PAM-altering SNP-based allele-specific CRISPR-Cas9 therapeutic strategies for Huntington's disease.

Huntington's disease (HD) is caused by an expanded CAG repeat in huntingtin (HTT). Since HD is dominant and loss of HTT leads to neurological abnormalities, safe therapeutic strategies require selective inactivation of mutant HTT. Previously, we proposed a concept of CRISPR-Cas9 using mutant-specific PAM sites generated by SNPs to selectively inactivate mutant HTT. Aiming at revealing suitable targets for clinical development, we analyzed the largest HD genotype dataset to identify target PAM-altering SNPs (PAS) and subsequently evaluated their allele specificities. The gRNAs based on the PAM sites generated by rs2857935, rs16843804, and rs16843836 showed high levels of allele specificity in patient-derived cells. Simultaneous use of two gRNAs based on rs2857935-rs16843804 or rs2857935-rs16843836 produced selective genomic deletions in mutant HTT and prevented the transcription of mutant HTT mRNA without impacting the expression of normal counterpart or re-integration of the excised fragment elsewhere in the genome. RNA-seq and off-target analysis confirmed high levels of allele specificity and the lack of recurrent off-targeting. Approximately 60% of HD subjects are eligible for mutant-specific CRISPR-Cas9 strategies of targeting one of these three PAS in conjunction with one non-allele-specific site, supporting high applicability of PAS-based allele-specific CRISPR approaches in the HD patient population.

Allele-specific silencing of the gain-of-function mutation in Huntington's disease using CRISPR/Cas9.

Dominant gain-of-function mechanisms in Huntington's disease (HD) suggest that selective silencing of mutant HTT produces robust therapeutic benefits. Here, capitalizing on exonic protospacer adjacent motif-altering (PAM-altering) SNP (PAS), we developed an allele-specific CRISPR/Cas9 strategy to permanently inactivate mutant HTT through nonsense-mediated decay (NMD). Comprehensive sequence/haplotype analysis identified SNP-generated NGG PAM sites on exons of common HTT haplotypes in HD subjects, revealing a clinically relevant PAS-based mutant-specific CRISPR/Cas9 strategy. Alternative allele of rs363099 (29th exon) eliminates the NGG PAM site on the most frequent normal HTT haplotype in HD, permitting mutant-specific CRISPR/Cas9 therapeutics in a predicted ~20% of HD subjects with European ancestry. Our rs363099-based CRISPR/Cas9 showed perfect allele specificity and good targeting efficiencies in patient-derived cells. Dramatically reduced mutant HTT mRNA and complete loss of mutant protein suggest that our allele-specific CRISPR/Cas9 strategy inactivates mutant HTT through NMD. In addition, GUIDE-Seq analysis and subsequent validation experiments support high levels of on-target gene specificity. Our data demonstrate a significant target population, complete mutant specificity, decent targeting efficiency in patient-derived cells, and minimal off-target effects on protein-coding genes, proving the concept of PAS-based allele-specific NMD-CRISPR/Cas9 and supporting its therapeutic potential in HD.

Mental disorder symptoms during the COVID-19 pandemic in Latin America - a systematic review and meta-analysis.

AIMS: There is a lack of evidence related to the prevalence of mental health symptoms as well as their heterogeneities during the coronavirus disease 2019 (COVID-19) pandemic in Latin America, a large area spanning the equator. The current study aims to provide meta-analytical evidence on mental health symptoms during COVID-19 among frontline healthcare workers, general healthcare workers, the general population and university students in Latin America. METHODS: Bibliographical databases, such as PubMed, Embase, Web of Science, PsycINFO and medRxiv, were systematically searched to identify pertinent studies up to August 13, 2021. Two coders performed the screening using predefined eligibility criteria. Studies were assigned quality scores using the Mixed Methods Appraisal Tool. The double data extraction method was used to minimise data entry errors. RESULTS: A total of 62 studies with 196 950 participants in Latin America were identified. The pooled prevalence of anxiety, depression, distress and insomnia was 35%, 35%, 32% and 35%, respectively. There was a higher prevalence of mental health symptoms in South America compared to Central America (36% v. 28%, p < 0.001), in countries speaking Portuguese (40%) v. Spanish (30%). The pooled prevalence of mental health symptoms in the general population, general healthcare workers, frontline healthcare workers and students in Latin America was 37%, 34%, 33% and 45%, respectively. CONCLUSIONS: The high yet heterogenous level of prevalence of mental health symptoms emphasises the need for appropriate identification of psychological interventions in Latin America.

