Role of KLF15 in proximal tubule metabolism

KLF15 在近曲小管代谢中的作用

• 批准号: 10481366
• 负责人: Sandeep K Mallipattu
• 金额: --
• 依托单位: NORTHPORT VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10481366
• 关键词: Acetyl Coenzyme A; Acute Renal Failure with Renal Papillary Necrosis; Agonist; American; Anabolism; Aristolochic Acids; Attenuated; Binding Sites; Cardiovascular Diseases; Cell Cycle Arrest; Cell Differentiation process; Cell physiology; Cells; ChIP-seq; Chronic Kidney Failure; Cisplatin; Clinical; Compensation; DNA Damage; DNA Repair; Data; Diglycerides; Down-Regulation; Fatty Acids; Fibroblasts; Funding; General Population; Generations; Genes; Glycolysis; Goals; Human; Injury; Injury to Kidney; Ischemia; Kidney; Lipids; Mediating; Metabolic; Metabolic Pathway; Metabolism; Mitochondria; Mus; Myofibroblast; Nonesterified Fatty Acids; Organoids; Oxidative Stress; PPAR alpha; Palmitates; Pathway interactions; Phase; Pre-Clinical Model; Predisposition; Prevalence; Production; Profibrotic signal; Proliferating; Reactive Oxygen Species; Recovery; Regression Analysis; Regulation; Renal glomerular disease; Research; Respiration; Risk Factors; Role; Secondary to; Signal Transduction; Signaling Molecule; Source; Testing; Therapeutic; Toxin; Transcriptional Regulation; Triglycerides; United States Department of Veterans Affairs; Veterans; cardiovascular risk factor; cell dedifferentiation; cell injury; chemotherapeutic agent; clinically relevant; extracellular; in silico; inducible gene expression; interest; kidney biopsy; knock-down; macromolecule; mouse model; novel; novel therapeutic intervention; overexpression; oxidation; peroxidation; prevent; repaired; single nucleus RNA-sequencing; transcription factor; transcriptome sequencing

Chronic kidney disease (CKD) is a leading risk factor for cardiovascular disease, with a disproportionate burden on U.S. Veterans. Recent data demonstrates that acute kidney injury (AKI), despite initial renal recovery, is a major risk factor for CKD. The proximal tubule (PT) is the primary target in AKI due to its high susceptibility to ischemia and DNA-damaging nephrotoxins such as chemotherapeutic agents. Damaged PT cells dedifferentiate, and initially undergo cell cycle arrest, predominantly at the G2/M checkpoint. This cell cycle arrest may allow repair of DNA damage caused by reactive oxygen species secondary to mitochondrial damage or directly by DNA-damaging toxins. Sustained cell cycle arrest is associated with a switch to secretion of pro-fibrotic signaling molecules, inducing resident fibroblasts to proliferate and differentiate to myofibroblasts, beginning the transition to a fibrotic injury. PT cells also undergo metabolic reprograming, with severe downregulation of fatty acid b-oxidation (FAO), and limited compensation by anerobic glycolysis. While restoring FAO either by overexpressing Ppara or by using a peroxisome proliferator activated receptor alpha (PPARa) agonist attenuates AKI and CKD in murine models, this has not translated to use in clinical AKI, suggesting additional factors are required to mitigate the progression from AKI to CKD. Krüppel-Like Factor 15 (KLF15) is a kidney-enriched transcription factor, involved in a diverse range of cellular processes, including cell differentiation and FAO. In the initial funding period of the VA Merit, we demonstrated the salutary role of KLF15 in glomerular disease leading to a composition-of-matter IP on KLF15 agonists by the Veterans Affairs. During this initial period, we also identified that KLF15 is highly expressed in differentiated PT cells, but is significantly reduced in murine models of PT injury. Utilizing a murine model of PT-specific injury secondary to DNA damage, we observed that PT-specific knockdown of Klf15 exacerbated AKI as well as CKD. PT-specific knockdown of Klf15 also increased pathways involving cell cycle arrest, oxidative stress, pro-fibrotic signaling and a decrease in pathways utilizing FA for the generation of acetyl-CoA, a central metabolic intermediate in macromolecule biosynthesis and energy production. We also observed an enrichment of genes critical for FA utilization with putative and proximal KLF15- and PPARa-binding sites, suggesting potential KLF15-PPARa co-operativity in the regulation of FA utilization. In addition, we demonstrated a significant increase in glycerolipid synthesis pathways and lipid droplet formation in the setting of suppressed FAO, suggesting a potential compensatory mechanism post-DNA damage. KLF15 expression was also associated with PPARA expression in human kidney biopsies with and without CKD. In addition, multivariate regression analysis demonstrated that a decrease in KLF15 expression was independently associated with eGFR decline, suggesting that the loss of KLF15 might be a key driver of PT injury. Based on these preliminary data and strong scientific rigor of prior research, we hypothesize that KLF15-PPARa co-operativity drives the utilization of excess free fatty acids for acetyl-CoA and glycerolipid synthesis to prevent maladaptive PT repair post-DNA damage. We propose to test this hypothesis by (1) determining the mechanism by which KLF15-PPARa co-operativity restores PT metabolism after PT injury secondary to DNA-damage and (2) to investigate the requisite role of KLF15-PPARa in PT injury secondary to DNA-damage. This proposal will address a current gap in the field by investigating the mechanisms mediating transcriptional regulation of FA utilization in the PT cells post-DNA damage. The long-term goal of our project is to demonstrate that the combination of KLF15 and PPARa agonists is a novel therapeutic strategy to mitigate PT injury post-DNA damage. Identification of novel targets for the treatment of AKI is of major interest to the VA, given the high burden of CKD among U.S. Veterans.

