LncRNA TCF7 triggered endoplasmic reticulum stress through a sponge action with miR-200c in patients with diabetic nephropathy.

OBJECTIVE: To investigate the functions and mechanisms of long non-coding RNA TCF7 (LncTCF7) in patients with diabetic nephropathy (DN). PATIENTS AND METHODS: LncTCF7 and miR-200c expressions in DN (+) were detected by Real Time-Polymerase Chain Reaction (RT-PCR). In the established high-glucose group (HG) model, RT-PCR and Western blot were used to detect the expressions of lncTCF7 and key apoptotic genes. The effect of podocyte endoplasmic reticulum (ER) stress was detected in high glucose conditions after lncTCF7 siRNA transfection. The miR-200c level was detected in lncTCF7 overexpressing cell model and the luciferase reporter gene assay was performed to verify the potential binding site of lncTCF7 with miR-200c. Furthermore, ER stress-associated genes were detected in patients with DN. Finally, in the HG model, the levels of ER stress were detected by WB after transfection with miR-200c inhibitor and lncTCF7 siRNA with miR-200c mimics. RESULTS: Results showed that the lncTCF7 expression was up-regulated, while miR-200c was significantly downregulated in patients with DN (+). In the HG model, the expression of lncTCF7 was significantly increased and some key ER stress-associated genes, such as CHOP, XBP1, and cleaved caspase3, were significantly increased, while the anti-apoptotic protein Bcl-2 was significantly decreased. However, after inhibiting the lncTCF7 expression, these gene levels were reversed. In lncTCF7 overexpressing cells, miR-200c expression was significantly down-regulated compared with the control (p<0.05) and the luciferase reporter gene assay results showed that lncTCF7 could directly bind to miR-200c. In the HG model, after inhibiting lncTCF7 expression, the miR-200c level was increased, while the ER stress-associated proteins CHOP, XBP1, and cleaved caspase3 were significantly repressed. However, these proteins were reversed after inhibiting miR-200c expression. In addition, the expressions of ER stress-associated protein and apoptotic protein in human DN patients were consistent with HG cell model. CONCLUSIONS: LncRNA TCF7 triggered endoplasmic reticulum stress through a sponge action with miR-200c in patients with diabetic nephropathy.