Meta-analytic evidence of depression and anxiety in Eastern Europe during the COVID-19 pandemic.

Objective: To perform a systematic and meta-analysis on the prevalence rates of mental health symptoms including anxiety and depression during the COVID-19 pandemic in the general population in Eastern Europe, as well as three select sub-populations: students, general healthcare workers, and frontline healthcare workers. Data sources: Studies in PubMed, Embase, Web of Science, PsycINFO, and medRxiv up to 6 February 2021. Eligibility criteria and data analysis: Prevalence rates of mental health symptoms in the general population and key sub-populations during the COVID-19 pandemic in Eastern Europe. Data were pooled using a random-effects meta-analysis to estimate the prevalence rates of anxiety and depression. Results: The meta-analysis identifies and includes 21 studies and 26 independent samples in Eastern Europe. Poland (n = 4), Serbia (n = 4), Russia (n = 3), and Croatia (n = 3) had the greatest number of studies. To our knowledge, no studies have been conducted in eleven Eastern European countries including Hungary, Slovakia, and Slovenia. The pooled prevalence of anxiety in 18 studies with 22 samples was 30% (95% CI: 24-37%) pooled prevalence of depression in 18 studies with 23 samples was 27% (95% CI: 21-34%). Implications: The cumulative evidence from the meta-analysis reveals high prevalence rates of clinically significant symptoms during the COVID-19 pandemic in Eastern Europe. The findings suggest evidence of a potential mental health crisis in Eastern Europe during the ongoing COVID-19 pandemic. Our synthesis also reveals a relative lack of studies in certain Eastern European countries as well as high heterogeneities among the existing studies, calling for more effort to achieve evidence-based mental healthcare in Eastern Europe.

Objetivo: Realizar un metanálisis sistemático sobre las tasas de prevalencia de síntomas de salud mental, incluidos ansiedad y depresión durante la pandemia de COVID-19 en la población general de Europa del Este, así como en tres subpoblaciones seleccionadas: estudiantes, trabajadores sanitarios generales y trabajadores sanitarios de primera línea.Fuentes de datos: Estudios en PubMed, Embase, Web of Science, PsycINFO y medRxiv hasta el 6 de febrero de 2021.Criterios de elegibilidad y análisis de datos: Tasas de prevalencia de síntomas de salud mental en la población general y subpoblaciones claves durante la pandemia de COVID-19 en Europa del Este. Los datos se combinaron mediante un metanálisis de efectos aleatorios para estimar las tasas de prevalencia de ansiedad y depresión.Resultados: El metanálisis identifica e incluye 21 estudios y 26 muestras independientes en Europa del Este. Polonia (n = 4), Serbia (n = 4), Rusia (n = 3) y Croacia (n = 3) tuvieron el mayor número de estudios. Hasta donde sabemos, no se han realizado estudios en once países de Europa del Este, incluidos Hungría, Eslovaquia y Eslovenia. La prevalencia combinada de ansiedad en 18 estudios con 22 muestras fue de 30% (IC del 95%: 24­37%) y la prevalencia combinada de depresión en 18 estudios con 23 muestras fue de 27% (IC del 95%: 21­34%).Implicaciones: La evidencia acumulada del metanálisis revela altas tasas de prevalencia de síntomas clínicamente significativos durante la pandemia de COVID-19 en Europa del Este. Los hallazgos sugieren evidencia de una posible crisis de salud mental en Europa del Este durante la pandemia de COVID-19 en curso. Nuestra síntesis también revela una relativa falta de estudios en ciertos países de Europa del Este, así como una gran heterogeneidad entre los estudios existentes, lo que exige un mayor esfuerzo para lograr una atención de la salud mental basada en la evidencia en Europa del Este.

A Systematic Review and Meta-Analysis of Symptoms of Anxiety, Depression, and Insomnia in Spain in the COVID-19 Crisis.

