A functional glutathione S-transferase P1 gene polymorphism is associated with methamphetamine-induced psychosis in Japanese population

Association of Glutathione Transferase M1, T1, P1 and A1 Gene Polymorphism and Susceptibility to IgA Vasculitis

Endothelial cell injury is a hallmark of IgA vasculitis (IgAV), possibly associated with various factors, including oxidative stress. Certain single nucleotide polymorphisms (SNPs) of glutathione S-transferases (GST) genes have been shown to increase susceptibility to oxidative stress. The objective of our study was to evaluate the gene polymorphisms of GSTM1, GSTT1, GSTP1, and GSTA1 in patients with IgAV. DNA was extracted from the blood of 124 children with IgAV and 168 age-matched healthy controls. A higher frequency of the GSTM1 null genotype was observed in patients with gastrointestinal (GI) system involvement compared to those without GI system involvement (51.5% vs. 28.6%, p = 0.011). Additionally, the GSTM1 null genotype was less prevalent (30.8% vs. 69.2%, p = 0.032), while the GSTP1 Val/Val genotype was significantly more prevalent in patients who developed urogenital complications (scrotal swelling) during the course of the disease (60% vs. 40%, p = 0.039). This study is the first to suggest an association between GSTM1 and GSTP1 polymorphisms and various phenotypes observed during the clinical course of IgAV in the pediatric population. However, it was performed on a national and likely single ethnic cohort, too small for definitive conclusions, so larger studies are needed to confirm this association.

Genetics of methamphetamine use disorder: A systematic review and meta-analyses of gene association studies

Genetic susceptibility to methamphetamine use disorder is poorly understood. No twin or adequately powered genome-wide association studies (GWASs) have been conducted. However, there are a large number of hypothesis-driven candidate gene association studies, which were systematically reviewed herein. Seventy-six studies were identified, investigating markers of 75 different genes. Allele frequencies, odds ratios, 95 % confidence intervals and power were calculated. Risk of bias was also assessed as a quality measure. Meta-analyses were conducted for gene markers if three or more studies were available. Eleven markers from adequately powered studies were significantly associated with methamphetamine use disorder, with Fatty Acid Amide Hydrolase (FAAH) and Brain Derived Neurotrophic Factor (BDNF) representing promising targets. Limitations of these studies include unclear rationale for candidate gene selection, low power and high risk of bias. Future research should include replications to enable more meta-analyses, well-powered GWASs or whole exome or genome sequencing, as well as twin and family studies to further complement the findings of this review to uncover genetic contributions toward methamphetamine use disorder.

Association Between Glutathione S-Transferase (GST) Polymorphisms and Schizophrenia in a Chinese Han Population

BACKGROUND

Glutathione S-transferase (GST) is an important antioxidant enzyme in the body. The weakening of the antioxidant system causes damage to the cells and tissues that make up the organism, adversely affects the function of the nervous system, and ultimately leads to schizophrenia (SCZ). Previous studies have yielded inconsistent results across different ethnic populations.

PURPOSE

This case-control study was carried out to investigate whether genetic polymorphisms in GST could be associated with SCZ in the Chinese Han population.

PATIENTS AND METHODS

A total of 794 participants, including 379 SCZ patients (case group) and 415 healthy individuals (control group), were genotyped by polymerase chain reaction-restriction fragment length for polymorphisms in GST genes.

RESULTS

The study found that the frequency of the GSTM1 null genotype was higher in case group than control group (p=0.003). The frequency of the GSTM1 and GSTT1 double null genotype was also higher in case group than control group (p=0.008).

CONCLUSION

We conclude that the GSTM1 null genotype and the GSTM1 and GSTT1 double null genotype may be related to the onset of SCZ in Chinese Han population.

Post-translational S-glutathionylation of cofilin increases actin cycling during cocaine seeking

Neuronal defense against oxidative damage is mediated primarily by the glutathione redox system. Traditionally considered a mechanism to protect proteins from irreversible oxidation, mounting evidence supports a role for protein S-glutathionylation in cell signaling in response to changes in intracellular redox status. Here we determined the specific sites on the actin binding protein cofilin that undergo S-glutathionylation. In addition, we show that S-glutathionylation of cofilin reduces its capacity to depolymerize F-actin. We further describe an assay to determine the S-glutathionylation of target proteins in brain tissue from behaving rodents. Using this technique, we show that cofilin in the rat nucleus accumbens undergoes S-glutathionylation during 15-minutes of cued cocaine seeking in the absence of cocaine. Our findings demonstrate that cofilin S-glutathionylation is increased in response to cocaine-associated cues and that increased cofilin S-glutathionylation reduces cofilin-dependent depolymerization of F-actin. Thus, S-glutathionylation of cofilin may serve to regulate actin cycling in response to drug-conditioned cues.

Association Between GSTP1 Ile105Val Genetic Polymorphism and Dependency to Heroin and Opium

Relationship between glutathione S-transferase P1 (GSTP1, OMIM: 134660) variants and the risk of drug dependency is unknown. Chronic use of illegal drugs leads to oxidative stress, which can be alleviated by cellular detoxification mechanisms. There are several polymorphisms in the GSTP1, including Ile105Val (rs1695). This polymorphism leads to an Ile105Val amino acid change and may alter the GSTP1 enzyme activity. There is no study on the association between this polymorphism and risks of heroin (HD) or opium (OD) dependency. This paper consists of two case-control studies. The first study consisted of 442 HD subjects and 794 healthy controls. The second study consisted of 143 cases with OD and 565 healthy blood donors as controls. Genotyping were carried out using PCR based method. The Ile/Val (OR 0.84, 95% CI 0.65-1.07, P = 0.165) and Val/Val (OR 0.87, 95% CI 0.56-1.36, P = 0.879) genotypes did not show significant association with the risk of HD. Neither the Ile/Val (OR 0.72, 95% CI 0.49-1.06, P = 0.103) nor the Val/Val (OR 0.61, 95% CI 0.29-1.30, P = 0.209) was associated with the risk of OD. The GSTP1 Ile105Val polymorphism was not associated with the risk of dependency to opium and heroin.

MicroRNA expression signature of methamphetamine use and addiction in the rat nucleus accumbens

Methamphetamine (METH) is a highly addictive psycho-stimulant that induces behavioral changes due to high level of METH-induced dopamine in the brain. Nucleus accumbens (NAc) plays an important role in these changes, especially in drug addiction. However, little is known about the underlying molecular mechanisms of METH-induced addiction. The objective of this study was to establish a behavioral model of METH use and addiction using escalating doses of METH over 15 days and to determine the global miRNA expression profiling in NAc of METH-addicted rats. In the behavioral study, the experimental rats were divided into 3 groups of 9 each: a control group, a single dose METH (5 mg/kg) treatment group and a continuous 15 alternate days METH (0.25, 0.5, 1, 2, 3, 4, 5 mg/kg) treatment group. Following that, six rats in each group were randomly selected for global miRNA profiling. Addiction behavior in rats was established using Conditioned Place Preference task. The analysis of the miRNA profiling in the NAc was performed using Affymetric microarray GeneChip® System. The findings indicated that a continuous 15 alternate days METH treatment rats showed a preference for the drug-paired compartment of the CPP. However, a one-time acute treatment with 5 mg/kg METH did not show any significant difference in preference when compared with controls. Differential profiling of miRNAs indicated that 166 miRNAs were up-regulated and 4 down-regulated in the chronic METH-treatment group when compared to controls. In comparing the chronic treatment group with the acute treatment group, 52 miRNAs were shown to be up-regulated and 7 were down-regulated. MiRNAs including miR-496-3p, miR-194-5p, miR-200b-3p and miR-181a-5p, were found to be significantly associated with METH addiction. Canonical pathway analysis revealed that a high number of METH addiction-related miRNAs play important roles in the MAPK, CREB, G-Protein Couple Receptor and GnRH Signaling pathways. Our results suggest that dynamic changes occur in the expression of miRNAs following METH exposure and addiction.

Biochemical Diagnosis in Substance and Non-substance Addiction

An optimal biochemical marker for addiction would be some easily traced molecules in body specimens, which indicates indulgent addictive behaviors, or susceptibility to certain addictive stimuli. In this chapter, we discussed existing literature about possible biomarkers, and classified them into three categories: origin forms and metabolites of substances, markers from biochemical responses to certain addiction, and genetic and epigenetic biomarkers suggesting susceptibility to addiction. In every category, we examined studies concerning certain type of addiction one by one, with focuses mainly on opiates, psychostimulants, and pathological gambling. Several promising molecules were highlighted, including those of neurotrophic factors, inflammatory factors, and indicators of vascular injury, and genetic and epigenetic biomarkers such as serum miRNAs. DNA methylation signatures and signal nucleotide polymorphism of candidate gene underlying the addiction.

S-Glutathionylation and Redox Protein Signaling in Drug Addiction

Drug addiction is a chronic relapsing disorder that comes at a high cost to individuals and society. Therefore understanding the mechanisms by which drugs exert their effects is of prime importance. Drugs of abuse increase the production of reactive oxygen and nitrogen species resulting in oxidative stress. This change in redox homeostasis increases the conjugation of glutathione to protein cysteine residues; a process called S-glutathionylation. Although traditionally regarded as a protective mechanism against irreversible protein oxidation, accumulated evidence suggests a more nuanced role for S-glutathionylation, namely as a mediator in redox-sensitive protein signaling. The reversible modification of protein thiols leading to alteration in function under different physiologic/pathologic conditions provides a mechanism whereby change in redox status can be translated into a functional response. As such, S-glutathionylation represents an understudied means of post-translational protein modification that may be important in the mechanisms underlying drug addiction. This review will discuss the evidence for S-glutathionylation as a redox-sensing mechanism and how this may be involved in the response to drug-induced oxidative stress. The function of S-glutathionylated proteins involved in neurotransmission, dendritic spine structure, and drug-induced behavioral outputs will be reviewed with specific reference to alcohol, cocaine, and heroin.

Animal models of gene-environment interaction in schizophrenia: A dimensional perspective

Schizophrenia has long been considered as a disorder with multifactorial origins. Recent discoveries have advanced our understanding of the genetic architecture of the disease. However, even with the increase of identified risk variants, heritability estimates suggest an important contribution of non-genetic factors. Various environmental risk factors have been proposed to play a role in the etiopathogenesis of schizophrenia. These include season of birth, maternal infections, obstetric complications, adverse events at early childhood, and drug abuse. Despite the progress in identification of genetic and environmental risk factors, we still have a limited understanding of the mechanisms whereby gene-environment interactions (G × E) operate in schizophrenia and psychoses at large. In this review we provide a critical analysis of current animal models of G × E relevant to psychotic disorders and propose that dimensional perspective will advance our understanding of the complex mechanisms of these disorders.

Glutathione and redox signaling in substance abuse

Throughout the last couple decades, the cause and consequences of substance abuse has expanded to identify the underlying neurobiological signaling mechanisms associated with addictive behavior. Chronic use of drugs, such as cocaine, methamphetamine and alcohol leads to the formation of oxidative or nitrosative stress (ROS/RNS) and changes in glutathione and redox homeostasis. Of importance, redox-sensitive post-translational modifications on cysteine residues, such as S-glutathionylation and S-nitrosylation could impact on the structure and function of addiction related signaling proteins. In this commentary, we evaluate the role of glutathione and redox signaling in cocaine-, methamphetamine- and alcohol addiction and conclude by discussing the possibility of targeting redox pathways for the therapeutic intervention of these substance abuse disorders.

Toxicity of amphetamines: an update

Amphetamines represent a class of psychotropic compounds, widely abused for their stimulant, euphoric, anorectic, and, in some cases, emphathogenic, entactogenic, and hallucinogenic properties. These compounds derive from the β-phenylethylamine core structure and are kinetically and dynamically characterized by easily crossing the blood-brain barrier, to resist brain biotransformation and to release monoamine neurotransmitters from nerve endings. Although amphetamines are widely acknowledged as synthetic drugs, of which amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are well-known examples, humans have used natural amphetamines for several millenniums, through the consumption of amphetamines produced in plants, namely cathinone (khat), obtained from the plant Catha edulis and ephedrine, obtained from various plants in the genus Ephedra. More recently, a wave of new amphetamines has emerged in the market, mainly constituted of cathinone derivatives, including mephedrone, methylone, methedrone, and buthylone, among others. Although intoxications by amphetamines continue to be common causes of emergency department and hospital admissions, it is frequent to find the sophism that amphetamine derivatives, namely those appearing more recently, are relatively safe. However, human intoxications by these drugs are increasingly being reported, with similar patterns compared to those previously seen with classical amphetamines. That is not surprising, considering the similar structures and mechanisms of action among the different amphetamines, conferring similar toxicokinetic and toxicological profiles to these compounds. The aim of the present review is to give an insight into the pharmacokinetics, general mechanisms of biological and toxicological actions, and the main target organs for the toxicity of amphetamines. Although there is still scarce knowledge from novel amphetamines to draw mechanistic insights, the long-studied classical amphetamines-amphetamine itself, as well as methamphetamine and MDMA, provide plenty of data that may be useful to predict toxicological outcome to improvident abusers and are for that reason the main focus of this review.

Methamphetamine-associated psychosis

Methamphetamine (METH) is a frequent drug of abuse in U.S. populations and commonly associated with psychosis. This may be a factor in frequent criminal justice referrals and lengthy treatment required by METH users. Persecutory delusions and auditory hallucinations are the most consistent symptoms of METH-associated psychosis (MAP). MAP has largely been studied in Asian populations and risk factors have varied across studies. Duration, frequency and amount of use as well as sexual abuse, family history, other substance use, and co-occurring personality and mood disorders are risk factors for MAP. MAP may be unique with its long duration of psychosis and recurrence without relapse to METH. Seven candidate genes have been identified that may be associated with MAP. Six of these genes are also associated with susceptibility, symptoms, or treatment of schizophrenia and most are linked to glutamatergic neurotransmission. Animal studies of pre-pulse inhibition, attenuation of social interaction, and stereotypy and alterations in locomotion are used to study MAP in rodents. Employing various models, rodent studies have identified neuroanatomical and neurochemical changes associated with METH use. Throughout this review, we identify key gaps in our understanding of MAP and suggest potential directions for future research.

Oxidative stress in schizophrenia: an integrated approach

Oxidative stress has been suggested to contribute to the pathophysiology of schizophrenia. In particular, oxidative damage to lipids, proteins, and DNA as observed in schizophrenia is known to impair cell viability and function, which may subsequently account for the deteriorating course of the illness. Currently available evidence points towards an alteration in the activities of enzymatic and nonenzymatic antioxidant systems in schizophrenia. In fact, experimental models have demonstrated that oxidative stress induces behavioral and molecular anomalies strikingly similar to those observed in schizophrenia. These findings suggest that oxidative stress is intimately linked to a variety of pathophysiological processes, such as inflammation, oligodendrocyte abnormalities, mitochondrial dysfunction, hypoactive N-methyl-d-aspartate receptors and the impairment of fast-spiking gamma-aminobutyric acid interneurons. Such self-sustaining mechanisms may progressively worsen producing the functional and structural consequences associated with schizophrenia. Recent clinical studies have shown antioxidant treatment to be effective in ameliorating schizophrenic symptoms. Hence, identifying viable therapeutic strategies to tackle oxidative stress and the resulting physiological disturbances provide an exciting opportunity for the treatment and ultimately prevention of schizophrenia.

Preliminary evidence of ethnic divergence in associations of putative genetic variants for methamphetamine dependence

Research into the biological processes that increase susceptibility to methamphetamine dependence has been conducted primarily in Asian populations. Using a case-control design this study's purpose was to explore, among a population of methamphetamine-dependent Caucasians, six putative single nucleotide polymorphisms previously found to be associated with methamphetamine dependence in Asian populations. A total of 193 non-psychotic males (117 methamphetamine-dependent and 76 controls) were genotyped for variants located in six genes (AKT1, ARRB2, BDNF, COMT, GSTP1, OPRM1). Genotypic and allelic frequencies, odds ratios, and 95% confidence intervals were calculated. None of the putative gene associations was significantly replicated in our sample of Caucasian men. Effect size comparisons suggest a trend toward allelic divergence for arrestin beta 2 (ARRB2) and glutathione S-transferase P1 (GSTP1) and allelic convergence for brain-derived neurotrophic factor (BDNF). Results provide preliminary support for further exploration and validation of candidate single nucleotide polymorphisms (SNPs) for methamphetamine (METH) dependence reported among Asian populations across other ethnic/ancestral groups.

Pharmacogenetics of drug dependence: role of gene variations in susceptibility and treatment

Drug dependency is a highly prevalent mental health disorder that imposes a significant burden on those directly affected, health care systems, and society in general. There is substantial heritability in the susceptibility to drug addiction, which indicates that there are genetic risk factors. Variation in the human genome is abundant and can directly affect drug dependency phenotypes, for example, by altering the function of a gene product or by altering gene expression. Pharmacogenetic studies can assess the effects of genetic variation on the risk for a particular phenotype (e.g., being an alcoholic). In addition, pharmacogenetic variability in treatment efficacy and adverse reactions can be investigated to identify particular genetic variants associated with altered responses. This review highlights examples of genetic variations that are important in the development and maintenance of specific drug dependencies as well as those that affect the response to treatment.

Methamphetamine use parameters do not predict neuropsychological impairment in currently abstinent dependent adults

Methamphetamine (meth) abuse is increasingly of public health concern and has been associated with neurocognitive dysfunction. Some previous studies have been hampered by background differences between meth users and comparison subjects, as well as unknown HIV and hepatitis C (HCV) status, which can also affect brain functioning. We compared the neurocognitive functioning of 54 meth dependent (METH+) study participants who had been abstinent for an average of 129 days, to that of 46 demographically comparable control subjects (METH-) with similar level of education and reading ability. All participants were free of HIV and HCV infection. The METH+ group exhibited higher rates of neuropsychological impairment in most areas tested. Among meth users, neuropsychologically normal (n=32) and impaired (n=22) subjects did not differ with respect to self-reported age at first use, total years of use, route of consumption, or length of abstinence. Those with motor impairment had significantly greater meth use in the past year, but impairment in cognitive domains was unrelated to meth exposure. The apparent lack of correspondence between substance use parameters and cognitive impairment suggests the need for further study of individual differences in vulnerability to the neurotoxic effects of methamphetamine.

Genetic association studies of methamphetamine use disorders: A systematic review and synthesis

Efforts to understand the biological processes that increase susceptibility to methamphetamine (METH) use disorders (i.e., abuse, dependence, and psychosis) have uncovered several putative genotypic variants. However, to date a synthesis of this information has not been conducted. Thus, systematic searches of the current literature were undertaken for genetic-association studies of METH use disorders. Each gene's chromosomal location, function, and examined polymorphic markers were extracted. Frequencies, odds ratios and 95% confidence intervals for risk alleles, as well as sample size and power, were calculated. We uncovered 38 studies examining 39 genes, of which 18 were found to have a significant genotypic, allelic, and/or haplotypic association with METH use disorders. Three genes (COMT, DRD4, and GABRA1) were associated with METH abuse, nine (ARRB2, BDNF, CYP2D6, GLYT1, GSTM1, GSTP1, PDYN, PICK1, and SLC22A3) with METH dependence, two (AKT1 and GABRG2) with METH abuse/dependence, and four (DTNBP1, OPRM1, SNCA, and SOD2) with METH psychosis. Limitations related to phenotypic classification, statistical power, and potential publication bias in the current literature were noted. Similar to other behavioral, psychiatric, and substance use disorders, the genetic epidemiology of METH use disorders is complex and likely polygenic. National and international collaborative efforts are needed to increase the availability of large population-based samples and improve upon the power to detect genetic associations of small magnitude. Further, replication of the findings reviewed here along with further development of more rigorous methodologies and reporting protocols will aid in delineating the complex genetic epidemiology of METH use disorders.

Pharmacogenetic treatments for drug addiction: cocaine, amphetamine and methamphetamine

BACKGROUND

Pharmacogenetics uses genetic variation to predict individual differences in response to medications and holds much promise to improve treatment of addictive disorders.

OBJECTIVES

To review how genetic variation affects responses to cocaine, amphetamine, and methamphetamine and how this information may guide pharmacotherapy.

METHODS

We performed a cross-referenced literature search on pharmacogenetics, cocaine, amphetamine, and methamphetamine.

RESULTS

We describe functional genetic variants for enzymes dopamine-beta-hydroxylase (DbetaH), catechol-O-methyltransferase (COMT), and dopamine transporter (DAT1), dopamine D4 receptor, and brain-derived neurotrophic factor (BDNF). A single nucleotide polymorphism (SNP; C-1021T) in the DbetaH gene is relevant to paranoia associated with disulfiram pharmacotherapy for cocaine addiction. Individuals with variable number tandem repeats (VNTR) of the SLC6A3 gene 3'-untranslated region polymorphism of DAT1 have altered responses to drugs. The 10/10 repeat respond poorly to methylphenidate pharmacotherapy and the 9/9 DAT1 variant show blunted euphoria and physiological response to amphetamine. COMT, D4 receptor, and BDNF polymorphisms are linked to methamphetamine abuse and psychosis.

CONCLUSIONS

Disulfiram and methylphenidate pharmacotherapies for cocaine addiction are optimized by considering polymorphisms affecting DbetaH and DAT1 respectively. Altered subjective effects for amphetamine in DAT1 VNTR variants suggest a 'protected' phenotype.

SCIENTIFIC SIGNIFICANCE

Pharmacogenetic-based treatments for psychostimulant addiction are critical for successful treatment.

Association study between the genetic polymorphisms of glutathione-related enzymes and schizophrenia in a Japanese population

Several lines of evidence suggest that oxidative stress plays a role in the pathogenesis of schizophrenia, and that glutathione (GSH) plays a crucial role in antioxidant defense mechanisms. In this study, we performed association studies between GSH-related genes (GSTM1, GSTP1, GSTO1, GSTT1, GSTT2, GPX1, and GCLM) and schizophrenia in a Japanese population. The overall distributions of the genotypes and alleles of each gene were not different between schizophrenic patients and controls. Subjects with residual-type schizophrenia showed different distributions in the analysis of GSTM1 genotype and in the combination analysis of GSTs, GPX1, and GCLM genotypes although the small sample size should be considered as a limitation of this study. In addition, our findings revealed that there were large ethnic differences in the genotype distributions of those GSH-related genes. The present study suggests that GSH-related genes may not play a major role in the pathogenesis of schizophrenia in a Japanese population. However, a dysregulation of GSH metabolism may be one of the vulnerability factors contributing to the development of a certain type of schizophrenia, and it is likely that the ethnic background should be considered in further study for those GSH-related genes.

Short allele of 5-HTTLPR as a risk factor for the development of psychosis in Japanese methamphetamine abusers

Accumulating evidence suggests that genetic factors contribute to the vulnerability to methamphetamine (MAP) abuse and associated psychiatric symptoms. Chronic MAP abuse leads to psychosis, which may be of a transient or a prolonged type. Serotonergic dysfunction has been proposed as one of the contributory factors in the development of MAP psychosis. Our PET studies revealed that the serotonin transporter (5-HTT) density in global brain regions is significantly lower in MAP abusers. In this study, we examined the role of a functional polymorphism in the 5' flanking region of the 5-HTT gene (5-HTTLPR) in the development of MAP psychosis in a Japanese population. We analyzed DNA samples from 166 MAP patients (95 with transient and 71 with prolonged psychosis) and 197 age-, sex-, and geographic-origin-matched healthy controls. Patients were also subdivided according to the presence (n= 119) or absence (n= 148) of spontaneous relapse. We observed significant genotypic association of the 5-HTTLPR polymorphism with MAP psychosis (P= 0.022), particularly in patients who show prolonged psychosis. The frequency of the S allele in patients with prolonged psychosis was significantly higher than that of the controls (P= 0.045); it was further higher in patients with prolonged psychosis with spontaneous relapse (P= 0.004). 5-HTTLPR has been suggested to regulate the transcriptional activity of 5-HTT, with S alleles showing lesser transcriptional efficiency and also lower 5-HT(1A) receptor-binding potential. Prolonged MAP use, combined with the high frequency of 5-HTTLPR S-alleles, may lead to reduced 5-HTT levels and 5-HT(1A) receptor-binding potential in the brain, resulting in the dysfunction of the serotonergic system. Thus, we suggest a possible role for the 5-HTTLPR polymorphism in MAP psychosis.

Association study between polymorphisms in glutathione-related genes and methamphetamine use disorder in a Japanese population

Accumulating evidence suggests that oxidative stress plays a role in the mechanisms of action of methamphetamine (METH) in the brain. In the present study, we investigated the association between the genetic polymorphisms among glutathione (GSH)-related enzymes; glutathione S-transferases (GSTs) such as GSTT1 (Non-deletion/Null), GSTT2 (Met139Ile), GSTA1 (-69C/T), and GSTO1 (Ala140Asp); glutathione peroxidase 1 (GPX1) (Pro198Leu); and glutamate-cysteine ligase modifier (GCLM) subunit and METH use disorder in a Japanese population. Two hundred eighteen METH abusers and 233 healthy controls were enrolled in the study. There was a significant difference in GSTT1 genotype frequency between patients with METH psychosis and controls (P = 0.039, odds ratio: 1.52, 95% CI 1.03-2.24). Furthermore, the frequency (66.0%) of the GSTT1 null genotype among prolonged-type METH psychotic patients with spontaneous relapse was significantly higher (P = 0.025, odds ratio: 2.43, 95% CI 1.13-5.23) than that (44.4%) of transient-type METH psychotic patients without spontaneous relapse. However, there were no associations between the polymorphisms of other genes and METH abuse. The present study suggests that the polymorphism of the GSTT1 gene might be a genetic risk factor of the development of METH psychosis in a Japanese population.

Molecular genetics of addiction and related heritable phenotypes: genome-wide association approaches identify "connectivity constellation" and drug target genes with pleiotropic effects

Genome-wide association (GWA) can elucidate molecular genetic bases for human individual differences in complex phenotypes that include vulnerability to addiction. Here, we review (a) evidence that supports polygenic models with (at least) modest heterogeneity for the genetic architectures of addiction and several related phenotypes; (b) technical and ethical aspects of importance for understanding GWA data, including genotyping in individual samples versus DNA pools, analytic approaches, power estimation, and ethical issues in genotyping individuals with illegal behaviors; (c) the samples and the data that shape our current understanding of the molecular genetics of individual differences in vulnerability to substance dependence and related phenotypes; (d) overlaps between GWA data sets for dependence on different substances; and (e) overlaps between GWA data for addictions versus other heritable, brain-based phenotypes that include bipolar disorder, cognitive ability, frontal lobe brain volume, the ability to successfully quit smoking, neuroticism, and Alzheimer's disease. These convergent results identify potential targets for drugs that might modify addictions and play roles in these other phenotypes. They add to evidence that individual differences in the quality and quantity of brain connections make pleiotropic contributions to individual differences in vulnerability to addictions and to related brain disorders and phenotypes. A "connectivity constellation" of brain phenotypes and disorders appears to receive substantial pathogenic contributions from individual differences in a constellation of genes whose variants provide individual differences in the specification of brain connectivities during development and in adulthood. Heritable brain differences that underlie addiction vulnerability thus lie squarely in the midst of the repertoire of heritable brain differences that underlie vulnerability to other common brain disorders and phenotypes.

Oxidative stress in psychiatric disorders: evidence base and therapeutic implications

Oxidative stress has been implicated in the pathogenesis of diverse disease states, and may be a common pathogenic mechanism underlying many major psychiatric disorders, as the brain has comparatively greater vulnerability to oxidative damage. This review aims to examine the current evidence for the role of oxidative stress in psychiatric disorders, and its academic and clinical implications. A literature search was conducted using the Medline, Pubmed, PsycINFO, CINAHL PLUS, BIOSIS Preview, and Cochrane databases, with a time-frame extending to September 2007. The broadest data for oxidative stress mechanisms have been derived from studies conducted in schizophrenia, where evidence is available from different areas of oxidative research, including oxidative marker assays, psychopharmacology studies, and clinical trials of antioxidants. For bipolar disorder and depression, a solid foundation for oxidative stress hypotheses has been provided by biochemical, genetic, pharmacological, preclinical therapeutic studies and one clinical trial. Oxidative pathophysiology in anxiety disorders is strongly supported by animal models, and also by human biochemical data. Pilot studies have suggested efficacy of N-acetylcysteine in cocaine dependence, while early evidence is accumulating for oxidative mechanisms in autism and attention deficit hyperactivity disorder. In conclusion, multi-dimensional data support the role of oxidative stress in diverse psychiatric disorders. These data not only suggest that oxidative mechanisms may form unifying common pathogenic pathways in psychiatric disorders, but also introduce new targets for the development of therapeutic interventions.

Negative correlation between brain glutathione level and negative symptoms in schizophrenia: a 3T 1H-MRS study

Background

Glutathione (GSH), a major intracellular antioxidant, plays a role in NMDA receptor-mediated neurotransmission, which is involved in the pathophysiology of schizophrenia. In the present study, we aimed to investigate whether GSH levels are altered in the posterior medial frontal cortex of schizophrenic patients. Furthermore, we examined correlations between GSH levels and clinical variables in patients.

Methods and Findings

Twenty schizophrenia patients and 16 age- and gender-matched normal controls were enrolled to examine the levels of GSH in the posterior medial frontal cortex by using 3T SIGNA EXCITE ¹H-MRS with the spectral editing technique, MEGA-PRESS. Clinical variables of patients were assessed by the Global Assessment of Functioning (GAF), Scale for the Assessment of Negative Symptoms (SANS), Brief Psychiatric Rating Scale (BPRS), Drug-Induced Extra-Pyramidal Symptoms Scale (DIEPSS), and five cognitive performance tests (Word Fluency Test, Stroop Test, Trail Making Test, Wisconsin Card Sorting Test and Digit Span Distractibility Test). Levels of GSH in the posterior medial frontal cortex of schizophrenic patients were not different from those of normal controls. However, we found a significant negative correlation between GSH levels and the severity of negative symptoms (SANS total score and negative symptom subscore on BPRS) in patients. There were no correlations between brain GSH levels and scores on any cognitive performance test except Trail Making Test part A.

Conclusion

These results suggest that GSH levels in the posterior medial frontal cortex may be related to negative symptoms in schizophrenic patients. Therefore, agents that increase GSH levels in the brain could be potential therapeutic drugs for negative symptoms in schizophrenia.

Biological treatments for amfetamine dependence : recent progress

Amfetamine abuse has grown into a worldwide epidemic. Methamfetamine, a derivative of amfetamine made from readily accessible chemicals, has plagued the US since the 1960s, with an alarming recent surge in the numbers of those meeting the criteria for amfetamine abuse and dependence. We review this problem using a computerised literature search (PubMed 1964-2007) to summarise knowledge from animal and human studies about treatments for amfetamine dependence, while exploring the potential of pharmacogenetics to help uncover new treatment targets. Several promising therapeutic targets have come from animal models of reward, drug-taking behaviour and withdrawal. Although preclinical and selected clinical results have been promising, clinical studies have yielded inconsistent results. To improve these outcomes, pharmacogenetic studies may be used to identify candidate alleles that predict therapeutic response. Exciting preclinical findings and a steady progression of clinical results offer hope for the development of a treatment for amfetamine dependence.

Differential effects of the ascorbyl and tocopheryl derivative on the methamphetamine-induced toxic behavior and toxicity

A previous study showed that high doses of methamphetamine induce self-injurious behavior (SIB) in rodents. Furthermore, the combination of methamphetamine and morphine increased lethality in mice. We recently surmised that the rise in SIB and mortality induced by methamphetamine and/or morphine may be related to oxidative stress. The present study was designed to determine whether an antioxidant could inhibit SIB or mortality directly induced by methamphetamine and/or morphine. The SIB induced by 20mg/kg of methamphetamine was abolished by the administration of Na L-ascorbyl-2-phosphate (APS: 300 mg/kg), but not Na DL-alpha-tocopheryl phosphate (TPNa: 200mg/kg). In contrast, APS (300 mg/kg) and TPNa (200mg/kg) each significantly attenuated the lethality induced by methamphetamine and morphine. The present study showed that the signal intensity of superoxide adduct was increased by 20mg/kg of methamphetamine in the heart and lungs, and methamphetamine plus morphine tended to increase superoxide adduct in all of the tissues measured by ESR spin trap methods. Adduct signal induced in brain by methamphetamine administration increased in significance, but in mouse administrated methamphetamine plus morphine. There are differential effects of administration of methamphetamine and coadministration of methamphetamine plus morphine on adduct signal. These results suggest that APS and TPNa are effective for reducing methamphetamine-induced toxicity and/or toxicological behavior. While APS and TPNa each affected methamphetamine- and/or morphine-induced toxicology and/or toxicological behavior, indicating that both drugs have antioxidative effects, their effects differed.

