Development of indole sulfonamides as cannabinoid receptor negative allosteric modulators

This Letter was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Scottish Universities Life Sciences Alliance (SULSA) in 2011Peer reviewedPostprin

Phosphorylation of ezrin on Thr567 is required for the synergistic activation of cell spreading by EPAC1 and protein kinase A in HEK293T cells

Recent studies have demonstrated that the actin binding protein, ezrin, and the cAMP-sensor, EPAC1, cooperate to induce cell spreading in response to elevations in intracellular cAMP. To investigate the mechanisms underlying these effects we generated a model of EPAC1-dependent cell spreading based on the stable transfection of EPAC1 into HEK293T (HEK293T–EPAC1) cells. We found that direct activation of EPAC1 with the EPAC-selective analogue, 8-pCPT-2′-O-Me-cAMP (007), promoted cell spreading in these cells. In addition, co-activation of EPAC1 and PKA, with a combination of the adenylate cyclase activator, forskolin, and the cAMP phosphodiesterase inhibitor, rolipram, was found to synergistically enhance cell spreading, in association with cortical actin bundling and mobilisation of ezrin to the plasma membrane. PKA activation was also associated with phosphorylation of ezrin on Thr567, as detected by an electrophoretic band mobility shift during SDS-PAGE. Inhibition of PKA activity blocked ezrin phosphorylation and reduced the cell spreading response to cAMP elevation to levels induced by EPAC1-activation alone. Transfection of HEK293T–EPAC1 cells with inhibitory ezrin mutants lacking the key PKA phosphorylation site, ezrin-Thr567Ala, or the ability to associate with actin, ezrin-Arg579Ala, promoted cell arborisation and blocked the ability of EPAC1 and PKA to further promote cell spreading. The PKA phospho-mimetic mutants of ezrin, ezrin-Thr567Asp had no effect on EPAC1-driven cell spreading. Our results indicate that association of ezrin with the actin cytoskeleton and phosphorylation on Thr567 are required, but not sufficient, for PKA and EPAC1 to synergistically promote cell spreading following elevations in intracellular cAMP

The F238L point mutation in the cannabinoid type 1 receptor enhances basal endocytosis via lipid rafts

Defining functional domains and amino acid residues in G protein coupled receptors (GPCRs) represents an important way to improve rational drug design for this major class of drug targets. The cannabinoid type 1 (CB1) receptor is one of the most abundant GPCRs in the central nervous system and is involved in many physiological and pathophysiological processes. Interestingly, mutagenesis of phenylalanine 238 to a leucine (CB1F238L) has been already linked to a number of both in vitro and in vivo alterations. While CB1F238L causes significantly reduced presynaptic neurotransmitter release at the cellular level, behaviorally this mutation induces increased risk taking, social play behavior and reward sensitivity in rats. However, the molecular mechanisms underlying these changes are not fully understood. In this study, we tested whether the F238L mutation affects trafficking and axonal/presynaptic polarization of the CB1 receptor in vitro. Steady state or ligand modulated surface expression and lipid raft association was analyzed in HEK293 cells stably expressing either CB1wt or CB1F238L receptor. Axonal/presynaptic polarization of the CB1F238L receptor was assessed in transfected primary hippocampal neurons. We show that in vitro the CB1F238L receptor displays increased association with lipid rafts, which coincides with increased lipid raft mediated constitutive endocytosis, leading to a reduction in steady state surface expression of the CB1F238L receptor. Furthermore, the CB1F238L receptor showed increased axonal polarization in primary hippocampal neurons. These data demonstrate that endocytosis of the CB1 receptor is an important mediator of axonal/presynaptic polarization and that phenylalanine 238 plays a key role in CB1 receptor trafficking and axonal polarization

A Cannabinoid CB 1 Receptor-Positive Allosteric Modulator Reduces Neuropathic Pain in the Mouse with No Psychoactive Effects

Peer reviewedPostprin

The F238L Point Mutation in the Cannabinoid Type 1 Receptor Enhances Basal Endocytosis via Lipid Rafts

Defining functional domains and amino acid residues in G protein coupled receptors (GPCRs) represent an important way to improve rational drug design for this major class of drug targets. The cannabinoid type 1 (CB1) receptor is one of the most abundant GPCRs in the central nervous system and is involved in many physiological and pathophysiological processes. Interestingly, cannabinoid type 1 receptor with a phenylalanine 238 to leucine mutation (CB1F238L) has been already linked to a number of both in vitro and in vivo alterations. While CB1F238L causes significantly reduced presynaptic neurotransmitter release at the cellular level, behaviorally this mutation induces increased risk taking, social play behavior and reward sensitivity in rats. However, the molecular mechanisms underlying these changes are not fully understood. In this study, we tested whether the F238L mutation affects trafficking and axonal/presynaptic polarization of the CB1 receptor in vitro. Steady state or ligand modulated surface expression and lipid raft association was analyzed in human embryonic kidney 293 (HEK293) cells stably expressing either wild-type cannabinoid type 1 receptor (CB1wt) or CB1F238L receptor. Axonal/presynaptic polarization of the CB1F238L receptor was assessed in transfected primary hippocampal neurons. We show that in vitro the CB1F238L receptor displays increased association with lipid rafts, which coincides with increased lipid raft mediated constitutive endocytosis, leading to a reduction in steady state surface expression of the CB1F238L receptor. Furthermore, the CB1F238L receptor showed increased axonal polarization in primary hippocampal neurons. These data demonstrate that endocytosis of the CB1 receptor is an important mediator of axonal/presynaptic polarization and that phenylalanine 238 plays a key role in CB1 receptor trafficking and axonal polarization

