Rocca Carmine, Femminò Saveria, Aquila Giorgio, Granieri Maria C, De Francesco Ernestina M, Pasqua Teresa, Rigiracciolo Damiano C, Fortini Francesca, Cerra Maria C, Maggiolini Marcello, Pagliaro Pasquale, Rizzo Paola, Angelone Tommaso, Penna Claudia
Laboratory of Molecular and Cellular Cardiac Physiology, Department of Biology, Ecology and E.S., University of Calabria, Rende, Italy.
Department of Biological and Clinical Sciences, University of Turin, Turin, Italy.
Front Physiol. 2018 May 15;9:521. doi: 10.3389/fphys.2018.00521. eCollection 2018.
G protein-coupled estrogen receptor (GPER) is an estrogen receptor expressed in the cardiovascular system. G1, a selective GPER ligand, exerts cardiovascular effects through activation of the PI3K-Akt pathway and Notch signaling in normotensive animals. Here, we investigated whether the G1/GPER interaction is involved in the limitation of infarct size, and improvement of post-ischemic contractile function in female spontaneous hypertensive rat (SHR) hearts. In this model, we also studied Notch signaling and key components of survival pathway, namely PI3K-Akt, nitric oxide synthase (NOS) and mitochondrial K-ATP (MitoKATP) channels. Rat hearts isolated from female SHR underwent 30 min of global, normothermic ischemia and 120 min of reperfusion. G1 (10 nM) alone or specific inhibitors of GPER, PI3K/NOS and MitoKATP channels co-infused with G1, just before I/R, were studied. The involvement of Notch1 was studied by Western blotting. Infarct size and left ventricular pressure were measured. To confirm endothelial-independent G1-induced protection by Notch signaling, H9c2 cells were studied with specific inhibitor, -[-(3,5 difluorophenacetyl)-L-alanyl]--phenylglycine -butyl ester (DAPT, 5 μM), of this signaling. Using DAPT, we confirmed the involvement of G1/Notch signaling in limiting infarct size in heart of normotensive animals. In the hypertensive model, G1-induced reduction in infarct size and improvement of cardiac function were prevented by the inhibition of GPER, PI3K/NOS, and MitoKATP channels. The involvement of Notch was confirmed by western blot in the hypertensive model and by the specific inhibitor in the normotensive model and cardiac cell line. Our results suggest that GPERs play a pivotal role in mediating preconditioning cardioprotection in normotensive and hypertensive conditions. The G1-induced protection involves Notch1 and is able to activate the survival pathway in the presence of comorbidity. Several pathological conditions, including hypertension, reduce the efficacy of ischemic conditioning strategies. However, G1-induced protection can result in significant reduction of I/R injury also female in hypertensive animals. Further studies may ascertain the clinical translation of the present results.
G蛋白偶联雌激素受体（GPER）是一种在心血管系统中表达的雌激素受体。G1是一种选择性GPER配体，在血压正常的动物中，它通过激活PI3K-Akt途径和Notch信号传导发挥心血管效应。在此，我们研究了G1/GPER相互作用是否参与雌性自发性高血压大鼠（SHR）心脏梗死面积的限制以及缺血后收缩功能的改善。在该模型中，我们还研究了Notch信号传导以及生存途径的关键成分，即PI3K-Akt、一氧化氮合酶（NOS）和线粒体KATP（MitoKATP）通道。从雌性SHR分离的大鼠心脏经历30分钟的整体常温缺血和120分钟的再灌注。研究了单独使用G1（10 nM）或在缺血/再灌注（I/R）前与G1共同输注的GPER、PI3K/NOS和MitoKATP通道的特异性抑制剂。通过蛋白质印迹法研究Notch1的参与情况。测量梗死面积和左心室压力。为了通过Notch信号传导确认G1诱导的非内皮依赖性保护作用，使用该信号传导的特异性抑制剂-[-（3,5-二氟苯乙酰基）-L-丙氨酰基]--苯甘氨酸丁酯（DAPT，5μM）对H9c2细胞进行了研究。使用DAPT，我们证实了G1/Notch信号传导参与限制血压正常动物心脏的梗死面积。在高血压模型中，抑制GPER、PI3K/NOS和MitoKATP通道可阻止G I诱导的梗死面积减小和心脏功能改善。在高血压模型中通过蛋白质印迹法以及在血压正常模型和心肌细胞系中通过特异性抑制剂证实了Notch的参与。我们的结果表明，GPER在介导血压正常和高血压状态下的预处理心脏保护中起关键作用。G1诱导的保护涉及Notch1，并且在存在合并症的情况下能够激活生存途径。包括高血压在内的几种病理状况会降低缺血预处理策略的疗效。然而，G1诱导的保护作用也可显著降低高血压动物雌性中的I/R损伤。进一步的研究可能会确定本研究结果的临床转化情况。
