The wnt pathway in mood disorders

The Wnt signaling pathway in major depressive disorder: A systematic review of human studies

Despite uncertainty about the specific molecular mechanisms driving major depressive disorder (MDD), the Wnt signaling pathway stands out as a potentially influential factor in the pathogenesis of MDD. Known for its role in intercellular communication, cell proliferation, and fate, Wnt signaling has been implicated in diverse biological phenomena associated with MDD, spanning neurodevelopmental to neurodegenerative processes. In this systematic review, we summarize the functional differences in protein and gene expression of the Wnt signaling pathway, and targeted genetic association studies, to provide an integrated synthesis of available human data examining Wnt signaling in MDD. Thirty-three studies evaluating protein expression (n = 15), gene expression (n = 9), or genetic associations (n = 9) were included. Only fifteen demonstrated a consistently low overall risk of bias in selection, comparability, and exposure. We found conflicting observations of limited and distinct Wnt signaling components across diverse tissue sources. These data do not demonstrate involvement of Wnt signaling dysregulation in MDD. Given the well-established role of Wnt signaling in antidepressant response, we propose that a more targeted and functional assessment of Wnt signaling is needed to understand its role in depression pathophysiology. Future studies should include more components, assess multiple tissues concurrently, and follow a standardized approach.

CRISPR/Cas9 based gene editing of Frizzled class receptor 6 (FZD6) reveals its role in depressive symptoms through disrupting Wnt/β-catenin signaling pathway

INTRODUCTION

As one of the common psychiatric diseases, depression poses serious threats to human health. Although many genes have been nominated for depression, few of them were investigated in details at the molecular level.

OBJECTIVES

To demonstrate Frizzled class receptor 6 (FZD6) functions in depression through disrupting Wnt/β-catenin signal pathway.

METHODS

The FZD6 edited cell line and mouse model were generated by using CRISPR/Cas9 technique. The expression of key genes and proteins in Wnt/β-catenin pathway was determined by qRT-PCR and Western blotting, respectively. Animal behavioral tests, including open field test (OFT), elevated plus maze test (EPM), forced swimming test (FST), tail suspension test (TST), and sucrose preference test (SPT), were employed to determine anxiety- and depressive-like behaviors. Immunofluorescent staining was used to assess cell proliferation in the hippocampus of mouse brain.

RESULTS

Among patients with depression, FZD6, one of the receptors of Wnt ligand, was significantly decreased. In CRISPR/Cas9-based FZD6 knockdown cells, we showed that FZD6 plays a significant role in regulating expression of genes involved in Wnt/β-catenin pathway. Subsequently behavioral studies on Fzd6 knockdown mice (with a 5-nucleotide deletion; Fzd6-Δ5) revealed significant changes in depressive symptoms, including increased immobility duration in FST, less preference of sucrose in SPT, reduction of distance traveled in OFT, and decreased time spent in open arms in EPM. Immunofluorescent staining showed decreased cell proliferation in the hippocampus of Fzd6-Δ5 mice with reduced number of Ki67+ and PCNA+ cells. Moreover, decreased Gsk3β mRNA expression, phosphorylated GSK3β, and cytoplasmic β-catenin in the hippocampus of Fzd6-Δ5 mice provided further evidence supporting the role of Fzd6 in depression.

CONCLUSION

Together, above findings proved the significant role of FZD6 in depression through its effect on hippocampal cell proliferation and its ability to regulate canonical Wnt/β-catenin pathway.

New pharmacotherapies to tackle the unmet needs in bipolar disorder: a focus on acute suicidality

INTRODUCTION

Suicidal behavior is relatively frequent in patients with bipolar disorder (BD) and constitutes their most frequent cause of death. Suicide rates remain high in patients with BD despite adherence to guidelines recommending lithium as first line, and/or antidepressants, antipsychotics, psychotherapy, psychosocial interventions, and electroconvulsive therapy. Hence the need to identify more effective and rapid anti-suicide interventions.

AREAS COVERED

To tackle the unmet needs of pharmacotherapy, we investigated the PubMed database on 24-25 January 2024 using strategies like ('acute suicid*'[ti] OR 'suicide crisis syndrome' OR 'acute suicidal affective disturbance') AND (lithium[ti] OR clozapine[ti]), which obtained 3 results, and ('acute suicid*'[ti] OR 'suicide crisis syndrome' OR 'acute suicidal affective disturbance') AND (ketamine[ti] OR esketamine[ti] OR NMDA[ti] OR glutamat*[ti]), which yielded 14 results. We explored glutamatergic abnormalities in BD and suicide and found alterations in both. The noncompetitive NMDS antagonist ketamine and its S-enantiomer esketamine reportedly decrease acute suicidality.

EXPERT OPINION

Intranasal esketamine or subcutaneous ketamine, single-bolus or intravenous, and possibly other glutamate receptor modulators may improve suicidal behavior in patients with unipolar and bipolar depression. This may be achieved through prompt remodulation of glutamate activity. The correct use of glutamatergic modulators could reduce acute suicidality and mortality in patients with BD.

Presenilin-2 knock-In mice show severe depressive behavior via DVL3 downregulation

INTRODUCTION

Alzheimer's disease (AD) is the most common form of dementia. Depression is one of the most critical psychiatric complications of AD, and 20%-30% of patients with AD experience symptoms of depression. Phospho-glycogen synthase kinase-3 beta (GSK3β) is known to be associated with AD and depression. Furthermore, the role of disheveled (DVL) is known to regulate GSK3β. Moreover, presenilin-2 (PS2) and DVL have cross-talk with each other. Also, it is widely hypothesized that stress leads to hypersecretion of cortisol and is thus associated with depression. Dickkopf WNT signaling pathway inhibitor-1 (DKK-1) is a crucial factor regulating depression and both amyloid beta (Aβ) and phosphorylation of tau are widely known as a biomarker of AD.

METHODS

To investigate the relationship between AD and depression, and possible pathways connecting the two diseases, we examined memory function and depression-related behavior test results in PS2 knock-in AD mice (PS2 MT). Next, we confirmed that there are relationships between DVL, depression, and cognitive disease through the comparative toxicogenomics database (https://ctdbase.org) and STRING (https://string-db.org) database.

