Molecular Psychiatry

Major depressive disorder (MDD) lacks accessible molecular markers that reflect brain pathology and monitor treatment response. Using the neuron-specific protein SNAP25, we investigated the cargo of neuron-derived extracellular vesicles (NEVs) isolated from plasma in relation to antidepressant treatment and identified miR-151a-5p as a mediator of treatment response, increasing selectively in responders while remaining low in non-responders. Plasma levels mirrored deficits in human post-mortem brain tissue from the ventral anterior cingulate cortex, a cortical area implicated in MDD. In mice, engineered NEVs enriched with miR-151a-5p delivered cargo selectively to neurons, where miR-151a-5p engaged the RNA-induced silencing complex and regulated genes involved in synaptic networks, including RIMS3 and ELAVL3. Moreover, administration of miR-151a-5p-loaded NEVs in a model of depressive-like behavior produced rapid antidepressant-like effects. Together, these findings identify a vesicle-based mechanism linking peripheral biomarkers to central pathophysiology and demonstrate that miR-151a-5p functions both as a predictor and effector of antidepressant response.

Recent large-scale studies have enabled new knowledge about genetic underpinnings of morphological and electrophysiological alterations of the retina. Variation in retinal traits, often of neurodevelopmental origin, have been linked to major psychiatric disorders (MPDs). Here, we investigate the genetic overlap between MPDs and key retinal traits to identify underlying molecular mechanisms. We obtained genome-wide associations studies data for bipolar disorder (BD), major depression (MD), schizophrenia (SCZ), and the retinal traits retinal nerve fibre layer thickness (RNFL), ganglion cell inner plexiform layer thickness (GCIPL), and vertical cup-disc ratio (VCDR). We estimated the number of trait-influencing variants shared between traits with MiXeR and identified shared genetic loci with condFDR. Subsequently, we examined the biological pathways of the genes mapped to shared loci. This revealed that GCIPL shared the most genetic variants with MPDs (~60%), followed by RNFL (~40%), and VCDR (~20%). The genetic variants shared between retinal traits and MPDs showed disorder-specific patterns with more pronounced overlaps of SCZ and BD with RNFL, and MD negatively correlated with GCIPL. Gene-pathway analysis highlighted the importance of GABAergic neurotransmission and a two-stage neurodevelopmental process in SCZ, whereas the role of mitochondria and a weaker developmental component were observed in BD. The results also implicated synaptic functioning and gene-expression processes in MD. Furthermore, polygenic analysis suggested that the genetic architecture of retinal traits can distinguish between MPDs. Our findings indicate shared genetic underpinnings between retinal traits and SCZ, BD, and MD, implicating altered neurodevelopment and neurotransmission underlying the retinal link to major psychiatric disorders.

Major depressive disorder (MDD) has been associated with accelerated structural brain aging, yet whether this reflects a pre-existing neurobiological vulnerability, a dynamic acute state effect, or an accumulating biological residual remains unresolved. Across two longitudinal cohorts (N=3220), including a unique sample of 78 initially healthy individuals who transitioned into their first depressive episode during the study course, we systematically tested all three hypotheses. Patients with diagnosed MDD showed elevated MRI-derived brain age relative to healthy controls (1.4 and 2.5 years across cohorts). For the vulnerability hypothesis, individuals scanned prior to their first episode showed no baseline elevation, despite already demonstrating subclinical elevations in self-reported symptom severity, indicating that advanced brain age does not precede illness onset. For the state hypothesis, we found no acceleration of brain aging following the first depressive episode, and longitudinal brain age trajectories were independent of acute clinical symptom severity. Finally, neither episode duration nor recurrence scaled with brain age. Accelerated brain aging in depression is therefore neither an antecedent vulnerability nor an acute state marker of the first episode, but rather a stable biological feature of a long term illness course.

