| Texto completo | |
| Autor(es): |
Dalla Costa, Ana Paula
;
Clemente, Carolina F. M. Z.
;
Carvalho, Hernandes F.
;
Carvalheira, Jose B.
;
Nadruz, Wilson, Jr.
;
Franchini, Kleber G.
Número total de Autores: 6
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Cardiovascular Research; v. 86, n. 3, p. 11-pg., 2010-06-01. |
| Resumo | |
Cardiac fibroblasts are activated by mechanical stress, but the underlying mechanisms involved remain poorly understood. In this study, we investigated whether focal adhesion kinase (FAK) plays a role in the activation of cardiac fibroblasts in response to cyclic stretch. Neonatal (NF-P3/80-third passage, 80% confluence) and adult (AF-P1/80-first passage, 80% confluence) rat cardiac fibroblasts were exposed to cyclic stretch (biaxial, 1 Hz), which enhanced FAK phosphorylation at Tyr397. Proliferation (anti-5-bromo-2'-deoxyuridine and anti-Ki67 nuclear labelling), differentiation into myofibroblasts (expression of alpha-smooth muscle actin-alpha-SMA), and the activity of matrix metalloproteinase-2 were equally enhanced in stretched NF-P3/80 and AF-P1/80. Treatment with the integrin inhibitor RGD peptide impaired FAK phosphorylation and increased apoptosis (TUNEL) in non-stretched and stretched NF-P3/80, whereas FAK silencing induced by small interfering RNA modestly enhanced apoptosis only in stretched cells. RGD peptide or FAK silencing suppressed the activation of NF-P3/80 invoked by cyclic stretch. In addition, NF-P3/80 depleted of FAK were defective in AKT Ser473, TSC-2 Thr1462, and S6 kinase Thr389 phosphorylation induced by cyclic stretch. The activation of NF-P3/80 invoked by cyclic stretch was prevented by pre-treatment with the mammalian target of rapamycin (mTOR) inhibitor rapamycin, whereas supplementation with the amino acid, leucine, activated S6K and rescued the stretch-induced activation of NF-P3/80 depleted of FAK. These findings demonstrate a critical role for the mTOR complex, downstream from FAK, in mediating the activation of cardiac fibroblasts in response to mechanical stress. (AU) | |
| Processo FAPESP: | 06/54878-3 - Patogênese da hipertrofia e insuficiência cardíacas: mecanismos ativados por estimulo mecânico |
| Beneficiário: | Kleber Gomes Franchini |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |