Osteoclasts secrete osteopontin into resorption lacunae during bone resorption
|Author:||Luukkonen, Jani1; Hilli, Meeri1; Nakamura, Miho1,2;|
1Department of Anatomy and Cell Biology, Cancer Research and Translational Medicine Research Unit, Faculty of Medicine, University of Oulu, Oulu, Finland
2Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
3Thermo Fisher Scientific Oy, Vantaa, Finland
|Online Access:||PDF Full Text (PDF, 3.4 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019061320361
|Publish Date:|| 2019-06-13
Osteopontin (OPN) is a non-collagenous extracellular sialylated glycoprotein located in bone. It is believed to be one of the key components in osteoclast attachment to bone during resorption. In this study, we characterized OPN and other glycoproteins found in the resorption lacunae to confirm the role of osteoclasts in OPN secretion using electron microscopy and mass spectrometry. Additionally, we examined the glycan epitopes of resorption pits and the effects of different glycan epitopes on the differentiation and function of osteoclasts. Osteoarthritic femoral heads were examined by immunohistochemistry to reveal the presence of OPN in areas of increased bone metabolism in vivo. Our results demonstrate that human osteoclasts secrete OPN into resorption lacunae on native human bone and on carbonated hydroxyapatite devoid of natural OPN. OPN is associated with an elevated bone turnover in osteoarthritic bone under experimental conditions. Our data further confirm that osteoclasts secrete OPN into the resorption pit where it may function as a chemokine for subsequent bone formation. We show that α2,3- and α2,6-linked sialic acids have a role in the process of osteoclast differentiation. OPN is one of the proteins that has both of the above sialic residues, hence we propose that de-sialylation can effect osteoclast differentiation in bone.
Histochemistry and cell biology
|Pages:||475 - 487|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
Open access funding provided by University of Oulu including Oulu University Hospital. This work was supported by Northern Ostrobothnia Hospital District Research Funding, The Academy of Finland (130795), MATERA Era-Net program by TEKES, Finland (Scaffolds for Tissue Engineering -project), The National Doctoral Programme of Musculoskeletal Disorders and Biomaterials (TBDP), Grants-in-Aid for the Promotion of Joint International Research (Fostering Joint International Research) (15KK0299) and Grant for Basic Science Research Projects from The Sumitomo Foundation.
|Academy of Finland Grant Number:||
130795 (Academy of Finland Funding decision)
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