Search Results (495)

In postmortem Alzheimer’s disease (AD) brains, Porphyromonas gingivalis (Pg), a major periodontal pathogen, and Candida albicans, one of the most common fungal pathogens, have been detected. Although it is important to better understand the effects of their co-infection in the brain for elucidating the pathogenesis of AD, little is known about the neuropathological significance of such co-infection. In the present study, we aimed to elucidate the effects of co-exposure to virulence factors derived from Pg and C. albicans on microglial inflammatory responses. We demonstrated, for the first time, that both candidalysin dissolved in dimethyl sulfoxide (CLd) and water (CLw) significantly suppressed Pg lipopolysaccharide (LPS)-induced interleukin-1β (IL-1β) production by 35–60% and nuclear factor-κB (NF-κB) activation by 20–40%. It should be noted that contaminating Pg outer membrane lipoproteins in Pg LPS were mainly responsible for IL-1β production. To examine the possible hydrophobic interactions between lipoproteins contaminating the Pg LPS preparation and CL, we used 8-anilino-1-naphthalenesulfonic acid sodium salt (ANS-Na), which can be excited to emit fluorescence by binding of hydrophobic molecules. The mean fluorescence intensity of ANS-Na was significantly reduced by approximately 26% following co-treatment with CLw and Pg LPS compared with CLw alone. Furthermore, we generated a mutant form of CL with reduced hydrophobicity (GRAVY index: 1.106 vs. 0.874) while preserving its predicted structural properties. This mutant CLd no longer inhibited Pg LPS-induced IL-1β production. Taken together, these findings indicate that hydrophobic interactions between lipoproteins contaminating the Pg LPS preparation and CL mediate the inhibitory effect of CL on Pg LPS-induced inflammatory responses. The present findings suggest that interactions between polymicrobial virulence factors in the brain may modulate microglia-mediated inflammatory responses during AD progression. Full article

Major depressive disorder (MDD) has been linked to oxidative stress, mitochondrial dysfunction, and impaired neuronal plasticity, but the reproducibility of related transcriptomic alterations across postmortem brain cohorts remains uncertain. We performed a targeted cross-platform analysis of a prespecified 14-gene panel spanning antioxidant defense, mitochondrial-redox regulation, cellular stress responses, neurotrophic signaling, synaptic plasticity, and polyamine metabolism across seven postmortem dorsolateral prefrontal cortex cohorts comprising 146 MDD cases and 179 controls. Primary support required Fisher-combined evidence, Benjamini–Hochberg correction across the panel, and concordant MDD-minus-control direction across all available cohorts. NPTX2, EGR1, VGF, BDNF, and SAT1 met these criteria, with lower expression in MDD. The same five-gene pattern was supported by weighted signed Stouffer analysis, one-stage generalized least-squares models, random-effects meta-analysis, and 200,000 disease-label permutations; none produced at least five genes meeting the complete primary-support criterion (empirical p = 5.0 × 10⁻⁶). The most robust cross-cohort finding was a convergent lower-expression pattern across genes supporting redox-linked stress adaptation, polyamine homeostasis, neurotrophic signaling, activity-dependent transcription, and synaptic plasticity. This pattern suggests impaired molecular capacity for neuronal stress resilience and adaptive plasticity in MDD. Full article

Neurodegenerative diseases represent a major and growing global health burden. Although these disorders are often clinically defined by symptoms and affected brain regions, many are mechanistically linked to abnormal protein accumulation, misfolding, impaired proteostasis, RNA dysregulation, mitochondrial dysfunction, and neuroinflammation. In this Perspective article, I discuss major neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, multiple system atrophy, amyotrophic lateral sclerosis, frontotemporal dementia, Huntington’s disease, prion diseases, spinocerebellar ataxias, and spinal muscular atrophy, through the lens of disease-associated proteins and experimental modeling. I argue that a protein-centered framework provides a useful approach for understanding disease mechanisms and selecting transgenic mouse models, while recognizing that aging, cellular context, neuroinflammation, mitochondrial dysfunction, vascular dysfunction, and other disease modifiers also shape neurodegeneration. Transgenic and genetically engineered mouse models have been essential for dissecting the pathogenic roles of amyloid-β, tau, α-synuclein, TDP-43, SOD1, FUS, C9ORF72-associated dipeptide repeat proteins, mutant huntingtin, prion protein, ataxins, and SMN deficiency. However, these models have important limitations, including artificial overexpression, familial mutation bias, species differences, and incomplete representation of aging-related sporadic diseases. Rather than seeking a single “best” model, a more productive strategy is to adopt model portfolios tailored to specific biological questions and to integrate mouse studies with human cellular models, postmortem tissue, omics approaches, and biomarker-based validation. Such an approach may improve mechanistic insight, strengthen translational relevance, and enhance the predictive value of preclinical neurodegenerative disease research. Full article