Psychiatric disorders are complex conditions characterized by substantial overlap in genetic risk and shared biological mechanisms. However, how individual risk genes contribute to shared disease mechanisms and disorder-specific phenotypes remains poorly understood. BRD1 has emerged as a chromatin-associated regulator with transdiagnostic relevance across psychiatric disorders and a central role in gene regulatory networks enriched for psychiatric risk genes. To investigate the biological consequences of reduced BRD1 function in a translationally relevant system, we generated a minipig model harboring a monoallelic deletion in BRD1 and performed longitudinal neuroimaging together with behavioral and multi-omics profiling. BRD1 haploinsufficient minipigs displayed normal growth and exploratory behavior but exhibited subtle age-dependent differences in motivational behavior. Despite the absence of overt developmental abnormalities, longitudinal neuroimaging revealed genotype-associated structural differences primarily involving the cerebral cortex and caudate nucleus, suggestive of altered neurodevelopmental trajectories. Integrated multi-omics analyses revealed striking convergence across transcriptomic and metabolomic datasets, identifying coordinated perturbations of mitochondrial function, redox regulation, and phospholipid metabolism across multiple brain regions. Notably, these molecular alterations were not restricted to the central nervous system, as peripheral multi-omics profiling revealed systemic metabolic alterations, including altered phospholipid composition and glucose metabolism. Together, these findings indicate that BRD1 haploinsufficiency is associated with coordinated neurodevelopmental and metabolic alterations across brain and peripheral tissues. More broadly, this study provides systems-level insight into how a psychiatric risk gene influences interconnected neurodevelopmental and metabolic processes across multiple levels of biological organization and highlights the value of large-animal multi-omics models for translational neuropsychiatric research.

Rare genetic variants associated with psychiatric disorders are thought to have larger individual effect sizes and direct biological roles, offering a unique opportunity for understanding causal relationships between genetic architecture and disease phenotypes. A recent whole-exome sequencing meta-analysis identified an increased burden of ultra-rare protein-truncating variants (PTVs) in AKAP11 in patients with bipolar disorder and schizophrenia. AKAP11 encodes an A-kinase anchoring protein that mediates the association of protein kinase A (PKA) and its substrates. How ultra-rare AKAP11 variants contribute to psychiatric disorder pathogenesis remains unknown. Here, using CRISPR-Cas9 genome editing, we introduced into the mouse Akap11 locus an ultra-rare PTV identified in a human patient with bipolar disorder. This ultra-rare PTV reduced Akap11 mRNA and protein levels without producing stable novel mRNA isoforms, leading to Akap11 haploinsufficiency. Male heterozygous mice exhibited behavioral abnormalities consistent with anxiety- and depression-like phenotypes. Transcriptomic and proteomic profiling of the neocortex revealed molecular changes involving synaptic organization, synaptic signaling, and neurite morphogenesis. Notably, the heterozygous mutant showed selective elevation in type I, but not type II, PKA regulatory subunits, as well as PKA catalytic subunits, in the neocortex. Functionally, these changes were accompanied by reduced phosphorylation of PKA substrates, attenuated stimulus-dependent PKA activity in cortical excitatory neurons, and impaired nascent dendritic development in cortical neurons. Together, our study presents a clinically relevant and genetically precise mouse model that provides mechanistic insight into how ultra-rare PTVs may contribute to psychiatric disorder pathogenesis, and a platform for testing rational therapeutics.

Genetic studies of post-traumatic stress disorder (PTSD) implicate immune regulation, yet linking peripheral immune-related proteins to brain molecular regulation and experimentally tractable targets remains challenging. Cellular and spatial genetic analyses were used to characterize the cellular and spatial genetic context of these traits. We then conducted bidirectional Mendelian randomization (MR) across 30 predefined Ig-like plasma proteins and 16 behavioral and neuropsychiatric traits. The forward MR screen identified four associations meeting the prespecified screening criteria, all of which underwent the same post-screening robustness assessment. CD33-PTSD showed the most consistent support across instrument definitions and applicable robust estimators and was therefore advanced as the prioritized candidate to regional genetic, brain molecular QTL, and functional analyses. Standard CD33 pQTL-PTSD colocalization did not support a simple shared single-variant model, while multi-signal analyses remained scientifically unresolved under the available LD reference. Meanwhile, plasma CD33 pQTL and cortical CD33 eQTL showed strong regional sharing (PP4=0.96468). Regional localization, cross-analysis candidate selection, and functional annotation further suggested a complex regulatory context across the CD33-SIGLEC region. Among 284 compounds with prior CD33 binding evidence that entered structure-assisted screening, 11 were retained as candidates for experimental follow-up. Overall, CD33-PTSD was the prioritized association identified by our screening; subsequent regional genetic, brain molecular QTL, and functional annotation analyses further delineated the complex regulatory context of the CD33- SIGLEC locus, while the CD33-centered structure-assisted exploration yielded 11 compound candidates for subsequent experimental validation.

