Viral-mediated temporally controlled dopamine production in a rat model of Parkinson disease.
Regulation of gene expression is necessary to avoid possible adverse effects of gene therapy due to excess synthesis of transgene products. To reduce transgene expression, we developed a viral vector-mediated somatic regulation system using inducible Cre recombinase. A recombinant adeno-associated virus (AAV) vector expressing Cre recombinase fused to a mutated ligand-binding domain of the estrogen receptor alpha (CreER(T2)) was delivered along with AAV vectors expressing dopamine-synthesizing enzymes to rats of a Parkinson disease model. Treatment with 4-hydroxytamoxifen, a synthetic estrogen receptor modulator, activated Cre recombinase within the transduced neurons and induced selective excision of the tyrosine hydroxylase (TH) coding sequence flanked by loxP sites, leading to a reduction in transgene-mediated dopamine synthesis. Using this strategy, aromatic L-amino acid decarboxylase (AADC) activity was retained so that l-3,4-dihydroxyphenylalanine (L-dopa), a substrate for AADC, could be converted to dopamine in the striatum and the therapeutic effects of L-dopa preserved, even after reduction of TH expression in the case of dopamine overproduction. Our data demonstrate that viral vector-mediated inducible Cre recombinase can serve as an in vivo molecular switch, allowing spatial and temporal control of transgene expression, thereby potentially increasing the safety of gene therapy.
Li
Xiao-Gang
XG
Division of Neurology, Department of Medicine, Center for Molecular Medicine, Jichi Medical School, Tochigi 329-0498, Japan.
Okada
Takashi
T
Kodera
Mika
M
Nara
Yuko
Y
Takino
Naomi
N
Muramatsu
Chieko
C
Ikeguchi
Kunihiko
K
Urano
Fumi
F
Ichinose
Hiroshi
H
Metzger
Daniel
D
Chambon
Pierre
P
Nakano
Imaharu
I
Ozawa
Keiya
K
Muramatsu
Shin-Ichi
S
D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000378:metabolism; D002460:Cell Line; D003342:Corpus Striatum / Q000201:enzymology; D000229:Dependovirus / Q000235:genetics*; D004195:Disease Models, Animal; D004298:Dopamine / Q000096:biosynthesis*; D020847:Estrogen Receptor Modulators / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D019426:Integrases / Q000096:biosynthesis / Q000235:genetics; D007980:Levodopa / Q000378:metabolism; D008297:Male; D051379:Mice; D009474:Neurons / Q000201:enzymology; D010300:Parkinson Disease / Q000378:metabolism / Q000628:therapy*; D051381:Rats; D017208:Rats, Wistar; D011995:Recombination, Genetic; D013239:Stereotyped Behavior; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis / Q000235:genetics; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics
D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D014764:Viral Proteins; D013629:Tamoxifen; C016601:afimoxifene; D007980:Levodopa; D014446:Tyrosine 3-Monooxygenase; C045073:Cre recombinase; D019426:Integrases; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine