In vivo evaluation of putative hematopoietic stem cells derived from human pluripotent stem cells

Efficient derivation and isolation of hematopoietic stem cells (HSCs) from human pluripotent stem cell (hPSC) populations remains a major goal in the field of developmental hematopoiesis. These enticing pluripotent stem cells (comprising both human embryonic stem cells and induced pluripotent stem cells) have been successfully used to generate a wide array of hematopoietic cells in vitro, from primitive hematoendothelial precursors to mature myeloid, erythroid, and lymphoid lineage cells. However, to date, PSC-derived cells have demonstrated only limited potential for long-term multilineage hematopoietic engraftment in vivo - the test by which putative HSCs are defined. Successful generation and characterization of HSCs from hPSCs not only requires an efficient in vitro differentiation system that provides insight into the developmental fate of hPSC-derived cells, but also necessitates an in vivo engraftment model that allows identification of specific mechanisms that hinder or promote hematopoietic engraftment. In this chapter, we will describe a method that utilizes firefly luciferase-expressing hPSCs and bioluminescent imaging to noninvasively track the survival, proliferation, and migration of transplanted hPSC-derived cells. Combined with lineage and functional analyses of engrafted cells, this system is a useful tool to gain insight into the in vivo potential of hematopoietic cells generated from hPSCs.