AIM: To observe the effect of myocyte enhancer factor 2C (MEF2C) on the expression of substance P (Sub P) and neurofilament triplet L (NFL) in rat dorsal root ganglion cells (DRGn cells). METHODS: DRG neurons were dissociated and cultured, and then exposed to different concentrations of nerve growth factor (NGF, 10 μg/L, 30 μg/L, 100 μg/L or 200 μg/L) for 24 h. The neurons cultured in media with the lowest concentration of NGF (10 μg/L) served as control. Real time PCR was used for detecting the mRNA of substance P and NFL in the DRGn cells. Three MEF2C-siRNAs were transfected into PC 12 cell line by the way of chemical mediation. The best siRNA with the highest interference ratio was determined by real time PCR. The DRGn cells knocked out MEF2C gene were also transfected with siRNA, and the expressions of substance P and NFL were measured by real time PCR after stimulated with high concentration of NGF. RESULTS: The expressions of substance P and NFL increased in primary cultured rat DRG neurons in a dose-dependent manner of NGF stimulation. The expression level of MEF2C in experimental group was lower by 50% than that in control group. No change of cyclic AMP response element-binding protein (CREB) was observed. The substance P decreased by 41% in experimental group than that in control group at the same time point. The NFL was decreased by 61%. CONCLUSION: NGF may promote the synthesis of substance P and NFL in rat DRGn cells. MEF2C regulates the expression of substance P and NFL in DRGn cells in rat embryo and MEF2C may be a critical transcriptional factor involved in the airway hyperresponsiveness.

OBJECTIVE: To explore the effect of nerve growth factor(NGF) and interferon regulatory factor-1(IRF-1) on sodium current change of sensory neuron in rat pheochromocytoma cells. METHODS: Sensory neuron rat pheochromocytoma cells were stimulated by different concentrations of NGF(0-200 ng/mL), the IRF-1 mRNA levels were examined by real-time PCR, and the activation of IRF-1 was examined by Western blot. The sodium current change was recorded by patch clamp. RESULTS: Low concentration of NGF improved the sodium current, which was concentration dependent. When exposed to high concentration of NGF, the expression of IRF-1 mRNA in PC-12 was improved. Low concentration of NGF resulted in IRF-1 intronuclear transporting, and the expression was not affected. Sodium current did not occur in PC-12 cells when IRF-1 was blocked. CONCLUSION NGF can improve the sodium current in PC-12 cells concentration-dependently, and the improvement is regulated by IRF-1.
Animals ; Interferon Regulatory Factor-1 ; genetics ; metabolism ; Nerve Growth Factor ; pharmacology ; PC12 Cells ; RNA, Messenger ; genetics ; metabolism ; Rats ; Real-Time Polymerase Chain Reaction ; Sodium Channels ; drug effects