p38 MAP Kinase Links CAR Activation and Inactivation in the Nucleus via Phosphorylation at Threonine 38.

Drug Metab Dispos. 2016 Jun;44(6):871-6

Authors: Hori T, Moore R, Negishi M

Abstract
Nuclear receptor constitutive androstane receptor (CAR, NR1I3), which regulates hepatic drug and energy metabolisms as well as cell growth and death, is sequestered in the cytoplasm as its inactive form phosphorylated at threonine 38. CAR activators elicit dephosphorylation, and nonphosphorylated CAR translocates into the nucleus to activate its target genes. CAR was previously found to require p38 mitogen-activated protein kinase (MAPK) to transactivate the cytochrome P450 2B (CYP2B) genes. Here we have demonstrated that p38 MAPK forms a complex with CAR, enables it to bind to the response sequence, phenobarbital-responsive enhancer module (PBREM), within the CYP2B promoter, and thus recruits RNA polymerase II to activate transcription. Subsequently, p38 MAPK elicited rephosphorylation of threonine 38 to inactivate CAR and exclude it from the nucleus. Thus, nuclear p38 MAPK exerted dual regulation by sequentially activating and inactivating CAR-mediated transcription through phosphorylation of threonine 38.

PMID: 27074912 [PubMed - indexed for MEDLINE]

12 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

pharmacogenomics

These pubmed results were generated on 2018/01/10

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Diverse genetic-driven immune landscapes dictate tumor progression through distinct mechanisms.

Nat Med. 2018 Jan 08;:

Authors: Bezzi M, Seitzer N, Ishikawa T, Reschke M, Chen M, Wang G, Mitchell C, Ng C, Katon J, Lunardi A, Signoretti S, Clohessy JG, Zhang J, Pandolfi PP

Abstract
Multiple immune-cell types can infiltrate tumors and promote progression and metastasis through different mechanisms, including immunosuppression. How distinct genetic alterations in tumors affect the composition of the immune landscape is currently unclear. Here, we characterized the immune-cell composition of prostate cancers driven by the loss of the critical tumor suppressor gene Pten, either alone or in combination with the loss of Trp53, Zbtb7a or Pml. We observed a striking quantitative and qualitative heterogeneity that was directly dependent on the specific genetic events in the tumor and ranged from 'cold', noninflamed tumors to massively infiltrated landscapes-results with important therapeutic implications. Further, we showed these qualitative differences in transcriptomic analysis of human prostate cancer samples. These data suggest that patient stratification on the basis of integrated genotypic-immunophenotypic analyses may be necessary for successful clinical trials and tailored precision immunological therapies.

PMID: 29309058 [PubMed - as supplied by publisher]

The influence of CYP3A5*3 and BCRPC421A genetic polymorphisms on the pharmacokinetics of felodipine in healthy Chinese volunteers.

J Clin Pharm Ther. 2017 Jun;42(3):345-349

Authors: Xiang Q, Li C, Zhao X, Cui YM

Abstract
WHAT IS KNOWN AND OBJECTIVE: The role of CYP3A5 in drug metabolism has been receiving attention because CYP3A5 may be more involved in the metabolism of CYP3A substrates in vivo than previously thought. The polymorphism of transporters, such as P-gp (P-glycoprotein) and breast cancer-related protein (BCRP), influences the metabolism of these substrates, and felodipine is a substrate of P-gp. The aim of this study was to evaluate the pharmacogenetic variability in the disposition of felodipine in healthy Chinese subjects.
METHODS: A single dose of 5 mg felodipine was orally administered to 45 healthy Chinese subjects. The serum concentration of felodipine was measured by using LC/MS/MS. We detected the SNPs of cytochromes P450 enzymes and transporters, which play vital roles in drug metabolism and have a high frequency of mutation in Chinese population.
RESULTS AND DISCUSSION: The area under the plasma concentration-time curve (AUC) within the time points 0 to 72 h (AUC(0-72) ) after felodipine administration was significantly higher in subjects possessing the BCRP421AA alleles than in those with the BCRP421 CC or CA genotype (P = 0·034). The subjects with CYP3A5*3/*3 (n = 27) had higher felodipine exposure than CYP3A5*1/*3 (n = 15) (P = 0·035).
WHAT IS NEW AND CONCLUSION: This study showed that the genetic polymorphisms of CYP3A5*3 and BCRPC421A might explain the variability in the pharmacokinetics of felodipine in the Chinese population.

