Article

RUNX1a enhances hematopoietic lineage commitment from human embryonic stem cells and inducible pluripotent stem cells

Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, United States
Blood (Impact Factor: 10.45). 01/2013; 121(15). DOI: 10.1182/blood-2012-08-451641
Source: PubMed

ABSTRACT

Advancements in human pluripotent stem cells (hPSCs) research have potential to revolutionize therapeutic transplantation. It has been demonstrated that transcription factors may play key roles in regulating maintenance, expansion, and differentiation of hPSCs. In addition to its regulatory functions in hematopoiesis and blood-related disorders, the transcription factor RUNX1 is also required for the formation of definitive blood stem cells. In the current study, we demonstrated that expression of endogenous RUNX1a, an isoform of RUNX1, parallels with lineage commitment and hematopoietic emergence from hPSCs, including both human embryonic stem cells and inducible pluripotent stem cells. In a defined hematopoietic differentiation system, ectopic expression of RUNX1a facilitates emergence of hematopoietic progenitor cells (HPCs) and positively regulates expression of mesoderm and hematopoietic differentiation related factors, including Brachyury, KDR, SCL, GATA2, and PU.1. HPCs derived from RUNX1a-hPSCs show enhanced expansion ability and the ex vivo expanded cells are capable of differentiating into multiple lineages. Expression of RUNX1a in embryoid bodies (EBs) promotes definitive hematopoiesis that generates erythrocytes with β-globin production. Moreover, HPCs generated from RUNX1a-EBs possess at least 9 weeks repopulation ability and show multi-lineage hematopoietic reconstitution in vivo. Together, our results suggest that RUNX1a facilitates the process of producing therapeutic HPCs from hPSCs.

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    • "We previously demonstrated that CD34 þ CD31 þ CD144 þ population from hPSCs contains hemato-endothelial progenitors (HEPs) that give rise to hematopoietic cells and endothelial cells (Bai et al., 2010; Bai et al., 2013; Xie et al., 2015). The key transcription factors required for definitive hematopoietic cell generation from hemogenic ECs, including SCL and RUNX1 (Lacaud et al., 2002; Patterson et al., 2005; Nottingham et al., 2007; Dzierzak and Speck, 2008; Chen et al., 2009; Lam et al., 2010; Ren and Gomez, 2010; Van et al., 2012; Ran et al., 2013; Zhen et al., 2013), are expressed in CD34 þ CD31 þ CD144 þ cells (Bai et al., 2013). In the present study, we established a stepwise differentiation system to interrogate hematopoietic cells from the endothelial monolayer derived from HEPs. "
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    ABSTRACT: Generation of fully functional hematopoietic multipotent progenitor (MPP) cells from human pluripotent stem cells (hPSCs) has a great therapeutic potential to provide an unlimited cell source for treatment of hematological disorders. We previously demonstrated that CD34(+) CD31(+) CD144(+) population derived from hPSCs contain hemato-endothelial progenitors (HEPs) that give rise to hematopoietic and endothelial cells. Here, we report a differentiation system to generate definitive hematopoietic MPP cells from HEPs via endothelial monolayer. In the presence of angiogenic factors, HEPs formed an endothelial monolayer, from which hematopoietic clusters emerged through the process of endothelial-to-hematopoietic transition (EHT). EHT was significantly enhanced by hematopoietic growth factors. The definitive MPP cells generated from endothelial monolayer were capable of forming multilineage hematopoietic colonies, giving rise to T lymphoid cells, and differentiating into enucleated erythrocytes. Emergence of hematopoietic cells from endothelial monolayer occurred transiently. Hematopoietic potential was lost during prolonged culture of HEPs in endothelial growth conditions. Our study demonstrated that CD34(+) CD31(+) CD144(+) HEPs gave rise to hematopoietic MPP cells via hemogenic endothelial cells that exist transiently. The established differentiation system provides a platform for future investigation of regulatory factors involved in de novo generation of hematopoietic MPP cells and their applications in transplantation. This article is protected by copyright. All rights reserved.
    Full-text · Article · Sep 2015 · Journal of Cellular Physiology
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    • "In this line, inducing a definitive hematopoietic program during the in vitro differentiation process of PSCs may resemble the prerequisite to generate HSCs with long-term engraftment potential. Probably, this switch from the primitive to definitive hematopoiesis represents the bottleneck that is hindering the efficient long-term engraftment potential of PSC-derived hematopoietic stem/progenitor cells (HSPCs) so far (Szabo et al, 2010; Ran et al, 2013) (see also Fig 2). Whereas the distinct waves of hematopoiesis are temporally and spatially separated during embryonic development in vivo, culture systems do not allow this clear separation, so that both developmental processes simultaneously coexist in vitro. "
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    ABSTRACT: Pluripotent stem cells (PSCs) such as embryonic stem cells or induced pluripotent stem cells represent a promising cell type to gain novel insights into human biology. Understanding the differentiation process of PSCs in vitro may allow for the identification of cell extrinsic/intrinsic factors, driving the specification process toward all cell types of the three germ layers, which may be similar to the human in vivo scenario. This would not only lay the ground for an improved understanding of human embryonic development but would also contribute toward the generation of novel cell types used in cell replacement therapies. In this line, especially the developmental process of mesodermal cells toward the hematopoietic lineage is of great interest. Therefore, this review highlights recent progress in the field of hematopoietic specification of pluripotent stem cell sources. In addition, we would like to shed light on emerging factors controlling primitive and definitive hematopoietic development and to highlight recent approaches to improve the differentiation potential of PSC sources toward hematopoietic stem/progenitor cells. While the generation of fully defined hematopoietic stem cells from PSCs remains challenging in vitro, we here underline the instructive role of cell extrinsic factors such as cytokines for the generation of PSC-derived mature hematopoietic cells. Thus, we have comprehensively examined the role of cytokines for the derivation of mature hematopoietic cell types such as macrophages, granulocytes, megakaryocytes, erythrocytes, dendritic cells, and cells of the B- and T-cell lineage. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.
    Full-text · Article · Jul 2015 · EMBO Molecular Medicine
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    • "Transcription factors that specify human HSC identity and/or expand human HSCs are critical for differentiating iPSCs into HSCs with long-term hematopoiesis potential, and the search for new factors deserves special focus. Recently, Dong-Er Zhang and colleagues found that RUNX1a facilitates the differentiation of human iPSCs into HSCs that can engraft immunodeficient mice [119]. Another report from Pereira et al. [120] shows that a combination of 4 factors––Gata2, Gfi1b, c-Fos and Ets6––leads to conversion of mouse fibroblasts to hematopoietic progenitor cells. "
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    ABSTRACT: Breakthroughs in cell fate conversion have made it possible to generate large quantities of patient-specific cells for regenerative medicine. Due to multiple advantages of peripheral blood cells over fibroblasts from skin biopsy, the use of blood mononuclear cells (MNCs) instead of skin fibroblasts will expedite reprogramming research and broaden the application of reprogramming technology. This review discusses current progress and challenges of generating induced pluripotent stem cells (iPSCs) from peripheral blood MNCs and of in vitro and in vivo conversion of blood cells into cells of therapeutic value, such as mesenchymal stem cells, neural cells and hepatocytes. An optimized design of lentiviral vectors is necessary to achieve high reprogramming efficiency of peripheral blood cells. More recently, non-integrating vectors such as Sendai virus and episomal vectors have been successfully employed in generating integration-free iPSCs and somatic stem cells.
    Full-text · Article · Sep 2013
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