Search Results (509)

Background/Objectives: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by interconnected pathological processes including mitochondrial dysfunction, oxidative stress, impaired autophagic processes, neuroinflammation, neuronal degeneration, and progressive functional decline. Natural health products (NHPs), coenzyme-Q10 (CoQ10) and Ashwagandha (Withania somnifera) (ASH), have been previously reported to possess antioxidant, anti-inflammatory, mitochondrial-supportive, neuroprotective, and neurotrophic properties. This work investigates the neuroprotective effects of a bioavailability-enhanced formulation, Ubisol-Q10 (UQ), and ethanolic ASH extract, combined as a “Tonic,” across multiple domains of AD pathology. Methods: The effects of long-term administration were evaluated in male and female 5XFAD mice from 2.5 to 11 months of age. Longitudinal magnetic resonance imaging assessed hippocampal and white matter volumes, a frailty index assessed physiological resilience, Novel Object and Novel Location Recognition testing assessed spatial and non-spatial memory, while post-mortem Nissl, Golgi–Cox, and immunofluorescence evaluated cellular density, dendritic morphology, amyloid pathology, neuroinflammation, autophagy-associated signaling, and astrocytic activity. Results: Across these measures, Tonic treatment preserved brain volumes, reduced amyloid pathology and inflammation, and modulated autophagy-associated pathways. Treatment also preserved dendritic architecture, frailty progression, and novelty-recognition behavior. Females demonstrated particularly pronounced preservation of white matter structure and increased dendritic density, whereas males showed strong modulation of inflammatory and autophagy-associated markers. Astrocytic immunoreactivity also demonstrated sex- and region-specific patterns, suggesting that glial responses may contribute differently to structural preservation in males and females. Conclusions: Together, these findings support that UQ + ASH may provide diverse protection against AD neurodegeneration. The observed sex-specific responses emphasize the importance of incorporating sex into preclinical evaluation of novel interventions for neurodegenerative diseases. Full article

Sheep-associated malignant catarrhal fever (SA-MCF) is a frequently fatal, pantropic, lymphoproliferative disease caused by ovine gammaherpesvirus 2 (OvGHV2), with sheep serving as the asymptomatic reservoir host. Although the Rusa deer (Cervus timorensis) are known to be highly susceptible to OvGHV2 in other regions, cases have not been documented in this species from Brazil. This report describes the spontaneous occurrence of OvGHV2 infection in a captive Rusa deer from Southern Brazil and discusses possible impacts on wildlife. Three deer from the same property died suddenly without prior clinical signs. These animals had no known contact with sheep or goats, but were maintained in an epidemiological niche where OvGHV2 was detected in subclinically infected free-ranging wild boars (FRWBs) and cattle. One of these was submitted for routine post-mortem evaluations. Gross lesions included ulcerative and erosive lesions of the alimentary tract, pulmonary edema, and marked meningeal congestion. Histopathology revealed erosive and ulcerative esophagitis, abomasitis, omasitis, and rumenitis, with nonsuppurative meningoencephalitis, and vasculitis in several organs, consistent with SA-MCF. Molecular testing of brain tissue detected OvGHV2 DNA by qPCR. Furthermore, PCR assays amplified the partial fragments of the OvGHV2 tegument protein (ORF75) and the glycoprotein (gB) genes. Other neurological pathogens of ruminants including BoAHV5, BVDV, Listeria monocytogenes, Histophilus somni, and rabies virus were not detected. Additionally, phylogenetic analyses, based on ORF75 and gB genes, revealed that the nucleotide sequences derived from this study clustered with and had elevated sequence homology with the OvGHV2 reference strains and other strains derived from ruminants maintained in different geographical locations. The absence of contact with sheep, combined with prior evidence of subclinical OvGHV2 infection in FRWBs and cattle within the same epidemiological niche, suggests the involvement of alternative wildlife reservoirs or bridge hosts in viral transmission. Additionally, these results expand the host range of OvGHV2 in Brazil, highlight the vulnerability of exotic cervids to SA-MCF, and underscore the need for integrated wildlife–livestock surveillance strategies in regions where multiple susceptible species coexist. Full article

