Shota Kawaguchi, Taiga Ajiri, Rina Mitsuya, Reiko Tsuchiya, Koki Kunitake, Y. Tanaka, Takeshi Yokoyama, Kiichi Sato, Yusuke Sato, Zetao Zhu, Kunanon Chattrairat, Yasuko Kobayashi, Kimiko Inoue, Keisuke Imaeda, Kosei Ueno, Sou Ryuzaki, Akira Kato, Yasuyuki Kimura, Atsushi Natsume, Ryosuke Kojima, Takao Yasui
Urinary small extracellular vesicles (sEVs), which can reflect systemic conditions, hold great promise for noninvasive cancer diagnostics, yet the mechanism by which tumor-derived sEVs reach urine remains unclear. Here, we demonstrate that the glomerulus actively transcytoses circulating tumor-derived sEVs into urine. Using CRISPR guide RNA-tagged glioma sEVs and bioluminescent/fluorescent green-enhanced nano-lantern (GeNL)-tagged lung and pancreatic cancer sEVs, we tracked their journey from tumors to urine in multiple mouse models. In vivo and in vitro analyses revealed endocytic uptake and transcytotic release by glomerular cells, accompanied by changes in sEV size and surface composition. GeNL-tagged sEVs consistently showed higher signals in urine than plasma, indicating selective excretion. These findings redefine the glomerulus as a dynamic regulator of sEV processing and establish a mechanistic foundation for urinary liquid biopsy.