Perineuronal nets (PNNs) are chondroitin sulphate proteoglycan-containing structures on the neuronal surface that have been implicated in the control of neuroplasticity and memory. Age-related reduction of chondroitin 6-sulphates (C6S) leads to PNNs becoming more inhibitory. Here, we investigated whether manipulation of the chondroitin sulphate (CS) composition of the PNNs could restore neuroplasticity and alleviate memory deficits in aged mice. We first confirmed that aged mice (20-months) showed memory and plasticity deficits. They were able to retain or regain their cognitive ability when CSs were digested or PNNs were attenuated. We then explored the role of C6S in memory and neuroplasticity. Transgenic deletion of chondroitin 6-sulfotransferase (chst3) led to a reduction of permissive C6S, simulating aged brains. These animals showed very early memory loss at 11 weeks old. Importantly, restoring C6S levels in aged animals rescued the memory deficits and restored cortical long-term potentiation, suggesting a strategy to improve age-related memory impairment.

Centre for Reconstructive Neuroscience Institute of Experimental Medicine CAS Prague Czech Republic

Department NEUROFARBA University of Florence Florence Italy

Department of Biochemistry Kobe Pharmaceutical University Kobe Japan

Division of Neurosurgery National University Hospital Singapore Singapore

Institute of Neuroscience CNR Pisa Italy

John van Geest Centre for Brain Repair University of Cambridge Cambridge UK

Laboratory for Regeneration of Sensorimotor Systems Netherlands Institute for Neuroscience Royal Netherlands Academy of Arts and Sciences Amsterdam The Netherlands

Molecular Medicine Research Group Robarts Research Institute Schulich School of Medicine and Dentistry Western University London Canada

School of Biomedical Sciences Faculty of Biological Sciences University of Leeds Leeds UK

See more in PubMed

van’t Spijker HM, Kwok JCF. A Sweet talk: the molecular systems of perineuronal nets in controlling neuronal communication. Front Integr Neurosci. 2017;11:1–10. PubMed PMC

Sorg BA, Berretta S, Blacktop JM, Fawcett JW, Kitagawa H, Kwok JC, et al. Casting a wide net: role of perineuronal nets in neural plasticity. J Neurosci. 2016;36:11459–68. PubMed PMC

Oohashi T, Edamatsu M, Bekku Y, Carulli D. The hyaluronan and proteoglycan link proteins: organizers of the brain extracellular matrix and key molecules for neuronal function and plasticity. Exp Neurol. 2015;274:134–44. PubMed

Spatazza J, Lee HH, Di Nardo AA, Tibaldi L, Joliot A, Hensch TK, et al. Choroid-plexus-derived Otx2 homeoprotein constrains adult cortical plasticity. Cell Rep. 2013;3:1815–23. PubMed PMC

Fawcett JW, Oohashi T, Pizzorusso T. The roles of perineuronal nets and the perinodal extracellular matrix in neuronal function. Nat Rev Neurosci. 2019;20:451–65. PubMed

Pizzorusso T, Medini P, Berardi N, Chierzi S, Fawcett JW, Maffei L. Reactivation of ocular dominance plasticity in the adult visual cortex. Science. 2002;298:1248–51. PubMed

Kwok JCF, Carulli D, Fawcett JW. In vitro modeling of perineuronal nets: hyaluronan synthase and link protein are necessary for their formation and integrity. J Neurochem. 2010;114:1447–59. PubMed

Giamanco KA, Matthews RT. Deconstructing the perineuronal net: cellular contributions and molecular composition of the neuronal extracellular matrix. Neuroscience. 2012;218:367–84. PubMed PMC

Vo T, Carulli D, Ehlert EME, Kwok JCF, Dick G, Mecollari V, et al. The chemorepulsive axon guidance protein semaphorin3A is a constituent of perineuronal nets in the adult rodent brain. Mol Cell Neurosci. 2013;56:186–200. PubMed