PMID: 28244604 [PubMed - indexed for MEDLINE]

COMT Val158Met polymorphism moderates the association between PTSD symptom severity and hippocampal volume.

J Psychiatry Neurosci. 2017 Mar;42(2):95-102

Authors: Hayes JP, Logue MW, Reagan A, Salat D, Wolf EJ, Sadeh N, Spielberg JM, Sperbeck E, Hayes SM, McGlinchey RE, Milberg WP, Verfaellie M, Stone A, Schichman SA, Miller MW

Abstract
BACKGROUND: Memory-based alterations are among the hallmark symptoms of posttraumatic stress disorder (PTSD) and may be associated with the integrity of the hippocampus. However, neuroimaging studies of hippocampal volume in individuals with PTSD have yielded inconsistent results, raising the possibility that various moderators, such as genetic factors, may influence this association. We examined whether the catechol-O-methyltransferase (COMT) Val158Met polymorphism, which has previously been shown to be associated with hippocampal volume in healthy individuals, moderates the association between PTSD and hippocampal volume.
METHODS: Recent war veterans underwent structural MRI on a 3 T scanner. We extracted volumes of the right and left hippocampus using FreeSurfer and adjusted them for individual differences in intracranial volume. We assessed PTSD severity using the Clinician-Administered PTSD Scale. Hierarchical linear regression was used to model the genotype (Val158Met polymorphism) × PTSD severity interaction and its association with hippocampal volume.
RESULTS: We included 146 white, non-Hispanic recent war veterans (90% male, 53% with diagnosed PTSD) in our analyses. A significant genotype × PTSD symptom severity interaction emerged such that individuals with greater current PTSD symptom severity who were homozygous for the Val allele showed significant reductions in left hippocampal volume.
LIMITATIONS: The direction of proposed effects is unknown, thus precluding definitive assessment of whether differences in hippocampal volume reflect a consequence of PTSD, a pre-existing characteristic, or both.
CONCLUSION: Our findings suggest that the COMT polymorphism moderates the association between PTSD and hippocampal volume. These results highlight the role that the dopaminergic system has in brain structure and suggest a possible mechanism for memory disturbance in individuals with PTSD.

PMID: 28234210 [PubMed - indexed for MEDLINE]

How can we optimise inhaled beta2 agonist dose as 'reliever' medicine for wheezy pre-school children? Study protocol for a randomised controlled trial.

Trials. 2016 Nov 11;17(1):541

Authors: Mukhopadhyay S, Seddon P, Earl G, Wileman E, Symes L, Olden C, Alberti C, Bremner S, Lansley A, Palmer CN, Beydon N

Abstract
BACKGROUND: Asthma is a common problem in children and, if inadequately controlled, may seriously diminish their quality of life. Inhaled short-acting beta2 agonists such as salbutamol are usually prescribed as 'reliever' medication to help control day-to-day symptoms such as wheeze. As with many medications currently prescribed for younger children (defined as those aged 2 years 6 months to 6 years 11 months), there has been no pre-licensing age-specific pharmacological testing; consequently, the doses currently prescribed (200-1000 μg) may be ineffective or likely to induce unnecessary side effects. We plan to use the interrupter technique to measure airway resistance in this age group, allowing us for the first time to correlate inhaled salbutamol dose with changes in clinical response. We will measure urinary salbutamol levels 30 min after dosing as an estimate of salbutamol doses in the lungs, and also look for genetic polymorphisms linked to poor responses to inhaled salbutamol.
METHODS: This is a phase IV, randomised, controlled, observer-blinded, single-centre trial with four parallel groups (based on a sparse sampling approach) and a primary endpoint of the immediate bronchodilator response to salbutamol so that we can determine the most appropriate dose for an individual younger child. Simple randomisation will be used with a 1:1:1:1 allocation.
DISCUSSION: The proposed research will exploit simple, non-invasive and inexpensive tests that can mostly be performed in an outpatient setting in order to help develop the evidence for the correct dose of salbutamol in younger children with recurrent wheeze who have been prescribed salbutamol by their doctor.
TRIAL REGISTRATION: EudraCT2014-001978-33, ISRCTN15513131. Registered on 8 April 2015.

