Fine mapping of ZNF804A and genome-wide significant evidence for its involvement in schizophrenia and bipolar disorder

MicroRNA dysregulation in glutamate and dopamine pathways of schizophrenia: From molecular pathways to diagnostic and therapeutic approaches

Schizophrenia is a complex psychiatric disorder, and genetic and environmental factors have been implicated in its development. Dysregulated glutamatergic and dopaminergic transmission pathways are involved in schizophrenia development. Besides genetic mutations, epigenetic dysregulation has a considerable role in dysregulating molecular pathways involved in schizophrenia. MicroRNAs (miRNAs) are small, non-coding RNAs that target specific mRNAs and inhibit their translation into proteins. As epigenetic factors, miRNAs regulate many genes involved in glutamate and dopamine signaling pathways; thereby, their dysregulation can contribute to the development of schizophrenia. Secretion of specific miRNAs from damaged cells into body fluids can make them one of the ideal non-invasive biomarkers in the early diagnosis of schizophrenia. Also, understanding the molecular mechanisms of miRNAs in schizophrenia pathogenesis can pave the way for developing novel treatments for patients with schizophrenia. In this study, we reviewed the glutamatergic and dopaminergic pathophysiology and highlighted the role of miRNA dysregulation in schizophrenia development. Besides, we shed light on the significance of circulating miRNAs for schizophrenia diagnosis and the recent findings on the miRNA-based treatment for schizophrenia.

Schizophrenia-Like Deficits and Impaired Glutamate/Gamma-aminobutyric acid Homeostasis in Zfp804a Conditional Knockout Mice

BACKGROUND AND HYPOTHESIS

Zinc finger protein 804A (ZNF804A) was the first genome-wide associated susceptibility gene for schizophrenia (SCZ) and played an essential role in the pathophysiology of SCZ by influencing neurodevelopment regulation, neurite outgrowth, synaptic plasticity, and RNA translational control; however, the exact molecular mechanism remains unclear.

STUDY DESIGN

A nervous-system-specific Zfp804a (ZNF804A murine gene) conditional knockout (cKO) mouse model was generated using clustered regularly interspaced short palindromic repeat/Cas9 technology and the Cre/loxP method.

RESULTS

Multiple and complex SCZ-like behaviors, such as anxiety, depression, and impaired cognition, were observed in Zfp804a cKO mice. Molecular biological methods and targeted metabolomics assay validated that Zfp804a cKO mice displayed altered SATB2 (a cortical superficial neuron marker) expression in the cortex; aberrant NeuN, cleaved caspase 3, and DLG4 (markers of mature neurons, apoptosis, and postsynapse, respectively) expressions in the hippocampus and a loss of glutamate (Glu)/γ-aminobutyric acid (GABA) homeostasis with abnormal GAD67 (Gad1) expression in the hippocampus. Clozapine partly ameliorated some SCZ-like behaviors, reversed the disequilibrium of the Glu/GABA ratio, and recovered the expression of GAD67 in cKO mice.

CONCLUSIONS

Zfp804a cKO mice reproducing SCZ-like pathological and behavioral phenotypes were successfully developed. A novel mechanism was determined in which Zfp804a caused Glu/GABA imbalance and reduced GAD67 expression, which was partly recovered by clozapine treatment. These findings underscore the role of altered gene expression in understanding the pathogenesis of SCZ and provide a reliable SCZ model for future therapeutic interventions and biomarker discovery.

The function of Mef2c toward the development of excitatory and inhibitory cortical neurons

Neurodevelopmental disorders (NDDs) are caused by abnormal brain development, leading to altered brain function and affecting cognition, learning, self-control, memory, and emotion. NDDs are often demarcated as discrete entities for diagnosis, but empirical evidence indicates that NDDs share a great deal of overlap, including genetics, core symptoms, and biomarkers. Many NDDs also share a primary sensitive period for disease, specifically the last trimester of pregnancy in humans, which corresponds to the neonatal period in mice. This period is notable for cortical circuit assembly, suggesting that deficits in the establishment of brain connectivity are likely a leading cause of brain dysfunction across different NDDs. Regulators of gene programs that underlie neurodevelopment represent a point of convergence for NDDs. Here, we review how the transcription factor MEF2C, a risk factor for various NDDs, impacts cortical development. Cortical activity requires a precise balance of various types of excitatory and inhibitory neuron types. We use MEF2C loss-of-function as a study case to illustrate how brain dysfunction and altered behavior may derive from the dysfunction of specific cortical circuits at specific developmental times.

Schizophrenia risk proteins ZNF804A and NT5C2 interact in cortical neurons

The zinc finger protein 804A (ZNF804A) and the 5'-nucleotidase cytosolic II (NT5C2) genes are amongst the first schizophrenia susceptibility genes to have been identified in large-scale genome-wide association studies. ZNF804A has been implicated in the regulation of neuronal morphology and is required for activity-dependent changes to dendritic spines. Conversely, NT5C2 has been shown to regulate 5' adenosine monophosphate-activated protein kinase activity and has been implicated in protein synthesis in human neural progenitor cells. Schizophrenia risk genotype is associated with reduced levels of both NT5C2 and ZNF804A in the developing brain, and a yeast two-hybrid screening suggests that their encoded proteins physically interact. However, it remains unknown whether this interaction also occurs in cortical neurons and whether they could jointly regulate neuronal function. Here, we show that ZNF804A and NT5C2 colocalise and interact in HEK293T cells and that their rodent homologues, ZFP804A and NT5C2, colocalise and form a protein complex in cortical neurons. Knockdown of the Zfp804a or Nt5c2 genes resulted in a redistribution of both proteins, suggesting that both proteins influence the subcellular targeting of each other. The identified interaction between ZNF804A/ZFP804A and NT5C2 suggests a shared biological pathway pertinent to schizophrenia susceptibility within a neuronal cell type thought to be central to the neurobiology of the disorder, providing a better understanding of its genetic landscape.

Impulsivity and aggression in alcohol withdrawal syndrome is modulated by the interaction of ZNF804A and mTOR polymorphism

Alcohol withdrawal syndrome (AWS) is a poorly studied phenotype of alcohol use disorder. Understanding the relationship between allelic interactions and AWS-related impulsivity and aggression could have significant implications. This study aimed to investigate the main and interacting effects of ZNF804A and mTOR on impulsivity and aggression during alcohol withdrawal. 446 Chinese Han adult males with alcohol dependence were included in the study. Impulsivity and aggression were assessed, and genomic DNA was genotyped. Single gene analysis showed that ZNF804A rs1344706 (A allele/CC homozygote) and mTOR rs1057079 (C allele/TT homozygote) were strongly associated with AWS-related impulsivity and aggression. In the allelic group, MANOVA revealed a significant gene x gene interaction, suggesting that risk varied systematically depending on both ZNF804A and mTOR alleles. Additionally, a significant interactive effect of ZNF804A rs1344706 and mTOR rs7525957 was found on motor impulsivity and physical aggression, and the ZNF804A rs1344706 gene variant had significant effects on motor impulsivity and physical aggression only in mTOR rs7525957 TT homozygous carriers. The study showed that specific allelic combinations of ZNF804A and mTOR may have protective or risk-enhancing effects on AWS-related impulsivity and aggression.

Using brain cell-type-specific protein interactomes to interpret neurodevelopmental genetic signals in schizophrenia

Genetics have nominated many schizophrenia risk genes and identified convergent signals between schizophrenia and neurodevelopmental disorders. However, functional interpretation of the nominated genes in the relevant brain cell types is often lacking. We executed interaction proteomics for six schizophrenia risk genes that have also been implicated in neurodevelopment in human induced cortical neurons. The resulting protein network is enriched for common variant risk of schizophrenia in Europeans and East Asians, is down-regulated in layer 5/6 cortical neurons of individuals affected by schizophrenia, and can complement fine-mapping and eQTL data to prioritize additional genes in GWAS loci. A sub-network centered on HCN1 is enriched for common variant risk and contains proteins (HCN4 and AKAP11) enriched for rare protein-truncating mutations in individuals with schizophrenia and bipolar disorder. Our findings showcase brain cell-type-specific interactomes as an organizing framework to facilitate interpretation of genetic and transcriptomic data in schizophrenia and its related disorders.

Impact of ZNF804A rs1344706 or CACNA1C rs1006737 polymorphisms on cognition in patients with severe mental disorders: A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis focussed on insights into the relationship between CACNA1C-rs1006737 and ZNF804A-rs1344706 polymorphisms and cognitive performance in schizophrenia (SCZ) spectrum and bipolar disorder (BD) and provide some contributions for clinical practice.

