Angiotensin II induces nuclear factor- kappa B activation in cultured neonatal rat cardiomyocytes through protein kinase C signaling pathway.
Rat neonatal ventricular cardiomyocytes (RNVM) possess G protein-coupled AT(1)receptors for angiotensin II (AngII) that activate multiple intracellular pathways. To elucidate potential signaling mechanisms involved, we focussed on the nuclear transcription factor-kappa B (NF- kappa B) in RNVM culture. Using specific antibody to NF- kappa Bp65, immunolocalization of NF- kappa B was cytoplasmic in unstimulated cardiomyocytes, whereas NF- kappa B was translocated into the RNVM nucleus in response to AngII. This translocation was inhibited in the presence of calphostin C, a specific inhibitor of protein kinase C (PKC). Western blot analysis showed an increase of NF- kappa B in AngII-stimulated cardiomyocyte nuclear extracts as compared to controls. Biomolecular interaction analysis (BIA analysis) of NF- kappa B activation showed that only AngII-nuclear extracts bound to NF- kappa B consensus sequence with a high degree of affinity. This DNA-binding capacity was completely lost in calphostin C-treated cells. At transcriptional level in RNVM, AngII mediates the upregulation of matrix gelatinase (MMP-9), which is totally inhibited by calphostin C treatment. In conclusion, cardiomyocyte nuclear NF- kappa B translocation in response to Ang II via PKC pathway activates cardiomyocyte-specific transcription of MMP-9 and may activate transcription from responsive genes which are involved in cardiac hypertrophy process and/or cardiac remodeling.
Rouet-Benzineb
P
P
INSERM Unité U492, Faculté de Médecine, 8 rue du Général Sarrail, Créteil, 94010, France. rouet@im3.inserm.fr
Gontero
B
B
Dreyfus
P
P
Lafuma
C
C
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D018613:Microscopy, Confocal; D009132:Muscles / Q000166:cytology* / Q000201:enzymology; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D020349:Surface Plasmon Resonance; D013997:Time Factors; D051996:Transcription Factor RelA; D014158:Transcription, Genetic; D015854:Up-Regulation
D004791:Enzyme Inhibitors; D016328:NF-kappa B; D009281:Naphthalenes; D051996:Transcription Factor RelA; D000804:Angiotensin II; D004247:DNA; D011493:Protein Kinase C; D020780:Matrix Metalloproteinase 9; C058819:calphostin C