Human iPSC-derived mesenchymal stem cells matured into valve interstitial-like cells using PEGDA hydrogels

Publication date: Available online 2 March 2018
Source:Acta Biomaterialia
Author(s): Aline L.Y. Nachlas, Siyi Li, Rajneesh Jha, Monalisa Singh, Chunhui Xu, Michael E. Davis
Despite recent advances in tissue engineered heart valves (TEHV), a major challenge is identifying a cell source for seeding TEHV scaffolds. Native heart valves are durable because valve interstitial cells (VICs) maintain tissue homeostasis by synthesizing and remodeling the extracellular matrix. In this study, the goal is to demonstrate that induced pluripotent stem cells (iPSC)-derived mesenchymal stem cells (iMSCs) can be derived from iPSCs using a feeder-free protocol and then further matured into VICs by encapsulation within 3D hydrogels. The differentiation efficiency was characterized using flow cytometry, immunohistochemistry staining, and trilineage differentiation. Using our feeder-free differentiation protocol, iMSCs were differentiated from iPSCs and had CD90⁺, CD44⁺, CD71⁺, αSMA⁺, and CD45^- expression. iMSCs underwent trilineage differentiation when cultured in induction media for 21 days. iMSCs were encapsulated in poly(ethylene glycol) diacrylate (PEGDA) hydrogels, grafted with adhesion peptide (RGDS), to promote remodeling and further maturation into VIC-like cells. VIC phenotype was assessed by the expression of alpha-smooth muscle actin (αSMA), vimentin, and the collagen production after 28 days. When MSC-derived cells were encapsulated in PEGDA hydrogels that mimic the leaflet modulus, we observed a decrease in αSMA expression and increase in vimentin. In addition, iMSCs synthesized collagen type I after 28 days in 3D hydrogel culture. Thus, the results from this study suggest that iMSCs may be a promising cell source for TEHV.Statement of SignificanceDeveloping a suitable cell source is a critical component for the success and durability of tissue engineered heart valves. The significance of this study is the generation of iPSCs-derived mesenchymal stem cells (iMSCs) that have the capacity to mature into valve interstitial-like cells when introduced into a 3D cell culture designed to mimic the layers of the valve leaflet. iMSCs were generated using a feeder-free protocol, which is one of the major advantage over other methods, as it is more clinically relevant. In addition to generating a potential new cell source for heart valve tissue engineering, this study also highlights the importance of a 3D culture environment to influence cell phenotype and function.

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