Biology subjects

Wyss-Coray, T.

Publications and source records attributed to Wyss-Coray, T..

At least 19 recordsLinked to original sources

bioRxiv2026

An atlas of the aging glycoproteome reveals how glycosylation modulates autoantibody binding in the brain

N-glycosylation generates substantial molecular diversity, yet how glycan composition varies throughout aging remains poorly understood. We mapped the N-glycoproteome of brain, liver, spleen, kidney, and plasma across nine ages spanning the mouse lifespan, identifying 80,618 unique N-glycopeptides at 9,211 glycosites on 4,391 glycoproteins, together with matched proteomic trajectories (glycoproteinatlas.org). Organ identity was the dominant determinant of glycan composition, but numerous glycosites nevertheless underwent remodeling with age. The brain showed a prominent age-associated increase in short paucimannose glycans, driven in part by the age-associated increase in the glycan-processing enzyme HEXB. In white matter, a hotspot for this change, aging increased the paucimannosylation of Myelin oligodendrocyte glycoprotein (MOG), a major target of central nervous system autoimmunity. We identified MOG-reactive autoantibodies in aged individuals and patients with MOG antibody-associated disease (MOGAD) and showed that the glycan at MOG N60 modulates autoantibody binding. Experimental autoimmune encephalomyelitis (EAE) recapitulated a subset of the age-associated glycosite changes, revealing shared glycosylation signatures between aging and autoimmune targeting of MOG. Together, these findings reveal site-specific N-glycosylation as both a marker of age and a regulator of molecular interactions.

neuroscience↗

bioRxiv2026

Sexual reproduction impacts vertebrate organ aging

Sexual reproduction is a central component of life. Yet, an unanswered question remains: how does sexual reproduction shape physiology and health across an individual's lifetime? Unlike other external factors such as diet and exercise, the impact of sexual reproduction on organ health during aging is far less studied, particularly in vertebrates. Here, we develop the short-lived killifish as a vertebrate model to study how lifelong mating affects organ aging. We discover that mating regulates liver aging in a cell-type and sex-specific manner. In old female livers, mating dampened hepatocyte inflammation and reduced myeloid cell levels, and machine-learning models predicted that mating led to a 'younger' transcriptomic age in several liver cell types. Functionally, mating reduced hepatic accumulation of several lipid classes and was associated with enhanced female resilience against the liver toxin acetaminophen. More broadly, mating induced anti-inflammatory and metabolic rewiring transcriptomic signatures in the brain and gut, indicating that mating may affect vertebrate organ aging more globally. Using publicly available human datasets and plasma proteomics aging clocks, we observed an association between sexual experience and a 'younger' plasma proteomic age of several cell types, including hepatocytes. Our work provides evidence that lifelong mating reshapes the physiological context during aging in a vertebrate, highlighting an understudied connection between vertebrate sexual history, health, and aging.

genomics↗

bioRxiv2026

Sex-divergent responses to microglial depletion suggest distinct regulatory dependencies in the aged brain

Microglia are essential for brain homeostasis, yet their roles in the aged brain remain poorly defined. Using microRNA (miRNA) profiling, cellular-resolution spatial transcriptomics, and bulk proteomics in 21-month-old mice, we characterize sex-dimorphic responses to microglial depletion via CSF1R inhibition (PLX5622 treatment). Microglia-enriched miRNAs, notably miR-146a-5p and miR-223-3p, were downregulated across different brain regions in both sexes. Transcriptional responses were sex dimorphic: females showed predominantly cell-type-specific downregulation, while males showed bidirectional changes including upregulation of Lzts3, Shank3, and Fgfbp1 alongside downregulation of Ang. Proteomic changes were larger in magnitude and independent from mRNA changes: males exhibited 295 differentially expressed proteins (DEPs) versus 34 in females (8.7-fold difference). Male DEPs had opposing directional shifts in synaptic vesicle proteins (upregulated) and mitochondrial ATP synthesis machinery (downregulated). These data describe sex-dimorphic molecular consequences of microglial loss in the aged brain and identify candidate post-transcriptional mechanisms warranting further investigation.

