The Experts below are selected from a list of 183291 Experts worldwide ranked by ideXlab platform
Elaine Dzierzak - One of the best experts on this subject based on the ideXlab platform.
-
Signaling from the Sympathetic Nervous System Regulates Hematopoietic Stem Cell Emergence during Embryogenesis
Cell stem cell, 2012Co-Authors: Simon R. Fitch, Gillian M Kimber, Alexander Medvinsky, Elaine Dzierzak, Nicola K. Wilson, Aimee Parker, Bahar Mirshekar-syahkal, Berthold Göttgens, Katrin OttersbachAbstract:The first adult-repopulating hematopoietic stem cells (HSCs) emerge in the aorta-gonads-mesonephros (AGM) region of the embryo. We have recently identified the transcription factor Gata3 as being upregulated in this tissue specifically at the time of HSC emergence. We now demonstrate that the production of functional and phenotypic HSCs in the AGM is impaired in the absence of Gata3. Furthermore, we show that this effect on HSC generation is secondary to the role of Gata3 in the production of catecholamines, the mediators of the sympathetic nervous system (SNS), thus making these molecules key components of the AGM HSC niche. These findings demonstrate that the recently described functional interplay between the hematopoietic system and the SNS extends to the earliest stages of their codevelopment and highlight the fact that HSC development needs to be viewed in the context of the development of other organs.
-
Interleukin-1 regulates hematopoietic progenitor and stem cells in the midgestation mouse fetal liver
Haematologica, 2009Co-Authors: Claudia Orelio, Esther Haak, Marian Peeters, Karin Van Der Horn, Elaine DzierzakAbstract:Background Hematopoietic progenitors are generated in the yolk sac and Aorta-Gonad-Mesonephros region during early mouse development. At embryonic day 10.5 the first hematopoietic stem cells emerge in the Aorta-Gonad-Mesonephros. Subsequently, hematopoietic stem cells and progenitors are found in the fetal liver. The fetal liver is a potent hematopoietic site, playing an important role in the expansion and differentiation of hematopoietic progenitors and hematopoietic stem cells. However, little is known concerning the regulation of fetal liver hematopoietic stem cells. In particular, the role of cytokines such as interleukin-1 in the regulation of hematopoietic stem cells in the embryo has been largely unexplored. Recently, we observed that the adult pro-inflammatory cytokine interleukin-1 is involved in regulating Aorta-Gonad-Mesonephros hematopoietic progenitor and hematopoietic stem cell activity. Therefore, we set out to investigate whether interleukin-1 also plays a role in regulating fetal liver progenitor cells and hematopoietic stem cells. Design and Methods We examined the interleukin-1 ligand and receptor expression pattern in the fetal liver. The effects of interleukin-1 on hematopoietic progenitor cells and hematopoietic stem cells were studied by FACS and transplantation analyses of fetal liver explants, and in vivo effects on hematopoietic stem cell and progenitors were studied in Il1r1−/− embryos. Results We show that fetal liver hematopoietic progenitor cells express the IL-1RI and that interleukin-1 increases fetal liver hematopoiesis, progenitor cell activity and promotes hematopoietic cell survival. Moreover, we show that in Il1r1−/− embryos, hematopoietic stem cell activity is impaired and myeloid progenitor activity is increased. Conclusions The IL-1 ligand and receptor are expressed in the midgestation liver and act in the physiological regulation of fetal liver hematopoietic progenitor cells and hematopoietic stem cells.
-
Interleukin-1 mediated hematopoietic cell regulation in the Aorta-Gonad-Mesonephros region of the mouse embryo
Blood, 2008Co-Authors: Claudia Orelio, Esther Haak, Marian Peeters, Elaine DzierzakAbstract:Hematopoiesis during development is a dynamic process, with many factors involved in the emergence and regulation of hematopoietic stem cells (HSCs) and progenitor cells. Whereas previous studies have focused on developmental signaling and transcription factors in embryonic hematopoiesis, the role of well-known adult hematopoietic cytokines in the embryonic hematopoietic system has been largely unexplored. The cytokine interleukin-1 (IL-1), best known for its proinflammatory properties, has radioprotective effects on adult bone marrow HSCs, induces HSC mobilization, and increases HSC proliferation and/or differentiation. Here we examine IL-1 and its possible role in regulating hematopoiesis in the midgestation mouse embryo. We show that IL-1, IL-1 receptors (IL-1Rs), and signaling mediators are expressed in the Aorta-Gonad-Mesonephros (AGM) region during the time when HSCs emerge in this site. IL-1 signaling is functional in the AGM, and the IL-1RI is expressed ventrally in the aortic subregion by some hematopoietic, endothelial, and mesenchymal cells. In vivo analyses of IL-1RI–deficient embryos show an increased myeloid differentiation, concomitant with a slight decrease in AGM HSC activity. Our results suggest that IL-1 is an important homeostatic regulator at the earliest time of HSC development, acting to limit the differentiation of some HSCs along the myeloid lineage.