RESULTS

PS2 knock-in mice showed much more severe memory impairment and depression than PS2 wild-type mice (PS2 WT). In AD-related behavioral experiments, PS2 MT mice showed more memory dysfunction compared with PS2 WT group mice. Moreover, Aβ and phosphorylation of tau showed higher expression in PS2 MT mice than in PS2 WT mice. Depression-related behavioral tests showed that PS2 MT mice exhibited more depressive behaviors than PS2 WT mice. Furthermore, both higher cortisol levels and higher expression of DKK-1 were found in PS2 MT mice relative to PS2 WT mice. The results indicated that there is a relationship between DVL and the release of AD-related mediators and expression of the depression-related glucocorticoid receptor and DKK-1. In the PS2 knock-in group, DVL was significantly decreased compared with the PS2 WT group.

CONCLUSION

Depression increases the risk of developing AD and other forms of dementia. Recent evidence indicates that depression symptoms could trigger changes in memory and thinking over time. However, it is recognized that there are no drugs to facilitate a full recovery for both AD and depression. However, our results suggest that AD and depression could be associated, and DVL could be a significant target for the association between AD and depression.

Research on the mechanism of antidepressive effect of Suanzaoren Decoction through TLR4/MyD88/NF-κB pathway and Wnt/β-catenin pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Increased inflammatory response and disruption of neuroplasticity are important mechanisms in the hypothesis of the pathogenesis of depression. Thus, these two aspects are conducive to the development of treatments for depression. Suanzaoren Decoction (SZRD) is a classic traditional Chinese medicine compound for the treatment of insomnia, which can clinically relieve depression symptoms, but its antidepressant pharmacological mechanism remains to be elucidated.

AIM OF THIS STUDY

Based on the hypothesis of inflammation and neuroplasticity in depression, this study aimed to investigate the antidepressant effect of SZRD and its specific molecular mechanism through chronic unpredictable mild stress (CUMS) induced SD rat model and lipopolysaccharide (LPS) induced BV2 cell neuroinflammation model.

MATERIALS AND METHODS

The body weight and behavioral indexes of CUMS model rats treated with orally or without oral SZRD for 4 weeks were detected. Hematoxylin and eosin staining was used to observe brain pathological damage. Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) staining was used to observe neuronal apoptosis. Immunofluorescence, ELISA kit and Western blotting were used to detect the inflammatory index Iba-1 and inflammatory factors, as well as the important inflammatory pathway TLR4/MyD88/NF-κB. Enzyme linked immunosorbent assay (ELISA) and western blotting were used to detect neuroplasticity indexes proteins-brain-derived neurotrophic factor (BDNF), presynaptic membrane protein-synaptophysin (SYP), and postsynaptic protein- 95(PSD95), and the key pathway Wnt/β-catenin. The possible mechanism of SZRD antidepressant was further explored in LPS-induced BV2 cells.

RESULTS

In vivo and in vitro experiments showed that SZRD treatment significantly reversed the depression-like behaviors in rats, decreased the levels of inflammatory factors and increased the expression levels of BDNF, SYP, PSD95 in depression model rats. Furthermore, SZRD treatment inhibited the activation of TLR4/MyD88/NF-κB and Wnt/β-catenin pathways and reduced the massive nuclear translocation of NF-κB and β-catenin. The addition of NF-κB pathway agonists could partially offset the inhibitory effect of SZRD on the Wnt pathway, and the addition of Wnt pathway agonists could also partially offset the inhibitory effect of SZRD on the TLR4 pathway.

CONCLUSION

This study suggestted that SZRD may exert its antidepressant effect by regulating TLR4/MyD88/NF-κB pathway and Wnt/β-catenin pathway in combination.

Second messengers and their importance for novel drug treatments of patients with bipolar disorder

Second messenger systems, like the cyclic nucleotide, glycogen synthase kinase-3β, phosphoinositide, and arachidonic acid cascades, are involved in bipolar disorder (BD). We investigated their role on the development of novel therapeutic drugs using second messenger mechanisms. PubMed search and narrative review. We used all relevant keywords for each second messenger cascade combining it with BD and related terms and combined all with novel/innovative treatments/drugs. Our search produced 31 papers most were reviews, and focussed on the PI3K/AKT-GSK-3β/Nrf2-NF-ĸB pathways. Only two human randomized clinical trials were identified, of ebselen, an antioxidant, and celecoxib, a cyclooxygenase-2 inhibitor, both with poor unsatisfactory results. Despite the fact that all second messenger systems are involved in the pathophysiology of BD, there are few experiments with novel drugs using these mechanisms. These mechanisms are a neglected and potentially major opportunity to transform the treatment of bipolar illness.

Proteomic biomarkers of Kleine-Levin syndrome

STUDY OBJECTIVES

Kleine-Levin syndrome (KLS) is characterized by relapsing-remitting episodes of hypersomnia, cognitive impairment, and behavioral disturbances. We quantified cerebrospinal fluid (CSF) and serum proteins in KLS cases and controls.

METHODS

SomaScan was used to profile 1133 CSF proteins in 30 KLS cases and 134 controls, while 1109 serum proteins were profiled in serum from 26 cases and 65 controls. CSF and serum proteins were both measured in seven cases. Univariate and multivariate analyses were used to find differentially expressed proteins (DEPs). Pathway and tissue enrichment analyses (TEAs) were performed on DEPs.

RESULTS

Univariate analyses found 28 and 141 proteins differentially expressed in CSF and serum, respectively (false discovery rate <0.1%). Upregulated CSF proteins included IL-34, IL-27, TGF-b, IGF-1, and osteonectin, while DKK4 and vWF were downregulated. Pathway analyses revealed microglial alterations and disrupted blood-brain barrier permeability. Serum profiles show upregulation of Src-family kinases (SFKs), proteins implicated in cellular growth, motility, and activation. TEA analysis of up- and downregulated proteins revealed changes in brain proteins (p < 6 × 10-5), notably from the pons, medulla, and midbrain. A multivariate machine-learning classifier performed robustly, achieving a receiver operating curve area under the curve of 0.90 (95% confidence interval [CI] = 0.78-1.0, p = 0.0006) in CSF and 1.0 (95% CI = 1.0-1.0, p = 0.0002) in serum in validation cohorts, with some commonality across tissues, as the model trained on serum sample also discriminated CSF samples of controls versus KLS cases.

CONCLUSIONS

Our study identifies proteomic KLS biomarkers with diagnostic potential and provides insight into biological mechanisms that will guide future research in KLS.

