Janet Hoenicka

The new mutation, E46K, of alpha-synuclein causes Parkinson and Lewy body dementia.

Familial parkinsonism and dementia with cortical and subcortical Lewy bodies is uncommon, and no genetic defect has been reported in the previously described sibships. We present a Spanish family with autosomal dominant parkinsonism, dementia, and visual hallucinations of variable severity. The postmortem examination showed atrophy of the substantia nigra, lack of Alzheimer pathology, and numerous Lewy bodies which were immunoreactive to α‐synuclein and ubiquitin in cortical and subcortical areas. Sequencing of the α‐synuclein gene showed a novel, nonconservative E46K mutation in heterozygosis. The E46K mutation was present in all affected family members and in three young asymptomatic subjects, but it was absent in healthy and pathological controls. The novel mutation, that substitutes a dicarboxylic amino acid, glutamic acid, with a basic amino acid such as lysine in a much conserved area of the protein, is likely to produce severe disturbance of protein function. Our data show that, in addition to the previously described hereditary α‐synucleinopathies, dementia with Lewy bodies is related to mutation of α‐synuclein.

Steele-Richardson-Olszewski syndrome in a patient with a single C212Y mutation in the parkin protein.

Steele‐Richardson‐Olszewski syndrome (SROS) is a neurodegenerative disorder of unknown aetiology, most frequently sporadic. Familial cases of SROS have been described. An intronic polymorphism of the tau gene is associated with sporadic SROS and mutations of the tau gene are present in atypical cases of SROS. The role of tau has been excluded in other families with pathology proven SROS, suggesting that this syndrome may have multiple causes. An 82‐year‐old patient, father of 3 children with autosomal recessive juvenile parkinsonism due to combined heterozygous mutations of the parkin gene, developed clinical features of SROS 2 years before death. The diagnosis was confirmed by pathology. He carried the C212Y mutation of the parkin gene and was homozygous for the A0 polymorphism and for the H1 haplotype. The role of parkin in the processing of tau is discussed.

The anti-inflammatory prostaglandin 15d-PGJ2 and its nuclear receptor PPARgamma are decreased in schizophrenia

A number of findings suggest that inflammation plays a role in the pathophysiology of schizophrenia. Taking into account a physiological balance between pro- and anti-inflammatory mediators, we measured the plasma levels of cyclooxygenase-derived mediators and other key pro- and anti-inflammatory transcription factors in peripheral blood mononuclear cells (PBMC). Forty healthy subjects and 46 treated chronic schizophrenic patients with an acutely exacerbated condition who met DSM-IV criteria were included. COX by-products prostaglandin E2 (PGE2) and 15d-prostaglandin J2 (15d-PGJ2) plasma levels were measured by EIA. Peroxisome proliferator-activated receptor gamma (PPARγ) as well as nuclear factor kappaB (NFκB) activity in nuclear extracts from PBMC and expression of its inhibitory subunit IκBα in cytosolic extracts were determined using ELISA-based kits. Schizophrenic patients showed higher plasma levels of pro-inflammatory PGE2 than age-matched controls (p=0.043). On the contrary, levels of anti-inflammatory 15-d-PGJ2 were lower (p=0.004), correlating with a lower expression of its nuclear target, PPARγ in nuclear extracts from PBMC (p=0.001). Although no changes in NFκB activity were observed between patients and healthy controls, the expression of its inhibitory protein IκBα was lower in the patients compared to the controls (p=0.027). These findings suggest that schizophrenia is associated with a systemic imbalance in the plasma levels of pro-inflammatory/anti-inflammatory prostaglandins in favor of the former. Furthermore, the expression and activity of anti-inflammatory PPARγ are diminished in PBMC, which indicates a state of inflammation and blunted anti-inflammatory counterbalancing mechanisms at systemic level in these patients.

The ANKK1 gene associated with addictions is expressed in astroglial cells and upregulated by apomorphine.

