Tacrolimus-binding protein FKBP8 directs myosin light chain kinase-dependent barrier regulation and is a potential therapeutic target in Crohn's disease.

OBJECTIVE: Intestinal barrier loss is a Crohn's disease (CD) risk factor. This may be related to increased expression and enzymatic activation of myosin light chain kinase 1 (MLCK1), which increases intestinal paracellular permeability and correlates with CD severity. Moreover, preclinical studies have shown that MLCK1 recruitment to cell junctions is required for tumour necrosis factor (TNF)-induced barrier loss as well as experimental inflammatory bowel disease progression. We sought to define mechanisms of MLCK1 recruitment and to target this process pharmacologically. DESIGN: Protein interactions between FK506 binding protein 8 (FKBP8) and MLCK1 were assessed in vitro. Transgenic and knockout intestinal epithelial cell lines, human intestinal organoids, and mice were used as preclinical models. Discoveries were validated in biopsies from patients with CD and control subjects. RESULTS: MLCK1 interacted specifically with the tacrolimus-binding FKBP8 PPI domain. Knockout or dominant negative FKBP8 expression prevented TNF-induced MLCK1 recruitment and barrier loss in vitro. MLCK1-FKBP8 binding was blocked by tacrolimus, which reversed TNF-induced MLCK1-FKBP8 interactions, MLCK1 recruitment and barrier loss in vitro and in vivo. Biopsies of patient with CD demonstrated increased numbers of MLCK1-FKBP8 interactions at intercellular junctions relative to control subjects. CONCLUSION: Binding to FKBP8, which can be blocked by tacrolimus, is required for MLCK1 recruitment to intercellular junctions and downstream events leading to immune-mediated barrier loss. The observed increases in MLCK1 activity, MLCK1 localisation at cell junctions and perijunctional MLCK1-FKBP8 interactions in CD suggest that targeting this process may be therapeutic in human disease. These new insights into mechanisms of disease-associated barrier loss provide a critical foundation for therapeutic exploitation of FKBP8-MLCK1 interactions.

Positive Psychotherapy for Smoking Cessation: A Pilot Randomized Controlled Trial.

OBJECTIVE: Greater depressive symptoms and low positive affect (PA) are associated with poor smoking cessation outcomes. Smoking cessation approaches that incorporate a focus on PA may benefit smokers trying to quit. The purpose of this study was to conduct a pilot randomized clinical trial to compare standard smoking cessation treatment (ST) with smoking cessation treatment that targets positive affect, termed positive psychotherapy for smoking cessation (PPT-S). METHOD: Smokers who were seeking smoking cessation treatment were assigned by urn randomization to receive, along with 8 weeks of nicotine replacement therapy, either ST (n = 31) or PPT-S (n = 35). Seven-day point prevalence smoking abstinence was biochemically confirmed at 8, 16, and 26 weeks. RESULTS: Compared to ST, a greater percentage of participants in PPT-S were abstinent at 8 weeks, 16 weeks, and 26 weeks, but these differences were nonsignificant. In a more statistically powerful longitudinal model, participants in PPT-S had a significantly higher odds of abstinence (adjusted odds ratio [AOR] = 2.75; 95% CI = 1.02, 7.42; p = .046) across follow-ups compared to those in ST. The positive effect of PPT-S was stronger for those higher in PA (OR = 6.69, 95% CI = 1.16, 38.47, p = .03). Greater use of PPT-S strategies during the initial 8 weeks of quitting was associated with a less steep decline in smoking abstinence rates over time (OR = 2.64, 95% CI = 1.06, 6.56, p =.04). CONCLUSION: This trial suggests substantial promise for incorporating PPT into smoking cessation treatment.

Working Memory Moderates the Association Between Smoking Urge and Smoking Lapse Behavior After Alcohol Administration in a Laboratory Analogue Task.

