Experience-dependent development of perineuronal nets and chondroitin sulfate proteoglycan receptors in mouse visual cortex

Matrix Biology 32 (2013) 352–363

Contents lists available at ScienceDirect

Matrix Biology journal homepage: www.elsevier.com/locate/matbio

Experience-dependent development of perineuronal nets and chondroitin sulfate proteoglycan receptors in mouse visual cortex Qian Ye a, b, Qing-long Miao b,⁎ a b

School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 1954 Hua-Shan Road, Shanghai 200030, China Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China

a r t i c l e

i n f o

Article history: Received 30 July 2012 Received in revised form 18 March 2013 Accepted 1 April 2013 Keywords: Perineuronal net Parvalbumin interneuron CSPG receptor Critical period plasticity Mouse visual cortex

a b s t r a c t Perineuronal nets (PNNs) are extracellular matrix structures consisting of chondroitin sulfate proteoglycans (CSPGs), hyaluronan, link proteins and tenascin-R (Tn-R). They enwrap a subset of GABAergic inhibitory interneurons in the cerebral cortex and restrict experience-dependent cortical plasticity. While the expression profile of PNN components has been widely studied in many areas of the central nervous system of various animal species, it remains unclear how these components are expressed during the postnatal development of mouse primary visual cortex (V1). In the present study, we characterized the developmental time course of the formation of PNNs in the mouse primary visual cortex, using the specific antibodies against the two PNN component proteins aggrecan and tenascin-R, or the lectin Wisteria floribunda agglutinin (WFA) that directly binds to glycosaminoglycan chains of chondroitin sulfate proteoglycans (CSPGs). We found that the fluorescence staining signals of both the WFA staining and the antibody against aggrecan rapidly increased in cortical neurons across layers 2–6 during postnatal days (PD) 10–28 and reached a plateau around PD42, suggesting a full construction of PNNs by the end of the critical period. Co-staining with antibodies to Ca2+ binding protein parvalbumin (PV) demonstrated that the majority of PNN-surrounding cortical neurons are immunoreactive to PV. Similar expression profile of another PNN component tenascin-R was observed in the development of V1. Dark rearing of mice from birth significantly reduced the density of PNN-surrounding neurons. In addition, the expression of two recently identified CSPG receptors — Nogo receptor (NgR) and leukocyte common antigen-related phosphatase (LAR), showed significant increases from PD14 to PD70 in layer 2–6 of cortical PV-positive interneurons in normal reared mice, but decreased significantly in dark-reared ones. Taken together, these results suggest that PNNs form preferentially in cortical PV-positive interneurons in an experience-dependent manner, and reach full maturation around the end of the critical period of V1 development. © 2013 Elsevier B.V. All rights reserved.

1. Introduction Perineuronal nets (PNNs) are extracellular matrix structures consisting of chondroitin sulfate proteoglycans (CSPGs), hyaluronan, link proteins and tenascin-R (Tn-R) (Koppe et al., 1997b; Deepa et al., 2006; Carulli et al., 2007; Kwok et al., 2010). The major CSPGs include aggrecan, versican, neurocan, brevican, phosphacans, and NG2 (Matsui et al., 1998; Hagihara et al., 1999; Carulli et al., 2006). CSPGs comprise of a single protein core and varying numbers of

Abbreviations: CSPGs, chondroitin sulfate proteoglycans; ECM, extracellular matrix; GAG, glycosaminoglycan; GABA, γ-aminobutyric acid; HA, hyaluronan; LAR, leukocyte common antigen-related phosphatase; NgR, nogo receptor; NGS, normal goat serum; OD, ocular dominance; Otx2, orthodenticle homeobox 2; PD, postnatal days; PFA, paraformaldehyde; PNN(s), perineuronal net(s); PV, parvalbumin; Tn-R, tenascin-R; V1, primary visual cortex; WFA, Wisteria floribunda agglutinin. ⁎ Corresponding author at: Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China. Fax: +86 21 54921735. E-mail address: [email protected] (Q. Miao). 0945-053X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matbio.2013.04.001

polysaccharide glycosaminoglycan (GAG) chains (Fisher et al., 2011; Wang and Fawcett, 2012). Aggrecan is present in all PNNs while neurocan, versican and phosphacan/RPTPb are present in some but not all PNNs. The expression of link protein and aggrecan mRNA is up-regulated at the time of PNN formation during postnatal development, suggesting a role in triggering PNN formation (Galtrey et al., 2008). Differential glycosylation of aggrecan contributes to a great degree to the molecular heterogeneity of perineuronal nets (Matthews et al., 2002). The visual cortex has the ability to undergo experience-driven plastic changes in early postnatal development during a so-called critical period, after which its plasticity declines with age. With respect to the molecular mechanisms underlying the restriction of critical period plasticity, the observation that PNNs preferentially envelope a specific population of GABAergic inhibitory interneurons is of particular interest as these matrices transform from largely soluble complexes of proteins during prenatal and early postnatal development into highly insoluble complexes by the end of the critical period, a process that is thought to stabilize synaptic structure, thereby

