Genomewide genetic linkage analysis confirms the presence of susceptibility loci for schizophrenia, on chromosomes 1q32.2, 5q33.2, and 8p21-22 and provides support for linkage to schizophrenia, on chromosomes 11q23.3-24 and 20q12.1-11.23

Expression and clinical significance of U2AF homology motif kinase 1 in oral squamous cell carcinoma

OBJECTIVE

U2AF homology motif kinase 1 (UHMK1) is a newly discovered molecule that may have multiple functions. Recent studies have revealed that UHMK1 had aberrant expression in many tumors and was associated with tumor progression. However, UHMK1 was rarely reported in oral squamous cell carcinoma (OSCC).

STUDY DESIGN

In this study, Western blot, quantitative real-time polymerase chain reaction (PCR), and immunohistochemistry were used to detect the expression of UHMK1 in OSCC and peritumoral non-neoplastic tissues. Then, its relationship with clinicopathologic parameters was analyzed. The Kaplan-Meier method and Cox regression model were used to analyze the effects of UHMK1 expression on the prognosis and survival of OSCC patients.

RESULTS

Our results showed that UHMK1 had higher expression in OSCC tissues compared with in peritumoral non-neoplastic tissues, and its high expression was associated with high TNM stage and lymph node metastasis. High UHMK1 expression was related to short overall and disease-free survival times. Moreover, UHMK1 expression was identified as an independent prognostic factor that influences overall and disease-free survival of OSCC patients.

CONCLUSIONS

High expression of UHMK1 is associated with the poor prognosis of patients, and it can be used as a potential prognostic molecule for OSCC.

Gut Microbiota Metabolite Messengers in Brain Function and Pathology at a View of Cell Type-Based Receptor and Enzyme Reaction

The human gastrointestinal (GI) tract houses a diverse microbial community, known as the gut microbiome comprising bacteria, viruses, fungi, and protozoa. The gut microbiome plays a crucial role in maintaining the body's equilibrium and has recently been discovered to influence the functioning of the central nervous system (CNS). The communication between the nervous system and the GI tract occurs through a two-way network called the gut-brain axis. The nervous system and the GI tract can modulate each other through activated neuronal cells, the immune system, and metabolites produced by the gut microbiome. Extensive research both in preclinical and clinical realms, has highlighted the complex relationship between the gut and diseases associated with the CNS, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This review aims to delineate receptor and target enzymes linked with gut microbiota metabolites and explore their specific roles within the brain, particularly their impact on CNS-related diseases.

RNA-Seq Analysis Reveals Altered Expression of Cell Adhesion-Related Genes Following PZR Knockout in Lung Cancer Cells

Protein zero related (PZR) serves as a substrate and anchor protein for SHP-2, the product of the proto-oncogene PTPN11 that is frequently mutated in cancers. The expression level of PZR is elevated in various cancers, which is correlated with an unfavorable prognosis. The role of PZR in lung cancer is not fully studied. To investigate how PZR affects signaling pathways involved in LUAD development, we utilized the CRISPR technology to knock out PZR expression in SPC-A1 lung adenocarcinoma cells and then conducted RNA sequencing to profile the transcriptome. Our results showed that 226 genes exhibited differential expressions in PZR-knockout SPC-A1 cells vs wild-type cells. Many of the genes encode proteins involved in cell adhesion, migration, actin cytoskeleton organization, and regulation of cell shape. Furthermore, our experimental data showed that PZR-knockout SPC-A1 cells displayed faster attachment to tissue culture dishes and slower detachment from the dishes upon EDTA treatment. The data suggest an important role of PZR in cell-matrix interaction and may provide new insights into the signaling events that regulate cancer development.

BACE1-dependent metabolism of neuregulin 1: Bridging the gap in explaining the occurrence of schizophrenia-like symptoms in Alzheimer's disease with psychosis?

Alzheimer's disease is a neurodegenerative disease mainly characterized by cortico-neuronal atrophy, impaired memory and other cognitive declines. On the other hand, schizophrenia is a neuro-developmental disorder with an overtly active central nervous system pruning system resulting into abrupt connections with common symptoms including disorganised thoughts, hallucination and delusion. Nevertheless, the fronto-temporal anomaly presents itself as a common denominator for the two pathologies. There is even a strong presumption of increased risk of developing co-morbid dementia for schizophrenic individuals and psychosis for Alzheimer's disease patients, overall leading to a further deteriorated quality of life. However, convincing proofs of how these two disorders, although very distant from each other when considering their aetiology, develop coexisting symptoms is yet to be resolved. At the molecular level, the two primarily neuronal proteins β-amyloid precursor protein and neuregulin 1 have been considered in this relevant context, although the conclusions are for the moment only hypotheses. In order to propose a model for explaining the psychotic schizophrenia-like symptoms that sometimes accompany AD-associated dementia, this review projects out on the similar sensitivity shared by these two proteins regarding their metabolism by the β-site APP cleaving enzyme 1.

Gene expression meta-analysis in patients with schizophrenia reveals up-regulation of RGS2 and RGS16 in Brodmann Area 10

Regulator of G-protein signalling (RGS) proteins inhibit signalling by G-protein-coupled receptors (GPCRs). GPCRs mediate the functions of several important neurotransmitters and serve as targets of many anti-psychotics. RGS2, RGS4, RGS5 and RGS16 are located on chromosome 1q23.3-31, a locus found to be associated with schizophrenia. Although previous gene expression analysis detected down-regulation of RGS4 expression in brain samples of patients with schizophrenia, the results were not consistent. In the present study, we performed a systematic meta-analysis of differential RGS2, RGS4, RGS5 and RGS16 expression in Brodmann Area 10 (BA10) samples of patients with schizophrenia and from healthy controls. Two microarray datasets met the inclusion criteria (overall, 41 schizophrenia samples and 38 controls were analysed). RGS2 and RGS16 were found to be up-regulated in BA10 samples of individuals with schizophrenia, whereas no differential expression of RGS4 and RGS5 was detected. Analysis of dorso-lateral prefrontal cortex samples of the CommonMind Consortium (258 schizophrenia samples vs. 279 controls) further validated the results. Given their central role in inactivating G-protein-coupled signalling pathways, our results suggest that differential gene expression might lead to enhanced inactivation of G-protein signalling in schizophrenia. This, in turn, suggests that additional studies are needed to further explore the consequences of the differential expression we detected, this time at the protein and functional levels.

Genomic-Analysis-Oriented Drug Repurposing in the Search for Novel Antidepressants

From inadequate prior antidepressants that targeted monoamine neurotransmitter systems emerged the discovery of alternative drugs for depression. For instance, drugs targeted interleukin 6 receptor (IL6R) in inflammatory system. Genomic analysis-based drug repurposing using single nucleotide polymorphism (SNP) inclined a promising method for several diseases. However, none of the diseases was depression. Thus, we aimed to identify drug repurposing candidates for depression treatment by adopting a genomic-analysis-based approach. The 5885 SNPs obtained from the machine learning approach were annotated using HaploReg v4.1. Five sets of functional annotations were applied to determine the depression risk genes. The STRING database was used to expand the target genes and identify drug candidates from the DrugBank database. We validated the findings using the ClinicalTrial.gov and PubMed databases. Seven genes were observed to be strongly associated with depression (functional annotation score = 4). Interestingly, IL6R was auspicious as a target gene according to the validation outcome. We identified 20 drugs that were undergoing preclinical studies or clinical trials for depression. In addition, we identified sarilumab and satralizumab as drugs that exhibit strong potential for use in the treatment of depression. Our findings indicate that a genomic-analysis-based approach can facilitate the discovery of drugs that can be repurposed for treating depression.

