Hybrid Hydrogels for Harnessing Mesenchymal Stem Cell Secretome

Abstract

The low engraftment and retention rate of mesenchymal stem cells (MSCs) at the target site indicates that the potential benefits of MSC-based therapies can be attributed to their paracrine signaling. In this study, the influence of decellularized extracellular matrices (dECM) on pro-angiogenic signaling of MSC was investigated. Effect of cell passage number on ECM secretion and subsequently, on regulation of MSC secretome was also explored. The study revealed upregulated expression of angiogenesis-related factors upon culturing MSCs on dECMs irrespective of media supplementation. In addition, dECM generated in presence of ascorbic acid promoted expression of angiogenic molecules as compared to dECM derived in absence of media supplementation. Further, it was observed that the effectiveness of dECM to stimulate angiogenic signaling of MSCswas reduced as cell passage number was increased from P3 to P5. The activity of MSC-secreted biomolecules investigated by assessing the proliferation as well as capillary morphogenesis of human umbilical vein endothelial cells (HUVECs) supported the Proteome Profiler data. Working towards the goal of creating a biomaterial capable of recapitulating the multifactorial aspects of the stem cell environment, ECM deposited by MSCs was collected and introduced into alginate solution to create a hybrid material. Alginate concentration was varied while keeping the dECM concentration constant. Swelling ratio, degradation and diffusion of the hybrid hydrogels were explored in comparison to dECM-free (alginate only) gels. Results found that both degradation and diffusion characteristics were impacted by the introduction of matrix proteins. Lastly, the printability of the hybrid hydrogels at various printing pressures was also explored using Cellink’s INKREDIBLE bioprinter. Optimal printing pressures for each bioink composition was explored, and it was revealed that dECM addition improved the bioink’s printability at lower printing pressures in comparison to dECM-free gels.