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

decrease synaptic plasticity (Hockfield et al., 1990; Celio and Blumcke, 1994; Wang and Fawcett, 2012). In favor of this hypothesis, enzymatic degradation of the key ECM components, chondroitin sulfate proteoglycans (CSPGs), reactivated ocular dominance plasticity in adult rats (Pizzorusso et al., 2002) and also enabled structural and functional recovery from early monocular deprivation in adult rats (Pizzorusso et al., 2006), results that suggest these molecules play an essential role in the age-dependent decrease in ocular dominance (OD) plasticity. In the cat visual system, the formation of PNNs in postnatal development detected by the monoclonal antibody Cat-301 correlates with a decline in experience-dependent plasticity and the termination of the critical period (Sur et al., 1988). This correlation indicates that PNNs play a role in synapse stabilization and maturation (Zaremba et al., 1989). Moreover, PNN formation is also dependent on appropriate sensory input. Visual deprivation in early development results in reduced PNN formation in the visual system (Sur et al., 1988; Guimaraes et al., 1990; Kind et al., 1995; Lander et al., 1997) but has no effect in the adult (Sur et al., 1988). These results suggest that PNNs play an important role in developmental cortical plasticity. Further studies on the molecular composition of these nets in area 17 demonstrated that aggrecan, a core component of PNNs detected with the monoclonal antibody Cat-301 has an expression profile that is approximately the inverse of the time course of experiencedependent plasticity in the visual cortex and that this expression is experience-dependent in the extragranular layers but not in layer 4. Because experience-dependent developmental plasticity is well established in the mouse visual cortex (Gordon and Stryker, 1996; Espinosa and Stryker, 2012), we used this system to more thoroughly investigate the roles of PNNs and the expression of specific PNN components, for the purpose of gaining additional insight into the role of PNNs in experience-dependent developmental cortical plasticity. First, we examined the expression and the distribution of PNN in the developing visual cortex in normal and dark reared mice, by performing histochemical staining with wisteria floribunda agglutinin (WFA), which has affinity for N-acetylgalactosamine (Bruckner et al., 1993; Schweizer et al., 1993; Matsui et al., 1998). We then used anti-aggrecan and anti-tenascin-R antibodies to visualize PNNs simultaneously (Kind et al., 2013). As most of the cortical neurons possessing PNN use γ-aminobutyric acid (GABA) as a neurotransmitter (Kosaka and Heizmann, 1989; Bruckner et al., 1994; Pizzorusso et al., 2002), we also co-stained the cortical neurons with an antibody against parvalbumin (PV), a protein marker of one class of cortical inhibitory interneurons that are major players in regulating the critical period of visual cortex development (Celio, 1986; Ren et al., 1992). Finally, we examined PNN in dark-reared mice after the closure of the critical period, in order to understand whether visual experience has an impact on the development of PNN. During the last several decades, there have been many studies on the involvement of PNNs in neuronal plasticity, with developmental behavior and functional correlations (Wang and Fawcett, 2012). However, the mechanisms by which PNNs affect neuronal plasticity remain elusive. One possible mechanism is that CSPGs could inhibit axonal sprouting and growth (Oohira et al., 1991; Grumet et al., 1996; Snow et al., 1996; Fitch and Silver, 1997; McKeon et al., 1999; Niederost et al., 1999; Asher et al., 2000). It is reported that most axonal growth inhibitors restrict axonal elongation via interactions with their receptor proteins (Klein, 2004; Liu et al., 2006), so it is very likely that CSPGs suppress neuronal growth primarily through binding and activating functional receptors. Recent works have identified PTPσ (Shen et al., 2009), the Nogo receptor (NgR) (Dickendesher et al., 2012) and leukocyte common antigen-related phosphatase (LAR) (Fisher et al., 2011) as receptors for CSPGs. Here, we investigated the expression and the distribution of NgR and LAR by performing immunohistochemistry staining in the developing mouse visual cortex in normal and dark-reared mice to gain additional insight into the transduction of

353

ECM signals from extracellular to intracellular space and their role in experience-dependent developmental cortical plasticity. We further explored whether the expression of NgR and LAR is dependent on visual experience by rearing the animals in total darkness from birth. 2. Results 2.1. Experience-dependent Development of PNN in Mouse V1 2.1.1. Development of PNN-enveloped Cells in Mouse V1 To characterize the time course of the formation of PNNs in the mouse visual cortex during postnatal brain development, we applied WFA (wisteria floribunda agglutinin), a frequently used lectin that specifically detects N-acetylgalactosamine of polysaccharide glycosaminoglycan (GAG) chains of chondroitin sulfate proteoglycans (CSPGs) to label the PNN formations (Hartig et al., 1992). These nets are known to aggregate to surround neuronal cell bodies and extend along their dendrites (Foscarin et al., 2011). The intensity of this labeling varied among neurons due to the variation in expression levels of CSPGs in different PNNs. With this PNN staining approach, we found that in the mouse visual cortex at PD10, very few cortical cells were stained with the WFA labeling (Fig. 1A), and only a small portion of cortical neurons across the cortical layers were wrapped with PNNs by PD14 (Fig. 1B). A significant increase in the density of PNN-positive neurons was found between PD14 and PD28 (Fig. 1B and C, P b 0.001, one-way ANOVA), while there was also a relatively smaller elevation in the PNN-wrapped cell density between PD28 and PD42 (Fig. 1C and D). The density reached a plateau around PD42, not increasing further until PD70 (Fig. 1D and E, P = 0.75, one-way ANOVA). As shown by statistical results in Fig. 1F, the mean density of PNN-wrapped neurons in the developing visual cortex showed a trend of increase from PD14 through PD42. With more detailed analysis in each cortical layer, we found a similar trend in the PNN maturation (Fig. 1G). Around PD42, layer 4 possessed the highest relative density (312.33 ± 9.32 nets⁄mm 2, n = 30 sections from 6 mice), while layer 2/3 and layer 6 had the lowest densities (Fig. 1G). Thus, our WFA staining results in the visual cortex at different postnatal ages suggest that PNN formation in cortical neurons starts to appear between PD10 and PD14, and reaches maturation around PD42 with a stable expression and distribution of PNNs among cortical neurons. The late maturation course of PNNs in V1 correlates well with the process of the critical period of visual cortical functions (Hensch, 2005). The above observed increase in the number of PNN-wrapped cortical cells in the developing visual cortex (Fig. 1) may have resulted from the increase in total cell number over the postnatal development. To rule out this possibility, we calculated the cortical cell density by counting DAPI-staining cells in the same area of the visual cortex at PD14, 28, 42 and 70, respectively, using the auto-counting toolbox in ImageJ. We found that there was little change in the overall cell density or the density within individual cortical layers over the PD14-70 (Fig. S1). This result confirms that the maturation of PNN formation in the developing visual cortex is accompanied by the increase in density of PNN-enveloped cortical cells in all cortical layers. 2.1.2. Development of PV-positive Neurons in Mouse V1 PNNs detected by WFA frequently envelop a specific subset of GABAergic interneurons expressing the calcium-binding protein parvalbumin (PV). To further investigate the construction of PNNs, we co-stained PV with specific antibodies. Consistent with previous reports (del Rio et al., 1994; Huang et al., 1999; Mukhopadhyay et al., 2009), PV expression was not found in cortical neurons at PD10 (Fig. 2A), but emerged in the soma of scattered non-pyramidal neurons around PD14 (Fig. 2B). The mean density of PV-containing cell increased substantially between PD14 and PD42, and reached a stable pattern around PD42 (Fig. 2B–E). One-way ANOVA analysis of

354

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

Fig. 1. Development of PNN-enveloped cells in V1. A–E: Fluorescence staining of WFA (red) in cortical cells of mouse visual cortex at postnatal days 10, 14, 28, 42 and 70. Scale bar: 200 μm. F–G: Developmental changes in the density (mean ± S.E.M.) of WFA-stained cells in the whole cortical area (F) and in individual layers (G) of the visual cortex during PD10-70. *P b 0.05, **P b 0.01, ***P b 0.001; one-way ANOVA.

developmental changes in the density of PV-containing cells indicated that during the development of the visual cortex, the mean density increased until PD42 (Fig. 2F). Moreover, a similar developmental trend was presented for each layer (Fig. 2G) except for layer 2/3 in which a plateau in the density of PV-containing cell was observed at PD14. Around PD42, layers 4 and 5 had the highest and second highest densities (layer 4: 313.31 ± 8.60 cells⁄mm2; layer 5: 245.94 ± 8.05 cells/mm2; n = 15 from 3 mice), respectively, while the densities in layers 2/3 and 6 were two-fold lower (Fig. 2D and G). Given that there is no change in the density of total cell numbers (Fig. S1), the increased density of PV-containing cells in the developing visual cortex reflected a

maturation process of these cortical inhibitory cells during postnatal development. 2.1.3. Co-localization of PNN-enveloped and PV-containing Cells in V1 Co-staining with WFA and PV antibodies showed that most cortical PV-containing cells in the adult visual cortex (at PD70) possessed surrounding WFA-binding PNNs, while only a small fraction of cortical cells did not show any co-localization of these two chemical components (Fig. 3A–C). The overall density of cortical PV-positive cells enveloped by PNNs was 140.16 ± 4.84 cells⁄mm 2 at PD70, and the ratio of PV- and PNN-containing cells to all PNN-enveloped cells