慢性肾病（CKD）是心血管疾病的主要危险因素， 美国退伍军人的伯纳伦（Burnen）不成比例。最近的数据表明，急性肾脏受伤（AKI），绝望 最初的肾脏回收是CKD的主要危险因素。近端小管（PT）是AKI的主要目标 它对缺血和减轻DNA的肾毒素（如化学治疗剂）的高敏感性。 受损的PT细胞被降低，最初会在G2/M检查点进行细胞周期停滞。 这种细胞周期停滞可能允许修复由继发的活性氧引起的DNA损伤 线粒体损伤或直接通过DNA破坏毒素。持续的细胞周期停滞与 切换到促纤维化信号分子的分泌，诱导的居民成纤维细胞增殖和 与肌纤维细胞区分开，开始过渡到纤维化损伤。 PT细胞也经历了代谢 重新编程，严重下调脂肪酸B氧化（FAO），并通过 厌氧糖酵解。通过过度表达PPARA或使用过氧化物组增殖剂来恢复FAO 激活的受体α（PPARA）激动剂减弱了鼠模型中的AKI和CKD，这尚未转化为 在临床AKI中使用，提示需要其他因素来减轻从AKI到CKD的发展。 Krüppel样因子15（KLF15）是肾脏增强的转录因子，涉及潜水员的范围 细胞过程，包括细胞分化和粮农组织。在VA优点的最初资助期间，我们 证明了KLF15在肾小球疾病中的有益作用 退伍军人事务的激动剂。在此初期，我们还确定了KLF15在 分化的PT细胞，但在PT损伤的鼠模型中显着降低。利用鼠模型 DNA损伤继发的PT特异性损伤，我们观察到KLF15的PT特异性敲低恶化 AKI和CKD。 KLF15的PT特异性敲低还增加了涉及细胞周期停滞的途径， 氧化应激，促纤维化信号传导和利用FA产生乙酰辅酶A的途径减少， 大分子生物合成和能量产生中的中央代谢中间体。我们还观察到 富集对FA利用至关重要的基因，其推定和近端KLF15-和PPARA结合位点， 提示潜在的KLF15-PPARA合作社在FA利用的调节中。另外，我们 在情况下显示出甘油脂合成途径和脂质液滴的显着增加 被抑制的粮农组织，表明DNA损伤后具有潜在的补偿机制。 KLF15表达 也与有或没有CKD的人类肾脏活检中的PPARA表达有关。此外， 多元回归分析表明，KLF15表达的降低是独立的 与EGFR下降有关，表明KLF15的损失可能是PT损伤的关键驱动力。 基于这些初步数据和先前研究的严格严格，我们假设 KLF15-PPARA合作性驱动了过量的游离脂肪酸在乙酰辅酶A和甘油中的利用 合成以防止适应不良的DNA损伤后不良适应性PT修复。我们建议通过（1）检验这一假设 确定KLF15-PPARA合作率在PT损伤后恢复PT代谢的机制 继发于DNA破坏的继发于（2），研究KLF15-PPARA在PT损伤中的必要作用 DNA破坏。该建议将通过调查介导的机制来解决该领域的当前差距 DNA损伤后PT细胞中FA利用的转录调节。我们项目的长期目标 是为了证明KLF15和PPARA激动剂的组合是一种新型的治疗策略 减轻DNA损伤后PT损伤。识别新型AKI治疗的目标是主要感兴趣的 鉴于美国退伍军人的CKD负担很高，到VA。