Identification of mechano-sensitive pathways in intervertebral disc cells

椎间盘形成沿脊柱长度的软结缔组织关节，是脊柱稳定、负重和活动所必需的。椎间盘的主要功能是在机械负荷时充当减震器。它由不同但相互依赖的组织组成，包括中央髓核，它是高度水合的，并提供膨胀以承受压缩载荷，以及包含髓核并提供抗拉伸应变的外纤维环。尽管每天的机械负荷为椎间盘细胞提供了必要的反馈以维持组织的完整性，但过度的负荷通过激活椎间盘细胞的一系列不可逆转的变化而导致椎间盘退变，最终导致椎间盘无法履行其生理功能。因此，特定椎间盘细胞对机械负荷的反应对于维持椎间盘组织的功能至关重要。不同类型的机械载荷（来自正常运动和暴露于振动）对椎间盘不同细胞类型的影响尚不清楚，调控这些反应的细胞途径也是如此。

Intervertebral discs form the soft connective tissue joints located along the length of the spine - required for spinal stabilization, load bearing, and movement. The major function of the intervertebral disc is to act as a shock absorber during mechanical loading. It is composed of distinct yet interdependent tissues including the central nucleus pulposus, which is highly hydrated and provides turgor to withstand compressive loading, and the outer annulus fibrosus which contains the nucleus pulposus and provides resistance to tensile strain. Although daily mechanical loading provides necessary feedback to cells of the disc to maintain the tissue’s integrity, excessive loading contributes to disc degeneration by activating a cascade of non-reversible changes in disc cells that ultimately lead to an inability of the disc to fulfill its physiological function. The responses of specific disc cells to mechanical loading are therefore essential to maintaining a functional disc tissue. The effects of different types of mechanical loading (resulting from normal movement vs. exposure to vibration) on the distinct cell types of the disc are poorly understood, as are the cellular pathways that regulate these responses. The objective of these studies is to characterize the effects of mechanical loading on specific cell types of the disc, and explore which signaling pathways mediate the cellular response. We will use a genetically engineered mouse model that uses fluorescent cell markers to distinguish nucleus pulposus cells from annulus fibrosus cells. Cells grown in the lab will be subjected to mechanical loading in the form of either cyclic strain (physiological loading) or vibration (to model exposure to heavy machinery or vibration platforms) and the response of these cell types will be quantified through a series of experiments. These studies will give us a better fundamental understanding of how different cell types of the intervertebral disc respond to mechanical loading, information that is key to understanding how the disc maintains its structural integrity. Deciphering the pathways that control intervertebral disc mechanobiology will facilitate the development of tissue engineering strategies to recreate disc formation in vitro.