Abstract
Recent understanding of how the systemic environment shapes the brain throughout life has led to numerous intervention strategies to slow brain ageing1,2,3. Cerebrospinal fluid (CSF) makes up the immediate environment of brain cells, providing them with nourishing compounds4,5. We discovered that infusing young CSF directly into aged brains improves memory function. Unbiased transcriptome analysis of the hippocampus identified oligodendrocytes to be most responsive to this rejuvenated CSF environment. We further showed that young CSF boosts oligodendrocyte progenitor cell (OPC) proliferation and differentiation in the aged hippocampus and in primary OPC cultures. Using SLAMseq to metabolically label nascent mRNA, we identified serum response factor (SRF), a transcription factor that drives actin cytoskeleton rearrangement, as a mediator of OPC proliferation following exposure to young CSF. With age, SRF expression decreases in hippocampal OPCs, and the pathway is induced by acute injection with young CSF. We screened for potential SRF activators in CSF and found that fibroblast growth factor 17 (Fgf17) infusion is sufficient to induce OPC proliferation and long-term memory consolidation in aged mice while Fgf17 blockade impairs cognition in young mice. These findings demonstrate the rejuvenating power of young CSF and identify Fgf17 as a key target to restore oligodendrocyte function in the ageing brain.
This is a preview of subscription content
Access options
Subscribe to Journal
Get full journal access for 1 year
£199.00
only £3.90 per issue
Tax calculation will be finalised during checkout.
Buy article
Get time limited or full article access on ReadCube.
$32.00
All prices are NET prices.
Data availability
All data are available in the main text or the Supplementary Information. Raw and processed sequencing data were deposited to NCBI’s Sequence Read Archive and Gene Expression Omnibus databases using accession code GSE198008.
Code availability
All analyses were carried out using freely available software packages. Custom code used to analyse the RNA-seq data and datasets generated and/or processed in the current study is available from the corresponding authors on request.
References
-
Pluvinage, J. V. & Wyss-Coray, T. Systemic factors as mediators of brain homeostasis, ageing and neurodegeneration. Nat. Rev. Neurosci. 21, 93–102 (2020).
-
Castellano, J. M. et al. Human umbilical cord plasma proteins revitalize hippocampal function in aged mice. Nature 544, 488–492 (2017).
-
Villeda, S. A. et al. Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice. Nat. Med. 20, 659–663 (2014).
-
Lehtinen, M. K. et al. The cerebrospinal fluid provides a proliferative niche for neural progenitor cells. Neuron 69, 893–905 (2011).
-
Silva-Vargas, V., Maldonado-Soto, A. R., Mizrak, D., Codega, P. & Doetsch, F. Age-dependent niche signals from the choroid plexus regulate adult neural stem cells. Cell Stem Cell 19, 643–652 (2016).
-
Fame, R. M. & Lehtinen, M. K. Emergence and developmental roles of the cerebrospinal fluid system. Dev. Cell 52, 261–275 (2020).
-
Chen, C. P., Chen, R. L. & Preston, J. E. The influence of ageing in the cerebrospinal fluid concentrations of proteins that are derived from the choroid plexus, brain, and plasma. Exp. Gerontol. 47, 323–328 (2012).
-
Baird, G. S. et al. Age-dependent changes in the cerebrospinal fluid proteome by slow off-rate modified aptamer array. Am. J. Pathol. 180, 446–456 (2012).
-
Li, G. et al. Cerebrospinal fluid concentration of brain-derived neurotrophic factor and cognitive function in non-demented subjects. PLoS ONE 4, e5424 (2009).
-
Pan, S., Mayoral, S. R., Choi, H. S., Chan, J. R. & Kheirbek, M. A. Preservation of a remote fear memory requires new myelin formation. Nat. Neurosci. 23, 487–499 (2020).
-
Vetere, G. et al. Chemogenetic interrogation of a brain-wide fear memory network in mice. Neuron 94, 363–374 (2017).
-
Fogel, S. M. et al. fMRI and sleep correlates of the age-related impairment in motor memory consolidation. Hum. Brain Mapp. 35, 3625–3645 (2014).
-
Gibson, E. M. et al. Neuronal activity promotes oligodendrogenesis and adaptive myelination in the mammalian brain. Science 344, 1252304 (2014).
-
Dugas, J. C. & Emery, B. Purification of oligodendrocyte precursor cells from rat cortices by immunopanning. Cold Spring Harb. Protoc. 2013, 745–758 (2013).