neuroscience↗

bioRxiv2026

Unlocking Sensitive Data with SPHERE in the Age of AI

Sensitive human data underpin discoveries across medicine, biology and the social sciences, yet privacy regulation often prevents sharing them with collaborators or artificial intelligence (AI) systems. We introduce SPHERE, a model-free method that makes sensitive datasets directly usable by AI and shareable for open science as a synthetic twin, while the original records never leave the local environment. Across 33 datasets spanning five scientific domains, SPHERE protects individual privacy against adversarial re-identification attacks while preserving the data's statistical structure: means, variances and correlations are reproduced exactly, effect size and P value in linear statistical analysis is numerically identical, nonlinear machine-learning utility is retained, and each twin is generated in seconds on a laptop. Frontier AI agents running on the twin reach the same scientific conclusions as on the original records. Analyses of the twin reproduce genome- and proteome-wide results at UK Biobank scale and recover the findings of landmark studies across three independent cohorts and consortia. The approach also extends to deep-learning embeddings across language, vision and time-series, with minimal utility loss. We make the Stanford Alzheimer's Disease Research Center cohort openly available for the first time, as a SPHERE twin spanning nine modalities that any registered researcher can analyze without an approval process. We release SPHERE with certification of each twin's privacy and fidelity, and an AI agent that autonomously executes research tasks on sensitive data without ever accessing it. Sensitive datasets that are currently closed to research could thus become routine inputs to open science and AI to enable key discoveries.

bioinformatics↗

bioRxiv2026

Domain-specific proteome remodeling defines mouse myelin aging

Myelin, once regarded as a static insulating structure, is now recognized as a dynamic component of the nervous system, capable of remodeling in response to experience. Its breakdown is linked to cognitive decline and neurodegenerative diseases, often preceding neuronal dysfunction. While the myelin proteome has been studied, the age- and sex-related changes it undergoes remain poorly understood. In this study, we purified myelin proteins from young, middle-aged, and aged male and female mice. Using mass spectrometry-based proteomics, we identified 4,095 unique proteins in males and 3,931 in females, with roughly 30% showing significant age-related changes in both sexes. We find an age-related increase in compact myelin structural proteins, such as MBP, MOBP, and CLDN11, and a selective vulnerability in non-compact myelin cytoskeletal proteins, such as SEPTIN2, SEPTIN8, and OPALIN. Notably, disease-associated proteins previously characterized in single-cell transcriptomics appear at the protein level in aged myelin. To firmly distinguish between proteins derived from oligodendrocytes and other cell types in vivo we labeled nascent oligodendrocyte proteins with bio-orthogonal non-canonical amino acid tagging (BONCAT). We discovered a dramatic age-related increase in lysosomal and vesicle-associated proteins, while translation and synaptic proteins decrease in myelin with age in both sexes. This dataset highlights molecular mechanisms underlying the loss of myelin integrity and function with age and provides a novel tool for studying oligodendrocyte-derived nascent proteins in vivo.

neuroscience↗

bioRxiv2026

Plasma proteomics reveals divergent sex-specific senescence and bone biology signatures across neurodegenerative diseases

Neurodegenerative diseases are often accompanied by systemic comorbidities, including changes in bone health, but the molecular relationship between neurodegeneration, skeletal decline, and cellular senescence remains poorly understood. In this study, we investigated sex-specific changes in circulating bone- and senescence-related proteins across the spectrum of Alzheimers disease(AD), Lewbody dementia(LB) and Parkinsons disease(PD). Plasma proteomic profiling was performed on samples from 408 participants deeply phenotyped for neurodegenerative diseases, followed by differential protein and pathway analyses. This study reveals sex-dependent alterations in bone and senescence-related circulating proteins in AD-related, PD and LB-related neurodegenerative diseases, providing insights into the complex relationship between neurodegeneration and bone health. Several candidate proteins were also associated with established plasma neurodegeneration biomarkers, particularly pTau181. Pathway analyses revealed shared mitochondrial and metabolic dysfunction across neurodegenerative diseases, with disease-specific features including vesicle trafficking disruption in AD and inflammatory-senescence pathways in LB, plus sex-divergent patterns in inflammatory signaling and bone-related pathways.