Background: Major depressive disorder (MDD) is clinically heterogeneous, but relationships among cortical hemodynamic abnormalities, peripheral neuroimmune, metabolic, and oxidative stress (NIMETOX) processes, and clinical phenome features remain unclear. We applied a systems-biology approach integrating functional near-infrared spectroscopy (fNIRS), peripheral NIMETOX biomarkers, and multidimensional clinical phenomes. Methods: Patients with MDD (n = 86) and demographically matched healthy controls (HC, n = 40) underwent 89-channel high-density fNIRS during resting-state and verbal fluency task (VFT) conditions. Temporal hemodynamic variability (Difference) and area under the concentration-time curve (AUC) were derived from oxygenated hemoglobin (HbO), deoxygenated hemoglobin (HbR), and total hemoglobin (HbT) signals. NIMETOX assessments included inflammatory biomarkers, generalized and lipophilic antioxidant defenses, oxidized lipids, lipidomics, and 16S rRNA amplicon sequencing of the stool microbiome. Results: MDD showed reduced VFT Difference and AUC across HbO, HbR, and HbT. Difference reductions were widespread across prefrontal, frontal eye field, language-related, and sensorimotor cortices, whereas AUC abnormalities were more restricted and resting-state alterations were limited. VFT differences significantly differentiated MDD from HC, with further improvement after integrating NIMETOX biomarkers. Lower antioxidants, carnitines/acetylcarnitines, polyunsaturated and even-chain saturated fatty acids, inflammation, indices of gut dysbiosis and leaky gut, and adverse childhood experiences explained substantial variance in HbO, HbR, and HbT Difference. Integrated fNIRS-NIMETOX profiles explained substantial variance in overall illness severity (cross-validated R2= 0.62) and physiosomatic symptoms (cross-validated R2= 0.48). Conclusions: Systems-biology integration identified a multilevel MDD phenotype linking peripheral NIMETOX dysregulation with task-evoked cortical hemodynamic abnormalities and clinical phenome heterogeneity, supporting an interconnected gut-NIMETOX-brain pathophysiology. Key words: major depressive disorder, biomarkers, redox mechanisms, lipophilic antioxidants, oxidized lipids

Schizophrenia, bipolar disorder, and major depression vary in their age of onset, cognitive impacts, degree of impairment, and clinical course. However, since psychosis is a transdiagnostic feature that occurs across all three of these disorders, they can be represented as a spectrum. We leveraged genomic data to explore different functionally distinct components of the psychosis spectrum. We used Genomic Structural Equation Modelling (Genomic SEM) to define four factors indexing specific aspects of psychosis-related symptoms shared across depression, schizophrenia, and bipolar disorder: a general Psychosis factor with low Cognitive functionality (gPsychosisCognition), a specific Psychosis factor independent of cognition (sPsychosis), a specific Affective factor independent of psychosis (sAffective) and a specific Mania factor independent of depression (sMania). We then used Stratified Genomic SEM and transcriptomic analyses to characterize biological functions and temporal trends associated with these factors. sPsychosis, sAffective, and sMania exhibited differential genetic correlations with personality, with sPsychosis and sAffective showing positive correlations with Openness, while Neuroticism showed a strong positive correlation with sAffective and a negative correlation for sMania. GABAergic, cortical, and CA1-CA3 enrichments were significant across the continuum with evidence for factor specific enrichment: dentate gyrus, CA4 and cerebellum were non-significant only for sAffective and oligodendrocytes enriched only in gPsychosisCognition. Transcriptomic analyses revealed different temporal expression trends across factors, identifying a mostly prenatal expression for sMania and sAffective, and more consistent expression across development for sPsychosis. We demonstrated that a clinically informed genomic model can shed light on the functional heterogeneity of psychosis, identify both unique and shared biological components and highlight its partial neurodevelopmental origin.

