Interaction between Connexin 43 and nitric oxide synthase in mice heart mitochondria

Journal of Cellular and Molecular Medicine

Mücella Kirca¹  Petra Kleinbongard³  Daniel Soetkamp¹  Jacqueline Heger¹  Csaba Csonka²  Péter Ferdinandy⁴ 

[1] Physiologisches Institut, Justus-Liebig-Universität, Giessen, Germany;Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged, Hungary;Institute for Pathophysiology, West German Heart and Vascular Center, University Schhool of Medicine Essen, Essen, Germany;Pharmahungary Group, Szeged, Hungary

关键词: connexin;    nitric oxide;    heart;    mitochondria;   

DOI  :  10.1111/jcmm.12499

来源: Wiley

【 摘 要 】

Abstract

Connexin 43 (Cx43), which is highly expressed in the heart and especially in cardiomyocytes, interferes with the expression of nitric oxide synthase (NOS) isoforms. Conversely, Cx43 gene expression is down-regulated by nitric oxide derived from the inducible NOS. Thus, a complex interplay between Cx43 and NOS expression appears to exist. As cardiac mitochondria are supposed to contain a NOS, we now investigated the expression of NOS isoforms and the nitric oxide production rate in isolated mitochondria of wild-type and Cx43-deficient (Cx43^Cre-ER(T)/fl) mice hearts. Mitochondria were isolated from hearts using differential centrifugation and purified via Percoll gradient ultracentrifugation. Isolated mitochondria were stained with an antibody against the mitochondrial marker protein adenine-nucleotide-translocator (ANT) in combination with either a neuronal NOS (nNOS) or an inducible NOS (iNOS) antibody and analysed using confocal laser scanning microscopy. The nitric oxide formation was quantified in purified mitochondria using the oxyhaemoglobin assay. Co-localization of predominantly nNOS (nNOS: 93 ± 4.1%; iNOS: 24.6 ± 7.5%) with ANT was detected in isolated mitochondria of wild-type mice. In contrast, iNOS expression was increased in Cx43^Cre-ER(T)/fl mitochondria (iNOS: 90.7 ± 3.2%; nNOS: 53.8 ± 17.5%). The mitochondrial nitric oxide formation was reduced in Cx43^Cre-ER(T)/fl mitochondria (0.14 ± 0.02 nmol/min./mg protein) in comparison to wild-type mitochondria (0.24 ± 0.02 nmol/min./mg). These are the first data demonstrating, that a reduced mitochondrial Cx43 content is associated with a switch of the mitochondrial NOS isoform and the respective mitochondrial rate of nitric oxide formation.

【 授权许可】

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© 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

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