Disseminated gene delivery to the CNS by human iPSC-derived neural stem cells

 描述（由申请人提供）：神经干细胞（NSC）在某些情况下在脑内迁移的天然能力长期以来使其成为治疗CNS疾病的候选者。将人类体细胞重编程为组织特异性干细胞的方法的发展为使用NSC治疗许多脑疾病提供了巨大的希望。在人类疾病的小鼠模型中的NSC移植实验已经证明了在几种类型的疾病中至少一些病理学的校正，为基于NSC的方法提供了原理证明。然而，有效翻译的一个重要障碍是移植水平低。由于缺陷的性质，神经遗传性疾病在CNS中具有全局分布的病变，因此治疗需要供体细胞的弥散分布。然而，要实现这一目标，需要更好地了解神经干细胞移植后的特性。我们已经将人类患者成纤维细胞重编程为多能干细胞（iPSC），从它们衍生NSC，并遗传校正hu-iPS-NSC。我们提出异种移植研究来评估工程化hu-iPS-NSC对移植后分布和存活的影响。我们将测试在脑内递送可扩散蛋白质的治疗效果，在人溶酶体贮积病（LSD）的良好表征的小鼠模型中。有超过50种LSD，它们是影响CNS的所有遗传性儿童遗传疾病的大部分原因。原则上，基于溶酶体酶从遗传校正的细胞输出并被突变细胞吸收以恢复缺失的酶活性的观察，可以对大多数LSD使用常见的治疗策略。初步研究表明，hu-iPS-NSC以低水平植入NOD-SCID小鼠脑中。拟议的实验将调查移植后分散和供体细胞的存活的基本特征，以解决NSC植入不足的问题。我们已经获得了令人信服的初步数据，证明了拟议实验的可行性，我们将使用定量分析来测量植入量，分化为成熟神经细胞类型和病理变化。这项研究的长期战略是在小鼠大脑中开发NSC移植物，使其能够在未来的转化研究中在大脑疾病的大型动物模型中进行测试，并最终进入比小鼠大脑大3,000倍的人脑。很明显，在这个问题上的进展需要在理解NSC植入的生物学和发展策略以提高植入方面取得重大进展。

 DESCRIPTION (provided by applicant): The natural ability of neural stem cells (NSCs) to migrate within the brain, under certain circumstances, has long made them a candidate for treatment of CNS diseases. The development of methods to reprogram human somatic cells into tissue specific stem cells has provided great hope for using NSC therapies for many brain disorders. NSC transplantation experiments in mouse models of human diseases have demonstrated correction of at least some pathology in several types of diseases, providing proof-of-principle for the NSC- based approach. However, a significant barrier to effective translation is the low level of engraftment that occurs. Neurogenetic diseases have globally distributed lesions in the CNS due to the nature of the defect, thus treatment requires disseminated distribution of the donor cells. Achieving that will, however, require much better understanding of the post-transplantation properties of NSCs. We have reprogrammed human patient fibroblasts into pluripotent stem cells (iPSCs), derived NSCs from them, and genetically corrected the hu-iPS- NSCs. We propose xenograft studies to evaluate the effects of engineering hu-iPS-NSCs on post-transplant distribution and survival. We will test the therapeutic effectiveness of delivering a diffusible protein within the brain, in a well-characterized mouse model of a human lysosomal storage disease (LSD). There are >50 individual LSDs and they are responsible for a large portion of all inherited childhood genetic diseases that affect the CNS. A common treatment strategy can be used, in principle, for most of the LSD's, based on the observation that lysosomal enzymes are exported from genetically corrected cells and taken up by mutant cells to restore the missing enzymatic activity. Preliminary studies indicate the hu-iPS-NSCs engraft in the NOD- SCID mouse brain at low levels. The proposed experiments will investigate basic features of post-transplant dispersion and survival of the donor cells to address the problem of inadequate NSC engraftment. We have obtained compelling preliminary data demonstrating the feasibility of the proposed experiments and we will use quantitative analyses to measure amounts of engraftment, differentiation into mature neural cell types, and changes in pathology. The long-term strategy of this line of research is to develop NSC transplants in the mouse brain to a level where they can be tested in large animal models of brain diseases in future translational studies and eventually into the human brain which is ~3,000 times larger than the mouse brain. It is clear that progress on this problem needs significant advances in understanding the biology of NSC engraftment and development of strategies to enhance engraftment.