Cited by 213Single-cell and spatial transcriptomicsGenetics, Aging, and Longevity in Model OrganismsNeuroinflammation and Neurodegeneration Mechanisms

Atlas of the aging mouse brain reveals white matter as vulnerable foci

Open access
Hahn, Oliver, Foltz, Aulden G., Atkins, Micaiah, Kedir, Blen, Moran-Losada, Patricia, Guldner, Ian H., Munson, Christy, Kern, Fabian +11 more·2023·Cell

Published version of a preprint

Abstract

Summary: Aging is the key risk factor for cognitive decline, yet the molecular changes underlying brain aging remain poorly understood. Here, we conducted spatiotemporal RNA-seq of the mouse brain, profiling 1,076 samples from 15 regions across 7 ages and 2 rejuvenation interventions. Our analysis identified a brain-wide gene signature of aging in glial cells, which exhibited spatially defined changes in magnitude. By integrating spatial and single-nucleus transcriptomics, we found that glia aging was particularly accelerated in white matter compared to cortical regions, while specialized neuronal populations showed region-specific expression changes. Rejuvenation interventions, including young plasma injection and dietary restriction, exhibited distinct effects on gene expression in specific brain regions. Furthermore, we discovered differential gene expression patterns associated with three human neurodegenerative diseases, highlighting the importance of regional aging as a potential modulator of disease. Our findings identify molecular foci of brain aging, providing a foundation to target age-related cognitive decline.

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Written from the paper’s full text.

TL;DR

This study maps spatiotemporal transcriptomic aging across the mouse brain and finds that white matter tracts, especially the corpus callosum, are foci of accelerated aging. A common 82-gene aging signature is largely driven by glial and endothelial cells, while region-specific neuronal signatures and disease-associated genes show regional vulnerability.

Key findings

  • Across 847 bulk, 16,277 spatial spot, and 81,616 single-cell/nuclei transcriptomes from 15 brain regions and 7 ages, aging effects were highly region- and time-dependent; the entorhinal cortex had only 13 detectable DEGs, whereas white matter-rich regions such as corpus callosum, cerebellum, and caudate putamen were most affected.
  • An 82-gene common aging score (CAS) was defined from genes changing in ≥10 of 14 regions; the corpus callosum had the fastest CAS velocity, while cortical areas and olfactory bulb ranked last at approximately one-third of that velocity.
  • CAS increases were most pronounced in microglia, followed by mature oligodendrocytes, brain endothelial cells, astrocytes, and OPCs; microglia from cerebellum and striatum showed greater CAS increases than those from hippocampus and cortex.
  • Region-specific aging signatures were largely encoded by neuronal subpopulations, and human GWAS genes for multiple sclerosis, Alzheimer’s disease, and Parkinson’s disease showed distinct region-selective enrichment patterns.

Methods

  • Bulk RNA-seq was performed on 15 punched brain regions from left/right hemispheres of C57BL/6JN mice across ages 3–28 months, yielding 847 single-region transcriptomes after QC; spatial transcriptomics was performed on coronal sections from an independent male cohort at 6, 18, and 21 months.
  • Single-nuclei RNA-seq was performed on anterior hippocampus and caudate putamen from the same bulk-seq cohort at 3 and 21 months, and public scRNA-seq datasets were reanalyzed.
  • Analyses included DESeq2 differential expression, Spearman age correlation, WGCNA, VISION-based gene signature scores, linear models for CAS velocity, and MAST for single-cell differential expression.

Limitations

  • The paper states that it cannot predict whether the directionality of disease-associated gene regulation has a biological consequence, that the substantia nigra was not quantified, and that spatial-seq and single-cell CAS analyses treat spots/cells as replicates rather than accounting for biological replicates.
  • The paper notes that requiring significance in at least two pairwise comparisons selects against genes differentially expressed very late in life, and that very low aNSC numbers at 28 months complicate robust CAS calculations.
  • Evident from the text: findings are from mouse brain and rely on bulk tissue punches, spatial spots, and nuclei/cell suspensions, with limited direct human validation.

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Integrity signals

Registry

Crossref · 10.1016/j.cell.2023.07.027

Cites

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Statistics

Nothing to recompute.

Claims the paper makes

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  • Findingown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    The corpus callosum-derived signature demarcated fiber tracts throughout the brain.

    “Notably, the corpus callosum-derived signature demarcated fiber tracts throughout the brain, indicating that the sampled transcriptome of this region could be a proxy for white matter tracts in general (Figure S3A).”
    Quote in the paperSubstantial claim
  • Findingown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    Region-enriched gene signature scores were distinctly elevated in areas corresponding to anatomical structures annotated in the Allen brain reference atlas.

    “Signature scores were distinctly elevated in areas corresponding to the anatomical structures annotated in the Allen brain reference atlas (Figure S3A) (Lein et al., 2007).”
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    • cites Lein et al., 2007 source

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  • Findingown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    Within individual regions, samples segregated transcriptionally by age.

    “However, within individual regions, samples segregated transcriptionally by age.”
    Quote in the paperSubstantial claim
  • Findingown data
    § Region identity is linked to expression dynamics during aging

    There is substantial region-dependence in the magnitude and timing of C4b expression.

    “For instance, we found substantial region-dependence in the magnitude and timing of C4b expression (Figure 1E), a complement component and major schizophrenia risk factor (Sekar et al., 2016) that is robustly up-regulated in aged mice (Hahn et al., 2020) and models of neurodegeneration (Zhou et al., 2020).”
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    • cites Sekar et al., 2016 source

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    • cites Hahn et al., 2020

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  • Findingown data
    § Neuronal transcripts encode region-specific expression patterns

    Expression of Chrm3 dropped significantly in the caudate putamen, reflecting down-regulation specifically in D2 MSNs.

    “For instance, expression of muscarinic acetylcholine receptor gene Chrm3 dropped significantly in the caudate putamen, reflecting down-regulation of this gene specifically in D2 MSNs (Figure 5I,J).”
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    Findingown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    UMAP visualization separated samples by region, but not by sex or age.

    “Visualization in uniform manifold approximation and projection (UMAP) space separated samples by region (Figure 1C), but not sex or age, which concurred with deterministic shared-nearest-neighbors graph clustering and hierarchical clustering (Figure S2A-E).”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Heterogeneous velocity of CAS is encoded by glial transcripts

    There was a profound increase of CAS in aNSCs, though the very low number of cells at 28 months complicates robust calculations of CAS at this age.

    “There was also a profound increase of CAS in aNSCs, though the very low number of cells at 28 months (less than 50 per animal) complicates robust calculations of CAS at this age.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Transcriptional aging of microglia is region-dependent

    In aged microglia from the Tabula Muris consortium, CAS increased significantly in all four regions (cerebellum, striatum, hippocampus, cortex), with greater magnitude in cerebellum and striatum, followed by hippocampus and cortex.

    “Indeed, as predicted by our bulk-seq results, the CAS in aged microglia increased in all four regions significantly, though with greater magnitude in the cerebellum and striatum, followed by the hippocampus and cortex, respectively (Figure 4B).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Microglia from the Tabula Muris consortium collected from cerebellum, striatum, hippocampus and cortex are sufficient equivalents to the authors' cerebellum, caudate putamen, anterior hippocampus and motor/visual cortex regions.
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    Findingown data
    § A minimal gene set forms a common fingerprint of brain aging

    Other white matter-rich areas such as the caudate putamen also exhibited high CAS velocities, while the hippocampus, thalamus and hypothalamus ranked slightly below average.

    “Other white matter-rich areas such as the caudate putamen also exhibited high velocities, while the hippocampus, thalamus and hypothalamus - some of the most investigated regions in mouse and human brain aging research (Hargis and Blalock, 2017) - ranked slightly below average.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Hargis and Blalock, 2017

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    Findingown data
    § Neuronal transcripts encode region-specific expression patterns

    Several signature genes like Fgf16, S100a10 and Fabp4 were mapped to distinct cell populations, suggesting that bulk tissue can capture the expression dynamics of specific cell subsets.

    “We were able to map several signature genes like Fgf16 , S100a10 and Fabp4 (Figure S10C-E) to distinct cell populations (Figure 5G, STAR Methods and Table S9) suggesting that bulk tissue can indeed capture the expression dynamics of specific cell subsets.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Region identity is linked to expression dynamics during aging

    The visual cortex showed a steady increase of DEGs until late age, while the motor cortex exhibited significant perturbation at 12 months with little increase until a sudden jump at 21 months.

    “For instance, the visual cortex showed a steady increase of DEGs until late age, while the transcriptome of the motor cortex already exhibited significant perturbation at 12 months, but there was little increase until a sudden jump at 21 months (Figure 1F,G).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Aging results in region-specific expression changes of genes associated with human diseases

    The visual and motor cortex regions formed the second cluster, exhibiting even numbers of up- and down-regulated MS genes.

    “The visual and motor cortex regions formed the second cluster, exhibiting even numbers of upand down-regulated MS genes.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Neuronal transcripts encode region-specific expression patterns

    Dentate gyrus granule cells of the hippocampus exhibited a distinct increase of the hippocampus-specific signature, and granule cell-specific regulation of several signature genes such as Unc5d and Onecut1 was found.

