Elevated densities of CD163+ perivascular macrophages have been reported in schizophrenia post-mortem brain tissue, particularly in regions involved in neurodevelopment, dopaminergic signaling, and blood–brain barrier (BBB) regulation. However, the biological significance and developmental lineage of these findings remain unclear. While CD163 is linked to regulatory and scavenging functions, macrophage activation states form a continuum and cannot be inferred from any single marker. This Perspective outlines a structured, testable research framework to determine whether this accumulation reflects altered responsiveness to persistent intracellular, inflammatory, systemic, or treatment-related signals. To test this, we propose sequential methodological aims, including defining CD163+ cell localization and phenotypes in predefined brain regions, and assessing viral and non-viral molecular signals using spatial transcriptomic and cell-specific methods. This framework also involves comparing macrophage activation states across schizophrenia and other psychiatric and non-psychiatric control groups, using single-cell and single-nucleus sequencing. By not presuming a specific infectious aetiology, this approach will provide a general methodology to investigate macrophage-related mechanisms across diverse potential triggers. Within this model, HSV-1 is evaluated strictly as an illustrative proof-of-concept candidate for testing intracellular pathogen responses, rather than an exclusive cause, as epidemiological associations have been inconsistent and localization of viral materials within these cells has not been demonstrated. Similarly, Bacille Calmette–Guérin (BCG)-associated trained immunity is introduced strictly as a preliminary, ex vivo/in vitro approach to probe macrophage reprogramming and plasticity. Ultimately, this framework provides a systematic approach for investigating macrophage-related mechanisms and their potential drivers in schizophrenia without presupposing a specific underlying aetiology.
A novel mutation in SETD1A is associated with early-onset epilepsy—a rare case report
SET Domain Containing 1A (SETD1A) is a histone H3K4 methyltransferase implicated in neurodevelopmental disorders. Pathogenic variants in this gene are associated with schizophrenia, intellectual disability, and epilepsy. Here, whole-exome sequencing and Sanger sequencing were performed on a 4-year-old Chinese girl with early-onset epilepsy and her unaffected parents. A novel de novo heterozygous variant in SETD1A (NM_014712.3: c.1067C > T/p.Ser356Phe) was identified in a patient presenting with focal-to-bilateral tonic–clonic seizures, beginning at 3 months of age. Neuroimaging revealed a normal brain MRI, and comprehensive neuropsychological assessment indicated preserved cognitive function. The variant was absent in 200 local controls and classified as likely pathogenic per ACMG criteria. This study may expand the mutation and phenotypic spectrum of SETD1A-related disorders, establishing the relationship between SETD1A variants and isolated early-onset epilepsy without accompanying severe neurodevelopmental deficits, highlighting the value of genetic testing in infants with unexplained epilepsy.
Association of MAP2 gene polymorphisms and altered expression with schizophrenia risk in a Chinese Han population
BackgroundSchizophrenia (SCZ) is a highly heritable primary psychotic disorder. The microtubule-associated protein 2 (MAP2) gene is essential for dendritic integrity and synaptic plasticity, positioning it as a key candidate for bridging genetic risk and neuropathology. Nevertheless, the role of common genetic variations within MAP2 in SCZ susceptibility remains to be elucidated.MethodsWe conducted a candidate gene association study of MAP2 in a Han Chinese cohort comprising 418 SCZ patients and 418 matched healthy controls. Targeted sequencing was used to genotype single nucleotide polymorphisms (SNPs). MAP2 mRNA levels were quantified by RT-qPCR and correlated with genotypes and clinical symptoms. Bioinformatic tools (such as GTEx, BrainSeq, 3DSNP, HaploReg, RegulomeDB and SNP2TFBS database) were employed for functional annotation of risk loci.ResultsWe identified multiple MAP2 SNPs associated with SCZ risk in a Han Chinese cohort. Specifically, the AA genotype of rs288057 and the GG genotype of rs288087 were significantly associated with increased disease risk (OR = 2.393 and 2.258, respectively). Expression analysis revealed a marked reduction in peripheral MAP2 mRNA levels in patients compared to controls. This downregulation was genotype-dependent: the risk AA at rs288057 and GG at rs288087 were correlated with lower mRNA levels, a finding supported by its significant eQTL effect in the GTEx and BrainSeq database. In silico annotation suggested rs288087 resides within a putative enhancer region, while rs288057 may affect a promoter-proximal regulatory site. Clinically, MAP2 expression showed a significant positive correlation with the severity of negative symptoms (SANS score). Furthermore, ROC analysis indicated that MAP2 expression levels distinguished patients from controls with an AUC of 0.728.ConclusionThis study identifies MAP2 as a schizophrenia risk gene, wherein non-coding variants likely reduce its expression via distinct regulatory mechanisms, linking this downregulation to core negative symptoms. These findings highlight MAP2’s pathophysiological and translational relevance.