-
Sun, L. O. et al. Spatiotemporal control of CNS myelination by oligodendrocyte programmed cell death through the TFEB–PUMA axis. Cell 175, 1811–1826 (2018).
-
Zuchero, J. B. et al. CNS myelin wrapping is driven by actin disassembly. Dev. Cell 34, 152–167 (2015).
-
Schwarz, N. et al. Human cerebrospinal fluid promotes long-term neuronal viability and network function in human neocortical organotypic brain slice cultures. Sci. Rep. 7, 12249 (2017).
-
Wentling, M. et al. A metabolic perspective on CSF-mediated neurodegeneration in multiple sclerosis. Brain 142, 2756–2774 (2019).
-
Mathur, D. et al. Bioenergetic failure in rat oligodendrocyte progenitor cells treated with cerebrospinal fluid derived from multiple sclerosis patients. Front. Cell. Neurosci. 11, 209 (2017).
-
Braun, T. & Gautel, M. Transcriptional mechanisms regulating skeletal muscle differentiation, growth and homeostasis. Nat. Rev. Mol. Cell Biol. 12, 349–361 (2011).
-
Guo, Y. et al. Hierarchical and stage-specific regulation of murine cardiomyocyte maturation by serum response factor. Nat. Commun. 9, 3837 (2018).
-
Knoll, B. & Nordheim, A. Functional versatility of transcription factors in the nervous system: the SRF paradigm. Trends Neurosci. 32, 432–442 (2009).
-
Miralles, F., Posern, G., Zaromytidou, A. I. & Treisman, R. Actin dynamics control SRF activity by regulation of its coactivator MAL. Cell 113, 329–342 (2003).
-
Knoll, B. et al. Serum response factor controls neuronal circuit assembly in the hippocampus. Nat. Neurosci. 9, 195–204 (2006).
-
Lahoute, C. et al. Premature aging in skeletal muscle lacking serum response factor. PLoS ONE 3, e3910 (2008).
-
Mergoud Dit Lamarche, A. et al. UNC-120/SRF independently controls muscle aging and lifespan in Caenorhabditis elegans. Aging Cell 17, e12713 (2018).
-
Ximerakis, M. et al. Single-cell transcriptomic profiling of the aging mouse brain. Nat. Neurosci. 22, 1696–1708 (2019).
-
Falcao, A. M. et al. Disease-specific oligodendrocyte lineage cells arise in multiple sclerosis. Nat. Med. 24, 1837–1844 (2018).
-
Iacono, G., Altafini, C. & Torre, V. Early phase of plasticity-related gene regulation and SRF dependent transcription in the hippocampus. PLoS ONE 8, e68078 (2013).
-
Kuzniewska, B. et al. Brain-derived neurotrophic factor induces matrix metalloproteinase 9 expression in neurons via the serum response factor/c-Fos pathway. Mol. Cell. Biol. 33, 2149–2162 (2013).
-
Sasayama, D. et al. Genome-wide quantitative trait loci mapping of the human cerebrospinal fluid proteome. Hum. Mol. Genet. 26, 44–51 (2017).
-
Sathyan, S. et al. Plasma proteomic profile of age, health span, and all-cause mortality in older adults. Aging Cell 19, e13250 (2020).
-
Esnault, C. et al. Rho–actin signaling to the MRTF coactivators dominates the immediate transcriptional response to serum in fibroblasts. Genes Dev. 28, 943–958 (2014).
-
Fortin, D., Rom, E., Sun, H., Yayon, A. & Bansal, R. Distinct fibroblast growth factor (FGF)/FGF receptor signaling pairs initiate diverse cellular responses in the oligodendrocyte lineage. J. Neurosci. 25, 7470–7479 (2005).
-
Ramanan, N. et al. SRF mediates activity-induced gene expression and synaptic plasticity but not neuronal viability. Nat. Neurosci. 8, 759–767 (2005).
-
Etkin, A. et al. A role in learning for SRF: deletion in the adult forebrain disrupts LTD and the formation of an immediate memory of a novel context. Neuron 50, 127–143 (2006).
-
Pan, S., Mayoral, S. R., Choi, H. S., Chan, J. R. & Kheirbek, M. A. Preservation of a remote fear memory requires new myelin formation. Nat. Neurosci. 23, 487–499 (2020).
-
Xiao, L. et al. Rapid production of new oligodendrocytes is required in the earliest stages of motor-skill learning. Nat. Neurosci. 19, 1210–1217 (2016).
