Development of Targeted Drugs for Osteoporosis

骨质疏松症靶向药物的开发

• 批准号: 9894758
• 负责人: XU FENG
• 金额: $ 27.73万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-15 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9894758
• 关键词: Address; Affect; Albers-Schonberg disease; Antibodies; Binding; Biological Assay; Biological Products; Biology; Bone Resorption; Bone Resorption Inhibition; Bone necrosis; Cell Differentiation process; Cells; Cytoplasmic Tail; Data; Deterioration; Development; Disease; Drug Kinetics; Drug Targeting; Exploratory/Developmental Grant; Failure; Feasibility Studies; Femoral Fractures; Foundations; Future; Genes; Goals; Immune; Immune system; Immunologist; In Vitro; Infection; Injections; Intravenous; Jaw; Knock-in Mouse; Ligands; MAP Kinase Gene; MAPK Signaling Pathway Pathway; Macrophage Colony-Stimulating Factor; Macrophage Colony-Stimulating Factor Receptor; Mediating; Methods; Mus; Mutation; Oral; Osteoclasts; Osteogenesis; Osteoporosis; Outcome; Ovariectomy; Pathway interactions; Pharmaceutical Chemistry; Pharmaceutical Preparations; Postmenopausal Osteoporosis; Property; Public Health; Publishing; Research; Research Project Grants; Risk; Role; Route; Safety; Signal Pathway; Skeleton; Study models; System; TRANCE protein; Testing; Therapeutic; Thymic epithelial cell; Treatment Efficacy; Work; analog; base; bone; bone fragility; bone loss; bone mass; cost; design; drug discovery; experience; fracture risk; high throughput screening; immune system function; improved; in vivo; infection risk; intraperitoneal; macrophage; monocyte; mouse model; new therapeutic target; novel; prevent; programmed cell death protein 1; receptor; side effect; small molecule; subcutaneous; success; therapeutic target; therapy outcome

Project Summary Osteoporosis is a common disease characterized by low bone mass and microarchitectural deterioration of the skeleton, resulting in bone fragility and increased risks for fractures. Osteoporosis is caused by an imbalance between bone resorption and bone formation in favor of bone resorption. Thus, effective inhibition of bone resorption has long been recognized as an important therapeutic strategy for osteoporosis. Osteoclasts, the bone resorbing cell, differentiate from cells of the monocyte/macrophage lineage upon stimulation by M-CSF and RANKL. RANKL exerts these diverse functions by binding and activating its receptor RANK. Mice lacking the gene for either RANKL or RANK develop osteopetrosis due to complete failure to form osteoclast, indicating that the RANKL/RANK system is essential for osteoclast formation. Thus, RANKL was recognized as an attractive antiresorptive drug target for osteoporosis shortly after its discovery and Amgen subsequently developed a humanized anti-RANKL antibody (denosumab) for treating postmenopausal osteoporosis. However, denosumab causes several side effects such as osteonecrosis of the jaw (ONJ), increased risk of serious infections and atypical femur fractures. In particular, ONJ and increased infection risks are likely due to the suppressing effect of denosumab on the immune system since RANKL regulates immune cell development, function and survival. Also, as a biological agent, the cost of denosumab is high and the method of delivery (injection) is not ideal. Thus, a better targeting strategy would be to use small molecules to target RANK signaling pathways that are involved in osteoclast formation but not in the immune system function. We previously identified two motifs in the RANK cytoplasmic domain that regulate osteoclast formation in vitro. To assess the role of the two RANK motifs in osteoclast formation in vivo, we have generated knockin (KI) mice bearing inactivating mutations in the two RANK motifs. Osteoclast formation is dramatically reduced in the KI mice, confirming the role of these two motifs in osteoclast formation in vivo. Importantly, inactivation of these two motifs does not affect the ability of RANK to activate the signaling pathways (NF-κB and MAPK) known to mediate immune cell development and function. Hence, we hypothesize that specifically targeting these two RANK motifs has the potential to serve as effective and selective therapeutic targets for osteoporosis. Our ultimate goal is to develop efficacious and safe small molecule drugs targeting the two RANK motifs for osteoporosis. To this end, we have developed cell-based assays for identifying compounds targeting the two RANK motifs. High throughput screens of 200,000 compounds with the cell-based assay systems followed by counter screen assays have identified several compounds that potently inhibited osteoclast formation without affecting the activation of NF-κB and MAPK pathways in vitro. This proposal seeks to carry out important proof- of-concept studies to assess the conceptual and technical feasibility of this novel therapeutic targeting strategy.

项目摘要 骨质疏松症是一种常见疾病，其特征是骨骼质量低和微构造的定义 骨骼，导致骨骼脆弱性和裂缝风险增加。骨质疏松是由失衡引起的 在骨骼分辨率和骨骼形成之间，有利于骨骼分辨率。那有效抑制骨头 长期以来，分辨率被认为是骨质疏松症的重要治疗策略。破骨细胞， M-CSF刺激后，骨吸收细胞与单核细胞/巨噬细胞谱系的细胞区分开 和Rankl。 RANKL通过结合和激活其受体等级来发挥这些潜水功能。小鼠缺乏 RANKL或等级的基因由于完全未能形成破骨细胞而出现骨质倍率， 表明RANKL/等级系统对于破骨细胞的形成至关重要。那，兰克被认为 发现后不久，骨质疏松症的有吸引力的抗吸毒靶标和Amgen随后 开发了一种人源化的抗碱基抗体（Denosumab），用于治疗绝经后骨质疏松症。 但是，Denosumab引起多种副作用，例如颌骨的骨坏死（ONJ），增加了 严重的感染和非典型股骨骨折。特别是，ONJ和感染风险增加可能是由于 Denosumab对免疫系统的抑制作用，因为RANKL调节免疫细胞 发展，功能和生存。同样，作为生物剂，地诺单抗的成本很高，方法 交付（注射）不是理想的。这是一个更好的定位策略是使用小分子靶向 与破骨细胞形成有关的等级信号通路，但不参与免疫系统功能。我们 先前鉴定出在体外调节破骨细胞形成的等级细胞质结构域中的两个基序。到 评估两个等级基序在体内破骨细胞形成中的作用，我们已经产生了敲击蛋白（Ki）小鼠 在两个等级基序中丧失突变。在Ki中，破骨细胞的形成大大减少 小鼠证实了这两个基序在体内破骨细胞形成中的作用。重要的是，这些失活 两个基序不影响等级激活信号通路（NF-κB和MAPK）的能力 介导免疫细胞的发育和功能。因此，我们假设专门针对这两个 等级基序有可能作为骨质疏松症的有效和选择性治疗靶标。我们的 最终目标是开发针对两个等级基序的高效且安全的小分子药物 骨质疏松症。为此，我们开发了基于细胞的测定方法，用于识别针对两者的化合物 等级图案。具有基于细胞的测定系统的200,000种化合物的高吞吐量屏幕，然后是 计数器屏幕测定已经确定了几种可能抑制破骨细胞形成的化合物 在体外影响NF-κB和MAPK途径的激活。该提案试图进行重要的证据 - 概念研究以评估这种新型治疗靶向策略的概念和技术可行性。