Research Paper Volume 13, Issue 18 pp 22242—22255

miR-21 regulates ischemic neuronal injury via the p53/Bcl-2/Bax signaling pathway

Overexpression of miR-21 down regulated p53 expression, while inhibition of miR-21 up regulated p53 expression following ischemia in vitro. (A) The modulation of miR-21 expression by transfecting different concentrations of miR-21 mimics into primary cultured neurons was confirmed by qRT-PCR. (B, C) The expression of p53 mRNA (B) and protein (C) in neurons decreased in a concentration-dependent manner with the increase of the concentration of miR-21 mimics. (D) The modulation of miR-21 expression by transfecting different concentrations of miR-21 inhibitors into primary cultured neurons was confirmed by qRT-PCR. (E, F) The expression of p53 mRNA (E) and protein (F) in neurons increased in a concentration-dependent manner with the increase of the concentration of miR-21 inhibitors. (G, H) The modulation of p53 mRNA (G) and protein (H) levels by transfecting different concentrations of p53-siRNAs into primary cultured neurons were confirmed by qRT-PCR and western blot. (I) qRT-PCR showed that the expression level of miR-21 did not change significantly with the decrease of p53 expression. All experiments were independently repeated three times. *, compared with blank control. *P≤0.05; **P≤0.01.

Figure 2. Overexpression of miR-21 down regulated p53 expression, while inhibition of miR-21 up regulated p53 expression following ischemia in vitro. (A) The modulation of miR-21 expression by transfecting different concentrations of miR-21 mimics into primary cultured neurons was confirmed by qRT-PCR. (B, C) The expression of p53 mRNA (B) and protein (C) in neurons decreased in a concentration-dependent manner with the increase of the concentration of miR-21 mimics. (D) The modulation of miR-21 expression by transfecting different concentrations of miR-21 inhibitors into primary cultured neurons was confirmed by qRT-PCR. (E, F) The expression of p53 mRNA (E) and protein (F) in neurons increased in a concentration-dependent manner with the increase of the concentration of miR-21 inhibitors. (G, H) The modulation of p53 mRNA (G) and protein (H) levels by transfecting different concentrations of p53-siRNAs into primary cultured neurons were confirmed by qRT-PCR and western blot. (I) qRT-PCR showed that the expression level of miR-21 did not change significantly with the decrease of p53 expression. All experiments were independently repeated three times. *, compared with blank control. *P≤0.05; **P≤0.01.