METHODS

We searched the websites databases (PubMED, PsycINFO, Web of Science, EMBASE and Cochrane Library) using eligibility and exclusion criteria to capture all potential studies, based on PICO model and according to the PRISMA.

RESULTS

Eight articles were included in this systematic review (five referring to CACNA1C-rs1006737 and three related to ZNF804A-rs1344706 polymorphisms), with a total of 5759 participants (1751 SCZ patients, 348 BD patients, 3626 controls and 34 first-degree relatives). The results demonstrated that the pooled effect of CACNA1C-rs1006737 (risk difference RD = 0.08; 95% CI 0.02-0.15) was associated with altered cognitive function in patients with severe mental disorders, but not ZNF804A-rs1344706 polymorphism (RD = 0.19; 95% CI 0.09-0.48.

CONCLUSION

The present meta-analysis provides evidence regarding slight association between CACNA1C-rs1006737 polymorphisms and cognitive performance in severe mental disorders, indicating that cognitive impairment in severe mental disorders associated with the CACNA1C rs1006737 risk variants could only be expressed when interacting with environmental exposures. This study is registered with PROSPERO, number CRD42021246726.

Psychosis susceptibility zinc finger protein 804A (ZNF804A) gene polymorphism in schizophrenia patients treated with olanzapine in North Indian population

PURPOSE

The Zinc finger protein 804A (ZNF804A) is a potential schizophrenia candidate gene that has emerged from genome-wide association studies. The aim of the study is to investigate whether this gene variant influences the response of positive or negative symptoms to antipsychotic drug olanzapine in North Indian schizophrenia patients.

MATERIALS AND METHODS

Our study involved 184 unrelated schizophrenia cases (114 males and 70 females; mean age: 52.8 ± 11.6 years) and 300 normal controls (168 males and 132 females; mean age: 54.9 ± 6.9 years). At the start of treatment and after four weeks, we assessed the response of positive and negative symptoms by positive and negative syndrome scale (PANSS). Olanzapine drug level was estimated using HPLC Method and Genotyping was performed using PCR-Snap Shot technique.

RESULTS

Significant differences were observed in the genotype distribution (χ² = 6.10, d.f. = 2, p = 0.04) and allele frequencies (χ² = 5.14, d.f. = 1, p = 0.02; odds ratio = 0.57, 95% confidence interval =1.09-3.48) between schizophrenia patients and controls group. The improvement of positive and negative schizophrenia symptoms after 4 weeks of treatment with olanzapine was assessed. Patients homozygous for the ZNF804A risk allele for AA show poorer improvement of positive symptoms compared to patients with a protective allele.

CONCLUSIONS

Our findings indicate that ZNF804A gene polymorphism plays a significant role in the treatment of schizophrenia, suggesting that ZNF804A may be an effective marker for schizophrenia treatment.

Polymorphism in the ZNF804A Gene and Variation in D1 and D2/D3 Dopamine Receptor Availability in the Healthy Human Brain: A Dual Positron Emission Tomography Study

BACKGROUND

The rs1344706 single nucleotide polymorphism in the ZNF804A gene has been associated with risk for psychosis in multiple genome-wide association studies, yet mechanisms underlying this association are not known. Given preclinical work suggesting an impact of ZNF804A on dopamine receptor gene transcription and clinical studies establishing dopaminergic dysfunction in patients with schizophrenia, we hypothesized that the ZNF804A risk single nucleotide polymorphism would be associated with variation in dopamine receptor availability in the human brain.

METHODS

In this study, 72 healthy individuals genotyped for rs1344706 completed both [18F]fallypride and [11C]NNC-112 positron emission tomography scans to measure D2/D3 and D1 receptor availability, respectively. Genetic effects on estimates of binding potential for each ligand were tested first with canonical subject-specific striatal regions of interest analyses, followed by exploratory whole-brain voxelwise analyses to test for more localized striatal signals and for extrastriatal effects.

RESULTS

Region of interest analyses revealed significantly less D2/D3 receptor availability in risk-allele homozygotes (TT) compared with non-risk allele carriers (G-allele carrier group: TG and GG) in the associative striatum and sensorimotor striatum, but no significant differences in striatal D1 receptor availability.

CONCLUSIONS

These data suggest that ZNF804A genotype may be meaningfully linked to dopaminergic function in the human brain. The results also may provide information to guide future studies of ZNF804A-related mechanisms of schizophrenia risk.

A functional neuroimaging association study on the interplay between two schizophrenia genome-wide associated genes (CACNA1C and ZNF804A)

The CACNA1C and the ZNF804A genes are among the most relevant schizophrenia GWAS findings. Recent evidence shows that the interaction of these genes with the schizophrenia diagnosis modulates brain functional response to a verbal fluency task. To better understand how these genes might influence the risk for schizophrenia, we aimed to study the interplay between CACNA1C and ZNF804A on working memory brain functional correlates. The analyses included functional and behavioural N-back task data (obtained from an fMRI protocol) and CACNA1C-rs1006737 and ZNF804A-rs1344706 genotypes for 78 healthy subjects and 78 patients with schizophrenia (matched for age, sex and premorbid IQ). We tested the effects of the epistasis between these genes as well as of the three-way interaction (CACNA1C × ZNAF804A × diagnosis) on working memory-associated activity (N-back: 2-back vs 1-back). We detected a significant CACNA1C × ZNAF804A interaction on working memory functional response in regions comprising the ventral caudate medially and within the left hemisphere, the superior and inferior orbitofrontal gyrus, the superior temporal pole and the ventral-anterior insula. The individuals with the GWAS-identified risk genotypes (CACNA1C-AA/AG and ZNF804A-AA) displayed a reduced working memory modulation response. This genotypic combination was also associated with opposite brain activity patterns between patients and controls. While further research will help to comprehend the neurobiological mechanisms of this interaction, our data highlight the role of the epistasis between CACNA1C and ZNF804A in the functional mechanisms underlying the pathophysiology of schizophrenia.

Effects of psychosis-associated genetic markers on brain volumetry: a systematic review of replicated findings and an independent validation

BACKGROUND

Given psychotic illnesses' high heritability and associations with brain structure, numerous neuroimaging-genetics findings have been reported in the last two decades. However, few findings have been replicated. In the present independent sample we aimed to replicate any psychosis-implicated SNPs (single nucleotide polymorphisms), which had previously shown at least two main effects on brain volume.

METHODS

A systematic review for SNPs showing a replicated effect on brain volume yielded 25 studies implicating seven SNPs in five genes. Their effect was then tested in 113 subjects with either schizophrenia, bipolar disorder, 'at risk mental state' or healthy state, for whole-brain and region-of-interest (ROI) associations with grey and white matter volume changes, using voxel-based morphometry.

RESULTS

We found FWER-corrected (Family-wise error rate) (i.e. statistically significant) associations of: (1) CACNA1C-rs769087-A with larger bilateral hippocampus and thalamus white matter, across the whole brain; and (2) CACNA1C-rs769087-A with larger superior frontal gyrus, as ROI. Higher replication concordance with existing literature was found, in decreasing order, for: (1) CACNA1C-rs769087-A, with larger dorsolateral-prefrontal/superior frontal gyrus and hippocampi (both with anatomical and directional concordance); (2) ZNF804A-rs11681373-A, with smaller angular gyrus grey matter and rectus gyri white matter (both with anatomical and directional concordance); and (3) BDNF-rs6265-T with superior frontal and middle cingulate gyri volume change (with anatomical and allelic concordance).

CONCLUSIONS

Most literature findings were not herein replicated. Nevertheless, high degree/likelihood of replication was found for two genome-wide association studies- and one candidate-implicated SNPs, supporting their involvement in psychosis and brain structure.

Genetic analysis of the ZNF804A gene in Mexican patients with schizophrenia, schizoaffective disorder and bipolar disorder

BACKGROUND

Evidence suggests that schizophrenia (SCZ), schizoaffective disorder (SAD) and bipolar disorder (BPD) share genetic risk variants. ZNF804A gene has been associated with these disorders in different populations. GWAS and candidate gene studies have reported association between the rs1344706 A allele with SCZ, SAD and BPD in European and Asian populations. In Mexican patients, no studies have specifically analyzed ZNF804A gene variants with these disorders. The aim of the study was to analyze the rs1344706 and identify common and rare variants in a targeted region of the ZNF804A gene in Mexican patients with SCZ, BPD and SAD compared with a control group.

