Isogai Tatsuki, Hirosawa Koichiro M, Kanno Miki, Sho Ayano, Kasai Rinshi S, Komura Naoko, Ando Hiromune, Furukawa Keiko, Ohmi Yuhsuke, Furukawa Koichi, Yokota Yasunari, Suzuki Kenichi G N
The United Graduate School of Agricultural Science, Gifu University , Gifu, Japan.
Institute for Glyco-core Research (iGCORE), Gifu University , Gifu, Japan.
J Cell Biol. 2025 Jun 2;224(6). doi: 10.1083/jcb.202404064. Epub 2025 Apr 30.
Tumor-derived extracellular vesicles (EVs) have attracted significant attention, yet the molecular mechanisms that govern their specific binding to recipient cells remain elusive. Our in vitro study utilizing single-particle tracking demonstrated that integrin heterodimers comprising α6β4 and α6β1 and ganglioside, GM1, are responsible for the binding of small EV (sEV) subtypes to laminin. EVs derived from four distinct tumor cell lines, regardless of size, exhibited high binding affinities for laminin but not for fibronectin, although fibronectin receptors are abundant in EVs and have functional roles in EV-secreting cells. Our findings revealed that integrins in EVs bind to laminin via the conventional molecular interface, facilitated by CD151 rather than by inside-out signaling of talin-1 and kindlin-2. Super-resolution movie observation revealed that sEV integrins bind only to laminin on living recipient cells. Furthermore, sEVs bound to HUVEC and induced cell branching morphogenesis in a laminin-dependent manner. Thus, we demonstrated that EVs predominantly bind to laminin on recipient cells, which is indispensable for cell responses.
肿瘤衍生的细胞外囊泡（EVs）已引起了广泛关注，但其与受体细胞特异性结合的分子机制仍不清楚。我们利用单粒子追踪技术进行的体外研究表明，由α6β4和α6β1组成的整合素异二聚体以及神经节苷脂GM1负责小细胞外囊泡（sEV）亚型与层粘连蛋白的结合。源自四种不同肿瘤细胞系的EVs，无论大小如何，对层粘连蛋白均表现出高结合亲和力，但对纤连蛋白则不然，尽管纤连蛋白受体在EVs中大量存在且在分泌EVs的细胞中具有功能作用。我们的研究结果表明，EVs中的整合素通过传统分子界面与层粘连蛋白结合，这一过程由CD151促进，而非由踝蛋白-1和纽带蛋白-2的外向内信号传导所介导。超分辨率动态观察显示，sEV整合素仅与活受体细胞上的层粘连蛋白结合。此外，sEVs与人类脐静脉内皮细胞（HUVEC）结合，并以层粘连蛋白依赖的方式诱导细胞分支形态发生。因此，我们证明了EVs主要与受体细胞上的层粘连蛋白结合，这对于细胞反应是必不可少的。
