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Published on: July 7, 2017
CpG-free plasmids confer reduced inflammation and sustained pulmonary gene expression
Stephen C Hyde1, Ian A Pringle, Syahril Abdullah
1Gene Medicine Research Group, Nuffield Department of Clinical Laboratory Sciences, University of Oxford, Oxford OX3 9DU, UK. steve.hyde@ndcls.ox.ac.uk
Nature Biotechnology
|April 29, 2008
Summary
Removing CpG sequences from plasmid DNA (pDNA) prevents lung inflammation and prolongs gene expression after pulmonary delivery. CpG-free pDNA enables sustained in vivo transgene expression without triggering an immune response.
Area of Science:
- Molecular biology
- Gene therapy
- Immunology
Background:
- Pulmonary delivery of plasmid DNA (pDNA) with cationic liposomes often causes inflammation due to unmethylated CG dinucleotides (CpG).
- This CpG-mediated inflammation leads to a short duration of transgene expression.
- The presence of even a single CpG in pDNA can trigger this inflammatory response.
Purpose of the Study:
- To investigate the role of CpG sequences in pDNA-induced pulmonary inflammation.
- To develop CpG-free pDNA vectors for sustained in vivo transgene expression.
- To assess the impact of CpG removal on the duration of gene expression and inflammatory responses in the lungs.
Main Methods:
- Construction and evaluation of CpG-free pDNA expression vectors.
- Pulmonary delivery of pDNA/cationic liposome complexes in vivo.
- Assessment of transgene expression levels and duration.
- Analysis of lung inflammatory responses.
Main Results:
- Retention of a single CpG in pDNA was sufficient to elicit an acute inflammatory response.
- CpG-free pDNA vectors did not induce lung inflammation.
- Sustained in vivo transgene expression (>=56 days) was achieved using CpG-free pDNA vectors.
- Pulmonary delivery of CpG-free pDNA resulted in prolonged gene expression without inflammation.
Conclusions:
- CpG sequences in pDNA are the primary cause of acute lung inflammation following pulmonary delivery.
- CpG-free pDNA vectors are a viable strategy for achieving sustained transgene expression.
- Eliminating CpG motifs offers a promising approach to enhance the safety and efficacy of pulmonary gene therapy.
