Effects of defective herpes simplex vectors expressing neurotrophic factors on the proliferation and differentiation of nervous cells in vivo

Abstract

Neurotrophic factors (NTFs) are known to govern the processes involved in central nervous system cell proliferation and differentiation. Thus, they represent very attractive candidates for use in the study and therapy of neurological disorders. We constructed recombinant herpesvirus-basedvectors capable of expressing fibroblast growth factor-2 (FGF-2) and ciliary neurotrophic factor (CNTF) alone or in combinations. In vitro, vectors expressing FGF-2 and CNTF together, but not those expressing either NTF alone, caused proliferation of O-2A progenitors. Furthermore, based on double-labeling experiments performed using markers for neurons (MAP-2), oligodendrocytes (CNPase) and astrocytes (GFAP), most of the new cells were identified as astrocytes, but many expressed neuronal or oligodendrocytic markers. In vivo, vectors have been injected in the rat hippocampus. At 1 month after inoculation, a highly significant increase in BrdU-positive cells was observed in the dentate gyrus of animals injected with the vector expressing FGF-2 and CNTF together, but not in those injected with vectors expressing the single NTFs. Furthermore, double-labeling experiments confirmed in vitro data, that is, most of the new cells identified as astrocytes, some as neurons or oligodendrocytes. These data show the feasibility of the vector approach to induce proliferation and differentiation of neurons and/or oligodendrocytes in vivo. Gene Therapy (2005) 12, 559-569.

Localized delivery of fibroblast growth factor–2 and brain-derived neurotrophic factor reduces spontaneous seizures in an epilepsy model

“…The double mutant (TH-FGF2/0-BDNF) was obtained by crossing over TH-FGF2 and T0-BDNF. Promoters were chosen to promote a synergy between the NTFs, making use first of the FGF-2 property of potently inducing proliferation of hippocampal progenitors and then of the BDNF property of inducing their neuronal differentiation: the HCMV IE promoter driving FGF-2 is known to ensure robust, but transient, transgene expression, whereas the ICP0 promoter driving BDNF provides a longer-lasting expression (14).…”

FGF-2 Overexpression Increases Excitability and Seizure Susceptibility but Decreases Seizure-Induced Cell Loss

“…The immunohistochemistry protocol was based on a previously described one (Marconi et al, 1999(Marconi et al, , 2005. Briefly, sections were deparaffinized (2 washes in xylol 10 min, 5 min in ethanol 100%, 5 min in ethanol 95%) and then rehydratated in distilled water for 5 min and in PBS 1ϫ for 10 min.…”

“…BrdU immunostaining was performed as previously described (Marconi et al, 2005). Briefly, DNA was denatured by incubating tissue sections in 2 N HCl for 30 min at 37°C.…”

HSV as a vector in vaccine development and gene therapy

“…156 Experimental evidence indicates that treatment with multiple neurotrophic factors can significantly increase motor neuron survival in comparison with the delivery of a single factor alone. 157,158 HSV-1 vectors that have been engineered to express multiple neurotrophic factors have been used to deliver these molecules to specific neuron populations. 159 Non-replicative vectors containing basic fibroblast growth factor (bFGF), ciliary neurotrophic factor (CNTF) and EGFP (as a reporter gene) have already been shown to induce proliferation and differentiation in O-2A oligospheres obtained from newborn rat brains in vitro and also in the rat hippocampus in vivo.…”