Protein Information

ID 756
Name integrins
Synonyms Alpha 11 precursor; HsT18964; ITGA11; Integrin; Integrin alpha 11; Integrin alpha 11 precursor; MSTP018; HsT18964s…

Compound Information

ID 954
Name SMA
CAS sodium 2-chloroacetate

Reference

PubMed Abstract RScore(About this table)
20038548 Dalla Costa AP, Clemente CF, Carvalho HF, Carvalheira JB, Nadruz W Jr, Franchini KG: FAK mediates the activation of cardiac fibroblasts induced by mechanical stress through regulation of the mTOR complex. Cardiovasc Res. 2010 Jan 22.
AIMS: 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. METHODS AND RESULTS: 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. CONCLUSIONS: 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.
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