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Cited by 111Neuroscience and Neuropharmacology ResearchProteoglycans and glycosaminoglycans researchNeurogenesis and neuroplasticity mechanisms

Elimination of the four extracellular matrix molecules tenascin-C, tenascin-R, brevican and neurocan alters the ratio of excitatory and inhibitory synapses

Open access
Gottschling, Christine, Wegrzyn, David, Denecke, Bernd, Faissner, Andreas·2019·Scientific Reports
DOI 10.1038/s41598-019-50404-9PMC PMC6763627
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Abstract

The synaptic transmission in the mammalian brain is not limited to the interplay between the pre- and the postsynapse of neurons, but involves also astrocytes as well as extracellular matrix (ECM) molecules. Glycoproteins, proteoglycans and hyaluronic acid of the ECM pervade the pericellular environment and condense to special superstructures termed perineuronal nets (PNN) that surround a subpopulation of CNS neurons. The present study focuses on the analysis of PNNs in a quadruple knockout mouse deficient for the ECM molecules tenascin-C (TnC), tenascin-R (TnR), neurocan and brevican. Here, we analysed the proportion of excitatory and inhibitory synapses and performed electrophysiological recordings of the spontaneous neuronal network activity of hippocampal neurons in vitro. While we found an increase in the number of excitatory synaptic molecules in the quadruple knockout cultures, the number of inhibitory synaptic molecules was significantly reduced. This observation was complemented with an enhancement of the neuronal network activity level. The in vivo analysis of PNNs in the hippocampus of the quadruple knockout mouse revealed a reduction of PNN size and complexity in the CA2 region. In addition, a microarray analysis of the postnatal day (P) 21 hippocampus was performed unravelling an altered gene expression in the quadruple knockout hippocampus.

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Written from the paper’s full text.

TL;DR

Eliminating four extracellular matrix molecules (tenascin-C, tenascin-R, brevican, neurocan) in a quadruple knockout mouse shifts hippocampal cultures toward more excitatory and fewer inhibitory synapses, with increased spontaneous network activity. In vivo, CA2 perineuronal nets are smaller and less intense during development but normalize by P35, and P21 hippocampal gene expression is altered.

Key findings

  • Excitatory synaptic puncta increased in quadruple knockout hippocampal cultures: PNN-bearing knockout neurons with knockout astrocytes at 14 DIV showed PSD95 +30.18 ± 5.79% (p = 0.002) and colocalized vGlut1 +38.31 ± 10.19% (p = 0.040); PNN-free knockout neurons with knockout astrocytes showed structural excitatory synapses +52.24 ± 8.51% (p < 0.001).
  • Inhibitory synaptic puncta decreased: PNN-positive knockout neurons with knockout astrocytes at 14 DIV showed gephyrin −21.15 ± 2.75% (p = 0.008) and inhibitory synapses −24.25 ± 3.98% (p = 0.016); PNN-free knockout neurons with knockout astrocytes showed vGAT −30.22 ± 4.01%, gephyrin −13.70 ± 2.08%, and inhibitory synapses −35.11 ± 3.24% (all p ≤ 0.049).
  • MEA recordings showed higher spontaneous network activity in knockout neurons with knockout astrocytes: spikes were 4306.84 ± 217.87 at 14 DIV and 8762.16 ± 454.98 at 21 DIV versus control 2348.39 ± 153.26 and 4367.73 ± 261.28 (p < 0.001); bursts were 101.04 ± 4.78 and 195.45 ± 6.82 versus control 57.6 ± 3.22 and 109.38 ± 5.75 (p < 0.001).
  • In vivo CA2 PNN area was reduced at P15–P30, e.g. P15 knockout 42558.46 ± 3223.24 µm² versus wildtype 64155.52 ± 3273.71 µm² (p < 0.001), and P30 knockout 63620.73 ± 5082.00 µm² versus wildtype 104404.09 ± 7588.34 µm² (p < 0.001), with no significant difference at P35 (p = 0.120). Microarray of P21 hippocampus examined 34473 genes and found 438 significantly altered, including Col1a2 (−1.35-fold, p = 0.0017), Spon2 (−1.33-fold, p = 0.0002), Gpc3 (1.40-fold, p = 0.0089), Gad2 (1.32-fold, p = 0.0062), and Gabrq (1.52-fold, p = 0.0310).

Methods

  • Indirect co-culture of hippocampal neurons and cortical astrocytes from wildtype and quadruple knockout mice in four combinations, analyzed at 14 and 21 DIV by immunocytochemistry for vGlut1/PSD95 (excitatory), vGAT/gephyrin (inhibitory), and aggrecan (PNN); five independent experiments with 20 PNN-positive and 20 PNN-negative neurons per condition, totaling 800 neurons.
  • Spontaneous network activity recorded on 60-electrode MEAs for 10 min at 20 kHz with spike detection threshold 4.5-fold above standard deviation; five independent experiments with 60 electrodes per condition.
  • In vivo PNN analysis used WFA/aggrecan/NF200 immunohistochemistry in hippocampus at P15–P35 with area and corrected total cell fluorescence quantification; Affymetrix Mouse Gene 2.0 ST microarray compared P21 hippocampus of wildtype and quadruple knockout siblings in triplicates, with regulated transcripts defined as >1.5-fold change and ANOVA p < 0.05.

Limitations

  • Stated limitations: Not stated in the paper.
  • Evident from the text: the quadruple knockout cannot distinguish effects of individual ECM molecules, and the in vitro co-culture system may not fully capture in vivo synaptic and network behavior.
  • Evident from the text: the microarray was limited to P21 hippocampus with n = 3, and PNN area/fluorescence was manually bordered and quantified; some reported p-values are close to the 0.05 threshold.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41598-019-50404-9

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 70 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    In vivo analysis of PNNs in the hippocampus of the quadruple knockout mouse revealed a reduction of PNN size and complexity in the CA2 region.

    “The in vivo analysis of PNNs in the hippocampus of the quadruple knockout mouse revealed a reduction of PNN size and complexity in the CA2 region.”
    Quote in the paperNot a substantial claim
  • Findingown data

    In quadruple knockout hippocampal cultures, the number of inhibitory synaptic molecules was significantly reduced.

    “the number of inhibitory synaptic molecules was significantly reduced”
    Quote in the paperSubstantial claim
  • Findingown data

    In PNN-positive Nko/ko/Awt/wt cultures at 14 DIV, vGlut1 and PSD95 puncta were not significantly shifted.

    “No significant shift of excitatory puncta was observable for knockout neurons grown with wildtype astrocyte (Nko/ko/Awt/wt) where vGlut1 and PSD95 puncta shifted by 13.38 ± 6.55% (p = 0.185) and 19.97 ± 6.47% (p = 0.392), respectively.”
    Quote in the paperSubstantial claim
  • Findingown data

    In PNN-free Nko/ko/Ako/ko cultures at 14 DIV, structural excitatory synapses increased by 52.24 ± 8.51% compared with control.

    “An even larger rise of excitatory structural synapses was determined for PNN-free knockout neurons cultivated with knockout astrocytes (Nko/ko/Ako/ko) (Fig. 1f). Here, an increase was measured of 52.24 ± 8.51% (p < 0.001) compared to the control condition (Nwt/wt/Awt/wt).”
    Quote in the paperSubstantial claim
  • Findingown data

    In PNN-free Nko/ko/Ako/ko cultures at 14 DIV, delocalized vGlut1 puncta increased by 33.69 ± 6.82%.

    “The delocalized vGlut1 and PSD95 puncta were also significantly elevated by 33.69 ± 6.82% (p < 0.001) and 37.64 ± 5.05% (p < 0.001).”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim. 4
  • May combine two claims. 33
  • Classified as probably not a substantial claim. 41

  • The quote only partly states this claim.

    Findingown data

    In PNN-positive Nko/ko/Awt/wt cultures at 14 DIV, excitatory synapses increased by 47.29 ± 12.49% compared with control.

    “A significant enhancement of 47.29 ± 12.49% (p = 0.050) could be detected for excitatory synapses.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In PNN-free Nko/ko/Awt/wt cultures at 14 DIV, vGlut1 puncta increased by 26.65 ± 5.65%.

    “Analogous results were obtained for knockout neurons grown in the presence of wildtype astrocytes (Nko/ko/Awt/wt) where the vGlut1 puncta were significantly increased by 26.65 ± 5.65% (p = 0.002), as well as the PSD95 puncta (25.14 ± 4.98%, p = 0.002) and the excitatory synapses (49.73 ± 8.01%, p < 0.001).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Quadruple knockout neurons miss the CSPGs neurocan and brevican but still express aggrecan, the PNN marker used in this study.

    “Different from the ChABC-treated cultures, the quadruple knockout neurons miss the CSPGs neurocan and brevican, but still express aggrecan, the PNN marker used in this study, and possibly other CSPGs such as phosphacan45.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Nko/ko/Awt/wt cultures showed reduced spike frequency in bursts after 14 DIV, but no significant difference after 21 DIV.

    “Interestingly, knockout neurons co-cultured with wildtype astrocytes (Nko/ko/Awt/wt) showed an opposite effect concerning their spike frequency in bursts, namely a reduction with a value of 48.54 ± 1.38 Hz (p < 0.001) after 14 DIV. After 21 DIV no significant difference could be observed (75.15 ± 1.91 Hz (p = 0.347)).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In PNN-positive Nko/ko/Ako/ko cultures at 21 DIV, vGAT puncta and inhibitory synapses were not altered.

    “Under this schedule, PNN-positive knockout neurons grown with knockout astrocytes (Nko/ko/Ako/ko) developed significantly lesser gephyrin puncta, while the vGAT puncta and inhibitory synapses were not altered compared to the control (Nwt/wt/Awt/wt); vGAT: −11.66 ± 4.01% (p = 0.287), gephyrin: −20.15 ± 3.50% (p = 0.004) and colocalized puncta: −13.01 ± 3.96% (p = 0.354).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Overall 34473 genes were examined, of which 438 were significantly altered in the quadruple knockout hippocampus.

    “Overall 34473 genes were examined of which 438 were significantly altered in the quadruple knockout hippocampus.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Nko/ko/Awt/wt cultures showed a decreased percentage of spikes in bursts after 14 DIV, attaining control levels after 21 DIV.

    “There was again a significant decrease of this analysed parameter in cultures of knockout neurons cultured with wildtype astrocytes (Nko/ko/Awt/wt) after 14 DIV with a percentage of 23.96 ± 1.31% (p < 0.001) spikes in burst, which attained control levels after 21 DIV, with a percentage of 50.78 ± 1.93% (p = 1.000).”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    In Nwt/wt/Ako/ko cultures at 14 DIV, no differences in excitatory synapses were measured.

    “In contrast, when wildtype neurons were co-cultivated with knockout astrocytes (Nwt/wt/Ako/ko), no differences with regard to excitatory synapses were measured”
    Quote in the paperSubstantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    Spike frequency in bursts was significantly higher in Nko/ko/Ako/ko cultures after 14 DIV and remained higher after 21 DIV compared with control.

    “Knockout neurons grown in the presence of knockout astrocytes (Nko/ko/Ako/ko) showed a significantly higher spike frequency in bursts of 92.18 ± 4.23 Hz (p < 0.001), which occurred after 14 DIV compared to 66.61 ± 2.44 Hz of the control”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cplx3 and Grin2d were significantly diminished, whereas Dnm3, Sema4c, Gad2, Cntnap4 and Gabrq were significantly enhanced in the quadruple knockout hippocampus.

    “The expression of the neuronal genes (Fig. 7f) Cplx3 (−1.17-fold, p = 0.0037) and Grin2d (−1.08-fold, p = 0.0057) was significantly diminished, whereas Dnm3 (1.11-fold, p = 0.0015), Sema4c (1.16-fold, p = 0.0065), Gad2 (1.32-fold, p = 0.0062), Cntnap4 (1.50-fold, p = 0.0198) and Gabrq (1.52-fold, p = 0.0310) were significantly enhanced.”
    Quote in the paperSubstantial claim

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

    Findingown data

    Other CSPGs such as phosphacan may be expressed similarly to wildtype control because the gene array analysis did not reveal substantial modifications of CSPG genes.

    “These may be expressed similar to the wildtype control because the gene array analysis did not reveal substantial modifications of CSPG genes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In PNN-positive Nko/ko/Awt/wt cultures at 21 DIV, vGAT and structural synapses remained unchanged.

    “Here, a significant reduction of −25.44 ± 3.24% (p < 0.001) of gephyrin puncta was quantified, whereas the vGAT (3.45 ± 5.95%, p = 1.000) and the structural synapses (−8.40 ± 5.35%, p = 0.396) remained unchanged.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Adamts13 was decreased, while Cript, Sod3 and Wnt7a were increased in the quadruple knockout hippocampus.

