Defining the Biological Functions of Novel Lipids in Healthy and Wounded Skin

健康的皮肤形成了一个屏障，对于防止感染和身体水分流失至关重要。这种屏障的丧失发生在常见的皮肤病，如牛皮癣和湿疹，并允许在慢性伤口感染。脂质（脂肪）是维持屏障所必需的，但关于它们是如何做到这一点的知之甚少，皮肤脂质在疾病中的作用是一个主要的研究不足的领域。在卡迪夫和范德比尔特，我们发现了几个由皮肤或血细胞产生的脂质家族，这些脂质在对损伤或皮肤病的反应中迁移到皮肤。我们的初步数据表明，其中一些可能对保持皮肤健康和预防疾病很重要。它们由称为脂氧合酶（LOX）的蛋白质（酶）家族制成，包括两种类型的脂质，称为磷脂和神经酰胺。在这项研究中，我们将使用多种方法来确定脂质在调节皮肤生物学中的作用。这些研究可能会导致开发新的治疗方法，用于治疗常见的皮肤病和慢性伤口，这些疾病会导致我们大部分人口的严重发病率。本研究的主要目的是确定卡迪夫和范德比尔特研究小组发现的脂质如何调节皮肤生物学。我们将使用重组人皮肤、小鼠模型和患者样本进行研究，目的：（1）确定脂质在人皮肤中的结构和定位。在这个目标中，我们将确定所有脂质的结构仍然是充分的特点。我们还将使用成像和其他方法来确定脂质位于皮肤中的位置（表皮的哪一层）。健康皮肤和炎症性皮肤病患者的样本都将进行研究。(2)确定脂质如何在分子水平上调节皮肤健康和疾病。我们认为脂质可能通过两种不同的分子过程来帮助调节皮肤。这些包括调节一种叫做过氧化物酶体增殖体激活受体的重要蛋白质，以及通过调节在健康和疾病期间迁移到皮肤中的血细胞的行为。我们将使用3D培养的人类皮肤系统和体内创伤的小鼠模型来研究这些事件。(3)表征LOX衍生脂质对皮肤基因表达的调节。为了确定脂质调节皮肤健康的途径，将使用一种称为siRNA的方法在培养的人类皮肤中去除产生脂质的酶。一种称为RNAseq的全球筛选方法将确定特定皮肤区室中基因表达的变化以及这些变化是如何介导的。(4)发现皮肤病中形成的新脂质。皮肤中存在的脂质的总数和类型是未知的。作为欧洲研究理事会资助的一部分，我们正在开发研究脂质的新方法，这些方法将应用于本项目中我们对皮肤脂质的研究。将对健康皮肤样本以及常见皮肤病、牛皮癣和湿疹患者的活检样本中的脂质进行分类，以确定调节皮肤健康和疾病的新脂质。这些研究将确定脂质如何调节皮肤生物学，并可能导致设计新的治疗炎症性皮肤疾病和伤口的方法。

Healthy skin forms a barrier that is essential for preventing infection and loss of water from our bodies. Loss of this barrier occurs during common skin diseases such as psoriasis and eczema, and allows infection during chronic wounds. Lipids (fats) are required to maintain the barrier, but little is known regarding how they do this, with the role of skin lipids in disease a major under-researched area. In Cardiff and Vanderbilt, we discovered several families of lipids that are generated by skin or by blood cells that migrate to the skin during response to injury, or in skin disease. Our preliminary data suggests that several of these may be important in maintaining the health of skin and preventing disease. They are made by a family of proteins (enzymes) called lipoxygenases (LOXs) and include two types of lipids, called phospholipids and ceramides. In this study we will use a number of approaches to determine the roles of the lipids in regulating skin biology. The studies may lead to development of new treatments for common skin disorders and chronic wounds, conditions that cause significant morbidity in a large section of our population. The primary objective of this study is to determine how lipids discovered by the Cardiff and Vanderbilt groups regulate skin biology. To do this we will use reconstituted human skin, mouse models and patient samples.Aims: (1) Determine the structure and localization of the lipids in human skin. In this aim we will determine the structures of all the lipids still to be fully characterized. We will also use imaging and other methods to determine where the lipids are located in skin (which layers of the epidermis). Both healthy skin and samples from patients with inflammatory skin disorders will be studied. (2) Determine how the lipids regulate skin health and disease at the molecular level. We propose that the lipids may help regulate skin through two different molecular processes. These include regulation of an important protein called PPAR and through regulating how blood cells that have migrated into the skin behave during health and disease. We will study these events using a 3D cultured human skin system, and in a murine model of wounding in vivo. (3) Characterise regulation of skin gene expression by LOX-derived lipids. To identify pathways by which the lipids regulate skin health, the enzymes that generate them will be removed in cultured human skin using an approach called siRNA. A global screening approaches called RNAseq will then determine changes in gene expression in specific skin compartments and how these are mediated. (4) Discover new lipids formed in skin disease. The total number and types of lipids are present in skin is unknown. As part of a European Research Council grant, we are developing new methods for studying lipids that will be applied to our studies of skin lipids in this project. Lipids will be catalogued in samples of healthy skin, and in biopsies from patients with the common skin disorders, psoriasis and eczema, with a view to identifying new lipids that regulate skin health and disease. These studies will determine how lipids regulate skin biology, and may lead to design of new therapies for inflammatory skin diseases and wounds.