Efficiency of targeted interference on early growth response factor-1 by lentivirus vector containing shRNA transfected into mouse retina

Objective To construct the lentivirus vector containing green fluorescent protein (GFP)and early growth response factor-1 short hairpin RNA(Egr-1 shRNA),and to determine the efficiency of interference on Egr-1 gene in lentivirus vector-transfected mouse retinal tissue.Methods Based on the target sequences of Egr-1 shRNA screened and identified previously,the LV-shRNA(Egr-1)containing GFP and Egr-1 shRNA Was constructed.Twenty 15-day-old C57BL/6 mice were randomly divided into experimental group and negative control group(n=10 each).LV-shRNA(Egr-1)lentivirus vector Was transfected into the right eyes in the experimental group with intravitreal injection.LV-NC lentivirus vector that did not target at any specific gene Was also transfected into the right eyes in the negative control group,while the left eyes were untreated in both two groups as the blank control group.After 2 weeks,the transfection of lentiviral vector was examined under fluorescence microscope.Moreover,real-time quantitative polymerase chain reaction (RQ-PCR), Western blot and immunofluorescence were used to detect the expression of Egr-1 gene for evaluation of the interference efficiency. Results After lentiviral vector was intravitreally injected and transfected into the mouse retinal tissue, GFP was found to be widely distributed in the whole layer of the retina including the retinal pigment epithelium. RQPCR showed significantly down-regulated expression of Egr-1 mRNA in the injected eyes of experimental group compared with blank or negative controls (0.290±0.074 vs 1.006±0.033, 1.010± 0.086, all P＜0.001) , with the inhibition rate being 71.29%. Western blot demonstrated that the expression of Egr-1 protein was remarkably down-regulated in the injected eyes of experimental group (0.224±0.035 vs 0.674±0.050, 0.688±0.049, all P＜0.00l) , with the inhibition rate being 67.44%. Furthermore, immunofluorescence revealed no expression of fluorescence protein, except sparse distribution of Egr-1 positive cells in the inner nuclear layer of injected eyes of the experimental group. Conclusions The lentivirus vector containing GFP and Egr-1 shRNA is successfully constructed, and it may have high transfection efficiency and a wide distribution in the intravitreally injected mice eyes. Furthermore, the lentivirus vector has a high inhibition efficiency of Egr-1 gene in the mouse retina. Key words: Early growth response factor-1;  RNA interference;  Transfection;  Lentivirus vector;  Gene expression regulation