Circulating Osteoprogenitor Cells Have a Mixed Immune and Mesenchymal Progenitor Function in Humans.

Abstract

Circulating osteoprogenitors (COP) are a population of cells in the peripheral circulation that possess functional and phenotypical characteristics of multipotent stromal cells (MSCs). This population has a solid potential to become an abundant, accessible, and replenishable source of MSCs with multiple potential clinical applications. However, a comprehensive functional characterization of COP cells is still required to test and fully develop their use in clinical settings. This study characterized COP cells by comparing them to bone marrow-derived MSCs (BM-MSCs) and adipose-derived MSCs (ASCs) through detailed transcriptomic and proteomic analyses. We demonstrate that COP cells have a distinct gene and protein expression pattern with a significantly stronger immune footprint, likely owing to their hematopoietic lineage. In addition, regarding progenitor cell differentiation and proliferation pathways, COP cells have a similar expression pattern to BM-MSCs and ASCs. COP cells are a unique but functionally similar population to BM-MSCs and ASCs, sharing their proliferation and differentiation capacity, thus presenting an accessible source of MSCs with strong potential for translational regenerative medicine strategies.