Expression of focal adhesion kinase in cardiac myocytes of hypertrophic ventricle

Objectives: To investigate the role of focal adhesion kinase (FAK) in the pathogenesis of cardiac hypertrophy induced by hypertension. Methods: Using immunofluorescent labeling, confocal microscopy and Western blotting, the expression and subcellular localization of FAK in the cardiac myocytes of left ventricle were determined in 2, 6, 12, and 18 month-old rats with spontaneously hypertensive heart failure (SHHF) along with age-matched control Wistar-Kyoto (WKY) rats. Results: There was no significant difference of FAK expression between 2 month-old SHHF and WKY rats(50.5 ± 6.9 vs. 49.8 ± 5.0, n = 6, P > 0.05). In contrast with the control groups, the expression of FAK significantly increased in 6, 12 and 18 month-old SHHF rats (130.6 ± 3.0 vs. 47.3 ± 1.3, 144.7 ± 5.4 vs. 46.4 ± 3.1, 141.4 ± 9.8 vs. 48.5 ± 2.2, each groups n = 6, P < 0.05) with FAK protein primarily cumulated in the intercalated disks and nuclei. Conclusions: FAK may play a role in the cell signaling transduction leading to cardiac hypertrophy, presumably through regulations of hypertrophic gene transcription and RNA processing.