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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.

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Time-dependent expression of different HSPGs in cultured hippocampal neurons. (A and B) RT-PCR analysis was  performed with total RNA isolated from hippocampal neurons at  indicated days in vitro. The amounts of total RNA were standardized by the expression level of glyceraldehyde 3-phosphate  dehydrogenase (GAPDH). (A) RT-PCR analysis of syndecan-1,  glypican-1, and glypican-3. (B) RT-PCR analysis of syndecan-2  and syndecan-4. Expression of syndecan-2 and syndecan-4 increases during the course of the culture. (C–F) Immunostaining  of hippocampal neurons at 1 (C), 2 (D), 3 (E), and 4 (F) wk in  culture with anti–syndecan-2 antibodies. Syndecan-2 immunoreactivity was first detected at 2 wk and then became stronger at 3  (E) and 4 (F) wk in vitro. Note that syndecan-2 was expressed in  neurons in a time course and a pattern similar to that of the heparan sulfate immunostaining. Bar, 20 μm.
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Figure 4: Time-dependent expression of different HSPGs in cultured hippocampal neurons. (A and B) RT-PCR analysis was performed with total RNA isolated from hippocampal neurons at indicated days in vitro. The amounts of total RNA were standardized by the expression level of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). (A) RT-PCR analysis of syndecan-1, glypican-1, and glypican-3. (B) RT-PCR analysis of syndecan-2 and syndecan-4. Expression of syndecan-2 and syndecan-4 increases during the course of the culture. (C–F) Immunostaining of hippocampal neurons at 1 (C), 2 (D), 3 (E), and 4 (F) wk in culture with anti–syndecan-2 antibodies. Syndecan-2 immunoreactivity was first detected at 2 wk and then became stronger at 3 (E) and 4 (F) wk in vitro. Note that syndecan-2 was expressed in neurons in a time course and a pattern similar to that of the heparan sulfate immunostaining. Bar, 20 μm.

Mentions: To identify the molecular species of HSPGs expressed in the dendritic spines, we performed RT-PCR analysis. Pairs of specific oligonucleotides were designed for eight different HSPGs known to be expressed in nervous tissues. Among the HSPGs examined, no expression of perlecan, agrin, or syndecan-3 was detected at any stage of culture (not shown). Syndecan-1, glypican-1, and glypican-2 (cerebroglycan) were detected in young cultures, but their expression decreased substantially as the neurons matured (Fig. 4 A). Only syndecan-2 and syndecan-4 showed temporal expression patterns consistent with the immunostaining results (Fig. 4 B). No syndecan-2 mRNA was detected at any time between plating and 8 DIV. Expression of syndecan-2 was first detectable at 9 DIV and then steadily increased to reach a plateau at 21 DIV, while syndecan-4 expression increased more abruptly at 30 DIV.


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)

Time-dependent expression of different HSPGs in cultured hippocampal neurons. (A and B) RT-PCR analysis was  performed with total RNA isolated from hippocampal neurons at  indicated days in vitro. The amounts of total RNA were standardized by the expression level of glyceraldehyde 3-phosphate  dehydrogenase (GAPDH). (A) RT-PCR analysis of syndecan-1,  glypican-1, and glypican-3. (B) RT-PCR analysis of syndecan-2  and syndecan-4. Expression of syndecan-2 and syndecan-4 increases during the course of the culture. (C–F) Immunostaining  of hippocampal neurons at 1 (C), 2 (D), 3 (E), and 4 (F) wk in  culture with anti–syndecan-2 antibodies. Syndecan-2 immunoreactivity was first detected at 2 wk and then became stronger at 3  (E) and 4 (F) wk in vitro. Note that syndecan-2 was expressed in  neurons in a time course and a pattern similar to that of the heparan sulfate immunostaining. Bar, 20 μm.
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Related In: Results  -  Collection

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Figure 4: Time-dependent expression of different HSPGs in cultured hippocampal neurons. (A and B) RT-PCR analysis was performed with total RNA isolated from hippocampal neurons at indicated days in vitro. The amounts of total RNA were standardized by the expression level of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). (A) RT-PCR analysis of syndecan-1, glypican-1, and glypican-3. (B) RT-PCR analysis of syndecan-2 and syndecan-4. Expression of syndecan-2 and syndecan-4 increases during the course of the culture. (C–F) Immunostaining of hippocampal neurons at 1 (C), 2 (D), 3 (E), and 4 (F) wk in culture with anti–syndecan-2 antibodies. Syndecan-2 immunoreactivity was first detected at 2 wk and then became stronger at 3 (E) and 4 (F) wk in vitro. Note that syndecan-2 was expressed in neurons in a time course and a pattern similar to that of the heparan sulfate immunostaining. Bar, 20 μm.
Mentions: To identify the molecular species of HSPGs expressed in the dendritic spines, we performed RT-PCR analysis. Pairs of specific oligonucleotides were designed for eight different HSPGs known to be expressed in nervous tissues. Among the HSPGs examined, no expression of perlecan, agrin, or syndecan-3 was detected at any stage of culture (not shown). Syndecan-1, glypican-1, and glypican-2 (cerebroglycan) were detected in young cultures, but their expression decreased substantially as the neurons matured (Fig. 4 A). Only syndecan-2 and syndecan-4 showed temporal expression patterns consistent with the immunostaining results (Fig. 4 B). No syndecan-2 mRNA was detected at any time between plating and 8 DIV. Expression of syndecan-2 was first detectable at 9 DIV and then steadily increased to reach a plateau at 21 DIV, while syndecan-4 expression increased more abruptly at 30 DIV.

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