| First Author | Kirca M | Year | 2015 |
| Journal | J Cell Mol Med | Volume | 19 |
| Issue | 4 | Pages | 815-25 |
| PubMed ID | 25678382 | Mgi Jnum | J:329760 |
| Mgi Id | MGI:6880378 | Doi | 10.1111/jcmm.12499 |
| Citation | Kirca M, et al. (2015) Interaction between connexin 43 and nitric oxide synthase in mice heart mitochondria. J Cell Mol Med 19(4):815-25 |
| abstractText | 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. |