neuroscience↗

bioRxiv2026

Engulfment by brain macrophages in a short-lived vertebrate

Engulfment by macrophages is critical for waste clearance in the vertebrate brain. Understanding clearance mechanisms may open new therapeutic possibilities to counter brain aging and neurodegenerative diseases. However, few in vivo models exist to study engulfment in the brain and characterize this process during aging and across species. Here we present a genetic model for secretion of a fluorescent protein by neurons in the brain of the African turquoise killifish, the shortest-lived vertebrate that can be bred in captivity. We use this model to identify a population of brain macrophages in the killifish responsible for engulfment of material from the brain extracellular space. Intriguingly, many of these cells bear similarities to mammalian border-associated and monocyte-derived macrophages, rare subsets of macrophages in mouse and human brains noted for their engulfment capabilities. We also find that in our model, killifish brain macrophages decline in engulfment capacity with age. This work highlights how vertebrate brain macrophages, particularly those at brain border regions, can play a critical role in clearance and provides an opportunity to test interventions that can boost engulfment by these macrophages to promote brain resilience in old age and disease.

cell biology↗

bioRxiv2026

Mucin-binding protein shuttles enable delivery of brain-targeted therapeutics

The blood-brain barrier (BBB) poses a major obstacle to the delivery of therapeutics into the central nervous system (CNS) due to its highly restrictive permeability. Here, we introduce glycan-targeted delivery vehicles, or GlycoShuttles, that traverse the BBB by harnessing the cerebrovascular glycocalyx, a carbohydrate-rich layer lining the BBB lumen. We discover that mucin-domain glycoproteins within this structure serve as novel entry portals for brain delivery and engineer mucin-binding protein shuttles that enable efficient transport of diverse molecular cargo across the BBB into multiple key brain cell types. This modular platform facilitates enhanced brain delivery of a variety of payloads, including antibodies and lysosomal proteins, and demonstrates therapeutic efficacy in mouse models of dementia. Our findings establish mucin-targeted GlycoShuttles as a versatile platform for noninvasive brain delivery of therapeutics, opening new avenues for the treatment of CNS diseases.

neuroscience↗

bioRxiv2026

Blood-brain barrier dysfunction predicts cognitive trajectory after ischemic stroke

Ischemic stroke doubles the risk of dementia.1-4 Stroke severity and location affect cognition early,5,6 but late dementia risk is not related to infarct characteristics, nor is it reduced by preventing additional strokes,3,6,7 and its mechanism is unknown. We identified a plasma proteomic signature of chronic stroke that was consistent with blood-brain barrier (BBB) dysfunction, including a 58% decrease in plasma levels of platelet-derived growth factor B and downregulation of its pathway compared to healthy controls. During 2 years of follow-up, the stroke-specific proteome was accentuated in stroke survivors who subsequently declined in the processing speed/executive function cognitive domain. To test BBB function, we performed dynamic contrast-enhanced MRI 6-9 months after stroke in an additional cohort and found 1.7-fold higher whole brain BBB leakage compared to controls. Finally, we compared autopsy tissue from people with infarcts and dementia at death to those with infarcts and no dementia. Those who died with dementia had dramatic loss of vascular mural cell coverage compared to those without dementia (median 0.7% vs. 27%). Thus, our proteomic, functional, and structural data implicate chronic BBB dysfunction in cognitive decline late after stroke, revealing potential proteomic and imaging biomarkers and, importantly, a novel target for intervention.

