Understanding Epithelial Plasticity in Renal Repair after Acute Kidney Injury

了解急性肾损伤后肾脏修复中的上皮可塑性

• 批准号: 10188520
• 负责人: Sanjeev Kumar
• 金额: $ 39.81万
• 依托单位: CEDARS-SINAI 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: 2018-08-21 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10188520
• 关键词: Acute; Acute Renal Failure with Renal Papillary Necrosis; Adult; Automobile Driving; Brush Border; Cancer cell line; Cell Nucleus; Cell Proliferation; Cells; Chronic Kidney Failure; Cicatrix; Coupled; Coupling; DNA Binding; DNA Repair; Data; Development; Disease model; Dissection; Embryo; Epidermal Growth Factor Receptor; Epithelial; Epithelial Cell Proliferation; Epithelial Cells; Gene Expression Profiling; Genes; Genetic; Genetic Transcription; Goals; Health; Hepatocyte; Hospitals; Human; In Vitro; Injury; Injury to Kidney; Kidney; Kidney Failure; Link; Malignant Neoplasms; Mediator of activation protein; Methodology; Molecular; Morbidity - disease rate; Mus; Myofibroblast; Natural regeneration; Nephrons; Nuclear; Pathologic; Pathway interactions; Patients; Play; Process; Proliferating; Protein Tyrosine Kinase; Recovery of Function; Regulation; Renal function; Reporting; Research; Risk; Role; Signal Transduction; Survivors; Syncope; Testing; Tissues; Tubular formation; Work; base; body system; cell type; comparative; conditional knockout; direct application; epithelial injury; epithelial repair; epithelium regeneration; gain of function; genome-wide; in vivo; inhibitor/antagonist; injured; injury and repair; innovation; insight; loss of function; mortality; nephron progenitor; novel; progenitor; regenerative; repair model; repaired; reparative process; response; response to injury; therapy development; tissue repair

Understanding Epithelial Plasticity in Renal Repair after Acute Kidney Injury Following acute kidney injury (AKI), surviving tubular epithelial cells (TECs) proliferate and regenerate the injured epithelium leading to kidney function recovery. However, until recently, the intrinsic molecular driver of epithelial regeneration remained elusive. To this end, we recently identified SOX9 as the molecular driver that regenerates the injured epithelium. Coupling genetic lineage strategy to tissue-specific, conditional knock-out methodology, we identified SOX9 as a direct, intrinsic molecular link between repair and formation of the nephron tubular epithelia. Upon successful regeneration of the epithelia after injury, SOX9 attained baseline level. However, during progression of ischemic AKI to chronic kidney disease (CKD), distinct, sporadic persistently injured TECs mounted a strong sustained SOX9 (sSOX9+) with cell proliferation signature thereby demarcating “unresolved injury/repair cell-type”. These findings raise crucial unanswered questions, including: (1) does human kidneys activate SOX9 after AKI, (2) how an injured epithelium rapidly mounts a SOX9 pro- replicative response, (3) how SOX9 drive epithelial regeneration and whether upon activation it dedifferentiates the injured TECs to its embryonic progenitor-like state to drive repair, and (4) whether sSOX9+ contributes to the progression of AKI to CKD. To this end, here we further identify (a) SOX9 activation after human AKI, (b) a nuclear phosphoEGFR:SOX9 pro-replicative axis in both primary mice and human proximal TECs, and (c) intimate, robust association of sSOX9+ cells with αSMA+ myofibroblasts. The proposed research will test (Aim 1) the hypothesis that injury induced EGFR signaling via nuclear phosphorylated EGFR activates Sox9 and exerts Sox9-dependent pro-reparative effects, with Sox9 per se being sufficient to drive proliferation; (Aim 2) will reveal molecular underpinnings of Sox9-orchestrated reparative action whilst determining whether injury- activated Sox9 dedifferentiates the injured PTECs to a progenitor-like state; (Aim 3) test the hypothesis that sustained Sox9+ subset demarcating “unresolved injury/repair” cell-type contribute to progression of AKI to CKD. The proposed research is innovative because using state-of-the-art approaches we will critically investigate the above heretofore-unexamined molecular and cellular pathways in renal repair. The proposed research is significant and impactful because (A) our findings akin to our mice studies highlight SOX9 activation within the PTECs after human ischemic AKI and SOX9-based pro-replicative responses in human primary proximal tubular epithelial cells; and (B) injury-induced epithelial plasticity is a poorly understood process, and deep, critical insights gained by the proposed research work will advance not only kidney field but will have direct application to the mechanistic understanding of tissue remodeling in other epithelial-based organ systems. Better understanding of such processes is crucial in the development of therapies aimed to harness and augment endogenous reparative processes while simultaneously blocking pro-fibrotic responses.

