Mechanisms of Cell/Surface Interaction

描述(申请人提供)：这项研究的目标是确定调节细胞和组织对与骨接触的生物材料的反应的机制。这项建议解决了牙科和骨科植入物的临床需求，这些植入物能够促进快速的骨整合和更早的加载时间，特别是当放置在因患者的疾病或生理损害的骨中时。通过了解表面形态和化学如何调节细胞反应，可以开发出通过结构信号控制细胞行为的材料，而不需要药物修饰。我们使用结构化表面作为模型来定义哪些微米、亚微米和纳米尺度的特征和化学调节特定的细胞反应，并研究涉及的潜在机制，长期目标是创造合理的仿生材料，促进正常组织的再生和修复。我们的实验假设是，表面的物理和化学性质决定了整合素的表达，影响细胞信号和对调节成骨形成的系统因素的反应，以及成骨细胞分化的自分泌和旁分泌介质。此外，基质上间充质干细胞和骨祖细胞的变化通过产生调节血管生成和成骨的因子来影响种植体周围骨的形成。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的化学成分的新型材料在体外和体内检测成骨细胞的行为。我们将使用我们团队开发的新成像技术来询问单个细胞下的底物形态和化学成分，这使得我们能够识别表达特定mRNAs的活细胞。我们将使用稳定沉默的细胞系，这些细胞系减少了介导成骨细胞对材料表面微结构反应的特定蛋白质的表达，我们将使用体外共培养模型以及体内小鼠和大鼠模型，以筛选体外确定的结构特征的临床应用，重点关注老年和骨量减少动物骨愈合过程中的血管生成/血管生成。我们将(1)开发和表征可能调节MSC分化和成骨细胞表型表达的纳米级、表面特征和化学功能；(2)确定介导表面设计特征差异效果的机制，包括整合素和Want信号的作用；以及(3)评估表面设计的变化如何调节衰老和去卵巢小鼠和大鼠体内种植体周围骨的形成。

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.