Spontaneous In Vivo Chondrogenesis of Bone Marrow‐Derived Mesenchymal Progenitor Cells by Blocking Vascular Endothelial Growth Factor Signaling

• Published in: Stem cells translational medicine Vol. 5; no. 12; pp. 1730 - 1738
• Main Authors: Marsano, Anna, Medeiros da Cunha, Carolina M., Ghanaati, Shahram, Gueven, Sinan, Centola, Matteo, Tsaryk, Roman, Barbeck, Mike, Stuedle, Chiara, Barbero, Andrea, Helmrich, Uta, Schaeren, Stefan, Kirkpatrick, James C., Banfi, Andrea, Martin, Ivan
• Format: Journal Article
• Language: English
• Published: Durham, NC, USA AlphaMed Press 01.12.2016; Oxford University Press
• Subjects: Adult; Angiogenesis; Bone marrow; Bone Marrow Cells - cytology; Bone Marrow Cells - drug effects; Bone Marrow Cells - metabolism; Cartilage; Cell Differentiation - drug effects; Cell Proliferation - drug effects; Chondrogenesis; Chondrogenesis - drug effects; Data analysis; Endothelial Cells - cytology; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Enzymes; Female; Humans; Hypertrophy; Hypoxia; Laboratory animals; Male; Mesenchymal Stromal Cells - cytology; Mesenchymal Stromal Cells - drug effects; Mesenchymal Stromal Cells - metabolism; Mesenchymal stromal/stem cells; Mesenchyme; Neovascularization, Physiologic - drug effects; Osteoprogenitor cells; Oxygen - pharmacology; Phenotypes; Progenitor cells; Signal Transduction - drug effects; Stem cell transplantation; Stem cells; Tissue Engineering and Regenerative Medicine; Transduction, Genetic; Transforming Growth Factor beta - metabolism; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; Vascular endothelial growth factor blockade; Vascular Endothelial Growth Factor Receptor-2 - metabolism; Young Adult; Hypoxia; Chondrogenesis; Mesenchymal stromal/stem cells; Vascular endothelial growth factor blockade
• DOI: 10.5966/sctm.2015-0321
• ISSN: 2157-6564

This study assessed whether simple inhibition of angiogenesis by vascular endothelial growth factor (VEGF) blockade is sufficient to direct in vivo chondrogenic differentiation of implanted human mesenchymal stromal/stem cells (MSCs). MSCs transduced to express sFlk‐1 and directly implanted subcutaneously in nude mice without in vitro preculture spontaneously differentiated into the chondrocytic lineage with a stable phenotype for the observation time‐period of 12 weeks. These findings suggest that VEGF blockade is a robust strategy to enhance cartilage repair by endogenous or grafted mesenchymal progenitors. Acknowledgements Chondrogenic differentiation of bone marrow‐derived mesenchymal stromal/stem cells (MSCs) can be induced by presenting morphogenetic factors or soluble signals but typically suffers from limited efficiency, reproducibility across primary batches, and maintenance of phenotypic stability. Considering the avascular and hypoxic milieu of articular cartilage, we hypothesized that sole inhibition of angiogenesis can provide physiological cues to direct in vivo differentiation of uncommitted MSCs to stable cartilage formation. Human MSCs were retrovirally transduced to express a decoy soluble vascular endothelial growth factor (VEGF) receptor‐2 (sFlk1), which efficiently sequesters endogenous VEGF in vivo, seeded on collagen sponges and immediately implanted ectopically in nude mice. Although naïve cells formed vascularized fibrous tissue, sFlk1‐MSCs abolished vascular ingrowth into engineered constructs, which efficiently and reproducibly developed into hyaline cartilage. The generated cartilage was phenotypically stable and showed no sign of hypertrophic evolution up to 12 weeks. In vitro analyses indicated that spontaneous chondrogenic differentiation by blockade of angiogenesis was related to the generation of a hypoxic environment, in turn activating the transforming growth factor‐β pathway. These findings suggest that VEGF blockade is a robust strategy to enhance cartilage repair by endogenous or grafted mesenchymal progenitors. This article outlines the general paradigm of controlling the fate of implanted stem/progenitor cells by engineering their ability to establish specific microenvironmental conditions rather than directly providing individual morphogenic cues. Chondrogenic differentiation of mesenchymal stromal/stem cells (MSCs) is typically targeted by morphogen delivery, which is often associated with limited efficiency, stability, and robustness. This article proposes a strategy to engineer MSCs with the capacity to establish specific microenvironmental conditions, supporting their own targeted differentiation program. Sole blockade of angiogenesis mediated by transduction for sFlk‐1, without delivery of additional morphogens, is sufficient for inducing MSC chondrogenic differentiation. The findings represent a relevant step forward in the field because the method allowed reducing interdonor variability in MSC differentiation efficiency and, importantly, onset of a stable, nonhypertrophic chondrocyte phenotype.