[Effect and molecular mechanism of interferon-α on podocyte apoptosis induced by hepatitis B virus X protein].

OBJECTIVE: To investigate the effect and molecular mechanism of interferon-α (INF-α) on the apoptosis of the mouse podocyte cell line MPC5 induced by hepatitis B virus X (HBx) protein. METHODS: MPC5 cells were transfected with the pEX plasmid carrying the HBx gene. RT-PCR was used to measure the mRNA expression of HBx at different time points. MPC5 cells were divided into 4 groups: control group (MPC5 cells cultured under normal conditions), INF-α group (MPC5 cells cultured with INF-α), HBx group (MPC5 cells induced by HBx), and HBx+INF-α group (MPC5 cells induced by HBx and cultured with INF-α). After 48 hours of intervention under different experimental conditions, flow cytometry was used to measure the apoptosis of MPC5 cells, and quantitative real-time PCR and Western blot were used to measure the mRNA and protein expression of slit diaphragm-related proteins (nephrin, CD2AP, and synaptopodin) and the cytoskeleton-related protein transient receptor potential cation channel 6 (TRPC6). RESULTS: MPC5 cells transfected by pEX-HBx had the highest expression of HBx mRNA at 48 hours after transfection (P<0.05). Compared with the control, INF-α and HBx+INF-α groups, the HBx group had a significant increase in the apoptosis rate of MPC5 cells (P<0.05). Compared with the control and INF-α groups, the HBx group had significant reductions in the mRNA and protein expression of nephrin, synaptopodin, and CD2AP and significant increases in the mRNA and protein expression of TRPC6 (P<0.05). Compared with the HBx group, the HBx+INF-α group had significant increases in the mRNA and protein expression of nephrin, synaptopodin, and CD2AP and significant reductions in the mRNA and protein expression of TRPC6 (P<0.05). CONCLUSIONS: INF-α can inhibit the apoptosis of podocytes induced by HBx, possibly through improving the abnormal expression of slit diaphragm-related proteins (CD2AP, nephrin, and synaptopodin) and cytoskeleton-related protein (TRPC6) induced by HBx.

[Dexamethasone Blocks Adriamycin-induced Podocytes'Mobility via Impacting Nephrin Expression].

OBJECTIVE: To explore how dexamethasone (Dex) directly restores kidney podocyte function in adriamycin (ADR)-induced nephrotic model and the effects of Dex on the motility of podocytes, to analyze whether nephrin is a key signal molecule in the process. METHODS: The cultured podocytes were divided into three growps: ADR treated group, ADR+Dex group, blank control group. The analyses of podocytes function were performed using scrape-wound, Transwell migration assays and FITC-BSA. Quantitative real-time PCR and Western blot were used to test the expression of nephrin. Male SD rats were used to generate ADR-induced nephrology model, and randomly divided into three groups: ADR group, ADR+Dex group and normal group. At 7 d, 14 d, 21 d and 28 d after ADR injection, 24 h urine protein was measured as well. Podocyte foot process effacement was observed under transmission electron microscopy. RESULTS: Podocytes' motility, permeability of a monolayer of podocytes incubated with FITC-BSA, the expression of nephrin were higher in ADR group than those in blank control group (P<0.05); on the contrary, the indexes above in Dex+ADR group were decreased when compared with ADR group (P<0.05). 24 h urine protein increased significantly at day 14 (vs. normal group P<0.001) and peaked at day 28 in ADR rats (vs. normal group P<0.001), whereas decreased at day 14, 21 and 28 in Dex+ADR group (vs. ADR group, P<0.001). The FWP of ADR-treated rats was greater than normal group and Dex+ADR group (P<0.01). CONCLUSION: Dex impacts the expression of nephrin, relieves the enhanced motility induced by ADR and decreases urine protein level.

Erratum: Protective effect of astragalosides from Radix Astragali on adriamycin-induced podocyte injury.

[This corrects the article DOI: 10.3892/etm.2018.5933.].

Protective effect of astragalosides from Radix Astragali on adriamycin-induced podocyte injury.

Nephrotic syndrome (NS) is the most common kidney disease in clinical practice and may lead to end-stage renal failure. Astragalosides (AST) have been clinically tested for the treatment of NS, but their mechanism of action has remained to be elucidated. The aim of the present study was to investigate the effect of AST on the structure and function of podocytes with adriamycin (ADR)-induced damage and to elucidate the underlying molecular mechanisms. The mouse podocyte clone 5 (MPC5) immortalized mouse podocyte cell line was treated with 0.5 µmol/l ADR to establish a podocyte injury model. The MPC5 podocytes were divided into a control group, a podocyte injury group and a low-, medium- and high-concentration AST treatment group. The results indicated that the survival rate of the podocyte injury group was significantly decreased compared with that in the control group and each AST-treated group had an increased survival rate compared with that in the podocyte injury group. Furthermore, each dose of AST significantly inhibited the ADR-associated increases the levels of lactate dehydrogenase and malondialdehyde and the decrease in the activity of superoxide dismutase in MPC5 podocytes. In addition, AST improved the migration ability of MPC5 podocytes and suppressed the cytoskeletal rearrangement associated with ADR-induced damage. Furthermore, matrix metalloproteinase (MMP)-2 and -9 were decreased in the podocyte injury group, which was inhibited by different concentrations of AST. Thus, AST was able to maintain the balance of oxidative stress in podocytes cultured with ADR and protect them from ADR-induced injury. The mechanism may be associated with the upregulation of MMPs.