    “as shown by a decreased linear fold change of Adamts13 (−1.17-fold, p = 0.0058) and increased values for the linear fold change of Cript (1.05-fold, p = 0.0083), Sod3 (1.10-fold, p = 0.0081) and Wnt7a (1.33-fold, p = 0.0002).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In PNN-free Nko/ko/Awt/wt cultures at 21 DIV, vGAT and inhibitory synapses were unchanged.

    “The gephyrin puncta were significantly reduced, by −21.63 ± 2.76% (p < 0.001), when knockout neurons were co-cultivated with wildtype astrocytes (Nko/ko/Awt/wt), but no change could be found for the vGAT and inhibitory synapses in this condition (vGAT: 4.80 ± 4.22% (p = 0.795) and colocalized puncta: 2.38 ± 4.52% (p = 1.000)).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In Nwt/wt/Ako/ko cultures at 14 DIV, gephyrin puncta and inhibitory synapses remained unaffected.

    “The combination of wildtype neurons with knockout astrocytes (Nwt/wt/Ako/ko) resulted in a decrease of vGAT puncta by −17.83 ± 3.64% (p = 0.035), while the gephyrin puncta as well as the inhibitory synapses remained unaffected (4.99 ± 2.88%, p = 0.372; and −10.12 ± 3.64%, p = 0.667).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    The initiation of PNN formation in the murine hippocampus detectable by WFA occurred between postnatal stage P10 and P15.

    “The initiation of PNN formation in the murine hippocampus detectable by WFA occurred between postnatal stage P10 and P15.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Neither TnW nor TnX are elevated in the quadruple knockout mouse.

    “For example, the tenascin family comprises the four genes TnC, TnR, TnW and TnX, but neither TnW nor TnX are elevated in the quadruple knockout mouse48,49.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the quadruple knockout mouse neuronal network in vitro, an increased number of excitatory synapses resulted in enhanced synaptic transmission, recorded via MEA analysis.

    “This is in agreement with our observation that an increased number of excitatory synapses resulted in enhanced synaptic transmission in the neuronal network of the quadruple knockout mouse, which was recorded via MEA analysis in vitro.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    PNNs are highly enriched in the CA2 region of the murine hippocampus.

    “it has recently been reported that PNNs are highly enriched in the CA2 region of the murine hippocampus33.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] Carstens, K. E., Phillips, M. L., Pozzo-Miller, L., Weinberg, R. J. & Dudek, S. M. Perineuronal Nets Suppress Plasticity of Excitatory Synapses on CA2 Pyramidal Neurons. J Neurosci 36, 6312–6320, https://doi.org/10.1523/JNEUROSCI.0245-16.2016 (2016). source

      Not checked in the free run.

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

    Premisecitation

    PNNs surround inhibitory fast spiking parvalbumin-positive GABAergic interneurons and are also associated with excitatory pyramidal neurons in the cerebral cortex.

    “PNNs surround inhibitory fast spiking parvalbumin-positive GABAergic interneurons12–14, but are also associated with further subpopulations, for example excitatory pyramidal neurons in the cerebral cortex15,16.”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [12] Bruckner, G. et al. Cortical areas are revealed by distribution patterns of proteoglycan components and parvalbumin in the Mongolian gerbil and rat. Brain Res 658, 67–86 (1994). source

      Not checked in the free run.

    • cites [13] Hartig, W., Brauer, K. & Bruckner, G. Wisteria floribunda agglutinin-labelled nets surround parvalbumin-containing neurons. Neuroreport 3, 869–872 (1992). source

      Not checked in the free run.

    • cites [14] Dityatev, A. et al. Activity-dependent formation and functions of chondroitin sulfate-rich extracellular matrix of perineuronal nets. Dev Neurobiol 67, 570–588, https://doi.org/10.1002/dneu.20361 (2007). source

      Not checked in the free run.

    • cites [15] Hausen, D. et al. Pyramidal cells ensheathed by perineuronal nets in human motor and somatosensory cortex. Neuroreport 7, 1725–1729 (1996). source

      Not checked in the free run.

    • cites [16] Wegner, F. et al. Diffuse perineuronal nets and modified pyramidal cells immunoreactive for glutamate and the GABA(A) receptor alpha1 subunit form a unique entity in rat cerebral cortex. Exp Neurol 184, 705–714, https://doi.org/10.1016/S0014-4886(03)00313-3 (2003). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The core structure of PNNs consists of chondroitin sulfate proteoglycans of the lectican family, hyaluronan, tenascins, particularly tenascin-R, and link proteins for stabilization.

    “The core structure of PNNs consists of chondroitin sulfate proteoglycans (CSPGs) of the lectican family17,18, hyaluronan19,20, tenascins, particularly tenascin-R (TnR)21,22 and link proteins23,24 for stabilization.”
    Quote in the paperSubstantial claim0 of 6 sources checked
    • cites [17] Deepa, S. S. et al. Composition of perineuronal net extracellular matrix in rat brain: a different disaccharide composition for the net-associated proteoglycans. J Biol Chem 281, 17789–17800, https://doi.org/10.1074/jbc.M600544200 (2006). source

      Not checked in the free run.

    • cites [18] Galtrey, C. M. & Fawcett, J. W. The role of chondroitin sulfate proteoglycans in regeneration and plasticity in the central nervous system. Brain Res Rev 54, 1–18, https://doi.org/10.1016/j.brainresrev.2006.09.006 (2007). source

      Not checked in the free run.

    • cites [19] Yasuhara, O., Akiyama, H., McGeer, E. G. & McGeer, P. L. Immunohistochemical localization of hyaluronic acid in rat and human brain. Brain Res 635, 269–282 (1994). source

      Not checked in the free run.

    • cites [20] Giamanco, K. A. & Matthews, R. T. Deconstructing the perineuronal net: cellular contributions and molecular composition of the neuronal extracellular matrix. Neuroscience 218, 367–384, https://doi.org/10.1016/j.neuroscience.2012.05.055 (2012). source

      Not checked in the free run.

    • cites [21] Morawski, M. et al. Tenascin-R promotes assembly of the extracellular matrix of perineuronal nets via clustering of aggrecan. Philos Trans R Soc Lond B Biol Sci 369, 20140046, https://doi.org/10.1098/rstb.2014.0046 (2014). source

      Not checked in the free run.

