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Updated: May 8, 2026

Differentiation and Characterization of Osteoclasts from Human Induced Pluripotent Stem Cells
Published on: March 22, 2024
Novel perspectives on the transcytotic route in osteoclasts
Mirkka J Hirvonen1, Katja Fagerlund, Päivi Lakkakorpi
1Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Turku, Finland.
Abstract:
We analyzed the characteristics of degraded bone matrix-delivering vesicles along the transcytotic route from the ruffled border to the functional secretory domain (FSD) in bone-penetrating osteoclasts. Cells of rat or human origin were cultured on bovine bone slices and analyzed via confocal microscopy. Helix pomatia lectin binding indicated that transcytotic vesicles expose aberrant N-acetylgalactosamine glycoconjugates, which is associated with a poor prognosis for a range of metastasizing human adenocarcinomas. Transcytotic vesicles fuse with the autophagosomal compartments and represent raft concentrates. Furthermore, the results of a vertical vesicle analysis suggest that multiple vesicle populations arise from the ruffled border and that some of these vesicles undergo a maturation process along the transcytotic route. Finally, our data suggest that the targeting of these membrane pathways may be determined by a novel F-actin-containing and FSD-circumscribing molecular barrier.
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