The concentration of MMP-9 and the effects of intravenous anaesthetics on the efficacy of electroconvulsive therapy in patients with drug-resistant depression

Introduction: This study attempts to assess the concentration of intracellular matrix metalloproteinase (MMP-9) before and after the treatment of depressive episodes with ECT therapy and also to correlate the concentration of this enzyme with the use of commonly used general anaesthetics.

Materials and methods: The study group comprised of 37 patients hospitalized in the Department of Adult Psychiatry in Poznan, with a diagnosis of episodes of drug-resistant depression during the course of bipolar and unipolar affective disorders, and who were being treated using electroconvulsive therapy. For the purpose of inducing anaesthesia during the procedure propofol was used in 10 cases, thiopental in 9 cases. Propofol was alternated with ketamine in a further 10 cases and thiopental was alternated with ketamine in another 9 cases. In order to assess the intensity of depression symptoms, the 17 point Hamilton depression scale was used, immediately before commencing ECT therapy, and one day after its completion. The serum concentration of MMP-9 was determined before and after the series of ECT treatments. In order to assess the serum concentration of MMP-9, an ELISA immunoenzymatic method was applied.

Results: In this study, a significant reduction of MMP-9 concentration was noted after therapy, relative to the starting concentration, in the serum of patients suffering from depressive episodes resulting from either unipolar or bipolar affective disorders. These results correlated with improved psychiatric state, as assessed by the Hamilton scale. A significantly lower MMP-9 concentration was noted in the serum of patients given alternating thiopental and ketamine anaesthesia.

Conclusions: This study suggests the importance of the enzyme as a biological marker for the effective treatment of depression. Furthermore, the choice of general anaesthetic applied during ECT also plays a role.

The Variants at APOA1 and APOA4 Contribute to the Susceptibility of Schizophrenia With Inhibiting mRNA Expression in Peripheral Blood Leukocytes

Objective: Abnormal lipid metabolism has a close link to the pathophysiology of schizophrenia (SZ). This study mainly aimed to evaluate the association of variants at apolipoprotein A1 (APOA1) and APOA4 with SZ in a Chinese Han population.

Methods: The rs5072 of APOA1 and rs1268354 of APOA4 were examined in a case–control study involving 2,680 patients with SZ from the hospital and 2,223 healthy controls screened by physical examination from the community population. The association was estimated with the odds ratio (OR) and 95% confidence intervals (95% CIs) by logistic regression. The APOA1 and APOA4 messenger RNA (mRNA) in peripheral blood leukocytes were measured by real-time PCR and compared between SZ cases and controls. Serum apoA1 levels were detected by turbidimetric inhibition immunoassay and high-density lipoprotein cholesterol (HDL-C) levels were detected by the homogeneous method.

Results: Both of the rs5072 of APOA1 and rs1268354 of APOA4 had statistically significant associations with SZ. After adjustment for age and sex, ORs (95% CIs) of the additive model of rs5072 and rs1268354 were 0.82 (0.75–0.90) and 1.120 (1.03–1.23), and p-values were 3.22 × 10⁻⁵ and 0.011, respectively. The association of rs5072 with SZ still presented statistical significance even after Bonferroni correction (p-value×6). SZ patients during the episode presented lower levels of apoA1, HDL-C, mRNA of APOA1 common variants and transcript variant 4, and APOA4 mRNA than controls (p < 0.01) while SZ patients in remission showed a significantly decreased APOA1 transcript variant 3 expression level and increased APOA4 mRNA expression level (p < 0.01). mRNA expression levels of APOA1 transcript variant 4 significantly increased with the variations of rs5072 in SZ during the episode (p_trend = 0.017). After the SZ patients received an average of 27.50 ± 9.90 days of antipsychotic treatment, the median (interquartile) of serum apoA1 in the SZ episode significantly increased from 1.03 (1.00.1.20) g/L to 1.08 (1.00.1.22) g/L with the p-value of 0.044.

Conclusion: Our findings suggest that the genetic variations of APOA1 rs5072 and APOA4 rs1268354 contribute to the susceptibility of SZ, and the expression levels of APOA1 and APOA4 mRNA of peripheral blood leukocytes decreased in SZ patients during the episode while APOA4 increased after antipsychotic treatment.

Impact of NRG1 HapICE gene variants on digit ratio and dermatoglyphic measures in schizophrenia

Multiple lines of evidence have suggested a potential role of Neuregulin-1 (NRG1) in the neurodevelopmental pathogenesis of schizophrenia. Interaction between genetic risk variants present within NRG1 locus and non-specific gestational putative insults can significantly impair crucial processes of brain development. Such genetic effects can be analyzed through the assessment of digit ratio and dermatoglyphic patterns. We examined the role of two well-replicated polymorphisms of NRG1 (SNP8NRG221533 and SNP8NRG243177) on schizophrenia risk and its probable impact on the digit ratio and dermatoglyphic measures in patients (N = 221) and healthy controls (N = 200). In schizophrenia patients, but not in healthy controls, a significant association between NRG1 SNP8NRG221533 C/C genotype with lower left 2D:4D ratio, as well as with higher FA_T_bcRC and DA_T_bcRC. The substantial effect of SNP8NRG221533 on both digit ratio and dermatoglyphic measures suggest a potential role for NRG1 gene variants on neurodevelopmental pathogenesis of schizophrenia.

Kynurenine pathway in Parkinson's disease-An update

Parkinson's disease (PD) is a complex multi-factorial neurodegenerative disorder where various altered metabolic pathways contribute to the progression of the disease. Tryptophan (TRP) is a major precursor in kynurenine pathway (KP) and it has been discussed in various in vitro studies that the metabolites quinolinic acid (QUIN) causes neurotoxicity and kynurenic acid (KYNA) acts as neuroprotectant respectively. More studies are also focused on the effects of other KP metabolites and its enzymes as it has an association with ageing and PD pathogenesis. Until now, very few studies have targeted the role of genetic mutations in abnormal KP metabolism in adverse conditions of PD. Therefore, the present review gives an updated research studies on KP in connection with PD. Moreover, the review emphasizes on the urge for the development of biomarkers and also this would be an initiative in generating an alternative therapeutic approach for PD.

CRMP2 mediates GSK3β actions in the striatum on regulating neuronal structure and mania-like behavior

BACKGROUND

Genetic and physiological studies have implicated the striatum in bipolar disorder (BD). Although Glycogen synthase kinase 3 beta (GSK3β) has been suggested to play a role in the pathophysiology of BD since it is inhibited by lithium, it remains unknown how GSK3β activity might be involved. Therefore we examined the functional roles of GSK3β and one of its substrates, CRMP2, within the striatum.