APOE ε2 resilience for Alzheimer’s disease is mediated by plasma lipid species: Analysis of three independent cohort studies

Introduction The apolipoprotein E (APOE) genotype is the strongest genetic risk factor for late-onset Alzheimer\u27s disease. However, its effect on lipid metabolic pathways, and their mediating effect on disease risk, is poorly understood. Methods We performed lipidomic analysis on three independent cohorts (the Australian Imaging, Biomarkers and Lifestyle [AIBL] flagship study, n = 1087; the Alzheimer\u27s Disease Neuroimaging Initiative [ADNI] 1 study, n = 819; and the Busselton Health Study [BHS], n = 4384), and we defined associations between APOE ε2 and ε4 and 569 plasma/serum lipid species. Mediation analysis defined the proportion of the treatment effect of the APOE genotype mediated by plasma/serum lipid species. Results A total of 237 and 104 lipid species were associated with APOE ε2 and ε4, respectively. Of these 68 (ε2) and 24 (ε4) were associated with prevalent Alzheimer\u27s disease. Individual lipid species or lipidomic models of APOE genotypes mediated up to 30% and 10% of APOE ε2 and ε4 treatment effect, respectively. Discussion Plasma lipid species mediate the treatment effect of APOE genotypes on Alzheimer\u27s disease and as such represent a potential therapeutic target

Small-molecule allosteric activators of PDE4 long form cyclic AMP phosphodiesterases

Cyclic AMP (cAMP) phosphodiesterase-4 (PDE4) enzymes degrade cAMP and underpin the compartmentalization of cAMP signaling through their targeting to particular protein complexes and intracellular locales. We describe the discovery and characterization of a small-molecule compound that allosterically activates PDE4 long isoforms. This PDE4-specific activator displays reversible, noncompetitive kinetics of activation (increased Vmax with unchanged Km), phenocopies the ability of protein kinase A (PKA) to activate PDE4 long isoforms endogenously, and requires a dimeric enzyme assembly, as adopted by long, but not by short (monomeric), PDE4 isoforms. Abnormally elevated levels of cAMP provide a critical driver of the underpinning molecular pathology of autosomal dominant polycystic kidney disease (ADPKD) by promoting cyst formation that, ultimately, culminates in renal failure. Using both animal and human cell models of ADPKD, including ADPKD patient-derived primary cell cultures, we demonstrate that treatment with the prototypical PDE4 activator compound lowers intracellular cAMP levels, restrains cAMP-mediated signaling events, and profoundly inhibits cyst formation. PDE4 activator compounds thus have potential as therapeutics for treating disease driven by elevated cAMP signaling as well as providing a tool for evaluating the action of long PDE4 isoforms in regulating cAMP-mediated cellular processes

Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

New Australian guidelines for the treatment of alcohol problems: an overview of recommendations

