Skeletal FGF23 production mediated by GPCR/Gq/PKC signaling

GPCR/Gq/PKC 信号传导介导的骨骼 FGF23 产生

基本信息

批准号：
10598571
负责人：
MURAT BASTEPE
金额：
$ 40.84万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10598571
关键词：
Ablation Acute Renal Failure with Renal Papillary Necrosis Adenine Affect Biological Assay Blood Bone Development Bone Diseases Cardiovascular system Cell Line Cells Chronic Kidney Failure Clinical Management Coupled Diet Dihydroxycholecalciferols Disease Disease Management FGFR1 gene Familial hypophosphatemic bone disease Feedback Functional disorder G-Protein-Coupled Receptors GTP-Binding Proteins Gene Expression Profiling Generations Genomics Goals Heart Hormone secretion Hormones Impairment Inherited Injections Ions Kidney Kidney Diseases Kidney Failure Knockout Mice Knowledge Lysophosphatidic Acid Receptors MAP Kinase Gene MAPK3 gene Mediating Mediator Metabolism Minerals Modeling Molecular Mus Organ Osteoblasts Osteocytes Outcome Pathogenesis Pathologic Pathway interactions Patients Phenotype Plasma Play Process Production Protein Kinase C Regulation Role Serum Side Signal Pathway Signal Transduction Testing Tetradecanoylphorbol Acetate Vitamin D Vitamin D3 Receptor Wild Type Mouse bone bone health comparison control dietary effective therapy experimental study fibroblast growth factor 23 human disease improved inorganic phosphate lysophosphatidic acid mortality mouse model mutant new therapeutic target novel promoter receptor response skeletal skeletal disorder

项目摘要

Abstract Fibroblast growth factor-23 (FGF23), a bone-derived phosphaturic hormone, plays a key role in the regulation of serum phosphate levels and vitamin D metabolism. Dysregulated FGF23 actions underlie the pathogenesis of several skeletal diseases with abnormal mineral ion metabolism. Serum FGF23 levels also rise in kidney failure, and elevated FGF23 levels contribute greatly to the mineral and bone disorder associated with chronic kidney disease. Effective strategies for controlling skeletal FGF23 production are needed in order to improve the clinical management of these disorders. However, mechanisms governing FGF23 production remain poorly defined, impeding progress toward this goal. Several FGF23 stimulators have been described, but the molecular determinants of their actions are incompletely understood. The intracellular signaling pathways are not elucidated, and it remains unknown how those interact with one another. We have now identified lysophosphatidic acid (LPA) as a novel stimulator of FGF23 synthesis and found that it acts through its G protein-coupled receptor LPAR1. We also showed that ablation of LPAR1 blocks the rise of FGF23 in a mouse model of acute kidney injury. Our preliminary experiments also strongly suggested that the action of LPA involves Gq/11/PKC signaling pathway operating via a mechanism that depends on MAPK-ERK1/2 signaling. Moreover, our results strongly suggested that the LPA-Gq/11/PKC pathway is critical for FGF23 production induced by 1,25-dihydroxyvitamin D (1,25D). In this proposal, we will investigate this novel paradigm of FGF23 synthesis in osteocytes. Aim 1 will determine the role of osteocyte-specific Gq/11/PKC signaling in LPA-induced FGF23 production, examine the interaction of this pathway with MAPK-ERK1/2 signaling, and determine whether it plays a role in the dietary phosphate-induced elevation of FGF23 levels. For those studies, we will employ mice in which Gq/11α are ablated conditionally in osteocytes (Gq/11αDmp1KO mice, available in our lab), as well as osteocyte/osteoblast-like cell lines suitable for studying FGF23 synthesis. Aim 2 will elucidate the cross-talk between the action of 1,25D and LPA-Gq/11/PKC signaling in FGF23 production, using both cell- based assays and mouse models (Gq/11αDmp1KO and vitamin D receptor knockout mice, also available in our lab). Aim 3 will examine the role of Gq/11/PKC signaling in pathological conditions of excess FGF23 production, including X-linked hypophosphatemic rickets (XLH) and renal failure. We will employ Hyp mice (an established model of XLH), which will be crossed with Gq/11αDmp1KO mice. For studying renal failure-induced FGF23 overproduction, we will use a model of chronic kidney disease induced by adenine-rich diet. Our studies will elucidate the role of the LPA-Gq/11/PKC pathway as a stimulator of FGF23 production in osteocytes and identify its relationship with the cellular actions of other important systemic regulators of FGF23 synthesis. Our predicted results will thus markedly increase the knowledge of the mechanisms controlling FGF23 synthesis and are likely to yield new drug targets for diseases caused or affected by dysregulated FGF23 actions.

