In Vivo Labeling by CD73 Marks Multipotent Stromal Cells and Highlights Endothelial Heterogeneity in the Bone Marrow Niche

Publication date: 1 February 2018
Source:Cell Stem Cell, Volume 22, Issue 2
Author(s): Martin Breitbach, Kenichi Kimura, Tiago C. Luis, Christopher J. Fuegemann, Petter S. Woll, Michael Hesse, Raffaella Facchini, Sarah Rieck, Katarzyna Jobin, Julia Reinhardt, Osamu Ohneda, Daniela Wenzel, Caroline Geisen, Christian Kurts, Wolfgang Kastenmüller, Michael Hölzel, Sten E.W. Jacobsen, Bernd K. Fleischmann
Despite much work studying ex vivo multipotent stromal cells (MSCs), the identity and characteristics of MSCs in vivo are not well defined. Here, we generated a CD73-EGFP reporter mouse to address these questions and found EGFP⁺ MSCs in various organs. In vivo, EGFP⁺ mesenchymal cells were observed in fetal and adult bones at proliferative ossification sites, while in solid organs EGFP⁺ cells exhibited a perivascular distribution pattern. EGFP⁺ cells from the bone compartment could be clonally expanded ex vivo from single cells and displayed trilineage differentiation potential. Moreover, in the central bone marrow CD73-EGFP⁺ specifically labeled sinusoidal endothelial cells, thought to be a critical component of the hematopoietic stem cell niche. Purification and molecular characterization of this CD73-EGFP⁺ population revealed an endothelial subtype that also displays a mesenchymal signature, highlighting endothelial cell heterogeneity in the marrow. Thus, the CD73-EGFP mouse is a powerful tool for studying MSCs and sinusoidal endothelium.

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Teaser

Breitbach et al. generated a CD73-EGFP reporter mouse that enabled identification and tracking of multipotent stromal cells in vivo. CD73-EGFP also labeled sinusoidal endothelial cells within the bone marrow, enabling the molecular characterization of this important endothelial component of the hematopoietic stem cell niche.


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