PTX3 Effects on Osteogenic Differentiation in Osteoporosis: An In Vitro Study

Pentraxin 3 (PTX3) is a glycoprotein belonging to the humoral arm of innate immunity that participates in the body’s defence mechanisms against infectious diseases. It has recently been defined as a multifunctional protein, given its involvement in numerous physiological and pathological processes, as well as in the pathogenesis of age-related diseases such as osteoporosis. Based on this evidence, the aim of our study was to investigate the possible role of PTX3 in both the osteoblastic differentiation and calcification process: to this end, primary osteoblast cultures from control and osteoporotic patients were incubated with human recombinant PTX3 (hrPTX3) for 72 h. Standard osteinduction treatment, consisting of β-glycerophosphate, dexamethasone and ascorbic acid, was used as control. Our results showed that treatment with hrPTX3, as well as with the osteogenic cocktail, induced cell differentiation towards the osteoblastic lineage. We also observed that the treatment not only promoted an increase in cell proliferation, but also the formation of calcification-like structures, especially in primary cultures from osteoporotic patients. In conclusion, the results reported here suggest the involvement of PTX3 in osteogenic differentiation, highlighting its osteoinductive capacity, like the standard osteoinduction treatment. Therefore, this study opens new and exciting perspectives about the possible role of PTX3 as biomarker and therapeutic agent for osteoporosis.