抽象的成纤维细胞生长因子 23 (FGF23) 是一种骨源性磷酸激素，在调节中发挥关键作用血清磷酸盐水平和维生素 D 代谢失调是发病机制的基础。一些骨骼疾病的矿物质离子代谢异常也会导致肾脏中血清 FGF23 水平升高。衰竭和 FGF23 水平升高极大地导致与慢性疾病相关的矿物质和骨骼疾病为了改善肾脏疾病，需要有效的策略来控制骨骼 FGF23 的产生。然而，控制 FGF23 产生的机制仍然很差。已描述了几种 FGF23 刺激剂，但阻碍了实现这一目标的进展。其作用的分子决定因素尚不完全清楚。尚未阐明，而且我们现在已经确定了它们如何相互作用。溶血磷脂酸 (LPA) 作为 FGF23 合成的新型刺激剂，并发现它通过其 G 发挥作用我们还表明，LPAR1 的消除会阻止小鼠体内 FGF23 的升高。我们的初步实验也强烈表明 LPA 的作用。涉及 Gq/11/PKC 信号通路通过依赖于 MAPK-ERK1/2 信号传导的机制进行操作。此外，我们的结果强烈表明 LPA-Gq/11/PKC 途径对于 FGF23 的产生至关重要由 1,25-二羟基维生素 D (1,25D) 诱导的在本提案中，我们将研究 FGF23 的这种新范例。目标 1 将确定骨细胞特异性 Gq/11/PKC 信号在 LPA 诱导中的作用。 FGF23 的产生，检查该途径与 MAPK-ERK1/2 信号传导的相互作用，并确定对于这些研究，我们将确定它是否在膳食磷酸盐诱导的 FGF23 水平升高中发挥作用。使用骨细胞中 Gq/11α 有条件消融的小鼠（Gq/11αDmp1KO 小鼠，我们实验室提供），如以及适合研究 FGF23 合成的骨细胞/成骨细胞样细胞系将阐明 FGF23 合成。 FGF23 生产中 1,25D 和 LPA-Gq/11/PKC 信号传导作用之间的串扰，使用细胞基于检测和小鼠模型（Gq/11αDmp1KO 和维生素 D 受体敲除小鼠，也可在我们的目标 3 将检查 Gq/11/PKC 信号在 FGF23 过量产生的病理条件下的作用，包括 X 连锁低磷血症性佝偻病 (XLH) 和肾功能衰竭。我们将使用 Hyp 小鼠（一种已确定的小鼠）。 XLH 模型），该模型将与 Gq/11αDmp1KO 小鼠杂交，用于研究肾衰竭诱导的 FGF23。生产过剩，我们将使用富含腺嘌呤饮食诱发的慢性肾病模型。阐明 LPA-Gq/11/PKC 通路作为骨细胞中 FGF23 生成刺激剂的作用，并确定它与 FGF23 合成的其他重要系统调节因子的细胞作用的关系。因此，预测结果将显着增加对控制 FGF23 合成机制的了解并有可能针对 FGF23 作用失调引起或影响的疾病产生新的药物靶点。