The Feinstein Institute for Medical Research, Center for Autoimmune, Musculoskeletal and Hematopoietic Diseases, 350 Community Dr., Manhasset, NY 11030, USA.
Hoffmann-La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, USA.
Sci Adv. 2020 May 15;6(20):eaay1057. doi: 10.1126/sciadv.aay1057. eCollection 2020 May.
The transcription factor interferon regulatory factor 5 (IRF5) plays essential roles in pathogen-induced immunity downstream of Toll-, nucleotide-binding oligomerization domain-, and retinoic acid-inducible gene I-like receptors and is an autoimmune susceptibility gene. Normally, inactive in the cytoplasm, upon stimulation, IRF5 undergoes posttranslational modification(s), homodimerization, and nuclear translocation, where dimers mediate proinflammatory gene transcription. Here, we report the rational design of cell-penetrating peptides (CPPs) that disrupt IRF5 homodimerization. Biochemical and imaging analysis shows that IRF5-CPPs are cell permeable, noncytotoxic, and directly bind to endogenous IRF5. IRF5-CPPs were selective and afforded cell type- and species-specific inhibition. In plasmacytoid dendritic cells, inhibition of IRF5-mediated interferon-α production corresponded to a dose-dependent reduction in nuclear phosphorylated IRF5 [p(Ser)IRF5], with no effect on pIRF5 levels. These data support that IRF5-CPPs function downstream of phosphorylation. Together, data support the utility of IRF5-CPPs as novel tools to probe IRF5 activation and function in disease.
转录因子干扰素调节因子 5（IRF5）在 Toll、核苷酸结合寡聚化结构域和视黄酸诱导基因 I 样受体诱导的病原体免疫中发挥重要作用，是自身免疫易感性基因。正常情况下，IRF5 在细胞质中处于非活性状态，受到刺激后，IRF5 会发生翻译后修饰、同源二聚化和核易位，二聚体介导促炎基因转录。在这里，我们报告了一种细胞穿透肽（CPP）的合理设计，该 CPP 可破坏 IRF5 同源二聚体。生化和成像分析表明，IRF5-CPP 可穿透细胞，无细胞毒性，并可直接与内源性 IRF5 结合。IRF5-CPP 具有选择性，可提供细胞类型和物种特异性抑制。在浆细胞样树突状细胞中，IRF5 介导的干扰素-α产生的抑制与核磷酸化 IRF5[p(Ser)IRF5]的剂量依赖性降低相对应，对 pIRF5 水平没有影响。这些数据支持 IRF5-CPP 作为一种新工具，在疾病中可用于研究 IRF5 激活和功能。
