Cellular differentiation

About: Cellular differentiation is a research topic. Over the lifetime, 90966 publications have been published within this topic receiving 6099252 citations. The topic is also known as: Cellular differentiation & GO:0030154.

Origin of osteoclasts: mature monocytes and macrophages are capable of differentiating into osteoclasts under a suitable microenvironment prepared by bone marrow-derived stromal cells.

Abstract: We previously reported that osteoclast-like cells were formed in cocultures of a mouse marrow-derived stromal cell line (ST2) with mouse spleen cells in the presence of 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. In this study, we developed a new coculture system to determine the origin of osteoclasts. When relatively small numbers of mononuclear cells (10(3)-10(5) cells per well) obtained from mouse bone marrow, spleen, thymus, or peripheral blood were cultured for 12 days on the ST2 cell layers, they formed colonies with a linear relationship between the number of colonies formed and the number of hemopoietic cells inoculated. Tartrate-resistant acid phosphatase (TRAPase)-positive mononuclear and multinucleated cells appeared in the colonies (TRAPase-positive colonies) in response to 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. When hemopoietic cells suspended in a collagen-gel solution were cultured on the ST2 cell layers to prevent their movement, TRAPase-positive colonies were similarly formed, indicating that each colony originated from a single cell. All of the colonies consisted of nonspecific esterase-positive cells. The monocyte-depleted population prepared from peripheral blood failed to form colonies, whereas the monocyte-enriched population produced a large number of TRAPase-positive colonies. In addition, alveolar macrophages formed TRAPase-positive colonies most efficiently on the ST2 cell layers in the presence of the two hormones. Salmon 125I-labeled calcitonin specifically bound to the TRAPase-positive cells. Resorption lacunae were formed on dentine slices on which cocultures were performed. When direct contact between the peripheral blood cells and the ST2 cells was inhibited by a collagen-gel sheet, no TRAPase-positive cells were formed. These results indicate that osteoclasts are also derived from the mature monocytes and macrophages when a suitable microenvironment is provided by bone marrow-derived stromal cells.

Comparison of proliferative and multilineage differentiation potential of human mesenchymal stem cells derived from umbilical cord and bone marrow.

Abstract: Human umbilical cord perivascular cells (HUCPVCs) have been shown to have a high proliferative potential and the capacity to differentiate into an osteogenic phenotype. HUCPVCs have thus been considered a possible extra-embryonic mesenchymal stem cell (MSC) source for cell-based therapies. To assess this potential, we compared HUCPVCs to the "gold standard" bone marrow mesenchymal stromal cells (BMSCs) with respect to their proliferation, differentiation, and transfection capacities. HUCPVCs showed a higher proliferative potential than BMSCs and were capable of osteogenic, chondrogenic, and adipogenic differentiation. Interestingly, osteogenic differentiation of HUCPVCs proceeded more rapidly than BMSCs. Additionally, HUCPVCs expressed higher levels of CD146, a putative MSC marker, relative to BMSCs. HUCPVCs showed comparable transfection efficiency as BMSCs using a nucleofection method but were more amenable to transfection with liposomal methods (FuGENE). Gene array analysis showed that HUCPVCs also expressed Wnt signaling pathway genes that have been implicated in the regulation of MSCs. The similar characteristics between HUCPVCs and MSCs support the applicability of HUCPVCs for cell-based therapies. Disclosure of potential conflicts of interest is found at the end of this article.

Nuclear Reprogramming of Somatic Cells After Fusion with Human Embryonic Stem Cells

Abstract: We have explored the use of embryonic stem cells as an alternative to oocytes for reprogramming human somatic nuclei. Human embryonic stem (hES) cells were fused with human fibroblasts, resulting in hybrid cells that maintain a stable tetraploid DNA content and have morphology, growth rate, and antigen expression patterns characteristic of hES cells. Differentiation of hybrid cells in vitro and in vivo yielded cell types from each embryonic germ layer. Analysis of genome-wide transcriptional activity, reporter gene activation, allele-specific gene expression, and DNA methylation showed that the somatic genome was reprogrammed to an embryonic state. These results establish that hES cells can reprogram the transcriptional state of somatic nuclei and provide a system for investigating the underlying mechanisms.