Role of Chromatin Bridges in Activating Innate Immune Signaling following Failed Mitosis

染色质桥在有丝分裂失败后激活先天免疫信号中的作用

• 批准号: 10230804
• 负责人: Patrick J Flynn
• 金额: $ 3.78万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10230804
• 关键词: Actins; Aging; Anaphase; Antimitotic Agents; Antiviral Agents; Attention; Autoimmune Diseases; Automobile Driving; Binding Proteins; Biological Assay; Biology; Bloom Syndrome; Cell Death; Cell division; Cell model; Cells; Cellular biology; Centromere; Characteristics; Chromatin; Chromatin Structure; Chromosomal Instability; Chronic; Cyclic GMP; Cytoplasm; DNA; Disease; Dose; Drug Screening; Drug usage; Exhibits; Exposure to; Failure; Frequencies; Gap Junctions; Genetic; Genetic Models; Genomic DNA; Genomics; Image; Immune signaling; Immune system; Inflammation; Inflammatory; Inherited; Innate Immune Response; Interferon-alpha; Interferons; Learning; Length; Link; Malignant Neoplasms; Mammalian Cell; Measures; Mediating; Methods; Mitosis; Mitotic; Modeling; Molecular; Molecular Target; Mutation; Neoplasm Metastasis; Nucleosomes; Pathologic; Pathology; Patients; Pharmaceutical Preparations; Pharmacology; Play; Production; Proliferating; Proteins; Reporting; Research; Resolution; Role; Signal Transduction; Sister; Sister Chromatid; Spontaneous Rupture; Stains; Stretching; Structural defect; Syndrome; Synthase I; Testing; Topoisomerase; Work; cancer cell; cancer predisposition; cancer therapy; cell motility; chemotherapy; cytokine; density; helicase; human disease; improved; innate immune pathways; insight; loss of function mutation; novel; prevent; recruit; sensor; success; telomere; tumor; tumorigenesis; viral DNA

PROJECT SUMMARY/ABSTRACT Abnormal chromatin structures produced by errors in cell division can cause cell death, propagate genetic instability and, potentially, induce inflammatory signaling. Micronuclei and chromatin bridges (CBs) are two types of abnormal structures which are frequently observed in cells from cancers and cancer-related diseases such as Blooms Syndrome (BS). Aberrant chromatin structures can expose genomic self-DNA to the cytoplasm which activates anti-viral inflammatory signaling. Cytoplasmic self-DNA (cyDNA) triggers type-1 interferon (IFN) signaling through multiple innate immune pathways, of which the cGAS-STING axis is most prominent. However, only micronuclei have been studied for their potential to induce IFN signaling. Prior reports suggested that micronuclei spontaneously rupture and produce cyDNA which then activates cGAS. Surprisingly, I have identified that CBs, not micronuclei, are responsible for cGAS activation and IFN induction after failed mitosis. I propose to investigate the molecular and physical mechanisms underlying cGAS activation by CBs. I will use drug-induced mitotic failure or cellular models of BS to study CBs. I will investigate how cGAS-activating CBs arise from errors in cell division, how CBs activate cGAS and whether cGAS- activating CBs are generated in cellular models of BS. I hypothesize that inflammatory CBs are formed by unresolved catenations or merotelic attachments and activate cGAS through a tension-dependent mechanism. To test this hypothesis, I first will analyze CBs produced by drug-induced mitotic failure to determine their formation mechanism. I then will generate CBs through alternative methods, such as topoisomerase inhibition, to determine whether these CBs similarly activate cGAS. In my second aim I will investigate whether actin- mediated tension across the CB is required for cGAS activation. I will test my hypothesis that tension on CBs facilitates cGAS activation through the extrusion of chromatin-bound proteins. In aim 3 I will study cellular models of BS. BS is an inherited cancer pre-disposition syndrome characterized by chromosomal instability and frequent CBs. BS is caused by loss of function mutations in the BLM helicase and cells with a defective BLM helicase exhibit a high number of unresolved sister chromatid catenations during anaphase. I will study whether these catenations turn into cGAS-activating CBs, and if this occurs through the tension-dependent mechanism identified in aim 2. The Mitchison lab provides me an excellent space to explore the nexus of mitotic mechanisms and innate immune signaling. We have made important discoveries in the biology of mammalian cell division and the mechanisms of anti-mitotic chemotherapy. I propose to partake in this tradition by studying the inflammatory consequences of mitotic failure and its potential role in the pathology of Blooms Syndrome.

项目摘要/摘要 细胞分裂中错误产生的异常染色质结构会导致细胞死亡，传播遗传 不稳定性，并可能诱发炎症信号传导。微核和染色质桥（CBS）为两个 异常结构的类型，这些结构经常在癌症和与癌症相关疾病的细胞中观察到 例如Blooms综合征（BS）。异常染色质结构可以将基因组自DNA暴露于 激活抗病毒炎症信号传导的细胞质。细胞质自DNA（CYDNA）触发1型1 干扰素（IFN）通过多个先天免疫途径发出信号，其中CGAS轴最多 著名的。但是，仅研究了微核诱导IFN信号传导的潜力。事先的 报告表明，微核自发破裂并产生cydna，然后激活CGA。 令人惊讶的是，我已经确定CBS而不是微核是CGAS激活和IFN诱导的原因 有丝分裂失败后。我建议研究CGA的分子和物理机制 CBS激活。我将使用药物诱导的有丝分裂衰竭或BS的细胞模型来研究CBS。我会调查 CGA激活的CB如何来自细胞分裂的错误，CBS如何激活CGA以及CGAS-是否会产生 激活CB是在BS的细胞模型中产生的。我假设炎症CB是由 未分辨的搭配或商制附着，并通过张力依赖性机制激活CGA。 为了检验这一假设，我首先将分析药物诱导的有丝分裂失败产生的CBS，以确定其 形成机制。然后，我将通过替代方法（例如拓扑异构酶抑制）生成CBS 确定这些CBS是否类似地激活CGA。在我的第二个目标中，我将调查肌动蛋白是否 - CGA激活需要跨CB的介导张力。我将测试我的cbs张力的假设 通过挤出染色质结合的蛋白来促进CGA激活。在AIM 3中，我将研究细胞 BS的模型。 BS是一种以染色体不稳定性为特征的遗传性癌症前的疾病综合征 和频繁的CBS。 BS是由BLM解旋酶和细胞缺陷的功能突变引起的 BLM解旋酶在后期期间表现出大量未解决的姐妹染色单体搭配。我会学习 这些相互作用是否变成CGA激活的CB，并且是否通过张力依赖性发生 在AIM 2中确定的机制。米奇森实验室为我提供了一个探索联系的绝佳空间 有丝分裂机制和先天免疫信号传导。我们已经在生物学的重要发现 哺乳动物细胞分裂和抗二裂化化疗的机制。我建议参与这一传统 通过研究有丝分裂衰竭的炎症后果及其在盛开病理中的潜在作用 综合征。