PMID: 27836009 [PubMed - indexed for MEDLINE]

TPH-2 Polymorphisms Interact with Early Life Stress to Influence Response to Treatment with Antidepressant Drugs.

Int J Neuropsychopharmacol. 2016 Nov;19(11):

Authors: Xu Z, Reynolds GP, Yuan Y, Shi Y, Pu M, Zhang Z

Abstract
BACKGROUND: Variation in genes implicated in monoamine neurotransmission may interact with environmental factors to influence antidepressant response. We aimed to determine how a range of single nucleotide polymorphisms in monoaminergic genes influence this response to treatment and how they interact with childhood trauma and recent life stress in a Chinese sample. An initial study of monoaminergic coding region single nucleotide polymorphisms identified significant associations of TPH2 and HTR1B single nucleotide polymorphisms with treatment response that showed interactions with childhood and recent life stress, respectively (Xu et al., 2012).
METHODS: A total of 47 further single nucleotide polymorphisms in 17 candidate monoaminergic genes were genotyped in 281 Chinese Han patients with major depressive disorder. Response to 6 weeks' antidepressant treatment was determined by change in the 17-item Hamilton Depression Rating Scale score, and previous stressful events were evaluated by the Life Events Scale and Childhood Trauma Questionnaire-Short Form.
RESULTS: Three TPH2 single nucleotide polymorphisms (rs11178998, rs7963717, and rs2171363) were significantly associated with antidepressant response in this Chinese sample, as was a haplotype in TPH2 (rs2171363 and rs1487278). One of these, rs2171363, showed a significant interaction with childhood adversity in its association with antidepressant response.
CONCLUSIONS: These findings provide further evidence that variation in TPH2 is associated with antidepressant response and may also interact with childhood trauma to influence outcome of antidepressant treatment.

PMID: 27521242 [PubMed - indexed for MEDLINE]

Optimization of Clonazepam Therapy Adjusted to Patient's CYP3A Status and NAT2 Genotype.

Int J Neuropsychopharmacol. 2016 Dec;19(12):

Authors: Tóth K, Csukly G, Sirok D, Belic A, Kiss Á, Háfra E, Déri M, Menus Á, Bitter I, Monostory K

Abstract
BACKGROUND: The shortcomings of clonazepam therapy include tolerance, withdrawal symptoms, and adverse effects such as drowsiness, dizziness, and confusion leading to increased risk of falls. Inter-individual variability in the incidence of adverse events in patients partly originates from the differences in clonazepam metabolism due to genetic and nongenetic factors.
METHODS: Since the prominent role in clonazepam nitro-reduction and acetylation of 7-amino-clonazepam is assigned to CYP3A and N-acetyl transferase 2 enzymes, respectively, the association between the patients' CYP3A status (CYP3A5 genotype, CYP3A4 expression) or N-acetyl transferase 2 acetylator phenotype and clonazepam metabolism (plasma concentrations of clonazepam and 7-amino-clonazepam) was evaluated in 98 psychiatric patients suffering from schizophrenia or bipolar disorders.
RESULTS: The patients' CYP3A4 expression was found to be the major determinant of clonazepam plasma concentrations normalized by the dose and bodyweight (1263.5±482.9 and 558.5±202.4ng/mL per mg/kg bodyweight in low and normal expressers, respectively, P<.0001). Consequently, the dose requirement for the therapeutic concentration of clonazepam was substantially lower in low-CYP3A4 expresser patients than in normal expressers (0.029±0.011 vs 0.058±0.024mg/kg bodyweight, P<.0001). Furthermore, significantly higher (about 2-fold) plasma concentration ratio of 7-amino-clonazepam and clonazepam was observed in the patients displaying normal CYP3A4 expression and slower N-acetylation than all the others.
CONCLUSION: Prospective assaying of CYP3A4 expression and N-acetyl transferase 2 acetylator phenotype can better identify the patients with higher risk of adverse reactions and can facilitate the improvement of personalized clonazepam therapy and withdrawal regimen.

PMID: 27639091 [PubMed - indexed for MEDLINE]

Neonatal adverse drug reactions: an analysis of reports to the French pharmacovigilance database.