A previous study identified [¹¹C]M503-1619 as a lead compound for positron emission tomography (PET) radiotracer development. The goal of the current study was to conduct a structure–activity relationship (SAR) study on M503-1619 to improve its in vitro binding affinity for alpha synuclein (aSyn), as well as to identify potential radiotracers that could be labeled with fluorine-18. The results of the SAR study identified strict SARs regarding the introduction of a fluorine into the N-aryl piperazine and benzamide moieties. The most promising compound was the corresponding 2-fluoroethyl analog of M503-1619. This compound was radiolabeled with fluorine-18, followed by in vivo PET imaging studies on non-human primate and in vitro autoradiography study. In vitro autoradiography studies in human postmortem brain sections demonstrated that ¹⁸F-labeled radiotracer has higher binding to synucleinopathies versus control brain tissues. This radiotracer displays the high initial brain uptake and rapid washout that is needed for a PET radiotracer for imaging a protein such as aSyn that has a low target density in the brain. However, the formation of brain penetrant radiolabeled metabolites prevented further evaluation of this compound. Insights from this SAR study are guiding the development of novel aSyn radioligands that avoid formation of the undesirable radiolabeled metabolite. Full article

The neuronal ceroid lipofuscinoses are the most common group of human paediatric genetic neurodegenerative disorders and have also been reported in multiple animal species. This study explores sheep with the CLN6 disease subtype, which occurs in humans either as a late-infantile or as an adult-onset disease. This study characterised morphometric changes that occur in the brains of 15-month-old Merino sheep with CLN6 disease compared to healthy, adult Merino control brains using ultra-high field magnetic resonance imaging (MRI). The formalin-fixed brains of seven affected and three wild-type control sheep were scanned in a 9.4 T Bruker MRI scanner with a T1-weighted gradient echo. Bioimaging technology ‘Amira-Avizo’ was used to segment each region of interest to create a 3D reconstruction of each ovine brain. Volumetric and statistical analysis of each region of interest found that the thalamus, corpus callosum, occipital cortex, hippocampal region and striatum of affected sheep all experienced a significant loss of volume; 80%, 77%, 73%, 50%, 46% respectively, compared to the control brains. The left side of the affected brain showed a significant reduction of 44%, while the volume of the lateral ventricle non-significantly increased by 43%. However, the cerebellum and arbour vitae of affected sheep lost 15% and 8% of their volume, respectively, which was not significant. These findings are overall consistent with previous gross pathology, histopathology and traditional in vivo MRI findings of ovine CLN6 disease models, but suggest that postmortem ultra-high field MRI of formalin-fixed brains can be a complementary approach to in vivo studies. Volumetric analysis of affected brain regions, including the corpus callosum, thalamus, occipital cortex, striatum, and hippocampal region, can provide valuable biomarkers for assessing the effectiveness of therapeutic interventions in NCL. Full article