Brain aging is characterized by heterogeneous microglial states and altered mitochondrial, metabolic, and lysosomal homeostasis. Mitophagy is central to mitochondrial quality control, but its contribution to age-associated microglial dysfunction remains incompletely understood. This review examines how microglial mitophagy interacts with mitochondrial and lysosomal quality control, immunometabolic adaptation, and inflammatory signaling during brain aging, while distinguishing direct microglial evidence from findings derived from other experimental systems. Aging remodels microglial mitochondrial, metabolic, and lysosomal functions in a state- and context-dependent manner, including reactive, disease-associated, lipid-associated, and senescence-like states. Mitophagy may preserve mitochondrial quality control by limiting the accumulation of damaged mitochondria and associated oxidative and danger signals. However, static mitophagy-associated markers do not establish completed mitophagic flux, which requires mitochondrial delivery to lysosomes and subsequent degradation within them. Human postmortem studies reveal age- and disease-associated alterations in mitochondrial quality control and mitophagy-related pathways, but direct measurements of mitophagic flux in defined human microglial populations remain limited. Age-related changes in lysosomal capacity, acidification, metabolic stress, mitochondrial dynamics, and coordination between mitochondrial clearance and biogenesis may collectively influence microglial resilience. Whether phagocytic and mitophagic cargo directly compete for lysosomal capacity remains unproven. We therefore propose a Microglial Mitophagy Threshold Model as a conceptual, testable framework in which mitochondrial damage, mitophagic clearance, lysosomal capacity, mitochondrial renewal, and microglial state collectively determine mitochondrial homeostasis or persistent inflammatory dysfunction. Microglial mitophagy should be viewed as part of an interconnected mitochondrial–lysosomal quality control network. Direct assessment of mitophagic flux alongside microglial state, mitochondrial dynamics and function, bioenergetics, and lysosomal capacity will be essential to validate this framework. Full article

Digital histology of human postmortem brain tissue is fundamental to understanding neurodegeneration, yet resolving the spatial organisation of neuroinflammatory markers remains challenging because manual scoring and scalar summaries capture only part of the image information. We present a dual-tiered computational framework combining stochastic spatial point-process analysis with explainable deep learning. Using high-resolution spinning-disk confocal immunofluorescence images from a human Parkinson’s disease cohort (Braak Stage 3/4), we analysed spatial associations between IBA1-positive microglia and phosphorylated alpha-synuclein (pSyn) aggregates across the nigrostriatal pathway. Second-order spatial point-process statistics did not detect robust group differences in microglial spatial clustering, while a voxel-level Overlap Index showed a nominal elevation of microglial–pSyn co-occupancy in the substantia nigra that did not survive multiple-testing correction ($d=0.74$, nominal $p=0.045$, BH-adjusted $p=0.550$; diagnosis-by-region interaction $p=0.464$). To test whether pixel-level image information provided donor-level discrimination, we trained 2.5D multi-slice ResNet-18 models under repeated donor-contained cross-validation across all five outer folds, with predictions aggregated to the donor level. In the substantia nigra, the pSyn-only model provided the most consistent discrimination (mean AUROC $0.694\pm 0.062$ across seeds; seed-averaged donor out-of-fold AUROC $0.669$, 95% CI $0.405$–$0.901$), whereas adding IBA1 did not yield measurable incremental discrimination ($\Delta$AUROC $-0.074$, 95% CI $-0.248$ to $0.083$; $p=0.395$). Putamen performance was near chance and unstable across seeds. Cohort-level quantitative attribution analysis indicated that relevance maps were associated with structures present in the input images, but no disease-specific attribution differences survived multiple-testing correction. The framework provides a donor-aware protocol for comparing interpretable spatial summaries, imaging modalities, and held-out explanations; external validation in larger cohorts is required before generalisation. Full article

Psychosis involves striatal circuit dysfunction, but the regional molecular and cellular changes remain unclear. We re-analyzed 215 postmortem RNA-seq samples (72 donors: 36 controls, 28 schizophrenia, 8 bipolar disorder with psychosis) from the nucleus accumbens, caudate and putamen, asking whether diagnosis-associated transcriptional changes are region-specific and whether they reflect cellular composition or cell-intrinsic state. Region-specific limma-voom models identified 0, 141 and 2152 schizophrenia-associated genes (FDR < 0.10) in the nucleus accumbens, caudate and putamen; the small bipolar-psychosis group yielded one gene, with limited power to detect additional associations. Correlation-aware camera tests supported immune–inflammatory Hallmark programs in the caudate and putamen, whereas nucleus accumbens signals were not robust to sequencing-run adjustment. Leukocyte-reference deconvolution was uninformative for brain parenchyma. Across four deconvolution estimators and two single-nucleus references, including an independent eight-donor striatal reference, putamen samples from donors with schizophrenia showed a consistently lower oligodendrocyte-lineage reference weight, whereas attribution to oligodendrocyte precursor cells specifically was method-dependent. Exploratory directional signatures (dopamine–adenosine, glutamate–calcium, Activin–SMAD, APP processing) remained supported in the caudate and putamen after direction-selection permutation conditional on fixed gene membership and were driven mainly by schizophrenia. The results characterize a dorsal–striatal, schizophrenia-associated transcriptional and oligodendroglial signal and provide prioritized hypotheses for independent validation. Full article

