Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland.
Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
J Biol Chem. 2023 Aug;299(8):104963. doi: 10.1016/j.jbc.2023.104963. Epub 2023 Jun 24.
Vimentin intermediate filaments form part of the cytoskeleton of mesenchymal cells, but under pathological conditions often associated with inflammation, vimentin filaments depolymerize as the result of phosphorylation or citrullination, and vimentin oligomers are secreted or released into the extracellular environment. In the extracellular space, vimentin can bind surfaces of cells and the extracellular matrix, and the interaction between extracellular vimentin and cells can trigger changes in cellular functions, such as activation of fibroblasts to a fibrotic phenotype. The mechanism by which extracellular vimentin binds external cell membranes and whether vimentin alone can act as an adhesive anchor for cells is largely uncharacterized. Here, we show that various cell types (normal and vimentin null fibroblasts, mesenchymal stem cells, and A549 lung carcinoma cells) attach to and spread on polyacrylamide hydrogel substrates covalently linked to vimentin. Using traction force microscopy and spheroid expansion assays, we characterize how different cell types respond to extracellular vimentin. Cell attachment to and spreading on vimentin-coated surfaces is inhibited by hyaluronic acid degrading enzymes, hyaluronic acid synthase inhibitors, soluble heparin or N-acetyl glucosamine, all of which are treatments that have little or no effect on the same cell types binding to collagen-coated hydrogels. These studies highlight the effectiveness of substrate-bound vimentin as a ligand for cells and suggest that carbohydrate structures, including the glycocalyx and glycosylated cell surface proteins that contain N-acetyl glucosamine, form a novel class of adhesion receptors for extracellular vimentin that can either directly support cell adhesion to a substrate or fine-tune the glycocalyx adhesive properties.
波形蛋白中间丝构成间质细胞细胞骨架的一部分,但在与炎症相关的病理条件下,波形蛋白丝由于磷酸化或瓜氨酸化而解聚,并且波形蛋白低聚物被分泌或释放到细胞外环境中。在细胞外空间中,波形蛋白可以与细胞的表面和细胞外基质结合,细胞外波形蛋白与细胞之间的相互作用可以触发细胞功能的变化,例如成纤维细胞向纤维化表型的激活。细胞外波形蛋白结合外部细胞膜的机制以及波形蛋白本身是否可以作为细胞的粘合锚点在很大程度上尚未确定。在这里,我们表明,各种细胞类型(正常和波形蛋白缺失成纤维细胞、间充质干细胞和 A549 肺癌细胞)附着在并在与波形蛋白共价连接的聚丙烯酰胺水凝胶底物上扩展。使用牵引力显微镜和球体扩展测定法,我们描述了不同类型的细胞如何对细胞外波形蛋白做出反应。细胞在涂有波形蛋白的表面上的附着和扩展被透明质酸降解酶、透明质酸合酶抑制剂、可溶性肝素或 N-乙酰氨基葡萄糖抑制,所有这些治疗方法对附着在涂有胶原蛋白的水凝胶上的相同细胞类型几乎没有或没有影响。这些研究强调了与细胞结合的基底结合波形蛋白作为配体的有效性,并表明碳水化合物结构,包括糖萼和含有 N-乙酰氨基葡萄糖的糖基化细胞表面蛋白,形成了细胞外波形蛋白的新型粘附受体类,可直接支持细胞附着到基质上,或微调糖萼的粘附特性。