Human ES/iPS Neural Induction Medium

Dual SMAD inhibition is a well-established method to derive neural progenitor cells from both human ES and iPS cells. This protocol uses two SMAD inhibitors, Noggin and SB431542, to drive the rapid differentiation of ES/iPS cells into a highly enriched population of NPCs. Noggin acts as a BMP inhibitor and SB431542 inhibits the Lefty/Activin/TGFβ pathways by blocking the phosphorylation of ALK4, ALK5, and ALK7 receptors. In an effort to make a more defined and optimized neuronal differentiation protocol, Li and colleagues modified the original protocol to establish a completely small molecule-based differentiation method, which relies on three small molecules to inhibit GSK-3β (CHIR99021), TGFβ (SB431542), and Notch (compound E) signaling pathways, along with human LIF3. This new small molecule-based neural differentiation protocol increased neural differentiation kinetics and allowed the derivation of truly multipotent neural stem cells that respond to regional patterning cues specifying forebrain, midbrain, and hindbrain neural and glial subtypes.