Cyclin-dependent kinase 5 inhibition impairs dopamine transporter internalization: implications for Attention-Deficit Hyperactivity Disorder

FERNÁNDEZ GUILLERMO; QUASSOLLO GONZALO; KRAPACHER FAVIO; FERRERAS SOLEDAD; PISANO MARÍA VICTORIA; PAGLINI GABRIELA

Rio de Janeiro

Congreso; 9th IBRO World Congress on Neuroscience; 2015

IBRO


Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood brain disorders. Previous studies from our lab have demonstrated that transgenic mice lacking p35 protein (p35KO), the specific activator of Cyclin dependent kinase 5 (Cdk5) exhibit behaviors resemble those described in animal models of ADHD. P35KO mice show spontaneous locomotor hyperactivity, less anxiety-like behaviours, elevated striatal Dopamine (DA) synthesis, but with a low DA turnover. These behavioral and biochemical phenotypes are reverted by Methylphenidate and d-Amphetamine (Amph), drugs used in ADHD treatment. Although we have shown that p35KO mice have an altered dopaminergic system, the trafficking and activity of Dopamine Transporter (DAT) still remain unknown. In this work we studied the role of Cdk5 activity in DAT constitutive and substrate-mediated trafficking in N2A neuroblastoma cells using inmunofluorescence microscopy. We found that Amph exposure increased DAT localization in endosomes compartments. In order to evaluate Cdk5 regulation of DAT internalization, we inhibited Cdk5 activity by two methods, 1-small interference RNA (SiCdk5) and 2- the Cdk5 inhibitor Roscovitine. We found that inhibition of Cdk5 activity impaired DAT constitutive and substrate induced DAT internalization. These results suggest that Cdk5 activity modulates DAT trafficking to the plasma membrane, and its superficial levels. These findings may help us to elucidate DAT function in the hyperdopaminergic system of p35KO mouse, animal model of ADHD.