Epigenetic Modifications in Schizophrenia and Related Disorders: Molecular Scars of Environmental Exposures and Source of Phenotypic Variability

Prenatal psychological distress and 11β-HSD2 gene expression in human placentas: Systematic review and meta-analysis

BACKGROUND

The placenta acts as a buffer to regulate the degree of fetal exposure to maternal cortisol through the 11-Beta Hydroxysteroid Dehydrogenase isoenzyme type 2 (11-β HSD2) enzyme. We conducted a systematic review and meta-analysis to assess the effect of prenatal psychological distress (PPD) on placental 11-β HSD2 gene expression and explore the related mechanistic pathways involved in fetal neurodevelopment.

METHODS

We searched PubMed, Embase, Scopus, APA PsycInfo®, and ProQuest Dissertations for observational studies assessing the association between PPD and 11-β HSD2 expression in human placentas. Adjusted regression coefficients (β) and corresponding 95% confidence intervals (CIs) were pooled based on three contextual PPD exposure groups: prenatal depression, anxiety symptoms, and perceived stress.

RESULTS

Of 3159 retrieved records, sixteen longitudinal studies involving 1869 participants across seven countries were included. Overall, exposure to PPD disorders showed weak negative associations with the placental 11-β HSD2 gene expression as follows: prenatal depression (β -0.01, 95% CI 0.05-0.02, I2=0%), anxiety symptoms (β -0.02, 95% CI 0.06-0.01, I2=0%), and perceived stress (β -0.01 95% CI 0.06-0.04, I2=62.8%). Third-trimester PPD exposure was more frequently associated with lower placental 11-β HSD2 levels. PPD and placental 11-β HSD2 were associated with changes in cortisol reactivity and the development of adverse health outcomes in mothers and children. Female-offspring were more vulnerable to PPD exposures.

CONCLUSION

The study presents evidence of a modest role of prenatal psychological distress in regulating placental 11-β HSD2 gene expression. Future prospective cohorts utilizing larger sample sizes or advanced statistical methods to enhance the detection of small effect sizes should be planned. Additionally, controlling for key predictors such as the mother's ethnicity, trimester of PPD exposure, mode of delivery, and infant sex is crucial for valid exploration of PPD effects on fetal programming.

Simultaneous EEG-fMRI Investigation of Rhythm-Dependent Thalamo-Cortical Circuits Alteration in Schizophrenia

Schizophrenia is accompanied by aberrant interactions of intrinsic brain networks. However, the modulatory effect of electroencephalography (EEG) rhythms on the functional connectivity (FC) in schizophrenia remains unclear. This study aims to provide new insight into network communication in schizophrenia by integrating FC and EEG rhythm information. After collecting simultaneous resting-state EEG-functional magnetic resonance imaging data, the effect of rhythm modulations on FC was explored using what we term "dynamic rhythm information." We also investigated the synergistic relationships among three networks under rhythm modulation conditions, where this relationship presents the coupling between two brain networks with other networks as the center by the rhythm modulation. This study found FC between the thalamus and cortical network regions was rhythm-specific. Further, the effects of the thalamus on the default mode network (DMN) and salience network (SN) were less similar under alpha rhythm modulation in schizophrenia patients than in controls ([Formula: see text]). However, the similarity between the effects of the central executive network (CEN) on the DMN and SN under gamma modulation was greater ([Formula: see text]), and the degree of coupling was negatively correlated with the duration of disease ([Formula: see text], [Formula: see text]). Moreover, schizophrenia patients exhibited less coupling with the thalamus as the center and greater coupling with the CEN as the center. These results indicate that modulations in dynamic rhythms might contribute to the disordered functional interactions seen in schizophrenia.

Potential Early Effect Biomarkers for Ambient Air Pollution Related Mental Disorders

Air pollution is one of the greatest environmental risks to health, with 99% of the world's population living where the World Health Organization's air quality guidelines were not met. In addition to the respiratory and cardiovascular systems, the brain is another potential target of air pollution. Population- and experiment-based studies have shown that air pollution may affect mental health through direct or indirect biological pathways. The evidence for mental hazards associated with air pollution has been well documented. However, previous reviews mainly focused on epidemiological associations of air pollution with some specific mental disorders or possible biological mechanisms. A systematic review is absent for early effect biomarkers for characterizing mental health hazards associated with ambient air pollution, which can be used for early warning of related mental disorders and identifying susceptible populations at high risk. This review summarizes possible biomarkers involved in oxidative stress, inflammation, and epigenetic changes linking air pollution and mental disorders, as well as genetic susceptibility biomarkers. These biomarkers may provide a better understanding of air pollution's adverse effects on mental disorders and provide future research direction in this arena.

Association of histone modification with the development of schizophrenia

Schizophrenia, influenced by genetic and environmental factors, may involve epigenetic alterations, notably histone modifications, in its pathogenesis. This review summarizes various histone modifications including acetylation, methylation, phosphorylation, ubiquitination, serotonylation, lactylation, palmitoylation, and dopaminylation, and their implications in schizophrenia. Current research predominantly focuses on histone acetylation and methylation, though other modifications also play significant roles. These modifications are crucial in regulating transcription through chromatin remodeling, which is vital for understanding schizophrenia's development. For instance, histone acetylation enhances transcriptional efficiency by loosening chromatin, while increased histone methyltransferase activity on H3K9 and altered histone phosphorylation, which reduces DNA affinity and destabilizes chromatin structure, are significant markers of schizophrenia.

Dissociation and misdiagnosis of schizophrenia in populations experiencing chronic discrimination and social defeat

As recently as the late 20th century, Schizophrenia, a category of mental illness with widely varying phenotypic symptoms, was believed by psychobiologists to be a genetically based disorder in which the environment played a limited etiological role. Yet a growing body of evidence indicates a strong correlation between schizophrenia and environmental factors. This theoretical paper explores the relationship between highly elevated rates of schizophrenia in some low-income minority communities worldwide and trauma-related dissociative symptoms that often mimic schizophrenia. Elevated rates of schizophrenia in racially and ethnically isolated, inner-city Black populations are well documented. This paper contains evidence proposing that this amplification in the rate of schizophrenia is mediated by childhood trauma, disorganized attachment, and social defeat. Further, evidence demonstrating how these three variables combine in early childhood to incubate dissociative disorders will also be conveyed. The misdiagnosis of dissociative disorders as schizophrenia is theorized to partially mediate the increased rate of schizophrenia in communities that experience high levels of racial/ethnic discrimination. It is argued that this misdiagnosis is often attributable to cultural misunderstanding and/or a lack of knowledge about dissociative disorders.

Causal relationship between schizophrenia and sex hormone binding globulin: A Mendelian randomization study

OBJECTIVE

The underlying etiology of schizophrenia is still not fully understood, and recent studies have pointed to a potential link between hormonal factors and the risk of developing this condition. Sex Hormone-Binding Globulin (SHBG) is a protein that regulates the bioavailability of sex hormones. However, the causal relationship between SHBG levels and schizophrenia remains unclear, this study aimed to investigate the causal relationship based on two-sample Mendelian randomization (MR) analysis.

METHODS

This study was based on the summary data of genome-wide association studies (GWAS) of schizophrenia and SHBG in European populations. Two-sample MR was applied, and genetic factors were used as instrumental variables, and the causal relationship between schizophrenia and SHBG was assessed.

RESULTS

We selected 79 single nucleotide polymorphisms with genome-wide significance from the schizophrenia GWAS as instrumental variables. The inverse variance weighting (IVW) method results showed that there is a causal relationship and a positive correlation between schizophrenia and female SHBG, with an odds ratio (OR) of 1.024 (95%CI: 1.007-1.042, P = 0.005), and this result was further confirmed by the Weighted median odds ratio (OR) of 1.032 (95%CI: 1.016-1.048, P = 5.58E-05) and the Weighted mode of 1.035 (95%CI: 1.004-1.067, P = 0.028). Schizophrenia and male SHBG also have a causal relationship and a positive correlation, with an odds ratio (OR) of 1.027 (95%CI: 1.007-1.047, P = 0.008).

CONCLUSION

This study found a positive correlation between schizophrenia and SHBG in both men and women through MR analysis, indicating that the level of SHBG may be elevated in patients with schizophrenia, regardless of gender.

Neuroinflammation and Schizophrenia: New Therapeutic Strategies through Psychobiotics, Nanotechnology, and Artificial Intelligence (AI)

The prevalence of schizophrenia, affecting approximately 1% of the global population, underscores the urgency for innovative therapeutic strategies. Recent insights into the role of neuroinflammation, the gut-brain axis, and the microbiota in schizophrenia pathogenesis have paved the way for the exploration of psychobiotics as a novel treatment avenue. These interventions, targeting the gut microbiome, offer a promising approach to ameliorating psychiatric symptoms. Furthermore, advancements in artificial intelligence and nanotechnology are set to revolutionize psychobiotic development and application, promising to enhance their production, precision, and effectiveness. This interdisciplinary approach heralds a new era in schizophrenia management, potentially transforming patient outcomes and offering a beacon of hope for those afflicted by this complex disorder.

Right superior frontal gyrus: A potential neuroimaging biomarker for predicting short-term efficacy in schizophrenia

Antipsychotic drug treatment for schizophrenia (SZ) can alter brain structure and function, but it is unclear if specific regional changes are associated with treatment outcome. Therefore, we examined the effects of antipsychotic drug treatment on regional grey matter (GM) density, white matter (WM) density, and functional connectivity (FC) as well as associations between regional changes and treatment efficacy. SZ patients (n = 163) and health controls (HCs) (n = 131) were examined by structural magnetic resonance imaging (sMRI) at baseline, and a subset of SZ patients (n = 77) were re-examined after 8 weeks of second-generation antipsychotic treatment to assess changes in regional GM and WM density. In addition, 88 SZ patients and 81 HCs were examined by resting-state functional MRI (rs-fMRI) at baseline and the patients were re-examined post-treatment to examine FC changes. The Positive and Negative Syndrome Scale (PANSS) and MATRICS Consensus Cognitive Battery (MCCB) were applied to measure psychiatric symptoms and cognitive impairments in SZ. SZ patients were then stratified into response and non-response groups according to PANSS score change (≥50 % decrease or <50 % decrease, respectively). The GM density of the right cingulate gyrus, WM density of the right superior frontal gyrus (SFG) plus 5 other WM tracts were reduced in the response group compared to the non-response group. The FC values between the right anterior cingulate and paracingulate gyrus and left thalamus were reduced in the entire SZ group (n = 88) after treatment, while FC between the right inferior temporal gyrus (ITG) and right medial superior frontal gyrus (SFGmed) was increased in the response group. There were no significant changes in regional FC among the non-response group after treatment and no correlations with symptom or cognition test scores. These findings suggest that the right SFG is a critical target of antipsychotic drugs and that WM density and FC alterations within this region could be used as potential indicators in predicting the treatment outcome of antipsychotics of SZ.

NrCAM-deficient mice exposed to chronic stress exhibit disrupted latent inhibition, a hallmark of schizophrenia

The neuronal cell adhesion molecule (NrCAM) is widely expressed and has important physiological functions in the nervous system across the lifespan, from axonal growth and guidance to spine and synaptic pruning, to organization of proteins at the nodes of Ranvier. NrCAM lies at the core of a functional protein network where multiple targets (including NrCAM itself) have been associated with schizophrenia. Here we investigated the effects of chronic unpredictable stress on latent inhibition, a measure of selective attention and learning which shows alterations in schizophrenia, in NrCAM knockout (KO) mice and their wild-type littermate controls (WT). Under baseline experimental conditions both NrCAM KO and WT mice expressed robust latent inhibition (p = 0.001). However, following chronic unpredictable stress, WT mice (p = 0.002), but not NrCAM KO mice (F < 1), expressed latent inhibition. Analyses of neuronal activation (c-Fos positive counts) in key brain regions relevant to latent inhibition indicated four types of effects: a single hit by genotype in IL cortex (p = 0.0001), a single hit by stress in Acb-shell (p = 0.031), a dual hit stress x genotype in mOFC (p = 0.008), vOFC (p = 0.020), and Acb-core (p = 0.032), and no effect in PrL cortex (p > 0.141). These results indicating a pattern of differential effects of genotype and stress support a complex stress × genotype interaction model and a role for NrCAM in stress-induced pathological behaviors relevant to schizophrenia and other psychiatric disorders.

Methylome-wide and meQTL analysis helps to distinguish treatment response from non-response and pathogenesis markers in schizophrenia

Schizophrenia is a complex condition with entwined genetic and epigenetic risk factors, posing a challenge to disentangle the intermixed pathological and therapeutic epigenetic signatures. To resolve this, we performed 850K methylome-wide and 700K genome-wide studies on the same set of schizophrenia patients by stratifying them into responders, non-responders, and drug-naïve patients. The key genes that signified the response were followed up using real-time gene expression studies to understand the effect of antipsychotics at the gene transcription level. The study primarily implicates hypermethylation in therapeutic response and hypomethylation in the drug-non-responsive state. Several differentially methylated sites and regions colocalized with the schizophrenia genome-wide association study (GWAS) risk genes and variants, supporting the convoluted gene-environment association. Gene ontology and protein-protein interaction (PPI) network analyses revealed distinct patterns that differentiated the treatment response from drug resistance. The study highlights the strong involvement of several processes related to nervous system development, cell adhesion, and signaling in the antipsychotic response. The ability of antipsychotic medications to alter the pathology by modulating gene expression or methylation patterns is evident from the general increase in the gene expression of response markers and histone modifiers and the decrease in class II human leukocyte antigen (HLA) genes following treatment with varying concentrations of medications like clozapine, olanzapine, risperidone, and haloperidol. The study indicates a directional overlap of methylation markers between pathogenesis and therapeutic response, thereby suggesting a careful distinction of methylation markers of pathogenesis from treatment response. In addition, there is a need to understand the trade-off between genetic and epigenetic observations. It is suggested that methylomic changes brought about by drugs need careful evaluation for their positive effects on pathogenesis, course of disease progression, symptom severity, side effects, and refractoriness.

Longitudinal MicroRNA Signature of Conversion to Psychosis

BACKGROUND AND HYPOTHESIS

The emergence of psychosis in ultra-high-risk subjects (UHR) is influenced by gene-environment interactions that rely on epigenetic mechanisms such as microRNAs. However, whether they can be relevant pathophysiological biomarkers of psychosis' onset remains unknown.

STUDY DESIGN

We present a longitudinal study of microRNA expression, measured in plasma by high-throughput sequencing at baseline and follow-up, in a prospective cohort of 81 UHR, 35 of whom developed psychosis at follow-up (converters). We combined supervised machine learning and differential graph analysis to assess the relative weighted contribution of each microRNA variation to the difference in outcome and identify outcome-specific networks. We then applied univariate models to the resulting microRNA variations common to both strategies, to interpret them as a function of demographic and clinical covariates.

STUDY RESULTS

We identified 207 microRNA variations that significantly contributed to the classification. The differential network analysis found 276 network-specific correlations of microRNA variations. The combination of both strategies identified 25 microRNAs, whose gene targets were overrepresented in cognition and schizophrenia genome-wide association studies findings. Interpretable univariate models further supported the relevance of miR-150-5p and miR-3191-5p variations in psychosis onset, independent of age, sex, cannabis use, and medication.

CONCLUSIONS

In this first longitudinal study of microRNA variation during conversion to psychosis, we combined 2 methodologically independent data-driven strategies to identify a dynamic epigenetic signature of the emergence of psychosis that is pathophysiologically relevant.

Epigenetic Regulation in Schizophrenia: Focus on Methylation and Histone Modifications in Human Studies

Despite extensive research over the last few decades, the etiology of schizophrenia (SZ) remains unclear. SZ is a pathological disorder that is highly debilitating and deeply affects the lifestyle and minds of those affected. Several factors (one or in combination) have been reported as contributors to SZ pathogenesis, including neurodevelopmental, environmental, genetic and epigenetic factors. Deoxyribonucleic acid (DNA) methylation and post-translational modification (PTM) of histone proteins are potentially contributing epigenetic processes involved in transcriptional activity, chromatin folding, cell division and apoptotic processes, and DNA damage and repair. After establishing a summary of epigenetic processes in the context of schizophrenia, this review aims to highlight the current understanding of the role of DNA methylation and histone PTMs in this disorder and their potential roles in schizophrenia pathophysiology and pathogenesis.