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

355

Fig. 2. Developmental changes in the density of PV-containing cells in V1. A–E: Immunolabeling of intracellular PV proteins (green) in cortical cells of the mouse visual cortex at postnatal days 10, 14, 28, 42 and 70. Scale bar: 200 μm. F–G: Developmental changes in the density (mean ± S.E.M.) of PV-containing cells in the whole cortical area (F) and per layer (G) of the visual cortex during PD10-70. ***P b 0.001; one-way ANOVA.

was 81.89% ± 1.26% (n = 20 from 4 mice) in adulthood. Moreover, the latter co-localization ratio apparently varied among cortical layers: layers 5 and 6 showed the highest co-localization rates (layer 5: 90.91% ± 2.14%; layer 6: 89.89% ± 2.92%), whereas layers 4 and 2/3 had lower rates (layer 4: 72.29% ± 2.36%; layer 2/3: 78.77% ± 3.05%) at PD70 (Fig. 3D). These results indicate that the PNNs are preferentially formed in the cortical PV-containing inhibitory neurons. 2.1.4. Effects of Dark Rearing on PNN and PV Staining Cells We further examined whether the maturation of PNNs in visual cortical cells depends on early visual experience. Mice were raised

in total darkness from birth through PD41 to achieve complete deprivation of visual experience. In the visual cortex of the dark-reared mice, we found that the overall densities of PNN-enwrapped cells and PV-containing cells were substantially reduced, with respect to that of normal mice (Fig. 4A). However, no significant difference in the soma size and the exuberance of neuritis between these two groups was observed (data not shown). Moreover, with more detailed analysis of each layer, we observed a similar reduction of density of PV-containing and PNN-enwrapped cells after dark rearing, but this reduction varied by cortical layers. For example, layer 4 showed a relatively larger decrease in the density of PV-containing cell (Fig. 4C)

356

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

Fig. 3. Co-localization of PNNs and PV proteins in V1 cortical cells. Double labeling of coronal sections through V1 showing that PNNs mainly ensheathe PV-containing neurons. A–C: Fluorescence staining of WFA (red, A), PV (green, B) and double-staining (merged color, C) in visual cortical cells at PD70. Scale bar: 100 μm. D: Percentage of double-labeled cells in the PNN-enveloped cortical cells in each layer of the visual cortex at PD70.

but no change in the density of PNN-enwrapped cell (Fig. 4B) after dark rearing. These results indicate that dark rearing could significantly hamper the maturation of both PNN-enwrapped and normal dark

A density (/mm2)

200

***

***

PNN

PV

100

0

normal dark

PNN density (/mm2)

B 300 ** 200 **

*

100

0

er

lay

2/3

PV density (/mm2)

C

er

lay

4

er

lay

5

er

lay

6

normal dark

*** 300

*

200 *

** 100

0

er

lay

2/3

er

lay

4

er

lay

5

er

lay

6

Fig. 4. Dark-rearing reduced the density of PV-containing and PNN-enveloped cells in V1 at PD41. A: A comparison of the overall cell density of PV-containing and PNN-enveloped cells in the visual cortex between normal and dark-reared mice (at PD41). Data are presented as mean ± S.E.M., *P b 0.05, **P b 0.01, ***P b 0.001; one-way ANOVA. B and C: similar to A except that the comparisons of the cell density of PNN-enveloped (B) and PV-containing cells (C) were made for individual cortical layers.

PV-containing inhibitory cells in the developing visual cortex. Given the preferential formation of PNNs around PV-containing cortical cells (Fig. 3), our results also imply that the experience-dependent development of PNNs is involved in regulating the maturation of cortical PV-containing cells. 2.1.5. Experience-dependent Development of Aggrecan in Mouse V1 Previous work has shown that aggrecan is present in almost all PNNs (Galtrey et al., 2008), and it is a key activity-regulated component of PNNs (McRae et al., 2007). Here, we investigated the developmental profile of aggrecan expression in V1 in normal and dark reared mice by using the anti-aggrecan antibody. We found that the density of aggrecan-positive neurons in V1 increased gradually from PD14 to PD70, the density approximately doubling from PD28 to PD70 (Fig. 5A, B, and D). Quantitative analysis of aggrecan expression in each cortical layer showed a similar trend (Fig. 5G and H). Around PD70, layer 4 possessed the highest density (324.29 ± 16.33 nets⁄mm2, n = 9 sections from 3 mice), while layer 2/3 and layer 6 had the lowest densities (Fig. 5H). These results demonstrated that aggrecan immunoreactivity increased with age in the mouse visual cortex. We have pointed out that PNNs are localized on a subset of GABAergic interneurons. Here, we did double labeling experiments with antibodies for aggrecan and PV at PD70. Results indicate that most cortical PV-containing cells in the visual cortex possessed a surrounding aggrecan-positive PNNs, while a small fraction of cortical cells did not show any co-localization of these two chemical components (Fig. 5D–F). As seen in Fig. 5, many of the aggrecan-positive neurons are not pyramid-shaped. These results indicate that the majority of aggrecan-expressing cells are interneurons. Because aggrecan-reactive nets are strongly expressed in the postnatal visual cortex (Fig. 5A, B and D), we asked whether altering visual input would alter the expression of aggrecan. To evaluate this, mice were reared in darkness from birth to P28. The results showed that dark rearing reduced the expression of aggrecan in V1 at PD28 relative to that in normal animals at the same age. Quantitatively, the density of cells expressing aggrecan in layer 4 was affected by dark rearing, while no significant difference was observed in other layers (Fig. 5H). These results demonstrated that aggrecan expression is regulated by sensory input during postnatal development. Taken together, these data indicate that aggrecan, by aggregating in PNNs play an important role in restricting cortical plasticity. To further investigate the expression of other PNN components, we applied one goat polyclonal antibody for tenascin-R to examine the expression of tenascin-R at different postnatal ages in V1 in normal and dark-reared mice. The results showed that the overall and per layer quantities of tenascin-R-expressing neurons significantly increased from PD14 to PD70 (Fig. S2B, C and E). Tenascin-R first appeared around PD14 as no signal was detected in PD12 mice (Fig. S2A) and only a few weak signals were seen in PD14 mice (Fig. S2B). Different from the

