微纳米形貌通过影响细胞的机械记忆调控细胞成骨分化的研究

Cells can sense and integrate mechanical signals presented by the surface of biomaterials, which regulate the osteogenic differentiation. Micro/nano-textured topography highly mimics the natural bone tissue structure, and possesses a strong ability to induce osteogenesis. Previous studies have found that micro/nano-textured topography can trigger endoplasmic reticulum stress and autophagy, which promote the osteogenic differentiation; although the endoplasmic reticulum stress and autophagy were transiently activated, it determined the osteogenic differentiation. Nature materials has reported that stem cells possess mechanical memory. We speculate that cells remember the micro/nano-textured topography, and YAP/TAZ store the mechanical information. Base on the research of endoplasmic reticulum stress and autophagy in promoting osteogenic differentiation, this project intends to use cell morphology observation, osteogenesis-related staining, immunofluorescence, Western Blot, gene intervention and other cell and molecular biology techniques to fully confirm the cell mechanical memory of micro/nano-textured topography, and to further explore the characteristics of such mechanical memory and its role in osteogenic differentiation, so that to reveal the mechanism of cell memory of micro/nano-textured topography in regualting osteogenic differentiation.

细胞可以感知并整合生物材料表面的机械信号，影响成骨分化。微纳米形貌高度模拟了天然骨组织结构，具有较强的诱导成骨能力。前期研究发现，微纳米形貌可诱发细胞产生内质网应激和自噬，对细胞成骨分化起正向促进作用；虽然内质网应激和自噬仅一过性被激活，但却能决定细胞的成骨分化能力。Nature materials曾报道干细胞具有机械记忆特点。我们推测，细胞能对微纳米形貌产生机械记忆，并通过YAP/TAZ存储机械记忆。本课题拟在前期对内质网应激和自噬促进微纳米形貌诱导成骨分化等相关研究的基础上，采用细胞形态学观察，成骨相关染色，免疫荧光染色，蛋白印迹，基因干扰等细胞及分子生物学技术全面证实细胞对微纳米形貌的机械记忆，并对机械记忆的特点及其对细胞成骨分化的影响进行深入探索，揭示细胞对微纳米形貌的记忆在成骨分化中的作用机制。

微纳米形貌可高度模拟天然骨组织结构，具有较强的诱导成骨能力。在本研究中，我们探究了MNT在诱导骨间充质干细胞（BMSCs）成骨分化中的作用和机制。通过将大鼠BMSCs光滑钛片(PT)或MNT样品的表面上培养。我们发现，与PT相比，MNT5（5V阳极氧化）显着增强了BMSCs的成骨分化，骨钙素(OCN)和碱性磷酸酶(ALP)的表达显著上调。通过转录组测序结合生物信息学分析，揭示了MNT诱导的成骨分化过程中BMSCs中不同的转录本表达模式和信号通路。从机制上讲，我们发现在MNT5诱导的体外成骨分化过程中，两个与成骨分化相关的通路被激活：WNT5b通路和整合素α1（ITGA1）。这两个基因均可通过激活YAP/TAZ信号通路促进BMSCs的成骨分化。我们的发现从细胞机械记忆的角度对材料表面MNT促进细胞成骨分化的机制进行探究，为深入研究生物材料表面物理形貌对细胞生物学行为影响的机制开辟一条新的途径。