Long-term increases in neurotransmitter release from neuronal cells expressing a constitutively active adenylate cyclase from a herpes simplex virus type 1 vector.

Abstract

Signal-transduction pathways mediate a wide range of short-term changes in the physiology of neuronal systems from invertebrates to mammals. However, examples of long-term changes in neuronal physiology mediated by these pathways have been limited to invertebrate systems. In this report, long-term changes in the physiology of mammalian neurons were studied by using genetic intervention to cause a long-lasting activation of the cAMP pathway. The Signal-transduction pathways are known to mediate shortterm changes in mammalian neuronal function by modulating the activities of specific neurotransmitter (NT) receptors, voltage-gated ion channels, and components of the NTrelease machinery (1,2). In invertebrates, these same pathways mediate both short-term and long-term changes in nervous system function (3, 4). Thus, signal-transduction pathways may also mediate the changes in mammalian neuronal physiology that are responsible for long-term alterations in the strengths of synaptic connections.The cAMP pathway mediates both short-term and longterm changes in invertebrate nervous system function associated with certain behavioral adaptations (4). Short-term changes include presynaptic facilitation of the gill withdrawal reflex in Aplysia, wherein a stimulus activates the cAMP pathway, which enhances NT release (3). The role of the cAMP pathway in mediating long-term changes in invertebrate nervous system function is illustrated by a mutation in a cAMP phosphodiesterase, dunce, that affects associative learning in Drosophila (4). The capability of the cAMP pathway to mediate long-term changes in invertebrate neuronal physiology suggests that this same pathway might function similarly in mammalian neuronal physiology.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Signal-transduction pathways, including the cAMP pathway, mediate a wide range of short-term changes in mammalian neuronal physiology (1, 2). Substantial evidence supports the involvement of these pathways in mediating or modulating NT release (5, 6). In particular, the cAMP pathway can affect short-term changes in NT release from many neuronal cell types, including PC-12 cells and sympathetic, striatal, and cortical neurons (7-9). Most effects of the cAMP pathway are mediated by protein kinase A (PKA)-dependent phosphorylation, which can modulate the activity of specific NT receptors, voltage-gated ion channels, cytoskeletal proteins, NT-synthesizing enzymes, synaptic vesicle proteins, and other neuronal proteins (1,2).The evidence that signal-transduction pathways effect long-lasting changes in mammalian neuronal function is less direct. Transcription of specific neuronal genes can be regulated by the cAMP and other signal-transduction pathways (10). Physiological activity (action potentials) can elicit a complex transcriptional response mediated by c-fos and c-jun (10). The stable maintenan...

High efficiency gene transfer to the central nervous system of rodents and primates using herpes virus vectors lacking functional ICP27 and ICP34.5

“…23 Discussion HSV-based vectors have been shown in a number of studies to be capable of expressing either a marker gene 9,17,21 or a gene of potential therapeutic benefit. 11,[24][25][26][27][28] Thus, for example, the expression of nerve growth factor using such a vector was shown to prevent the cell death which normally occurs in sympathetic ganglia following axotomy. 24 Similarly the expression of tyrosine hydroxylase in this manner can relieve the abnormal rotational behaviour observed in the 6-hydroxidopamine rodent model of Parkinson's disease.…”

Functional measurements of [Ca2+] in the endoplasmic reticulum using a herpes virus to deliver targeted aequorin

“…The pHSVerAEQ plasmid vector is shown schematically in Figure 1B. The erAEQ chimeric construct is cloned in the EcoRI site into the pHSVpuc amplicon [20] under the control of the HSV-1 IE (immediate early gene) 4/5 promoter and then packaged into virus particles as outlined in Materials and methods.…”

“…The erAEQmut cDNA was isolated from the original vector by EcoRI digestion and cloned into the recipient vector pHSVpuc [20] to generate the pHSVerAEQ. The pHSVlac amplicon vector which expresses the P-galactosidase gene of Escheridzia coli has been described previously [2 11.…”

In vivo expression of therapeutic human genes for dopamine production in the caudates of MPTP-treated monkeys using an AAV vector

“…In contrast, the bicistronic construct released both L-Dopa (800 pg/h/10 6 cells) and dopamine (4050 pg/h/10 6 cells) into the medium, measured as previously described. 13 In AAVflag⌬thIRESaadc-transfected but not mock-transfected or AAVlac-transfected cells, numerous FLAG-IR cells were detected using immunocytochemistry with a FLAG antibody (Figure 1). In vivo studies in primates provide means to study vector and gene expression directly in model systems that closely resemble clinical Parkinson's disease.…”

“…Samples of the medium were taken at both 30 min and 60 min and catecholamines analyzed using a coulometric electrode array series HPLC as previously described. 13 …”