Correlating and Quantifying Mechanically-induced Bone Cell Microdamage

描述（由申请人提供）：骨破坏是许多骨相关疾病的中心主题，如骨质疏松症、颌骨骨坏死、应力性骨折和骨质溶解。了解骨在细胞水平上对机械负荷的反应对于消除这些疾病，以及改善骨折愈合和牵引成骨结果，开发组织工程骨替代品和改进植入物设计至关重要。目前的力学传导研究模型不足以研究骨细胞感知和协调对机械刺激的反应的基础科学机制，因此改进的力学传导模型至关重要。微系统技术提供了一个重大的改进，现有的mechanotransduction模型，使多细胞和细胞间的相互作用进行研究，在小细胞群体，同时消除时间和空间的限制。使用微系统方法，可以开发模型，使关键的细胞活动能够在生理上模拟。这项研究利用这项技术开发了一个 机械过载致骨细胞微损伤模型。具体而言，目前声称的理论，机械损伤是由骨细胞，然后协调骨重建活动的感觉进行测试。使用最近开发的新型微加载平台，骨细胞将受到损伤诱导水平的机械应变。将评估作为树突状过程破坏与细胞活力的函数的骨细胞损伤，并收集菌株产生的可溶性活性，并定量sclerostin和Dickkopf-1。此外，条件培养基将从这些损伤诱导应变水平产生，并用于研究损伤信号传递的机制。也就是说，使用微通道技术，骨细胞在通信完整和缺陷的环境将受到条件培养基从机械损伤的骨细胞在浓度依赖性的方式和直接可溶性活性与间接细胞通信的影响，在损伤信号传递将进行调查。鉴于微系统在骨骼研究领域的新颖性，这项工作将汇集两个专门从事机械传导和微系统的实验室。这两个实验室都有资格获得AREA（R15）支持。该项目适合考虑区域资助，因为它符合许多预期目标，包括“试点研究和可行性研究”，“开发和测试新的研究技术”和“展示研究能力的独立项目”。本研究的短期目标是利用一种新型的微加载平台来研究骨细胞的局部机械过载为特定部位的骨重建提供动力的基础科学机制，并展示微系统在骨研究中的力量和潜力。长期目标是通过提高仿生能力来扩展这些平台，以解决与骨骼领域相关的广泛临床应用，包括用于骨骼疾病诊断和检测的芯片实验室系统。 公共卫生相关性：本研究旨在了解骨重建对机械损伤的反应机制和途径。具体而言，本研究调查骨细胞骨细胞在感知机械损伤和局部传递该信号以引起骨吸收/形成中的作用。了解骨重塑的机制，使利用这一知识开发新的骨质疏松症和骨坏死治疗;改善骨折愈合和骨科和颅面植入物的固定;开发生物反应器，以帮助骨替代品的功能组织工程;并开发新的实验室模型和“芯片实验室”传感器在代谢性骨病检测和治疗效果。

DESCRIPTION (provided by applicant): Bone destruction is a theme central to many bone-related conditions such as osteoporosis, osteonecrosis of the jaw, stress fractures and osteolysis. Understanding the response of bone at the cellular level to mechanical loading is critical to eradicating these conditions, as well as improving fracture healing and distraction osteogenesis outcomes, developing bone substitutes for tissue engineering, and improving implant designs. Current mechanotransduction research models are ill-equipped to study the basic science mechanisms by which bone cells sense and coordinate a response to mechanical stimulation and improved mechanotransduction models are essential. Microsystems technology offers a major improvement over existing mechanotransduction models by enabling multicellular and intercellular interactions to be studied in small cell populations while removing temporal and spatial limitations. With a Microsystems approach models may be developed that enable critical cellular activity to be physiologically simulated. This study utilizes this technology to develop a model of osteocyte microdamage induced by mechanical overload. Specifically, the currently purported theory that mechanical damage is sensed by the osteocyte which then coordinates bone remodeling activity is tested. Using a recently developed, novel microloading platform, osteocytes will be subjected to damage-inducing level of mechanical strain. Osteocyte damage as a function of dendritic process destruction versus cell viability will be assessed and soluble activity resulting from the strain will be collected and quantified for sclerostin and Dickkopf-1. n addition, the conditioned medium will be generated from these damage-inducing strain levels and used to investigate mechanisms of damage signal transmission. That is, using microchannel techniques, osteocytes in communication-intact and -deficient environments will be subjected to conditioned medium from mechanically-damaged osteocytes in a concentration-dependent manner and the effects of direct soluble activity versus indirect cellular communication in damage signal transmission will be investigated. Given the novel nature of Microsystems in the bone research field, this work will bring together two laboratories specializing in Mechanotransduction and Microsystems. Both laboratories are eligible for AREA (R15) support. This project is appropriate for consideration of AREA funding as it meets many of the intended goals, including 'pilot study and feasibility research', 'development and testing of new research techniques' and a 'discrete project demonstrating research capability'. The short-term goals of this research are to utilize a novel microloading platform to investigate the basic science mechanisms by which localized, mechanical overload of osteocytes provide the impetus for site-specific bone remodeling and to demonstrate the power and potential of Microsystems in bone research. The long-term goals are to expand these platforms with increasing biomimicry capabilities to address a wide range of clinical applications relevant to the bone field including lab-on-a-chip systems for bone disease diagnostics and detection. PUBLIC HEALTH RELEVANCE: This research is aimed at understanding the mechanisms and pathways by which bone remodels in response to mechanical damage. Specifically, this research investigates the role the osteocyte bone cells play in sensing mechanical damage and locally transmitting this signal to bring about bone resorption/formation. Understanding the mechanisms by which bone remodels enables exploitation of this knowledge to develop novel osteoporosis and osteonecrosis treatments; improve fracture healing and fixation of orthopedic and craniofacial implants; develop bioreactors to aid in functional tissue engineering of bone substitutes; and, develop new laboratory models and 'lab-on-a-chip' sensors in metabolic bone disease detection and treatment efficacy.