Combination therapy with glial restricted progenitors and miRNAs to repair stroke damage

项目摘要 干细胞用于治疗目的的前景是最有希望的 近年来，科学和医学。这方面的进展很大，包括 更好地理解干细胞生物学，识别干细胞的新来源， 对多种疾病的治疗效果令人鼓舞。中风仍然是最大的挑战之一， 在医学上，很少或没有有效的治疗方法。干细胞临床前研究 令人鼓舞，并导致了一些临床试验的启动。不幸的是，这些试验 显示了令人满意的治疗结果。有许多人认为这一失败的原因， 主要原因之一是干细胞的生物分布效率低下， 中风后的微环境动脉内输送可能会绕过这一限制， 已经尝试使用这种方法直接靶向脑损伤。在以前的研究中， 我们利用VLA-4/VCAM-1通路，证明了神经胶质限制性祖细胞工程化， 过表达VLA-4可以在动脉内注射后有效地靶向中风病变。我们应用 非侵入性纵向MRI和多光子显微镜，并证明，除了有效的 在脑内皮的表面对接，它们也经历向脑实质的渗出。 这是令人兴奋的，但我们遇到了挑战。在到达中风的恶劣环境后 在薄壁组织中，GRP不增殖并且不有效地髓鞘化。为了应对这一挑战，我们 提出了一种策略，以支持功能的GRP通过共注射与miRNA负载的脂质体。具体 将GRP和miRNA靶向中风损伤将通过我们建立的VLA来实现， 4/VCAM-1平台。为了优化两种治疗剂的递送，我们建议监测 新的分子磁共振成像靶向方法-化学交换 饱和转移（CEST）。这种成像方法能够选择性地检测个体CEST。 允许多色成像的造影剂。这种特性使得独立成像成为可能 注射治疗性细胞以及携带miRNA的脂质体并优化移植 最有效地传递这两种元素的参数。我们将进行体外筛选， 支持GRP功能的miRNA，主要关注其增殖和分化 向髓鞘少突胶质细胞转化一旦建立了图像引导的共注射方案， 最好的候选miRNA被鉴定，我们将继续测试MCAO小鼠的治疗效果 模型

Project Summary The prospect of using stem cells for therapeutic purposes has been one of the most promising fields of science and medicine in recent years. Progress in this area has been substantial, including a better understanding of stem cell biology, the identification of new sources of stem cells, and encouraging therapeutic results in a variety of diseases. Stroke remains one of the greatest challenges in medicine, with little or no effective treatments available. Preclinical studies using stem cells have been encouraging and have led to the initiation of a few clinical trials. Unfortunately, none of these trials demonstrated a satisfactory therapeutic outcome. There are many suggested reasons for that failure, with one of the primary reasons being an inefficient biodistribution of stem cells and hostile unsupportive microenvironment after stroke. Intraarterial delivery could potentially bypass this limitation, and a few attempts have been made to use this approach for direct targeting of brain lesions. In previous studies, we exploited VLA-4/VCAM-1 pathway and demonstrated that glial restricted progenitors engineered to overexpress VLA-4 can be efficiently targeted to stroke lesion after intraarterial injection. We applied non-invasive longitudinal MRI and multiphoton microscopy and demonstrated that in addition to efficient docking at the surface of cerebral endothelium they also undergo diapedesis into brain parenchyma. This is exciting but we encountered a challenge. After arriving in the hostile environment of stroke parenchyma, GRPs do not proliferate and do not myelinate efficiently. To address this challenge, we propose a strategy to support function of GRPs by co-injection with miRNAs-loaded liposomes. Specific targeting of both GRPs and miRNAs to stroke injury will be accomplished by our established VLA- 4/VCAM-1 platform. To optimize delivery of both therapeutic agents we propose to monitor the procedure of targeting with novel molecular magnetic resonance imaging - chemical exchange saturation transfer (CEST). This imaging method enables selective detection of individual CEST- contrast agent allowing multi-color imaging. This quality makes it possible to independently image injection of the therapeutic cells as well as miRNA-carrying liposomes and optimize the transplantation parameters for the most efficient delivery of both elements. We will perform in vitro screening for miRNAs that support function of GRPs with the main focus being their proliferation and differentiation towards myelinating oligodendrocytes. Once the image-guided co- injection protocol is established and best miRNA candidates are identified, we will proceed to testing therapeutic efficacy in MCAO mouse model.