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

357

Fig. 5. Experience-dependent development of aggrecan in mouse V1. A-D: Fluorescence staining of aggrecan (red) in cortical cells of the mouse visual cortex at postnatal days 14, 28, dark-28 and 70. Scale bar: 200 μm. E–F: Fluorescence staining of PV (green, E) and double-staining (merged color, F) in visual cortical cells at PD70. G–H: Developmental changes in the density (mean ± S.E.M.) of aggrecan-stained cells in the whole cortical area (G) and in individual layer (H) of the visual cortex during PD14-70 including dark-reared mice at PD28 (dark-PD28), compared to that in normal mice at PD28. *P b 0.05, **P b 0.01, ***P b 0.001; one-way ANOVA.

distribution of aggrecan, layer 4 possessed the least tenascin-Rexpressing cells relative to other layers around PD70. Anti-PV antibody was co-applied to see whether tenascin-R, like aggrecan also expresses mainly in PV-positive neurons. To our surprise, only a small fraction of cortical cells showed co-expression of these two proteins. Rearing the animals in complete darkness from birth to PD28 resulted in decreased expression of tenascin-R (Fig. S2C and D). Taken together, these results demonstrate that tenascin-R is increasingly expressed

during the postnatal development of mouse visual cortex in an experience dependent manner. 2.2. Experience-dependent Expression of two CSPG Receptors in Mouse V1 Although the appearance of PNNs has been widely reported in many areas of the central nervous system of various animal species, it remains less clear exactly about the molecular mechanism by

358

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

which PNNs regulate brain function. PNNs facilitate the transfer of Otx2, accelerating maturation of the PV-positive interneuron that is necessary and sufficient to open, then close, a critical period of plasticity in the developing mouse visual cortex (Sugiyama et al., 2008; Beurdeley et al., 2012). These results suggest a mechanism by which PNNs regulate cortical plasticity. PNNs may also function in other ways, especially considering that functional CSPG receptors have been indentified recently (Shen et al., 2009; Fisher et al., 2011; Dickendesher et al., 2012). Detailed examination of the expression profile of CSPG receptors can provide important knowledge on how PNNs regulate the development, maintenance and plasticity of neural circuits. To do this, we investigated the expressions of two CSPG receptors – NgR and LAR during the postnatal development of mouse visual cortex. We found that both of them were increasingly expressed during postnatal development from PD12 to PD70 and dark rearing led to decreased expression of them, suggesting that they play important roles in regulating the development, maintenance and plasticity of the cortex via mediating the function of PNNs. 2.2.1. Experience-dependent Development of NgR in Mouse V1 First, we examined the expression of Nogo receptor (NgR) in normal and dark-reared mice in V1 from PD12 to PD70 using anti-NgR antibody. WFA was co-applied to label PNNs. No obvious NgR staining was found in V1 in PD12 (n = 4; data not shown). We found that NgR was expressed at quite a low level by PD14 while increasingly expressed in PD28 and PD70 (Fig. 6A, B and D). NgR did not distribute evenly across cortical layers, expressing heavily in layer 2/3 and 5 while quite low in layer 4 in PD28 and PD70 (Fig. 6B and D). In layer 2/3 and layer 5, NgR is expressed by a large proportion of neurons in PD28 and PD70, which suggests that pyramidal neurons also express NgR. In support of this, a close examination of NgR-expressing cells shows that some of them are clearly pyramid-shaped. Meanwhile, a large proportion of PNN-enveloped cells expressed NgR and their density increased significantly during this period (Fig. 6B, D, E and F). These results suggest that PNNs function in both pyramidal neurons and GABAergic interneurons through CSPG receptors expressed by them. Furthermore, visual deprivation by dark-rearing from birth led to an obvious decline in the expression of NgR in PD28 mice, compared to that in normal mice at the same age (Fig. 6B, C, E and F). In summary, there is an activity-dependent expression of NgR in the development of mouse visual cortex. These results suggest that the NgR, by mediating the function of PNNs contribute to the development, maintenance and plasticity of the cortex. 2.2.2. Experience-dependent Development of LAR in Mouse V1 LAR is another functional CSPG receptor indentified recently (Fisher et al., 2011). Thus, we further examined the expression profile of LAR in normal and dark-reared mice in V1 from PD12 to PD70 using anti-LAR antibody. WFA was added to label PNNs. We found that LAR was expressed in a small number of cells by PD14 while increasingly expressed in PD28 and PD70 (Fig. 7A, B and D). Similar to the distribution of NgR, layer 5 had the maximum LAR-expressing cells out of all the layers in V1 in PD28 and PD70 (Fig. 7B and D). Meanwhile, a large proportion of PNN-enveloped cells express LAR and they increased significantly during this period (Fig. 7B, D, E and F). Furthermore, we found that visual deprivation by dark-rearing from birth led to an obvious decrease in the expression of LAR in PD28 mice, compared to that in normal mice at the same age (Fig. 7B, C, E and F). Together, these results suggest that LAR is involved in regulating the experience-dependent plasticity of the cortex. 3. Discussion In the present study, we demonstrate that in early development, PNNs detected by Wisteria floribunda agglutinin (WFA) in the visual cortex preferentially surround the PV-positive inhibitory interneurons