neuroscience↗

bioRxiv2026

Cellular Aging Signatures in the Plasma Proteome Record Human Health and Disease

Aging is asynchronous across cells and organs, but whether plasma proteins can capture cell type-specific aging and predict disease and mortality remains unknown. We developed machine learning models to estimate the biological age of more than 40 distinct cell types--spanning neuronal, immune, glial, endocrine, epithelial, and musculoskeletal origins--using over 7,000 plasma proteins measured in 60,000 individuals across three cohorts, comprising the largest human plasma proteomics aging study to date. Individuals showed heterogeneous aging profiles, with 20-25% exhibiting accelerated aging in a single cell type and 1-3% across ten or more cell types. APOE genotype showed antagonistic aging effects in different cell types: APOE4 carriers exhibited older astrocytes but younger macrophages, while APOE2 carriers showed the inverse. Cellular aging signatures were uniquely associated with disease status and predicted incident disease and mortality over 15 years of follow-up. Amyotrophic lateral sclerosis (ALS) showed the strongest association with skeletal myocyte aging (hazard ratio = 12.7 for extreme accelerated versus youthful aging). In Alzheimers disease (AD), prevalent cases showed accelerated aging across multiple neural and peripheral cell types, with extreme astrocyte aging conferring AD risk comparable to APOE4 carrier status. Moreover, extreme astrocyte aging increased AD risk in APOE4/4 carriers threefold, while youthful astrocytes strikingly reduced risk. Beyond neurodegeneration, respiratory cell aging identified smokers at 58% higher lung cancer risk, and myeloid aging identified normoglycemic individuals at higher diabetes risk. Both specific cellular vulnerabilities and cumulative aging burden influenced survival, wherein youthful immune or neuronal profiles were protective. A polycellular aging risk score provided robust mortality risk stratification across platforms and cohorts. These findings establish a framework for quantifying biological aging at the cellular resolution using plasma proteomics, revealing heterogeneity in aging trajectories and their impact on disease susceptibility and resilience.

neuroscience↗

bioRxiv2025

Multi-modal choroid plexus pathology in aging and Alzheimer's disease

Brain barriers, cerebrospinal fluid (CSF) dynamics, and peripheral factors are implicated as significant contributors to Alzheimers disease (AD). The choroid plexus (ChP) is a blood-brain interface that produces CSF and forms the blood-CSF barrier. However, how ChP pathology develops across the lifespan and contributes to AD has not been systematically characterized. Here, we report a multi-modal ChP atlas integrating single-nucleus transcriptomics from 49 individuals, AI-assisted quantitative histopathology across >500 postmortem samples age 16 to 105, spatial transcriptomics, and functional studies in 5xFAD mice. We identify fibrosis, calcification, and macrophage abnormalities as hallmarks of ChP aging, with AD pathology conferring additional effects, including expansion of a pro-inflammatory fibroblast-macrophage signaling niche. In 5xFAD mice, macrophage dysfunction is associated with impaired epithelial barrier maintenance and repair. Together, these data provide a foundational resource for understanding ChP dysfunction in aging and AD and propose the macrophage-fibroblast-epithelial barrier axis as a driver of ChP pathology.

neuroscience↗

bioRxiv2025

Cross-Species Transcriptomic Integration Reveals a Conserved, MIRO1-Mediated Macrophage-to-T Cell Signaling Axis Driving Immunosuppression in Glioma

Mitochondrial regulators are increasingly recognized for their influence on immune signaling within the tumor microenvironment (TME). In glioma, where immunosuppression limits therapeutic efficacy, we investigate how targeting the mitochondrial protein MIRO1 alters the TME. We combine single-nucleus RNA sequencing of murine gliomas treated in vivo with a MIRO1-binding compound and bulk RNA sequencing of human glioma resections treated with the same compound ex vivo. Cross-species transcriptomic integration reveals a MIRO1-responsive program in the TME. Among shared targets, we identify PARP11/Parp11 as a consistently upregulated gene in glioma that is downregulated following MIRO1-binding compound treatment in both human and mouse gliomas. Cell-cell communication analysis shows that a specific cluster of macrophages (MAC1), which exhibits robust Parp11 and Pdl1 (encoding PD-L1) expression, sends immunosuppressive signals to CD8+ cytotoxic T cells, and may receive prostaglandin E{square} signals from another cluster of macrophages (MAC4). Targeting MIRO1 eliminates this cell circuitry and reduces the tumor cell population. Our study provides a transcriptomic framework for understanding mitochondria-immune crosstalk and nominates MIRO1-PARP11 as a potential effector axis of brain immune dysfunction. Summary BlurbTranscriptomic integration of single-nucleus RNA sequencing of murine gliomas and bulk RNA sequencing of human gliomas reveals an immunosuppressive signaling axis in the glioma TME, mediated by MIRO1.

