Skeletal FGF23 production mediated by GPCR/Gq/PKC signaling

GPCR/Gq/PKC 信号传导介导的骨骼 FGF23 产生

• 批准号: 10376665
• 负责人: MURAT BASTEPE
• 金额: $ 38.99万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10376665
• 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 alpha q Protein; G-Protein-Coupled Receptors; GTP-Binding Proteins; Gene Expression Profiling; Generations; Genomics; Goals; Heart; Hormones; Impairment; Inherited; Injections; Ions; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; Knowledge; Lysophosphatidic Acid Receptors; MAP Kinase Gene; MAPK3 gene; Mediating; Mediator of activation protein; 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; base; bone; bone health; 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

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.

摘要 成纤维细胞生长因子23（Fibroblast growth factor-23，FGF 23）是一种骨源性磷酸尿激素，在调节成纤维细胞生长中起关键作用 血清磷酸盐水平和维生素D代谢。FGF 23作用失调是发病机制的基础 与矿物质离子代谢异常有关的几种骨骼疾病。肾脏中的血清FGF 23水平也升高 失败和升高的FGF 23水平极大地促进了与慢性骨质疏松症相关的矿物质和骨骼疾病。 肾病需要有效的策略来控制骨骼FGF 23的产生，以改善 这些疾病的临床管理。然而，控制FGF 23产生的机制仍然很差， 阻碍了这一目标的实现。已经描述了几种FGF 23刺激剂，但是 其作用的分子决定因素还不完全清楚。细胞内信号通路是 不知道他们是如何互相影响的。我们现在已经确认 溶血磷脂酸（LPA）作为一种新的FGF 23合成刺激剂，并发现它通过其G 蛋白偶联受体LPAR 1。我们还发现，在小鼠中，LPAR 1的消融阻断了FGF 23的升高， 急性肾损伤模型。我们的初步实验也有力地表明，LPA的作用， 涉及Gq/11/PKC信号通路通过依赖于MAPK-ERK 1/2信号传导的机制起作用。 此外，我们的研究结果有力地表明LPA-Gq/11/PKC途径对FGF 23的产生至关重要。 由1，25-二羟维生素D（1，25 D）诱导。在这个提议中，我们将研究FGF 23的这种新的范式， 骨细胞合成。目的1探讨骨细胞特异性Gq/11/PKC信号通路在LPA诱导的骨细胞凋亡中的作用。 FGF 23的产生，检查该途径与MAPK-ERK 1/2信号传导的相互作用，并确定 它是否在膳食磷酸盐诱导的FGF 23水平升高中起作用。对于这些研究，我们将 使用Gq/11α在骨细胞中条件性消融的小鼠（Gq/11α Dmp 1 KO小鼠，我们实验室可获得）， 以及适用于研究FGF 23合成的骨细胞/成骨细胞样细胞系。目标2将阐明 在FGF 23产生中1，25 D和LPA-Gq/11/PKC信号传导的作用之间的串扰，使用两种细胞- 基于分析和小鼠模型（Gq/11α Dmp 1 KO和维生素D受体敲除小鼠，也可在我们的 实验室）。目的3将研究Gq/11/PKC信号传导在过度产生FGF 23的病理条件中的作用， 包括X连锁低磷血症性佝偻病（XLH）和肾衰竭。我们将采用Hyp小鼠（一种建立的 XLH模型），其将与Gq/11α Dmp 1 KO小鼠杂交。用于研究肾衰竭诱导的FGF 23 我们将使用由富含腺嘌呤的饮食诱导的慢性肾病模型。我们的研究将 阐明LPA-Gq/11/PKC通路作为骨细胞中FGF 23产生的刺激物的作用，并鉴定 其与FGF 23合成的其他重要系统调节剂的细胞作用的关系。我们 因此，预测的结果将显著增加控制FGF 23合成的机制的知识 并且可能产生用于由FGF 23作用失调引起或影响的疾病的新药靶点。