RT info:eu-repo/semantics/article
T1 Long-term controlled GDNF over-expression reduces dopamine transporter activity without affecting tyrosine hydroxylase expression in the rat mesostriatal system
A1 Castro Hernández, Javier Rafael
A1 Barroso Chinea, Pedro
A1 Cruz Muros, Ignacio
A1 Afonso Oramas, Domingo
A1 Salas Hernández, Josmar
A1 Chtarto, Abdelwahed
A1 Luis Ravelo, Diego
A1 Humbert-Claude, Marie
A1 Tenenbaum, Liliane
A1 González Hernández, Tomás
A2 Medicina Física y Farmacología
A2 Vulnerabilidad y plasticidad neuronal
K1 Dopamine transporter
K1 Tyrosine hydroxylase
K1 GDNF
K1 Inducible adeno-associated viral vectors
K1 Parkinson's disease
AB The dopamine (DA) transporter (DAT) is a plasma membrane glycoprotein expressed in dopaminergic (DA-)cells that takes back DA into presynaptic neurons after its release. DAT dysfunction has been involved in differentneuro-psychiatric disorders including Parkinson's disease (PD). On the other hand, numerous studies supportthat the glial cell line-derived neurotrophic factor (GDNF) has a protective effect on DA-cells. However, studiesin rodents show that prolonged GDNF over-expression may cause a tyrosine hydroxylase (TH, the limiting enzyme in DA synthesis) decline. The evidence of TH down-regulation suggests that another player in DA handling,DAT, may also be regulated by prolonged GDNF over-expression, and the possibility that this effect is induced atGDNF expression levels lower than those inducing TH down-regulation. This issue was investigated here usingintrastriatal injections of a tetracycline-inducible adeno-associated viral vector expressing human GDNF cDNA(AAV-tetON-GDNF) in rats, and doxycycline (DOX; 0.01, 0.03, 0.5 and 3 mg/ml) in the drinking water during5 weeks. We found that 3 mg/ml DOX promotes an increase in striatal GDNF expression of 12× basal GDNF levelsand both DA uptake decrease and TH down-regulation in its native and Ser40 phosphorylated forms. However,0.5 mg/ml DOX promotes a GDNF expression increase of 3× basal GDNF levels with DA uptake decrease butnot TH down-regulation. The use of western-blot under non-reducing conditions, co-immunoprecipitation andin situ proximity ligation assay revealed that the DA uptake decrease is associated with the formation of DAT dimers and an increase in DAT–α-synuclein interactions, without changes in total DAT levels or its compartmentaldistribution. In conclusion, at appropriate GDNF transduction levels, DA uptake is regulated through DAT protein–protein interactions without interfering with DA synthesis.
YR 2016
FD 2016
LK http://riull.ull.es/xmlui/handle/915/34777
UL http://riull.ull.es/xmlui/handle/915/34777
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 09-may-2024