Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
Curr Biol. 2024 Jun 17;34(12):2756-2763.e2. doi: 10.1016/j.cub.2024.05.015. Epub 2024 Jun 4.
Extracellular vesicles (EVs) are submicron membranous structures and key mediators of intercellular communication. Recent research has highlighted roles for cilia-derived EVs in signal transduction, underscoring their importance as bioactive extracellular organelles containing conserved ciliary signaling proteins. Members of the transient receptor potential (TRP) channel polycystin-2 (PKD-2) family are found in ciliary EVs of the green algae Chlamydomonas and the nematode Caenorhabditis elegans and in EVs in the mouse embryonic node and isolated from human urine. In C. elegans, PKD-2 is expressed in male-specific EV-releasing sensory neurons, which extend ciliary tips to ciliary pore and directly release EVs into the environment. Males release EVs in a mechanically stimulated manner, regulate EV cargo content in response to mating partners, and deposit PKD-2::GFP-labeled EVs on the vulval cuticle of hermaphrodites during mating. Combined, our findings suggest that ciliary EV release is a dynamic process. Herein, we identify mechanisms controlling dynamic EV shedding using time-lapse imaging. Cilia can sustain the release of PKD-2-labeled EVs for 2 h. This extended release doesn't require neuronal transmission. Instead, ciliary intrinsic mechanisms regulate PKD-2 ciliary membrane replenishment and dynamic EV release. The kinesin-3 motor kinesin-like protein 6 (KLP-6) is necessary for initial and extended EV release, while the transition zone protein NPHP-4 is required only for sustained EV release. The dynamic replenishment of PKD-2 at the ciliary tip is key to sustained EV release. Our study provides a comprehensive portrait of real-time ciliary EV release and mechanisms supporting cilia as proficient EV release platforms.
细胞外囊泡 (EVs) 是亚微米膜状结构，是细胞间通讯的关键介质。最近的研究强调了纤毛衍生的 EV 在信号转导中的作用，突出了它们作为含有保守纤毛信号蛋白的生物活性细胞外细胞器的重要性。瞬时受体电位 (TRP) 通道多囊蛋白-2 (PKD-2) 家族的成员存在于绿藻衣藻和线虫秀丽隐杆线虫的纤毛 EV 中，以及在小鼠胚胎节点的 EV 中和从人尿中分离出来的 EV 中。在 C. elegans 中，PKD-2 在雄性特异性 EV 释放感觉神经元中表达，这些神经元延伸纤毛尖端到纤毛孔，并直接将 EV 释放到环境中。雄性以机械刺激的方式释放 EV，响应交配伙伴调节 EV 货物含量，并在交配期间将 PKD-2::GFP 标记的 EV 沉积在雌性的外阴角质层上。综上所述，我们的研究结果表明，纤毛 EV 释放是一个动态过程。在此，我们使用延时成像来鉴定控制动态 EV 脱落的机制。纤毛可以维持 PKD-2 标记的 EV 释放 2 小时。这种延长的释放不需要神经元传递。相反，纤毛内在机制调节 PKD-2 纤毛膜的补充和动态 EV 的释放。驱动蛋白-3 运动相关蛋白 6 (KLP-6) 对于初始和延长的 EV 释放是必需的，而过渡区蛋白 NPHP-4 仅对于持续的 EV 释放是必需的。PKD-2 在纤毛尖端的动态补充是持续 EV 释放的关键。我们的研究提供了实时纤毛 EV 释放和支持纤毛作为高效 EV 释放平台的机制的全面描述。
