Trans-synaptic mechanism of retinal synapse formation and function

视网膜突触形成和功能的跨突触机制

• 批准号: 10426669
• 负责人: Yuchen Wang
• 金额: $ 4.43万
• 依托单位: SCRIPPS FLORIDA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10426669
• 关键词: Adhesions; Adopted; Advanced Development; Affect; Affinity; Axon; Binding; Calcium Channel; Cell Adhesion Molecules; Complex; Cone; Cone dystrophy; Couples; Deletion Mutagenesis; Development; Electrophysiology (science); Electroporation; Goals; In Vitro; Inner Plexiform Layer; Leucine-Rich Repeat; Mediating; Mentors; Molecular; Morphology; Neural Retina; Neurons; Night Blindness; Pathology; Phase; Photoreceptors; Play; Proteins; Receptor Signaling; Reporting; Research; Retina; Retinal Diseases; Rod; Role; Site; Synapses; Synaptic Receptors; Techniques; Testing; Transplantation; Work; base; cell type; extracellular; in vivo; information processing; innovation; insight; leucine-rich repeat protein; mutant; neural circuit; neurotransmitter release; receptor; retinal neuron; retinal rods; ribbon synapse; synaptic function; synaptogenesis; therapeutic development; trafficking; transplantation therapy; visual information; visual performance

PROJECT SUMMARY/ABSTRACT Our optimal visual performance starts with the correct parallel visual information processing in the retina which depends on precise retinal neural circuit formation. To achieve this, retinal neurons must accurately set up functional synapses which require precise alignment between the pre-synaptic neurotransmitter releasing site and the post-synaptic receptor. Increasing evidence suggests that cell adhesion molecules (CAMs)-mediated trans-synaptic complexes are critical for synapse formation and function, however, the mechanism how pre- synaptic releasing machinery coordinates with the post-synaptic receptor signaling complex at retinal ribbon synapses is largely unknown. We recently reported that the extracellular calcium channel auxiliary subunit α2δ4 is necessary for rod photoreceptor axonal elaboration and synapse formation and demonstrated that α2δ4 does so through controlling the synaptic targeting of ELFN1, a leucine-rich repeat (LRR) protein specifically expressed at rod synapse and interacts trans-synaptically with the post-synaptic mGluR6 receptor. We also showed that α2δ4 interacts with ELFN1 through the LRR domain, a conserved domain shared across many LRR proteins. Interestingly, we and other lab identified another LRR protein termed LRIT1, which specifically affects cone synaptic function. The objective of the proposed work is to determine whether it is a general mechanism that pre-synaptic calcium channel complex utilizes α2δ4 to coordinate with post-synaptic receptor through the facilitation of different LRR proteins. In Aim 1, we will determine the functional role of α2δ4-ELFN1 interaction in rod synapse formation using in vivo electroporation combined with deletion mutagenesis. In Aim 2, we will study how LRIT1 regulates cone synaptic function by testing whether LRIT1 affects pre-synaptic Cav1.4 channel activity through α2δ4 using electrophysiological recording. In Aim 3, I will investigate whether synapses in the inner plexiform layer (IPL) also adopt similar trans-synaptic mechanism by studying how α2δ4 and LRIT1 affect RBC-AII amacrine synapse formation and function using the technique gained during the mentored phase. This proposal is innovative because no mechanistic studies has been done on α2δ4 protein despite its clearly important role in photoreceptor synapse formation and function. The proposed work is significant since results from this study will enable better understanding of how retinal neurons establish and maintain synaptic contact.

项目总结/摘要 我们最佳的视觉表现始于视网膜中正确的平行视觉信息处理， 取决于精确的视网膜神经回路的形成。为了实现这一点，视网膜神经元必须准确地建立 功能性突触，其需要突触前神经递质释放位点之间的精确对准 和突触后受体。越来越多的证据表明，细胞粘附分子（CAM）介导的 跨突触复合物对突触的形成和功能至关重要，然而， 突触释放机制与视网膜带处的突触后受体信号复合体协调 突触在很大程度上是未知的。我们最近报道，细胞外钙通道辅助亚单位， α2δ4是视杆细胞轴突加工和突触形成所必需的，并证明， α2δ4通过控制ELFN 1的突触靶向来实现这一点，ELFN 1是一种富含亮氨酸的重复序列（LRR）蛋白 在视杆突触特异性表达，并与突触后mGluR 6受体跨突触相互作用。 我们还发现，α2δ4通过LRR结构域与ELFN 1相互作用，LRR结构域是一个保守的结构域， 许多LRR蛋白。有趣的是，我们和其他实验室发现了另一种LRR蛋白，称为LRIT 1， 特别影响锥状突触功能拟议工作的目标是确定它是否是一个 突触前钙通道复合体利用α2δ4与突触后钙通道协调的一般机制 受体通过不同的LRR蛋白的促进。在目标1中，我们将确定 α2δ4-ELFN 1在视杆突触形成中的相互作用 诱变在目标2中，我们将通过测试LRIT 1是否能够调节视锥突触功能来研究LRIT 1是如何调节视锥突触功能的。 使用电生理记录，通过α2δ4影响突触前Cav1.4通道活动。在目标3中，我将 研究内丛状层（IPL）中的突触是否也采用类似的跨突触机制， 研究α2δ4和LRIT 1如何影响RBC-AII无长突突触的形成和功能， 在指导阶段获得的。这一建议是创新的，因为没有进行机理研究 尽管α2δ4蛋白在光感受器突触的形成和功能中具有明显的重要作用，的 建议的工作是重要的，因为这项研究的结果将使更好地了解视网膜如何 神经元建立并维持突触接触。