-
Analysis and manipulation of hematopoietic progenitor and stem cells from murine embryonic tissues.
Current protocols in stem cell biology, 2008Co-Authors: Alexander Medvinsky, Samir Taoudi, Sandra Mendes, Elaine DzierzakAbstract:Hematopoietic development begins in several locations in the mammalian embryo: yolk sac, Aorta-Gonad-Mesonephros region (AGM), and the chorio-allantoic placenta. Generation of the most potent cells, adult definitive hematopoietic stem cells (HSCs), occurs within the body of the mouse embryo at midgestation in the AGM region. Similarly, at the equivalent developmental time in the human embryo, the AGM region has been shown to contain multipotent progenitors. Hence, the mouse embryo serves as an excellent model to study hematopoietic development. To further studies on the ontogeny of the adult hematopoietic system, the focus of this unit is on the experimental methods used in analysis of the AGM region.
-
Current Protocols in Stem Cell Biology - Analysis and manipulation of hematopoietic progenitor and stem cells from murine embryonic tissues.
Current Protocols in Stem Cell Biology, 2008Co-Authors: Alexander Medvinsky, Samir Taoudi, Sandra C. Mendes, Elaine DzierzakAbstract:Hematopoietic development begins in several locations in the mammalian embryo: yolk sac, Aorta-Gonad-Mesonephros region (AGM), and the chorio-allantoic placenta. Generation of the most potent cells, adult definitive hematopoietic stem cells (HSCs), occurs within the body of the mouse embryo at midgestation in the AGM region. Similarly, at the equivalent developmental time in the human embryo, the AGM region has been shown to contain multipotent progenitors. Hence, the mouse embryo serves as an excellent model to study hematopoietic development. To further studies on the ontogeny of the adult hematopoietic system, the focus of this unit is on the experimental methods used in analysis of the AGM region.
Alexander Medvinsky - One of the best experts on this subject based on the ideXlab platform.
-
Highly potent human haemopoietic stem cells first emerge in the intraembryonic Aorta-Gonad-Mesonephros region
The Lancet, 2013Co-Authors: Andrejs Ivanovs, Stanislav Rybtsov, Lindsey Welch, Richard A. Anderson, Marc Turner, Alexander MedvinskyAbstract:Abstract Background Haemopoietic stem cells (HSCs) are used in the clinic to treat various haematological disorders. These cells emerge during early embryogenesis and maintain haemopoiesis in the adult organism. In the vertebrate embryo, HSCs develop in multiple locations. Little is known about the embryonic development of human HSCs. Methods Human embryonic and fetal tissues were obtained after elective termination of pregnancy. Preconditioned immunodeficient mice were used as recipients for human HSCs. Transplanted mice were bled every 1–2 months to assess human HSC contribution. Findings We have found that human HSCs emerge first in the Aorta-Gonad-Mesonephros (AGM) region and only later appear in the yolk sac, liver, and placenta. Transplantation of human AGM region cells into immunodeficient mice provides long-term high-level multilineage haemopoietic repopulation. We have shown that, despite the low number of HSCs in the human AGM region, their self-renewal potential is enormous. A single HSC derived from the AGM region generates around 600 daughter HSCs in primary recipients, which disseminate throughout the entire recipient bone marrow and are retransplantable. Interpretation We provide a systematic spatiotemporal analysis of HSC emergence in the early human embryo and identify the AGM region as the primary source of powerful HSCs with enormous self-renewal capacity. This high potency of the first HSCs sets a new standard for in-vitro generation of HSCs from pluripotent stem cells for the purpose of regenerative medicine. Funding UK Medical Research Council.
-
Signaling from the Sympathetic Nervous System Regulates Hematopoietic Stem Cell Emergence during Embryogenesis
Cell stem cell, 2012Co-Authors: Simon R. Fitch, Gillian M Kimber, Alexander Medvinsky, Elaine Dzierzak, Nicola K. Wilson, Aimee Parker, Bahar Mirshekar-syahkal, Berthold Göttgens, Katrin OttersbachAbstract:The first adult-repopulating hematopoietic stem cells (HSCs) emerge in the aorta-gonads-mesonephros (AGM) region of the embryo. We have recently identified the transcription factor Gata3 as being upregulated in this tissue specifically at the time of HSC emergence. We now demonstrate that the production of functional and phenotypic HSCs in the AGM is impaired in the absence of Gata3. Furthermore, we show that this effect on HSC generation is secondary to the role of Gata3 in the production of catecholamines, the mediators of the sympathetic nervous system (SNS), thus making these molecules key components of the AGM HSC niche. These findings demonstrate that the recently described functional interplay between the hematopoietic system and the SNS extends to the earliest stages of their codevelopment and highlight the fact that HSC development needs to be viewed in the context of the development of other organs.
