DRG engraftment of transduced mesenchymal stem cells to treat neuropathic pain

描述（由申请人提供）：神经性疼痛是常见的致残性疼痛。虽然对疼痛机制的理解已经进步，但可用的治疗仍然不足。拟议研究的总体目标是通过结合两种新方法来设计一种高效灵活的治疗系统。首先，靶向单个（或几个）背根神经节（DRG）的治疗将允许在节段基础上直接治疗感觉神经元，从而限制对健康感觉通路的副作用。其次，间充质干细胞（MSC）的移植提供了一个强大的机会，利用扩大病理生理学的理解。 具体而言，自体MSC是容易获得的，它们容易生长，它们在基因工程后高度能够分泌肽，并且这些细胞没有伦理或监管问题。初步数据表明，体外慢病毒转导通过许多繁殖循环在MSC中产生稳定的转基因表达，因为该载体将转基因插入宿主基因组中，并且MSC分泌比没有遗传修饰的MSC高得多的治疗肽水平。与使用直接病毒载体注射到患者体内的基因治疗方法不同，该策略避免了病毒的免疫原性和毒性作用，并允许在再植入之前在患者体外进行受控的高效转导，从而提高性能和安全性。 这项工作将发展这种新的治疗方法，在顺序的目标。首先，将使用大鼠作为受试者来表征MSC的必要剂量、它们的存活率和它们的分化命运。其次，重要的解剖学和生理学观察将评估MSC移植对内源性DRG细胞的影响，以确认MSC本身的植入没有有害影响。最后，概念验证实验将测量通过移植工程化的重组蛋白在大鼠神经损伤模型中治疗神经性疼痛的功效。 MSC进入DRG。在这些转化试验中使用的修饰的MSC将分泌胶质细胞源性神经营养因子（GDNF）或白细胞介素10，当通过其他途径递送时，其已经证明在预防或逆转神经性疼痛中的功效。将疼痛行为和细胞效应与其中DRG已注射仅表达报告基因（GFP）的MSC的动物以及未处理的对照进行比较。 完成拟议的工作将为工程MSC作为这些或其他镇痛肽在大型动物或人类受试者中的来源的治疗试验奠定基础。

DESCRIPTION (provided by applicant): Neuropathic pain is common and disabling. Although understanding of pain mechanisms has advanced, available treatments remain inadequate. The overall goal of the proposed research is to devise a highly effective and flexible treatment system by combining two novel approaches. First, therapy that targets a single (or several) dorsal root ganglia (DRGs) will permit direct treatment of sensory neurons on a segmental basis, thereby limiting side effects on healthy sensory pathways. Second, transplantation of mesenchymal stem cells (MSCs) provides a powerful opportunity to capitalize on expanding pathophysiological understanding. Specifically, autologous MSCs are readily available, they are easily grown, they are highly capable of secreting peptides after genetic engineering, and there are no ethical or regulatory issues with these cells. Preliminary data indicate that in vitro lentiviral transduction produces stable transgene expression in MSCs through many cycles of propagation, since this vector inserts the transgene into the host genome, and that MSCs secrete much higher levels of therapeutic peptides than they can without genetic modification. Unlike gene therapy approaches using direct viral vector injection into patients, this strategy avoids immunogenic and toxic effects of the virus, and permits controlled, highly efficient transduction outside the patient prior to reimplantation, thereby enhancing performance and safety. The proposed work will develop this new therapy in sequential Aims. First, the necessary dose of MSCs, their survival rates, and their differentiation fate will be characterized using rats as subjects. Second, important anatomical and physiological observations will evaluate effects of MSC transplantation on endogenous DRG cells to confirm that implantation of MSCs per se has no harmful effects. Finally, proof of concept experiments will measure the efficacy of treating neuropathic pain in a rat nerve-injury model, by transplantation of engineered MSCs into the DRG. The modified MSCs used in these translational trials will secrete either glial cell derived neurotrophic factor (GDNF) or interleukin 10, which have demonstrated efficacy in preventing or reversing neuropathic pain when delivered by other routes. Pain behavior and cellular effects will be compared to animals in which DRGs have been injected with MSCs that express only a reporter gene (GFP), and to untreated controls. Completion of the proposed work will establish the basis for therapeutic trials of engineered MSC as sources of these or other analgesic peptides in larger animals or human subjects.