Purpose/Aim of the study. Collagen type XV (ColXV) was identified, in our previews studies, as a novel component of bone extracellular matrix. The present study aims to investigate ColXV localization during mineralization of osteodifferentiated human mesenchymal stem cells (hMSCs).
Material and methods: hMSCs cultured in osteogenic medium have been analyzed at day 14 and 28 for mineral matrix deposition by alizarin red S staining, ultrastructural analysis and ColXV localization by immunogold electron microscopy.
Results: Our data show an intimate association between ColXV and fibrillar components in areas localized far from mineralized nodules.
Conclusions: We have demonstrated the efficacy of ultrastructural analysis, combined with immunocytochemistry, to establish a temporal and spatial localization of ColXV. This data, added to previous evidences, contribute to validate the negative effects of calcium deposits on ColXV expression.
Keywords: Collagen type XV; Human mesenchymal stem cells; immunogold; mineralization; osteogenesis.