-
Highly potent human hematopoietic stem cells first emerge in the intraembryonic Aorta-Gonad-Mesonephros region
The Journal of experimental medicine, 2011Co-Authors: Andrejs Ivanovs, Stanislav Rybtsov, Lindsey Welch, Richard A. Anderson, Marc Turner, Alexander MedvinskyAbstract:Hematopoietic stem cells (HSCs) emerge during embryogenesis and maintain hematopoiesis in the adult organism. Little is known about the embryonic development of human HSCs. We demonstrate that human HSCs emerge first in the Aorta-Gonad-Mesonephros (AGM) region, specifically in the dorsal aorta, and only later appear in the yolk sac, liver, and placenta. AGM region cells transplanted into immunodeficient mice provide long-term high level multilineage hematopoietic repopulation. Human AGM region HSCs, although present in low numbers, exhibit a very high self-renewal potential. A single HSC derived from the AGM region generates at least 300 daughter HSCs in primary recipients, which disseminate throughout the entire recipient bone marrow and are retransplantable. These findings highlight the vast regenerative potential of the earliest human HSCs and set a new standard for in vitro generation of HSCs from pluripotent stem cells for the purpose of regenerative medicine.
-
Hematopoietic stem cell activity in the Aorta-Gonad-Mesonephros region enhances after mid-day 11 of mouse development.
The International journal of developmental biology, 2010Co-Authors: Erin Taylor, Samir Taoudi, Alexander MedvinskyAbstract:The E11.5 Aorta-Gonad-Mesonephros (AGM) region is a site of hematopoietic stem cell (HSC) development prior to colonisation of the embryonic liver. The generation of HSCs in the embryo starting from E11 is very rapid. Here, we have assessed hematopoietic development in the AGM region during E11 at precise somitic ages. Although the numbers of committed hematopoietic precursors fluctuate throughout the day, the repopulation activity in the AGM region noticeably increases from mid (44 s.p.) to end (48 s.p.) day 11 of gestation. While prior to mid day 11 two thirds of AGM regions contain no definitive HSCs, shortly prior to liver colonisation, all older day 11 embryos contain definitive HSC. Nevertheless, all E11 AGM regions even at early somitic stages have the capacity to expand numbers of definitive HSCs ex vivo. Quantitative anatomical analysis confirmed preferential localization of intra-aortic clusters (IACs) to the ventral domain of the dorsal aorta during entire day 11 of development. No clear correlation was established between IAC numbers and the presence of definitive HSCs.
-
Current Protocols in Stem Cell Biology - Analysis and manipulation of hematopoietic progenitor and stem cells from murine embryonic tissues.
Current Protocols in Stem Cell Biology, 2008Co-Authors: Alexander Medvinsky, Samir Taoudi, Sandra C. Mendes, Elaine DzierzakAbstract:Hematopoietic development begins in several locations in the mammalian embryo: yolk sac, Aorta-Gonad-Mesonephros region (AGM), and the chorio-allantoic placenta. Generation of the most potent cells, adult definitive hematopoietic stem cells (HSCs), occurs within the body of the mouse embryo at midgestation in the AGM region. Similarly, at the equivalent developmental time in the human embryo, the AGM region has been shown to contain multipotent progenitors. Hence, the mouse embryo serves as an excellent model to study hematopoietic development. To further studies on the ontogeny of the adult hematopoietic system, the focus of this unit is on the experimental methods used in analysis of the AGM region.
Tetsuya Taga - One of the best experts on this subject based on the ideXlab platform.
-
Thrombopoietin contributes to the formation and the maintenance of hematopoietic progenitor-containing cell clusters in the Aorta-Gonad-Mesonephros region.
Cytokine, 2017Co-Authors: Kaho Harada, Ikuo Nobuhisa, Maha Anani, Kiyoka Saito, Tetsuya TagaAbstract:In the midgestation mouse embryo, hematopoietic cell clusters containing hematopoietic stem/progenitor cells arise in the Aorta-Gonad-Mesonephros (AGM) region. We have previously reported that forced expression of the Sox17 transcription factor in CD45lowc-Kithigh AGM cells, which are the hematopoietic cellular component of the cell clusters, and subsequent coculture with OP9 stromal cells in the presence of three cytokines, stem cell factor (SCF), interleukin-3 (IL-3), and thrombopoietin (TPO), led to the formation and the maintenance of cell clusters with cells at an undifferentiated state in vitro. In this study, we investigated the role of each cytokine in the formation of hematopoietic cell clusters. We cultured Sox17-transduced AGM cells with each of the 7 possible combinations of the three cytokines. The size and the number of Sox17-transduced cell clusters in the presence of TPO, either alone or in combination, were comparable to that observed with the complete set of the three cytokines. Expression of TPO receptor, c-Mpl was almost ubiquitously expressed and maintained in Sox17-transduced hematopoietic cell clusters. In addition, the expression level of c-Mpl was highest in the CD45lowc-Kithigh cells among the Sox17-transduced cell clusters. Moreover, c-Mpl protein was highly expressed in the intra-aortic hematopoietic cell clusters in comparison with endothelial cells of dorsal aorta. Finally, stimulation of the endothelial cells prepared from the AGM region by TPO induced the production of hematopoietic cells. These results suggest that TPO contributes to the formation and the maintenance of hematopoietic cell clusters in the AGM region.
