Secretome Comparison of Mesenchymal Stromal Cells and Immature Osteoblasts

Osteoblasts are a key component of the endosteal hematopoietic stem cell (HSC) niche and have long been recognized with strong hematopoietic supporting activity. Osteoblast conditioned media (OCM) enhances the growth of hematopoietic progenitors in culture and modulate their engraftment activity. We aimed to characterize the hematopoietic supporting activity of OCM by comparing the secretome of immature osteoblasts to that of their precursor, mesenchymal stromal cells (MSC). Over 300 secreted proteins were quantified by mass spectroscopy in media conditioned with MSC or osteoblasts, with 47 being differentially expressed.