scholarly journals Murine AGM single-cell profiling identifies a continuum of hemogenic endothelium differentiation marked by ACE

Blood ◽  
2021 ◽  
Author(s):  
Muhammad Zaki Fadlullah ◽  
Wen Hao Neo ◽  
Michael Lie-a-ling ◽  
Roshana Thambyrajah ◽  
Rahima Patel ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Single Cell ◽  
Great Promise ◽  
Hemogenic Endothelium ◽  
Hematopoietic Stem ◽  
Blood Transplantation ◽  
Angiotensin I Converting Enzyme ◽  
Single Cell Profiling

In vitro generation and expansion of hematopoietic stem cells (HSCs) holds great promise for the treatment of any ailment that relies on bone marrow or blood transplantation. To achieve this, it is essential to resolve the molecular and cellular pathways that govern HSC formation in the embryo. HSCs first emerge in the aorta-gonad-mesonephros region (AGM) where a rare subset of endothelial cells, hemogenic endothelium (HE), undergoes an endothelial-to-hematopoietic transition (EHT). Here, we present full-length single-cell-RNA-sequencing of the EHT process with a focus on HE and dorsal aorta niche cells. By using Runx1b and Gfi1/1b transgenic reporter mouse models to isolate HE, we uncovered that the pre-HE to HE continuum is specifically marked by Angiotensin-I converting enzyme (ACE) expression. We established that HE cells begin to enter the cell cycle near the time of EHT initiation when their morphology still resembles endothelial cells. We further demonstrated that RUNX1 AGM niche cells consist of vascular smooth muscle cells and PDGFRa+ mesenchymal cells and can functionally support hematopoiesis. Overall, our study provides new insights into HE differentiation towards HSC and the role of AGM RUNX1+ niche cells in this process. Our expansive scRNA-seq datasets represents a powerful resource to investigate these processes further.

In Vitro Hematopoietic and Endothelial Cell Development From Cells Expressing TEK Receptor in Murine Aorta-Gonad-Mesonephros Region

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1549-1556 ◽  
Author(s):  
Isao Hamaguchi ◽  
Xu-Ling Huang ◽  
Nobuyuki Takakura ◽  
Jun-ichi Tada ◽  
Yuji Yamaguchi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Single Cell ◽  
Hematopoietic Cells ◽  
Hematopoietic Stem ◽  
Coculture System ◽  
Platelet Endothelial Cell Adhesion ◽  
Stromal Cell Line ◽  
Macrophage Colony

Recent studies have shown that long-term repopulating hematopoietic stem cells (HSCs) first appear in the aorta-gonad-mesonephros (AGM) region. Our immunohistochemistry study showed that TEK+cells existed in the AGM region. Approximately 5% of AGM cells were TEK+, and most of these were CD34+ and c-Kit+. We then established a coculture system of AGM cells using a stromal cell line, OP9, which is deficient in macrophage colony-stimulating factor (M-CSF). With this system, we showed that AGM cells at 10.5 days postcoitum (dpc) differentiated and proliferated into both hematopoietic and endothelial cells. Proliferating hematopoietic cells contained a significant number of colony-forming cells in culture (CFU-C) and in spleen (CFU-S). Among primary AGM cells at 10.5 dpc, sorted TEK+ AGM cells generated hematopoietic cells and platelet endothelial cell adhesion molecule (PECAM)-1+ endothelial cells on the OP9 stromal layer, while TEK− cells did not. When a ligand for TEK, angiopoietin-1, was added to the single-cell culture of AGM, endothelial cell growth was detected in the wells where hematopoietic colonies grew. Although the incidence was still low (1/135), we showed that single TEK+ cells generated hematopoietic cells and endothelial cells simultaneously, using a single-cell deposition system. This in vitro coculture system shows that the TEK+ fraction of primary AGM cells is a candidate for hemangioblasts, which can differentiate into both hematopoietic cells and endothelial cells.

scholarly journals The hemogenic endothelium: a critical source for the generation of PSC-derived hematopoietic stem and progenitor cells