BACKGROUND: General population, frontline healthcare workers (HCWs), and adult students in Spain are at risk of anxiety, depression, and insomnia symptoms during the COVID-19 crisis. A meta-analysis of the individual studies on these symptoms would provide systematic evidence to aid policymakers and researchers in focusing on prevalence, risk, and best interventions. OBJECTIVE: This paper aims to be the first meta-analysis and systematic review to calculate the prevalence of anxiety, depression, and insomnia symptoms in Spain's adult population (general population, frontline healthcare workers (HCWs), and adult students) during the Covid-19 epidemic. METHOD: Random-effect meta-analysis was used to estimate the prevalence of anxiety, depression, and insomnia. RESULTS: The meta-analysis includes 28 studies with 38 individual samples in Spain. The pooled prevalence of anxiety symptoms in 22 studies comprising a sample population of 82,024 was 20% (95% CI: 15-25%), that of depression symptoms in 22 articles with a total sample comprising 82,890 individuals was 22% (95% CI: 18-28%), and that of insomnia symptoms in three articles with a sample population of 745 was 57% (95% CI: 48-66%. CONCLUSIONS: The accumulative evidence reveals that adults in Spain suffered higher prevalence rates of mental symptoms during the COVID-19 crisis, with a significantly higher rate relative to other countries such as China. Our synthesis also reveals a relative lack of studies on frontline and general HCWs in Spain.

A systematic review and meta-analysis of the mental health symptoms during the Covid-19 pandemic in Southeast Asia.

AIMS: The Covid-19 pandemic has had a substantial impact on the mental health of the general public and high-risk groups worldwide. Due to its proximity and close links to China, Southeast Asia was one of the first regions to be affected by the outbreak. The aim of this systematic review was to evaluate the prevalence of anxiety, depression and insomnia in the general adult population and healthcare workers (HCWs) in Southeast Asia during the course of the first year of the pandemic. METHODS: Several literature databases were systemically searched for articles published up to February 2021 and two reviewers independently evaluated all relevant studies using pre-determined criteria. The prevalence rates of mental health symptoms were calculated using a random-effect meta-analysis model. RESULTS: In total, 32 samples from 25 studies with 20 352 participants were included. Anxiety was assessed in all 25 studies and depression in 15 studies with pooled prevalence rates of 22% and 16%, respectively. Only two studies assessed insomnia, which was estimated at 19%. The prevalence of anxiety and depression was similar among frontline HCWs (18%), general HCWs (17%), and students (20%) while being noticeably higher in the general population (27%). CONCLUSIONS: This is the first systematic review to investigate the mental health impact of the Covid-19 pandemic in Southeast Asia. A considerable proportion of the general population and HCWs reported mild to moderate symptoms of anxiety and depression; the pooled prevalence rater, however, remain significantly lower than those reported in other areas such as China and Europe.

Mental Health during the COVID-19 Crisis in Africa: A Systematic Review and Meta-Analysis.

We aim to provide a systematic review and meta-analysis of the prevalence rates of mental health symptoms among major African populations during the COVID-19 pandemic. We include articles from PubMed, Embase, Web of Science, PsycINFO, and medRxiv between 1 February 2020 and 6 February 2021, and pooled data using random-effects meta-analyses. We identify 28 studies and 32 independent samples from 12 African countries with a total of 15,071 participants. The pooled prevalence of anxiety was 37% in 27 studies, of depression was 45% in 24 studies, and of insomnia was 28% in 9 studies. The pooled prevalence rates of anxiety, depression, and insomnia in North Africa (44%, 55%, and 31%, respectively) are higher than those in Sub-Saharan Africa (31%, 30%, and 24%, respectively). We find (a) a scarcity of studies in several African countries with a high number of COVID-19 cases; (b) high heterogeneity among the studies; (c) the extent and pattern of prevalence of mental health symptoms in Africa is high and differs from elsewhere-more African adults suffer from depression rather than anxiety and insomnia during COVID 19 compared to adult populations in other countries/regions. Hence, our findings carry crucial implications and impact future research to enable evidence-based medicine in Africa.

DNA methylation study of Huntington's disease and motor progression in patients and in animal models.

Although Huntington's disease (HD) is a well studied Mendelian genetic disorder, less is known about its associated epigenetic changes. Here, we characterize DNA methylation levels in six different tissues from 3 species: a mouse huntingtin (Htt) gene knock-in model, a transgenic HTT sheep model, and humans. Our epigenome-wide association study (EWAS) of human blood reveals that HD mutation status is significantly (p < 10-7) associated with 33 CpG sites, including the HTT gene (p = 6.5 × 10-26). These Htt/HTT associations were replicated in the Q175 Htt knock-in mouse model (p = 6.0 × 10-8) and in the transgenic sheep model (p = 2.4 × 10-88). We define a measure of HD motor score progression among manifest HD cases based on multiple clinical assessments. EWAS of motor progression in manifest HD cases exhibits significant (p < 10-7) associations with methylation levels at three loci: near PEX14 (p = 9.3 × 10-9), GRIK4 (p = 3.0 × 10-8), and COX4I2 (p = 6.5 × 10-8). We conclude that HD is accompanied by profound changes of DNA methylation levels in three mammalian species.