Precision psychiatry and Research Domain Criteria: Implications for clinical trials and future practice

Psychiatric disorders are associated with significant social and economic burdens, many of which are related to issues with current diagnosis and treatments. The coronavirus (COVID-19) pandemic is estimated to have increased the prevalence and burden of major depressive and anxiety disorders, indicating an urgent need to strengthen mental health systems globally. To date, current approaches adopted in drug discovery and development for psychiatric disorders have been relatively unsuccessful. Precision psychiatry aims to tailor healthcare more closely to the needs of individual patients and, when informed by neuroscience, can offer the opportunity to improve the accuracy of disease classification, treatment decisions, and prevention efforts. In this review, we highlight the growing global interest in precision psychiatry and the potential for the National Institute of Health-devised Research Domain Criteria (RDoC) to facilitate the implementation of transdiagnostic and improved treatment approaches. The need for current psychiatric nosology to evolve with recent scientific advancements and increase awareness in emerging investigators/clinicians of the value of this approach is essential. Finally, we examine current challenges and future opportunities of adopting the RDoC-associated translational and transdiagnostic approaches in clinical studies, acknowledging that the strength of RDoC is that they form a dynamic framework of guiding principles that is intended to evolve continuously with scientific developments into the future. A collaborative approach that recruits expertise from multiple disciplines, while also considering the patient perspective, is needed to pave the way for precision psychiatry that can improve the prognosis and quality of life of psychiatric patients.

The 3-hit animal models of schizophrenia: Improving strategy to decipher and treat the disease?

Schizophrenia is a complex disease related to combination and interactions between genetic and environmental factors, with an epigenetic influence. After the development of the first mono-factorial animal models of schizophrenia (1-hit), that reproduced patterns of either positive, negative and/or cognitive symptoms, more complex models combining two factors (2-hit) have been developed to better fit with the multifactorial etiology of the disease. In the two past decades, a new way to design animal models of schizophrenia have emerged by adding a third hit (3-hit). This review aims to discuss the relevance of the risk factors chosen for the tuning of the 3-hit animal models, as well as the validities measurements and their contribution to schizophrenia understanding. We intended to establish a comprehensive overview to help in the choice of factors for the design of multiple-hit animal models of schizophrenia.

The schizophrenia syndrome, circa 2024: What we know and how that informs its nature

With new data about different aspects of schizophrenia being continually generated, it becomes necessary to periodically revisit exactly what we know. Along with a need to review what we currently know about schizophrenia, there is an equal imperative to evaluate the construct itself. With these objectives, we undertook an iterative, multi-phase process involving fifty international experts in the field, with each step building on learnings from the prior one. This review assembles currently established findings about schizophrenia (construct, etiology, pathophysiology, clinical expression, treatment) and posits what they reveal about its nature. Schizophrenia is a heritable, complex, multi-dimensional syndrome with varying degrees of psychotic, negative, cognitive, mood, and motor manifestations. The illness exhibits a remitting and relapsing course, with varying degrees of recovery among affected individuals with most experiencing significant social and functional impairment. Genetic risk factors likely include thousands of common genetic variants that each have a small impact on an individual's risk and a plethora of rare gene variants that have a larger individual impact on risk. Their biological effects are concentrated in the brain and many of the same variants also increase the risk of other psychiatric disorders such as bipolar disorder, autism, and other neurodevelopmental conditions. Environmental risk factors include but are not limited to urban residence in childhood, migration, older paternal age at birth, cannabis use, childhood trauma, antenatal maternal infection, and perinatal hypoxia. Structural, functional, and neurochemical brain alterations implicate multiple regions and functional circuits. Dopamine D-2 receptor antagonists and partial agonists improve psychotic symptoms and reduce risk of relapse. Certain psychological and psychosocial interventions are beneficial. Early intervention can reduce treatment delay and improve outcomes. Schizophrenia is increasingly considered to be a heterogeneous syndrome and not a singular disease entity. There is no necessary or sufficient etiology, pathology, set of clinical features, or treatment that fully circumscribes this syndrome. A single, common pathophysiological pathway appears unlikely. The boundaries of schizophrenia remain fuzzy, suggesting the absence of a categorical fit and need to reconceptualize it as a broader, multi-dimensional and/or spectrum construct.

Divergent epigenetic responses to perinatal asphyxia in severe mental disorders

Epigenetic modifications influenced by environmental exposures are molecular sources of phenotypic heterogeneity found in schizophrenia and bipolar disorder and may contribute to shared etiopathogenetic mechanisms of these two disorders. Newborns who experienced perinatal asphyxia have suffered reduced oxygen delivery to the brain around the time of birth, which increases the risk of later psychiatric diagnosis. This study aimed to investigate DNA methylation in blood cells for associations with a history of perinatal asphyxia, a neurologically harmful condition occurring within the biological environment of birth. We utilized prospective data from the Medical Birth Registry of Norway to identify incidents of perinatal asphyxia in 643 individuals with schizophrenia or bipolar disorder and 676 healthy controls. We performed an epigenome wide association study to distinguish differentially methylated positions associated with perinatal asphyxia. We found an interaction between methylation and exposure to perinatal asphyxia on case-control status, wherein having a history of perinatal asphyxia was associated with an increase of methylation in healthy controls and a decrease of methylation in patients on 4 regions of DNA important for brain development and function. The differentially methylated regions were observed in genes involved in oligodendrocyte survival and axonal myelination and functional recovery (LINGO3); assembly, maturation and maintenance of the brain (BLCAP;NNAT and NANOS2) and axonal transport processes and neural plasticity (SLC2A14). These findings are consistent with the notion that an opposite epigenetic response to perinatal asphyxia, in patients compared with controls, may contribute to molecular mechanisms of risk for schizophrenia and bipolar disorder.

DNA methylation at birth and lateral ventricular volume in childhood: a neuroimaging epigenetics study

BACKGROUND

Lateral ventricular volume (LVV) enlargement has been repeatedly linked to schizophrenia; yet, what biological factors shape LVV during early development remain unclear. DNA methylation (DNAm), an essential process for neurodevelopment that is altered in schizophrenia, is a key molecular system of interest.

METHODS

In this study, we conducted the first epigenome-wide association study of neonatal DNAm in cord blood with LVV in childhood (measured using T1-weighted brain scans at 10 years), based on data from a large population-based birth cohort, the Generation R Study (N = 840). Employing both probe-level and methylation profile score (MPS) approaches, we further examined whether epigenetic modifications identified at birth in cord blood are: (a) also observed cross-sectionally in childhood using peripheral blood DNAm at age of 10 years (Generation R, N = 370) and (b) prospectively associated with LVV measured in young adulthood in an all-male sample from the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 114).

RESULTS

At birth, DNAm levels at four CpGs (annotated to potassium channel tetramerization domain containing 3, KCTD3; SHH signaling and ciliogenesis regulator, SDCCAG8; glutaredoxin, GLRX) prospectively associated with childhood LVV after genome-wide correction; these genes have been implicated in brain development and psychiatric traits including schizophrenia. An MPS capturing a broader epigenetic profile of LVV - but not individual top hits - showed significant cross-sectional associations with LVV in childhood in Generation R and prospectively associated with LVV in early adulthood within ALSPAC.

CONCLUSIONS

This study finds suggestive evidence that DNAm at birth prospectively associates with LVV at different life stages, albeit with small effect sizes. The prediction of MPS on LVV in a childhood sample and an independent male adult sample further underscores the stability and reproducibility of DNAm as a potential marker for LVV. Future studies with larger samples and comparable time points across development are needed to further elucidate how DNAm associates with this clinically relevant brain structure and risk for neuropsychiatric disorders, and what factors explain the identified DNAm profile of LVV at birth.

The impact of maternal immune activation on GABAergic interneuron development: A systematic review of rodent studies and their translational implications

Mothers exposed to infections during pregnancy disproportionally birth children who develop autism and schizophrenia, disorders associated with altered GABAergic function. The maternal immune activation (MIA) model recapitulates this risk factor, with many studies also reporting disruptions to GABAergic interneuron expression, protein, cellular density and function. However, it is unclear if there are species, sex, age, region, or GABAergic subtype specific vulnerabilities to MIA. Furthermore, to fully comprehend the impact of MIA on the GABAergic system a synthesised account of molecular, cellular, electrophysiological and behavioural findings was required. To this end we conducted a systematic review of GABAergic interneuron changes in the MIA model, focusing on the prefrontal cortex and hippocampus. We reviewed 102 articles that revealed robust changes in a number of GABAergic markers that present as gestationally-specific, region-specific and sometimes sex-specific. Disruptions to GABAergic markers coincided with distinct behavioural phenotypes, including memory, sensorimotor gating, anxiety, and sociability. Findings suggest the MIA model is a valid tool for testing novel therapeutics designed to recover GABAergic function and associated behaviour.