-
Steadman, P. E. et al. Disruption of oligodendrogenesis impairs memory consolidation in adult mice. Neuron 105, 150–164 (2020).
-
Wang, F. et al. Myelin degeneration and diminished myelin renewal contribute to age-related deficits in memory. Nat. Neurosci. 23, 481–486 (2020).
-
Chen, J. F. et al. Enhancing myelin renewal reverses cognitive dysfunction in a murine model of Alzheimer’s disease. Neuron 109, 2292–2307 (2021).
-
Segel, M. et al. Niche stiffness underlies the ageing of central nervous system progenitor cells. Nature 573, 130–134 (2019).
-
Neumann, B. et al. Metformin restores CNS remyelination capacity by rejuvenating aged stem cells. Cell Stem Cell 25, 473–485 (2019).
-
Bonetto, G., Belin, D. & Karadottir, R. T. Myelin: a gatekeeper of activity-dependent circuit plasticity? Science 374, eaba6905 (2021).
-
Xu, J., Liu, Z. & Ornitz, D. M. Temporal and spatial gradients of Fgf8 and Fgf17 regulate proliferation and differentiation of midline cerebellar structures. Development 127, 1833–1843 (2000).
-
Furusho, M., Ishii, A., Hebert, J. M. & Bansal, R. Developmental stage-specific role of Frs adapters as mediators of FGF receptor signaling in the oligodendrocyte lineage cells. Glia 68, 617–630 (2020).
-
Oh, L. Y. et al. Fibroblast growth factor receptor 3 signaling regulates the onset of oligodendrocyte terminal differentiation. J. Neurosci. 23, 883–894 (2003).
-
Kang, W., Nguyen, K. C. Q. & Hebert, J. M. Transient redirection of SVZ stem cells to oligodendrogenesis by FGFR3 activation promotes remyelination. Stem Cell Rep. 12, 1223–1231 (2019).
-
Jen, Y. H., Musacchio, M. & Lander, A. D. Glypican-1 controls brain size through regulation of fibroblast growth factor signaling in early neurogenesis. Neural Dev. 4, 33 (2009).
-
Scearce-Levie, K. et al. Abnormal social behaviors in mice lacking Fgf17. Genes Brain Behav. 7, 344–354 (2008).
-
De Miguel, Z. et al. Exercise plasma boosts memory and dampens brain inflammation via clusterin. Nature 600, 494–499 (2021).
-
Liu, L. & Duff, K. A technique for serial collection of cerebrospinal fluid from the cisterna magna in mouse. J. Vis. Exp. https://doi.org/10.3791/960 (2008).
-
Smith, A., Wu, A. H., Lynch, K. L., Ko, N. & Grenache, D. G. Multi-wavelength spectrophotometric analysis for detection of xanthochromia in cerebrospinal fluid and accuracy for the diagnosis of subarachnoid hemorrhage. Clin. Chim. Acta 424, 231–236 (2013).
-
Olsson, M., Arlig, J., Hedner, J., Blennow, K. & Zetterberg, H. Sleep deprivation and cerebrospinal fluid biomarkers for Alzheimer’s disease. Sleep https://doi.org/10.1093/sleep/zsy025 (2018).
-
Olsson, M., Arlig, J., Hedner, J., Blennow, K. & Zetterberg, H. Sleep deprivation and plasma biomarkers for Alzheimer’s disease. Sleep Med. 57, 92–93 (2019).
-
Lynch, H. J., Rivest, R. W. & Wurtman, R. J. Artificial induction of melatonin rhythms by programmed microinfusion. Neuroendocrinology 31, 106–111 (1980).
-
Pluvinage, J. V. et al. CD22 blockade restores homeostatic microglial phagocytosis in ageing brains. Nature 568, 187–192 (2019).
-
Lukinavicius, G. et al. Fluorogenic probes for live-cell imaging of the cytoskeleton. Nat. Methods 11, 731–733 (2014).
-
Friedman, P. L. & Ellisman, M. H. Enhanced visualization of peripheral nerve and sensory receptors in the scanning electron microscope using cryofracture and osmium–thiocarbohydrazide–osmium impregnation. J. Neurocytol. 10, 111–131 (1981).
-
Willingham, M. C. & Rutherford, A. V. The use of osmium–thiocarbohydrazide–osmium (OTO) and ferrocyanide-reduced osmium methods to enhance membrane contrast and preservation in cultured cells. J. Histochem. Cytochem. 32, 455–460 (1984).
-
Ewald, A. J. et al. Mammary collective cell migration involves transient loss of epithelial features and individual cell migration within the epithelium. J. Cell Sci. 125, 2638–2654 (2012).
