Epigenetics of the autoantibody response in systemic lupus

系统性狼疮自身抗体反应的表观遗传学

• 批准号: 10681392
• 负责人: Paolo Casali
• 金额: $ 71.08万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-24 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10681392
• 关键词: ATAC-seq; Ablation; Address; Affinity; Antibodies; Antibody Response; Ascorbic Acid; Attention; Autoantibodies; Autoimmune Diseases; Autoimmunity; B cell differentiation; B-Cell Activation; B-Lymphocytes; Bacteria; Binding; Butyrates; Cell physiology; Cells; ChIP-seq; Chemosensitization; Cues; DNA; DNA analysis; Data; Development; Down-Regulation; Elements; Enhancers; Epigenetic Process; Estrogens; Female; Fumarates; Gene Expression; Genes; Genetic; Genetic Predisposition to Disease; Genetic Recombination; Genetic Transcription; Histone Deacetylase; Histones; Homologous Gene; Hormonal; Human; Hydroxyl Radical; Immunize; Immunoglobulin Class Switching; Immunoglobulin G; Immunoglobulin Somatic Hypermutation; Immunoglobulins; Impairment; In Vitro; Knock-in; Knock-in Mouse; Left; Ligands; Link; Lupus; Mediating; Mediator; Memory; Metabolic; MicroRNAs; Molecular; Mus; Mutate; Nutritional; PRDM1 gene; Patients; Phosphorylation; Plasma; Plasma Cells; Pristane; Prodrugs; Proteins; Regulation; Rest; Role; SIRT1 gene; Stimulus; Systemic Lupus Erythematosus; Systems Biology; T-Lymphocyte; TNFSF5 gene; Testing; Therapeutic; Transcript; Untranslated RNA; Up-Regulation; Viral; Virus; Vitamin A; Vitamins; activation-induced cytidine deaminase; alpha ketoglutarate; analog; bisulfite; cytokine; demethylation; epigenetic regulation; epigenome; experience; experimental study; genomic locus; glycosylation; histone modification; inhibitor; innovation; mouse model; mutant; neutralizing antibody; novel; organ injury; pathogenic autoantibodies; plasma cell differentiation; posttranscriptional; programs; recruit; response; small molecule; therapeutic target; tissue injury; tool; transcription factor

PROJECT SUMMARY/ABSTRACT. Epigenetics of the autoantibody response in systemic lupus. Like “mature” antibody responses to viruses and bacteria, the lupus autoantibody response requires B cell class- switch DNA recombination (CSR), somatic hypermutation (SHM) and plasma cell differentiation. As we have shown, epigenetic factors, including histone modifiers (such as Sirt1) and inhibitors (such as butyrate) modulate B cell expression of AID (gene: AICDA/Aicda) and Blimp-1 (PRDM1/Prdm1), which are critically for CSR/SHM and plasma cell differentiation, respectively. Towards a better definition of the epigenetic landscape of lupus B cells, we hypothesize that Tet2, a key epigenetic factor, mediates the lupus autoantibody response, as prompted the B cell-intrinsic role of Tet2 in CSR/SHM and plasma cell differentiation (our recent findings). We argue that Tet2 is induced by the stimuli that induce B cell CSR/SHM and plasma cell differentiation, and it is upregulated in lupus B cells. We also argue that Tet2 boosts transcription of Aicda and Prdm1 through its Fe2+ and a- ketoglutarate (a-KG)-dependent catalytic activity for DNA demethylation as well as its non-catalytic function, i.e., recruiting Ogt (encoded by X-linked OGT/Ogt) to these loci to effect histone glycosylation. Finally, we contend that B cell Tet2 transduces hormonal, nutritional and metabolic cues into epigenetic changes to modulate autoantibody responses, as Tet2 transcription could be upregulated by estrogen (E2, our preliminary data) and vitamin A, and Tet2 is activated by vitamin C, but inhibited by fumarate (a metabolite and a-KG competitor) – as shown by us, E2 boosts AID expression, which would enhance females’ antibody and autoantibody responses. With extensive experience in and commitment to the mechanistic understanding of human and mouse lupus autoantibody responses, we are uniquely poised to test our hypotheses using molecular B cell biology systems, cutting-edge epigenetic tools (hydroxylmethyl DNA analysis, bisulfite and oxidative bisulfite conversion, ChIP and ATAC-Seq), genetically modified mice (TgAicda-creTet2fl/fl, Tet2HxD-mut/HxD-mut and Tet2Ogt-mut/Ogt-mut knockin mice, TgAicda-creOgtfl/fl, Tet2HxD-mut/HxD-mutTgAicda-creOgtfl/fl, MRL/Lpr TgAicda-creTet2fl/fl, MRL/Lpr Tet2HxD-mut/HxD-mut and MRL/Lpr TgAicda-creOgtfl/fl), proprietary humanized H-Mice® and Lupus-H-Mice® models. Aim 1 addresses human and mouse B cell differentiation stage-specific (resting, activated, plasma and memory cell) regulation of Tet2, Tet2 protein stability, E2 upregulation of Tet2 transcripts and underlying mechanisms. Aim 2 addresses the B cell- intrinsic role of Tet2 in promoting AID and Blimp-1 expression, the underlying mechanisms (active DNA demethylation and Ogt-mediated histone glycosylation), and potentiation effect of Tet2 inducer vitamin A and activator vitamin C, and suppressive effect of Tet2 catalytic inhibitor (fumarate, TET-IN-C35 or Bobcat339) alone or combined with Ogt ablation or Tet2Ogt-mut/Ogt-mut knockin. Aim 3 analyzes dysregulation of Tet2 and Tet2- mediated epigenetic mechanisms in human and mouse lupus B cells, addresses the role of Tet2 in lupus, and explores Tet2 inhibitors and Ogt inhibitor ST045849 as lupus therapeutics. Our experiments will unveil novel and targetable epigenetic mechanisms that integrate environmental cues to inform the lupus autoantibody response.