Brain gyrification in bipolar disorder: a systematic review of neuroimaging studies

Bipolar disorder (BD) is a severe mental illness with a strong genetic component. Genetic variations have been involved in the risk of this disorder, including those mediating brain function and neurodevelopment. Early neurodevelopment and neuroprogression processes could be reflected in brain gyrification patterns and help optimize the prediction and diagnosis of such disorders that is often delayed. Previous neuroimaging studies using this measure in patients with bipolar disorder revealed controversial results. This systematic review aimed to summarize available neuroimaging investigations on gyrification in BD compared to healthy controls (HC) and/or other psychiatric groups. Fourteen studies including 733 patients with BD, 585 patients with schizophrenia (SCZ), 90 with schizoaffective disorder (SZA), and 1380 healthy subjects were identified. Overall, a heterogeneous pattern of gyrification emerged between patients with BD and HC. Interestingly, increased gyrification or no differences were also observed in patients with BD compared to those with the schizophrenia-spectrum disorders. Furthermore, relatives of patients with BD showed lower or no differences in gyrification compared to healthy subjects without a family history of affective illness. Differences in the design and in methodological approaches could have contributed to the heterogeneity of the findings. The current review supports an altered brain gyrification pattern that underlies the pathophysiology of BD spanning large anatomical and functional neural networks, associated with altered cognitive functioning, difficulties in processing and affective regulation, and clinical symptoms. Longitudinal studies are needed to test different bipolar phenotypes and pharmacological effects on gyrification.

Identification of a Novel Functional Non-synonymous Single Nucleotide Polymorphism in Frizzled Class Receptor 6 Gene for Involvement in Depressive Symptoms

Although numerous susceptibility loci for depression have been identified in recent years, their biological function and molecular mechanism remain largely unknown. By using an exome-wide association study for depressive symptoms assessed by the Center for Epidemiological Studies Depression (CES-D) score, we discovered a novel missense single nucleotide polymorphism (SNP), rs61753730 (Q152E), located in the fourth exon of the frizzled class receptor 6 gene (FZD6), which is a potential causal variant and is significantly associated with the CES-D score. Computer-based in silico analysis revealed that the protein configuration and stability, as well as the secondary structure of FZD6 differed greatly between the wild-type (WT) and Q152E mutant. We further found that rs61753730 significantly affected the luciferase activity and expression of FZD6 in an allele-specific way. Finally, we generated Fzd6-knockin (Fzd6-KI) mice with rs61753730 mutation using the CRISPR/Cas9 genome editing system and found that these mice presented greater immobility in the forced swimming test, less preference for sucrose in the sucrose preference test, as well as decreased center entries, center time, and distance traveled in the open filed test compared with WT mice after exposed to chronic social defeat stress. These results indicate the involvement of rs61753730 in depression. Taken together, our findings demonstrate that SNP rs61753730 is a novel functional variant and plays an important role in depressive symptoms.

DNA Methylation Markers and Prediction Model for Depression and Their Contribution for Breast Cancer Risk

Background

Major depressive disorder (MDD) has become a leading cause of disability worldwide. However, the diagnosis of the disorder is dependent on clinical experience and inventory. At present, there are no reliable biomarkers to help with diagnosis and treatment. DNA methylation patterns may be a promising approach for elucidating the etiology of MDD and predicting patient susceptibility. Our overarching aim was to identify biomarkers based on DNA methylation, and then use it to propose a methylation prediction score for MDD, which we hope will help us evaluate the risk of breast cancer.

Methods

Methylation data from 533 samples were extracted from the Gene Expression Omnibus (GEO) database, of which, 324 individuals were diagnosed with MDD. Statistical difference of DNA Methylation between Promoter and Other body region (SIMPO) score for each gene was calculated based on the DNA methylation data. Based on SIMPO scores, we selected the top genes that showed a correlation with MDD in random resampling, then proposed a methylation-derived Depression Index (mDI) by combining the SIMPO of the selected genes to predict MDD. A validation analysis was then performed using additional DNA methylation data from 194 samples extracted from the GEO database. Furthermore, we applied the mDI to construct a prediction model for the risk of breast cancer using stepwise regression and random forest methods.

Results

The optimal mDI was derived from 426 genes, which included 245 positive and 181 negative correlations. It was constructed to predict MDD with high predictive power (AUC of 0.88) in the discovery dataset. In addition, we observed moderate power for mDI in the validation dataset with an OR of 1.79. Biological function assessment of the 426 genes showed that they were functionally enriched in Eph Ephrin signaling and beta-catenin Wnt signaling pathways. The mDI was then used to construct a predictive model for breast cancer that had an AUC ranging from 0.70 to 0.67.

Conclusion

Our results indicated that DNA methylation could help to explain the pathogenesis of MDD and assist with its diagnosis.

The Gender-Specific Interaction of DVL3 and GSK3β Polymorphisms on Major Depressive Disorder Susceptibility in a Chinese Han Population: A Case-Control Study

Based on the “oxidative stress hypothesis” of major depressive disorder (MDD), cells regulate their structure through the Wnt pathway. Little is known regarding the interactions of dishevelled 3 (DVL3) and glycogen synthase kinase 3 beta (GSK3β) polymorphisms with MDD. The aim of the current study was to verify the relationship between DVL3 and GSK3β genetic variants in a Chinese Han population and further to evaluate whether these interactions exhibit gender-specificity. A total of 1136 participants, consisting of 541 MDD patients and 595 healthy subjects, were recruited. Five single-nucleotide polymorphisms (SNPs) of DVL3/GSK3β were selected to assess their interaction by use of a generalized multifactor dimensionality reduction method. The genotype and haplotype frequencies of DVL3/GSK3β polymorphisms were significantly different between patients and controls for DVL3 rs1709642 ( $P<0.01$ ) and GSK3β rs334558, rs6438552, and rs2199503 ( $P<0.01$ ). In addition, our results also showed that there were significant interaction effects between DVL3 and GSK3β polymorphisms and the risk of developing MDD, particularly in women. The interaction between DVL3 (rs1709642) and GSK3β (rs334558, rs6438552) showed a cross-validation (CV) consistency of 10/10, a $P$ value of 0.001, and a testing accuracy of 59.22%, which was considered as the best generalized multifactor dimensionality reduction (GMDR) model. This study reveals the interaction between DVL3 and GSK3β polymorphisms on MDD susceptibility in a female Chinese Han population. The effect of gender should be taken into account in future studies that seek to explore the genetic predisposition to MDD relative to the DVL3 and GSK3β genes.

An insight into crosstalk among multiple signaling pathways contributing to epileptogenesis

Despite the years of research, epilepsy remains uncontrolled in one-third of afflicted individuals and poses a health and economic burden on society. Currently available anti-epileptic drugs mainly target the excitatory-inhibitory imbalance despite targeting the underlying pathophysiology of the disease. Recent research focuses on understanding the pathophysiologic mechanisms that lead to seizure generation and on possible new treatment avenues for preventing epilepsy after a brain injury. Various signaling pathways, including the mechanistic target of rapamycin (mTOR) pathway, mitogen-activated protein kinase (MAP-ERK) pathway, JAK-STAT pathway, wnt/β-catenin signaling, cAMP pathway, and jun kinase pathway, have been suggested to play an essential role in this regard. Recent work suggests that the mTOR pathway intervenes epileptogenesis and proposes that mTOR inhibitors may have antiepileptogenic properties for epilepsy. In the same way, several animal studies have indicated the involvement of the Wnt signaling pathway in neurogenesis and neuronal death induced by seizures in different phases (acute and chronic) of seizure development. Various studies have also documented the activation of JAK-STAT signaling in epilepsy and cAMP involvement in epileptogenesis through CREB (cAMP response element-binding protein). Although studies are there, the mechanism for how components of these pathways mediate epileptogenesis requires further investigation. This review summarises the current role of various signaling pathways involved in epileptogenesis and the crosstalk among them. Furthermore, we will also discuss the mechanical base for the interaction between these pathways and how these interactions could be a new emerging promising target for future epilepsy therapies.

Resiniferatoxin Hampers the Nocifensive Response of Caenorhabditis elegans to Noxious Heat, and Pathway Analysis Revealed that the Wnt Signaling Pathway is Involved

Resiniferatoxin (RTX) is a metabolite extracted from Euphorbia resinifera. RTX is a potent capsaicin analog with specific biological activities resulting from its agonist activity with the transient receptor potential channel vanilloid subfamily member 1 (TRPV1). RTX has been examined as a pain reliever, and more recently, investigated for its ability to desensitize cardiac sensory fibers expressing TRPV1 to improve chronic heart failure (CHF) outcomes using validated animal models. Caenorhabditis elegans (C. elegans) expresses orthologs of vanilloid receptors activated by capsaicin, producing antinociceptive effects. Thus, we used C. elegans to characterize the antinociceptive properties and performed proteomic profiling to uncover specific signaling networks. After exposure to RTX, wild-type (N2) and mutant C. elegans were placed on petri dishes divided into quadrants for heat stimulation. The thermal avoidance index was used to phenotype each tested C. elegans experimental group. The data revealed for the first time that RTX can hamper the nocifensive response of C. elegans to noxious heat (32 - 35 °C). The effect was reversed 6 h after RTX exposure. Additionally, we identified the RTX target, the C. elegans transient receptor potential channel OCR-3. The proteomics and pathway enrichment analysis results suggest that Wnt signaling is triggered by the agonistic effects of RTX on C. elegans vanilloid receptors.

Early life and adult stress promote sex dependent changes in hypothalamic miRNAs and environmental enrichment prevents stress-induced miRNA and gene expression changes in rats

BACKGROUND

The hypothalamus plays a key role in the stress response. While early life stress (ELS) increases susceptibility to psychiatric disorders including major depressive disorder (MDD), acute stress during adulthood can also precipitate MDD after ELS.

AIM

Here, we tested the expression of miRNAs following ELS and susceptibility to depression-like behavior and whether sex or acute stress exacerbates this response. We also tested whether environmental enrichment (Enr) promotes early life and adult behavioral stress resilience and its effect on hypothalamic miRNA and gene expression. Following rat maternal separation (MS) as an ELS model, Enr from weaning through adulthood, and restraint (RS) as acute adult stress, we tested both animal behavior and miRNA expression in the hypothalamus. Target genes and their enrichment and ontology were analyzed using bioinformatic tools. Target gene expression changes were tested using qPCR, and miRNA promoter methylation was studied using methylated-DNA immunoprecipitation qPCR.

RESULTS

MS, Enr, RS, and sex altered hypothalamic miRNAs, including several previously reported in MS literature: miRs-29, - 124, - 132, - 144, - 504. Sex had a significant effect on the greatest number of miRNAs. Also, Enr reversed downregulation of miR-29b-1-5p and -301b-3p in MS. qPCR showed that MAPK6 and MMP19, targets of miR-301b-3p, were upregulated in MS and reversed by Enr. Additionally, miR-219a was hypermethylated in MS coinciding with decreased miR-219a expression.

CONCLUSIONS

This study found that sex plays a critical role in the hypothalamic miRNA response to both ELS and acute stress, with males expressing greater changes following postnatal stress. Moreover, enrichment significantly altered behavior as well as hypothalamic miRNA expression and their gene targets. Because of its role as the initiator of the autonomic stress response and connection to hedonic and motivational behavior, the hypothalamic miRNA landscape may significantly alter both the short and long-term behavioral response to stress.

Casein kinase 1 epsilon and circadian misalignment impact affective behaviours in mice

Affective behaviours and mental health are profoundly affected by disturbances in circadian rhythms. Casein kinase 1 epsilon (CSNK1E) is a core component of the circadian clock. Mice with tau or null mutation of this gene have shortened and lengthened circadian period respectively. Here, we examined anxiety-like, fear, and despair behaviours in both male and female mice of these two different mutants. Compared with wild-type mice, we found reductions in fear and anxiety-like behaviours in both mutant lines and in both sexes, with the tau mutants exhibiting the greatest phenotypic changes. However, the behavioural despair had distinct phenotypic patterns, with markedly less behavioural despair in female null mutants, but not in tau mutants of either sex. To determine whether abnormal light entrainment of tau mutants to 24-h light-dark cycles contributes to these phenotypic differences, we also examined these behaviours in tau mutants on a 20-h light-dark cycle close to their endogenous circadian period. The normalized entrainment restored more wild-type-like behaviours for fear and anxiety, but it induced behavioural despair in tau mutant females. These data show that both mutations of Csnk1e broadly affect fear and anxiety-like behaviours, while the effects on behavioural despair vary with genetics, photoperiod, and sex, suggesting that the mechanisms by which Csnk1e affects fear and anxiety-like behaviours may be similar, but distinct from those affecting behavioural despair. Our study also provides experimental evidence in support of the hypothesis of beneficial outcomes from properly entrained circadian rhythms in terms of the anxiety-like and fear behaviours.

