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

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 STATEMENT Drug-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.

High yield of same-session EUS-guided liver biopsy by 19-gauge FNA needle in patients undergoing EUS to exclude biliary obstruction.

BACKGROUND: EUS-guided liver biopsy by Trucut yields variable specimen adequacy at high cost, limiting its utility. A modified EUS-guided technique with reliable adequacy could be a viable alternative to standard techniques in cost-effective clinical settings. OBJECTIVE: To describe our experience with EUS-guided liver biopsy by 19-gauge FNA, non-Trucut, needle in a cost-effective setting: patients with abnormal liver test results of unclear etiology referred for EUS to exclude biliary obstruction in whom an unrevealing EUS would have prompted a next-step liver biopsy by the referring physician. DESIGN: Prospective case series. SETTING: Tertiary-care teaching hospital. PATIENTS: Consecutive patients with abnormal liver tests referred for EUS. INTERVENTIONS: EUS-guided liver biopsy by 19-gauge FNA needle (non-Trucut). MAIN OUTCOME MEASUREMENTS: Diagnostic yield, specimen adequacy, and complications. An adequate specimen was defined as a length of 15 mm or longer and 6 or more complete portal tracts (CPTs). RESULTS: Between July 2008 and July 2011, 22 of 31 consecutive patients meeting inclusion criteria underwent unrevealing EUS with same-session EUS-guided liver biopsy by 19-gauge FNA needle. A median of 2 FNA passes (range 1-3) yielded a median specimen length of 36.9 mm (range 2-184.6 mm) with a median of 9 CPTs (range 1-73 CPTs). EUS-guided liver biopsies yielded a histologic diagnosis and adequate specimens in 20 of 22 patients (91%). Expanded experience led to improved specimen adequacy. There were no complications. LIMITATION: Small study size. CONCLUSIONS: EUS-guided liver biopsy by using a 19-gauge FNA needle appears to be feasible and safe and provides excellent diagnostic yield and specimen adequacy.

Prophylactic effect of flavanol rich preparation metabolites in promoting resilience to a mouse model of social stress.

Major depressive disorder (MDD) is a leading cause of disability, and there is an urgent need for new therapeutics. Stress-mediated induction of pro-inflammation in the periphery contributes to depression-like behaviors both in humans and in experimental models. Inflammatory cytokine interleukin-6 (IL-6) has emerged as a potential therapeutic target. Our studies demonstrated that metabolism of flavanol rich cocoa preparation (FRP) led to the accumulation of select phenolic acids that may contribute to its anti-inflammatory activity. Using a repeated social defeat stress (RSDS) model of depression, we showed that oral administration of FRP attenuates susceptibility to RSDS-mediated depression, supporting the further development of FRP as a novel therapeutic for the treatment of stress disorders and anxiety in humans.