微纳米形貌通过诱发细胞应激反应调控细胞成骨分化的研究

The osteogenic differentiation is regulated by surface micro/nano topography of biomaterials whereas the exact mechanism is not fully elucidated yet. We have found that the endoplasmic reticulum stress and autophagy activity were significantly different among different micro/nano topographies in our previous study. It is reported that the cell membrane stress may happen after the lipid disequilibrium caused by membrane stretch. The endoplasmic reticulum stress and autophagy process are then activated to reestablish lipid homeostasis. Considering the direct effect of topography on cell membrane and the close interactions among endoplasmic reticulum, autophagy and cell function, we propose the hypothesis that the micro/nano topography may regulate osteogenic differentiation through direct induction of different cellular stress responses. Based on these, our project will try to detailedly figure out the membrane stress response, endoplasmic reticulum stress and autophagy profiles on micro/nano topographic surface by using cell and molecular biology techniques including morphological observation, fluorescent staining, western blot and gene intervention et al. In the meanwhile, their communication and relationships to osteogenic differentiation will also be analyzed. The project may help to deeply reveal the mechanism behind the regulation of cell function by surface topography of biomaterials.

生物材料表面微纳米形貌对细胞成骨分化具有调控作用，但微纳米形貌是如何直接调控成骨分化过程尚不清楚。本课题组前期研究发现细胞在不同微纳米形貌表面内质网应激和自噬水平存在显著差异；既往研究提示细胞膜受到微小作用力后磷脂分子失衡，诱发质膜应激反应，并通过内质网应激和自噬恢复稳态；考虑到微纳米形貌对细胞的最直接影响是施加在细胞膜上的不同作用力，以及质膜应激反应、内质网应激和自噬与成骨分化之间的交互作用，我们提出微纳米形貌通过直接诱发不同细胞应激反应调控细胞成骨分化功能的假说。在此基础上，本课题拟采用细胞形态学观察、荧光染色、蛋白印迹、基因干扰等细胞和分子生物学技术对细胞在微纳米形貌表面的质膜应激、内质网应激和自噬进行全面证实，并对它们之间的交互作用以及其与成骨分化之间的关系进行深入探索，以期进一步地解析生物材料表面形貌对细胞功能调控现象的本质。

生物材料表面微纳米形貌对细胞成骨分化具有调控作用，但微纳米形貌是如何直接调控细胞进行成骨分化过程尚未被阐释明晰。本课题组在前期研究中发现细胞在不同微纳米形貌表面的内质网应激和自噬水平存在显著差异，近些年来大量的研究提示内质网应激和自噬与细胞的成骨分化具有重要的内在联系，参与并决定了成骨分化的进程。在此基础上我们提出，微纳米形貌通过直接诱发不同细胞应激反应调控细胞成骨分化功能的假说。本课题采用细胞形态学观察、荧光染色、蛋白印迹、基因干扰等细胞和分子生物学技术对细胞在微纳米形貌表面内质网应激和自噬的发生进行了全面证实，明确了不同管径纳米管的微纳米形貌能够诱发不同程度的细胞应激反应，阐明了细胞膜表面的整合素-FAK信号通路与细胞下游应激反应发生间的相关性，并对内质网应激和自噬与成骨细胞分化、巨噬细胞极化之间的关系进行深入探索，进一步地阐释了生物材料表面微纳米形貌调控成骨细胞功能的本质，也为指导微纳米形貌设计提供了新的理论依据。