2021 ◽  
Author(s):  
Lucas Lange ◽  
Michael Morgan ◽  
Axel Schambach
Keyword(s):  
Stem Cells ◽  
De Novo ◽  
Cell Types ◽  
Hemogenic Endothelium ◽  
Hematopoietic Stem ◽  
Autologous Cell ◽  
Stem And Progenitor Cells ◽  
Bona Fide

AbstractIn vitro generation of hematopoietic cells and especially hematopoietic stem cells (HSCs) from human pluripotent stem cells (PSCs) are subject to intensive research in recent decades, as these cells hold great potential for regenerative medicine and autologous cell replacement therapies. Despite many attempts, in vitro, de novo generation of bona fide HSCs remains challenging, and we are still far away from their clinical use, due to insufficient functionality and quantity of the produced HSCs. The challenges of generating PSC-derived HSCs are already apparent in early stages of hemato-endothelial specification with the limitation of recapitulating complex, dynamic processes of embryonic hematopoietic ontogeny in vitro. Further, these current shortcomings imply the incompleteness of our understanding of human ontogenetic processes from embryonic mesoderm over an intermediate, specialized hemogenic endothelium (HE) to their immediate progeny, the HSCs. In this review, we examine the recent investigations of hemato-endothelial ontogeny and recently reported progress for the conversion of PSCs and other promising somatic cell types towards HSCs with the focus on the crucial and inevitable role of the HE to achieve the long-standing goal—to generate therapeutically applicable PSC-derived HSCs in vitro.

scholarly journals Ectopic HOXB4 Expression Expands the Pool of Hemogenic Endothelium-Initiating Progenitor Cells during Pluripotent Stem Cell Differentiation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3496-3496
Author(s):  
Nadine Teichweyde ◽  
Lara Kasperidus ◽  
Peter A Horn ◽  
Hannes Klump
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Pluripotent Stem Cell ◽  
Stem Cell Differentiation ◽  
Great Promise ◽  
Hemogenic Endothelium ◽  
Hematopoietic Development

Abstract Generation of hematopoietic stem cells (HSCs) from pluripotent stem cells, in vitro, holds great promise for future somatic gene and cell therapy. So far, HSCs capable of long-term multilineage reconstitution in mice have only been obtained when the homeodomain transcription factor HOXB4 was ectopically expressed during pluripotent stem cell differentiation (Kyba et al. Cell 109(1): 29-37, 2002; Pilat et al. Proc Natl Acad Sci USA 102(34): 12101-12106, 2005; Lesinski et al. Stem Cells Transl Med 1(8): 581-591, 2012). However, the primary "target" cell of HOXB4 during hematopoietic development, in vitro, is not yet known. Its identification is a prerequisite for unambiguously identifying the molecular circuits driving HSC development, at least in vitro. To pin down this cell, we retrovirally expressed HOXB4 or a Tamoxifen-inducible HOXB4-ERT2 fusion protein in different reporter and knock-out mouse embryonic stem cell (ESC) lines. For these experiments, ESCs were differentiated for 6 days as embryoid bodies (EBs), dissociated and subsequently cocultured on OP9 stroma cells in medium supplemented with 100 ng/ml mSCF, 40 ng/ml mTPO, 100 ng/ml hFlt3L and 40 ng/ml hVEGF (STFV) for further 3 days. Use of a Runx1(-/-) ESC-line containing a doxycycline-inducible Runx1 coding sequence (“iRunx1”; kindly provided by G. Lacaud, Manchester) uncovered that HOXB4 acts during formation of the hemogenic endothelium (HE) from which HSCs arise. Without Runx1 induction, which arrests hematopoietic development at the HE-stage, ectopic HOXB4 expression mediated an approximately 30-fold increase in the number of circular endothelial, bona fide HE-sheets being Flk1+VE-Cadherin+Tie2+ (mean values: control: 11+/-4.8 n=7; HOXB4: 301+/-47 n=7; P<0.0001, unpaired, 2-sided Student´s t-test) and expressing Sox17 and Lmo2. This observation suggested an expansion of HE progenitors, detectable from day 5 of EB differentiation on. Determination of their frequencies within the VE-Cadherin+ population revealed a HOXB4-mediated increase from 1:360 cells (control) up to 1:15 cells (HOXB4; 95% C.I. = 1:12-1:21). After additional Runx1 induction, the endothelial cells morphologically underwent an Endothelial-to-Hematopoietic Transition (EHT) as verified at the single cell level by time-lapse microscopy. Concomitantly, they upregulated transcription of Gfi1, Gfi1b and Pu.1, initiated surface expression of the pan-hematopoietic marker CD45 and generated hematopoietic colony forming cells (CFC), thus proving their identity as real hemogenic endothelial cells. Taken together, our results strongly suggest that HOXB4 first and foremost promotes hematopoiesis by substantially increasing the number of hemogenic endothelium progenitors during mouse pluripotent stem cell differentiation. Disclosures No relevant conflicts of interest to declare.