Captive ERVWE1 triggers impairment of 5-HT neuronal plasticity in the first-episode schizophrenia by post-transcriptional activation of HTR1B in ALKBH5-m6A dependent epigenetic mechanisms

BACKGROUND

Abnormalities in the 5-HT system and synaptic plasticity are hallmark features of schizophrenia. Previous studies suggest that the human endogenous retrovirus W family envelope (ERVWE1) is an influential risk factor for schizophrenia and inversely correlates with 5-HT4 receptor in schizophrenia. To our knowledge, no data describes the effect of ERVWE1 on 5-HT neuronal plasticity. N6-methyladenosine (m6A) regulates gene expression and impacts synaptic plasticity. Our research aims to systematically investigate the effects of ERVWE1 on 5-HT neuronal plasticity through m6A modification in schizophrenia.

RESULTS

HTR1B, ALKBH5, and Arc exhibited higher levels in individuals with first-episode schizophrenia compared to the controls and showed a strong positive correlation with ERVWE1. Interestingly, HTR1B was also correlated with ALKBH5 and Arc. Further analyses confirmed that ALKBH5 may be an independent risk factor for schizophrenia. In vitro studies, we discovered that ERVWE1 enhanced HTR1B expression, thereby activating the ERK-ELK1-Arc pathway and reducing the complexity and spine density of 5-HT neurons. Furthermore, ERVWE1 reduced m6A levels through ALKBH5 demethylation. ERVWE1 induced HTR1B upregulation by improving its mRNA stability in ALKBH5-m6A-dependent epigenetic mechanisms. Importantly, ALKBH5 mediated the observed alterations in 5-HT neuronal plasticity induced by ERVWE1.

CONCLUSIONS

Overall, HTR1B, Arc, and ALKBH5 levels were increased in schizophrenia and positively associated with ERVWE1. Moreover, ALKBH5 was a novel risk gene for schizophrenia. ERVWE1 impaired 5-HT neuronal plasticity in ALKBH5-m6A dependent mechanism by the HTR1B-ERK-ELK1-Arc pathway, which may be an important contributor to aberrant synaptic plasticity in schizophrenia.

DNA methylation and the opposing NMDAR dysfunction in schizophrenia and major depression disorders: a converging model for the therapeutic effects of psychedelic compounds in the treatment of psychiatric illness

Psychedelic compounds are being increasingly explored as a potential therapeutic option for treating several psychiatric conditions, despite relatively little being known about their mechanism of action. One such possible mechanism, DNA methylation, is a process of epigenetic regulation that changes gene expression via chemical modification of nitrogenous bases. DNA methylation has been implicated in the pathophysiology of several psychiatric conditions, including schizophrenia (SZ) and major depressive disorder (MDD). In this review, we propose alterations to DNA methylation as a converging model for the therapeutic effects of psychedelic compounds, highlighting the N-methyl D-aspartate receptor (NMDAR), a crucial mediator of synaptic plasticity with known dysfunction in both diseases, as an example and anchoring point. We review the established evidence relating aberrant DNA methylation to NMDAR dysfunction in SZ and MDD and provide a model asserting that psychedelic substances may act through an epigenetic mechanism to provide therapeutic effects in the context of these disorders.

Genome-wide DNA methylation analysis in families with multiple individuals diagnosed with schizophrenia and intellectual disability

OBJECTIVES

Schizophrenia (SZ) and intellectual disability (ID) are both included in the continuum of neurodevelopmental disorders (NDDs). DNA methylation is known to be important in the occurrence of NDDs. The family study is conducive to eliminate the effects of relative epigenetic backgrounds, and to screen for differentially methylated positions (DMPs) and regions (DMRs) that are truly associated with NDDs.

METHODS

Four monozygotic twin families were recruited, and both twin individuals suffered from NDDs (either SZ, ID, or SZ plus ID). Genome-wide methylation analysis was performed in all samples and each family. DMPs and DMRs between NDD patients and unaffected individuals were identified. Functional and pathway enrichment analyses were performed on the annotated genes.

RESULTS

Two significant DMPs annotated to CYP2E1 were found in all samples. In Family One, 1476 DMPs mapped to 880 genes, and 162 DMRs overlapping with 153 unique genes were recognised. Our results suggested that the altered methylation levels of FYN, STAT3, RAC1, and NR4A2 were associated with the development of SZ and ID. Neurodevelopment and the immune system may participate in the occurrence of SZ and ID.

CONCLUSIONS

Our findings suggested that DNA methylation participated in the development of NDDs by affecting neurodevelopment and the immune system.

Nissl Granules, Axonal Regeneration, and Regenerative Therapeutics: A Comprehensive Review

Nissl granules, traditionally recognized for their pivotal role in protein synthesis within neuronal cell bodies, are emerging as intriguing components with far-reaching implications in the realm of regenerative therapeutics. This abstract encapsulates the essence of a comprehensive review, exploring the nexus between Nissl granules, axonal regeneration, and their transformative applications in regenerative medicine. The molecular intricacies of Nissl granules form the foundation of this exploration, unraveling their dynamic role in orchestrating cellular responses, particularly in the context of axonal regeneration. As we delve into the interplay between Nissl granules and regenerative processes, this review highlights the diverse mechanisms through which these granules contribute to neuronal repair and recovery. Beyond their conventional association with neurobiology, recent advancements underscore the translational potential of Nissl granules as therapeutic agents. Insights into their involvement in enhancing axonal regeneration prompt a reconsideration of these granules as key players in the broader field of regenerative medicine. The abstract encapsulates evidence suggesting that modulating Nissl granule-related pathways holds promise for augmenting tissue regeneration, extending their applicability beyond the confines of the nervous system. This review aims to serve as a valuable resource for medical professionals, researchers, and clinicians seeking to comprehend the multifaceted role of Nissl granules in regenerative therapeutics. By illuminating the intricate connections between Nissl granules, axonal regeneration, and therapeutic applications, this work aspires to catalyze further research and innovation, ultimately contributing to the evolution of regenerative strategies that harness the innate reparative capacities within cellular constituents.

Correlations between schizophrenia and lichen planus: a two-sample bidirectional Mendelian randomization study

Background

Several existing studies have shown a correlation between schizophrenia and lichen planus (LP). However, the causality of this relationship remains uncertain. Thus, this study aimed to examine the causal association between schizophrenia and LP.

Methods

A two-sample Mendelian randomization (MR) study was carried out to investigate whether schizophrenia is causally related to LP and vice versa, and genetic variants in this study were taken from previous genome-wide association studies. We used the inverse variance weighted (IVW) method as the main analysis. Furthermore, several sensitivity analyses were performed to assess heterogeneity, horizontal pleiotropy, and stability.

Results

Our results show that schizophrenia has a protective effect on LP (OR = 0.881, 95%CI = 0.795-0.975, p = 0.015). Conversely, we observed no significant relationship between LP and schizophrenia in reverse MR analysis (OR = 0.934, 95%CI = 0.851-1.026, p = 0.156).

Conclusion

Our two-sample Mendelian randomization study supports a significant causal relationship between LP and schizophrenia and finds that schizophrenia can reduce the incidence of LP. This is in contrast to previous findings and provides new insights into the relationship between LP and schizophrenia, but the exact mechanism needs further investigation.

