Direct conversion of human fibroblasts to multilineage blood progenitors
Ontology highlight
ABSTRACT: Similar to embryo-derived stem cells, application of human induced pluripotent stem cells (iPSCs) is limited by our understanding of lineage specification. Here, we demonstrate the ability to generate progenitors and mature cells of the hematopoietic fate directly from human dermal fibroblasts without establishing pluripotency. POU domain activation of hematopoietic transcription factors by ectopic expression of Oct-4, together with specific cytokine treatment, allowed generation of cells expressing the pan-leukocyte marker CD45. These unique fibroblast-derived cells gave rise to granulocytic, monocytic, megakaryocytic, and erythroid lineages, and demonstrated in vivo engraftment capacity. Distinct from PSC-derived hematopoietic cells, adult and not embryonic hematopoietic programs are activated, consistent with bypassing pluripotent state to generate blood fate. These findings suggest an alternative approach to cellular reprogramming for autologous cell-replacement therapies that avoids complications associated with the use of human PSCs. Molecular analysis was done on purified untransduced Fibs, Oct-4 transduced Fibs at day 4, CD45+ve Fibs at day 21 and hematopoietic cytokine treated CD45+ve Fibs at day 37. The day 4 Oct-4 transduced Fibs were isolated by puromycin selection overnight (Oct-4 vector contains puromycin resistance cassette), purity of sample was validated by staining for Oct-4 followed by Oct-4 expression analysis using flow cytometry; samples used for molecular analysis exhibited 99% Oct-4 levels. The day 21 and day 37 CD45+veFibsOct-4 were isolated based on their CD45 expression. D21 and D37 cells were stained with CD45-APC antibody (BD Biosciences) and sorted using FACSAria II (Becton- Dickinson); samples used for molecular analysis exhibited 99% CD45 levels. Analysis was performed on two biological replicates per sample.
Project description:Analysis of CD41 single positive, VE-cadherin single positive, double positive, and double negatvie populations among 7AAD-CD45- cells from day 6 EBs
Project description:Interferon-alpha promotes engraftment of mid-gestation hematopoietic stem cells by promoting competitiveness and restore the hematopoietic defect of Arid3a knockout embryos We used microarray to response of AGM HSCs (VE+CD45+) to IFNa (0.5ng/ml) treatment for 4 hours
Project description:Similar to embryo-derived stem cells, application of human induced pluripotent stem cells (iPSCs) is limited by our understanding of lineage specification. Here, we demonstrate the ability to generate progenitors and mature cells of the hematopoietic fate directly from human dermal fibroblasts without establishing pluripotency. POU domain activation of hematopoietic transcription factors by ectopic expression of Oct-4, together with specific cytokine treatment, allowed generation of cells expressing the pan-leukocyte marker CD45. These unique fibroblast-derived cells gave rise to granulocytic, monocytic, megakaryocytic, and erythroid lineages, and demonstrated in vivo engraftment capacity. Distinct from PSC-derived hematopoietic cells, adult and not embryonic hematopoietic programs are activated, consistent with bypassing pluripotent state to generate blood fate. These findings suggest an alternative approach to cellular reprogramming for autologous cell-replacement therapies that avoids complications associated with the use of human PSCs.
Project description:Etv2 transgene was expressed from ROSA26 locus by removing floxed STOP cassette by Tie-2 Cre transgene. VE-Cad+/CD45= or VE-Cad+/CD45+ cells were sorted from control or tie-2-Etv2 E11.5 embryos (YS;yolk sac and Emb;embryo proper)and compared for gene expression in duplicate.
