炎性因子响应的环状RNA100290通过调控间充质干细胞的干性影响骨再生及机制研究

Mesenchymal stem cell (MSC) has been an important participant in the process of bone regeneration. The distinctive feature of MSC that different to the mature cells mainly lies in its “stemness”. In other words, MSC not only differentiate into various types of cells that involved in bone regeneration, but also supplies abundant seed cells for bone regeneration by consistent self-replication. CircRNA is one kind of functionally recognized endogenous non-coding RNA. Accordingly, circRNA is able to modulate gene expression and control cell function via multiple regulatory mechanisms. In spite of its well understanding in the regulations of developed cells, the modulatory effects of circRNA on stem cells remain unknown. Based on our previous findings that the inflammatory cytokines such as TNF-α impaired the “stemness” of MSC and the circRNA arraying results, we discovered that circ-RNA circ-100290 up-regulated in MSC in response to TNF-α exposure. Furthermore, the “stemness” of MSC and the MSC-based bone regeneration were partially rescued when the expression of circ-100290 in MSC was knocked-down. However, the study about the regulatory effects of circRNA on MSC “stemness” and the related mechanisms have never been revealed. Hence, this proposed study will mechanistically investigate the influence of circ-100290 on bone regeneration by regulating the “stemness” of MSC through studying the model of immune-related bone destruction and bone trauma. This study will contribute to theoretical accumulation in the field of bone regeneration and provide new theoretical guidance for the clinical application of MSC.

间充质干细胞(MSC)是骨再生的重要参与者，其与成骨细胞和骨细胞等成熟细胞的区别在于干性，即MSC既能分化为成熟细胞进行骨再生，又能不断自我复制，为骨再生保留充足的种子。环状RNA是一类生物学功能刚刚被认识的内源性非编码RNA，可通过多种机制调控基因表达，影响细胞功能。目前相关研究侧重环状RNA对成熟细胞的调节，有关其对干细胞的作用报道不多。我们前期研究表明TNF-α等炎性因子损害MSC干性，采用环状RNA芯片技术筛选发现MSC中的环状RNA100290响应炎性因子刺激而上调。敲低环状RNA100290后，MSC干性及骨修复能力有所恢复。而目前国内外研究未见环状RNA调节MSC干性及机制的报道。为此，本课题拟建立炎性骨损伤和骨创伤修复模型，深入研究环状RNA100290对MSC干性和骨再生的调节作用及机制。本课题将为骨再生研究提供理论积累，为MSC临床应用提供新的理论依据。

干细胞的干性是指干细胞不仅可以多向分化，而且可以自我复制的能力，维持干细胞必要的干性可以维持干细胞的数量和功能，为组织再生提供种子。circRNA100290是调节细胞增殖分化的重要环装RNA之一，但是其对于MSC干性的调控作用却报道不多。本课题已经完成了小鼠骨源MSC、HB-MSC、RA-MSC 和OA-MSC分离培养；已经完成环状RNA100290病毒的设计包装，并开展了功能实验；已经建立起了稳定高表达circRNA100290的MSC细胞模型以及cas-9技术介导的circRNA100290稳定敲除MSC 细胞模型；分析了circRNA100290过表达和敲除以后MSC内干性关键基因（Sox2, Oct4等）表达的变化。结果表明：circRNA100290有助于维持MSC 的干性，但是其调控骨再生修复的机制仍有待探索。