Molecular Basis of Antidiabetogenic Hormone Action

抗糖尿病激素作用的分子基础

• 批准号: 9334841
• 负责人: GEORGE G HOLZ
• 金额: $ 43.72万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-18 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9334841
• 关键词: Adverse effects; Agonist; Beta Cell; Binding; Biological Assay; Blood Glucose; Cells; Complex; Confocal Microscopy; Coupled; Coupling; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dangerousness; Diagnosis; Diglycerides; Electric Capacitance; Exhibits; Exocytosis; Funding; G-Protein-Coupled Receptors; GLP-I receptor; Glucose; Goals; Growth Factor; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate Phosphohydrolases; HRAS gene; Hormones; Human; Hydrolysis; Injection of therapeutic agent; Insulin; Ion Channel; Islets of Langerhans; Kinetics; Knock-out; Knockout Mice; Link; Malignant Neoplasms; Mediating; Membrane; Metabolic; Modeling; Molecular; Mus; Nature; Non-Insulin-Dependent Diabetes Mellitus; Pancreas; Pancreatitis; Patients; Perfusion; Pharmacologic Substance; Phase; Phosphatidylinositol 4,5-Diphosphate; Potassium Channel; Production; Property; Protein Kinase C; Receptor Signaling; Secretory Vesicles; Signal Transduction; Signal Transduction Pathway; Stimulus; Structure of beta Cell of islet; Tamoxifen; Testing; analog; base; drug discovery; exenatide; glucagon-like peptide 1; glucose metabolism; in vivo; insulin secretagogues; insulin secretion; interest; islet; mimetics; novel; patch clamp; phospholipase C epsilon; public health relevance; response; scaffold; sensor; sulfonylurea receptor; treatment strategy; two-photon

DESCRIPTION (provided by applicant): Studies proposed here concern a novel phospholipase C-epsilon (PLCϵ) that we propose mediates beneficial blood glucose-lowering actions of the glucagon-like peptide-1 receptor (GLP-1R) agonist Byetta in patients with type 2 diabetes mellitus (T2DM). The central hypothesis we present is that there exists coupling of the pancreatic beta-cell GLP-1R to cAMP production with consequent activation of PLCϵ in order to potentiate glucose-stimulated insulin secretion (GSIS) from the islets of Langerhans. By understanding the nature of this unconventional cAMP signaling mechanism, we hope to further drug discovery efforts that seek to identify GLP-1R agonists that are pure insulin secretagogues and that do not induce dangerous side effects such as pancreatitis and cancer. Aim 1: Byetta might restore insulin secretion in T2DM by facilitating a "late step" of exocytosis that is under te control of PLCϵ. Using human islets or islets of PLCϵ KO mice, this hypothesis will be tested in perfusion or static incubation assays of GSIS. A first goal is to determine if PLCϵ mediates the action of Byetta to potentiate 1st and/or 2nd phase GSIS, or to potentiate "triggering" and "amplification" mechanisms of GSIS. Next, single cell patch clamp assays in combination with 2-photon confocal microscopy of secretory granule dynamics will be performed to test if PLCϵ activation explains diacylglycerol (DAG) and protein kinase C (PKC) mediated actions of Byetta to facilitate exocytosis. To evaluate the in vivo action of Byetta, glucoregulation will be studied using Pdx-1-hGLP1R:Glpr-/- mice in which there is a beta-cell specific KO of PLCϵ. Since Pdx-1-hGLP1R:Glpr-/- mice express the GLP-1R only in the pancreas, specific activation of the beta-cell GLP-1R by administered Byetta will be possible. We predict that a beta-cell specific KO of PLCϵ will disrupt the action of Byetta to potentiate GSIS in vivo. Aim 2: Byetta might also restore insulin secretion in patients with T2DM by sensitizing beta cells to the stimulatory effect of glucose metabolism. More specifically, we propose that Byetta acts via Epac2, Rap1, and PLCϵ to restore glucose metabolism-dependent closure of K-ATP channels in beta cells of T2DM patients. Our hypothesis embraces a new model of stimulus-secretion coupling in which the sulfonylurea receptor-1 (SUR1) subunit of K-ATP channels acts as a molecular scaffold to allow the formation of a signal transduction complex comprised of Epac2, Rap1, and PLCϵ. Importantly, we demonstrate that cAMP sensor Epac2 binds to SUR1, and that this interaction is facilitated by H-Ras GTPase acting at a Ras-association (RA) domain of Epac2. Thus, we hypothesize that Byetta acts in concert with growth factors or possibly secreted insulin to activate PLCϵ, to stimulate PIP2 hydrolysis, and to modulate the ATP and Mg-ADP sensitivity of K-ATP channels in order to close the channels. This hypothesis concerning a novel mechanism of ion channel modulation will be tested in assays of K-ATP channel activity using human islets or islets of Epac2 and PLCϵ knockout (KO) mice. Summary: The long-term goal of this project concerns our interest in determining the molecular basis for beneficial blood glucose-lowering properties of GLP-1R agonists in patients with T2DM.

