Inhibition of lncRNA-PAX8-AS1-N directly associated with VEGF/TGF-β1/8-OhdG enhances podocyte apoptosis in diabetic nephropathy

Objective Diabetic nephropathy (DN), the microvascular complications of diabetes, is one of the world's public health hazard. But the detailed mechanism of the occurrence and development remains unclear. Oxidative stress caused by multiple factors is recognized as the main cause of disease, and it is also a research focus. Recently, long non-coding RNAs (lncRNAs) have been declared to involve in a large of important bioactivities in many different diseases. In our study, we aimed to verify whether lncRNA PAX8-AS1-N involved in protecting podocyte apoptosis and directly associated with VEGF/TGF-β1/8-OhdG levels in DN, and further investigated the detailed mechanism that PAX8-AS1-N regulated the pathological process. Materials and methods We used blood and urine samples of DN patients to detect the expression of lncRNA-PAX8-AS1-N and VEGF/TGF-β1/8-OhdG by ELISA and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Albuminuria level, relative PAX8-AS1-N and VEGF/TGF-β1/8-OhdG levels, and VEGF/TGF-β1/8-OhdG and cleaved-caspase-3 protein levels were detected by ELISA, qRT-PCR, and Western blot, respectively. CCK8 assay was used to measure the proliferation ability of conditionally immortalized mouse podocytes (MPC5). And we used the TUNEL assay to detect MPC5 apoptosis. Luciferase reporter assay was used to confirm the direct target of PAX8-AS-N and miR-17-5p in MPC5. Results We found that the lncRNA PAX8-AS1-N was lowly expressed and high expression of VEGF/TGF-β1/8-OhdG and high level of albuminuria in DN patients and high-glucose-treated MPC5. Besides, we proved that LV-PAX8-AS1-N decreased MPC5 apoptosis and suppressed the expression of VEGF/TGF-β1/8-OhdG in vitro experiment. At last, the overexpression of miR-17-5p markedly induced cell apoptosis in MPC5 with high glucose (HG) model. STAT3 reverses the effects of miR-17-5p overexpression in MPC5 with HG model. Conclusions Above that, we found that lncRNA PAX8-AS1-N/miR-17-5p/STAT3 axis was closely related the progression of DN, which could be a potential target for treating DN patients.