BACKGROUND TaqIA, the most widely analyzed genetic polymorphism in addictions, has traditionally been considered a gene marker for association with D2 dopamine receptor gene (DRD2). TaqIA is located in the coding region of the ANKK1 gene that overlaps DRD2 and encodes a predicted kinase ANKK1. The ANKK1 protein nonetheless had yet to be identified. This study examined the ANKK1 expression pattern as a first step to uncover the biological bases of TaqIA-associated phenotypes. METHODS Northern blot and quantitative reverse-transcriptase polymerase chain reaction analyses were performed to analyze the ANKK1 mRNA. To study ANKK1 protein expression, we developed two polyclonal antibodies to a synthetic peptides contained in the putative Ser/Thr kinase domain. RESULTS We demonstrate that ANKK1 mRNA and protein were expressed in the adult central nervous system (CNS) in human and rodents, exclusively in astrocytes. Ankk1 mRNA level in mouse astrocyte cultures was upregulated by apomorphine, suggesting a potential relationship with the dopaminergic system. Developmental studies in mice showed that ANKK1 protein was ubiquitously located in radial glia in the CNS, with an mRNA expression pick around embryonic Day 15. This time expression pattern coincided with that of the Drd2 mRNA. On induction of differentiation by retinoic acid, a sequential expression was found in human neuroblastoma, where ANKK1 was expressed first, followed by that of DRD2. An opposite time expression pattern was found in rat glioma. CONCLUSIONS Spatial and temporal regulation of the expression of ANKK1 suggest an involvement of astroglial cells in TaqIA-related neuropsychiatric phenotypes both during development and adult life.

Gender-specific COMT Val158Met polymorphism association in Spanish schizophrenic patients.

The functional Val158Met polymorphism (rs4680) located at the gene that codes for the catechol‐O‐methyltransferase (COMT) has been extensively investigated in schizophrenia although current data are still controversial. Since COMT activity is sexually dimorphic, we carried out two independent studies in homogeneous samples of male and female Spanish schizophrenic patients. In males, we found an association between the homozygous Val genotype and the disorder, which resembled a recessive model (P = 0.022; odds ratio [OR] = 1.67). This Val homozygotes overrepresentation is produced at the expense of the heterozygous individuals decrease, whilst the Met homozygotes showed no differences when compared controls and patients. As a consequence, the heterozygous genotype in this sample had a protective effect (P = 0.03; OR = 0.65) and a strong deviation from Hardy–Weinberg equilibrium in male cases was observed (P = 0.006). In addition, a 2‐SNP haplotype analysis (rs4818‐Val158Met) confirmed there is an overrepresentation of the different homozygous Val genotypes in the male schizophrenic sample. Regarding females, we did not find any statistically significant association between COMT SNP and schizophrenia. In the light of this we suggest that the Val158Met SNP is involved in risk and protective genotypes for the vulnerability to schizophrenia in Spanish male population.

Association in alcoholic patients between Psychopathic Traits and the additive effect of allelic forms of theCNR1 andFAAH endocannabinoid genes, and the 3′ Region of theDRD2 Gene

Little is known about the genetic factors that underlie the comorbidity between alcohol use disorder and antisocial personality disorder. Previous studies have associated both, dopaminergic and endocannabinoid systems to severe alcoholism with non-adaptive disrupted behaviours. In this work we have examined some gene variants involved in such systems in a sample of alcoholic patients to test whether there is a relationship with antisocial traits. The genetic analysis involved the genotyping of the single nucleotide polymorphism (SNP) TaqIA located nearby theDRD2 gene, the 10-repeat allele of a variable number tandem repeats (VNTR) of theSLC6A3 gene, the C385AFAAH SNP and the 3′-UTR microsatellite ofCNR1 gene. The clinical study was performed in 137 Spanish alcohol dependent males. Antisocial Personality Disorder (DSM-IV) diagnosis was made by applying the International Personality Disorder Examination, and psychopathic traits were evaluated by the Hare’s Psychopathy Checklist Revised (PCL-R). The genotype distribution indicates there is a relationship between the TaqIA SNP,CNR1 andFAAH genes and PCL-R’s Factor 1 in alcoholic patients. This relationship seems to be additive and independent and might be responsible for 11.4% of the variance in this PCL-R subscale. Our results suggest the implication of the dopaminergic and endocannabinoid systems in those processes leading to the comorbidity of alcoholism and antisocial behaviour.

C957T DRD2 polymorphism is associated with schizophrenia in Spanish patients

Objective:  The objective was to confirm whether a homozygous genotype for the C957 allele of the C957T DRD2 gene single nucleotide polymorphism (SNP) is associated with schizophrenia in an independent study population.

