Delineating the role of CTF and NTF of Gpr126 in physiology and pathophysiology

描述 Gpr126 的 CTF 和 NTF 在生理学和病理生理学中的作用

• 批准号: 266138705
• 负责人: Professor Dr. Felix B. Engel
• 金额: --
• 依托单位: Professur für Experimentelle Nieren- und Herzkreislaufforschung (TRC)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/266138705?language=en
• 关键词: Delineating; role; CTF; NTF; Gpr126

The major activation mechanism of adhesion G protein-coupledreceptor (aGPCRs) signaling is the interaction of a cryptic tetheredagonist with the seven transmembrane domain. This agonist can beliberated by autocatalytical cleavage at the GPS motif within the GAINdomain, yielding an N-terminal fragment (NTF) and a C-terminalfragment (CTF) or through isomerization upon changes occurring atthe NTF such as ligand binding or mechanical force. The aGPCRGpr126 (Adgrg6) is essential for heart, ear, and Schwann celldevelopment. However, while Gpr126 knockout (KO) mice exhibit aheart and peripheral nerve phenotype, zebrafish mutants lacking theCTF exhibit only the peripheral nerve phenotype, suggesting that theNTF has a specific role in heart. Moreover, rescue experiments inzebrafish suggest that GPR126 has domain-specific functions. Yet,such a phenomenon has not been described for any other aGPCR, nodata in mouse are available, and it remains unclear whether receptorcleavage is important as well as which functions the individualdomains have. To demonstrate that the NTF has an independentfunction from the CTF, we have obtained or generated during the firstfunding period several animal models including Gpr126 reporter mice,conditional Gpr126 KO mice and several transgenic zebrafish lines.Analysis of these models identified several gross morphological aswell as cellular and molecular phenotypes upon alteration of Gpr126expression. During the second funding period we will continue thestructure-function analysis of Gpr126. An important focus of our workis to determine if the embryonic lethal phenotype in Gpr126 KO miceis indeed due to defective heart development and whether NTFexpression in endocardial cells is sufficient for proper heartdevelopment. Further, we will elucidate the role of Gpr126 in heartvalve development as our data suggest a role for Gpr126 inendothelial mesenchymal transformation. Finally, we will characterizethe role of Gpr126 during kidney physiology and pathophysiology. Ourdata indicate that Gpr126 is expressed in several renal cell types.Moreover, its expression is highly upregulated upon injury. Finally, ourdata suggest that the NTF might act in the heart as well as in thekidney in a paracrine manner. Collectively, we have generated a widevariety of tools that will allow us to delineate the role of CTF and NTFof Gpr126 in physiology and pathophysiology contributing to a betterunderstanding of aGPCR signaling and function.

粘附 G 蛋白偶联受体 (aGPCR) 信号传导的主要激活机制是隐秘的束缚激动剂与七个跨膜结构域的相互作用。这种激动剂可以通过 GAIN 结构域内 GPS 基序的自催化裂解来释放，产生 N 端片段 (NTF) 和 C 端片段 (CTF)，或者通过 NTF 发生变化（如配体结合或机械力）时的异构化来释放。 aGPCRGpr126 (Adgrg6) 对于心脏、耳朵和雪旺细胞发育至关重要。然而，虽然Gpr126敲除（KO）小鼠表现出心脏和周围神经表型，但缺乏CTF的斑马鱼突变体仅表现出周围神经表型，这表明NTF在心脏中具有特定作用。此外，斑马鱼救援实验表明 GPR126 具有域特异性功能。然而，这种现象尚未在任何其他 aGPCR 中得到描述，也没有小鼠数据，目前尚不清楚受体裂解是否重要以及各个结构域具有哪些功能。为了证明NTF具有独立于CTF的功能，我们在第一轮资助期间获得或产生了几种动物模型，包括Gpr126报告小鼠、条件性Gpr126 KO小鼠和几种转基因斑马鱼系。对这些模型的分析确定了几种Gpr126表达改变时的总体形态以及细胞和分子表型。在第二期资助期间，我们将继续对Gpr126进行结构功能分析。我们工作的一个重要重点是确定 Gpr126 KO 小鼠的胚胎致死表型是否确实是由于心脏发育缺陷所致，以及心内膜​​细胞中的 NTF 表达是否足以保证心脏的正常发育。此外，我们将阐明 Gpr126 在心脏瓣膜发育中的作用，因为我们的数据表明 Gpr126 在内皮间质转化中的作用。最后，我们将描述 Gpr126 在肾脏生理学和病理生理学中的作用。我们的数据表明，Gpr126 在多种肾细胞类型中表达。此外，其表达在损伤后高度上调。最后，我们的数据表明 NTF 可能以旁分泌方式在心脏和肾脏中发挥作用。总的来说，我们已经生成了各种各样的工具，使我们能够描述 Gpr126 的 CTF 和 NTF 在生理学和病理生理学中的作用，有助于更好地理解 aGPCR 信号传导和功能。