METHODS

Using CRISPR-Cas9 system, we specifically ablated GSK3β in the striatal neurons in vivo and in vitro. Sholl analysis was performed for the structural studies of medium spiny neurons (MSNs) and amphetamine-induced hyperlocomotion was measured to investigate the effects of gene ablations on the mania-like symptom of BD.

RESULTS

GSK3β deficiency in cultured neurons and in neurons of adult mouse brain caused opposite patterns of neurite changes. Furthermore, specific knockout of GSK3β in the MSNs of the indirect pathway significantly suppressed amphetamine-induced hyperlocomotion. We demonstrated that these phenotypes of GSK3β ablation were mediated by CRMP2, a major substrate of GSK3β.

LIMITATIONS

Amphetamine-induced hyperlocomotion only partially recapitulate the symptoms of BD. It requires further study to examine whether abnormality in GSK3β or CRMP2 is also involved in depression phase of BD. Additionally, we could not confirm whether the behavioral changes observed in GSK3β-ablated mice were indeed caused by the cellular structural changes observed in the striatal neurons.

CONCLUSION

Our results demonstrate that GSK3β and its substrate CRMP2 critically regulate the neurite structure of MSNs and their functions specifically within the indirect pathway of the basal ganglia network play a critical role in manifesting mania-like behavior of BD. Moreover, our data also suggest lithium may exert its effect on BD through a GSK3β-independent mechanism, in addition to the GSK3β inhibition-mediated mechanism.

A normal genetic variation modulates synaptic MMP-9 protein levels and the severity of schizophrenia symptoms

Matrix metalloproteinase 9 (MMP‐9) has recently emerged as a molecule that contributes to pathological synaptic plasticity in schizophrenia, but explanation of the underlying mechanisms has been missing. In the present study, we performed a phenotype‐based genetic association study (PGAS) in > 1,000 schizophrenia patients from the Göttingen Research Association for Schizophrenia (GRAS) data collection and found an association between the MMP‐9 rs20544 C/T single‐nucleotide polymorphism (SNP) located in the 3′untranslated region (UTR) and the severity of a chronic delusional syndrome. In cultured neurons, the rs20544 SNP influenced synaptic MMP‐9 activity and the morphology of dendritic spines. We demonstrated that Fragile X mental retardation protein (FMRP) bound the MMP‐9 3′UTR. We also found dramatic changes in RNA structure folding and alterations in the affinity of FMRP for MMP‐9 RNA, depending on the SNP variant. Finally, we observed greater sensitivity to psychosis‐related locomotor hyperactivity in Mmp‐9 heterozygous mice. We propose a novel mechanism that involves MMP‐9‐dependent changes in dendritic spine morphology and the pathophysiology of schizophrenia, providing the first mechanistic insights into the way in which the single base change in the MMP‐9 gene (rs20544) influences gene function and results in phenotypic changes observed in schizophrenia patients.

Genetic alterations affecting the genes encoding the enzymes of the kynurenine pathway and their association with human diseases

Tryptophan is metabolized primarily via the kynurenine pathway (KP), which involves several enzymes, including indoleamine 2,3-dioxygenase, tryptophan 2,3 dioxygenase (TDO), kynurenine aminotransferases (KATs), kynurenine monooxygenase (KMO) etc. The majority of metabolites are neuroactive: some of them, such as kynurenic acid, show neuroprotective effects, while others contribute to free radical production, leading to neurodegeneration. Imbalance of the pathway is assumed to contribute to the development of several neurodegenerative diseases, psychiatric disorders, migraine and multiple sclerosis. Our aim was to summarize published data on genetic alterations of enzymes involved in the KP leading to disturbances of the pathway that can be related to different diseases. To achieve this, a PubMed literature search was performed for publications on genetic alterations of the KP enzymes upto April 2017. Several genetic alterations of the KP have been identified and have been proposed to be associated with diseases. Here we must emphasize that despite the large number of recognized genetic alterations, the number of firmly established causal relations with specific diseases is still small. The realization of this by those interested in the field is very important and finding such connections should be a major focus of related research. Polymorphisms of the genes encoding the enzymes of the KP have been associated with autism, multiple sclerosis and schizophrenia, and were shown to affect the immune response of patients with bacterial meningitis, just to mention a few. To our knowledge, this is the first comprehensive review of the genetic alterations of the KP enzymes. We believe that the identification of genetic alterations underlying diseases has great value regarding both treatment and diagnostics in precision medicine, as this work can promote the understanding of pathological mechanisms, and might facilitate medicinal chemistry approaches to substitute missing components or correct the disturbed metabolite balance of KP.

A gene-based review of RGS4 as a putative risk gene for psychiatric illness

Considerable efforts have been made to characterize RGS4 as a potential candidate gene for schizophrenia. Investigations span across numerous modalities and include explorations of genetic risk associations, mRNA and protein levels in the brain, and functionally relevant interactions with other candidate genes as well as links to schizophrenia relevant neural phenotypes. While these lines of investigations have yielded partially inconsistent findings, they provide a perspective on RGS4 as an important part of a larger biological system contributing to schizophrenia risk. This gene-based review aims to provide a comprehensive overview of published data from different experimental modalities and discusses the current knowledge of RGS4's systems-biological impact on the schizophrenia pathology.

Minor allele C of rs12807809 polymorphism in NRGN contributes to the severity of psychosis in patients with Schizophrenia in South Indian population

Schizophrenia (SCZ) as a severe and complex neuropsychiatric disorder and is characterized by positive symptoms, negative symptoms and cognitive dysfunctions. Genome-wide association studies (GWAS) have identified a strong association between the single nucleotide polymorphism (SNP) rs12807809 upstream of Neurogranin (NRGN) in a European population. This evidence prompted us to conduct an association study among 1005 schizophrenia cases and 1069 controls in a South Indian Population using TaqMan Allelic discrimination method. We observed an association of rs12807809 with SCZ in this study population. Allele frequencies and genotype frequencies of rs12807809 showed significant differences between cases and control subjects [p=0.0019; OR=0.69; 95% CI=(0.55-0.87)] and (p=0.0062). Further Genotype-Phenotype correlation revealed a moderate association of rs12807809 with flat affect (p=0.039) and Hallucinations (p=0.012). The ancestral non-risk C allele contributes to the severity of psychosis (p=0.039) in this population.

Emerging Synaptic Molecules as Candidates in the Etiology of Neurological Disorders

Synapses are complex structures that allow communication between neurons in the central nervous system. Studies conducted in vertebrate and invertebrate models have contributed to the knowledge of the function of synaptic proteins. The functional synapse requires numerous protein complexes with specialized functions that are regulated in space and time to allow synaptic plasticity. However, their interplay during neuronal development, learning, and memory is poorly understood. Accumulating evidence links synapse proteins to neurodevelopmental, neuropsychiatric, and neurodegenerative diseases. In this review, we describe the way in which several proteins that participate in cell adhesion, scaffolding, exocytosis, and neurotransmitter reception from presynaptic and postsynaptic compartments, mainly from excitatory synapses, have been associated with several synaptopathies, and we relate their functions to the disease phenotype.

