Targeting Renal Tubular Epithelial Progenitors in AKI to CKD transition

项目概要/摘要 肾修复/再生失调导致急性肾功能衰竭后发生慢性肾病（CKD）。 肾损伤（阿基）。然而，没有有效的治疗方法来改善肾修复/再生过程， 缺乏治疗选择使受影响的患者处于CKD进展和CKD的高风险中- 相关的心血管事件和死亡率。这种未满足的医疗需求强调了以下方面的重要性： 通过阐明受损肾修复的分子基础来确定新的治疗策略。高度 最近，再生的表达SRY-盒9（SOX 9）的肾小管上皮细胞（以下称为Sox 9祖细胞）被 被鉴定为健康肾修复的关键细胞群。我们发现Sox 9-祖细胞成为 功能障碍，在严重但非轻度阿基后失去再生功能。我们大量的初步数据 进一步表明过量的氧化应激通过以下途径导致Sox 9-祖细胞的功能障碍： 铁凋亡是一种新发现的氧化应激诱导的非凋亡调节性细胞死亡， 在人类阿基中观察到。我们的初步数据还强调了利用抗- 铁蛋白防御途径，以增强肾上皮修复和避免进展为CKD。然而，在这方面， 氧化应激诱导的Sox 9-祖细胞功能障碍的分子机制仍然未知， 铁凋亡对AKI向CKD转变的作用需要阐明。为了推进这一有前途的， 临床相关的调查线，我们将测试我们的中心假设，即：（1）在设置严重的管状 阿基中的氧化应激，Sox 9-祖细胞变得功能障碍，阻碍肾修复/再生，和（2） Sox 9-祖细胞中过量的脂质过氧化诱导铁凋亡，妨碍受损肾的健康愈合 肾小管，从而推动进展为CKD。为了验证这些假设，我们将整合无偏单细胞 转录组学和小鼠遗传学在两个特定的目的。在目标1中，我们将确定Sox 9- 通过对肾脏进行比较分析， 轻度缺血性肾损伤。在目标2中，我们将研究Sox 9-祖细胞中的铁凋亡作为关键驱动因素， 通过基因删除抗铁蛋白防御酶谷胱甘肽的AKI向CKD转变的机制 过氧化物酶4，来自Sox 9-祖细胞。我们将对我们的基因修饰小鼠品系进行缺血性，毒性， 梗阻性肾损伤，以确定在整个范围内Sox 9-祖细胞的铁凋亡的贡献。 不同的阿基病因。这些目标的完成将使我们能够确定适应不良的分子机制 肾修复和阐明肾小管上皮祖细胞铁凋亡的基本致病作用。 我们的研究结果将为激活抗氧化和抗铁代谢途径以增强 肾修复/再生作为破坏AKI向CKD转变的新疗法。

Project Summary/Abstract Dysregulated renal repair/regeneration leads to the development of chronic kidney disease (CKD) after acute kidney injury (AKI). However, there are no effective treatments to improve the renal repair/regeneration process, and the dearth of therapeutic options leaves affected patients at high risk of CKD progression and CKD- associated cardiovascular events and mortality. This unmet medical need underscores the importance of identifying new therapeutic strategies by elucidating the molecular underpinnings of impaired renal repair. Highly regenerative SRY-box 9 (SOX9)-expressing tubular epithelial cells (hereafter, Sox9-progenitors) were recently identified as a critical cell population for healthy renal repair. We found that Sox9-progenitors become dysfunctional, losing their regenerative function after severe but not mild AKI. Our extensive preliminary data further indicate that excess oxidative stress contributes to the dysfunction of Sox9-progenitors through ferroptosis, a newly identified form of oxidative-stress-induced, non-apoptotic regulated cell death that is observed in human AKI. Our preliminary data also underscore the therapeutic potential of harnessing anti- ferroptotic defense pathways to enhance renal epithelial repair and avert progression to CKD. However, molecular mechanisms underlying oxidative stress-induced Sox9-progenitor dysfunction remain unknown, and the contribution of ferroptosis to the AKI-to-CKD transition requires elucidation. To advance this promising and clinically relevant line of investigation, we will test our central hypotheses that: (1) In the setting of severe tubular oxidative stress in AKI, Sox9-progenitors become dysfunctional, impeding renal repair/regeneration, and (2) excess lipid-peroxidation in Sox9-progenitors induces ferroptosis, precluding healthy healing of damaged renal tubules, thus driving progression to CKD. To test these hypotheses, we will integrate unbiased single-cell transcriptomics and mouse genetics in two Specific Aims. In Aim 1, we will determine the mechanisms of Sox9- progenitor dysfunction at single-cell resolution by comparative analyses of kidneys that underwent severe versus mild ischemic renal injuries. In Aim 2, we will investigate ferroptosis in Sox9-progenitors as a key driving mechanism of the AKI-to-CKD transition by genetically deleting the anti-ferroptotic defense enzyme, glutathione peroxidase 4, from the Sox9-progenitors. We will subject our gene-modified mouse lines to ischemic, toxic, and obstructive renal injuries to define the contribution of ferroptosis of Sox9-progenitors across the spectrum of different AKI etiologies. Completion of these aims will allow us to identify molecular mechanisms of maladaptive renal repair and elucidate the fundamental pathogenic roles of ferroptosis in renal tubular epithelial progenitors. Our results will lay the scientific foundation for activating anti-oxidative and anti-ferroptotic pathways to enhance renal repair/regeneration as a novel therapy to disrupt the AKI-to-CKD transition.