Orexin/OX1R通过Akt/mTOR/FoxO3调控成骨细胞自噬及其在骨质疏松中的作用

With the acceleration of ageing of the population process, the incidence of osteoporosis increases year by year. Low osteogenesis caused by osteoblast dysfunction is considered to be the main mechanisms mediated by age and hormone deficiency. Autophagy plays an important role in osteoblast metabolism. Our preliminary study found that: 1. orexin A inhibited MC3T3-E1 osteoblast differentiation through the orexin receptor 1 (OX1R). 2. Orexin A inhibited osteoblast autophagy. We hypothesized that the inhibitory effect of orexin A on osteoblast autophagy was involved in its inhibition of osteoblast differentiation and further affected bone mass. In this study, we constructed a model of silencing "OX1R" and autophagy-related "ATG7" gene and knockout mice to study the effects of orexin A / OX1R on autophagy and its role in osteoblast differentiation, mineralization and bone mass from molecular, cellular and whole animal levels. Using immunoblotting, immunofluorescence, luciferase reporter gene and other methods, we investigate the molecular mechanisms responsible for the effects (Akt/mTOR and Akt/FoxO3 pathways). The aim of this study was to provide relevant experimental basis and new molecular targets for the improvement of osteoblast function and prevention and treatment of osteoporosis .

随着人口老龄化的进程增加，骨质疏松的发病率逐年上升。成骨细胞功能障碍导致的骨形成不足被认为是介导年龄和激素缺乏引起骨质疏松的主要机制之一。自噬在成骨细胞代谢过程中发挥重要作用。我们前期研究发现：①增食欲素A（orexin A）通过增食欲素受体1（OX1R）抑制MC3T3-E1成骨细胞分化；②Orexin A抑制成骨细胞自噬。我们推测，orexin A对成骨细胞自噬的抑制作用参与到其抑制成骨细胞分化的过程中，并进一步影响骨量。本研究拟构建沉默"OX1R"及自噬相关“ATG7”基因的细胞株及基因敲除小鼠模型，从分子、细胞及整体动物水平研究orexin A/OX1R对自噬的影响及其在成骨细胞分化、矿化和骨量中的作用，采用免疫印迹、免疫荧光、荧光素酶报告基因等研究相应分子机制（AKT/mTOR及AKT/FoxO3两条通路），旨在为改善成骨细胞功能、防治骨质疏松提供相关实验基础和新的分子靶标。