Mechanobiology of 3D Trabecular Bone Explants

3D 小梁骨外植体的力学生物学

• 批准号: 8130788
• 负责人: X. Edward GUO
• 金额: $ 35.5万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8130788
• 关键词: Affect; Applications Grants; Biochemical; Biochemical Pathway; Bone Matrix; Ca(2+)-Calmodulin Dependent Protein Kinase; Calcium; Cattle; Cells; Cilia; Clinical; Coculture Techniques; Connexin 43; Dinoprostone; Elements; Environment; Etiology; Extracellular Matrix; Gap Junctions; In Vitro; Knockout Mice; Knowledge; Lead; Life; Link; Liquid substance; Mature Bone; Mechanics; MicroRNAs; Modeling; Molecular; Molecular Biology Techniques; Morphology; Nitrites; Osteoblasts; Osteocytes; Osteogenesis; Osteoporosis; Oxides; PTGS2 gene; Pathway interactions; Pharmacologic Substance; Positioning Attribute; Process; Production; Relative (related person); Research; Resistance; Role; Signal Transduction; Skeleton; Specimen; Stimulus; Study Subject; Study models; System; Tail Suspension; Technology; Testing; Therapeutic; Therapeutic Intervention; Tissues; Transgenic Mice; Work; bone; bone cell; bone loss; extracellular; in vivo; inhibitor/antagonist; insight; intercellular connection; kinase inhibitor; novel; novel therapeutics; public health relevance; receptor; response; sensor; substantia spongiosa

DESCRIPTION (provided by applicant): Osteocytes (OCY) are intrinsically three-dimensional (3D), mature bone cells encased in 3D mineralized extracellular bone matrix. Recent studies indicate the critical roles of osteocytes in detecting mechanical signals and maintaining skeleton integrity. These roles have significant clinical implications, such as in the etiology of osteoporosis or new pharmaceutical targets for osteoporosis treatment. A novel 3D trabecular bone explant co-culture model for osteocyte-osteoblast mechanobiology in this proposal allows for live osteocytes to be surrounded by their native extracellular matrix environment and to interconnect with osteoblasts (OB) through intercellular processes in the canaliculi channels. We propose to use this novel 3D trabecular bone co-culture model to test a central scientific hypothesis that that dynamic deformational loading induces OCYs to send anabolic signals to OBs to promote bone formation through intraceluar calcium [Ca2+]i oscillations in osteocytic network, followed by prostaglandin E2 (PGE2) production/secretion via gap junctions/hemi-channels to OBs. We will test the following working hypotheses: Hypothesis H1: PGE2 production, changes in bone formation, and elastic modulus of 3D bovine trabecular bone explants with seeded primary bovine OBs depend on calmodulin kinase (CaMK) dependent Ca2+ oscillations in OCYs. Hypothesis H2: PGE2 production, changes in bone formation, and elastic modulus of 3D bovine trabecular bone explants with seeded primary bovine OBs depend on the gap junctions/hemi-channels connexin 43 (Cx43) in OCYs. Hypothesis H3: Bone formation response of OBs seeded in 3D trabecular bone explants under dynamic deformational loading and changes in elastic modulus of trabecular bone depend on PGE2 pathway. With this new co-culture system of trabecular bone explants, the interaction between osteocytes and osteoblasts under mechanical loading can be investigated in vitro under conditions that are more physiologically relevant than previously possible: (1) both osteocytes and osteoblasts are included and positioned in their native 3D trabecular bone environment when subjected to dynamic deformational loading; (2) functional bone formation and elastic modulus of trabecular bone will be assessed in vitro, linking important factors in osteocyte-osteoblast mechanotransduction to bone functions; (3) selectively manipulating biochemical pathways in OCYs and OBs independently with sophisticated molecular biology technique, which cannot be achieved in vivo, and (4) micromechanical environments surrounding osteocytes and/or osteoblasts will be quantified, respectively, using specimen specific finite element models. New insights will be gained regarding cellular and molecular mechanisms of bone cell mechanotransduction and will contribute to our general understanding of the etiology of osteoporosis, and may lead to therapeutic interventions aimed at the mitigation or treatment of osteoporosis. PUBLIC HEALTH RELEVANCE: The novel three-dimensional (3D) live trabecular bone explant co-culture model will be used to quantify important biochemical pathways between osteocytes and osteoblasts under dynamic deformational loading. The understanding of cellular and molecular mechanotransduction pathways between osteocytes and osteoblasts contributes to our general understanding of the etiology of osteoporosis and can lead to new therapeutic treatment of osteoporosis.

描述（由申请人提供）：骨细胞（OCY）本质上是三维（3D）成熟骨细胞，包裹在 3D 矿化细胞外骨基质中。最近的研究表明骨细胞在检测机械信号和维持骨骼完整性方面发挥着关键作用。这些作用具有重要的临床意义，例如骨质疏松症的病因学或骨质疏松症治疗的新药物靶点。该提案中用于骨细胞-成骨细胞力学生物学的新型 3D 小梁骨外植体共培养模型允许活骨细胞被其天然细胞外基质环境包围，并通过小管通道中的细胞间过程与成骨细胞 (OB) 互连。我们建议使用这种新颖的 3D 小梁骨共培养模型来测试一个中心科学假设，即动态变形载荷诱导 OCY 向 OB 发送合成代谢信号，通过骨细胞网络中的细胞内钙 [Ca2+]i 振荡促进骨形成，然后通过间隙连接/半通道到 OB 产生/分泌前列腺素 E2 (PGE2)。我们将测试以下工作假设： 假设 H1：接种原代牛 OB 的 3D 牛小梁骨外植体的 PGE2 产生、骨形成变化和弹性模量取决于 OCY 中钙调蛋白激酶 (CaMK) 依赖性 Ca2+ 振荡。假设 H2：接种原代牛 OB 的 3D 牛小梁骨外植体的 PGE2 产生、骨形成变化和弹性模量取决于 OCY 中的间隙连接/半通道连接蛋白 43 (Cx43)。假设 H3：动态变形载荷下 3D 小梁骨外植体中接种的 OB 的骨形成反应和小梁骨弹性模量的变化取决于 PGE2 途径。利用这种新的小梁骨外植体共培养系统，可以在比以前更生理相关的条件下在体外研究机械负载下骨细胞和成骨细胞之间的相互作用：（1）当受到动态变形负载时，骨细胞和成骨细胞都被包含并定位在其天然3D小梁骨环境中； (2) 体外评估骨小梁的功能性骨形成和弹性模量，将骨细胞-成骨细胞机械传导的重要因素与骨功能联系起来； （3）利用复杂的分子生物学技术独立选择性地操纵 OCY 和 OB 中的生化途径，这是体内无法实现的；（4）将使用样本特定的有限元模型分别量化骨细胞和/或成骨细胞周围的微机械环境。将获得关于骨细胞力转导的细胞和分子机制的新见解，并将有助于我们对骨质疏松症病因学的一般理解，并可能导致旨在减轻或治疗骨质疏松症的治疗干预措施。 公共健康相关性：新型三维（3D）活体小梁骨外植体共培养模型将用于量化动态变形载荷下骨细胞和成骨细胞之间的重要生化途径。对骨细胞和成骨细胞之间的细胞和分子力传导途径的了解有助于我们对骨质疏松症病因学的总体了解，并可能导致骨质疏松症的新治疗方法。