Regulation of Long-Chain Non-Coding RNA Nuclear Paraspeckle Assembly Transcript 1 in Hypoxia/Reoxygenation Cardiomyocyte Impairment Through miR-199a-5 Targeting

Abstract

To investigate the targeting mechanism of long-chain non-coding RNA NEAT1 (LncRNA NEAT1) for microRNA-199a-5p (miR-199a-5p), to regulate hypoxia/reoxygenation (H/R) in myocardial cell impairment. Rat cardiomyocytes were cultured in vitro and divided into the: Con group, H/R group, H/R + si-NC group, H/R + si-NEAT1 group, H/R + miR-NC group, H/R + miR-199a-5p group, H/R + si-NEAT1 + anti-miR-NC group, and H/R + si-NEAT1 + anti-miR-199a-5p group. Levels of endocellular NEAT1 and miR-199a-5p were evaluated with qRT-PCR. Changes in endocellular LDH, SOD, and MDA levels were observed. Annexin V-FITC/PI staining was applied to test apoptosis rates. Western blotting was used to test Bcl-2 and Bax protein levels. The double luciferase reporter gene was used to test the targeting association between NEAT1 and miR-199a-5p. In comparison with the Con group, H/R showed significantly increased NEAT1 levels (P < 0.05), significantly decreased miR-199a-5p levels (P < 0.05), significantly decreased SOD and Bcl-2 levels (P < 0.05), and significantly increased apoptosis rates and LDH, SOD levels (P < 0.05). Cardiomyocyte levels of LDH, SOD, and apoptosis rates was significantly reduced following NEAT1 expression inhibition, or miR-199a-5p overexpression (P < 0.05), and SOD and Bcl-2 levels increased significantly (P < 0.05). Overexpression of miR-199a-5p can significantly reduce the fluorescence intensity of the luciferase reporter gene. No significant change in luciferase activity was observed after binding site mutation. Interference with miR-199a-5p expression can inhibit the protective action of NEAT1 expression on cardiomyocyte impairment. Inhibiting NEAT1 expression can inhibit cardiomyocyte apoptosis by up-regulating miR-199a-5p expression, enhancing the clearance ability of oxygen free radicals, and protecting against H/R cardiomyocyte impairment.