scholarly journals 5-hydroxytryptamine synthesized in the aorta-gonad-mesonephros regulates hematopoietic stem and progenitor cell survival

2016 ◽  
Vol 214 (2) ◽  
pp. 529-545 ◽  
Author(s):  
Junhua Lv ◽  
Lu Wang ◽  
Ya Gao ◽  
Yu-Qiang Ding ◽  
Feng Liu
Keyword(s):  
Stem Cells ◽  
Tryptophan Hydroxylase ◽  
Ex Vivo ◽  
Great Promise ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells ◽  
Induced Pluripotent

The in vitro or ex vivo production of transplantable hematopoietic stem cells (HSCs) holds great promise for the treatment of hematological diseases in the clinic. However, HSCs have not been produced from either embryonic or induced pluripotent stem cells. In this study, we report that 5-hydroxytryptamine (5-HT; also called serotonin) can enhance the generation of hematopoietic stem and progenitor cells (HSPCs) in vitro and is essential for the survival of HSPCs in vivo during embryogenesis. In tryptophan hydroxylase 2–deficient embryos, a decrease in 5-HT synthesized in the aorta-gonad-mesonephros leads to apoptosis of nascent HSPCs. Mechanistically, 5-HT inhibits the AKT-Foxo1 signaling cascade to protect the earliest HSPCs in intraaortic hematopoietic clusters from excessive apoptosis. Collectively, our results reveal an unexpected role of 5-HT in HSPC development and suggest that 5-HT signaling may be a potential therapeutic target for promoting HSPC survival.

scholarly journals A Human Bone Marrow-Derived Stromal Cell Population with Hemogenic Potential

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1201-1201
Author(s):  
Saloomeh Mokhtari ◽  
Evan Joseph Colletti ◽  
Chad Sanada ◽  
Zanetta S. Lamar ◽  
Paul J Simmons ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Endothelial Cells ◽  
Conflicts Of Interest ◽  
Lymphoid Cells ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Hemogenic Endothelium ◽  
Hematopoietic Stem

Abstract During ontogeny, definitive hematopoietic stem/progenitor cells (HSC) are thought to arise from vascular endothelial cells, through an endothelial-to-hematopoietic transition, a natural process that occurs in unique, specialized embryonic hemogenic endothelial cells. Developmental studies, and experiments using pluripotent stem cells in an effort to recapitulate this process and thereby gain a better understanding of the emergence of definitive hematopoiesis, have collectively led to the prevailing view that the hemogenic endothelium constitutes a transient population of cells within the embryo that rapidly disappears during development and is absent in the adult. Herein, we provide the first evidence that at early time points of gestation, prior to the establishment of hematopoiesis, a unique subpopulation of Stro-1+ cells present within the inner part of the developing human bone marrow co-expresses APLNR, a marker of angiogenic mesoderm. Moreover, these Stro-1+APLNR+ cells express multiple other markers described for hemogenic endothelium, and subsequently contribute to the vasculature, cartilage, and bone. Importantly, we also show that cells expressing these same markers of primitive mesoderm/hemogenic endothelium persist at low frequency within the adult marrow. These adult-derived cells can be extensively expanded in vitro without loss of potential, but lack hematopoietic colony-forming potential in vitro. However, upon transplantation into a fetal microenvironment, clonally-derived populations of these adult Stro1+ isolated stromal progenitors (SIPs) not only contribute to the vasculature and nascent BM niches, but also efficiently generate, at a clonal level, hematopoietic stem cells (HSC) that are capable of robust, multilineage hematopoietic reconstitution, with generation of both myeloid and lymphoid cells upon serial transplantation. In conclusion, our studies have thus uncovered the latent potential of a highly expandable population of seemingly vestigial adult human somatic cells, whose ontogenic history includes a phenotype identical to that described for hemogenic endothelium. We have also shown that, if provided with the appropriate/necessary inductive factors, these unique adult cells are capable of giving rise to hematopoietic cells that fulfill the gold standard criteria for bona fide HSC. Therefore, these cells could potentially be more amenable to reprogramming technologies, to produce HSC that could be used to treat/cure a broad variety of blood diseases. Disclosures No relevant conflicts of interest to declare.