Project description:In vitro generation of mature neutrophils from human induced pluripotent stem cells (iPSCs) requires hematopoietic progenitor development followed by myeloid differentiation. The purpose of our studies was to extensively characterize this process, focusing on the critical window of development between hemogenic endothelium, hematopoietic stem/progenitor cells (HSPCs), and myeloid commitment, to identify associated regulators and markers that might enable the stem cell field to improve the efficiency and efficacy of iPSC hematopoiesis. We utilized a 4-stage differentiation protocol involving: embryoid body (EB) formation (Stage-1); EB culture with hematopoietic cytokines (Stage-2); HSPC expansion (Stage-3); and neutrophil maturation (Stage-4). CD34+CD45- putative hemogenic endothelial cells were observed in Stage-3 cultures, and expressed VEGFR-2/Flk-1/KDR and VE-cadherin endothelial markers, GATA-2, AML1/RUNX1, and SCL/TAL1 transcription factors, and endothelial/HSPC-associated microRNAs miR-24, miR-125a-3p, miR-126/126*, and miR-155. Upon further culture, CD34+CD45- cells generated CD34+CD45+ HSPCs that produced hematopoietic CFUs. Mid-Stage-3 CD34+CD45+ HSPCs exhibited increased expression of GATA-2, AML1/RUNX1, SCL/TAL1, C/EBPα, and PU.1 transcription factors, but exhibited decreased expression of HSPC-associated microRNAs, and failed to engraft in immune-deficient mice. Mid-stage-3 CD34-CD45+ cells maintained PU.1 expression and exhibited increased expression of hematopoiesis-associated miR-142-3p/5p and a trend towards increased miR-223 expression, indicating myeloid commitment. By late Stage-4, increased CD15, CD16b, and C/EBPε expression were observed, with 25-65% of cells exhibiting morphology and functions of mature neutrophils. These studies demonstrate that hematopoiesis and neutrophil differentiation from human iPSCs recapitulates many features of embryonic hematopoiesis and neutrophil production in marrow, but reveals unexpected molecular signatures that may serve as a guide for enhancing iPSC hematopoiesis. miRNA expression profiles were analyzed in iNC-01-3 and iNC-01-4 induced pluripotent stem cell lines at day 0 (undifferentiated iPSCs), day 18 of differentiation (embryoid bodies), and in 3 FACS-sorted cell populations at day 22 of differentiation (CD34+CD45- cells, CD34+CD45+ cells, and CD34-CD45+ cells). Comparative CT analysis was normalized to U6 snRNA and RNU48 control RNAs relative to expression in undifferentiated iPSCs. Data includes 2 files for each sample, one for the card A array and one for the card B array. This includes a total of 32 data files consisting of: 5 replicates for undifferentiated iPSCs (10 files), 2 replicates for EB (4 files), 3 replicates for CD34+CD45- (6 files), 3 replicates for CD34+CD45+ (6 files), and 3 replicates for CD34-CD45+ (6 files).
Project description:Human embryonic stem cells (hESCs) are a powerful tool for modeling regenerative therapy. To search for the genes that promote hematopoietic development from human pluripotent stem cell, we overexpressed a list of hematopoietic regulator genes in human pluripotent stem cell-derived CD34+CD43- endothelial cells (ECs) enriched in hemogenic endothelium. Among genes tested, only SOX17, a gene encoding a transcription factor of the SOX family, promoted cell growth and supported expansion of CD34+CD43+CD45-/low cells expressing a hemogenic endothelial maker VE-cadherin. SOX17 was highly expressed in CD34+CD43- ECs but at a low level in CD34+CD43+CD45- pre-hematopoietic progenitor cells (pre-HPCs) and CD34+CD43+CD45+ HPCs. SOX17-overexpressing cells formed sphere-like colonies and generated few hematopoietic progenies. However, they retained hemogenic potential and gave rise to hematopoietic progenies upon inactivation of SOX17. Global gene expression analyses revealed that the CD34+CD43+CD45-/low cells expanded upon overexpression of SOX17 are hemogenic endothelium-like cells developmentally placed between ECs and pre-HPCs. Of interest, SOX17 also reprogrammed both pre-HPCs and HPCs into hemogenic endothelium-like cells. Genome-wide mapping of SOX17 revealed that SOX17 directly activates transcription of key regulator genes for vasculogenesis, hematopoiesis, and erythrocyte differentiation. Depletion of SOX17 in CD34+CD43- ECs severely compromised their hemogenic activity. These findings suggest that SOX17 plays a critical role in priming hemogenic potential in ECs, thereby regulates hematopoietic development from hESCs. This SuperSeries is composed of the SubSeries listed below.
Project description:During hematopoietic differentiation of hESCs, HOXA9 expression parallels hematopoietic development but is restricted to the hemogenic precursors (HEP, CD31+CD34+CD45-), and diminishes as HEPs differentiate into blood cells (CD45+). Enforced expression of Hoxa9 in hESCs robustly promoted differentiation into primitive (CD34+CD45+) and total (CD45+) blood cells with higher clonogenic (CFU) potential. To identify patterns of gene expression that could explain at the molecular level the developmental impact of HOXA9 in hematopoietic commitment of hESCs, we performed gene expression profile in FACS-purified EV- and HOXA9-HEPs. 10^5 HoxA9 over expressing and EV control HEPs purified by FACS from H9 and AND1 hEBs at day 15 of hematopoietic differentiation were used for gene expression analysis using Whole Human Genome Oligo Microarray chips (Agilent Technologies).
