Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, 210009, China.
Cell Death Dis. 2018 Feb 15;9(3):258. doi: 10.1038/s41419-018-0297-3.
Norisoboldine (NOR), a natural aryl hydrocarbon receptor (AhR) agonist, has been demonstrated to attenuate ulcerative colitis (UC) and induce the generation of Treg cells. Under UC condition, hypoxia widely exists in colonic mucosa, and secondary changes of microRNAs (miRs) expressions and glycolysis contribute to Treg differentiation. At present, we worked for exploring the deep mechanisms for NOR-promoted Treg differentiation in hypoxia and its subsequent anti-UC action from the angle of AhR/miR or AhR/glycolysis axis. Results showed that NOR promoted Treg differentiation in hypoxia and the effect was stronger relative to normoxia. It activated AhR in CD4 T cells under hypoxic microenvironment; CH223191 (a specific AhR antagonist) and siAhR-3 abolished NOR-promoted Treg differentiation. Furthermore, the progress of glycolysis, levels of Glut1 and HK2, and expression of miR-31 rather than miR-219 and miR-490 in CD4 T cells were downregulated by NOR treatment under hypoxic microenvironment. However, HK2 plasmid but not miR-31 mimic significantly interfered NOR-enhanced Treg polarization. In addition, NOR reduced NAD and SIRT1 levels, facilitated the ubiquitin-proteasomal degradation of SUV39H1 protein, and inhibited the enrichment of H3K9me3 at -1, 201 to -1,500 region of Foxp3 promoter in CD4 T cells under hypoxic microenvironment, which was weakened by HK2 plasmid, CH223191, and siAhR-3. Finally, the correlation between NOR-mediated activation of AhR, repression of glycolysis, regulation of NAD/SIRT1/SUV39H1/H3K9me3 signals, induction of Treg cells, and remission of colitis was confirmed in mice with DSS-induced colitis by using CH223191 and HK2 plasmid. In conclusion, NOR promoted Treg differentiation and then alleviated the development of colitis by regulating AhR/glycolysis axis and subsequent NAD/SIRT1/SUV39H1/H3K9me3 signaling pathway.
去异波尔定（NOR）是一种天然芳香烃受体（AhR）激动剂，已被证明可减轻溃疡性结肠炎（UC）并诱导 Treg 细胞的产生。在 UC 情况下，结肠黏膜中广泛存在缺氧，miR 表达和糖酵解的继发变化有助于 Treg 分化。目前，我们从 AhR/miR 或 AhR/糖酵解轴的角度探索了 NOR 促进缺氧下 Treg 分化及其随后抗 UC 作用的深层机制。结果表明，NOR 促进了缺氧下 Treg 的分化，其效果强于常氧。它在缺氧微环境下激活 CD4 T 细胞中的 AhR；CH223191（一种特异性 AhR 拮抗剂）和 siAhR-3 消除了 NOR 促进的 Treg 分化。此外，NOR 处理可下调缺氧微环境下 CD4 T 细胞中糖酵解的进展、Glut1 和 HK2 的水平以及 miR-31 的表达，而 miR-219 和 miR-490 的表达则不受影响。然而，HK2 质粒而非 miR-31 模拟物显著干扰了 NOR 增强的 Treg 极化。此外，NOR 降低了 NAD 和 SIRT1 水平，促进了 SUV39H1 蛋白的泛素-蛋白酶体降解，并抑制了缺氧微环境下 CD4 T 细胞中 Foxp3 启动子-1、201 至-1、500 区域的 H3K9me3 富集，该作用可被 HK2 质粒、CH223191 和 siAhR-3 减弱。最后，通过使用 CH223191 和 HK2 质粒，在 DSS 诱导的结肠炎小鼠中证实了 NOR 介导的 AhR 激活、糖酵解抑制、NAD/SIRT1/SUV39H1/H3K9me3 信号调节、Treg 细胞诱导和结肠炎缓解之间的相关性。综上所述，NOR 通过调节 AhR/糖酵解轴及其随后的 NAD/SIRT1/SUV39H1/H3K9me3 信号通路，促进 Treg 分化，从而缓解结肠炎的发展。
