Parathyroid hormone (PTH) modulates lipid metabolism in the skeletal niche

甲状旁腺激素 (PTH) 调节骨骼生态位中的脂质代谢

• 批准号: 10093413
• 负责人: Elizabeth Rendina-Ruedy
• 金额: $ 44.03万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-30 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10093413
• 关键词: Adenosine Diphosphate; Adenosine Triphosphate; Adipocytes; Adipose tissue; Adult; Adverse event; Affect; Age; Anabolic Agents; Animal Model; Area; Bioenergetics; Bone Marrow; Buffers; Calcium; Caloric Restriction; Cells; Charge; Collagen Type I; Data; Dependence; Development; FDA approved; Fatty Acids; Financial Hardship; Forteo; Fracture; Genus Hippocampus; Goals; Health; High Pressure Liquid Chromatography; Hormone use; In Vitro; Laboratories; Late-Onset Disorder; Lead; Lipids; Lipolysis; Longevity; Measures; Metabolic; Metabolic Pathway; Metabolism; Mitochondria; Molecular; Monitor; Mus; Nonesterified Fatty Acids; Oleic Acids; Operative Surgical Procedures; Osteoblasts; Osteogenesis; Osteopenia; Osteoporosis; Outcome; Outcome Study; Ovariectomy; Oxidative Phosphorylation; PTH gene; Patients; Pharmaceutical Preparations; Phase; Population; Process; Production; Proteins; Public Health; Regulation; Respiration; Stromal Cells; Technology; Testing; Therapeutic; Up-Regulation; X-Ray Computed Tomography; adenosine monophosphate-adenosine; bone; bone health; bone mass; combat; comorbidity; design; experimental study; fatty acid oxidation; flexibility; hormonal signals; improved; in vivo; insight; lipid metabolism; liquid chromatography mass spectrometry; model design; mouse model; novel; osteoporosis with pathological fracture; oxidation; parathyroid hormone-related protein; primary outcome; response; side effect; skeletal; spine bone structure; tibia

PROJECT SUMMARY/ ABSTRACT The long-term goal of my laboratory is to develop a comprehensive understanding of how intracellular metabolic pathways impact bone health. Within this scope the current project aims to explore the osteo- anabolic effects of intermittent parathyroid hormone (iPTH) via its modulation of lipid metabolism on cells within the skeletal niche. Osteoporosis and osteopenia are late-onset diseases affecting a staggering 54 million people in the U.S . In addition to the financial burden, osteoporosis-related fractures often lead to multiple comorbidities which significantly reduce longevity. While anabolic agents that increase bone formation such as PTH or PTH related protein’s (PTHrP) have aided in the management of osteoporosis, patients still experience adverse side-effects. Therefore, continued development of refined therapeutic options is necessary. As such, this project presents dual, complimentary mechanisms whereby PTH signaling up-regulates lipolysis in bone marrow adipocytes (BMAdipo), releasing lipid species into the skeletal niche, while also enhancing fatty acid oxidation in osteoblasts. Given the intimate proximity of BMAdipo to osteoblasts, it stands to reason that PTH treatment acts on both BMAdipo to liberate lipid species while also ‘priming’ the osteoblast to utilize these lipids as a mechanism capable of supporting the energy demanding process of bone formation. Therefore, our overarching hypothesis is that PTH’s bone anabolic actions involve stimulation of lipolysis in BMAdipo and enhanced fatty acid oxidation in osteoblasts. We will test this hypothesis in two specific aims. The first aim (SA1) will determine the ability of PTH-stimulated BMAdipo lipolysis to support PTH-induced bone formation, both in vivo and in vitro. This will be accomplished using a new mouse model, developed by the Co-I, designed to specifically inhibit lipolysis in BMAdipo. These mice will then be ovariectomized (OVX) or sham-operated on and be treated with PTH or vehicle control. Skeletal and metabolic parameters will be assessed at the end of the study. In addition to this experiment, lipid species released from BMAdipo upon PTH treatment will be characterized using liquid chromatography-mass spectrometry (LC-MS). The second aim (SA2) will define PTH’s ability to alter osteoblast lipid metabolism via modulation of cellular bioenergetics. Tracing of 13C18 oleic acid will be performed using LC-MS to determine fatty acid metabolic fate during PTH treatment in osteoblasts. Additionally, osteoblast mitochondrial oxidative phosphorylation substrate dependency will be measured during PTH using Seahorse XFe96 technology. Finally, osteoblast bioenergetics will be monitored using reversed- phase high-performance liquid chromatography (RP-HPLC) to determine adenosine monophosphate (AMP), adenosine diphosphate (ADP), and ATP flux under control conditions and during PTH stimulation. In summary, the goal of this project is to enhance our understanding of PTH’s ability to promote bone formation via the modulation of lipid metabolism. This project is expected to have substantial health-related influence as it will identify new areas for therapeutic exploration that are crucial to improve the management of osteoporosis.

项目概要/摘要 我实验室的长期目标是全面了解细胞内如何 在此范围内，当前项目旨在探索骨健康的代谢途径。 间歇性甲状旁腺激素（iPTH）通过调节细胞内的脂质代谢来发挥合成代谢作用 骨质疏松症和骨质减少是晚发性疾病，影响着 5400 万人。 在美国的人 。 除了经济负担外，骨质疏松症相关的骨折通常会导致多种症状。 显着缩短寿命的合并症，而促进骨形成的合成代谢药物，例如 PTH 或 PTH 相关蛋白 (PTHrP) 有助于骨质疏松症的治疗，但患者仍然会经历 因此，有必要继续开发精细的治疗方案。 该项目提出了双重互补机制，PTH 信号传导上调骨中的脂肪分解 骨髓脂肪细胞 (BMAdipo)，将脂质物质释放到骨骼生态位中，同时还增强脂肪酸 鉴于 BMAdipo 与成骨细胞非常接近，PTH 是理所当然的。 治疗作用于 BMAdipo 释放脂质物质，同时“启动”成骨细胞利用这些脂质 作为一种能够支持骨形成过程所需能量的机制。 总体假设是 PTH 的骨合成代谢作用涉及刺激 BMAdipo 和 我们将在两个具体目标中检验这一假设。 (SA1) 将确定 PTH 刺激的 BMAdipo 脂肪分解支持 PTH 诱导的骨形成的能力， 这将通过 Co-I 开发并设计的新小鼠模型来完成。 特异性抑制 BMAdipo 中的脂肪分解，然后对这些小鼠进行卵巢切除 (OVX) 或假手术。 并接受 PTH 或媒介物控制治疗，将在治疗结束时评估骨骼和代谢参数。 除了本研究之外，PTH 处理后 BMAdipo 释放的脂质物质也将被释放。 使用液相色谱-质谱 (LC-MS) 进行表征 第二个目标 (SA2) 将定义。 PTH 通过调节细胞生物能量来改变成骨细胞脂质代谢的能力。 将使用 LC-MS 进行酸分析，以确定 PTH 治疗期间成骨细胞中脂肪酸的代谢命运。 此外，将在期间测量成骨细胞线粒体氧化磷酸化底物依赖性 使用 Seahorse XFe96 技术的 PTH 最后，将使用反向监测成骨细胞生物能。 相高效液相色谱 (RP-HPLC) 测定单磷酸腺苷 (AMP)， 总之，在控制条件下和 PTH 刺激期间，二磷酸腺苷 (ADP) 和 ATP 通量。 该项目的目标是增强我们对 PTH 通过以下方式促进骨形成的能力的理解： 脂质代谢的调节预计该项目将对健康产生重大影响。 确定对于改善骨质疏松症治疗至关重要的治疗探索新领域。