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

代谢重新编程中的分歧对于有效地印记不同的T细胞命运至关重要。满足他们的需求 生物能量需求，T效应(Teff)细胞利用有氧糖酵解产生乳酸(Warburg 作用)，而T记忆细胞(TM)切换到脂肪酸氧化(FAO)。目前还不清楚它是如何 TEFF向TM细胞的转变与同时的代谢重编程相关。目前也不清楚是否 糖酵解本身调节这样的过渡事件。乳酸脱氢酶-A(LDH-A)酶催化 在糖酵解的最后一步，丙酮酸转化为乳酸，这是华宝效应的标志。LDH-A是 在人类癌症中上调，并与侵袭性肿瘤预后有关。相反，停用 肿瘤细胞中的LDH-A会减少肿瘤的发生和已建立的肿瘤的消退。我们生成了 LDH-Aflox/FloxCD4-CRE(LDH-A-/-)和LDH-Aflox/Flox(LDH-Acon)小鼠，其中LDH-A仅在T细胞中缺失， 研究以华宝效应的标志性步骤为靶点将如何影响T细胞功能。抗原特异性CD8 LDH-A-/-teff迅速扩增，分化为中药和中药，对抗原表现出较强的反应性 调解的重新挑战。此外，肿瘤浸润性CD8 LDH-A-/-T细胞保持了强大的线粒体功能 在肿瘤微环境中，抑制肿瘤生长。代谢物示踪研究显示LDH-A-/- CD8T细胞葡萄糖流量增加，糖酵解、TCA循环和葡萄糖衍生的中间产物增加 乙酰辅酶A，但减少了谷氨酰胺用于TCA逆转的使用。这种改变的新陈代谢偏好一直是 在胚胎干细胞(ES)中鉴定，在那里它通过依赖AKG促进组蛋白/DNA去甲基化 去甲基化并保持茎干。此外，与ES细胞类似，LDH-A-/-CD8 T细胞也有所增加 糖酵解衍生的乙酰辅酶A介导组蛋白乙酰化。这些新陈代谢驱动的表观遗传学变化 可能是LDH-A-/-细胞快速分化为有茎的中医和中医的原因 功能。我们的发现支持了糖酵解对记忆T细胞起关键作用的新假说 通过产生丙酮酸进行分化，这是丙酮酸-乙酰-辅酶A步骤而不是丙酮酸-乳酸步骤， 它有助于细胞身份的产生，并对转录和 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 产生强大的抗原特异性Teff和TM细胞，用于癌症免疫治疗。为了调查这件事，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靶向对肿瘤特异性T细胞特性和功能的影响。

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.