环形RNA在腰椎间盘纤维环干细胞成骨分化过程中的调控作用及分子机制研究

Low back pain is a frequently occurred disease, which is related to the degeneration of intervertebral disc. Micro-injury of annulus fibrosus is an important manifestation of early degeneration in the intervertebral disc, but it is still lack of effective methods for the repair and treatment. In recent years, stem cell injection therapy has been paid so much attention, but there are some complications such as osteophyte formation by using exogenous stem cells. While endogenous stem cells have been discovered recently, whether they can be activated and committed differentiated for treatment is worth further study. In previous studies, we have successfully screened out endogenous stem cells in the annulus fibrosus of lumbar intervertebral disc, and set up the system for their osteogenic differentiation. Based on the previous research published by Cell about circular RNAs, we have found that a group of circular RNAs (including circRNA DKK1, and other candidate circular RNAs)was specifically related to osteogenic differentiation of these stem cells, by next generation sequencing and data analysis. Based on this, our project intends to study circular RNA and osteogenic differentiation phenotype of time-varying dynamic relationship, and to explore its potential molecular mechanisms during the osteogenic differentiation of lumbar annulus fibrosus stem cells in vitro. We hope this solution can accurately control the osteogenic differentiation process to provide adequate strength for repair and regeneration, and will not cause complications such as osteophyte. Thus, by using endogenous stem cells in the lumbar annulus fibrosus, we wish to provide a new approach for treating the degeneration and early injuries of lumbar intervertebral disc.

下腰痛是常见病，多与椎间盘退变有关。纤维环微损伤是椎间盘中早期退变的重要表现，但目前尚缺乏有效修复治疗的手段。近年来，干细胞再生修复治疗受到重视，但外源性干细胞治疗存在骨赘形成等问题。最新发现椎间盘内存在内源性干细胞，其能否被激活并增殖分化用于治疗值得深入研究。申请者前期在腰椎间盘纤维环组织中成功筛选出该类干细胞，并建立其成骨分化模型。借助我们此前研究环形RNA的成果和经验，通过分析转录组测序数据，申请者发现环形RNA表达谱系在该类干细胞成骨分化过程中有显著的变化，且部分环形RNA（如circRNA DKK1等）与成骨分化特异性相关。本项目拟在此基础上研究环形RNA在腰椎间盘纤维环内源性干细胞成骨分化过程中的调控作用及具体分子机制，以期能精确调控成骨分化过程，既促进内源性干细胞增殖分化修复纤维环微损伤，又不致引起骨赘等并发症，从而为内源性干细胞生物再生修复椎间盘退变损伤提供新的治疗策略。

纤维环是椎间盘的重要组成部分，多种因素导致纤维环发生微损伤是椎间盘早中期损伤退变的重要病理机制之一，但目前尚无很好的早期修复治疗手段。近年来，干细胞再生修复治疗研究的发展，使其很有希望成为治疗椎间盘退变损伤的新方向。研究表明，椎间盘纤维环中也存在有自身成体干细胞，但是该类细胞的生物学特性及其在椎间盘损伤退变中的角色作用尚不完全清楚。以往研究多采用外源性干细胞注射疗法来尝试修复椎间盘损伤退变，但可否通过激活椎间盘纤维环内源性干细胞的增殖分化来进行生物学治疗修复，将其作为一个新的治疗途径，尚需深入探索。研究者前期发现环形RNA分子可能参与了纤维环内源性干细胞的成骨诱导分化，在此基础上，通过本课题的开展，进一步完善了椎间盘纤维环原代内源性成体干细胞的分选扩增体系，并建立了不同程度退变椎间盘纤维环成体干细胞样本库，完善了该类细胞向成骨、成软骨、成脂肪定向分化的技术体系，为进一步认识该类成体干细胞在椎间盘损伤退变病理机制、寻找新的治疗靶点打下了扎实的基础。同时，研究者还发现环形RNA对椎间盘纤维环来源成体干细胞的成骨具有一定的影响，且环形RNA的表达变化可影响该类细胞的扩增，为进一步研究其在椎间盘损伤退变修复中的角色作用提供了新的视角。此外，研究者还深度分析了环形RNA在椎间盘纤维环来源成体干细胞向成骨、成软骨、成脂肪不同定向分化过程中表达特征及其分子网络关系，为深入探索环形RNA在椎间盘损伤退变疾病过程中的病理过程中的命运转归提供了新的思路。