Notch1调控Foxp3+Treg细胞功能参与慢性鼻-鼻窦炎伴鼻息肉中嗜酸性粒细胞浸润的机制研究

Recent studies pointed out that the decreased Foxp3+Treg cell-mediated suppression on differentiation of Th2 cells from effector T cells that leads to the increased cytokines of Th2 cells play an important role in mucosa eosinophil (Eos) recruitment. Notch1 pathway activates Foxp3+Treg cell-mediated suppression on effector T cells. Our previous studies found that the downregulation of Notch1 was associated with the decreased Foxp3+Treg cells and the increased Th2 cytokines in mucosa of CRSwNP, respectively. And all these three factors were found to be associated with eosinophil infiltration. It was implied that downregulated Notch1 participates in decreasing the Foxp3+Treg suppression on the differentiation of Th2 cells from effector T cells, as a result, the upregulated Th2 cytokines further contributes to eosinophil infiltration. This study intends to evaluate that the decreased Foxp3+Treg cells, decreased Notch1 and increased Th2 cytokines are associated with eosinophil infiltration in nasal mucosa, respectively, and intends to approve the positive correlation between Foxp3+Treg cells and Notch1. Then, CD4+CD25- T cells and CD4+CD25+ T cells from the spleen of BALB/c mice were co-cultured, to show that the inhibition of Notch1 lead to remove the Foxp3+Treg suppression on Th2 cells differentiation through blocking Notch1 signaling with anti-Notch1 Ab. Meanwhile, the supernatants of all cultured cells were tested for their effects on the growth and transfer of Eos. Finally, we intend to show that Foxp3+Treg cells with activated Notch1 pathway would enhance Foxp3+Treg suppressive function to reduce the eosinophil infiltration by decreasing Th2 cytokines. This is the first study on that Notch signal pathway regulates Foxp3+Treg cells in Eos-CRSwNP, and will be helpful to gain more insight into explore new treatment for Eos-CRSwNP.

Foxp3+Treg细胞下调引起Th2细胞因子增高在嗜酸性粒细胞浸润型慢性鼻-鼻窦炎伴鼻息肉（Eos-CRSwNP）发病过程中起重要作用。然鼻息肉中该细胞表达下调原因不明。Notch1通路参与上调Foxp3表达，我们研究发现：鼻息肉中Notch1下调，与Foxp3+Treg细胞表达正相关，与Th2细胞因子表达和Eos浸润负相关，提示：Notch1下调可能解除Treg细胞对Th2细胞分化的抑制、促Eos浸润。本项目拟通过临床样本检测明确Notch1表达与Foxp3+Treg、Th2细胞功能及Eos浸润相关；采用细胞共培养证实Notch1抗体封闭可下调Foxp3、促Th2细胞分化；构建动物模型验证Notch1活化的Treg细胞回输可减轻鼻黏膜局部Th2型炎症反应及Eos浸润程度；首次探讨Notch1调控Foxp3+Treg细胞功能参与Eos-CRSwNP的发病机制，为寻求新治疗方法提供理论依据

Foxp3+Treg细胞下调引起Th2细胞因子增高在嗜酸性粒细胞浸润型慢性鼻-鼻窦炎伴鼻息肉（Eos-CRSwNP）发病过程中起重要作用。然鼻息肉中该细胞表达下调原因不明。该项目通过采集134 例CRSwNP, 67 例CRSsNP及 62例对照的组织及部分患者外周血进行qRT-PCR、western blot，流式细胞分析、免疫荧光等方法分析，发现：.CRSwNP组患者鼻黏膜局部的Foxp3的mRNA及蛋白水平下降，CD4+CD25+Foxp3+Treg，CD4+CD25+CD127lowTreg表达仅在CRSwNP患者鼻黏膜局部下调明显；CRSwNP中，尤其是嗜酸性粒细胞浸润型的CRSwNP中的Th2及 Th17炎症因子表达增高显著，Tc2和Tc17的增高也非常显著，Tc17与CRSwNP组织重塑形成密切相关，相关研究已经发表在（Front. Immunol.，2018，IF=5.1 ）；CRSwNP鼻黏膜局部嗜酸性粒细胞阳离子蛋白ECP的表达水平增高显著，Treg表达下降，二者呈现相反趋势；Notch通路表达在嗜酸性粒细胞浸润型CRSwNP中下调明显；通过体外实验明确抑制Notch通路后，CD4+CD25+Treg对CD4+CD25-T产生IL-4的抑制能力增强。与预期结果相反。提示Treg可以抑制Th2细胞因子的分泌；同时体外将Naïve T诱导成Th2的过程中，添加Treg可以抑制Naïve T诱导成Th2，减少IL-4的分泌。Notch通路可能不是直接作用于Treg，抑制foxp3表达，而是直接抑制CD4+CD25-T分泌IL-4。具体的机制有待进一步的探索；最后通过构建Eos浸润的慢性鼻窦炎小鼠（ECRS）模型，明确ECRS小鼠鼻黏膜局部存在Th2炎症反应。iTreg尾静脉回输可减轻鼻黏膜局部Th2炎症，减少Eos浸润。