Br J Clin Pharmacol. 2016 Oct;82(4):1058-68

Authors: Kaguelidou F, Beau-Salinas F, Jonville-Bera AP, Jacqz-Aigrain E

Abstract
AIM: Term and preterm neonates are at high risk for serious adverse drug reactions (ADRs).
METHODS: A descriptive study of reports registered in the French pharmacovigilance database from 1986 to 2012 were obtained. All reports concerning neonates (≤1 month of life) with direct drug exposure were retrieved. Characteristics of the reports, including reported ADR(s), drug(s) and the causality assessment using the French causality assessment method, were described.
RESULTS: A total of 1688 reports were analyzed and more than half of them were classified as serious (n = 995). Median age at ADR occurrence was 9 days. Overall, 3127 ADRs were described in these reports in relation to 2238 suspect/interacting drugs. The most commonly reported system organ classes (SOCs) were injury, poisoning and procedural complications (16%), general disorders and administration site conditions (12.5%) and blood and lymphatic system disorders (12%). In the majority of ADRs reported (73%), infants fully recovered and less than 4% of neonates deceased as a consequence of the reported ADR. One out of five ADRs was associated with drug administration errors. Therapeutic classes commonly incriminated were anti-infectives, nervous system and alimentary tract drugs. Substances most frequently related to serious ADRs were zidovudine, ibuprofen and nevirapine. Among the 10 most frequently encountered drug-ADR pairs, two substances were mainly implicated, zidovudine in haematological adverse reactions and phytomenadione in maladministrations.
CONCLUSIONS: Anti-infective drugs, mainly antiretroviral therapy, account for the majority of ADRs reported in neonates. The specific issue of drug maladministration and medication errors remains to be addressed in neonates.

PMID: 27276109 [PubMed - indexed for MEDLINE]

Catechol-O-Methyltransferase Val158Met Polymorphism and Clinical Response to Antipsychotic Treatment in Schizophrenia and Schizo-Affective Disorder Patients: a Meta-Analysis.

Int J Neuropsychopharmacol. 2016 May;19(5):

Authors: Huang E, Zai CC, Lisoway A, Maciukiewicz M, Felsky D, Tiwari AK, Bishop JR, Ikeda M, Molero P, Ortuno F, Porcelli S, Samochowiec J, Mierzejewski P, Gao S, Crespo-Facorro B, Pelayo-Terán JM, Kaur H, Kukreti R, Meltzer HY, Lieberman JA, Potkin SG, Müller DJ, Kennedy JL

Abstract
BACKGROUND: The catechol-O-methyltransferase (COMT) enzyme plays a crucial role in dopamine degradation, and the COMT Val158Met polymorphism (rs4680) is associated with significant differences in enzymatic activity and consequently dopamine concentrations in the prefrontal cortex. Multiple studies have analyzed the COMT Val158Met variant in relation to antipsychotic response. Here, we conducted a meta-analysis examining the relationship between COMT Val158Met and antipsychotic response.
METHODS: Searches using PubMed, Web of Science, and PsycInfo databases (03/01/2015) yielded 23 studies investigating COMT Val158Met variation and antipsychotic response in schizophrenia and schizo-affective disorder. Responders/nonresponders were defined using each study's original criteria. If no binary response definition was used, authors were asked to define response according to at least 30% Positive and Negative Syndrome Scale score reduction (or equivalent in other scales). Analysis was conducted under a fixed-effects model.
RESULTS: Ten studies met inclusion criteria for the meta-analysis. Five additional antipsychotic-treated samples were analyzed for Val158Met and response and included in the meta-analysis (ntotal=1416). Met/Met individuals were significantly more likely to respond than Val-carriers (P=.039, ORMet/Met=1.37, 95% CI: 1.02-1.85). Met/Met patients also experienced significantly greater improvement in positive symptoms relative to Val-carriers (P=.030, SMD=0.24, 95% CI: 0.024-0.46). Posthoc analyses on patients treated with atypical antipsychotics (n=1207) showed that Met/Met patients were significantly more likely to respond relative to Val-carriers (P=.0098, ORMet/Met=1.54, 95% CI: 1.11-2.14), while no difference was observed for typical-antipsychotic-treated patients (n=155) (P=.65).
CONCLUSIONS: Our findings suggest that the COMT Val158Met polymorphism is associated with response to antipsychotics in schizophrenia and schizo-affective disorder patients. This effect may be more pronounced for atypical antipsychotics.