描述（由申请人提供）：这里提出的研究涉及一种新型磷脂酶 C-ε (PLCϵ)，我们建议它介导胰高血糖素样肽 1 受体 (GLP-1R) 激动剂 Byetta 对 2 型糖尿病患者有益的降血糖作用我们提出的中心假设是，胰腺 β 细胞 GLP-1R 与 cAMP 的产生存在耦合。随后激活 PLCϵ 以增强朗格汉斯胰岛的葡萄糖刺激胰岛素分泌 (GSIS) 通过了解这种非常规 cAMP 信号传导机制的性质，我们希望进一步开展药物发现工作，寻求识别 GLP-1R 激动剂。纯胰岛素促分泌剂，不会引起危险的副作用，如胰腺炎和癌症。 目标 1：Byetta 可能通过促进“后期步骤”恢复 T2DM 的胰岛素分泌。使用人胰岛或 PLCϵ KO 小鼠的胰岛，将在 GSIS 的灌注或静态孵育测定中测试该假设。第一个目标是确定 PLCϵ 是否介导 Byetta 增强第一个作用。和/或第二阶段 GSIS，或增强 GSIS 的“触发”和“放大”机制 接下来，结合单细胞膜片钳测定。将进行分泌颗粒​​动力学的双光子共聚焦显微镜检查，以测试 PLCϵ 激活是否可以解释二酰基甘油 (DAG) 和蛋白激酶 C (PKC) 介导的 Byetta 促进胞吐作用的作用。 为了评估 Byetta 的体内作用，将研究葡萄糖调节。使用 Pdx-1-hGLP1R:Glpr-/- 小鼠，其中存在 PLCϵ 的 β 细胞特异性 KO。 Pdx-1-hGLP1R：Glpr-/- 小鼠仅在胰腺中表达 GLP-1R，通过施用 Byetta 特异性激活 β 细胞 GLP-1R 将是可能的，我们预测 PLCϵ 的 β 细胞特异性 KO 将是可能的。破坏 Byetta 在体内增强 GSIS 的作用 目标 2：Byetta 还可能通过使 β 细胞对葡萄糖的刺激作用敏感来恢复 T2DM 患者的胰岛素分泌。更具体地说，我们提出 Byetta 通过 Epac2、Rap1 和 PLCϵ 恢复 T2DM 患者 β 细胞中葡萄糖代谢依赖性 K-ATP 通道的关闭。 K-ATP 通道的磺酰脲受体 1 (SUR1) 亚基充当分子支架，允许形成由 Epac2、Rap1 和 PLCϵ 组成的信号转导复合物。证明 cAMP 传感器 Epac2 与 SUR1 结合，并且这种相互作用是通过作用于 Epac2 Ras 关联 (RA) 结构域的 H-Ras GTPase 促进的。因此，我们利用 Byetta 与生长因子或可能分泌的胰岛素协同作用来发挥作用。激活 PLCϵ，刺激 PIP2 水解，并调节 K-ATP 通道的 ATP 和 Mg-ADP 敏感性以关闭通道。这一假设涉及离子通道的新机制。将使用人胰岛或 Epac2 和 PLCϵ 敲除 (KO) 小鼠的胰岛来测试 K-ATP 通道活性的调节。 摘要：该项目的长期目标涉及我们对确定有益血糖的分子基础的兴趣。降低 T2DM 患者 GLP-1R 激动剂的特性。

项目成果

GPR119 Agonist AS1269574 Activates TRPA1 Cation Channels to Stimulate GLP-1 Secretion.

GPR119 激动剂 AS1269574 激活 TRPA1 阳离子通道以刺激 GLP-1 分泌。

• 发表时间: 2016-06
• 作者: Chepurny, Oleg G;Holz, George G;Roe, Michael W;Leech, Colin A
• 通讯作者: Leech, Colin A

PI3 kinases p110α and PI3K-C2β negatively regulate cAMP via PDE3/8 to control insulin secretion in mouse and human islets.

PI3 激酶 p110α 和 PI3K-C2β 通过 PDE3/8 负向调节 cAMP，以控制小鼠和人类胰岛的胰岛素分泌。

• 发表时间: 2016-07
• 影响因子: 8.1
• 作者: Kolic, Jelena;Manning Fox, Jocelyn E;Chepurny, Oleg G;Spigelman, Aliya F;Ferdaoussi, Mourad;Schwede, Frank;Holz, George G;MacDonald, Patrick E
• 通讯作者: MacDonald, Patrick E

Synthesis, in vitro biological investigation, and molecular dynamics simulations of thiazolopyrimidine based compounds as corticotrophin releasing factor receptor-1 antagonists.

作为促肾上腺皮质激素释放因子受体 1 拮抗剂的噻唑并嘧啶类化合物的合成、体外生物学研究和分子动力学模拟。

• 发表时间: 2021
• 影响因子: 5.1
• 作者: Elgiushy, Hossam R;Abou;Holz, George G;Chepurny, Oleg G;Pirmettis, Ioannis;Kakabakos, Sotirios;Karageorgos, Vlasios;Liapakis, George;Albohy, Amgad;Abouzid, Khaled A M;Hammad, Sherif F
• 通讯作者: Hammad, Sherif F

α7 Nicotinic Acetylcholine Receptor Regulates the Function and Viability of L Cells.

α7 烟碱乙酰胆碱受体调节 L 细胞的功能和活力。

• 发表时间: 2018-09-01
• 影响因子: 4.8
• 作者: Wang, Dawei;Meng, Qinghe;Leech, Colin A;Yepuri, Natesh;Zhang, Linlin;Holz, George G;Wang, Chunting;Cooney, Robert N
• 通讯作者: Cooney, Robert N

[99mTc]Tc-DGA1, a Promising CCK2R-Antagonist-Based Tracer for Tumor Diagnosis with Single-Photon Emission Computed Tomography.

[99mTc]Tc-DGA1，一种有前景的基于 CCK2R 拮抗剂的示踪剂，用于单光子发射计算机断层扫描肿瘤诊断。

• 发表时间: 2020
• 影响因子: 4.9
• 作者: Kaloudi, Aikaterini;Kanellopoulos, Panagiotis;Radolf, Thorsten;Chepurny, Oleg G;Rouchota, Maritina;Loudos, George;Andreae, Fritz;Holz, George G;Nock, Berthold Artur;Maina, Theodosia
• 通讯作者: Maina, Theodosia