Transcriptional and epigenetic control of angiogenic genes in sepsis-induced acute kidney injury.

脓毒症引起的急性肾损伤中血管生成基因的转录和表观遗传控制。

• 批准号: 9334850
• 负责人: KAROL BOMSZTYK
• 金额: $ 26.39万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-20 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9334850
• 关键词: ANGPT1 gene; Acute Renal Failure with Renal Papillary Necrosis; Angiopoietin-2; Angiopoietins; Antibodies; Binding Proteins; Biological Assay; Blood Vessels; Blood flow; Cell Culture Techniques; Chromatin; Clinical; Clinical Trials; Complication; Critical Illness; DNA-Binding Proteins; Data; Down-Regulation; Drug Targeting; Embryo; Endothelial Cells; Epigenetic Process; Event; Extravasation; Family member; Functional disorder; Future; Gene Expression; Genes; Genetic Transcription; Heterogeneity; Hospitalization; Human; In Vitro; Inflammation Mediators; Injury; Intervention; Kidney; Kinetics; Knock-out; Life; Ligands; Mediating; Modeling; Molecular; Organ; Pathologic; Pathway Analysis; Patients; Pericytes; Pharmacology; Play; Preparation; Process; Proteomics; Receptor Protein-Tyrosine Kinases; Regulation; Regulator Genes; Repression; Risk; Role; Sampling; Sepsis; Signal Transduction; Source; TIE-2 Receptor; Testing; Time; Transgenic Mice; base; combinatorial; design; endothelial dysfunction; hypoperfusion; in vitro testing; knock-down; mortality; mouse model; novel; response; septic; tool; transcription factor

Sepsis-induced acute kidney injury (AKI) is the most common and life-threatening cause of renal injury in critically ill patients. And yet, there have been no improvements in the treatment of septic AKI in decades. Septic AKI is distinct from non-septic AKI; notably - microcirculatory dysfunction manifested by low blood flow, endothelial cell (EC) activation and vascular leak, play a prominent pathologic roles. The microvasculature consists of luminal EC and pericytes, which encircle the abluminal endothelial wall. The EC receptor tyrosine kinase, Tie-2 (TEK), and its two ligands, angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2), (i.e., Ang-Tie-2 axis) regulate microvasculature. Pericytes are the primary source of Ang-1, which maintains EC quiescence via Tie-2 signaling. Tie-2 expression/signaling is, part, regulated by blood flow, a process that involves transcription factor, Klf2. Tie-2 and Ang-1 gene expression is downregulated in septic kidney, contributing to EC dysfunction. Changes in Tie-2/ Ang-1 expression are associated with epigenetic alterations and loss of Klf2 at these loci. We will test the hypothesis that sepsis-induced Klf2 disengagement from Ang-1 and Tie-2 genes alters dynamic network(s) of transcription and epigenetic factors interacting along Ang-1 and Tie-2 loci which down-regulates their transcription and contributes to endothelial leak. Aim #1. To define kinetics of transcription/epigenetic network changes associated with disengagement of Klf2 from renal Ang-1 and Tie-2 genes in mouse models of sepsis. Correlating kinetics of sepsis-induced transcription/epigenetic alterations at the renal Ang-1 and Tie-2 genes with progression to endothelial leak will identify Klf2-dependent and -independent interactions that will be tested in vitro (Aims #2-3) for their role inTie-2 and Ang-1 expression. Aim #2. To use EC and pericyte cultures to define which interactions of chromatin-bound proteins act (additively, synergistically or antagonistically) to regulate Tie-2 and Ang-1 transcription. Mechanism of Tie-2 and Ang-1 repression will be studied by knocking down/inhibiting candidate factors (e.g., HDACs) tethered to these loci. Aim #3. To characterize which of transcription/epigenetic factor interactions at Tie-2 and Ang-1 loci are responsive to flow/inflammatory mediators and regulate microvascular barrier in in vitro 3D- flow microvessels. We will take advantage of our synthetic human kidney microvessels that model endothelial leak to identify flow-responsive transcription/epigenetic interactions that regulate Ang-1 and Tie-2 genes. We have recently demonstrated, previously unanticipated, epigenetic heterogeneity and uniqueness of gene responses during AKI. Thus, defining key transcription/epigenetic network components engaged at Ang-1 and Tie-2 genes as potential drug targets will provide translational basis for future testing combinatorial rationally- designed pharmacologic interventions to mitigate microvascular leak and kidney injury during sepsis.

败血症引起的急性肾脏损伤（AKI）是肾损伤的最常见和威胁生命的原因 重病患者。然而，几十年来，对化粪池AKI的治疗没有改善。 化粪池Aki与非污点AKI不同。值得注意的 - 微循环功能障碍表现为低血流， 内皮细胞（EC）激活和血管泄漏起着突出的病理作用。微脉管系统 由腔内EC和周环组成，它们环绕着空白的内皮壁。 EC受体酪氨酸 激酶，TIE-2（TEK）及其两个配体Angiopoietin-1（Ang-1）和Angiopoietin-2（Ang-2）（即Ang-Tie-2） 轴）调节微脉管系统。周细胞是Ang-1的主要来源，它通过 TIE-2信号传导。 TIE-2表达/信号传导是由血流调节的，该过程涉及 转录因子，KLF2。 TIE-2和ANG-1基因表达在化脓性肾脏中下调，导致EC 功能障碍。 TIE-2/ ANG-1表达的变化与表观遗传改变和KLF2的丧失有关 这些基因座。我们将检验以下假设，即败血症引起的KLF2脱离Ang-1和Tie-2 基因改变了沿着Ang-1和的表观遗传因子的动态网络（S） TIE-2基因座下调其转录并导致内皮泄漏。 目标＃1。定义转录/表观遗传网络变化的动力学 在败血症小鼠模型中，KLF2从肾ANG-1和TIE-2基因中脱离接触。相关动力学 败血症诱导的转录/表观遗传学改变，肾ANG-1和TIE-2基因的进展为 内皮泄漏将识别将在体外测试的KLF2依赖性和独立的相互作用（AIMS＃2-3） 因为它们的角色Intie-2和Ang-1表达。 目标＃2。使用EC和周细胞培养物来定义染色质结合的哪些相互作用 蛋白质作用（在添加，协同上或拮抗方面）调节TIE-2和ANG-1转录。 TIE-2和ANG-1抑制的机制将通过击倒/抑制候选因素来研究（例如， HDACS）绑在这些基因座上。 目标＃3。表征在TIE-2和ANG-1处的转录/表观遗传因子相互作用 基因座对流动/炎症介体的反应敏感，并调节体外3D-的微血管屏障 流动微血管。我们将利用模型内皮的合成人类肾脏微血管 泄漏以识别调节ANG-1和TIE-2基因的流动反应转录/表观遗传相互作用。 我们最近证明了，以前意外的表观遗传异质性和基因独特性 AKI期间的回应。因此，定义在Ang-1和Ang-1和 TIE-2基因作为潜在的药物靶标将为将来的测试组合提供转化基础。 设计了药理学干预措施，以减轻败血症期间的微血管泄漏和肾脏损伤。