LncRNA MEG3 accelerates apoptosis of hypoxic myocardial cells via FoxO1 signaling pathway.

Abstract

To explore the effects of long non-coding ribonucleic acid (lncRNA) maternally expressed gene 3 (MEG3) on the proliferation and apoptosis of hypoxic myocardial cells by regulating the expression of forkhead box O1 (FoxO1). The myocardial A10 cell lines were divided into myocardial cell group (group A), hypoxic myocardial cell group (group B), and hypoxic myocardial cell + transfection with lncRNA MEG3 mimic group (group C). The correlations of the adenosine triphosphate (ATP) concentration, the degree of apoptosis, and the proliferation with FoxO1 and FoxO3a proteins in the cells were observed via ATP assay, Cell Counting Kit-8 (CCK-8) assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, Western blotting, and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR), respectively. The ATP concentration in myocardial cells was the highest in group A (p<0.05), and it was higher in group B than that in group C (p<0.05). The results of the CCK-8 assay showed that the proliferation rate of the myocardial cells was the highest in group A and the lowest in group C (p<0.05), and it was significantly increased in group B compared with that in group C (p<0.05). The results of the TUNEL assay revealed that the normal cells displayed the purple color, and apoptotic cells displayed the green color. The myocardial cells were arranged orderly, and the number of apoptotic cells was smaller in group A, the number of apoptotic cells was significantly larger in group B than that in group A, and it was the largest in group C (p<0.05). Moreover, the results of Western blotting manifested that the concentrations of FoxO1 and FoxO3 proteins in myocardial cells were the lowest in group A (p<0.05), and they were significantly higher in group C than those in group B (p<0.05). According to the results of qRT-PCR, the mRNA expressions of FoxO1 and FoxO3 in myocardial cells were the lowest in group A (p<0.05), and they were remarkably lower in group B than those in group C (p<0.05). LncRNA MEG3 can increase the activity of FoxO1 to promote myocardial apoptosis in a hypoxic environment.