Ivan V. Pozhidaev

Identification of 5-hydroxytryptamine receptor gene polymorphisms modulating hyperprolactinaemia in antipsychotic drug-treated patients with schizophrenia

Abstract Objectives: Hyperprolactinaemia (HPRL) is a classical side effect of antipsychotic drugs primarily attributed to blockade of dopamine D2 subtype receptors in the pituitary gland. Although dopamine is considered the primary factor inhibiting prolactin release, the activity of prolactin-producing lactotrophs is also regulated by the secretagogues thyrotrophin releasing hormone, vasoactive intestinal polypeptide and serotonin (5-hydroxytryptamine; 5-HT). Methods: We describe the association between HPRL and a set of 29 SNPs from 5-HT receptor genes HTR1A, HTR1B, HTR2A, HTR2C, HTR3A, HTR3B and HTR6 in a population of 446 Caucasians (221 males/225 females) with a clinical diagnosis of schizophrenia (according to ICD-10: F20) who were treated with classical and/or atypical antipsychotic drugs. Results: None of the studied autosomal markers were found to be associated with HPRL. However, a significant association was established between various HTR2C polymorphisms and HPRL. Conclusions: This study revealed an association between HPRL and X-chromosome haplotypes comprised of the rs569959 and rs17326429 polymorphisms.

Prolactin gene polymorphism (− 1149 G/T) is associated with hyperprolactinemia in patients with schizophrenia treated with antipsychotics

BACKGROUND Antipsychotic drugs can cause hyperprolactinemia. However, hyperprolactinemia was also observed in treatment-naive patients with a first schizophrenic episode. This phenomenon might be related to the role of prolactin as a cytokine in autoimmune diseases. Extrapituitary prolactin production is regulated by an alternative promoter, which contains the functional single nucleotide polymorphism -1149 G/T (rs1341239). We examined whether this polymorphism was associated with hyperprolactinemia in patients with schizophrenia. METHOD We recruited 443 patients with schizophrenia and 126 healthy controls. The functional polymorphism -1149 G/T (rs1341239) in the prolactin gene was genotyped with multiplexed primer extension, combined with MALDI-TOF mass spectrometry. Genotype and allele frequencies were compared between groups with the χ2 test and logistic regression models adjusting for covariates. RESULTS The frequency of genotypes and alleles in patients with schizophrenia did not differ from those in control subjects. A comparison between patients with schizophrenia with and without hyperprolactinemia revealed significantly higher frequency of the G allele in patients with hyperprolactinemia than in patients without it (χ2=7.25; p=0.007; OR=1.44 [1.10-1.89]). Accordingly, patients with hyperprolactinemia carried the GG genotype more frequently than patients without hyperprolactinemia (χ2=9.49; p=0.009). This association remained significant after adjusting the estimates for such covariates as sex, age, duration of the diseases and the dose of chlorpromazine equivalents. CONCLUSION This study revealed a significant association between the polymorphic variant rs1341239 and the development of hyperprolactinemia in patients with schizophrenia. The serum prolactin concentration in patients with schizophrenia treated with antipsychotics may provide an indication of the activity of the gene that regulates extrapituitary prolactin production which is believed to play a role in the immune system.

CYP1A2 and CYP2D6 Gene Polymorphisms in Schizophrenic Patients with Neuroleptic Drug-Induced Side Effects

Polymorphic variants of CYP1A2 and CYP2D6 genes of the cytochrome P450 system were studied in patients with schizophrenia with drug-induced motor disorders and hyperprolactinemia against the background of long-term neuroleptic therapy. We revealed an association of polymorphic variant C-163A CYP1A2*1F of CYP1A2 gene with tardive dyskinesia and association of polymorphic variant 1846G>A CY2D6*4 and genotype A/A of CYP2D6 gene (responsible for debrisoquin-4-hydroxylase synthesis) with limbotruncal tardive dyskinesia in patients with schizophrenia receiving neuroleptics for a long time.

