TIPE2纠正Foxp3+ Treg免疫稳态失衡在急性GVHD发病机制中的作用研究

Acute graft-versus-host disease (GVHD) is an important factor affecting the effect of allogeneic hematopoietic stem cell transplantation. Studies have confirmed that the imbalance of Foxp3+ Treg immune homeostasis plays an important role in the development of acute GVHD. Our study revealed that Gal-9 was involved in the pathogenesis of acute GVHD by regulating the immune homeostasis of Foxp3+ Treg. However, the exact mechanism of the upstream regulation of Gal-9 in acute GVHD has not been elucidated. Our previous studies have identified TIPE2 as a new regulatory molecule of Gal-9. Nevertheless, the role of TIPE2, an important molecular regulation of immune homeostasis, in acute GVHD has not been reported. Therefore, we intend to explore the relevance of TIPE2 with acute GVHD at first and then from two angles: in vivo and in vitro experiments and two aspects: phenomenon and mechanism, we investigate whether TIPE2 could regulate Foxp3+ Treg immune homeostasis through mediating Gal-9, resulting in its modulation on the development and progression of acute GVHD. If successful, it might provide more safe prevention strategies and new therapeutic targets for acute GVHD.

急性移植物抗宿主病(graft-versus-host disease, GVHD)是影响异基因造血干细胞移植疗效的重要因素之一，研究证实Foxp3+ Treg免疫稳态失衡是急性GVHD发生的重要环节，我们的研究提示Gal-9通过调控Foxp3+ Treg的免疫稳态参与急性GVHD发生。但Gal-9上游调控在急性GVHD发生中的机制尚未阐明。我们前期研究发现了Gal-9的新调控分子TIPE2；作为调控免疫稳态的重要分子，TIPE2在急性GVHD中的研究尚未见报道。因此，本课题创新性地从探讨TIPE2与急性GVHD发生的相关性出发，通过体外实验及体内实验，从现象观察及机制探索两个方面探究TIPE2是否通过调控Gal-9影响Foxp3+ Treg免疫稳态从而在急性GVHD发生发展中起重要作用。如获成功，有望为急性GVHD提供更安全的防治策略及治疗靶点。

急性移植物抗宿主病(graft-versus-host disease, GVHD)是影响异基因造血干细胞移植疗效的重要因素之一，研究证实Foxp3+ Treg免疫稳态失衡是急性GVHD发生的重要环节，我们的研究提示Gal-9通过调控Foxp3+ Treg的免疫稳态参与急性GVHD发生。但Gal-9上游调控在急性GVHD发生中的机制尚未阐明。我们前期研究发现了Gal-9的新调控分子TIPE2；作为调控免疫稳态的重要分子，TIPE2在急性GVHD中的研究尚未见报道。按照课题计划，本研究完成了以下工作。(1) 获取急性GVHD患者治疗前后的外周血血浆及单个核细胞等样本，通过ELISA、q-PCR及western blot等方法，检测TIPE2在急性GVHD患者治疗前后的指标变化，进一步明确TIPE2与急性GVHD严重程度的相关性；以及TIPE2对Foxp3+ Treg免疫稳态的正向调控作用。(2) 构建急性GVHD动物模型，应用抗体封闭的方法，分别封闭TIPE2及Gal-9蛋白分子的功能。发现在小鼠急性GVHD模型中，TIPE2和Gal-9均可促进Foxp3+ Treg分泌、上调T细胞活化程度，减轻急性GVHD严重程度。(3) 利用慢病毒系统上调或下调TIPE2基因的表达，通过western blot检测Gal-9蛋白表达变化，表明TIPE2对Gal-9有直接正向调控作用；在Foxp3+ Treg中过表达TIPE2，同时基因沉默Gal-9，发现TIPE2调控Foxp3+ Treg免疫稳态依赖Gal-9基因表达。研究意义：提示TIPE2通过调控Gal-9参与急性GVHD的发生发展，同时TIPE2未来有望作为急性GVHD防治提供新的作用靶点。