Limits...
Cell surface heparan sulfate proteoglycan syndecan-2 induces the maturation of dendritic spines in rat hippocampal neurons.

Ethell IM, Yamaguchi Y - J. Cell Biol. (1999)

Bottom Line: We demonstrate that the cell surface heparan sulfate proteoglycan syndecan-2 plays a critical role in spine development.Deletion of the COOH-terminal EFYA motif of syndecan-2, the binding site for PDZ domain proteins, abrogates the spine-promoting activity of syndecan-2.Our results indicate that syndecan-2 plays a direct role in the development of postsynaptic specialization through its interactions with PDZ domain proteins.

View Article: PubMed Central - PubMed

Affiliation: The Burnham Institute, La Jolla, California 92037, USA.

ABSTRACT
Dendritic spines are small protrusions that receive synapses, and changes in spine morphology are thought to be the structural basis for learning and memory. We demonstrate that the cell surface heparan sulfate proteoglycan syndecan-2 plays a critical role in spine development. Syndecan-2 is concentrated at the synapses, specifically on the dendritic spines of cultured hippocampal neurons, and its accumulation occurs concomitant with the morphological maturation of spines from long thin protrusions to stubby and headed shapes. Early introduction of syndecan-2 cDNA into immature hippocampal neurons, by transient transfection, accelerates spine formation from dendritic protrusions. Deletion of the COOH-terminal EFYA motif of syndecan-2, the binding site for PDZ domain proteins, abrogates the spine-promoting activity of syndecan-2. Syndecan-2 clustering on dendritic protrusions does not require the PDZ domain-binding motif, but another portion of the cytoplasmic domain which includes a protein kinase C phosphorylation site. Our results indicate that syndecan-2 plays a direct role in the development of postsynaptic specialization through its interactions with PDZ domain proteins.

Show MeSH

Related in: MedlinePlus

Forced expression  of syndecan-2 in young hippocampal neurons induces  the morphological maturation of dendritic spines. Hippocampal neurons at 1 DIV  were cotransfected in 1:1 ratio with full-length syndecan-2 plus GFP (A) or with  the syndecan-2 ΔEFYA deletion mutant plus GFP (B).  Cells were analyzed 7 d after  transfection by confocal microscopy after immunostaining with anti–syndecan-2 antibodies which recognize the  extracellular domain of syndecan-2 (red). Those neurons  that showed only GFP fluorescence, but were negative  for syndecan-2, were considered as control transfected  neurons (C). Note that the  protrusions on neurons transfected with full-length syndecan-2 (A) are short and  exhibit a mature spine morphology. Transfected syndecan-2 is expressed on these  spines. Arrowheads indicate  stubby and mushroom-shaped  spines. In contrast, syndecan-2 ΔEFYA-transfected  neurons (B) do not have spines with mature morphology. Most of the protrusions are long and filopodia-like (arrows), as seen in control transfected neurons (C). Note: although there is no effect on the morphology of protrusions,  syndecan-2 ΔEFYA is targeted to these protrusions and forms clusters (B), as  seen in neurons transfected with full-length syndecan-2 (A). (D) Nontransfected cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic  protrusions are long, thin filopodia, as seen in transfected control (C). (E)  4-wk-old nontransfected cultured hippocampal neurons. By 4 wk in culture  dendritic protrusions are transformed into short spines with stubby or mushroom-like shapes. Note: in D and E dendritic protrusions are visualized by  DiO fluorescence. Bars, 5 μm. (F–J) Statistical analysis of dendritic protrusion  length in transfected hippocampal neurons. Protrusions in neurons transfected  with full-length syndecan-2 (F) are shorter and exhibit more homogeneous distribution than control transfected neurons. Control transfected neurons (H)  exhibit high variability in protrusion length, and the majority of the protrusions are longer than 1 μm, as also shown for untransfected control (I) at  the same stage in culture (8 DIV). Neurons transfected with the syndecan-2  ΔEFYA deletion mutant (G) show high variability in protrusion length similar  to that of control transfected neurons. There is no significant difference of  dendritic protrusion length of control and syndecan-2 ΔEFYA transfected  neurons. Decrease in dendritic protrusion length in syndecan-2 transfected  neurons at 1 wk in vitro was similar to changes in dendritic protrusion length in  4-wk-nontransfected cultures (J).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2132915&req=5