cancer biology↗

bioRxiv2025

Core Activation Program and Selective Regional Responsiveness of Microglia in Aging and Parabiosis

Aging is associated with immune dysregulation in brain and is the biggest risk factor for many neurodegenerative diseases whereas rejuvenation interventions can mediate beneficial effects. Microglia are considered as a major player in the development of neurodegenerative disease yet, the molecular changes underlying brain aging and rejuvenation remain poorly understood at the single cell level. We identified and benchmarked several reproducible microglial states and a core set of genes leading to microglia activation in the mice brain. We investigated microglial heterogeneity and studied the impact of aging and parabiosis-mediated exposure of young and old blood on microglia subpopulations across four different brain regions including cerebellum, cortex, hippocampus, and striatum. We revealed region-specific differences in microglia subpopulation composition and age-related changes, with cerebellum and striatum displaying the most distinctive profiles and dynamic shifts compared to other brain regions. We consistently observed cerebellum as the most responsive, while striatum appeared distinctive by its minimal responsiveness to these interventions. Our findings highlighted the role of microglia in brain regional vulnerability and provided a foundation for microglia-targeted treatment for modulating brain aging. HighlightsO_LIDefined the composition of different microglial populations reproducible in aging and parabiosis, benchmarking a reference for the field. C_LIO_LIUncovered an under-appreciated core activation gene signature of microglia shared in all reactive states and regions during normal aging and old blood-induced aging. C_LIO_LIIdentified region-specific gene expression changes and associated biological processes in microglia during aging and parabiosis C_LIO_LIDiscovered microglial regional selectivity in response to aging and parabiosis, showing cerebellum as the most sensitive region and the striatum as the least affected. C_LI

neuroscience↗

bioRxiv2025

Age-related microbiome metabolites modulate splicing and chromatin accessibility in the brain

The gut microbiome generates diverse metabolites that can enter the bloodstream and alter host biology, including brain function. Hundreds of physiologically relevant, gut-brain signaling molecules likely exist; however, there has been no systematic, high-throughput effort to identify and validate them. Here, we integrate computational, in vitro, and in vivo approaches to pinpoint microbiome-derived metabolites whose blood levels change during aging, and that induce molecular changes in the mouse brain. First, we mine large-scale metabolomics datasets from human cohorts (each n [≥] 1200) to identify 30 microbiome-associated metabolites whose blood levels change with age. We then screen this panel in an in vitro transcriptomic assay to identify metabolites that perturb genes linked to age-related neurodegeneration. To assess in vivo relevance, we then test four metabolites in male mice by acute exposure, using multi-omic approaches to evaluate the metabolites impact on cellular functions in the brain. With RNA-seq, we confirm known effects of trimethylamine N-oxide (TMAO), including changes in mitochondrial pathways, and further discover its effects on the pathways of glycolysis, GABAergic signaling, and RNA splicing. Additionally, using both RNA- and ATAC-seq, we identify glycodeoxycholate (GDCA), a microbiome-derived secondary bile acid, as a potent regulator of chromatin accessibility and of genes involved in protecting the brain from age-related stressors. GDCA also acutely reduces locomotion in male but not female mice. In summary, we present a generalizable framework for identifying microbiome metabolites that impact host biology, and apply it to identify age-related microbial metabolites that affect processes related to brain aging and neurodegeneration.

neuroscience↗

bioRxiv2025

Angiopoietin signalling is a central axis of amyloid-driven vascular dysfunction in Alzheimer's disease