    • cites [22] Sorg, B. A. et al. Casting a Wide Net: Role of Perineuronal Nets in Neural Plasticity. J Neurosci 36, 11459–11468, https://doi.org/10.1523/JNEUROSCI.2351-16.2016 (2016). source

      Not checked in the free run.

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

    Premisecitation

    The first study describing the quadruple knockout mouse revealed an upregulation of fibulin-1 and fibulin-2 in the brains of one month old mice.

    “The first study describing this knockout mouse revealed an upregulation of the proteins fibulin-1 and fibulin-2 in the brains of one month old mice28.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] Rauch, U., Zhou, X.-H. & Roos, G. Extracellular matrix alterations in brains lacking four of its components. Biochemical and Biophysical Research Communications 328, 608–617, https://doi.org/10.1016/j.bbrc.2005.01.026 (2005). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Perineuronal nets (PNNs) contribute to the process of synaptogenesis.

    “Although it is known for a few years that PNNs contribute to the process of synaptogenesis, it is not yet clear to which extent the different molecules are involved therein9,10,41.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] Dityatev, A., Schachner, M. & Sonderegger, P. The dual role of the extracellular matrix in synaptic plasticity and homeostasis. Nat Rev Neurosci 11, 735–746, https://doi.org/10.1038/nrn2898 (2010). source

      Not checked in the free run.

    • cites [10] Dzyubenko, E., Gottschling, C. & Faissner, A. Neuron-Glia Interactions in Neural Plasticity: Contributions of Neural Extracellular Matrix and Perineuronal Nets. Neural Plast 2016, 5214961, https://doi.org/10.1155/2016/5214961 (2016). source

      Not checked in the free run.

    • cites [41] Kwok, J. C., Dick, G., Wang, D. & Fawcett, J. W. Extracellular matrix and perineuronal nets in CNS repair. Dev Neurobiol 71, 1073–1089, https://doi.org/10.1002/dneu.20974 (2011). source

      Not checked in the free run.

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

    Study design and conductown data

    The microarray analysis used three dependent hippocampus samples of siblings.

    “using three dependent hippocampus samples of siblings (n = 3)”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    In hippocampal neurons from TnR-deficient mice, PNN organization around dendrites is modified and can be rescued by adding TnR and aggrecan into the culture medium.

    “A recent study concerning hippocampal neurons from TnR-deficient mice reported a modified PNN organization around dendrites that could be rescued by adding TnR and aggrecan into the culture medium21.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Morawski, M. et al. Tenascin-R promotes assembly of the extracellular matrix of perineuronal nets via clustering of aggrecan. Philos Trans R Soc Lond B Biol Sci 369, 20140046, https://doi.org/10.1098/rstb.2014.0046 (2014). source

      Not checked in the free run.

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

    Premisecitation

    Pyramidal neurons in the CA2 region are a major source of perineuronal nets in the hippocampus and are positive for WFA and aggrecan.

    “it has recently been demonstrated that pyramidal neurons in the CA2 region are a major source of perineuronal nets in the hippocampus and positive for WFA and aggrecan33.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Carstens, K. E., Phillips, M. L., Pozzo-Miller, L., Weinberg, R. J. & Dudek, S. M. Perineuronal Nets Suppress Plasticity of Excitatory Synapses on CA2 Pyramidal Neurons. J Neurosci 36, 6312–6320, https://doi.org/10.1523/JNEUROSCI.0245-16.2016 (2016). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Five independent experiments were performed, randomly choosing 20 neurons with and 20 neurons without PNNs per condition, totaling 800 neurons analysed.

    “Five independent experiments (biological replicates N = 5) were performed choosing randomly 20 neurons with (n = 20) and 20 neurons without PNNs (n = 20) per each condition. In sum, 800 neurons were analysed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Maturation of PNNs is significantly delayed in the quadruple knockout hippocampus but normalized after postnatal day 30 to attain wildtype control levels in adulthood.

    “In conclusion, the maturation of PNNs is significantly delayed in the quadruple knockout hippocampus but normalized after postnatal day 30 to attain the wildtype control levels in adulthood”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The observed synaptic, network, PNN and gene-expression phenotypes in the quadruple knockout mouse are caused by the absence of TnC, TnR, brevican and neurocan rather than by compensatory or off-target effects.

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

    Premisecitation

    When hippocampal neurons were treated with chondroitinase ABC (ChABC) in vitro, synapse formation was boosted.

    “When hippocampal neurons were treated with ChABC in vitro, synapse formation was boosted6.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Pyka, M. et al. Chondroitin sulfate proteoglycans regulate astrocyte-dependent synaptogenesis and modulate synaptic activity in primary embryonic hippocampal neurons. Eur J Neurosci 33, 2187–2202, https://doi.org/10.1111/j.1460-9568.2011.07690.x (2011). source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The reduction of inhibitory synapses levelled off after three weeks, where wildtype neurons maintained in the presence of knockout astrocytes displayed an enhanced number of vGAT-positive afferents and inhibitory synapses, irrespective of PNN presence.

    “This effect levelled off after three weeks where wildtype neurons maintained in the presence of knockout astrocytes displayed an enhanced number of vGAT-positive afferents and inhibitory synapses, irrespective of the presence or absence of PNNs (Fig. 2g,h).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The observed synaptic, network, PNN and gene-expression phenotypes in the quadruple knockout mouse are caused by the absence of TnC, TnR, brevican and neurocan rather than by compensatory or off-target effects.

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

    Premisecitation

    One of the main features of the ECM and PNNs is to restrict the formation of neurites and their synapses while protecting neurons towards harmful substances or events.

    “Several studies of the recent years have shown that one of the main features of the ECM and PNNs is to restrict the formation of neurites42 and their synapses with concurrent protection of neurons towards harmful substances or events43.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [42] McKeon, R. J., Schreiber, R. C., Rudge, J. S. & Silver, J. Reduction of neurite outgrowth in a model of glial scarring following CNS injury is correlated with the expression of inhibitory molecules on reactive astrocytes. J Neurosci 11, 3398–3411 (1991). source

      Not checked in the free run.

    • cites [43] Karetko, M. & Skangiel-Kramska, J. Diverse functions of perineuronal nets. Acta Neurobiol Exp (Wars) 69, 564–577 (2009). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Tenascin-R (TnR) is a pivotal constituent of PNNs and its elimination leads to a change of PNN distribution, composition and function.

