Role for cell adhesion and glycosyl (HNK-1 and oligomannoside) recognition in the sharpening of the regenerating retinotectal projection in goldfish.
Role for cell adhesion and glycosyl (HNK-1 and oligomannoside) recognition in the sharpening of the regenerating retinotectal projection in goldfish.
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细胞粘附和糖基（HNK-1 和寡甘露糖苷）识别在金鱼视网膜顶盖投射再生锐化中的作用。
DOI：
10.1002/(sici)1097-4695(199812)37:4
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Schachner,M
中科院分区：
文献类型：
--
作者：
Schmidt,JT;Schachner,M
细胞粘附分子（cam）被认为在神经系统的发育和可塑性中起着至关重要的作用。本研究测试了细胞粘附的作用，特别是对两个糖基表位（HNK‐1和寡甘草醇苷）在金鱼视网膜再生纤维形成的视网膜定位图的活性驱动锐化中的识别。HNK‐1是许多cam和细胞外基质（ECM）分子上的一个突出的糖基表位，包括NCAM、L1、室管ymin和整合素，它们都与突触可塑性有关。为了测试HNK‐1在锐化过程中的作用，我们使用渗透性微型泵将HNK‐1抗体从视神经挤压后18天开始注入顶脑室7-21天。压伤后76-86天记录的视网膜定位图显示缺乏锐化，这与之前使用两种室管ymin抗体（脑脊液中存在HNK‐1阳性的ECM成分）所见相似。每个点的多单元感受野平均为26°，而注入对照抗体或单独注入林格氏抗体的再生细胞为11-12°。HNK‐1表位也与层粘连蛋白的G2结构域结合，介导神经元- ECM的粘附。为了测试层粘连蛋白的作用，同样注入了多克隆抗体，也阻止了大约相同程度的锐化。结果支持HNK‐1表位和层粘连蛋白在视网膜锐化中的作用。CAM L1上的寡糖甘露皂苷表位（被单克隆抗体L3识别）与同一细胞上的NCAM相互作用，促进细胞间更强的L1亲性相互作用。L1样分子和NCAM在鱼的再生视网膜系统中都有显著的重表达。输注寡甘醇糖肽导致锐化降低，多单位接受野平均为22.7°。甘露糖贫糖肽的输注不太明显地破坏了锐化，平均多单元感受野为18°。因此，寡糖聚糖尤其可能在视网膜斑点锐化中起作用。阻断糖介导的cam和ECM分子之间的相互作用可能会降低视网膜轴突侧枝的探索性生长程度，阻止它们找到视网膜定位位点，或者可能干扰L1或NCAM和层粘连蛋白在突触密度上的结合，从而阻止视网膜定位合适的突触的稳定。总之，这些结果支持细胞粘附和聚糖表位在视觉突触可塑性中的突出作用。©1998 John Wiley & Sons, Inc中国生物医学工程杂志（英文版），1998
Cell‐adhesion molecules (CAMs) are thought to play crucial roles in development and plasticity in the nervous system. This study tested for a role for cell adhesion and in particular, the recognition of two glycosyl epitopes (HNK‐1 and oligomannoside) in the activity‐driven sharpening of the retinotopic map formed by the regenerating retinal fibers of goldfish. HNK‐1 is a prominent glycosyl epitope on many CAMs and extracellular matrix (ECM) molecules, including NCAM, L1, ependymin, and integrins, which have all been implicated in synaptic plasticity. To test for a role of HNK‐1 in the sharpening process, we used osmotic minipumps to infuse HNK‐1 antibodies for 7–21 days into the tectal ventricle starting at 18 days after optic nerve crush. Retinotopic maps recorded at 76–86 days postcrush showed a lack of sharpening similar to that seen previously with two antibodies to ependymin, an HNK‐1–positive ECM component present in cerebrospinal fluid. The multiunit receptive fields at each point averaged 26° versus 11–12° in regenerates infused with control antibodies or Ringer's alone. The HNK‐1 epitope also binds to the G2 domain of laminin to mediate neuron‐ECM adhesion. To test for a role for laminin, a polyclonal antibody was similarly infused and also prevented sharpening to approximately the same degree. The results support a role for the HNK‐1 epitope and laminin in retinotectal sharpening. The oligomannoside epitope (recognized by monoclonal antibody L3) on the CAM L1 interacts with NCAM on the same cell to promote stronger L1 homophilic interactions between cells. Both an L1‐like molecule and NCAM are prominently reexpressed in the regenerating retinotectal system of fish. Infusion of oligomannosidic glycopeptides resulted in decreased sharpening, with multiunit receptive fields that averaged 22.7°. Infusions of mannose‐poor glycopeptides less prominently disrupted sharpening, with average multiunit receptive fields of 18°. Thus, oligomannosidic glycans in particular may play a role in retinotopic sharpening. Blocking glycan‐mediated interactions between CAMs and ECM molecules could decrease the extent of exploratory growth of retinal axon collaterals, preventing them from finding their retinotopic sites, or could interfere with L1 or NCAM and laminin binding at the synaptic densities preventing stabilization of retinotopically appropriate synapses. Together, these results support a prominent role for cell adhesion and glycan epitopes in visual synaptic plasticity. © 1998 John Wiley & Sons, Inc. J Neurobiol 37: 659–671, 1998