Predictive genetic model for levodopa-induced dyskinesia in patients with Parkinson's disease

Predictive genetic model for levodopa-induced dyskinesia in patients with Parkinsons disease S.A. Ivanova(1), V.M. Alifirova(2), M.B. Freidin(3), I.V. Pozhidaev(4), O.Y. Fedorenko(4), N.A. Bokhan(4), I.A. Zhukova(5), N.G. Zhukova(5), B. Wilffert(6), A.J.M. Loonen(6) (1)Mental Health Research Institute, Molecular Genetics and Biochemistry Laboratory, Tomsk, Russia (2)Siberian State Medical University, Department of Neurology and Neurosurgery, Tomk, Russia (3)Tomsk National Research Medical Center of the Russian Academy of Sciences, Research Institute of Medical Genetics, Tomsk, Russia (4)Tomsk National Research Medical Center of the Russian Academy of Sciences, Mental Health Research Institute, Tomsk, Russia (5)Siberian State Medical University, Department of Neurology and Neurosurgery, Tomsk, Russia (6)University of Groningen, Groningen Research Institute of Pharmacy, Groningen, The Netherlands Parkinsons disease (PD), a common neurodegenerative disorder caused by the loss of the dopaminergic input to the basal ganglia, is commonly treated with levodopa (L-DOPA). The use of this drug, however, is severely limited by adverse effects. Levodopa-induced dyskinesia (LID) is one of these and characterized by involuntary muscle movements that occur as a consequence of chronic levodopa treatment. LID is a substantial barrier to effective symptomatic management of PD as up to 45% of L-DOPA users develop LID within 5 years [1]. Clinical heterogeneity of LID suggests a significant role of endogenous factors in determining their prevalence. Some evidences suggest a relationship between LID and specific genetic variants, such as polymorphisms in the genes controlling enzymes responsible for drug and monoamine metabolism, neurotransmitter receptors and proteins involved in oxidative stress or antioxidant function [2–4]. Objective: To investigate a contribution of polymorphic variants of neurotransmitter receptors and cytochrome genes in the development of LID in PD patients. Methods: A total of 212 PD patients who received L-DOPA therapy were studied. Dyskinesia was assessed by using the Abnormal Involuntary Movement Scale (AIMS). DNA extraction and genotyping were conducted according to standard protocols and blind to the clinical status of the subjects. Genotyping was carried out for 72 SNPs of DRD1, DRD2, DRD2/ANKK1, DRD3, DRD4, HTR2C, HTR3A, HTR3B, HTR6, HTR2A, HTR1A, HTR1B, CYP1A2*1F, CYP2D6*3, CYP2D6*4, CYP2C19*3, CYP2C19*17, CYP2C19*2, and GSTP1 genes using MassARRAY® Analyzer 4 (Agena Bioscience™) and the set SEQUENOM Consumables iPLEX Gold 384. Discriminant analysis and receiver operating curve (ROC)-analysis were carried out to build a genetic predictive model for dyskinesia. Results: Group of PD patients consists of 149 females and 83 males (age ranging from 40 to 86 years, average age 68.7 ± 7.6 years). The mean age of onset is 60.04 ± 9.46 years, average disease duration is 9.79 ± 5.57 years. Dyskinesia was reported in 57 (26.9%) patients. The best discriminant model was obtained with the following predictors: rs11721264, rs165774, rs3758653, rs4245147, rs6313, rs1364043, rs2734849, rs324035, rs6311, rs11246226 and rs4244285. These polymorphisms are localized in the following genes: DRD3 (rs11721264, rs324035), DRD4 (rs3758653, rs11246226), DRD2 (rs4245147, rs2734849), HTR2A (rs6313, rs6311), HTR1A (rs1364043). The discriminant model using this set of SNPs gives the error of classification about 13% and the AUC 0.795. Depending on the anticipated frequency of LID, positive and negative predictor values varied between 0.745–0.834 and 0.864–0.916, respectively. We hypothesized in our previous studies that the pathological basis of LID might be degeneration of indirect pathway medium spiny neurons [5]. These indirect pathway medium spiny neurons carry type 2 family dopamine receptors (DRD2, DRD3, DRD4), and HTR2A receptors. Moreover, dopamine release may be promoted by inhibiting serotonergic neurotransmission. Hence, the current findings are well in line with this hypothesis. Conclusion: The resulting panel of 11 SNPs provides a sufficiently high accuracy of LID prediction. The use of this panel in a prospective study will clarify the prospects for its application in clinical practice for predicting risk of LID in patients with PD. References [1] Rascol, O., Brooks, D.J., Korczyn, A.D., et al., 2000. Study Group: A five–year study of the incidence of dyskinesia in patients with early Parkinsons disease who were treated with ropinirole or L–DOPA. N Engl J Med 342, 1484–1491. [2] Ivanova, S.A., Fedorenko, O.Yu., Freidin, M.B., et al., 2016. Dissimilar mechanistic background of peripheral and orofacial hyperkinesia in patients with Parkinsons disease and levodopa-induced dyskinesia. Physiology and Pharmacology 19, 216–221. [3] Kaplan, N., Vituri, A., Korczyn, A.D., et al., 2014. Sequence variants in SLC6A3, DRD2, and BDNF genes and time to levodopa-induced dyskinesias in Parkinsons disease. J Mol Neurosci 53 (2), 183–188. [4] Loonen, A.J.M., Ivanova, S.A., 2016. Role of 5-HT2C receptors in dyskinesia. International Journal of Pharmacy and Pharmaceutical Sciences 8 (1), 5–10. [5] Loonen, A.J., Ivanova, S.A., 2013. New insights into the mechanism of drug-induced dyskinesia. CNS Spectr 18, 15–20. Keywords: Genetics / Molecular genetics Parkinsons disease levodopa-induced dyskinesia

