Peptidylarginine deiminase-4 and acute kidney injury

肽基精氨酸脱亚胺酶 4 与急性肾损伤

• 批准号: 9423315
• 负责人: H. Thomas Lee
• 金额: $ 36万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-13 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9423315
• 关键词: Acute Renal Failure with Renal Papillary Necrosis; Affect; Apoptosis; Arginine; Arginine deiminase; Attenuated; Binding; Blood Vessels; Cardiac; Cell Death; Cell Line; Cell model; Cells; Citrulline; Clinical; Data; Enterobacteria phage P1 Cre recombinase; Event; Genetic; Goals; Health Care Costs; Human; In Vitro; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Injury; Ischemia; Kidney; Kidney Transplantation; Leukocytes; Liver; Mediating; Mus; Necrosis; Neutrophil Infiltration; Nuclear; Operative Surgical Procedures; Patients; Peptides; Perioperative; Pharmacology; Play; Protein-arginine deiminase; Proteins; Proximal Kidney Tubules; Receptor Activation; Recombinants; Reperfusion Injury; Reperfusion Therapy; Role; Signal Transduction; T-Lymphocyte; Testing; Tubular formation; Up-Regulation; analog; base; cGMP-dependent protein kinase Ibeta; cell injury; cell type; chemokine; clinical care; cytokine; design; effective therapy; extracellular; in vivo; kidney cell; mortality; neutrophil; novel; novel therapeutics; receptor; renal ischemia; translational approach

Acute kidney injury (AKI) due to ischemia and reperfusion (IR) is a major unresolved clinical problem with extremely high mortality and health care costs and ischemic AKI frequently complicates major vascular, cardiac and liver surgeries. Although renal tubular inflammation is a major mechanism of ischemic AKI, there is no effective therapy to limit the inflammatory response after renal IR injury impeding effective perioperative clinical care. Peptidyl arginine deiminase-4 (PAD4) catalyzes the post-translational conversion of arginine to citrulline. Our recent novel findings show that that kidney proximal tubule cells not only express functional PAD4 but also that renal IR injury increases the renal tubular PAD4 expression and activity in mice. Furthermore, pharmacological PAD4 inhibition or genetic PAD4 deletion significantly reduced renal tubular inflammation (cytokine/chemokine expression and neutrophil infiltration) and injury after IR. In contrast, recombinant human PAD4 protein exacerbated renal tubular inflammation and injury after IR. However, the mechanisms of PAD4 induction after renal IR, the cell type(s) in the kidney where the PAD4 induction occurs as well as the downstream cellular signaling events generated by renal PAD4 activation remain unknown. Exciting preliminary data suggest that extracellular ATP and its analogs induce renal proximal tubular cell PAD4 by activating P2X7 receptors. This is highly significant as recent studies showed that extracellular ATP released by necrotic cells after IR further promotes inflammation and cell death. Our preliminary data also suggest that PAD4 citrullinates and increases the activity of renal proximal tubular IkBα kinase γ (IKKγ also known as NFkB Essential MOdulator or NEMO) to induce pro-inflammatory cytokines via nuclear NFkB translocation. In addition, our preliminary studies suggest that blocking NEMO activation protects against recombinant PAD4-induced exacerbation of ischemic AKI in mice. Based on these preliminary data, our central hypothesis is that extracellular ATP-mediated induction of renal proximal tubular PAD4 exacerbates kidney inflammation and injury after IR via enhanced NEMO citrullination and activation. Furthermore, we hypothesize that inhibiting renal tubular NEMO activation protects against kidney injury and inflammation after IR. We will utilize both in vivo (murine renal IR) and in vitro (proximal tubule cells) models to further elucidate the mechanisms and discover potential therapy for ischemic AKI by testing the following 3 specific aims. Aim #1: To identify the renal cell type and determine the mechanisms of PAD4 induction after ischemic AKI. Aim #2: To elucidate the mechanisms of PAD4-mediated renal inflammation after ischemic AKI. Aim #3: To develop novel therapies for ischemic AKI by selectively targeting proximal tubule NEMO. In summary, our translational approaches will provide a novel understanding of the mechanisms of renal tubular inflammation and injury after renal IR. Our proposal also aims to identify novel therapies to protect against ischemic AKI.

由于缺血和再灌注（IR）引起的急性肾脏损伤（AKI）是主要未解决的临床问题 极高的死亡率和医疗保健费用，缺血性AKI经常使主要血管复杂化， 心脏和肝脏手术。尽管肾小管炎症是缺血性AKI的主要机制，但 没有有效的疗法来限制肾脏IR损伤施加生效时期后的炎症反应 临床护理。肽基精氨酸脱氨酶-4（PAD4）催化精氨酸的翻译后转化 citrullline。我们最近的小说发现表明，肾脏近端细胞不仅表达功能 PAD4此外，肾脏IR损伤还增加了小鼠肾小管PAD4的表达和活性。 此外，药物PAD4抑制或遗传PAD4缺失显着降低了肾小管 IR后炎症（细胞因子/趋化因子表达和中性粒细胞浸润）和损伤。相比之下， 重组人PAD4蛋白加剧了IR后的肾小管注射和损伤。但是， 肾脏IR后PAD4诱导的机制，肾脏中的细胞类型发生PAD4诱导发生 以及肾脏PAD4激活产生的下游细胞信号传导事件尚不清楚。 令人兴奋的初步数据表明，细胞外ATP及其类似物会诱导肾脏近端结节细胞 PAD4通过激活P2X7受体。这是非常重要的，因为最近的研究表明细胞外ATP IR后，由坏死细胞释放，进一步促进注射和细胞死亡。我们的初步数据 提示PAD4柠檬磷脂并增加肾近端管的活性 IKBα激酶γ（IKKγ也 被称为NFKB必需调节剂或NEMO），可通过核NFKB诱导促炎性细胞因子 易位。此外，我们的初步研究表明，阻止NEMO激活可以预防 重组PAD4诱导的小鼠缺血性AKI加重。 基于这些初步数据，我们 中心假设是细胞外ATP介导的肾近端管状PAD4加剧的诱导 IR后通过增强的Nemo柠檬硫化和激活后的肾脏炎症和损伤。此外，我们 假设抑制肾小管红色黑色疾病激活可预防肾脏损伤和注射 ir。我们将利用体内（鼠肾脏IR）和体外（近端小管细胞）模型进一步阐明 通过测试以下3个特定目的，该机制并发现缺血性AKI的潜在疗法。 目标＃1：确定肾细胞类型并确定缺血性AKI后PAD4诱导的机理。 目标＃2：阐明缺血性AKI后PAD4介导的肾脏注射的机制。 AIM＃3：通过选择性靶向近端小管Nemo来开发缺血性AKI的新疗法。 总而言之，我们的翻译方法将提供对肾脏机制的新了解 肾脏IR后的管状感染和损伤。我们的建议还旨在确定保护的新疗法 反对缺血性AKI。