Figure 6: Forced expression of syndecan-2 in young hippocampal neurons induces the morphological maturation of dendritic spines. Hippocampal neurons at 1 DIV were cotransfected in 1:1 ratio with full-length syndecan-2 plus GFP (A) or with the syndecan-2 ΔEFYA deletion mutant plus GFP (B). Cells were analyzed 7 d after transfection by confocal microscopy after immunostaining with anti–syndecan-2 antibodies which recognize the extracellular domain of syndecan-2 (red). Those neurons that showed only GFP fluorescence, but were negative for syndecan-2, were considered as control transfected neurons (C). Note that the protrusions on neurons transfected with full-length syndecan-2 (A) are short and exhibit a mature spine morphology. Transfected syndecan-2 is expressed on these spines. Arrowheads indicate stubby and mushroom-shaped spines. In contrast, syndecan-2 ΔEFYA-transfected neurons (B) do not have spines with mature morphology. Most of the protrusions are long and filopodia-like (arrows), as seen in control transfected neurons (C). Note: although there is no effect on the morphology of protrusions, syndecan-2 ΔEFYA is targeted to these protrusions and forms clusters (B), as seen in neurons transfected with full-length syndecan-2 (A). (D) Nontransfected cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic protrusions are long, thin filopodia, as seen in transfected control (C). (E) 4-wk-old nontransfected cultured hippocampal neurons. By 4 wk in culture dendritic protrusions are transformed into short spines with stubby or mushroom-like shapes. Note: in D and E dendritic protrusions are visualized by DiO fluorescence. Bars, 5 μm. (F–J) Statistical analysis of dendritic protrusion length in transfected hippocampal neurons. Protrusions in neurons transfected with full-length syndecan-2 (F) are shorter and exhibit more homogeneous distribution than control transfected neurons. Control transfected neurons (H) exhibit high variability in protrusion length, and the majority of the protrusions are longer than 1 μm, as also shown for untransfected control (I) at the same stage in culture (8 DIV). Neurons transfected with the syndecan-2 ΔEFYA deletion mutant (G) show high variability in protrusion length similar to that of control transfected neurons. There is no significant difference of dendritic protrusion length of control and syndecan-2 ΔEFYA transfected neurons. Decrease in dendritic protrusion length in syndecan-2 transfected neurons at 1 wk in vitro was similar to changes in dendritic protrusion length in 4-wk-nontransfected cultures (J).

Mentions: The highly specific localization of syndecan-2 on dendritic spines and the timing of its appearance suggest that syndecan-2 may be functionally involved in the development and maturation of dendritic spines. It has been shown that mature dendritic spines develop from thin, filopodia-like protrusions, and that this process is induced by the formation of contacts between the dendritic protrusions and nearby axons (Ziv and Smith, 1996). In cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic protrusions are characterized as long, thin filopodia-like structures (Fig. 6 D; also see Papa et al., 1995; Ziv and Smith, 1996). During the next 2 wk, these filopodia-like protrusions actively initiate contacts with nearby axons, and by 3–4 wk in vitro, transform into mature spines with stubby or mushroom-like shapes (Fig. 6 E), as seen with hippocampal dendritic spines in vivo (Papa et al., 1995).


Cell surface heparan sulfate proteoglycan syndecan-2 induces the maturation of dendritic spines in rat hippocampal neurons.

Ethell IM, Yamaguchi Y - J. Cell Biol. (1999)

Forced expression  of syndecan-2 in young hippocampal neurons induces  the morphological maturation of dendritic spines. Hippocampal neurons at 1 DIV  were cotransfected in 1:1 ratio with full-length syndecan-2 plus GFP (A) or with  the syndecan-2 ΔEFYA deletion mutant plus GFP (B).  Cells were analyzed 7 d after  transfection by confocal microscopy after immunostaining with anti–syndecan-2 antibodies which recognize the  extracellular domain of syndecan-2 (red). Those neurons  that showed only GFP fluorescence, but were negative  for syndecan-2, were considered as control transfected  neurons (C). Note that the  protrusions on neurons transfected with full-length syndecan-2 (A) are short and  exhibit a mature spine morphology. Transfected syndecan-2 is expressed on these  spines. Arrowheads indicate  stubby and mushroom-shaped  spines. In contrast, syndecan-2 ΔEFYA-transfected  neurons (B) do not have spines with mature morphology. Most of the protrusions are long and filopodia-like (arrows), as seen in control transfected neurons (C). Note: although there is no effect on the morphology of protrusions,  syndecan-2 ΔEFYA is targeted to these protrusions and forms clusters (B), as  seen in neurons transfected with full-length syndecan-2 (A). (D) Nontransfected cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic  protrusions are long, thin filopodia, as seen in transfected control (C). (E)  4-wk-old nontransfected cultured hippocampal neurons. By 4 wk in culture  dendritic protrusions are transformed into short spines with stubby or mushroom-like shapes. Note: in D and E dendritic protrusions are visualized by  DiO fluorescence. Bars, 5 μm. (F–J) Statistical analysis of dendritic protrusion  length in transfected hippocampal neurons. Protrusions in neurons transfected  with full-length syndecan-2 (F) are shorter and exhibit more homogeneous distribution than control transfected neurons. Control transfected neurons (H)  exhibit high variability in protrusion length, and the majority of the protrusions are longer than 1 μm, as also shown for untransfected control (I) at  the same stage in culture (8 DIV). Neurons transfected with the syndecan-2  ΔEFYA deletion mutant (G) show high variability in protrusion length similar  to that of control transfected neurons. There is no significant difference of  dendritic protrusion length of control and syndecan-2 ΔEFYA transfected  neurons. Decrease in dendritic protrusion length in syndecan-2 transfected  neurons at 1 wk in vitro was similar to changes in dendritic protrusion length in  4-wk-nontransfected cultures (J).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132915&req=5

