Coexpression of tyrosine hydroxylase, GTP cyclohydrolase I, aromatic amino acid decarboxylase, and vesicular monoamine transporter 2 from a helper virus-free herpes simplex virus type 1 vector supports high-level, long-term biochemical and behavioral correction of a rat model of Parkinson's disease.
Parkinson's disease is due to the selective loss of nigrostriatal dopaminergic neurons. Consequently, many therapeutic strategies have focused on restoring striatal dopamine levels, including direct gene transfer to striatal cells, using viral vectors that express specific dopamine biosynthetic enzymes. The central hypothesis of this study is that coexpression of four dopamine biosynthetic and transporter genes in striatal neurons can support the efficient production and regulated, vesicular release of dopamine: tyrosine hydroxylase (TH) converts tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA), GTP cyclohydrolase I (GTP CH I) is the rate-limiting enzyme in the biosynthesis of the cofactor for TH, aromatic amino acid decarboxylase (AADC) converts L-DOPA to dopamine, and a vesicular monoamine transporter (VMAT-2) transports dopamine into synaptic vesicles, thereby supporting regulated, vesicular release of dopamine and relieving feedback inhibition of TH by dopamine. Helper virus-free herpes simplex virus type 1 vectors that coexpress the three dopamine biosynthetic enzymes (TH, GTP CH I, and AADC; 3-gene-vector) or these three dopamine biosynthetic enzymes and the vesicular monoamine transporter (TH, GTP CH I, AADC, and VMAT-2; 4-gene-vector) were compared. Both vectors supported production of dopamine in cultured fibroblasts. These vectors were microinjected into the striatum of 6-hydroxydopamine-lesioned rats. These vectors carry a modified neurofilament gene promoter, and gamma-aminobutyric acid (GABA)-ergic neuron-specific gene expression was maintained for 14 months after gene transfer. The 4-gene-vector supported higher levels of correction of apomorphine-induced rotational behavior than did the 3-gene-vector, and this correction was maintained for 6 months. Proximal to the injection sites, the 4-gene-vector, but not the 3-gene-vector, supported extracellular levels of dopamine and dihydroxyphenylacetic acid (DOPAC) that were similar to those observed in normal rats, and only the 4-gene-vector supported significant K(+)-dependent release of dopamine.
Sun
Mei
M
Department of Neurology, West Roxbury VA Hospital/Harvard Medical School, West Roxbury, MA 02132, USA.
Kong
Lingxin
L
Wang
Xiaodan
X
Holmes
Courtney
C
Gao
Qingsheng
Q
Zhang
Guo-Rong
GR
Pfeilschifter
Josef
J
Goldstein
David S
DS
Geller
Alfred I
AI
D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000235:genetics* / Q000378:metabolism; D001522:Behavior, Animal; D002460:Cell Line; D004195:Disease Models, Animal; D004298:Dopamine / Q000096:biosynthesis; D005347:Fibroblasts / Q000378:metabolism; D006136:GTP Cyclohydrolase / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D018259:Herpesvirus 1, Human / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D017551:Microdialysis; D017072:Neostriatum / Q000378:metabolism; D010300:Parkinson Disease / Q000378:metabolism / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000378:metabolism; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; D014446:Tyrosine 3-Monooxygenase; D006136:GTP Cyclohydrolase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine