catechol-O-methyltransferase Enzyme Activity Research Articles

Udruženost polimorfizama gena za katehol-Ometiltransferazu sa terapijskim odgovorom i komplikacijama izazvanim levodopom kod Parkinsonove bolesti - rezime sadašnjih saznanja

Catechol-O-methyltransferase (COMT) is one of the cardinal enzymes in the degradation of catecholamines and levodopa. Genetic variants of the COMT gene may affect COMT enzyme activity. The most examined COMT gene polymorphism is the nonsynonymous single nucleotide polymorphism (SNP) in exon 4 (Val108/158Met; rs4680). This highly functional polymorphism is responsible for fourfold variations in enzyme activity and Dopamine catabolism. Recent data suggested that even synonymous SNPs of the COMT gene can lead to changes in enzyme activity. Genetically determined COMT activity can affect an individual's response to levodopa therapy and carries the risk of complications from prolonged levodopa use in Parkinson's disease (PD) patients. Identifying at-risk individuals through genetic susceptibility markers could help to prevent the development of levodopa-induced complications in PD.

Estradiol and the Catechol-o-methyltransferase Gene Interact to Predict Working Memory Performance: A Replication and Extension.

Decades of evidence across taxa have established the importance of dopamine (DA) signaling in the pFC for successful working memory performance. Genetic and hormonal factors can shape individual differences in prefrontal DA tone. The catechol-o-methyltransferase (COMT) gene regulates basal prefrontal DA, and the sex hormone 17β-estradiol potentiates DA release. E. Jacobs and M. D'Esposito [Estrogen shapes dopamine-dependent cognitive processes: Implications for women's health. Journal of Neuroscience, 31, 5286-5293, 2011] investigated the moderating role of estradiol on cognition using the COMT gene and COMT enzymatic activity as a proxy for pFC DA tone. They found that increases in 17β-estradiol within women at two time points during the menstrual cycle influenced working memory performance in a COMT-dependent manner. Here, we aimed to replicate and extend the behavioral findings of Jacobs and D'Esposito by employing an intensive repeated-measures design across a full menstrual cycle. Our results replicated the original investigation. Within-person increases in estradiol were associated with improved performance on 2-back lure trials for participants with low basal levels of DA (Val/Val carriers). The association was in the opposite direction for participants with higher basal levels of DA (Met/Met carriers). Our findings support the role of estrogen in DA-related cognitive functions and further highlight the need to consider gonadal hormones in cognitive science research.

Catechol-O-Methyltransferase Effects on Smoking: A Review and Proof of Concept of Sex-Sensitive Effects.

This article reviews recent research on how catechol-O-methyltransferase (COMT) may impact cigarette smoking behavior, and how effects may be sex-sensitive. Preliminary data are presented on sex-sensitive effects of COMT on response to short-term abstinence in individuals who smoke. Although research is mixed, functional variants in the COMT gene have been linked with smoking behavior, cessation outcomes and nicotine abstinence-related symptoms. Our proof-of-concept preliminary data from a human laboratory study of individuals who smoke cigarettes found that those with the high COMT enzyme activity genotype (Val/Val) reported more severe smoking urges and withdrawal symptoms following overnight abstinence than Met carriers. These effects were present in women, but not in men and were abstinent-dependent, in that they dissipated following nicotine administration. The preliminary data showing sex-sensitive pharmacogenetic effects may shed light on mechanisms contributing to sex differences in barriers to smoking cessation or potential sex-specific treatment options.

Differential analyte derivatization enables unbiased MALDI-TOF-based high-throughput screening: A proof-of-concept study for the discovery of catechol-o-methyltransferase inhibitors.

Recent advances in label-free high-throughput screening via matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) offer unprecedented opportunities for the identification of novel chemical starting points in target-based drug discovery. A clear advantage of the technology is the possibility for label-free, direct quantification of analytes with high precision and robustness. Here we have expanded the range of analytes and biology that can be addressed via MALDI-TOF HTS, by developing a method based on post-reaction pyrylium-based derivatization to detect 3-methoxytyramine, the physiological enzyme product of the catechol-O-methyltransferase (COMT) enzyme. The introduction of pyrylium-type reagents as universal derivatization strategy under aqueous conditions for molecules containing primary amines represents a valuable addition to the toolbox of MALDI-TOF assay development. Characterization of COMT's enzymatic activity and inhibition by reference inhibitors, and comparison of the results obtained in our assay with data from previous mechanistic studies validated the performance of this new method. To address the problem of isobaric interference, a source of false results in MALDI-TOF assays measuring low molecular weight analytes, we devised a differential derivatization workflow which can potentially replace other counter- or orthogonal assays in future screening campaigns. Finally, we report on the first label-free HTS campaign for the identification of COMT inhibitors performed in miniaturized 1536-well microtiter plate format via MALDI-TOF MS analysis.

Effect of Catechol-O-Methyltransferase Genotype Polymorphism on Neurological and Psychiatric Disorders: Progressing Towards Personalized Medicine.

Different polymorphisms of the catechol-O-methyltransferase (COMT) gene affect the COMT enzyme activity. The COMT enzyme plays a major role in the pathophysiology of various neurological and psychiatric disorders. This review article aims to discuss what recent research has discovered about the association of COMT genotype polymorphism with neurological and psychiatric disorders and the scope for the knowledge to be applied for advancement in therapeutics. We searched PubMed and Google Scholar databases and found 1656 articles. We included observational studies, clinical trials, and meta-analyses in the English language published between 2019 and 2021. We screened the articles based on the title and the abstract and found 26 relevant articles. Diseases or conditions studied primarily were schizophrenia, Parkinson’s disease, Alzheimer’s disease, substance use, and depression. This article highlights how genetics influences the susceptibility of an individual to neurological and psychiatric diseases and the variations in the specific symptoms of those diseases. The review showed that the variability in individual response to therapeutic interventions stems from the gene level. This knowledge can contribute towards the dawn of a new era of personalized medicine.

Genetic variation in catechol-O-methyltransferase is associated with individual differences in conditioned pain modulation in healthy subjects.

Genetic variation in the catechol-O-methyltransferase (COMT) gene is associated with sensitivity to both acute experimental pain and chronic pain conditions. Four single nucleotide polymorphisms (SNPs) have traditionally been used to infer three common haplotypes designated as low, average and high pain sensitivity and are reported to affect both COMT enzymatic activity and pain sensitivity. One mechanism that may partly explain individual differences in sensitivity to pain is conditioned pain modulation (CPM). We hypothesized that variation in CPM may have a genetic basis. We evaluated CPM in 77 healthy pain-free Caucasian subjects by applying repeated mechanical stimuli to the dominant forearm using 26-g von Frey filament as the test stimulus with immersion of the non-dominant hand in hot water as the conditioning stimulus. We assayed COMT SNP genotypes by the TaqMan method using DNA extracted from saliva. SNP rs4680 (val158 met) was not associated with individual differences in CPM. However, CPM was associated with COMT low pain sensitivity haplotypes under an additive model (p = 0.004) and the effect was independent of gender. We show that, although four SNPs are used to infer COMT haplotypes, the low pain sensitivity haplotype is determined by SNP rs6269 (located in the 5' regulatory region of COMT), suggesting that inherited variation in gene expression may underlie individual differences in pain modulation. Analysis of 13 global populations revealed that the COMT low pain sensitivity haplotype varies in frequency from 13% to 44% and showed that two SNPs are sufficient to distinguish all COMT haplotypes in most populations.

Population pharmacokinetics of levodopa gel infusion in Parkinson\u2019s disease: effects of entacapone infusion and genetic polymorphism

Levodopa-entacapone-carbidopa intestinal gel (LECIG) provides continuous drug delivery through intrajejunal infusion. The aim of this study was to characterize the population pharmacokinetics of levodopa following LECIG and levodopa-carbidopa intestinal gel (LCIG) infusion to investigate suitable translation of dose from LCIG to LECIG treatment, and the impact of common variations in the dopa-decarboxylase (DDC) and catechol-O-methyltransferase (COMT) genes on levodopa pharmacokinetics. A non-linear mixed-effects model of levodopa pharmacokinetics was developed using plasma concentration data from a double-blind, cross-over study of LCIG compared with LECIG in patients with advanced Parkinson’s disease (n = 11). All patients were genotyped for rs4680 (polymorphism of the COMT gene), rs921451 and rs3837091 (polymorphisms of the DDC gene). The final model was a one compartment model with a high fixed absorption rate constant, and a first order elimination, with estimated apparent clearances (CL/F), of 27.9 L/h/70 kg for LCIG versus 17.5 L/h/70 kg for LECIG, and apparent volume of distribution of 74.4 L/70 kg. Our results thus suggest that the continuous maintenance dose of LECIG, on a population level, should be decreased by approximately 35%, to achieve similar drug exposure as with LCIG. An effect from entacapone was identified on all individuals, regardless of COMT rs4680 genotype. The individuals with higher DDC and COMT enzyme activity showed tendencies towards higher levodopa CL/F. The simultaneous administration of entacapone to LCIG administration results in a 36.5% lower apparent levodopa clearance, and there is a need for lower continuous maintenance doses, regardless of patients’ COMT genotype.

Evidence from stable-isotope labeling that catechol is an intermediate in salicylic acid catabolism in the flowers of Silene latifolia (white campion)

Main conclusionA stable isotope-assisted mass spectrometry-based platform was utilized to demonstrate that the plant hormone, salicylic acid, is catabolized to catechol, a widespread secondary plant compound.The phytohormone salicylic acid (SA) plays a central role in the overall plant defense program, as well as various other aspects of plant growth and development. Although the biosynthetic steps toward SA are well documented, how SA is catabolized in plants remains poorly understood. Accordingly, in this study a series of stable isotope feeding experiments were performed with Silene latifolia (white campion) to explore possible routes of SA breakdown. S. latifolia flowers that were fed a solution of [2H6]-salicylic acid emitted the volatile and potent pollinator attractant, 1,2-dimethoxybenzene (veratrole), which contained the benzene ring-bound deuterium atoms. Extracts from these S. latifolia flowers revealed labeled catechol as a possible intermediate. After feeding flowers with [2H6]-catechol, the stable isotope was recovered in veratrole as well as its precursor, guaiacol. Addition of a trapping pool of guaiacol in combination with [2H6]-salicylic acid resulted in the accumulation of the label into catechol. Finally, we provide evidence for catechol O-methyltransferase enzyme activity in a population of S. latifolia that synthesizes veratrole from guaiacol. This activity was absent in non-veratrole emitting flowers. Taken together, these results imply the conversion of salicylic acid to veratrole in the following reaction sequence: salicylic acid > catechol > guaiacol > veratrole. This catabolic pathway for SA may also be embedded in other lineages of the plant kingdom, particularly those species which are known to accumulate catechol.

Chronic persistent surgical pain is strongly associated with COMT alleles in patients undergoing cardiac surgery with median sternotomy.

Catechol-O-methyl transferase (COMT), a catechol-dependent enzyme, plays pivotal role in the development of pain. In different ethnic populations, it is associated with chronic persistent surgical pain (CPSP). In this context, the present study is aimed to assess involvement of COMT allele (Val158Met) in the development of CPSP. The patients (n = 216) underwent cardiac surgery with median sternotomy were selected to assess the magnitude of the CPSP evaluated with pain questionnaires' after 3months from surgery. The exon 4 of COMT gene was PCR amplified and sequenced. The quantitative gene expression of COMT using RT-PCR corroborated the COMT enzyme activity. Among 216 patients who underwent sternotomy procedure, 54 patients showed CPSP even after 3months from surgery. The sequence analysis revealed that, in 25% (54/216) patients having following one or more alleles: c.472G>A (Val158Met) (reported), and novel c.382C>G;c.383G>C (Arg128Ala), c.373C>G (Arg125Gly), c.370G>A (Val124Met), c.359G>C (Gly120Ala), c.349G>A, c.350G>A(Ala117Ser), c.349G>C, c.351C>A (Ala117Pro), c.349G>A (Ala117Thr), c.350G>C (Ala117Gly), and c.405G>C (Ala135Ser) were observed for the first time in Indian population. Distinct CPSP (≥ 4 NRS pain score) was observed in these patients correlating with COMT enzyme activity (7.80 ± 0.92 units/mg) which is 14 times lowered when compared with non-CPSP patient's (n = 162) 110.15 ± 6.41units/mg. The findings of COMT gene expression using quantitative RT-PCR corroborated the COMT enzyme activity. The dominant effect of mutant COMT alleles connecting with low enzyme activity resulted in CPSP, warrants COMT genetic analysis prior to surgery was useful to predict the occurrence of CPSP.

Profesyonel Voleybolcularda Katekol-O-Metiltransferaz (COMT) rs4680 Polimorfizminin Belirlenmesi

Catechol-O-Methyl Transferase (COMT) is involved in the inactivation of catecholamine neurotransmitters (dopamine, epinephrine, norepinephrine). The discovered functional polymorphisms in the COMT gene are known to cause changes in COMT enzyme activity. In our study, the Val (108/158) Met rs4680 polymorphism of the COMT gene was examined in professional volleyball players and it was aimed to determine the genotype and allele distributions of COMT rs4680 polymorphism in volleyball players. In this context, 21 professional volleyball athletes participated in our study. The genotyping study was completed with real-time polymerase chain reaction (RT-PCR) after swab DNA isolation. According to the results of our study, AA, AG and GG genotype distributions in our athletes; In 6 of our athletes (29%), 7 of our athletes (33%) had GA and 8 of our athletes (38%) had AA genotype. When we look at the allel numbers of our volleyball players, G Allele was 19 (45%) and A Allele 23 (55%). AA genotype in our cohort was higher than other genotypes, compared to A allele G allele. According to our findings, volleyball athletes’ low activity AA genotype has been proved to be a biomarker for predisposition to volleyball sport. Our study is the first research to examine the effect of COMT rs4680 polymorphism on volleyball players.

Estrogen down regulates COMT transcription via promoter DNA methylation in human breast cancer cells

Catechol-O-methyltransferase (COMT) acts as a ‘gate-keeper’ to prevent DNA damage during estrogen metabolism. Both experimental and epidemiological studies suggest the role of COMT in pathogenesis of human breast cancer (BCa). It was previously reported that inhibition of COMT enzyme activity in estradiol-treated human breast epithelial carcinoma-derived MCF-7 cells caused increased oxidative DNA damage and formation of mutagenic depurinating adducts. To improve our understanding of factors influencing estrogen metabolism in BCa, it requires a mechanistic study illustrating the regulation of this ‘gate-keeper’. We investigated the epigenetic mechanisms underlying decreased COMT transcription in MCF-7 cells exposed to 17ß-estradiol (E2) and the phytoestrogen, genistein (GEN). CpG site-specific methylation at promoters for both soluble (S) and membrane-bound (MB) COMT transcripts were assessed. Both E2 and GEN induced CpG site-specific methylation within the distal promoter of MB-COMT. In addition, ChIP analysis showed that there was increased binding of DNMT3B, MBD2 and HDAC1 within this promoter. These epigenetic changes were associated with decreased COMT transcript levels. Interestingly, sulforaphane, an antioxidant commonly found in cruciferous vegetables, was able to reverse the estrogen-induced epigenetic changes and gene silencing of COMT. Our data provide a new insight in epigenetically targeting COMT transcription. Since reactive estrogen metabolites may contribute to breast cancer, our findings may help in developing prevention and/or intervention strategies for human BCa.

Catechol-O-Methyltransferase Val158Met and brain-derived neurotrophic factor Val66Met gene polymorphisms in paraphilic sexual offenders.

Background:Child sexual abuse (CSA) is an important problem worldwide. The reason of sex abuse is considered as multifactorial. Genetic contribution reported by recent studies is a significant evidence for this pathologic behavior. Catechol-O-Methyltransferase (COMT) is an enzyme in the metabolic inactivation of catecholamine and substances containing catecholamines such as dopamine, epinephrine, and norepinephrine. COMT polymorphism causes functional changes in COMT enzyme activity. Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor usually synthesized from central nervous system neurons. With the effect of BDNF, dopamine and serotonin play important roles on neurogenesis, survival, and synaptic plasticity.Aim:This study aims to examine COMT Val158Met (rs4680) and BDNF Val66Met (rs6265) polymorphisms in CSA.Settings and Design:This was a case–control study.Materials and Methods:Seventy paraphilic child sexual abuser patients and seventy age- and gender-matched healthy controls participated in this study. COMT Val158Met and BDNF Val66Met polymorphisms were genotyped by real-time polymerase chain reaction assay.Results:COMT Val158Met genotype frequencies were determined as GG 31.4%, GA 45.7%, and AA 22.9% in patients; GG 24.3%, GA 45.7%, and AA 8.6% in controls; and exhibited a positive relationship between the groups (P = 0.018). BDNF Val66Met genotype frequencies were determined as GG 77.1%, GA 21.4%, and AA 1.4% in patients; GG 65.7%, GA 31.4%, AA 2.9% in controls; and no significant relationship was observed between the groups (P = 0.317).Conclusions:This research investigated COMT (Val158Met) and BDNF (Val66Met) in paraphilic child sexual offenders. A positive relationship was found for COMT gene; however, no significant relation was observed for BDNF gene between paraphilic sexual offenders and controls.

Potential Impact of COMT-rs4680 G > A Gene Polymorphism in Coronary Artery Disease.

Purpose: Catechol-O-methyltransferase (COMT) plays a central role in DNA repair and estrogen-induced carcinogenesis. The nonsynonymous single nucleotide polymorphism (SNP) in exon 4 G > A or Val108 > 158Met or rs4680 G > A influences COMT enzyme activity. The three phenotypes of the COMT enzyme activities include COMT A/A with low enzyme activity, COMT A/G with medium enzyme activity and COMT G/G with high enzyme activity. The Met allele is associated with low enzymatic activity resulting in higher levels of prefrontal dopamine. Conversely, the Val allele is associated with high enzymatic activity and lower levels of prefrontal dopamine. The Met allele has been associated with several psychiatric disorders such as panic disorder. Many recent epidemiologic studies have investigated the association between the COMT Val158Met polymorphism and coronary artery diseases risk, but the results are inconclusive. Therefore our study was aimed to explore the association between COMT Val158Met polymorphism and the risk of coronary artery disease in India. Methology: This study was conducted on 100 clinically confirmed cases of coronary artery diseases and 100 healthy controls. COMT Val158Met genotyping was performed by allele-specific polymerase chain reaction (AS-PCR). Results: A significant correlation was observed in the COMT Val158Met genotype distribution between the coronary artery disease cases and healthy controls (p = 0.008). The frequencies of all three genotypes, GG, GA, AA, reported in the CAD patients were 10%, 70%, and 20%, and 30%, 60%, and 10% in the healthy controls respectively. An increased risk of coronary artery disease was observed in the codominant inheritance model for COMT-GA vs. GG genotype with an OR of 3.5, 95% CI (1.58–7.74) p = 0.002) and COMT-AA vs. GG genotype with an OR of 6.0 95% CI (2.11–17.3) p = 0.003). The higher risk of coronary artery disease was observed in the dominant inheritance model for COMT (GA + AA) vs. GG genotype (OR 3.85, 95% CI 1.76–8.4, p < 0.007), whereas a non-significant association was found in recessive model for COMT (GG + GA vs. AA) (OR = 2.01, 95% CI (0.86–4.7) p = 0.72). The results indicated that A allele significantly increased the risk of coronary artery disease compared to the G allele (OR = 1.8, 95% CI (1.20–2.67) p = 0.004). COMT Val158Met polymorphism leads to a 6.0, 3.5 and 1.8-fold increased risk of developing coronary artery disease in the Indian population and providing novel insights into the genetic etiology and underlying biology of coronary artery disease. Conclusions: It is concluded that COMT-AA genotype and A allele are significantly associated with an increased susceptibility to coronary artery disease in Indian population. A larger sample size can be the key to progress in establishing the genetic co-relationship of COMT polymorphism and cardiovascular disease.

Catechol-O-methyltransferase (COMT) genotype affects cognitive control during total sleep deprivation

Adaptive decision making is profoundly impaired by total sleep deprivation (TSD). This suggests that TSD impacts fronto-striatal pathways involved in cognitive control, where dopamine is a key neuromodulator. In the prefrontal cortex (PFC), dopamine is catabolized by the enzyme catechol-O-methyltransferase (COMT). A functional polymorphism (Val158Met) influences COMT's enzymatic activity, resulting in markedly different levels of prefrontal dopamine. We investigated the effect of this polymorphism on adaptive decision making during TSD. Sixty-six healthy young adults participated in one of two in-laboratory studies. After a baseline day, subjects were randomized to either a TSD group (n = 32) with 38 h or 62 h of extended wakefulness or a well-rested control group (n = 34) with 10 h nighttime sleep opportunities. Subjects performed a go/no-go reversal learning (GNGr) task at well-rested baseline and again during TSD or equivalent control. During the task, subjects were required to learn stimulus–response relationships from accuracy feedback. The stimulus–response relationships were reversed halfway through the task, which required subjects to learn the new stimulus–response relationships from accuracy feedback. Performance on the GNGr task was quantified by discriminability (d′) between go and no-go stimuli before and after the stimulus–response reversal. GNGr performance did not differ between COMT genotypes when subjects were well-rested. However, TSD exposed a significant vulnerability to adaptive decision making impairment in subjects with the Val allele. Our results indicate that sleep deprivation degrades cognitive control through a fronto-striatal, dopaminergic mechanism.

Roles of functional catechol-O-methyltransferase genotypes in Chinese patients with Parkinson\u2019s disease

BackgroundRecent studies have found that the functional catechol-O-methyltransferase (COMT) gene may be associated with the susceptibility to and pharmacotherapy of Parkinson’s disease (PD). In this case–control study, we investigated the most common functional COMT gene haplotypes that had been shown to influence COMT enzymatic activity and the association of the single and combined COMT haplotypes with clinical symptoms and pharmacotherapy in Chinese patients with PD.MethodsOne hundred forty-three patients with idiopathic PD and 157 healthy individuals were enrolled in this study. Four single nucleotide polymorphisms (SNPs) in the COMT gene (formed by SNPs) were genotyped in each participant: rs6269 A > G; rs4633 C > T; rs4818 C > G; and rs4680 G > A.ResultsThe frequencies of rs4633 T carriers, rs4680 A carriers and the two linked rs4633-rs4680 T/A carriers were significantly higher in the early onset PD group than in the healthy controls (all P < 0.05). Homozygosity for rs4633 (TT), rs4680 (AA) and of the two linked rs4633-rs4680 (TT/AA) was significantly more frequent in patients who exhibited the “wearing-off” phenomenon, longer disease duration, higher levodopa equivalent doses (LED) and higher Unified Parkinson’s Disease Rating Scale (UPDRS) scores (P < 0.05). No significant differences were observed in the clinical features of patients who carried individual rs6269 and rs4818, the two linked rs6269-rs4818 and the four combined COMT SNPs.ConclusionsThe results showed a possible association of combined functional COMT SNPs with PD risk, disease duration, the “wearing-off” phenomenon, daily LEDs and higher UPDRS scores, which may be useful in instituting individualized therapy for patients with PD.

