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Cadherin activity is required for activity-induced spine remodeling.

Okamura K, Tanaka H, Yagita Y, Saeki Y, Taguchi A, Hiraoka Y, Zeng LH, Colman DR, Miki N - J. Cell Biol. (2004)

Bottom Line: N-cadherin-venus fusion protein laterally dispersed along the expanding spine head.Overexpression of dominant-negative forms of N-cadherin resulted in the abrogation of the spine expansion.Inhibition of actin polymerization with cytochalasin D abolished the spine expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Osaka University Medical School, Suita, Japan.

ABSTRACT
Neural activity induces the remodeling of pre- and postsynaptic membranes, which maintain their apposition through cell adhesion molecules. Among them, N-cadherin is redistributed, undergoes activity-dependent conformational changes, and is required for synaptic plasticity. Here, we show that depolarization induces the enlargement of the width of spine head, and that cadherin activity is essential for this synaptic rearrangement. Dendritic spines visualized with green fluorescent protein in hippocampal neurons showed an expansion by the activation of AMPA receptor, so that the synaptic apposition zone may be expanded. N-cadherin-venus fusion protein laterally dispersed along the expanding spine head. Overexpression of dominant-negative forms of N-cadherin resulted in the abrogation of the spine expansion. Inhibition of actin polymerization with cytochalasin D abolished the spine expansion. Together, our data suggest that cadherin-based adhesion machinery coupled with the actin-cytoskeleton is critical for the remodeling of synaptic apposition zone.

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Evaluation of spine broadening by confocal microscopy. Z-series profiles of GFP-filled spine were collected at 0.2-μm focus intervals by using a confocal microscope at resting state and 30 min after stimulation (high K+ for 2 min). (A) Z-stack image represents enlargement of the lateral diameter of spine. (B) Z-stack image was thresholded at half maximal fluorescence intensity. An axis was laid as to run across the widest point of spine head (gray line). (C) The spine width measured at the widest point before and 30 min after depolarization is plotted. *P < 0.00002. (D) The single optical section that passes through the maximum spine diameter among z-series images. Note that the maximal optical section showed clear cotyloid shape with similar lateral size to the z-stack image. (E) The spine width measured on the maximal optical section before and 30 min after depolarization is plotted. **P < 0.000003. The measurements of 38 spines of four neurons (dendrites) were collected from four independent experiments (C and E). Bar, 1.25 μm.
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fig2: Evaluation of spine broadening by confocal microscopy. Z-series profiles of GFP-filled spine were collected at 0.2-μm focus intervals by using a confocal microscope at resting state and 30 min after stimulation (high K+ for 2 min). (A) Z-stack image represents enlargement of the lateral diameter of spine. (B) Z-stack image was thresholded at half maximal fluorescence intensity. An axis was laid as to run across the widest point of spine head (gray line). (C) The spine width measured at the widest point before and 30 min after depolarization is plotted. *P < 0.00002. (D) The single optical section that passes through the maximum spine diameter among z-series images. Note that the maximal optical section showed clear cotyloid shape with similar lateral size to the z-stack image. (E) The spine width measured on the maximal optical section before and 30 min after depolarization is plotted. **P < 0.000003. The measurements of 38 spines of four neurons (dendrites) were collected from four independent experiments (C and E). Bar, 1.25 μm.

Mentions: To quantify this spine enlargement, we took advantage of a confocal microscope (Fig. 2). The three dimensional information of the spine of interest was analyzed by optical section (z-series) images collected at 0.2 μm focus intervals. The profile of the z-stack images was sufficient to obtain an unambiguous spine profile (Fig. 2 A). The width of spine heads was measured on the spine profile being thresholded at half maximal fluorescence intensity (Fig. 2 B). The maximum spine width was determined by laying the axis as to run across the widest point of the spine head (Fig. 2 B, gray line). The spine width changed from 1.18 ± 0.0490 μm to 1.36 ± 0.0620 μm (Fig. 2 C; mean ± SEM).


