Differentiation was carried out as previously described [48 (link)] with slight modifications. Briefly, iPSCs were passaged sparsely to 6-well Matrigel-coated plates and cultured for 8–10 days in mTeSR1 with daily medium changes until the colonies were approximately 1 cm in diameter. Next, embryoid bodies (EBs) were formed by gently lifting colonies using a cell lifter. Colonies were gently transferred to a 15 ml conical tube using a 10 ml serological pipette. Colonies were allowed to gravity settle for approximately 5 minutes and supernatant was aspirated. Cell were gently resuspended in mTeSR1 supplemented with 10 μM ROCK inhibitor (Y-27632) and transferred to Ultra-Low Attachment Surface 6-well plates (Corning) containing 4 mL medium per well. EBs were allowed to form for 4 days with a partial (2/3) medium change after 48 hours. On day 4, EBs were collected, washed, resuspended in X-VIVO15 supplemented with GlutaMAX™ (Gibco) and 2-mercaptoethanol (Gibco), and transferred to adherent, cell culture treated plates.