    “TnR is a pivotal constituent of PNNs and its elimination leads to a change of PNN distribution, composition and function46.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [46] Bruckner, G. et al. Postnatal development of perineuronal nets in wild-type mice and in a mutant deficient in tenascin-R. J Comp Neurol 428, 616–629 (2000). source

      Not checked in the free run.

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

    Study design and conductown data

    Three independent experiments were performed and the PNN area size of four hippocampi was examined.

    “Three independent experiments (biological replicates N = 3) were performed and the PNN area size of four hippocampi (n = 4) was examined.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Spon2 is known to facilitate neurite outgrowth of hippocampal neurons.

    “Spon2 is known to facilitate neurite outgrowth of hippocampal neurons39,40.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [39] Feinstein, Y. et al. F-spondin and mindin: two structurally and functionally related genes expressed in the hippocampus that promote outgrowth of embryonic hippocampal neurons. Development 126, 3637–3648 (1999). source

      Not checked in the free run.

    • cites [40] Feinstein, Y. & Klar, A. The neuronal class 2 TSR proteins F-spondin and Mindin: a small family with divergent biological activities. Int J Biochem Cell Biol 36, 975–980, https://doi.org/10.1016/j.biocel.2004.01.002 (2004). source

      Not checked in the free run.

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

    Premisecitation

    Fibulin-1 mutations are associated with cognitive deficits in humans.

    “Interestingly, fibulin-1 mutations are associated with cognitive deficits in the human and fibulin-2 mediates TGF-beta1 effects on adult neural stem cells50,51.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] Bohlega, S., Al-Ajlan, H. & Al-Saif, A. Mutation of fibulin-1 causes a novel syndrome involving the central nervous system and connective tissues. Eur J Hum Genet 22, 640–643, https://doi.org/10.1038/ejhg.2013.210 (2014). source

      Not checked in the free run.

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

    Study design and conductown data

    RNA quality control ensured samples had an RNA integrity number (RIN) of at least 9.

    “RNA quality control was carried out with the RNA 6000 Nano Assay (Agilent 2100 Bioanalyser) to ensure that the samples had an RNA integrity number (RIN) of at least 9.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The resemblance of adult PNN formation to wildtype indicates a progressive compensation of the four missing ECM molecules, possibly by upregulation of other ECM molecules.

    “In the adult hippocampus, the PNN formation resembled the expression in the wildtype hippocampus, indicating a progressive compensation of the four missing ECM molecules TnC, TnR, brevican and neurocan, possibly by the upregulation of other ECM molecules.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Impaired PNN formation and structure accompanied with altered synaptic plasticity is associated with psychiatric and neurological diseases such as schizophrenia and epilepsy.

    “An impaired PNN formation and structure accompanied with altered synaptic plasticity is associated with a couple of psychiatric and neurological diseases such as schizophrenia and epilepsy, as reviewed recently62.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [62] Soleman, S., Filippov, M. A., Dityatev, A. & Fawcett, J. W. Targeting the neural extracellular matrix in neurological disorders. Neuroscience 253, 194–213, https://doi.org/10.1016/j.neuroscience.2013.08.050 (2013). source

      Not checked in the free run.

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

    Premisecitation

    Grin2d contributes to synaptic transmission of hippocampal interneurons of young mice and of pyramidal CA1 neurons of newborn pups.

    “By using Grin2d-deficient mice, its contribution in synaptic transmission of hippocampal interneurons of young mice as well as of the pyramidal CA1 neurons of newborn pups has been proven65.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [65] von Engelhardt, J. et al. GluN2D-containing NMDA receptors-mediate synaptic currents in hippocampal interneurons and pyramidal cells in juvenile mice. Front Cell Neurosci 9, 95, https://doi.org/10.3389/fncel.2015.00095 (2015). source

      Not checked in the free run.

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

    Premisecitation

    Proteins released by astrocytes influence synaptogenesis, for example thrombospondins and the gabapentin receptor, Hevin and SPARC, or Pentraxin 3 that promotes excitatory synapse formation by fostering clustering of AMPA glutamate receptors.

    “Beyond these PNN-associated compounds also proteins released by astrocytes influence synaptogenesis, for example thrombospondins and the gabapentin receptor55,73, Hevin and SPARC56, or Pentraxin 3 that promotes excitatory synapse formation by fostering the clustering of AMPA glutamate receptors74.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [55] Christopherson, K. S. et al. Thrombospondins are astrocyte-secreted proteins that promote CNS synaptogenesis. Cell 120, 421–433, https://doi.org/10.1016/j.cell.2004.12.020 (2005). source

      Not checked in the free run.

    • cites [73] Eroglu, C. et al. Gabapentin receptor alpha2delta-1 is a neuronal thrombospondin receptor responsible for excitatory CNS synaptogenesis. Cell 139, 380–392, https://doi.org/10.1016/j.cell.2009.09.025 (2009). source

      Not checked in the free run.

    • cites [56] Kucukdereli, H. et al. Control of excitatory CNS synaptogenesis by astrocyte-secreted proteins Hevin and SPARC. Proc Natl Acad Sci USA 108, E440–449, https://doi.org/10.1073/pnas.1104977108 (2011). source

      Not checked in the free run.

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

    Premisecitation

    Gpc4 and Gpc6 are astrocytic factors that stimulate excitatory synapse formation by regulating glutamate receptor clustering.

    “In line with this, Gpc4 and Gpc6 were recently also discovered as astrocytic factors, which stimulate the excitatory synapse formation by regulating glutamate receptor clustering57.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [57] Allen, N. J. et al. Astrocyte glypicans 4 and 6 promote formation of excitatory synapses via GluA1 AMPA receptors. Nature 486, 410–414, https://doi.org/10.1038/nature11059 (2012). source

      Not checked in the free run.

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

    Premisecitation

    Sema4c is known as interaction partner of different PSD95 isoforms in neocortical cultures and in the adult brain of mice.

    “For example, in the quadruple knockout mouse Sema4c is upregulated, which is known as interaction partner of different PSD95 isoforms in neocortical cultures as well as in the adult brain of mice63.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [63] Inagaki, S. et al. Sema4c, a transmembrane semaphorin, interacts with a post-synaptic density protein, PSD-95. J Biol Chem 276, 9174–9181, https://doi.org/10.1074/jbc.M009051200 (2001). source

      Not checked in the free run.