Association between NAT2 polymorphisms and the risk of schizophrenia in a Northern Chinese Han population

The gene that encodes N-acetyltransferase 2 (NAT2), an enzyme that plays a crucial role in the metabolism of many drugs and xenobiotics, is located on chromosome 8p22, one of the most convictive susceptibility loci of schizophrenia. NAT2 genetic polymorphisms lead to various enzyme acetylation phenotypes. In the present study, six selected NAT2 exonic single nucleotide polymorphisms were genotyped in an independent case-control sample of a Northern Chinese Han population to verify the possible association between NAT2 and schizophrenia. Three (rs1801280T/341C, rs1799930/G590A, and rs1208/A803G) of the six single nucleotide polymorphisms showed significant allele frequency differences between the case and the control groups after rigorous Bonferroni correction. One protective fast-acetylation haplotype (NAT2*4) and two risk slow acetylation haplotypes (NAT2*5B and NAT2*6A) were discovered to be associated with schizophrenia. Our results indicate that NAT2 may be a susceptibility gene for schizophrenia in this Chinese Han population, and the risk haplotypes might cause the impairment of NAT2 in metabolizing neurotoxic substances.

Association between RGS4 variants and psychotic-like experiences in nonclinical individuals

The psychosis phenotype is expressed across a continuum known as schizotypy, which ranges from personality variation through subclinical symptoms to severe psychopathology. The study of subclinical manifestations in non-affected individuals minimizes confounding factors associated with the clinical phenotype and facilitates the differentiation of dimension-specific etiological mechanisms. The aim of the present study was to investigate the association between the variation in the regulator of G-protein signaling 4 (RGS4) gene, a putative candidate gene for psychosis previously associated with schizophrenia endophenotypes, and psychotic-like experiences (PLEs). In total, 808 healthy individuals completed the community assessment of psychic experiences (CAPE) to measure positive and negative PLEs and provided a DNA sample. Two RGS4 single-nucleotide polymorphisms (SNPs) (rs951436 [SNP4] and rs2661319 [SNP18]) were genotyped. Analyses of covariance (ANCOVA) were used to explore the association of positive and negative PLEs with RGS4 variation. Our results showed associations of positive and negative PLEs with the two polymorphisms studied: subjects with the T allele (SNP4) and the A allele (SNP18) had higher scores on both the positive and the negative dimensions. Haplotypic analyses supported these results, showing the highest scores in those with the TA haplotype (SNP4-SNP18). The RGS4 variants might exert gene-specific modulating effects on psychosis proneness.

Family-based association study of interleukin 10 (IL10) and interleukin 10 receptor alpha (IL10RA) functional polymorphisms in schizophrenia in Polish population

Schizophrenia is a heterogeneous disorder and its etiology remains incompletely elucidated. Among possible causes, immunological factors have been implicated in its pathogenesis and course. Interleukin-10 (IL10) and it's receptor IL10RA may play an important role for immunological aspects in etiologies of major psychiatric disorders including schizophrenia. The aim of this study was to perform a transmission disequilibrium test (TDT) on a group of 146 schizophrenia trios from the Polish population. Functional polymorphisms from IL10 (rs1800872, rs1800871, rs1800896, rs1800890, and rs6676671) and IL10RA (rs3135932 and rs2229113) genes were analyzed. A lack of association with schizophrenia was detected for IL10 and IL10RA single polymorphisms and haplotypes.

The role of Pannexin gene variants in schizophrenia: systematic analysis of phenotypes

Pannexins are a group of brain-expressed channel proteins thought to be regulators of schizophrenia-linked pathways including glutamate release, synaptic plasticity and neural stem proliferation. We got evidence for linkage of a catatonic phenotype to the PANX2 locus in a family study. Aim of our study was to evaluate the role of Pannexins in schizophrenia and clinical phenotypes, particularly with regard to periodic catatonia. We genotyped six single-nucleotide polymorphisms at PANX1, five at PANX2 and three at PANX3 in 1173 German cases with schizophrenia according to DSM-5 and 480 controls. Our sample included 338 cases with periodic catatonia corresponding to Leonhard's classification. Association with schizophrenia according to DSM-5 was limited to genotype rs4838858-TT [p = 0.02, odds ratio (OR) 3.1] and haplotype rs4838858T-rs5771206G (p = 0.02, OR 2.7) at PANX2. We found no significant association with clinical phenotypes. Our limited findings do not support a major contribution of PANX1-3 to disease risk of schizophrenia according to DSM-5. We cannot confirm an association of the PANX2 loci at chromosome 22q13 with periodic catatonia.

Association of HOMER1 rs2290639 with suicide attempts in Hong Kong Chinese and the potentially functional role of this polymorphism

OBJECTIVE

Animal evidence and genetic studies suggest that HOMER1 (homer homolog 1) is involved in the etiology of suicidal behavior and major depression disorder (MDD). However, most of genetic studies were performed in Caucasians and the potentially functional role of associated polymorphisms in HOMER1 was seldom reported. The purpose of this study was to investigate the association of a HOMER1 polymorphism rs2290639 with suicide attempts (SA) and MDD in Hong Kong Chinese, and then briefly elucidate the potentially functional role of the associated polymorphism.

METHODS

NEO personality inventory, impulsiveness and depression rating scales were completed by the subjects. The association studies of HOMER1 rs2290639 with SA or MDD were performed by case-control association studies. The bioinformatics analyses were adapted to predict potential transcription factors binding sites for the associated polymorphism.

RESULTS

The association studies and meta-analysis suggested that the HOMER1 rs2290639 was significantly associated with susceptibility to SA but seemed not to be associated with MDD in Hong Kong Chinese. This polymorphism might affect the transcription of the HOMER1 gene through interacting with a reliable transcription factor as found by three of four bioinformatics tools. In addition, close correlations between impulsiveness and NEO personality five factors were found in SA and MDD patients, which provide a possible way to assess the impulsiveness of patients through subjects' personality profiles for Hong Kong Chinese.

CONCLUSIONS

The HOMER1 rs2290639 polymorphism was significantly associated with susceptibility to SA in Hong Kong Chinese affected by psychiatric disorders, which might be explained by the potentially functional role of this polymorphism.

Brain-specific Crmp2 deletion leads to neuronal development deficits and behavioural impairments in mice

Several genome- and proteome-wide studies have associated transcription and translation changes of CRMP2 (collapsing response mediator protein 2) with psychiatric disorders, yet little is known about its function in the developing or adult mammalian brain in vivo. Here we show that brain-specific Crmp2 knockout (cKO) mice display molecular, cellular, structural and behavioural deficits, many of which are reminiscent of neural features and symptoms associated with schizophrenia. cKO mice exhibit enlarged ventricles and impaired social behaviour, locomotor activity, and learning and memory. Loss of Crmp2 in the hippocampus leads to reduced long-term potentiation, abnormal NMDA receptor composition, aberrant dendrite development and defective synapse formation in CA1 neurons. Furthermore, knockdown of crmp2 specifically in newborn neurons results in stage-dependent defects in their development during adult hippocampal neurogenesis. Our findings reveal a critical role for CRMP2 in neuronal plasticity, neural function and behavioural modulation in mice.

