Effects of FoxO1 on podocyte injury in diabetic rats

• The structures and functions of podocytes were impaired in STZ-induced diabetic rats.
• Constitutively active FoxO1 ameliorates structure injury and preserves function of podocytes in diabetic rats.
• FoxO1 may alleviate the pathological changes associated with diabetic nephropathy.

ObjectiveThis study was designed to investigate the protective effect of forkhead transcription factor O1 (FoxO1) on podocyte injury in rats with diabetic nephropathy.MethodsStreptozotocin-induced diabetic rats were served as DM group, while DM rats transfected with blank lentiviral vectors (LV-pSC-GFP) or lentiviral vectors carrying constitutively active FoxO1 (LV-CA-FoxO1) were served as LV-NC group or LV-CA group, respectively. The control group (NG) consisted of uninduced rats that received an injection of diluent buffer. At 2, 4, and 8 weeks after transfection, the levels of urine albumin, blood glucose, blood urea nitrogen, serum creatinine and urine podocalyxin were measured. Real-time PCR and western blotting were performed to measure mRNA and protein levels of FoxO1, podocalyxin, nephrin, and desmin in renal cortex. In addition, light and electron microscopy were used to detect structural changes in the glomerulus and podocytes.ResultsCompared with the rats in LV-NC and DM groups, LV-CA rats showed a significant increase in FoxO1 mRNA and protein levels and a distinct decrease in urine albumin, blood urea nitrogen, and serum creatinine (except at the two-week time point) levels (p < 0.05). Podocalyxin and nephrin mRNA and protein levels increased (p < 0.05), whereas desmin mRNA and protein levels decreased (p < 0.05). Pathological changes in glomerulus were also ameliorated in LV-CA group.ConclusionsUpregulating expression of FoxO1 by transduction with recombinant lentivirus ameliorates podocyte injury in diabetic rats.