in cortical layers 2–6, and that the density of PNN-enveloped cortical neurons undergoes significant increases during 3–6 weeks after birth. In addition, PNNs detected with the specific antibodies against the two PNN component proteins aggrecan and tenascin-R showed a similar temporal profile. This PNN development process temporally correlates well with a decline in experience-dependent plasticity and the closure of the critical period. We then showed that PNN formation is dependent on appropriate sensory input as visual deprivation early in development results in reduced PNN formation in the visual cortex. These results demonstrate an experience-dependent maturation of PNNs in postnatal development and suggest that PNNs play an important role in developmental cortical plasticity. Furthermore, we demonstrated that the expression of the CSPG receptors — NgR and LAR, detected by their respective antibodies, shows significant increases during postnatal weeks 2–10 in the mouse visual cortex and can also be reduced by sensory deprivation from birth. To our knowledge, this is the first demonstration of activity-dependent expression of CSPG receptors in the visual cortex. In conclusion, postnatal construction of PNNs reaches the maturation around specific population of GABAergic inhibitory interneurons by the ending of the critical period of visual cortical plasticity. 3.1. Development of PNN in Mouse V1 and Experience-dependent Cortical Plasticity Consistent with previous studies of the rodent brain (Koppe et al., 1997a; Bruckner et al., 2000; Matthews et al., 2002), we found that PNNs detected by WFA or specific antibodies to aggrecan and Tenascin-R first appeared around P14, coincident with eye opening. In the developing rodent visual cortex, the effects of experience on cortical structure and function are weak or non-existent around eye opening (around PD12–13), peak around the fourth week of age, and then declines over several weeks. Thus, a postnatal period of 3–5 weeks in which the visual cortex shows high sensitivity to visual input changes is often termed as the critical period (Huang et al., 1999). In the present study, we found that PNNs underwent a quick formation in cortical layers 2–6 during a similar postnatal time-window: significantly increased formation of PNNs in V1 occurred during PD14-42 and reached a stabilized plateau during PD42-70. This progressively increasing development of PNNs temporally correlates well with a decline in experience-dependent plasticity and the closure of the critical period, which is in line with findings from studies done on the visual cortices of other mammals (Lander et al., 1997; Pizzorusso et al., 2002). This implies that the organization of PNNs in the visual cortex possibly influences timing of the critical period. In support of this, rearing animals in complete darkness from birth, which is known to prolong the critical period for ocular dominance plasticity, suppresses the developmental maturation of PNNs detected by WFA or specific antibodies to aggrecan and tenascin-R in the visual cortex. Of particular interest is the fact that, PNNs frequently enwrap parvalbumin-immunoreactive GABAergic interneurons in the cerebral cortex (Kosaka and Heizmann, 1989; Hartig et al., 1992; Bruckner et al., 1994; Hartig et al., 1994; Bruckner and Grosche, 2001; Pizzorusso et al., 2002; McRae et al., 2007). Here, we confirmed that PNNs highly colocalize with the calcium binding protein parvalbumin, a cytochemical marker for a major subtype of cortical GABAergic interneuron in the mouse visual cortex. Maturation of PV-positive large basket cells plays an important role in determining the progress of the critical period (Fagiolini et al., 2004; Hensch, 2005). It should be noted that throughout the postnatal development of the visual cortex, cortical layer 4 possessed the highest density of PV-containing and PV-enwrapped cells (Fig. 3G). Interestingly, PNNs around PV-positive interneuron by providing high affinity (orthodenticle homeobox 2) Otx2 homeoprotein binding cites are involved in the transfer of Otx2 into PV-positive interneurons, regulating the maturation of the PV-positive interneuron. This regulation is necessary and sufficient to open, then close, a critical

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

359

Fig. 6. Experience-dependent development of NgR in mouse V1. A–D: Fluorescence staining of NgR (green), WFA (red) and double-staining (merged color) in visual cortical cells at postnatal days 14, 28, dark-28 and 70. Representative cells expressing NgR and enwrapped by WFA-labeled PNNs in PD28 and PD70 are indicated by arrowheads (B and D). Scale bar: 100 μm. E–F: Developmental changes in the density (mean ± S.E.M.) of NgR-stained cells in the whole cortical area (E) and in individual layers (F) of the visual cortex during PD14-70 including dark-reared mice at PD28 (dark-PD28), compared to that in normal mice at PD28. *P b 0.05, **P b 0.01, ***P b 0.001; one-way ANOVA.

period of plasticity in the developing mouse visual cortex (Beurdeley et al., 2012). 3.2. Expression of Various PNN Components The main components of PNNs are chondroitin sulfate proteoglycans (CSPGs), hyaluronan (HA), link proteins and tenascin-R (Tn-R)

(Koppe et al., 1997b; Deepa et al., 2006; Carulli et al., 2007; Kwok et al., 2010). The major CSPGs include aggrecan, versican, neurocan, brevican, phosphacans, and NG2 (Matsui et al., 1998; Hagihara et al., 1999; Carulli et al., 2006). CSPGs are comprised of a single protein core and varying numbers of polysaccharide glycosaminoglycan (GAG) chains (Fisher et al., 2011; Wang and Fawcett, 2012). Aggrecan is present in all PNNs while neurocan, versican and phosphacan ⁄

360

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

Fig. 7. Experience-dependent development of LAR in mouse V1. A-D: Fluorescence staining of LAR (green), WFA (red) and double-staining (merged color) in visual cortical cells at postnatal days 14, 28, dark-28 and 70. Representative cells expressing LAR and enwrapped by WFA-labeled PNNs in PD28 and PD70 are indicated by arrowheads (B and D). Scale bar: 100 μm. E-F: Developmental changes in the density (mean ± S.E.M.) of LAR-stained cells in the whole cortical area (E) and in individual layers (F) of visual cortex during PD14-70 including dark-PD28 compared to normal PD28. *P b 0.05, **P b 0.01, ***P b 0.001; one-way ANOVA.

RPTPb are present in some but not all PNNs. The expression of link protein and aggrecan mRNA is up-regulated at the time of PNN formation during postnatal development, suggesting a role in triggering PNN formation (Galtrey et al., 2008). Our detailed study of the development of PNNs detected by WFA, and respective antibodies for aggrecan and tenascin-R revealed that all these components have a similar developmental profile. Experience-dependent expression of aggrecan provides

correlative evidence to support the hypothesis that aggrecan is the key CSPGs that regulates the termination of the critical period (Sur et al., 1988; Hockfield et al., 1990). In regard to the spatial distribution of these components, PNNs detected by the antibody to aggrecan and PNNs labeled with WFA both have the same pattern and mainly surround PV-postitive interneurons, while tenascin-R is mainly expressed in layer 5 and rarely co-localizes with PV.

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

3.3. Expression of CSPG Receptors — NgR and LAR in Developing Mouse Visual Cortex Besides indirectly acting on the maturation of the PV-positive interneuron network by facilitating the internalization of Otx2 (Sugiyama et al., 2008; Beurdeley et al., 2012), the identification of CSPG receptor opens a brand-new view on how PNNs might function in limiting synaptic plasticity, thus restricting the experience-dependent cortical plasticity in the developing brain (Shen et al., 2009; Fisher et al., 2011; Dickendesher et al., 2012). In the present study, we have investigated the expression of the two CSPGs receptors — NgR and LAR in postnatal development of the mouse V1. One interesting finding is that the spatial distribution of these two receptors is different from that of PNNs. PNNs detected by WFA or the antibody to aggrecan have the highest density in layer 4, the main recipient layer of thalamocortical input, while these two receptors are expressed densely in layer 2/3 and 5 but much lower in layer 4. Surprisingly, a majority of NgR-expressing cells in layer 4 are enveloped by PNN. In layer 2/3 and layer 5, NgR is expressed by a large proportion of neurons in PD28 and PD70, which suggest that pyramidal neurons also express NgR. In support of this, a close examination shows that some of the NgR-expressing cells are clearly pyramid-shaped. These results suggest that PNNs affect both pyramidal neurons and GABAergic interneurons through CSPG receptors expressed by these neurons. It is of great interest to know whether these signals onto excitatory and inhibitory neurons have distinct roles in regulating cortical plasticity. Further examinations on the temporal expression profile of these receptors showed that the expression of these receptors increased significantly from PD14 to PD70. Sensory deprivation from birth leads to reduced expression of these receptors. These results suggest that ECM through both CSPG receptors play an important role in regulating activity-driven cortical plasticity in the developing visual cortex. Further experiments on mice with overall or cell-type specific deletion of CSPG receptor(s) will help to test their functions. Our study on the expression of CSPG receptors in early development of the mouse visual cortex provides a basis for further research on whether these receptors play a role in regulating the critical period plasticity and whether they participate in regulating the maturation of PV-positive GABAergic interneurons. 3.4. Functional Implications of PNN Formation and CSPG Receptor Expression in the Developing Visual Cortex Enzymatic degradation of glycosaminoglycan (GAG) side chains of chondroitin sulfate proteoglycans (CSPGs) with Chondroitinase ABC (ChABC) disrupts the integrity of CSPG-rich PNN structures in adult rat V1. This consequently reactivates ocular dominance plasticity and enables structural and functional recovery from early monocular deprivation (Pizzorusso et al., 2002, 2006), suggesting that the construction of cortical PNNs act in controlling cortical plasticity at early postnatal developmental stages (Carulli et al., 2010; Kwok et al., 2011). Our finding of the stabilized formation of PNNs in the visual cortex around PD42 (the ending time of the V1 critical period) may provide a developmental basis for PNNs' potential involvement in regulating the ending of the critical period of the visual cortex. Moreover, it remains less explored exactly how PNNs regulate brain function. Interestingly, recent studies suggest that PNNs facilitate the transfer of Otx2, accelerating maturation of the PV-positive interneurons that are necessary and sufficient to open, then close, a critical period of plasticity in the developing mouse visual cortex (Sugiyama et al., 2008; Beurdeley et al., 2012). Of great importance, the identification of CSPG receptors provides another brand-new idea on how PNNs might function in limiting synaptic plasticity thus restricting the experience-dependent cortical plasticity in developing brain (Shen et al., 2009; Fisher et al., 2011; Dickendesher et al., 2012). The detailed examination of CSPG receptors provides new insights into how the ECM regulates neuronal structure and functions under