INTRODUCTION: Lapses after smoking cessation often occur in the context of alcohol use, possibly because alcohol increases urge to smoke. Poor working memory, or alcohol-induced decrements in working memory, may influence this relationship by making it more difficult for an individual to resist smoking in the face of smoking urges. METHODS: Participants (n = 41) completed measures of working memory and urge to smoke before and after alcohol administration (placebo, 0.4 g/kg, and 0.8 g/kg, within subjects) and then participated in a laboratory analogue task in which smoking abstinence was monetarily incentivized. RESULTS: Working memory moderated the relationship between smoking urge and latency to smoke: for those with relatively poorer working memory, urge to smoke was more strongly and negatively associated with latency to smoke (i.e., higher urges were associated with shorter latency). CONCLUSIONS: Those with weak working memory may need additional forms of treatment to help them withstand smoking urges.

Acute effects of low and high dose alcohol on smoking lapse behavior in a laboratory analogue task.

RATIONALE: Smoking lapses (i.e., returns to smoking after quitting) often occur following alcohol consumption with observational data suggesting greater quantities of alcohol lead to greater risk. However, a causal dose-dependent effect of alcohol consumption on smoking lapse behavior has not been established, and the mechanisms that might account for such an effect have not been tested. OBJECTIVES: In a within-subjects design, we examined the effects of low- (0.4 g/kg) and high-dose (0.8 g/kg) alcohol, relative to placebo, on smokers' ability to resist initiating smoking after acute smoking abstinence. METHODS: Participants were 100 heavy alcohol drinkers, smoking 10-30 cigarettes per day. Across three separate days, participants consumed placebo, low-dose, or high-dose alcohol following 3 h of smoking abstinence and, 35 min later, were offered the opportunity to smoke while resisting smoking was monetarily reinforced proportional to the amount of time delayed. RESULTS: Consistent with a dose-response effect, participants smoked 3.35 min (95 % confidence intervals (CI) [-7.09, 0.40], p = .08) earlier following low-dose alcohol and 6.36 min (95 % CI [-9.99, -2.73], p = .0006) earlier following high-dose alcohol compared to drinking a placebo beverage. Effects of dose on smoking behavior were partially mediated by increases in urge to smoke. There was no evidence that alcohol's effects on urge to smoke or ability to resist smoking were mediated through its stimulating or sedating effects. CONCLUSIONS: Alcohol can reduce the ability to resist smoking in a dose-dependent fashion, in part, due to its effect on increasing the intensity of smoking urges.

Positive Psychotherapy for Smoking Cessation: Treatment Development, Feasibility and Preliminary Results.

Low positive and high negative affect predict low rates of smoking abstinence among smokers making a quit attempt. Positive Psychotherapy can both increase positive affect and decrease negative affect and therefore may be a useful adjunct to behavioral smoking counseling. The purpose of the present study was to assess the feasibility and acceptability of a Positive Psychotherapy for Smoking Cessation (PPT-S) intervention that integrates standard smoking cessation counseling with nicotine patch and a package of positive psychology interventions. We delivered PPT-S to 19 smokers who were low in positive affect at baseline. Rates of session attendance and satisfaction with treatment were high, and most participants reported using and benefiting from the positive psychology interventions. Almost one-third of participants (31.6%) sustained smoking abstinence for 6 months after their quit date. Future studies to assess the relative efficacy of PPT-S compared to standard smoking cessation treatment are warranted.

Length of smoking deprivation moderates the effects of alcohol administration on urge to smoke.

Although smoking deprivation is often used in laboratory studies to induce urges to smoke cigarettes, the optimal length of deprivation has not been established. Previous research showed that overnight abstinence from cigarettes led to high baseline urge to smoke that potentially masked alcohol's acute effects on urge to smoke (Kahler et al., 2012). The current study examined whether alcohol's effects on smoking urge were more pronounced when a shorter length of smoking deprivation was used (i.e., 3h instead of overnight abstinence). Using a balanced placebo design for alcohol administration, we found that participants experienced a significant increase in self-reported urge to smoke when administered alcohol after a 3-h smoking deprivation (n=32), whereas this effect was smaller and nonsignificant when smokers were required to be abstinent overnight (n=96). Research on factors that heighten smoking urges may find stronger effects if a 3-h deprivation is used compared to using overnight abstinence.

Motivational interviewing versus brief advice for cigarette smokers in residential alcohol treatment.