In Vitro Hematopoietic and Endothelial Cell Development From Cells Expressing TEK Receptor in Murine Aorta-Gonad-Mesonephros Region

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1549-1556 ◽  
Author(s):  
Isao Hamaguchi ◽  
Xu-Ling Huang ◽  
Nobuyuki Takakura ◽  
Jun-ichi Tada ◽  
Yuji Yamaguchi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Single Cell ◽  
Hematopoietic Cells ◽  
Hematopoietic Stem ◽  
Coculture System ◽  
Platelet Endothelial Cell Adhesion ◽  
Stromal Cell Line ◽  
Macrophage Colony

Abstract Recent studies have shown that long-term repopulating hematopoietic stem cells (HSCs) first appear in the aorta-gonad-mesonephros (AGM) region. Our immunohistochemistry study showed that TEK+cells existed in the AGM region. Approximately 5% of AGM cells were TEK+, and most of these were CD34+ and c-Kit+. We then established a coculture system of AGM cells using a stromal cell line, OP9, which is deficient in macrophage colony-stimulating factor (M-CSF). With this system, we showed that AGM cells at 10.5 days postcoitum (dpc) differentiated and proliferated into both hematopoietic and endothelial cells. Proliferating hematopoietic cells contained a significant number of colony-forming cells in culture (CFU-C) and in spleen (CFU-S). Among primary AGM cells at 10.5 dpc, sorted TEK+ AGM cells generated hematopoietic cells and platelet endothelial cell adhesion molecule (PECAM)-1+ endothelial cells on the OP9 stromal layer, while TEK− cells did not. When a ligand for TEK, angiopoietin-1, was added to the single-cell culture of AGM, endothelial cell growth was detected in the wells where hematopoietic colonies grew. Although the incidence was still low (1/135), we showed that single TEK+ cells generated hematopoietic cells and endothelial cells simultaneously, using a single-cell deposition system. This in vitro coculture system shows that the TEK+ fraction of primary AGM cells is a candidate for hemangioblasts, which can differentiate into both hematopoietic cells and endothelial cells.

scholarly journals The role of the PZP domain of AF10 in acute leukemia driven by AF10 translocations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Brianna J. Klein ◽  
Anagha Deshpande ◽  
Khan L. Cox ◽  
Fan Xuan ◽  
Mohamad Zandian ◽  
...  
Keyword(s):  
Critical Role ◽  
Cellular Transformation ◽  
Acute Leukemias ◽  
Hematopoietic Stem ◽  
Nucleosome Core ◽  
Stem And Progenitor Cells ◽  
Transforming Activity

AbstractChromosomal translocations of the AF10 (or MLLT10) gene are frequently found in acute leukemias. Here, we show that the PZP domain of AF10 (AF10PZP), which is consistently impaired or deleted in leukemogenic AF10 translocations, plays a critical role in blocking malignant transformation. Incorporation of functional AF10PZP into the leukemogenic CALM-AF10 fusion prevents the transforming activity of the fusion in bone marrow-derived hematopoietic stem and progenitor cells in vitro and in vivo and abrogates CALM-AF10-mediated leukemogenesis in vivo. Crystallographic, biochemical and mutagenesis studies reveal that AF10PZP binds to the nucleosome core particle through multivalent contacts with the histone H3 tail and DNA and associates with chromatin in cells, colocalizing with active methylation marks and discriminating against the repressive H3K27me3 mark. AF10PZP promotes nuclear localization of CALM-AF10 and is required for association with chromatin. Our data indicate that the disruption of AF10PZP function in the CALM-AF10 fusion directly leads to transformation, whereas the inclusion of AF10PZP downregulates Hoxa genes and reverses cellular transformation. Our findings highlight the molecular mechanism by which AF10 targets chromatin and suggest a model for the AF10PZP-dependent CALM-AF10-mediated leukemogenesis.

