Improving anti-tumor T cell immunity by targeting LDH-A functions beyond the Warburg effect

代谢重编程中的差异对于有效地印记不同的T细胞命运至关重要。以满足他们 为了满足生物能量需求，T效应细胞（TEFF）利用有氧糖酵解产生乳酸盐（瓦尔堡 效应），而T记忆细胞（TM）转换为脂肪酸氧化（FAO）。人们仍然不太清楚 TEFF向TM细胞的转变与同时的代谢重编程相关。目前还不清楚是否 糖酵解本身调节这种转变事件。乳酸脱氢酶-A（LDH-A）催化 在糖酵解的最后一步丙酮酸转化为乳酸，这是瓦尔堡效应的标志。LDH-A是 在人类癌症中上调并且与侵袭性肿瘤结果相关。相反， 肿瘤细胞中的LDH-A导致肿瘤发生减少和已建立肿瘤的消退。我们产生 LDH-A-/-小鼠和LDH-A-/-小鼠，其中LDH-A仅在T细胞中缺失， 研究靶向瓦尔堡效应的标志性步骤如何影响T细胞功能。抗原特异性cd8 + LDH-A-/-TEFF扩增迅速，向TCM和TSCM分化，并对抗原显示出强的反应性 介导的再激发。此外，肿瘤浸润性CD8 + LDH-A-/-T细胞保留了强大的线粒体功能， 在肿瘤微环境中并抑制肿瘤生长。代谢物示踪研究表明，LDH-A-/- CD8 + T细胞具有增强的葡萄糖通量，糖酵解、TCA循环和葡萄糖衍生的中间产物升高。 乙酰辅酶A，但减少使用谷氨酰胺的TCA回补。这种代谢偏好的改变 在胚胎干细胞（ES）细胞中发现，在那里它通过aKG依赖性 去甲基化并保持干性。此外，与ES细胞类似，LDH-A-/-CD8 + T细胞增加， 通过糖酵解衍生乙酰辅酶A介导的组蛋白乙酰化。这些代谢驱动的表观遗传变化 可能是LDH-A-/-细胞向具有干细胞性的TCM和TSCM快速分化的原因 功能.我们的研究结果支持了糖酵解在记忆T细胞中起关键作用的新假设。 通过产生丙酮酸进行分化，并且它是丙酮酸-乙酰辅酶A步骤而不是丙酮酸-乳酸步骤， 其有助于细胞身份的产生，并对转录和转录具有机械作用， T细胞的表观遗传状态。了解和概括这种代谢状态可能会提供一种新的方法 以产生用于癌症免疫治疗的有效抗原特异性TEFF和TM细胞。为了调查此事，我们将 追求以下具体目标，以确定： 1. LDH-A介导的代谢变化如何影响肿瘤特异性T细胞的分化程序 2. LDH-A靶向如何影响TM细胞分化的表观遗传调控。 3. LDH-A靶向如何影响肿瘤特异性T细胞的特性和功能

Divergence in the metabolic reprogramming is critical to effectively imprint distinct T cell fates. To meet their bioenergetic demands, T effector (TEFF) cells use aerobic glycolysis leading to lactate production (the Warburg effect), whereas T memory cells (TM) switch to fatty acid oxidation (FAO). It remains poorly understood how transition of TEFF to TM cells correlates with simultaneous metabolic reprogramming. It is also unclear whether glycolysis itself regulates such transition events. The lactate dehydrogenase-A (LDH-A) enzyme catalyzes the conversion of pyruvate to lactate in the last step of glycolysis, a hallmark of the Warburg effect. LDH-A is upregulated in human cancers and is associated with aggressive tumor outcomes. Conversely, inactivation of LDH-A in tumor cells results in decreased tumorigenesis and regression of established tumors. We generated LDH-Aflox/floxCD4-Cre (LDH-A-/-) and LDH-Aflox/flox (LDH-Acon) mice, in which LDH-A is deleted only in T cells, to study how targeting the hallmark step of the Warburg effect would affect T cell function. Antigen-specific CD8+ LDH-A-/- TEFF rapidly expanded, differentiated to TCM and TSCM and displayed potent response on antigen mediated re-challenge. Moreover, tumor-infiltrating CD8+ LDH-A-/- T cells retained robust mitochondrial function in the tumor microenvironment and inhibited tumor growth. Metabolite tracer studies revealed that LDH-A-/- CD8+ T cells had enhanced glucose flux, elevated intermediates of glycolysis, TCA cycle, and glucose-derived acetyl-coA but diminished usage of glutamine for TCA anaplerosis. This altered metabolic preference has been identified in embryonic stem cells (ES) cells, where it promotes histone/DNA demethylation by aKG-dependent demethylases and maintains stemness. Moreover, similarly to ES cells, LDH-A-/- CD8+ T cells had increased histone acetylation mediated via glycolysis-derived acetyl-CoA. These metabolism-driven epigenetic changes might be responsible for the rapid differentiation of LDH-A-/- cells to TCM and TSCM, which have stemness features. Our findings support the novel hypothesis that glycolysis has a key role on memory T cell differentiation by generating pyruvate and that it is the pyruvate-acetyl-CoA step not the pyruvate-lactate step, which contributes to the generation of cellular identity and has a mechanistic role on the transcriptional and epigenetic state of T cells. Understanding and recapitulating this metabolic state might provide a novel method to generate potent antigen-specific TEFF and TM cells for cancer immunotherapy. To investigate this, we will pursue the following specific aim to determine: 1. How LDH-A mediated metabolic changes affect the differentiation program of tumor-specific T cells. 2. How LDH-A targeting impacts the epigenetic regulation of TM cell differentiation. 3. How LDH-A targeting affects the properties and function of tumor-specific T cells.