Upregulation of HDAC9 in hippocampal neurons mediates depression-like behaviours by inhibiting ANXA2 degradation

Major depressive disorder (MDD) is a pervasive and devastating mental disease. Broad spectrum histone deacetylase (HDAC) inhibitors are considered to have potential for the treatment of depressive phenotype in mice. However, due to its non-specific inhibition, it has extensive side effects and can not be used in clinical treatment of MDD. Therefore, finding specific HDAC subtypes that play a major role in the etiology of MDD is the key to develop corresponding specific inhibitors as antidepressants in the future. Copy number variation in HDAC9 gene is thought to be associated with the etiology of some psychiatric disorders. Herein, we found that HDAC9 was highly expressed in the hippocampus of chronic restraint stress (CRS) mouse model of depression. Upregulation of HDAC9 expression in hippocampal neurons of mice induced depression-like phenotypes, including anhedonia, helplessness, decreased dendritic spine density, and neuronal hypoexcitability. Moreover, knockdown or knockout of HDAC9 in hippocampal neurons alleviated depression-like phenotypes caused by chronic restraint stress (CRS) in WT mice. Importantly, using immunoprecipitation-mass spectrometry (IP-MS), we further found that Annexin A2 (ANXA2) was coupled to and deacetylated by HDAC9. This coupling resulted in the inhibition of ubiquitinated ANXA2 degradation and then mediates depression-like behavior. Overall, we discovered a previously unrecognized role for HDAC9 in hippocampal neurons in the pathogenesis of depression, indicating that inhibition of HDAC9 might be a promising clinical strategy for the treatment of depressive disorders.

Diversity and Chemical Space Characterization of Inhibitors of the Epigenetic Target G9a: A Chemoinformatics Approach

G9a is a histone-lysine methyltransferase that performs the mono- and dimethylation of lysine 9 at histone 3 of the nucleosome. It belongs to the SET PKMT family, and its methylations are related to promoter repression and activation. G9a is a promising epigenetic target. Despite the fact that there are several G9a inhibitors under development, there are no compounds in clinical use due to adverse in vivo ADMET (absorption, distribution, metabolism, excretion, and toxicity) issues. The goal of this study is to discuss the exploration, characterization, and analysis of the chemical space of 409 G9a inhibitors reported in a large public database. Exploring the chemical space of the inhibitors led to the quantification of their structural diversity based on molecular scaffolds and structural fingerprints of different designs. As part of the analysis, the G9a inhibitors were compared with commercial libraries focused on epigenetic targets. The findings of this work will help in the development of, in a follow-up study, predictive models to identify G9a inhibitors. This study also points out the relevance of screening commercial libraries to expand the epigenetic relevant chemical space, in particular, G9a inhibitors.

YBX1-Mediated DNA Methylation-Dependent SHANK3 Expression in PBMCs and Developing Cortical Interneurons in Schizophrenia

Schizophrenia (SCZ) is a severe psychiatric and neurodevelopmental disorder. The pathological process of SCZ starts early during development, way before the first onset of psychotic symptoms. DNA methylation plays an important role in regulating gene expression and dysregulated DNA methylation is involved in the pathogenesis of various diseases. The methylated DNA immunoprecipitation-chip (MeDIP-chip) is performed to investigate genome-wide DNA methylation dysregulation in peripheral blood mononuclear cells (PBMCs) of patients with first-episode SCZ (FES). Results show that the SHANK3 promoter is hypermethylated, and this hypermethylation (HyperM) is negatively correlated with the cortical surface area in the left inferior temporal cortex and positively correlated with the negative symptom subscores in FES. The transcription factor YBX1 is further found to bind to the HyperM region of SHANK3 promoter in induced pluripotent stem cells (iPSCs)-derived cortical interneurons (cINs) but not glutamatergic neurons. Furthermore, a direct and positive regulatory effect of YBX1 on the expression of SHANK3 is confirmed in cINs using shRNAs. In summary, the dysregulated SHANK3 expression in cINs suggests the potential role of DNA methylation in the neuropathological mechanism underlying SCZ. The results also suggest that HyperM of SHANK3 in PBMCs can serve as a potential peripheral biomarker of SCZ.

Inflammatory disequilibrium and lateral ventricular enlargement in treatment-resistant schizophrenia

Treatment-resistant schizophrenia (TRS) patient respond poorly to antipsychotics. Inflammatory imbalance involving pro- and anti-inflammatory cytokines may play an important role in the mechanism of antipsychotic-medication response. This study aimed to investigate immune imbalance and how the latter relates to clinical manifestations in patients with TRS. The level of net inflammation was estimated by evaluating the immune-inflammatory response system and compensatory immune-regulatory reflex system (IRS/CIRS) in 52 patients with TRS, 47 with non-TRS, and 56 sex and age matched healthy controls. The immune biomarkers mainly included macrophagic M1, T helper, Th-1, Th-2, Th-17, and T regulatory cytokines and receptors. Plasma cytokine levels were measured using enzyme-linked immunosorbent assay. Psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). Subcortical volumes were quantified using a 3-T Prisma Magnetic Resonance Imaging scanner. The results showed that (1) patients with TRS were characterized by activated pro-inflammatory cytokines and relatively insufficient anti-inflammatory cytokines, with an elevated IRS/CIRS ratio indicating a new homeostatic immune setpoint; (2) IRS/CIRS ratio was positively correlated with larger lateral ventricle volume and higher PANSS score in patients with TRS. Our findings highlighted the inflammatory disequilibrium as a potential pathophysiological process of TRS.

Association of Peripheral Inflammatory Biomarkers and Growth Factors Levels with Sex, Therapy and Other Clinical Factors in Schizophrenia and Patient Stratification Based on These Data

Multiple lines of evidence are known to confirm the pro-inflammatory state of some patients with schizophrenia and the involvement of inflammatory mechanisms in the pathogenesis of psychosis. The concentration of peripheral biomarkers is associated with the severity of inflammation and can be used for patient stratification. Here, we analyzed changes in serum concentrations of cytokines (IL-1β, IL-2, IL-4, IL-6, IL-10, IL-21, APRIL, BAFF, PBEF/Visfatin, IFN-α, and TNF-α) and growth/neurotrophic factors (GM-CSF, NRG1-β1, NGF-β, and GDNF) in patients with schizophrenia in an exacerbation phase. IL-1β, IL-2, IL-4, IL-6, BAFF, IFN-α, GM-CSF, NRG1-β1, and GDNF increased but TNF-α and NGF-β decreased in schizophrenia compared to healthy individuals. Subgroup analysis revealed the effect of sex, prevalent symptoms, and type of antipsychotic therapy on biomarker levels. Females, patients with predominantly negative symptoms, and those taking atypical antipsychotics had a more pro-inflammatory phenotype. Using cluster analysis, we classified participants into "high" and "low inflammation" subgroups. However, no differences were found in the clinical data of patients in these subgroups. Nevertheless, more patients (17% to 25.5%) than healthy donors (8.6% to 14.3%) had evidence of a pro-inflammatory condition depending on the clustering approach used. Such patients may benefit from personalized anti-inflammatory therapy.

Study on clinical characteristics of event-related potential P300 in elderly schizophrenics and associated risk factors

OBJECTIVE

To investigate the clinical characteristics of event-related potential P300 in elderly schizophrenics with different levels of violence and the risk factors of severe violence.

METHODS

A total of 138 elderly schizophrenic patients from January 2020 to December 2021 in the First Hospital of Hebei Medical University were enrolled in this retrospective analysis. Based on the violence risk assessment, 61, 102, and 145 patients were divided into high-risk, medium-risk, and low-risk groups, respectively. Clinical characteristics, P300 latency, and P300 amplitude were compared among the three groups followed by a logistic regression analysis of elderly schizophrenics with severe violence.

RESULTS

The latency of P300 in the high-risk group was higher than that in the low-risk group (p < .05). The P300 amplitude of patients in the high-risk group was significantly lower than that in the low-risk group (p < .05). Univariate logistic regression analysis showed that previous history of violence, delusion of persecution, P300 latency, and amplitude were independent influencing factors of severe violence in elderly schizophrenics (odds ratio [OR]: 0.022, 95% confidence interval [CI]: 0.007-0.067, p < .001; OR: 0.118, 95% CI: 0.043-1.763, p = .037; OR: 1.289, 95% CI: 1.142-1.673, p < .001; and OR: 0.049, 95% CI: 0.021-0.067, p < 0.001, respectively). After adjusting gender, age, and other confounding factors, multivariate logistic regression analysis showed that delusion of persecution, P300 latency, and P300 amplitude were associated with severe violence in elderly schizophrenics (OR: 2.211, 95% CI: 0.061-4.067, p < .001; OR: 2.006, 95% CI: 1.421-2.721, p = .017; and OR: 0.067, 95% CI: 0.037-0.276; p < .001; respectively).

CONCLUSION

The latency and amplitude of P300 can be used as effective neuroelectrophysiological indicators to evaluate the violence level of elderly schizophrenics. Delusion of persecution, P300 latency, and P300 amplitude were independent influencing factors of severe violence in elderly schizophrenics.

