Regulation of PTH secretion by TRPC1

TRPC1 对 PTH 分泌的调节

基本信息

批准号：
10366048
负责人：
Wenhan Chang
金额：
$ 50.67万
依托单位：
UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
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：
2019-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10366048
关键词：
Adaptor Signaling Protein Address Affect Aging Area Biochemical Biochemistry Biological Biological Assay Biophysics Calcium-Sensing Receptors Cardiovascular system Cell Surface Receptors Cells Cellular biology Clathrin Adaptors Complex Data Disease of parathyroid glands Endocrine Glands Endocrine System Diseases Familial hypocalciuric hypercalcemia Forteo GTP-Binding Protein alpha Subunits Gene Deletion Genes Genetic Genetic Diseases Homeostasis Hormonal Hormone secretion Human Hypercalcemia Hyperparathyroidism Hyperplasia In Vitro Ion Channel Kidney Kidney Diseases Knockout Mice Knowledge Lead Link Mediating Mediator of activation protein Minerals Molecular Morbidity - disease rate Mus Mutation Organ Osteoporosis PTH gene Parathyroid Adenoma Parathyroid gland Pathogenicity Pathway interactions Patients Phenotype Physiological Physiology Population Receptor Signaling Recycling Regulation Resistance Role Secondary Hyperparathyroidism Secondary to Sigma Factor Signal Pathway Signal Transduction Testing Time base bone bone loss bone mass calcium excretion design enhancer-binding protein AP-2 experimental study extracellular genetic approach guanine nucleotide binding protein human disease in vivo insight knockout gene multidisciplinary novel therapeutics receptor response skeletal therapeutically effective urinary

项目摘要

Primary hyperparathyroidism is the one of the most common endocrine disorders. Primary hyperparathyroidism results from parathyroid adenomas while secondary hyperparathyroidism results from parathyroid gland hyperplasia in the setting of renal disease. Both conditions are associated with decreased expression of the Ca2+ sensing receptor (CaSR) which is required to suppress parathyroid hormone (PTH) secretion in the setting of hypercalcemia. Understanding the molecular mechanisms that regulate PTH secretion downstream of CaSR is critical for the discovery of new therapeutics to treat hyperparathyroidism and its associated morbidity. Here we show for the first time that Tprc1-null mice develop primary hyperparathyroidism, hypercalcemia, and low urinary calcium excretion mimicking the human disease Familial Hypocalciuric Hypercalcemia (FHH). FHH is a form of primary hypeparathyroidism and caused by inactivating mutations in CASR, GNA11 and AP2S1 encoding CaSR, the α11 subunit of the guanine nucleotide-binding protein, and the σ1 subunit of the AP2 clathrin-associated adaptor complex mediating recycling of cell surface receptors and channels, respectively. Thus, we tested whether TRCP1 function is directly linked to CaSR signaling. Biochemical, functional, and cell biological experiments in vitro show that TRPC1 is activated by CaSR involving the action of Gα11. We also show that TRPC1 physically interacts with AP2σ1. These data lead us to the hypothesis that TRPC1 is required for normal suppression of PTH secretion in the parathyroid gland by acting downstream of CaSR via Gα11. The interaction of TRPC1 with AP2σ1 increases the availability of TRPC1 for CaSR-induced signaling by accelerating recycling of inactivated TRPC1. In Aim 1, we will employ cell biological approaches to define the mechanism by which TRPC1 mediates CaSR-induced Ca2+ signaling and the role of Gα11 and AP2σ1 in this signaling pathway in cells derived from the parathyroid gland. In specific Aim 2, we will determine whether TRPC1 functions downstream of CaSR and Gα11 in vivo, by asking whether compound mice lacking Trpc1 and Casr or Gnα11/Gnαq genes in their parathyroid glands show more severe FHH-like phenotypes than phenotypes elicited by single gene deletions. Understanding the pathways that regulate PTH secretion could have a high impact on designing new and more effective and specific approaches to treat patients with primary as well as secondary hyperparathyroidism.

原发性甲状旁腺功能亢进症是最常见的内分泌疾病之一。甲状旁腺功能亢进症由甲状旁腺腺瘤引起，而继发性甲状旁腺功能亢进症由甲状旁腺腺瘤引起。肾脏疾病情况下的甲状旁腺增生与减少有关。抑制甲状旁腺激素 (PTH) 所需的 Ca2+ 传感受体 (CaSR) 的表达了解调节 PTH 的分子机制。 CaSR 下游的分泌对于发现治疗甲状旁腺功能亢进症的新疗法至关重要及其相关的发病率在这里我们首次展示了 Tprc1 缺失小鼠发生原发性。甲状旁腺功能亢进、高钙血症和尿钙排泄量低，类似于人类疾病家族性低钙尿性高钙血症 (FHH) 是原发性甲状腺功能亢进症的一种形式，由失活引起。 CASR、GNA11 和 AP2S1 中的突变编码 CaSR（鸟嘌呤核苷酸结合的 α11 亚基）蛋白和 AP2 网格蛋白相关接头复合物的 σ1 亚基介导细胞表面的回收因此，我们测试了 TRCP1 功能是否与 CaSR 直接相关。体外生化、功能和细胞生物学实验表明，TRPC1 被激活。 CaSR 涉及 Gα11 的作用，我们还表明 TRPC1 与 AP2σ1 发生物理相互作用。导致我们假设 TRPC1 是正常抑制甲状旁腺 PTH 分泌所必需的 TRPC1 与 AP2σ1 的相互作用增加了 CaSR 下游的腺体。通过加速失活的 TRPC1 的回收，TRPC1 可用于 CaSR 诱导的信号传导。在目标 1 中，我们。将采用细胞生物学方法来定义 TRPC1 介导 CaSR 诱导的 Ca2+ 的机制甲状旁腺细胞中 Gα11 和 AP2σ1 信号通路以及该信号通路中的作用。在具体目标 2 中，我们将通过以下方式确定 TRPC1 是否在体内 CaSR 和 Gα11 下游发挥作用：询问复合小鼠的甲状旁腺是否缺乏 Trpc1 和 Casr 或 Gnα11/Gnαq 基因显示出比单基因缺失引起的更严重的 FHH 样表型。调节 PTH 分泌的途径可能对设计新的、更有效的和治疗原发性和继发性甲状旁腺功能亢进症患者的具体方法。