METHODS

We genotyped the rs1344706 in 228 Mexican patients diagnosed with SCZ, SAD and BPD, and 295 controls. Also, an additional sample of 167 patients with these disorders and 170 controls was analyzed to identify rare and common variants using the Sanger-sequence analysis of a targeted region of ZNF804A gene.

RESULTS

Association analysis of rs1344706 observed a higher frequency of A allele in the patients compared with the control group; however, did not show statistical differences after Bonferronís correction (χ2 = 5.3, p = 0.0208). In the sequence analysis, we did not identify rare variants; however, we identified three common variants: rs3046266, rs1366842 and rs12477430. A comparison of the three identified variants between patients and controls did not show statistical differences (p > 0.0125). Finally, haplotype analysis did not show statistical differences between SCZ, SAD and BPD and controls.

CONCLUSIONS

Our findings did not support the evidence suggesting that ZNF804A gene participates in the etiology of SCZ, SAD and BPD. Future studies are needed in a larger sample size to identify the effect of this gene in psychiatric disorders.

Schizophrenia-associated variation at ZNF804A correlates with altered experience-dependent dynamics of sleep slow waves and spindles in healthy young adults

The rs1344706 polymorphism in ZNF804A is robustly associated with schizophrenia and schizophrenia is, in turn, associated with abnormal non-rapid eye movement (NREM) sleep neurophysiology. To examine whether rs1344706 is associated with intermediate neurophysiological traits in the absence of disease, we assessed the relationship between genotype, sleep neurophysiology, and sleep-dependent memory consolidation in healthy participants. We recruited healthy adult males with no history of psychiatric disorder from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. Participants were homozygous for either the schizophrenia-associated 'A' allele (N = 22) or the alternative 'C' allele (N = 18) at rs1344706. Actigraphy, polysomnography (PSG) and a motor sequence task (MST) were used to characterize daily activity patterns, sleep neurophysiology and sleep-dependent memory consolidation. Average MST learning and sleep-dependent performance improvements were similar across genotype groups, albeit more variable in the AA group. During sleep after learning, CC participants showed increased slow-wave (SW) and spindle amplitudes, plus augmented coupling of SW activity across recording electrodes. SW and spindles in those with the AA genotype were insensitive to learning, whilst SW coherence decreased following MST training. Accordingly, NREM neurophysiology robustly predicted the degree of overnight motor memory consolidation in CC carriers, but not in AA carriers. We describe evidence that rs1344706 polymorphism in ZNF804A is associated with changes in the coordinated neural network activity that supports offline information processing during sleep in a healthy population. These findings highlight the utility of sleep neurophysiology in mapping the impacts of schizophrenia-associated common genetic variants on neural circuit oscillations and function.

Towards Understanding the Genetic Nature of Vasovagal Syncope

Syncope, defined as a transient loss of consciousness caused by transient global cerebral hypoperfusion, affects 30-40% of humans during their lifetime. Vasovagal syncope (VVS) is the most common cause of syncope, the etiology of which is still unclear. This review summarizes data on the genetics of VVS, describing the inheritance pattern of the disorder, candidate gene association studies and genome-wide studies. According to this evidence, VVS is a complex disorder, which can be caused by the interplay between genetic factors, whose contribution varies from monogenic Mendelian inheritance to polygenic inherited predisposition, and external factors affecting the monogenic (resulting in incomplete penetrance) and polygenic syncope types.

Ethnicity-dependent effects of Zinc finger 804A variant on schizophrenia: a systematic review and meta-analysis

OBJECTIVES

Previous studies and meta-analysis indicated that rs1344706 was associated with schizophrenia in European population, whereas the conclusions in other populations were disputed. To further explore whether the allele A of rs1344706 would increase the risk of schizophrenia in different populations and update the original meta-analysis, we conducted a systematic review and meta-analysis worldwide.

METHODS

A literature search was performed in PubMed, Embase, Cochrane Library, PsycINFO and Web of Science (up to 10 July 2019) according to the inclusion criteria.

RESULTS

A total of 27 articles were included. Our meta-analysis showed an association between rs1344706 and schizophrenia in total populations [P = 0.000; odds ratio (OR) = 1.105; 95% confidence interval (CI), 1.048-1.165], Europe population (P = 0.025; OR = 1.108; 95% CI, 1.013-1.222) and Asian population(P = 0.005; OR = 1.094; 95% CI, 1.027-1.164).

CONCLUSIONS

Our findings suggested that the risk of single nucleotide polymorphism rs1344706 A-allele may increase the risk of schizophrenia worldwide. Also, this ethnicity-dependent effects of ZNF804A variant on schizophrenia may be related to the opposite allele direction. But to elucidate the underlying biological mechanism, further studies with large participant populations are needed.

Schizophrenia risk candidate protein ZNF804A interacts with STAT2 and influences interferon-mediated gene transcription in mammalian cells

Previously evidence was presented that the single-nucleotide polymorphism rs1344706 located in an intronic region of the ZNF804A gene is associated with reduced transcript levels in fetal brains. This genetic variation in the gene encoding the zinc-finger protein ZNF804A is associated with schizophrenia (SZ) and bipolar disorder. Currently, the molecular and cellular function of ZNF804A is unclear. Here, we generated a high-confidence protein-protein interaction (PPI) network for ZNF804A using a combination of yeast two-hybrid and bioluminescence-based PPI detection assays, directly linking 12 proteins to the disease-associated target protein. Among the top hits was the signal transducer and activator of transcription 2 (STAT2), an interferon-regulated transcription factor. Detailed mechanistic studies revealed that STAT2 binds to the unstructured N-terminus of ZNF804A. This interaction is mediated by multiple short amino acid motifs in ZNF804A but not by the conserved C2H2 zinc-finger domain, which is also located at the N-terminus. Interestingly, investigations in HEK293 cells demonstrated that ZNF804A and STAT2 both co-translocate from the cytoplasm into the nucleus upon interferon (IFN) treatment. Furthermore, a concentration-dependent effect of ZNF804A overproduction on STAT2-mediated gene expression was observed using a luciferase reporter, which is under the control of an IFN-stimulated response element (ISRE). Together these results indicate the formation of ZNF804A:STAT2 protein complex and its translocation from the cytoplasm into the nucleus upon IFN stimulation, suggesting that it may function as a signal transducer that activates IFN-mediated gene expression programs.

Mapping working memory-specific dysfunction using a transdiagnostic approach

Background

Working memory (WM) is an executive ability that allows one to hold and manipulate information for a short period of time. Schizophrenia and mood disorders are severe psychiatric conditions with overlapping genetic and clinical symptoms. Whilst WM has been suggested as meeting the criteria for being an endophenotype for schizophrenia and mood disorders, it still unclear whether they share overlapping neural circuitry.

Objective

The n-back task has been widely used to measure WM capacity, such as maintenance, flexible updating, and interference control. Here we compiled studies that included psychiatric populations, i.e., schizophrenia, bipolar disorder and major depressive disorder.

Methods

We performed a coordinate-based meta-analysis that combined 34 BOLD-fMRI studies comparing activity associated with n-back working memory between psychiatric patients and healthy controls. We specifically focused our search using the n-back task to diminish study heterogeneity.

Results

All patient groups showed blunted activity in the striatum, anterior insula and frontal lobe. The same brain networks related to WM were compromised in schizophrenia, major depressive disorder and bipolar disorder.

Conclusion

Our findings support the suggestion of commonal functional abnormalities across schizophrenia and mood disorders related to WM.

Schizophrenia risk ZNF804A interacts with its associated proteins to modulate dendritic morphology and synaptic development

Schizophrenia (SZ) is a devastating brain disease that affects about 1% of world population. Among the top genetic associations, zinc finger protein 804A (ZNF804A) gene encodes a zinc finger protein, associated with SZ and biolar disorder (BD). Copy number variants (CNVs) of ZNF804A have been observed in patients with autism spectrum disorders (ASDs), anxiety disorder, and BD, suggesting that ZNF804A is a dosage sensitive gene for brain development. However, its molecular functions have not been fully determined. Our previous interactomic study revealed that ZNF804A interacts with multiple proteins to control protein translation and neural development. ZNF804A is localized in the cytoplasm and neurites in the human cortex and is expressed in various types of neurons, including pyramidal, dopaminergic, GABAergic, and Purkinje neurons in mouse brain. To further examine the effect of gene dosage of ZNF804A on neurite morphology, both knockdown and overexpression of ZNF804A in primary neuronal cells significantly attenuate dendritic complex and spine formation. To determine the factors mediating these phenotypes, interestingly, three binding proteins of ZNF804A, galectin 1 (LGALS1), fasciculation and elongation protein zeta 1 (FEZ1) and ribosomal protein SA (RPSA), show different effects on reversing the deficits. LGALS1 and FEZ1 stimulate neurite outgrowth at basal level but RPSA shows no effect. Intriguingly, LGALS1 but not FEZ1, reverses the neurite outgrowth deficits induced by ZNF804A knockdown. However, FEZ1 and RPSA but not LGALS1, can ameliorate ZNF804A overexpression-mediated dendritic abnormalities. Thus, our results uncover a critical post-mitotic role of ZNF804A in neurite and synaptic development relevant to neurodevelopmental pathologies.