    “In comparison, dentate gyrus granule cells of the hippocampus exhibited a distinct increase of the hippocampusspecific signature (Figure 5K), and we found granule cell-specific regulation of several signature genes such as axon-guidance receptor Unc5d (Yamagishi et al., 2011) as well as transcription factor Onecut1 (Figure 5L,M, Figure S11A,B).”
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    Findingcitation
    § Region identity is linked to expression dynamics during aging

    A small, common set of differentially regulated genes, including neuroinflammatory markers Fcgr2b, Ctss, Cst7, was found in modules across regions, suggesting the presence of a minimal group of coregulated genes changing throughout the brain.

    “Consistent with these findings, we found a small, common set of differentially regulated genes, including neuroinflammatory markers Fcgr2b , Ctss , Cst7 (Chen et al., 2020) in modules across regions, suggesting the presence of a minimal group of coregulated genes changing throughout the brain.”
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    • cites Chen et al., 2020 source

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    Findingown data
    § Aging results in region-specific expression changes of genes associated with human diseases

    MS genes showed significant associations with DEGs from nine different regions that fell into two clusters, indicating two disparate subsets.

    “MS genes, for instance, showed significant associations with DEGs from nine different regions that fell into two clusters, indicating two disparate subsets.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Region identity is linked to expression dynamics during aging

    The corpus callosum and cerebellum were the most impacted by age-correlated gene expression changes, while the entorhinal cortex remained largely unaffected.

    “Not only did the regions differ in the number of age-correlated genes, confirming that the effect size of age depends on the region, but also the corpus callosum and cerebellum were the most impacted, while the entorhinal cortex remained largely unaffected (Figure 1H).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Fiber tracts are foci of accelerated brain aging

    CAS velocities calculated via bulk-seq and those calculated via spatial-seq data were well-correlated, confirming vastly differing aging velocities between proximal regions in situ.

    “In general, CAS velocities calculated via bulk-seq and those calculated via spatial-seq data were well-correlated (Figure 2P), confirming vastly differing aging velocities between proximal regions in-situ .”
    Quote in the paperSubstantial claim
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    Findingown data
    § Heterogeneous velocity of CAS is encoded by glial transcripts

    C4b was mostly expressed in astrocytes at young age, but its expression became detectable and increased foremost with age in mature oligodendrocytes.

    “For instance, C4b was mostly expressed in astrocytes at young age, however its expression became detectable and increased foremost with age in mature oligodendrocytes (Figure S6E).”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Region identity is linked to expression dynamics during aging

    The number of age-related WGCNA modules differed between regions, with seven or more modules in the corpus callosum, cerebellum and motor cortex, and no age-related modules in the entorhinal cortex.

    “In line with the above results, we found seven or more modules in the corpus callosum, cerebellum and motor cortex, whereas we detected no agerelated modules in the entorhinal cortex (Table S4).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Heterogeneous velocity of CAS is encoded by glial transcripts

    CAS showed a statistically significant increase in all cell types, with the most accentuated increase in microglia, followed by mature oligodendrocytes, BECs, astrocytes and OPCs.

    “While the CAS showed a statistically significant increase in all cell types (Figure 3B), including a mild elevation in several neuronal populations, the most accentuated increase was observed in microglia (Figure 3C), followed by mature oligodendrocytes, brain endothelial cells (BECs), astrocytes and oligodendrocyte progenitor cells (OPCs).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Transcriptional aging of microglia is region-dependent

    There was no detectable CAS difference among microglia at young age across the striatum, hippocampus and cortex, while cerebellum-derived microglia exhibited a slightly higher CAS at baseline.

    “Notably, there was no detectable CAS difference among microglia at young age across the striatum, hippocampus and cortex, while the cerebellumderived microglia exhibited a slightly higher CAS at baseline.”
    Quote in the paperSubstantial claim
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    Findingcitation
    § A minimal gene set forms a common fingerprint of brain aging

    Of the only 7 down-regulated genes in the 82-gene set, protein homeostasis genes Dnajb1, Hsph1 and Ahsa1, as well as collagen synthesis gene P4ha1, were found, which is in line with perturbed protein quality control mechanisms as a hallmark of aging.

    “Interestingly, of the only 7 down-regulated genes in this set, we found protein homeostasis genes Dnajb1 , Hsph1 and Ahsa1 , as well as collagen synthesis gene P4ha1 , which is in line with perturbed protein quality control mechanisms as a hallmark of aging (López-Otín et al., 2013) (Figure 2B).”
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    • cites López-Otín et al., 2013 source

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    Findingown data
    § Neuronal transcripts encode region-specific expression patterns

    There was a significant down-regulation of several mitochondria-related genes in the caudate putamen, including several members of the electron transport chain, which could be indicative of impaired mitochondrial function.