Discovery of N-[(4R)-6-(4-chlorophenyl)-7-(2,4-dichlorophenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl]-5-methyl-1H-pyrazole-3-carboxamide (MK-5596) as a novel cannabinoid-1 receptor (CB1R) inverse agonist for the treatment of obesity.

This paper describes the discovery of N-[(4R)-6-(4-chlorophenyl)-7-(2,4-dichlorophenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl]-5-methyl-1H-pyrazole-3-carboxamide (MK-5596, 12c) as a novel cannabinoid-1 receptor (CB1R) inverse agonist for the treatment of obesity. Structure-activity relationship (SAR) studies of lead compound 3, which had off-target hERG (human ether-a-go-go related gene) inhibition activity, led to the identification of several compounds that not only had attenuated hERG inhibition activity but also were subject to glucuronidation in vitro providing the potential for multiple metabolic clearance pathways. Among them, pyrazole 12c was found to be a highly selective CB1R inverse agonist that reduced body weight and food intake in a DIO (diet-induced obese) rat model through a CB1R-mediated mechanism. Although 12c was a substrate of P-glycoprotein (P-gp) transporter, its high in vivo efficacy in rodents, good pharmacokinetic properties in preclinical species, good safety margins, and its potential for a balanced metabolism profile in man allowed for the further evaluation of this compound in the clinic.

1-Sulfonyl-4-acylpiperazines as selective cannabinoid-1 receptor (CB1R) inverse agonists for the treatment of obesity.

A novel series of 1-sulfonyl-4-acylpiperazines as selective cannabinoid-1 receptor (CB1R) inverse agonists was discovered through high throughput screening (HTS) and medicinal chemistry lead optimization. Potency and in vivo properties were systematically optimized to afford orally bioavailable, highly efficacious, and selective CB1R inverse agonists that caused food intake suppression and body weight reduction in diet-induced obese rats and dogs. It was found that the receptor binding assay predicted in vivo efficacy better than functional antagonist/inverse agonist activities. This observation expedited the structure-activity relationship (SAR) analysis and may have implications beyond the series of compounds presented herein.

Reduced sensitivity to diet-induced obesity in mice carrying a mutant 5-HT6 receptor.

We investigated the feeding behavior of mice carrying a non-functional 5-hydroxytryptamine-6 receptor (5-HT6). Homozygous mutant mice on C57BL/6 background were grossly normal and showed normal growth when fed a low-fat chow diet. When fed a high-fat diet, the mutant mice consumed approximately 8% less food while gaining approximately 35% less weight over an 11-week study period than did the wild-type controls. Body composition analysis of mice on high-fat feeding showed that the reduced weight gain in the mutant mice was mostly due to reduced fat accumulation. Given the documented role of the serotonin systems in human feeding, our results provide an interesting piece of evidence supporting the development of 5-HT6 receptor antagonists for treating obesity.

Pharmacological evaluation of LH-21, a newly discovered molecule that binds to cannabinoid CB1 receptor.

LH-21 (5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-hexyl-1H-1,2,4-triazole) was previously reported as a neutral antagonist at the cannabinoid CB1 receptor which, despite its reported poor ability to penetrate into the brain, suppressed food intake and body weight in rats by intraperitoneal administration. In the present study, we studied the mechanism of action of LH-21 by characterizing its in vitro pharmacological properties and in vivo efficacy. LH-21 inhibited the binding of [3H]CP55940 to cloned human and rat CB1 receptors with IC50 values of 631+/-98 nM, and 690+/-41 nM, respectively, and acted as an inverse agonist in a cAMP functional assay using cultured cells expressing human, rat or mouse CB1 receptor. The compound was shown to be brain-penetrant in rats by intravenous administration. Importantly, a single dose of LH-21 (60 mg/kg, i.p.) caused a similar suppression of overnight food intake and body weight gain in wild-type and CB1 receptor knockout mice. Our results suggest that LH-21 is a low affinity inverse agonist for the CB1 receptor and does not act on the CB1 receptor to inhibit food intake in mice.