The neurovascular unit is critical for brain health, and its dysfunction has been linked to Alzheimers disease (AD). However, a cell-type-resolved understanding of how diverse vascular cells become dysfunctional and contribute to disease has been missing. Here, we applied Vessel Isolation and Nuclei Extraction for Sequencing (VINE-seq) to build a comprehensive transcriptomic atlas from 101 individuals along AD progression. Our analysis of over 842,646 parenchymal and vascular nuclei reveals that vascular dysfunction in AD is driven by transcriptional changes rather than shifts in cell proportions, with brain endothelial cells (BECs) and smooth muscle cells (SMCs) most affected. Strikingly, these molecular signatures emerge early at the mild cognitive impairment (MCI) stage, implicating vascular dysfunction early in AD pathogenesis. Stratifying by pathology reveals distinct vascular responses to {beta}-amyloid and tau: {beta}-amyloid burden primarily perturbs BECs and SMCs, while tau pathology predominantly impacts glial cells. We identify dysregulated angiopoietin signaling across multiple vascular cell types as a key axis, with antagonistic ANGPT2 in vascular cells and ANGPT1 in astrocytes becoming progressively dysregulated with AD. Together, this work provides a foundational resource that reveals early and pathology-specific pathways of vascular dysfunction in AD. Key MessagesO_LIVINE-seq analysis from 101 individuals creates a comprehensive human brain vascular atlas across Alzheimers disease (AD) progression. C_LIO_LIAD vascular dysfunction is driven by transcriptional changes rather than shifts in cell proportions, with BECs and SMCs most affected. C_LIO_LITranscriptional signatures of vascular dysfunction emerge early at the mild cognitive impairment (MCI) stage, preceding severe cognitive symptoms and aligning more closely with AD than cognitively normal individuals. C_LIO_LIA{beta} and tau associate with distinct vascular changes: A{beta} mainly perturbs endothelial and smooth muscle cells, while tau impacts microglia and astrocytes. C_LIO_LIAngiopoietin signaling (antagonistic ANGPT2 in vascular cells vs. ANGPT1 in astrocytes) becomes progressively dysregulated during AD progression. C_LI

neuroscience↗

bioRxiv2025

Characterizing Post-Mortem Brain Molecular Taxonomy of Cognitive Resilience and Translating it to Living Humans

Here, we define cognitive resilience as slower or faster cognitive decline after we regress out the effects of common brain neuropathologies. Its understanding could provide important insights into the biology underlying cognitive health, enabling the development of more effective strategies to prevent cognitive decline and dementia. However, this requires the development of a practical method to quantify resilience and measure it in living individuals, as well as identifying heterogenous pathways associated with resilience in different individuals. Here, we approach this problem by using a data-driven framework to quantify and characterize molecular signatures underlying cognitive resilience. Using multimodal contrastive trajectory inference (mcTI) on bulk RNA sequencing and tandem mass tag (TMT) proteomic data from 898 post- mortem brain samples from the Religious Orders Study and the Rush Memory and Aging Project (ROSMAP), we derived individual-level molecular pseudotime values reflecting the molecular path from high to low resilience across individuals. Additionally, we identified two distinct molecular subtypes of resilience, each characterized by unique transcriptomic and proteomic signatures, and differing associations with several phenotypes. To translate our brain-derived pseudotime and subtypes to living individuals, we developed prediction models with paired genetics, ante-mortem blood omics, clinical, psychosocial, imaging and device data from the same individuals, demonstrating the potential to predict brain molecular resilience profiles in living persons. Our findings establish a framework for quantifying resilience based on multi- level molecular signatures, identify molecularly distinct resilience subtypes, and demonstrate the feasibility of translating brain-derived molecular profiles to living individuals--laying the groundwork for the development of targeted resilience-promoting interventions in cognitive aging.