Psychosis has long been conceptualized as a disorder of disrupted hierarchical integration across distributed brain systems, yet it remains unclear whether alterations in macroscale cortical hierarchy are already present before illness onset and are associated with subsequent transition to psychosis. Using connectome gradient mapping, we characterized baseline cortical hierarchical architecture along the unimodal-to-transmodal axis in 580 participants from the NAPLS-3 cohort, including converters (CHR-C, n = 56), non-converters (CHR-NC, n = 434), and healthy controls (HC, n = 90). Group differences were assessed at regional, network, and global levels. Group comparisons revealed that CHR-C individuals, relative to the other two groups, exhibited bidirectional alterations selectively along the sensorimotor-to-association gradient, with reduced values in the visual network alongside elevated values in the default mode network, indicating greater separation between sensory and transmodal systems along the gradient. At the global level, CHR-C showed increased explained variance, range, and variation of this gradient, collectively indicating hierarchical expansion. Notably, greater explained variance of this gradient was associated with a shorter time to conversion to psychosis, while increased gradient range and variation were associated with higher positive symptom severity across CHR individuals. These findings indicate that expansion of the sensorimotor-to-association connectome hierarchy is already present before psychosis onset in individuals who subsequently convert to psychosis. This altered hierarchical organization may reflect greater decoupling between sensory and transmodal systems and may characterize neurobiological changes associated with progression from a clinical high-risk state to psychotic illness.

Dysregulated dopamine signaling is implicated in schizophrenia and mood disorders, yet how disease-associated genes alter dopamine dynamics during behavior remains poorly understood. ATP2A2 encodes sarco/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2), a regulator of intracellular Ca2+ homeostasis, and has been associated with psychiatric vulnerability. Brain-specific Atp2a2 heterozygous conditional knockout (het-cKO) mice exhibit behavioral abnormalities and elevated extracellular dopamine in the nucleus accumbens (NAc) with microdialysis, but it lacks the temporal resolution to resolve rapid, context-dependent dopamine dynamics. Here, we used dual-site fiber photometry with the genetically encoded dopamine sensor dLight1.2 to monitor dopamine signals simultaneously in the NAc and tail of the striatum (TS) during classical reward conditioning. Control and het-cKO mice acquired task-related licking comparably. Nevertheless, het-cKO mice showed enhanced NAc reward-evoked dopamine responses in the pooled analysis, with indications of more frequent and longer-lasting spontaneous transients. Responses to unexpected reward omission were larger in het-cKO mice in both regions during the early phase, but they were not detected after further training. Notably, late-phase suppression of reward-predictive NAc dopamine responses by a preceding aversive outcome persisted in het-cKO mice, although evidence for genotype dependence was inconclusive. Regional dopamine transporter (DAT) protein expression showed no clear genotype differences. These findings identify context-dependent alterations in dopamine signaling across multiple temporal scales and striatal regions in brain-specific Atp2a2 haploinsufficiency, highlighting intracellular Ca2+ regulation and dopamine release as priorities for direct investigation. These results may help clarify the biological links between ATP2A2 haploinsufficiency and neuropsychiatric dysfunction.

