Klotho: Therapeutic Agent for Ischemia Reperfusion Induced Acute Kidney Injury

Klotho：缺血再灌注引起的急性肾损伤的治疗剂

• 批准号: 9307141
• 负责人: Ming-Chang Hu
• 金额: $ 36.45万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-17 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9307141
• 关键词: Acute; Acute Renal Failure with Renal Papillary Necrosis; Affect; Aging; Autophagocytosis; Benign; Biology; Blood Vessels; Blood capillaries; Catabolic Process; Cell Line; Cell physiology; Cells; Chronic Kidney Failure; Cleaved cell; Collagen; Data; Disease Progression; End stage renal failure; Endothelial Cells; Etiology; Extracellular Domain; Fibrosis; Functional Magnetic Resonance Imaging; Future; Genetic; High Resolution Computed Tomography; Histology; Human; Hyperactive behavior; Impairment; In Vitro; Injury; Ischemia; Kidney; Lead; Literature; Measurement; Membrane; Mesenchymal; Morbidity - disease rate; Mus; Outcome; Pathologic Processes; Pathway interactions; Patients; Pharmacology; Prevention; Recovery; Reperfusion Therapy; Reporter; Risk; Rodent; Testing; Therapeutic; Therapeutic Agents; Tubular formation; Up-Regulation; angiogenesis; attenuation; base; blood perfusion; capillary; driving force; effective therapy; glomerulosclerosis; improved; in vivo; kidney cell; kidney vascular structure; mortality; mutant; novel; novel strategies; pre-clinical; prevent; receptor

Project Summary/Abstract Acute kidney injury (AKI) confers high morbidity and mortality. Even though patients survive, there is a substantial risk of progression to chronic kidney disease (CKD). Unfortunately, there is no effective therapy to retard this progression. Klotho (here referred as Klotho) was shown to effectively block this transition. But, whether Klotho’s renoprotection involves prevention of vascular rarefaction and whether the suppressive effect of Klotho on renal fibrosis is associated with the clearance of collagen are largely unknown. Abnormal autophagy may lead to renal tubular and vascular damage, and renal fibrosis. Vascular rarefaction and renal fibrosis contribute to CKD. Klotho deficiency is associated with impaired angiogenesis. But, it is unclear whether Klotho can rescue peritubular capillaries in AKI. Klotho was found to upregulate autophagy, improve revascularization, and promote collagen I degradation in vitro; but, how Klotho affects autophagy and if this effect modulates vascular rarefaction and fibrosis, and prevents progression to CKD needs to be defined. The central hypothesis is that Klotho prevents AKI transition to CKD by promoting autophagy, which in turn inhibits renal fibrosis and ameliorates vascular rarefaction. There are three specific aims to test this hypothesis. Aim 1 investigates if Klotho increases autophagy flux in the kidney by (1) examining if Klotho upregulates renal autophagy flux in LC3 reporter mice; (2) defining the mechanisms of upregulation of autophagy by Klotho in vivo; (3) exploring how Klotho regulates autophagy flux in kidney cell line. Aim 2 examines if Klotho inhibits renal fibrosis via upregulation of autophagy activity by (1) examining if Klotho upregulates autophagy and inhibits renal fibrosis post-IRI; (2) defining if autophagy levels influence renal fibrosis post-AKI using mice with low or high autophagy activity; (3) investigating how autophagy reduces collagen I or promotes the degradation of collagen I in GFP-collagen I transfected cells in vitro. Aim 3 explores if Klotho ameliorates vascular rarefaction via upregulation of autophagy in endothelial cells post-AKI by (1) examining if Klotho restores peritubular capillaries with structural analysis (histology and high resolution CT), and measurement of renal blood perfusion and oxygenation (functional MRI, fMRI); (2) testing if Klotho blocks endothelial-mesenchymal transition in AKI mice with endothelial tracing markers; (3) confirming if Klotho protects endothelial damage and endothelial-mesenchymal transition in cultured endothelial cells via modulation of autophagy. Aim 1 focuses on basic biology of Klotho effect on autophagy, which builds the basis for other two independent but scientifically interconnected Aims. This renewed proposal was built based on previous 5-year studies and will provide more evidence to support the concept that Klotho upregulates autophagy to inhibit fibrosis, ameliorates rarefaction after AKI and retards AKI-to-CKD progression. Developing new approaches to enhance renal vascular recovery and inhibit fibrosis is the translational objective of the proposal. Bringing Klotho to a therapeutic platform in human AKI is in the proximal future.

项目总结/摘要 急性肾损伤（阿基）具有较高的发病率和死亡率。即使病人存活下来， 进展为慢性肾脏疾病（CKD）的重大风险。不幸的是，没有有效的治疗方法， 延缓这一进程。Klotho（这里称为Klotho）被证明可以有效地阻止这种转变。但是， Klotho的肾保护作用是否包括预防血管稀疏，以及抑制作用是否 Klotho对肾纤维化的影响与胶原蛋白的清除有关，这在很大程度上是未知的。 异常的自噬可导致肾小管和血管的损害，以及肾纤维化。血管稀疏 和肾纤维化导致CKD。Klotho缺乏症与血管生成受损相关。但却 目前尚不清楚Klotho是否可以挽救阿基中的小管周围毛细血管。Klotho被发现上调自噬， 改善血管再生，并促进体外胶原I降解;但是，Klotho如何影响自噬， 如果这种作用调节血管稀疏和纤维化，并防止进展为CKD，需要明确。 中心假设是Klotho通过促进自噬来防止阿基向CKD的转变， 抑制肾纤维化和改善血管稀疏。有三个具体目标来检验这一假设。 目的1研究Klotho是否增加肾脏中的自噬通量，通过（1）检查Klotho是否上调肾脏自噬通量， （2）确定Klotho在LC 3报告小鼠中上调自噬的机制; （3）探讨Klotho对肾细胞自噬流的调控机制。目的2检查Klotho是否抑制 通过（1）检查Klotho是否上调自噬， 抑制IRI后肾纤维化;（2）使用具有以下特征的小鼠定义自噬水平是否影响AKI后肾纤维化： 低或高的自噬活性;（3）研究自噬如何减少胶原I或促进降解 GFP-Ⅰ型胶原转染细胞中Ⅰ型胶原的表达。目的3探讨Klotho是否改善血管 AKI后通过上调内皮细胞中的自噬来使细胞稀疏，通过（1）检查Klotho是否恢复 肾小管周围毛细血管的结构分析（组织学和高分辨率CT），以及肾 血液灌注和氧合（功能性MRI，fMRI）;（2）测试Klotho是否阻断内皮-间质细胞 （3）确认Klotho是否保护内皮损伤， 通过调节自噬在培养的内皮细胞中进行内皮-间充质转化。 目的1着重于Klotho对自噬作用的基础生物学研究，为其他两个独立的研究奠定基础。 但科学上相互关联的目标这一更新的建议是基于以前的5年研究， 将提供更多的证据来支持Klotho上调自噬以抑制纤维化的概念， 改善阿基后的稀疏并延缓AKI至CKD的进展。制定新的方法， 恢复肾血管和抑制纤维化是该提案的翻译目标。把克洛托带到一个 在人类阿基的治疗平台是在不久的将来。