Cysteine-rich angiogenic inducer 61 as a tool to efficiently enrich myeloid angiogenic cells from peripheral blood

Introduction Circulating precursor cell populations with putative functions in tissue regeneration have a great potential for cell based regenerative strategies. We have previously shown that cysteine-rich angiogenic inducer 61 (CYR61) coating enriches angiogenic precursor cells from peripheral blood. This study aimed to in-depth characterize the enriched cell population and to profile their putative regenerative potential.

Methods We here compared peripheral blood mononuclear cells enriched by CYR61 to cells obtained by fibronectin coating by means of flow cytometry, gene expression profiling and functional assays.

Results We found that the CYR61 enriched cell populations harbor features of both early endothelial progenitor cells and the monocyte macrophage lineage but rather represent myeloid angiogenic cells (MACs). This is supported by RNAseq data and flow cytometry analysis of surface marker expression and acLDL-uptake, revealing a characteristic CD11b-LDL+MAC population. Following cells up for longer culture times in different culture set-ups, we confirmed monocyte/macrophage-specific features and the ability of cells to differentiate towards multinucleated osteoclast-like cells. Matrigel angiogenic network formation assays indicated that MACs do not by themselves build networks but support and participate in angiogenic networks, established by e.g. HUVEC cells. Interestingly, co-cultured CYR61-enriched MACs and their supernatants inhibit mineralization of primary skeletal precursor cells (MSC) during in vitro osteogenic differentiation protocols, which might be associated with a high abundance of osteopontin in MACs.

Discussion In conclusion, Cyr61-enriches a myeloid angiogenic cell population with significantly higher cell yields compared to conventional fibronectin coating. Our analyses revealed that MACs have a great potential to differentiate towards the macrophage / osteoclast lineage as well as support the formation of angiogenic networks in vitro, while they suppress osteogenic differentiation of co-cultured MSCs and these functions were associated with secretion of high levels of osteopontin. These characteristics render the CYR61-enriched cell population as an autologous source with the potential to modulate tissue regeneration. In addition, these cells might also be a versatile predictive tool of certain individual regeneration capacities. CYR61 protein coating may be an effective tool to enrich regenerative proangiogenic cell populations from peripheral blood.

Keywords Angiogenesis, Regeneration, Myeloid cells

Korrespondenzadresse Marietta Herrmann, Universitätsklinikum Würzburg, IZKF Group Tissue Regeneration in Musculoskeletal Diseases, Röntgenring 11, 97070 Würzburg, Deutschland, E-Mail: [e-mail]

Publication History

Article published online:
08 September 2022