Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles(ULB), Brussels, Belgium.
Elife. 2021 Sep 17;10:e67670. doi: 10.7554/eLife.67670.
Cilia are sensory organelles protruding from cell surfaces. Release of extracellular vesicles (EVs) from cilia was previously observed in mammals, , and in male . Using the EV marker TSP-6 (an ortholog of mammalian CD9) and other ciliary receptors, we show that EVs are formed from ciliated sensory neurons in hermaphrodites. Release of EVs is observed from two ciliary locations: the cilia tip and/or periciliary membrane compartment (PCMC). Outward budding of EVs from the cilia tip leads to their release into the environment. EVs' budding from the PCMC is concomitantly phagocytosed by the associated glial cells. To maintain cilia composition, a tight regulation of cargo import and removal is achieved by the action of intra-flagellar transport (IFT). Unbalanced IFT due to cargo overexpression or mutations in the IFT machinery leads to local accumulation of ciliary proteins. Disposal of excess ciliary proteins via EVs reduces their local accumulation and exports them to the environment and/or to the glia associated to these ciliated neurons. We suggest that EV budding from cilia subcompartments acts as a safeguard mechanism to remove deleterious excess of ciliary material.
纤毛是从细胞表面伸出的感觉器官。先前在哺乳动物中观察到细胞纤毛释放细胞外囊泡（EVs）， 在雄性 中也观察到了这一点。我们使用 EV 标记物 TSP-6（哺乳动物 CD9 的同源物）和其他纤毛受体，证明 EV 是由雌雄同体的感觉神经元的纤毛形成的。EV 的释放发生在两个纤毛位置：纤毛尖端和/或纤毛旁膜区室（PCMC）。从纤毛尖端向外突出的 EV 导致它们释放到环境中。从 PCMC 出芽的 EV 同时被相关的神经胶质细胞吞噬。为了维持纤毛的组成，通过内纤毛运输（IFT）的作用实现了货物摄取和去除的紧密调节。由于货物过表达或 IFT 机制中的突变导致 IFT 不平衡，会导致纤毛蛋白在局部积累。通过 EV 去除多余的纤毛蛋白可以减少其在局部的积累，并将其输出到环境中和/或输出到与这些有纤毛的神经元相关的神经胶质细胞中。我们认为，从纤毛亚区室出芽的 EV 作为一种保护机制，可以去除多余的有害纤毛物质。