Comprehensive Integrative Analyses Identify TIGD5 rs75547282 as a Risk Variant for Autism Spectrum Disorder

Although recent genome-wide association studies have identified risk loci that strongly associates with autism spectrum disorder (ASD), how to pinpoint the causal genes remains a challenge. We aimed to pinpoint the potential causal genes and explore the possible susceptibility and mechanism. A convergent functional genomics (CFG) method was used to prioritize the candidate genes by combining lines of evidence, including Sherlock analysis, spatio-temporal expression patterns, expression analysis, protein-protein interactions, co-expression and association with brain structure. A higher score in the CFG approach suggested that more evidence supported this gene as an ASD risk gene. We screened genes with higher CFG scores for candidate functional single nucleotide polymorphisms (SNPs). A genotyping experiment (602 ASD children and 604 healthy sex-matched children) and the dual-luciferase reporter gene assay were followed to validate the effects of SNPs. We identified three genes (MAPT, ZNF285, and TIGD5) as candidate causal genes using the CFG approach. The genotyping experiment showed that TIGD5 rs75547282 was associated with an increased risk of ASD under the dominant model (OR = 1.37, 95% CI = 1.09-1.72, P = 0.006) though the statistical power was limited (5.2%). The T allele of rs75547282 activated the expression of TIGD5 compared with the C allele in the dual-luciferase reporter assay. Our study indicates that such comprehensive integrative analyses may be an effective way to explore promising ASD susceptibility variants and needs to be further investigated in future research. Genotyping experiments should, however, be based on a larger population sample to increase statistical power. LAY SUMMARY: We set out to pinpoint the potential causal genes of ASD and explore the possible susceptibility and mechanism by combining lines of evidence from different analyses. Our results show that TIGD5 rs75547282 is associated with the risk of ASD in the Han Chinese population. In addition, a similar framework to seek promising ASD risk variants could be further investigated in future research Autism Res 2021, 14: 631-644. © 2021 International Society for Autism Research and Wiley Periodicals LLC.

ZFP804A mutant mice display sex-dependent schizophrenia-like behaviors

Genome-wide association studies uncovered the association of ZNF804A (Zinc-finger protein 804A) with schizophrenia (SZ). In vitro data have indicated that ZNF804A might exert its biological roles by regulating spine and neurite morphogenesis. However, no in vivo data are available for the role of ZNF804A in psychiatric disorders in general, SZ in particular. We generated ZFP804A mutant mice, and they showed deficits in contextual fear and spatial memory. We also observed the sensorimotor gating impairment, as revealed by the prepulse inhibition test, but only in female ZFP804A mutant mice from the age of 6 months. Notably, the PPI difference between the female mutant and control mice was no longer existed with the administration of Clozapine or after the ovariectomy. Hippocampal long-term potentiation was normal in both genders of the mutant mice. Long-term depression was absent in male mutants, but facilitated in the female mutants. Protein levels of hippocampal serotonin-6 receptor and GABAB1 receptor were increased, while those of cortical dopamine 2 receptor were decreased in the female mutants with no obvious changes in the male mutants. Moreover, the spine density was reduced in the cerebral cortex and hippocampus of the mutant mice. Knockdown of ZFP804A impaired the neurite morphogenesis of cortical and hippocampal neurons, while its overexpression enhanced neurite morphogenesis only in the cortical neurons in vitro. Our data collectively support the idea that ZFP804A/ZNF804A plays important roles in the cognitive functions and sensorimotor gating, and its dysfunction may contribute to SZ, particularly in the female patients.

Association Analysis Between Common Variants of the TRPM1 Gene and Three Mental Disorders in the Han Chinese Population

Objective: Our study was designed to determine if the TRPM1 gene is associated with any of three mental disorders. The project included a cross disorder meta-analysis and association analysis including 141701 cases and 175248 controls. Materials and Methods: We genotyped eight tag single nucleotide polymorphisms (SNPs) in 1248 unrelated schizophrenia (SCZ) patients, 1056 major depressive disorder patients, 1344 bipolar disorder patients, and 1248 normal controls. We then performed a meta-analysis of 10 GWASs to identify common genetic factors among these three mental disorders. Finally, we performed a meta-analysis of six GWASs to explore the role of rs10162727 in SCZ. Result: Although two haplotypes of the TRPM1 gene, rs1035706-rs10162727 and rs10162727-rs3784599, were identified in the control group, as well as all three disease groups, none of the eight tag SNP associations remained significant after correction for multiple tests. In this cross-disorder meta-analysis of the three diseases, none of the tag SNPs were confirmed to be common among the diseases. In addition, in the meta-analysis conducted for the rs10162727 locus in SCZ, there was no significant association (p-value = 0.84, odds ratio = 1.02 [95% CI = 0.87-1.19]). Conclusion: In the Han Chinese population, no significant evidence was found linking variants of the TRPM1 gene with any of the mental disorders examined.

MIR137 polygenic risk is associated with schizophrenia and affects functional connectivity of the dorsolateral prefrontal cortex

BACKGROUND

Genome-wide association studies (GWAS) have consistently revealed that a variant of microRNA 137 (MIR137) shows a quite significant association with schizophrenia. Identifying the network of genes regulated by MIR137 could provide insights into the biological processes underlying schizophrenia. In addition, DLPFC functional connectivity, a robust correlate of MIR137, may provide plausible endophenotypes. However, the regulatory role of the MIR137 gene network in the disrupted functional connectivity remains unclear. Here, we tested the effects of the MIR137 regulated genes on the risk for schizophrenia and DLPFC functional connectivity.

METHODS

To evaluate the additive effects of the MIR137 regulated genes (N = 1274), we calculated a MIR137 polygenic risk score (PRS) for schizophrenia and tested its association with the risk for schizophrenia in the genomic data of a Han Chinese population that included schizophrenia patients (N = 589) and normal controls (N = 575). We then investigated the association between MIR137 PRS and DLPFC functional connectivity in two independent young healthy cohorts (N = 356 and N = 314).

RESULTS

We found that the MIR137 PRS successfully captured the differences in genetic structure between the patients and controls, but the single gene MIR137 did not. We then consistently found that a higher MIR137 PRS was correlated with lower functional connectivities between the DLPFC and both the superior parietal cortex and the inferior temporal cortex in two independent cohorts.

CONCLUSION

The findings suggested that these two functional connectivities of the DLPFC could be important endophenotypes linking the MIR137-regulated genetic structure to schizophrenia.

Hyperfunctioning of the right posterior superior temporal sulcus in response to neutral facial expressions presents an endophenotype of schizophrenia

Deficits in social cognition have been proposed as a marker of schizophrenia. Growing evidence suggests especially hyperfunctioning of the right posterior superior temporal sulcus (pSTS) in response to neutral social stimuli reflecting the neural correlates of social-cognitive impairments in schizophrenia. We characterized healthy participants according to schizotypy (n = 74) and the single-nucleotide polymorphism rs1344706 in ZNF804A (n = 73), as they represent risk variants for schizophrenia from the perspectives of personality traits and genetics, respectively. A social-cognitive fMRI task was applied to investigate the association of right pSTS hyperfunctioning in response to neutral face stimuli with schizotypy and rs1344706. Higher right pSTS activation in response to neutral facial expressions was found in individuals with increased positive (trend) and disorganization symptoms, as well as in carriers of the risk allele of rs1344706. In addition, a positive association between right-left pSTS connectivity and disorganization symptoms during neutral face processing was revealed. Although these findings warrant replication, we suggest that right pSTS hyperfunctioning in response to neutral facial expressions presents an endophenotype of schizophrenia. We assume that right pSTS hyperfunctioning is a vulnerability to perceive neutral social stimuli as emotionally or intentionally salient, probably contributing to the emergence of symptoms of schizophrenia.

