The role of maladaptive VEGFR2 signaling in renal stroma for chronic kidney disease

项目总结/摘要 急性肾损伤（阿基）的一个可怕后果是发展为慢性肾脏疾病的风险急剧增加 （CKD）。CKD占医疗费用的6.7%。了解阿基进展的机制 对于开发目前尚不存在的治疗方法至关重要。肾脏微血管系统，包括 在阿基中，周细胞和内皮细胞受损，导致炎性细胞的募集， 有助于CKD的进展。然而，驱动这一过程的细胞和分子机制是 大部分未知。周细胞是一种异质性间充质细胞群， 肌成纤维细胞的来源，驱动CKD。了解介导适应不良的分子机制 内皮-周细胞串扰导致炎症加重和延长， 利用这种现象。以前，已经表明，血管的全身阻断 内皮生长因子受体2（VEGF-R2）阻断CKD进展。我的初步数据， 包括周细胞的肾基质来源细胞（RSC）中的VegfR 2（称为VegfR 2 RSC-/-）证实了VEGFR 2在肾基质来源细胞（RSC）中的表达。 这种功能丧失的保护性质。发现在CKD模型中，肾缺血/再灌注损伤（IRI） VegfR 2 RSC-/-小鼠沿着减轻CKD进展， 炎症和保存的血管功能。我对分离的RSC进行的批量RNA测序分析 表明炎症途径被激活，而短链脂肪酸代谢途径被激活。 在AKI向CKD转变期间受到抑制。在机制上，VegfR 2 RSC-/-肾（1）具有减少的VEGFR 2 RSC-/-表达。 血小板反应蛋白-1（TSP 1）/CD 148的促炎信号传导轴，和（2）具有增加的 脂肪酸代谢相关基因有助于增强保护。为了准确把握 为了保护，我已经产生了他莫昔芬诱导的RSC特异性VegfR 2敲除（iVegfR 2 RSC-/-）小鼠。我发现 在他莫昔芬预处理后，iVegfR 2 RSC-/-小鼠显著地免受阿基。所有这些 这些数据告诉我，肾周细胞特异性VEGF-R2信号转导失调周细胞的总体假设， 内皮串扰刺激炎症，加重CKD。我提出以下目标来检验这一点： 1将检验周细胞特异性VEGF-R2信号传导加剧AKI向CKD转变的假设。目标2将 测试周细胞VEGF-R2信号转导介导周细胞-内皮细胞串扰适应不良的假设， 加剧炎症，促进AKI到CKD。目的3将检验抑制VegfR 2信号传导 在肾周细胞中，增强血管修复，减轻炎症，并阻断阿基后向CKD的进展。 为了K 01奖，我招募了创新导师。匹兹堡大学拥有数量惊人的 研究项目主要集中在阿基和血管医学。成功完成这些 研究将阐明肾周细胞特异性VEGF-R2信号传导如何加剧CKD进展。

PROJECT SUMMARY/ ABSTRACT A dire consequence of acute kidney injury (AKI) is a dramatically increased risk to develop chronic kidney disease (CKD). CKD accounts for 6.7% of Medicare expenses. Understanding the mechanisms by which AKI progresses to CKD is essential for developing therapies, for which none currently exist. Renal microvasculature, including pericytes and endothelial cells, are damaged in AKI, leading to recruitment of inflammatory cells which contributes to progression to CKD. However, cellular, and molecular mechanisms that drive this process are largely unknown. Pericytes are a heterogeneous mesenchymal population and have been identified as a major source of myofibroblasts that drives CKD. Understanding the molecular mechanisms that mediates maladaptive endothelial-pericyte crosstalk leading to exacerbated and prolonged inflammation could drive therapeutic exploitation of this phenomenon. Previously, it has been shown that the systemic blockade of Vascular endothelial growth factor receptor 2 (VEGF-R2) blocks CKD progression. My preliminary data, knocking out VegfR2 in renal stromally derived cells (RSC) (termed VegfR2RSC-/-) that includes pericytes, confirms the protective nature of this loss-of-function. I found that, in CKD models by renal ischemia/ reperfusion injury (IRI) as well as by cisplatin, VegfR2RSC-/- mice have attenuated CKD progression, along with having mitigated inflammation and preserved vascular function. My bulk RNA-sequencing analysis with isolated RSCs demonstrates that inflammatory pathways are activated while short-chain fatty acid metabolism pathways are suppressed during AKI-to-CKD transition. Mechanistically, VegfR2RSC-/- kidneys (1) have reduced expression of a pro-inflammatory signaling axis of Thrombospondin-1 (TSP1)/ CD148, and (2) have increased expression of fatty acid metabolism associated genes contributing to the enhanced protection. To home in on the timing of the protection, I have generated a tamoxifen-inducible RSC-specific VegfR2 knockout (iVegfR2RSC-/-) mouse. I found that, after pre-treatment of tamoxifen, iVegfR2RSC-/- mice are significantly protected against AKI. Together, these data informed my overarching hypothesis that renal pericyte-specific VEGF-R2 signaling dysregulates pericyte- endothelial crosstalk stimulating inflammation to exacerbate CKD. I propose the following aims to test this: Aim 1 will test the hypothesis that pericyte-specific VEGF-R2 signaling exacerbates AKI-to-CKD transition. Aim 2 will test the hypothesis that pericyte VEGF-R2 signaling mediates maladaptive pericyte-endothelial crosstalk to exacerbate inflammation, promoting AKI-to-CKD. Aim 3 will test the hypothesis that inhibiting VegfR2 signaling in renal pericytes enhances vascular repair, mitigates inflammation, and blocks progression to CKD after AKI. For the K01 Award, I enlisted innovative mentors. The University of Pittsburgh has an extraordinary number of faculty with research programs focused on AKI, and on vascular medicine. Successful completion of these studies will shed light on how renal pericyte specific VEGF-R2 signaling exacerbates CKD progression.