Maternal depression and psychosocial adversity during pregnancy are associated with altered offspring neurodevelopment, yet the molecular processes linking maternal state to the developing fetus remain incompletely understood. The placenta is positioned to sense and respond to maternal physiological signals, but how placental molecular responses relate to those in the developing brain is unclear. Here, we used a mouse model of prolonged social isolation initiated before conception and maintained throughout pregnancy to investigate inflammatory and transcriptional alterations across matched placenta and fetal-brain samples at gestational day 18. Maternal social isolation altered cytokine profiles in both tissues and induced extensive transcriptional changes in the placenta, with a more restricted response in the fetal brain. Functional analyses identified alterations in placental immune, metabolic and transport-related programmes and fetal-brain immune, neuronal and proliferative processes. Although sex-stratified analyses revealed different transcriptional profiles in male and female tissues, formal maternal housing x fetal-sex interaction testing did not identify significant gene-level interaction effects. Cross-tissue co-expression analysis initially identified extensive covariation between social-isolation-responsive placental and fetal-brain modules; however, most associations were attenuated after accounting for their shared relationship with maternal housing. An exposure-independent network analysis nevertheless identified an inverse pregnancy-level association between a placental module enriched for immune and interferon-related signalling and a fetal-brain module enriched for cell-cycle and proliferative processes. Together, these findings show that prolonged maternal social adversity is associated with coordinated but tissue-distinct molecular alterations across the placenta-fetal brain axis and demonstrate the importance of distinguishing parallel responses to a common maternal environment from direct cross-tissue molecular coupling.

Abstract Human induced pluripotent stem cells (hiPSCs) provide a translational platform to interrogate the impact of genetic risk factors for various disorders on human biology. It has been a common practice to engineer premature stop codons to model predicted loss-of-function mutations using isogenic hiPSCs, yet effects of mutation position for the same gene and genetic background have been rarely tested systematically and at multiple levels for comparison to those of patient-specific mutations. Ultra-rare, heterozygous, and predicted loss-of-function mutations in the SETD1A gene, which encodes a H3K4 methyltransferase, are highly penetrant genetic risk factors for schizophrenia. Here, we generated a large panel of isogenic heterozygous SETD1A mutant hiPSC lines, including premature stop-codon mutations in one early exon and one late exon in five genetic backgrounds and two patient-specific mutations, to gain insight into molecular, cellular, and functional changes in a disease-relevant and highly pure population of human hippocampal dentate granule cell-like neurons. Our multi-level analyses showed that different SETD1A mutations lead to divergent molecular and cellular phenotypes related to synapses, but convergent neuronal network deficits, while the genetic background influences gene expression with no substantial effects at cellular and network levels. Mechanistic analysis confirmed the early exon patient mutation as loss-of-function, but revealed that the predicted loss-of-function patient mutation in the late exon is likely gain-of-function. Consequently, while all mutations decreased global H3K4me3 levels, deficits were only partially rescued by inhibiting H3K4 demethylase LSD1 for early exon mutations, but not for late exon mutations. Together, these results suggest that highly penetrant mutations can lead to similar cellular and functional phenotypes across different genetic backgrounds, whereas different premature stop-codon mutations could have contrasting impacts due to distinct mechanisms. Our findings have practical implications for applying genome-editing in hiPSCs to model disorders, highlight the value of modeling patient-specific mutations and testing multiple mutations, and suggest the need for tailored mutation-dependent therapeutic strategies.

Background: Major depressive disorder (MDD) is associated with brain dysfunction and age-related diseases. Epigenetic clocks based on DNA methylation patterns estimate biological aging and aim to predict morbidity and mortality. Although MDD has been linked to epigenetic age acceleration (EAA) cross-sectionally, it is unknown whether EAA is associated with MDD after trauma. Methods: We included 706 participants (66% non-white, 64% female) from the multi-ancestry AURORA study, enrolled at emergency departments (ED) within 72 hours after trauma, from whom three age-adjusted epigenetic clocks were measured at enrollment: PhenoAge, GrimAge, and DunedinPACE. Functional MRI and assessment for probable MDD were conducted two weeks and six months later, respectively. Logistic and linear regression models tested the association of EAA with MDD and functional neuroimaging endpoints. Results: A total of 660 participants had available assessments of probable MDD six months after trauma, and from those 160 screened positively (24.2%) after trauma. EAA calculated by GrimAge (OR = 1.44, 95% CI = 1.12 - 1.85, p-adj= 0.012) and DunedinPACE (OR = 1.46, 95% CI = 1.15 - 1.85, p-adj = 0.005), but not PhenoAge (p-adj= 0.239), was significantly associated with MDD 6-months after trauma. Associations remained significant after adjusting for additional confounders, including prior trauma and disability (p= 0.008 for GrimAge, p= 0.010 for DunedinPACE). Subgroup analysis based on a median age split revealed these effects were only observed in participants 35 years of age or older. DunedinPACE was significantly associated with altered connectivity of fourteen brain network pairs after FDR correction (n = 217). Conclusions: EAA is associated with a higher risk of MDD after trauma and with concomitant brain connectivity changes. Calculation of GrimAge and DunedinPACE at the time of ED presentation may help recognize patients at risk for MDD, potentially improving personalized care after trauma.

