Intracrine endothelin signaling evokes IP3-dependent increases in nucleoplasmic Ca^2 + in adult cardiac myocytes

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• 作者：Cl¨¦mence Merlen ; Nada Farhat ; Xiaoyan Luo ; David Chatenet ; Artavazd Tadevosyan ; Louis R. Villeneuve ; Marc-Antoine Gillis ; Stanley Nattel ; Eric Thorin ; Alain Fournier ; Bruce G. Allen
• 关键词：2-APB ; 2-aminoethoxydiphenyl borate ; Ang II ; angiotensin II ; ¦Á-AR ; ¦Á-adrenergic receptor ; [Ca2  ; +]n ; nucleoplasmic free calcium concentration ; CaMKII ; Ca2  ; +/calmodulin-dependent protein kinase II ; DMNB ; 4 ; 5-dimethoxynitrobenzyl group ; DNA ; deox
• 刊名：Journal of Molecular and Cellular Cardiology
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：62
• 期：Complete
• 页码：189-202
• 全文大小：2465 K

文摘

Endothelin receptors are present on the nuclear membranes in adult cardiac ventricular myocytes. The objectives of the present study were to determine 1) which endothelin receptor subtype is in cardiac nuclear membranes, 2) if the receptor and ligand traffic from the cell surface to the nucleus, and 3) the effect of increased intracellular ET-1 on nuclear Ca^2 + signaling. Confocal microscopy using fluorescently-labeled endothelin analogs confirmed the presence of ETB at the nuclear membrane of rat cardiomyocytes in skinned-cells and isolated nuclei. Furthermore, in both cardiac myocytes and aortic endothelial cells, endocytosed ET:ETB complexes translocated to lysosomes and not the nuclear envelope. Although ETA and ETB can form heterodimers, the presence or absence of ETA did not alter ETB trafficking. Treatment of isolated nuclei with peptide: N-glycosidase F did not alter the electrophoretic mobility of ETB. The absence of N-glycosylation further indicates that these receptors did not originate at the cell surface. Intracellular photolysis of a caged ET-1 analog ([Trp-ODMNB²¹]ET-1) evoked an increase in nucleoplasmic Ca^2 + ([Ca^2 +]_n) that was attenuated by inositol 1,4,5-trisphosphate receptor inhibitor 2-aminoethoxydiphenyl borate and prevented by pre-treatment with ryanodine. A caged cell-permeable analog of the ETB-selective antagonist IRL-2500 blocked the ability of intracellular cET-1 to increase [Ca^2 +]_n whereas extracellular application of ETA and ETB receptor antagonists did not. These data suggest that 1) the endothelin receptor in the cardiac nuclear membranes is ETB, 2) ETB traffics directly to the nuclear membrane after biosynthesis, 3) exogenous endothelins are not ligands for ETB on nuclear membranes, and 4) ETB associated with the nuclear membranes regulates nuclear Ca^2 + signaling.