Enhancement of LncRNA-HFRL expression induces cardiomyocyte inflammation, proliferation, and fibrosis via the sequestering of miR-149-5p-mediated collagen 22A inhibition

BACKGROUND: Long non-coding ribonucleic acids (lncRNAs) are believed to play crucial roles in cardiovascular diseases; however, details of the underlying mechanisms by which this occurs remain unclear. METHODS: A mouse heart failure (HF) model was established using isoproterenol (ISO), and confirmed by immunostaining and echocardiography. RNA-sequencing was performed to screen the differential lncRNA expression profiles and heart failure relative lncRNA (HFRL) was selected as the target which was validated by quantitative real-time polymerase chain reaction (qRT-PCR). In HL-1 cells, the cardiac function, inflammatory, and fibrosis-related genes expression changes were examined by qRT-PCR after silencing of HFRL by lentivirus. Meanwhile, Cell Counting Kit-8 (CCK-8) assays were used to detect the effects of HFRL on the cell proliferation and viability. Reactive oxygen species (ROS) assays were also used to explore the role of HFRL in oxidative damage. Next, bioinformatics analysis was conducted to predict the potential binding microRNAs (mmu-miR-149-5p) to HFRL, which was confirmed by RNA-pulldown assays. The target gene of miR-149-5p was also predicted and further validated by Dual-luciferase reporter assays, qRT-PCR, and western blot. To investigate the synergistic regulatory effect of HFRL and miR-149-5p, HL-1 cells were infected with the lentivirus of HFRL with or without simultaneous knockdown of miR-149-5p. Then, qRT-PCR and western blot were used to examine cardiac function, inflammatory, and fibrosis-related gene expression changes, respectively. In HL-1 cells, CCK-8 assays were performed to detect the proliferation and viability. ROS assays were used to explore the oxidative damage. RESULTS: The administration of ISO induced mice fibrosis, inflammation, and HF. The in-vitro results showed that knockdown of HFRL suppressed cardiomyocyte proliferation and viability, attenuated inflammatory, cardiac function, and fibrosis-related gene expression, and promoted oxidative damage. HFRL was found to bind to mmu-miR-149-5p and inversely target the 3'-untranscripted region of the collagen 22A1 gene. Thus, HFRL affected cardiomyocyte inflammation, proliferation, viability, oxidative damage, and pro-fibrotic function via sequestration to miR-149-5p. CONCLUSIONS: The HFRL/miR-149-5p axis plays an important role in regulating cardiac inflammation, proliferation, and fibrosis via a synergistic effect, which suggests that HFRL might be a novel target for HF.