Epigenetic regulation of epidermal proinflammatory responses

表皮促炎症反应的表观遗传调控

• 批准号: 10931159
• 负责人: KATIA GEORGOPOULOS
• 金额: $ 65.14万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-22 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10931159
• 关键词: Acceleration; Address; Architecture; Basal Cell; Cells; Chromatin; Chromatin Structure; Chromosomes; Clone Cells; Complex; DNA; Deacetylase; Defect; Enhancers; Ensure; Environment; Epidermis; Epigenetic Process; Evolution; Gene Activation; Gene Expression; Genes; Genetic Transcription; Genome; Grant; Heritability; Heterogeneity; Homeostasis; Human; Immune; In Vitro; Inflammatory; Inflammatory Response; Kinetics; Lead; Maintenance; Mediating; Memory; Modification; Molecular Conformation; Mus; Nuclear; Nucleic Acid Regulatory Sequences; Nucleosomes; Physiological; Post-Translational Protein Processing; Process; Proteins; Recurrence; Repression; Research; Resolution; Rest; Role; Signal Transduction; Site; Skin; Specificity; Stratum Basale; Stress; Testing; Tissues; Transcription Factor AP-1; Transcriptional Activation; Transcriptional Regulation; Translating; Work; biological adaptation to stress; chromatin remodeling; derepression; epigenetic memory; epigenetic regulation; epithelial stem cell; gene induction; gene repression; histone modification; in vivo; insight; keratinocyte; physiologic stressor; posttranscriptional; practical application; preservation; promoter; recruit; repaired; response; skin barrier; skin disorder; transcription factor

ABSTRACT It has been argued that keratinocytes at the interface of the body with the outside world have developed specialized mechanisms to fulfill the need to nimbly respond to an ever-changing array of challenges with rapid and reversible gene activation. Our past studies support the hypothesis that signaling information pertaining to skin environmental insults is rapidly translated at repressed enhancers of stress response genes into chromatin changes leading to their temporary induction. We have shown that the Mi-2β/NuRD complex sets a chromatin environment that restricts transcription at genes that will be induced in keratinocytes by stress signals, holding them silent but poised for rapid activation. Our studies highlight a dynamic switch between chromatin remodelers that restrict gene expression and early response factors that support transcriptional activation. The mechanisms that support this temporal switch and their contribution to response memory are investigated. In Aim 1, we study how Mi-2β/NuRD is tethered to stress response loci in homeostasis, removed during the stress response, and returned during resolution. We test whether Mi-2β/NuRD is targeted to these loci by stable association with TFs, using both unbiased approaches and a focused approach on the AP1 complex. We characterize post-transcriptional modifications (PTMs) of Mi-2β/NuRD or functionally associated TFs during the early stress response, and test whether these have functional consequences on and off chromatin. We ask how changes in the composition of the AP1 complex composition at target loci contribute to Mi-2β/NuRD complex displacement and return, and whether enduring changes in TF occupancy at the loci or PTMs contribute to epigenetic memory of the stress response. We examine how specificity is achieved by examining Mi-2β target loci that are regulated by different TFs that do not respond to stress signaling. In Aim 2, we investigate how histone modifications and higher order chromatin conformations contribute to induction, repression, and reactivation of stress response genes in keratinocytes. We test for changes in local histone modifications and TF recruitment at stress response genes and whether these contribute to the memory of the response, defined as accelerated kinetics and increased magnitude of the response upon rechallenge. We examine long-distance interactions between stress response enhancers, affiliated promoters, and CTCF architectural sites, whether these are already present prior to stress, if they actively form in response to it, and whether changes are maintained at some loci to alter activation thresholds as a mechanism of epigenetic memory. Targeted manipulation of Mi-2β/NuRD and AP1 complex occupancy at specific loci is employed to test their role in directing chromatin contacts and histone modifications at rest and during the response. We also examine the heterogeneity of chromatin accessibility among basal cell precursors, its heritability within clones, and the contribution of changing clonal composition of the basal layer to the evolution of the epigenetic memory of prior inflammatory insult.

摘要 有观点认为，位于人体与外界交界处的角质形成细胞已经发育。 专门的机制，以满足快速应对不断变化的一系列挑战的需求 和可逆的基因激活。我们过去的研究支持这样的假设，即信号信息与 皮肤环境侮辱在应激反应基因被抑制的增强子上迅速转化为染色质 导致他们暂时入职的变化。我们已经证明，Mi-2β/nuRD复合体设置了一个染色质 限制基因转录的环境，这些基因将由应激信号诱导角质形成细胞 它们保持沉默，但准备迅速激活。我们的研究强调了染色质重构体之间的动态切换 限制基因表达和支持转录激活的早期反应因子。其作用机制 研究了支持这种时态转换的因素及其对反应记忆的贡献。 在目标1中，我们研究了Mi-2β/nuRD是如何在动态平衡中被拴在应激反应基因座上的，在 压力响应，并在解决期间返回。我们测试Mi-2β/NuRD是否针对这些基因座 通过与转录因子的稳定联系，使用无偏见的方法和对AP1复合体的重点方法。 我们鉴定了Mi-2β/nuRD或功能相关的转录后修饰(PTM)在 早期的应激反应，并测试这些反应是否对染色质有功能影响。我们问 靶基因座AP1复合体组成的变化如何影响Mi-2β/NuRD复合体 流离失所和返回，以及Tf在这些地点的占有率或PTM的持久变化是否有助于 压力反应的表观遗传记忆。我们通过检测Mi-2β靶标来检验特异性是如何实现的 由不同的转录因子调控的基因座，这些基因对胁迫信号没有反应。 在目标2中，我们研究组蛋白修饰和更高阶染色质构象如何贡献 诱导、抑制和重新激活角质形成细胞中的应激反应基因。我们测试变化 在应激反应基因的局部组蛋白修饰和TF招募中，以及这些因素是否有助于 对反应的记忆，定义为加速的动力学和增加的反应幅度 重新挑战。我们研究了应激反应增强子、附属启动子、 以及CTCF建筑工地，如果它们积极地形成响应，这些工地在压力之前是否已经存在 以及是否在某些位点保持改变以改变激活阈值作为一种机制 表观遗传记忆。有针对性地操纵Mi-2β/NuRD和AP1复合体在特定位点的占有率 用来测试它们在静息和运动过程中引导染色质接触和组蛋白修饰的作用 回应。我们还检查了基底细胞前体细胞染色质可及性的异质性，其 无性系内的遗传力，以及基底层克隆组成变化对进化的贡献 对先前炎症性侮辱的表观遗传记忆。