Article
EIAV- and HIV-based lentiviral vectors for corneal gene therapy: Evaluation of an E-Selectin-inducible promoter system
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Published: | September 22, 2004 |
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Outline
Text
Objective
In this report, the ability of self-inactivating (U3 deleted long terminal repeat (LTR)) HIV-1 and EIAV-based vectors to mediate gene transfer to rabbit and human corneas and a murine corneal endothelial cell line is determined. For specificity of action the heterologous promoter in the vector was exchanged for an inducible E-Selectin promoter, previously shown to regulate gene-expression in a plasmid system.
Methods
All vectors were pseudotyped with a vesicular stomatitis virus-G (VSV-G) envelope and contained marker transgenes under the control of an internal CMV promoter. In the case of EIAV the internal promoter was cleaved and replaced by an inducible E-Selectin promoter. For safety issues the long terminal repeats within the virus genome were partially deleted.
Results
We show for the first time that EIAV is more efficient than HIV in transducing corneal cells. However, in the case of the inducible EIAV vector, we detected impairment between the vector and its internal E-Selectin promoter. Instead of controlled transgene expression or silencing of promoter activity, also known as LTR-interference, the U3-modified LTR impaired the conditional activity of the E-Selectin promoter. A significant transgene expression was seen in the un-induced state.
Conclusions
The authors show that EIAV-based lentiviruses are superior HIV-1 based lentivirues in terms of gene-transfer to full-thickness human or rabbit corneas or a corneal endothelial cell line. The modification within the U3-LTR did not adequately allow regulated transgene expression. These findings have important implications for vector design for diagnostic or therapeutic opportunities.
Acknowledgement
SCB was supported by Gertrud-Kusen-Stiftung, Hamburg, Germany. AJTG is a BBSRC Research Leave Fellow. All viruses used for this work were a kind gift of Oxford Biomedica, UK.