Human placenta is rich in mesenchymal stem/stromal cells (MSC), with their origin widely presumed fetal. Cultured placental MSCs are confounded by a high frequency of maternal cell contamination. Our recent systematic review concluded that only a small minority of placental MSC publications report fetal/maternal origin, and failed to discern a specific methodology for isolation of fetal MSC fro...

The cellular and molecular mechanisms that regulate the most primitive hematopoietic stem cell are not well understood. We have undertaken a systematic dissection of the complex hematopoietic microenvironment to define some of these mechanisms. An extensive panel of immortalized stromal cell lines from murine fetal liver were established and characterized. Collectively, these cell lines display...

Bone marrow of normal adult mice was found, after transplacental inoculation, to contain cells still able to seed the livers of early fetuses. The recipients' own hematopoietic stem cells, with a W-mutant defect, were at a selective disadvantage. Progression of donor strain cells to the bone marrow, long-term self-renewal, and differentiation into myeloid and lymphoid derivatives was consistent...

The use of hematopoietic stem cells for in utero transplantation to create permanent hematochimerism represents a new concept in fetal therapy, although this approach has provided quite heterogeneous results. Flake and Zanjani have provided an excellent updated review of the current knowledge of in utero stem cell transplantation and have formulated diverse possible reasons for its poor clinica...

Balancing stem cell self-renewal and initiation of lineage specification programs is essential for the development and homeostasis of the hematopoietic system. We have specifically ablated geminin in the developing murine hematopoietic system and observed profound defects in the generation of mature blood cells, leading to embryonic lethality. Hematopoietic stem cells (HSCs) accumulated in the ...

Hepatic progenitor cells play a major role in regenerating diseased liver. In rodents, progenitors forming hepatocytes or cholangiocytes are identified by the stem cell marker Thy-1. The aim of this study was to ascertain whether progenitor cells expressing Thy-1 could be identified in human fetal liver. Midtrimester human fetal liver was immunostained for Thy-1, cytokeratins 18 and 19, vimenti...

  Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organ...

Juvenile myelomonocytic leukemia (JMML) is a rare and aggressive stem cell disease of early childhood. RAS activation constitutes the core component of oncogenic signaling. In addition, leukemic blasts in one-fourth of JMML patients present with monosomy 7, and more than half of patients show elevated age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the cur...

The platelet glycoprotein IIb (alpha(IIb); CD41) constitutes the alpha subunit of a highly expressed platelet surface integrin protein. We demonstrate that CD41 serves as the earliest marker of primitive erythroid progenitor cells in the embryonic day 7 (E7.0) yolk sac and high-level expression identifies essentially all E8.25 yolk sac definitive hematopoietic progenitors. Some definitive hemat...

Self-renewal, replication, and differentiation of hematopoietic stem cells (HSCs) are regulated by cytokines produced by niche cells in fetal liver and bone marrow. HSCs must overcome stresses induced by cytokine deprivation during normal development. In this study, we found that ubiquitin-specific peptidase 10 (USP10) is a crucial deubiquitinase for mouse hematopoiesis. All USP10 knockout (KO)...