-
CD45lowc-Kithigh cells have hematopoietic properties in the mouse Aorta-Gonad-Mesonephros region
Experimental cell research, 2012Co-Authors: Ikuo Nobuhisa, Shoutarou Yamasaki, Ahmed Ramadan, Tetsuya TagaAbstract:Long-term reconstituting hematopoietic stem cells first arise from the aorta of the Aorta-Gonad-Mesonephros (AGM) region in a mouse embryo. We have previously reported that in cultures of the dispersed AGM region, CD45(low)c-Kit(+) cells possess the ability to reconstitute multilineage hematopoietic cells, but investigations are needed to show that this is not a cultured artifact and to clarify when and how this population is present. Based on the expression profile of CD45 and c-Kit in freshly dissociated AGM cells from embryonic day 9.5 (E9.5) to E12.5 and aorta cells in the AGM from E13.5 to E15.5, we defined six cell populations (CD45(-)c-Kit(-), CD45(-)c-Kit(low), CD45(-)c-Kit(high), CD45(low)c-Kit(high), CD45(high)c-Kit(high), and CD45(high)c-Kit(very low)). Among these six populations, CD45(low)c-Kit(high) cells were most able to form hematopoietic cell colonies, but their ability decreased after E11.5 and was undetectable at E13.5 and later. The CD45(low)c-Kit(high) cells showed multipotency in vitro. We demonstrated further enrichment of hematopoietic activity in the Hoechst dye-effluxing side population among the CD45(low)c-Kit(high) cells. Here, we determined that CD45(low)c-Kit(high) cells arise from the lateral plate mesoderm using embryonic stem cell-derived differentiation system. In conclusion, CD45(low)c-Kit(high) cells are the major hematopoietic cells of mouse AGM.
-
Identification of a population of cells with hematopoietic stem cell properties in mouse Aorta-Gonad-Mesonephros cultures.
Experimental cell research, 2007Co-Authors: Ikuo Nobuhisa, Naoki Ohtsu, Seiji Okada, Naomi Nakagata, Tetsuya TagaAbstract:The aorta–gonad–mesonephros (AGM) region is a primary source of definitive hematopoietic cells in the midgestation mouse embryo. In cultures of dispersed AGM regions, adherent cells containing endothelial cells are observed first, and then non-adherent hematopoietic cells are produced. Here we report on the characterization of hematopoietic cells that emerge in the AGM culture. Based on the expression profiles of CD45 and c-Kit, we defined three cell populations: CD45low c-Kit+ cells that had the ability to form hematopoietic cell colonies in methylcellulose media and in co-cultures with stromal cells; CD45low c-Kit− cells that showed a granulocyte morphology; CD45high c-Kitlow/− that exhibited a macrophage morphology. In co-cultures of OP9 stromal cells and freshly prepared AGM cultures, CD45low c-Kit+ cells from the AGM culture had the abilities to reproduce CD45low c-Kit+ cells and differentiate into CD45low c-Kit− and CD45high c-Kitlow/− cells, whereas CD45low c-Kit− and CD45high c-Kitlow/− did not produce CD45low c-Kit+ cells. Furthermore, CD45low c-Kit+ cells displayed a long-term repopulating activity in adult hematopoietic tissue when transplanted into the liver of irradiated newborn mice. These results indicate that CD45low c-Kit+ cells from the AGM culture have the potential to reconstitute multi-lineage hematopoietic cells.
-
Inhibitory effects of homeodomain-interacting protein kinase 2 on the Aorta-Gonad-Mesonephros hematopoiesis.
Experimental cell research, 2006Co-Authors: Naoki Ohtsu, Ikuo Nobuhisa, Miyuki Mochita, Tetsuya TagaAbstract:Abstract Definitive hematopoiesis starts in the aorta–gonad–mesonephros (AGM) region of the mouse embryo. Our previous studies revealed that STAT3, a gp130 downstream transcription factor, is required for AGM hematopoiesis and that homeodomain-interacting protein kinase 2 (HIPK2) phosphorylates serine-727 of STAT3. HIPK2 is a serine/threonine kinase known to be involved in transcriptional repression and apoptosis. In the present study, we examined the role of HIPK2 in hematopoiesis in mouse embryo. HIPK2 transcripts were found in fetal hematopoietic tissues such as the mouse AGM region and fetal liver. In cultured AGM cells, HIPK2 protein was detected in adherent cells. Functional analyses of HIPK2 were carried out by introducing wild-type and mutant HIPK2 constructs into AGM cultures. Production of CD45+ hematopoietic cells was suppressed by forced expression of HIPK2 in AGM cultures. This suppression required the kinase domain and nuclear localization signals of HIPK2, but the kinase activity was dispensable. HIPK2-overexpressing AGM-derived nonadherent cells did not form cobblestone-like colonies in cultures with stromal cells. Furthermore, overexpression of HIPK2 in AGM cultures impeded the expansion of CD45lowc-Kit+ cells, which exhibit the immature hematopoietic progenitor phenotype. These data indicate that HIPK2 plays a negative regulatory role in AGM hematopoiesis in the mouse embryo.
