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心调节剂，因此对于骨矿化至关重要。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高，但PTH量增加。分子机制通常控制甲状旁腺细胞中PTH的转录调控很差。而且，pth 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。识别 PTH生产的转录或转录后调节剂对于我们对基本的理解很重要控制PTH生产的机制。在这里，我们已经确定了含BTB域的核蛋白KCTD1是PTH生产的新型关键调节剂，我们建议PTG中缺少KCTD1 通过丧失KCTD1介导的转录表示，导致一级甲状旁腺功能亢进 pth。我们生成了KCTD1LACZ报告基因小鼠和KCTD1 - / - 小鼠，并表明KCTD1在 PTG和缺乏KCTD1的小鼠的活性PTH血清水平高度增加和高钙血症。此外，KCTD1在人甲状旁腺组织中也表达。 KCTD1 - / - 小鼠发育骨矿化异常，如患有甲状旁腺功能亢进的患者。值得注意的是，某些骨骼异常在KCTD1 - / - 小鼠中，在头皮乳头综合征患者中观察到的骨缺损 KCTD1错义突变。解决问题是否在KCTD1 - / - 小鼠中观察到的异常是一个在PTG中特别丢失KCTD1的结果，或者KCTD1在其他器官中的功能是否贡献对于观察到的表型，我们已经产生了仅在PTG中缺乏KCTD1的小鼠并表达A 荧光记者等位基因，使我们能够从这些小鼠（PTH-CRE+KCTD1FL/FLEYFP+小鼠）中剖析PTG。我们将将这些小鼠的表型与在KCTD1 - / - 小鼠中观察到的表型进行比较，从而确定是否是观察到的甲状旁腺功能亢进和骨缺损是KCTD1缺乏症的结果 PTG。 KCTD1可以充当转录代表，并且可以作为规范Wnt/β-catenin的抑制剂信号。为了确定KCTD1如何调节PTH的产生，我们将在解剖的PTG中测试 CRE+KCTD1FL/FLEYFP+小鼠KCTD1是否通过转录表示或通过对PTH蛋白质稳定性或细胞分泌的影响以及它是否影响PTH产生的灵敏度响应钙的变化。我们将研究规范Wnt/β-catenin信号传导是否增加在缺乏KCTD1的PTG中，以及β-catenin抑制剂是否可以挽救增加的PTH产生。 RNA-seq 将识别PTG中KCTD1的下游目标。鉴于我们的广泛，科学前提很高初步数据和PTG特异性KCTD1 KO小鼠的可用性，并且提出的实验具有我们对涉及甲状旁腺功能亢进症的病理机制的理解的重要临床意义。