    “We observed a significant down-regulation of several mitochondria-related genes in the caudate putamen, including several members of the electron transport chain, which could be indicative of impaired mitochondrial function (Figure 5E).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Aging results in region-specific expression changes of genes associated with human diseases

    One cluster consisted of several regions, including the corpus callosum and cerebellum, that up-regulated a shared set of inflammation-related genes such as Stat3, Ly86 and Irf8, all of which were also part of the CAS.

    “One cluster consisted of several regions, including the corpus callosum and cerebellum, that up-regulated a shared set of inflammation-related genes such as Stat3 , Ly86 and Irf8 , all of which were also part of the CAS (Figure 6A).”
    Quote in the paperSubstantial claim
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    Findingown data
    § A minimal gene set forms a common fingerprint of brain aging

    The hypothalamus exhibited the most pronounced acceleration of CAS in females, with the thalamus and corpus callosum indicating a similar trend.

    “In particular, the hypothalamus exhibited the most pronounced acceleration in females (Figure S4D), with the thalamus and corpus callosum indicating a similar trend.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Aging results in region-specific expression changes of genes associated with human diseases

    Each of the three disease-associated gene sets (AD, PD, MS) exhibited a different enrichment pattern and a varying number of associated genes.

    “Interestingly, each of the three disease-associated gene sets exhibited a different enrichment pattern (Figure 6A-C) and a varying number of associated genes (Figure 6D-F).”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Heterogeneous velocity of CAS is encoded by glial transcripts

    Single-nuclei sequencing yielded all major cell types, with no evidence for a shift in cell type composition with age or sex.

    “Singlenuclei sequencing (nuc-seq) yielded all major cell types, with no evidence for a shift in cell type composition with age or sex.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Neuronal transcripts encode region-specific expression patterns

    In the caudate putamen, there was a global, gradual downregulation of all genes coding for mitochondria-related proteins, as well as a significant drop in scores for a corresponding mitochondrial signature in aged D2 MSNs, mature oligodendrocytes, and astrocytes.

    “We identified in this region a global, gradual downregulation of all genes coding for mitochondria-related proteins (Figure S11E), as well as a significant drop in scores for a corresponding mitochondrial signature in aged D2 MSNs, mature oligodendrocytes, and astrocytes (Figure S11F).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Region identity is linked to expression dynamics during aging

    The regions with the most profound and earliest shifts in gene expression were the white matter-rich caudate putamen, cerebellum and corpus callosum, with the corpus callosum showing a tenfold increase in the number of DEGs between 12 and 18 months.

    “Notably, the regions with the most profound and earliest shifts in gene expression were the white matter-rich caudate putamen, cerebellum and corpus callosum, the latter showing a tenfold increase in the number of DEGs between 12 and 18 months.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Bulk-seq GWAS gene enrichment

    The authors observed several white matter-related effects in their dataset.

    “as we had observed several white matter-related effects in our dataset.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Spatial-seq differential expression analysis and comparison with Bulk-seq data

    For both the white matter/corpus callosum and cortex/motor cortex regions, there is significant overlap between the DEGs found in the Bulk-seq and Spatial-seq datasets (Fisher's exact test, P < 0.05).

    “For both regions, we confirmed significant overlap between the DEGs found in Bulk- and Spatial-seq dataset (Fisher's exact test, P Value &lt; 0.05).”
    Quote in the paperSubstantial claim
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    Findingown data
    § Discussion

    Certain brain regions are selectively vulnerable to aging, with the white matter fiber tracts exhibiting a particular sensitivity.

    “Our data reveal that certain brain regions are selectively vulnerable to aging, with the white matter fiber tracts exhibiting a particular sensitivity.”
    Quote in the paperSubstantial claim
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    Findingown data
    § Spatial-seq mapping, embedding, clustering and region identification

    Transcriptional clustering of the spatial spot transcriptomes yielded 29 clusters.

    “Transcriptional clustering yielded 29 clusters”
    Quote in the paperNot a substantial claim
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    Findingown data
    § Bulk-seq region-specific aging signature identification and velocity comparison

    Fewer than 20 unique DEGs were found for the entorhinal cortex, which the authors considered too small to construct a signature.

    “Further, there were less than 20 unique DEGs found for the entorhinal cortex, which we considered too small to construct a signature.”
    Quote in the paperNot a substantial claim
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    Study design and conductown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    The study achieved robust tissue sampling with high RNA quality while minimizing perfusion artifacts, as indicated by consistent RNA yields across samples from the same region, median RNA integrity numbers of 9.45 out of 10, and a negligible fraction of reads mapping to hemoglobin genes.

