title: In vitro model of bone to facilitate measurement of adhesion forces and super-resolution imaging of osteoclasts.
abstract: To elucidate processes in the osteoclastic bone resorption, visualise resorption and related actin reorganisation, a combination of imaging technologies and an applicable in vitro model is needed. Nanosized bone powder from matching species is deposited on any biocompatible surface in order to form a thin, translucent, smooth and elastic representation of injured bone. Osteoclasts cultured on the layer expressed matching morphology to ones cultured on sawed cortical bone slices. Resorption pits were easily identified by reflectance microscopy. The coating allowed actin structures on the bone interface to be visualised with super-resolution microscopy along with a detailed interlinked actin networks and actin branching in conjunction with V-ATPase, dynamin and Arp2/3 at actin patches. Furthermore, we measured the timescale of an adaptive osteoclast adhesion to bone by force spectroscopy experiments on live osteoclasts with bone-coated AFM cantilevers. Utilising the in vitro model and the advanced imaging technologies we localised immunofluorescence signals in respect to bone with high precision and detected resorption at its early stages. Put together, our data supports a cyclic model for resorption in human osteoclasts.
authors.affiliation: Laboratory of Biophysics, Department of Cell Biology and Anatomy and Medicity Research Laboratories, University of Turku, Turku, Finland.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Deguchi
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Turku, Finland.
authors.forename: Maria H
authors.initials: MH
authors.lastname: Alanne
authors.affiliation: Laboratory of Biophysics, Department of Cell Biology and Anatomy and Medicity Research Laboratories, University of Turku, Turku, Finland.
authors.forename: Elnaz
authors.initials: E
authors.lastname: Fazeli
authors.affiliation: Pharmatest Services Ltd, Turku, Finland.
authors.forename: Katja M
authors.initials: KM
authors.lastname: Fagerlund
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Turku, Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Pennanen
authors.affiliation: Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu, Finland.
authors.forename: Petri
authors.initials: P
authors.lastname: Lehenkari
authors.affiliation: Laboratory of Biophysics, Department of Cell Biology and Anatomy and Medicity Research Laboratories, University of Turku, Turku, Finland.
authors.forename: Pekka E
authors.initials: PE
authors.lastname: Hänninen
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Turku, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Peltonen
authors.affiliation: Laboratory of Biophysics, Department of Cell Biology and Anatomy and Medicity Research Laboratories, University of Turku, Turku, Finland.|Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Näreoja
mesh_terms: D001862:Bone Resorption / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D018625:Microscopy, Atomic Force; D008857:Microscopy, Interference; D008954:Models, Biological; D010010:Osteoclasts / Q000378:metabolism* / Q000648:ultrastructure