Infection with adenovirus-mediated luciferase reporter gene in mesenchymal stem cells and bioluminescence imaging / 中华核医学与分子影像杂志

ABSTRACT

Objective To construct adenovirus vector containing firefly luciferase reporter gene (AdLuc) and infect bone marrow mesenchymal stem cells (BMSC),then to take bioluminescence imaging in vitro and in vivo for identification.Methods The luciferase gene was amplified with PCR from psiCHECK-2 plasmid and cloned into the adenoviral shuttle vector (pShuttle-CMV).It was confirmed by Nhe Ⅰ/Xba Ⅰ digestion and sequencing.PShuttle-CMV-Luc and backbone vector (pAdeno) were homologous recombined.Then the recombinant plasmid was packaged in HEK293 cells and the virus titer was detected.The BMSC were infected by the recombinant adenovirus.The bioluminescence imaging in vitro was performed to determine the best multiplicity of infection (MOI),and the relationship between bioluminescence intensity and MOI was analyzed by curve fitting regression analysis.Viability was evaluated via Trypan blue staining.The transfected BMSC (l× 106) were implanted into the muscles of forelimb of SD rats,and then tracked by bioluminescence imaging in vivo.Cell viability was compared using two-way repeated measures analysis of variance between groups.Results Enzyme digestion and sequence analysis indicated that Ad-Luc was successfully constructed.The virus titer was 1 × 1010 plaque forming unit (PFU)/ml.The bioluminescence detection in vitro showed that Ad-Luc could infect BMSC high efficiently to express luciferase and the best MOI was 50.The bioluminescence intensity enhanced with increase of MOI (R2 =0.98).No statistically significant difference was found in cell viability between transfected and untransfected BMSC at 1,3,5,7 d.The cell survival rates were (92.5±2.3)％ vs (94.1±1.8)％,(91.4±0.9)％ vs (92.7±2.0)％,(92.1±1.6)％ vs (93.3± 2.4) ％,(91.9 ± 1.5) ％ vs (93.0 ± 3.1) ％,respectively (F =4.38,P ＞ 0.05).The bioluminescence imaging in vivo showed that BMSC survived 1,3,7 d after implantation.However,bioluminescence signal decreased gradually over time.Conclusion It is feasible to apply the optical reporter gene imaging for tracing transplanted stem cells in vitro and in vivo due to the effective transformation of luciferase reporter gene into BMSC by adenovirus vector.