Suttkus A, Rohn S, Weigel S, Glockner P, Arendt T, Morawski M. Aggrecan, link protein and tenascin-R are essential components of the perineuronal net to protect neurons against iron-induced oxidative stress. Cell Death Dis. 2014;5:e1119. PubMed PMC

Dick G, Tan CL, Alves JN, Ehlert EM, Miller GM, Hsieh-Wilson LC, et al. Semaphorin 3A binds to the perineuronal nets via chondroitin sulfate type E motifs in rodent brains. J Biol Chem. 2013;288:27384–95. PubMed PMC

Lin R, Rosahl TW, Whiting PJ, Fawcett JW, Kwok JC. 6-sulphated chondroitins have a positive influence on axonal regeneration. PLoS ONE. 2011;6:e21499. PubMed PMC

Miyata S, Komatsu Y, Yoshimura Y, Taya C, Kitagawa H. Persistent cortical plasticity by upregulation of chondroitin 6-sulfation. Nat Neurosci. 2012;15:414–22. PubMed

Beurdeley M, Spatazza J, Lee HH, Sugiyama S, Bernard C, Di Nardo AA, et al. Otx2 binding to perineuronal nets persistently regulates plasticity in the mature visual cortex. J Neurosci. 2012;32:9429–37. PubMed PMC

Kitagawa H, Tsutsumi K, Tone Y, Sugahara K. Developmental regulation of the sulfation profile of chondroitin sulfate chains in the chicken embryo brain. J Biol Chem. 1997;272:31377–81. PubMed

Kwok JC, Warren P, Fawcett JW. Chondroitin sulfate: a key molecule in the brain matrix. Int J Biochem Cell Biol. 2012;44:582–6. PubMed

Wang H, Katagiri Y, McCann TE, Unsworth E, Goldsmith P, Yu ZX, et al. Chondroitin-4-sulfation negatively regulates axonal guidance and growth. J Cell Sci. 2008;121:3083–91. PubMed PMC

Deepa SS, Carulli D, Galtrey C, Rhodes K, Fukuda J, Mikami T, et al. Composition of perineuronal net extracellular matrix in rat brain: a different disaccharide composition for the net-associated proteoglycans. J Biol Chem. 2006;281:17789–17800. PubMed

Foscarin S, Raha-Chowdhury R, Fawcett JW, Kwok JCF. Brain ageing changes proteoglycan sulfation, rendering perineuronal nets more inhibitory. Aging. 2017;9:1607–22. PubMed PMC

Gogolla N, Caroni P, Luthi A, Herry C. Perineuronal nets protect fear memories from erasure. Science. 2009;325:1258–61. PubMed

Slaker M, Churchill L, Todd RP, Blacktop JM, Zuloaga DG, Raber J, et al. Removal of perineuronal nets in the medial prefrontal cortex impairs the acquisition and reconsolidation of a cocaine-induced conditioned place preference memory. J Neurosci. 2015;35:4190–202. PubMed PMC

Romberg C, Yang S, Melani R, Andrews MR, Horner AE, Spillantini MG, et al. Depletion of perineuronal nets enhances recognition memory and long-term depression in the perirhinal cortex. J Neurosci. 2013;33:7057–65. PubMed PMC

Carulli D, Broersen R, de Winter F, Muir EM, Meskovic M, de Waal M, et al. Cerebellar plasticity and associative memories are controlled by perineuronal nets. Proc Natl Acad Sci USA. 2020;117:6855–65. PubMed PMC

Caroni P. Inhibitory microcircuit modules in hippocampal learning. Curr Opin Neurobiol. 2015;35:66–73. PubMed

Letzkus JJ, Wolff SB, Luthi A. Disinhibition, a circuit mechanism for associative learning and memory. Neuron. 2015;88:264–76. PubMed

Donato F, Rompani SB, Caroni P. Parvalbumin-expressing basket-cell network plasticity induced by experience regulates adult learning. Nature. 2013;504:272–6. PubMed

Ferrer-Ferrer M, Dityatev A. Shaping synapses by the neural extracellular matrix. Front Neuroanat. 2018;12:40. PubMed PMC

