Experimental Nephrology, Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
Core Facility Cellular Imaging (CFCI), Medical Faculty Carl Gustav Carus, Technical University Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
Pflugers Arch. 2019 Sep;471(9):1205-1217. doi: 10.1007/s00424-019-02298-9. Epub 2019 Aug 6.
Synthesis of renin in renal renin-producing cells (RPCs) is controlled via the intracellular messenger cAMP. Interference with cAMP-mediated signaling by inducible knockout of Gs-alpha (Gsα) in RPCs of adult mice resulted in a complex adverse kidney phenotype. Therein, glomerular endothelial damage was most striking. In this study, we investigated whether Gsα knockout leads to a loss of RPCs, which itself may contribute to the endothelial injury. We compared the kidney phenotype of three RPC-specific conditional mouse lines during continuous induction of recombination. Mice expressing red fluorescent reporter protein tdTomato (tdT) in RPCs served as controls. tdT was also expressed in RPCs of the other two strains used, namely with RPC-specific Gsα knockout (Gsα mice) or with RPC-specific diphtheria toxin A expression (DTA mice, in which the RPCs should be diminished). Using immunohistological analysis, we found that RPCs decreased by 82% in the kidneys of Gsα mice as compared with controls. However, the number of tdT-positive cells was similar in the two strains, demonstrating that after Gsα knockout, the RPCs persist as renin-negative descendants. In contrast, both renin-positive and tdT-labeled cells decreased by 80% in DTA mice suggesting effective RPC ablation. Only Gsα mice displayed dysregulated endothelial cell marker expression indicating glomerular endothelial damage. In addition, a robust induction of genes involved in tissue remodelling with microvascular damage was identified in tdT-labeled RPCs isolated from Gsα mice. We concluded that Gsα/renin double-negative RPC progeny essentially contributes for the development of glomerular endothelial damage in our Gsα-deficient mice.
肾素产生细胞（RPCs）中的 renin 合成受细胞内信使 cAMP 控制。在成年小鼠的 RPC 中诱导敲除 Gsα（Gsα）以干扰 cAMP 介导的信号转导，导致复杂的肾脏不良表型。其中，肾小球内皮损伤最为明显。在这项研究中，我们研究了 Gsα 敲除是否导致 RPC 丢失，而这种丢失本身可能导致内皮损伤。我们比较了三种在持续诱导重组过程中具有条件性的 RPC 特异性小鼠系的肾脏表型。在 RPC 中表达红色荧光报告蛋白 tdTomato（tdT）的小鼠作为对照。另外两种使用的菌株（即具有 RPC 特异性 Gsα 敲除的 Gsα 小鼠或具有 RPC 特异性白喉毒素 A 表达的 DTA 小鼠）的 tdT 也在 RPC 中表达，在这些小鼠中，RPC 应该减少。通过免疫组织化学分析，我们发现与对照组相比，Gsα 小鼠肾脏中的 RPC 减少了 82%。然而，两种菌株中 tdT 阳性细胞的数量相似，表明 Gsα 敲除后，RPC 作为 renin 阴性后代持续存在。相比之下，在 DTA 小鼠中，既减少了 renin 阳性和 tdT 标记的细胞 80%，表明有效消融了 RPC。只有 Gsα 小鼠显示出失调的内皮细胞标记物表达，表明肾小球内皮损伤。此外，在从 Gsα 小鼠分离的 tdT 标记的 RPC 中，还鉴定出与组织重塑和微血管损伤相关的基因的强烈诱导。我们得出结论，Gsα/renin 双阴性 RPC 后代对于我们的 Gsα 缺陷小鼠中肾小球内皮损伤的发展起着重要作用。
