Skeletal muscle generated from induced pluripotent stem cells - induction and application

Figure 1 Step-wise induction of skeletal muscle from human embryonic stem/induced pluripotent stem cells and their application. In many protocols, pluripotent stem cells are first induced to differentiate into paraxial mesoderm using a GSK3 inhibitor (activation of Wnt signal) and a BMP4 inhibitor, and they then differentiate into premyogenic progenitors in serum-free DMEM/F12-ITS (or KSR) medium supplemented with growth factors such as FGF-2, IGF-1, or HGF. After differentiation into muscle progenitors, the cells are induced to precursor cells (myoblasts) and then differentiate into multinucleated myotubes (in vitro) and myofibers (in vivo). The transition from embryonic to fetal myoblasts and finally into adult myoblasts is thought to occur sequentially in a dish, but the mechanisms and modes are largely unknown. FGF: Fibroblast growth factor; IGF: Insulin-like growth factor; HGF: Hepatocyte growth factor.