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

项目摘要/摘要 急性肾损伤(AKI)的一个可怕后果是患慢性肾脏疾病的风险急剧增加。 (CKD)。CKD占联邦医疗保险费用的6.7%。了解AKI的发展机制 对慢性肾脏病的治疗是开发治疗方法的关键，目前还没有治疗方法。肾微血管系统，包括 周细胞和内皮细胞，在AKI中受到破坏，导致炎症细胞的募集，从而 有助于进展为CKD。然而，驱动这一过程的细胞和分子机制是 很大程度上是未知的。周细胞是一种异质性间充质细胞群，已被确定为主要的 驱动慢性肾脏病的肌成纤维细胞的来源。理解调节适应不良的分子机制 内皮-周细胞串扰导致炎症加剧和持续可能推动治疗 对这种现象的利用。此前，已有研究表明，血管的系统性阻断 内皮生长因子受体2(VEGF-R2)可阻断CKD的进展。我的初步数据，被淘汰了 在包括周细胞的肾基质来源细胞(RSC)(称为VegfR2RSC-/-)中，VEGFR2证实了 这种功能丧失的保护性。我发现，在肾缺血/再灌注损伤(IRI)所致的CKD模型中， 与顺铂一样，VegfR2RSC-/-小鼠也减缓了CKD的进展，同时缓解了 炎症和保存的血管功能。用分离的RSCs进行My Bulk 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到CKD转换期间被抑制。从机制上讲，VegfR2RSC-/-肾脏(1)减少了 血栓反应蛋白-1(TSP1)/CD148的促炎信号轴，以及(2)增加了 与脂肪酸代谢相关的基因有助于增强保护。充分了解这一事件的时间安排 保护，我已经产生了三苯氧胺诱导的RSC特异性VEGFR2基因敲除(iVegfR2RSC-/-)小鼠。我发现 在他莫昔芬的预治疗后，iVegfR2RSC-/-小鼠对AKI具有显著的保护作用。加在一起，这些 数据告诉我的总体假设，肾脏周细胞特异性的血管内皮生长因子-R2信号失调周细胞- 内皮串扰刺激炎症加重CKD。我提出以下目标来检验这一点：目标 1将检验这样的假设，即周细胞特异性的VEGF-R2信号加剧了AKI到CKD的转变。目标2将 验证周细胞血管内皮生长因子-R2信号介导周细胞-内皮细胞不适应串扰的假说 加剧炎症，促进AKI到CKD。目标3将测试抑制VEGFR2信号转导的假设 肾周细胞可增强血管修复，减轻炎症，阻止AKI后进展为CKD。 对于K01奖，我招募了创新导师。匹兹堡大学拥有数量惊人的 拥有专注于AKI和血管医学的研究项目的教职员工。成功完成这些任务 研究将阐明肾周细胞特异性的血管内皮生长因子-R2信号如何加剧CKD的进展。

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.