Genetic neuroimaging of bipolar disorder: a systematic 2017-2020 update

There is evidence of genetic polymorphism influences on brain structure and function, genetic risk in bipolar disorder (BD), and neuroimaging correlates of BD. How genetic influences related to BD could be reflected on brain changes in BD has been efficiently reviewed in a 2017 systematic review. We aimed to confirm and extend these findings through a Preferred Reporting Items for Systematic reviews and Meta-Analyses-based systematic review. Our study allowed us to conclude that there is no replicated finding in the timeframe considered. We were also unable to further confirm prior results of the BDNF gene polymorphisms to affect brain structure and function in BD. The most consistent finding is an influence of the CACNA1C rs1006737 polymorphism in brain connectivity and grey matter structure and function. There was a tendency of undersized studies to obtain positive results and large, genome-wide polygenic risk studies to find negative results in BD. The neuroimaging genetics in BD field is rapidly expanding.

The Role of Gut Microbiota in the High-Risk Construct of Severe Mental Disorders: A Mini Review

Severe mental disorders (SMD) are highly prevalent psychiatric conditions exerting an enormous toll on society. Therefore, prevention of SMD has received enormous attention in the last two decades. Preventative approaches are based on the knowledge and detailed characterization of the developmental stages of SMD and on risk prediction. One relevant biological component, so far neglected in high risk research, is microbiota. The human microbiota consists in the ensemble of microbes, including viruses, bacteria, and eukaryotes, that inhabit several ecological niches of the organism. Due to its demonstrated role in modulating illness and health, as well in influencing behavior, much interest has focused on the characterization of the microbiota inhabiting the gut. Several studies in animal models have shown the early modifications in the gut microbiota might impact on neurodevelopment and the onset of deficits in social behavior corresponding to distinct neurosignaling alterations. However, despite this evidence, only one study investigated the effect of altered microbiome and risk of developing mental disorders in humans, showing that individuals at risk for SMD had significantly different global microbiome composition than healthy controls. We then offer a developmental perspective and provided mechanistic insights on how changes in the microbiota could influence the risk of SMD. We suggest that the analysis of microbiota should be included in the comprehensive assessment generally performed in populations at high risk for SMD as it can inform predictive models and ultimately preventative strategies.

The Role of the Gastrointestinal Mucus System in Intestinal Homeostasis: Implications for Neurological Disorders

Mucus is integral to gut health and its properties may be affected in neurological disease. Mucus comprises a hydrated network of polymers including glycosylated mucin proteins. We propose that factors that influence the nervous system may also affect the volume, viscosity, porosity of mucus composition and subsequently, gastrointestinal (GI) microbial populations. The gut has its own intrinsic neuronal network, the enteric nervous system, which extends the length of the GI tract and innervates the mucosal epithelium. The ENS regulates gut function including mucus secretion and renewal. Both dysbiosis and gut dysfunction are commonly reported in several neurological disorders such as Parkinson's and Alzheimer's disease as well in patients with neurodevelopmental disorders including autism. Since some microbes use mucus as a prominent energy source, changes in mucus properties could alter, and even exacerbate, dysbiosis-related gut symptoms in neurological disorders. This review summarizes existing knowledge of the structure and function of the mucus of the GI tract and highlights areas to be addressed in future research to better understand how intestinal homeostasis is impacted in neurological disorders.

Wnt/β-Catenin Signaling in Neural Stem Cell Homeostasis and Neurological Diseases

Neural stem/progenitor cells (NSCs) maintain the ability of self-renewal and differentiation and compose the complex nervous system. Wnt signaling is thought to control the balance of NSC proliferation and differentiation via the transcriptional coactivator β-catenin during brain development and adult tissue homeostasis. Disruption of Wnt signaling may result in developmental defects and neurological diseases. Here, we summarize recent findings of the roles of Wnt/β-catenin signaling components in NSC homeostasis for the regulation of functional brain circuits. We also suggest that the potential role of Wnt/β-catenin signaling might lead to new therapeutic strategies for neurological diseases, including, but not limited to, spinal cord injury, Alzheimer's disease, Parkinson's disease, and depression.

Gene expression in peripheral blood in treatment-free major depression

BACKGROUND

Peripheral gene expression of several molecular pathways has been studied in major depressive disorder (MDD) with promising results. We sought to investigate some of these genes in a treatment-free Latino sample of Mexican descent.

MATERIAL AND METHODS

The sample consisted of 50 MDD treatment-free cases and 50 sex and age-matched controls. Gene expression of candidate genes of neuroplasticity (BDNF, p11, and VGF), inflammation (IL1A, IL1B, IL4, IL6, IL7, IL8, IL10, MIF, and TNFA), the canonical Wnt signaling pathway (TCF7L2, APC, and GSK3B), and mTOR, was compared in cases and controls. RNA was obtained from blood samples. We used bivariate analyses to compare subjects versus control mean mRNA quantification of target genes and lineal regression modelling to test for effects of age and body mass index on gene expression.

RESULTS

Most subjects were female (66%) with a mean age of 26.7 (SD 7.9) years. Only GSK3B was differentially expressed between cases and controls at a statistically significant level (p = 0.048). TCF7L-2 showed the highest number of correlations with MDD-related traits, yet these were modest in size.

DISCUSSION

GSK3B encodes a moderator of the canonical Wnt signaling pathway. It has a role in neuroplasticity, neuroprotection, depression, and other psychiatric phenotypes. We found that adding population diversity has the potential to elicit distinct peripheral gene expression markers in MDD and MDD-related traits. However, our results should only be considered as hypothesis-generating research that merits further replication in larger cohorts of similar ancestry.

A computationally inspired in-vivo approach identifies a link between amygdalar transcriptional heterogeneity, socialization and anxiety

Pharmaceutical breakthroughs for anxiety have been lackluster in the last half-century. Converging behavior and limbic molecular heterogeneity has the potential to revolutionize biomarker-driven interventions. However, current in vivo models too often deploy artificial systems including directed evolution, mutations and fear induction, which poorly mirror clinical manifestations. Here, we explore transcriptional heterogeneity of the amygdala in isogenic mice using an unbiased multi-dimensional computational approach that segregates intra-cohort reactions to moderate situational adversity and intersects it with high content molecular profiling. We show that while the computational approach stratifies known features of clinical anxiety including nitric oxide, opioid and corticotropin signaling, previously unrecognized druggable biomarkers emerge, such as calpain11 and scand1. Through ingenuity pathway analyses, we further describe a role for neurosteroid estradiol signaling, heat shock proteins, ubiquitin ligases and lipid metabolism. In addition, we report a remarkable behavioral pattern that maps to molecular features of anxiety in mice through counterphobic social attitudes, which manifest as increased, yet spatially distant socialization. These findings provide an unbiased approach for interrogating anxiolytics, and hint toward biomarkers underpinning behavioral and social patterns that merit further exploration.