    “We achieved robust tissue sampling with high RNA quality while minimizing perfusion artifacts, as indicated by consistent RNA yields across samples from the same region (Figure S1B), median RNA integrity numbers of 9.45 out of 10 (Figure S1C) (Mueller), and a neglectable fraction of reads mapping to hemoglobin genes (Figure S1D).”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    The comparatively subtle effect of aging on gene expression highlights the necessity for precise isolation of brain tissue to avoid confounding cross-region contamination.

    “The comparatively subtle effect of aging on gene expression highlights the necessity for precise isolation of brain tissue to avoid confounding crossregion contamination (Figure 1D and S2A).”
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    Premisecitation
    § Introduction

    Neuroimaging studies using structural and functional MRI indicate that aging impacts the brain in a region-specific manner.

    “Interestingly, neuroimaging studies using structural and functional magnetic resonance imaging (MRI) data indicate that aging impacts the brain in a region-specific manner (Feng et al., 2020; Pomponio et al., 2020).”
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    Premisecitation
    § Introduction

    Aging is the predominant risk factor for cognitive dysfunction and several neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease.

    “Aging is the predominant risk factor for cognitive dysfunction (Kalache and Gatti, 2003; Partridge et al., 2018) and several neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD) (Hou et al., 2019; López-Otín et al., 2013; Niccoli et al., 2017).”
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    • cites Kalache and Gatti, 2003

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    Premisecitation
    § Spatiotemporal quantification of age-related gene expression across the mouse brain

    Activated neural stem cells are enriched in neurogenic areas at young age and their number declines in old individuals.

    “These aNSCs are enriched in neurogenic areas at young age and their number declines in old individuals (Dulken et al., 2019).”
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    • cites Dulken et al., 2019 source

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    Interpretationreasoning
    § Neuronal transcripts encode region-specific expression patterns

    The transcriptome of neuronal populations could be regulated selectively through age-related activity of specific transcription factors.

    “This may indicate that the transcriptome of neuronal populations could be regulated selectively through age-related activity of specific transcription factors.”
    Quote in the paperNot a substantial claim
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    Interpretationown data
    § Heterogeneous velocity of CAS is encoded by glial transcripts

    Region-to-region differences in CAS velocity predominantly reflect age effects in non-neuronal cell types, with microglia having the strongest contribution.

    “Thus, the region-to-region differences in CAS velocity are predominantly reflecting age effects in non-neuronal cell types, with microglia having the strongest contribution.”
    Quote in the paperSubstantial claim
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    Study design and conductown data
    § Fiber tracts are foci of accelerated brain aging

    Spatial transcriptomics data demonstrated robust capture of the same regions across age groups and individuals, enabling comparison of DEGs found in bulk-seq with spatial-seq data.

    “Our data demonstrated robust capture of the same regions across age groups and individuals (Figure S5G-L), thus enabling the comparison of DEGs found in bulk-seq with spatial-seq data (Table S7).”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § A minimal gene set forms a common fingerprint of brain aging

    The authors' data could advance understanding of sexual dimorphisms in the brain, including the higher age-specific risk of dementia among women and the dynamics of reproductive aging.

    “Our data could advance the understanding of several sexual-dimorphisms observed in the brain, including the higher age-specific risk of dementia among women (Corrada et al., 2008) in general, and the dynamics of reproductive aging in particular, given the hypothalamus' critical role in regulating reproduction, development and metabolism (Mozhui et al., 2012).”
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    Interpretationown data
    § Neuronal transcripts encode region-specific expression patterns

    Dozens to hundreds of genes in the brain are regulated in a region-specific or -selective manner, revealing highly compartmentalized effects of aging within a single organ.

    “Thus, dozens to hundreds of genes in the brain are regulated in a region-specific or -selective manner, revealing highly compartmentalized effects of aging within a single organ.”
    Quote in the paperSubstantial claim
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    Premisecitation
    § Neuronal transcripts encode region-specific expression patterns

    Onecut transcription factors have only been recently investigated in the CNS as regulators of neuronal differentiation and their motif is a hotspot of DNA single-strand break repair in neurons.

    “Onecut transcription factors have only been recently investigated in the CNS as regulators of neuronal differentiation and their motif is a hotspot of DNA single-strand break repair in neurons (Wu et al., 2021).”
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    • cites Wu et al., 2021

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    Premisecitation
    § Region identity is linked to expression dynamics during aging

    Human MRI and microarray studies demonstrate that the entorhinal cortex displays only mild alterations during cognitively normal human aging, whereas it frequently exhibits the first amyloid deposition in AD patients.

