Construction of a stable mouse fibroblast line targeting mammalian target of rapamycin by lentivirus mediated short hairpin RNA / 中华实验眼科杂志

ABSTRACT

Background Age-related macular degeneration (AMD) is a group of vision-threatening eye disorders.Previous researches showed that the activation of Akt/mammalian target of rapamycin (Akt/mTOR) pathway closely related to the mechanism of AMD.A new specific method to inhibit Akt/mTOR pathway will become a breakthrough for the treatment of AMD.Objective This study was to establish a mouse fibroblast cell line (NIH/3T3) which can stably inhibit the expression of mTOR gene and provide a cell model for the study on the function of Akt/mTOR pathway in AMD and observe the influence of mTOR gene knockdown on related proteins.Methods Three short hairpin RNAs (shRNAs) targeting mTOR gene were designed and synthesized based on murine mTOR mRNA sequence.Double-strand shRNA hairpins were separately cloned into PIGZ-green fluorescent protein (GFP) +Puro vectors to produce recombination plasmids.The packaged lentiviral plasmids and RNAi plasmids were co-transfected into NIH/3T3 cells,a mouse fibroblast line.After puromycin selection and culture expansion,0.5 mg/L puromycin was added the culture medium to establish stable cell clones.The expressions of mTOR mRNA and protein in NIH/3T3 cells were detected by real-time PCR and Western blot respectively,and the inhibitory efficiency of interference was analyzed.Results Transfected GFP-labeled NIH/3T3 cells by lentiviral presented the green fluoresccence with the efficiency of infection of 90％ in the third day.Real-time PCR showed a distinct band of mTOR mRNA in 184 bp.The knockdown rate for sh1,sh2 and sh3 were respectively 31.3％,31.8％ and 45.3％ in the lower multipolicity of infection (MOI) group ;while in the higher MOI group,the knockdown rate for sh1,sh2 and sh3 were 47.1％,56.5％ and 71.6％ respectively.Western blot assay exhibited weakened expression band of mTOR protein in NIH/3T3 cell line for sh1,sh2 and sh3 in both lower and higher MOI groups with the weakest expression for sh3.Conclusions A stable mouse fibroblast cell line is established by the inhibition of mTOR with RNA interference technique,which can provide a cell model for studying the function of Akt/mTOR pathway in AMD.