Wnt signaling controls the specification of definitive and primitive hematopoiesis from human pluripotent stem cells

Abstract

Efforts to derive hematopoietic stem cells (HSCs) from human pluripotent stem cells (hPSCs) are complicated by the fact that embryonic hematopoiesis consists of two programs, primitive and definitive, that differ in developmental potential. As only definitive hematopoiesis generates HSCs, understanding how this program develops is essential for being able to produce this cell population in vitro. Here we show that both hematopoietic programs transition through hemogenic endothelial intermediates and develop from KDR+CD34−CD144− progenitors that are distinguished by CD235a expression. Generation of primitive progenitors (KDR+CD235a+) depends on stage-specific Activin-nodal signaling and inhibition of the Wnt-β-catenin pathway, whereas specification of definitive progenitors (KDR+CD235a−) requires Wnt-β-catenin signaling during this same time frame. Together, these findings establish simple selective differentiation strategies for the generation of primitive or definitive hematopoietic progenitors via Wnt-β-catenin manipulation, and in doing so provide access to enriched populations for future studies on hPSC-derived hematopoietic development.

Human haematopoietic stem cell development: from the embryo to the dish

“…As well as the surface markers KDR and PDGFRα, blast colony-forming cells (BL-CFCs) also express the apelin receptor (Vodyanik et al, 2010;Choi et al, 2012;Yu et al, 2012), and CD235a (glycophorin A) (Sturgeon et al, 2014). As in the mouse (Huber et al, 2004), human blast colonies give rise to haematopoietic, endothelial and smooth muscle lineages (Yu et al, 2012).…”

“…Following an initial period of BMP4-based mesoderm induction, brief inhibition of activin (Kennedy et al, 2012), or provision of a WNT agonist (Gertow et al, 2013) were sufficient to inhibit the erythroid-biased primitive programme. Importantly, activin inhibition (Kennedy et al, 2012), WNT stimulation (Sturgeon et al, 2014) or a combination of the two (Ng et al, 2016) from days 2-4 of in vitro differentiation also resulted in a bias towards definitive haematopoietic lineages, as defined by the capacity to generate T lymphocytes (Kennedy et al, 2012;Sturgeon et al, 2014).…”

Vascular niche promotes hematopoietic multipotent progenitor formation from pluripotent stem cells

“…Previous work from several groups shows that hematoendothelial precursors specified toward hematopoietic fate by coculture with growth factors alone (23)(24)(25) or with stromal cell support (2,26) give rise to phenotypic but primitive hematopoietic progenitors that lack robust, long-term multilineage engraftment potential.…”

On human development: lessons from stem cell systems

“…He addressed the difficulties in producing true, clinically relevant HSCs from human ESCs and described his strategy to achieve this goal (Kennedy et al, 2012;Sturgeon et al, 2014). Keller underscored that the haematopoietic lineage is segregated from the mesoderm at very early stages of embryogenesis, and that this must be taken into account for in vitro ESC differentiation protocols.…”