Summary of recommendations and levels of evidence Chapter 2: Screening and assessment for unhealthy alcohol use Screening Screening for unhealthy alcohol use and appropriate interventions should be implemented in general practice (Level A), hospitals (Level B), emergency departments and community health and welfare settings (Level C). Quantity–frequency measures can detect consumption that exceeds levels in the current Australian guidelines (Level B). The Alcohol Use Disorders Identification Test (AUDIT) is the most effective screening tool and is recommended for use in primary care and hospital settings. For screening in the general community, the AUDIT-C is a suitable alternative (Level A). Indirect biological markers should be used as an adjunct to screening (Level A), and direct measures of alcohol in breath and/or blood can be useful markers of recent use (Level B). Assessment Assessment should include evaluation of alcohol use and its effects, physical examination, clinical investigations and collateral history taking (Level C). Assessment for alcohol-related physical problems, mental health problems and social support should be undertaken routinely (GPP). Where there are concerns regarding the safety of the patient or others, specialist consultation is recommended (Level C). Assessment should lead to a clear, mutually acceptable treatment plan which specifies interventions to meet the patient’s needs (Level D). Sustained abstinence is the optimal outcome for most patients with alcohol dependence (Level C). Chapter 3: Caring for and managing patients with alcohol problems: interventions, treatments, relapse prevention, aftercare, and long term follow-up Brief interventions Brief motivational interviewing interventions are more effective than no treatment for people who consume alcohol at risky levels (Level A). Their effectiveness compared with standard care or alternative psychosocial interventions varies by treatment setting. They are most effective in primary care settings (Level A). Psychosocial interventions Cognitive behaviour therapy should be a first-line psychosocial intervention for alcohol dependence. Its clinical benefit is enhanced when it is combined with pharmacotherapy for alcohol dependence or an additional psychosocial intervention (eg, motivational interviewing) (Level A). Motivational interviewing is effective in the short term and in patients with less severe alcohol dependence (Level A). Residential rehabilitation may be of benefit to patients who have moderate-to-severe alcohol dependence and require a structured residential treatment setting (Level D). Alcohol withdrawal management Most cases of withdrawal can be managed in an ambulatory setting with appropriate support (Level B). Tapering diazepam regimens (Level A) with daily staged supply from a pharmacy or clinic are recommended (GPP). Pharmacotherapies for alcohol dependence Acamprosate is recommended to help maintain abstinence from alcohol (Level A). Naltrexone is recommended for prevention of relapse to heavy drinking (Level A). Disulfiram is only recommended in close supervision settings where patients are motivated for abstinence (Level A). Some evidence for off-label therapies baclofen and topiramate exists, but their side effect profiles are complex and neither should be a first-line medication (Level B). Peer support programs Peer-led support programs such as Alcoholics Anonymous and SMART Recovery are effective at maintaining abstinence or reductions in drinking (Level A). Relapse prevention, aftercare and long-term follow-up Return to problematic drinking is common and aftercare should focus on addressing factors that contribute to relapse (GPP). A harm-minimisation approach should be considered for patients who are unable to reduce their drinking (GPP). Chapter 4: Providing appropriate treatment and care to people with alcohol problems: a summary for key specific populations Gender-specific issues Screen women and men for domestic abuse (Level C). Consider child protection assessments for caregivers with alcohol use disorder (GPP). Explore contraceptive options with women of reproductive age who regularly consume alcohol (Level B). Pregnant and breastfeeding women Advise pregnant and breastfeeding women that there is no safe level of alcohol consumption (Level B). Pregnant women who are alcohol dependent should be admitted to hospital for treatment in an appropriate maternity unit that has an addiction specialist (GPP). Young people Perform a comprehensive HEEADSSS assessment for young people with alcohol problems (Level B). Treatment should focus on tangible benefits of reducing drinking through psychotherapy and engagement of family and peer networks (Level B). Aboriginal and Torres Strait Islander peoples Collaborate with Aboriginal or Torres Strait Islander health workers, organisations and communities, and seek guidance on patient engagement approaches (GPP). Use validated screening tools and consider integrated mainstream and Aboriginal or Torres Strait Islander-specific approaches to care (Level B). Culturally and linguistically diverse groups Use an appropriate method, such as the “teach-back” technique, to assess the need for language and health literacy support (Level C). Engage with culture-specific agencies as this can improve treatment access and success (Level C). Sexually diverse and gender diverse populations Be mindful that sexually diverse and gender diverse populations experience lower levels of satisfaction, connection and treatment completion (Level C). Seek to incorporate LGBTQ-specific treatment and agencies (Level C). Older people All new patients aged over 50 years should be screened for harmful alcohol use (Level D). Consider alcohol as a possible cause for older patients presenting with unexplained physical or psychological symptoms (Level D). Consider shorter acting benzodiazepines for withdrawal management (Level D). Cognitive impairment Cognitive impairment may impair engagement with treatment (Level A). Perform cognitive screening for patients who have alcohol problems and refer them for neuropsychological assessment if significant impairment is suspected (Level A). Summary of key recommendations and levels of evidence Chapter 5: Understanding and managing comorbidities for people with alcohol problems: polydrug use and dependence, co-occurring mental disorders, and physical comorbidities Polydrug use and dependence Active alcohol use disorder, including dependence, significantly increases the risk of overdose associated with the administration of opioid drugs. Specialist advice is recommended before treatment of people dependent on both alcohol and opioid drugs (GPP). Older patients requiring management of alcohol withdrawal should have their use of pharmaceutical medications reviewed, given the prevalence of polypharmacy in this age group (GPP). Smoking cessation can be undertaken in patients with alcohol dependence and/or polydrug use problems; some evidence suggests varenicline may help support reduction of both tobacco and alcohol consumption (Level C). Co-occurring mental disorders More intensive interventions are needed for people with comorbid conditions, as this population tends to have more severe problems and carries a worse prognosis than those with single pathology (GPP). The Kessler Psychological Distress Scale (K10 or K6) is recommended for screening for comorbid mental disorders in people presenting for alcohol use disorders (Level A). People with alcohol use disorder and comorbid mental disorders should be offered treatment for both disorders; care should be taken to coordinate intervention (Level C). Physical comorbidities Patients should be advised that alcohol use has no beneficial health effects. There is no clear risk-free threshold for alcohol intake. The safe dose for alcohol intake is dependent on many factors such as underlying liver disease, comorbidities, age and sex (Level A). In patients with alcohol use disorder, early recognition of the risk for liver cirrhosis is critical. Patients with cirrhosis should abstain from alcohol and should be offered referral to a hepatologist for liver disease management and to an addiction physician for management of alcohol use disorder (Level A). Alcohol abstinence reduces the risk of cancer and improves outcomes after a diagnosis of cancer (Level A)