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(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。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，例如在骨质疏松症的病因学或治疗骨质疏松症的新药物靶点方面。本研究提出了一种新的骨细胞-成骨细胞力学生物学的三维小梁骨移植共培养模型，该模型允许活的骨细胞被其天然的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型的三维松质骨共培养模型来检验一个中心科学假说，即动态变形负荷诱导OCys向OB发送合成代谢信号，通过骨细胞网络中的细胞内钙振荡促进骨形成，然后通过缝隙连接/半通道向OBS产生/分泌前列腺素E2(PGE2)。我们将检验以下工作假设：假设H1：PGE2的产生、骨形成的变化以及种植了原代牛OB的3D牛骨小梁的弹性模量依赖于OCys中依赖于钙调素激酶(CaMK)的钙振荡。假设H2：PGE2的产生、骨形成的变化和三维牛骨小梁骨的弹性模数取决于OCys中的缝隙连接/半通道连接蛋白43(Cx43)。假说H3：种植于3D松质骨中的OBS在动态变形载荷下的成骨反应和松质骨弹性模数的变化依赖于PGE2途径。利用这种新的松质骨共培养系统，可以在比以往更具生理学意义的条件下，在体外研究机械载荷下骨细胞和成骨细胞之间的相互作用：(1)当受到动态变形载荷时，骨细胞和成骨细胞都被包含并定位在其自然的三维松质骨环境中；(2)体外将骨细胞-成骨细胞机械转导的重要因素与骨功能联系起来，以评估骨形成和骨小梁的弹性模量；(3)利用复杂的分子生物学技术，分别对OCY和OB的生化途径进行选择性调控，这在体内是不可能实现的；(4)骨细胞和/或成骨细胞周围的微观力学环境将分别用标本特有的有限元模型进行量化。骨细胞力学转导的细胞和分子机制将获得新的见解，有助于我们对骨质疏松病因的总体理解，并可能导致旨在缓解或治疗骨质疏松症的治疗干预。 公共卫生相关性：新型三维(3D)活体骨小梁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。了解骨细胞和成骨细胞之间的细胞和分子力学转导途径有助于我们对骨质疏松症的病因有更全面的了解，并可能导致骨质疏松症的新的治疗方法。