STEM CELL THERAPY FOR ACUTE KIDNEY INJURY

描述（由申请人提供）：急性肾损伤（AKI）具有很高的发病率和死亡率。目前唯一可用于AKI的治疗包括支持措施。该项目的总体目标是开发基于干细胞的治疗AKI的方法。我们之前已经证明，新鲜分离的小鼠造血干细胞（HSC）可以移植并纳入再生肾小管。然而，掺入率很低，没有观察到功能效益。为了增强造血干细胞的治疗潜力，我们开发了一种新的方法，在移植前用细胞因子、肾源性因子和HDAC抑制剂trichostatin a依次处理造血干细胞和祖细胞，以诱导肾分化。诱导细胞重新表达肾发育基因和下调造血分化基因。注射诱导细胞或诱导细胞条件培养基可改善AKI小鼠的肾功能，提示内分泌/旁分泌作用对肾脏有保护作用。此外，在诱导细胞上阻断钙感应受体（CaR）会增加细胞的肾定位。这一结果表明，CaR的调节可能有助于增加细胞的肾内递送，以获得更大的治疗效果。为了扩展这些有希望的发现，我们建议用额外的肾脏标志物来表征诱导细胞，以确认肾细胞命运的选择。我们将通过体外实验和移植研究来确定诱导细胞是否能分化为功能性肾上皮细胞。将分析参与细胞转化的分子途径，以指导发现细胞转化的最佳条件（目的1）。我们将研究诱导细胞是否通过减少内源性小管上皮细胞和/或内皮细胞的死亡和增加增殖来发挥内分泌/旁分泌作用。由于存活的肾小管细胞是肾脏修复的主要来源，诱导细胞释放的肾营养因子可能是治疗AKI的重要药物（Aim 2）。此外，我们将用抗体阻断CaR或使用CaR缺陷小鼠来测试CaR的调节是否会增加细胞的肾内转运。这一策略可以通过增加肾小管整合来直接替代细胞，并为受损小管提供更持久的肾营养因子递送，从而增加诱导细胞的治疗效用（目的3）。总之，我们采用新方法开发细胞治疗剂，通过顺序治疗造血干细胞和祖细胞来治疗AKI，这些干细胞和祖细胞可以很容易地用于供体定向治疗。公共卫生相关性：叙述性急性肾损伤具有高发病率和高死亡率。目前尚无具体有效的治疗方法。干细胞为肾脏疾病提供了治疗潜力。本应用的目标是开发基于干细胞的治疗急性肾损伤的方法。

DESCRIPTION (provided by applicant): Acute kidney injury (AKI) carries high morbidity and mortality. The only treatment that is currently available for AKI consists of supportive measures. The overall goal of this project is to develop stem cell- based therapy to treat AKI. We have previously shown that freshly isolated mouse hematopoietic stem cells (HSC) can be transplanted and incorporated into regenerating renal tubules. However, the incorporation rate is low and no functional benefit is observed. To enhance the therapeutic potential of HSC, we have developed a novel approach in which hematopoietic stem and progenitor cells are treated sequentially with cytokines, nephrogenic factors, and an HDAC inhibitor trichostatin A to induce renal differentiation prior to transplantation. Induced cells have de novo expression of renal developmental genes and down-regulation of hematopoietic differentiation genes. Injection of induced cells or induced cell-conditioned medium improves renal function in mice with AKI, suggesting renal protection by endocrine/paracrine effects. Furthermore, blocking the calcium sensing receptor, CaR, on induced cells increases renal localization of the cells. This result suggests that modulation of the CaR may be useful to increase intrarenal delivery of the cells to achieve greater therapeutic effects. To extend these promising findings, we propose to characterize induced cells with additional renal markers to confirm the selection of renal cell fate. We will determine whether induced cells can differentiate into functional renal epithelial cells by in vitro assays and transplantation studies. The molecular pathways involved in cell conversion will be analyzed to guide the discovery of optimal conditions for cell conversion (Aim 1). We will examine whether induced cells exert endocrine/paracrine effects by decreasing death and increasing proliferation of endogenous tubular epithelial cells and/or endothelial cells. Since surviving tubular cells are the main source for renal repair, renotrophic factors released by induced cells can be important agents to treat AKI (Aim 2). Furthermore, we will block the CaR with an antibody or use CaR-deficient mice to test whether modulation of the CaR could increase intrarenal transmigration of the cells. This strategy may increase the therapeutic utility of induced cells by increasing tubular integration for direct cell replacement and providing more sustained delivery of renotrophic factors to the injured tubules (Aim 3). In conclusion, we take novel approaches to develop cell therapeutic agents to treat AKI by sequential treatment of hematopoietic stem and progenitor cells that can be obtained easily for donor-directed therapy. PUBLIC HEALTH RELEVANCE: Narrative Acute kidney injury has high morbidity and high mortality. There is no specific and effective treatment at present time. Stem cells offer therapeutic potential for kidney disease. The goal of this application is to develop stem cell-based therapy to treat acute kidney injury.