The adenosine hypothesis of schizophrenia into its third decade: From neurochemical imbalance to early life etiological risks

The adenosine hypothesis of schizophrenia was conceptualized about two decades ago in an attempt to integrate two prominent theories of neurochemical imbalance that attribute the pathogenesis of schizophrenia to hyperfunction of the mesocorticolimbic dopamine neurotransmission and hypofunction of cortical glutamate neurotransmission. Given its unique position as an endogenous modulator of both dopamine and glutamate signaling in the brain, adenosine was postulated as a potential new drug target to achieve multiple antipsychotic actions. This new strategy may offer hope for improving treatment, especially in alleviating negative symptoms and cognitive deficits of schizophrenia that do not respond to current medications. To date, however, the adenosine hypothesis has yet led to any significant therapeutic breakthroughs. Here, we address two possible reasons for the impasse. First, neither the presence of adenosine functional deficiency in people with schizophrenia nor its causal relationship to symptom production has been satisfactorily examined. Second, the lack of novel adenosine-based drugs also impedes progress. This review updates the latest preclinical and clinical data pertinent to the construct validity of the adenosine hypothesis and explores novel molecular processes whereby dysregulation of adenosine signaling could be linked to the etiology of schizophrenia. It is intended to stimulate and revitalize research into the adenosine hypothesis towards the development of a new and improved generation of antipsychotic drugs that has eluded us for decades.

Restoring the missing person to personalized medicine and precision psychiatry

Precision psychiatry has emerged as part of the shift to personalized medicine and builds on frameworks such as the U.S. National Institute of Mental Health Research Domain Criteria (RDoC), multilevel biological "omics" data and, most recently, computational psychiatry. The shift is prompted by the realization that a one-size-fits all approach is inadequate to guide clinical care because people differ in ways that are not captured by broad diagnostic categories. One of the first steps in developing this personalized approach to treatment was the use of genetic markers to guide pharmacotherapeutics based on predictions of pharmacological response or non-response, and the potential risk of adverse drug reactions. Advances in technology have made a greater degree of specificity or precision potentially more attainable. To date, however, the search for precision has largely focused on biological parameters. Psychiatric disorders involve multi-level dynamics that require measures of phenomenological, psychological, behavioral, social structural, and cultural dimensions. This points to the need to develop more fine-grained analyses of experience, self-construal, illness narratives, interpersonal interactional dynamics, and social contexts and determinants of health. In this paper, we review the limitations of precision psychiatry arguing that it cannot reach its goal if it does not include core elements of the processes that give rise to psychopathological states, which include the agency and experience of the person. Drawing from contemporary systems biology, social epidemiology, developmental psychology, and cognitive science, we propose a cultural-ecosocial approach to integrating precision psychiatry with person-centered care.

Virtual histology of morphometric similarity network after risperidone monotherapy and imaging-epigenetic biomarkers for treatment response in first-episode schizophrenia

BACKGROUND

Antipsychotic treatment has been conceived to alter brain connectivity, but it is unclear how the changes of network phenotypes relate to the underlying transcriptomics. Given DNA methylation (DNAm) may alter transcriptional levels, we further integrated an imaging-transcriptomic-epigenetic analysis to explore multi-omics treatment response biomarkers.

METHODS

Forty-two treatment-naive first-episode schizophrenia patients were scanned by TI weighted (T1W) imaging and DTI before and after 8-week risperidone monotherapy, and their peripheral blood genomic DNAm values were examined in parallel with MRI scanning. Morphometric similarity network (MSN) quantified with DTI and T1W data were used as a marker of treatment-related alterations in interareal cortical connectivity. We utilized partial least squares (PLS) to examine spatial associations between treatment-related MSN variations and cortical transcriptomic data obtained from the Allen Human Brain Atlas.

RESULTS

Longitudinal MSN alterations were related to treatment response on cognitive function and general psychopathology symptoms, while DNAm values of 59 PLS1 genes were on negative and positive symptoms. Virtual-histology transcriptomic analysis linked the MSN alterations with the neurobiological, cellular and metabolic pathways or processes, and assigned MSN-related genes to multiple cell types, specifying neurons and glial cells as contributing most to the transcriptomic associations of longitudinal changes in MSN.

CONCLUSIONS

We firstly reveal how brain-wide transcriptional levels and cell classes capture molecularly validated cortical connectivity alterations after antipsychotic treatment. Our findings represent a vital step towards the exploration of treatment response biomarkers on the basis of multiple omics rather than a single omics type as a strategy for advancing precise care.

Biological hypotheses, risk factors, and biomarkers of schizophrenia

Both the discovery of biomarkers of schizophrenia and the verification of biological hypotheses of schizophrenia are an essential part of the process of understanding the etiology of this mental disorder. Schizophrenia has long been considered a neurodevelopmental disease whose symptoms are caused by impaired synaptic signal transduction and brain neuroplasticity. Both the onset and chronic course of schizophrenia are associated with risk factors-induced disruption of brain function and the establishment of a new homeostatic setpoint characterized by biomarkers. Different risk factors and biomarkers can converge to the same symptoms of schizophrenia, suggesting that the primary cause of the disease can be highly individual. Schizophrenia-related biomarkers include measurable biochemical changes induced by stress (elevated allostatic load), mitochondrial dysfunction, neuroinflammation, oxidative and nitrosative stress, and circadian rhythm disturbances. Here is a summary of selected valid biological hypotheses of schizophrenia formulated based on risk factors and biomarkers, neurodevelopment, neuroplasticity, brain chemistry, and antipsychotic medication. The integrative neurodevelopmental-vulnerability-neurochemical model is based on current knowledge of the neurobiology of the onset and progression of the disease and the effects of antipsychotics and psychotomimetics and reflects the complex and multifactorial nature of schizophrenia.

Genomic regulatory sequences in the pathogenesis of bipolar disorder

The lifetime prevalence of bipolar disorder is estimated to be about 2%. Epigenetics defines regulatory mechanisms that determine relatively stable patterns of gene expression by controlling all key steps, from DNA to messenger RNA to protein. This Mini Review highlights recent discoveries of modified epigenetic control resulting from genetic variants associated with bipolar disorder in genome-wide association studies. The revealed epigenetic abnormalities implicate gene transcription and post-transcriptional regulation. In the light of these discoveries, the Mini Review focuses on the genes PACS1, MCHR1, DCLK3, HAPLN4, LMAN2L, TMEM258, GNL3, LRRC57, CACNA1C, CACNA1D, and NOVA2 and their potential biological role in the pathogenesis of bipolar disorder. Molecular mechanisms under control of these genes do not translate into a unified picture and substantially more research is needed to fill the gaps in knowledge and to solve current limitations in prognosis and treatment of bipolar disorder. In conclusion, the genetic and functional studies confirm the complex nature of bipolar disorder and indicate future research directions to explore possible targeted treatment options, eventually working toward a personalized approach.

Epigenetic clocks in relapse after a first episode of schizophrenia

The main objective of the present study was to investigate the association between several epigenetic clocks, covering different aspects of aging, with schizophrenia relapse evaluated over a 3-year follow-up period in a cohort of ninety-one first-episode schizophrenia patients. Genome-wide DNA methylation was profiled and four epigenetic clocks, including epigenetic clocks of chronological age, mortality and telomere length were calculated. Patients that relapsed during the follow-up showed epigenetic acceleration of the telomere length clock (p = 0.030). Shorter telomere length was associated with cognitive performance (working memory, r = 0.31 p = 0.015; verbal fluency, r = 0.28 p = 0.028), but no direct effect of cognitive function or symptom severity on relapse was detected. The results of the present study suggest that epigenetic age acceleration could be involved in the clinical course of schizophrenia and could be a useful marker of relapse when measured in remission stages.

