Methods to produce induced pluripotent stem cell-derived mesenchymal stem cells: Mesenchymal stem cells from induced pluripotent stem cells

Abstract

Mesenchymal stem cells (MSCs) have received significant attention in recent years due to their large potential for cell therapy. Indeed, they secrete a wide variety of immunomodulatory factors of interest for the treatment of immune-related disorders and inflammatory diseases. MSCs can be extracted from multiple tissues of the human body. However, several factors may restrict their use for clinical applications: the requirement of invasive procedures for their isolation, their limited numbers, and their heterogeneity according to the tissue of origin or donor. In addition, MSCs often present early signs of replicative senescence limiting their expansion in vitro, and their therapeutic capacity in vivo. Due to the clinical potential of MSCs, a considerable number of methods to differentiate induced pluripotent stem cells (iPSCs) into MSCs have emerged. iPSCs represent a new reliable, unlimited source to generate MSCs (MSCs derived from iPSC, iMSCs) from homogeneous and well-characterized cell lines, which would relieve many of the above mentioned technical and biological limitations. Additionally, the use of iPSCs prevents some of the ethical concerns surrounding the use of human embryonic stem cells. In this review, we analyze the main current protocols used to differentiate human iPSCs into MSCs, which we classify into five different categories: MSC Switch, Embryoid Body Formation, Specific Differentiation, Pathway Inhibitor, and Platelet Lysate. We also evaluate common and method-specific culture components and provide a list of positive and negative markers for MSC characterization. Further guidance on material requirements to produce iMSCs with these methods and on the phenotypic features of the iMSCs obtained is added. The information may help researchers identify protocol options to design and/or refine standardized procedures for large-scale production of iMSCs fitting clinical demands.

Keywords: Mesenchymal stem cells; Induced pluripotent stem cells; Mesenchymal stem cells derived from induced pluripotent stem cells; Differentiation methods; Culture components; Mesenchymal stem cell markers

Core Tip: Heterogeneity of mesenchymal stem cell (MSC) quality might have hampered the robust success of stem cell clinical trials (CTs). The production of MSCs from a single homogeneous source (i.e. induced pluripotent stem cells, iPSCs) could elevate stem cell therapeutics standardization to unprecedented levels. However, a unique optimized procedure for large-scale production of MSCs, of homogenous quality, from iPSCs (iMSCs) is missing. Main methods, culture components, and common MSC markers to produce iMSCs are provided here as reference resources for the establishment of harmonized Good Manufacturing Procedures towards obtaining clinical-grade iMSCs with improved CT performance.