Mesenchymal stromal cells (MSCs) are mesoderm-derived adult pluripotent stem cells1. MSCs are present in almost all connective tissues2. Since MSCs were first discovered in the 1970s and successfully isolated from bone marrow in 1987 by Friedenstein et al.3,4,5, a variety of human somatic (including fetal and adult) tissues have been used for isolating MSCs such as bone, cartilage, tendon, muscle, adipose tissue, and hematopoietic-supporting stroma1,2,6,7. MSCs demonstrate high proliferative capabilities and plasticity to differentiate into many somatic cell lineages and could migrate to injured and inflamed tissues2,8,9. These properties make MSCs a potential candidate for regenerative medicine10. However, somatic tissue-derived MSCs (st-MSCs) are restricted by limited donation, limited cell proliferative capacity, quality variations, and biosafety concern for possible transmission of pathogens, if any, from the donors11,12.
Human induced pluripotent stem cells (hiPSCs) are derived from adult cells reprogramming with transcription factors (Oct4, Sox2, Klf4, and c-Myc), which have similar functions as embryonic stem cells13,14. They can self-renew and possess the potential of differentiating into any type of somatic cells, including MSCs. Compared with st-MSCs, iPSC-MSCs has the advantage of unlimited supply, lower cost, higher purity, convenience in quality control, easy for scale production and gene modification15,16,17.
Due to these advantages of iPSC-MSCs, a variety of methods driving MSC from iPSC have been reported. These differentiation methods have been centered around two culture methodologies: (1) the formation of embryoid bodies (EBs) and (2) the use of monolayer cultures11,18,19,20. Herein, a representative approach for each of the two methodologies was characterized. Furthermore, comparisons between two representative approaches based on time, cost, proliferative ability, expression of MSC biomarkers, and differentiation capability in vitro were also accessed.