Telomeres shortening ultimately limits the replicative lifespan of cultured human somatic cells. Telomeres also shorten during replicative aging in vivo in hematopoietic cells, including early hematopoietic progenitors and hematopoietic stem cells (HSC), from humans and mice, despite readily detectable levels of telomerase in these cells. To assess the relevance of telomerase to the long-term r...

The role that NK cells play in the rejection of hemopoietic stem cell (HSC) and tolerance induction has remained controversial. In this study, we examined whether NK cells play a direct role in the rejection of HSC. Purified HSC from MHC class II-deficient mice engrafted readily in congenic mice, while HSC from class I-deficient donors (beta(2)-microglobulin(-/-) (beta(2)m(-/-))) failed to engr...

PURPOSE OF REVIEW All the cells present in the blood are derived from the hematopoietic stem cell (HSC). Because mature blood cells have a limited life span, HSCs must perpetuate themselves through self-renewal to maintain a functional hematopoietic compartment for the lifetime of an organism. This review focuses on studies that identify the Wnt signaling pathway as a mediator of HSC self-renew...

BACKGROUND Hepatic stellate cells (HSC) are important mediators of liver fibrosis. HSC express purinergic receptors for extracellular ATP that induce fibrogenesis. Pyridoxal-phosphate-6-azophenyl-2', 4'-disulfonate (PPADS) is a highly bioavailable purinoceptor inhibitor. We sought to determine whether PPADS could prevent experimental liver fibrosis in rats. MATERIALS AND METHODS The effect of...

BACKGROUND/AIMS In designing a versatile liposomal drug carrier to hepatic stellate cells (HSC), the interaction of mannose 6-phosphate human serum albumin (M6P-HSA) liposomes with cultured cells was studied. METHODS M6P-HSA was covalently coupled to the liposomal surface and the uptake and binding of 3H-labelled M6P-HSA liposomes by primary rat HSC and liver endothelial cells was determined....

One obstacle to retrovirus-mediated gene therapy for human hematopoietic disorders is the low efficiency of gene transfer into pluripotent hematopoietic stem cells (HSC). We have previously shown a direct correlation between retrovirus receptor mRNA levels in mouse HSC and the efficiency with which they are transduced. In the present study, we assayed retrovirus receptor mRNA levels in a variet...

A small number of hematopoietic stem cells (HSCs) with self-renewal and multi-lineage repopulation capacity maintain hematopoiesis during the lifetime of an individual. Moreover, HSCs and their potential exist in excess as one individual can share its HSCs with another leading to creation of a genetically identical hematopoietic system. For over half a century this property of HSCs has been uti...

We previously showed that immature CD166(+) osteoblasts (OB) promote hematopoietic stem cell (HSC) function. Here, we demonstrate that CD166 is a functional HSC marker that identifies both murine and human long-term repopulating cells. Both murine LSKCD48(-)CD166(+)CD150(+) and LSKCD48(-)CD166(+)CD150(+)CD9(+) cells, as well as human Lin(-)CD34(+)CD38(-)CD49f(+)CD166(+) cells sustained signific...

The Wnt system is highly complex and is comprised of canonical and non-canonical pathways leading to the activation of gene expression. Our aim was to examine changes in the expression of Wnt ligands and regulators during hepatic stellate cell (HSC) transdifferentiation and assess the relative contributions of the canonical and non-canonical Wnt pathways in fibrogenic activated HSC. The express...