Rowlands D, Lensjø KK, Dinh T, Yang S, Andrews MR, Hafting T, et al. Aggrecan directs extracellular matrix-mediated neuronal plasticity. J Neurosci. 2018;38:10102–13. PubMed PMC

Vegh MJ, Heldring CM, Kamphuis W, Hijazi S, Timmerman AJ, Li KW, et al. Reducing hippocampal extracellular matrix reverses early memory deficits in a mouse model of Alzheimer’s disease. Acta Neuropathol Commun. 2014;2:76. PubMed PMC

Yang S, Hilton S, Alves JN, Saksida LM, Bussey T, Matthews RT, et al. Antibody recognizing 4-sulfated chondroitin sulfate proteoglycans restores memory in tauopathy-induced neurodegeneration. Neurobiol Aging. 2017;59:197–209. PubMed

Yang S, Cacquevel M, Saksida LM, Bussey TJ, Schneider BL, Aebischer P, et al. Perineuronal net digestion with chondroitinase restores memory in mice with tau pathology. Exp Neurol. 2015;265:48–58. PubMed PMC

Carulli D, Kwok JC, Pizzorusso T. Perineuronal nets and CNS plasticity and repair. Neural Plast. 2016;2016:4327082. PubMed PMC

Morawski M, Filippov M, Tzinia A, Tsilibary E, Vargova L. ECM in brain aging and dementia. Prog Brain Res. 2014;214:207–27. PubMed

Barreto G, Huang T-T, Giffard RG. Age-related defects in sensorimotor activity, spatial learning, and memory in C57BL/6 mice. J Neurosurg Anesthesiol. 2010;22:214–9. PubMed PMC

de Brouwer G, Wolmarans W. Back to basics: a methodological perspective on marble-burying behavior as a screening test for psychiatric illness. Behav Process. 2018;157:590–600. PubMed

Winters BD, Saksida LM, Bussey TJ. Object recognition memory: neurobiological mechanisms of encoding, consolidation and retrieval. Neurosci Biobehav Rev. 2008;32:1055–70. PubMed

Frechou M, Margaill I, Marchand-Leroux C, Beray-Berthat V. Behavioral tests that reveal long-term deficits after permanent focal cerebral ischemia in mouse. Behav Brain Res. 2019;360:69–80. PubMed

Carulli D, Pizzorusso T, Kwok JC, Putignano E, Poli A, Forostyak S, et al. Animals lacking link protein have attenuated perineuronal nets and persistent plasticity. Brain. 2010;133:2331–47. PubMed

Lin R, Kwok JC, Crespo D, Fawcett JW. Chondroitinase ABC has a long-lasting effect on chondroitin sulphate glycosaminoglycan content in the injured rat brain. J Neurochem. 2008;104:400–8. PubMed

Spliid CB, Toledo AG, Salanti A, Esko JD, Clausen TM. Beware, commercial chondroitinases vary in activity and substrate specificity. Glycobiology. 2020;31:103–15. PubMed

Donato F, Chowdhury A, Lahr M, Caroni P. Early- and late-born parvalbumin basket cell subpopulations exhibiting distinct regulation and roles in learning. Neuron. 2015;85:770–86. PubMed

Pantazopoulos H, Markota M, Jaquet F, Ghosh D, Wallin A, Santos A, et al. Aggrecan and chondroitin-6-sulfate abnormalities in schizophrenia and bipolar disorder: a postmortem study on the amygdala. Transl Psychiatry. 2015;5:e496. PubMed PMC

Lensjo KK, Lepperod ME, Dick G, Hafting T, Fyhn M. Removal of perineuronal nets unlocks juvenile plasticity through network mechanisms of decreased inhibition and increased gamma activity. J Neurosci. 2017;37:1269–83. PubMed PMC

Liguz-Lecznar M, Lehner M, Kaliszewska A, Zakrzewska R, Sobolewska A, Kossut M. Altered glutamate/GABA equilibrium in aged mice cortex influences cortical plasticity. Brain Struct Funct. 2015;220:1681–93. PubMed

