Ultrastructural analysis of apatite-degrading capability of extended invasive podosomes in resorbing osteoclasts
| Autor: | Toshitaka Akisaka, Astushi Yoshida |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Podosome Invadopodium General Physics and Astronomy Osteoclasts Matrix (biology) Filamentous actin Cell Membrane Structures Apatite 03 medical and health sciences 0302 clinical medicine Structural Biology Cell Movement Apatites Extracellular Cell Adhesion Animals Replica Techniques General Materials Science Bone Resorption Cells Cultured Microscopy Chemistry Cell migration Cell Biology Anatomy Actin Cytoskeleton 030104 developmental biology visual_art Podosomes Biophysics Ultrastructure visual_art.visual_art_medium Rabbits 030217 neurology & neurosurgery |
| Zdroj: | Micron (Oxford, England : 1993). 88 |
| ISSN: | 1878-4291 |
| Popis: | Osteoclasts in culture are non-transformed cell types that spontaneously develop specific cell-adhesion devices such as podosomes. An individual podosome is a complex network of filamentous actin (F-actin) unit structure that collectively, with other proteins, self-organizes as the sealing zone. Major matrix degradation on apatite seems to proceed under the ruffled-border domain, which is an enclosed extracellular compartment tightly sealed off by this sealing zone. Presently we found that usually the top of finger-like projections of the ruffled border reached toward the plane of the apatite surface, where a shallow degradation of apatite took place. Simultaneously, we obtained several pieces of structural evidence indicating that a specific protrusion referred to as an invasive podosome (invadopodium), which was continuous with podosomes derived from the sealing zone, invaded deeply into apatite matrix and degraded it. The F-actin architecture of the invasive podosome – an active extracellular matrix-degrading, actin-rich cell protrusion – could be distinguished from that of other punctate F-actin structures including the individual podosome, sealing zone, and ruffled border projection. Invasive podosomes contained 2 different F-actin populations, i.e., an interconnected meshwork and a parallel array of bundles. The morphological variability of these protrusions was apparent, having a single cylindrical to lamella-shaped cytoskeletal organization. Our present observations strongly suggest that the degradation of apatite substrate-resorbing osteoclasts appears to have been preceded by the combined appearance of ruffled border and invasive podosomes, and also occurred simultaneously with cell migration during an alternating cycle of resorption and migration. |
| Databáze: | OpenAIRE |
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