neuroscience↗

bioRxiv2025

Defined human tri-lineage brain microtissues

Microglia are the immune cells of the central nervous system and are thought to be key players in both physiological and disease conditions. Several microglial features are poorly conserved between mice and human, such as the function of the neurodegeneration-associated immune receptor Trem2. Induced pluripotent stem cell (iPSC)-derived microglia offer a powerful opportunity to generate and study human microglia. However, human iPSC-derived microglia often exhibit activated phenotypes in vitro, and assessing their impact on other brain cell types remains challenging due to limitations in current co-culture systems. Here, we developed fully defined brain microtissues, composed of human iPSC-derived neurons, astrocytes, and microglia, co-cultured in 2D or 3D formats. Our microtissues are stable and self-sufficient over time, requiring no exogenous cytokines or growth factors. All three cell types exhibit morphologies characteristic of their in vivo environment and show functional properties. Co-cultured microglia develop more homeostatic phenotypes compared to microglia exposed to exogenous cytokines. Hence, these tri-cultures provide a unique approach to investigate cell-cell interactions between brain cell types. We found that astrocytes and not neurons are sufficient for microglial survival and maturation, and that astrocyte-derived M-CSF is essential for microglial survival. Single-cell and single-nucleus RNA sequencing analyses nominated a network of reciprocal communication between cell types. Brain microtissues faithfully recapitulated pathogenic -synuclein seeding and aggregation, suggesting their usefulness as human cell models to study not only normal but also pathological cell biological processes.

neuroscience↗

bioRxiv2025

Blockade of VCAM1 or VLA4 preserves cerebrovasculature and prevents cognitive decline late after stroke

Infarct-induced neurodegeneration occurs chronically after stroke, doubling the risk of dementia. Endothelial vascular cell adhesion molecule 1 (VCAM1) facilitates blood-brain barrier opening and immune cell diapedesis by binding very late antigen 4 (VLA4) on immune cells. We hypothesized that vascular dysfunction persists after stroke and contributes to chronic neuroinflammation and cognitive decline via signaling through the VLA4/VCAM1 axis. We used adult (3-5 month old) and middle-aged (10 month old) C57BL/6J male & female mice and a permanent middle cerebral artery occlusion stroke model. Sham surgery consisted of an identical procedure without occlusion of the artery. We quantified vascular integrity using blood vessel length, pericyte coverage of vasculature, tight junctions, and extravascular fibrinogen leakage by immunostaining. Cognitive testing was performed using both Barnes maze and novel object recognition prior to stroke, and 1 and 6 weeks after stroke, and replicated in both male and female mice. We utilized anti-VCAM1, anti-VLA4 or isotype control antibodies to block VCAM1 or VLA4 function, and then to confirm mechanisms we utilized single cell RNA sequencing on immune and endothelial cells, aptamer-based plasma proteomics, and additional immunostaining for vascular integrity. Mouse brains exhibited signs of persistent vascular dysfunction and loss of blood-brain barrier integrity at 8 weeks after stroke, compared to sham animals. We observed reduced ZO-1 tight junction and pericyte coverage of vasculature, and increased extravascular fibrinogen. Mice with stroke also developed a cognitive deficit in both Barnes maze and novel object by 6 weeks. Treatment with anti-VCAM1 or anti-VLA4 resulted in mice with stroke performing as well as sham mice treated with isotype control antibody on both the Barnes maze and novel object recognition tasks. Anti-VCAM1 and anti-VLA4 both increased expression of blood-brain barrier maintenance genes in brain endothelial cells, while only minimally altering immune cell gene expression. Immune cell infiltration was reduced by anti-VCAM1 but not anti-VLA4 in tissue sections. In contrast to this, both antibodies increased blood vessel length and pericyte vascular coverage. Finally, extravascular fibrinogen was reduced by both antibody treatments in multiple brain regions. Together, our findings establish the VLA4/VCAM1 axis as a promising target to preserve vascular integrity and prevent cognitive decline late after stroke. Our data is consistent with a model where blocking either VCAM1 or VLA4 chronically after stroke promotes new blood vessel growth and maturation and restores the blood-brain barrier to prevent infarct-induced neurodegeneration.

neuroscience↗