SIK Activators to Treat PTH Pathway Bone Diseases

SIK 激活剂治疗 PTH 通路骨疾病

• 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
• 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

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.

一种过度活跃的甲状旁腺激素受体1（PTHR 1）及其下游信号通路（Gsα）， 涉及多种骨病，包括甲状旁腺功能亢进、詹森干骺端软骨发育不良 (due或纤维发育不良-McCune-Albright综合征（由于组成性激活PTHR 1） 活性Gsα），在遗传性疾病的情况下，可导致重大的发育和终身问题 和他们的骨架。在这三种情况下，唯一可用的治疗方法是手术或姑息治疗。蛋白激酶 A（PKA）是一种酶，其活性依赖于Gsα的活性和细胞内cAMP的水平。是 通过PTH与成骨细胞中PTHR 1的结合来调节。我们已经产生了一种诱导型成骨细胞特异性 通过胶原蛋白1-定向缺失调节亚基Prkar 1a的过度活跃PKA小鼠模型，并发现 在颅骨、长骨、椎骨和尾部的尾骨中的高骨转换表型，其模拟了 PTHR 1疾病我们和其他人已经表明PTH通过PKA控制基因对成骨细胞起作用 表达，部分通过盐诱导激酶（SIKs）的磷酸化抑制。这些激酶 张力磷酸化cAMP调节的转录辅激活因子（CRTC 1，2和3）和组蛋白 脱乙酰酶4/5（HDAC 4/5），将它们隔离在细胞质中。在PTH作用下，PKA介导的 抑制导致CRTC 2和HDAC 4/5磷酸化水平降低， CRTC 2/3和HDAC 4/5的易位，其介导破骨细胞生成基因Rankl的转录， 调节Mmp 13和抑制Sost转录。抑制、缺失或敲低SIK模拟了 PTH的影响我们最近测试了几种可能激活SIKs的药物， 在分化的小鼠颅骨成骨细胞中抑制PTH诱导的Rankl转录，并发现小的 分子，9117014，作为一个“假定的”SIK激活剂，以满足这些目标。从这些培养细胞的数据， 根据体内的初步数据，我们提出了一个假设，即SIKs的小分子激活剂将逆转 骨中PTH信号通路的不良影响。因此，这一具体目标 重新提交的R21申请是为了1）确定小分子对SIKs的激活是否会抑制PTH- 调节成骨细胞中的基因表达，通过a.对Rankl的PTH刺激进行剂量响应，B. 击倒SIK 2/3，c.测试对其他PTH调节基因的影响，2）评估小分子是否 在小鼠中，SIKs的活化剂将通过a.注入一种发展模式， 高骨转换，B。注射高骨转换的成人模型，c.注射一个成年的 甲状旁腺功能亢进，并进行全面的骨骼分析。这样做的结果将是高 影响，并可能导致进一步的临床前研究，可能形成的基础上，第一个疾病修饰口服 治疗甲状旁腺功能亢进、Jansen干骺端软骨发育不良或 发育不良-麦-奥二氏综合征。