚胎干（ES）细胞由于其在体外和移植到缺血性脑中后发育成神经元和非神经元细胞的能力而受到极大关注。阻碍基于细胞的治疗的效率和功效的两个主要障碍是移植细胞的存活和轴突生长不足。此外，也许更重要的是，如何引导移植的细胞形成正确的神经网络并产生功能恢复仍然没有解决。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。使用独特的须桶皮质中风模型大鼠，本研究采用了新的策略，将显着提高移植细胞的耐受性，并显着促进移植的神经祖细胞的靶向特异性轴突生长，促进有组织的整合宿主神经网络/途径在缺血性脑。具体目标1将在干细胞治疗中应用低氧预处理（HP）的良好特征保护机制。小鼠胚胎干细胞衍生的神经祖细胞（ESNPCs）将被HP预处理，然后测试其在中风后大脑中的存活率。具体目标2将测试表达神经元特异性和分泌型RhoA抑制剂C3转移酶的移植ESNPCs的轴突生长的增强。我们将测试C3的局部表达/递送促进靶特异性（桶皮质）轴突生长的假设。通过刺激触须产生的传入输入信号将进一步加强定向再生。将评价皮质内和丘脑皮质连接的形态修复。具体目标3将致力于特定于胡须-丘脑-桶皮质通路的功能评估。光学成像，电生理记录和局部葡萄糖代谢的再生桶皮层将提供令人信服的证据，在丰富的环境中移植HP-ESNPCs实现的功能恢复。这项研究将应用一些令人兴奋的进展，在基础和转化研究，以一个有前途的联合治疗缺血性中风。我们的长期目标是开发有效，安全和可行的策略，将干细胞治疗推向临床应用。

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.