Sachs Marlies, Wetzel Sebastian, Reichelt Julia, Sachs Wiebke, Schebsdat Lisa, Zielinski Stephanie, Seipold Lisa, Heintz Lukas, Müller Stephan A, Kretz Oliver, Lindenmeyer Maja, Wiech Thorsten, Huber Tobias B, Lüllmann-Rauch Renate, Lichtenthaler Stefan F, Saftig Paul, Meyer-Schwesinger Catherine
Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Institute of Biochemistry, Christian-Albrechts University Kiel, Kiel, Germany.
J Am Soc Nephrol. 2021 Jun 1;32(6):1389-1408. doi: 10.1681/ASN.2020081213. Epub 2021 Mar 30.
Podocytes embrace the glomerular capillaries with foot processes, which are interconnected by a specialized adherens junction to ultimately form the filtration barrier. Altered adhesion and loss are common features of podocyte injury, which could be mediated by shedding of cell-adhesion molecules through the regulated activity of cell surface-expressed proteases. A Disintegrin and Metalloproteinase 10 (ADAM10) is such a protease known to mediate ectodomain shedding of adhesion molecules, among others. Here we evaluate the involvement of ADAM10 in the process of antibody-induced podocyte injury.
Membrane proteomics, immunoblotting, high-resolution microscopy, and immunogold electron microscopy were used to analyze human and murine podocyte ADAM10 expression in health and kidney injury. The functionality of ADAM10 ectodomain shedding for podocyte development and injury was analyzed, and , in the anti-podocyte nephritis (APN) model in podocyte-specific, ADAM10-deficient mice.
ADAM10 is selectively localized at foot processes of murine podocytes and its expression is dispensable for podocyte development. Podocyte ADAM10 expression is induced in the setting of antibody-mediated injury in humans and mice. Podocyte ADAM10 deficiency attenuates the clinical course of APN and preserves the morphologic integrity of podocytes, despite subepithelial immune-deposit formation. Functionally, ADAM10-related ectodomain shedding results in cleavage of the cell-adhesion proteins N- and P-cadherin, thus decreasing their injury-related surface levels. This favors podocyte loss and the activation of downstream signaling events through the Wnt signaling pathway in an ADAM10-dependent manner.
ADAM10-mediated ectodomain shedding of injury-related cadherins drives podocyte injury.
足细胞通过足突包绕肾小球毛细血管，足突通过一种特殊的黏附连接相互连接，最终形成滤过屏障。黏附改变和丢失是足细胞损伤的常见特征，这可能是由细胞表面表达的蛋白酶的调节活性导致细胞黏附分子脱落所介导的。解整合素和金属蛋白酶10（ADAM10）就是这样一种已知可介导黏附分子胞外域脱落的蛋白酶。在此，我们评估ADAM10在抗体诱导的足细胞损伤过程中的作用。
采用膜蛋白质组学、免疫印迹、高分辨率显微镜和免疫金电子显微镜分析健康和肾损伤状态下人及小鼠足细胞中ADAM10的表达。在足细胞特异性ADAM10缺陷小鼠的抗足细胞肾炎（APN）模型中，分析ADAM10胞外域脱落对足细胞发育和损伤的功能。
ADAM10选择性定位于小鼠足细胞的足突，其表达对于足细胞发育并非必需。在人和小鼠抗体介导的损伤情况下，足细胞ADAM10表达被诱导。尽管有上皮下免疫沉积物形成，但足细胞ADAM10缺陷可减轻APN的临床病程并保留足细胞的形态完整性。在功能上，ADAM10相关的胞外域脱落导致细胞黏附蛋白N-钙黏蛋白和P-钙黏蛋白的裂解，从而降低其与损伤相关的表面水平。这有利于足细胞丢失，并以ADAM10依赖的方式通过Wnt信号通路激活下游信号事件。
ADAM10介导的与损伤相关的钙黏蛋白胞外域脱落驱动足细胞损伤。