Suicidal behavior results from complex behavioral and biological changes. Previous cross-sectional studies indicate that proinflammatory immunobiological factors are often increased in close temporal proximity to a suicide attempt. Suicidal individuals may also exhibit a biological trait vulnerability to stress and inflammation, due to persistent epigenetic modifications. We enrolled 130 individuals with major depressive disorder (MDD), 83 with suicidal behavior at intake, and followed them for 12 months with up to eight clinical assessments. Quantification of plasma inflammatory markers and metabolites was performed by high-sensitivity electrochemiluminescence and Ultra High-Performance-Liquid-Mass Spectrometry (UPLC-MS), respectively. Epigenetic changes were identified using Illumina EPIC arrays. We identified 15 genes with altered DNA-methylation associated with suicidal behavior and attempts at baseline. Childhood trauma predicted lifetime suicide attempts and was associated with altered methylation of seven genes. Increased neutrophils and lower plasma serotonin at baseline predicted future suicide attempts over the following year (neutrophil estimate = 0.42, P = 0.016; serotonin OR = 0.58, 95% CI: 0.39-1.13). Utilizing biomarkers from baseline and epigenetic data from the genes with highest predictive values (STBD1 ,PRDM8, and TRIM15), we achieved an area under the curve (AUC) of 0.84 for suicide attempts over the year. Suicidal behavior in MDD was associated with specific epigenetic signatures. Several of the identified genes, such as MAD1L1, have been implicated in psychiatric disease, suicidal behavior and the immune response. These findings support the usefulness of epigenetic and immunometabolic blood markers for identifying suicidal individuals in clinical settings, potentially enhancing preventative efforts.

Major depressive disorder (MDD) is strongly associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, systemic inflammation, and gut microbiota dysbiosis. Although selective serotonin reuptake inhibitors such as escitalopram are standard treatments, their efficacy is often constrained by partial response and gastrointestinal adverse effects. In this 12-week, randomized, double-blind, placebo-controlled trial, we evaluated the clinical efficacy and microecological mechanisms of adjunctive Lactiplantibacillus plantarum PS128 (PS128; 6*1010CFU/day) in MDD patients on stable escitalopram therapy. Adjunctive PS128 significantly enhanced clinical response compared to placebo, yielding substantial reductions in HAMD-17 and MADRS, alongside a higher remission rate. 16S rRNA sequencing and PICRUSt2 profiling revealed that PS128 enriched key short-chain fatty acid producers (Faecalibacterium, Coprococcus), counteracting the Klebsiella expansion seen in placebo. Functionally, PS128 up-regulated neuroprotective cofactor, B vitamins, biosynthesis and down-regulated the neurotoxic kynurenine pathway. Network analysis demonstrated that PS128 maintained a resilient, integrated microbial co-occurrence topology, whereas the placebo network showed structural segregation. This stabilized ecosystem attenuated peripheral inflammatory signaling and normalized salivary cortisol levels. Overall, adjunctive PS128 augments escitalopram efficacy by enhancing gut network stability, supporting cellular energetics, and modulating neuroendocrine activity, offering a promising multimodal strategy for MDD.