PMID: 26745992 [PubMed - indexed for MEDLINE]

HTR1A Polymorphisms and Clinical Efficacy of Antipsychotic Drug Treatment in Schizophrenia: A Meta-Analysis.

Int J Neuropsychopharmacol. 2016 May;19(5):

Authors: Takekita Y, Fabbri C, Kato M, Koshikawa Y, Tajika A, Kinoshita T, Serretti A

Abstract
BACKGROUND: This meta-analysis was conducted to evaluate whether HTR1A gene polymorphisms impact the efficacy of antipsychotic drugs in patients with schizophrenia.
METHODS: Candidate gene studies that were published in English up to August 6, 2015 were identified by a literature search of PubMed, Web of Science, and Google scholar. Data were pooled from individual clinical trials considering overall symptoms, positive symptoms and negative symptoms, and standard mean differences were calculated by applying a random-effects model.
RESULTS: The present meta-analysis included a total of 1281 patients from 10 studies. Three polymorphisms of HTR1A (rs6295, rs878567, and rs1423691) were selected for the analysis. In the pooled data from all studies, none of these HTR1A polymorphisms correlated significantly with either overall symptoms or positive symptoms. However, C allele carriers of the rs6295 polymorphism showed a significantly greater negative symptoms improvement than G allele carriers (P=.04, standardized mean difference =-0.14, 95％CI = 0.01 to 0.28).
CONCLUSIONS: The results of our present analysis indicate that the HTR1A rs6295 polymorphism may impact negative symptoms improvement but not on either overall symptoms or positive symptoms improvement. However, this meta-analysis was based on a small number of studies and patients, and the effect size on negative symptoms was small. Given this limitation, the results should be confirmed by further investigations.

PMID: 26568455 [PubMed - indexed for MEDLINE]

The role of tryptophan metabolism in postpartum depression.

Metab Brain Dis. 2018 Jan 06;:

Authors: Duan KM, Ma JH, Wang SY, Huang Z, Zhou Y, Yu H

Abstract
The Postpartum depression (PPD) is the most common postpartum psychiatric disorder, afflicting approximately 10%-20% of new mothers. Clinical symptoms of the PPD include depressive disorder, agitation, insomnia, anxiety and confusion, resulting in an increase in suicidal tendencies, thereby having significant impacts on the puerpera, newborn and their family. A growing body of data indicate a role for alterations in tryptophan metabolism in the PPD. The metabolism of tryptophan produces an array of crucial factors that can differentially regulate key physiological processes linked to the PPD. Importantly, an increase in stress hormones and immune-inflammatory activity drives tryptophan to the production of neuroregulatory kynurenine pathway products and away from the serotonin and melatonin pathways. This links the PPD to other disorders of depressed mood, which are classically associated with decreased serotonin and melatonin, coupled to increases in kynurenine pathway products. Several kynurenine pathway products, such as kynurenic acid and quinolinic acid, can have neuroregulatory effects, with consequences pathological underpinnings of the PPD. The current article reviews the role of alterations in tryptophan metabolism in the PPD.

PMID: 29307018 [PubMed - as supplied by publisher]

Genetics and Treatment Response in Parkinson's Disease: An Update on Pharmacogenetic Studies.

Neuromolecular Med. 2018 Jan 05;:

Authors: Politi C, Ciccacci C, Novelli G, Borgiani P

Abstract
Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by a progressive loss of dopamine neurons of the central nervous system. The disease determines a significant disability due to a combination of motor symptoms such as bradykinesia, rigidity and rest tremor and non-motor symptoms such as sleep disorders, hallucinations, psychosis and compulsive behaviors. The current therapies consist in combination of drugs acting to control only the symptoms of the illness by the replacement of the dopamine lost. Although patients generally receive benefits from this symptomatic pharmacological management, they also show great variability in drug response in terms of both efficacy and adverse effects. Pharmacogenetic studies highlighted that genetic factors play a relevant influence in this drug response variability. In this review, we tried to give an overview of the recent progresses in the pharmacogenetics of PD, reporting the major genetic factors identified as involved in the response to drugs and highlighting the potential use of some of these genomic variants in the clinical practice. Many genes have been investigated and several associations have been reported especially with adverse drug reactions. However, only polymorphisms in few genes, including DRD2, COMT and SLC6A3, have been confirmed as associated in different populations and in large cohorts. The identification of genomic biomarkers involved in drug response variability represents an important step in PD treatment, opening the prospective of more personalized therapies in order to identify, for each person, the better therapy in terms of efficacy and toxicity and to improve the PD patients' quality of life.

