基于FoxA2和TICRR的退变髓核细胞重编程在椎间盘修复中的作用和机制研究

髓核细胞退变导致的功能障碍是引起椎间盘退变的重要始动因素，因此从源头上改变髓核细胞的退变状态具有重大意义。退变髓核细胞从脊索样细胞转变而来，脊索样细胞具有较强的细胞增殖，成髓核分化及基质合成能力，因此利用细胞重编程技术将退变髓核细胞逆转为脊索样细胞将有望从源头上修复退变椎间盘，而组蛋白修饰是调控细胞重编程的关键机制。我们前期通过转录组测序筛选到FoxA2和TICRR可能是退变髓核细胞重编程的潜在靶点，而FoxA2其中可通过调控组蛋白H3K27me3脱甲基化提升染色质开放性，从而影响细胞重编程。因此本项目旨在前期基础上明确FoxA2和TICRR在退变髓核细胞重编程为脊索样细胞中的有效性和效率；阐明重编程不同阶段FoxA2和TICRR的具体作用，探究组蛋白H3K27me3脱甲基化调控的染色质开放性改变在细胞重编程中的调控机制；并在动物模型中评估重编程后的脊索样细胞修复退变椎间盘的效果和安全性。

Dysfunction caused by degeneration of nucleus pulposus cells (NPCs) is an important initiating factor of intervertebral disc (IVD) degeneration. Therefore, it is of great significance to fundamentally treat the degeneration of NPCs. Degenerative NPCs are derived from notochord-like cells which have strong ability in cell proliferation, nucleus pulposus-specific differentiation, and matrix synthesis, so reversing the degenerative NPCs into notochord-like cells with the technology of cell reprogramming is potential to fundamentally repair the IVD degeneration. In addition, histone modification is a key mechanism in cell reprogramming. We have already performed RNA-seq and screened FoxA2 and TICRR as potential targets for reprogramming of degenerative NPCs into notochord-like cells. FoxA2 can improve chromatin accessibility by regulating the demethylation of histone H3K27me3, and then affecting the reprogramming of degenerative NPCs. The aim of this project is to determine the effectiveness and efficiency of FoxA2 and TICRR in the reprogramming of degenerative NPCs into notochord-like cells, and clarify the specific roles of FoxA2 and TICRR at different stages of reprogramming, and investigate the regulatory mechanism of chromatin accessibility alteration induced by the demethylation of histone H3K27me3 in reprogramming. We also plan to evaluate the efficacy and safety of notochord-like cells in repairing degenerative IVDs in animal models.