Background/Objectives: Sporadic cerebral amyloid angiopathy (CAA) occurs due to a failure of clearance of amyloid-beta (Aβ) along the walls of capillaries and arteries. Soluble Aβ is eliminated from the brain along the basement membranes of capillaries and arteries as Intramural Periarterial Drainage (IPAD). The motive force for IPAD is provided by the spontaneous contractions of vascular smooth muscle cells, as vasomotion. Cerebrovascular smooth muscle cells receive adrenergic and cholinergic innervation from the Locus Coeruleus and the Nucleus Basalis of Meynert, which are compromised very early in Alzheimer’s disease (AD). Here, we tested the hypothesis that adrenergic and cholinergic receptors are histologically preserved in parenchymal and leptomeningeal blood vessels with CAA. Methods: Using immunohistochemistry, we examined the cerebrovascular distribution of muscarinic (M1, M2), nicotinic (α 7 nicotinic acetylcholine receptor), and adrenergic (α1b/2b) receptors in post-mortem brain tissue. We compared receptor distribution across CAA and non-CAA patients, as well as young and old patients without CAA. Results: We found significant differences in the receptor immunoreactivity of α7 nicotinic acetylcholine receptors, as well as α1b and α2b adrenergic receptors. However, there were no differences in the receptor immunoreactivity of M1 or M2 muscarinic receptors between patient groups. Conclusions: As IPAD depends on the functionality of the vascular smooth muscle cells to maintain the integrity of IPAD with aging, based on these histological findings, future therapeutic interventions could focus on agonists of α7 nicotinic acetylcholine and α1b/2b adrenergic receptors. Full article

Frontotemporal lobar degeneration (FTD) and Alzheimer’s disease (AD) are proteinopathies characterized by the abnormal accumulation and aggregation of specific proteins like Aβ-42 deposits, p-tau accumulation, and abnormal cytosolic aggregation of TAR DNA-binding protein 43 (TDP-43) in FTD patients. Recently, the identification of neuroinflammatory mediators as predictors of cognitive decline has gained attention. We have compared several plasma biomarkers of cognitive impairment between AD and FTD patients using Enzyme-Linked Immunosorbent Assay (ELISA) (pg/mL), including CX3CR1 and soluble fractalkine (sFK, also termed CX3CL1), TDP-43, neurofilament light chain M (NfL M), p-tau217, and GFAP (glial fibrillary acidic protein). Chemokines are HIV-1 co-receptors that facilitate the spread of HIV-1 infection and induce apoptosis in the brain. Whilst these chemokines promote neuronal survival and regulate neuron-glia interactions, they also contribute to neurodegeneration. Fractalkine, also known as CX3CL1, is a delta chemokine that binds to its CX3CR1 chemokine receptor. As a membrane isoform, fractalkine can be released in a soluble form by damaged neurons under either inflammatory and/or excitotoxic conditions; since neuroinflammation contributes to neurodegeneration and dementia, we compared these CX3CR1/sFK delta chemokine levels in seropositive patients (with suppressed viral loads) and without neurodegeneration to age-matched controls. This was done in order to study whether inflammation could upregulate these chemokines in the absence of cognitive impairment. To our knowledge, this is the first study showing that increased plasma levels of CX3CR1 and soluble fractalkine could be associated with FTD pathology as compared to control subjects (without neurodegeneration). However, peripheral NfL M, GFAP, and p-tau217 levels did not differ between AD and FTD patients. Post-mortem analysis of human FTD brains revealed anatomical changes, including hippocampal involution and tau deposits. Given that soluble fractalkine can contribute to cognitive impairment while also exerting protective effects against brain insults, we did an additional (independent experiment) in cortical neurons in vitro under LPS-induced neurotoxicity. We confirmed that adding recombinant fractalkine for 24 h prevented lipopolysaccharide (LPS)-induced apoptosis in cortical neurons at 7 days in vitro (DIV); moreover, twenty-four hours after LPS treatment, sFK prevented neuronal apoptosis by decreasing caspase-3 activity and exerted neuroprotective effects against inflammation. Our findings suggest that fractalkine mitigates LPS-induced neuronal injury by limiting apoptosis and inflammatory responses. Furthermore, our findings suggest for the first time that elevated circulating sFK levels may indirectly be associated with FTD pathology as compared to healthy controls. However, sFK could also reflect compensatory protective responses to neuronal injury. Full article