Dopamine dysfunction in 22q11 deletion syndrome: possible cause of motor symptoms.

22q11 Deletion syndrome (22q11DS) is a neurogenetic disorder, resulting from a hemizygous microdeletion on the long arm of chromosome 22. In 22q11DS, the phenotypic expression is highly variable. Approximately one-third of all individuals with 22q11DS develop schizophrenia-like psychotic disorder. Among the genes in the deleted region, catechol-O-methyltransferase (COMT) has a particular relevance for psychiatric disorders: lower COMT enzymatic activity decreases the clearance of dopamine (DA), yielding higher levels of catecholamines in the central nervous system. Deficits in myelinogenesis and dysfunctions in the DA system could justify the white matter abnormalities in motor/premotor circuits described in 22q11DS. The alterations in DA could determine the high incidence of psychiatric disorders and the presence of neurological soft signs in 22q11DS. Neurological soft signs are defined as non-normative performance on an examination of motor and sensory tasks without focal neurological deficits. COMT haploinsufficiency, DA dysfunction, and white matter abnormalities may contribute toward the presence of neurological soft signs in 22q11DS.

No association of Catechol-O-Methyltransferase (COMT) Gene Haplotypes in Patients with Schizophrenia in a Turkish Sample

Objective: The dopaminergic system, especially variations in the catechol-O-methyltransferase (COMT) gene, is of major interest in the etiology of schizophrenia. The rs4680 (Val108/158Met), rs165599, and P2 promoter rs2075507 single nucleotide polymorphisms (SNPs) in the COMT gene have been shown to be associated with alteration of COMT gene expression and COMT enzyme activity. The aim of this study was to investigate a possible association between schizophrenia and the haplotypes of these polymorphisms.Methods: The sample was comprised of 181 patients with schizophrenia and 368 healthy controls. The patients' psychotic symptoms were rated using the Positive and Negative Symptom Scale (PANSS). COMT rs2075507, rs4680, and rs165599 SNPs were evaluated by a polymerase chain reaction, followed by restriction fragment length polymorphism analysis. These SNPs in the COMT gene were subjected to haplotype analyses using Haploview ver. 4.2.Results: No significant differences were found between COMT rs2075507, rs4680, and rs165599 SNPs in schizophrenic patients and controls. The patients' PANSS results were not associated with these SNPs. No associations were obtained between 2 and 3-haplotypes of rs2075507, rs4680, rs165599 SNPs and schizophrenia.Conclusion: COMT rs2075507, rs4680, rs165599 SNPs and haplotypes do not appear to be risk factors for schizophrenia in this population.

Lack of association between catechol-Omethyltransferase and schizophrenia in a Turkish population

Abstract Objective: Catechol-O-methyltransferase (COMT) is the key molecule in the catabolism of catecholamines like dopamine which is an important molecule in schizophrenia. Due to its function and location COMT gene is a strong candidate gene for schizophrenia. The aim of this study was to investigate the possible associations of 3 COMT single nucleotide polymorphisms (SNPs) and schizophrenia in our population. COMT enzyme activity is regulated by a widely known Val158Met polymorphism (rs4680), along with the variation of the SNPs rs737865 and rs165599. Methods: Val158Met polymorphism (rs4680), the SNPs rs737865 and rs165599 were the targets of this study. The study was performed with 96 patients (66 male and 30 female) and 100 controls (47 male and 53 female) from Malatya region on eastern part of Turkey by using TaqMan genotyping assays. Results: We couldn’t find a significant difference between the schizophrenia patients and normal controls for any of the SNPs that were studied. The genotype frequencies in both the patient and control groups satisfied the Hardy- Weinberg equilibrium. No significant gender differences were observed for the SNPs that were investigated. No significant difference was observed in the allele or genotype frequencies as well. Conclusion: COMT gene doesn’t appear to be a risk factor in this population of schizophrenia patients in Turkey.