Dopamine receptors genes polymorphisms in Parkinson patients with levodopa-induced dyskinesia

Dopamine receptors genes polymorphisms in Parkinson patients with levodopa-induced dyskinesia I. Pozhidaev(1), V.M. Alifirova(2), M.B. Freidin(3), I.A. Zhukova(2), O.Y. Fedorenko(1), D.Z. Osmanova(1), Y.S. Mironova(2), B. Wilffert(4), S.A. Ivanova(1), A.J.M. Loonen(5) (1)Mental Health Research Institute, Molecular Genetics and Biochemistry, Tomsk, Russia (2)Siberian State Medical University, Neurology and Neurosurgery, Tomsk, Russia (3)Research Institute for Medical Genetics, Laboratory of Population Genetics, Tomsk, Russia (4)Groningen Research Institute of Pharmacy, Pharmacotherapy and Clinical Pharmacology, Groningen, The Netherlands (5)Groningen Research Institute of Pharmacy, Pharmacotherapy in Psychiatric Patients, Groningen, The Netherlands Introduction: Long-term levodopa treatment of Parkinsons disease (PD) is frequently complicated by spontaneously occurring involuntary muscle movements called levodopa-induced dyskinesia (LID). LID are a substantial barrier to effective symptomatic management of Parkinsons disease (PD), as up to 45% of L-DOPA users develop LID within 5 years [1]. The exact pathological mechanism of this complication has not yet been elucidated. A lot of studies nowadays which approved complex genetic nature of LID. And these genes are involved not only for oxidative stress, but in drug metabolism too [2–4]. Objective: This study aimed to investigate a possible contribution of polymorphic variants of DRD1, DRD2, DRD2/ANKK1, DRD3, DRD4 genes in the development of LID in PD patients. Methods: 212 patients with Parkinsons disease on levodopa therapy were investigated. Dyskinesia was measured by using Abnormal Involuntary Movement Scale (AIMS). DNA extraction and fluorogenic 5′-exonuclease TaqMan genotyping assays were conducted according to standard protocols and blind to clinical status of the subjects. Genotyping was carried out on 28 SNPs of dopamine receptors (rs4532, rs936461, rs6275, rs1801028, rs4245147, rs134655, rs6277, rs1076560, rs2283265, rs179997, rs6279, rs1076562, rs2734842, rs2734849, rs11721264, rs167770, rs3773678, rs963468, rs7633291, rs2134655, rs9817063, rs324035, rs1800828, rs167771, rs6280, rs1587756, rs3758653, rs11246226) on the MassARRAY® Analyzer 4 (Agena Bioscience™) using the set SEQUENOM Consumables iPLEX Gold 384. SPSS software was used for statistical analysis. Statistical significance of the association testing was established using permutations. P-value <0.05 after permutations was considered statistically significant. Results: Patients in our cohort demonstrated typical PD demographics, with a mean age of onset of 60.04 ± 9.46 years, a mean disease duration of 9.79 ± 5.57 years. Dyskinesia was reported in 57 (26.9%) patients. The distribution of genotypes of studied genes corresponded to the Hardy-Weinberg equilibrium. We found that 5 polymorphisms (rs4245147, rs6275, rs2734842, rs6279, rs1076562) are significantly associated with LID. All these polymorphisms are located in DRD2 gene. In logistic regression models adjusted for the covariates, such as age, gender and duration of disease only one of the studied markers was associated with LID (rs4245147). Odds ratio for carriers of the genotype TT is 1.73 [95% CI: 1.12–2.70], which indicates the predisposing effect of this genotype on the development of dyskinesia. Polymorphisms in the dopamine receptors genes play significant role in the therapy response to L-DOPA as well as in various of its adverse effects. We hypothesized that single nucleotide polymorphisms in DR genes may result in a clinical phenotype contributing to an increased risk of LID. This appears to be especially true for rs4245147 of the DRD2 gene. Hence, this gene polymorphism is a good candidate for studying (genetic) biomarkers predicting the risk of developing this movement disorder. Conclusion: Rs4245147 polymorphism of the DRD2 gene is a putative component of a set of biomarkers predicting the vulnerability to develop dyskinesia. References [1] Rascol, O., Brooks, D.J., Korczyn, A.D., et al., 2000. Study Group: A five–year study of the incidence of dyskinesia in patients with early Parkinsons disease who were treated with ropinirole or L–DOPA. N Engl J Med 342, 1484–1491. [2] Ivanova, S.A., Fedorenko, O.Y., Freidin, M.B., et al., 2016. Dissimilar mechanistic background of peripheral and orofacial hyperkinesia in patients with Parkinsons disease and levodopa-induced dyskinesia. Physiology and Pharmacology 19, 216–221. [3] Kaplan, N., Vituri, A., Korczyn, A.D., et al., 2014. Sequence variants in SLC6A3, DRD2, and BDNF genes and time to levodopa-induced dyskinesias in Parkinsons disease. J Mol Neurosci 53 (2), 183–1880. [4] Rieck, M., Schumacher-Schuh, A.F., Altmann, V., et al., 2012. DRD2 haplotype is associated with dyskinesia induced by levodopa therapy in Parkinsons disease patients. Pharmacogenomics 13 (15), 1701–1710. Keywords: Receptors Dopamine Genetics / Molecular genetics

Association between P-glycoprotein polymorphisms and antipsychotic drug-induced hyperprolactinemia

