Bioluminescence imaging after HSV amplicon vector delivery into brain.

Area of Science:

• Molecular Biology
• Neuroscience
• Biotechnology

Background:

• Firefly luciferase (Fluc) is a standard reporter for gene expression analysis.
• Traditional methods require luminometers and are not suitable for live animal studies.
• Digital imaging offers a non-invasive alternative for measuring luciferase activity in vivo.

Purpose of the Study:

• To develop and validate a herpes simplex virus (HSV) amplicon vector system for non-invasive gene expression monitoring in live animals.
• To assess the feasibility of using bioluminescence imaging (BLI) for semi-quantitative analysis of Fluc expression in the mouse brain.

Main Methods:

• An HSV amplicon vector encoding Fluc cDNA was constructed with either a viral or inducible promoter.
• Vectors were delivered to cultured cells and stereotactically injected into the mouse brain.
• Fluc expression was measured using biochemical assays, Western blots, luminometry, and non-invasive BLI.

Main Results:

• HSV amplicon vectors demonstrated dose-dependent Fluc expression in cultured cells upon induction.
• Non-invasive BLI detected robust Fluc activity in the mouse cortex for up to one week post-injection with a viral promoter.
• Inducible promoter-driven Fluc expression was detectable for up to five days, with no signal in the uninduced state.

Conclusions:

• HSV amplicon vectors facilitate rapid, non-invasive, and semi-quantitative gene expression analysis in the brain.
• This system provides a valuable tool for longitudinal studies of gene expression in vivo.