Generation of definitive hematopoietic stem cells from murine early yolk sac and paraaortic splanchnopleures by aorta-gonad-mesonephros region–derived stromal cells

Abstract

There is controversy as to whether murine definitive hematopoiesis originates from yolk sac (YS) or the intraembryonic region. This study reports the generation of definitive hematopoietic stem cells

Generation of functional erythrocytes from human embryonic stem cell-derived definitive hematopoiesis

“…In murine experiments, successful transplantation of YS hematopoietic cells directly into adult recipients is difficult, indicating that the YS cells differ from adult-type hematopoietic cells. However, YS-derived hematopoietic stem cells transplantable to adult recipients can be generated both by in vitro coculture with murine aorta-gonadmesonephros region-derived stromal cells (11) and in vivo transplantation into fetuses or FL (12)(13)(14)(15). These data suggest that further stimulation of embryonic hematopoietic cells by the fetal environment may be critical to step up their potential for adult-type hematopoiesis.…”

Erythropoiesis from acetyl LDL incorporating endothelial cells at the preliver stage

“…Intracardiac inoculations were performed at 10 dpc, a time when definitive hematopoiesis is detected both in the YS and the embryo proper. [1][2][3][4][5][6][17][18][19]21 Despite efforts, attempts to perform inoculation earlier than 10 dpc failed, owing to hemorrhages. Inoculated embryos were cultured up to 10.5 dpc.…”

“…1,2 In addition, in both avian and mouse species, the YS was shown to be able to produce definitive HSCs, including cells of erythroid lineage, at the same time as or even slighly before the AGM formation. [3][4][5][6][7][8] Primitive and definitive erythropoiesis yields mature erythrocytes distinguishable by their morphology and the hemoglobin types they express. Mature primitive erythrocytes are nucleated cells containing embryonic as well as adult hemoglobins, whereas mature definitive erythrocytes are smaller enucleated red blood cells committed to adult hemoglobin synthesis.…”

Primary endothelial cells isolated from the yolk sac and para-aortic splanchnopleura support the expansion of adult marrow stem cells in vitro

“…10 However, coculture of precirculation yolk sac cells with an AGM-derived stromal cell line results in a gain of function of the yolk sac cells that now long-term repopulate lethally irradiated adult recipient mice. 11 A similar gain of function to repopulate adult recipient mice can be obtained by infecting yolk sac cells with a retroviral construct encoding for the transcription factor HoxB4. 12 It remains unclear if the lack of stem cell repopulating ability of the less than 10-dpc yolk sac is due to an absence of cells with this potential or rather to lack of an appropriate environment to support the proliferation or survival of adult repopulating HSCs.…”