Tissue Engineered Rostral Migratory Stream for Directed Neuronal Replacement

项目总结 由于创伤性脑损伤(TBI)导致的慢性残疾影响了2%的总人口，神经元丢失是 通常被认为是永久性的，因为成年哺乳动物大脑的神经再生能力有限。 目前还没有批准的治疗方法来改善脑损伤后的恢复，创新的方法可以 增强神经再生是迫切需要的。耐人寻味的是，新的神经元在 室下区(SVZ)，然后经嘴引导至嗅球/束(可能还有纹状体) 用于集成到现有电路的迁移流(RMS)。最近的出版物表明，SVZ 神经母细胞可以被重定向到损伤处，分化成区域特定的神经细胞类型，整合到 回路，并改善成年啮齿动物的功能恢复，但这是一种指导和增强 神经母细胞向皮损的迁移尚未确定。为了应对这一挑战，我们已经组建了一个 由干细胞专家、神经生物学家、临床医生和组织工程师组成的多学科团队开发 第一个以解剖学为灵感设计的微组织，在结构和功能上模仿脑胶质管 均方根。在一项令人兴奋的突破中，我们的团队开发了新的微组织工程技术，以促进 星形胶质细胞自组装成纵向排列的束，概括了胶质细胞的组织 RMS的试管。到目前为止，我们已经对这种组织工程鸡冠迁移流(TE-RMS)进行了生物浓缩 使用啮齿动物来源的星形胶质细胞和人类干细胞来源的星形胶质细胞，重要的是，我们有 研究表明，TE-RMS直接促进未成熟神经元在体外和体外的排列和迁移 活着。在目前的方案中，我们将首先验证TE-RMS作为体外试验床的有效性，以阐明其机制 神经前体迁移和细胞命运决定(目标1)。然后我们将测试TE-RMS的能力 体内分流内源性神经前体细胞和修复实验性脑损伤大脑皮层的实验研究 大鼠脑损伤模型(目标2)。为此，将在急性伤害期后立体定向注射TE-RMS，以 从SVZ到受损组织，以及迁移的神经元重定向到重新填充皮质区域， 将评估与残存电路的功能集成以及行为恢复的便利性。最后，由于 作为临床翻译的第一步，我们将进行体外和体内研究，以验证所建立的TE-RMS 利用成人牙龈干细胞来源的星形胶质细胞建立 最终从容易获得的细胞来源创建自体、患者来源的植入物(目标3)。这个 TE-RMS概括了大脑自身传递和整合新神经元的方法。因此，处决 这些目标将大大推进翻译生物工程方法，能够提供有针对性的 以及在神经损伤和/或变性后持续的细胞替换。我们的团队处于独特的地位，可以 提供一种可行但高度创新的神经再生方法，可对 患者遭受脑损伤的其他难以治愈的后果。

PROJECT SUMMARY Chronic disability due to traumatic brain injury (TBI) affects 2% of the total population, and neuronal loss is generally considered permanent, owing to limited capacity for neuroregeneration in the adult mammalian brain. There are currently no approved treatments for improving recovery after TBI, and innovative approaches to enhance neuroregeneration are desperately needed. Intriguingly, new neurons are generated in the subventricular zone (SVZ) and then guided to the olfactory bulb/tract (and possibly striatum) via the rostral migratory stream (RMS) for integration into existing circuitry. Recent publications have demonstrated that SVZ neuroblasts can be redirected into lesions, differentiate into region-specific neuronal cell types, integrate into circuitry, and improve functional recovery in adult rodents, but a translational strategy to direct and enhance neuroblast migration into lesions has yet to be established. To address this challenge, we have assembled a multi-disciplinary team of stem cell specialists, neurobiologists, clinicians, and tissue engineers to develop the first anatomically-inspired microtissue designed to structurally and functionally emulate the glial tube of the RMS. In an exciting breakthrough, our team developed novel microtissue engineering techniques that promote the self-assembly of astrocytes into longitudinally aligned bundles that recapitulate the organization of the glial tube of the RMS. To date, we have biofabricated this Tissue Engineered Rostral Migratory Stream (TE-RMS) using rodent derived astrocytes as well as human stem cell derived astrocytes and, importantly, we have shown that the TE-RMS directly facilitates the alignment and migration of immature neurons in vitro and in vivo. In the current proposal, we will first validate the TE-RMS as an in vitro test bed to elucidate mechanisms of neuronal progenitor migration and cell fate determination (Aim 1). We will then test the ability of the TE-RMS to divert endogenous neuronal progenitors in vivo and repair damaged cerebral cortex following experimental TBI in rats (Aim 2). In this Aim, the TE-RMS will be stereotaxically microinjected after the acute injury period to span from the SVZ into lesioned tissue, and the redirection of migrating neurons to repopulate cortical areas, functional integration with residual circuitry, and facilitation of behavioral recovery will be assessed. Finally, as a first step towards clinical translation, we will perform in vitro and in vivo studies to validate the TE-RMS built using astrocytes derived from stem cells harvested from adult human gingiva to develop methods for the eventual creation of autologous, patient-derived implants from an easily accessible cell source (Aim 3). The TE-RMS recapitulates the brain's own method for delivery and integration of new neurons. Thus, the execution of these Aims will significantly advance a translational bioengineering approach capable of providing targeted and sustained cell replacement following neurotrauma and/or degeneration. Our team is uniquely positioned to provide a feasible, yet highly innovative neuroregenerative approach that can have a significant impact on patients suffering from the otherwise intractable consequences of TBI.