α-Synuclein (α-Syn) is a key presynaptic protein, primarily known for its role in the pathogenesis of Parkinson’s disease (PD) and other synucleinopathies, including dementia with Lewy bodies (DLB). Although much of the research has focused on the nigrostriatal dopamine (DA) pathway, there is growing recognition that the accumulation of misfolded α-Syn in the prefrontal cortex (PFC) is a critical driver of non-motor symptoms and cognitive deficits in PD and DLB. This review examines the dual role of α-Syn in the PFC circuitry, initially exploring its regulation of synaptic vesicle (SV) dynamics and recycling to maintain stable neurotransmission. We highlight its contribution to the modulation of glutamatergic (Glu) and GABAergic (γ-aminobutyric acid, GABA) synapses, which ensures the functional excitatory/inhibitory (E/I) balance of prefrontal circuits. Conversely, in PD and DLB, the transition of functional α-Syn monomers to pathological oligomers triggers a cascade of synaptic failures. We analyze how α-Syn aggregation causes pathology in dendritic spines, leads to a progressive reduction in the density of synaptic markers, and impairs cortical plasticity. Synthesizing evidence from neuroimaging studies, post-mortem human cortical samples, and animal models, this review emphasizes the PFC as a vulnerable brain region where α-Syn-mediated synaptic dysfunction translates into cognitive and emotional deficits. Deciphering these early synaptic alterations is essential for developing neuroprotective strategies that preserve cortical function in PD and DLB. Full article

Mitochondrial dysfunction has been increasingly implicated in the pathobiology of neurodevelopmental conditions, particularly autism and attention-deficit/hyperactivity disorder (ADHD). Because the developing brain is critically dependent on sustained ATP production, impairments in oxidative phosphorylation, mitochondrial dynamics, and redox balance may disrupt neuronal maturation, synaptic development, and neural circuit refinement during sensitive developmental periods. This review examines evidence from postmortem neurochemistry, genomics, magnetic resonance spectroscopy, and biomarker research to characterize mitochondrial impairment across autism and ADHD. Studies in autism report an elevated burden of heteroplasmic mitochondrial DNA (mtDNA) variants, along with alterations in mtDNA copy number, respiratory chain capacity, fission–fusion dynamics, and antioxidant defenses. Postmortem data demonstrate reduced activity of electron transport chain Complexes I, III, and V in the frontal cortex, temporal lobe, and cerebellum. These bioenergetic abnormalities are accompanied by elevated oxidative stress markers alongside mitochondria-mediated immune activation. In vivo neuroimaging corroborates these findings through elevated cerebral lactate and reduced phosphocreatine-to-ATP ratios. Evidence in ADHD is limited, but similarly implicates mitochondrial dysfunction, consistent with the frequent co-occurrence of these conditions and their partially shared architecture. The available literature supports mitochondrial dysfunction as a transdiagnostic biological feature of neurodevelopmental conditions, with relevance to mechanistic biomarker identification and targeted therapeutic development. Full article

Gene expression analyses of postmortem brains have identified hundreds of dysregulated genes in schizophrenia (SCZ) and bipolar disorder (BD). Lactate accumulation and reduced brain pH are also consistently reported in these disorders. As increased TGFB expression has been implicated in major psychiatric diseases and lactic acid induces TGFB2 upregulation in metabolic diseases, we hypothesized that lactate-induced brain acidosis may drive widespread gene dysregulation through TGFB2 activation. In our previous microarray studies, increased TGFB2 expression was observed in postmortem brains of SCZ and BD patients, while pathway analyses suggested a key role for TGFB2 in the dysregulation of other genes, particularly astrocytic genes. TGFB2 itself also exhibited promoter DNA hypomethylation in postmortem brains of these patients. Here, while brain pH was lower in SCZ and BD patients, we investigated the effects of pH alteration on the expression and promoter DNA methylation of TGFB2 and TGFB2-correlated genes in iPSC-derived neurons, astrocytes, and brain organoids (brainoids). Cultures were treated with lactic acid, HCl, bicarbonate, or NaOH to alter culture medium pH by ±0.4 units, and gene expression and promoter DNA methylation were evaluated by qPCR analyses. In our reanalysis of postmortem brain microarray data, nearly 80% of dysregulated genes, together with TGFB2, exhibited inverse correlations with brain pH. Lactic acid treatment induced increased expression and promoter DNA hypomethylation of TGFB2 and several correlated genes in astrocytes and brainoids, whereas bicarbonate and NaOH treatments showed opposite effects. These findings suggest that lactate-mediated brain acidosis may contribute to TGFB2 upregulation and widespread gene dysregulation implicated in SCZ and BD pathogenesis. Therapeutic interventions targeting lactic acid accumulation or TGFB2 hyperexpression may mitigate disease-associated brain gene dysregulation. Full article