Current progress in understanding schizophrenia using genomics and pluripotent stem cells: A meta-analytical overview

Schizophrenia (SCZ) is a complex, heritable and polygenic neuropsychiatric disease, which disables the patients as well as decreases their life expectancy and quality of life. Common and rare variants studies on SCZ subjects have provided >100 genomic loci that hold importance in the context of SCZ pathophysiology. Transcriptomic studies from clinical samples have informed about the differentially expressed genes (DEGs) and non-coding RNAs in SCZ patients. Despite these advancements, no causative genes for SCZ were found and hence SCZ is difficult to recapitulate in animal models. In the last decade, induced Pluripotent Stem Cells (iPSCs)-based models have helped in understanding the neural phenotypes of SCZ by studying patient iPSC-derived 2D neuronal cultures and 3D brain organoids. Here, we have aimed to provide a simplistic overview of the current progress and advancements after synthesizing the enormous literature on SCZ genetics and SCZ iPSC-based models. Although further understanding of SCZ genetics and pathophysiological mechanisms using these technological advancements is required, the recent approaches have allowed to delineate important cellular mechanisms and biological pathways affected in SCZ.

Altered expression levels of miR-144-3p and ATP1B2 are associated with schizophrenia

Objectives: Schizophrenia is a devastating mental disease. Various microRNAs were proven to be associated with schizophrenia. Altered microRNA-144-3p (miR-144-3p) levels were found in various neurological and psychotic disorders. Beta2-subunit of Na(+)/K(+)-ATPase (ATP1B2) regulates neuronal migration and cell growth during brain development through the PI3K/Akt/mTOR pathway. The present study explored the associations of miR-144-3p and ATP1B2 with schizophrenia and their mutual interaction.Methods: A schizophrenic animal model employing repeated MK-801 administration was established and 293 T cells over-expressing miR-144-3p were constructed by lentivirus. The in vitro and in vivo levels of miR-144-3p, ATP1B2, and the PI3K/Akt/mTOR pathway were examined by qRT-PCR and Western Blots. The interaction between miR-144-3p and ATP1B2 was predicted and assessed by using bioinformatic methods and a luciferase reporter gene assay, respectively.Results: MiR-144-3p expression was elevated in the schizophrenic rat hippocampus. ATP1B2 was down-regulated in schizophrenic patients by analysing GEO datasets. Additionally, miR-144-3p can directly bind with ATP1B2. Furthermore, the ATP1B2 expression and PI3K/Akt/mTOR phosphorylation levels were down-regulated in the 293 T cells over-expressing miR-144-3p and schizophrenic rat hippocampus, which could be reversed by risperidone.Conclusions: This study revealed that up-regulated miR-144-3p might be associated with schizophrenia through down-regulating ATP1B2, implicating new targets of schizophrenia treatment.

Sources and Translational Relevance of Heterogeneity in Maternal Immune Activation Models

The epidemiological literature reporting increased risk for neurodevelopmental and psychiatric disorders after prenatal exposure to maternal immune activation (MIA) is still evolving, and so are the attempts to model this association in animals. Epidemiological studies of MIA offer the advantage of directly evaluating human populations but are often limited in their ability to uncover pathogenic mechanisms. Animal models, on the other hand, are limited in their generalizability to psychiatric disorders but have made significant strides toward discovering causal relationships and biological pathways between MIA and neurobiological phenotypes. Like in any other model system, both planned and unplanned sources of variability exist in animal models of MIA. Therefore, the design, implementation, and interpretation of MIA models warrant a careful consideration of these sources, so that appropriate strategies can be developed to handle them satisfactorily. While every research group may have its own strategy to this aim, it is essential to report the methodological details of the chosen MIA model in order to enhance the transparency and comparability of models across research laboratories. Even though it poses a challenge for attempts to compare experimental findings across laboratories, variability does not undermine the utility of MIA models for translational research. In fact, variability and heterogenous outcomes in MIA models offer unique opportunities for new discoveries and developments in this field, including the identification of disease pathways and molecular mechanisms determining susceptibility and resilience to MIA. This review summarizes the most important sources of variability in animal models of MIA and discusses how model variability can be used to investigate neurobiological and immunological factors causing phenotypic heterogeneity in offspring exposed to MIA.

Interactions between dopamine transporter and N-methyl-d-aspartate receptor-related amino acids on cognitive impairments in schizophrenia

BACKGROUND

Cognitive impairments, the main determinants of functional outcomes in schizophrenia, had limited treatment responses and need a better understanding of the mechanisms. Dysfunctions of the dopamine system and N-methyl-d-aspartate receptor (NMDAR), the primary pathophysiologies of schizophrenia, may impair cognition. This study explored the effects and interactions of striatal dopamine transporter (DAT) and plasma NMDAR-related amino acids on cognitive impairments in schizophrenia.

METHODS

We recruited 36 schizophrenia patients and 36 age- and sex-matched healthy controls (HC). All participants underwent cognitive assessments of attention, memory, and executive function. Single-photon emission computed tomography with 99mTc-TRODAT and ultra-performance liquid chromatography were applied to determine DAT availability and plasma concentrations of eight amino acids, respectively.

RESULTS

Compared with HC, schizophrenia patients had lower cognitive performance, higher methionine concentrations, decreased concentrations of glutamic acid, cysteine, aspartic acid, arginine, the ratio of glutamic acid to gamma-aminobutyric acid (Glu/GABA), and DAT availability in the left caudate nucleus (CN) and putamen. Regarding memory scores, Glu/GABA and the DAT availability in left CN and putamen exhibited positive relationships, while methionine concentrations showed negative associations in all participants. The DAT availability in left CN mediated the methionine-memory relationship. An exploratory backward stepwise regression analysis for the four biological markers associated with memory indicated that DAT availability in left CN and Glu/GABA remained in the final model.

CONCLUSIONS

This study demonstrated the interactions of striatal DAT and NMDAR-related amino acids on cognitive impairments in schizophrenia. Future studies to comprehensively evaluate their complex interactions and treatment implications are warranted.

Patient-Derived In Vitro Models of Microglial Function and Synaptic Engulfment in Schizophrenia

Multiple lines of evidence implicate dysregulated microglia-mediated synaptic pruning in the pathophysiology of schizophrenia. In vitro human cellular studies represent a promising means of pursuing this hypothesis, complementing efforts with animal models and postmortem human data while addressing their limitations. The challenges in culturing homogeneous populations of cells derived from postmortem or surgical biopsy brain material from patients, and their limited availability, has led to a focus on differentiation of induced pluripotent stem cells. These methods too have limitations, in that they disrupt the epigenome and can demonstrate line-to-line variability due in part to extended time in culture, partial reprogramming, and/or residual epigenetic memory from the cell source, yielding large technical artifacts. Yet another strategy uses direct transdifferentiation of peripheral mononuclear blood cells, or umbilical cord blood cells, to microglia-like cells. Any of these approaches can be paired with patient-derived synaptosomes from differentiated neurons as a simpler alternative to co-culture. Patient-derived microglia models may facilitate identification of novel modulators of synaptic pruning and identification of biomarkers that may allow more targeted early interventions.

Schizophrenia-derived hiPSC brain microvascular endothelial-like cells show impairments in angiogenesis and blood-brain barrier function

Schizophrenia (SZ) is a complex neuropsychiatric disorder, affecting 1% of the world population. Long-standing clinical observations and molecular data have pointed to a possible vascular deficiency that could be acting synergistically with neuronal dysfunction in SZ. As SZ is a neurodevelopmental disease, the use of human-induced pluripotent stem cells (hiPSC) allows disease biology modeling while retaining the patient's unique genetic signature. Previously, we reported a VEGFA signaling impairment in SZ-hiPSC-derived neural lineages leading to decreased angiogenesis. Here, we present a functional characterization of SZ-derived brain microvascular endothelial-like cells (BEC), the counterpart of the neurovascular crosstalk, revealing an intrinsically defective blood-brain barrier (BBB) phenotype. Transcriptomic assessment of genes related to endothelial function among three control (Ctrl BEC) and five schizophrenia patients derived BEC (SZP BEC), revealed that SZP BEC have a distinctive expression pattern of angiogenic and BBB-associated genes. Functionally, SZP BEC showed a decreased angiogenic response in vitro and higher transpermeability than Ctrl BEC. Immunofluorescence staining revealed less expression and altered distribution of tight junction proteins in SZP BEC. Moreover, SZP BEC's conditioned media reduced barrier capacities in the brain microvascular endothelial cell line HCMEC/D3 and in an in vivo permeability assay in mice. Overall, our results describe an intrinsic failure of SZP BEC for proper barrier function. These findings are consistent with the hypothesis tracing schizophrenia origins to brain development and BBB dysfunction.

