The Osteoblastic Monolayer as a 'Gatekeeper' in Bone

成骨细胞单层作为骨骼的“看门人”

• 批准号: 6662547
• 负责人: MELISSA L KNOTHE TATE
• 金额: $ 7.38万
• 依托单位: CLEVELAND CLINIC FOUNDATION
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-23 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6662547
• 关键词: bone development; bone metabolism; calcium flux; cell line; cell membrane; confocal scanning microscopy; diffusion; electrical conductance; electrophysiology; glucose transport; insulin; membrane channels; membrane model; membrane permeability; membrane potentials; model design /development; osteoblasts; parathyroid hormones; phosphates

DESCRIPTION (provided by applicant): The broad, long-term objective of this project is to understand the barrier properties of a confluent osteoblastic monolayer, which will provide insight into the role of the osteoblastic lining cell system in the physiology and pathophysiology of bone. This layer of cells that covers all resting surfaces in bone is expected to serve a "gatekeeper" role in the development of hydraulic and electric resistance as well as passage of material, e.g., water, nutrients, ions, waste products and growth factors, into and out of bone tissue. It is this gatekeeper role that lends bone the ability to function as an organ within vertebrate systems. The Specific Aims of this project are (1) to study the permeability characteristics of water as well as specific nutrients (glucose), ions (calcium and phosphate) and growth factors (insulin, PTH) in a static environment, allowing for simple diffusion and pressure head differences between the apical and basal surfaces as well as (2) in dynamic environments exposed to cyclic flow regimes on the apical and basal surfaces of the membrane. For each of these aims, the effect of PTH on barrier function will be studied in situ. The research design is to measure baseline values for hydraulic and electrical conductivity as well as concentration gradients of water, nutrient (glucose), ion (Ca and P) and growth factor transport (insulin, and PTH or a fluorescent tagged, inert analog such as dextran) due to diffusion and static pressure across the osteoblast cell membrane. A confluent monolayer of osteoblasts from the paraosteosarcoma cell line UMR-106-01-BSP will be used as a model system. To address the first aim, pressure will be provided through a pressure head on either side of the membrane in an Ussing chamber. To address the second aim, an innovative dual flow chamber system will be built, tested and implemented as a physiological cell culture model. In both cases, electrical resistance and hydraulic conductance will be measured across the membrane, and glucose, calcium, phosphate, PTH and insulin will be measured in the apical and basal media. The proposed project represents an innovative departure from conventional understanding of bone physiology. This study is expected to provide insight into new strategies for treatment of bone diseases such as osteoporosis and osteoarthritis.

描述（由申请人提供）： 该项目的广泛、长期目标是了解汇合的成骨细胞单层的屏障特性，这将深入了解成骨细胞衬里细胞系统在骨的生理学和病理生理学中的作用。覆盖骨骼所有静止表面的这层细胞预计将在液压和电阻的发展以及物质（例如水、营养物、离子、废物和生长因子）进入骨骼的过程中发挥“看门人”的作用。并脱离骨组织。正是这种看门人的角色使骨骼能够作为脊椎动物系统中的器官发挥作用。该项目的具体目标是（1）研究静态环境中水以及特定营养物质（葡萄糖）、离子（钙和磷酸盐）和生长因子（胰岛素、PTH）的渗透特性，允许简单的扩散和渗透。顶面和底面之间的压头差异以及（2）暴露于膜顶面和底面循环流态的动态环境中。对于这些目标中的每一个，都将在原位研究 PTH 对屏障功能的影响。研究设计是测量水力和电导率的基线值以及水、营养物（葡萄糖）、离子（Ca 和 P）和生长因子运输（胰岛素和 PTH 或荧光标记的惰性类似物，例如右旋糖酐）由于穿过成骨细胞膜的扩散和静压而产生。来自副骨肉瘤细胞系 UMR-106-01-BSP 的成骨细胞汇合单层将用作模型系统。为了实现第一个目标，将通过尤斯室中膜两侧的压头提供压力。为了实现第二个目标，将构建、测试并实施创新的双流室系统作为生理细胞培养模型。在这两种情况下，将测量跨膜的电阻和水力电导，并测量顶端和基底介质中的葡萄糖、钙、磷酸盐、PTH 和胰岛素。拟议的项目代表了对骨生理学传统理解的创新背离。这项研究有望为治疗骨质疏松症和骨关节炎等骨疾病的新策略提供见解。