361

physiological conditions and following injury. We propose that CSPG receptors are part of a multicomponent molecular system that serves as a signaling platform for initiating pathways that regulate neuronal maturation and increase structural stability of synapses, thus regulating brain function. In summary, we showed that cortical PNNs are preferentially present in PV-positive inhibitory neurons in the mouse visual cortex, and that experience-dependent development of PNN formations and PV cell circuits takes place primarily within the critical period of experience-dependent cortical plasticity. We also demonstrated that the expression of the CSPG receptors – NgR and LAR – show significant experience-dependent increases during postnatal development in the mouse visual cortex. Given the important role played by cortical PNNs and PV-containing cell-mediated cortical inhibition in regulating the critical period of the visual cortex, these findings provide a developmental basis for understanding how these players regulate visual cortical plasticity during its development. 4. Experimental Procedures 4.1. Animals Experiments were performed on the primary visual cortex (V1) of C57BL/6J mice. The mice were divided into five groups according to age: PD10, PD14, PD28, PD42 and adult (≥PD70), with at least three mice in each group. Males and females were both used. Normal mice were raised under a 12-h light/dark cycle, while visually-deprived mice were reared in total darkness. All experimental procedures followed the protocols approved by the Animal Care and Use Committee of Institute of Neuroscience, Chinese Academy of Sciences (NA-100418). 4.2. Immunohistochemistry Mice were anaesthetized with 1% Nembutal and immediately perfused intracardially with saline (0.9% NaCl) followed by cold 4% paraformaldehyde (PFA) in 0.1 M phosphate buffer (pH 7.4). Brains were dissected and postfixed in the same fixative for 2 h at 4 °C, followed by equilibration in 30% sucrose in PBS for over 48 h. The 30 μm thick coronal sections were made in a cryostat and then stored at −20 °C. We used Wisteria floribunda agglutinin (WFA) (1:200, Vector), a lectin that recognizes most N-acetylgalactosamine residues present in perineuronal nets (Celio and Blumcke, 1994; Ajmo et al., 2008). We also use anti-aggrecan antibody (1:100, Millipore) to label aggrecanpositive PNNs. To stain for PV-containing GABAergic neurons, the rabbit polyclonal antibody against PV was used (1:500, Swant) (Ren et al., 1992; Gonchar et al., 2007). The anti-Nogo receptor (1:100, Millipore) and LAR antibody (1:100, Santa Cruz) were applied to mark two receptor for CSPGs. Sections were first washed three times (5 min for each) in 0.1 M phosphate-buffered saline (1× PBS, pH 7.4), then blocked in 10% normal goat serum (NGS) and 0.3% Triton X-100 in PBS for 1 hr, and finally incubated in the PBS solution containing primary antibodies overnight at 4 °C. After the three washes (5 min for each) in PBS, the sections were incubated in PBS containing secondary antibodies for 2 h at room temperature. After three 5-min washes in PBS, sections were incubated in DAPI staining solution for 10 min. After another round of three 5-min washings in PBS, the stained sections were mounted onto glass slides, air-dried and coverslipped with Mounting Medium (Vector). 4.3. Microscopy Imaging and Data Analysis All the fluorescence staining signals in brain sections were viewed and acquired by a Nikon A1 confocal microscope using a 10x objective and under the scanning mode of 1 × 3 jigsawed and 2 μm-step Z-stack. The data shown in the figures were measured and presented according to the cortical layer profiles – layer 2/3, layer 4, layer 5 and