From Linkage Studies to Epigenetics: What We Know and What We Need to Know in the Neurobiology of Schizophrenia

Schizophrenia is a complex psychiatric disorder characterized by the presence of positive, negative, and cognitive symptoms that lacks a unifying neuropathology. In the present paper, we will review the current understanding of molecular dysregulation in schizophrenia, including genetic and epigenetic studies. In relation to the latter, basic research suggests that normal cognition is regulated by epigenetic mechanisms and its dysfunction occurs upon epigenetic misregulation, providing new insights into missing heritability of complex psychiatric diseases, referring to the discrepancy between epidemiological heritability and the proportion of phenotypic variation explained by DNA sequence difference. In schizophrenia the absence of consistently replicated genetic effects together with evidence for lasting changes in gene expression after environmental exposures suggest a role of epigenetic mechanisms. In this review we will focus on epigenetic modifications as a key mechanism through which environmental factors interact with individual's genetic constitution to affect risk of psychotic conditions throughout life.

Polymorphisms in NRGN are associated with schizophrenia, major depressive disorder and bipolar disorder in the Han Chinese population

BACKGROUND

The NRGN gene locates on 11q24 and encodes a postsynaptic protein kinase substrate that binds calmodulin in the absence of calcium. In a previous genome-wide association study of schizophrenia in the Caucasian population, rs12807809 of NRGN was found to be significantly associated with schizophrenia, moreover, it was further found to be associated with bipolar disorder.

METHODS

We recruited 1248 schizophrenia cases, 1344 bipolar disorder cases, 1056 major depressive disorder cases, and 1248 healthy controls from Han Chinese population. Rs12807809 and another two tag SNPs of NRGN were genotyped and analyzed in three diseases respectively. A meta-analysis of rs12807809 was also conducted to verify its association with schizophrenia in Han Chinese population.

RESULTS

Rs7113041 was associated with bipolar disorder (odds ratio, 95% confidence interval (OR, 95% CI)=1.194, 1.032-1.383; Pgenotype=0.0126), and rs12278912 was associated with major depressive disorder (OR, 95% CI=0.789, 0.673-0.924; Pallele=0.0102, Pgenotype=0.0399) after Bonferroni correction. The "GA" haplotype of rs7113041-rs12278912 was significantly associated with schizophrenia, major depressive disorder and bipolar disorder (corresponding P values were 2.85E-04, 3.00E-03, and 5.40E-04 after Bonferroni correction).

LIMITATIONS

Despite the association between NRGN and psychoses we have found, we failed to validate the positive variant rs12807809, which was reported in the Caucasian genome-wide association study both in our single site association test and the meta-analysis. Functional studies are needed to illuminate the role of NRGN in the pathogenesis of these mental disorders.

CONCLUSIONS

Our findings prove that NRGN is a shared susceptibility gene of schizophrenia, major depression and bipolar disorder in Han Chinese, and this might provide a new target for the diagnosis and treatment of these mental disorders.

Genetic association between NRG1 and schizophrenia, major depressive disorder, bipolar disorder in Han Chinese population

Schizophrenia, major depressive disorder, and bipolar disorder are three major psychiatric disorders affecting around 0.66%, 3.3%, and 1.5% of the Han Chinese population respectively. Several genetic linkage analyses and genome wide association studies identified NRG1 as a susceptibility gene of schizophrenia, which was validated by its role in neurodevelopment, glutamate, and other neurotransmitter receptor expression regulation. To further investigate whether NRG1 is a shared risk gene for major depressive disorder, bipolar disorder as well as schizophrenia, we performed an association study among 1,248 schizophrenia cases, 1,056 major depression cases, 1,344 bipolar disorder cases, and 1,248 controls. Totally 15 tag SNPs were genotyped and analyzed, and no population stratification was found in our sample set. Among the sites, rs4236710 (corrected Pgenotye  = 0.015) and rs4512342 (Pallele  = 0.03, Pgenotye  = 0.045 after correction) were associated with schizophrenia, and rs2919375 (corrected Pgenotye  = 0.004) was associated with major depressive disorder. The haplotype rs4512342-rs6982890 showed association with schizophrenia (P = 0.03 for haplotype "TC" after correction), and haplotype rs4531002-rs11989919 proved to be a shared risk factor for both major depressive disorder ("CC": corrected P = 0.009) and bipolar disorder ("CT": corrected P = 0.003). Our results confirmed that NRG1 was a shared common susceptibility gene for major mental disorders in Han Chinese population.

Exome Sequence Data From Multigenerational Families Implicate AMPA Receptor Trafficking in Neurocognitive Impairment and Schizophrenia Risk

Schizophrenia is a mental disorder characterized by impairments in behavior, thought, and neurocognitive performance. We searched for susceptibility loci at a quantitative trait locus (QTL) previously reported for abstraction and mental flexibility (ABF), a cognitive function often compromised in schizophrenia patients and their unaffected relatives. Exome sequences were determined for 134 samples in 8 European American families from the original linkage study, including 25 individuals with schizophrenia or schizoaffective disorder. At chromosome 5q32-35.3, we analyzed 407 protein-altering variants for association with ABF and schizophrenia status. For replication, significant, Bonferroni-corrected findings were tested against cognitive traits in Mexican American families (n = 959), as well as interrogated for schizophrenia risk using GWAS results from the Psychiatric Genomics Consortium (PGC). From the gene SYNPO, rs6579797 (MAF = 0.032) shows significant associations with ABF (P = .015) and schizophrenia (P = .040), as well as jointly (P = .0027). In the Mexican American pedigrees, rs6579797 exhibits significant associations with IQ (P = .011), indicating more global effects on neurocognition. From the PGC results, other SYNPO variants were identified with near significant effects on schizophrenia risk, with a local linkage disequilibrium block displaying signatures of positive selection. A second missense variant within the QTL, rs17551608 (MAF = 0.19) in the gene WWC1, also displays a significant effect on schizophrenia in our exome sequences (P = .038). Remarkably, the protein products of SYNPO and WWC1 are interaction partners involved in AMPA receptor trafficking, a brain process implicated in synaptic plasticity. Our study reveals variants in these genes with significant effects on neurocognition and schizophrenia risk, identifying a potential pathogenic mechanism for schizophrenia spectrum disorders.

Altered expression of mRNA profiles in blood of early-onset schizophrenia

To identify gene expression abnormalities in schizophrenia (SZ), we generated whole-genome gene expression profiles using microarrays on peripheral blood mononuclear cells (PBMCs) from 18 early-onset SZ cases and 12 controls. We detected 84 transcripts differentially expressed by diagnostic status, with 82 genes being upregulated and 2 downregulated. We identified two SZ associated gene coexpression modules (green and red), including 446 genes . The green module is positively correlated with SZ, encompassing predominantly up-regulated genes in SZ; while the red module was negatively correlated with disease status, involving mostly nominally down-regulated genes in SZ. The olfactory transduction pathway was the most enriched pathways for the genes within the two modules. The expression levels of several hub genes, including AKT1, BRCA1, CCDC134, UBD, and ZIC2 were validated using real-time quantitative PCR. Our findings indicate that mRNA coexpression abnormalities may serve as a promising mechanism underlying the development of SZ.

