Nutrient-driven histone code determines exhausted CD8+ T cell fates [RNA-seq]

To investigate the role of ACSS2NLS in the regulation of CD8+ T cell responses in B16-GP33 tumor model Exhausted T cells (TEX) in cancer and chronic viral infections undergo metabolic and epigenetic remodeling, impairing protective capabilities. However, the impact of nutrient metabolism on epigenetic modifications that control TEX differentiation remains unclear. Our study reveals that TEX cells shift from acetate to citrate metabolism by downregulating acetyl-CoA synthetase 2 (ACSS2) while maintaining ATP-citrate lyase (ACLY) activity. This metabolic switch increases citrate-dependent histone acetylation, mediated by histone acetyltransferase KAT2A-ACLY interactions, at TEX signature-genes while reducing acetate-dependent histone acetylation, dependent on p300-ACSS2 complexes, at effector and memory T cell genes. Nuclear ACSS2 overexpression or ACLY inhibition prevents TEX differentiation and enhances tumor-specific T cell responses. These findings unveil a nutrient-driven histone code governing CD8+ T cell differentiation, with implications for metabolic- and epigenetic-based T cell therapies Overall design: RNA-seq gene expression profiling analysis for EV and ACSS2NLS TILs in B16-GP33 tumor at day 21 post tumor implantation

为探究ACSS2NLS在B16-GP33肿瘤模型中对CD8+ T细胞应答的调控作用。癌症与慢性病毒感染状态下的耗竭性T细胞（Exhausted T cells, TEX）会发生代谢与表观遗传重塑，进而削弱其免疫保护功能。然而，营养代谢对调控TEX分化的表观遗传修饰的影响仍不明确。本研究发现，TEX细胞通过下调乙酰辅酶A合成酶2（acetyl-CoA synthetase 2, ACSS2）的表达，同时维持ATP-柠檬酸裂解酶（ATP-citrate lyase, ACLY）的活性，实现从乙酸代谢向柠檬酸代谢的转变。这种代谢重塑会通过组蛋白乙酰转移酶KAT2A与ACLY的相互作用，增强TEX特征基因位点上依赖柠檬酸的组蛋白乙酰化水平；同时，依赖p300-ACSS2复合物的效应T细胞与记忆T细胞基因位点上的乙酸依赖性组蛋白乙酰化水平则会降低。核定位ACSS2过表达或ACLY抑制可阻断TEX分化，并增强肿瘤特异性T细胞应答。本研究结果揭示了一种由营养物质调控的、支配CD8+ T细胞分化的组蛋白密码，为基于代谢与表观遗传调控的T细胞疗法提供了理论参考。实验设计：对肿瘤植入后第21天的B16-GP33肿瘤组织中的空载体（empty vector, EV）与ACSS2NLS肿瘤浸润淋巴细胞（tumor-infiltrating lymphocytes, TILs）开展RNA测序基因表达谱分析。