Determining the role of type I interferons in ultraviolet-B light induced keratinocyte death

项目总结/摘要 红斑狼疮是一种慢性的，使人衰弱的自身免疫性疾病， 育龄妇女，而且已被发现是这一人口的主要死亡原因之一。全身 系统性红斑狼疮（SLE）是一种疾病，具有异质性的临床表现， 几乎影响身体的所有主要器官。当有皮肤受累时，疾病被归类为 皮肤红斑狼疮（CLE）。CLE可以单独发生，也可以与系统性 高达70%的SLE患者出现皮肤受累。SLE和CLE都是 其特征在于对紫外（UV）光的敏感性增加。紫外线可以引发皮肤和全身 严重降低患者生活质量并带来重大经济负担的疾病突发。为 驱动这些反应的机制尚不清楚，几乎没有治疗选择，主要是预防 基于避免阳光照射和使用防晒霜。I型干扰素（IFN）是一组细胞因子，通常产生 在狼疮患者中长期过表达，其循环水平与 具有皮肤病活性。I型干扰素调节几种基因的表达，这些基因可能在 光敏性，包括促凋亡Xaf 1和促进自然杀伤（NK）细胞募集的趋化因子 和激活。Kahlenberg实验室先前观察到，I型干扰素（IFN）在 在SLE角质形成细胞（KC）中的基线水平，并在UV暴露后促进细胞死亡。然而，具体的途径 由I型IFN调节的增强UV驱动的KC死亡的基因尚不清楚。这项提案将检验这一假设 狼疮皮肤中I型干扰素的慢性过度表达使角质形成细胞增加UVB诱导的 外源性凋亡通过上调XAF 1表达和增强募集和激活 细胞毒性NK细胞。这一假设将通过三个具体的目标进行测试：（1）检查激活的外源性 vs. UVB暴露后I型IFN引发的皮肤中的内源性细胞凋亡，（2）确定XAF 1在I型IFN引发的皮肤中的作用。 I型IFN诱导的KC凋亡;（3）确定NK细胞在I型IFN诱导的KC凋亡中的作用。完成 这些特定目标、人类细胞系和基因工程小鼠模型将用于体外实验 以及研究暴露于以下物质的I型IFN-致敏的KCs的细胞信号传导和遗传调节的体内实验： 紫外线，并确定这是如何影响NK细胞招募到皮肤。结果从这些 研究将确定I型IFN在狼疮皮肤中过度产生的影响， 未来的总体目标是为那些因疾病发作而死亡的患者确定新的治疗方案的目标， 太阳这个项目将作为一个重要的机制，通过它申请人将进一步扩大她的核心技能 实验设计和数据分析，专业发展和科学交流。宽敞的 密歇根大学的可用资源以及经验丰富的导师和合作者将确保 申请人能够成功完成拟议的研究和培训计划。

PROJECT SUMMARY/ABSTRACT Lupus erythematosus is a chronic, debilitating autoimmune disease that disproportionately affects women of childbearing age and has been found to be among the leadings causes of death in this population. The systemic form of the disease, systemic lupus erythematosus (SLE), has heterogeneous clinical manifestations that can affect nearly all major organs of the body. When there is skin involvement, the disease is grouped under the category of cutaneous lupus erythematosus (CLE). CLE can occur on its own or in combination with systemic disease with up to 70% of SLE patients experiencing cutaneous involvement. Both SLE and CLE are characterized by increased sensitivity to ultraviolet (UV) light. UV light can trigger cutaneous and systemic disease flares that severely diminish patient quality of life and carry significant economic burdens. As the mechanisms driving these responses are not understood, few treatment options exist with prevention largely based on sun avoidance and sunscreen use. Type I interferons (IFNs), a group of cytokines generally produced in response to viral infection, are chronically overexpressed in lupus patients with circulating levels correlating with cutaneous disease activity. Type I IFNs regulate expression of several genes that may play a role in photosensitivity including pro-apoptotic Xaf1 and chemokines that promote natural killer (NK) cell recruitment and activation. The Kahlenberg laboratory previously observed that type I interferons (IFNs) are increased at baseline in SLE keratinocytes (KCs) and promote cell death after UV exposure. However, the specific pathways regulated by type I IFNs that enhance UV-driven KC death are not known. This proposal will test the hypothesis that chronic overexpression of type I IFNs in lupus skin primes keratinocytes for increased UVB-induced extrinsic apoptosis through upregulated XAF1 expression and enhanced recruitment and activation of cytotoxic NK cells. This hypothesis will be tested through three specific aims: (1) Examine activation of extrinsic vs. intrinsic apoptosis in type I IFN-primed skin following UVB exposure, (2) Determine the role of XAF1 in type I IFN-driven KC apoptosis, and (3) Identify the role of NK cells in type I IFN-driven KC apoptosis. To accomplish these specific aims, human cell lines and genetically engineered mouse models will be used to perform in vitro and in vivo experiments investigating cell signaling and genetic regulation of type I IFN-primed KCs exposed to UV light and to determine how this influences NK cells that are recruited into the skin. The results from these studies will establish the impacts of type I IFN overproduction in lupus skin in the context of photosensitivity with the overall future goal of identifying targets for new treatment options for patients whose disease is flared by the sun. This project will serve as a crucial mechanism through which the applicant will further expand her core skills in experimental design and data analysis, professional development, and scientific communication. The ample resources available at the University of Michigan together with experienced mentors and collaborators will ensure the applicant is able to successfully complete the proposed research and training plans.