Targeting Renal Tubular Epithelial Progenitors in AKI to CKD transition

项目摘要/摘要 急性肾损伤后肾脏修复/再生失调导致慢性肾脏疾病的发展 肾损伤(AKI)。然而，目前还没有有效的治疗方法来改善肾脏修复/再生过程， 治疗选择的缺乏使受影响的患者处于CKD进展和CKD- 相关的心血管事件和死亡率。这一未得到满足的医疗需求强调了 通过阐明受损肾脏修复的分子基础来确定新的治疗策略。高度 表达SRY-box 9(SOX9)的再生肾小管上皮细胞(以下简称SOX9-祖细胞)是近年来发现的 被确认为健康肾脏修复的关键细胞群。我们发现Sox9的祖细胞变成了 功能障碍，在严重但不轻微的AKI后失去再生功能。我们广泛的初步数据 进一步表明，过量的氧化应激通过以下途径导致Sox9-前体功能障碍 铁下垂，一种新发现的氧化应激诱导的非凋亡调节性细胞死亡形式，即 在人类AKI中观察到的。我们的初步数据也强调了利用抗-HBs的治疗潜力 促进肾上皮修复和避免进展为CKD的铁链防御途径。然而， 氧化应激诱导SOX9前体功能障碍的分子机制尚不清楚 铁下垂在AKI到CKD转变中的作用需要阐明。为了推进这一有希望的和 在与临床相关的研究中，我们将检验我们的中心假设：(1)在重度肾小管的情况下 AKI，Sox9-前体细胞的氧化应激功能失调，阻碍肾脏修复/再生，以及(2) Sox9前体细胞过度的脂质过氧化导致铁下垂，阻碍受损肾脏的健康愈合 小管，从而推动进展为CKD。为了检验这些假设，我们将整合无偏的单细胞 转录学和小鼠遗传学有两个特定的目标。在目标1中，我们将确定Sox9的机制- 单细胞分辨率下的祖细胞功能障碍--通过对严重的和非严重的肾脏进行对比分析 轻度缺血性肾损伤。在目标2中，我们将研究Sox9-前体中的铁下垂作为一个关键驱动因素 基因缺失抗铁链防御酶谷胱甘肽的AKI向CKD转变的机制 过氧化物酶4，来自Sox9-前体。我们将使我们的转基因小鼠品系遭受缺血、毒性和 梗阻性肾损伤确定Sox9-前体细胞铁性下垂的作用 不同的AKI病因。这些目标的完成将使我们能够识别适应不良的分子机制 肾修复和阐明铁性下垂在肾小管上皮祖细胞中的基本致病作用。 我们的研究结果将为激活抗氧化和抗铁下垂途径增强 肾脏修复/再生作为阻断AKI向CKD转变的一种新疗法。

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.