-
Fetal Hematopoietic Development in the Mouse Aorta-Gonad-Mesonephros Region Is Inhibited by Homeodomain-Interacting Protein Kinase 2.
Blood, 2005Co-Authors: Naoki Ohtsu, Ikuo Nobuhisa, Miyuki Mochita, Tetsuya TagaAbstract:Definitive hematopoiesis starts in the Aorta-Gonad-Mesonephros (AGM) region of mouse embryo. Our previous studies showed that STAT3, a gp130 downstream transcription factor, is required for AGM hematopoiesis and that homeodomain-interacting protein kinase 2 (HIPK2) phosphorylates serine 727 of STAT3. HIPK2 is a serine/threonine kinase known to be involved in transcriptional repression and apoptosis. In the present study, we examined the role of HIPK2 in the hematopoietic development. HIPK2 transcripts were found in the fetal hematopoietic tissues such as the AGM region at embryonic day (E) 10.5 and E11.5 and the E14.5 fetal liver as detected by RT-PCR and whole mount in situ hybridization. The functional analysis of HIPK2 was done by introducing wild-type and its mutant constructs into the primary culture of the mouse AGM region. Retrovirus mediated forced expression of HIPK2 with green fluorescent protein (GFP) in the AGM culture remarkably inhibited the emergence of GFP + nonadherent cells. In coculture of virus-infected GFP + nonadherent cells with OP9 stromal cells, no cobblestone-like area-forming colonies were detected in the HIPK2-infected cells, while control GFP virus had no effect on the colony formation. Similarly, when GFP + nonadherent cells were sorted and cultured in semisolid medium, colonies were not formed from the HIPK2-GFP virus-infected AGM culture. These data suggest that HIPK2 suppresses differentiation of adherent endothelial-like cells to colony-forming hematopoietic cells or, alternatively HIPK2 inhibits proliferation of newly developed hematopoietic progenitors. Development of cells positive for CD45 (an immature hematopoietic cell maker) cells was suppressed by forced expression of HIPK2 in the AGM culture. To determine the domain important for the inhibitory activity of HIPK2, we constructed a series of point and deletion mutants. Overexpression of HIPK2 mutants in the AGM culture showed that a certain structure of the kinase domain as well as its C-terminally located structure but not the kinase activity is essential for the HIPK2-mediated inhibition of hematopoiesis. When nonadherent cells in the AGM culture were fractionated for their expression levels of CD45 and c-Kit (a receptor for stem cell factor), CD45 low c-Kit + cells have a potential to form hematopoietic cell colonies. In the HIPK2-overexpressed AGM culture, emergence of CD45 low c-Kit + cells was significantly inhibited. These data indicated that HIPK2 plays a negative regulatory role in the development of AGM hematopoiesis in mouse embryo.
Takahiko Hara - One of the best experts on this subject based on the ideXlab platform.
-
Cultivation of Aorta-Gonad-Mesonephros-derived hematopoietic stem cells in the fetal liver microenvironment amplifies long-term repopulating activity and enhances engraftment to the bone marrow.
Blood, 2002Co-Authors: Masaki Takeuchi, Takashi Sekiguchi, Takahiko Hara, Taisei Kinoshita, Atsushi MiyajimaAbstract:During mammalian development, definitive hematopoietic stem cells (HSCs) arise in the Aorta-Gonad-Mesonephros (AGM) region and colonize the fetal liver (FL) before hematopoiesis occurs in the bone marrow. The FL is a unique hematopoietic organ where both HSCs and mature blood cells are actively generated along with functional maturation of hepatic cells as a metabolic organ. To characterize HSCs and FL microenvironments during development, this study establishes a coculture system composed of AGM-originated HSCs and FL nonhematopoietic cells. The results demonstrate that FL cells support significant expansion of lineage-committed hematopoietic cells as well as immature progenitors. More important, long-term repopulating activity was amplified from AGM-originated HSCs in this coculture system. Engraftment of HSCs to the bone marrow was strongly enhanced by coculture. In addition, AGM HSCs produced significantly more hematopoietic cells than E14.5 and E18.5 FL HSCs in vitro. These results suggest that the FL microenvironment not only stimulates expansion of the hematopoietic system, but also possibly modifies the characteristics of AGM HSCs. Thus, this coculture system recapitulates the developmental process of HSCs and the FL microenvironment and provides a novel means to study the development of hematopoiesis.
