Focal adhesion kinase mediates MEF2 and c-Jun activation by stretch: role in the activation of the cardiac hypertrophic genetic program

Autor(es)

Nadruz Júnior, Wilson ; Corat, Marcus A. F. ; Marin, Talita M. ; Pereira, Gonçalo A. Guimarães ; Franchini, Kleber G. ^[5]

• Tipo de documento: Artigo Científico
• Fonte: Cardiovascular Research; v. 68, n. 1, p. 87-97, Oct. 2005.
• Área do conhecimento: Ciências da Saúde - Medicina
• Assunto(s): Sistema cardiovascular Miocárdio Hipertrofia Miócitos cardíacos Proteína-tirosina quinases de adesão focal Expressão gênica Transdução de sinais

Resumo

We have previously reported that myocyte enhancer factor-2 (MEF2) transcription factors and c-Jun are rapidly activated by pressure overload and that these events are involved in the early activation of the myocardial hypertrophic genetic program. In this study, we investigated whether focal adhesion kinase (FAK) mediates the activation of MEF2 and c-Jun by mechanical stress in isolated neonatal rat ventricular myocytes (NRVMs). NRVMs were subjected to cyclic stretch up to 4 h and studied by immunoblotting, reverse transcriptase-polymerase chain reaction, laser confocal analysis, and reporter gene and electrophoretic mobility shift assays. Analysis was extended to NRVMs transfected with FAK-antisense oligodeoxynucleotide, treated with FAK/Src inhibitor PP2 or JNK/c-Jun inhibitor SP600125. Cyclic stretch increased c-Jun expression, JNK/c-Jun phosphorylation, and MEF2-DNA binding activity in NRVMs. Reporter gene assays indicated that the MEF2 site is critical to c-jun transcription in stretched cells. FAK-antisense transfection abolished MEF2 and c-jun promoter activation, while either FAK-antisense or PP2 treatment inhibited the stretch-induced c-Jun expression and JNK/c-Jun phosphorylation. Finally, treatment of NRVMs with the specific JNK/c-Jun inhibitor SP600125 significantly reduced the stretch-induced increase of atrial natriuretic factor promoter activity. The present data indicate that FAK regulates the activation of MEF2 and JNK/c-Jun pathways, which in turn have a key role in the early activation of the hypertrophic genetic program by mechanical stress in cardiac myocytes. (AU)

• Processo FAPESP: 00/05137-4 - Avaliação da expressão localização e função de proteínas sinalizadoras com microscopia confocal
• Beneficiário: Sara Teresinha Olalla Saad
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 01/11698-1 - Mecanismos de sinalização celular ativados por sobrecarga mecânica: implicações na hipertrofia e remodelamento miocárdicos
• Beneficiário: Kleber Gomes Franchini
• Modalidade de apoio: Auxílio à Pesquisa - Temático