Skin Barrier Adaptation

皮肤屏障适应

• 批准号: 10724505
• 负责人: Cristina de Guzman Strong
• 金额: $ 7.64万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-10 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10724505
• 关键词: Skin; Barrier; Adaptation

ABSTRACT The skin epidermis provides a critical first line of environmental defense. However, the mechanisms mediating how epidermal keratinocytes adapt and respond to the external environment are poorly understood. Involucrin (IVL) is the major scaffold protein of the cornified envelope surrounding the differentiated keratinocyte. Our previous work supports a functional role for involucrin in epidermal adaptive responses to the environment, acute microbial exposure, and inflammation. (1) We discovered recent selective sweep for an IVL haplotype in the northern European (CEU) population. This IVL CEU haplotype is associated with increased IVL expression in sun-exposed skin compared to that in non-sun-exposed skin [according to Genotype-Tissue Expression Project (GTEx) data]. Positive selection of IVL CEU is directly correlated with increasingly northern latitudes, suggesting a fitness benefit of increased IVL expression in northern clines. (2) IVL was the only large Epidermal Differentiation Complex (EDC)-encoded skin barrier protein that exhibited significantly higher levels in the epidermis of conventionally raised (CR) lab mice compared to those in germ-free (GF) and reconstituted skin microbiome (RSM) mice (GF mice acutely exposed to CR commensal microbiota), suggesting an adaptive keratinocyte response to microbial interactions. (3) Ivl-/- mouse skin exhibited a protective effect against MC903-induced inflammation with reduced vitamin D receptor expression, suggesting a regulatory role for IVL in vitamin D signaling in the epidermis. We hypothesize that IVL levels are specifically calibrated to generate an adaptive skin barrier that is finely tuned in response to the environment. We will test this hypothesis by performing three aims. Aim 1. Determine the causative genetic variants that increase IVL gene expression levels. IVL CEU includes enhancer 923 that is required for involucrin target gene expression as evidenced by loss of Ivl expression in 923-/- mice. Cellular and molecular assays in keratinocytes will be performed to identify the molecular mechanisms by which enhancer variation(s) modulate target gene expression. Aim 2. Determine the role of involucrin in the skin adaptive response to commensal microbiota. We will examine the skin and inflammatory responses in rederived Ivl-/- CV mice as a functional measurement of skin adaptation. Aim 3. Determine the molecular mechanism by which involucrin regulates Vitamin D receptor expression and signaling in the epidermis. MC903-treated Ivl-/- ear skins did not exhibit severe inflammation and exhibited reduced Vdr expression. We hypothesize a role for Involucrin to positively regulate Vdr expression and signaling via phosphorylated p38δ, a known VDR activator in other human cell types. Our hypothesis will be rigorously tested using constitutively active p38δ and knockdown in vitro studies with anticipated results for increased and decreased Vdr expression and signaling, respectively. This study will identify the molecular mechanisms involved in human skin barrier evolution and adaptation, which can be developed into innovative therapies for treating skin-barrier impaired inflammatory skin diseases.

抽象的 皮肤表皮提供了关键的环境防御线。但是，介导的机制 表皮角质形成细胞如何适应和响应外部环境。易蛋白酶 （IVL）是围绕分化角质形成细胞的蜂蜜包膜的主要支架蛋白。我们的 以前的工作支持依依赖素蛋白在表皮自适应反应中的功能作用， 急性微生物暴露和炎症。 （1）我们发现最近选择了IVL单倍型的扫描 北欧（CEU）人口。这种IVL CEU单倍型与IVL表达增加有关 在暴露于阳光的皮肤中，与非暴露的皮肤相比[根据基因型 - 组织表达 项目（GTEX）数据]。 IVL CEU的阳性选择与越来越多的北纬度人物直接相关， 表明在北部克莱恩的IVL表达增加的适应性益处。 （2）IVL是唯一的大型 表皮分化复合物（EDC）编码的皮肤屏障蛋白，该蛋白暴露于显着较高的水平 与无菌（GF）相比，在常规饲养（CR）实验室小鼠的表皮中 皮肤微生物组（RSM）小鼠（GF小鼠急性暴露于CR Comensal Microbiota），表明是自适应的 角质形成对微生物相互作用的反应。 （3）IVL - / - 小鼠皮肤暴露了针对的保护作用 MC903诱导的炎症降低了维生素D受体表达，这表明IVL的调节作用 表皮中的维生素D信号传导。我们假设对IVL水平进行了专门校准以生成 一种自适应皮肤屏障，可针对环境响应。我们将通过 执行三个目标。目标1。确定增加IVL基因表达的病因遗传变异 水平。 IVL CEU包括增强剂923，这是依赖蛋白靶基因表达所必需的，这是由 923 - / - 小鼠中IVL表达的丧失。将在角质形成细胞中进行细胞和分子测定，以鉴定 增强子变异调节靶基因表达的分子机制。目标2。确定 依克蛋白在皮肤对共生微生物群的适应性反应中的作用。我们将检查皮肤和 重新IVL - / - CV小鼠的炎症反应作为皮肤适应的功能测量。目标3。 确定富集蛋白调节维生素D受体表达和的分子机制 表皮中的信号传导。 MC903处理的IVL - / - 耳皮不存在严重的感染并暴露 VDR表达降低。我们假设依依赖申蛋白的作用正阳性地调节VDR表达和 通过磷酸化的p38δ发出信号，这是其他人类细胞类型中已知的VDR活化剂的信号。我们的假设将是 严格使用一贯活跃的p38Δ和敲低研究进行了严格测试，并预期结果 VDR表达和信号传导分别增加和降低。这项研究将确定分子 人类皮肤屏障的演变和适应性涉及的机制，可以发展为创新 治疗皮肤性皮肤疾病的治疗疗法。