Targeting sKlotho-FGF23 Interactions to Improve Pathological Phosphate Handling in CKD

靶向 sKlotho-FGF23 相互作用以改善 CKD 中的病理磷酸盐处理

基本信息

批准号：
10553159
负责人：
KENNETH E WHITE
金额：
$ 44.25万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-03-15 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10553159
关键词：
Acceleration Acute Affect Alleles Binding Proteins Biochemical Biological Process Biology Breeding CRISPR/Cas technology Cell surface Cells Cellular Membrane Chronic Chronic Kidney Failure Clinical Complex Data Data Set Defect Disease Dissection Etiology Event Exhibits Experimental Genetics FGFR1 gene Familial hypophosphatemic bone disease Familial tumoral calcinosis Fibroblast Growth Factor Receptors Fracture Functional disorder Genes Genetic Genetic Crosses Genetic Models Homeostasis Hormones Human Hypophosphatemia Impairment In Vitro Individual Injections Kidney Kidney Diseases Knockout Mice Lead Longevity LoxP-flanked allele MAP Kinase Gene Mediating Membrane Metabolism Minerals Modeling Molecular Mus Mutation Nephrons Onset of illness Organ Osteomalacia Pathogenesis Pathologic Pathway interactions Patients Peptide Hydrolases Phenotype Physiological Plasma Play Prevention Production Protein Isoforms Proximal Kidney Tubules Regulation Renal Mass Reporting Resistance Resolution Rickets Role Secondary to Serum Severities Signal Transduction Site Structure Syndrome Techniques Testing Time Tissues Validation Vascular calcification autosome beta-site APP cleaving enzyme 1 cell type design dietary extracellular fibroblast growth factor 23 functional loss improved in vivo in vivo Model inorganic phosphate insight loss of function mutation mortality new therapeutic target novel novel therapeutics nuclear factors of activated T-cells positional cloning prevent rare mendelian disorder receptor response sequencing platform single-cell RNA sequencing tissue injury wasting

项目摘要

Project Summary/Abstract: Investigating the molecular etiology of disorders caused by disturbed mineral metabolism has been instrumental in identifying new circulating regulators of phosphate homeostasis. We identified Fibroblast growth factor-23 (FGF23) in a positional cloning approach to isolate the gene responsible for autosomal dominant hypophosphatemic rickets (ADHR), characterized by hypophosphatemia secondary to renal phosphate wasting, rickets/osteomalacia, and fracture. The FGF23 co-receptor alpha-Klotho (KL), acting in a heteromeric complex with a canonical FGF receptor (FGFR), is required for normal phosphate metabolism. This is emphasized by the fact that KL loss of function mutations lead to end-organ FGF23 resistance, and cause the phenotypic reciprocal disorder to ADHR, hyperphosphatemic familial tumoral calcinosis (hfTC). In a similar manner, patients with chronic kidney disease (CKD) demonstrate impaired FGF23-responsiveness due to a loss of functional kidney mass and reduced Klotho expression, leading to increased serum phosphate concentrations and further increases in FGF23 production. KL is expressed as a membrane-bound protein (`mKL') that mediates FGF23-dependent signaling in target tissues, as well as a major circulating species that originates from the proteolytic cleavage of mKL within its juxta-extracellular membrane domain to derive a soluble form or `sKL'. Although the recent solving of the FGF23-sKL-FGFR1 triple crystal structure revealed insight into static sKL-FGF23 interactions, the complete scope of mKL versus sKL biological functions in the control of FGF23 and mineral metabolism remains unclear due to a lack of appropriate in vivo models. Our initial studies in mice with genetically reduced sKL expression showed aberrant FGF23 production in response to dietary phosphate challenges. Unlike global KL-KO mice, this model has the advantage of a lifespan that allows extended studies, providing new opportunities to gain critical insight into the regulation of FGF23 bioactivity in chronic conditions. Collectively, our results support mechanistic aims to identify specific sKL-FGF23 interactions in the control of phosphate metabolism, as well as to test sKL as a translational target in the treatment of human disorders. The central hypothesis to be tested in this proposal is: the sKL form of Klotho is required for normal FGF23-mediated phosphate handling and is protective during renal disease. We expect our studies using dovetailed, cutting-edge in vivo and in vitro techniques to provide novel, translational insight into the basic biology of phosphate metabolism, as well as into both rare and common syndromes of altered Klotho and FGF23 expression.

项目摘要/摘要：调查矿物质疾病引起的疾病的分子病因代谢一直在识别磷酸盐稳态的新循环调节剂中发挥了作用。我们在位置克隆方法中鉴定出的成纤维细胞生长因子23（FGF23）以分离基因负责常染色体显性次磷酸脑rik（ADHR），其特征是继发于肾磷酸盐浪费，瑞克/骨乳核酸和骨折的低磷酸血症。 FGF23 联合受体α-klotho（KL），作用于具有规范FGF受体（FGFR）的异性络合物，为正常磷酸代谢所必需的。 KL的功能丧失可以强调这一点突变导致末端FGF23耐药性，并导致表型相互障碍adhr，高磷酸家族性肿瘤钙化（HFTC）。以类似的方式，患有慢性肾脏的患者疾病（CKD）表明，由于功能性肾脏肿块的损失，FGF23的反应受损 klotho表达降低，导致血清磷酸盐浓度升高，进一步增加 FGF23生产。 KL表示为膜结合的蛋白（“ MKL”），介导FGF23依赖性靶组织中的信号传导以及起源于蛋白水解的主要循环系统 MKL在其近距离细胞膜结构域中的切割，以得出可溶性形式或“ SKL”。虽然 FGF23-SKL-FGFR1三重晶体结构的最新解决方案揭示了对静态SKL-FGF23的洞察力相互作用，在FGF23和矿物的控制中，MKL与SKL生物学功能的完整范围由于缺乏合适的体内模型，代谢仍然不清楚。我们在小鼠中的最初研究基因降低的SKL表达显示出对饮食磷酸盐的异常产生挑战。与全球KL-KO小鼠不同，该模型具有寿命的优势，该寿命允许扩展研究，提供了新的机会，以获得对慢性FGF23生物活性调节的关键见解状况。总的来说，我们的结果支持机理旨在确定特定的SKL-FGF23相互作用控制磷酸盐代谢，以及测试SKL作为治疗的转化目标人类疾病。在此提案中要检验的中心假设是：需要克洛索的SKL形式对于正常的FGF23介导的磷酸盐处理，在肾脏疾病中具有保护性。我们期望我们的使用燕尾尾尾，尖端的体内和体外技术的研究来提供新颖的转化见解进入磷酸盐代谢的基本生物学，以及改变的稀有和常见综合症 Klotho和FGF23表达。