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.

项目摘要/摘要 我实验室的长期目标是对细胞内的全面了解 代谢途径影响骨骼健康。在此范围内，当前的项目旨在探索骨 间歇性甲状旁腺激素（IPTH）的合成代谢作用通过调节脂质代谢对细胞内的细胞内的调节 骨骼利基。骨质疏松症和骨质骨减少症是晚期发作的疾病，影响了惊人的5400万 美国的人 。 除了经济燃烧外，与骨质疏松相关的裂缝还经常导致多个 合并症会大大降低寿命。而合成代谢剂会增加骨形成 PTH或PTH相关蛋白（PTHRP）有助于骨质疏松症的治疗，患者仍然经历 不良副作用。因此，必须继续开发精致的治疗选择。像这样， 该项目提出了双重的免费机制，通过该机制，PTH信号上调了骨骼的脂解 骨髓脂肪细胞（BMADIPO），将脂质物种释放到骨骼生态位，同时还增强了脂肪酸 成骨细胞中的氧化。鉴于Bmadipo与成骨细胞的亲密关系，它是有理由的 治疗作用于两种BMADIPO以释放脂质物种，同时“启动”成骨细胞以利用这些脂质 作为能够支持骨形成能量的过程的机制。因此，我们的 总体假设是PTH的骨合成代谢作用涉及BMADIPO和 成骨细胞中增强的脂肪酸氧化。我们将以两个具体的目的来检验这一假设。第一个目标 （SA1）将确定PTH刺激的BMADIPO脂解的能力支持PTH诱导的骨形成， 体内和体外。这将使用由Co-I开发的新鼠标模型来完成 特别抑制bmadipo中的脂解。然后，这些小鼠将进行卵巢切除（OVX）或假手术 并通过PTH或车辆控制进行处理。骨骼和代谢参数将在结束时进行评估 研究。除了该实验外，PTH治疗后从BMADIPO释放的脂质物种将是 使用液相色谱 - 质谱法（LC-MS）进行表征。第二个目标（SA2）将定义 PTH可以通过调节细胞生物能来改变成骨细胞脂质代谢的能力。追踪13C18 Oleic 酸将使用LC-MS在成骨细胞中PTH处理期间确定脂肪酸代谢命运。 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 PTH使用Seahorse XFE96技术。最后，将使用反向 - 阶段高性能液相色谱（RP-HPLC）确定腺苷一磷酸（AMP），， 腺苷二磷酸（ADP）和在对照条件下以及PTH刺激期间的ATP通量。总之， 该项目的目的是增强我们对PTH通过 脂质代谢的调节。预计该项目将具有很大的健康相关影响 确定热勘探的新领域，这些领域对于改善骨质疏松症的治疗至关重要。