The triple uptake inhibitor (1R,5S)-(+)-1-(3,4-dichlorophenyl)-3-azabicyclo[3.1.0] hexane hydrochloride (DOV 21947) reduces body weight and plasma triglycerides in rodent models of diet-induced obesity.

Selective inhibitors of biogenic amine (e.g., serotonin, norepinephrine, and dopamine) uptake exhibit varying degrees of safety and efficacy as antiobesity agents. Moreover, preclinical findings suggest that the combined inhibition of monoamine neurotransmitter transporters synergistically enhances antiobesity activity. (1R,5S)-(+)-1-(3,4-Dichlorophenyl)-3-azabicyclo-[3.1.0] hexane hydrochloride (DOV 21947) inhibits norepinephrine, 5-hydroxytryptamine, and dopamine uptake, and it reduces body weight in rodent models of diet-induced obesity (DIO). DIO rats treated orally with DOV 21947 for 1 to 24 days showed significantly lower body weights than vehicle-treated DIO rats. The decrease in body weight resulted specifically from a loss of retroperitoneal and mesenteric depots of white adipose tissue. DOV 21947 also reduced daily food intake in DIO rats, but consumption returned to control levels after 11 days of treatment. With the exception of a decrease in triglyceride levels, blood chemistry was unaltered after 24 days of DOV 21947 treatments. DOV 21947 had no effect on motor activity. Although DOV 21947 increased respiratory rate and decreased the tidal volume of normal rats, it did not alter the minute volume. In addition, DOV 21947 did not significantly affect blood pressure, heart rate, electrocardiographic indices or body temperature in telemeterized dogs. However, it caused a sustained, but reversible reduction in the rate of body weight gain for as long as 6 months in normal rats, and for up to 1 year in normal dogs. In summary, DOV 21947 is effective in causing a sustained and selective reduction in fat content and triglyceride levels in animal models of obesity without significantly altering vital organ function.

The mu-opioid receptor subtype is required for the anorectic effect of an opioid receptor antagonist.

A diaryl ether derivative, (6-(4-{[(3-methylbutyl)amino]methyl}phenoxy)nicotinamide, was prepared and investigated for its biochemical properties at cloned opioid receptors and its pharmacological effects on animal feeding. The compound displaced [(3)H]DAMGO binding of human mu-opioid receptor, [(3)H]U-69593 of human kappa-opioid receptor, and [(3)H]DPDPE of human delta-opioid receptor with IC(50) values of 0.5+/-0.2 nM, 1.4+/-0.2 nM, and 71+/-15 nM, respectively. The compound also potently inhibited [(3)H]DAMGO binding of cloned mouse and rat mu-opioid receptors (IC(50) approximately 1 nM), and acted as a competitive antagonist in a cAMP functional assay using cultured cells expressing human or mouse mu-opioid receptors. Following a single oral administration in diet-induced obese mice (at 10 or 50 mg/kg) or rats (at 1, 3, or 10 mg/kg), the compound caused a dose-dependent suppression of acute food intake and body weight gain in both species. Importantly, the anorectic efficacy of the compound was mostly diminished in mice deficient in the mu-opioid receptor. Our results suggest an important role for the mu-opioid receptor subtype in animal feeding regulation and support the development of mu-selective antagonists as potential agents for treating human obesity.

Effects of the CB1 cannabinoid receptor inverse agonist AM251 on food intake and body weight in mice lacking mu-opioid receptors.

We used mu-opioid receptor-deficient (MOR-/-) mice to determine the effects of the CB1 cannabinoid receptor inverse agonist AM251 on feeding in the absence of MOR signaling. A single dose of AM251 at 0.6, 2 or 6 mg/kg caused similar dose-dependent suppression of food intake in wild-type and MOR-/- mice. Administration of AM251 at 3 mg/kg/day for 9 consecutive days also led to a similar reduction ( approximately 8%) in body weight in wild-type and MOR-/- mice. Our results suggest that MOR signaling is not necessary for cannabinoid-mediated effects on feeding and that physiological antagonism of opioid receptor tone might be required for the observed synergistic effects of a CB1 inverse agonist and an opioid receptor antagonist on feeding.

Effects of mutations at conserved TM II residues on ligand binding and activation of mouse 5-HT6 receptor.

