Long Non-Coding RNA NR_027324 Protects H9C2 Cells against Hypoglycemic and Hypoxic Injury by Interacting with microRNA-103-3p

This study explored the relationship among lncRNA NR_027324, miR-103-3p, and autophagy-related protein 5 (ATG5) in cardiomyocytes under hypoglycemic/hypoxic conditions.Bioinformatics and luciferase assays were used to investigate the interaction between NR_027324 and miR-103-3p. H9C2 cells cultured under hypoglycemic/hypoxic conditions were transfected with NR_027324 siRNA, overexpression vectors, and miR-103-3p mimics/inhibitors. Cell viability and damage were measured using MTT and LDH assays, respectively. qRT-PCR was performed to assess the mRNA levels of NR_027324, miR-103a-3p, and ATG5. Protein expressions were analyzed by Western blotting, and immunofluorescence was used to observe LC3-I/II expression.In hypoglycemic/hypoxic conditions, H9C2 cell viability decreased significantly, and LDH levels increased, indicating cell damage. Simultaneously, NR_027324 and ATG5 expressions were upregulated, while miR-103-3p was downregulated. Overexpression of NR_027324 enhanced cell viability and reduced LDH release. Conversely, knockdown of NR_027324 resulted in decreased cell viability and increased LDH release. In addition, knockdown of NR_027324 led to upregulation of miR-103-3p and downregulation of ATG5. Furthermore, the luciferase activity was significantly lower when miR-103-3p interacted with wildtype NR_027324, validating the binding between NR_027324 to miR-103-3p. The overexpression of NR_027324 led to downregulation of miR-103-3p, while its knockdown resulted in the upregulation of miR-103-3p. Lastly, NR_027324 overexpression alone significantly upregulated ATG5 expression, which was counteracted when NR_027324 and miR-103-3p were co-overexpressed.The findings of this study highlight the significance of NR_027324, miR-103-3p, and ATG5 in mediating the autophagy and apoptosis response of H9C2 cells under hypoglycemic/hypoxic stress, providing valuable insights into potential targets for therapeutic interventions in related cardiovascular conditions.