-
McDonald, K. L. & Webb, R. I. Freeze substitution in 3 hours or less. J. Microsc. 243, 227–233 (2011).
-
Emery, B. & Dugas, J. C. Purification of oligodendrocyte lineage cells from mouse cortices by immunopanning. Cold Spring Harb. Protoc. 2013, 854–868 (2013).
-
Muhar, M. et al. SLAM-seq defines direct gene-regulatory functions of the BRD4–MYC axis. Science 360, 800–805 (2018).
-
Stockel, D. et al. Multi-omics enrichment analysis using the GeneTrail2 web service. Bioinformatics 32, 1502–1508 (2016).
-
Hahn, O. et al. CoolMPS for robust sequencing of single-nuclear RNAs captured by droplet-based method. Nucleic Acids Res. 49, e11 (2021).
-
Newman, A. M. et al. Determining cell type abundance and expression from bulk tissues with digital cytometry. Nat. Biotechnol. 37, 773–782 (2019).
-
Steen, C. B., Liu, C. L., Alizadeh, A. A. & Newman, A. M. Profiling cell type abundance and expression in bulk tissues with CIBERSORTx. Methods Mol. Biol. 2117, 135–157 (2020).
-
Wolf, F. A., Angerer, P. & Theis, F. J. SCANPY: large-scale single-cell gene expression data analysis. Genome Biol. 19, 15 (2018).
-
Schaum, N. et al. Ageing hallmarks exhibit organ-specific temporal signatures. Nature 583, 596–602 (2020).
-
Spitzer, S. O. et al. Oligodendrocyte progenitor cells become regionally diverse and heterogeneous with age. Neuron 101, 459–471 (2019).
-
Mathys, H. et al. Single-cell transcriptomic analysis of Alzheimer’s disease. Nature 570, 332–337 (2019).
-
Zhou, Y. et al. Human and mouse single-nucleus transcriptomics reveal TREM2-dependent and TREM2-independent cellular responses in Alzheimer’s disease. Nat. Med. 26, 131–142 (2020).
-
The Tabula Muris Consortium. A single-cell transcriptomic atlas characterizes ageing tissues in the mouse. Nature 583, 590–595 (2020).
-
Matys, V. et al. TRANSFAC and its module TRANSCompel: transcriptional gene regulation in eukaryotes. Nucleic Acids Res. 34, D108–D110 (2006).
-
Gerstner, N. et al. GeneTrail 3: advanced high-throughput enrichment analysis. Nucleic Acids Res. 48, W515–W520 (2020).
Acknowledgements
We thank the members of the Wyss-Coray and Zuchero laboratories for feedback and support. Specifically, we thank H. Kantarci for advice on TEM tissue processing, imaging and analysis, H. Zhang and K. Dickey for laboratory management, and B. Carter for flow cytometry technical expertise. We thank V. Galata for graphical abstract design. We thank E. Mignot and J. Dalmau for providing human CSF samples. We also thank D. Jorgens and the staff at the University of California–Berkeley Electron Microscope Laboratory for EM sample preparation and data collection. This work was funded by the Department of Veterans Affairs (T.W.-C.), the National Institute on Aging (RF1-AG064897-02 to T.W.-C., T32AG000266 to M.S.H.), the NOMIS Foundation (T.W.-C.), the Nan Fung Life Sciences Aging Research Fund (T.W.-C.), the Glenn Foundation for Aging Research (T.W.-C.), the Big Idea Brain Rejuvenation Project and Interdisciplinary Scholar fellowship from the Wu Tsai Neurosciences Institute (T.W.-C. and T.I.), the Zuckerman STEM leadership fellowship and Tel Aviv University President Award for women postdoctoral scholars (T.I.), the National MS Society Harry Weaver Neuroscience Scholar Award (J.B.Z.), the McKnight Scholar Award (J.B.Z.), the Myra Reinhard Family Foundation and the National Institutes of Health (R01-NS119823 to J.B.Z.). H.Z. is a Wallenberg Scholar supported by grants from the Swedish Research Council (2018-02532), the European Research Council (681712), Swedish State Support for Clinical Research (ALFGBG-720931), the Alzheimer Drug Discovery Foundation (ADDF), USA (201809-2016862) and the UK Dementia Research Institute at UCL.