Dynamic changes of gut microbiota during progression of three Alzheimer’s disease mice models
IntroductionAlzheimer’s disease (AD) is an age-related and progressive neurodegenerative disorder characterized by cognitive impairment and irreversible neuronal degeneration, affecting approximately 55 million individuals worldwide. Despite extensive research efforts, the underlying pathogenic mechanisms of AD remain incompletely understood, and effective therapeutic strategies for preventing or delaying disease progression are still lacking. Increasing evidence suggests that the microbiota-gut-brain axis plays an important role in neurodegenerative diseases, including AD. However, the dynamic alterations of gut microbiota during AD progression across different transgenic mouse models remain poorly characterized.MethodsIn the present study, we investigated age-dependent changes in gut microbiota composition in three commonly used AD mouse models, including APP/PS1, 3xTg, and 5xFAD mice, using 16S rRNA gene sequencing. Fecal samples were collected longitudinally at 2, 4, 6, and 8 months of age to evaluate microbial diversity, community structure, and differential bacterial taxa during aging and disease progression.ResultsOur results demonstrated distinct and model-dependent alterations in gut microbiota composition across different stages of AD progression. Significant changes in microbial diversity and bacterial community structure were observed among the three AD mouse models and wild-type controls. In particular, dynamic alterations in Verrucomicrobiota, Proteobacteria, and Actinobacteriota were consistently identified during aging in AD mice. In addition, β-diversity, Linear discriminant analysis effect size (LEfSe), and correlation network analyses further revealed differential microbial signatures associated with different AD mouse models and age stages.DiscussionOverall, our findings provide additional evidence that gut microbiota composition undergoes dynamic alterations during aging in multiple AD mouse models and may be associated with AD-related progression. This study may contribute to a better understanding of microbiota-associated changes during AD development and provide a basis for future mechanistic studies targeting the microbiota-gutbrain axis in AD.
Amelioration of tic disorder by Jujuboside A via gut microbiota remodeling and intestinal 5-HT signaling
BackgroundTic disorder (TD) is a common chronic neuropsychiatric condition manifesting during childhood and adolescence. Jujuboside A (JuA) may alleviate TD symptoms; however, the mechanisms underlying its therapeutic effects remain unclear.MethodsWe established a rat model of TD and used histological techniques to evaluate the effects of JuA on pathological changes. We also measured 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels and assessed tryptophan hydroxylase 1 (TPH1) mRNA expression. Finally, we analyzed the gut microbiota composition in fecal samples using 16S rRNA metagenomic sequencing.ResultsJuA administration alleviated pathological changes in rats with TD, increased 5-HT and 5-HIAA levels, and upregulated TPH1 mRNA expression. Compared with no treatment, JuA treatment increased the proportion of Bacteroidia, Muribaculaceae, Bacteroidales, and Bacteroidota, while reducing that of Bacilli, Lactobacillaceae, Lactobacillus, Lactobacillales, and Firmicutes.ConclusionThese findings indicate that JuA mitigates TD progression, potentially by remodeling the gut microbiota and regulating 5-HT levels.
Large-scale meta- and cross-trait analyses uncover shared genetic risk factors for IBS and psychiatric disorders
IntroductionIrritable bowel syndrome (IBS) is a common gut-brain axis disorder characterized by abdominal pain and altered bowel habits, and it shows high comorbidity with psychiatric disorders. However, the shared genetic mechanisms underlying these associations remain incompletely understood.MethodsWe performed a large-scale meta-analysis of IBS in individuals of European ancestry by integrating genome-wide association study (GWAS) summary statistics from the UK Biobank, Bellygenes, and the Million Veteran Program (MVP), thereby increasing statistical power to detect novel IBS loci. We further conducted global genetic correlation analyses with psychiatric traits, followed by multi-trait analysis of GWAS (MTAG) and conditional false discovery rate (condFDR) analyses to identify pleiotropic loci. Transcriptomic, methylomic, and expression quantitative trait locus (eQTL) data were integrated to explore potential regulatory mechanisms.ResultsThe meta-analysis identified up to ten previously unreported IBS loci, several of which were supported by colonic and brain eQTL effects. Global genetic correlation analyses confirmed substantial genetic overlap between IBS and psychiatric traits, particularly major depressive disorder and neuroticism. MTAG and condFDR analyses uncovered more than 100 pleiotropic loci, including signals at SORCS1, SLC35D1, COA1, and TLE1. Integrative analyses of transcriptome- and methylome-wide data highlighted regulatory mechanisms spanning colonic, immune, and neuronal tissues, supporting neuro-immune crosstalk and mitochondrial involvement.DiscussionOur findings provide a comprehensive genetic characterization of IBS, refine its heritable basis, reveal pleiotropic links with psychiatric disorders, and implicate molecular pathways across the gut-brain axis. These results advance mechanistic understanding of IBS and may inform future therapeutic development for IBS and its psychiatric comorbidities.
Phenotype, Genetics, and Interpretation: Further Considerations on Atypical Depression
We read with great interest the recent article by Shin et al. (1). The authors leveraged the substantial Australian Genetics of Depression Study (AGDS) cohort to provide compelling evidence for the clinical and biological validity of the atypical depression subtype. Their integrative analysis of clinical features, polygenic scores (PGSs) for mental, metabolic, and circadian traits, and self-reported treatment outcomes is a significant contribution to the field. The particularly robust finding of an association between a genetic predisposition for eveningness (lower-chronotype PGS) and atypical depression, which persisted after adjustment for body mass index (BMI), is noteworthy and points to a potentially core, BMI-independent pathway.
