Mitochondrial R-loop in sepsis-induced cardiomyopathy

脓毒症诱发的心肌病中的线粒体 R 环

基本信息

批准号：
10586871
负责人：
Wei Huang
金额：
$ 44.52万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-12 至 2027-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10586871
关键词：
3-Dimensional Adaptive Immune System Alternative Therapies Architecture Automobile Driving Binding Cardiac Myocytes Cardiomyopathies Cardiovascular system Cells Chromatin Chronic Clinical Clinical Research DNA DNA Methylation Data Defect Disease Progression Engineering Enhancers Epigenetic Process Failure Functional disorder Future Genetic Genetic Transcription Genome Mappings Genomic Instability Goals Heart Heart Diseases Heart failure Hybrids Immune Immune System Diseases Immune response Immunity Immunotherapy Infection Infiltration Inflammation Inflammatory Inflammatory Response Intervention Knowledge Life Link Macrophage Mediating Medicine Mitochondria Mitochondrial DNA Mitochondrial Matrix Molecular Monitor Morbidity - disease rate Mus Myocardial dysfunction Names Nucleic Acids Organ Outcome Pathologic Pathway interactions Patients Pattern Pilot Projects Play Process RNA Recovery Regulation Reporter Role Sepsis Signal Transduction Signaling Molecule Stress Structure Sumoylation Pathway Testing Therapeutic Therapeutic Intervention Time Transcriptional Activation Transcriptional Regulation Untranslated RNA cardioprotection cardiovascular risk factor design epigenome epigenome editing epigenomics experimental study extracellular heart damage heart function improved intercellular communication mitochondrial genome mortality novel novel therapeutic intervention preclinical study prevent promoter response septic septic patients therapeutic target tool transmission process uptake

项目摘要

Abstract Sepsis is a life-threatening organ dysfunction that induces a multitude of defects in immunity for sustained periods of time after clinical recovery that is closely correlated with long-term mortality associated with septic cardiomyopathy. Although immune-based therapies have been designed to suppress inflammatory responses, this strategy alone has marginal benefits for sepsis patients, as the dominant molecular drivers of septic cardiomyopathy-associated inflammation remain unclear. As our knowledge of mitochondria advances, we first investigated a previously underappreciated activator in inflammation and disease progression, mitochondrial R- loop (RNA:DNA hybrid) termed mtR-loop, and discovered aberrant accumulation in cardiomyocytes after sepsis. The contributory role of mtR-loop toward cardiomyopathy post sepsis was documented in a pilot study showing that unresolved mtR-loop is pathological, which is linked to not only mitochondrial genome instability, but also unresolved chronic inflammation through activating both non-immune cells (cardiomyocytes) and immune cells (macrophages). Most importantly, these cardiomyocyte-derived mtR-loop could translocate to extracellular compartments and were sensed by macrophages in the heart to fuel a fata response to sepsis. This proposal will test the hypothesis that septic cardiomyocyte derived mtR-loop are the central hub that connect various pathways of the immune response in the inflammatory network. If identified, mtR-loop inhibition will be explored as a potential novel cardio-protector against stress. To this, we will employ genetic tools combined with reporter mice to monitor mtR-loop translocation within cells, track mtR-loop uptake by immune cells, define the mechanism underlying mtR-loop intercellular communication and initiated inflammation, and characterize the infiltrating cells. Mechanistically, our pilot data first showed that the SUMOlyation-dependent packaging of lncRNA (lncRP11) into mitochondria, which hybrids with mtDNA to form mtR-loop (lncRNA:mtDNA structure). Those lncRNA-associated mtR-loop acts an upstream trigger of inflammatory network in septic hearts. Based on these initial findings, we hypothesize that suppression of lncRP11 transcription can reduce or prevent cardiac dysfunction in post-sepsis by directly reversing or ameliorating inflammation associated with cardiomyocyte failure. Specifically, by 3D genome mapping, the physical contact of enhancer and promoter, but not their activities, was identified to regulate lncRP11 transcription in septic hearts. Interestingly, this is largely due to loss of CTCF-mediated insulator between lncRP11 promoter and enhancer. In addition, the CTCF binding on the insulator is sensitive to DNA methylation. Thus, we propose that gain of CTCF-mediated insulator by epigenetic editing tool could block enhancer/promoter interaction and thus silence lncRP11 transcription. Results of these studies will be used to develop a viable therapeutic approach using targeted epigenetic editing, which can efficiently resolve lncRP11-associated pathological mtR-loop and thereby ameliorate stress-induced cardiac damage and reduce the mortality and morbidity of patients with septic cardiomyopathy.

抽象的脓毒症是一种危及生命的器官功能障碍，可导致持续的多种免疫缺陷临床恢复后的一段时间，与脓毒症相关的长期死亡率密切相关心肌病。尽管基于免疫的疗法旨在抑制炎症反应，作为脓毒症的主要分子驱动因素，这种策略本身对脓毒症患者具有边际效益心肌病相关炎症仍不清楚。随着我们对线粒体认识的不断进步，我们首先研究了一种以前被低估的炎症和疾病进展激活剂，线粒体 R- 环（RNA：DNA杂合体）称为mtR环，并发现脓毒症后心肌细胞中异常积累。一项初步研究记录了 mtR 环对脓毒症后心肌病的促进作用，显示未解决的 mtR 环是病理性的，这不仅与线粒体基因组不稳定有关，还与通过激活非免疫细胞（心肌细胞）和免疫细胞来解决未解决的慢性炎症（巨噬细胞）。最重要的是，这些心肌细胞衍生的 mtR 环可以易位到细胞外并被心脏中的巨噬细胞感知，以促进 Fata 对脓毒症的反应。这个提议将检验脓毒症心肌细胞衍生的 mtR 环是连接各种细胞的中心枢纽的假设炎症网络中免疫反应的途径。如果确定，将探索 mtR 环抑制作为一种潜在的新型抗压力心脏保护剂。为此，我们将采用遗传工具与记者相结合小鼠监测细胞内 mtR 环易位，跟踪免疫细胞对 mtR 环的摄取，定义 mtR 环细胞间通讯和引发炎症的机制，并表征浸润细胞。从机制上讲，我们的试验数据首先表明，SUMOlyation 依赖性包装 lncRNA (lncRP11) 进入线粒体，与 mtDNA 杂交形成 mtR 环（lncRNA:mtDNA 结构）。这些 lncRNA 相关 mtR 环在脓毒症心脏中充当炎症网络的上游触发因素。基于根据这些初步发现，我们假设抑制 lncRP11 转录可以减少或预防心脏疾病通过直接逆转或改善与心肌细胞相关的炎症来治疗脓毒症后的功能障碍失败。具体来说，通过 3D 基因组作图，增强子和启动子的物理接触，但不是它们的接触活性，被确定可调节脓毒症心脏中的 lncRP11 转录。有趣的是，这很大程度上是由于损失 CTCF 介导的 lncRP11 启动子和增强子之间的绝缘体。此外，CTCF 绑定在绝缘体对 DNA 甲基化敏感。因此，我们建议通过表观遗传获得 CTCF 介导的绝缘体编辑工具可以阻断增强子/启动子相互作用，从而沉默 lncRP11 转录。这些结果研究将用于开发一种使用靶向表观遗传编辑的可行治疗方法，该方法可以有效解决lncRP11相关的病理性mtR环，从而改善应激诱发的心脏损害并降低脓毒症心肌病患者的死亡率和发病率。