Figure 6. miR-21 decreased s100a8 expression in primarily isolated cardiomyocytes. (A) Heat map of cluster analysis showed dynamic changes of cardiac specific genes after miR-21 mimic treatment compared with the control. The levels of S100a8, Nr3C2 and NKX2.5 were measured by qRT-PCR in primary cardiomyocytes transfected with miR-21 mimic and inhibitor for 24 hours. (B) The protein expressions of S100a8, NFκB, calcineurin, and NFAT were measured by Western blot in primary cardiomyocytes. (C) The relative expression level of each protein was quantified by densitometry. miR-21 knockout (miR-21−/−) increased S100a8 and decreased NFκB, calcineurin, and NFAT expression in heart tissue of mice after angiotensin II (Ang II) treatment. The representative expressions and quantifications of S100a8, NFκB, calcineurin, and NFAT in wild type (WT) or miR-21−/− of mice were detected by Western blot. *P < 0.05 for difference from each group. (N = 4–6).