Mechanisms of Cell/Surface Interaction

描述（由申请人提供）：本研究的目的是确定调节细胞和组织对骨界面生物材料反应的机制。该提案解决了牙科和骨科植入物的临床需求，这些植入物可促进快速骨整合和更早的加载时间，特别是当植入受患者疾病或生理影响的骨中时。通过了解表面形态和化学如何调节细胞反应，可以开发通过结构信号控制细胞行为的材料，而不需要进行药理学修饰。 我们使用结构化表面作为模型来定义哪些微米，亚微米和纳米级特征和化学物质调节特定的细胞反应，并研究所涉及的潜在机制，长期目标是创造合理的仿生材料，促进正常组织再生和修复。我们的实验假设是，表面的物理和化学性质决定整合素的表达，影响细胞信号传导和对调节骨生成的系统性因素以及成骨细胞分化的自分泌和旁分泌介质的反应。此外，基质上的间充质干细胞（MSC）和骨祖细胞的变化通过产生调节血管生成和骨生成的因子来影响种植体周围骨形成。为了验证这一假设，我们建议使用具有纳米级特征和良好控制化学的新型材料来检查成骨细胞的体外和体内行为。我们将使用我们小组开发的新成像技术询问单个细胞下的底物形态和化学，这使我们能够识别表达特定mRNA的活细胞。我们将使用稳定沉默的细胞系，这些细胞系具有介导成骨细胞对材料表面微结构的反应的特定蛋白质的表达减少，并且我们将使用体外共培养模型以及体内小鼠和大鼠模型，这些模型允许我们筛选体外鉴定的结构特征的临床效用，重点关注老年和骨质疏松动物骨愈合期间的血管生成/血管生成。我们将（1）在纳米尺度上开发和表征可能调节MSC分化和成骨细胞表型表达的表面特征和化学功能;（2）确定介导表面设计特征差异效应的机制，包括整合素和Want信号的作用;和（3）评估表面设计的变化如何在衰老和卵巢切除的小鼠和大鼠体内介导骨植入物骨形成。

DESCRIPTION (provided by applicant): The goal of this research is to determine the mechanisms that regulate cell and tissue responses to biomaterials that interface with bone. This proposal addresses the clinical need for dental and orthopedic implants that promote rapid osteointegration and earlier loading times, particularly when placed in bone compromised by disease or physiology of the patient. By understanding how surface morphology and chemistry modulate cell response, materials may be developed that control cell behavior through structural signaling, without the need for pharmacologic modification. We use structured surfaces as models to define which micron-, submicron-, and nanoscale features and chemistry regulate specific cell responses and to study the underlying mechanisms involved, with the long-term goal of creating rational biomimetic materials that facilitate normal tissue regeneration and repair. Our experimental hypothesis is that physical and chemical properties of a surface determine integrin expression, influencing cellular signaling and response to systemic factors that regulate osteogenesis and to autocrine and paracrine mediators of osteoblast differentiation. Moreover, changes in mesenchymal stem cells (MSCs) and osteoprogenitor cells on the substrate influence peri-implant bone formation through production of factors that modulate angiogenesis and osteogenesis. To test this hypothesis, we propose to examine osteoblast behavior in vitro and in vivo using novel materials with nanoscale features and well controlled chemistries. We will interrogate the substrate morphology and chemistry under individual cells using new imaging technology developed in our group, which permits us to identify living cells expressing specific mRNAs. We will use stably silenced cell lines that have reduced expression of specific proteins that mediate the response of osteoblasts to material surface microstructure and we will use an in vitro co-culture model as well as in vivo mouse and rat models that permit us to screen the clinical utility of the structural features identified in vitro, focusing on vasculogenesis/angiogenesis during bone healing in aged and osteopenic animals. We will (1) develop and characterize at the nanoscale, surface features and chemical functionalities that may modulate MSC differentiation and osteoblast phenotypic expression; (2) determine the mechanisms that mediate the differential effects of surface design features, including the role of integrins and Want signaling; and (3) assess how changes in surface design mediate peri- implant bone formation in vivo in aging and ovariectomized mice and rats.