-
In vivo differentiation of stem cells in the Aorta-Gonad-Mesonephros region of mouse embryo and adult bone marrow.
Experimental hematology, 2002Co-Authors: Hiroshi Tamura, Atsushi Miyajima, Ken Iwatsuki, Kiyoko Tanaka, Shiki Okamoto, Yuki Nakayama, Yoshiki Futamata, Takahiko HaraAbstract:Abstract Objective Hematopoietic stem cells (HSCs) are thought to be generated from hemangioblasts, the common precursor cells for blood and endothelial cells, in the Aorta-Gonad-Mesonephros (AGM) region of the mouse embryo. The genetic program of HSCs was recently demonstrated to be plastic, but the potential for AGM-region hemangioblasts to be transplanted and to differentiate in vivo has not been well described. Here we examined the fate of donor cells in mice transplanted with CD45 − AGM cells, which presumably include hemangioblasts. Materials and Methods CD45 − cells in the AGM region of embryos at 11.5 days post coitum or CD45 + CD34 − side population (SP) of cells in adult bone marrow (BM) derived from enhanced green fluorescent protein transgenic mice were transplanted into the liver of busulfan-treated neonatal mice. Two to 6 months after injection of the cells, the contribution of donor-derived cells in the hematopoietic compartment and in various organs was analyzed by flow cytometry and confocal microscopy. Results CD45 − cells from the AGM region not only generated peripheral blood cells but also differentiated into endothelial and other nonhematopoietic cells in liver, kidney, lung, small intestine, and uterus in transplanted mice. A similar engrafting pattern was observed in the small intestine of mice transplanted with BM SP/CD45 + cells, secondary BM-transplanted mice, and lethally irradiated adult mice that received intravenous injections of BM cells. Conclusion A CD45 − fraction of the AGM region and CD45 + BM stem cells share the same in vivo potential to differentiate into hematopoietic, endothelial, smooth muscle, and stroma-like cells when transplanted in mice.
-
The AML1 transcription factor functions to develop and maintain hematogenic precursor cells in the embryonic Aorta-Gonad-Mesonephros region.
Developmental biology, 2000Co-Authors: Yoh Suke Mukouyama, Takahiko Hara, Atsushi Miyajima, Natsuko Chiba, Masanobu Satake, Yoshiaki Ito, Hitoshi Okada, Ryunosuke Kanamaru, Toshio WatanabeAbstract:Abstract We examined the role of the AML1 transcription factor in the development of hematopoiesis in the paraaortic splanchnopleural (P-Sp) and the aorta–gonad–mesonephros (AGM) regions of mouse embryos. The activity of colony-forming units of colonies from the P-Sp/AGM region was reduced severalfold by heterozygous disruption of the AML1 gene, indicating that AML1 functioned in a dosage-dependent manner to generate hematopoietic progenitors. In addition, no hematopoietic progenitor activity was detected in the P-Sp/AGM region of embryos with an AML1 null mutation. Similar results were obtained when a dispersed culture was first prepared from the P-Sp/AGM region before assay of the activity of the colony-forming units. In a culture of cells with the AML1(+/+) genotype, both hematopoietic and endothelial-like cell types emerged, but in a culture of cells with the AML1(−/−) genotype, only endothelial-like cells emerged. Interestingly, introduction of AML1 cDNA into the P-Sp/AGM culture with the AML1(−/−) genotype partially restored the production of hematopoietic cells. This restoration was observed for cultures prepared from 9.5-day postcoitum (dpc) embryos but not for cultures prepared from 11.5-dpc embryos. Therefore, the population of endothelial-like cells capable of growing in the AML1(−/−) culture would appear to contain inert but nonetheless competent hematogenic precursor cells up until at least the 9.5-dpc period. All these results support the notion that the AML1 transcription factor functions to develop and maintain hematogenic precursor cells in the embryonic P-Sp/AGM region.
-
Identification of Podocalyxin-like Protein 1 as a Novel Cell Surface Marker for Hemangioblasts in the Murine Aorta-Gonad-Mesonephros Region
Immunity, 1999Co-Authors: Takahiko Hara, Yoh Ko Nakano, Ken Ichi Minehata, Takashi Sekiguchi, Masaru Okabe, Nancy A Jenkins, Neal G Copeland, Minoru Tanaka, Kazuhiro Tamura, Hiroshi KogoAbstract:Abstract Recent studies with avian embryos and murine embryonic stem cells have suggested that hematopoietic cells are derived from hemangioblasts, the common precursors of hematopoietic and endothelial cells. We molecularly cloned podocalyxin-like protein 1 (PCLP1) as a novel surface marker for endothelial-like cells in the Aorta-Gonad-Mesonephros (AGM) region of mouse embryos, where long-term repopulating hematopoietic stem cells (LTR-HSCs) are known to arise. PCLP1 + CD45 − cells in the AGM region incorporated acetylated low-density lipoprotein and produced both hematopoietic and endothelial cells when cocultured with OP9 stromal cells. Moreover, multiple lineages of hematopoietic cells were generated in vivo when PCLP1 + CD45 − cells were injected into neonatal liver of busulfan-treated mice. Thus, PCLP1 can be used to separate hemangioblasts that give rise to LTR-HSCs.
