The role of notochord derived signaling, mechanical force generation and AF derived Tgfβ signaling on intervertebral disc formation

项目总结/摘要 椎间盘（IVD）损伤，如突出和退变，可导致腰痛，这是一个 全球残疾的主要原因。成功重现IVD结构的组织工程策略 可恢复功能，减轻IVD损伤负担。然而，椎间盘发育不是 这是一个很好理解的问题，阻碍了关键分子因子的治疗靶向。最初，IVD中心， 髓核是由连续的脊索通过 脊索细胞从未来的椎骨体中出来，进入椎间盘。IVD纤维状外观， 纤维环，起源于围绕脊索并通过 排列的胶原纤维的沉积和细胞外基质的产生。从分子上讲，脊索是 分泌型形态原Sonic Hedghehog（Shh）的表达，纤维环表达生长因子TGF β。 这项拨款将测试脊索在IVD发展的两个不同阶段的必要性：增殖， AF中肌动蛋白纤维的形成。第二个目的将确定机械力产生的作用， 肌球蛋白、肌动蛋白丝形成和Rho通路激活对AF形成的影响。最后一个目标决定了 TGF β信号在AF分化中的定量表达和必要性，包括细胞排列和 细胞外基质沉积该项目利用小鼠遗传学来操纵分子线索， 用原位杂交、免疫组织化学和RNA测序等方法研究了分子和表型效应。 该项目的成功完成将提供对分子和机械驱动因素的见解， 椎间盘形成和产生的见解，可用于开发疼痛的IVD损伤的修复。

PROJECT SUMMARY / ABSTRACT Intervertebral disc (IVD) injury such as herniation and degeneration can result in low back pain which is a leading cause of global disability. Tissue engineering strategies which successfully recapitulate IVD structure could restore function and reduce the burden of IVD injury. However, intervertebral disc development is not well understood, hindering the therapeutic targeting of key molecular factors. Initially, the IVD center, the nucleus pulposus, arises from the segmentation of the continuous notochord through the movement of notochordal cells out of the future vertebra body and into the intervertebral disc. The IVD fibrous exterior, the annulus fibrosus, arises from sclerotomal cells which surround the notochord and differentiatiate through the deposition of aligned collagen fibers production of extracellular matrix. Molecularly, the notochord is a source of the secreted morphogen Sonic Hedghehog (Shh), and annulus fibrosus expresses the growth factor Tgfβ. This grant will test the necessity of the notochord in two different stages of IVD development: proliferation, and actin fiber formation in the AF. The second aim will determine the role of the mechanical force generation, myosin, actin filament formation and Rho pathway activation on AF formation. The last aim determines the quantitiative expression and necessity of Tgfβ signaling in AF differentiation including cell alignment and extracellular matrix deposition. This project utilizes mouse genetics to manipulate molecular cues, and assays the molecular and phenotypic effects with in situ hybridization, immunohistochemistry and RNA sequencing. The successful completion of the project will provide insights on molecular and mechanical drivers of intervertebral disc formation and yield insights which can be used for developing repairs for painful IVD injury.