Hippocampal infection with HSV‐1‐derived vectors expressing an NMDAR1 antisense modifies behavior

Abstract

Herpes simplex virus-derived amplicon vectors simultaneously expressing the open reading frame encoding NR1 subunit of the NMDA receptor, either in sense or antisense orientation, as well as the open reading frame encoding the green fluorescent protein (GFP), as distinct transcription units, were constructed. Vector expression in cells was demonstrated by GFP-fluorescence, immunofluorescence, Western blots and RT-PCR. The vectors were inoculated into the dorsal hippocampus of adult male rats, which were then trained for habituation to an open field and for inhibitory avoidance to a foot-shock. Those animals injected with vectors expressing NR1 protein showed habituation to a new environment, and achieved the criteria for a step-down inhibitory avoidance to a foot-shock. In contrast, animals injected with vectors carrying the NR1 open reading frame in antisense position, showed neither habituation nor appropriate performance in the inhibitory avoidance task. There was no evidence for motor impairment or motivational disturbance, since all the animals exhibit similar behavior and performance in the training sessions. Hence, the impaired performance might be due to either amnesia or disability to record events. Transgene expression in brain, as revealed by GFP fluorescence, was mainly observed in pyramidal cells of CA1, but also in CA3. Therefore, our results strongly support the participation of hippocampal NR1 subunit in habituation to a new environment, but also in recording events for the inhibitory avoidance task. Hence, amplicon vectors appear to be useful tools to modify endogenous gene expression at a defined period, in restricted brain regions, and should allow investigating in vivo functions of genes.

Intrauterine growth restriction due to uteroplacental insufficiency decreased white matter and altered NMDAR subunit composition in juvenile rat hippocampi

“…hippocampal NR1 correlates with impaired spatial learning (1), and partial knockdown of NR1 resulted in impaired memory (13) and behavior (3) even when only 6 -7% of neurons were affected (3).…”

Identification of transmitter systems and learning tag molecules involved in behavioral tagging during memory formation

“…Based on the prominent role of NMDA receptors during the encoding of different hippocampus-dependent learning tasks, including IA (11,(15)(16)(17), we studied whether NMDA receptors in the dHP are involved in the setting of the IA learning tag. Our results show that although control animals expressed IA-LTM (P < 0.001), infusion of D-2-amino-5-phosphono pentanoate (AP-5) into the CA1 region 10 min before sIA training induced an amnesic effect in animals tested 24 h later; furthermore, this effect was not prevented by the exposure to a novel OF 1 h before the sIA training (Fig.…”

HSV as a vector in vaccine development and gene therapy

“…Amplicons expressing genes affecting neurotransmitter expression or neuroreceptor synthesis have been used to study behavioral features, like learning and memory. [131][132][133][134] Amplicons have also been used to deliver tyrosine hydroxylase and other genes to the nigro-striatal system or to cultured striatal cells, in studies aimed to treat Parkinson's disease. [135][136][137][138][139] More recently, amplicons were shown to be able to deliver genes to the retinal pigment epithelial cells of the rat retina, but not to the adjacent photoreceptors.…”