Understanding Skin Tissue Repair in Live Mammals

摘要 皮肤保护我们的身体免受外界环境的伤害，它在受伤时的修复能力直接 与疾病和生存息息相关。如果不能妥善修复受伤的组织，可能会导致严重的损伤， 例如慢性伤口的形成，这与严重的并发症甚至死亡有关。 在美国，大约有650万人患有慢性无法愈合的皮肤伤口，如糖尿病 溃疡。至少 每年花费250亿美元治疗慢性伤口，这一成本正在飙升，原因是 不断增加的医疗保健费用、老龄化的人口以及糖尿病、癌症和肥胖率的不断上升。因此， 慢性伤口给公共卫生和医疗保健系统带来了沉重的负担。 我们仍然缺乏不同的细胞行为的基本知识，这些行为是协调的，以实现组织 再生和修复。这项提议的目标是解开细胞行为是如何被恰当地编排在 修复过程中的单细胞和组织尺度水平。解决这些根本问题的关键障碍 问题在于无法研究完整哺乳动物的这些动态过程。进一步，审问皮肤 修复的复杂性是共存的上皮干细胞和常驻免疫细胞混合在一起，两者都 在修复过程中有牵连。为此，我的实验室已经建立了体内策略来 直接可视化和操纵活体小鼠皮肤上皮细胞和免疫细胞，服用 其独特的可访问性、在其整个生命周期内不断更新和高效维修的优势。 我们利用一种新的非侵入性双光子成像方法跟踪上皮细胞和免疫细胞。 在维修过程中。我们将活体显微镜与我们开发的操纵方法相结合 体内不同的上皮细胞修复行为或驻留细胞类型。这种集成的方法使我们能够 剖析不同细胞活动、群体和相互作用的协调和功能意义 修理。因此，我们已经开始了解不同的上皮细胞行为之间的复杂相互作用，以及 在表皮内不同的细胞类型之间，有助于伤口闭合。 这项提议的目标是促进我们对细胞群体和行为的理解 通过使用尖端成像的集成方法，协调实现皮肤伤口修复 技术、基因操作和细胞生物学。鉴于伤口修复的许多方面都是广泛的 保存在其他器官中，我们的发现也将与其他组织相关，并将提供重要的 改善各种患者伤口修复的基础。

SUMMARY Skin protects our body against the outer environment, and its ability to repair upon injury is directly connected to both disease and survival. Failure to properly repair injured tissue can result in severe damage, such as the formation of chronic wounds, which are associated with severe complications and even death. Approximately 6.5 million people in the US suffer from chronic non-healing skin wounds, such as diabetic ulcers. At least US$25 billion is spent annually to treat chronic wounds, and this cost is skyrocketing due to increasing health care costs, an aging population and the growing rates of diabetes, cancer and obesity. Thus, chronic wounds represent a substantial burden on public health and the health care system. We still lack fundamental knowledge of distinct cellular behaviors that are coordinated to achieve tissue regeneration and repair. The goal of this proposal is to unravel how cell behaviors are properly orchestrated on the single-cell and tissue-scale level during repair. The critical barrier to addressing these fundamental questions lies in the inability to study these dynamic processes in an intact mammal. Further, interrogating skin repair is complicated by the coexistence epithelial stem cells intermixed with resident immune cells, both of which are implicated in the repair process. To this end, my laboratory has established an in vivo strategy to directly visualize and manipulate epithelial cells and immune cells in the skin epithelium of live mice, taking advantage of its unique accessibility, continuous regeneration throughout its lifetime, and efficient repair. We utilize a novel, non-invasive two-photon imaging approach to follow epithelial and immune cells during the repair process. We combine intravital microscopy with methods that we developed to manipulate distinct epithelial cell repair behaviors or resident cell types in vivo. This integrated approach allows us to dissect the coordination and functional significance of distinct cell activities, populations and interactions during repair. Thus, we have begun to understand the complex interplay between distinct epithelial cell behaviors, and between distinct cell types within the epidermis, that contribute to wound closure. The goal of this proposal is to advance our understanding of how cell populations and behaviors are orchestrated to achieve wound repair in skin, by using an integrated approach of cutting edge imaging technology, genetic manipulation and cell biology. Given that many aspects of wound repair are widely conserved in other organs, our findings will be relevant to other tissues as well, and will provide an important foundation to improve wound repair in a variety of patients.