The precise time of appearance of the first hematopoietic stem cell activity in the developing mouse embryo is unknown. Recently the aorta-gonad-mesonephros region of the developing mouse embryo has been shown to possess hematopoietic colony-forming activity (CFU-S) in irradiated recipient mice. To determine whether the mouse embryo possesses definitive hematopoietic stem cell activity in the a...

We previously reported that long-lasting in vitro hematopoiesis could be achieved using the cells differentiated from primate embryonic stem (ES) cells. Thus, we speculated that hematopoietic stem cells differentiated from ES cells could sustain long-lasting in vitro hematopoiesis. To test this hypothesis, we investigated whether human hematopoietic stem cells could similarly sustain long-lasti...

BACKGROUND The transcriptional regulation of stem cell genes is still poorly understood. Kit, encoding the stem cell factor receptor, is a pivotal molecule for multiple types of stem/progenitor cells. We previously generated mouse lines expressing transgenic green fluorescent protein under the control of Kit promoter/first intron regulatory elements, and we demonstrated expression in hematopoie...

Hematopoietic stem cells are capable of extensive self-renewal and expansion, particularly during embryonic growth. Although the molecular mechanisms involved with stem cell maintenance remain mysterious, it is now clear that an intraembryonic location, the aorta-gonad-mesonephros (AGM) region, is a site of residence and, potentially, amplification of the definitive hematopoietic stem cells tha...

background: myeloablative-allogeneic stem cell transplantation is a common way of treating various malignant and nonma-lignant diseases; but, it is associated with hazardous immediate and late complications. the majority of patients are not good candidates for high dose therapy because of old age, medical co-morbidities or previous heavy treatments. the donor stem cells can engraft in the recip...

The adult hematopoietic system of mammals is a dynamic hierarchy of cells with the hematopoietic stem cell at its foundation. During embryonic development, the source and expansion potential of this cell remain unclear. Two sites of hematopoietic activity, the yolk sac and aorta-gonad-mesonephros (AGM) region, function in mouse ontogeny at the pre-liver stage of hematopoiesis. However, cellular...

the complexity of multiple sclerosis (ms) and the incompetence of a large number of promise treatments in ms urge us to plan new and more effective therapeutic approaches that aim to suppress ongoing autoimmune responses and induction of local endogenous regeneration. emerging data propose that hematopoietic, mesenchymal and neural stem cells have the potential to restore self-tolerance, to pro...

background: stem cell differentiation is a process composed of vast variety of factors which are controlled by a network of certain mechanisms. this study aims to determine the possible role of dna methylation, a potent regulator of vhl, ecad and runx3 genes during erythroid differentiation driven by mir-451. materials and methods: to determine the methylation status of promoters and the expres...

BACKGROUND The study of adult stem cells relies on the ability to isolate them using complex combinations of markers for flow cytometry. A recent study has used a tetracycline-regulatable H2B-GFP transgenic mouse model analogous to BrdU pulse-chase methods to fluorescently label quiescent skin stem cells in vivo. In this study, we sought to use these mice to fluorescently label hematopoietic st...

Hematopoietic reconstitution after stem cell transplantation requires excessive replicative activity because of the limited number of stem cells that are used for transplantation. Telomere shortening has been detected in hematopoietic cells after bone marrow transplantation. This has been thought to result from excessive replication of the stem cells, with putative concomitant reduction of thei...