PMID: 29305687 [PubMed - as supplied by publisher]

Astrocyte-specific transcriptome responses to chronic ethanol consumption.

Pharmacogenomics J. 2018 Jan 05;:

Authors: Erickson EK, Farris SP, Blednov YA, Mayfield RD, Harris RA

Abstract
Astrocytes play critical roles in central nervous system (CNS) homeostasis and are implicated in the pathogenesis of neurological and psychiatric conditions, including drug dependence. Little is known about the effects of chronic ethanol consumption on astrocyte gene expression. To address this gap in knowledge, we performed transcriptome-wide RNA sequencing of astrocytes isolated from the prefrontal cortex (PFC) of mice following chronic ethanol consumption. Differential expression analysis revealed ethanol-induced changes unique to astrocytes that were not identified in total homogenate preparations. Astrocyte-specific gene expression revealed calcium-related signaling and regulation of extracellular matrix genes as responses to chronic ethanol use. These findings emphasize the importance of investigating expression changes in specific cellular populations to define molecular consequences of chronic ethanol consumption in mammalian brain.

PMID: 29305589 [PubMed - as supplied by publisher]

18 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

pharmacogenomics

These pubmed results were generated on 2018/01/06

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

18 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

pharmacogenomics

These pubmed results were generated on 2018/01/06

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Link synthetic lethality to drug sensitivity of cancer cells.

Brief Bioinform. 2017 Dec 28;:

Authors: Wang R, Han Y, Zhao Z, Yang F, Chen T, Zhou W, Wang X, Qi L, Zhao W, Guo Z, Gu Y

Abstract
Synthetic lethal (SL) interactions occur when alterations in two genes lead to cell death but alteration in only one of them is not lethal. SL interactions provide a new strategy for molecular-targeted cancer therapy. Currently, there are few drugs targeting SL interactions that entered into clinical trials. Therefore, it is necessary to investigate the link between SL interactions and drug sensitivity of cancer cells systematically for drug development purpose. We identified SL interactions by integrating the high-throughput data from The Cancer Genome Atlas, small hairpin RNA data and genetic interactions of yeast. By integrating SL interactions from other studies, we tested whether the SL pairs that consist of drug target genes and the genes with genomic alterations are related with drug sensitivity of cancer cells. We found that only 6.26%∼34.61% of SL interactions showed the expected significant drug sensitivity using the pooled cancer cell line data from different tissues, but the proportion increased significantly to approximately 90% using the cancer cell line data for each specific tissue. From an independent pharmacogenomics data of 41 breast cancer cell lines, we found three SL interactions (ABL1-IFI16, ABL1-SLC50A1 and ABL1-SYT11) showed significantly better prognosis for the patients with both genes being altered than the patients with only one gene being altered, which partially supports the SL effect between the gene pairs. Our study not only provides a new way for unraveling the complex mechanisms of drug sensitivity but also suggests numerous potentially important drug targets for cancer therapy.

PMID: 29300844 [PubMed - as supplied by publisher]

The phosphatidylinositide 3-kinase (PI3K) signaling pathway is a determinant of zileuton response in adults with asthma.

Pharmacogenomics J. 2018 Jan 03;:

Authors: Dahlin A, Qiu W, Litonjua AA, Lima JJ, Tamari M, Kubo M, Irvin CG, Peters SP, Wu AC, Weiss ST, Tantisira KG

Abstract
Variable responsiveness to zileuton, a leukotriene antagonist used to treat asthma, may be due in part to genetic variation. While individual SNPs were previously associated with zileuton-related lung function changes, specific quantitative trait loci (QTLs) and biological pathways that may contribute have not been identified. In this study, we investigated the hypothesis that genetic variation within biological pathways is associated with zileuton response. We performed an integrative QTL mapping and pathway enrichment study to investigate data from a GWAS of zileuton response, in addition to mRNA expression profiles and leukotriene production data from lymphoblastoid cell lines (LCLs) (derived from asthmatics) that were treated with zileuton or ethanol (control). We identified 1060 QTLs jointly associated with zileuton-related differential LTB4 production in LCLs and lung function change in patients taking zileuton, of which eight QTLs were also significantly associated with persistent LTB4 production in LCLs following zileuton treatment (i.e., 'poor' responders). Four nominally significant trans-eQTLs were predicted to regulate three candidate genes (SELL, MTF2, and GAL), the expression of which was significantly reduced in LCLs following zileuton treatment. Gene and pathway enrichment analyses of QTL associations identified multiple genes and pathways, predominantly related to phosphatidyl inositol signaling via PI3K. We validated the PI3K pathway activation status in a subset of LCLs demonstrating variable zileuton-related LTB4 production, and show that in contrast to LCLs that responded to zileuton, the PI3K pathway was activated in poor responder LCLs. Collectively, these findings demonstrate a role for the PIK3 pathway and its targets as important determinants of differential responsiveness to zileuton.