Background: Regular therapy for schizophrenia includes maintenance antipsychotic treatment. Unfortunately, antipsychotics also have a spectrum of side effects, including metabolic, endocrine, cardiovascular, and movement disorders. One of the common side effects of these drugs is hyperprolactinemia (HPRL) [1]. This side effect is attributed to blockade of dopamine D2 receptors on the membranes of lactotroph cells within the pituitary gland. Certain antipsychotic drugs, e.g. risperidone, are more likely to induce HPRL because of relative accumulation within the adenohypophysis. The strong prolactin-elevating effect of risperidone reflects its relatively high blood/brain concentration ratio, a consequence of it being a substrate for the p-glycoprotein (P-gp, also known as ABCB1) pump [2]. Therefore, P-gp genotypes with altered functional activity might influence the potential of risperidone to cause HPRL as the changed blood/brain concentration ratio would lead to an altered vulnerability for CNS side effects like parkinsonism. Such side effects are expected to make dose adaptations necessary, which would also decrease exposure of lactrotroph dopamine D2 receptors. Aims: The present study aimed to investigate the influence of polymorphisms of the P-glycoprotein gene (ABCB1 gene) on the prevalence of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. Methods: We studied the association between polymorphisms of the P-gp gene (ABCB1 gene) and antipsychotic drug-induced hyperprolactinemia in patients with schizophrenia from Siberia. Evaluation of serum prolactin was performed by ELISA using reagents set PRL Test System (USA). Genotyping was carried out on 8 polymorphic variants of the P-glycoprotein gene (rs1045642, rs2032582, rs4148739, rs28401781, rs2235040, rs9282564, rs2235015, and rs2032583). Associations between HPRL and polymorphisms of P-gp gene were established using logistic regression accounting for covariates (age, sex, duration of the disease, and CPZeq). An additive genetic model was tested and the analysis was carried out both in the total sample and in subgroups stratified by the use of risperidone/paliperidone (N = 76) or sulpiride/amisulpride (N = 13). Bonferroni correction was applied assuming 5 independent tests estimated via the correlation between the SNPs. Results: 446 Russian patients with schizophrenia were examined, including 225 women and 221 men [3]. The average age of patients was 42.1 ± 1.4 years. No statistically significant associations were obtained in the total sample after correction for multiple-testing. However, the rs2032582 variant appeared to be protective against HPRL in the subgroup of patients using risperidone or paliperidone (OR = 0.17, 95% CI = 0.04–0.79, adjusted p = 0.041). Discussion: Our finding supports the hypothesis that a variant of P-gp gene may influence the likelihood of inducing HPRL in patients using risperidone or paliperidone (i.e. 9-hydroxy-risperidone). This may be related to affecting the blood/brain concentration ratio of the risperidone moiety. In the total sample the association was significant but did not survive correction for multiple testing. Moreover, another variant, rs4148739, was associated to a larger extent than rs2032582. Hence, the variant may affect the affinity of the risperidone moiety specifically without having consequences for the binding and transport of other antipsychotic drugs. Conclusion: Rs2032582 of the P-gp is negatively associated with risperidone/paliperidone-induced HPRL, but not with HPRL induced by other antipsychotic drugs. References [1] Peuskens, J., Pani, L., Detraux, J., De Hert, M., 2014. The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review. CNS Drugs 28, 421–453. [2] Ejsing, T., Pedersen, A., Linnet, K., 2005. P-glycoprotein interaction with risperidone and 9-OH-risperidone studied in vitro, in knock-out mice and in drug-drug interaction experiments. Hum Psychopharmacol 20, 493–500. [3] Ivanova, S.A., Osmanova, D.Z., Freidin, M.B., Fedorenko, O.Y., Boiko, A.S., Pozhidaev, I.V., Semke, A.V., Bokhan, N.A., Agarkov, A.A., Wilffert, B., Loonen, A.J.M., 2017. Identification of 5-hydroxytryptamine receptor gene polymorphisms modulating hyperprolactinaemia in antipsychotic drug-treated patients with schizophrenia. World J Biol Psychiatry 18, 239–246. Keywords: Schizophrenia: clinical Pharmacokinetics Neuroendocrinology

Gene polymorphism of neurotransmitter transporters in schizophrenic patients with drug-induced hyperprolactinemia

The regular therapy of schizophrenia includes a maintenance antipsychotic treatment, which improves the long-term prognosis of the disease [2]. Unfortunately antipsychotics also have a spectrum of side effects, including metabolic, endocrine and movement disorders [3,4]. One of the common side effects of these drugs is hyperprolactinemia (HP) [1]. The results of pharmacogenetic studies aimed at prognostic evaluation of the safe use of antipsychotics are the most persuasive. The components of dopamine, serotonin and norepinephrine neurotransmission in schizophrenia are considered as the main target for the action of antipsychotics. The present study aims to elucidate the role of 12 SNPs of dopamine transporter gene SLC6A3, 9 SNPs of norepinephrine transporter gene SLC6A2 and polymorphism of vesicular monoamine transporter gene SLC6A2 in the pathogenesis of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. A total of 445 ethnic Russian patients from Siberia regions were studied, including 224 women and 221 men with a diagnosis of paranoid schizophrenia (the mean age - 42.1±1.4 years). Prolactin level was analyzed using the AccuBind ELISA Microwells kit (Monobind Inc., USA). Genotyping of SNPs was done with The MassARRAY® Analyzer 4 by Agena Bioscience™, using SEQUENOM. Statistical analysis was performed using the SPSS program. The Hardy-Weinberg equilibrium and differences in genotype frequencies were tested using a chi-square test. Differences were considered significant at p

