Post-Translational Control of TET Function in Lymphoma

淋巴瘤 TET 功能的翻译后控制

• 批准号: 10512054
• 负责人: Ricardo C Aguiar
• 金额: --
• 依托单位: SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10512054
• 关键词: Acetyl Coenzyme A; Acetylation; Area; B-Cell Lymphomas; Balkans; Binding; Biology; Blood Cells; Cell Line; Chemical Exposure; DNA; DNA Methylation; Data; Development; Diagnosis; Distal; Early Diagnosis; Enhancers; Enzymes; Epigenetic Process; Exercise; Gene Expression; Gene Expression Profile; Generations; Genes; Genetic; Genetic Transcription; Genomics; Glioma; Growth; Hexosamines; Histones; Human; Hyperactivity; In Vitro; Incidence; Infectious Agent; Leukemic Cell; Link; Location; Lymphoma; Lymphomagenesis; Malignant Neoplasms; Maps; Mediating; Metabolic; Metabolism; Methylation; Military Personnel; Mitochondria; Mixed Function Oxygenases; Modeling; Mus; Myeloid Cells; Nature; Nuclear; O-GlcNAc transferase; Oncogenic; Organelles; Outcome; Output; Oxidoreductase; Pathology; Pathway interactions; Physiology; Play; Population; Post-Translational Protein Processing; Process; Proliferating; Reporter; Reporting; Research; Resolution; Risk; Role; S-Adenosylhomocysteine; S-Adenosylmethionine; Signal Transduction; Stem Cell Development; Testing; Tetanus Helper Peptide; Therapeutic; Tumor Suppressor Proteins; Veterans; Vietnam; Western World; Work; alpha ketoglutarate; base; cancer type; chromatin immunoprecipitation; defined contribution; demethylation; in vitro Model; in vivo; large cell Diffuse non-Hodgkin' s lymphoma; mitochondrial metabolism; mouse model; novel; novel marker; oxidation; programs; promoter; segregation; stem cell biology; transcription factor; tumor

TET DNA hydroxylases are alpha-ketoglutarate (αKG)-dependent enzymes that catalyze the oxidation of 5mC to 5-hydroxymethylcytosine (5hmC), thus promoting DNA demethylation. Mapping of 5hmC marks at single base resolution demonstrated that the main role of TET enzymes is to maintain gene enhancers hypomethylated and active. Enhancers are genomic areas to which transcription factors bind to modulate gene expression programs. Hyperactive clusters of enhancers that are densely occupied by transcriptional factors are termed super- enhancers and are typically found in cancer. Like promoters, enhancers/super-enhancers are regulated by their DNA methylation status, a process that often goes awry in cancer. Thus, given that active enhancers and super- enhancers are oncogenic in nature, and that TET enzymes maintain them hypomethylated and active, we postulate that increased TET activity may itself be oncogenic. Mitochondria function as signaling organelles by generating substrates that fuel epigenetic changes, including for example acetylation and methylation of DNA and histones, respectively. Recently, we and others described a subtler interplay between mitochondria and epigenetics, wherein the levels of the intermediate metabolites αKG and 2-hydroxyglutarate were found to modulate the activity of TET enzymes, thus controlling DNA methylation. These findings led us to hypothesize that intermediary metabolism plays as an important role in the control of DNA methylation. Specifically, we posited that the mitochondrial enzymes D-2- and L-2-hydroxyglutarate dehydrogenase (D2HGDH and L2HGDH), which catalyze the interconversion of 2-HG to αKG, are integral to the cross talk between mitochondrial metabolism, TET function and super-enhancer demethylation/activation. To expand on this initial concept, we sought to identify upstream signals that regulate D2HGDH and L2HGDH expression and, consequently, influence TET function and enhancer methylation/activity. Using reporter and ChIP assays, inducible cell lines and mouse models, we recently reported that MYC transcriptionally activates D2HGDH and L2HGDH and, in a D2HGDH/L2HGDH/αKG-dependent manner, induces TET function leading to DNA demethylation in vitro and in vivo. Remarkably, we discovered that the MYC/D2-L2HGDH/αKG axis also promotes the nuclear accumulation of TET1, TET2 and TET3, in association with enhanced O-GlcNAcylation, a post-translational modification executed by another mitochondrial enzyme, O-GlcNAc transferase (OGT). Further, we preliminarily showed that in in diffuse large B cell lymphoma (DLBCL), MYC levels associated with enhancer methylation and target gene expression. Together, these data uncovered a novel mitochondrial signaling axis which includes MYC at the proximal point, D2/L2HGDH and OGT at the center, and, distally, TET activity and subcellular location. In this proposal, we will use human B cell lymphoma models in vitro and in vivo, to test the overarching hypothesis that intermediary metabolism, in part due to MYC activity, induces TET function, maintains oncogenic enhancers/super-enhancers hypomethylated and active and promote cancer. Our specific aims are: AIM 1) Determine the mechanistic basis for the increased O-GlcNAcylation mediated by the MYC-D2/L2HGDH-αKG axis and its role in promoting TET nuclear localization and enhancer activation. AIM 2) Define the contribution of the TET activation to MYC-driven lymphomagenesis AIM 3) Characterize the MYC- driven map of 5hmC marks and super-enhancer activation in B cell lymphoma. The proposed study is significant because it will define, and mechanistically elucidate, a novel role for MYC in cancer, i.e., activation of oncogenic enhancers/super-enhancers. Downstream to MYC, the contribution of D2HGDH-L2HGDH (via αKG generation) and O-GlucNAcylation will impart a post-translational control of TET function, which challenges the current dogma that these enzymes function exclusively as tumor suppressors.

