Autocrine fibroblast growth factor 2-mediated interactions between human mesenchymal stem cells and the extracellular matrix under varying oxygen tension

Human mesenchymal stromal or stem cells (hMSCs) are being investigated for cell therapy in a wide range of diseases. MSCs are a potent source of trophic factors and actively remodel their immediate microenvironment through the secretion of bioactive factors in response to external stimuli such as oxygen tension. In this study, we examined the hypothesis that hypoxia influences hMSC properties in part through the regulation of extracellular milieu characterized by the extracellular matrix (ECM) matrices and the associated fibroblast growth factor-2 (FGF-2). The decellularized ECM matrices derived from hMSC culture under both hypoxic (e.g., 2% O2) and the standard culture (e.g., 20% O2) conditions have different binding capacities to the cell-secreted and exogenenous FGF-2. The reduced hMSC proliferation in the presence of FGF-2 inhibitor and the differential capacity of the decellularized ECM matrices in regulating hMSC osteogeneic and adipogenic differentiation suggest an important role of the endogenous FGF-2 in sustaining hMSC proliferation and regulating hMSC fate. Additionally, the combination of the ECM adhesion and hypoxic culture preserved hMSC viability under serum withdrawal. Together, the results suggest the synergistic effect of hypoxia and the ECM matrices in sustaining hMSC ex vivo expansion and preserving their multi-potentiality and viability under nutrient depletion. The results have important implication in optimizing hMSC expansion and delivery strategies to obtain hMSCs in sufficient quantity with required potency and to enhance survival and function upon transplantation. J. Cell. Biochem. 114: 716727, 2013. (C) 2012 Wiley Periodicals, Inc.