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

    Premisecitation

    Cplx3 regulates synaptic neurotransmitter release of both excitatory and inhibitory synapses.

    “Cplx3 that was significantly downregulated in the quadruple knockout hippocampus regulates the synaptic neurotransmitter release of both excitatory and inhibitory synapses64.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [64] Xue, M. et al. Complexins facilitate neurotransmitter release at excitatory and inhibitory synapses in mammalian central nervous system. Proc Natl Acad Sci USA 105, 7875–7880, https://doi.org/10.1073/pnas.0803012105 (2008). source

      Not checked in the free run.

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

    Premisecitation

    Neurons coated with PNNs were characterized by an attenuated synapse number after both 14 and 21 DIV.

    “Neurons coated with PNNs were characterized by an attenuated synapse number after both 14 and 21 DIV29.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Geissler, M. et al. A. Primary hippocampal neurons, which lack four crucial extracellular matrix molecules, display abnormalities of synaptic structure and function and severe deficits in perineuronal net formation. The Journal of Neuroscience 33, 7742–7755, https://doi.org/10.1523/JNEUROSCI.3275-12.2013 (2013). source

      Not checked in the free run.

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

    Premisecitation

    Grin2d is found in hippocampal interneurons and enhances their activity due to its involvement in synaptic transmission.

    “Furthermore, Grin2d has been found in hippocampal interneurons and enhances their activity due to its involvement in synaptic transmission66.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [66] Perszyk, R. E. et al. GluN2D-Containing N-methyl-d-Aspartate Receptors Mediate Synaptic Transmission in Hippocampal Interneurons and Regulate Interneuron Activity. Mol Pharmacol 90, 689–702, https://doi.org/10.1124/mol.116.105130 (2016). source

      Not checked in the free run.

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

    Premisecitation

    TnR is associated with HNK-1 and necessary for the maintenance of the excitatory and inhibitory balance in CA1 region.

    “TnR, another protein missing in the quadruple knockout mouse is known to be associated with HNK-1 and necessary for the maintenance of the excitatory and inhibitory balance in CA1 region47.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] Saghatelyan, A. K. et al. Reduced perisomatic inhibition, increased excitatory transmission, and impaired long-term potentiation in mice deficient for the extracellular matrix glycoprotein tenascin-R. Mol Cell Neurosci 17, 226–240, https://doi.org/10.1006/mcne.2000.0922 (2001). source

      Not checked in the free run.

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

    Premisecitation

    Especially CA2 excitatory pyramidal neurons are surrounded by PNNs.

    “A recent study demonstrated that especially the CA2 excitatory pyramidal neurons are surrounded by PNNs.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Carstens, K. E., Phillips, M. L., Pozzo-Miller, L., Weinberg, R. J. & Dudek, S. M. Perineuronal Nets Suppress Plasticity of Excitatory Synapses on CA2 Pyramidal Neurons. J Neurosci 36, 6312–6320, https://doi.org/10.1523/JNEUROSCI.0245-16.2016 (2016). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    TnR is mainly expressed by oligodendrocytes and not by astrocytes.

    “However, TnC is not a major component of perineuronal nets52 while TnR is mainly expressed by oligodendrocytes and not by astrocytes10 (and is only present at low concentration in the co-culture of WT astrocytes with KO neurons, if at all.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] Dzyubenko, E., Gottschling, C. & Faissner, A. Neuron-Glia Interactions in Neural Plasticity: Contributions of Neural Extracellular Matrix and Perineuronal Nets. Neural Plast 2016, 5214961, https://doi.org/10.1155/2016/5214961 (2016). source

      Not checked in the free run.

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

    Study design and conductnone given

    The present study was carried out in accordance with the European Council Directive 2010/63/EU and approved by the animal care committee of North Rhine-Westphalia.

    “The present study was carried out in accordance with the European Council Directive of September 22, 2010 (2010/63/EU) for care of laboratory animals and approved by the animal care committee of North Rhine-Westphalia, Germany, based at the LANUV (Landesamt für Umweltschutz, Naturschutz und Verbraucherschutz, Nordrhein-Westphalen, D-45659 Recklinghausen, Germany).”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Neurocan influences the binding of neural cell adhesion molecule (NCAM) and ephrin type-A receptor 3 (EPHA3) at perisomatic synapses.

    “Neurocan is known to influence the binding of neural cell adhesion molecule (NCAM) and ephrin type-A receptor 3 (EPHA3) at perisomatic synapses72.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [72] Sullivan, C. S. et al. Perineuronal Net Protein Neurocan Inhibits NCAM/EphA3 Repellent Signaling in GABAergic Interneurons. Sci Rep 8, 6143, https://doi.org/10.1038/s41598-018-24272-8 (2018). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    CSPGs like aggrecan or brevican are incorporated into perineuronal nets through their interaction with TnR and hyaluronic acid.

    “Several reports suggest that CSPGs like aggrecan or brevican are incorporated into perineuronal nets through their interaction with TnR and hyaluronic acid14,53,54.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [14] Dityatev, A. et al. Activity-dependent formation and functions of chondroitin sulfate-rich extracellular matrix of perineuronal nets. Dev Neurobiol 67, 570–588, https://doi.org/10.1002/dneu.20361 (2007). source

      Not checked in the free run.

    • cites [53] Lundell, A. et al. Structural basis for interactions between tenascins and lectican C-type lectin domains: evidence for a crosslinking role for tenascins. Structure 12, 1495–1506, https://doi.org/10.1016/j.str.2004.05.021 (2004). source

      Not checked in the free run.

    • cites [54] Hagihara, K. et al. Immunohistochemical evidence for the brevican-tenascin-R interaction: colocalization in perineuronal nets suggests a physiological role for the interaction in the adult rat brain. J Comp Neurol 410, 256–264 (1999). source

      Not checked in the free run.

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

    Premisecitation

    Fibulin-2 mediates TGF-beta1 effects on adult neural stem cells.

    “Interestingly, fibulin-1 mutations are associated with cognitive deficits in the human and fibulin-2 mediates TGF-beta1 effects on adult neural stem cells50,51.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [51] Radice, P. D. et al. Fibulin-2 is a key mediator of the pro-neurogenic effect of TGF-beta1 on adult neural stem cells. Mol Cell Neurosci 67, 75–83, https://doi.org/10.1016/j.mcn.2015.06.004 (2015). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A recently published study demonstrated altered synaptic plasticity in the dorsal dentate gyrus of the quadruple knockout hippocampus that translated into enhanced short-term depression in conjunction with modified frequency-dependence in vivo.