Project description:MLL-AF4 is a hallmark genomic aberration which arises prenatally in high-risk infant acute lymphoblastic leukemia (ALL). In human embryonic stem cells (hESCs), MLL-AF4 skewed hemato-endothelial specification but was not sufficient for transformation. Additional cooperating genetic insults seem required for MLL-AF4-mediated leukemogenesis. FLT3 is highly expressed in MLL-AF4+ ALL through activating mutations (FLT3-TKD or FLT3-ITD) or increased transcriptional expression, being therefore considered a potential cooperating event in MLL-AF4+ ALL. Here, we explored the developmental impact of FLT3 activation on its own or in cooperation with MLL-AF4 in the hematopoietic fate of hESCs. FLT3 activation did not impact specification of CD45-CD31+ hemogenic precursors but significantly enhanced the formation of CD45+CD34+ and CD45+ blood cells and blood progenitors with clonogenic potential. Importantly, FLT3 activation through FLT3 mutations or FLT3-WT overexpression completely abrogated hematopoietic differentiation from MLL-AF4-expressing hESCs, indicating that FLT3 activation cooperates with MLL-AF4 to inhibit human embryonic hematopoiesis. Cell cycle/apoptosis analyses suggest that FLT3 activation directly impacts hESC specification rather than selective proliferation/survival of hESC-emerging hematopoietic derivatives. Transcriptional profiling supported the limited impact of FLT3 activation on hESC specification towards CD45-hemogenic precursors and the enhanced hematopoiesis upon FLT3 activation, and inhibited hematopoiesis upon MLL-AF4 expression in FLT3-activated hESCs which was associated to large transcriptional changes and regulation of master early hematopoietic genes. Also, although FLT3 activation and MLL-AF4 cooperate to inhibit embryonic hematopoiesis the underlying molecular/genetic mechanisms differ depending on how FLT3 activation is achieved. Finally, FLT3 activation did not cooperate with MLL-AF4 to immortalize/transform hESC-derived hematopoietic cells. 18 samples were analyzed. CD45- hemogenic precursors EV, 2 biological rep CD45- hemogenic precursors FLT3-TKD, 2 biological rep CD45- hemogenic precursors FLT3-WT, 2 biological rep CD45- hemogenic precursors FLT3-TKD/MLLAF4, 2 biological rep CD45- hemogenic precursors FLT3-WT/MLLAF4, 2 biological rep CD45+ blood cells EV, 1 biological rep CD45+ blood cells FLT3-TKD, 2 biological rep CD45+ blood cells FLT3-WT, 2 biological rep CD45+ blood cells FLT3-TKD/MLLAF4, 2 biological rep CD45+ blood cells FLT3-WT/MLLAF4, 1 biological rep
Project description:Analysis of CD41 single positive, VE-cadherin single positive, double positive, and double negatvie populations among 7AAD-CD45- cells from day 6 EBs Doxycline-inducible ICN1 ES cells were differentiated into EBs and ICN1 was induced from day 3-5. Non-induced or induced day 6 EBs were dissociated and subjected to FACS sorting and RNA extraction.
Project description:We performed lineage tracing experiments using VE-Cadherin-Cre;LoxP-tdTomato mice. In these mice, endothelial cells (ECs) and their progeny are permanently marked by tdTomato fluorescence. We found that a substantial subset of stromal cells is derived from ECs, as indicated by their tdTomato expression. These findings support the notion that endothelial to mesenchymal transition (EndoMT) contributes to hematopoietic bone marrow niche formation in mice. Here we sought to determine the transcriptomic differences between endothelial-derived (tdTomato-positive) and non-endothelial-derived (tdTomato-negative) bone marrow stromal cells (BMSCs) and osteo/chondrolineage progenitor cells (OLCs). Murine niche populations were obtained from collagenased bone fraction of VE-Cadherin-Cre;LoxP-tdTomato mice at 3 weeks (n=2) or 11 weeks (n=2) of age. BMSCs (CD45-TER119-CD31-CD144-SCA-1+ CD51+ cells) and OLCs (CD45-TER119-CD31-CD144-Sca1-CD51+ cells) were FACS-purified and sequenced.