Advanced paternal age as a risk factor for neurodevelopmental disorders: a translational study

Advanced paternal age (APA) is a risk factor for several neurodevelopmental disorders, including autism and schizophrenia. The potential mechanisms conferring this risk are poorly understood. Here, we show that the personality traits schizotypy and neuroticism correlated with paternal age in healthy subjects (N = 677). Paternal age was further positively associated with gray matter volume (VBM, N = 342) in the right prefrontal and the right medial temporal cortex. The integrity of fiber tracts (DTI, N = 222) connecting these two areas correlated positively with paternal age. Genome-wide methylation analysis in humans showed differential methylation in APA individuals, linking APA to epigenetic mechanisms. A corresponding phenotype was obtained in our rat model. APA rats displayed social-communication deficits and emitted fewer pro-social ultrasonic vocalizations compared to controls. They further showed repetitive and stereotyped patterns of behavior, together with higher anxiety during early development. At the neurobiological level, microRNAs miR-132 and miR-134 were both differentially regulated in rats and humans depending on APA. This study demonstrates associations between APA and social behaviors across species. They might be driven by changes in the expression of microRNAs and/or epigenetic changes regulating neuronal plasticity, leading to brain morphological changes and fronto-hippocampal connectivity, a network which has been implicated in social interaction.

Schizophrenia‑associated microRNA‑148b‑3p regulates COMT and PRSS16 expression by targeting the ZNF804A gene in human neuroblastoma cells

Zinc finger protein 804A (ZNF804A) has been identified by genome-wide association studies as a robust risk gene in schizophrenia, but how ZNF804A contributes to schizophrenia and its upstream regulation remains unknown. Previous studies have indicated that microRNAs (miRs) are key factors that regulate the expression levels of their target genes. The present study revealed significantly increased expression of miR-148b-3p in the peripheral blood of patients with first-onset schizophrenia compared with healthy controls, and bioinformatics analysis predicted that the ZNF804A gene is a target of miR-148b-3p. Therefore, the present study investigated the possible upstream regulation of ZNF804A by miR-148b-3p in the human neuroblastoma SH-SY5Y cell line, and assessed the implications for schizophrenia. The results revealed significantly reversed expression levels of miR-148b-3p (P=0.0051) and ZNF804A (P=0.0218) in the peripheral blood of patients with first-onset schizophrenia compared with healthy individuals. Furthermore, it was demonstrated that miR-148b-3p directly targeted ZNF804A via binding to conserved target sites in the 3′-untranslated region of ZNF804A mRNA, where it inhibited the endogenous expression of ZNF804A at both the mRNA (P=0.048) and protein levels (P=0.013) in SH-SY5Y cells. Furthermore, miR-148b-3p was revealed to regulate the expression levels of catechol-O-methyltransferase (COMT) and serine protease 16 (PRSS16) by targeting ZNF804A in SH-SY5Y cells. Collectively, the present results indicated that there was a direct upstream regulation of the schizophrenia risk gene ZNF804A by miR-148b-3p, which contributed to the regulation of the downstream genes COMT and PRSS16. Thus, the miR-148b-3p/ZNF804A/COMT/PRSS16 pathway may play an important role in the pathophysiology of schizophrenia, and may serve as a potential target in drug discovery and gene therapy for this disorder.

ZNF804A Gene Variants Have a Cross-diagnostic Influence on Psychosis and Treatment Improvement in Mood Disorders

Objective

Genetic variations in the gene encoding zinc finger protein 804A gene (ZNF804A) have been associated with major depression and bipolar disorder. In this work we focused on the potential influence of ZNF804A variations on the risk of developing specific sub-phenotypes as well as the individual response to available treatments.

Methods

We used two samples of different ethnic origin: a Korean sample, composed by 242 patients diagnosed with major depression and 132 patients diagnosed with bipolar disorder and 326 healthy controls; an Italian sample composed 151 major depression subjects, 189 bipolar disorder subjects and 38 outpatients diagnosed for a primary anxiety disorder.

Results

Our analyses reported an association of rs1344706 with psychotic phenotype in the cross-diagnostic pooled sample (geno p = 4.15 × 10⁻⁴, allelic p = 1.06 × 10⁻⁴). In the cross-diagnosis Italian sample but not in the Korean one, rs7597593 was involved with depressive symptoms improvement after treatment (geno p = 0.025, allelic p = 0.007).

Conclusion

The present study evidenced the role of ZNF804A alterations in symptoms improvement after treatment. Both manic and depressive symptoms seem to be modulated by ZNF804A, though the latter was observed in the bipolar pooled sample only. The role of this factor is likely related to synaptic development and maintenance; however, further analyses will be needed to better understand the molecular mechanics involved with ZNF804A.

Two Thalamic Regions Screened Using Laser Capture Microdissection with Whole Human Genome Microarray in Schizophrenia Postmortem Samples

We used whole human genome microarray screening of highly enriched neuronal populations from two thalamic regions in postmortem samples from subjects with schizophrenia and controls to identify brain region-specific gene expression changes and possible transcriptional targets. The thalamic anterior nucleus is reciprocally connected to anterior cingulate, a schizophrenia-affected cortical region, and is also thought to be schizophrenia affected; the other thalamic region is not. Using two regions in the same subject to identify disease-relevant gene expression differences was novel and reduced intersubject heterogeneity of findings. We found gene expression differences related to miRNA-137 and other SZ-associated microRNAs, ELAVL1, BDNF, DISC-1, MECP2 and YWHAG associated findings, synapses, and receptors. Manual curation of our data may support transcription repression.

Allelic variants in the zinc transporter-3 gene, SLC30A3, a candidate gene identified from gene expression studies, show gender-specific association with schizophrenia

Previous microarray analysis of gene expression in frontal cortex showed differential expression of genes associated with synaptic function in schizophrenia compared to matched-controls in two independent cohorts. One of these genes validated in both cohorts, SLC30A3, which encodes the Zinc Transporter 3 (ZNT3), is localised to synaptic vesicles in glutamate synapses and known to be involved in cognitive function. In view of the robust depletion of SLC30A3 mRNA in two independent studies and the importance of this gene in cognitive function, we investigated whether single nucleotide polymorphism (SNP) associations with schizophrenia could be detected in a UK case controlled schizophrenia cohort. Four SNPs were selected across this gene and genotyped in a cohort of cases and controls from East UK. We found significant associations with schizophrenia at the allelic (ORs: 1.51 to 1.57), genotype (ORs: 1.46 to 1.53) and haplotype level (P = 2.15 × 10−4). These associations proved to be gender-specific with significant effects of allele (ORs: 1.74 to 2.11), genotype (ORs: 1.78 to 2.14) and haplotype (P = 3.51 × 10−5) observed in female schizophrenia cases but not males, when split by gender. In conclusion, SNPs in SLC30A3 showed a gender-specific association with schizophrenia in this East UK cohort, which merits further investigation in other population samples.

Proof-of-concept study of a multi-gene risk score in adolescent bipolar disorder

BACKGROUND

Few studies have examined multiple genetic variants concurrently for the purpose of classifying bipolar disorder (BD); the literature among youth is particularly sparse. We selected 35 genetic variants, previously implicated in BD or associated characteristics, from which to identify the most robustly predictive group of genes.

METHODS

215 Caucasian adolescents (114 BD and 101 healthy controls (HC), ages 13-20 years) were included. Psychiatric diagnoses were determined based on semi-structured diagnostic interviews. Genomic DNA was extracted from saliva for genotyping. Two models were used to calculate a multi-gene risk score (MGRS). Model 1 used forward and backward regressions, and model 2 used a PLINK generated method.

RESULTS

In model 1, GPX3 rs3792797 was significant in the forward regression, DRD4 exonIII was significant in the backward regression; IL1β rs16944 and DISC1 rs821577 were significant in both the forward and backward regressions. These variants are involved in dopamine neurotransmission; inflammation and oxidative stress; and neuronal development. Model 1 MGRS did not significantly discriminate between BD and HC. In model 2, ZNF804A rs1344706 was significantly associated with BD; however, this association did not predict diagnosis when entered into the weighted model.

LIMITATIONS

This study was limited by the number of genetic variants examined and the modest sample size.

