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.

过度活跃的甲状旁腺激素受体1（PTHR1）及其下游信号通路（GSα）为 詹森（Jansen）的形而上学软骨发育不全参与多种骨骼疾病，包括甲状旁腺功能亢进症 （由于组成型活性PTHR1）或纤维发育不良 - 麦卡纳 - 阿尔布赖特综合征（由于组成型 在遗传疾病的情况下，活跃的GSα可能会引起重大的发育和终身问题 用他们的骨骼。在这三种情况下，唯一的疗法是手术或姑息治疗。蛋白激酶 A（PKA）是一种酶，其活性取决于GSα的活性和CAMP的细胞水平。这是 在成骨细胞中由PTH与PTHR1结合的调节。我们已经产生了一个可诱导的成骨细胞特异性 通过胶原蛋白1导向prkar1a的胶原蛋白1导向缺失的小鼠模型 头骨，长骨，椎骨和尾骨的高骨转换表型，模仿尾巴 PTHR1疾病。我们和其他人表明，PTH对成骨细胞的作用通过PKA控制基因 表达部分是通过磷酸化盐诱导激酶（SIKS）抑制作用的。这些激酶 色调磷酸化的cAMP调节的转录共激活剂（CRTC1、2和3）和组蛋白 脱乙酰基酶4/5（HDAC4/5），将其隔离在细胞质中。在PTH动作时，PKA介导的Sik 抑制作用导致CRTC2和HDAC4/5磷酸化水平随后核而降低 CRTC2/3和HDAC4/5的易位，介导了破骨细胞基因的转录Rankl， MMP13的调节和SOST转录的抑制。 sik抑制，删除或敲除模拟 PTH的影响。我们最近测试了几种代理，以激活锡克斯 抑制PTH诱导的RANKL转录在分化小鼠钙钙细胞中的抑制作用，发现一个小的 分子，9117014，作为“推定” SIK激活剂，以适合这些目标。从培养物中细胞的这些数据和 在体内的初步数据，我们已经提出了这样的假设，即小分子激活剂会逆转 骨骼中PTH信号通路的不良影响。因此，特定的目的 重新提交的R21应用于1）确定小分子对锡克的激活是否会抑制PTH- 通过a。在成骨细胞中调节基因表达。对RANKL的PTH刺激进行剂量反应，b。 击倒sik2/3，c。测试对其他PTH调节基因的影响，2）评估是否小分子 Siks的激活剂将通过a抑制小鼠的高骨转换表型。注入一个发展模型 高骨更新，b。注射高骨更新的成人模型c。注射成人模型 甲状旁腺功能亢进，并进行完整的骨分析。这样做的结果将很高 影响并可能导致进一步的临床前研究，这可能构成首次调整疾病的口服的基础 甲状旁腺功能亢进症，詹森（Jansen）的形而上学软骨发育不全或纤维的治疗 发育不良 - 麦卡纳 - 阿尔布赖特综合征。