Role of the Neuregulin Signaling Pathway in Nicotine Dependence and Co-morbid Disorders

Smoking is currently the leading cause of preventable death in the United States and is responsible for over four million deaths annually worldwide. Therefore, there is a vast clinical unmet need with regards to therapeutics targeting smoking cessation. This is even more apparent when examining smokers co-morbid with psychiatric illness, as rates of smoking in this population are ~4× higher than in the general population. Examining common genetic and molecular signaling pathways impinging upon both smoking behavior and psychiatric illness will lead to a better understanding of co-morbid disorders and potential development of novel therapeutics. Studies have implicated the Neuregulin Signaling Pathway in the pathophysiology of a number of psychiatric illnesses. Additionally, recent studies have also shown an association between the Neuregulin Signaling Pathway and smoking behaviors. This review outlines basic mechanisms of the Neuregulin Signaling Pathway and how it may be exploited for precision medicine approaches in treating nicotine dependence and mental illness.

CRMPs: critical molecules for neurite morphogenesis and neuropsychiatric diseases

Neuronal polarity and spatial rearrangement of neuronal processes are central to the development of all mature nervous systems. Recent studies have highlighted the dynamic expression of Collapsin-Response-Mediator Proteins (CRMPs) in neuronal dendritic/axonal compartments, described their interaction with cytoskeleton proteins, identified their ability to activate L- and N-type voltage-gated calcium channels (VGCCs) and delineated their crucial role as signaling molecules essential for neuron differentiation and neural network development and maintenance. In addition, evidence obtained from genome-wide/genetic linkage/proteomic/translational approaches revealed that CRMP expression is altered in human pathologies including mental (schizophrenia and mood disorders) and neurological (Alzheimer's, prion encephalopathy, epilepsy and others) disorders. Changes in CRMPs levels have been observed after psychotropic treatments, and disrupting CRMP2 binding to calcium channels blocked neuropathic pain. These observations, altogether with those obtained from genetically modified mice targeting individual CRMPs and RNA interference approaches, pave the way for considering CRMPs as potential early disease markers and modulation of their activity as therapeutic strategy for disorders associated with neurite abnormalities.

Matrix Metalloproteinase-9 as a Novel Player in Synaptic Plasticity and Schizophrenia

Recent findings implicate alterations in glutamate signaling, leading to aberrant synaptic plasticity, in schizophrenia. Matrix metalloproteinase-9 (MMP-9) has been shown to regulate glutamate receptors, be regulated by glutamate at excitatory synapses, and modulate physiological and morphological synaptic plasticity. By means of functional gene polymorphism, gene responsiveness to antipsychotics and blood plasma levels MMP-9 has recently been implicated in schizophrenia. This commentary critically reviews these findings based on the hypothesis that MMP-9 contributes to pathological synaptic plasticity in schizophrenia.

Influence of NRGN rs12807809 polymorphism on symptom severity in individuals with schizophrenia in the Han population but not the Zhuang population of south China

BACKGROUND

NRGN is one of the most promising candidate genes for schizophrenia based on function and position. Therefore, this study aimed to examine the genetic association of this polymorphism with schizophrenia in the Zhuang and Han populations of south China. Subjects and methods A total of 282 patients (188 Han and 94 Zhuang) and 282 healthy subjects (188 Han and 94 Zhuang) were recruited. Of these, 246 schizophrenia patients underwent an assessment of psychotic symptoms using the Positive and Negative Syndrome Scale (PANSS). A TaqMan genotyping assay method was used to determine the genotypes.

RESULTS

We did not find a significant association of rs12807809 polymorphism with schizophrenia in the total pooled samples, or in the separate ethnic groups. However, in Han schizophrenia patients, quantitative data analyses showed that the CC genotype of the rs12807809 polymorphism was associated with PANSS aggression subscale score and activation subscale score. Furthermore, carriers of the C allele of rs12807809 polymorphism among Han schizophrenia patients had higher scores of general, activation, depression, aggression, and global symptoms than the T allele carriers.

CONCLUSION

In conclusion rs12807809 polymorphism may not contribute to the risk of schizophrenia but influence the clinical symptoms of schizophrenia in the Han population.

Characterization of a Novel Mutation in SLC1A1 Associated with Schizophrenia

We have recently described a hemi-deletion on chromosome 9p24.2 at the SLC1A1 gene locus and its co-segregation with schizophrenia in an extended Palauan pedigree. This finding represents a point of convergence for several pathophysiological models of schizophrenia. The present report sought to characterize the biological consequences of this hemi-deletion. Dual luciferase assays demonstrated that the partially deleted allele (lacking exon 1 and the native promoter) can drive expression of a 5'-truncated SLC1A1 using sequence upstream of exon 2 as a surrogate promoter. However, confocal microscopy and electrophysiological recordings demonstrate that the 5'-truncated SLC1A1 lacks normal membrane localization and glutamate transport ability. To identify downstream consequences of the hemi-deletion, we first used a themed qRT-PCR array to compare expression of 84 GABA and glutamate genes in RNA from peripheral blood leukocytes in deletion carriers (n = 11) versus noncarriers (n = 8) as well as deletion carriers with psychosis (n = 5) versus those without (n = 3). Then, targeted RNA-Seq (TREx) was used to quantify expression of 375 genes associated with neuropsychiatric disorders in HEK293 cells subjected to either knockdown of SLC1A1 or overexpression of full-length or 5'-truncated SLC1A1. Expression changes of several genes strongly implicated in schizophrenia pathophysiology were detected (e.g. SLC1A2, SLC1A3, SLC1A6, SLC7A11, GRIN2A, GRIA1 and DLX1).

Deletion of Rapgef6, a candidate schizophrenia susceptibility gene, disrupts amygdala function in mice

In human genetic studies of schizophrenia, we uncovered copy-number variants in RAPGEF6 and RAPGEF2 genes. To discern the effects of RAPGEF6 deletion in humans, we investigated the behavior and neural functions of a mouse lacking Rapgef6. Rapgef6 deletion resulted in impaired amygdala function measured as reduced fear conditioning and anxiolysis. Hippocampal-dependent spatial memory and prefrontal cortex-dependent working memory tasks were intact. Neural activation measured by cFOS phosphorylation demonstrated a reduction in hippocampal and amygdala activation after fear conditioning, while neural morphology assessment uncovered reduced spine density and primary dendrite number in pyramidal neurons of the CA3 hippocampal region of knockout mice. Electrophysiological analysis showed enhanced long-term potentiation at cortico-amygdala synapses. Rapgef6 deletion mice were most impaired in hippocampal and amygdalar function, brain regions implicated in schizophrenia pathophysiology. The results provide a deeper understanding of the role of the amygdala in schizophrenia and suggest that RAPGEF6 may be a novel therapeutic target in schizophrenia.

Polymorphisms of IKBKE gene are associated with major depressive disorder and panic disorder

BACKGROUND

The immune system has been increasingly implicated in the development of mood and anxiety disorders. Inhibitor of kappa light polypeptide gene enhancer in B cells, kinase epsilon (IKBKE) gene encodes IKKε protein that is involved in innate immunity, predominantly antiviral response generation. It also bears pro-inflammatory properties that could affect psychiatric outcomes. In order to investigate the possible role of IKBKE gene in major depressive disorder (MDD) and panic disorder (PD), we conducted a case-control genetic association study concerning these disorders.

