The C-terminal domain of chondroadherin: A new regulator of osteoclast motility counteracting bone loss

Mattia Capulli, Ole K. Olstad, Patrik Önnerfjord, Viveka Tillgren, Maurizio Muraca, Kaare M. Gautvik, Nadia Rucci, Anna Teti

Research output: Contribution to journalArticle

Abstract

Chondroadherin (CHAD) is a leucine-rich protein promoting cell attachment through binding to integrin α2β1 and syndecans. We observed that CHAD mRNA and protein were lower in bone biopsies of 50-year-old to 65-year-old osteoporotic women and in bone samples of ovariectomized mice versus gender/age-matched controls, suggesting a role in bone metabolism. By the means of an internal cyclic peptide (cyclicCHAD), we observed that its integrin binding sequence impaired preosteoclast migration through a nitric oxide synthase 2-dependent mechanism, decreasing osteoclastogenesis and bone resorption in a concentration-dependent fashion, whereas it had no effect on osteoblasts. Consistently, cyclicCHAD reduced transcription of two nitric oxide downstream genes, migfilin and vasp, involved in cell motility. Furthermore, the nitric oxide donor, S-nitroso-N-acetyl-D,L- penicillamine, stimulated preosteoclast migration and prevented the inhibitory effect of cyclicCHAD. Conversely, the nitric oxide synthase 2 (NOS2) inhibitor, N5-(1-iminoethyl)-l-ornithine, decreased both preosteoclast migration and differentiation, confirming a role of the nitric oxide pathway in the mechanism of action triggered by cyclicCHAD. In vivo, administration of cyclicCHAD was well tolerated and increased bone volume in healthy mice, with no adverse effect. In ovariectomized mice cyclicCHAD improved bone mass by both a preventive and a curative treatment protocol, with an effect in line with that of the bisphosphonate alendronate, that was mimicked by the NOS2 inhibitor [L-N6-(1-Iminoethyl)-lysine.2 dihydrochloride]. In both mouse models, cyclicCHAD reduced osteoclast and bone resorption without affecting osteoblast parameters and bone formation. In conclusion, CHAD is a novel regulator of bone metabolism that, through its integrin binding domain, inhibits preosteoclast motility and bone resorption, with a potential translational impact for the treatment of osteoporosis.

Original languageEnglish
Pages (from-to)1833-1846
Number of pages14
JournalJournal of Bone and Mineral Research
Volume29
Issue number8
DOIs
Publication statusPublished - 2014

Keywords

  • Chondroadherin
  • Osteoclasts
  • Osteoporosis

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Endocrinology, Diabetes and Metabolism
  • Medicine(all)

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  • Cite this

    Capulli, M., Olstad, O. K., Önnerfjord, P., Tillgren, V., Muraca, M., Gautvik, K. M., Rucci, N., & Teti, A. (2014). The C-terminal domain of chondroadherin: A new regulator of osteoclast motility counteracting bone loss. Journal of Bone and Mineral Research, 29(8), 1833-1846. https://doi.org/10.1002/jbmr.2206