Overexpression of Basic Fibroblast Growth Factor and Bcl-xL with Adenoviral Vectors Protects Primarily Cultured Neurons against Glutamate Insult

Abstract

Excitatory amino acid (EAA) toxicity seems to be an important mechanism of neuronal cell death after cerebral infarction. We examined the inhibitory effects of neuronal cell death caused by EAA in vitro by means of adenoviral gene transfer of neurotrophic basic fibroblast growth factor (bFGF) and antiapoptotic Bcl-xL. Recombinant adenoviral vectors expressing human bFGF gene with secretory signals of interleukin-2 and human Bcl-xL gene were constructed. Primarily cultured rat neuronal cells were treated with glutamate to cause EAA, and the neuroprotective effects of gene transfer by these adenoviral vectors were investigated at several time points of infection. Each adenoviral infection to primarily cultured neuronal cells exhibited neuroprotective effects against EAA caused by glutamate. Both gene transfer of bFGF with secretory signal and Bcl-xL transfer to neuronal cells exhibited the synergistic neuroprotective effects against EAA. These effects were most prominent with gene transfer 4 hours before glutamate insult; gene transfer performed simultaneously with and up to 4 hours after the insult exhibited definite neuroprotective effects. These experiments revealed marked neuroprotective effects of adenoviral gene transfer of bFGF and Bcl-xL into neuronal cells in vitro. The findings may lead to new approaches for treating occlusive cerebrovascular disease.