VPS72 controls Treg cell stability and adaptation to tumor microenvironment

摘要 众所周知，肿瘤微环境内的免疫抑制生态位 (TME)与肿瘤免疫逃逸和进展有关，其中调节性T细胞(Tregs) 发挥重要作用。尽管在鉴定转录和转录因子方面取得了一些进展 TME中Treg功能调控的表观遗传事件，我们的 了解详细的表观遗传网络介导Treg的生存、扩张和 TME诱导的免疫抑制功能增强。空泡蛋白分类72同系物 (VPS72)，一种组蛋白伴侣蛋白，识别组蛋白H2A.Z并将其交换为标准组蛋白 H_2A，已在体外研究中表明，它调节基因转录，特别是与 线粒体通过染色质重塑代谢，尽管体内的生物学功能 VPS72的致病原因尚不清楚。我们的初步研究显示，该基因的高表达和阳性 TME内Tregs中VPS72和Foxp3的相关性有趣的是，我们的Treg专属 VPS72 KO和H2 A.Z KO小鼠模型显示胸腺Treg发育正常，但 严重中断了外围设备Treg的维护和功能。这些结果导致我们的 核心假设VPS72是一种关键的表观遗传因子，可由TME因子诱导 并通过TME中Treg的H_2A.Z染色质重塑增强Treg的稳定性和功能。 在拟议的研究中，我们使用了Treg特异的结构性和诱导性基因缺失 建立小鼠模型以确定VPS72和H2 AZ在外周Treg细胞维持中的作用， 在癌症中的稳定性和功能。结合使用scRNA-seq、scATAC-seq和Cut&Run- SEQ多组分析，我们将勾勒出表观遗传策略和详细的分子 VPS72调控Treg动态平衡和功能的机制和信号通路。 在移植瘤和自发性黑色素瘤模型中，我们将评估其抗肿瘤作用 VPS72和H_2AZ抑制。此外，TME影响因素及其相关的分子机制 在上调Tme中Tregs的VPS72表达的同时，也将对其进行研究。调查结果： 拟议的研究不仅将增进我们对Treg生物学的了解，还将促进 开发更有效的基于Treg的癌症治疗干预策略。

Abstract It became well known that the immune suppressive niche inside the tumor microenvironment (TME) accounts for tumor immune escape and progression, in which the regulatory T cells (Tregs) play an important role. Although some progress has been made in identifying transcriptional and epigenetic events in Treg functional regulation in TME, a fundamental gap remains in our understanding the detailed epigenetic networks mediating Treg survival, expansion and enhanced immune suppressive function induced by TME. Vacuolar protein sorting 72 homolog (VPS72), a histone chaperone that recognizes and exchanges histone H2A.Z for standard histone H2A, has been shown in in vitro studies that regulate gene transcriptions especially related in mitochondrial metabolism through chromatin remodeling, although the in vivo biological function of VPS72 remains unknown. Our preliminary studies revealed the higher expression and positive correlation between VPS72 and Foxp3 in the Tregs inside the TME. Intriguingly, our Treg-specific VPS72 KO and H2A.Z KO mouse models showed normal thymic Treg development, but dramatically interrupted peripheral Treg maintenance and function. These results led to our central hypothesis that VPS72 is a critical epigenetic factor that can be induced by TME factors and enhance Treg stability and function through H2A.Z chromatin remodeling of Treg in the TME. In the proposed studies, we are using Treg-specific constitutive and inducible gene deletion mouse models to determine the role of VPS72 and H2AZ in peripheral Treg cell maintenance, stability and function in the cancer. Using combined scRNA-seq, scATAC-seq, and CUT & RUN- seq multi-omic analysis, we will delineate the epigenetic strategies and detailed molecular mechanisms and signaling pathways VPS72 used in controlling Treg homeostasis and function. In transplant and spontaneous melanoma tumor models, we will evaluate the anti-tumor effects of VPS72 and H2AZ suppression. Furthermore, TME factors and related molecular mechanisms in upregulating VPS72 expression of Tregs in TME will be also investigated. Results from the proposed study will not only enhance our understanding of Treg biology but will also facilitate the development of more efficient Treg-based intervention strategies for cancer treatment.