circRNA-ITCH作为ceRNA吸附miRNA-214调控BMP2促进BMSCs成骨分化的机制研究

Osteoporosis (OP) has a high incidence, and it can lead to fracture easily, and the prevention, treatment and rehabilitation of OP are difficult. Insufficient osteogenic differentiation of BMSCs is key cause of OP. In the preliminary study of this program, applicant found that down-regulation of miR-214 can promotes BMSCs osteogenic differentiation by targeted increases BMP2. Recently, it have been reported that cir-ITCH can promotes osteogenic differentiation of periodontal ligament stem cells. In the Pre-Experiment, the applicant of this program found that the level of cir-ITCH in BMSCs of OP patients was lower than that of non-OP patients, and found that the level of cir-ITCH in BMSCs was increased in the process of osteoblastic differentiation of BMSCs, in addition, the applicant found that cir-ITCH could bind to miR-214 directly. Therefore, the applicant put forward a scientific hypothesis:"cir-ITCH can promotes BMSCs osteogenic differentiation by sponging miR-214 as ceRNA to regulate BMP2 expression". For this purpose, we intend to test the correlation between the expression of cir-ITCH/miR-214/BMP2 and clinical features of OP; and we are going to study the specific mechanism that cir-itch promotes BMSCs osteogenic differentiation by competitive combination with miR-214 to increase BMP2 expression by RIP and other experimental methods at the cell level; moreover, we will test the results at the animal level. The results of this study will provide important guiding significance for the prevention, treatment and rehabilitation of OP.

骨质疏松症（OP）发病率很高且易导致骨折，防治和康复难度大。BMSCs成骨分化不足是关键病因，申请人前期研究发现下调miR-214可靶向升高BMP2促进BMSCs成骨分化。最新文献报道，cir-ITCH可促进牙周膜干细胞成骨分化。在预实验中，申请人发现OP患者BMSCs的cir-ITCH水平低于非OP患者，且cir-ITCH水平在BMSCs成骨分化过程中逐渐升高，并发现cir-ITCH能与miR-214直接结合。因此申请人提出科学假说：“cir-ITCH可作为ceRNA吸附miR-214调控BMP2促进BMSCs成骨分化”。为此，本项目拟检测cir-ITCH/miR-214/BMP2表达与临床特征的相关性；在细胞水平使用RIP等实验手段研究cir-ITCH竞争性结合miR-214上调BMP2促进BMSCs成骨分化的具体机制；并在动物水平进行验证。研究结果对OP的防治和康复具有重要指导意义。

骨质疏松症（OP）是最普遍的原发性骨性疾病，是一种日益增长的医疗保健负担。本研究旨在阐明circ-ITCH调控骨质疏松症成骨分化的功能作用和机制。在骨质疏松小鼠和患者中，Circ-ITCH和yes相关蛋白1（YAP1）水平下调，但miR-214水平上调。在成骨诱导过程中，下调circ-ITCH可抑制碱性磷酸酶（ALP）活性、矿化结节形成以及runt相关转录因子2（RUNX2）、骨桥蛋白（OPN）和骨钙素（OCN）的表达。此外，miR-214是circ-ITCH的一个靶点，miR-214的敲除可能会抑制sh-circ-ITCH对成骨分化的调控作用。此外，miR-214通过下调YAP1来抑制hBMSCs的成骨分化。最后，在体内实验中表明，过表达circITCH可以改善去卵巢小鼠的成骨能力。综上所述，circ-ITCH通过吸附miR-214上调YAP1的表达，促进骨质疏松症患者的成骨分化。Circ-ITCH可作为治疗骨质疏松症的新靶点。