362

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363

layer 6 – based on neuronal DAPI staining and the mouse cortical map. Each data point was measured from at least five coronal sections of an animal, and 3–6 animals were used for each postnatal age. All confocal images were acquired as a TIFF file, and analyzed with the ImageJ software (http://rsbweb.nih.gov/ij/). Data were presented as mean ± S.E.M., and the significance of statistical results was analyzed with the one-way ANOVA. Supplementary data to this article can be found online at http:// dx.doi.org/10.1016/j.matbio.2013.04.001. Acknowledgements We thank Dr. Xiaohui Zhang (Institute of Neuroscience) for providing experimental facilities, his advice in experiment design and help in manuscript preparation. We thank Dr. Qian Hu (Institute of Neuroscience) for his technical assistance in microscopy imaging. We are grateful to Prof. Zhongdong Qiao (Shanghai Jiao Tong University) for suggestions and discussions. This work was supported by a grant from the 973 Program (2011CBA00403). References Ajmo, J.M., Eakin, A.K., Hamel, M.G., Gottschall, P.E., 2008. Discordant localization of WFA reactivity and brevican/ADAMTS-derived fragment in rodent brain. BMC Neurosci. 9, 14. Asher, R.A., Morgenstern, D.A., Fidler, P.S., Adcock, K.H., Oohira, A., Braistead, J.E., Levine, J.M., Margolis, R.U., Rogers, J.H., Fawcett, J.W., 2000. Neurocan is upregulated in injured brain and in cytokine-treated astrocytes. J. Neurosci. 20, 2427–2438. Beurdeley, M., Spatazza, J., Lee, H.H., Sugiyama, S., Bernard, C., Di Nardo, A.A., Hensch, T.K., Prochiantz, A., 2012. Otx2 binding to perineuronal nets persistently regulates plasticity in the mature visual cortex. J. Neurosci. 32, 9429–9437. Bruckner, G., Grosche, J., 2001. Perineuronal nets show intrinsic patterns of extracellular matrix differentiation in organotypic slice cultures. Exp. Brain Res. 137, 83–93. Bruckner, G., Brauer, K., Hartig, W., Wolff, J.R., Rickmann, M.J., Derouiche, A., Delpech, B., Girard, N., Oertel, W.H., Reichenbach, A., 1993. Perineuronal nets provide a polyanionic, glia-associated form of microenvironment around certain neurons in many parts of the rat brain. Glia 8, 183–200. Bruckner, G., Seeger, G., Brauer, K., Hartig, W., Kacza, J., Bigl, V., 1994. Cortical areas are revealed by distribution patterns of proteoglycan components and parvalbumin in the Mongolian gerbil and rat. Brain Res. 658, 67–86. Bruckner, G., Grosche, J., Schmidt, S., Hartig, W., Margolis, R.U., Delpech, B., Seidenbecher, C.I., Czaniera, R., Schachner, M., 2000. Postnatal development of perineuronal nets in wild-type mice and in a mutant deficient in tenascin-R. J. Comp. Neurol. 428, 616–629. Carulli, D., Rhodes, K.E., Brown, D.J., Bonnert, T.P., Pollack, S.J., Oliver, K., Strata, P., Fawcett, J.W., 2006. Composition of perineuronal nets in the adult rat cerebellum and the cellular origin of their components. J. Comp. Neurol. 494, 559–577. Carulli, D., Rhodes, K.E., Fawcett, J.W., 2007. Upregulation of aggrecan, link protein 1, and hyaluronan synthases during formation of perineuronal nets in the rat cerebellum. J. Comp. Neurol. 501, 83–94. Carulli, D., Pizzorusso, T., Kwok, J.C., Putignano, E., Poli, A., Forostyak, S., Andrews, M.R., Deepa, S.S., Glant, T.T., Fawcett, J.W., 2010. Animals lacking link protein have attenuated perineuronal nets and persistent plasticity. Brain 133, 2331–2347. Celio, M.R., 1986. Parvalbumin in Most Gamma-Aminobutyric-Acid Containing Neurons of the Rat Cerebral-Cortex. Science 231, 995–997. Celio, M.R., Blumcke, I., 1994. Perineuronal nets—a specialized form of extracellular matrix in the adult nervous system. Brain Res. Brain Res. Rev. 19, 128–145. Deepa, S.S., Carulli, D., Galtrey, C., Rhodes, K., Fukuda, J., Mikami, T., Sugahara, K., Fawcett, J.W., 2006. Composition of perineuronal net extracellular matrix in rat brain: a different disaccharide composition for the net-associated proteoglycans. J. Biol. Chem. 281, 17789–17800. del Rio, J.A., de Lecea, L., Ferrer, I., Soriano, E., 1994. The development of parvalbuminimmunoreactivity in the neocortex of the mouse. Brain Res. Dev. Brain Res. 81, 247–259. Dickendesher, T.L., Baldwin, K.T., Mironova, Y.A., Koriyama, Y., Raiker, S.J., Askew, K.L., Wood, A., Geoffroy, C.G., Zheng, B., Liepmann, C.D., Katagiri, Y., Benowitz, L.I., Geller, H.M., Giger, R.J., 2012. NgR1 and NgR3 are receptors for chondroitin sulfate proteoglycans. Nat. Neurosci. 15, 703–712. Espinosa, J.S., Stryker, M.P., 2012. Development and plasticity of the primary visual cortex. Neuron 75, 230–249. Fagiolini, M., Fritschy, J.M., Low, K., Mohler, H., Rudolph, U., Hensch, T.K., 2004. Specific GABAA circuits for visual cortical plasticity. Science 303, 1681–1683. Fisher, D., Xing, B., Dill, J., Li, H., Hoang, H.H., Zhao, Z., Yang, X.L., Bachoo, R., Cannon, S., Longo, F.M., Sheng, M., Silver, J., Li, S., 2011. Leukocyte common antigen-related phosphatase is a functional receptor for chondroitin sulfate proteoglycan axon growth inhibitors. J. Neurosci. 31, 14051–14066. Fitch, M.T., Silver, J., 1997. Glial cell extracellular matrix: boundaries for axon growth in development and regeneration. Cell Tissue Res. 290, 379–384.