Genotype status of the dopamine-related catechol-O-methyltransferase (COMT) gene corresponds with desirability of “unhealthy” foods

The role of dopamine is extensively documented in weight regulation and food intake in both animal models and humans. Yet the role of dopamine has not been well studied in individual differences for food desirability. Genotype status of the dopamine-related catechol-O-methyltransferase (COMT) gene has been shown to influence dopamine levels, with greater COMT enzymatic activity in val/val individuals corresponding to greater degradation of dopamine. Decreased dopamine has been associated with poorer cognitive control and diminished goal-directed behavior in various behavioral paradigms. Additionally, dopaminergic-rich regions such as the frontal cortex and dorsal striatum have been shown to be important for supporting food-related decision-making. However, the role of dopamine, as assessed by COMT genotype status, in food desirability has not been fully explored. Therefore, we utilized an individual's COMT genotype status (n = 61) and investigated food desirability based on self-rated “healthy” and “unhealthy” food perceptions. Here we found val/val individuals (n = 19) have greater desirability for self-rated “unhealthy” food items, but not self-rated “healthy” food items, as compared to val/met (n = 24) and met/met (n = 18) individuals (p < 0.005). Utilizing an objective health measure for the food items, we also found val/val and val/met individuals have greater desirability for objectively defined “unhealthy” food items, as compared to met/met individuals (p < 0.01). This work further substantiates the role of dopamine in food-related behaviors and more specifically in relationship to food desirability for “unhealthy” food items.

Abstract 3406: Activity of catechol-O-methyltransferase gene promoter polymorphisms in renal cancer cells

Abstract Catechol-compounds such as 4-hydroxy-estrogen have been shown to play a role in the renal carcinogenesis process. To counter the effects of the highly reactive and mutagenic catechol-estrogens, the catechol-O-methyltransferase (COMT) gene detoxifies these compounds by forming methoxy compounds, which have been shown to be biologically inactive. Proper COMT function is thus vital for cells and a mechanism by which activity levels can be affected is through polymorphisms. The Val(158)Met polymorphism that correlates with renal cancer has been shown to reduce COMT enzymatic activity, but also of importance are those variants in the promoter region which can lead to alterations in gene expression levels. The aim of this study was to determine if polymorphisms of the COMT promoter can influence their transcription levels. To examine this, plasmids containing wildtype regions of the COMT promoter were obtained and site-directed mutagenesis used to create polymorphic variants. Constructs were then transfected into the Caki-1 renal cell line to measure their effects on gene expression by using a luciferase reporter assay. A total of 8 polymorphic sites covering the distal and proximal promoter region were evaluated. Results indicate that the variant at polymorphic sites rs2020917 (C to T), rs13306278 (C to T), and rs6269 (A to G) caused a significant reduction (P&amp;lt;0.01) whereas rs165656 (G to C) and rs165722 (C to T) caused a significant increase (P&amp;lt;0.01) in luciferase activity. No differences were observed for rs737865 (A to G), 4646312 (T to C), and rs3810595 (G to C). These results demonstrate polymorphisms of the COMT promoter region to cause altered expression levels in renal cells and warrant further studies with clinical case-control specimens to determine their associations for renal cell cancer. Citation Format: Inik Chang, Shinichiro Fukuhara, Darryn K. Wong, Ankurpreet Gill, Varahram Shahryari, Soichiro Yamamura, Shahana Majid, Sharanjot Saini, Hiroshi Hirata, Koji Ueno, Guoren Deng, Rajvir Dahiya, Yuichiro Tanaka. Activity of catechol-O-methyltransferase gene promoter polymorphisms in renal cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3406. doi:10.1158/1538-7445.AM2014-3406