    “This is in line with human MRI (Feng et al., 2020) and microarray (Berchtold et al., 2008) studies demonstrating that the entorhinal cortex displays only mild alterations during cognitively normal human aging, whereas it frequently exhibits the first amyloid deposition in AD patients (Van Hoesen et al., 1991).”
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    • cites Feng et al., 2020

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    Interpretationown data
    § Region identity is linked to expression dynamics during aging

    The results of three independent analyses (pairwise tests, age-correlation and WGCNA) were congruent, demonstrating that the observed effects of aging on the transcriptome are region specific.

    “In summary, we found the results of three independent analyses (pairwise tests, age-correlation and WGCNA) congruent, demonstrating that the observed effects of aging on the transcriptome are region specific.”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § Aging results in region-specific expression changes of genes associated with human diseases

    There is an intriguing possibility of similarities between the pathophysiology of inflammation and demyelination associated with MS and the accelerated aging observed in white matter-rich areas.

    “This raises the intriguing possibility of similarities between the pathophysiology of inflammation and demyelination associated with MS and the accelerated aging observed in white matter-rich areas.”
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    Premisecitation
    § A minimal gene set forms a common fingerprint of brain aging

    Human studies report more pronounced expression of immune-related genes in the hippocampus and cortex of aged women.

    “These findings are in line with human studies reporting more pronounced expression of immune-related genes in the hippocampus and cortex of aged women (Berchtold et al., 2008; Yuan et al., 2012).”
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    Study design and conductnone given
    § Bulk-seq quantification, quality control

    The quantification and smoothing of trajectories was solely used for visualization and was not the basis for any statistical testing in this study.

    “This quantification and smoothing was solely used for visualization and was not the basis for any statistical testing in this study.”
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    Premisecitation
    § Gene signature generation and score calculation

    VISION z-normalizes signature scores with random gene signatures to account for global sample-level metrics such as total number of counts/UMIs, which can be affected by age.

    “Notably, VISION znormalizes signature scores with random gene signatures to account for global sample-level metrics (such as total number of counts/UMIs, which can be affected by age (Pálovics et al., 2022)).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites DeTomaso et al., 2019

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    • cites Pálovics et al., 2022

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    Study design and conductnone given
    § Bulk-seq differential expression

    P values were adjusted for multiple testing, and genes with an adjusted P value of less than 0.05 were determined to be statistically significant.

    “P values were adjusted for multiple testing, and genes with an adjusted P value of less than 0.05 were determined to be statistically significant.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given
    § Spatial-seq CAS calculation

    The Spatial-seq CAS analysis does not account for biological replicates but treats each spot belonging to the same region as a replicate.

    “We acknowledge that this analysis does not account for biological replicates but treats each spot belonging to the same region as replicate.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Bulk-seq Common Aging Score (CAS) calculation and CAS velocity comparison

    Only the anterior hippocampus region was included in the selection of cross-region DEGs to prevent a potential bias towards aging effects in the hippocampus.

    “We included only the anterior hippocampus region in the selection of cross-region DEGs to prevent a potential bias towards aging effects in the hippocampus.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Bulk-seq differential expression

    A gene was required to reach statistical significance after multiple testing correction in at least 2 pairwise comparisons to be called a differentially expressed gene (DEG).

    “Finally, we required a gene to reach statistical significance (after multiple testing correction) in at least 2 pairwise comparisons (e.g. 3 months vs 18 months and 3 months vs 21 months) to be called a differentially expressed gene (DEG).”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Bulk-seq preparation and sequencing

    RNA quality control was conducted using a Bioanalyzer for three randomly selected samples per brain region.

    “Quality control of RNA was conducted using a Bioanalyzer (Agilent) at the Stanford Protein and Nucleic Acid Facility for three randomly selected samples per brain region.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Bulk-seq quantification, quality control

    The Seurat-based quality assessment was corroborated by loading and normalizing the count matrix using DEseq2 and conducting variance stabilizing transformation.

    “We corroborated the Seurat-based quality assessment by loading and normalizing the count matrix using DEseq2 before conducting the built-in variance stabilizing transformation”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Signature calculations in scRNA- and Nuc-seq data

    The scRNA-/Nuc-seq CAS analysis does not account for biological replicates but treats each cell belonging to the same cell type as a replicate.

    “We acknowledge that this analysis does not account for biological replicates but treats each cell belonging to the same cell type as replicate.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Gene signature generation and score calculation

    The VISION analysis workflow is applicable for bulk, spatial and single-cell/-nuclei datasets.