Figure 6: Forced expression of syndecan-2 in young hippocampal neurons induces the morphological maturation of dendritic spines. Hippocampal neurons at 1 DIV were cotransfected in 1:1 ratio with full-length syndecan-2 plus GFP (A) or with the syndecan-2 ΔEFYA deletion mutant plus GFP (B). Cells were analyzed 7 d after transfection by confocal microscopy after immunostaining with anti–syndecan-2 antibodies which recognize the extracellular domain of syndecan-2 (red). Those neurons that showed only GFP fluorescence, but were negative for syndecan-2, were considered as control transfected neurons (C). Note that the protrusions on neurons transfected with full-length syndecan-2 (A) are short and exhibit a mature spine morphology. Transfected syndecan-2 is expressed on these spines. Arrowheads indicate stubby and mushroom-shaped spines. In contrast, syndecan-2 ΔEFYA-transfected neurons (B) do not have spines with mature morphology. Most of the protrusions are long and filopodia-like (arrows), as seen in control transfected neurons (C). Note: although there is no effect on the morphology of protrusions, syndecan-2 ΔEFYA is targeted to these protrusions and forms clusters (B), as seen in neurons transfected with full-length syndecan-2 (A). (D) Nontransfected cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic protrusions are long, thin filopodia, as seen in transfected control (C). (E) 4-wk-old nontransfected cultured hippocampal neurons. By 4 wk in culture dendritic protrusions are transformed into short spines with stubby or mushroom-like shapes. Note: in D and E dendritic protrusions are visualized by DiO fluorescence. Bars, 5 μm. (F–J) Statistical analysis of dendritic protrusion length in transfected hippocampal neurons. Protrusions in neurons transfected with full-length syndecan-2 (F) are shorter and exhibit more homogeneous distribution than control transfected neurons. Control transfected neurons (H) exhibit high variability in protrusion length, and the majority of the protrusions are longer than 1 μm, as also shown for untransfected control (I) at the same stage in culture (8 DIV). Neurons transfected with the syndecan-2 ΔEFYA deletion mutant (G) show high variability in protrusion length similar to that of control transfected neurons. There is no significant difference of dendritic protrusion length of control and syndecan-2 ΔEFYA transfected neurons. Decrease in dendritic protrusion length in syndecan-2 transfected neurons at 1 wk in vitro was similar to changes in dendritic protrusion length in 4-wk-nontransfected cultures (J).
Mentions: The highly specific localization of syndecan-2 on dendritic spines and the timing of its appearance suggest that syndecan-2 may be functionally involved in the development and maturation of dendritic spines. It has been shown that mature dendritic spines develop from thin, filopodia-like protrusions, and that this process is induced by the formation of contacts between the dendritic protrusions and nearby axons (Ziv and Smith, 1996). In cultured hippocampal neurons at 1 wk in vitro, the majority of dendritic protrusions are characterized as long, thin filopodia-like structures (Fig. 6 D; also see Papa et al., 1995; Ziv and Smith, 1996). During the next 2 wk, these filopodia-like protrusions actively initiate contacts with nearby axons, and by 3–4 wk in vitro, transform into mature spines with stubby or mushroom-like shapes (Fig. 6 E), as seen with hippocampal dendritic spines in vivo (Papa et al., 1995).

Bottom Line: We demonstrate that the cell surface heparan sulfate proteoglycan syndecan-2 plays a critical role in spine development.Deletion of the COOH-terminal EFYA motif of syndecan-2, the binding site for PDZ domain proteins, abrogates the spine-promoting activity of syndecan-2.Our results indicate that syndecan-2 plays a direct role in the development of postsynaptic specialization through its interactions with PDZ domain proteins.

View Article: PubMed Central - PubMed

Affiliation: The Burnham Institute, La Jolla, California 92037, USA.

ABSTRACT
Dendritic spines are small protrusions that receive synapses, and changes in spine morphology are thought to be the structural basis for learning and memory. We demonstrate that the cell surface heparan sulfate proteoglycan syndecan-2 plays a critical role in spine development. Syndecan-2 is concentrated at the synapses, specifically on the dendritic spines of cultured hippocampal neurons, and its accumulation occurs concomitant with the morphological maturation of spines from long thin protrusions to stubby and headed shapes. Early introduction of syndecan-2 cDNA into immature hippocampal neurons, by transient transfection, accelerates spine formation from dendritic protrusions. Deletion of the COOH-terminal EFYA motif of syndecan-2, the binding site for PDZ domain proteins, abrogates the spine-promoting activity of syndecan-2. Syndecan-2 clustering on dendritic protrusions does not require the PDZ domain-binding motif, but another portion of the cytoplasmic domain which includes a protein kinase C phosphorylation site. Our results indicate that syndecan-2 plays a direct role in the development of postsynaptic specialization through its interactions with PDZ domain proteins.

Show MeSH
Related in: MedlinePlus