Direct Reprogramming of Murine Fibroblasts to Hematopoietic Progenitor Cells

Abstract

SummaryRecent reports have shown that somatic cells, under appropriate culture conditions, could be directly reprogrammed to cardiac, hepatic, or neuronal phenotype by lineage-specific transcription factors. In this study, we demonstrate that both embryonic and adult somatic fibroblasts can be efficiently reprogrammed to clonal multilineage hematopoietic progenitors by the ectopic expression of the transcription factors ERG, GATA2, LMO2, RUNX1c, and SCL. These reprogrammed cells were stably expanded on stromal cells and possessed short-term reconstitution ability in vivo. Loss of p53 function facilitated reprogramming to blood, and p53−/− reprogrammed cells efficiently generated erythroid, megakaryocytic, myeloid, and lymphoid lineages. Genome-wide analyses revealed that generation of hematopoietic progenitors was preceded by the appearance of hemogenic endothelial cells expressing endothelial and hematopoietic genes. Altogether, our findings suggest that direct reprogramming could represent a valid alternative approach to the differentiation of embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) for disease modeling and autologous blood cell therapies.

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

“…Comparative transcriptomics of HSC and progenitor cell populations often provided lists of candidate factors to overexpress. Although many of the factors used in reprogramming studies have previously been implicated in developmental haematopoiesis, their true 'haematopoietic potency' becomes unveiled when they are expressed in a foreign cellular context, such as when reprogramming fibroblasts Batta et al, 2014) or undifferentiated PSCs (Elcheva et al, 2014;Vereide et al, 2014) (see Fig. 5 for details).…”

“…Ultimately, the safest HSCs generated in the dish would likely be genetically unaltered cells, produced by exposure to external factors equivalent to the embryonic cues that drive HSC development. Here, the bottleneck seems to be identifying the combinations of soluble and cell-based factors and (Vereide et al, 2014); (2) (Kyba et al, 2002;Lu et al, 2016); (3) ; (4) (Elcheva et al, 2014); note that GATA2/ SCL combination induces erythro-megakaryocytic differentiation (not shown); (5) (Sandler et al, 2014); (6) (Riddell et al, 2014); (7) ; (8) (Batta et al, 2014); (9) (Cheng et al, 2016); (10) (Pulecio et al, 2014); (11) (Lis et al, 2017); (12) (Sugimura et al, 2017). CLPs, common lymphoid progenitors; CMPs, common myeloid progenitors; MPPs, multipotent progenitors.…”

“…These studies spawned quests for combinations of transcription factors, overexpression of which could generate clinically relevant cell types, including HSCs. Groups chose either ESCs (Kyba et al, 2002;Elcheva et al, 2014), human endothelial cells (Sandler et al, 2014), haematopoietic cells or fibroblasts Batta et al, 2014) as the starting material. Comparative transcriptomics of HSC and progenitor cell populations often provided lists of candidate factors to overexpress.…”

Bioinformatic and Genomic Analyses of Cellular Reprogramming and Direct Lineage Conversion

“…With these datasets, investigators are able to generate candidate genes which may be capable of direct conversion as well as use defined lineage specific networks as a benchmark for proper lineage reprogramming. Many of these rely on a study of the gene expression networks in the target cells to confirm proper lineage conversion including hematopoietic stem and progenitor cells (iHSC, iHPC, [4,73,85]), embryonic sertoli-like cells (ieSCs, [13]), endothelial cells (iECs, [33]), and melanocytes (iMels, [101]). …”

Direct reprogramming of somatic cells: an update

“…Therefore, direct reprogramming should be improved in order to produce proliferating cells such as tissue specific stem cells or progenitor cells more than fully differentiated cells. In fact, some kinds of stem cells as well as progenitor cells were produced by direct reprogramming technology, including neural stem cells or progenitors (Han et al, 2012;Schindeler et al, 2015;Thier et al, 2012), oligodendrocyte precursor cells (Najm et al, 2013), hepatic stem cells , HSCs (Riddell et al, 2014), and hematopoietic multipotent progenitors (Batta et al, 2014;Sandler et al, 2014).…”