    “While VISION was originally intended for the analysis of signatures in single-cell data we found its analysis workflow applicable for bulk, spatial and single-cell/-nuclei datasets.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given
    § Spatial-seq differential expression analysis and comparison with Bulk-seq data

    Clusters in the Spatial-seq data are comparably represented across all samples and age groups, making differential expression analysis across age groups feasible.

    “Given comparable representation of clusters across all samples and age groups, we considered differential expression analysis across age groups feasible.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation
    § DEG Gene Ontology functional enrichment

    The set of expressed genes, defined as passing the independent filtering criterion of DEseq2, was used as background for all functional enrichment analyses involving expression data.

    “Unless stated otherwise, the set of expressed genes (defined as passing the independent filtering criterion of DEseq2 (Love et al., 2014)) was used as background for all functional enrichment analyses involving expression data.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Love et al., 2014 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § Spatial-seq mapping, embedding, clustering and region identification

    Spatial-seq clusters were annotated by comparing marker gene expression to in situ hybridization data from the Allen Mouse Brain Atlas and to visual landmarks from the H&E microscopy images.

    “We compared the expression of marker genes to insitu hybridization (ISH) data from the Allen Mouse Brain Atlas(Lein et al., 2007) and visual landmarks from the H&amp;E microscopy images”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Lein et al., 2007 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Aging results in region-specific expression changes of genes associated with human diseases

    The substantia nigra, a major region where PD typically manifests, was not quantified in this study.

    “Of note, the substantia nigra, a major region where PD typically manifests, was not quantified in our study.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation
    § Discussion

    Rejuvenation of hippocampal oligodendrogenesis in aged mice via injection of young cerebrospinal fluid improves long-term memory consolidation, demonstrating a causal role of compromised myelin on cognition.

    “In line with this hypothesis, rejuvenation of hippocampal oligodendrogenesis in aged mice via injection of young cerebrospinal fluid (CSF) improves long-term memory consolidation, thus demonstrating a causal role of compromised myelin on cognition (Iram et al., 2022).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Iram et al., 2022

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § Discussion

    The impacts of aging on brain function potentially relate to the regional vulnerability across different diseases as well as the varied manifestations of neurodegeneration at the level of an individual.

    “potentially relating to the regional vulnerability across different diseases as well as the varied manifestations of neurodegeneration at the level of an individual.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § Bulk-seq GWAS gene enrichment

    The anterior hippocampus region was chosen as representative for the hippocampus, and the entorhinal cortex and olfactory bulb were excluded.

    “We chose the anterior hippocampus region as representative for the hippocampus, and further excluded the entorhinal cortex (too few DEGs) and olfactory bulb.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Animal husbandry and organ collection

    Age groups and sexes were rotated through over the duration of the takedowns to average out the impact of takedown time.

    “Age groups and sexes were rotated through over the duration of the takedowns to average out the impact of takedown time.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § Bulk-seq correlation of gene expression with age

    Genes with Spearman's rho ≥ 0.5 or ≤ -0.5 and padj ≤ 0.05 were called significantly age-correlated in a given region.

    “Genes with Spearman's rho ≥ 0.5 or ≤ -0.5, respectively, and padj ≤ 0.05 were called as significantly age-correlated in a given region.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Bulk-seq differential expression

    Differential expression analysis comparing samples from 3 months to each consecutive time point used sex as a covariate.

    “We conducted differential expression analysis comparing samples from 3 months to each consecutive time point, using sex as covariate.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given
    § Spatial-seq differential expression analysis and comparison with Bulk-seq data

    The Spatial-seq white matter cluster is comparable to the bulk-seq corpus callosum region (high CAS velocity) and the Spatial-seq cortex cluster is comparable to the bulk-seq motor cortex region (low CAS velocity).

    “We analyzed differential expression in the white matter and cortex cluster as we considered them comparable to the corpus callosum (high CAS velocity) and motor cortex (low CAS velocity) region from the bulk-seq dataset.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning
    § Gene signature generation and score calculation

    VISION scores can be negative due to differences in baseline expression across regions or cell types and the z-normalization.

    “We note that due to differences in baseline expression across regions or cell types as well as the znormalization mentioned above, VISION scores can be negative.”
    Quote in the paperNot a substantial claim
66 of 66
  • The paper relies on this without support.

    Bulk RNA-seq data, even with regional dissection, could mask transcriptional changes with age that occur in sub-structures of regions, such as specific layers of the cortex.

    “Bulk-seq data - even with the regional dissection conducted here - could mask transcriptional changes with age that occur in sub-structures of regions, such as specific layers of the cortex.”
  • The authors state this as an assumption.