A New Treatment Paradigm: Targeting Trace Amine-Associated Receptor 1 (TAAR1) in Schizophrenia

This continuing education supplement is jointly provided by Medical Education Resources and CMEology. The supplement is supported by an independent educational grant from Sunovion Pharmaceuticals Inc. It was edited and peer reviewed by the Journal of Clinical Psychopharmacology.After reviewing the learning objectives and reading the supplement, please complete the Activity Evaluation/Credit Request form online at https://www.cmesurvey.site/TAAR1.

ABSTRACT

All currently available antipsychotics work via essentially the same mechanism: by antagonizing the dopamine D2 receptor. However, schizophrenia is an extremely heterogeneous condition, and antipsychotics do not adequately control symptoms for all patients. Negative and cognitive symptoms are especially difficult to manage with existing medications. Therefore, antipsychotic agents with novel mechanisms of action are urgently needed. Recently, a phase 2 clinical trial and extension study demonstrated that, relative to placebo, the trace amine-associated receptor 1 (TAAR1) agonist ulotaront was effective at controlling the positive, negative, and cognitive symptoms of schizophrenia. In addition, ulotaront seems to lack the weight gain, metabolic issues, and extrapyramidal symptoms associated with traditional antipsychotics. This agent is currently undergoing multiple phase 3 trials for the treatment of schizophrenia. Another TAAR1 agonist, ralmitaront, is being investigated for the treatment of schizophrenia and schizoaffective disorders. Two phase 2 clinical trials are underway, evaluating ralmitaront both as a monotherapy and an add-on therapy to traditional antipsychotics. In this supplement, we review the biologic, preclinical, and clinical data available for TAAR1 agonists, so that if and when they are approved for the treatment of schizophrenia, psychiatry specialists will be ready to use them to optimize patient outcomes. We also briefly review other emerging therapies in late-stage development for the treatment of schizophrenia.

The impact of COVID-19 pandemic on individuals at clinical high-risk for psychosis: Evidence from eye-tracking measures

Emerging evidence suggested that people with severe mental disorders were more vulnerable to the negative effects of the COVID-19 pandemic. However, few researches investigated the influence of global pandemics on people at clinical high risk (CHR) for psychosis. This study aimed to investigate the impact of the COVID-19 pandemic on clinical symptoms, psychological distress, and eye-tracking characteristics in CHR individuals and healthy participants. Forty-nine CHR individuals and 50 healthy controls (HC) were assessed by PTSD Checklist for DSM-5 (PCL-5), Perceived Stress Scale, 10-item version (PSS-10), and Coronavirus Impact Scale (CIS). Eye movement performances were measured by the tests of fixation stability, free-viewing, and anti-saccade. According to the mean score of CIS, participants were stratified into high-impact (n = 35) and low-impact (n = 64) subgroups. Compared with the HC group, CHR participants reported significantly higher levels of post-traumatic symptoms caused by the COVID-19 pandemic and showed abnormalities in most of the eye movement indexes. Among the altered indexes, the saccade amplitude of fixation stability test (far distractor), the scan path length of free-viewing test, and the accuracy of anti-saccade test were negatively affected by the severity of impact level in the CHR group. Moreover, the altered eye movement indexes were significantly associated with the total scores of CIS, PCL-5, and subscales of the Scale of Prodromal Syndromes (SOPS) among CHR individuals. Overall, our findings suggested the negative impact of the COVID-19 pandemic on the eye movement characteristics of CHR individuals. The present study provides valuable information on physiological distress related to the COVID-19 pandemic and sensitive neuropsychological biomarkers that interacted with social and environment stress in the CHR population.

Evaluation of mRNA expression level of the ATP synthase membrane subunit c locus 1 (ATP5G1) gene in patients with schizophrenia

Background

Schizophrenia is a serious, complex mental disorder. The impairment of oxidative phosphorylation has a detrimental consequence on CNS function. Different ATP synthase subunits have been involved in the pathological process of various neurodegenerative disorders. Our goal was to evaluate the mRNA expression level of the ATP synthase membrane subunit c locus 1 (ATP5G1, also named ATP5MC1) gene in patients with schizophrenia.

Methods

Determination of the expression levels of ATP5G1 in plasma and peripheral blood mononuclear cells (PBMCs) were performed by real-time PCR in 90 controls and 90 patients with schizophrenia.

Results

Patients had significantly decreased ATP5G1 mRNA expression levels in both plasma and PBMCs compared to controls. The receiver operating characteristic curve was applied to detect a cut-off value of ATP5G1 expression in plasma and PBMCs. The ATP5G1 relative expression in PBMCs had better performance with a cut-off value ≤ 21 (AUC = 0.892, P < 0.001), sensitivity of 94.44%, and specificity of 72.22% in discriminating between schizophrenic patients. ATP5G1 expression in PBMCs was an independent predictor in schizophrenia.

Conclusion

This study revealed a down-regulation of ATP5G1 expression in schizophrenia, precisely expression in PBMCs. That might give insight into the role of ATP5G1 gene in the pathogenesis of schizophrenia.

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This study revealed a down-regulation of ATP5G1 expression in schizophrenia, precisely expression in PBMCs, which was found as an independent risk factor.

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This might give insight into the role of the ATP5G1 gene in the pathogenesis of schizophrenia.

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Further studies are needed to evaluate the role of ATP5G1 in schizophrenia and their impact on ATP production in these patients.

Crosstalk between Schizophrenia and Metabolic Syndrome: The Role of Oxytocinergic Dysfunction

The high prevalence of metabolic syndrome in persons with schizophrenia has spurred investigational efforts to study the mechanism beneath its pathophysiology. Early psychosis dysfunction is present across multiple organ systems. On this account, schizophrenia may be a multisystem disorder in which one organ system is predominantly affected and where other organ systems are also concurrently involved. Growing evidence of the overlapping neurobiological profiles of metabolic risk factors and psychiatric symptoms, such as an association with cognitive dysfunction, altered autonomic nervous system regulation, desynchrony in the resting-state default mode network, and shared genetic liability, suggest that metabolic syndrome and schizophrenia are connected via common pathways that are central to schizophrenia pathogenesis, which may be underpinned by oxytocin system dysfunction. Oxytocin, a hormone that involves in the mechanisms of food intake and metabolic homeostasis, may partly explain this piece of the puzzle in the mechanism underlying this association. Given its prosocial and anorexigenic properties, oxytocin has been administered intranasally to investigate its therapeutic potential in schizophrenia and obesity. Although the pathophysiology and mechanisms of oxytocinergic dysfunction in metabolic syndrome and schizophrenia are both complex and it is still too early to draw a conclusion upon, oxytocinergic dysfunction may yield a new mechanistic insight into schizophrenia pathogenesis and treatment.

Effect of Integrated Psychobehavioral Care on Emotional-Behavioral Responses, Cognitive Changes in Outpatients with Schizophrenia Followed Up: Based on a Prospective Randomized Controlled Study

Background

In recent years, influenced by the continuous improvement and development of the medical service model and the increasing demands of modern people for the quality of clinical care, the clinical treatment of schizophrenic groups has also received widespread attention and importance from all sectors of society. Psychobehavioral care is administered to patients during active antipsychotic treatment, which can maximize the patient's cooperation with clinical work and thus play an auxiliary role in treatment.

Aims

To investigate the impact of emotional-behavioral responses, cognitive changes in outpatient follow-up of schizophrenic patients with integrated psychobehavioral care.

Materials and Methods

One hundred cases of schizophrenia patients with outpatient follow-up in our hospital from March 2017 to March 2019 were selected as prospective study subjects and divided into a comparison group and an observation group of 50 cases each according to a random number table. Among them, the comparison group implemented conventional psychobehavioral care, and the observation group implemented integrated psychobehavioral care. The differences in compliance behavior, negative emotions, cognitive behavioral changes, and pain scores before and after care of schizophrenia patients in the outpatient follow-up were compared between the two groups.

Results

After care, the compliance behavior, negative emotions, cognitive behavioral changes, and pain scores of schizophrenia patients in both groups with outpatient follow-up were significantly improved and significantly higher in the observation group than in the comparison group, and statistics showed that this difference was statistically significant (P < 0.05).

Conclusion

Integrated psychobehavioral care combined with conventional psychobehavioral care can effectively enhance the compliance behavior of outpatient follow-up schizophrenia patients, improve the negative emotions and pain of patients, and facilitate the active treatment of patients to improve their prognosis. It has some reference value for outpatient follow-up schizophrenia patient care.