Mechanism of Keratinocyte Motility

描述(由申请人提供)： 人角质形成细胞(HK)的运动是伤口愈合过程中的关键事件。直接影响香港移民的生物因素还没有完全了解。正在愈合的皮肤伤口的微环境要求设计实验，直接检查伤口环境的要素并评估它们的影响。我们的三个独立的、电脑辅助的香港移民测试能够分析香港的动力和香港的增殖。我们证明了与HK并列的结缔组织成分的类型对HK的迁移有重大影响。在上一个周期中，我们的数据支持一种范式，即细胞外基质(ECM)可以在没有生长因子(GFS)的情况下启动香港的迁移，即所谓的“ECM发起的”运动或触觉趋化。政府飞行服务队不能启动香港运动。需要选定的GF来增强和优化ECM启动的迁移。低氧还增加了HK在ECM上的迁移。这与半渗透性闭塞敷料治疗人类皮肤伤口的情况是一致的，这种敷料促进了再上皮化，但使伤口的氧分压低到无法估量的程度。因此，我们确定了深刻影响HK运动的三个可分离的生物因素：细胞外基质、GFS和低氧。在上一个周期中，我们重点研究了低氧如何在细胞水平上促进HK的运动。我们发现，低氧并不影响HK整合素的表达，但降低了HK来源的层粘连蛋白1和5(2个运动“刹车”)，并增加了板脂相关蛋白Ezrin、moesin和Radiox.它还增加了选择的基质金属蛋白酶，如基质金属蛋白酶-9。我们还确定了HK运动所需的4条重要信号通路--p38 MAP激酶、ERK 1/2、PKC Delta和FAK驱动的信号通路。在这项建议中，我们希望确定(I)是否通过我们已确定的对HK迁移必需的四条途径中的一条或多条来介导低氧增强的运动，以及是否通过ECM启动、GF增强的运动或两者兼而有之来介导低氧增强的运动，以及(Ii)哪些信号通路负责细胞、形态、结构和运动所需的机制，如焦点黏附转换、瓣膜形成和细胞极化。最后，在我们的第三个目标中，我们将开发一种新的动物模型来检验我们体外数据的准确性。这个模型将由基因工程人类皮肤的等价物移植到无毛小鼠身上。

DESCRIPTION (provided by applicant): Human keratinocyte (HK) motility is a critical event in the process of wound healing. The biological elements that directly influence HK migration are incompletely understood. The microenvironment of the healing skin wound dictates experiments be designed that directly examine elements of the wound environment and evaluate their influence. Our 3 independent, computer-assisted HK migration assays are able to dissect HK motility from HK proliferation. We demonstrated that the type of connective tissue components juxtaposed to the HK has a major influence upon HK migration. In the last cycle, our data support a paradigm in which extracellular matrices (ECMs) can initiate HK migration in the absence of growth factors (GFs), so-called "ECM-initiated" motility or haptotaxis. GFs cannot initiate HK motility. Selected GFs are needed to enhance and optimize ECM-initiated migration. Hypoxia also increases HK migration on ECMs. This is in accordance with human skin wounds treated by semi-permeable occlusive dressings which promote re-epithelialization but make the wound oxygen tension immeasurably low. Therefore, we have identified 3 separable biological elements that profoundly influence HK motility: ECMs, GFs and hypoxia. During the last cycle, we focused on how hypoxia promotes HK motility at the cellular level. We found that hypoxia did notjalter the HK integrin profile, but decreased HK-derived laminins 1 and 5 (2 motility "brakes") and increased the lamellipodia-associated proteins - ezrin, moesin and radixin. It also increased selected matrix metalloproteinases such as MMP-9. We also identified 4 important signaling pathways needed for HK motility--p38 MAP kinase, ERK 1/2, PKC delta and FAK-driven signaling. In this proposal, we wish to determine (i) if hypoxia-enhanced motility is mediated via one or more of the 4 pathways we've identified as necessary for HK migration and if hypoxia-enhanced motility is mediated via ECM-initiated, GF-enhanced motility or both and (ii) which signaling pathways are responsible for cellular, morpholological, structural, mechanisms needed for motility such as focal adhesion turnover, lamillipodia formation, and cell polarization. Lastly, in our Third Aim, we will develop a novel animal model to examine the veracity of our in vitro data. This model will consist of genetically engineered human skin equivalents grafted onto hairless mice.