REST/NRSF transcription factor is overexpressed in hippocampus of patients with drug-resistant mesial temporal lobe epilepsy

The Repressor Element-1 Silencing Transcription factor or Neuron-Restrictive Silencer Factor (REST/NRSF) is a zinc finger repressor transcription factor of the Kruppel family. Several studies in experimental models have shown that overexpression of REST/NRSF occurs after the induction of seizures. In the present study, the expression of REST/NRSF (messenger ribonucleic acid (mRNA) and protein) was evaluated in the hippocampus of 28 patients with drug-resistant mesial temporal lobe epilepsy (MTLE) and their correlation with clinical variables and comorbid anxiety and depression. The REST/NRSF protein expression was augmented in an age-dependent manner in the hippocampus of autopsied subjects. However, this condition was not observed in patients with MTLE, in whom overexpression of this transcription factor occurred at both the mRNA and protein levels. The correlations with clinical variables showed that the frequency of epileptic seizures was proportional to the protein expression of REST/NRSF. The results revealed that the overexpression of REST/NRSF was more evident in patients with MTLE without anxiety and depression. Our data indicate that the expression of REST/NRSF is modified in patients with MTLE. This condition has implications in the pathophysiology of this disorder, making it a potential candidate for the optimization of clinical treatments.

GSK3β: a plausible mechanism of cognitive and hippocampal changes induced by erythropoietin treatment in mood disorders?

Mood disorders are associated with significant psychosocial and occupational disability. It is estimated that major depressive disorder (MDD) will become the second leading cause of disability worldwide by 2020. Existing pharmacological and psychological treatments are limited for targeting cognitive dysfunctions in mood disorders. However, growing evidence from human and animal studies has shown that treatment with erythropoietin (EPO) can improve cognitive function. A recent study involving EPO-treated patients with mood disorders showed that the neural basis for their cognitive improvements appeared to involve an increase in hippocampal volume. Molecular mechanisms underlying hippocampal changes have been proposed, including the activation of anti-apoptotic, antioxidant, pro-survival and anti-inflammatory signalling pathways. The aim of this review is to describe the potential importance of glycogen synthase kinase 3-beta (GSK3β) as a multi-potent molecular mechanism of EPO-induced hippocampal volume change in mood disorder patients. We first examine published associations between EPO administration, mood disorders, cognition and hippocampal volume. We then highlight evidence suggesting that GSK3β influences hippocampal volume in MDD patients, and how this could assist with targeting more precise treatments particularly for cognitive deficits in patients with mood disorders. We conclude by suggesting how this developing area of research can be further advanced, such as using pharmacogenetic studies of EPO treatment in patients with mood disorders.

Dvl3 polymorphism interacts with life events and pro-inflammatory cytokines to influence major depressive disorder susceptibility

The purpose of this study is to explore Dvl3 variants and their interaction with negative life events on MDD susceptibility in a Chinese Han population. Additionally, we also attempted to identify whether there is an association between Dvl3 variants and pro-inflammatory cytokines. A total of 1102 participants, consisting of 550 patients with MDD and 552 healthy subjects, were recruited for genotyping by TaqMan allelic discrimination assay. Pro-inflammatory cytokine mRNA levels in peripheral blood were measured by QPCR. After the assessment of negative life events by the Life Events Scale, the Dvl3 gene–environment interaction (G × E) and risk factors were evaluated using generalized multifactor dimensionality reduction method (GMDR) and logistic regression analysis, respectively. This study is the first to reveal the interaction between Dvl3 allelic variations and negative life events as well as pro-inflammatory cytokines on MDD susceptibility in a Chinese Han population.

Wnt/β-catenin signaling as a potential target for novel epilepsy therapies

Epilepsy is one of the most common neurological disorders, and yet many afflicted individuals are resistant to all available therapeutic treatments. Existing pharmaceutical treatments function primarily to reduce hyperexcitability and prevent seizures, but fail to influence the underlying pathophysiology of the disorder. Recently, research efforts have focused on identifying alternative mechanistic targets for anti-epileptogenic therapies that can prevent the development of chronic epilepsy. The Wnt/β-catenin pathway, one possible target, has been demonstrated to be disrupted in both acute and chronic phases of epilepsy. Wnt/β-catenin signaling can regulate many seizure-induced changes in the brain, including neurogenesis and neuronal death, as well as can influence seizure susceptibility and potentially the development of chronic epilepsy. Several genome-wide studies and in vivo knockout animal models have provided evidence for an association between disrupted Wnt/β-catenin signaling and epilepsy. Furthermore, approved pharmaceutical drugs and other small molecule compounds that target components of the β-catenin destruction complex or antagonize endogenous inhibitors of the pathway have shown to be protective following seizures. However, additional studies are needed to determine the optimal time period in which modulation of the pathway may be most beneficial. Overall, disrupted molecular networks such as Wnt/β-catenin signaling, could be a promising anti-epileptogenic target for future epilepsy therapies.

Exploring the Wnt signaling pathway in schizophrenia and bipolar disorder

The Wnt signaling pathway plays a crucial role in neurodevelopment and in regulating the function and structure of the adult nervous system. Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental disorders with evidence of subtle neurodevelopmental, structural and functional neuronal abnormalities. We aimed to elucidate the role of aberrant regulation of the Wnt system in these disorders by evaluating plasma levels of secreted Wnt modulators in patients (SCZ = 551 and BD = 246) and healthy controls (HCs = 639) using enzyme immune-assay. We also investigated the expression of 141 Wnt-related genes in whole blood in a subsample (SCZ = 338, BD = 241, and HCs = 263) using microarray analysis. Both SCZ and BD had dysregulated mRNA expression of Wnt-related genes favoring attenuated canonical (beta-catenin-dependent) signaling, and there were also indices of enhanced non-canonical Wnt signaling. In particular, FZD7, which may activate all Wnt pathways, but favors non-canonical signaling, and NFATc3, a downstream transcription factor and readout of the non-canonical Wnt/Ca²⁺ pathway, were significantly increased in SCZ and BD (p < 3 × 10^-4). Furthermore, patients had lower plasma levels of soluble dickkopf 1 and sclerostin (p < 0.01) compared with HC. Our findings suggest that SCZ and BD are characterized by abnormal Wnt gene expression and plasma protein levels, and we propose that drugs targeting the Wnt pathway may have a role in the treatment of severe mental disorders.