Gene polymorphism of serotonin receptors and drug-induced hyperprolactinemia in schizophrenic patients

Background: Antipsychotics have been used for more than 50 years in the treatment of schizophrenia and many other psychiatric disorders. Schizophrenic patients have to take antipsychotic medication for a long time, often throughout the life [1]. Hyper prolactinemia in these patients is a common and serious side effect of therapy with atypical antipsychotics. Genes coding for serotonin receptors are considered as candidate genes responsible for the particular antipsychotic effects of neuroleptics [2]. The present study aimed to investigate the role of polymorphisms of the serotonin receptors genes (HTR1A, HTR1B, HTR2A, HTR2C, HTR3A, HTR3B, HTR6) in the pathogenesis of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. Methods: 446 Russian patients with schizophrenia were examined, including 225 women and 221 men. The average age of patients was 42.1±1.4 years. Evaluation of serum prolactin performed by ELISA using reagents set PRL Test System (USA). Genotyping was carried out on 29 polymorphic variants of the serotonin receptor genes HTR1A (rs6295, rs1364043, rs10042486, rs1800042, rs749099), HTR1B (rs6298, rs6296, rs130058), HTR2A (rs6311, rs6313, rs6314, rs7997012, rs1928040, rs9316233, rs2224721, rs6312), HTR2C (rs6318, rs5946189, rs569959, rs17326429, rs4911871, rs3813929, rs1801412, rs12858300), HTR3A (rs1062613, rs33940208, rs1176713), HTR3B (rs1176744) and HTR6 (rs1805054). The SPSS software was used for statistical analysis. The Hardy-Weinberg equilibrium (HWE) of genotypic frequencies was tested by the chi-square test. Results: We studied the association between polymorphisms of relevant 5-HT receptor genes and antipsychotic drug-induced hyperprolactinemia in patients with schizophrenia from Siberia. All patients with schizophrenia were divided into two groups: those with and without hyperprolactinemia. Statistically significant results were obtained for polymorphic variants of the genes rs6312 HTR2A (χ2 = 4.685; p = 0.030), rs12858300 HTR2C, rs569959 HTR2C, which suggests the participation of these polymorphic variants in the development of hyperprolactinemia. When men and women were studied separately, only rs569959 HTR2C (χ2 = 6.284; p = 0.043) in men reached the nominal significance threshold. This finding is probably related to the X-bound character of HTR2C (i.e., men are hemizygotes). Also, we found a statistically significant association rs12858300 HTR2C (χ2 = 9.429; p = 0.002) in the female group. We did not find statistically significant association for other polymorphisms HTR1A (rs6295, rs1364043, rs10042486, rs1800042, rs749099), HTR1B (rs6298, rs6296, rs130058), HTR2A (rs6311, rs6313, rs6314, rs7997012, rs1928040, rs9316233, rs2224721), HTR2C (rs6318, rs5946189, rs17326429, rs4911871, rs3813929, rs1801412), HTR3A (rs1062613, rs33940208, rs1176713), HTR3B (rs1176744) and HTR6 (rs1805054). Though hyperprolactinemia is primarily attributed to blockade of DRD2 in the pituitary gland, the secretion of prolactin is also modulated by 5-HT. The involvement of the HTR1A, HTR2A, HTR2C, and HTR3 in the serotonergic-induced prolactin response is well documented. Conclusion: Our results indicate that genetic variants of HTR2C may have functional consequences on the modulation of prolactin secretion. Further search for genetic markers associated with the development of side effects of neuroleptic therapy, will contribute to the development of effective methods of diagnosis, correction and treatment of disease, as well as of adherence of patients with mental disorders to psychotropic therapy.