长链非编码RNA HOTAIR作为ceRNA对成骨细胞功能的调控及其在失重性 骨丢失中的作用研究

Weightlessness induced bone loss is one of the key medical problems during space flight. Non-coding RNAs play an imporant role in the regulation of bone metabolism. Our previous research showed miR-214 promoted bone loss induced by weightlessness via targeting ATF4. In our recent studies, we have found that the expression of HOTAIR was up-regulated in the process of osteoblast differentiation. With increasing the expression of HOTAIR in osteoblasts, the protein level of ATF4 was accordingly significantly up-regulated, at the same time the activity of osteoblast was also obviously up-regulated. By bioinformatics analysis, we found there were several binding sites of miR-214 in HOTAIR. This data suggested HOTAIR may act as ceRNA to regulate osteoblast activity. In this study, we will investigate the changes of HOTAIR in the process of weightlessness induced bone loss, explore the role of HOTAIR in osteoblast function and its mechanisms in regulating the function of osteoblast as ceRNA. By using osteoblast specific HOTAIR transgenic mice, we will investigate whether HOTAIR could ameliorate weightlessness induced bone loss. This project will disclose a new molecular mechanism in regulating osteoblast differentiation and function from the view of lncRNA by ceRNA, and provide new insights of countermeasure and defense for weightlessness induced bone loss.

失重性骨丢失的发生机制是航天医学的关键问题。非编码RNA在骨代谢平衡中发挥着重要的调控作用。其中，miR-214通过靶向ATF4抑制成骨细胞的功能加剧失重性骨丢失的发生。最近我们的研究发现lncRNA HOTAIR在成骨细胞分化过程中表达明显升高，过表达HOTAIR可以增加ATF4蛋白水平、促进成骨细胞的活性。生物信息学分析显示HOTAIR与miR-214存在多个潜在结合位点，提示HOTAIR可通过ceRNA方式调控成骨细胞的功能。本课题将深入研究失重性骨丢失发生过程中HOTAIR的表达变化规律，解析HOTAIR对成骨细胞分化及功能的影响，阐释其以ceRNA方式对成骨细胞功能的调控作用及机制，通过成骨细胞特异表达HOTAIR的转基因小鼠，探讨其在失重性骨丢失中的对抗作用。该研究将从ceRNA的角度揭示lncRNA对成骨细胞功能的调控作用及机制，为失重性骨丢失的对抗和防护提供新的策略和靶点。

失重性骨丢失的发生机制是航天医学的关键问题之一。非编码RNA在骨代谢平衡中发挥着重要的调控作用。本课题利用小鼠尾吊和细胞回转模型，深入研究失重性骨丢失发生过程中HOTAIR的表达变化规律，发现HOTAIR在尾吊和回转导致的成骨细胞功能降低模型当中表达水平显著降低。在成骨细胞中通过过表达和敲低实验发现HOTAIR是促进成骨细胞活性的RNA分子，生物信息学分析显示HOTAIR与miR-214存在多个潜在结合位点，机制研究发现HOTAIR通过竞争性结合miR-214，抑制其对成骨关键转录因子ATF4的翻译调控作用，促进成骨细胞的功能。在体内，利用成骨细胞特异的Ocn-HOTAIR转基因小鼠研究发现，HOTAIR在体内通过结合miR-214促进ATF4蛋白水平，进而促进小鼠骨形成和成骨细胞的功能，并且转基因小鼠能够一定程度缓解尾吊导致的骨丢失。本研究从ceRNA的角度揭示lncRNA对成骨细胞功能的调控作用及机制，为失重性骨丢失的对抗和防护提供新的策略和靶点。