METHODS

In all, 14 SNPs of IKBKE gene were genotyped in groups of 391 patients with MDD and 190 patients with PD together with respective 389 and 371 healthy control individuals. The given groups were further divided by gender for additional analyses.

RESULTS

Substantial genetic associations were revealed between IKBKE SNPs and MDD (multiple testing adjusted P < 0.05) and suggestive associations in case of PD (P(adj) > 0.05). In addition, two SNPs that were only associated with PD among males, also displayed significantly different allele frequencies compared to PD females. This may indicate a specific role of these SNPs in male PD, but caution should be applied here due to the small size of the studied PD males group.

CONCLUSIONS

The results of this study confirm our initial findings and indicate a possible role of IKBKE gene in mood and anxiety disorders.

Bioinformatics analysis of gene expression profiles of osteoarthritis

This study aimed to explore the underlying molecular mechanisms of osteoarthritis (OA) by bioinformatics analysis. Synovial tissue samples from five OA and five normal donors (ND) were used to identify the differentially expressed genes (DEGs) by paired t-test. Pathway enrichment analysis of DEGs was performed, followed by construction of a protein-protein interaction (PPI) network. A functional enrichment analysis of the modules identified from the PPI network was performed, and the module with the highest enrichment scores was selected for pathway enrichment analysis. A total of 184 DEGs, including 95 up-regulated and 89 down-regulated DEGs, were identified. Up-regulated DEGs were enriched in 6 pathways, such as MAPK signaling and Wnt signaling pathway, while down-regulated DEGs were mainly enriched in glycolysis/gluconeogenesis. In the PPI network, PTTG1 with the highest connectivity degree of 18 was significantly related to nuclear division, mitosis and the cell cycle. Genes in Module A with the highest functional enrichment scores of 9.27 were mainly enriched in the pathways of oocyte meiosis, cell cycle, ubiquitin mediated proteolysis and progesterone-mediated oocyte maturation. The MAPK signaling and Wnt signaling pathways were closely associated with OA. The DEGs, such as PTTG1, MAP2K6, PPP3CC and CSNK1E, may be the potential targets for OA diagnosis and treatment.

Common and rare variant analysis in early-onset bipolar disorder vulnerability

Bipolar disorder is one of the most common and devastating psychiatric disorders whose mechanisms remain largely unknown. Despite a strong genetic contribution demonstrated by twin and adoption studies, a polygenic background influences this multifactorial and heterogeneous psychiatric disorder. To identify susceptibility genes on a severe and more familial sub-form of the disease, we conducted a genome-wide association study focused on 211 patients of French origin with an early age at onset and 1,719 controls, and then replicated our data on a German sample of 159 patients with early-onset bipolar disorder and 998 controls. Replication study and subsequent meta-analysis revealed two genes encoding proteins involved in phosphoinositide signalling pathway (PLEKHA5 and PLCXD3). We performed additional replication studies in two datasets from the WTCCC (764 patients and 2,938 controls) and the GAIN-TGen cohorts (1,524 patients and 1,436 controls) and found nominal P-values both in the PLCXD3 and PLEKHA5 loci with the WTCCC sample. In addition, we identified in the French cohort one affected individual with a deletion at the PLCXD3 locus and another one carrying a missense variation in PLCXD3 (p.R93H), both supporting a role of the phosphatidylinositol pathway in early-onset bipolar disorder vulnerability. Although the current nominally significant findings should be interpreted with caution and need replication in independent cohorts, this study supports the strategy to combine genetic approaches to determine the molecular mechanisms underlying bipolar disorder.

Phospholipase C-β1 and schizophrenia-related behaviors

Abnormal expression patterns of phospholipase C-β1(PLC-β1) in specific brain areas of patients with schizophrenia, and its high genetic linkage to the disorder implicated a pathogenetical involvement of PLC-β1 signaling system. The schizophrenia-related behavioral phenotypes displayed in the mutant mice lacking PLC-β1 (PLC-β1 KO) suggested that PLCβ1-linked signaling pathways may be involved in the neural system whose function is disrupted in the pathogenesis of schizophrenia. In the brain, PLC-β1 is known to be linked to muscarinic acetylcholine receptors, metabotropic glutamatergic, serotonergic, and oxytocinergic systems. The objective of this review is to provide an overview of the current knowledge regarding these schizophrenia-related behaviors and discuss the probable ways in which PLC-β1signalling can be involved in the neural mechanisms for each behavior, which may help suggest future directions for research in this area.

FKBP5 genetic variation: association with selective serotonin reuptake inhibitor treatment outcomes in major depressive disorder

OBJECTIVES

FKBP51 (51 kDa immunophilin) acts as a modulator of the glucocorticoid receptor and a negative regulator of the Akt pathway. Genetic variation in FKBP5 plays a role in antidepressant response. The aim of this study was to comprehensively assess the role of genetic variation in FKBP5, identified by both Sanger and Next Generation DNA resequencing, as well as genome-wide single nucleotide polymorphisms (SNPs) associated with FKBP5 expression in the response to the selective serotonin reuptake inhibitor (SSRI) treatment of major depressive disorder.

METHODS

We identified 657 SNPs in FKBP5 by Next Generation sequencing of 96 DNA samples from white patients, and 149 SNPs were selected for the genotyping together with 235 SNPs that were trans-associated with variation in FKBP5 expression in lymphoblastoid cells. A total of 529 DNA samples from the Mayo Clinic PGRN-SSRI Pharmacogenomic trial for which genome-wide SNPs had already been obtained were genotyped for these 384 SNPs, and associations with treatment outcomes were determined. The most significant SNPs were genotyped using 96 DNA samples from white non-Hispanic patients of the NIMH-supported Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study to attempt replication, followed by functional genomic studies.

RESULTS

Genotype-phenotype association analysis indicated that rs352428 was associated with both 8-week treatment response in the Mayo study (odds ratio=0.49; P=0.003) and 6-week response in the STAR*D replication study (odds ratio=0.74; P=0.05). The electrophoresis mobility shift assay and the reporter gene assay confirmed the possible role of this SNP in transcription regulation.

CONCLUSION

This comprehensive FKBP5 sequence study provides insight into the role of common genetic polymorphisms that might influence SSRI treatment outcomes in major depressive disorder patients.

Targeted deletion of the mouse α2 nicotinic acetylcholine receptor subunit gene (Chrna2) potentiates nicotine-modulated behaviors

Baseline and nicotine-modulated behaviors were assessed in mice harboring a null mutant allele of the nicotinic acetylcholine receptor (nAChR) subunit gene α2 (Chrna2). Homozygous Chrna2(-/-) mice are viable, show expected sex and Mendelian genotype ratios, and exhibit no gross neuroanatomical abnormalities. A broad range of behavioral tests designed to assess genotype-dependent effects on anxiety (elevated plus maze and light/dark box), motor coordination (narrow bean traverse and gait), and locomotor activity revealed no significant differences between mutant mice and age-matched wild-type littermates. Furthermore, a panel of tests measuring traits, such as body position, spontaneous activity, respiration, tremors, body tone, and startle response, revealed normal responses for Chrna2-null mutant mice. However, Chrna2(-/-) mice do exhibit a mild motor or coordination phenotype (a decreased latency to fall during the accelerating rotarod test) and possess an increased sensitivity to nicotine-induced analgesia in the hotplate assay. Relative to wild-type, Chrna2(-/-) mice show potentiated nicotine self-administration and withdrawal behaviors and exhibit a sex-dependent enhancement of nicotine-facilitated cued, but not trace or contextual, fear conditioning. Overall, our results suggest that loss of the mouse nAChR α2 subunit has very limited effects on baseline behavior but does lead to the potentiation of several nicotine-modulated behaviors.