The GSTP1 Gene Is a Susceptibility Gene for Childhood Asthma and the GSTM1 Gene Is a Modifier of the GSTP1 Gene

BACKGROUND

Bronchial asthma is a chronic airway disorder characterized by bronchial inflammation. Oxidative stress is a key component of inflammation. Glutathione S-transferase P1 (GSTP1), the abundant isoform of glutathione S-transferases (GSTs) in lung epithelium, plays a key role in cellular protection against oxidative stress. Several studies have shown that the GSTP1 geneis involved in the pathogenesis of asthma and a gene-gene interaction may occur within the GST gene superfamily.

METHODS

We screened single-nucleotide polymorphisms (SNPs) at the GSTP1 locus and performed an association study in the Japanese population using two independent case-control groups (group 1: 391 pediatric patients with asthma, 462 adult patients with asthma, and 639 controls, and group 2: 115 pediatric patients with asthma and 184 controls). The effect of GSTM1 null/present genotype on the association between GSTP1 Ile105Val and asthma was also investigated.

RESULTS

We identified 20 SNPs at this locus and found this region consisted of one linkage disequilibrium block represented by four SNPs (tag SNPs). The association between the Ile105Val polymorphism in the GSTP1 gene and childhood asthma was significant in both groups (p = 0.047 in group 1, and p = 0.021 in group 2). This association was only significant in patients with GSTM1-positive genotype in both groups (group 1: GSTM1 present p = 0.013 and GSTM1 null p = 0.925, and group 2: GSTM1 present p = 0.015 and GSTM1 null p = 0.362).

CONCLUSIONS

These findings suggest that the GSTP1 gene is a childhood asthma susceptible gene, and the GSTM1 gene is a modifier gene of GSTP1 for the risk of childhood asthma in the Japanese population.

Structure SNP (StSNP): a web server for mapping and modeling nsSNPs on protein structures with linkage to metabolic pathways

SNPs located within the open reading frame of a gene that result in an alteration in the amino acid sequence of the encoded protein [nonsynonymous SNPs (nsSNPs)] might directly or indirectly affect functionality of the protein, alone or in the interactions in a multi-protein complex, by increasing/decreasing the activity of the metabolic pathway. Understanding the functional consequences of such changes and drawing conclusions about the molecular basis of diseases, involves integrating information from multiple heterogeneous sources including sequence, structure data and pathway relations between proteins. The data from NCBI's SNP database (dbSNP), gene and protein databases from Entrez, protein structures from the PDB and pathway information from KEGG have all been cross referenced into the StSNP web server, in an effort to provide combined integrated, reports about nsSNPs. StSNP provides 'on the fly' comparative modeling of nsSNPs with links to metabolic pathway information, along with real-time visual comparative analysis of the modeled structures using the Friend software application. The use of metabolic pathways in StSNP allows a researcher to examine possible disease-related pathways associated with a particular nsSNP(s), and link the diseases with the current available molecular structure data. The server is publicly available at http://glinka.bio.neu.edu/StSNP/.

Symbiotic relationship of pharmacogenetics and drugs of abuse

Pharmacogenetics/pharmacogenomics is the study of how genetic variation affects pharmacology, the use of drugs to treat disease. When drug responses are predicted in advance, it is easier to tailor medications to different diseases and individuals. Pharmacogenetics provides the tools required to identify genetic predictors of probable drug response, drug efficacy, and drug-induced adverse events-identifications that would ideally precede treatment decisions. Drug abuse and addiction genetic data have advanced the field of pharmacogenetics in general. Although major findings have emerged, pharmacotherapy remains hindered by issues such as adverse events, time lag to drug efficacy, and heterogeneity of the disorders being treated. The sequencing of the human genome and high-throughput technologies are enabling pharmacogenetics to have greater influence on treatment approaches. This review highlights key studies and identifies important genes in drug abuse pharmacogenetics that provide a basis for better diagnosis and treatment of drug abuse disorders.

A GSTP1 functional variant associated with cocaine dependence in a Brazilian population

Cocaine dependence aetiology is complex and genetically influenced. We hypothesize that, for many users, efficient metabolism of cocaine and its toxic byproducts aids persistent cocaine use, such as that leading to dependence. The glutathione-S-transferases - in particular, GST-Pi - may be important in preventing cocaine and alcohol-induced oxidative damage. We genotyped a GST-Pi functional polymorphism (Ile105Val) in 654 male cocaine users and 572 controls from Brazil. Genotype and allele frequencies of Ile105Val differed significantly (chi = 6.74; P=0.03 and chi = 6.54; P = 0.01, respectively). Ile/Ile cocaine dependents had an OR = 1.31 (95%CI: 1.04-1.65), and Ile/Ile dependents consuming >50 units alcohol weekly an OR of 1.44 (95% CI:1.06-1.96). Population stratification was assessed and did not affect the results. These data require replication but do suggest that the high activity Ile105 GST-Pi allele may influence the aetiology and development of cocaine dependence.