Dissecting interplay between electrophilic stress and IkBz-driven inflammation

剖析亲电子应激与 IkBz 驱动的炎症之间的相互作用

• 批准号: 10556423
• 负责人: Monika Bambouskova
• 金额: $ 23.45万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10556423
• 关键词: 3' Untranslated Regions; 5' Untranslated Regions; Address; Affect; Animal Model; Anti-Inflammatory Agents; Autoimmune Diseases; Cell Line; Cells; Cellular Stress; Characteristics; Cysteine; Data; Dedications; Development; Down-Regulation; Elements; Epithelial Cells; Family; Foundations; Future; Genes; Genetic; Genetic Population Study; Genetic Transcription; Health; Human; IL17 gene; Immune; Immune response; In Vitro; Inflammation; Inflammatory; Interleukin-12; Interleukin-6; Investigation; Macrophage; Macrophage Activation; Mediating; Medical Genetics; Messenger RNA; Metabolic; Molecular; Mus; Nature; Pathology; Pathway interactions; Pneumococcal Infections; Production; Proteins; Psoriasis; RNA-Binding Proteins; Regulation; Regulatory Element; Role; Signal Transduction; Stress; Sulfhydryl Compounds; Susceptibility Gene; T-Lymphocyte; TNF gene; Toll-like receptors; Transcript; Translational Regulation; Translational Repression; Translations; Untranslated Regions; Up-Regulation; arm; biological adaptation to stress; candidate identification; cytokine; genetic approach; immune activation; immunoregulation; in vivo; member; mouse model; novel; novel therapeutic intervention; novel therapeutics; pharmacologic; programs; response; sensor; transcription factor; treatment strategy; trigger point

Abstract Electrophilic stress is a broad phenomenon caused by compounds that are reactive to thiol groups (-SH), such as cysteine residues within cellular proteins. We found that electrophilic stress response induced by dimethyl itaconate (DI), a derivative of the metabolite itaconate, mediates a strong, yet very selective inhibitory effect on the immune activation. In macrophages, DI treatment downregulates production of a subset of cytokines such as IL-6 or IL-12 but does not affect other cytokines such as TNF. We found that this selective effect occurs through inhibition of IκBζ, a transcription factor of the NF-κB family, which is commonly induced during immune activation. IκBζ selectively regulates inflammation in several important contexts: (1) in macrophages, IκBζ regulates the secondary transcriptional response to toll-like receptor stimulation and its deficiency leads to defective production of a subset of cytokines such as IL-6 and IL-12, but not TNF; (2) in epithelial cells, IκBζ is a primary regulator of the transcriptional response to IL-17; (3) in T-cells, it is an indispensable transcription factor facilitating Th17 polarization. Importantly, medical and population genetics studies have identified NFΚBIZ (the gene encoding IκBζ) as a major susceptibility locus for psoriasis, an IL-17-associated autoimmune condition. We have demonstrated that in vivo administration of DI completely ameliorates development of pathology in a mouse model of psoriasis. Therefore, a deeper understanding of the connection between IκBζ and electrophilic stress has the strong potential to uncover novel therapeutic avenues for treatment of autoimmune conditions, such as psoriasis. Moreover, although the major studied cellular response to electrophilic stress is the Keap1/Nrf2 pathway, we show that the effect of DI on IκBζ is independent of Nrf2. Our preliminary data suggest the existence of a discrete Nrf2-independent molecular pathway starting at Keap1 engagement by electrophiles and culminating in selective inhibition of IκBζ translation. Defining the mechanistic details of this pathway will deepen the general understanding of immune regulation and will provide novel therapeutic strategies in autoimmune diseases driven by the IκBζ-IL-17 axis. We aim to uncover key members and mechanisms of this pathway using the following converging strategies: 1) define the mechanism of IκBζ inhibition by electrophilic stress at the level of Keap1 and 2) define the mechanism of translational regulation of Nfkbiz mRNA in conditions of electrophilic stress. Completion of the proposed Aims will lay the foundation for future detailed in vitro and in vivo studies of the novel regulator/regulators of the IκBζ activation program. Ultimately, we aim to study the role of the novel IκBζ regulators identified by this proposal in the context of an inflammatory condition such as psoriasis, which will be the subject of a future R01 application.

摘要 亲电应力是由对巯基（-SH）具有反应性的化合物引起的广泛现象，例如 作为细胞蛋白质中的半胱氨酸残基。我们发现二甲基甲酰胺诱导的亲电应激反应 衣康酸盐（DI）是代谢产物衣康酸盐的衍生物，介导了一种强烈的，但非常选择性的抑制作用， 免疫激活。在巨噬细胞中，DI处理下调细胞因子亚群的产生， IL-6或IL-12，但不影响其他细胞因子如TNF。我们发现这种选择性效应是通过 抑制IκB β，一种NF-κB家族的转录因子，通常在免疫活化过程中诱导。 IκB β在几种重要的情况下选择性地调节炎症：（1）在巨噬细胞中，IκB β调节巨噬细胞的增殖。 对Toll样受体刺激的次级转录反应及其缺陷导致缺陷性生产 （2）在上皮细胞中，IκB β是细胞因子如IL-6和IL-12的主要调节因子，但不是TNF; 对IL-17的转录应答;（3）在T细胞中，它是促进Th 17的不可或缺的转录因子 极化重要的是，医学和群体遗传学研究已经确定了NF-Κ BBIZ（基因编码 IκB κ）作为银屑病（一种IL-17相关的自身免疫性疾病）的主要易感位点。我们有 证明了DI的体内给药完全改善了小鼠模型中病理学的发展 牛皮癣因此，更深入地了解IκB β和亲电应激之间的联系， 发现治疗自身免疫性疾病（如银屑病）的新治疗途径的强大潜力。 此外，虽然主要研究的细胞对亲电应激的反应是Keap 1/Nrf 2途径，我们 表明DI对IκB的影响与Nrf 2无关。我们的初步数据表明， 离散的Nrf 2独立的分子途径，起始于Keap 1与亲电体的结合， 最终选择性抑制IκB翻译。定义这一途径的机制细节将 加深了对免疫调节的一般理解，并将提供新的治疗策略， 由IκB β-IL-17轴驱动的自身免疫性疾病。我们的目标是揭示关键成员和机制， 该途径使用以下会聚策略：1）通过以下方法定义IκB抑制的机制： Keap水平的亲电应激1和2）定义Nfkbiz的翻译调节机制 mRNA在亲电应激条件下。完成拟议的目标将为今后的工作奠定基础。 IκB活化程序的新型调节剂的详细体外和体内研究。最终我们 目的是研究在炎症背景下，该提议确定的新型IκB调节剂的作用。 条件，如牛皮癣，这将是未来的R 01应用的主题。