A Role for p38 Mitogen-activated Protein Kinase-mediated Threonine 30-dependent Norepinephrine Transporter Regulation in Cocaine Sensitization and Conditioned Place Preference

Padmanabhan Mannangatti,Kamalakkannan Narasimhanaidu,Mohamad Imad Damaj,Sammanda Ramamoorthy,Lankupalle Damodara Jayanthi

doi:10.1074/jbc.m114.612192

Padmanabhan Mannangatti, Kamalakkannan Narasimhanaidu + Show 3 more

Open Access

https://doi.org/10.1074/jbc.m114.612192

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Abstract

The noradrenergic and p38 mitogen-activated protein kinase (p38 MAPK) systems are implicated in cocaine-elicited behaviors. Previously, we demonstrated a role for p38 MAPK-mediated norepinephrine transporter (NET) Thr(30) phosphorylation in cocaine-induced NET up-regulation (Mannangatti, P., Arapulisamy, O., Shippenberg, T. S., Ramamoorthy, S., and Jayanthi, L. D. (2011) J. Biol. Chem. 286, 20239-20250). The present study explored the functional interaction between p38 MAPK-mediated NET regulation and cocaine-induced behaviors. In vitro cocaine treatment of mouse prefrontal cortex synaptosomes resulted in enhanced NET function, surface expression, and phosphorylation. Pretreatment with PD169316, a p38 MAPK inhibitor, completely blocked cocaine-mediated NET up-regulation and phosphorylation. In mice, in vivo administration of p38 MAPK inhibitor SB203580 completely blocked cocaine-induced NET up-regulation and p38 MAPK activation in the prefrontal cortex and nucleus accumbens. When tested for cocaine-induced locomotor sensitization and conditioned place preference (CPP), mice receiving SB203580 on cocaine challenge day or on postconditioning test day exhibited significantly reduced cocaine sensitization and CPP. A transactivator of transcription (TAT) peptide strategy was utilized to test the involvement of the NET-Thr(30) motif. In vitro treatment of synaptosomes with TAT-NET-Thr(30) (wild-type peptide) completely blocked cocaine-mediated NET up-regulation and phosphorylation. In vivo administration of TAT-NET-Thr(30) peptide but not TAT-NET-T30A (mutant peptide) completely blocked cocaine-mediated NET up-regulation and phosphorylation. In the cocaine CPP paradigm, mice receiving TAT-NET-Thr(30) but not TAT-NET-T30A on postconditioning test day exhibited significantly reduced cocaine CPP. Following extinction, TAT-NET-Thr(30) when given prior to cocaine challenge significantly reduced reinstatement of cocaine CPP. These results demonstrate that the direct inhibition of p38 MAPK or the manipulation of NET-Thr(30) motif/phosphorylation via a TAT peptide strategy prevents cocaine-induced NET up-regulation, locomotor sensitization, and CPP, suggesting a role for Thr(30)-linked NET regulation in cocaine-elicited behaviors.

Highlights

Cocaine-activated p38 MAPK-mediated norepinephrine transporter (NET) threonine 30 phosphorylation up-regulates NET
Similar to the observations made from our previous study [1], incubation of mouse prefrontal cortex (PFC) synaptosomes with 50 ␮M cocaine for 1 h produced a significant increase in NE transport capacity compared with vehicle controls (Fig. 1A)
Earlier studies indicated little evidence for NE playing a primary role in the reinforcing properties of psychomotor stimulants (44 – 46), more recent studies have documented that NET inhibition can play a significant role in cocaine-induced reinstatement [43]

Summary

Background

Cocaine-activated p38 MAPK-mediated norepinephrine transporter (NET) threonine 30 phosphorylation up-regulates NET. TATNET-Thr when given prior to cocaine challenge significantly reduced reinstatement of cocaine CPP These results demonstrate that the direct inhibition of p38 MAPK or the manipulation of NET-Thr motif/phosphorylation via a TAT peptide strategy prevents cocaine-induced NET up-regulation, locomotor sensitization, and CPP, suggesting a role for Thr30-linked NET regulation in cocaine-elicited behaviors. Initial in vitro experiments showed cocaine-mediated NET up-regulation and enhanced NET phosphorylation in mouse PFC synaptosomes These effects were completely blocked by prior treatment with either the p38 MAPK inhibitor PD169316 or TAT-NET-Thr. In vivo administration of the p38 MAPK inhibitor SB203580 or TAT-NET-Thr peptide significantly attenuated cocaine-induced locomotor sensitization and CPP These results suggested that p38 MAPK-mediated NET up-regulation is linked to cocaine-induced behaviors and that this regulation may have implications in the neuronal adaptations underlying cocaine addiction

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DISCUSSION