Ethics declarations
Competing interests
T.W.-C. and T.I. are co-inventors on a patent application related to the work published in this paper (STDU2-39617.101, S21-153-Methods and compositions for improved memory in the aging). H.Z. has served at scientific advisory boards and/or as a consultant for Abbvie, Alector, Annexon, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Novo Nordisk, Passage Bio, Pinteon Therapeutics, Red Abbey Labs, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics and Wave, has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen and Roche, and is a cofounder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside the scope of the submitted work).
Peer review
Peer review information
Nature thanks Klaus-Armin Nave and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 Bulk RNAseq, infusion site details and overall overview of proliferating cells.
a, Relative proportions of cell types as predicted by deconvolution analysis of bulk RNAseq of aged mice infused with aCSF or YM-CSF (aCSF n = 8, YM-CSF n = 7). b, Predicted number of DEGs per cell type by deconvolution analysis of bulk RNAseq of aged mice infused with aCSF or YM-CSF (aCSF n = 8, YM-CSF n = 7). c, Effect size of the subset of oligodendrocyte genes in Fig. 1d 16 h following acute injection of YM-CSF or aged mouse CSF (AM-CSF) calculated over aCSF as control (n = 4; Wilcoxon rank sum test). d, Location of infusion site. Image source: Allen Institute, Mouse brain atlas (coronal). e, Location of analysis site. Image source: Allen Institute, Mouse brain atlas (coronal). f, Hippocampal slice of 10-month-old mice given an EdU pulse prior to surgery showing low baseline proliferation, and three pulses of BrdU at day 5 and 6 of infusion showing an overall increase in proliferating cells following YM-CSF infusion (n = 4 per group; repeated measures two-way ANOVA followed by Sidak’s post-hoc test; Means ± SEM). g, Representative images of EdU (red) and BrdU (green) cells in mice with no surgery or infused with aCSF or YM-CSF. Scale bar, 500 μm. h, RNAscope of Pdgfrα+EdU+ cells in hippocampus of 2-month-old (young) and 19-month-old (aged) mice (n = 3; two-sided t-test; mean ± s.e.m.). i, Representative images of analysis in panel h. Arrows pointing to Pdgfrα+EdU+ cells. Scale bar, 100 μm.
Extended Data Fig. 2 Cortical Pdgfrα+EdU+ cells and identity of Pdgfrα− EDU+ cells.
a, Hippocampal density of Pdgfrα+ EdU+ cells per mm2 (aCSF n = 7, YM-CSF n = 8; two-sided t-test; mean ± s.e.m.). b, Hippocampal density of Pdgfrα+ cells per mm2 (aCSF n = 7, YM-CSF n = 8; two-sided t-test; mean ± s.e.m.). c, Location of region of interest in the cortex. Scale bar, 100 μm. d, Percentage of Pdgfrα+ EdU+ / Pdgfrα+ cells showing very low proliferation rates of OPCs in the cortex (n = 6; two-sided t-test; mean ± s.e.m.). e, Cortical density of Pdgfrα+ EdU+ cells per mm2 (n = 6; two-sided t-test; mean ± s.e.m.). f, Cortical density of Pdgfrα+ cells per mm2 (n = 6; two-sided t-test; mean ± s.e.m.). g, Percentage of Pdgfrα+ EdU+ / EdU+ in the hippocampus of aged mice infused with YM-CSF (n = 3). h, Example of IBA+ EdU+ cells in the hippocampus (n = 3). Scale bar, 50 μm. Insert, 10 μm. i, Example of GFAP+ EdU+ cells in the hippocampus (n = 3). Scale bar, 50 μm. Insert, 10 μm.
Extended Data Fig. 3 Young CSF increases number of myelinated axons in the molecular layer.
a, Representative overview of 1mm diameter biopsy punch in the hippocampus. b, Representative overview of molecular layer (MoL, between dashed lines) before and after TEM imaging of three 10×10 montage squares (n=7). c, Representative montage of MoL of aged mouse infused with aCSF and YM-CSF (n = 7). Scale bar, 10 μm. d, Representative higher resolution image of aged mouse infused with aCSF and YM-CSF (n = 7). Scale bar, 1 μm. e, g-ratio analysis of myelinated axons in molecular layer. (n = 3 mice per group, aCSF n = 321 axons, YM-CSF n = 291 axons).