CONCLUSIONS

Whereas regression approaches identified four genetic variants that significantly discriminated between BD and HC, those same variants no longer discriminated between BD and HC when computed as a MGRS. Future larger studies are needed evaluating intermediate phenotypes such as neuroimaging and blood-based biomarkers.

Convergent Evidence That ZNF804A Is a Regulator of Pre-messenger RNA Processing and Gene Expression

Genome-wide association studies have linked common variation in ZNF804A with an increased risk of schizophrenia. However, little is known about the biology of ZNF804A and its role in schizophrenia. Here, we investigate the function of ZNF804A using a variety of complementary molecular techniques. We show that ZNF804A is a nuclear protein that interacts with neuronal RNA splicing factors and RNA-binding proteins including RBFOX1, which is also associated with schizophrenia, CELF3/4, components of the ubiquitin-proteasome system and the ZNF804A paralog, GPATCH8. GPATCH8 also interacts with splicing factors and is localized to nuclear speckles indicative of a role in pre-messenger RNA (mRNA) processing. Sequence analysis showed that GPATCH8 contains ultraconserved, alternatively spliced poison exons that are also regulated by RBFOX proteins. ZNF804A knockdown in SH-SY5Y cells resulted in robust changes in gene expression and pre-mRNA splicing converging on pathways associated with nervous system development, synaptic contact, and cell adhesion. We observed enrichment (P = 1.66 × 10-9) for differentially spliced genes in ZNF804A-depleted cells among genes that contain RBFOX-dependent alternatively spliced exons. Differentially spliced genes in ZNF804A-depleted cells were also enriched for genes harboring de novo loss of function mutations in autism spectrum disorder (P = 6.25 × 10-7, enrichment 2.16) and common variant alleles associated with schizophrenia (P = .014), bipolar disorder and schizophrenia (P = .003), and autism spectrum disorder (P = .005). These data suggest that ZNF804A and its paralogs may interact with neuronal-splicing factors and RNA-binding proteins to regulate the expression of a subset of synaptic and neurodevelopmental genes.

Abnormal neural functions associated with motor inhibition deficits in schizophrenia and bipolar disorder

Deficits in response inhibition have been observed in schizophrenia and bipolar disorder; however, the neural origins of the abnormalities and their relevance to genetic liability for psychosis are unknown. We used a stop‐signal task to examine motor inhibition and associated neural processes in schizophrenia patients (n = 57), bipolar disorder patients (n = 21), first‐degree biological relatives of patients with schizophrenia (n = 34), and healthy controls (n = 56). Schizophrenia patients demonstrated motor control deficits reflected in longer stop‐signal reaction times and elongated reaction times. With the possibility of needing to inhibit a button press, both schizophrenia and bipolar disorder patients showed diminished reductions of the P300 brain response and only the healthy controls demonstrated adjustments in response execution time, as measured by response‐locked lateralized readiness potentials. Schizotypal traits in the biological relatives were associated with less P300 modulation consistent with the motor‐related anomalies being associated with subtle schizophrenia‐spectrum symptomatology in family members. The two patient groups had elongated response selection processes as manifest in the delayed onset of the stimulus‐locked lateralized readiness potential. The bipolar disorder group was unique in showing significantly diminished neural responses to the stop‐signal to inhibit a response. Antipsychotic medication dosage was related to worse motor inhibition, thus motor inhibition deficits in schizophrenia may be partially explained by the effect of pharmacological agents. Failed modulation of brain processes in relation to response inhibition probability and the lengthening of motor response selection appear to be transdiagnostic abnormalities spanning schizophrenia and bipolar disorder.

Deep Convolutional Neural Network Model for Automated Diagnosis of Schizophrenia Using EEG Signals

A computerized detection system for the diagnosis of Schizophrenia (SZ) using a convolutional neural system is described in this study. Schizophrenia is an anomaly in the brain characterized by behavioral symptoms such as hallucinations and disorganized speech. Electroencephalograms (EEG) indicate brain disorders and are prominently used to study brain diseases. We collected EEG signals from 14 healthy subjects and 14 SZ patients and developed an eleven-layered convolutional neural network (CNN) model to analyze the signals. Conventional machine learning techniques are often laborious and subject to intra-observer variability. Deep learning algorithms that have the ability to automatically extract significant features and classify them are thus employed in this study. Features are extracted automatically at the convolution stage, with the most significant features extracted at the max-pooling stage, and the fully connected layer is utilized to classify the signals. The proposed model generated classification accuracies of 98.07% and 81.26% for non-subject based testing and subject based testing, respectively. The developed model can likely aid clinicians as a diagnostic tool to detect early stages of SZ.

Unravelling the genetic basis of schizophrenia and bipolar disorder with GWAS: A systematic review

OBJECTIVES

To systematically review findings of GWAS in schizophrenia (SZ) and in bipolar disorder (BD); and to interpret findings, with a focus on identifying independent replications.

METHOD

PubMed search, selection and review of all independent GWAS in SZ or BD, published since March 2011, i.e. studies using non-overlapping samples within each article, between articles, and with those of the previous review (Li et al., 2012).

RESULTS

From the 22 GWAS included in this review, the genetic associations surviving standard GWAS-significance were for genetic markers in the regions of ACSL3/KCNE4, ADCY2, AMBRA1, ANK3, BRP44, DTL, FBLN1, HHAT, INTS7, LOC392301, LOC645434/NMBR, LOC729457, LRRFIP1, LSM1, MDM1, MHC, MIR2113/POU3F2, NDST3, NKAPL, ODZ4, PGBD1, RENBP, TRANK1, TSPAN18, TWIST2, UGT1A1/HJURP, WHSC1L1/FGFR1 and ZKSCAN4. All genes implicated across both reviews are discussed in terms of their function and implication in neuropsychiatry.

CONCLUSION

Taking all GWAS to date into account, AMBRA1, ANK3, ARNTL, CDH13, EFHD1 (albeit with different alleles), MHC, PLXNA2 and UGT1A1 have been implicated in either disorder in at least two reportedly non-overlapping samples. Additionally, evidence for a SZ/BD common genetic basis is most strongly supported by the implication of ANK3, NDST3, and PLXNA2.

Associations of schizophrenia risk genes ZNF804A and CACNA1C with schizotypy and modulation of attention in healthy subjects

Schizotypy is a multidimensional risk phenotype distributed in the general population, constituting of subclinical, psychotic-like symptoms. It is associated with psychosis proneness, and several risk genes for psychosis are associated with schizotypy in non-clinical populations. Schizotypy might also modulate cognitive abilities as it is associated with attentional deficits in healthy subjects. In this study, we tested the hypothesis that established genetic risk variants ZNF804A rs1344706 and CACNA1C rs1006737 are associated with psychometric schizotypy and that schizotypy mediates their effect on attention or vice versa. In 615 healthy subjects from the FOR2107 cohort study, we analysed the genetic risk variants ZNF804A rs1344706 and CACNA1C rs1006737, psychometric schizotypy (schizotypal personality questionnaire-brief SPQB), and a neuropsychological measure of sustained and selective attention (d2 test). ZNF804A rs1344706 C (non-risk) alleles were significantly associated with higher SPQ-B Cognitive-Perceptual subscores in women and with attention deficits in both sexes. This schizotypy dimension also mediated the effect of ZNF804A on attention in women, but not in men. CACNA1C rs1006737-A showed a significant sex-modulated negative association with Interpersonal schizotypy only in men, and no effect on attention. Our multivariate model demonstrates differential genetic contributions of two psychosis risk genes to dimensions of schizotypy and, partly, to attention. This supports a model of shared genetic influence between schizotypy and cognitive functions impaired in schizophrenia.

Family-based association study of ZNF804A polymorphisms and autism in a Han Chinese population

BACKGROUND

Autism is a complex neurodevelopmental disorder with high heritability. Zinc finger protein 804A (ZNF804A) was suggested to play important roles in neurodevelopment. Previous studies indicated that single-nucleotide polymorphism (SNP) rs1344706 in ZNF804A was strongly associated with schizophrenia and might influence social interaction. Only one study explored the significance of ZNF804A polymorphisms in autism, which discovered that rs7603001 was nominally associated with autism. Moreover, no previous study investigated the association between ZNF804A and autism in a Han Chinese population. Here, we investigated whether these two SNPs (rs1344706 and rs7603001) in ZNF804A contribute to the risk of autism in a Han Chinese population.

METHODS

We performed a family-based association study in 640 Han Chinese autism trios. Sanger sequencing was used for sample genotyping. Then, single marker association analyses were conducted using the family-based association test (FBAT) program.