The roles of PDGF in development and during neurogenesis in the normal and diseased nervous system

The four platelet-derived growth factor (PDGF) ligands and PDGF receptors (PDGFRs), α and β (PDGFRA, PDGFRB), are essential proteins that are expressed during embryonic and mature nervous systems, i.e., in neural progenitors, neurons, astrocytes, oligodendrocytes, and vascular cells. PDGF exerts essential roles from the gastrulation period to adult neuronal maintenance by contributing to the regulation of development of preplacodal progenitors, placodal ectoderm, and neural crest cells to adult neural progenitors, in coordinating with other factors. In adulthood, PDGF plays critical roles for maintenance of many specific cell types in the nervous system together with vascular cells through controlling the blood brain barrier homeostasis. At injury or various stresses, PDGF modulates neuronal excitability through adjusting various ion channels, and affecting synaptic plasticity and function. Furthermore, PDGF stimulates survival signals, majorly PI3-K/Akt pathway but also other ways, rescuing cells from apoptosis. Studies imply an involvement of PDGF in dendrite spine morphology, being critical for memory in the developing brain. Recent studies suggest association of PDGF genes with neuropsychiatric disorders. In this review, we will describe the roles of PDGF in the nervous system, from the discovery to recent findings, in order to understand the broad spectrum of PDGF in the nervous system. Recent development of pharmacological and replacement therapies targeting the PDGF system is discussed.

Behavioural and functional characterization of Kv10.1 (Eag1) knockout mice

K_v10.1 (Eag1), member of the K_v10 family of voltage-gated potassium channels, is preferentially expressed in adult brain. The aim of the present study was to unravel the functional role of K_v10.1 in the brain by generating knockout mice, where the voltage sensor and pore region of K_v10.1 were removed to render non-functional proteins through deletion of exon 7 of the KCNH1 gene using the ‘3 Lox P strategy’. K_v10.1-deficient mice show no obvious alterations during embryogenesis and develop normally to adulthood; cortex, hippocampus and cerebellum appear anatomically normal. Other tests, including general health screen, sensorimotor functioning and gating, anxiety, social behaviour, learning and memory did not show any functional aberrations in K_v10.1 null mice. K_v10.1 null mice display mild hyperactivity and longer-lasting haloperidol-induced catalepsy, but there was no difference between genotypes in amphetamine sensitization and withdrawal, reactivity to apomorphine and haloperidol in the prepulse inhibition tests or to antidepressants in the haloperidol-induced catalepsy. Furthermore, electrical properties of K_v10.1 in cerebellar Purkinje cells did not show any difference between genotypes. Bearing in mind that K_v10.1 is overexpressed in over 70% of all human tumours and that its inhibition leads to a reduced tumour cell proliferation, the fact that deletion of K_v10.1 does not show a marked phenotype is a prerequisite for utilizing K_v10.1 blocking and/or reduction techniques, such as siRNA, to treat cancer.

The association of white matter volume in psychotic disorders with genotypic variation in NRG1, MOG and CNP: a voxel-based analysis in affected individuals and their unaffected relatives

We investigated the role of variation in putative psychosis genes coding for elements of the white matter system by examining the contribution of genotypic variation in three single-nucleotide polymorphisms (SNPs) neuregulin 1 (NRG1) SNP8NRG221533, myelin oligodendrocytes glycoprotein (MOG) rs2857766 and CNP (rs2070106) and one haplotype HAP(ICE) (deCODE) to white matter volume in patients with psychotic disorder and their unaffected relatives. Structural magnetic resonance imaging and blood samples for genotyping were collected on 189 participants including patients with schizophrenia (SZ) or bipolar I disorder (BDI), unaffected first-degree relatives of these patients and healthy volunteers. The association of genotypic variation with white matter volume was assessed using voxel-based morphometry in SPM5. The NRG1 SNP and the HAP(ICE) haplotype were associated with abnormal white matter volume in the BDI group in the fornix, cingulum and parahippocampal gyrus circuit. In SZ the NRG1 SNP risk allele was associated with lower white matter volume in the uncinate fasciculus (UF), right inferior longitudinal fasciculus and the anterior limb of the internal capsule. Healthy G-homozygotes of the MOG SNP had greater white matter volume in areas of the brainstem and cerebellum; this relationship was absent in those with a psychotic disorder and the unaffected relatives groups. The CNP SNP did not contribute to white matter volume variation in the diagnostic groups studied. Variation in the genes coding for structural and protective components of myelin are implicated in abnormal white matter volume in the emotion circuitry of the cingulum, fornix, parahippocampal gyrus and UF in psychotic disorders.

Cytokines, neurophysiology, neuropsychology, and psychiatric symptoms

Recent research has overcome the old paradigms of the brain as an immunologically privileged organ, and of the exclusive role of neurotransmitters and neuropeptides as signal transducers in the central nervous system. Growing evidence suggests that the signal proteins of the immune system - the cytokines - are also involved in modulation of behavior and induction of psychiatric symptoms. This article gives an overview on the nature of cytokines and the proposed mechanisms of immune-to-brain interaction. The role of cytokines in psychiatric symptoms, syndromes, and disorders like sickness behavior, major depression, and schizophrenia are discussed together with recent immunogenetic findings.

Linkage analysis for plasma amyloid beta levels in persons with hypertension implicates Aβ-40 levels to presenilin 2

Plasma concentrations of Aβ40 and Aβ42 rise with age and are increased in people with mutations that cause early-onset Alzheimer's disease (AD). Amyloid beta (Aβ) plasma levels were successfully used as an (endo)phenotype for gene discovery using a linkage approach in families with dominant forms of disease. Here, we searched for loci involved in Aβ plasma levels in a series of non-demented patients with hypertension in the Erasmus Rucphen Family study. Aβ40 and Aβ42 levels were determined in 125 subjects with severe hypertension. All patients were genotyped with a 6,000 single nucleotide polymorphisms (SNPs) illumina array designed for linkage analysis. We conducted linkage analysis of plasma Aβ levels. None of the linkage analyses yielded genome-wide significant logarithm of odds (LOD) score over 3.3, but there was suggestive evidence for linkage (LOD > 1.9) for two regions: 1q41 (LOD = 2.07) and 11q14.3 (LOD = 2.97), both for Aβ40. These regions were followed up with association analysis in the study subjects and in 320 subjects from a population-based cohort. For the Aβ40 region on chromosome 1, association of several SNPs was observed at the presenilin 2 gene (PSEN2) (p = 2.58 × 10(-4) for rs6703170). On chromosome 11q14-21, we found some association (p = 3.1 × 10(-3) for rs2514299). This linkage study of plasma concentrations of Aβ40 and Aβ42 yielded two suggestive regions, of which one points toward a known locus for familial AD.