SIK Activators to Treat PTH Pathway Bone Diseases

SIK 激活剂治疗 PTH 通路骨疾病

基本信息

批准号：
10811083
负责人：
Carole Anne Le Henaff
金额：
$ 38.96万
依托单位：
NEW YORK UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-09-19 至 2025-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10811083
关键词：
Adult Area Autopsy Binding Biochemical Biomechanics Bone Diseases Calvaria Cells Collagen Continuous Infusion Cyclic AMP Cyclic AMP-Dependent Protein Kinases Cytoplasm Data Dependence Development Disease Dose Dysplasia Enzymes Female GTP-Binding Protein alpha Subunits, Gs Gene Expression Genes Genetic Diseases Genetic Transcription Goals HDAC4 gene HDAC5 gene Histone Deacetylase Hyperactivity Hyperparathyroidism Injections McCune-Albright Syndrome Measures Mediating Messenger RNA Metaphyseal chondrodysplasia Modeling Mus Nuclear Translocation Operative Surgical Procedures Oral Osteoblasts Osteoclasts Other Genetics PTH gene Parathyroid Hormone Receptor Pathway interactions Patients Phenotype Phosphorylation Phosphorylation Inhibition Phosphotransferases Proteins Regulation Research Screening procedure Signal Pathway Skeleton Tail Tamoxifen Testing Time Transcription Coactivator Wild Type Mouse Work bone bone turnover cortical bone cranium drug discovery experimental study in vivo knock-down long bone mouse model palliative parathyroid hormone (1-34)preclinical study response salt-inducible kinase skeletal disorder small molecule spine bone structure substantia spongiosa

项目摘要

An overactive Parathyroid Hormone Receptor 1 (PTHR1) and its downstream signaling pathway (Gsα) are involved in several bone diseases including hyperparathyroidism, Jansen’s metaphyseal chondrodysplasia (due to a constitutively active PTHR1) or Fibrous Dysplasia-McCune-Albright Syndrome (due to a constitutively active Gsα) which, in the case of the genetic diseases, can cause major developmental and lifelong problems with their skeletons. In all three situations, the only therapies available are surgical or palliative. Protein Kinase A (PKA) is an enzyme whose activity is dependent on the activity of Gsα and cellular levels of cAMP. It is regulated by PTH binding to PTHR1 in osteoblasts. We have generated an inducible, osteoblast-specific mouse model of hyperactive PKA by collagen 1-directed deletion of the regulatory subunit, Prkar1a, and found a high bone turnover phenotype in skulls, long bones, vertebrae and caudal bones of the tail that mimics the PTHR1 diseases. We and others have shown that PTH action on the osteoblast through PKA controls gene expression, in part, through inhibition by phosphorylation of salt-inducible kinases (SIKs). These kinases tonically phosphorylate cAMP-regulated transcriptional coactivators (CRTC1, 2 and 3) and histone deacetylases 4/5 (HDAC4/5), sequestering them in the cytoplasm. Upon PTH action, PKA-mediated SIK inhibition causes CRTC2 and HDAC4/5 phosphorylation levels to decrease with subsequent nuclear translocation of CRTC2/3 and HDAC4/5 which mediates transcription of the osteoclastogenic gene, Rankl, regulation of Mmp13 and suppression of Sost transcription. SIK inhibition, deletion or knockdown mimics the effects of PTH. We have recently tested several agents for possible activation of the SIKs and resultant inhibition of PTH-induced Rankl transcription in differentiating mouse calvarial osteoblasts and found a small molecule, 9117014, as a “putative” SIK activator, to fit these goals. From these data of cells in culture and preliminary data in vivo, we have developed the hypothesis that small molecule activators of SIKs will reverse the unwanted effects of the PTH signaling pathway in bone. Consequently, the specific aims of this resubmitted R21 application are to 1) determine if activation of SIKs by a small molecule will inhibit PTH- regulated gene expression in osteoblasts, by a. performing dose responses on PTH-stimulation of Rankl, b. knocking down SIK2/3, c. testing the effects on other PTH-regulated genes, 2) assess if a small molecule activator of SIKs will inhibit a high bone turnover phenotype in mice, by a. injecting a developmental model of high bone turnover, b. injecting an adult model of high bone turnover, c. injecting an adult model of hyperparathyroidism, and conducting complete bone analyses. In so doing, the results would be of high impact and may lead to further preclinical studies that could form the basis for the first disease-modifying oral treatments for patients with hyperparathyroidism, Jansen’s metaphyseal chondrodysplasia or Fibrous Dysplasia-McCune-Albright Syndrome.

过度活跃的甲状旁腺激素受体 1 (PTHR1) 及其下游信号通路 (Gsα) 涉及多种骨骼疾病，包括甲状旁腺功能亢进症、詹森干骺端软骨发育不良（由于组成性活跃的 PTHR1）或纤维性发育不良-麦库恩-奥尔布赖特综合征（由于组成性活跃的 PTHR1）活性 Gsα），在遗传疾病的情况下，可能会导致严重的发育和终生问题在这三种情况下，唯一可用的疗法是手术或姑息疗法。 A (PKA) 是一种酶，其活性取决于 Gsα 的活性和细胞内 cAMP 的水平。受成骨细胞中 PTH 与 PTHR1 结合的调节我们已经产生了一种可诱导的、成骨细胞特异性的。通过胶原蛋白 1 定向删除调节亚基 Prkar1a 建立了过度活跃的 PKA 小鼠模型，并发现头骨、长骨、椎骨和尾骨的高周转骨表型模仿了我们和其他人已经证明 PTH 通过 PKA 控制基因对成骨细胞起作用。部分地通过盐诱导激酶 (SIK) 的磷酸化来抑制这些激酶的表达。强磷酸化 cAMP 调节的转录共激活因子（CRTC1、2 和 3）和组蛋白脱乙酰酶 4/5 (HDAC4/5)，将其隔离在细胞质中 PTH 作用，PKA 介导的 SIK。抑制会导致 CRTC2 和 HDAC4/5 磷酸化水平随着随后的核 CRTC2/3 和 HDAC4/5 的易位介导破骨细胞生成基因 Rankl 的转录， Mmp13 的调节和 SIK 转录的抑制、缺失或敲低模仿了这一过程。我们最近测试了几种可能激活 SIK 的药物及其结果。在分化小鼠颅骨成骨细胞中抑制 PTH 诱导的 Rankl 转录，并发现一个小分子 9117014 作为“推定的”SIK 激活剂，可以根据培养和细胞的这些数据来实现这些目标。根据体内初步数据，我们提出了 SIK 的小分子激活剂会逆转的假设测试 PTH 信号通路的不良影响，其具体目的。重新提交的 R21 申请旨在 1) 确定小分子激活 SIK 是否会抑制 PTH- 通过对 Rankl 的 PTH 刺激进行剂量反应来调节成骨细胞中的基因表达，b．敲低 SIK2/3，c. 测试对其他 PTH 调节基因的影响，2) 评估小分子是否有效 SIK 激活剂将通过注射发育模型来抑制小鼠的高骨转换表型。高骨转换，b.注射高骨转换的成人模型，c. 甲状旁腺功能亢进症，并进行完整的骨骼分析，这样做，结果会很高。影响，并可能导致进一步的临床前研究，这些研究可能构成第一个缓解疾病的口服药物的基础甲状旁腺功能亢进症、詹森干骺端软骨发育不良或纤维性软骨发育不良患者的治疗发育不良-麦库恩-奥尔布赖特综合征。