An aspartate residue (Asp-72) in the transmembrane helix II of mouse 5-hydroxytryptamine-6 receptor (5-HT6) is conserved among most G protein-coupled receptors. We have examined the functional significance of this residue by site-directed mutagenesis. A single Asp --> Ala (D72A) mutation resulted in an 8-fold decrease in apparent affinity for 5-HT, and a 60-fold reduction in EC50 value of agonist-induced stimulation of adenylyl cyclase. A F69L/T70I/D72A triple mutant showed a 2-fold reduction in apparent affinity for 5-HT but complete loss of adenylyl cyclase stimulation. Binding of SB-258585 (4-iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzene-sulfonamide), a selective 5-HT6 antagonist, was mildly affected (2- to 4-fold decrease in affinity) in the two mutants. Our data suggest that Asp-72 and additional residues toward the intracellular side of TM II have a limited role in ligand binding but are critical for functional activation of the 5-HT6 receptor.

Generation and characterization of a humanized bradykinin B1 receptor mouse.

Antagonists of the B1 bradykinin receptor (B1R), encoded by the BDKRB1 gene, offer the promise of novel therapeutic agents for inflammatory and neuropathic pain. However, the in vivo characterization of the pharmacodynamics of B1R antagonists is hindered by the low level of B1R expression in healthy tissue and the profound species selectivity exhibited by many compounds for the B1R. To circumvent these issues we generated two genetically engineered rodent models. The first is a transgenic rat over-expressing the human B1R under the control of the neuronal-specific enolase promoter; we previously reported the utility of this model in assessing human B1R receptor occupancy in the central nervous system of the rat. The second model, reported here, utilized gene-targeting by homologous recombination to replace the genomic coding sequence for the endogenous mouse B1R with that of the human B1R. The mRNA expression profile of the humanized Bdkrb1 (hBkdrb1) allele is similar to that of the mouse Bdkrb1 (mBkdrb1) in the wild-type animal. Furthermore, in vitro assays indicate that tissues isolated from the humanized mouse possess pharmacological properties characteristic of the human B1R. Therefore, we have generated a humanized B1R mouse model that is suitable for testing the efficacy of human B1R-selective compounds.

Chronic administration of nalmefene leads to increased food intake and body weight gain in mice.

Nalmefene is an orally available opioid receptor antagonist that has been shown to suppress appetite in humans, but its effects on chronic food intake and body weight remain unclear. Here, we report that chronic (21-day) oral administration of nalmefene at 2 or 10 mg/kg/day in diet-induced obese (DIO) mice led to significant increases (9-11%) in cumulative food intake. Mice in the nalmefene-treated groups also gained body weight at a rate faster than the control. Body composition analysis showed that the extra body weight gains in the treated animals were mostly due to increased fat accumulation. Since acute nalmefene treatment showed a trend toward a decrease rather than an increase in food intake, it is possible that the orexigenic effect of chronic oral administration of nalmefene was caused by pharmacologically active metabolites rather than the drug itself. Our results argue against the potential use of nalmefene for treating human obesity.

Synergistic effects of cannabinoid inverse agonist AM251 and opioid antagonist nalmefene on food intake in mice.

Oral administration of the opioid antagonist nalmefene alone (up to 20 mg/kg) failed to show a significant effect on acute food intake in mice. However, combined oral dosing of nalmefene and subthreshold doses of AM251, a cannabinoid CB1 receptor inverse agonist, led to a significant reduction in food intake in both lean and diet-induced obese (DIO) mice. Furthermore, the anorectic effect of a high dose of AM251 was further enhanced when co-administered with nalmefene. The results support a synergistic interaction between opioid and cannabinoid systems in regulating feeding behavior.

Transcriptional profiling of a mouse model for Rett syndrome reveals subtle transcriptional changes in the brain.

The Mecp2 gene has been shown to be mutated in most cases of human Rett syndrome, and mouse models deleted for the ortholog have been generated. Lineage-specific deletion of the gene indicated that the Rett-like phenotype is caused by Mecp2 deficiency in neurons. Biochemical evidence suggests that Mecp2 acts as a global transcriptional repressor, predicting that mutant mice should have genome-wide transcriptional deregulation. We tested this hypothesis by comparing global gene expression in wild-type and Mecp2 mutant mice. The results of numerous microarray analyses revealed no dramatic changes in transcription even in mice displaying overt disease symptoms, although statistical power analyses of the data indicated that even a small number of relatively subtle changes in transcription would have been detected if present. However, a classifier consisting of a combined small set of genes was able to distinguish between mutant and wild-type samples with high accuracy. This result suggests that Mecp2 deficiency leads to subtle gene expression changes in mutant brains which may be associated with the phenotypic changes observed.