Background: Bipolar disorder (BIP) and obsessive-compulsive disorder (OCD) frequently co-occur and show evidence of genetic overlap, yet the specific pleiotropic loci and their functional mechanisms remain unclear. Methods: We conducted large-scale genetic analyses using GWAS summary statistics for BIP and OCD, excluding 23andMe data. We applied conjunctional FDR analysis to identify pleiotropic variants jointly associated with BIP and OCD, followed by integrative annotation through transcriptomic (eQTL, sQTL), epigenomic (mQTL, haQTL), and proteomic (pQTL, histone PTM) data. SMR analysis was used to prioritize putative regulatory effects, while AlphaGenome predictions and targeted histone proteomics were employed to evaluate allele-specific chromatin changes. Results: We observed a significant genetic correlation (rg = 0.38, P = 3.8 x 10-29) and extensive polygenic overlap between BIP and OCD. Bidirectional MR supported causal effects in both directions, with stronger evidence for BIP influencing OCD risk. ConjFDR analysis revealed 2,143 pleiotropic SNPs jointly associated with BIP and OCD, with convergent signals at the ITIH3/ITIH4 locus. Summary-data-based Mendelian randomization (SMR) and colocalization with multi-omic QTLs (eQTL, pQTL, mQTL, and haQTL) further prioritized the ITIH3/4 locus, where multiple SNPs (e.g., rs3774364) colocalized with H3K27ac histone acetylation QTLs in the prefrontal cortex (PP_H4 > 0.5). Integrated PBMC RNA-seq and complementary histone mass spectrometry linked immune--ECM transcriptional activity to exploratory global histone acetylation changes in BIP and OCS-BIP, with suggestive alterations in H3K27ac-containing peptides. Conclusions: Our multi-omic analysis highlights ITIH3/ITIH4 as a prioritized pleiotropic locus for BIP and OCD. Epigenetic regulation, particularly through histone acetylation, may underlie shared susceptibility and offers a novel mechanistic link between these psychiatric disorders.

Background: Schizophrenia is characterized by widespread structural and functional brain abnormalities, yet it remains unclear whether these alterations converge across imaging modalities and whether such convergence is associated with underlying cellular distribution and evolution of the human cortex. Methods: We performed coordinate-based meta-analyses of seven whole-brain neuroimaging modalities, including cortical thickness, gyrification, voxel-based morphometry, amplitude of low-frequency fluctuations, regional homogeneity, regional cerebral blood flow (all based on magnetic resonance imaging), and glucose metabolism based on [18F]-Fluorodeoxyglucose positron emission tomography. The analyses included 200 studies (209 datasets) comprising 11,794 patients with schizophrenia and 10,342 healthy controls. After single-modality meta-analyses using seed-based d-mapping, the meta-analytic result maps were integrated using orthonormal projective non-negative matrix factorization. Finally, the resulting component maps were related to maps of cortical cell type-specific gene expression and human-specific cortical evolution. Results: Multimodal integration identified a robust convergence pattern centered in bilateral insular, mediofrontal, and lateral sensorimotor cortices, with the strongest contributions from regional homogeneity, cerebral blood flow, and amplitude of low-frequency fluctuations. The convergence pattern showed significant spatial correspondence with cortical gene expression profiles of astrocytes, microglia, and oligodendrocyte progenitor cells. In contrast, we found no evidence for a preferential localization to regions of human-specific cortical expansion or connectivity. Conclusions: Structural and functional brain abnormalities in schizophrenia converge on an insular-mediofrontal-sensorimotor pattern that aligns with glial gene expression profiles. These results support glia-related regional vulnerability as an organizing principle of multimodal brain abnormalities in schizophrenia.