The diversity and abundance of the brain virome is an active field of investigation. However, how the brain virome relates to the presence of viruses outside of the nervous system remains unclear. The rationale for this study is that analyses across multiple biologically linked compartments within the same individuals provide an important opportunity to evaluate virome discordance and viral burden. To characterize viral prevalence and burden across anatomical compartments, we applied the targeted viral enrichment method ViroFind to matched postmortem brain (n = 66), cerebrospinal fluid (CSF; n = 24), and peripheral samples (spleen, peripheral blood mononuclear cells, and lymph nodes; n = 66) from individuals with and without human immunodeficiency virus (HIV) infection and substance use disorder (SUD) in the National NeuroAIDS Tissue Consortium. We detected nucleic acids from 27 viruses representing 12 taxa. Several viruses, including adenovirus, torque teno virus, Epstein–Barr virus, human herpesvirus 6 and 7, cytomegalovirus, parvovirus, and JC polyomavirus, showed significant inter-compartment differences in prevalence or burden. CSF exhibited lower overall viral diversity than brain or peripheral samples, whereas peripheral samples showed the highest viral burden. CNS viral detection was more likely when the same virus was also detected in the periphery. We also detected HBV and HCV in CNS samples despite them not being classically regarded as neurotropic. Broader virome profiling showed greater peripheral viral burden and diversity in HIV-positive than HIV-negative individuals, whereas SUD was not associated with overall viral burden differences. These findings highlight important cross-compartment differences in viral detection, including occurrence of occult HBV infection within the CNS, and support the value of CNS–periphery comparisons in virome studies. These findings can contribute to improved diagnosis and management of viral infections. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder traditionally defined by dopaminergic neuronal loss and Lewy body pathology; however, increasing evidence indicates that metabolic dysfunction contributes to both motor and non-motor manifestations of disease. While metabolomics studies in PD have largely focused on peripheral biofluids or subcortical brain regions, metabolic remodeling within cortical regions critical for cognition remains poorly characterized. Here, we applied LC-MS/MS-based untargeted metabolomics to post-mortem frontal cortex tissue from PD and neurologically normal control donors, with statistical models adjusted for age, sex, and post-mortem interval. A total of 893 metabolites were quantified, of which 234 exhibited significant differential abundance following false discovery rate correction. Pathway enrichment and network-based integration revealed coordinated metabolic remodeling characterized by predicted inhibition of β-alanine metabolism and pantothenate-dependent coenzyme A biosynthesis alongside activation of amino acid, vitamin B-dependent, cofactor-related, redox-associated, oxidative stress, and inflammatory pathways. Recurrent alterations in pantothenic acid, β-alanine-related intermediates, arginine- and histidine-derived metabolites, lumichrome, and vitamin B₆-associated species may reflect cortical metabolic perturbations associated with mitochondrial bioenergetic vulnerability and oxidative stress. Together, these findings indicate selective metabolic vulnerability in the PD frontal cortex rather than diffuse metabolic collapse. Full article

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by amyloid-β (Aβ) and the accumulation of tau in the brain, which triggers robust innate immune responses. Growing evidence indicates that neuroinflammation contributes to AD progression by overactivating microglia through the release of cytokines and chemokines. In general, chemokines can disrupt neuronal communication and promote blood–brain barrier permeability. Peripheral immune cells are mobilized into the brain by a gradient of chemokines. These processes link peripheral immune responses with substantial T-cell infiltration into the CNS parenchyma, leptomeninges and cerebrospinal fluid of both AD mice and AD patients. This finding underscores the relevance of the adaptive immune system, particularly T and B cells, in AD neuropathology. T-cell infiltration into the brain can influence amyloid clearance through chemokine signalling. However, chemokines play a critical role in AD by either promoting or suppressing disease progression. The infiltration of peripheral T and B cells into the brain parenchyma can exacerbate neuronal loss, yet it may also exert neuroprotective effects. Despite the presence of CD4⁺ and CD8⁺ T cells in postmortem brains of AD patients, debate continues about their role in AD brains, in terms of whether they are protective or detrimental. Understanding the complex role of chemokines in controlling innate and adaptive immune responses by modulating neuron–glia interactions (involving astrocytes and microglia) may provide novel therapeutic approaches for AD. Targeting chemokine signalling or treating with drugs that can prevent the recruitment of immune cells may be promising strategies for treating AD neuropathology. Therapies that prevent the overactivation of T cells in the brain could lead to protective strategies against AD. In fact, regulatory T cells (Tregs) could delay the onset of cognitive symptoms, because they suppress inflammation and slow the accumulation of Aβ plaques and p-Tau in the brain. Complementary strategies, such as photobiomodulation, nanoparticle, and T-cell-based approaches, could mitigate AD progression in patients. Full article

