Connexins in Nerve Regeneration and Inherited Neuropathy

连接蛋白在神经再生和遗传性神经病中的作用

• 批准号: 7110311
• 负责人: CHARLES K ABRAMS
• 金额: $ 15.19万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7110311
• 关键词: Schwann cells; apoptosis; cell morphology; cell proliferation; electron microscopy; electrophysiology; gap junctions; hereditary peripheral nervous system disorder; laboratory mouse; membrane channels; morphometry; myelination; nervous system regeneration; northern blottings; small interfering RNA; terminal nick end labeling; tissue /cell culture; transcription factor; voltage /patch clamp; western blottings

DESCRIPTION (provided by applicant): A fundamental principle underlying this grant is that connexin 32 (Cx32) is required for normal function of Schwann cells. Though mutations in Cx32 cause alterations in channel function and are clearly associated with the X-Linked Charcot-Marie-Tooth Disease (CMTX), the pathogenesis of this disorder remains to be elucidated. The localization of Cx32 to the paranodes and Schmidt-Lantermann incisures of the myelinating Schwann cell has lead to the hypothesis that Cx32 forms reflexive gap junctions within noncompact myelin and provides a "short circuit" pathway between the ab- and adaxonal cytoplasm of the myelinating Schwann cell. However, data suggest that: 1) mice lacking Cx32 show reduced capacity for regeneration associated myelination; 2) Cx32 is expressed and regulated in cultures of primary Schwann cells; 3) Schwann cells expressing two different mutant forms of Cx32 have strikingly different effects on regeneration in a xenograft model and 4) Schwann cells cultured from Cx32 knockout mice show increased death. These findings lead to the hypothesis that Cx32 is required for normal function of non-myelin-associated Schwann cells, especially those that are proliferating in response to nerve injury and participating in nerve regeneration. Aim 1 will use morphometry, whole animal electrophysiology and behavioral and biochemical assessments to examine the hypothesis that loss of Cx32 is detrimental to normal regenerative Capacity. Aim 2 will use Schwann cell culture and the dual patch clamp technique to examine the hypothesis that: 1) Cx32 is functionally expressed in proliferating adult Schwann cells in primary culture; 2) its expression levels are regulated by GGF (which is thought to induce Schwann cell proliferation during Wallerian degeneration); and 3) loss of Cx32 mediated cell-cell channels leads to increased Schwann cell death. Aim 3 will use primary Schwann cells in culture and the nerve transection model to examine the hypotheses that expression of Cx32 is required to prevent apoptotic cell death and/or limit proliferation of Schwann cells. The experiments outlined in this proposal should play a key role in understanding the role of Cx32 in the Schwann cell and how mutations in Cx32 lead to inherited peripheral neuropathy.

描述（由申请人提供）： 这项资助的基本原则是连接蛋白 32 (Cx32) 是雪旺细胞正常功能所必需的。尽管 Cx32 突变会导致通道功能改变，并且与 X 连锁腓骨肌萎缩症 (CMTX) 明显相关，但这种疾病的发病机制仍有待阐明。 Cx32 定位于有髓鞘雪旺细胞的节旁和 Schmidt-Lantermann 切口，导致了这样的假设：Cx32 在非致密髓鞘内形成反射性间隙连接，并在有髓鞘雪旺细胞的 ab 和 adaxon 细胞质之间提供“短路”途径细胞。 然而，数据表明：1) 缺乏 Cx32 的小鼠表现出与髓鞘形成相关的再生能力降低； 2) Cx32在原代雪旺细胞培养物中表达和调节； 3) 表达两种不同 Cx32 突变形式的施万细胞对异种移植模型中的再生具有显着不同的影响，4) 从 Cx32 敲除小鼠培养的施万细胞显示死亡增加。这些发现导致了这样的假设：Cx32 是非髓磷脂相关雪旺细胞正常功能所必需的，尤其是那些因神经损伤而增殖并参与神经再生的细胞。目标 1 将使用形态测量、整体动物电生理学以及行为和生化评估来检验 Cx32 缺失不利于正常再生能力的假设。目标 2 将使用雪旺细胞培养和双膜片钳技术来检验以下假设：1) Cx32 在原代培养物中增殖的成体雪旺细胞中功能性表达； 2）其表达水平受GGF调节（被认为在华勒变性期间诱导雪旺细胞增殖）； 3) Cx32 介导的细胞-细胞通道的丧失导致雪旺细胞死亡增加。目标 3 将使用培养中的原代雪旺细胞和神经横断模型来检验以下假设：需要 Cx32 的表达来防止细胞凋亡和/或限制雪旺细胞的增殖。该提案中概述的实验应该在理解 Cx32 在雪旺细胞中的作用以及 Cx32 突变如何导致遗传性周围神经病方面发挥关键作用。