LncRNA NEAT1/microRNA-124 regulates cell viability, inflammation and fibrosis in high-glucose-treated mesangial cells

Long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) has been frequently found to be dysregulated, which contributes to diabetes-related complications. The present study aimed to explore the effect of knockdown on mouse mesangial cell (MMC) viability, apoptosis, inflammation and fibrosis in an in vitro model of diabetic nephropathy (DN). The SV40 MES13 MMC cell line was first cultured with high glucose to establish an in vitro MMC DN cell model. Lnc-NEAT1 shRNA or the negative control shRNA were transfected into MMC DN cells, followed by the measurement of cell viability, apoptosis, inflammation, fibrosis and microRNA (miR)-124 expression, a known target of lnc-NEAT1, using Cell Counting Kit-8, flow cytometry, ELISA, western blotting [Capain1 (capn1), β-catenin (CTNNB1), cleaved caspase 3, cleaved poly-(ADP ribose) polymerase, fibronectin and Collagen] and reverse transcription-quantitative PCR (Capn1, CTNNB1, lnc-NEAT1, fibronectin, collagen and miR-124), respectively. In rescue experiments, the miR-124 and negative control inhibitor were co-transfected into lnc-NEAT1-downregulated cells, following which cell viability, apoptosis, inflammation, fibrosis, capn1 and CTNNB1 expression were measured. Lnc-NEAT1 expression was increased in high glucose-treated cells compared with that in normal glucose-treated cells and osmotic control cells, suggesting that lnc-NEAT1 is overexpressed in the MMC DN cell model. In the MMC DN cell model, lncRNA-NEAT1 knockdown enhanced cell apoptosis but reduced cell viability and the secretion of inflammatory cytokines in the supernatant (IL-1β, IL-8, monocyte chemotactic protein 1 and TNF-α), in addition to reducing the expression of fibrosis markers fibronectin and collagen I in the lysates. Lnc-NEAT1 knockdown increased miR-124 expression. Furthermore, transfection with the miR-124 inhibitor reduced cell apoptosis but increased cell viability, inflammation and fibrosis in lnc-NEAT1-downregulated MMC DN cells. miR-124 inhibitor transfection also increased the expression levels of Capn1 and CTNNB1. Taken together, the findings of the present study demonstrated that lnc-NEAT1 knockdown was able to attenuate MMC viability, inflammation and fibrosis by regulating miR-124 expression and the Capn1/β-catenin signaling pathway downstream. Therefore, Lnc-NEAT1 may serve as a potential therapeutic target for DN.