Derivation of megakaryocytes and platelets from human pluripotent stem cells

Megakaryocytes (MKs), rare hematopoietic cells in adult bone marrow, produce platelets that are critical to vascular hemostasis and wound healing. Ex vivo generation of MKs from human induced pluripotent stem cells (hiPSCs) provides a renewable cell source of platelets for treating thrombocytopenic patients and allows a better understanding of MK/platelet biology. The key requirements in this approach include developing a robust and consistent method for the production of functional progeny cells, such as MKs from hiPSCs, and minimizing risk and variation due to the animal-derived products in cell cultures. Here, we describe an efficient system to generate MKs from hiPSCs under a feeder-free and xeno-free condition, in which all the animal-derived products were eliminated. Several crucial reagents were evaluated and replaced with FDA-approved pharmacological reagents, including romiplostim (Nplate®, a thrombopoietin analog), Oprelvekin (recombinant IL-11), and Plasbumin (human albumin). This basic and defined differentiation system provides a platform for our future effort in investigation of regulatory factors and protocol optimization toward generating large numbers of platelets ex vivo.