Ascorbic Acid to Manage Psychiatric Disorders

Ascorbate has critical roles in the central nervous system (CNS); it is a neuromodulator of glutamatergic, cholinergic, dopaminergic, and γ-aminobutyric acid (GABA)-ergic neurotransmission, provides support and structure to neurons, and participates in processes such as differentiation, maturation, and survival of neurons. Over the past decade, antioxidant properties of ascorbate have been extensively characterized and now it is known that this compound is highly concentrated in the brain and neuroendocrine tissues. All this information raised the hypothesis that ascorbate may be involved in neurological disorders. Indeed, the biological mechanisms of ascorbate in health and disease and its involvement in homeostasis of the CNS have been the subject of extensive research. In particular, evidence for an association of this vitamin with schizophrenia, major depressive disorder, and bipolar disorder has been provided. Considering that conventional pharmacotherapy for the treatment of these neuropathologies has important limitations, this review aims to explore basic and human studies that implicate ascorbic acid as a potential therapeutic strategy. Possible mechanisms involved in the beneficial effects of ascorbic acid for the management of psychiatric disorders are also discussed.

Autistic and schizotypal traits and global functioning in bipolar I disorder

OBJECTIVE

To determine the expression of autistic and positive schizotypal traits in a large sample of adults with bipolar I disorder (BD I), and the effect of co-occurring autistic and positive schizotypal traits on global functioning in BD I.

METHOD

Autistic and positive schizotypal traits were self-assessed in 797 individuals with BD-I recruited by the Bipolar Disorder Research Network. Differences in global functioning (rated using the Global Assessment Scale) during lifetime worst depressive and manic episodes (GASD and GASM respectively) were calculated in groups with high/low autistic and positive schizotypal traits. Regression analyses assessed the interactive effect of autistic and positive schizotypal traits on global functioning.

RESULTS

47.2% (CI=43.7-50.7%) showed clinically significant levels of autistic traits, and 23.22% (95% CI=20.29-26.14) showed clinically significant levels of positive schizotypal traits. In the worst episode of mania, the high autistic, high positive schizotypal group had better global functioning compared to the other groups. Individual differences analyses showed that high levels of both traits were associated with better global functioning in both mood states.

LIMITATIONS

Autistic and schizotypal traits were assessed using self-rated questionnaires.

CONCLUSIONS

Expression of autistic and schizotypal traits in adults with BD I is prevalent, and may be important to predict illness aetiology, prognosis, and diagnostic practices in this population. Future work should focus on replicating these findings in independent samples, and on the biological and/or psychosocial mechanisms underlying better global functioning in those who have high levels of both autistic and positive schizotypal traits.

The antidepressant roles of Wnt2 and Wnt3 in stress-induced depression-like behaviors

Wnts-related signaling pathways have been reported to play roles in the pathogenesis of stress-induced depression-like behaviors. However, there is relatively few direct evidence to indicate the effect of Wnt ligands on this process. Here, we investigated the role of Wnts in mediating chronic restraint stress (CRS)-induced depression-like behaviors. We found that CRS induced a significant decrease in the expression of Wnt2 and Wnt3 in the ventral hippocampus (VH) but not in the dorsal hippocampus. Knocking down Wnt2 or Wnt3 in the VH led to impaired Wnt/β-catenin signaling, neurogenesis deficits and depression-like behaviors. In contrast, overexpression of Wnt2 or Wnt3 reversed CRS-induced depression-like behaviors. Moreover, Wnt2 and Wnt3 activated cAMP response element-binding protein (CREB) and there was CREB-dependent positive feedback between Wnt2 and Wnt3. Finally, fluoxetine treatment increased Wnt2 and Wnt3 levels in the VH and knocking down Wnt2 or Wnt3 abolished the antidepressant effect of fluoxetine. Taken together, our study indicates essential roles for Wnt2 and Wnt3 in CRS-induced depression-like behaviors and antidepressant.

The role of GSK-3 in treatment-resistant depression and links with the pharmacological effects of lithium and ketamine: A review of the literature

BACKGROUND

Since the discovery of antidepressants, new treatments have emerged with fewer side effects but no greater efficacy. Glycogen synthase kinase 3 β (GSK-3β), a kinase known for its activity on glycogen synthesis, has in the last few years raised growing interest in biological psychiatry. Several efficient treatments in major depression have an inhibitory effect on this kinase, which could be targeted in new mood disorder treatments.

METHODS

The aim of this review is to summarize findings concerning the intracellular pharmacologic effects of GSK-3β inhibitors on mood. After a brief description of the intracellular transduction pathways implicated in both GSK-3β and mood disorders, we reviewed the results demonstrating GSK-3β involvement in the effects of lithium and ketamine.

RESULTS

GSK-3β can be inhibited through several mechanisms such as serine phosphorylation or binding in a proteic scaffold and others. Its inhibition is implicated in numerous cellular pathways of interest involved in neuronal growth and architecture, cell survival, neurogenesis or synaptic plasticity. This inhibition appears to be both efficient and sufficient in improving mood in animal models. In human beings, several levels of evidence show GSK-3β inhibition with antidepressant use. Crucially, strong inhibition has been shown with lithium via the proteic scaffold PP2A/β-arrestin/AKT, and with the rapid antidepressant effect of ketamine via p70S6K.

CONCLUSION

Our review focuses on mechanisms whereby the GSK-3β pathway has a part in the antidepressant effect of lithium and ketamine. This article highlights the importance of translational research from cell and animal models to the clinical setting in order to develop innovative therapeutic targets.

Gene expression in major depressive disorder

The search for genetic variants underlying major depressive disorder (MDD) has not yet provided firm leads to its underlying molecular biology. A complementary approach is to study gene expression in relation to MDD. We measured gene expression in peripheral blood from 1848 subjects from The Netherlands Study of Depression and Anxiety. Subjects were divided into current MDD (N=882), remitted MDD (N=635) and control (N=331) groups. MDD status and gene expression were measured again 2 years later in 414 subjects. The strongest gene expression differences were between the current MDD and control groups (129 genes at false-discovery rate, FDR<0.1). Gene expression differences across MDD status were largely unrelated to antidepressant use, inflammatory status and blood cell counts. Genes associated with MDD were enriched for interleukin-6 (IL-6)-signaling and natural killer (NK) cell pathways. We identified 13 gene expression clusters with specific clusters enriched for genes involved in NK cell activation (downregulated in current MDD, FDR=5.8 × 10(-5)) and IL-6 pathways (upregulated in current MDD, FDR=3.2 × 10(-3)). Longitudinal analyses largely confirmed results observed in the cross-sectional data. Comparisons of gene expression results to the Psychiatric Genomics Consortium (PGC) MDD genome-wide association study results revealed overlap with DVL3. In conclusion, multiple gene expression associations with MDD were identified and suggest a measurable impact of current MDD state on gene expression. Identified genes and gene clusters are enriched with immune pathways previously associated with the etiology of MDD, in line with the immune suppression and immune activation hypothesis of MDD.

