Human Osteoclasts/Osteoblasts 3D Dynamic Co-Culture System to Study the Beneficial Effects of Glucosamine on Bone Microenvironment

Abstract

Background: Glucosamine (GlcN) functions as a building block of the cartilage matrix and its multifaceted roles in promoting joint health has been extensively investigated. On the contrary, the role of GlcN in osteogenesis and bone tissue is poorly understood, mainly due to the lack of adequate experimental models. Consequently, the benefit of GlcN in bone disorders remains controversial. In order to broaden the pharmacological relevance and potential therapeutic/nutraceutic efficacy of GlcN, we investigated the effect of GlcN on human primary osteoclasts (hOCs) and osteoblasts (hOBs) that were grown with 2D traditional methods or co-cultured in a more complex culture system one step closer to the in vivo bone microenvironment, consisting in a three-dimensional (3D) dynamic system.Methods: Osteoclasts derived from peripheral blood monocytes (hMCs) of either healthy or osteoarthritis (OA) donors, were used and kept in culture with osteoclastogenic inducers. hMCs were also combined with hOBs in a 3D dynamic co‐culture system by using RCCS-4TM bioreactor in osteogenic medium without osteoclastogenic inducers. In this condition osteoclastogenesis was supported by hOBs and sizeable self assembling aggregates were obtained. The differentiated osteoclasts were evaluated by the tartrate-resistant acid phosphatase assay, osteogenic differentiation was monitored by analyzing mineral matrix deposition through Alizarin Red staining, and expression of osteogenic markers through RT-qPCR. The cells were treated with DONA® Crystalline Glucosamine Sulfate (i.e. the original GlcN sulfate product).Results: DONA® was effective in decreasing the hOCs differentiation and function. Osteoclasts from OA donors were more sensitive than those from healthy donors. At the same time, DONA® showed anabolic effects on osteoblasts both in 2D conventional cell culture and in osteoclasts/osteoblasts 3D dynamic co-culture system.Conclusions: Here we demonstrated the effectiveness of a 3D dynamic co-culture system to provide useful information on the spectrum of action of GlcN on bone microenvironment. This can pave the way to better define the potential applications of a compound such as GlcN which is positioned between pharmaceuticals and nutraceuticals. Therefore, based on our observations, we hypothesize that GlcN could have potential benefits either in the treatment of osteopenic diseases such as osteoporosis, or in the bone health maintenance.