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by complex interactions among genetic, environmental, and biological factors. Increasing evidence suggests that immune system processes intersect with neurodevelopment in ways that may influence brain maturation, synaptic organization, and large-scale network function. However, existing literature is often fragmented across molecular, cellular, and systems levels, limiting the development of a coherent interpretive framework. In this review, we propose a developmental neuroimmune cascade model of ASD, in which early-life immune perturbations, arising from prenatal or perinatal factors, may interact with genetic susceptibility to influence cytokine signaling, microglial function, blood-brain barrier dynamics, and gut-immune communication. These processes may, in turn, affect synaptic pruning, excitatory-inhibitory balance, and the maturation of neural circuits, contributing to alterations in large-scale brain networks implicated in sensory processing, interoception, and social cognition. We synthesize evidence from observational human studies, postmortem analyses, and experimental animal models to examine how immune-related mechanisms may contribute to neurodevelopmental trajectories associated with ASD, while explicitly distinguishing associative findings from mechanistic inference. Particular attention is given to the role of distributed network vulnerability, including, but not limited to, insula-centered systems that integrate internal bodily states with affective and cognitive processing. Finally, we consider implications for biomarker development and stratified intervention approaches, emphasizing the importance of developmental timing, biological heterogeneity, and cautious interpretation of translational potential. Rather than positioning immune dysfunction as a singular cause of ASD, this model conceptualizes neuroimmune processes as modulators of developmental trajectories, offering a structured basis for future research linking immune signaling to circuit-level and behavioral outcomes. Full article

The intracellular accumulation of amyloid beta 42 (iAβ42) has been proposed as an early pathological indicator of familial Alzheimer’s disease (FAD). DJ-1 is a multifunctional protein sensitive to oxidative stress (OS) that has been associated with neurodegeneration; however, its role in iAβ42 pathology is unclear. In this study, we examined whether oxidized (sulfonic) DJ-1 (Cys¹⁰⁶-SO₃H) drives iAβ42 accumulation using postmortem brain samples and in vitro 3D iPSC-derived cerebral organoids (COs) or 2D induced pluripotent stem cells (iPSC)-derived ChLNs (cholinergic-like neurons) models from a PSEN1 E280A patient and a healthy volunteer (as a control sample). Post-mortem analyses of the temporal and frontal cortices and hippocampus from FAD PSEN1 E280A patients revealed strong intracellular co-localization of sulfonic DJ-1 and iAβ42, which was absent in control samples. To validate these findings, we generated COs from an iPSC PSEN1 E280A FAD patient and a healthy donor. In these organoids, we observed the co-localization of oxidized DJ-1 and Aβ42 in the absence of extracellular fibrils or plaques, as confirmed by BTA-1 staining. To further support these observations, 2D iPSC PSEN1 E280A-derived ChLNs cultures showed that intracellular Aβ42 accumulates progressively in direct correlation with increasing DJ-1 oxidation, as demonstrated by immunofluorescence microscopy and Western blotting analysis. These results indicate that DJ-1 oxidation accompanies the earliest intracellular stages of Aβ42 pathology. Furthermore, complementary in silico molecular docking analysis revealed a higher affinity between Aβ42 and oxidized sulfonic DJ-1 (DJ-1 Cys¹⁰⁶-SO₃H) compared to sulfenic (DJ-1 Cys¹⁰⁶-SOH) or sulfinic acid (DJ-1 Cys¹⁰⁶-SO₂H) forms. Likewise, ELISA tests and seeding assays confirmed that oxidized DJ-1 binds to and decelerates Aβ42 aggregation kinetics. Together, our results identify DJ-1 oxidation as a critical molecular event in the accumulation of iAβ42 in FAD. These findings suggest that oxidized DJ-1 represents not only a potential early biomarker of intracellular pathology but also a pharmacological target. Preventing the oxidation of DJ-1 or its pathological aggregation could provide new biomarkers and therapeutic strategies for reducing the intracellular accumulation of Aβ42 and neurodegeneration in FAD. Full article

