Department of Clinical Laboratory, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, Xinjiang, China; Xinjiang Institute of Pediatrics, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi 830001, Xinjiang, China.
Clinical Medicine Research Center, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi 830001, Xinjiang, China.
Int Immunopharmacol. 2018 Jan;54:24-32. doi: 10.1016/j.intimp.2017.10.026. Epub 2017 Oct 28.
Th1/Th2 imbalance to Th2 is of significance in the peripheral immune responses in Tuberculosis (TB) development. However, the mechanisms for Th1/Th2 imbalance are still not well determined. Notch signaling pathway is involved in the peripheral T cell activation and effector cell differentiation. However, whether it affects Th1/Th2 imbalance in TB patients is still not known. Here, we used γ-secretase inhibitor (DAPT) to treat the peripheral blood mononuclear cells (PBMCs) from healthy people or individuals with latent or active TB infection in vitro, respectively. Then, the Th1/Th2 ratios were determined by flow cytometry, and cytokines of IFN-γ, IL-4, IL-10 in the culture supernatant were measured by CBA method. The Notch signal pathway associated proteins Hes1, GATA3 and T-bet were quantitated by real-time PCR or immunoblotting. Our results showed that DAPT effectively inhibited the protein level of Hes1. In TB patients, the Th2 ratio increased in the PBMCs, alone with the high expression of GATA3 and IL-4, resulting in the high ratios of Th2/Th1 and GATA3/T-bet in TB patients. However, Th2 cells ratio decreased after blocking the Notch signaling pathway by DAPT and the Th2/Th1 ratio in TB patients were DAPT dose-dependent, accompanied by the decrease of IL-4 and GATA3. But, its influence on Th1 ratio and Th1 related T-bet and IFN-γ levels were not significant. In conclusion, our results suggest that blocking Notch signaling by DAPT could inhibit Th2 responses and restore Th1/Th2 imbalance in TB patients.
Th1/Th2 失衡向 Th2 倾斜在结核病（TB）发展的外周免疫反应中具有重要意义。然而，Th1/Th2 失衡的机制仍未得到很好的确定。Notch 信号通路参与外周 T 细胞的激活和效应细胞分化。然而，它是否会影响 TB 患者的 Th1/Th2 失衡尚不清楚。在这里，我们分别使用γ-分泌酶抑制剂（DAPT）在体外处理健康人或潜伏或活动性 TB 感染个体的外周血单个核细胞（PBMC），然后通过流式细胞术测定 Th1/Th2 比值，通过 CBA 法测定培养上清液中 IFN-γ、IL-4、IL-10 的细胞因子。通过实时 PCR 或免疫印迹法定量 Notch 信号通路相关蛋白 Hes1、GATA3 和 T-bet。我们的结果表明，DAPT 可有效抑制 Hes1 的蛋白水平。在 TB 患者中，PBMC 中的 Th2 比例增加，同时 GATA3 和 IL-4 表达升高，导致 TB 患者 Th2/Th1 和 GATA3/T-bet 比值升高。然而，通过 DAPT 阻断 Notch 信号通路后，Th2 细胞比例下降，TB 患者的 Th2/Th1 比值呈 DAPT 剂量依赖性，同时 IL-4 和 GATA3 减少。但是，它对 Th1 比例和 Th1 相关的 T-bet 和 IFN-γ 水平的影响并不显著。总之，我们的结果表明，DAPT 通过阻断 Notch 信号通路可以抑制 Th2 反应并恢复 TB 患者的 Th1/Th2 失衡。
