CircRNA23通过RBP调控软骨细胞功能在骨关节炎发病中的作用及分子机制研究

The pathogenesis of osteoarthritis (OA) remains unknown but it has been found that the imbalance of synthesis and degradation of cartilage extracellular matrix plays a key role in the pathogenesis and development of OA. Cicular RNA (circRNA) is noted for its high stability and strong tissue specificity. By high-throughput sequencing we found that there was significantly up-regulation of circRNA23 in OA chondrocytes and we confirmed its circularization by RT-PCR and Rnase R experiments. It was detected that there was up-regulation of circRNA23 in articular cartilage and blood of OA patients. Over-expression of circRNA23 could regulate the synthesis and degradation of extracellular matrix in cartilage by regulating RNA binding protein (RBP). This study will complete clinical specimen detection, clarify the relationship between circRNA23 and OA; assess its feasibility of being an early diagnostic marker of OA. Furthermore, we will combine with the OA chondrocytes and animal models to investigate the roles of circRNA23 and RBP in the regulation of the function of chondroctyes and the effect of inhibiting cartilage degeneration, explore the effect and molecular mechanism of that cricRNA23 regulate chondrocytes’ function via RBP in the pathogenesis of OA, which aims at providing new treatment targets and experimental evidences for early diagnosis and intervention of OA.

骨关节炎（OA）的具体发病机制尚未明确，但软骨细胞外基质合成与降解失衡是OA发生发展的关键病理环节。环状RNA（circRNA）具有稳定性高、组织特异性强等特点。我们通过高通量测序发现：circRNA23在OA患者软骨细胞中表达显著上调，经RT-PCR及Rnase R实验证实其环性；circRNA23在OA患者软骨组织和血液中表达上调；过表达circRNA23通过调控RNA结合蛋白（RBP）明显影响软骨细胞外基质的合成与降解。本项目拟进一步完善临床标本检测，阐明circRNA23与OA之间的关系，评估其作为OA早期诊断标志物的可行性；结合OA细胞和动物模型，进一步探索circRNA23、RBP对关节软骨细胞功能的调控及对关节软骨退变的抑制作用；探讨circRNA23通过RBP调控软骨细胞功能在OA发病中的具体分子机制，旨在为OA的早期诊断和早期干预提供可靠的新靶标和实验依据。

骨性关节炎（OA）是一种常见的慢性疾病，以软骨组织退变和软骨细胞的凋亡为特征。近年来研究发现，环状RNA（circRNA）在OA发生发展过程中发挥重要的作用。本项目研究发现：在人和小鼠OA模型膝关节的软骨组织中，环状RNA HIPK3（circHIPK3）的表达明显降低。通过蛋白组学分析，发现circHIPK3在软骨细胞中调控线粒体凋亡。通过实验我们发现circHIPK3是通过介导线粒体的膜蛋白—对氧磷酶2（PON2）的表达调控线粒体性凋亡。进一步通过生物信息学分析和验证，明确了circHIPK3是通过吸附miR-30a-3p调控PON2的表达，即circHIPK3通过介导miR-30a-3p—PON2轴调控线粒体性凋亡，进而参与调控OA的发生和发展。此外，项目研究发现circHIPK3还可通过与miR-10a-5p结合，调控同源盒基因3（HOXA3）的表达，参与软骨细胞的增殖和凋亡过程，促进OA的进展。另外，在项目研究过程中，我们发现生物钟基因Clock通过调控软骨细胞的衰老过程参与OA的进展。在软骨细胞中，Clock除了调控生物节律之外，还通过参与线粒体自噬活动，进而调控软骨细胞的衰老过程。由于circRNA具有作为良好的生物标志物的特点，我们在OA和类风湿性关节炎（RA）中初步探讨了circRNA作为生物学标志物的可行性。在RA患者研究中发现hsa_circ-0140271在RA女性的外周血单核细胞中特异性高表达，并且在RA早期明显升高，还与IL-6、IL-8、TNF-α等表达有相关性。以上研究结果揭示了circHIPK3是调控OA软骨细胞功能的关键分子之一，并且circRNA拥有作为潜在的OA及RA生物学诊断标志物的可行性。此外，生物钟基因Clock是调控软骨细胞衰老的关键分子之一。