    “A recently published study has demonstrated an altered synaptic plasticity in the dorsal dentate gyrus of the quadruple knockout hippocampus that translated into an enhanced short-term depression in conjunction with a modified frequency-dependence in vivo30.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30] Jansen, S., Gottschling, C., Faissner, A. & Manahan-Vaughan, D. Intrinsic cellular and molecular properties of in vivo hippocampal synaptic plasticity are altered in the absence of key synaptic matrix molecules. Hippocampus 27, 920–933, https://doi.org/10.1002/hipo.22742 (2017). source

      Not checked in the free run.

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

    Premisecitation

    PNNs have been proposed as indispensable mediators of the modulation of synaptic plasticity by the transcription factor Otx2.

    “Interestingly, PNNs have been proposed as indispensable mediators of the modulation of synaptic plasticity by the transcription factor Otx259–61.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [59] Beurdeley, M. et al. Otx2 binding to perineuronal nets persistently regulates plasticity in the mature visual cortex. J Neurosci 32, 9429–9437, https://doi.org/10.1523/JNEUROSCI.0394-12.2012 (2012). source

      Not checked in the free run.

    • cites [60] Spatazza, J. et al. Choroid-plexus-derived Otx2 homeoprotein constrains adult cortical plasticity. Cell Rep 3, 1815–1823, https://doi.org/10.1016/j.celrep.2013.05.014 (2013). source

      Not checked in the free run.

    • cites [61] Bernard, C. et al. Graded Otx2 activities demonstrate dose-sensitive eye and retina phenotypes. Hum Mol Genet 23, 1742–1753, https://doi.org/10.1093/hmg/ddt562 (2014). source

      Not checked in the free run.

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

    Premisecitation

    Brevican controls the location of AMPA and potassium channels and might therefore affect synapse dynamics.

    “Brevican for example, which is missing in our mouse model controls the location of AMPA and potassium channels and might therefore affect synapse dynamics71.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [71] Favuzzi, E. et al. Activity-Dependent Gating of Parvalbumin Interneuron Function by the Perineuronal Net Protein Brevican. Neuron 95, 639–655 e610, https://doi.org/10.1016/j.neuron.2017.06.028 (2017). source

      Not checked in the free run.

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

    Study design and conductnone given

    All efforts were made to reduce the number of animals in the experiments.

    “All efforts were made to reduce the number of animals in the experiments.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Hippocampal neurons in culture after ChABC treatment show higher excitability.

    “These data are in agreement with the report of Dityatev and colleagues who found a higher excitability of hippocampal neurons in culture after ChABC treatment14.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Dityatev, A. et al. Activity-dependent formation and functions of chondroitin sulfate-rich extracellular matrix of perineuronal nets. Dev Neurobiol 67, 570–588, https://doi.org/10.1002/dneu.20361 (2007). source

      Not checked in the free run.

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

    Premisecitation

    A prominent PNN-positive area is found in the CA2 region of the hippocampus.

    “A prominent PNN-positive area was found in the CA2 region of the hippocampus33.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Carstens, K. E., Phillips, M. L., Pozzo-Miller, L., Weinberg, R. J. & Dudek, S. M. Perineuronal Nets Suppress Plasticity of Excitatory Synapses on CA2 Pyramidal Neurons. J Neurosci 36, 6312–6320, https://doi.org/10.1523/JNEUROSCI.0245-16.2016 (2016). source

      Not checked in the free run.

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

    Study design and conductown data

    The whole-transcript expression analysis was performed in triplicates.

    “Using Affymetrix GeneChip® Mouse Gene 2.0 ST Arrays, a whole-transcript expression analysis of >30,000 RefSeq transcripts of P21 hippocampus of wildtype and quadruple knockout mice siblings was performed in triplicates.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The excitation versus inhibition balance is considered very important in the context of neuropsychiatric disease.

    “The excitation versus inhibition balance is considered very important in the context of neuropsychiatric disease67.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] Sohal, V. S. & Rubenstein, J. L. R. Excitation-inhibition balance as a framework for investigating mechanisms in neuropsychiatric disorders. Mol Psychiatry, https://doi.org/10.1038/s41380-019-0426-0 (2019). source

      Not checked in the free run.

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

    Premisecitation

    A shift of the excitation/inhibition balance can result from neurodevelopmental abnormalities targeting inhibitory interneurons or from structural changes at the synapse.

    “A shift of the balance can result from neurodevelopmental abnormalities targeting the inhibitory interneurons68 or from structural changes at the synapse69.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [68] Lopatina, O. L. et al. Excitation/inhibition imbalance and impaired neurogenesis in neurodevelopmental and neurodegenerative disorders. Rev Neurosci, https://doi.org/10.1515/revneuro-2019-0014 (2019). source

      Not checked in the free run.

    • cites [69] Howell, B. W. & Smith, K. M. Synaptic structural protein dysfunction leads to altered excitation inhibition ratios in models of autism spectrum disorder. Pharmacol Res 139, 207–214, https://doi.org/10.1016/j.phrs.2018.11.019 (2019). source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The in vivo PNN formation results fit with the in vitro findings, both demonstrating a diminished PNN formation in the postnatal quadruple knockout mouse.

    “The results found for the in vivo PNN formation fit perfectly with the in vitro findings29, both demonstrating a diminished PNN formation in the postnatal quadruple knockout mouse.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Geissler, M. et al. A. Primary hippocampal neurons, which lack four crucial extracellular matrix molecules, display abnormalities of synaptic structure and function and severe deficits in perineuronal net formation. The Journal of Neuroscience 33, 7742–7755, https://doi.org/10.1523/JNEUROSCI.3275-12.2013 (2013). source

      Not checked in the free run.

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

    Premisecitation

    When mice were kept in an enriched environment, PNN expression was enhanced, indicating a correlation between PNN development and environmental stimuli within the juvenile brain.

    “When mice were kept in an enriched environment, the PNN expression was enhanced, indicating a correlation between PNN development and environmental stimuli within the juvenile brain33.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Carstens, K. E., Phillips, M. L., Pozzo-Miller, L., Weinberg, R. J. & Dudek, S. M. Perineuronal Nets Suppress Plasticity of Excitatory Synapses on CA2 Pyramidal Neurons. J Neurosci 36, 6312–6320, https://doi.org/10.1523/JNEUROSCI.0245-16.2016 (2016). source

      Not checked in the free run.