Foscarin, S., Ponchione, D., Pajaj, E., Leto, K., Gawlak, M., Wilczynski, G.M., Rossi, F., Carulli, D., 2011. Experience-dependent plasticity and modulation of growth regulatory molecules at central synapses. PLoS One 6, e16666. Galtrey, C.M., Kwok, J.C., Carulli, D., Rhodes, K.E., Fawcett, J.W., 2008. Distribution and synthesis of extracellular matrix proteoglycans, hyaluronan, link proteins and tenascin-R in the rat spinal cord. Eur. J. Neurosci. 27, 1373–1390. Gonchar, Y., Wang, Q., Burkhalter, A., 2007. Multiple distinct subtypes of GABAergic neurons in mouse visual cortex identified by triple immunostaining. Front. Neuroanat. 1, 3. Gordon, J.A., Stryker, M.P., 1996. Experience-dependent plasticity of binocular responses in the primary visual cortex of the mouse. J. Neurosci. 16, 3274–3286. Grumet, M., Friedlander, D.R., Sakurai, T., 1996. Functions of brain chondroitin sulfate proteoglycans during developments: interactions with adhesion molecules. Perspect. Dev. Neurobiol. 3, 319–330. Guimaraes, A., Zaremba, S., Hockfield, S., 1990. Molecular and morphological changes in the cat lateral geniculate nucleus and visual cortex induced by visual deprivation are revealed by monoclonal antibodies Cat-304 and Cat-301. J. Neurosci. 10, 3014–3024. Hagihara, K., Miura, R., Kosaki, R., Berglund, E., Ranscht, B., Yamaguchi, Y., 1999. 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. Hartig, W., Brauer, K., Bruckner, G., 1992. Wisteria floribunda agglutinin-labelled nets surround parvalbumin-containing neurons. Neuroreport 3, 869–872. Hartig, W., Brauer, K., Bigl, V., Bruckner, G., 1994. Chondroitin sulfate proteoglycanimmunoreactivity of lectin-labeled perineuronal nets around parvalbumincontaining neurons. Brain Res. 635, 307–311. Hensch, T.K., 2005. Critical period plasticity in local cortical circuits. Nat. Rev. Neurosci. 6, 877–888. Hockfield, S., Kalb, R.G., Zaremba, S., Fryer, H., 1990. Expression of neural proteoglycans correlates with the acquisition of mature neuronal properties in the mammalian brain. Cold Spring Harb. Symp. Quant. Biol. 55, 505–514. Huang, Z.J., Kirkwood, A., Pizzorusso, T., Porciatti, V., Morales, B., Bear, M.F., Maffei, L., Tonegawa, S., 1999. BDNF regulates the maturation of inhibition and the critical period of plasticity in mouse visual cortex. Cell 98, 739–755. Kind, P.C., Beaver, C.J., Mitchell, D.E., 1995. Effects of early periods of monocular deprivation and reverse lid suture on the development of Cat-301 immunoreactivity in the dorsal lateral geniculate nucleus (dLGN) of the cat. J. Comp. Neurol. 359, 523–536. Kind, P.C., Sengpiel, F., Beaver, C.J., Crocker-Buque, A., Kelly, G.M., Matthews, R.T., Mitchell, D.E., 2013. The development and activity-dependent expression of aggrecan in the cat visual cortex. Cereb. Cortex 23, 349–360. Klein, R., 2004. Eph/ephrin signaling in morphogenesis, neural development and plasticity. Curr. Opin. Cell Biol. 16, 580–589. Koppe, G., Bruckner, G., Brauer, K., Hartig, W., Bigl, V., 1997a. Developmental patterns of proteoglycan-containing extracellular matrix in perineuronal nets and neuropil of the postnatal rat brain. Cell Tissue Res. 288, 33–41. Koppe, G., Bruckner, G., Hartig, W., Delpech, B., Bigl, V., 1997b. Characterization of proteoglycan-containing perineuronal nets by enzymatic treatments of rat brain sections. Histochem. J. 29, 11–20. Kosaka, T., Heizmann, C.W., 1989. Selective staining of a population of parvalbumincontaining GABAergic neurons in the rat cerebral cortex by lectins with specific affinity for terminal N-acetylgalactosamine. Brain Res. 483, 158–163. Kwok, J.C., Carulli, D., Fawcett, J.W., 2010. In vitro modeling of perineuronal nets: hyaluronan synthase and link protein are necessary for their formation and integrity. J. Neurochem. 114, 1447–1459. Kwok, J.C., Dick, G., Wang, D., Fawcett, J.W., 2011. Extracellular matrix and perineuronal nets in CNS repair. Dev. Neurobiol. 71, 1073–1089. Lander, C., Kind, P., Maleski, M., Hockfield, S., 1997. A family of activity-dependent neuronal cell-surface chondroitin sulfate proteoglycans in cat visual cortex. J. Neurosci. 17, 1928–1939. Liu, B.P., Cafferty, W.B., Budel, S.O., Strittmatter, S.M., 2006. Extracellular regulators of axonal growth in the adult central nervous system. Philos. Trans. R. Soc. Lond. B Biol. Sci. 361, 1593–1610. Matsui, F., Nishizuka, M., Yasuda, Y., Aono, S., Watanabe, E., Oohira, A., 1998. Occurrence of a N-terminal proteolytic fragment of neurocan, not a C-terminal half, in a perineuronal net in the adult rat cerebrum. Brain Res. 790, 45–51. Matthews, R.T., Kelly, G.M., Zerillo, C.A., Gray, G., Tiemeyer, M., Hockfield, S., 2002. Aggrecan glycoforms contribute to the molecular heterogeneity of perineuronal nets. J. Neurosci. 22, 7536–7547. McKeon, R.J., Jurynec, M.J., Buck, C.R., 1999. The chondroitin sulfate proteoglycans neurocan and phosphacan are expressed by reactive astrocytes in the chronic CNS glial scar. J. Neurosci. 19, 10778–10788. McRae, P.A., Rocco, M.M., Kelly, G., Brumberg, J.C., Matthews, R.T., 2007. Sensory deprivation alters aggrecan and perineuronal net expression in the mouse barrel cortex. J. Neurosci. 27, 5405–5413. Mukhopadhyay, A., McGuire, T., Peng, C.Y., Kessler, J.A., 2009. Differential effects of BMP signaling on parvalbumin and somatostatin interneuron differentiation. Development 136, 2633–2642. Niederost, B.P., Zimmermann, D.R., Schwab, M.E., Bandtlow, C.E., 1999. Bovine CNS myelin contains neurite growth-inhibitory activity associated with chondroitin sulfate proteoglycans. J. Neurosci. 19, 8979–8989. Oohira, A., Matsui, F., Katoh-Semba, R., 1991. Inhibitory effects of brain chondroitin sulfate proteoglycans on neurite outgrowth from PC12D cells. J. Neurosci. 11, 822–827. Pizzorusso, T., Medini, P., Berardi, N., Chierzi, S., Fawcett, J.W., Maffei, L., 2002. Reactivation of ocular dominance plasticity in the adult visual cortex. Science 298, 1248–1251.

Q. Ye, Q. Miao / Matrix Biology 32 (2013) 352–363 Pizzorusso, T., Medini, P., Landi, S., Baldini, S., Berardi, N., Maffei, L., 2006. Structural and functional recovery from early monocular deprivation in adult rats. Proc. Natl. Acad. Sci. U. S. A. 103, 8517–8522. Ren, J.Q., Aika, Y., Heizmann, C.W., Kosaka, T., 1992. Quantitative analysis of neurons and glial cells in the rat somatosensory cortex, with special reference to GABAergic neurons and parvalbumin-containing neurons. Exp. Brain Res. 92, 1–14. Schweizer, M., Streit, W.J., Muller, C.M., 1993. Postnatal development and localization of an N-acetylgalactosamine containing glycoconjugate associated with nonpyramidal neurons in cat visual cortex. J. Comp. Neurol. 329, 313–327. Shen, Y., Tenney, A.P., Busch, S.A., Horn, K.P., Cuascut, F.X., Liu, K., He, Z., Silver, J., Flanagan, J.G., 2009. PTPsigma is a receptor for chondroitin sulfate proteoglycan, an inhibitor of neural regeneration. Science 326, 592–596. Snow, D.M., Brown, E.M., Letourneau, P.C., 1996. Growth cone behavior in the presence of soluble chondroitin sulfate proteoglycan (CSPG), compared to behavior on CSPG bound to laminin or fibronectin. Int. J. Dev. Neurosci. 14, 331–349.

363

Sugiyama, S., Di Nardo, A.A., Aizawa, S., Matsuo, I., Volovitch, M., Prochiantz, A., Hensch, T.K., 2008. Experience-dependent transfer of Otx2 homeoprotein into the visual cortex activates postnatal plasticity. Cell 134, 508–520. Sur, M., Frost, D.O., Hockfield, S., 1988. Expression of a surface-associated antigen on Y-cells in the cat lateral geniculate nucleus is regulated by visual experience. J. Neurosci. 8, 874–882. Wang, D., Fawcett, J., 2012. The perineuronal net and the control of CNS plasticity. Cell Tissue Res. 349, 147–160. Zaremba, S., Guimaraes, A., Kalb, R.G., Hockfield, S., 1989. Characterization of an activity-dependent, neuronal surface proteoglycan identified with monoclonal antibody Cat-301. Neuron 2, 1207–1219.