Rossiter HE, Davis EM, Clark EV, Boudrias MH, Ward NS. Beta oscillations reflect changes in motor cortex inhibition in healthy ageing. Neuroimage. 2014;91:360–5. PubMed PMC

Miyata S, Kitagawa H. Chondroitin 6-sulfation regulates perineuronal net formation by controlling the stability of aggrecan. Neural Plast. 2016;2016:1305801. PubMed PMC

Hensch TK, Quinlan EM. Critical periods in amblyopia. Vis Neurosci. 2018;35:E014. PubMed

Carstens KE, Phillips ML, Pozzo-Miller L, Weinberg RJ, Dudek SM. Perineuronal nets suppress plasticity of excitatory synapses on CA2 pyramidal neurons. J Neurosci. 2016;36:6312–20. PubMed PMC

Suttkus A, Morawski M, Arendt T. Protective properties of neural extracellular matrix. Mol Neurobiol. 2014;53:73–82. PubMed

Miyata S, Kitagawa H. Mechanisms for modulation of neural plasticity and axon regeneration by chondroitin sulphate. J Biochem. 2015;157:13–22. PubMed

Miyata S, Kitagawa H. Formation and remodeling of the brain extracellular matrix in neural plasticity: Roles of chondroitin sulfate and hyaluronan. Biochim Biophys Acta. 2017;1861:2420–34. PubMed

Caroni P, Chowdhury A, Lahr M. Synapse rearrangements upon learning: from divergent-sparse connectivity to dedicated sub-circuits. Trends Neurosci. 2014;37:604–14. PubMed

Sakamoto K, Ozaki T, Ko YC, Tsai CF, Gong Y, Morozumi M, et al. Glycan sulfation patterns define autophagy flux at axon tip via PTPRsigma-cortactin axis. Nat Chem Biol. 2019;15:699–709. PubMed

Djerbal L, Lortat-Jacob H, Kwok J. Chondroitin sulfates and their binding molecules in the central nervous system. Glycoconj J. 2017;34:363–76. PubMed PMC

Steullet P, Cabungcal JH, Cuenod M, Do KQ. Fast oscillatory activity in the anterior cingulate cortex: dopaminergic modulation and effect of perineuronal net loss. Front Cell Neurosci. 2014;8:244. PubMed PMC

Rao-Ruiz P, Yu J, Kushner SA, Josselyn SA. Neuronal competition: microcircuit mechanisms define the sparsity of the engram. Curr Opin Neurobiol. 2019;54:163–70. PubMed PMC

Josselyn SA, Frankland PW. Memory allocation: mechanisms and function. Annu Rev Neurosci. 2018;41:389–413. PubMed PMC

Nix P, Bastiani M. Neuroscience. Heterochronic genes turn back the clock in old neurons. Science. 2013;340:282–3. PubMed

Adalbert R, Coleman MP. Axon pathology in age-related neurodegenerative disorders. Neuropathol Appl Neurobiol. 2012;39:90–108. PubMed

Peleg S, Sananbenesi F, Zovoilis A, Burkhardt S, Bahari-Javan S, Agis-Balboa RC, et al. Altered histone acetylation is associated with age-dependent memory impairment in mice. Science. 2010;328:753–6. PubMed

Moore DL, Pilz GA, Arauzo-Bravo MJ, Barral Y, Jessberger S. A mechanism for the segregation of age in mammalian neural stem cells. Science. 2015;349:1334–8. PubMed

Kwok JC, Foscarin S, Fawcett JW. Perineuronal nets: a special structure in the central nervous system extracellular matrix. Neuromethods. 2015;93:32.

Verhaagen J, Hobo B, Ehlert EME, Eggers R, Korecka JA, Hoyng SA, et al. Small scale production of recombinant adeno-associated viral vectors for gene delivery to the nervous system. Methods Mol Biol. 2018;1715:3–17. PubMed

Ippolito DM, Eroglu C. Quantifying synapses: an immunocytochemistry-based assay to quantify synapse number. J Vis Exp. 2010;45:2270. PubMed PMC

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