(162aa) The Effect of Heparin/Collagen Layer-By-Layer Coating in Immunomodulatory Functions of Mesenchymal Stromal/Stem Cells Stimulated By IFN-?

Human mesenchymal stromal cells (hMSCs) are multipotent cells that have been proposed for the treatment of immune-mediated diseases. The immunosuppressive properties of hMSCs can be enhanced using interferon‐gamma (IFN‐γ); however, pretreatment with IFN‐γ decreases hMSC proliferation. In this study, multilayers of heparin and collagen (HEP/COL) were used as a bioactive surface coating to reduce the effects of IFN‐γ on hMSCs while enhancing the secretion of critical immunomodulatory cytokines. Multilayers were formed, via layer-by-layer assembly, varying the final layer between COL and HEP and supplemented with IFN-γ in the culture medium. hMSC adhesion, proliferation, differentiation, and cytokine expression were assessed. The activation of hMSCs by soluble IFN‐γ was evaluated by measuring the level of indoleamine 2,3-dioxygenase (IDO) secretion. The possibility of inducing hMSCs to differentiate into osteoblasts and adipocytes was measured by exposing them to differentiation media specific to each lineage after IFN‐γ treatment. We confirmed differentiation by staining using Alizarin Red (osteoblasts), and Oil-red O (adipocytes). We performed quartz crystal microbalance (QCM) experiments to evaluate in situ the adhesion of IFN‐γ to COL/HEP films. Lastly, we measure cytokine expression of hMSCs cultured on HEP/COL films in the presence or absence of IFN‐γ using a Luminex assay. This study shows that HEP/COL films can modulate hMSC response to soluble factors, which may improve hMSCs-based therapies aimed at treating several immune diseases.