TET DNA 羟化酶是 α-酮戊二酸 (αKG) 依赖性酶，可催化 5mC 的氧化 5-羟甲基胞嘧啶（5hmC），从而促进DNA去甲基化。单碱基 5hmC 标记的作图 分辨率表明 TET 酶的主要作用是维持基因增强子的低甲基化和 积极的。增强子是转录因子结合以调节基因表达程序的基因组区域。 被转录因子密集占据的高度活跃的增强子簇被称为超级增强子簇。 增强子，通常存在于癌症中。与启动子一样，增强子/超级增强子也受其调节 DNA 甲基化状态，这一过程在癌症中经常出错。因此，考虑到活性增强剂和超 增强子本质上是致癌的，并且 TET 酶使它们保持低甲基化和活性，我们 假设 TET 活性增加本身可能是致癌的。线粒体通过以下方式发挥信号细胞器的作用 产生促进表观遗传变化的底物，包括 DNA 的乙酰化和甲基化 和组蛋白。最近，我们和其他人描述了线粒体和 表观遗传学，其中中间代谢物 αKG 和 2-羟基戊二酸的水平被发现 调节TET酶的活性，从而控制DNA甲基化。这些发现使我们推测 中间代谢在DNA甲基化的控制中起着重要作用。具体来说，我们 假设线粒体酶 D-2- 和 L-2- 羟基戊二酸脱氢酶（D2HGDH 和 L2HGDH) 催化 2-HG 向 αKG 的相互转化，是 线粒体代谢、TET 功能和超级增强子去甲基化/激活。为了扩展这个初始 概念，我们试图识别调节 D2HGDH 和 L2HGDH 表达的上游信号， 因此，影响 TET 功能和增强子甲基化/活性。使用报告基因和 ChIP 检测， 在诱导细胞系和小鼠模型中，我们最近报道 MYC 转录激活 D2HGDH 和 L2HGDH 并以 D2HGDH/L2HGDH/αKG 依赖性方式诱导 TET 功能，从而产生 DNA 体外和体内去甲基化。值得注意的是，我们发现 MYC/D2-L2HGDH/αKG 轴也 促进 TET1、TET2 和 TET3 的核积累，与增强的 O-GlcNAcylation 相关， 由另一种线粒体酶 O-GlcNAc 转移酶 (OGT) 执行的翻译后修饰。 此外，我们初步表明，在弥漫性大 B 细胞淋巴瘤 (DLBCL) 中，MYC 水平与 增强子甲基化和靶基因表达。这些数据共同揭示了一种新的线粒体 信号轴，包括近端的 MYC、中心的 D2/L2HGDH 和 OGT，以及远端的 TET 活性和亚细胞位置。在本提案中，我们将在体外和体内使用人类 B 细胞淋巴瘤模型， 检验总体假设，即中间代谢（部分归因于 MYC 活性）诱导 TET 功能，维持致癌增强子/超级增强子的低甲基化和活性，并促进癌症。我们的 具体目标是： AIM 1) 确定 O-GlcNAcNAc 介导的增加的机制基础 MYC-D2/L2HGDH-αKG轴及其在促进TET核定位和增强子激活中的作用。目标 2) 定义 TET 激活对 MYC 驱动的淋巴瘤发生的贡献 AIM 3) 表征 MYC- B 细胞淋巴瘤中 5hmC 标记和超级增强子激活的驱动图。拟议的研究意义重大 因为它将定义并从机制上阐明 MYC 在癌症中的新作用，即致癌基因的激活 增强子/超级增强子。 MYC 下游，D2HGDH-L2HGDH 的贡献（通过 αKG 生成） O-GlucNAcylation 将赋予 TET 功能翻译后控制，这对当前的 教条认为这些酶专门发挥肿瘤抑制作用。

项目成果

Cyclic-AMP signalling, MYC and hypoxia-inducible factor 1α intersect to regulate angiogenesis in B-cell lymphoma.

环磷酸腺苷信号传导、MYC 和缺氧诱导因子 1α 交叉调节 B 细胞淋巴瘤的血管生成。

• DOI: 10.1111/bjh.18196
• 发表时间: 2022
• 期刊: British journal of haematology
• 影响因子: 6.5
• 作者: Ethiraj,Purushoth;Sasi,Binu;Holder,KennethN;Lin,An-Ping;Qiu,Zhijun;Jaafar,Carine;Elkhalili,Alia;Desai,Parth;Saksena,Annapurna;Ritter,JacobP;Aguiar,RicardoCT
• 通讯作者: Aguiar,RicardoCT

MYC, mitochondrial metabolism and O-GlcNAcylation converge to modulate the activity and subcellular localization of DNA and RNA demethylases.

• DOI: 10.1038/s41375-021-01489-7
• 发表时间: 2022-04
• 期刊: Leukemia
• 影响因子: 11.4
• 作者: Lin AP;Qiu Z;Ethiraj P;Sasi B;Jaafar C;Rakheja D;Aguiar RCT
• 通讯作者: Aguiar RCT