Residential treatment for substance use disorders (SUD) provides opportunity for smoking intervention. A randomized controlled trial compared: (1) motivational interviewing (MI) to brief advice (BA), (2) in one session or with two booster sessions, for 165 alcoholics in SUD treatment. All received nicotine replacement (NRT). MI and BA produced equivalent confirmed abstinence, averaging 10% at 1 month, and 2% at 3, 6 and 12 months. However, patients with more drug use pretreatment (>22 days in 6 months) given BA had more abstinence at 12 months (7%) than patients in MI or with less drug use (all 0%). Boosters produced 16-31% fewer cigarettes per day after BA than MI. Substance use was unaffected by treatment condition or smoking cessation. Motivation to quit was higher after BA than MI. Thus, BA plus NRT may be a cost-effective way to reduce smoking for alcoholics with comorbid substance use who are not seeking smoking cessation.

Marijuana and self-regulation: examining likelihood and intensity of use and problems.

It is important to understand the individual differences that contribute to greater frequency or intensity of marijuana use, or greater frequency of experiencing marijuana-related problems. The current study examined several elements of behavioral and emotional self-regulation as predictors of the likelihood and intensity of both marijuana use and marijuana-related problems. As predicted, indices of behavioral self-regulation (self-control, sensation seeking) were better predictors of marijuana use, while indices of emotional self-regulation (affect, distress tolerance, and emotional instability) better predicted marijuana-related problems. Surprisingly, urgency was not related to use but was predictive of problems, and there were no significant interactions between behavioral and emotional self-regulation in predicting either use or problems. From these findings we conclude that while behavioral dysregulation may put individuals at risk for using marijuana, or using it more frequently, it is those individuals with difficulty in emotional self-regulation that are at risk for experiencing negative consequences as a result of their marijuana use. Clinically, these data are relevant; clinicians might focus more on addressing emotional regulation in order to lessen or eliminate the consequences of marijuana use.

Working memory and impulsivity predict marijuana-related problems among frequent users.

BACKGROUND: Although marijuana is the most commonly used illicit substance in the US, only a small portion of users go on to develop dependence, suggesting that there are substantial individual differences in vulnerability to marijuana-related problems among users. Deficits in working memory and high trait impulsivity are two factors that may place marijuana users at increased risk for experiencing related problems. METHODS: Using baseline data from an experimental study that recruited 104 frequent marijuana users (M=71.86% of prior 60 days, SD=22%), we examined the associations of working memory and trait impulsivity with marijuana-related problems. RESULTS: Lower working memory, as measured by Trail Making Test B, but not short-term memory capacity, predicted more marijuana-related problems. Higher trait impulsivity scores were independently associated with greater number of problems. CONCLUSIONS: Results suggest that marijuana users with reduced executive cognitive ability are more susceptible to developing problems related to their use. Trait impulsivity and executive working memory appear to be independent risk factors for experiencing marijuana-related problems.

[(3)H]Adenosine uptake in brainstem membranes of CD-1 mice lacking the adenosine A(2a) receptor.

Previous studies in our laboratory have demonstrated a decrease in [(3)H]nitrobenzylthioinosine binding sites in the brainstem of adenosine A(2a) receptor knockout mice, particularly in the brain nuclei involved in central control of cardiovascular function [Brain Research 877 (2000) 160]. The present study aimed to correlate this decrease, shown using autoradiography, with a functional change using a previously described method of [(3)H]adenosine uptake in a membrane preparation from the brainstem of wildtype CD - 1 and homozygous mutant mice lacking the adenosine A(2a) receptor. A statistically significant decrease was shown in the mean V(MAX) value obtained from homozygous mutant preparations (4.7 +/- 1.3 fmol/mg protein/20 s, P < 0.05, n = 4) compared to that obtained from wildtype controls (51.6 +/- 4.2 fmol/mg protein/20 s, n = 4). Competition studies using nucleoside uptake inhibitors showed a statistically significant increase in the log IC(50) values for dipyridamole (Wildtype: -4.3 +/- 0.2, Homozygous mutant: -8.3 +/- 0.4, n=5, P < 0.05) and dilazep (Wildtype: -3.9 +/- 0.8, Homozygous mutant: -8.3 +/- 0.8, n=5, P < 0.05) in the preparations using homozygous mutant tissue. The present study, in conjunction with the results of previous studies [Brain Research 877 (2000) 160], indicates that components of purinergic neurotransmission system have apparently adjusted in compensation for the lack of the A(2a) receptor.