Previous Article | Next Article ![]()
Journal of Virology, January 1999, p. 519-532, Vol. 73, No. 1
Department of Molecular Genetics and
Biochemistry,1
Western Psychiatric
Institute and Clinic,2 and
Department of Neurology,3 University of
Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, and
Veterans Administration Medical Center, Pittsburgh,
Pennsylvania 152404
Received 29 June 1998/Accepted 2 September 1998
Nerve growth factor
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Herpes Simplex Virus Type 1 Vector-Mediated Expression of Nerve
Growth Factor Protects Dorsal Root Ganglion Neurons from
Peroxide Toxicity
subunit (
-NGF) transgene delivery and
expression by herpes simplex virus type 1 (HSV-1) vectors was examined
in a cell culture model of neuroprotection from hydrogen peroxide
toxicity. Replication-competent (tk
K mutant background)
and replication-defective (ICP4
;tk
S mutant
background) vectors were engineered to contain the murine
-NGF cDNA
under transcriptional control of either the human cytomegalovirus immediate-early gene promoter (HCMV IEp) (e.g., KHN and SHN) or the
latency-active promoter 2 (LAP2) (e.g., KLN and SLN) within the
viral thymidine kinase (tk) locus. Infection of rat B103 and mouse N2A
neuronal cell lines, 9L rat glioma cells, and Vero cells with the KHN
or SHN vectors resulted in the production of
-NGF-specific transcripts and
-NGF protein reaching a maximum at 3 days
postinfection (p.i.). NGF protein was released into the culture media
in amounts ranging from 10.83 to 352.86 ng/ml, with the highest levels
being achieved in B103 cells, and was capable of inducing neurite
sprouting of PC-12 cells. The same vectors produced high levels of NGF
in primary dorsal root ganglion (DRG) cultures at 3 days. In contrast to HCMV IEp-mediated expression, the LAP2-NGF vectors showed robust expression in primary DRG neurons at 14 days. The neuroprotective effect of vector produced NGF was assessed by its ability to inhibit hydrogen peroxide-induced neuron toxicity in primary DRG cultures. Consistent with the kinetics of vector-mediated NGF expression, HCMV-NGF vectors were effective in abrogating the toxic effects of
peroxide at 3 but not 14 days p.i. whereas LAP2-NGF vector transduction
inhibited apoptosis in DRG neurons at 14 days p.i. but was ineffective
at 3 days p.i. Similar kinetics of NGF expression were observed with
the KHN and KLN vectors in latently infected mouse trigeminal ganglia,
where high levels of
-NGF protein expression were detected at 4 wks
p.i. only from the LAP2; HCMV-NGF-driven expression peaked at 3 days
but could not be detected during HSV latency at 4 weeks. Together,
these results indicate that (i) NGF vector-infected cells produce and
secrete mature, biologically active
-NGF; (ii) vector-synthesized
NGF was capable of blocking peroxide-induced apoptosis in primary DRG
cultures; and (iii) the HCMV-IEp functioned to produce high levels of
NGF for several days; but (iv) only the native LAP2 was capable of
long-term expression of a therapeutic gene product in latently infected
neurons in vivo.
*
Corresponding author. Mailing address: Department of
Molecular Genetics and Biochemistry, University of Pittsburgh School of
Medicine, E1240 Biomedical Science Tower, Pittsburgh, PA 15261. Phone:
(412) 648-8106. Fax: (412) 624-8997. E-mail:
joe{at}hoffman.mgen.pitt.edu.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|