PMID: 29298996 [PubMed - as supplied by publisher]

Nuclear receptor gene polymorphisms and warfarin dose requirements in the Quebec Warfarin Cohort.

Pharmacogenomics J. 2018 Jan 03;:

Authors: Shahabi P, Lamothe F, Dumas S, Rouleau-Mailloux É, Feroz Zada Y, Provost S, Asselin G, Mongrain I, Valois D, Gaulin Marion MJ, Lemieux Perreault LP, Perreault S, Dubé MP

Abstract
Warfarin is primarily metabolized by cytochrome 2C9, encoded by gene CYP2C9. Here, we investigated whether variants in nuclear receptor genes which regulate the expression of CYP2C9 are associated with warfarin response. We used data from 906 warfarin users from the Quebec Warfarin Cohort (QWC) and tested the association of warfarin dose requirement at 3 months following the initiation of therapy in nine nuclear receptor genes: NR1I3, NR1I2, NR3C1, ESR1, GATA4, RXRA, VDR, CEBPA, and HNF4A. Three correlated SNPs in the VDR gene (rs4760658, rs11168292, and rs11168293) were associated with dose requirements of warfarin (P = 2.68 × 10-5, P = 5.81 × 10-4, and P = 5.94 × 10-4, respectively). Required doses of warfarin were the highest for homozygotes of the minor allele at the VDR variants (P < 0.0026). Variants in the VDR gene were associated with the variability in response to warfarin, emphasizing the possible clinical relevance of nuclear receptor gene variants on the inter-individual variability in drug metabolism.

PMID: 29298995 [PubMed - as supplied by publisher]

Cost-effectiveness of HLA-DQB1/HLA-B pharmacogenetic-guided treatment and blood monitoring in US patients taking clozapine.

Pharmacogenomics J. 2018 Jan 03;:

Authors: Girardin FR, Poncet A, Perrier A, Vernaz N, Pletscher M, F Samer C, Lieberman JA, Villard J

Abstract
Less than 1% of adult patients with schizophrenia taking clozapine develop agranulocytosis, and most of these cases occur within the first weeks of treatment. The human leukocyte antigen (HLA) region has been associated with genetic susceptibility to clozapine-induced agranulocytosis (single amino acid changes in HLA-DQB1 (126Q) and HLA-B (158T)). The current study aimed to evaluate the cost-effectiveness, from a healthcare provider's perspective, of an HLA genotype-guided approach in patients with treatment-resistant schizophrenia who were taking clozapine and to compare the results with the current absolute neutrophil count monitoring (ANCM) schemes used in the USA. A semi-Markovian model was developed to simulate the progress of a cohort of adult men and women who received clozapine as a third-line antipsychotic medication. We compared current practices using two genotype-guided strategies: (1) HLA genotyping followed by clozapine, with ANCM only for patients who tested positive for one or both alleles (genotype-guided blood sampling); (2) HLA genotyping followed by clozapine for low-risk patients and alternative antipsychotics for patients who tested positive (clozapine substitution scheme). Up to a decision threshold of $3.9 million per quality-adjusted life-year (90-fold the US gross domestic product per capita), the base-case results indicate that compared with current ANCM, genotype-guided blood sampling prior to clozapine initiation appeared cost-effective for targeted blood monitoring only in patients with HLA susceptibility alleles. Sensitivity analysis demonstrated that at a cost of genotype testing of up to USD700, HLA genotype-guided blood monitoring remained a cost-effective strategy compared with either current ANCM or clozapine substitution.

PMID: 29298994 [PubMed - as supplied by publisher]