Wnt信号通过激活YAP/TAZ和β-catenin调控雌激素受体表达的机制研究

Bone remodeling is the biological basis of orthodontic tooth movement. Crosstalk between Wnt signaling and estrogen receptor signaling synergically regulates bone remodeling; however, the specific mechanism remains unclear. Regarding Wnt signaling regulating expression of estrogen eceptors (ERs) as the entry point, we hypothesize that Wnt signaling regulates expression of ERs via activating YAP/TAZ and β-catenin during BMSCs osteogenic differentiation as well as the bone remodeling. To test this hypothesis, firstly, we establish the model of bone defect repair in rat to examine the correlation between Wnt signaling activation and ERs expression. Then, we progressively explore the mechanism of Wnt-YAP/TAZ and Wnt/β-catenin regulating the ERs expression through recombinant Wnt3a application, luciferase reporter assay, lentivirus transfection during osteogenic induction of BMSCs in vitro. In addition, we verify the mechanism of YAP/TAZ and β-catenin regulating ERs expression using organ culture model of femoral bones ex vivo. The implementation of this study will further unravel the crosstalk mechanism between Wnt signaling and estrogen receptor signaling, which will provide molecular evidences for the synergy of these two signaling pathways in regulating osteogenic differentiation of BMSCs and bone remodeling, and bring about new insights into safe and efficient orthodontic tooth movement as well as the translational application in bone loss diseases.

骨重塑是正畸牙移动的生物学基础，Wnt信号与雌激素受体（ERs）信号间串话协同调控骨重塑，但其机制尚未阐明。本课题以Wnt信号调控ERs表达为切入点，提出在BMSCs成骨向分化及骨重塑过程中，Wnt信号通过激活YAP/TAZ和（或）β-catenin调控ERs表达的科学假说。为验证该假说，我们拟先通过构建骨缺损修复模型探索Wnt信号激活与ERs表达的相关性，继而在体外BMSCs成骨向分化诱导培养中采用Wnt3a重组蛋白干预、荧光素酶报告基因检测、慢病毒转染等方法对Wnt-YAP/TAZ和Wnt/β-catenin通路调控ERs表达的机制及作用异同进行逐级反复论证，再结合股骨器官培养模型将体外机制进行体内验证。本课题的实施将深入揭示Wnt信号与ERs信号间的串话机制，为二者协同调控BMSCs成骨向分化及骨重塑提供分子依据，为安全高效正畸牙移动及骨缺失类疾病治疗的转化应用开辟新思路。

骨重塑是正畸牙移动的生物学基础，Wnt信号与雌激素受体(ER)信号间串话协同调控骨重塑，但其机制尚未阐明。本课题以Wnt信号调控ERs表达为切入点，提出在BMSCs成骨向分化及骨重塑过程中，Wnt信号通过激活YAP/TAZ和(或)β-catenin调控ERs表达的科学假说。我们通过对Wnt信号及YAP/TAZ和β-catenin的激活或抑制，采用Wnt3a重组蛋白干预、siRNA、Biotin探针、DNA Pulldown等方法对Wnt-YAP/TAZ和Wnt/β-catenin信号调控ERs表达的机制及作用进行逐级反复论证，研究发现Wnt信号可通过YAP/TEAD1和β-catenin/ LEF1直接与ERα基因启动子结合进而激活ERα表达，促进BMSCs成骨分化及矿物形成，且Wnt-YAP/TAZ信号和Wnt-β-catenin信号对ERα表达及BMSCs成骨分化具有协同促进作用。本课题的实施进一步揭示了Wnt信号与ER信号间的串话机制，为二者协同调控BMSCs成骨向分化及骨重塑提供分子依据，也为安全高效正畸牙移动及骨缺失类疾病治疗的转化应用开辟新思路。