    Microglia from the Tabula Muris consortium collected from cerebellum, striatum, hippocampus and cortex are sufficient equivalents to the authors' cerebellum, caudate putamen, anterior hippocampus and motor/visual cortex regions.

    “which we considered sufficient equivalents to the cerebellum, caudate putamen (both areas with high velocity), anterior hippocampus (medium velocity) and motor/visual cortex (low velocity) regions (compare Figure 2G).”
  • The paper relies on this without support.

    Mouse brain aging findings are relevant to human brain aging and neurodegenerative disease.

    “Our findings identify molecular foci of brain aging, providing a foundation to target age-related cognitive decline.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Previously, spatial transcriptomics technology has been utilized to create spatiotemporal maps of various life stages, including mouse brain, regenerating axolotl telencephalons, aging ovary, and brain.

    “Previously, this technology has been utilized to create spatiotemporal maps of various life stages, including mouse brain, regenerating axolotl telencephalons, aging ovary, and brain.21”

    From Spatial transcriptomic landscape unveils immunoglobin-associated senescence as a hallmark of aging (2024) · cites this paper as [59]

    The Discussion (page not provided) reports a spatiotemporal map of gene expression across the mouse brain throughout adulthood, and “Fiber tracts are foci of accelerated brain aging” describes spatial transcriptomics across mouse ages. Our copy does not support the sentence’s other examples—regenerating axolotl telencephalons and aging ovary—as applications documented by this source. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • The white matter is selectively vulnerable to the aging process.

    “The white matter is selectively vulnerable to the aging process,91,92”
  • For 66 of the 82 target genes, expression values from 809 samples matching to the miRNA samples were obtained using gene data from Hahn et al.

    “Using the gene data from Hahn et al.3, we obtained for 66 of the target genes expression values from 809 samples matching to the miRNA samples.”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Caudate putamen gene named differently in text and figure legend

    Minor

    The results name Fgf16 as a gene shown in Figure S10C-E, whereas the legend identifies the gene in panel C as Fgf17.

  • Male cohort sizes disagree between figure and methods

    Minor

    Figure 1A gives a maximum of five males per age, while the animal-husbandry methods state that five to six males were used for each of the five age groups from 3 through 21 months.

  • Spatial-seq comparison cites an age that was not sampled

    Minor

    Figure 2L describes spatial-seq expression ratios for 21 months relative to 3 months, but the spatial-seq cohort had no 3-month-old mice. The methods describe the spatial-seq differential-expression comparison as 21 versus 6 months.

3 of 3

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Hahn, O., Foltz, A. G., Atkins, M., Kedir, B., Moran-Losada, P., Guldner, I. H., Munson, C., Kern, F., Pálovics, R., Lu, N., Zhang, H., Kaur, A., Hull, J., Huguenard, J. R., Grönke, S., Lehallier, B., Partridge, L., Keller, A., & Wyss-Coray, T.
Affiliations
  • Stanford Medicine (US)
  • NYU Langone Health (US)
  • Helmholtz Centre for Infection Research (DE)
  • Max Planck Institute for Biology of Ageing (DE)
  • Alkahest, Inc. (United States) (US)
Venue
Cell
Publisher
Elsevier BV
Published
2023-09
Volume
186
Issue
19
Pages
4117-4133.e22
ISSN
0092-8674 (ISSN-L)
OpenAlex
W4385880069
Cited by
213
References
92
Citations by year
2026: 66 · 2025: 92 · 2024: 45 · 2023: 10
FWCI
18.98
Type
journal article
Language
en
Open access
Locations
  • Cell (publishedVersion)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • UCL Discovery (University College London) (submittedVersion)
Funders
  • Michael J. Fox Foundation for Parkinson's Research (MJFF-021418, 125491594)
  • Simons Foundation
  • American Heart Association
  • Cure Alzheimer's Fund
  • Fondation Bertarelli
  • European Commission (2007–2013, FP7 2007-2013, FP7/2007)
  • Max-Planck-Gesellschaft
  • Wu Tsai Neurosciences Institute, Stanford University
  • National Institute on Aging (R01AG072255)
  • National Institute of Mental Health (R01MH121075)
  • FP7 Ideas: European Research Council (268739)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Single-cell and spatial transcriptomics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Aging › Genetics, Aging, and Longevity in Model Organisms
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
brain aging, white matter, single-nucleus transcriptomics, dietary restriction, neurodegenerative diseases, age-related cognitive decline, mouse brain atlas
MeSH terms
Single-Cell Gene Expression Analysis, Aging, Animals, Brain, Humans, Solitary Nucleus, Gene Expression Profiling, Mice, Cognitive Dysfunction, White Matter

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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