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（由申请人提供）：周围神经损伤是常见的，并与毁灭性的发病率。不使用移植物直接修复神经是不可能的，许多技术已被用于“桥接差距”。然而，需要长神经移植物或结构的神经损伤导致不良的功能结果。所有移植物结构（即自体移植物、尸体同种异体移植物、脱细胞神经同种异体移植物和神经导管）都具有支持再生的长度限制。随着移植物结构长度的增加，再生减少，直到很少或没有轴突到达远端神经。我们的研究表明，长神经移植物积累了大量的衰老雪旺细胞（SenSC），SenSC的存在是在轴突再生减少之前，而不是之后。我们最近的数据表明SenSC在细胞培养和体内引起轴突再生能力降低。该数据还表明SenSC可以通过Notch配体的表达对轴突发挥其作用。我们假设SenSC影响神经移植物的轴突再生。为了验证这一假设，我们利用神经移植物的动物模型，使我们能够修改移植物成分，包括SenSC的数量，血管再灌注时间，和Notch配体在SenSC和正常SC中的表达。我们确定如何修改这些组件的影响轴突再生神经移植。该提案的目标是确定SenSC对长神经移植物中轴突再生和功能恢复的影响，并提供SenSC减少轴突生长的机制。我们首先确定SenSC数量对神经移植物轴突再生的影响。然后，我们确定改善血管再灌注（减少血管再灌注时间）如何影响神经移植物的轴突再生和SenSC的积累。我们的初步数据表明，与短神经移植物相比，长神经移植物中Notch配体的表达增加，伴随着轴突再生减少和SenSC积累增加。因此，我们使用过表达和靶向Notch配体表达的RNAi技术来确定SenSC表达Notch配体对神经移植物轴突再生的影响。该计划将提高我们对长神经移植物中轴突再生减少或失败的原因的理解，并可能导致治疗，包括新的治疗靶点。该提案的具体目标是：目标1：确定SenSC在限制神经移植物再生中的影响;目标2：确定SenSC介导的Notch配体表达对轴突生长的影响。