Extended Data Fig. 4 Young CSF boosts OPC differentiation in vitro and validation of OPC culture purity.
a, Related to images in Fig 1o. Overview of MBP stain of OLs at day 4 of differentiation supplemented with 10% aCSF or YH-CSF (aCSF n = 3 coverslips, YH-CSF n = 2 coverslips). b, Quantification of MBP intensity of day 4 differentiated OLs. Scale bar, 200 μm. (aCSF n = 3 coverslips, YH-CSF n = 2 coverslips; two-sided t-test; mean ± s.e.m). c, Primary rat OPC cultures were supplemented with 10% aCSF or YH-CSF for 6 h and stained for NG2 (green), Olig2 (grey) and Acta2 (red). (n = 3 coverslips; Scale bar, 100 μm). d, Higher magnification of primary rat OPC cultures were supplemented with 10% aCSF or YH-CSF for 6 h and stained for NG2 (green), Olig2 (grey) and Acta2 (red). (n = 3 coverslips; Scale bar, 20 μm).
Extended Data Fig. 5 SLAMseq QC and principal component analysis.
a, Overall conversion rates in all SLAMseq samples, showing an enrichment for T>C mutation rate (orange bar) which increases with longer incubation time (6 h). b–c, Distribution of T>C mutations across b, read position and c, 3’UTR position indicating an equal distribution of s4U incorporation along the positive strand. d–e, UMAP of aCSF and YH-CSF samples in both time points by all genes detected in the d, total and e, nascent mRNA counts. (young CSF 1 h n = 4, all the rest n = 5). f, Gene set enrichment analysis (GSEA) of 6hr genes sorted by log2FC showing an enrichment for SRF target genes by TRANSFAC75. g, Overall log2FC enrichment indicating upregulation of SRF target genes (TRANSFAC and curated list) and actin cytoskeleton genes in YH-CSF treated OPCs over aCSF. (SRF TRANSFAC (423 genes), validated SRF targets from literature (74 genes) and actin genes (212 genes); Wilcoxon rank sum test; box show the median and the 25–75th percentiles, and the whiskers indicate values up to 1.5-times the interquartile range).
Extended Data Fig. 6 YH-CSF induces actin cytoskeleton alterations in vitro.
a–b, Actin filament content measured by live imaging using SiR-actin (red) throughout 4hr of aCSF and YH-CSF exposure. Average SiR-actin a, intensity and b, area in rat OPC cultures exposed to aCSF or YH-CSF (n = 6 wells per condition; Means ± SEM). c, Representative images of experiment quantified in panel a and b. Scale bar 200 μm. d, OPC coverslips were treated with YH-CSF for 6 h and stained for phalloidin. Histogram of the percentage of OPC with the indicated number of growth cones per cell. YH-CSF treated cells show a shift towards more growth cones per cell (n = 3 coverslips per condition, total of 200 cells analyzed per condition; two-way ANOVA followed by Sidak’s post-hoc test; Means ± SEM). Scale bar 20 μm. e, mouse OPC primary cultures from SRF-fl/fl pups infected with CRE-GFP and △CRE-GFP AAVs to induce recombination. Representative images of infected cells (green) 48 h after infection. Scale bar, 100 μm. f, Normalized SRF mRNA levels as measured by RT-PCR (n = 3 coverslips per condition; mean ± s.e.m.). g, Representative image of data presented in figure 2h. Scale bar, 20 μm. h, Quantification of GFP+ cells per image in SRF-WT and SRF-KO cells treated with 10% aCSF or YH-CSF. (n = 3; mean ± s.e.m.). i, Quantification of number of DAPI cells per image in SRF-WT and SRF-KO cells treated with 10% aCSF or YH-CSF. (n = 3; mean ± s.e.m.). Data in panels a-i were replicated in two independent experiments.
Extended Data Fig. 7 Bulk RNAseq of hippocampal OPC and OL nuclei from young and aged mice.
a, Gating strategy for sorting of hippocampal OPC and OL nuclei. b, Heatmap of expression OPC and OL specific genes across young and aged OPC and OL samples (aged OL n = 3, rest n = 4). c, Volcano plot showing OL genes up and downregulated with age (n = 4; p. adjusted value by Wald test in DESeq2). d, Pathways enriched (red) or depleted (blue) in hippocampal OLs with age (unweighted Kolmogorov-Smirnow test).
Extended Data Fig. 8 Bulk RNAseq of hippocampal OPC and OL nuclei from aged mice following acute injection and Srf levels in neurons.
a, Box plot of effect size of Srf targets (TRANSFAC database) in hippocampal OLs from aged vs. young, YM-CSF vs. aCSF at 1 h and 6 h timepoints (n = 4; genes pre-filtered by p < 0.05 cutoff; Wilcoxon rank sum test, box show the median and the 25–75th percentiles, and
