Regenerative potential of embryonic notochordal nucleus pulposus progenitors

摘要 腰椎间盘退变是一系列的细胞、结构和力学变化。 这被强烈地认为是腰痛的原因之一。中央髓核(NP)参与了 这种退行性级联的启动，其中蛋白多糖含量的下降和与之相关的 静水压力损害了NP有效接触周围纤维环的能力，并 在椎骨之间均匀地分配和传递压缩载荷。对治疗的迫切需要 用于通过直接寻址底层寻址恢复盘结构和机械功能的盘退化 生物原因。开发有效的椎间盘退变生物治疗的一个关键挑战是 需要概括一下组成组织的结构复杂性和专门的细胞外基质， 这些细胞由多种发育谱系的细胞组成。在这里，我们建议通过以下方式应对这一挑战 直接应用发展范式建立优化的生物盘再生系统 策略。胚胎和出生后的视盘形成由来自脊索的细胞调节。这些细胞 分泌一系列生长因子，调节细胞迁移、增殖、分化和细胞外 基质沉积，并最终直接导致NP本身。因此，人们对…有强烈的兴趣 识别脊索细胞分泌因子并应用于制定改进的治疗策略 光盘再生。研究脊索细胞再生潜力的理想阶段是当它们 最积极地促进胚胎和出生后早期的椎间盘发育。因此，总体来说 这项建议的目的是建立胚胎脊索来源的再生潜力 髓核祖细胞(NDCs)。具体地说，我们将定义生长因子表达谱 利用转录组全序列分析胚胎和出生后视盘发育关键阶段的NDCS (RNA-Seq)，并直接建立作为发育阶段函数的NDCs的再生潜力 使用体内的小鼠椎间盘退变模型。这项工作的结果将为 优化以细胞和生长因子为基础的治疗方法，以促进椎间盘再生。

Abstract Lumbar intervertebral disc degeneration is a cascade of cellular, structural and mechanical changes that is strongly implicated as a cause of low back pain. The central nucleus pulposus (NP) is implicated in the initiation of this degenerative cascade, where decreasing proteoglycan content and an associated reduction in hydrostatic pressure impair the ability of the NP to effectively engage the surrounding annulus fibrosus and to evenly distribute and transfer compressive loads between the vertebrae. There is a critical need for therapies for disc degeneration that restore disc structure and mechanical function by directly addressing the underlying biological causes. A key challenge to developing effective biological treatments for disc degeneration is the need to recapitulate the structural complexity and specialized extracellular matrix of the component tissues, which comprise cells of multiple developmental lineages. Here we propose to address this challenge by directly applying developmental paradigms to establish an optimized biological disc regeneration strategy. Embryonic and postnatal disc formation is regulated by cells derived from the notochord. These cells secrete an array of growth factors that regulate cell migration, proliferation, differentiation and extracellular matrix deposition, and ultimately, directly give rise to the NP itself. There is therefore intense interest in identifying notochordal cell-secreted factors and applying them to develop improved therapeutic strategies for disc regeneration. The ideal stage to investigate the regenerative potential of notochordal cells is when they are most actively contributing to embryonic and early postnatal disc development. Therefore the overall objective of this proposal is to establish the regenerative potential of embryonic, notochord-derived nucleus pulposus progenitor cells (NDCs). Specifically, we will define the growth factor expression profile of NDCs at key stages of embryonic and postnatal disc development using whole transcriptome sequencing (RNA-Seq), and directly establish the regenerative potential of NDCs as a function of developmental stage using an in vivo mouse model of disc degeneration. The results of this work will provide a roadmap for optimizing cell and growth factor-based therapeutics for disc regeneration.