Recurrent major depression and right hippocampal volume: A bivariate linkage and association study

Previous work has shown that the hippocampus is smaller in the brains of individuals suffering from major depressive disorder (MDD) than those of healthy controls. Moreover, right hippocampal volume specifically has been found to predict the probability of subsequent depressive episodes. This study explored the utility of right hippocampal volume as an endophenotype of recurrent MDD (rMDD). We observed a significant genetic correlation between the two traits in a large sample of Mexican American individuals from extended pedigrees (ρg = -0.34, p = 0.013). A bivariate linkage scan revealed a significant pleiotropic quantitative trait locus on chromosome 18p11.31-32 (LOD = 3.61). Bivariate association analysis conducted under the linkage peak revealed a variant (rs574972) within an intron of the gene SMCHD1 meeting the corrected significance level (χ(2) = 19.0, p = 7.4 × 10(-5)). Univariate association analyses of each phenotype separately revealed that the same variant was significant for right hippocampal volume alone, and also revealed a suggestively significant variant (rs12455524) within the gene DLGAP1 for rMDD alone. The results implicate right-hemisphere hippocampal volume as a possible endophenotype of rMDD, and in so doing highlight a potential gene of interest for rMDD risk.

The emerging role of dopamine-glutamate interaction and of the postsynaptic density in bipolar disorder pathophysiology: Implications for treatment

Aberrant synaptic plasticity, originating from abnormalities in dopamine and/or glutamate transduction pathways, may contribute to the complex clinical manifestations of bipolar disorder (BD). Dopamine and glutamate systems cross-talk at multiple levels, such as at the postsynaptic density (PSD). The PSD is a structural and functional protein mesh implicated in dopamine and glutamate-mediated synaptic plasticity. Proteins at PSD have been demonstrated to be involved in mood disorders pathophysiology and to be modulated by antipsychotics and mood stabilizers. On the other side, post-receptor effectors such as protein kinase B (Akt), glycogen synthase kinase-3 (GSK-3) and the extracellular signal-regulated kinase (Erk), which are implicated in both molecular abnormalities and treatment of BD, may interact with PSD proteins, and participate in the interplay of the dopamine-glutamate signalling pathway. In this review, we describe emerging evidence on the molecular cross-talk between dopamine and glutamate signalling in BD pathophysiology and pharmacological treatment, mainly focusing on dysfunctions in PSD molecules. We also aim to discuss future therapeutic strategies that could selectively target the PSD-mediated signalling cascade at the crossroads of dopamine-glutamate neurotransmission.

Glia and immune cell signaling in bipolar disorder: insights from neuropharmacology and molecular imaging to clinical application

Bipolar disorder (BD) is a debilitating mental illness characterized by severe fluctuations in mood, sleep, energy and executive functioning. Pharmacological studies of selective serotonin reuptake inhibitors and the monoamine system have helped us to clinically understand bipolar depression. Mood stabilizers such as lithium and valproic acid, the first-line treatments for bipolar mania and depression, inhibit glycogen synthase kinase-3 beta (GSK-3β) and regulate the Wnt pathway. Recent investigations suggest that microglia, the resident immune cells of the brain, provide a physiological link between the serotonin system and the GSK-3β/Wnt pathway through neuroinflammation. We review the pharmacological, translational and brain imaging studies that support a role for microglia in regulating neurotransmitter synthesis and immune cell activation. These investigations provide a model for microglia involvement in the pathophysiology and phenotype of BD that may translate into improved therapies.

Gene expression: biomarker of antidepressant therapy?

While antidepressant therapy is an essential treatment of major depression, a substantial group of treated patients do not respond to therapy, or suffer from severe side effects. Moreover, the time of onset of the clinical improvement is often delayed. Antidepressants as currently available usually enhance serotonergic, noradrenergic and dopaminergic neurotransmission and may contribute to the inadequate remission rates for major depression. Therefore biomarkers enabling the identification of subgroups of patients and also finding unprecedented targets would provide the basis for personalized medication and thus improve treatment efficacy and reduce side effects. Several pharmacogenetic studies on antidepressant treatment response using single nucleotide polymorphism (SNPs) mapping have been performed but provided only modest findings. Therefore the analysis of gene expression to integrate genomic activity and environmental effects promises a new approach to cope with the complexity of factors influencing antidepressant treatment. Here gene expression studies focusing on candidate genes and genome-wide approaches using RNA derived from peripheral blood cells are reviewed. The most promising findings exist for hypothalamic-pituitary-adrenal (HPA) axis, inflammation and neuroplasticity related genes. However, straightforward translation into tailored treatment is still unlikely. Contradictory results limit the clinical use of the findings. Future studies are necessary, which could include functional analysis and consider gene-environment interactions.

Neurodevelopment in schizophrenia: the role of the wnt pathways

OBJECTIVES

To review the role of Wnt pathways in the neurodevelopment of schizophrenia.

METHODS

SYSTEMATIC PUBMED SEARCH, USING AS KEYWORDS ALL THE TERMS RELATED TO THE WNT PATHWAYS AND CROSSING THEM WITH EACH OF THE FOLLOWING AREAS: normal neurodevelopment and physiology, neurodevelopmental theory of schizophrenia, schizophrenia, and antipsychotic drug action.

RESULTS

Neurodevelopmental, behavioural, genetic, and psychopharmacological data point to the possible involvement of Wnt systems, especially the canonical pathway, in the pathophysiology of schizophrenia and in the mechanism of antipsychotic drug action. The molecules most consistently found to be associated with abnormalities or in antipsychotic drug action are Akt1, glycogen synthase kinase3beta, and beta-catenin. However, the extent to which they contribute to the pathophysiology of schizophrenia or to antipsychotic action remains to be established.

CONCLUSIONS

The study of the involvement of Wnt pathway abnormalities in schizophrenia may help in understanding this multifaceted clinical entity; the development of Wnt-related pharmacological targets must await the collection of more data.