The ANKK1 Protein Associated with Addictions has Nuclear and Cytoplasmic Localization and Shows a Differential Response of Ala239Thr to Apomorphine

The TaqIA single-nucleotide polymorphism (SNP), which is the most widely studied genetic polymorphism in addictions, is located at the gene that encodes the RIP kinase ANKK1 near the gene for dopamine receptor D2. The TaqIA SNP is in strong linkage disequilibrium with the SNP rs7118900, which changes the alanine at position 239 to threonine in the ANKK1 protein (Ala239/A2; Thr239/A1). In silico analysis has predicted that this polymorphic substitution creates an additional phosphorylation site in the kinase domain of ANKK1. To investigate the contribution of ANKK1 to the pathophysiology of TaqIA-associated phenotypes, we analyzed transfected HEK293T cells with the human ANKK1-kinaseAla239 and ANKK1-kinaseThr239 variants tagged with GFP. We observed that the ANKK1-kinase is located in both the nucleus and the cytoplasm, suggesting that there is nucleocytoplasmic shuttling of this putative signal transducer. In addition, we found that the Ala239Thr ANKK1-kinase polymorphism exhibited strong expression differences in both the nucleus and the cytoplasm at basal level and when stimulated with the dopamine agonist apomorphine. Specifically, the ANKK1-kinaseThr239 variant showed the highest level of basal protein expression, while ANKK1-kinaseAla239 was 0.64-fold lower. After treatment with apomorphine, ANKK1-kinaseAla239 showed a 2.4-fold increment in protein levels, whereas a 0.67-fold reduction was observed in ANKK1-kinaseThr239. Thus, here we provide the first evidence of functional ANKK1 differences that are marked by TaqIA and could be associated with vulnerability to addiction.

From dopaminergic genes to psychiatric disorders

Individual vulnerability to develop neurological and psychiatric disorders is associated with both genetic and environmental factors. Association studies in patients have explored the contribution of gene variants in the dopaminergic system in these disorders. This system is involved in motor control, endocrinological function, the reward system and cognition. The diverse physiological functions of dopamine are mediated by five different dopamine receptors, encoded by the genesDRD1, DRD2, DRD3, DRD4 andDRD5. These genes have various types of polymorphisms that can produce changes in the genetic product or expression levels. In recent years, the development of new technologies for genetic analysis, and a wider comprehension of the genetic sequences of these genes have increased our understanding of the implications of the dopaminergic system in both health and pathological states. It has also allowed the identification of genetic variants that may represent risk or protection factors for a variety of psychiatric disorders.

Sexually dimorphic interaction between the DRD1 and COMT genes in schizophrenia.

Dopaminergic dysfunction in the prefrontal cortex (PFC) is involved in the pathophysiology of schizophrenia. In the PFC, dopamine signalling largely depends on the D1 receptors, which are coded by the DRD1 gene, and on the regulation of dopamine levels by the enzyme catechol‐O‐methyltransferase (COMT). Here, we investigate the role of DRD1 and its interaction with the COMT gene in schizophrenic patients. In two gender‐limited independent patient and control samples, we genotype five Tag single nucleotide polymorphisms (tagSNPs) of DRD1. The DRD1 SNP and haplotype associations, as well as interaction effects with the Val158Met COMT SNP were analyzed. In the male sample, we found the rs11746641 and rs11749676 DRD1 SNPs were associated with schizophrenia. Haplotype analyses identified the T‐A‐T‐C‐T variant related to a protective effect (P = 0.008) and the G‐G‐T‐C‐C variant that showed a tendency to be a risk factor for the disorder (P = 0.012). A logistic regression analysis revealed a significant pattern of interaction between DRD1 and COMT for both the rs11746641 (P = 0.002) and rs11749676 (P = 4.5 × 10−5) SNPs. DRD1‐associated haplotypes were exclusively related to schizophrenia in the Val homozygous subgroup of patients (T‐A‐T‐C‐T: P = 0.003; G‐G‐T‐C‐C: P = 0.006). In females, none of the DRD1 SNPs were linked to the disorder. Our genetic data suggest that DRD1 and COMT are epistatically associated with protection against and the risk of developing schizophrenia in a gender‐dependent fashion, and support the role of dopamine dysfunction at the PFC in the pathophysiology of this disorder.