ROLE OF AHR/ARNT SIGNALING ON MATRIX REMODELING IN SKIN

AHR/ARNT 信号传导对皮肤基质重塑的作用

• 批准号: 6518008
• 负责人: LORI A WHITE
• 金额: $ 10.62万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518008
• 关键词: biological signal transduction; dioxins; disease /disorder model; gene expression; genetically modified animals; keratinocyte; laboratory mouse; metalloendopeptidases; model design /development; skin disorder; tissue /cell culture; tissue inhibitor of metalloproteinases; toxicant interaction; transcription factor; wound healing

DESCRIPTION (Adapted from the Candidate's Abstract) TCDD exposure leads to severe skin lesions known as chloracne. These lesions are characterized by hyperproliferation, hyperdifferentiation, and abnormal migration of keratinocytes in the stratified squamous epithelia. It is unclear how TCDD exposure leads to the skin pathology. Most of the studies on the molecular mechanisms of TCDD function have focused on the ligand-activated transcription factor AhR/Arnt. Binding of TCDD to AhR initiates heterodimerization with Arnt, and ultimately alters transcription through binding of this complex to specific sites (XRES) in the 5' regions of AhR responsive genes. TCDD target genes identified include the Phase I and Phase II detoxifying enzymes, as well as cytokines (TGF-B, IL-1B), transcription factors (Fos, Jun), and an extracellular matrix remodeling inhibitory proteins (PAI-2). Metabolism of the extracellular matrix is required in situations that require tissue remodeling or cell migration, such as wound healing. The majority of the matrix degradation is accomplished through the activity of members of the matrix metalloproteinase (MMP) family. A transcription factor database search identified two potential XRE sites in the 5' region of MMP-1, and preliminary results demonstrate that MMP-1 MRNA levels increase upon TCDD treatment of keratinocytes. This data suggests a link between TCDD/AhR/Arnt and matrix remodeling. The candidate is currently a post-doctoral fellow in the laboratory of Dr. B. L. Allen-Hoffmann at the University of Wisconsin- Madison, where her project is to generate a tissue specific knockout mouse of AhR in stratified squamous epithelia to study the effects of AhR loss on skin structure and differentiation. The goal of this proposal is to study the skin pathology resulting from TCDD exposure in intact tissue, and determine the role of the AhR/Arnt pathway on MMPs and their inhibitors, the TIMPS, into the affected skin. Therefore the specific aims of this proposal are: (1) create a mouse model, using the Cre/loxP recombination system of bacteriophage P1, to conditionally knock out the Arnt gene in the replicating keratinocytes of murine skin. Use this mouse model, along with the AhR tissue specific knockout, to study the effect of AhR and Arnt loss on MMP/TIMP expression and TCDD skin pathologies. (2) Use keratinocytes in an organotypic cell culture system to study the effect of TCDD on tissue architecture and gene expression of MMPs/TIMPS.

描述（改编自候选人的摘要） 接触 TCDD 会导致严重的皮肤损伤，称为氯痤疮。 这些病变 其特点是过度增殖、过度分化和异常 角质形成细胞在复层鳞状上皮中的迁移。 这是 尚不清楚 TCDD 暴露如何导致皮肤病理。 大多数研究是关于 TCDD功能的分子机制主要集中在配体激活 转录因子 AhR/Arnt。 TCDD 与 AhR 的结合启动 与 Arnt 形成异二聚体，并最终通过以下方式改变转录 该复合物与 AhR 5' 区域中的特定位点 (XRES) 的结合 反应基因。 确定的 TCDD 靶基因包括 Phase I 和 Phase II解毒酶，以及细胞因子（TGF-B、IL-1B）、转录 因子（Fos、Jun）和细胞外基质重塑抑制蛋白 （PAI-2）。 在某些情况下需要细胞外基质的代谢 需要组织重塑或细胞迁移，例如伤口愈合。 这 大部分基质降解是通过以下活性完成的 基质金属蛋白酶 (MMP) 家族的成员。 转录因子 数据库搜索在 MMP-1 的 5' 区域确定了两个潜在的 XRE 位点， 初步结果表明，TCDD 后 MMP-1 mRNA 水平增加 角质形成细胞的治疗。 该数据表明 TCDD/AhR/Arnt 之间存在联系 和矩阵重构。 该候选人目前是博士后研究员 威斯康星大学 B. L. Allen-Hoffmann 博士的实验室- 麦迪逊，她的项目是培育一种组织特异性基因敲除小鼠 复层鳞状上皮中的 AhR 研究 AhR 损失对皮肤的影响 结构和分化。 该提案的目标是研究皮肤 完整组织中 TCDD 暴露引起的病理学，并确定 AhR/Arnt 通路对 MMP 及其抑制剂 TIMPS 的作用 受影响的皮肤。 因此，本提案的具体目标是：（1）创建 小鼠模型，使用噬菌体 P1 的 Cre/loxP 重组系统， 有条件地敲除复制角质形成细胞中的 Arnt 基因 鼠类皮肤。 使用该小鼠模型以及 AhR 组织特异性 敲除，研究 AhR 和 Arnt 缺失对 MMP/TIMP 表达的影响 TCDD 皮肤病理学。 (2) 在器官型细胞培养物中使用角质形成细胞 研究 TCDD 对组织结构和基因表达影响的系统 MMP/TIMPS。