项目总结/摘要。系统性狼疮自身抗体反应的表观遗传学。 像对病毒和细菌的“成熟”抗体反应一样，狼疮自身抗体反应需要B类细胞- 开关DNA重组（CSR）、体细胞超突变（SHM）和浆细胞分化。正如我们 表观遗传因子，包括组蛋白修饰剂（如Sirt 1）和抑制剂（如丁酸）调节 AID（基因：AICDA/Aicda）和Blimp-1（PRDM 1/Prdm 1）的B细胞表达，这对CSR/SHM至关重要 和浆细胞分化。对狼疮B的表观遗传景观的更好定义 细胞，我们假设Tet 2，一个关键的表观遗传因子，介导狼疮自身抗体反应，提示 Tet 2在CSR/SHM和浆细胞分化中的B细胞内在作用（我们最近的发现）。我们认为 Tet 2由诱导B细胞CSR/SHM和浆细胞分化的刺激物诱导，并且其被上调 在狼疮B细胞中。我们还认为Tet 2通过其Fe 2+和a- 酮戊二酸（α-KG）依赖性的DNA去甲基化催化活性以及其非催化功能，即， 将Ogt（由X-连锁的OGT/Ogt编码）募集到这些基因座以实现组蛋白糖基化。最后，我们主张 B细胞Tet 2将激素、营养和代谢信号转换成表观遗传变化， 自身抗体应答，因为Tet 2转录可以被雌激素上调（E2，我们的初步数据）， Tet 2被维生素C激活，但被富马酸盐（一种代谢产物和a-KG竞争剂）抑制-如 我们发现，E2促进AID表达，这将增强女性的抗体和自身抗体应答。 在人类和小鼠狼疮的机制理解方面有着丰富的经验和承诺 自身抗体反应，我们独特地准备使用分子B细胞生物学系统来测试我们的假设， 尖端的表观遗传工具（羟甲基DNA分析，亚硫酸氢盐和氧化亚硫酸氢盐转化，ChIP 和ATAC-Seq），遗传修饰的小鼠（TgAicda-creTet 2fl/fl，Tet 2 HxD-mut/HxD-mut和Tet 2 Ogt-mut/Ogt-mut敲入小鼠， TgAicda-creOgtfl/fl、Tet2HxD-mut/HxD-mutTgAicda-creOgtfl/fl、MRL/Lpr TgAicda-creTet2fl/fl、MRL/Lpr Tet2HxD-mut/HxD-mut和MRL/Lpr TgAicda-creOgtfl/fl）、专有人源化H-Mice®和Lupus-H-Mice®模型。目标1针对人类， 小鼠B细胞分化阶段特异性（静息、活化、血浆和记忆细胞）调节Tet 2，Tet 2 蛋白质稳定性、Tet 2转录物的E2上调和潜在机制。目标2针对B细胞- Tet 2在促进AID和Blimp-1表达中的内在作用，潜在机制（活性DNA）， 去甲基化和Ogt介导的组蛋白糖基化），以及Tet 2诱导剂维生素A和 激活剂维生素C和Tet 2催化抑制剂（富马酸盐、TET-IN-C35或Bobcat 339）单独的抑制作用 或与Ogt消融或Tet 2 Ogt-mut/Ogt-mut敲入组合。目的3分析Tet 2和Tet 2- 在人类和小鼠狼疮B细胞中介导的表观遗传机制，阐述了Tet 2在狼疮中的作用， 探索Tet 2抑制剂和Ogt抑制剂ST 045849作为狼疮治疗剂。我们的实验将揭示新的， 整合环境线索以告知狼疮自身抗体反应的靶向表观遗传机制。