Viral infections have been associated with multiple sclerosis (MS), Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), but the associations may reflect different relationships to the disease process. This review evaluates evidence for viral involvement in disease initiation, modification of established disease, impaired viral control secondary to disease or treatment, and incidental detection. The strongest temporal evidence concerns Epstein–Barr virus (EBV) and MS. Prospective data place EBV seroconversion before clinical onset and the first observed increase in serum neurofilament light chain, while mechanistic studies link EBV infection, B-cell biology, and CNS-directed immunity. However, evidence that ongoing EBV activity modifies established MS remains limited. In AD, experimental studies support interactions between herpesviruses and AD-associated proteins, while the reduced incidence of all-cause dementia after herpes zoster vaccination suggests that viral or immunological pathways may be modifiable, without establishing that a specific herpesvirus initiates AD. Viral associations in PD rely mainly on epidemiological, experimental, and postmortem findings. Human pegivirus detection in a subset of PD brains remains a candidate association requiring independent confirmation and evidence of biological activity. Evidence in ALS is similarly limited. Enterovirus detection has been inconsistent, and altered human endogenous retrovirus K (HERV-K) expression in postmortem tissue does not establish an acquired viral infection. Stronger inference across these diseases will require longitudinal studies relating viral activity and antiviral immunity to subsequent disease-related changes, together with intervention studies that document the intended effect on the implicated viral process and separately assess subsequent disease risk or progression. Full article

Background/Objectives: Sleep and circadian disturbances are common in neurodevelopmental conditions, yet the developmental cortical programs linking clock-related transcriptional regulators to disease vulnerability remain unclear. Methods: Here, we integrated human developmental brain transcriptomes, weighted gene co-expression network analysis (WGCNA), human and mouse cortical single-cell atlases, prenatal immune activation transcriptomes, and ASD postmortem brain datasets to characterize the developmental architecture of BrainSpan-derived cortical programs and examine their behavior in perturbational and disease contexts. Results: In the BrainSpan frontal cortex, canonical clock-related genes followed structured but heterogeneous developmental trajectories rather than behaving as a coordinated oscillator-like unit. WGCNA identified a postnatal-rising BrainSpan-derived primary developmental module that was strongly associated with developmental age and enriched for synaptic signaling, neurotransmitter transport, ion transport, membrane excitability, cellular respiration, metabolic regulation, and proteostatic processes. Network analysis placed multiple canonical clock-related and clock-regulatory genes, including NPAS2, BHLHE40, BHLHE41, PER family members, RORA, NR1D1/2, and CLOCK, within a broader neuronal and homeostatic co-expression architecture, although their module-membership strengths varied substantially. Projection onto a human cortical developmental single-cell atlas revealed a non-uniform distribution of the corrected BrainSpan-derived developmental signature, with relatively higher scores in excitatory and inhibitory neuronal populations and lower scores in neuroblast and radial glial populations. A mouse cortical developmental single-cell atlas provided a comparative view of the stage- and cell-type-dependent expression of clock-related genes and the transferred developmental signature during corticogenesis. In a Poly(I:C)-based maternal immune activation dataset, litter-aware reanalysis identified stage-resolved genome-wide transcriptional responses following E12.5 exposure. However, neither the aggregate core clock-gene expression score nor the independently transferred BrainSpan-derived developmental signature showed a significant overall treatment effect or collection-stage-by-treatment interaction, indicating that this bulk dataset provides a perturbational context rather than evidence for selective disruption of the developmental program. An exploratory region-stratified analysis of GSE28521 yielded near-null effects for the BrainSpan-derived developmental signature, with confidence intervals crossing zero across all examined regions. These ASD postmortem findings were therefore treated as a boundary assessment rather than evidence of ASD-specific convergence. Conclusions: Collectively, these findings position clock-related genes as components of a developmentally regulated cortical maturation program enriched for neuronal signaling, synaptic maturation, metabolic regulation, and stress-response processes. Full article

