Wnt/β-catenin信号通路在miR-155调控椎间盘基质代谢中的作用及其机制研究

Intervertebral disc degeneration is the common reason of degenerative disc diseases. It was reported that miR-155 inhibited the apoptosis of nucleus pulposus cells. However, the mechanism of the regulation of matrix metabolism in intervertebral disc by miR-155 remains unclear. Our results showed that lumbar disc degeneration appeared in the 6-month miR-155 knockout mouses and miR-155 inhibited the expression of transcription factor C/EBPβ and the related factor of Wnt/β-catenin signaling, APC and GSK3β.in nucleus pulposus cells in vitro. Moreover, knockdown of C/EBPβ suppressed the expression of GSK3β in nucleus pulposus cells. In addition, some articles showed that Wnt/β-catenin signaling regulated the expression of NF-κB signaling which regulated the matrix metabolism in breast tumor cells, et al. Therefore, we speculated that miR-155 regulate the matrix metabolism and in the process, the Wnt/β-catenin/NF-κB signaling mediated by C/EBPβ is very important. On the basis of above results, we will study the mechanism of matrix metabolism regulated by miR-155 in the clinical, animal and cellular level. And then we will evaluate the effect of C/EBPβ, Wnt/β-catenin and NF-κB signaling in the process of matrix metabolism in intervertebral disc regulated by miR-155. Through this project, we will further the etiology of intervertebral disc degeneration and provide the new method for the therapy of intervertebral disc degeneration.

椎间盘退变是椎间盘退变性疾病共同的病理基础，已有研究表明miR-155抑制椎间盘细胞的凋亡，但miR-155对椎间盘基质代谢的作用尚无文献报道。我们的前期实验显示6月龄miR-155基因敲除鼠腰椎间盘出现退变，miR-155可抑制C/EBPβ和Wnt/β-catenin通路因子APC、GSK3β的表达，且C/EBPβ调控GSK3β的表达，结合以往肿瘤细胞中Wnt/β-catenin通路可能通过NF-κB通路调控基质代谢的报道，我们推测，miR-155参与椎间盘基质代谢调控，且C/EBPβ介导的Wnt/β-catenin/NF-κB通路在其中起重要作用。本课题将在前期基础上从临床、动物、细胞水平证实miR-155调控椎间盘基质代谢，而后进一步研究C/EBPβ、Wnt/β-catenin和NF-κB通路在其中的作用。通过本研究，将进一步明确椎间盘退变的病理机制，并为其治疗开辟新思路和新途径。

椎间盘退变是椎间盘退变性疾病共同的病理基础，已有研究表明miR-155抑制椎间盘细胞 凋亡，但miR-155对椎间盘基质代谢的作用尚无文献报道。前期实验显示6月龄miR-155基因敲除鼠腰椎间盘出现退变，miR-155可抑制C/EBPβ和Wnt/β-catenin通路因子APC、GSK3 β的表达，且C/EBPβ调控GSK3β的表达，我们推测，miR-155参与椎间盘基质代谢调控，且C/EBP及Wnt/β-catenin通路在其中起重要作用。本课题从动物、 细胞水平证实miR-155调控椎间盘基质代谢，并进一步研究C/EBPβ、Wnt/β-catenin通路在其中的作用，明确椎间盘退变的病理机制，并为其治疗开辟 新思路和新途径。在本项目的资助下，已发表相关科研论著7篇，其中SCI收录7篇。同时，课题组有3名硕士研究生获得硕士学位。.具体研究结果含：.1. 1岁龄miR-155转基因鼠MRI未见腰椎椎间盘退变，1岁龄miR-155基因敲除鼠HE染色则可见椎间盘退变.2. miR-155能促进大鼠髓核细胞基质合成代谢，抑制基质分解代谢.3. TNFα/IL-1β可诱导大鼠髓核细胞C/EBPβ的mRNA及蛋白水平表达.4. miR-155降低大鼠髓核细胞C/EBPβ的mRNA及蛋白水平表达.5.干扰C/EBPβ表达能够模拟miR-155对TNFα/IL-1β诱导的大鼠髓核细胞基质分解代谢效应的抑制作用.6. miR-155降低大鼠髓核细胞TCF4的mRNA及蛋白水平表达，其通过直接与TCF4的3’UTR结合发挥其负性调控作用.7.RNA干扰大鼠和人髓核细胞TCF7L2表达后，均可上调髓核细胞基质II型胶原和蛋白聚糖蛋白的表达，是通过影响NF-KB通路起作用的。