Role for nuclear matrix proteins and DNA methylation for XCI maintenance in female lymphocytes

核基质蛋白和 DNA 甲基化在女性淋巴细胞 XCI 维持中的作用

• 批准号: 10660313
• 负责人: Montserrat C Anguera
• 金额: $ 57.38万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-07 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10660313
• 关键词: Alleles; Antibody Formation; Autoantibodies; Autoantigens; Autoimmune; Autoimmune Diseases; Autoimmunity; B cell differentiation; B-Cell Activation; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Binding Proteins; Biological Assay; Biotinylation; Cell physiology; ChIP-seq; Chromatin; Chronic; Complex; DNA; DNA Methylation; Data; Disease; Dosage Compensation (Genetics); Epigenetic Process; Exhibits; Female; Functional disorder; Gene Dosage; Gene Expression; Gene Modified; Gene Silencing; Genes; Genetic; Genetic Transcription; Goals; Hypermethylation; Immune; Immunity; Impairment; In Vitro; Inflammation; Interferon Type I; Interferons; Link; Lupus; Lupus erythematosus cell; Lymphocyte; Maintenance; Mediating; Methylation; Modification; Molecular; Mus; Nuclear Lamina; Nuclear Matrix-Associated Proteins; Oligonucleotides; Pathway interactions; Patients; Predisposing Factor; Pristane; Process; Production; Protein Methylation; Proteins; Publishing; RNA; RNA Binding; Regulator Genes; Role; SAFB gene; Severity of illness; Signal Transduction; Somatic Cell; Susceptibility Gene; Systemic Lupus Erythematosus; Testing; Therapeutic Intervention; Transcript; Work; X Chromosome; X Inactivation; autosome; biological sex; bisulfite sequencing; cellular imaging; cohesin; cohesion; ds-DNA; gene repression; in vivo; innovation; insight; lupus-like; male; mouse model; novel; overexpression; preservation; promoter; response; whole genome

Females are predisposed for developing systemic lupus erythematosus (SLE), but the underlying mechanisms remain obscure. Females have two X-chromosomes and equilibration of X-linked gene dosage to that of males (XY) occurs by X-Chromosome Inactivation (XCI), initiated and maintained by Xist RNA. The X-chromosome is enriched for immunity-related genes and X-linked genes are typically overexpressed in female-biased SLE, suggesting that impaired XCI maintenance contributes to SLE. Unlike other somatic cells, we found that naïve B cells lack enrichment of Xist RNA and heterochromatic marks, and that these modifications return to the inactive X (Xi) upon in vitro stimulation, which we term `dynamic XCI maintenance'. Our published work demonstrates that SLE patient naïve B cells exhibit abnormal expression of X-linked genes, suggesting a dysfunctional Xist- independent mechanism involving DNA methylation for transcriptional silencing prior to autoantigen stimulation could predispose to lupus. DNA methylation, associated with transcriptional repression, is reduced in SLE patient B cells and is an important epigenetic modification for gene silencing on the Xi. XCI is also regulated by various nuclear matrix proteins, such as hnRNPU and SAFB, which bind to Xist RNA and function to anchor Xist to the Xi or the nuclear lamina in somatic cells. Our preliminary data support the novel concept that Xist RNA transcripts are retained at the nuclear lamina by SAFB in naïve B cells, and that Xist RNA binds to hnRNPU upon B cell activation, tethering Xist RNA to the Xi to regulate transcriptional repression. We have developed a novel Xist deletion mouse model to determine how impaired XCI maintenance contributes to lupus disease, and our exciting preliminary data show that increased dsDNA levels in type I interferon induced disease. Our central hypothesis is that Xist-independent DNA methylation maintains transcriptional repression of the Xi and autosomes in naïve B cells and that upon activation, alterations in nuclear matrix protein binding promotes dynamic XCI maintenance, the dysfunction of which exacerbates Type I IFN-driven lupus disease. We will test our hypotheses with the following aims: (1) Are reductions in Xist-independent DNA hypermethylation in naïve B cells associated with aberrant gene expression in lupus? (2) How do interactions between SAFB, hnRNPU protein and Xist RNA maintain XCI in B cells and does lupus disease impair cohesin eviction by hnRNPU-Xist RNA complexes? (3) How does impaired XCI maintenance impact Type I IFN-driven lupus-like disease in female mice? IMPACT: Our novel and innovative genetic and molecular approaches will yield unprecedented mechanistic insight into how biological sex contributes to immune dysregulation of SLE disease, and will enable the identification of new molecular pathways and targets of female-biased autoimmune disease that could be amenable for therapeutic intervention.

雌性倾向于发展全身性红斑狼疮（SLE），但基本机制 保持晦涩。雌性有两个X染色体和X连锁基因剂量与男性的平衡 （XY）通过XIST RNA引发和维持的X染色体灭活（XCI）发生。 X染色体是 富含免疫相关基因和X连锁基因的基因通常在女性偏见的SLE中过表达， 暗示XCI维护受损会导致SLE。与其他体细胞不同，我们发现幼稚的B 细胞缺乏Xist RNA和异光标记的富集，并且这些修饰返回到不活跃 x（xi）在体外刺激后，我们称其为“动态XCI维护”。我们发表的工作证明了 那个SLE患者幼稚的B细胞表现出X连锁基因的异常表达，表明XIST-功能失调 在自动抗原刺激之前涉及转录沉默的DNA甲基化的独立机制 与转录表达相关的DNA甲基化在SLE患者中降低 B细胞是XI基因沉默的重要表观遗传修饰。 XCI也受各种调节 核基质蛋白，例如HNRNPU和SAFB，它们与Xist RNA结合并功能固定在Xist上 XI或体细胞中的核层。我们的初步数据支持XIST RNA转录本的新颖概念 SAFB在幼稚的B细胞中保留在核层中，并且Xist RNA与B细胞上的HnRNPU结合 激活，将Xist RNA绑定到XI以调节转录表示。我们已经开发了一个小说Xist 删除鼠标模型，以确定XCI维护受损如何有助于狼疮疾病，而我们的令人兴奋的 初步数据表明，I型干扰素诱导疾病中的DsDNA水平提高。我们的中心假设 是独立于XIST的DNA甲基化在幼稚的 B细胞及其激活后，核基质蛋白结合的改变会促进动态XCI 维护，加剧I型IFN驱动狼疮疾病的功能障碍。我们将检验我们的假设 以下目的：（1）是与XIST非依赖性DNA高甲基化相关的幼稚B细胞中的降低 在狼疮中表达异常的基因表达？ （2）SAFB，HNRNPU蛋白和Xist RNA之间的相互作用如何 在B细胞中维持XCI，狼疮疾病是否会损害Hnrnpu-Xist RNA复合物的凝聚素？ （3） XCI维护受损雌性小鼠I类IFN驱动的狼疮样疾病如何受损？影响：我们的 新颖和创新的遗传和分子方法将产生前所未有的机械洞察 生物性别有助于免疫失调SLE病，并将能够鉴定出新的 女性偏见的自身免疫性疾病的分子途径和靶标，可以接受治疗 干涉。