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: 7490259
• 负责人: CHARLES K ABRAMS
• 金额: $ 14.5万
• 依托单位: SUNY DOWNSTATE MEDICAL CENTER
• 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 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7490259
• 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）： 该赠款基础的基本原理是雪旺细胞的正常功能需要连接蛋白32（CX32）。尽管CX32中的突变会导致通道功能的改变，并且显然与X连锁的Charcot-Marie-Marie-Tooth疾病（CMTX）有关，但这种疾病的发病机理仍有待阐明。 CX32将骨髓化的schwann细胞的骨瘤和施密特 - 兰特曼切口定位导致了以下假设：CX32形成了非肌电髓磷脂内的反射缝隙连接，并提供了AB-和辅助性细胞之间的“短路”途径。 但是，数据表明：1）缺乏CX32的小鼠显示再生能力降低相关的髓鞘化； 2）CX32在原代雪旺细胞的培养物中表达并调节； 3）表达两种不同突变形式的CX32的Schwann细胞对异种移植模型中的再生有明显不同的影响，4）从CX32敲除小鼠培养的Schwann细胞显示死亡增加。这些发现导致了以下假设：非肌蛋白相关的雪旺细胞的正常功能需要CX32，尤其是那些响应神经损伤并参与神经再生而增殖的细胞。 AIM 1将使用形态计量学，整个动物电生理学以及行为和生化评估来检查CX32损失对正常再生能力有害的假设。 AIM 2将使用Schwann细胞培养和双贴片夹技术来检查以下假设：1）Cx32在原发性培养的成年成年schwann细胞中在功能上表达； 2）其表达水平受GGF的调节（被认为在沃勒（Wallerian）变性过程中会诱导Schwann细胞增殖）； 3）CX32介导的细胞细胞通道的丧失导致Schwann细胞死亡增加。 AIM 3将在培养和神经横向模型中使用原代雪旺细胞来检查CX32的表达以防止凋亡细胞死亡和/或限制Schwann细胞的增殖。该提案中概述的实验应在理解CX32在Schwann细胞中的作用以及CX32中的突变如何导致遗传的周围神经病中起关键作用。