Rehman Zia Ur, Obi Ikenna, Nadeem Aftab, Tegtmeyer Nicole, Backert Steffen, Arnqvist Anna
Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.
Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, KUST, Kohat, Pakistan.
J Extracell Vesicles. 2025 Jun;14(6):e70107. doi: 10.1002/jev2.70107.
Extracellular vesicles derived from gram-negative bacteria are nano-sized particles of different size and origin released by these microbes and are collectively called bacterial extracellular vesicles (BEVs). These BEVs may serve as vehicles for delivering bacterial molecules to eukaryotic host cells. Depending on the bacterial species, BEVs elicit various host cellular and immunomodulatory responses, often aiding bacterial survival and communication. Early events in the initial interaction between BEVs and the host cell, as well as how BEVs reach the cell body, remain unexplored. In this study, we describe the interaction of BEVs with actin-rich cellular extensions, including filopodia and retraction fibres, which extend from the host cell surface. Using microscopy-based tracking at the single cell level, BEVs were shown to exploit cellular extensions at the cell periphery to reach the main cell body, either by hijacking retracted extensions or by surfing along these extensions in an actin-dependent manner. BEVs bind to the outer surface of the extensions, but no internalization occurs at this stage. Instead, they serve as transport for BEVs to the main cell body, where endocytosis takes place. Importantly, this process appears to be a general phenomenon for BEVs across different bacterial species and cell origins.
革兰氏阴性菌衍生的细胞外囊泡是由这些微生物释放的不同大小和来源的纳米级颗粒，统称为细菌细胞外囊泡（BEV）。这些BEV可作为将细菌分子递送至真核宿主细胞的载体。根据细菌种类的不同，BEV会引发各种宿主细胞和免疫调节反应，通常有助于细菌的存活和通讯。BEV与宿主细胞之间初始相互作用的早期事件，以及BEV如何到达细胞体，仍有待探索。在本研究中，我们描述了BEV与富含肌动蛋白的细胞突起（包括丝状伪足和收缩纤维）之间的相互作用，这些突起从宿主细胞表面延伸出来。通过单细胞水平的基于显微镜的追踪，发现BEV利用细胞周边的细胞突起到达主要细胞体，其方式要么是劫持缩回的突起，要么是以肌动蛋白依赖的方式沿着这些突起“冲浪”。BEV与突起的外表面结合，但在此阶段不会发生内化。相反，它们作为BEV运输到主要细胞体的载体，在那里发生内吞作用。重要的是，这一过程似乎是不同细菌种类和细胞来源的BEV的普遍现象。
