Osmanagic-Myers Selma, Rus Stefanie, Wolfram Michael, Brunner Daniela, Goldmann Wolfgang H, Bonakdar Navid, Fischer Irmgard, Reipert Siegfried, Zuzuarregui Aurora, Walko Gernot, Wiche Gerhard
Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria.
Department of Physics, Friedrich-Alexander-University of Erlangen-Nuremberg, 91052 Erlangen, Germany.
J Cell Sci. 2015 Nov 15;128(22):4138-50. doi: 10.1242/jcs.172056. Epub 2015 Oct 30.
Mutations in the cytoskeletal linker protein plectin result in multisystemic diseases affecting skin and muscle with indications of additional vascular system involvement. To study the mechanisms underlying vascular disorders, we established plectin-deficient endothelial cell and mouse models. We show that apart from perturbing the vimentin cytoskeleton of endothelial cells, plectin deficiency leads to severe distortions of adherens junctions (AJs), as well as tight junctions, accompanied by an upregulation of actin stress fibres and increased cellular contractility. Plectin-deficient endothelial cell layers were more leaky and showed reduced mechanical resilience in fluid-shear stress and mechanical stretch experiments. We suggest that the distorted AJs and upregulated actin stress fibres in plectin-deficient cells are rooted in perturbations of the vimentin cytoskeleton, as similar phenotypes could be mimicked in wild-type cells by disruption of vimentin filaments. In vivo studies in endothelium-restricted conditional plectin-knockout mice revealed significant distortions of AJs in stress-prone aortic arch regions and increased pulmonary vascular leakage. Our study opens a new perspective on cytoskeleton-controlled vascular permeability, where a plectin-organized vimentin scaffold keeps actomyosin contractility 'in-check' and maintains AJ homeostasis.
细胞骨架连接蛋白网蛋白的突变会导致影响皮肤和肌肉的多系统疾病，并伴有血管系统受累的迹象。为了研究血管疾病的潜在机制，我们建立了网蛋白缺陷的内皮细胞和小鼠模型。我们发现，除了扰乱内皮细胞的波形蛋白细胞骨架外，网蛋白缺乏还会导致黏附连接（AJs）以及紧密连接的严重扭曲，同时伴有肌动蛋白应力纤维的上调和细胞收缩性的增加。在流体剪切应力和机械拉伸实验中，网蛋白缺陷的内皮细胞层更易渗漏，且机械弹性降低。我们认为，网蛋白缺陷细胞中AJs的扭曲和肌动蛋白应力纤维的上调源于波形蛋白细胞骨架的扰动，因为在野生型细胞中破坏波形蛋白丝可模拟出类似的表型。在内皮细胞特异性条件性网蛋白敲除小鼠中的体内研究显示，在易受应力影响的主动脉弓区域，AJs出现明显扭曲，肺血管渗漏增加。我们的研究为细胞骨架控制的血管通透性开辟了一个新视角，即由网蛋白组织的波形蛋白支架可控制肌动球蛋白的收缩性并维持AJ的稳态。