了解急性肾损伤后肾脏修复中的上皮可塑性 急性肾损伤 (AKI) 后，存活的肾小管上皮细胞 (TEC) 增殖并再生 受损的上皮导致肾功能恢复。然而，直到最近，内在的分子驱动因素 上皮再生仍然难以捉摸。为此，我们最近确定 SOX9 作为分子驱动因素 使受损的上皮细胞再生。将遗传谱系策略与组织特异性、条件性敲除相结合 根据方法论，我们确定 SOX9 是修复和形成之间直接的、内在的分子联系。 肾单位管状上皮。损伤后上皮细胞成功再生后，SOX9 达到基线 等级。然而，在缺血性 AKI 进展为慢性肾脏病 (CKD) 的过程中，明显的、散发性的 持续损伤的 TEC 上存在强大的持续 SOX9 (sSOX9+)，从而具有细胞增殖特征 划分“未解决的损伤/修复细胞类型”。这些发现提出了一些尚未解答的关键问题，包括： (1) AKI 后人类肾脏是否会激活 SOX9，(2) 受损的上皮细胞如何快速启动 SOX9 亲 复制反应，(3) SOX9 如何驱动上皮再生以及激活后是否去分化 受损的 TEC 恢复其胚胎祖细胞状态以驱动修复，以及 (4) sSOX9+ 是否有助于 AKI 进展为 CKD。为此，我们在这里进一步确定了 (a) 人类 AKI 后 SOX9 的激活，(b) 原代小鼠和人类近端 TEC 中的核磷酸化 EGFR:SOX9 促复制轴，以及 (c) sSOX9+ 细胞与 αSMA+ 肌成纤维细胞密切、牢固的关联。拟议的研究将测试（目标 1) 损伤通过核磷酸化 EGFR 激活 Sox9 诱导 EGFR 信号转导的假设 发挥 Sox9 依赖性的促修复作用，Sox9 本身足以驱动增殖； （目标2） 将揭示 Sox9 精心策划的修复作用的分子基础，同时确定损伤是否 激活的 Sox9 使受损的 PTEC 去分化至祖细胞样状态； （目标 3）检验假设 持续的 Sox9+ 子集划分“未解决的损伤/修复”细胞类型有助于 AKI 进展为 慢性肾病。拟议的研究是创新的，因为使用最先进的方法，我们将批判性地 研究上述迄今为止未经检验的肾脏修复分子和细胞途径。拟议的 研究意义重大且有影响力，因为 (A) 我们与小鼠研究类似的发现突出了 SOX9 人类缺血性 AKI 和基于 SOX9 的促复制反应后 PTEC 内的激活 原代近端肾小管上皮细胞； (B) 损伤引起的上皮可塑性尚不清楚 拟议的研究工作所获得的过程和深刻、关键的见解不仅将推动肾脏领域的发展，而且将推动肾脏领域的发展。 将直接应用于其他基于上皮的组织重塑的机制理解 器官系统。更好地理解这些过程对于开发旨在治疗的疗法至关重要 利用并增强内源性修复过程，同时阻止促纤维化反应。