Dissecting interplay between electrophilic stress and IkBz-driven inflammation

摘要 亲电应力是由对硫醇基 (-SH) 具有反应性的化合物引起的一种广泛现象，例如 作为细胞蛋白质内的半胱氨酸残基。我们发现二甲基诱导的亲电应激反应 衣康酸 (DI) 是代谢物衣康酸的衍生物，对 免疫激活。在巨噬细胞中，DI 治疗会下调细胞因子子集的产生，例如 IL-6 或 IL-12 但不影响其他细胞因子，例如 TNF。我们发现这种选择性效应是通过 抑制 IκB z（NF-κB 家族的转录因子），通常在免疫激活过程中诱导。 IκBz 在几个重要的环境中选择性地调节炎症：(1) 在巨噬细胞中，IκBz 调节 对 Toll 样受体刺激的次级转录反应及其缺陷导致生产缺陷 细胞因子的子集，例如 IL-6 和 IL-12，但不包括 TNF； (2) 在上皮细胞中，IκBδ 是 对 IL-17 的转录反应； (3)在T细胞中，它是促进Th17不可缺少的转录因子 极化。重要的是，医学和群体遗传学研究已经确定了 NFΚBIZ（编码基因） IκB z）作为银屑病（一种 IL-17 相关自身免疫性疾病）的主要易感位点。我们有 证明体内给予 DI 可以完全改善小鼠模型的病理学发展 牛皮癣。因此，更深入地了解 IκB z 与亲电应力之间的联系具有重要意义。 发现治疗自身免疫性疾病（例如牛皮癣）的新治疗途径的巨大潜力。 此外，虽然主要研究的细胞对亲电应激的反应是 Keap1/Nrf2 途径，但我们 结果表明 DI 对 IκB z 的影响与 Nrf2 无关。我们的初步数据表明存在 不依赖于 Nrf2 的离散分子通路始于 Keap1 与亲电子试剂的结合 最终选择性抑制 IκB z 翻译。定义该途径的机制细节将 加深对免疫调节的一般理解，并将提供新的治疗策略 由 IκB z-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 该通路使用以下聚合策略：1) 通过以下方式定义 IκB z 抑制机制： Keap1 和 2 水平的亲电应激定义了 Nfkbiz 翻译调控机制 亲电应激条件下的 mRNA。完成既定目标，为未来打下基础 IκB z 激活程序的新型调节剂/调节剂的详细体外和体内研究。最终，我们 旨在研究该提案确定的新型 IκB z 调节剂在炎症背景下的作用 银屑病等疾病将成为未来 R01 应用的主题。

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.