Tetzner Anja, Gebolys Kinga, Meinert Christian, Klein Sabine, Uhlich Anja, Trebicka Jonel, Villacañas Óscar, Walther Thomas
From the Department of Pharmacology and Therapeutics, School of Medicine, School of Pharmacy, University College Cork (UCC), Cork, Ireland (A.T., K.G., C.M., A.U., T.W.); Departments Obstetrics (A.T., T.W.) and Pediatric Surgery (A.T., T.W.), University of Leipzig, Leipzig, Germany; Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University Heidelberg, Mannheim, Germany (C.M.); Department of Internal Medicine I, University of Bonn, Bonn, Germany (S.K., J.T.); and Computational Chemistry Department, Intelligent Pharma S.L., Barcelona, Spain (Ó.V.).
Hypertension. 2016 Jul;68(1):185-94. doi: 10.1161/HYPERTENSIONAHA.116.07572. Epub 2016 May 23.
Angiotensin (Ang)-(1-7) has cardiovascular protective effects and is the opponent of the often detrimental Ang II within the renin-angiotensin system. Although it is well accepted that the G-protein-coupled receptor Mas is a receptor for the heptapeptide, the lack in knowing initial signaling molecules stimulated by Ang-(1-7) prevented definitive characterization of ligand/receptor pharmacology as well as identification of further hypothesized receptors for the heptapeptide. The study aimed to identify a second messenger stimulated by Ang-(1-7) allowing confirmation as well as discovery of the heptapeptide's receptors. Ang-(1-7) elevates cAMP concentration in primary cells, such as endothelial or mesangial cells. Using cAMP as readout in receptor-transfected human embryonic kidney (HEK293) cells, we provided pharmacological proof that Mas is a functional receptor for Ang-(1-7). Moreover, we identified the G-protein-coupled receptor MrgD as a second receptor for Ang-(1-7). Consequently, the heptapeptide failed to increase cAMP concentration in primary mesangial cells with genetic deficiency in both Mas and MrgD Mice deficient in MrgD showed an impaired hemodynamic response after Ang-(1-7) administration. Furthermore, we excluded the Ang II type 2 receptor as a receptor for the heptapeptide but discovered that the Ang II type 2 blocker PD123319 can also block Mas and MrgD receptors. Our results lead to an expansion and partial revision of the renin-angiotensin system, by identifying a second receptor for Ang-(1-7), by excluding Ang II type 2 as a receptor for the heptapeptide, and by enforcing the revisit of such publications which concluded Ang II type 2 function by only using PD123319.
血管紧张素（Ang）-(1-7)具有心血管保护作用，是肾素-血管紧张素系统中通常具有有害作用的血管紧张素II的拮抗剂。尽管人们普遍认为G蛋白偶联受体Mas是这种七肽的受体，但由于缺乏对Ang-(1-7)刺激的初始信号分子的了解，阻碍了对配体/受体药理学的明确表征以及对该七肽其他假定受体的鉴定。该研究旨在确定一种由Ang-(1-7)刺激的第二信使，以确认并发现该七肽的受体。Ang-(1-7)可提高原代细胞（如内皮细胞或系膜细胞）中的环磷酸腺苷（cAMP）浓度。在受体转染的人胚肾（HEK293）细胞中以cAMP为读出指标，我们提供了药理学证据，证明Mas是Ang-(1-7)的功能性受体。此外，我们确定G蛋白偶联受体MrgD是Ang-(1-7)的另一种受体。因此，在Mas和MrgD均存在基因缺陷的原代系膜细胞中，该七肽未能提高cAMP浓度。MrgD基因缺陷的小鼠在给予Ang-(1-7)后血流动力学反应受损。此外，我们排除了血管紧张素II 2型受体作为该七肽的受体，但发现血管紧张素II 2型阻滞剂PD123319也可阻断Mas和MrgD受体。我们的研究结果导致了肾素-血管紧张素系统的扩展和部分修订，包括确定了Ang-(1-7)的另一种受体，排除了血管紧张素II 2型作为该七肽的受体，并促使人们重新审视那些仅使用PD123319得出血管紧张素II 2型功能的出版物。
