Role of KCTD1 for primary hyperparathyroidism

KCTD1 在原发性甲状旁腺功能亢进症中的作用

基本信息

批准号：
9891937
负责人：
Alexander Georg Marneros
金额：
$ 19.71万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-03-15 至 2022-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9891937
关键词：
Address Affect Alleles BTB/POZ Domain Bone Density Bone Diseases Calcium Calcium-Sensing Receptors Calvaria Cell Proliferation Cell physiology Cell secretion Cells Clinical Data Defect Disease Ear FGFR1 gene Gastrointestinal tract structure Genes Genetic Transcription Homeostasis Human Hypercalcemia Hyperparathyroidism Hyperplasia Hypocalcemia result Kidney Knockout Mice Lead Mediating Missense Mutation Molecular Morphology Mus Nipples Nuclear Protein Organ Osteoblasts Osteoclasts Osteogenesis Osteoid PTH gene Parathyroid gland Pathway interactions Patients Phenocopy Phenotype Physiologic calcification Production Proteins Renal function Reporter Reporting Role Scalp structure Serum Serum Calcium Level Signal Transduction Syndrome Testing Tissues Transcript Transcription Repressor Transcriptional Regulation Vitamin D Vitamin D3 Receptor base beta catenin bone calcium phosphate clinically relevant clinically significant derepression experimental study extracellular gene repression improved inhibitor/antagonist innovation insight long bone male microCT novel prevent receptor response substantia spongiosa transcriptome sequencing

项目摘要

SUMMARY: Parathyroid hormone (PTH) is a central regulator of calcium and phosphate homeostasis and thereby essential for bone mineralization. In primary hyperparathyroidism parathyroid glands (PTGs) produce increased amounts of PTH despite normal or high serum calcium levels. The molecular mechanisms that normally control transcriptional regulation of PTH in parathyroid cells are poorly defined. Moreover, PTH production is also influenced by mechanisms that control its protein stability or secretion from cells. Identifying transcriptional or posttranscriptional regulators of PTH production is important for our understanding of the basic mechanisms that control PTH production. Here, we have identified the BTB-domain-containing nuclear protein KCTD1 as a novel key regulator of PTH production and we propose that lack of KCTD1 in PTGs leads to primary hyperparathyroidism through loss of KCTD1-mediated transcriptional repression of PTH. We generated KCTD1lacZ reporter mice and KCTD1-/- mice and show that KCTD1 is strongly expressed in PTGs and that mice lacking KCTD1 have highly increased active PTH serum levels and hypercalcemia. Moreover, KCTD1 is expressed in human parathyroid tissue as well. KCTD1-/- mice develop bone mineralization abnormalities, as they are seen in patients with hyperparathyroidism. Notably, some of the bone abnormalities in KCTD1-/- mice phenocopy bone defects seen in patients with Scalp-Ear-Nipple syndrome in which we identified KCTD1 missense mutations. To address the question if the abnormalities observed in KCTD1-/- mice are a consequence of loss of KCTD1 specifically in the PTGs or whether functions of KCTD1 in other organs contribute to the observed phenotype as well, we have generated mice that lack KCTD1 only in PTGs and express a fluorescent reporter allele, allowing us to dissect PTGs from these mice (PTH-Cre+KCTD1fl/flEYFP+ mice). We will compare the phenotypes in these mice with those observed in KCTD1-/- mice and thereby determine if the observed hyperparathyroidism and bone defects are a consequence of KCTD1 deficiency exclusively in the PTGs. KCTD1 can function as a transcriptional repressor and as an inhibitor of canonical Wnt/β-catenin signaling. To determine how KCTD1 regulates PTH production we will test in dissected PTGs of PTH- Cre+KCTD1fl/flEYFP+ mice whether KCTD1 regulates PTH production through transcriptional repression or through effects on protein stability or cellular secretion of PTH and whether it affects sensitivity of PTH production in response to changes in calcium. We will investigate whether canonical Wnt/β-catenin signaling is increased in PTGs that lack KCTD1 and whether β-catenin inhibitors can rescue the increased PTH production. RNA-Seq will identify downstream targets of KCTD1 in PTGs. Thus, the scientific premise is high given our extensive preliminary data and the availability of the PTG-specific KCTD1 KO mice, and the proposed experiments have an important clinical significance for our understanding of pathomechanisms involved in hyperparathyroidism.

摘要：甲状旁腺激素 (PTH) 是钙和磷酸盐稳态的中央调节剂，在原发性甲状旁腺功能亢进症中，甲状旁腺（PTG）产生。尽管血清钙水平正常或较高，但 PTH 含量增加的分子机制。通常控制甲状旁腺细胞中 PTH 转录调控的机制尚不明确。生产还受到控制其蛋白质稳定性或细胞分泌的机制的影响。 PTH 产生的转录或转录后调节因子对于我们了解 PTH 的基本原理非常重要。在这里，我们已经确定了含有 BTB 结构域的核。蛋白质 KCTD1 作为 PTH 产生的新型关键调节因子，我们建议 PTG 中缺乏 KCTD1 通过 KCTD1 介导的转录抑制的丧失导致原发性甲状旁腺功能亢进症我们生成了 KCTD1lacZ 报告小鼠和 KCTD1-/- 小鼠，并表明 KCTD1 在 PTG 和缺乏 KCTD1 的小鼠的活性 PTH 血清水平和高钙血症显着升高。此外，KCTD1 也在人甲状旁腺组织中表达，KCTD1-/- 小鼠也出现骨矿化。异常，如甲状旁腺功能亢进症患者所见，值得注意的是一些骨骼异常。在 KCTD1-/- 小鼠表型骨缺陷中观察到我们在头皮耳乳头综合征患者中发现的骨缺损 KCTD1 错义突变是否是 KCTD1-/- 小鼠中观察到的异常的问题。 KCTD1 在 PTG 中丢失的后果，或者 KCTD1 在其他器官中的功能是否有助于根据观察到的表型，我们培育了仅在 PTG 中缺乏 KCTD1 并表达荧光报告等位基因，使我们能够解剖这些小鼠（PTH-Cre+KCTD1fl/flEYFP+ 小鼠）的 PTG。将比较这些小鼠的表型与 KCTD1-/- 小鼠中观察到的表型，从而确定是否观察到的甲状旁腺功能亢进和骨缺陷是 KCTD1 缺乏的结果，仅在 KCTD1 可以作为转录抑制因子和经典 Wnt/β-连环蛋白的抑制剂。为了确定 KCTD1 如何调节 PTH 的产生，我们将在 PTH 的解剖 PTG 中进行测试。 Cre+KCTD1fl/flEYFP+ 小鼠 KCTD1 是否通过转录抑制调节 PTH 产生或通过对蛋白质稳定性或 PTH 细胞分泌的影响以及是否影响 PTH 产生的敏感性我们将研究经典 Wnt/β-catenin 信号传导是否增加。缺乏 KCTD1 的 PTG 以及 β-连环蛋白抑制剂是否可以挽救增加的 PTH 产量。将确定 PTG 中 KCTD1 的下游靶标，因此，鉴于我们的广泛研究，科学前提很高。 PTG特异性KCTD1 KO小鼠的初步数据和可用性，以及所提出的实验对于我们了解甲状旁腺功能亢进症的病理机制具有重要的临床意义。