-
Hematopoietic cells in cultures of the murine embryonic Aorta-Gonad-Mesonephros region are induced by c-Myb.
Current biology : CB, 1999Co-Authors: Yoh Suke Mukouyama, Takahiko Hara, Atsushi Miyajima, Natsuko Chiba, Michael Mucenski, Masanobu Satake, Toshio WatanabeAbstract:Abstract Definitive hematopoiesis begins in the para-aortic, splanchnopleural (P-Sp) and aorta–gonad–mesonephros (AGM) regions of mouse embryos and then switches to the fetal liver [1–3]. Gene-targeted mice lacking the c-Myb transcription factor have severe hematopoietic defects in the fetal liver [4]. The role of c-Myb, if any, in P-Sp/AGM hematopoiesis has not been examined, however. Recently, we reported that oncostatin M can effectively expand both hematopoietic and endothelial-like cells from in vitro cultures of the AGM region [5]. Using this cell culture system, we examined the involvement of c-Myb in definitive hematopoiesis in the P-Sp and AGM regions. When primary cultures from the P-Sp or AGM regions of wild-type mouse embryos were probed with an anti-c-Myb antibody, hematopoietic cells but not endothelial-like cells showed positive staining. In contrast, in the P-Sp/AGM culture from c- myb −/− embryos, no hematopoietic cells were generated and endothelial-like cells predominated, indicating that the impairment of hematopoiesis in the liver of c- myb −/− embryos is actually preceded by a defect in P-Sp/AGM hematopoiesis. Hematogenic precursor cells were, however, still present in an inert but competent form among the endothelial-like, adherent cell population of c- myb −/− P-Sp/AGM cultures. When infected with a retrovirus carrying c- myb cDNA, these cultures gave rise to a significant number of hematopoietic cells. The rescued cells, unlike wild-type hematopoietic cells, were negative for c-Kit (a marker of hematopoietic progenitors), but did express other hematopoietic cell surface markers such as Mac-1, Gr-1 (myeloid markers), CD19, B220, Thy-1.2 (Iymphoid markers), and Ter119 (an erythroid marker). Thus, c-Myb plays a role in the generation of hematopoietic cells in the embryonic P-Sp and AGM regions.
Tatsutoshi Nakahata - One of the best experts on this subject based on the ideXlab platform.
-
Biomimetic Aorta-Gonad-Mesonephros-on-a-Chip to study human developmental hematopoiesis.
Biomedical microdevices, 2020Co-Authors: Ryohichi Sugimura, Ryo Ohta, Chihiro Mori, Takafumi Mano, Emi Sano, Kaori Kosugi, Tatsutoshi Nakahata, Akira Niwa, Megumu K SaitoAbstract:A fundamental limitation in the derivation of hematopoietic stem and progenitor cells is the imprecise understanding of human developmental hematopoiesis. Herein we established a multilayer microfluidic Aorta-Gonad-Mesonephros (AGM)-on-a-chip to emulate developmental hematopoiesis from pluripotent stem cells. The device consists of two layers of microchannels separated by a semipermeable membrane, which allows the co-culture of human hemogenic endothelial (HE) cells and stromal cells in a physiological relevant spatial arrangement to replicate the structure of the AGM. HE cells derived from human induced pluripotent stem cells (hiPSCs) were cultured on a layer of mesenchymal stromal cells in the top channel while vascular endothelial cells were co-cultured on the bottom side of the membrane within the microfluidic device. We show that this AGM-on-a-chip efficiently derives endothelial-to-hematopoietic transition (EHT) from hiPSCs compared with regular suspension culture. The presence of mesenchymal stroma and endothelial cells renders functional HPCs in vitro. We propose that the AGM-on-a-chip could serve as a platform to dissect the cellular and molecular mechanisms of human developmental hematopoiesis.
-
biomimetic aorta gonad mesonephros on a chip to study human developmental hematopoiesis
bioRxiv, 2019Co-Authors: Ryohichi Sugimura, Ryo Ohta, Chihiro Mori, Takafumi Mano, Emi Sano, Kaori Kosugi, Tatsutoshi Nakahata, Akira Niwa, Megumu K Saito, Yusuke TorisawaAbstract:ABSTRACT A fundamental limitation in the derivation of hematopoietic stem and progenitor cells is the imprecise understanding of human developmental hematopoiesis. Herein we established a multilayer microfluidic Aorta-Gonad-Mesonephros (AGM)-on-a-chip to emulate developmental hematopoiesis from human pluripotent stem cells. We show that the AGM-chip efficiently derives endothelial to hematopoietic transition (EHT) in the presence of both mesenchymal stroma and endothelial cells. The AGM-chip could dissect the cellular and molecular mechanisms of human developmental hematopoiesis.