Comorbidity alters the genetic relationship between anxiety disorders and major depression
The extensive genetic overlap between anxiety disorders (ANX) and major depression (MD) may partly reflect inclusion of comorbid cases in genome-wide association studies (GWAS). We investigated this genetic relationship between ANX and MD with and without mutual comorbidity.
Sex-specific impact of vitamin D and B9 concentrations on neuroticism: a polygenic score-based study
IntroductionNeuroticism is a personality domain with prognostic value for physical and mental health. To properly inform public health policy, it is crucial to uncover the mechanisms underlying high neuroticism. Many internal and external factors that affect brain development and functioning and therefore might contribute to the variability of neuroticism remain understudied. Among them, the impact of vitamin sufficiency is of great interest, as it is a modifiable factor. This study aimed to evaluate the associations of neuroticism with vitamin D (VD) and vitamin B9 (VB9) using polygenic scores (PGS) in a nonclinical cohort.MethodsWe analyzed data from 348 healthy unrelated individuals, including neuroticism scores on the Eysenck Personality Inventory, VD-PGS, VB9-PGS and PGS for neuroticism-related traits.ResultsThe analysis controlling for demographic and genetic confounders revealed a negative association between VB9-PGS and neuroticism scores in women and a positive association between VD-PGS and neuroticism scores in men. The highest values of the VD-PGS were observed in men, who scored high on both neuroticism and extraversion. In men, unlike women, neuroticism scores were not correlated with PGS for neuroticism but were associated with PGS for bipolar disorder type 1 and alcohol use disorders.ConclusionThe results suggest that the effects on neuroticism of genetic propensity for suboptimal vitamin D and B9 concentrations might differ across the two sexes. The findings are consistent with the idea of the importance of vitamin B9 for emotional stability in women and indicate the involvement of genetic factors predisposing to higher vitamin D levels in excitability-related components of neuroticism in men.
Brain Gene Variations Help Explain Neurological and Psychiatric Sex Differences
Thousands of genes are expressed differently in the brains of men and women, researchers have discovered.
The findings could help explain differences in neurodevelopmental, psychiatric, and neurodegenerative disorders between the sexes.
While men are more likely to experience schizophrenia, attention deficit hyperactivity disorder, and Parkinson’s disease, women are more prone to mood disorders and Alzheimer’s disease.
The U.S. study, in Science, is the first systemic single-cell survey of sex differences in gene expression across multiple regions of the human brain.
“Together, these findings provide a comprehensive map of molecular sex differences in the human brain and offer initial insight into their underlying mechanisms and potential functional consequences,” Alex DeCasien, PhD, from the National Institute of Mental Health in Bethesda, Maryland, told Inside Precision Medicine.
DeCasien and co-workers conducted a high-resolution analysis of gene expression in tissue samples from the brains of 15 men and 15 women using single-nucleus RNA sequencing.
They then used data from earlier large neuroimaging studies to select six cortical regions to sample, four of which showed sex-related differences in grey matter volume and two in which no such differences were found.
The team found subtle but widespread differences in gene activity between men and women. Biological sex explained very little of the variance in gene expression across the brain, at less than 1%, but differences were widespread—with more than 3000 genes showing different expression according to sex in at least one cortical region.
The greatest sex-related differences in gene expression were on the sex chromosomes. However, most of the genes showing sex-related variations in expression were autosomal—carried on one of the 22 numbered non-sex chromosomes.
The predominant driver for sex-biased expression of genes on these autosomal chromosomes were sex steroid hormones such as estrogen and testosterone.
Surprisingly, more than half the X chromosome genes in women were expressed in both alleles for at least one cell type. This indicated that many had escaped X chromosome inactivation—a female phenomenon in which one of the two X chromosomes is switched off early in development to stop women producing double the number of X-linked gene products to men.
“That finding has implications for understanding sex-biased disease susceptibility because several genes implicated in neurodevelopmental disorders reside on the X chromosome,” commented Jessica Tollkuhn, PhD, from Cold Spring Harbor Laboratory, and S Marc Breedlove, from Michigan State University, in an accompanying Perspective article.
They noted that autosomal genes showing sex-biased expression were substantially enriched for extracellular matrix components, hormone signaling pathways, and metabolic processes. “Genes with greater expression in women were enriched for mitochondrial and synaptic functions, whereas male-biased genes were associated with metabolic and structural pathways,” the editorialists added.
“By pinpointing these sexually differentiated processes, the data provide a treasure trove for the discovery of biomarkers of and/or therapeutic targets for differential disease risk in men and women.”
DeCasien and team added: “These findings raise the possibility that sex differences in gene expression modulate the magnitude of genetic effects at risk loci, contributing to differences in disease vulnerability and to reduced portability of polygenic risk prediction across sexes.”
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