RESULTS

No significant association was found between the two SNPs (rs1344706 and rs7603001) in ZNF804A and autism (P > 0.05).

CONCLUSIONS

Our findings suggested that rs1344706 and rs7603001 in ZNF804A might not be associated with autism in a Han Chinese population.

Spontaneous Regional Brain Activity in Healthy Individuals is Nonlinearly Modulated by the Interaction of ZNF804A rs1344706 and COMT rs4680 Polymorphisms

ZNF804A rs1344706 has been identified as one of the risk genes for schizophrenia. However, the neural mechanisms underlying this association are unknown. Given that ZNF804A upregulates the expression of COMT, we hypothesized that ZNF804A may influence brain activity by interacting with COMT. Here, we genotyped ZNF804A rs1344706 and COMT rs4680 in 218 healthy Chinese participants. Amplitudes of low-frequency fluctuations (ALFFs) were applied to analyze the main and interaction effects of ZNF804A rs1344706 and COMT rs4680. The ALFFs of the bilateral dorsolateral prefrontal cortex showed a significant ZNF804A rs1344706 × COMT rs4680 interaction, manifesting as a U-shaped modulation, presumably by dopamine signaling. Significant main effects were also found. These findings suggest that ZNF804A affects the resting-state functional activation by interacting with COMT, and may improve our understanding of the neurobiological effects of ZNF804A and its association with schizophrenia.

The interaction between the ZNF804A gene and cannabis use on the risk of psychosis in a non-clinical sample

The ZNF804A gene and cannabis use are risk factors for psychosis and both have also been associated with schizotypal traits. This study aimed to investigate: i) the association of lifetime cannabis use (and its dose effect) with schizotypal personality traits, and ii) whether the genetic variability at ZNF804A gene modulates that association. Our sample consisted of 385 Spanish non-clinical subjects (43.1% males, mean age = 21.11(2.19)). Schizotypy was evaluated using the three factors of the Schizotypal Personality Questionnaire-Brief (SPQ-B): Cognitive-Perceptual (SPQ-CP), Interpersonal (SPQ-I) and Disorganized (SPQ-D). Subjects were classified according to their frequency of cannabis consumption, and dichotomized as users or non-users. The effects of a genetic variant of ZNF804A (rs1344706) and cannabis use, as well as their interaction, on each of the three SPQ-B factors were assessed using linear models and permutation tests. Sex, SCL anxiety scores and use of other drugs were included as covariates. Our analysis showed a significant relationship between ZNF804A and SPQ-I: AA genotype was associated with higher scores (β = 0.885 p_FDR = .018). An interaction between the AA genotype and lifetime cannabis use was found in SPQ-CP (β = 1.297 p_FDR = 0.018). This interaction showed a dose-effect pattern among AA subjects: schizotypy scores increased with increasing frequency of cannabis use (sporadic users: β = 0.746 p_FDR = 0.208; monthly users: β = 1.688 p_FDR = 0.091; intense users: β = 1.623 p_FDR = 0.038). These results add evidence on that the ZNF804A gene is associated with schizotypy and suggest that the interaction between cannabis use and ZNF804A genotype could modulate psychosis proneness.

A promoter variant in ZNF804A decreasing its expression increases the risk of autism spectrum disorder in the Han Chinese population

Synaptic pathology may be one of the cellular substrates underlying autism spectrum disorder (ASD). ZNF804A is a transcription factor that can affect or regulate the expression of many candidate genes involved in ASD. It also localizes at synapses and regulates neuronal and synaptic morphology. So far, few reports have addressed possible associations between ZNF804A polymorphisms and ASD. This study aimed to investigate whether ZNF804A genetic variants contribute to ASD susceptibility and its possible pathological role in the disorder. We analyzed the relationship of two polymorphisms (rs10497655 and rs34714481) in ZNF804A promoter region with ASD in 854 cases versus 926 controls. The functional analyses of rs10497655 were then performed using real-time quantitative polymerase chain reaction, electrophoretic mobility shift assays, chromatin immunoprecipitation and dual-luciferase assays. The variant rs10497655 was significantly associated with ASD (P = 0.007851), which had a significant effect on ZNF804A expression, with the T risk allele homozygotes related with reduced ZNF804A expression in human fetal brains. HSF2 acted as a suppressor by down-regulating ZNF804A expression and had a stronger binding affinity for the T allele of rs10497655 than for the C allele. This was the first experiment to elucidate the process in which a disease-associated SNP affects the level of ZNF804A expression by binding with the upstream regulation factor HSF2. This result indicates that the rs10497655 allelic expression difference of ZNF804A during the critical period of brain development may have an effect on postnatal phenotypes of ASD. It reveals new roles of ZNF804A polymorphisms in the pathogenesis of psychiatric disorders.

GWAS of Behavioral Traits

Over the past decade, genome-wide association studies (GWAS) have evolved into a powerful tool to investigate genetic risk factors for human diseases via a hypothesis-free scan of the genome. The success of GWAS for psychiatric disorders and behavioral traits have been somewhat mixed, partly owing to the complexity and heterogeneity of these traits. Significant progress has been made in the last few years in the development and implementation of complex statistical methods and algorithms incorporating GWAS. Such advanced statistical methods applied to GWAS hits in combination with incorporation of different layers of genomics data have catapulted the search for novel genes for behavioral traits and improved our understanding of the complex polygenic architecture of these traits.This chapter will give a brief overview on GWAS and statistical methods currently used in GWAS. The chapter will focus on reviewing the current literature and highlight some of the most important GWAS on psychiatric and other behavioral traits and will conclude with a discussion on future directions.

Imaging Genetics Towards a Refined Diagnosis of Schizophrenia

Current diagnoses of schizophrenia and related psychiatric disorders are classified by phenomenological principles and clinical descriptions while ruling out other symptoms and conditions. Specific biomarkers are needed to assist the current diagnostic system. However, complicated gene and environment interactions induce great disease heterogeneity. This unclear etiology and heterogeneity raise difficulties in distinguishing schizophrenia-related effects. Simultaneously, the overlap in symptoms, genetic variations, and brain alterations in schizophrenia and related psychiatric disorders raises similar difficulties in determining disease-specific effects. Imaging genetics is a unique methodology to assess the impact of genetic factors on both brain structure and function. More importantly, imaging genetics builds a bridge to understand the behavioral and clinical implications of genetics and neuroimaging. By characterizing and quantifying the brain measures affected in psychiatric disorders, imaging genetics is contributing to identifying potential biomarkers for schizophrenia and related disorders. To date, candidate gene analysis, genome-wide association studies, polygenetic risk score analysis, and large-scale collaborative studies have made contributions to the understanding of schizophrenia with the potential to serve as biomarkers. Despite limitations, imaging genetics remains promising as more aggregative, clustering methods and imaging genetics-compatible clinical assessments are employed in future studies. We review imaging genetics' contribution to our understanding of the heterogeneity within schizophrenia and the commonalities across schizophrenia and other diagnostic borders, and we will discuss whether imaging genetics is ready to form its own diagnostic system.

Dopamine perturbation of gene co-expression networks reveals differential response in schizophrenia for translational machinery

The dopaminergic hypothesis of schizophrenia (SZ) postulates that positive symptoms of SZ, in particular psychosis, are due to disturbed neurotransmission via the dopamine (DA) receptor D2 (DRD2). However, DA is a reactive molecule that yields various oxidative species, and thus has important non-receptor-mediated effects, with empirical evidence of cellular toxicity and neurodegeneration. Here we examine non-receptor-mediated effects of DA on gene co-expression networks and its potential role in SZ pathology. Transcriptomic profiles were measured by RNA-seq in B-cell transformed lymphoblastoid cell lines from 514 SZ cases and 690 controls, both before and after exposure to DA ex vivo (100 μM). Gene co-expression modules were identified using Weighted Gene Co-expression Network Analysis for both baseline and DA-stimulated conditions, with each module characterized for biological function and tested for association with SZ status and SNPs from a genome-wide panel. We identified seven co-expression modules under baseline, of which six were preserved in DA-stimulated data. One module shows significantly increased association with SZ after DA perturbation (baseline: P = 0.023; DA-stimulated: P = 7.8 × 10^-5; ΔAIC = -10.5) and is highly enriched for genes related to ribosomal proteins and translation (FDR = 4 × 10^-141), mitochondrial oxidative phosphorylation, and neurodegeneration. SNP association testing revealed tentative QTLs underlying module co-expression, notably at FASTKD2 (top P = 2.8 × 10^-6), a gene involved in mitochondrial translation. These results substantiate the role of translational machinery in SZ pathogenesis, providing insights into a possible dopaminergic mechanism disrupting mitochondrial function, and demonstrates the utility of disease-relevant functional perturbation in the study of complex genetic etiologies.