-
Expression profile analysis of Aorta-Gonad-Mesonephros region-derived stromal cells reveals genes that regulate hematopoiesis.
Biochemical and biophysical research communications, 2008Co-Authors: Kenji Nagao, Tomoyuki Tahara, Atsushi Hinohara, Takayuki Ohta, Tetsuya Hagiwara, Yoshitake Maeda, Takashi Yoneya, Yoshiaki Sohma, Toshio Heike, Tatsutoshi NakahataAbstract:The Aorta-Gonad-Mesonephros (AGM) region is involved in the generation and maintenance of the first definitive hematopoietic stem cells (HSCs). A mouse AGM-derived cell line, AGM-S3, was shown to support the development of HSCs. To elucidate the molecular mechanisms regulating early hematopoiesis, we obtained subclones from AGM-S3, one of which was hematopoiesis supportive (S3-A9) and the other one of which was non-supportive (S3-A7), and we analyzed their gene expression profiles by gene chip analysis. In the present study, we found that Glypican-1 (GPC1) was highly expressed in the supportive subclone AGM-S3-A9. Over-expression of GPC1 in non-supportive cells led to the proliferation of progenitor cells in human cord blood when cocultured with the transfected-stromal cells. Thus, GPC1 may have an important role in the establishment of a microenvironment that supports early events in hematopoiesis.
-
Role of the microenvironment of the embryonic Aorta-Gonad-Mesonephros region in hematopoiesis.
Annals of the New York Academy of Sciences, 2006Co-Authors: Mitsuo Nishikawa, Tatsutoshi Nakahata, Tomoyuki Tahara, Atsushi Hinohara, Atushi Miyajima, Akihiro ShimosakaAbstract:Although various cytokines, growth factors, and chemokines are known to regulate hematopoiesis, expansion of hematopoietic stem cells (HSCs) in vitro with the use of such agents has proved problematic. Stromal cells are major components of the microenvironment that surrounds hematopoietic cells and are thought to play an important role in hematopoiesis in vivo. Co-culture of HSCs with stromal cells promotes hematopoiesis and self-renewal of HSCs. Definitive hematopoietic cells first appear during mammalian embryonic development in the Aorta-Gonad-Mesonephros (AGM) region, and it is therefore thought that the microenvironment of this region plays an important role in HSC ontogeny. We have adopted two approaches to studying the contribution of the AGM microenvironment to hematopoiesis. In the first approach, we have developed an in vitro culture system for mouse AGM explants. Hematopoiesis is enhanced in such cultures by the presence of the combination of stem cell factor (SCF), basic fibroblast growth factor, leukemia inhibitory factor, and oncostatin M (SFLO culture). However, transplantation assays revealed that HSCs capable of long-term reconstitution of the hematopoietic compartment of irradiated mice (LTR-HSCs) do not expand in AGM-SFLO cultures; rather, these cultures appear to provide a favorable microenvironment for hematogenic angioblasts that are precursors of both endothelial and hematopoietic cells. In our second approach, we have established various stromal cell lines from the mouse AGM region. The AGM-S3 cell line supports human and mouse primitive hematopoietic cells as well as mouse LTR-HSCs. Maintenance of LTR-HSCs is mediated by a mechanism other than SCF signaling through its receptor (c-Kit). These two in vitro approaches should prove useful for further elucidation of the mechanisms that underlie hematopoiesis and HSC self-renewal.
-
In Vitro Expansion of Murine Multipotential Hematopoietic Progenitors from the Embryonic Aorta–Gonad–Mesonephros Region
Immunity, 1998Co-Authors: Yoh Suke Mukouyama, Hiroshi Kogo, Takahiko Hara, Kazuhiro Tamura, Tatsutoshi Nakahata, Kohichiro Tsuji, Peter J. Donovan, Hee-jung Kim, Atsushi MiyajimaAbstract:Abstract The origin of hematopoietic stem cells (HSCs) and their growth factor requirement are poorly understood. Here we describe a new in vitro culture system of the aorta–gonad–mesonephros (AGM) region, where long-term repopulating HSCs first arise. We demonstrate that oncostatin M (OSM) is expressed in the AGM and is absolutely required for the expansion of multipotential hematopoietic progenitors in vitro. In addition, OSM enhances the formation of endothelial cell clusters. Thus, OSM appears to be a key cytokine for the development of multipotential hematopoietic progenitors in the AGM, possibly acting on common precursor cells between HSCs and endothelial cells. By using the AGM culture derived from macrophage colony-stimulating factor (M-CSF)–deficient op/op mutant embryos, we also show a pivotal role for M-CSF in fetal myelopoiesis.