Complement and Osteoporosis

补体和骨质疏松症

• 批准号: 8293594
• 负责人: JAMES E DENNIS
• 金额: $ 38.77万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2013-01-07
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8293594
• 关键词: Accounting; Address; Affect; Biological Assay; Bone Marrow; Bone Marrow Cells; Bone Resorption; C57BL/6 Mouse; Cells; Ceramics; Complement; Complement 1q; Complement 3; Complement Activation; Complement Factor D; Complement Receptor; Complement component C1; Complex; Equilibrium; Estrogens; Goals; Hematopoietic; Hematopoietic stem cells; Homeostasis; Human; Immune; Immunology; Implant; In Vitro; Knockout Mice; Laboratories; Lead; Link; Mediating; Mesenchymal Stem Cells; Methods; Modeling; Mus; Osteoblasts; Osteoclasts; Osteogenesis; Osteoporosis; Ovariectomy; Pathway interactions; Postmenopausal Osteoporosis; Postmenopause; Production; Regulation; Role; Signal Transduction; Stem cells; Structure; Testing; Time; Tissues; Transplantation; Umbilical Cord Blood; Wild Type Mouse; X-Ray Computed Tomography; base; bone; bone loss; bone turnover; cell type; clinically relevant; complement deficiency; complement system; cytokine; deprivation; dosage; drug development; effective therapy; implantation; in vivo; inhibitor/antagonist; interest; novel; novel strategies; osteogenic; prevent; progenitor; receptor; research study; skeletal; transcription factor

DESCRIPTION (provided by applicant): Recent results in our laboratories have revealed a new and unexpected relationship between the complement system and post-menopausal bone loss, which has the potential to lead to new therapies for osteoporosis. These studies revealed that mice lacking the C3 component of the complement system were protected from bone loss after ovariectomy (OVX), as shown by micro-computed tomography (microCT) analysis. Our in vitro studies revealed that bone marrow cells from complement receptor-deficient mice had decreased capacity to differentiate into functional osteoclasts. Further, inhibition of complement signaling suppressed human osteoclast differentiation from hematopoietic progenitors. Based on these results, it is hypothesized that the complement system is a key regulator of bone balance and a potential target for the treatment of osteoporosis. To address this hypothesis, two Aims are proposed. Aim 1 will examine which complement activation pathway is involved, and how complement and complement receptor deficiency impact in vivo bone turnover by assessing bone structure in several OVXed complement knockout mice (Factor D-/-, C1q-/-, MBL-/-, C3-/-, C3aR-/- ,C5aR-/-, and C3aR-/-C5aR-/-) and wild type (WT) controls; microCT and bone histomorphometry will be the primary readouts. Aim 1 also will examine the role of local complement production in the regulation of bone balance using cross-implantation studies where mesenchymal stem cells (MSC) form ectopic bone in porous ceramic carriers. Aim 2 will test the use of complement receptor inhibitors as a means of preventing osteoporosis both in WT mice and humanized mice. WT (C57BL/6) mice, human umbilical cord blood stem cell-implanted NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice, human MSC-implanted NSG mice, and both human umbilical cord blood stem cell and MSC-implanted NSG mice will be OVXed, treated, and assessed by microCT and bone histomorphometry. A novel aspect of the Aim 1 studies is the use of ectopically formed bone from MSCs isolated from the knockout mice that are then implanted into WT mice, and vice versa, which are then assayed for histomorphometric bone parameters - this allows for determination of the role of local complement deficiency of the MSCs on bone formation and loss, and also probes the effect of complement deficiency in hematopoietic cells when WT MSCs are implanted into the complement knockout mice. The complement receptor antagonists treatment experiments in Aim 2 using WT mice and different humanized mice are the most clinically relevant, and will address the potential of using these inhibitors for treating or preventing osteoporosis in humans. These studies will clarify how diminished complement signaling affects osteoblast and osteoclast differentiation in estrogen deprivation induced bone loss. The long-term goal of these studies is to develop new therapies to treat or prevent osteoporosis. PUBLIC HEALTH RELEVANCE: This project will study the role of complement in regulating bone turnover in osteoporosis, which has the potential of opening up complement as a new target for developing novel, effective therapies against osteoporosis.

描述（由申请人提供）：我们实验室的最新结果揭示了补体系统与绝经后骨质流失之间存在一种新的、意想不到的关系，这有可能带来骨质疏松症的新疗法。这些研究表明，微计算机断层扫描 (microCT) 分析显示，缺乏补体系统 C3 成分的小鼠在卵巢切除 (OVX) 后可以免受骨质流失。我们的体外研究表明，补体受体缺陷小鼠的骨髓细胞分化为功能性破骨细胞的能力下降。此外，补体信号传导的抑制抑制了人类破骨细胞从造血祖细胞的分化。基于这些结果，推测补体系统是骨平衡的关键调节剂，也是骨质疏松症治疗的潜在靶点。为了解决这一假设，提出了两个目标。目标 1 将通过评估几只 OVX 补体敲除小鼠（因子 D-/-、C1q-/-、MBL-/-、C3-/-、C3aR-/-、C5aR-/- 和 C3aR-/-C5aR-/-）和野生型 (WT) 对照的骨结构，检查涉及哪种补体激活途径，以及补体和补体受体缺乏如何影响体内骨转换； microCT 和骨组织形态计量学将是主要读数。目标 1 还将利用间充质干细胞 (MSC) 在多孔陶瓷载体中形成异位骨的交叉植入研究来检查局部补体产生在骨平衡调节中的作用。目标 2 将测试补体受体抑制剂作为预防 WT 小鼠和人源化小鼠骨质疏松症的手段的用途。 WT (C57BL/6) 小鼠、人脐带血干细胞植入 NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) 小鼠、人 MSC 植入 NSG 小鼠以及人脐带血干细胞和 MSC 植入 NSG 小鼠将进行 OVX 处理、治疗并通过 microCT 和骨进行评估 组织形态计量学。 Aim 1研究的一个新颖之处是使用从基因敲除小鼠中分离出的MSC异位形成的骨，然后将其植入WT小鼠体内，反之亦然，然后对骨组织形态参数进行分析——这可以确定MSC局部补体缺乏对骨形成和损失的作用，并探讨WT MSC时造血细胞中补体缺乏的影响 被植入补体敲除小鼠体内。 Aim 2 中使用 WT 小鼠和不同人源化小鼠进行的补体受体拮抗剂治疗实验最具临床相关性，并将探讨使用这些抑制剂治疗或预防人类骨质疏松症的潜力。这些研究将阐明补体信号减弱如何影响雌激素剥夺引起的骨质流失中的成骨细胞和破骨细胞分化。这些研究的长期目标是开发治疗或预防骨质疏松症的新疗法。 公共健康相关性：该项目将研究补体在骨质疏松症中调节骨转换的作用，这有可能将补体作为开发新的、有效的骨质疏松症疗法的新靶点。