Ion Channels and Pumps: The Machinery of Electric Signaling at Corneal Wounds

描述（由申请人提供）：角膜上皮细胞迁移和增殖；重要的是，它们这样做是有方向性的，是为了愈合伤口。生长因子和细胞因子在角膜创面愈合中起着关键作用，可能是角膜创面治疗的潜在靶点。我们发现了一个非常不同的因素，即角膜伤口处自然产生的电场（EFs）也能激活细胞内通路。更重要的是，由于电磁场本质上是定向的，它们定向地激活信号通路，给细胞一个定向的提示，并引导细胞向伤口的方向迁移和分裂，以促进愈合。我们的研究表明，电磁场超越了其他被广泛接受的方向线索，如接触抑制释放、伤口空隙、群体压力和趋化性，以指导细胞在一个确定的方向上迁移。内源性EFs是如何产生和调节的尚不清楚。在链脲佐菌素（STZ）诱导的1型糖尿病大鼠和角膜创面愈合缺陷的Pax6+/-突变小鼠中，我们观察到内源性创面EFs显著降低。我们能否增强内源性创面电场来促进创面愈合，特别是难治性和慢性创面？我们的长期目标是阐明利用电信号加速伤口愈合的机制。我们最近观察到伤口电场在损伤后逐渐增加，洗浴液中Cl-或Na+的取代显著改变了内源性电场。因此，我们假设角膜损伤诱导了主动调节的创面电场，创面电场是由特定离子（如Cl-）的通量形成的，这些离子由Cl-通道和运输分子控制；控制Cl-通量可增强内源性电场和伤口愈合。我们将用以下具体目标来检验这一假设：目的1。为了证实伤口电场是对伤害的主动反应。目标2。目的：探讨角膜创面内源性电场的离子机制。目标3。阐明缠绕电场的分子机制。本应用的结果将定义角膜创面愈合中的主动电信号，提供创面愈合中电信号的离子和分子机制，并可能导致利用电信号改善创面愈合的新疗法。

DESCRIPTION (provided by applicant): Corneal epithelial cells migrate and proliferate; importantly they do so directionally, to heal wounds. Growth factors and cytokines play pivotal roles in wound healing and may be potential targets for corneal wound therapies. We have discovered a very different factor, namely naturally-occurring electric fields (EFs) at corneal wounds that also activate intracellular pathways. More significantly, because EFs are intrinsically directional, they activate signaling pathways directionally, giving cells a directional cue and guiding cells to migrate and divide in the direction of the wound to facilitate healing. Our studies have shown that EFs override other well-accepted directional cues such as contact inhibition release, wound void, population pressure and chemotaxis to guide cell migration in a defined direction. How the endogenous EFs are generated and regulated is not known. In streptozotocin (STZ)- induced type 1 diabetes mellitus rats and Pax6+/- mutant mice that have defective corneal wound healing, we observed significantly reduced endogenous wound EFs. Can we enhance the endogenous wound EFs to enhance wound healing, especially in refractory and chronic wounds? Our long-term goal is to elucidate the mechanisms through which electric signals can be exploited to accelerate wound healing. We recently observed that wound EFs increase gradually following injury, and substitution of Cl- or Na+ in the bathing solution significantly alters the endogenous EFs. We thus hypothesize that injury to the cornea induces actively-regulated wound electric fields, which are formed by fluxes of specific ions (e.g. Cl-) that are controlled by Cl- channels and transport molecules; manipulating Cl- flux may enhance endogenous electric fields and wound healing. We will test this hypothesis with the following Specific Aims: Aim 1. To confirm that wound electric fields are an active response to injury. Aim 2. To determine the ionic mechanisms of endogenous EFs at corneal wounds. Aim 3. To elucidate the molecular mechanisms of wound electric fields. The results from this application will define the active electric signaling in corneal wound healing, provide ionic and molecular mechanisms of electric signaling in wound healing, and may lead to novel therapies to improve wound healing exploiting electric signaling. PUBLIC HEALTH RELEVANCE: Persistent corneal epithelial defects pose an important medical problem. We recently discovered a novel signaling mechanism at corneal wounds, namely naturally-occurring electric fields that have profound guidance effects on epithelial cells to heal wounds. This project seeks to determine the ionic and molecular mechanisms controlling ionic fluxes at corneal wounds. The scientific knowledge to be acquired through this project, i.e. how cells regulate this fundamental signal, will open a new avenue to treat delayed and non-healing corneal wounds, and wounds in general.