Regulation of Parathyroid Functions By G-Protein Coupled Receptors

G 蛋白偶联受体对甲状旁腺功能的调节

基本信息

批准号：
10693870
负责人：
Wenhan Chang
金额：
$ 43.23万
依托单位：
NORTHERN CALIFORNIA INSTITUTE/RES/EDU
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：
2019-09-12 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10693870
关键词：
Affect Agonist Aminobutyric Acids Automobile Driving Baclofen Binding Biochemical Biological Biological Assay Blood Circulation Calcium Signaling Calcium-Sensing Receptors California Cell Culture Techniques Cell physiology Cells Chronic Chronic Kidney Failure Complex Coupling Data Defect Diet Disease Disease of parathyroid glands Endocrine System Diseases Enzymes Family Feedback Fluorescence Resonance Energy Transfer G-Protein-Coupled Receptors GTP-Binding Proteins Heterodimerization Heterozygote Homeostasis Hormonal Hormone secretion Human Hypercalcemia Hyperparathyroidism Hypocalcemia Inherited Intestines Kidney Knock-out Knockout Mice Ligation Mediating Microscopy Minerals Modeling Molecular Mus Mutation Optics Organ Culture Techniques PTH gene Parathyroid Adenoma Parathyroid gland Patients Physiological Play Process Production Property Receptor Signaling Regimen Regulation Role San Francisco Second Messenger Systems Secondary Hyperparathyroidism Serum Signal Transduction Techniques Testing Universities antagonist autocrine biophysical tools bone efficacy evaluation extracellular in vivo insight interdisciplinary approach knockout gene nervous system disorder novel paracrine pharmacologic prevent protein activation receptor response side effect skeletal skeletal disorder theories

项目摘要

Parathyroid glands (PTGs) control mineral, hormonal, and skeletal homeostasis by adjusting parathyroid hormone (PTH) secretion in response to changes in serum [Ca2+]. It is well documented that activation of homomeric extracellular calcium-sensing receptor (CaSR) by raising serum [Ca2+] suppresses PTH secretion. However, the mechanisms promoting PTH secretion at hypocalcemic and various hyperparathyroidism (HPT) states due to CaSR-deficiency have not been explored. Our pilot data raise a novel hypothesis of a novel autocrine mechanism by which GABA and GABAB1R regulate G protein signaling of the CaSR to promote PTH secretion. Multi-disciplinary approaches to be performed by two highly complementary teams at University of Pittsburgh and University of California San Francisco will be employed to test this hypothesis through 3 specific aims. Aim 1 will first demonstrate the physiopathological relevance of the functional interaction between the CaSR and GABAB1R in PTGs by studying parathyroid cell (PTC)-specific GABAB1R and/or CaSR knockout mice in the contexts of hypocalcemia and different forms of HPT challenges (i.e., CaSR-deficiency or chronical kidney disease) in vivo and human PTGs excised from patients with primary and secondary HPT. Aim 2 will define the biological actions of Gad1/2 in regulating PTG functions by studying the effects of PTC-specific Gad1 and Gad2 double knockout in conditions of Ca2+ deficiency and various HPT states in mice and assessing Gad1/2 and GABA expression in human PTGs excised from patients with primary and secondary HPT. Aim 3 will delineate molecular mechanisms by which the CaSR/GABAB1R heteromers alter efficacy of G-protein activation of the CaSR and its consequence for PTH secretion and GABA production in cultured parathyroid-derived PTH-C1 cells. Optical (FRET, TIRF, BiFC) and biochemical techniques will be used to test the theory that PTH release and GABA synthesis are controlled through mechanisms involving the allosteric action of GABAB1R on CaSR signaling via receptor heteromerization that inhibits Ca2+-mediated Gq/11 and Gi signal transduction and promote PTH secretion. Successful completion of this project will help to develop new regimens to manage PTH hypo- or hyper-secretion and related endocrine and skeletal diseases and prevent unwanted side-effects of GABAB1R agonists and antagonists prescribed to patients with neurological disorders.

甲状旁腺（PTGS）通过调节甲状旁腺来控制矿物质，激素和骨骼稳态激素（PTH）分泌响应血清[Ca2+]的变化。有充分记录的激活通过升高血清[Ca2+]抑制PTH分泌，同源物细胞外钙感应受体（CASR）。但是，促进降钙症和各种甲状旁腺功能亢进症（HPT）的PTH分泌的机制由于CASR缺乏症的状态尚未探讨。我们的飞行员数据提出了一个新颖的假设 GABA和GABAB1R调节CASR的G蛋白信号以促进PTH的自分泌机制分泌。多学科的方法将由大学的两个高度互补的团队执行匹兹堡和加利福尼亚大学旧金山将通过3个特定的目标。 AIM 1将首先证明功能相互作用的生理病理学相关性 PTG中的CASR和GABAB1R通过研究甲状旁腺细胞（PTC）特异性Gabab1r和/或Casr敲除小鼠在低钙血症和不同形式的HPT挑战的情况下（即CASR缺乏症或慢性肾脏疾病）从原发性和继发性HPT患者中切除的体内和人类PTG。 AIM 2将定义通过研究PTC特异性GAD1和GAD2的影响，GAD1/2在调节PTG功能中的生物学作用在Ca2+缺乏症和小鼠中的各种HPT状态下的双重敲除，并评估GAD1/2和从原发性和继发性HPT患者中切除人PTG中的GABA表达。 AIM 3将描绘 CASR/GABAB1R异构体改变G蛋白激活的疗效的分子机制 CASR及其对培养的甲状旁腺衍生的PTH-C1中PTH分泌和GABA产生的后果细胞。光学（FRET，TIRF，BIFC）和生化技术将用于测试PTH释放的理论通过涉及GABAB1R对CASR的变构作用的机制来控制GABA合成通过受体异构化信号传导，抑制Ca2+介导的GQ/11和GI信号转导并促进 PTH分泌。该项目的成功完成将有助于制定新的方案，以管理PTH pth-dropo- 或超分泌以及相关的内分泌和骨骼疾病，并防止Gabab1r的不良副作用激动剂和拮抗剂为神经系统疾病的患者开了处方。