Ovine coenurosis, caused by the larval stage of Taenia multiceps (Coenurus cerebralis), is a parasitic disease that affects the central nervous system of livestock. While diagnosis traditionally relies on clinical signs, imaging, and postmortem examination, electroencephalography (EEG) remains underutilized despite its potential to detect brain abnormalities. This case report describes EEG and quantitative EEG (qEEG) findings in a 2-year-old sheep presenting with clinical signs suggestive of a chronic focal encephalopathy (ataxia, head tilt and circling) associated with lethargy and progressive weight loss. Computed tomography (CT) confirmed a single, discretely bilobate intra-axial cystic lesion within the left cerebral hemisphere, with a severe mass effect, marked deformation and displacement of the ventricular system, compression of the thalamic structures, and contralateral deviation of the median line. A solitary parasitic cyst with no lesion in the right hemisphere was subsequently confirmed at necropsy and on histopathology. Under ketamine–diazepam sedation, both EEG recordings showed a continuous, delta-dominant background consistent with the anesthetic protocol. Epoch-wise asymmetry indices with bootstrap confidence intervals distinguished an unstable component (which reversed in hemispheric sign between recordings) from a reproducible one confined to the occipital derivations, where the asymmetry lay over the right hemisphere in both recordings in every band except delta. This reproducible preponderance was contralateral to the cyst, over a hemisphere in which no structural lesion was demonstrable either on imaging or at necropsy, and absolute powers indicated that it arose principally from attenuation of the signal recorded over the diseased hemisphere. These findings provide the first electrophysiological characterization of ovine coenurosis and show that in the presence of a severe mass effect, the side of the surface qEEG abnormality may not indicate the side of the lesion (an electrophysiological false localizing sign described in human patients but not previously in a ruminant). EEG therefore reflects the functional brain disturbance caused by Coenurus cerebralis but should be regarded as a complement to, rather than a substitute for, cross-sectional imaging in neurolocalization. Full article

Selective symmetrical encephalomalacia (SSE) is a rare neurological disorder characterized by bilateral and symmetrical areas of malacia within specific regions of the central nervous system and has been reported in humans and several animal species. This report describes a case of SSE in a six-month-old Maine Coon crossbred kitten from Italy that presented with central vestibular dysfunction, rapidly progressive neurological deterioration, proprioceptive deficits, respiratory impairment, seizures, and abnormal vocalization. Clinical evaluation, hematological and biochemical analyses, and ancillary diagnostic testing were performed to investigate the underlying cause and evaluate differential diagnoses. Despite supportive care, the animal died naturally a few days after the onset of clinical signs. A complete postmortem examination, including histopathological evaluation of the central nervous system, was subsequently performed. Neuropathological analysis revealed multifocal, bilateral, and symmetrical malacic and spongiform lesions affecting multiple brain regions, compatible with an SSE pattern. Comparison with previously reported cases in humans and dogs showed marked similarities in lesion distribution and morphology. This case expands the limited knowledge of SSE-like neuropathological lesions in cats and highlights the value of neuropathological examination in the diagnosis of rare neurological disorders presenting with rapidly progressive clinical signs. Full article

Hypoxia-inducible factors (HIF-1α, HIF-2α, HIF-3α) regulate cellular adaptation to oxygen deprivation, but their region-specific roles in Alzheimer’s disease (AD) and AD with cerebral amyloid angiopathy (CAA) remain unclear. Using post-mortem human brain tissue from aging, AD, and AD + CAA groups, we measured all three HIF isoforms in hippocampal subfields (CA1, CA2, CA4, dentate gyrus) and anterior cingulate cortex (ACC) layers 3 and 5. In the AD hippocampus, two distinct patterns emerged: ischemia-resistant regions (CA4, DG) maintained HIF-2α and showed relative resilience, whereas vulnerable regions (CA1, CA2) exhibited HIF-1α upregulation, HIF-3α loss, and HIF-2α dysregulation. The ACC contrasts sharply with the hippocampus by preserving coordinated HIF-1α/HIF-3α regulation during aging and AD, with layer-specific divergence (exhaustion in layer 3 vs. resilience in layer 5) emerging only upon addition of CAA. Notably, HIF-2α in ACC neurons remains stably elevated across all conditions. Taken together, our results highlight HIF-2α as a potential contributor to regional vulnerability and raise the possibility that maintaining HIF-2α levels, in addition to or instead of modulating HIF-1α, could be worthy of further investigation in the context of AD and related vascular changes. Full article

