Potential role of microRNA-503 in Icariin-mediated prevention of high glucose-induced endoplasmic reticulum stress

BACKGROUND Dysregulated microRNA(miRNA)is crucial in the progression of diabetic nephropathy(DN).AIM To investigate the potential molecular mechanism of Icariin(ICA)in regulating endoplasmic reticulum(ER)stress-mediated apoptosis in high glucose(HG)-induced primary rat kidney cells(PRKs),with emphasis on the role of miR-503 and sirtuin 4(SIRT4)in this process.METHODS Single intraperitoneal injection of streptozotocin(65 mg/kg)in Sprague-Dawley rats induce DN in the in vivo hyperglycemic model.Glucose-treated PRKs were used as an in vitro HG model.An immunofluorescence assay identified isolated PRKs.Cell Counting Kit-8 and flow cytometry analyzed the effect of ICA treatment on cell viability and apoptosis,respectively.Real-time quantitative polymerase chain reaction and western blot analyzed the levels of ER stressrelated proteins.Dual luciferase analysis of miR-503 binding to downstream SIRT4 was performed.RESULTS ICA treatment alleviated the upregulated miR-503 expression in vivo(DN)and in vitro(HG).Mechanistically,ICA reduced HG-induced miR-503 overexpression,thereby counteracting its function in downregulating SIRT4 levels.ICA regulated the miR-503/SIRT4 axis and subsequent ER stress to alleviate HG-induced PRKs injury.CONCLUSION ICA reduced HG-mediated inhibition of cell viability,promotion of apoptosis,and ER stress in PRKs.These effects involved regulation of the miR-503/SIRT4 axis.These findings indicate the potential of ICA to treat DN,and implicate miR-503 as a viable target for therapeutic interventions in DN.