H+ pump-dependent changes in membrane voltage are an early mechanism necessary and sufficient to induce Xenopus tail regeneration
H+ pump-dependent changes in membrane voltage are an early mechanism necessary and sufficient to induce Xenopus tail regeneration
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DOI：
10.1242/dev.02812
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发表时间：
2007-04-01
期刊：
影响因子：
4.6
通讯作者：
Levin, Michael
中科院分区：
文献类型：
--
作者：
Adams, Dany S.;Masi, Alessio;Levin, Michael
在许多系统中，离子流和长期内源性电压梯度调节图案化事件，但分子细节仍然是神秘的。为了建立一个机械的生物物理事件和再生之间的联系，我们研究了离子运输过程中的作用爪蟾尾巴再生。我们表明，活性的V-ATP酶H+泵再生所需的，但不是伤口愈合或尾巴的发展。V-ATP酶在截肢后6小时在现有伤口细胞中特异性上调。V-ATP酶功能的药理学或分子遗传学丧失以及随之而来的强去极化消除了再生而不诱导凋亡。未切割的尾部通常大部分是极化的，整个尾部有离散的去极化细胞群。截肢后，正常的再生芽是去极化的，但到24小时截肢后变得迅速复极化的活性的V-ATP酶，和一个岛的去极化细胞出现在再生芽的前面。相反，相对于未切割或再生的尾巴，非再生“不应”状态的尾芽保持高度去极化。由V-ATP酶功能丧失引起的去极化导致芽中细胞增殖的急剧减少、神经成分的深刻错误模式化和再生失败。至关重要的是，H+通量的诱导足以在其他非再生条件下拯救轴突图案化和尾部生长。这些数据提供了第一个详细的机械合成的生物电，分子和细胞生物学事件的基础上再生的一个复杂的脊椎动物结构，包括脊髓，并提出了一个模型的生物物理和分子步骤的基础上尾部再生。H+流的控制代表了一种非常重要的新模式，与传统的生物化学方法一起，最终可能允许增强再生用于治疗应用。
In many systems, ion flows and long-term endogenous voltage gradients regulate patterning events, but molecular details remain mysterious. To establish a mechanistic link between biophysical events and regeneration, we investigated the role of ion transport during Xenopus tail regeneration. We show that activity of the V-ATPase H+ pump is required for regeneration but not wound healing or tail development. The V-ATPase is specifically upregulated in existing wound cells by 6 hours post-amputation. Pharmacological or molecular genetic loss of V-ATPase function and the consequent strong depolarization abrogates regeneration without inducing apoptosis. Uncut tails are normally mostly polarized, with discrete populations of depolarized cells throughout. After amputation, the normal regeneration bud is depolarized, but by 24 hours post-amputation becomes rapidly repolarized by the activity of the V-ATPase, and an island of depolarized cells appears just anterior to the regeneration bud. Tail buds in a nonregenerative 'refractory' state instead remain highly depolarized relative to uncut or regenerating tails. Depolarization caused by V-ATPase loss-of-function results in a drastic reduction of cell proliferation in the bud, a profound mispatterning of neural components, and a failure to regenerate. Crucially, induction of H+ flux is sufficient to rescue axonal patterning and tail outgrowth in otherwise non-regenerative conditions. These data provide the first detailed mechanistic synthesis of bioelectrical, molecular and cell-biological events underlying the regeneration of a complex vertebrate structure that includes spinal cord, and suggest a model of the biophysical and molecular steps underlying tail regeneration. Control of H+ flows represents a very important new modality that, together with traditional biochemical approaches, may eventually allow augmentation of regeneration for therapeutic applications.