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

    Premisecitation

    Astrocyte-secreted factors thrombospondin and hevin lead to the development of structural, but silent synapses.

    “In former studies, it was demonstrated that the astrocyte-secreted factors thrombospondin and hevin lead to the development of structural, but silent synapses55,56.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [55] Christopherson, K. S. et al. Thrombospondins are astrocyte-secreted proteins that promote CNS synaptogenesis. Cell 120, 421–433, https://doi.org/10.1016/j.cell.2004.12.020 (2005). source

      Not checked in the free run.

    • cites [56] Kucukdereli, H. et al. Control of excitatory CNS synaptogenesis by astrocyte-secreted proteins Hevin and SPARC. Proc Natl Acad Sci USA 108, E440–449, https://doi.org/10.1073/pnas.1104977108 (2011). source

      Not checked in the free run.

64 of 64

  • The paper relies on this without support.

    The observed synaptic, network, PNN and gene-expression phenotypes in the quadruple knockout mouse are caused by the absence of TnC, TnR, brevican and neurocan rather than by compensatory or off-target effects.

    “the quadruple knockout mouse, which lacks the four ECM components TnC, TnR, neurocan and brevican”

  • The paper relies on this without support.

    Astrocytes in vitro secrete brevican, neurocan and TnC.

    “Astrocytes in vitro secrete brevican, neurocan and TnC.”
2 of 2

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?

  • In general, there is an overall increase in network activity when PNNs are depleted or attenuated.

    “However, in general, there is an overall increase in network activity when PNNs are depleted or attenuated [53, 59, 68], possibly due to an overall reduction in inhibitory activity.”

    From The extracellular matrix and perineuronal nets in memory (2022) · cites this paper as [68]

    The Results section, “Higher neuronal network activity in the quadruple knockout mouse” (page unavailable), reports increased spontaneous activity in cultured hippocampal networks when both neurons and astrocytes lacked four extracellular-matrix molecules. The claim generalizes this finding to PNN depletion or attenuation in general, but the paper reports that knockout neurons cultured with wildtype astrocytes did not show the same increase in spike number. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Structural modification of perineuronal nets alters synaptic transmission, synapse number, and the ion channel/neurotransmitter receptor composition of synapses.

    “the structural modification of PNNs alters synaptic transmission [27], synapse number [28], and the ion channel/neurotransmitter receptor composition of synapses [29]”

    From Microglia facilitate loss of perineuronal nets in the Alzheimer's disease brain (2020) · cites this paper as [28]

  • Genetic ablation of PNN structural components and consequent loss of neuronal PNN integrity can induce loss of synapses and impaired synaptic colocalization/expression of neurotransmitter receptor subunits, potentially manifesting as deficits in synaptic plasticity.

    “This may be due in part to the degradation of the PNNs in which synapses are embedded, as the genetic ablation of one or more PNN structural components and consequent loss of neuronal PNN integrity can induce the loss of synapses [28, 80] and impaired synaptic colocalization/expression of neurotransmitter receptor subunits [29], potentially manifesting as deficits in synaptic plasticity (e.g. LTP)”

    From Microglia facilitate loss of perineuronal nets in the Alzheimer's disease brain (2020) · cites this paper as [28]

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.

  • Significant burst-duration change is also described as unchanged

    Major

    The figure caption says mean burst duration remained unchanged between knockout and control cultures, but the results report a significant difference between those conditions at 21 DIV.

  • A p-value below the stated threshold is called nonsignificant

    Minor

    The vGAT result is described as not significant despite p = 0.028, which is below the paper's stated significance threshold of p ≤ 0.05.

  • Prior study is said to show both reduced and enhanced short-term depression

    Minor

    The introduction and discussion give opposite directions for the short-term depression reported by the cited study.

  • Inhibitory synapses are described as reduced in all mutant-cell conditions despite an increase

    Minor

    The broad statement that structural inhibitory synapses were reduced in all conditions involving mutant cells conflicts with the reported significant increase at 21 DIV in wildtype neurons cultured with knockout astrocytes.

  • Reported regulated genes fall below the stated fold-change cutoff

    Minor

    The methods require a change greater than 1.5-fold for a transcript to be called regulated, yet several genes are described as significantly changed at smaller fold changes, including Cript at 1.05-fold.

5 of 5

The citation lists haven’t been fetched yet

References 78 · Cited by 111

Authors
Gottschling, C., Wegrzyn, D., Denecke, B., & Faissner, A.
Affiliations
  • Ruhr University Bochum (DE)
  • RWTH Aachen University (DE)
ORCID
Faissner, Andreas
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2019-09-26
Volume
9
Issue
1
Pages
13939-13939
ISSN
2045-2322 (ISSN-L)
DOI
10.1038/s41598-019-50404-9
PMC
PMC6763627
OpenAlex
W2975653464
Semantic Scholar
858b3f63e31a7311eefb60c28a2150c3cbc11ac5
Cited by
111
References
78
Citations by year
2026: 7 · 2025: 18 · 2024: 15 · 2023: 17 · 2022: 16 · 2021: 26 · 2020: 12
FWCI
6.45
Type
journal article
Language
en
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • Dokumentenrepositorium der RUB (Ruhr University Bochum) (submittedVersion, cc-by)
  • RWTH Publications (RWTH Aachen) (submittedVersion, other-oa)
Funders
Deutsche Forschungsgemeinschaft (SPP 1172/3 FA 159/13-3, FA 159/22-1)
Topics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neuropharmacology Research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Proteoglycans and glycosaminoglycans research
  • Life Sciences › Neuroscience › Developmental Neuroscience › Neurogenesis and neuroplasticity mechanisms
Keywords
perineuronal nets, extracellular matrix, tenascin-C, tenascin-R, brevican, neurocan, hippocampus, gene expression, astrocytes
MeSH terms
Animals, Cells, Cultured, Female, Male, Nerve Tissue Proteins, Proteoglycans, Synapses, Gene Deletion, Tenascin, Excitatory Postsynaptic Potentials, Mice, Inhibitory Postsynaptic Potentials, CA2 Region, Hippocampal, Neurocan, Brevican

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 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

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.

What counts as a claim ›How we measure confidence ›How we check this ›

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