Synaptic Microtubule-Associated Protein EB3 and SRC Phosphorylation Mediate Structural and Behavioral Adaptations During Withdrawal From Cocaine Self-Administration

Abstract

Addictive behaviors, including relapse, are thought to depend in part on long-lasting drug-induced adaptations in dendritic spine signaling and morphology in the nucleus accumbens (NAc). While the influence of activity-dependent actin remodeling in these phenomena has been studied extensively, the role of microtubules and associated proteins remains poorly understood. We report that pharmacological inhibition of microtubule polymerization in the NAc inhibited locomotor sensitization to cocaine and contextual reward learning. We then investigated the roles of microtubule end-binding protein 3 (EB3) and SRC kinase in the neuronal and behavioral responses to volitionally administered cocaine. In synaptoneurosomal fractions from the NAc of self-administering male rats, the phosphorylation of SRC at an activating site was induced after 1 d of withdrawal, while EB3 levels were increased only after 30 d of withdrawal. Blocking SRC phosphorylation during early withdrawal by virally overexpressing SRCIN1, a negative regulator of SRC activity known to interact with EB3, abolished the incubation of cocaine craving in both male and female rats. Conversely, mimicking the EB3 increase observed after prolonged withdrawal increased the motivation to consume cocaine in male rats. In mice, the overexpression of either EB3 or SRCIN1 increased dendritic spine density and altered the spine morphology of NAc medium spiny neurons. Finally, a cocaine challenge after prolonged withdrawal recapitulated most of the synaptic protein expression profiles observed at early withdrawal. These findings suggest that microtubule-associated signaling proteins such as EB3 cooperate with actin remodeling pathways, notably SRC kinase activity, to establish and maintain long-lasting cellular and behavioral alterations following cocaine self-administration. Significance StatementDrug-induced morphological restructuring of dendritic spines of nucleus accumbens neurons is thought to be one of the cellular substrates of long-lasting drug-associated memories. The molecular basis of these persistent changes has remained incompletely understood. Here we implicate for the first time microtubule function in this process, together with key players such as microtubule-bound protein EB3 and synaptic SRC phosphorylation. We propose that microtubule and actin remodeling cooperate during withdrawal to maintain the plastic structural changes initially established by cocaine self-administration. This work opens new translational avenues for further characterization of microtubule-associated regulatory molecules as putative drug targets to tackle relapse to drug taking.

An optimized procedure for robust volitional drug intake in mice

“…The goal of preclinical SUD work is to understand drugtaking behavior on a mechanistic level that would allow for the development of novel pharmacotherapeutic targets for treatment in clinical populations [63][64][65]. In recent years, the field has focused on identifying the various molecular and circuity adaptations induced by drugs of abuse and underlying drug-associated behaviors [66][67][68][69][70][71][72][73][74][75]. However, our ability to effectively characterize the components driving drug-seeking and addictive phenotypes depend entirely on having translational and rigorous mouse models of volitional drug consumption.…”

The p140Cap adaptor protein as a molecular hub to block cancer aggressiveness

“…p140Cap is abundantly expressed in the cerebellum and the telencephalon, including the hippocampus, neocortex, entorhinal cortex, visual cortex [16] and in the nucleus accumbens [17,18]. p140Cap subcellular localization in neurons has been detected at the synaptic level, both in pre-and postsynaptic compartments [16,19]. In the post-synapse, p140Cap plays a key role in actin remodeling and in the regulation of dendritic spine morphology besides acting as a hub for the formation of postsynaptic complexes following the interaction with various proteins, underlying a potential role in these compartments [8,9,20,21].…”

“…In addition to Src and Csk, p140Cap also binds to Betacatenin through the 351-1051 amino-acid portion [10]. The terminal proline-rich domain of p140Cap associates with Vinexin [16], and Cortactin, a Src kinase substrate and an F-actin-binding protein [8,35]. A short 92 amino acid C-terminal region (aa 1124-1216) also directly interacts with EB3, a member of the microtubule plus-end tracking protein EB family in the brain [8].…”

“…A more detailed analysis of p140Cap expression and function in physiological conditions is available for the brain. p140Cap is abundantly expressed in the cerebellum and the telencephalon, including the hippocampus, neocortex, entorhinal cortex, visual cortex [ 16 ] and in the nucleus accumbens [ 17 , 18 ]. p140Cap subcellular localization in neurons has been detected at the synaptic level, both in pre- and postsynaptic compartments [ 16 , 19 ].…”

Cannabidiol effects on cocaine-seeking behaviour and incubation of craving in mice

“…Despite the vast research on cocaine-craving incubation in preclinical studies, most of the records to date have been extracted from rat models and only a handful of articles have been published addressing this issue in mouse models (Terrier et al, 2015;Nugent et al, 2017). Besides, long-access self-administration (6h/day) has been the preferred protocol to induce incubation of cocaine craving in both mice and rats (Conrad et al, 2008;Terrier et al, 2015;Calipari et al, 2019).…”