Zagorski Joseph W, Turley Alexandra E, Freeborn Robert A, VanDenBerg Kelly R, Dover Heather E, Kardell Brian R, Liby Karen T, Rockwell Cheryl E
Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States; Cell and Molecular Biology Program, Michigan State University, East Lansing, MI 48824, United States.
Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States.
Biochem Pharmacol. 2018 Jan;147:67-76. doi: 10.1016/j.bcp.2017.11.005. Epub 2017 Nov 15.
We previously demonstrated that activation of the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) promotes CD4+ Th2 differentiation. In the current study, we assessed the role of Nrf2 in early events following T cell activation. The Nrf2 activators, tBHQ (tert-butylhydroquinone) and CDDO-Im (the imidazolide derivative of the triterpenoid CDDO), were used in conjunction with splenocytes derived from wild-type and Nrf2-null mice to distinguish between Nrf2-specific and off-target effects. CDDO-Im inhibited early IFNγ production in a largely Nrf2-dependent manner. In contrast, tBHQ and CDDO-Im had little effect on expression of CD25 or CD69. Furthermore, tBHQ inhibited GM-CSF and IL-2 production in both wild-type and Nrf2-null T cells, suggesting this effect is Nrf2-independent. Conversely, CDDO-Im caused a concentration-dependent increase in IL-2 secretion in wild-type, but not Nrf2-null, splenocytes, suggesting that Nrf2 promotes IL-2 production. Interestingly, both compounds inhibit NFκB DNA binding, where the suppression by tBHQ is Nrf2-independent and CDDO-Im is Nrf2-dependent. Surprisingly, as compared to wild-type splenocytes, Nrf2-null splenocytes showed lower nuclear accumulation of c-Jun, a member of the AP-1 family of transcription factors, which have been shown to drive multiple immune genes, including IL-2. Both Nrf2 activators caused a Nrf2-dependent trend toward increased nuclear accumulation of c-Jun. These data suggest that modulation of cytokine secretion by tBHQ likely involves multiple pathways, including AP-1, NFκB, and Nrf2. Overall, the data suggest that Nrf2 activation inhibits secretion of the Th1 cytokine IFNγ, and increases early production of IL-2, which has been shown to promote Th2 differentiation, and may support the later occurrence of Th2 polarization.
我们之前证明转录因子核因子红细胞2相关因子2（Nrf2）的激活促进CD4 + Th2分化。在当前研究中，我们评估了Nrf2在T细胞激活后早期事件中的作用。Nrf2激活剂叔丁基对苯二酚（tBHQ）和齐墩果酸咪唑化物（CDDO-Im，三萜类化合物CDDO的咪唑化物衍生物）与野生型和Nrf2基因敲除小鼠的脾细胞联合使用，以区分Nrf2特异性作用和脱靶效应。CDDO-Im在很大程度上以Nrf2依赖的方式抑制早期IFNγ产生。相比之下，tBHQ和CDDO-Im对CD25或CD69的表达几乎没有影响。此外，tBHQ抑制野生型和Nrf2基因敲除T细胞中GM-CSF和IL-2的产生，表明这种作用不依赖于Nrf2。相反，CDDO-Im导致野生型脾细胞（而非Nrf2基因敲除脾细胞）中IL-2分泌呈浓度依赖性增加，表明Nrf2促进IL-2产生。有趣的是，两种化合物均抑制NFκB与DNA结合，其中tBHQ的抑制作用不依赖于Nrf2，而CDDO-Im的抑制作用依赖于Nrf2。令人惊讶的是，与野生型脾细胞相比，Nrf2基因敲除脾细胞中c-Jun（AP-1转录因子家族成员，已证明其可驱动包括IL-2在内的多种免疫基因）的核内积累较低。两种Nrf2激活剂均导致c-Jun核内积累呈Nrf2依赖的增加趋势。这些数据表明，tBHQ对细胞因子分泌的调节可能涉及多种途径，包括AP-1、NFκB和Nrf2。总体而言，数据表明Nrf2激活抑制Th1细胞因子IFNγ的分泌，并增加IL-2的早期产生，IL-2已被证明可促进Th2分化，并可能支持Th2极化的后期发生。