Background: Global cerebral ischemia initiates a cascade of pathophysiological changes that progressively impair subsequent perfusion of brain tissue. Some authors have proposed that adequate cerebral perfusion becomes impossible after approximately 10–30 min of global ischemia. However, the extant evidence base for this threshold and its variations across studies has not yet been systematically examined. Objective: To synthesize the literature on post-ischemic cerebral perfusion success as a function of ischemia duration. Methods: We searched PubMed (11 February 2026) for studies of global cerebral ischemia in animal or human models that reported quantitative or categorical measures of perfusion quality. Eligible studies included those assessing perfusion via restoration of blood flow, via external perfusion of non-blood solutions, and/or via tracer injection following reperfusion. Studies of focal ischemia were excluded. Data extracted included species, ischemia duration, temperature during ischemia, ischemia model, perfusate type, and perfusion quality assessment method. The perfusion quality outcome was operationalized as either the average percentage of brain tissue perfused or the percentage of brains in a group that was adequately perfused. Study quality was assessed using a custom domain-specific checklist. Results: We included 60 studies with 192 study arms reporting on the perfusion of the brains of rabbits, rats, pigs, dogs, cats, and humans. Studies differed in the model of ischemia, the perfusate, the perfusion parameters, the quality assessment methods, and other factors. Longer ischemia was associated with lower perfusion quality, but substantial heterogeneity across studies prevented identification of a consistent sharp temporal threshold. Some studies found that at least partial perfusion was possible after longer periods. Within-study dose–response curves were more consistent than the pooled cross-study pattern. Conclusions: How long the brain remains perfusable after circulatory arrest has not yet been definitively established. On average, perfusion quality clearly declines rapidly as the duration of global cerebral ischemia increases. However, some studies, often using interventions such as hypothermia or vasopressors, have reported at least partial perfusion of the brain even after 30 or 60 min of ischemia. Moreover, at least partial perfusion has been reported in human brain banking studies after postmortem intervals of several hours or days in some donors. Limitations of this review include substantial heterogeneity in study methods and outcome measures, which precluded formal meta-analysis. Future research may benefit from more thorough and precise measures of perfusion quality. Full article

Background: Elevated plasma homocysteine (HCY) is a risk factor for Alzheimer’s disease (AD), but its relationship with structural brain changes across the AD continuum remains unclear. The choroid plexus (CP) regulates cerebrospinal fluid homeostasis and may interface with peripheral metabolic signals. Whether HCY relates to CP structural alterations and disease progression remains unknown. Methods: We analyzed 819 Alzheimer’s Disease Neuroimaging Initiative (ADNI) participants (229 cognitively normal (CN), 397 with mild cognitive impairment (MCI), and 193 with AD dementia). Multinomial logistic regression assessed associations between HCY and diagnosis under stepwise covariate adjustment. Phenotype-wide structural magnetic resonance imaging (MRI) mapping identified HCY-associated signals. Cox models evaluated associations of CP volume (CPV) with CN-to-MCI and MCI-to-AD dementia conversion and whether CPV added prognostic discrimination beyond baseline disease-severity markers. Independent human CP single-nucleus and spatial transcriptomic datasets were reanalyzed to characterize epithelial expression states and their spatial organization in a hypothesis-generating analysis. Results: Higher HCY was associated with MCI and AD dementia; however, the AD association attenuated after adjustment for renal function, vitamin B12, and medications, whereas the MCI association remained stable. CPV was among the HCY-associated MRI signals that persisted after progressive covariate adjustment. Right and bilateral CPV showed model-dependent associations with MCI-to-AD dementia conversion. In the disease-severity sensitivity analysis, larger right and bilateral CPV remained associated with a higher risk of progression from MCI to AD dementia. Single-nucleus analysis identified two CP epithelial states with relatively high expression of one-carbon metabolism-related genes, termed one-carbon metabolism-enriched epithelial state A (OCM-Epi-A) and state B (OCM-Epi-B). Donor-level pseudobulk analysis did not identify pathway enrichment after false discovery rate correction, whereas OCM-Epi-A–like spots were located near endothelial spots more often than expected by chance in three of the four spatial samples. Conclusions: Circulating HCY was associated with larger CPV, and larger CPV showed model-dependent associations with MCI-to-AD dementia progression. Independent transcriptomic reanalysis identified one-carbon metabolism-enriched epithelial states and their spatial organization in postmortem CP tissue, providing hypothesis-generating tissue-level context for the ADNI associations. Full article

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