GPR56/ADGRG1 in peripheral nerve development and repair

摘要 雪旺细胞（SC）是周围神经系统（PNS）的髓鞘形成胶质细胞，与周围神经系统（PNS）相关。 包裹在轴突上形成绝缘的髓鞘。在发育过程中，未成熟的SC选择 适当大小的轴突（一个称为径向分选的过程），并重复地将它们的膜包裹在它们的周围。 选择轴突。SC髓鞘的重要性在SC功能障碍导致的疾病中得到最好的强调， 周围神经病（例如，腓骨肌萎缩症）。生长因子的研究进展 由SC表达的信号分子揭示了神经胶质细胞在神经系统中的无数作用， 细胞间相互作用、与神经元相互作用以及与周围细胞外基质（ECM）相互作用。我们有 先前鉴定粘附G蛋白偶联受体（aGPCR）GPR 56/ADGRG 1为关键调节剂 PNS的发展。斑马鱼和小鼠突变体中Gpr 56功能的丧失导致两种早期 PNS中的发育和后期维持表型。然而，尽管有这些关键功能， 目前尚不清楚是什么发育线索激活了干细胞中的GPR 56。 目的1将确定在发育过程中调节Gpr 56活性的结合伴侣。在其他情况下， GPR 56有两个已知的结合伴侣，ECM蛋白胶原蛋白III和组织转氨酶2。 然而，有趣的是，一个无偏见的蛋白质组学筛选已经确定了额外的候选结合伴侣， PNS中的GPR 56。我们已经通过CRISPR/Cas9介导的方法在这些基因中产生了新的斑马鱼突变体。 基因组编辑，我将进行生化，超微结构和信号分析，以确定 这些候选人在GPR 56活动中的需求。 目的2明确Gpr 56在成人周围神经中的作用。我将确定Gpr 56是否是髓磷脂所必需的 使用诱导型小鼠模型，研究神经损伤后的维持、修复和髓鞘再生。 总之，我的研究可以确定Gpr 56控制PNS发育和修复的机制， 为人类神经病变、髓鞘疾病和神经损伤的新疗法指明了道路。

ABSTRACT Schwann cells (SCs) are the myelinating glia of the peripheral nervous system (PNS) that associate with and wrap around axons to form the insulating myelin sheath. During development, immature SCs select appropriately sized axons (a process termed radial sorting) and repeatedly wrap their membranes around their selected axon. The importance of SC myelin is best underscored in diseases in which SC dysfunction leads to peripheral neuropathies (e.g., Charcot-Marie-Tooth Disease). Advances in identifying growth factors and signaling molecules expressed by SCs reveal the myriad roles of glial cells in the nervous system and their interactions with each other, with neurons, and with the surrounding extracellular matrix (ECM). We have previously identified the adhesion G protein-coupled receptor (aGPCR) GPR56/ADGRG1 as a critical regulator of PNS development. Loss of Gpr56 function in zebrafish and mouse mutants results in both early developmental and later maintenance phenotypes in the PNS. In spite of these key functions, however, it is unclear what developmental cues activate GPR56 in SCs. Aim 1 will determine the binding partners that regulate Gpr56 activity during development. In other contexts, GPR56 has two known binding partners, the ECM proteins collagen III and tissue transglutaminase 2. Interestingly, however, an unbiased proteomics screen has identified additional candidate binding partners for GPR56 in the PNS. We have generated new zebrafish mutants in these genes by CRISPR/Cas9-mediated genome editing, and I will perform biochemical, ultrastructural, and signaling analyses to determine the requirement of these candidates in Gpr56 activity. Aim 2 will define the roles of Gpr56 in adult peripheral nerve. I will determine if Gpr56 is required for myelin maintenance, repair, and remyelination after nerve injury using inducible mouse models. Together, my studies can define mechanisms by which Gpr56 controls PNS development and repair and may suggest roads towards new therapies for human neuropathies, myelin diseases, and nerve injury.