LAUSR

OBJECTIVE In recent years, the roles of Neuregulin-1 (NRG-1) in optic nerve injury and retinal cells have been investigated. However, the molecular mechanism by which NRG-1 affects optic nerve injury remains elusive and merits deeper exploration. Hence, this study examined the specific function of NRG-1 in the RhoA/cofilin/F-actin axis in optic nerve injury. METHODS Retinal cells were isolated and identified for subsequent experimental uses. Reverse transcription quantitative polymerase chain reaction and Western blot assays were performed to measure NRG-1 expression in retinal cells which were cultured under elevated pressure. TUNEL staining was used to detect the cell apoptosis rate, and Western blot assay was performed to detect the expression of related genes. The axon growth was examined by immunofluorescence. The effects of NRG-1 on RhoA activity, cofilin phosphorylation, and F-actin were detected by Western blot assay. In other studies we established a rat model of acute optic nerve injury, and tested for beneficial effects of NRG-1 in vivo. RESULTS High expression of NRG-1 was evident in the retinal tissues of rats with optic nerve injury. Overexpressing NRG-1 successfully inhibited RhoA activity and the phosphorylation of cofilin and promoted F-actin expression. In cell experiments, overexpressed NRG-1 suppressed the apoptosis of retinal cells and promoted axon growth through the RhoA/cofilin/F-actin axis. In animal experiments, overexpressed NRG-1 relieved retinal injury. CONCLUSION Our results strongly suggest that overexpressed NRG-1 is highly effective in the protection of normal optic nerve function by suppressing RhoA activity and the phosphorylation of cofilin and rescuing F-actin function.