Severe mental disorders, including schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder (MDD), are leading causes of global disability, yet current treatments remain largely symptomatic and fail to alter disease trajectories. Converging evidence from genetics, longitudinal studies, and systems neuroscience supports a dimensional and transdiagnostic architecture of psychopathology, involving shared polygenic risk and overlapping neurodevelopmental and circuit-level alterations. Traditional approaches—such as post-mortem brain analysis, neuroimaging, and animal models—have delineated core molecular perturbations (e.g., dopaminergic, glutamatergic, and GABAergic dysfunction), as well as informed translational frameworks for mechanistic investigation, but remain constrained by restricted access to dynamic processes and incomplete recapitulation of human-specific biology. The advent of human-derived cellular models, particularly human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs), has partially addressed these limitations, enabling the study of patient-specific neurodevelopment and synaptic function in vitro. Within this evolving landscape, the olfactory neuroepithelium (ONE) has emerged as an accessible source of neural progenitors, obtainable through minimally invasive procedures, providing a window into living human neurobiology. ONE-derived cells retain donor-specific genetic and epigenetic signatures while recapitulating disease-relevant phenotypes across major psychiatric disorders, including altered neurodevelopmental dynamics, synaptic gene expression, and inflammatory profiles. Here, we present a narrative review of the principal cellular and tissue models used in biological psychiatry, examining their respective strengths, limitations, and translational relevance across experimental contexts. By situating these approaches within a unified framework, we aim to clarify their complementarity, identify current gaps, and outline future directions, highlighting the emerging potential of ONE-based models to bridge genetic risk, cellular dysfunction, and clinical phenotype, thereby advancing precision psychiatry. Full article

The aim of this study was to determine whether exposure to low doses of zearalenone (ZEN) over a period of six weeks affects the values of the carry-over factor (COF) of ZEN in the roof of the third cerebral ventricle (RTCV) and in selected skeletal muscles (longissimus and quadriceps) in prepubertal gilts. The study was conducted on 60 clinically healthy prepubertal gilts with an initial body weight (BW) of 14.5 ± 2 kg. Gilts were randomly assigned to a control group (group C; n = 15) and three experimental groups (ZEN5, ZEN10, and ZEN15; n = 15 each). Groups ZEN5, ZEN10, and ZEN15 were administered ZEN per os at doses of 5 µg/kg BW, 10 µg/kg BW, and 15 µg/kg BW, respectively. Group C animals were orally administered a placebo. Tissue samples (brain and skeletal muscles) were collected post-mortem for toxicological analyses on exposure days 7 (D1), 21 (D2), and 42 (D3). The concentrations of ZEN and its metabolites, α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), were determined in the collected samples. All examined tissues contained the parent compound, but ZEN metabolites were not detected in any of the samples. The absence of ZEN metabolites may have resulted from a physiological deficit of estradiol (E₂) and, consequently, testosterone (T) and progesterone (P₄) in prepubertal gilts. Low-dose ZEN mycotoxicosis led to a persistent presence of ZEN in the RTCV (COF from 1 × 10⁻⁶ on D1 to 7 × 10⁻⁷ on D3) and somewhat lower ZEN levels in skeletal muscles (COF from 8 × 10⁻⁶ on D1 to 6 × 10⁻⁷ on D3). The presence of ZEN in the RTCV confirms that it crosses the blood–brain barrier and may therefore participate in the hormonal homeostasis of the brain. Full article