title: Vascular niche promotes hematopoietic multipotent progenitor formation from pluripotent stem cells.
abstract: Pluripotent stem cells (PSCs) represent an alternative hematopoietic stem cell (HSC) source for treating hematopoietic disease. The limited engraftment of human PSC-derived (hPSC-derived) multipotent progenitor cells (MPP) has hampered the clinical application of these cells and suggests that MPP require additional cues for definitive hematopoiesis. We hypothesized that the presence of a vascular niche that produces Notch ligands jagged-1 (JAG1) and delta-like ligand-4 (DLL4) drives definitive hematopoiesis. We differentiated hes2 human embryonic stem cells (hESC) and Macaca nemestrina-induced PSC (iPSC) line-7 with cytokines in the presence or absence of endothelial cells (ECs) that express JAG1 and DLL4. Cells cocultured with ECs generated substantially more CD34+CD45+ hematopoietic progenitors compared with cells cocultured without ECs or with ECs lacking JAG1 or DLL4. EC-induced cells exhibited Notch activation and expressed HSC-specific Notch targets RUNX1 and GATA2. EC-induced PSC-MPP engrafted at a markedly higher level in NOD/SCID/IL-2 receptor γ chain-null (NSG) mice compared with cytokine-induced cells, and low-dose chemotherapy-based selection further increased engraftment. Long-term engraftment and the myeloid-to-lymphoid ratio achieved with vascular niche induction were similar to levels achieved for cord blood-derived MPP and up to 20-fold higher than those achieved with hPSC-derived MPP engraftment. Our findings indicate that endothelial Notch ligands promote PSC-definitive hematopoiesis and production of long-term engrafting CD34+ cells, suggesting these ligands are critical for HSC emergence.
authors: Jennifer L
authors: JL
authors: Gori
authors: Jason M
authors: JM
authors: Butler
authors: Yan-Yi
authors: YY
authors: Chan
authors: Devikha
authors: D
authors: Chandrasekaran
authors: Michael G
authors: MG
authors: Poulos
authors: Michael
authors: M
authors: Ginsberg
authors: Daniel J
authors: DJ
authors: Nolan
authors: Olivier
authors: O
authors: Elemento
authors: Brent L
authors: BL
authors: Wood
authors: Jennifer E
authors: JE
authors: Adair
authors: Shahin
authors: S
authors: Rafii
authors: Hans-Peter
authors: HP
authors: Kiem
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology*; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000502:physiology*; D008254:Macaca nemestrina; D008297:Male; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D039902:Multipotent Stem Cells / Q000502:physiology*; D055153:Stem Cell Niche