Convergent analysis of genome-wide genotyping and transcriptomic data suggests association of zinc finger genes with lithium response in bipolar disorder

Lithium is the mainstay treatment in bipolar disorder (BD) for its effectiveness in the acute phases of illness and in prevention of recurrences. Lithium's mechanism of action is complex, and while it modulates the function of hundreds of molecular targets, most of these effects could be unspecific and not relevant for its clinical efficacy. In this study, we applied an integrated analytical approach using genome-wide expression and genotyping data from BD patients to identify lithium-responsive genes that may serve as biomarkers of its efficacy. To this purpose, we tested the effect of treatment with lithium chloride 1 mM on the transcriptome of lymphoblasts from 10 lithium responders (LR) and 10 nonresponders (NR) patients and identified genes significantly influenced by the treatment exclusively in LR. These findings were integrated with gene-based analysis on genome-wide genotyping data from an extended sample of 205 BD patients characterized for lithium response. The expression of 29 genes was significantly changed by lithium exclusively in LR. Gene-based analysis showed that two of these genes, zinc finger protein 429 (ZNF429) and zinc finger protein 493 (ZNF493), were also significantly associated with lithium response. Validation with quantitative real-time polymerase chain reaction confirmed the lithium-induced downregulation of ZNF493 in LR (p = .036). Using convergent analyses of genome-wide expression and genotyping data, we identified ZNF493 as a potential lithium-responsive target that may be involved in modulating lithium efficacy in BD. To our knowledge, this is the first evidence supporting the involvement of zinc finger proteins in lithium response.

Control of CNS functions by RNA-binding proteins in neurological diseases

Purpose of Review

This review summarizes recent studies on the molecular mechanisms of RNA binding proteins (RBPs) that control neurological functions and pathogenesis in various neurodevelopmental and neurodegenerative diseases, including autism spectrum disorders, schizophrenia, Alzheimer's disease, amyotrophic lateral sclerosis, frontotemporal dementia, and spinocerebellar ataxia.

Recent Findings

RBPs are critical players in gene expression that regulate every step of posttranscriptional modifications. Recent genome-wide approaches revealed that many proteins associate with RNA, but do not contain any known RNA binding motifs. Additionally, many causal and risk genes of neurodevelopmental and neurodegenerative diseases are RBPs. Development of high-throughput sequencing methods has mapped out the fingerprints of RBPs on transcripts and provides unprecedented potential to discover new mechanisms of neurological diseases. Insights into how RBPs modulate neural development are important for designing effective therapies for numerous neurodevelopmental and neurodegenerative diseases.

Summary

RBPs have diverse mechanisms for modulating RNA processing and, thereby, controlling neurogenesis. Understanding the role of disease-associated RBPs in neurogenesis is vital for developing novel treatments for neurological diseases.

Interactome analysis reveals ZNF804A, a schizophrenia risk gene, as a novel component of protein translational machinery critical for embryonic neurodevelopment

Recent genome-wide association studies identified over 100 genetic loci that significantly associate with schizophrenia (SZ). A top candidate gene, ZNF804A, was robustly replicated in different populations. However, its neural functions are largely unknown. Here we show in mouse that ZFP804A, the homolog of ZNF804A, is required for normal progenitor proliferation and neuronal migration. Using a yeast two-hybrid genome-wide screen, we identified novel interacting proteins of ZNF804A. Rather than transcriptional factors, genes involved in mRNA translation are highly represented in our interactome result. ZNF804A co-fractionates with translational machinery and modulates the translational efficiency as well as the mTOR pathway. The ribosomal protein RPSA interacts with ZNF804A and rescues the migration and translational defects caused by ZNF804A knockdown. RNA immunoprecipitation-RNAseq (RIP-Seq) identified transcripts bound to ZFP804A. Consistently, ZFP804A associates with many short transcripts involved in translational and mitochondrial regulation. Moreover, among the transcripts associated with ZFP804A, a SZ risk gene, neurogranin (NRGN), is one of ZFP804A targets. Interestingly, downregulation of ZFP804A decreases NRGN expression and overexpression of NRGN can ameliorate ZFP804A-mediated migration defect. To verify the downstream targets of ZNF804A, a Duolink in situ interaction assay confirmed genes from our RIP-Seq data as the ZNF804A targets. Thus, our work uncovered a novel mechanistic link of a SZ risk gene to neurodevelopment and translational control. The interactome-driven approach here is an effective way for translating genome-wide association findings into novel biological insights of human diseases.

Association analysis of ANK3 gene variants with schizophrenia in a northern Chinese Han population

Schizophrenia is a chronic, severely debilitating mental disorder. Many studies have suggested that genetic factors play an important role in the onset and development of schizophrenia. In our study, we conducted a case-control study in a northern Chinese Han population of 499 schizophrenia patients and 500 controls to investigate the effect of variant genotypes of 13 SNPs in ANK3 on schizophrenia risk. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using the chi-squared test, genetic model analysis, and haplotype analysis. Four ANK3 SNPs were associated with schizophrenia risk. The minor allele of rs958852 in ANK3 was associated with a 0.75-fold reduction in schizophrenia risk in an allelic model. In the genetic model, rs958852 was associated with a reduced schizophrenia risk, and rs10994336, rs10994338 and rs4948418 were associated with an increased schizophrenia risk (rs10994336, OR = 2.00, 95%CI: 1.01–3.94, p = 0.047; rs10994338, OR = 1.99, 95%CI: 1.01–3.93, p = 0.047; rs4948418, OR = 2.00, 95%CI: 1.01–3.94, p = 0.047). In addition, haplotype “TTC” of ANK3 was associated with a 0.73-fold reduced schizophrenia risk (95%CI: 0.54–0.99; p = 0.044). To our knowledge, this is the first to report of an association between ANK3 rs10994336, rs10994338, rs4948418 and rs958852 and schizophrenia risk in a northern Chinese Han population.

Methods and Tools in Genome-wide Association Studies

Many traits, such as height, the response to a given drug, or the susceptibility to certain diseases are presumably co-determined by genetics. Especially in the field of medicine, it is of major interest to identify genetic aberrations that alter an individual's risk to develop a certain phenotypic trait. Addressing this question requires the availability of comprehensive, high-quality genetic datasets. The technological advancements and the decreasing cost of genotyping in the last decade led to an increase in such datasets. Parallel to and in line with this technological progress, an analysis framework under the name of genome-wide association studies was developed to properly collect and analyze these data. Genome-wide association studies aim at finding statistical dependencies-or associations-between a trait of interest and point-mutations in the DNA. The statistical models used to detect such associations are diverse, spanning the whole range from the frequentist to the Bayesian setting.Since genetic datasets are inherently high-dimensional, the search for associations poses not only a statistical but also a computational challenge. As a result, a variety of toolboxes and software packages have been developed, each implementing different statistical methods while using various optimizations and mathematical techniques to enhance the computations.This chapter is devoted to the discussion of widely used methods and tools in genome-wide association studies. We present the different statistical models and the assumptions on which they are based, explain peculiarities of the data that have to be accounted for and, most importantly, introduce commonly used tools and software packages for the different tasks in a genome-wide association study, complemented with examples for their application.

The schizophrenia susceptibility gene ZNF804A confers risk of major mood disorders

OBJECTIVES

Genome-wide association studies (GWAS) followed by independent replications suggest that ZNF804A is a risk gene for schizophrenia (SCZ), considering the substantial genetic overlap between SCZ and major mood disorders (e.g., bipolar disorder (BPD) and major depressive disorder (MDD)).

METHODS

We collected the data of two ZNF804A single-nucleotide polymorphisms (SNPs rs1344706 and rs7597593) from European and Asian populations to perform systematic meta-analyses with major mood disorders in a total of 65,240 subjects.

RESULTS

Meta-analysis showed that rs1344706 and rs7597593 were both associated with major mood disorders as well as diagnosis of either BPD or MDD, although neither of the analyses achieved a genome-wide level of statistical significance.

CONCLUSIONS

Our data provide evidence for the genetic involvement of ZNF804A SNPs in the susceptibility of major mood disorders, but further replication analyses in larger samples are necessary.