Adolescent depression is a major neuropsychiatric disorder induced by early life stress; the underlying cellular mechanisms instigating pathological circuit malformation remain unclear, and, consequently, effective therapeutic strategy is limited. Here, we analysed the contribution of astrocytes to early life stress-induced adolescent depression using a mouse model of parental separation. We identified a previously unrecognised regional specialisation of lateral habenula (LHb) astrocytes, characterised by compact cellular domains, abundant leaflets, and enhanced Cx43 gap junctional coupling. Parental separation selectively reduced astrocytic Cx43 expression and gap junctional communication in the LHb, which was accompanied by profound astrocytic atrophy and loss of leaflets. Single-cell sequencing further revealed that parental separation induces a broad reorganisation of LHb astrocyte transcriptional states, including metabolic, stress-response, and inflammatory programs; moreover, it specifically reduces astrocyte-neuron communication. Consistent with this, we found that structural remodelling of LHb astrocytes affected tripartite synapse geometry, resulting in impaired excitatory and inhibitory synaptic transmission, and neuronal Ca2+ hyperexcitability, all ultimately associated with depressive-like behaviours. Selective knockdown of astrocytic Cx43 in the LHb recapitulated these pathological changes and translated into depressive-like behaviours. Mechanistically, we found that impaired Cx43 gap junctional communication is associated with excessive astrocytic Ca2+ dynamics, resulting in Rac1-GTPase activation and decreased p-Ezrin levels. In vivo inhibition of LHb astrocytic Ca2+ signalling rescued astrocytic atrophy and depressive-like behaviours following parental separation. Together, our findings establish a Cx43-Ca2+-Rac1-p-Ezrin pathway that links gap junction malfunction to structural remodelling of astrocytes and disruption of neuron-astrocyte interactions in the developing LHb. Our study reveals astrocytic Ca2+ dysregulation as an active downstream effector of Cx43 dysfunction and identifies a regionally specialised astrocytic mechanism through which early-life stress disrupts synaptic transmission and neuronal function during adolescence, providing a potential cellular target for intervention in adolescent depression.

Schizophrenia (SZ) is a severe psychiatric disorder characterized by psychosis, cognitive deficits, and disrupted social functioning. Mitochondria are essential for neuronal function, synaptic plasticity, and behavior, all impaired in SZ. A major driver of mitochondrial dysfunction in SZ is Complex I, particularly its NDUFV2 core subunit, whose alterations occur post-transcriptionally. We previously showed that the NDUFV2 pseudogene (NDUFV2P1; PG) is upregulated in brain and peripheral cells of SZ patients and inversely correlates with NDUFV2 expression and mitochondrial respiration in Epstein-Barr-virus-transformed lymphocyte cells lines (LCLs). In-silico analyses excluded small RNA interference with NDUFV2, implicating PG as an interfering factor. To study PG effects on NDUFV2 expression, mitochondrial function, and neuronal activity, we modulated PG abundance in LCLs. PG overexpression in healthy-derived LCLs impaired mitochondrial function, altering {Delta}{psi}m, mitochondrial network dynamics, and oxygen consumption, while PG downregulation in SZ-derived LCLs restored these parameters to normal levels. In rat cortical neurons, PG overexpression induced comparable mitochondrial disruptions alongside impaired synapse formation and reduced spontaneous neuronal firing. This study provides evidence for a mechanistic pathway through which PG interferes with NDUFV2, leading to SZ-related mitochondrial and neuronal deficits, and suggests therapeutic potential for PG downregulation in diseases with bioenergetic impairments such as SZ.

Metabotropic glutamate receptors (mGluRs) regulate glutamatergic transmission and have been implicated in diverse neuropsychiatric disorders, but human postmortem evidence remains fragmented. We aimed to map these findings across diagnoses, receptor subtypes, brain regions, and measurement modalities. Following PRISMA guidelines, we systematically searched MEDLINE, EMBASE, and Web of Science from inception to August 8, 2026, for studies assessing GRM transcripts, as well as mGluR protein abundance, localization, assembly, or receptor binding in human postmortem brain tissue. Of 532 records identified, 57 reports met eligibility criteria. Findings were synthesized narratively because of substantial heterogeneity in diagnoses, brain regions, receptor subtypes, and assays. Postmortem evidence was concentrated on mGluR5, mGluR2/3, and mGluR1, and on the prefrontal cortex, anterior cingulate cortex, and hippocampus. mGluR-related alterations were reported across disorders, including schizophrenia, major depressive disorder, Alzheimer disease, autism spectrum disorder, and alcohol use disorder. Although most analyses yielded null findings, the direction and magnitude of mGluR alterations varied across brain regions, receptor subtypes, and molecular endpoints. This inconsistency may partly reflect the distinct biological levels captured by transcript abundance, total protein, receptor assembly, localization, and ligand binding, together with regional, cell-type, disease-stage, and clinical heterogeneity. The available evidence therefore suggests context-dependent alterations in mGluR biology but not a uniform or disorder-specific molecular signature. Integration of postmortem findings with other approaches, including in vivo imaging, may clarify their biological and clinical significance.