Cadherin activity is required for activity-induced spine remodeling.

Okamura K, Tanaka H, Yagita Y, Saeki Y, Taguchi A, Hiraoka Y, Zeng LH, Colman DR, Miki N - J. Cell Biol. (2004)

Evaluation of spine broadening by confocal microscopy. Z-series profiles of GFP-filled spine were collected at 0.2-μm focus intervals by using a confocal microscope at resting state and 30 min after stimulation (high K+ for 2 min). (A) Z-stack image represents enlargement of the lateral diameter of spine. (B) Z-stack image was thresholded at half maximal fluorescence intensity. An axis was laid as to run across the widest point of spine head (gray line). (C) The spine width measured at the widest point before and 30 min after depolarization is plotted. *P < 0.00002. (D) The single optical section that passes through the maximum spine diameter among z-series images. Note that the maximal optical section showed clear cotyloid shape with similar lateral size to the z-stack image. (E) The spine width measured on the maximal optical section before and 30 min after depolarization is plotted. **P < 0.000003. The measurements of 38 spines of four neurons (dendrites) were collected from four independent experiments (C and E). Bar, 1.25 μm.
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fig2: Evaluation of spine broadening by confocal microscopy. Z-series profiles of GFP-filled spine were collected at 0.2-μm focus intervals by using a confocal microscope at resting state and 30 min after stimulation (high K+ for 2 min). (A) Z-stack image represents enlargement of the lateral diameter of spine. (B) Z-stack image was thresholded at half maximal fluorescence intensity. An axis was laid as to run across the widest point of spine head (gray line). (C) The spine width measured at the widest point before and 30 min after depolarization is plotted. *P < 0.00002. (D) The single optical section that passes through the maximum spine diameter among z-series images. Note that the maximal optical section showed clear cotyloid shape with similar lateral size to the z-stack image. (E) The spine width measured on the maximal optical section before and 30 min after depolarization is plotted. **P < 0.000003. The measurements of 38 spines of four neurons (dendrites) were collected from four independent experiments (C and E). Bar, 1.25 μm.
Mentions: To quantify this spine enlargement, we took advantage of a confocal microscope (Fig. 2). The three dimensional information of the spine of interest was analyzed by optical section (z-series) images collected at 0.2 μm focus intervals. The profile of the z-stack images was sufficient to obtain an unambiguous spine profile (Fig. 2 A). The width of spine heads was measured on the spine profile being thresholded at half maximal fluorescence intensity (Fig. 2 B). The maximum spine width was determined by laying the axis as to run across the widest point of the spine head (Fig. 2 B, gray line). The spine width changed from 1.18 ± 0.0490 μm to 1.36 ± 0.0620 μm (Fig. 2 C; mean ± SEM).

Bottom Line: N-cadherin-venus fusion protein laterally dispersed along the expanding spine head.Overexpression of dominant-negative forms of N-cadherin resulted in the abrogation of the spine expansion.Inhibition of actin polymerization with cytochalasin D abolished the spine expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Osaka University Medical School, Suita, Japan.

ABSTRACT
Neural activity induces the remodeling of pre- and postsynaptic membranes, which maintain their apposition through cell adhesion molecules. Among them, N-cadherin is redistributed, undergoes activity-dependent conformational changes, and is required for synaptic plasticity. Here, we show that depolarization induces the enlargement of the width of spine head, and that cadherin activity is essential for this synaptic rearrangement. Dendritic spines visualized with green fluorescent protein in hippocampal neurons showed an expansion by the activation of AMPA receptor, so that the synaptic apposition zone may be expanded. N-cadherin-venus fusion protein laterally dispersed along the expanding spine head. Overexpression of dominant-negative forms of N-cadherin resulted in the abrogation of the spine expansion. Inhibition of actin polymerization with cytochalasin D abolished the spine expansion. Together, our data suggest that cadherin-based adhesion machinery coupled with the actin-cytoskeleton is critical for the remodeling of synaptic apposition zone.

Show MeSH
Related in: MedlinePlus