Regenerating CNS white matter using induced pluripotent stem cells

 描述(申请人提供)：使用诱导多能干细胞再生中枢神经系统白质-脑室周围白质软化症(PVL)是早产儿神经系统疾病的主要原因，导致脑瘫和认知问题。PVL的主要神经病理特征是局灶性和弥漫性脑室周围白质损伤，其特征是髓前少突胶质细胞(OLs)耗竭和髓鞘形成障碍。目前尚无治疗PVL的有效方法。近年来，发展新生儿脑损伤的细胞疗法得到了越来越多的支持。我们的实验室已将PVL研究确定为我们研究计划的战略重点领域。我们的长期目标是确定潜在的基于干细胞的PVL治疗策略。累积的研究表明，移植不同的干/祖细胞制剂对新生儿缺氧缺血性损伤具有治疗潜力。获得高纯度、均一的细胞是发育细胞的前提。 治疗。然而，目前在为移植研究和未来的临床应用获得同种干细胞/祖细胞方面存在一个共同的困难。此外，移植的最佳细胞类型仍不清楚。在人类组织和PVL动物模型中的研究表明，PVL损伤后并不缺乏少突胶质前体细胞(OPC)，因为它们的增殖增加，但其成熟在很大程度上被推迟。细胞死亡是 主要见于髓鞘前白斑，但不见于神经元。因此，神经前体细胞和OPC可能不是PVL损伤的最佳候选细胞。基于我们的初步数据，我们建议开发一种基于星形胶质细胞的新生儿脑损伤细胞疗法。我们最近的工作成功地从人类胚胎干细胞(HESCs)中成功地产生了高纯度和同质性(&gt；95%)的未成熟星形胶质细胞。我们进一步证明，移植hESC来源的星形胶质细胞在体外和体内都显示出强大的神经保护作用。星形胶质细胞在发育和损伤后再髓鞘形成过程中发挥着至关重要的作用。我们一直致力于从成纤维细胞中培养人诱导多能干细胞(HiPSCs)，并将其分化为OPC，用于髓鞘的再生和修复。与hESCs相比，hPSCs的一个主要优势是它们是同源细胞的无限来源，移植后可能不会发生免疫排斥反应。我们已经将我们高效的星形胶质细胞分化方案应用于HiPSC，并产生了HiPSC来源的未成熟星形胶质细胞。我们的初步观察表明，HiPSC来源的未成熟星形胶质细胞在体外可以促进OPC成熟为髓鞘少突胶质细胞。在这些先前和初步结果的基础上，我们建议在我们所建立的小鼠PVL模型中检测移植hPSC来源的星形胶质细胞是否促进新生脑损伤后的重新髓鞘形成，并探讨其潜在的机制。这项新颖的研究可能导致一种新的基于HiPSC来源的星形胶质细胞治疗PVL的方法，也将为了解OL和星形胶质细胞之间的相互作用提供新的见解，这是一个以前研究较少的领域。通过该项目获得的科学知识可能有助于基于干细胞的治疗策略的开发，用于治疗人类神经疾病，如PVL。

 DESCRIPTION (provided by applicant): Regenerating CNS white matter using induced pluripotent stem cells - Periventricular leukomalacia (PVL) is the leading cause of neurologic morbidity in premature infants leading to cerebral palsy and cognitive problems. The major neuropathologic hallmark of PVL is focal and diffuse periventricular white matter injury, featured by depletion of premyelinating oligodendrocytes (OLs) and myelination disturbances. No effective treatment for PVL is available. Recently, developing cell therapies for neonatal brain injury has gained increasing support. Our lab has identified PVL research as a strategic area of focus for our research program. Our long-term goal is to determine potential stem cell based therapeutic strategies for PVL. Accumulative studies indicate the therapeutic potential for neonatal hypoxic-ischemic injury with transplantation of different stem/progenitor cell preparations. It is prerequisite to derive cells in high purity and homogeneity for developing cell therapies. However, there is currently a common difficulty in obtaining homogenous stem/progenitor cells for transplantation studies and future clinical use. Moreover, the optimal types of cells for transplantation remain unclear. Studies in human tissues and in animal models of PVL showed that there is no lack of oligodendroglia progenitor cells (OPCs), because their proliferation is increased after PVL injury, but their maturation is largely delayed. Cell death is mainly seen in pre- myelinating OLs, but not in neurons. Hence, neuronal progenitors and OPCs may not be the optimal candidates in the PVL injury. Based on our preliminary data, here we propose to develop an astroglia-based cell therapy for neonatal brain injury. Our recent work has led to successful generation of immature astroglia from human embryonic stem cells (hESCs) in high homogeneity and purity (> 95%). We further demonstrated that transplantation of the hESC-derived astrocytes exhibited strong neuroprotective effects both in vitro and in vivo. Astrocytes are increasingly recognized as a crucial player in the myelination process during development and remyelination process after injury. We have been working on generation of human induced pluripotent stem cells (hiPSCs) from fibroblasts and their differentiation into OPCs for myelin regeneration and repair. A main advantage of hiPSCs with respect to hESCs is that they are an unlimited source of isogenic cells that might not be subjected to immune-rejection after transplantation. We have applied our efficient astroglial differentiation protocol o hiPSCs and generated hiPSC-derived immature astroglia. Our preliminary observation indicated that hiPSC-derived immature astrocytes promoted the maturation of OPCs into myelinating oligodendrocytes in vitro. Building upon these previous and preliminary results, we propose to examine whether transplantation of hiPSC-derived astrocytes promotes remyelination after neonatal brain injury in our established mouse PVL model, and the underlying mechanisms will also be explored. This novel study may lead to a new hiPSC-derived astroglia-based cell therapy for PVL, and will also provide new insight into the interaction between OLs and astrocytes, a previously understudied area of investigation. The scientific knowledge to be acquired through this project is of likely benefit to the development of stem cell based therapeutic strategies for treating human neurological disorders such as PVL.