THE ROLE OF SCHWANN CELL SENESCENCE IN PERIPHERAL NERVE REGENERATION

施万细胞衰老在周围神经再生中的作用

• 批准号: 9059197
• 负责人: SUSAN E MACKINNON
• 金额: $ 41.23万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9059197
• 关键词: Affect; Allografting; Animal Model; Autologous Transplantation; Axon; Blood Vessels; Cell Aging; Cell Culture Techniques; Cell Transplants; Cells; Data; Distal; Environment; Frequencies; Goals; Green Fluorescent Proteins; Growth Inhibitors; Health; Histology; Image; Label; Lead; Length; Ligands; Measures; Mediating; Military Personnel; Modeling; Morbidity - disease rate; Natural regeneration; Nerve; Neurites; Neurons; Operative Surgical Procedures; Outcome; Peripheral nerve injury; Pharmacological Treatment; Population; Procedures; RNA Interference; Rattus; Recovery of Function; Reperfusion Therapy; Research; Research Project Grants; Role; Schwann Cells; Signal Transduction; Techniques; Testing; Therapeutic; Time; United States; Vascular Endothelial Growth Factors; axon growth; axon regeneration; experience; functional outcomes; functional restoration; gamma secretase; improved; in vivo; inhibitor/antagonist; lentivirally transduced; nerve gap; nerve injury; new therapeutic target; notch protein; operation; overexpression; peripheral nerve regeneration; reconstruction; regenerative; repaired; senescence; small hairpin RNA

 DESCRIPTION (provided by applicant): Peripheral nerve injuries are common and associated with devastating morbidity. Direct nerve repair without a graft is rarely possible and many techniques have been used to "bridge the gap". However, nerve injuries requiring long nerve grafts or constructs result in poor functional outcomes. All graft constructs (i.e. autografts, cadaveric allografts, acellular nerve allografts, and nerve conduits) have length limits for supporting regeneration. As the length of the graft construct increases, regeneration decreases until few or no axons reach the distal nerve. Our research demonstrates long nerve grafts accumulate significant quantities of senescent Schwann cells (SenSCs), with the presence of SenSCs preceding, not following, diminished axonal regeneration. Our recent data demonstrates SenSCs cause reduced axonal regenerative capacity in cell culture and in vivo. This data also suggests SenSCs may exert their effects on axons through the expression of Notch ligands. We hypothesize SenSCs impact axonal regeneration across nerve grafts. To test this hypothesis, we utilize animal models of nerve grafts that allow us to modify graft components including SenSC quantity, vascular reperfusion time, and Notch-ligand expression in both SenSCs and normal SCs. We determine how modifying these components impacts axonal regeneration across nerve grafts. The goal of this proposal is to establish the impact of SenSCs on axonal regeneration and functional recovery in long nerve grafts and provide a mechanism for reduced axonal growth due to SenSCs. We first determine the impact of SenSC quantity on axonal regeneration across nerve grafts. We then determine how improving vascular reperfusion (decreased vascular reperfusion time) affects axonal regeneration across nerve grafts and the accumulation of SenSCs. Our preliminary data identified increased expression of Notch ligands in long nerve grafts compared to short nerve grafts concomitant with decreased axonal regeneration and increased SenSC accumulation. As such, we determine the impact of Notch ligand expression by SenSCs on axonal regeneration across nerve grafts using overexpression and RNAi techniques targeting Notch ligand expression. The proposed plan will improve our understanding as to why axonal regeneration is reduced or fails in long nerve grafts and may lead to therapies, including novel therapeutic targets. The specific aims of this proposal are: Aim 1: Determine the impact of SenSCs in limiting regeneration across nerve grafts; Aim 2: Determine the impact of SenSC-mediated Notch ligand expression on axonal growth.

 描述（适用提供）：外周神经损伤很常见，并且与毁灭性的发病率有关。没有移植的直接神经修复是很少可能的，并且已经使用许多技术来“弥合差距”。但是，需要长神经移植或结构的神经损伤导致功能不佳。所有移植物构建体（即自体移植，尸体合金，大神经合金和神经管道）都有支撑再生的长度限制。随着移植物构建体的长度的增加，再生下降，直到几乎没有轴突到达远端神经为止。我们的研究表明，长长的神经移植物积累了大量的Senscent Schwann细胞（SENSC），而在轴突再生之前的Sensc存在下降。我们最近的数据表明，SENSC在细胞培养和体内导致轴突再生能力降低。该数据还表明，SENSC可以通过Notch配体的表达来执行其对轴突的影响。我们假设SENSC会影响跨神经移植物的轴突再生。为了检验这一假设，我们利用神经移植物的动物模型，使我们能够修改SENSC和正常SC中的SensC数量，血管再灌注时间和Notch-Ligand表达在内的图形组件。我们确定这些成分如何影响神经移植的轴突再生。该提案的目的是建立SENSC对长神经移植物中轴突再生和功能恢复的影响，并为由于Sensc而降低轴突生长提供了一种机制。然后，我们确定改善血管再灌注（减少血管再灌注时间）如何影响跨神经移植物和SENSC的积累的轴突再生。我们的初步数据确定了与短神经配体相比，与轴突再生减少和SENSC积累增加相比，长神经配体中缺口配体的表达增加。因此，我们使用针对Notch配体表达的过表达和RNAi技术来确定SENSCs通过SENSCs表达对轴突再生的影响。拟议的计划将提高我们对轴突再生为何在长神经移植中减少或失败的理解，并可能导致疗法，包括新的治疗靶点。该提案的具体目的是：目标1：确定SENSC在限制神经移植物再生中的影响； AIM 2：确定Sensc介导的Notch配体表达对轴突生长的影响。