Mechanobiology of 3D Trabecular Bone Explants

3D 小梁骨外植体的力学生物学

• 批准号: 7808303
• 负责人: X. Edward GUO
• 金额: $ 32.38万
• 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 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7808303
• 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; Hand; 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）本质上是三维的（3D），成熟的骨细胞包裹在3D矿化的细胞外骨基质中。近年来的研究表明，骨细胞在检测机械信号和维持骨骼完整性方面发挥着重要作用。这些作用具有重要的临床意义，如骨质疏松症的病因学或骨质疏松症治疗的新药物靶点。本文提出了一种用于骨细胞-成骨细胞力学生物学的新型3D骨小梁骨外植体共培养模型，该模型允许活骨细胞被其原生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）相互连接。我们建议使用这种新颖的3D骨小梁共培养模型来验证一个中心科学假设，即动态变形载荷诱导OCYs向OBs发送合成代谢信号，通过骨细胞网络中的腔内钙[Ca2+]i振荡促进骨形成，随后通过间隙连接/半通道向OBs产生/分泌前列腺素E2 （PGE2）。我们将测试以下工作假设：假设H1：含有原代牛OBs种子的3D牛小梁骨外植体的PGE2产生、骨形成的变化和弹性模量依赖于OCYs中钙调蛋白激酶（CaMK）依赖的Ca2+振荡。假设H2：含有原代牛骨的3D牛骨小梁骨外植体的PGE2生成、骨形成的变化和弹性模量取决于OCYs中的间隙连接/半通道连接蛋白43 （Cx43）。假设H3：在动态变形载荷和骨小梁弹性模量变化作用下，3D骨小梁植入OBs的成骨响应依赖于PGE2通路。利用这种新的骨小梁外植体共培养系统，可以在体外条件下研究机械载荷下骨细胞和成骨细胞之间的相互作用，这比以前可能的条件更具有生理学相关性：(1)当受到动态变形载荷时，骨细胞和成骨细胞都包含在其原生的3D骨小梁环境中并定位；(2)将在体外评估骨小梁的功能性骨形成和弹性模量，将骨细胞-成骨细胞机械转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选择性地操纵OCYs和OBs的生化途径，这在体内是无法实现的；(4)将使用特定样本的有限元模型分别量化骨细胞和/或成骨细胞周围的微力学环境。新见解将获得关于骨细胞机械转导的细胞和分子机制，将有助于我们对骨质疏松症病因的一般理解，并可能导致旨在减轻或治疗骨质疏松症的治疗干预。