Differentiation potential of CD41⁺ cells derived from the mouse aorta-gonad-mesonephros region, yolk sac and embryonic circulating blood / 中华血液学杂志

<p><b>OBJECTIVE</b>To compare the differentiation ability difference of hematopoietic, mesenchymal and endothelial potential between CD41⁺ cells derived from the mouse aorta-gonadmesonephros (AGM) region, yolk sac (YS) and embryonic circulating blood (CB).</p><p><b>METHODS</b>CD41⁺ cells were sorted from AGM, YS and CB. The CD45 and c-kit expression were studied in CD41⁺ cells by flow cytometry. IL-3 and bone morphogenetic protein 4 (BMP-4) treatment together with semi solid culture were used to assess hematopoietic potential difference of CD41⁺ cells. Immunofluorescence staining of α-SMA was used to assess mesenchymal potential difference. The endothelial cell induction system was used to assess endothelial potential difference.</p><p><b>RESULTS</b>The proportions of CD45+ cells in CD41⁺ population were 51.9% (AGM), 45.8% (YS) and 22.2% (CB), respectively, while those of c-kit⁺ cells were 40.0% (AGM), 39.6% (YS) and 36.2% (CB), respectively. After stimulated by IL-3 factor, the number of total colonies increased in all three groups-derived CD41⁺ cells compared to that of unstimulated group[(14.1±1.9) vs (1.2±0.2), (32.4±1.1) vs (18.4±2.2) and (41.8±0.9) vs (10.4±1.8)], (P<0.01). After stimulated by BMP-4 factor, compared to unstimulated group, CFU-Mix colony number in CD41⁺ cells from AGM region and YS were significantly decreased[(0.5±0.6) vs (3.2±0.8), (1.3±0.7) vs (7.4±1.7)](P<0.01), but there was no difference in CB group[(2.5±0.5) vs (3.9±1.5)](P>0.01). The mesenchymal marker α-SMA was highly expressed in CD41⁺ cells from AGM region and YS, but lowly expressed in CD41⁺ cells from CB.</p><p><b>CONCLUSION</b>There are some differences between CD41⁺ cells in AGM region, YS and CB on hematopoietic cell surface marker expression, hematopoietic colony formation with IL-3 and BMP-4 stimulation.</p>

Analyzing hematopoietic development of mouse embryonic AGM region by tissue culture / 中国实验血液学杂志

To analyze hematopoietic kinetics of mouse embryonic aorta-gonad-mesonephros (AGM) region, an in vitro tissue culture method was developed in this study, partly based on previous reports. After 2 days of tissue culture, a significant number of erythro myeloid progenitors, as quantitated by colony forming assay was detected in the AGM region. Moreover, the cells from cultured E10.5 AGM region could generate 10.8 ± 3.5 colony-forming unit in spleen (CFU-S) per tissue on average. Transplantation of cultured E10.5-E11.0 AGM cells resulted in efficient (85.7% repopulated) and long-term (> 4 months) reconstitution of lethally irradiated adult recipients with remarkable chimerism [(51.12 ± 21.17)%]. The multilineage contribution of donor cells was validated by significant engraftment of myeloid and/or lymphoid cells in peripheral blood, bone marrow, spleen and thymus of recipients. Taken together, the tissue culture method can enable us to manipulate the AGM region in vitro, fulfilling a systematic evaluation of developmental kinetics of various hematopoietic precursor cells, particularly HSC, in normal and mutant mid-gestation mouse embryos.

Clarification of lymphoid potential in mouse E8.5 embryos by OP9/OP9-DL1 coculture / 中国实验血液学杂志

The anatomical location of lymphocyte ontogeny in the developing mouse embryo remains controversial. To define the site that can generate lymphocytes de novo, the intraembryonic splanchnopleura (SP) and extraembryonic yolk sac (YS) at 8.5 days postcoitum, when systemic circulation is not established, were investigated. The results indicated that in standard colony forming assay, the cells from both splanchnopleura and yolk sac formed typical myeloerythroid colonies, but their types were distinct. When cocultured with the OP9, the splanchnopleura produced B cells expressing B220, CD19 and surface IgM. Using a three-step culture protocols with the OP9 expressing Delta-like 1 as feeders, the splanchnopleura produced immature T precursor cells (CD44-/CD25+) and more mature single positive T cells (CD4+/CD8-) after 16 days of incubation. However, the yolk sac failed to generate B and T lymphocytes under identical conditions. It is concluded that prior to linked embryonic circulation, the splanchnopleura other than the yolk sac had robust lymphoid potential in vitro. In the future, more reliable evidence from novel model animals will ultimately delineate the embryonic origin of lymphocytes in vivo.

Current status of study on embryonic hematopoietic development in aorta-gonad-mesonephros -- review / 中国实验血液学杂志

Aorta-gonad-mesonephros (AGM) is well known as a main structure that de novo generates hematopoietic primary stem cells (HSC) in mid-gestation mammalian embryos. Hemogenic endothelium, and recently, subendothelial mesenchyme as well as hemangioblast are shown as contributing to blood formation in AGM region. AGM-HSC displays dynamic changes in surface markers, including CD41, CD45 and several endothelial-specific molecules. The novel finding of interleukin-3 as a potent regulator of AGM-HSC seems very interesting. Moreover, zebra fish model reveals PGE2 as a novel stimulator of HSC in AGM and kidney marrow, which is also the case in mouse hematopoietic tissues. Identification of mesenchymal stem cells with significant hematopoietic supporting capacity in AGM region suggests an alternative pathway to explore new molecules governing embryonic and adult hematopoiesis. In this paper, the hemogenic model in AGM region, surface markers on HSCs in AGM region and regulation of HSCs in AGM region were reviewed.

Separation of immortalized mesenchymal stem cell like stromal cells of mouse embryonic aorta-gonad-mesonephros region and their biological characteristics / 中国实验血液学杂志

To investigate the effects of microenvironment of aorta-gonad-mesonephros (AGM) on embryonic hematopoiesis, mesenchymal stem cell like stromal cells (MSC like stromal cells) derived from dorsal aorta (DA) in AGM region were separated and identified by their growth characteristics, related molecules expression and mesenchymal lineage potentials. Stromal cells from DA region in mouse embryos (E11.5) were isolated and cultured in vitro. After transfected by pSV3neo-SV40, the clones with G418 resistance were selected, and their growth characteristics were studied. The related molecules were analyzed by flow cytometry, and each clone was induced to differentiate into adipocytes, osteocytes, and chondrocytes. The results showed that most clones (20 clones) selected in the mouse DA region held the morphology of fibroblastoid cells. mDAF3 and mDAF18 could be grown in culture for more than 50 passages with G418 resistance, both have the potential to differentiate into adipocytes, osteocytes, and chondrocytes. At the logarithmic growth period, the cell population doubling time is about 24 hours. Surface markers, such as CD29, CD44, CD105 and Sca-1 were positively detected, while low levels of CD34, CD45, and CD31 were detected. It is concluded that immortalized mDAF3 and mDAF18 have the specific phenotype and differential potency of MSC, which suggests that MSC maybe exist in mouse embryonic DA region, where the MSC like stromal cells can be used as a cell model for further research on the modulation activity of DA microenvironment for embryonic hematopoiesis.