Schwann cell morphology and function in peripheral nerve regeneration

描述（由申请人提供）：在周围神经损伤后，许多患者由于神经再生不足而遭受持续性疼痛或运动障碍。 为了开发促进神经再生的新疗法，必须了解驱动这一过程的细胞和分子机制。许多研究都集中在神经再生中涉及的神经元内在线索，然而周围的细胞类型，如胶质细胞，也在促进轴突再生中发挥重要作用。雪旺细胞是周围神经系统的主要胶质细胞，对轴突的维持和再生至关重要。损伤后，许旺细胞去分化为促进轴突再生和神经修复的未成熟状态。 雪旺细胞的去分化过程伴随着剧烈的形态学变化以及细胞迁移。然而，这些形态学变化究竟是如何由细胞内事件驱动的，如细胞骨架重排和通过细胞内转运的膜重塑，仍然是未知的。 除行为改变外，去分化的雪旺氏细胞还为再生轴突提供生长因子，并提供方向性指导，使轴突沿着正确的路径沿着再生。我们实验室的最新数据表明，经典轴突导向受体突变体，大肠癌（DCC）中的轴突再生，显示出类似于缺乏雪旺细胞的突变体的误导轴突再生。 这表明DCC可能 在引导轴突再生中发挥重要作用，可能以雪旺细胞依赖性方式。 在这里，我建议定义的细胞和分子机制，雪旺细胞促进轴突再生。首先，我将使用活细胞成像来确定雪旺细胞中细胞骨架结构和细胞内转运的变化， 神经损伤 此外，我将确定是否需要在神经再生过程中，使用细胞类型特异性救援的动力蛋白突变体，其中有显着的轴突再生缺陷的许旺细胞的细胞内运输。接下来，我将确定DCC如何促进定向轴突再生。使用活细胞成像，我将监测轴突生长锥的行为 和雪旺细胞在野生型和DCC突变体神经横断后的同时。此外，我将确定在哪种细胞类型（S）DCC需要直接轴突再生使用DCC突变体再生的细胞类型特异性救援。结合起来，拟议的实验将提供细胞和分子机制，雪旺细胞促进体内神经再生。

DESCRIPTION (provided by applicant): Following damage to peripheral nerves, many patients suffer from persistent pain or motor impairments due to inadequate nerve regeneration. In order to develop new therapies to promote nerve regeneration, it is imperative to understand the cellular and molecular mechanisms that drive this process. Many studies have focused on the neuron-intrinsic cues involved in nerve regeneration, however surrounding cell types, such as glial cells, also play an important role in promoting axonal regrowth. Schwann cells are the main glia of the peripheral nervous system and are critical for axonal maintenance and regeneration. Following injury, Schwann cells dedifferentiate to an immature state that promotes axonal regrowth and nerve repair. The process of Schwann cell dedifferentiation is accompanied by drastic morphological changes as well as cell migration. However, exactly how these morphological changes are driven by intracellular events, such as cytoskeletal rearrangements and membrane remodeling via intracellular transport, remains unknown. In addition to behavioral changes, dedifferentiated Schwann cells provide growth factors to regrowing axons and provide directional guidance, allowing axons to regrow along the proper path. The specific guidance molecules that are used by Schwann cells to direct axonal regrowth, however, are unknown. Recent data from our lab demonstrates that mutants for the classical axon guidance receptor, Deleted in Colorectal Carcinoma (DCC), show misguided axonal regrowth similar to that of mutants lacking Schwann cells. This suggests that DCC may play an important role in guiding axonal regrowth, potentially in a Schwann cell-dependent manner. Here, I propose to define the cellular and molecular mechanisms by which Schwann cells promote axonal regrowth. First, I will use live cell imaging to determine how cytoskeletal structure and intracellular transport change in Schwann cells in response to nerve injury. Additionally, I will determine whether intracellular transport is required in Schwan cells during nerve regeneration using cell-type specific rescue of a dynein mutant, which has significant axonal regeneration defects. Next, I will determine how DCC promotes directional axonal regrowth. Using live cell imaging, I will monitor the behavior of axonal growth cones and Schwann cells simultaneously in wild type and DCC mutants following nerve transection. Additionally, I will determine in which cell type(s) DCC is required to direct axonal regrowth using cell-type specific rescue of DCC mutant regeneration. Combined, the proposed experiments will provide cellular and molecular mechanisms by which Schwann cells promote nerve regeneration in vivo.