Generation of light-producing somatic-transgenic mice using adeno-associated virus vectors
We have previously designed a library of lentiviral vectors to generate somatic-transgenic rodents to monitor signalling pathways in diseased organs using whole-body bioluminescence imaging, in conscious, freely moving rodents. We have now expanded this technology to adeno-associated viral vectors. We first explored bio-distribution by assessing GFP expression after neonatal intravenous delivery of AAV8. We observed widespread gene expression in, central and peripheral nervous system, liver, kidney and skeletal muscle. Next, we selected a constitutive SFFV promoter and NF{kappa}B binding sequence for bioluminescence and biosensor evaluation.\n\nAn intravenous injection of AAV8 containing firefly luciferase and eGFP under transcriptional control of either element resulted in strong and persistent widespread luciferase expression. A single dose of LPS-induced a 10-fold increase in luciferase expression in AAV8-NF{kappa}B mice and immunohistochemistry revealed GFP expression in cells of astrocytic and neuronal morphology. Importantly, whole-body bioluminescence persisted up to 240 days.\n\nTo further restrict biosensor activity to the CNS, we performed intracerebroventricular injection of each vector. We observed greater restriction of bioluminescence to the head and spine with both vectors. Immunohistochemistry revealed strongest expression in cells of neuronal morphology. LPS administration stimulated a 4-fold increase over baseline bioluminescence.\n\nWe have validated a novel biosensor technology in an AAV system by using an NF{kappa}B response element and revealed its potential to monitor signalling pathway in a non-invasive manner using a model of LPS-induced inflammation. This technology employs the 3Rs of biomedical animal research, complements existing germline-transgenic models and may be applicable to other rodent disease models with the use of different response elements.