scholarly journals Hyperglycaemia up-regulates placental growth factor (PlGF) expression and secretion in endothelial cells via suppression of PI3 kinase-Akt signalling and activation of FOXO1

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samir Sissaoui ◽  
Stuart Egginton ◽  
Ling Ting ◽  
Asif Ahmed ◽  
Peter W. Hewett
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Endothelial Dysfunction ◽  
Akt Activation ◽  
Forkhead Box ◽  
Pi3k Activity ◽  
Binding Sequence

AbstractPlacenta growth factor (PlGF) is a pro-inflammatory angiogenic mediator that promotes many pathologies including diabetic complications and atherosclerosis. Widespread endothelial dysfunction precedes the onset of these conditions. As very little is known of the mechanism(s) controlling PlGF expression in pathology we investigated the role of hyperglycaemia in the regulation of PlGF production in endothelial cells. Hyperglycaemia stimulated PlGF secretion in cultured primary endothelial cells, which was suppressed by IGF-1-mediated PI3K/Akt activation. Inhibition of PI3K activity resulted in significant PlGF mRNA up-regulation and protein secretion. Similarly, loss or inhibition of Akt activity significantly increased basal PlGF expression and prevented any further PlGF secretion in hyperglycaemia. Conversely, constitutive Akt activation blocked PlGF secretion irrespective of upstream PI3K activity demonstrating that Akt is a central regulator of PlGF expression. Knock-down of the Forkhead box O-1 (FOXO1) transcription factor, which is negatively regulated by Akt, suppressed both basal and hyperglycaemia-induced PlGF secretion, whilst FOXO1 gain-of-function up-regulated PlGF in vitro and in vivo. FOXO1 association to a FOXO binding sequence identified in the PlGF promoter also increased in hyperglycaemia. This study identifies the PI3K/Akt/FOXO1 signalling axis as a key regulator of PlGF expression and unifying pathway by which PlGF may contribute to common disorders characterised by endothelial dysfunction, providing a target for therapy.

scholarly journals Activation of the receptor tyrosine kinase RET improves long-term hematopoietic stem cell outgrowth and potency

Blood ◽  
2020 ◽  
Vol 136 (22) ◽  
pp. 2535-2547 ◽  
Author(s):  
W. Grey ◽  
R. Chauhan ◽  
M. Piganeau ◽  
H. Huerga Encabo ◽  
M. Garcia-Albornoz ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Culture Conditions ◽  
Cellular Growth ◽  
Great Promise ◽  
Bone Marrow Niche ◽  
Hematopoietic Stem ◽  
Intracellular Signaling Pathway ◽  
Wide Range

Abstract Expansion of human hematopoietic stem cells (HSCs) is a rapidly advancing field showing great promise for clinical applications. Recent evidence has implicated the nervous system and glial family ligands (GFLs) as potential drivers of hematopoietic survival and self-renewal in the bone marrow niche; how to apply this process to HSC maintenance and expansion has yet to be explored. We show a role for the GFL receptor, RET, at the cell surface of HSCs in mediating sustained cellular growth, resistance to stress, and improved cell survival throughout in vitro expansion. HSCs treated with the key RET ligand/coreceptor complex, glial-derived neurotrophic factor and its coreceptor, exhibit improved progenitor function at primary transplantation and improved long-term HSC function at secondary transplantation. Finally, we show that RET drives a multifaceted intracellular signaling pathway, including key signaling intermediates protein kinase B, extracellular signal-regulated kinase 1/2, NF-κB, and p53, responsible for a wide range of cellular and genetic responses that improve cell growth and survival under culture conditions.

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