Histogenesis

About: Histogenesis is a research topic. Over the lifetime, 1769 publications have been published within this topic receiving 63283 citations. The topic is also known as: tissue development & GO:0009888.

Efficient differentiation of human embryonic stem cells to definitive endoderm.

Abstract: The potential of human embryonic stem (hES) cells to differentiate into cell types of a variety of organs has generated much excitement over the possible use of hES cells in therapeutic applications. Of great interest are organs derived from definitive endoderm, such as the pancreas. We have focused on directing hES cells to the definitive endoderm lineage as this step is a prerequisite for efficient differentiation to mature endoderm derivatives. Differentiation of hES cells in the presence of activin A and low serum produced cultures consisting of up to 80% definitive endoderm cells. This population was further enriched to near homogeneity using the cell-surface receptor CXCR4. The process of definitive endoderm formation in differentiating hES cell cultures includes an apparent epithelial-to-mesenchymal transition and a dynamic gene expression profile that are reminiscent of vertebrate gastrulation. These findings may facilitate the use of hES cells for therapeutic purposes and as in vitro models of development.

Autoradiographic study of cell migration during histogenesis of cerebral cortex in the mouse.

Abstract: AUTORADIOGRAPHY with thymidine labelled with tritium has proved useful for the study of histogenesis in the mammalian brain1–6. Labelled thymidine injected into animals becomes incorporated almost exclusively into deoxyribonucleic acid of cells preparing to divide and remains in their nuclei as a permanent label; the radioactivity is diluted to half with each cell division7. When the autoradiographic method is applied to tissues of animals killed serially, one can determine the time and place of origin of cells, their route and rate of migration, and their ultimate fate.

Gastric stromal tumors. Reappraisal of histogenesis.

Abstract: Twenty-eight gastric wall tumors classified by light microscopy as leiomyomas or leiomyosarcomas were reevaluated for histogenesis. Each case was analyzed for the presence of S-100 protein, a marker for cells derived from neuroectoderm, by the immunoperoxidase technique. Eight tumors contained cells with positive immunostaining for S-100 protein. Usually this staining was focal, but in one case staining was diffuse. In three additional cases the immunostaining outlined a nerve within the tumor. In contrast, two esophageal and 10 uterine leiomyomas, as well as normal gastric smooth muscle, gave negative reactions for S-100 protein. Twelve cases had tissue processed for electron microscopy. Only two of the tumors, one leiomyoma and one leiomyosarcoma, contained cytoplasmic myofilaments with densities expected in cells derived from smooth muscle; neither of these tumors stained for S-100 protein. In one case, the tumor with diffuse staining for S-100 protein, the cells resembled Schwann cells ultrastructurally. The remaining nine cases had neither smooth muscle nor Schwann cell features. They did contain interposed cell processes, primitive junctions, and large cytoplasmic vacuoles. The results of this study indicate that many gastric wall tumors are not derived from smooth muscle. The presence of S-100 protein suggests a nerve sheath origin in some cases. While the ultrastructure of many gastric tumors does not resemble nerve sheath cells in most peripheral nerves, the myenteric nervous system is a possible source for perineurial or mesenchymal nerve sheath cells with distinctive fine structure. Further study is needed to refine our knowledge of the histogenesis of gastric stromal tumors.

Development of definitive endoderm from embryonic stem cells in culture

Abstract: The cellular and molecular events regulating the induction and tissue-specific differentiation of endoderm are central to our understanding of the development and function of many organ systems. To define and characterize key components in this process, we have investigated the potential of embryonic stem (ES) cells to generate endoderm following their differentiation to embryoid bodies (EBs) in culture. We found that endoderm can be induced in EBs, either by limited exposure to serum or by culturing in the presence of activin A (activin) under serum-free conditions. By using an ES cell line with the green fluorescent protein (GFP) cDNA targeted to the brachyury locus, we demonstrate that endoderm develops from a brachyury(+) population that also displays mesoderm potential. Transplantation of cells generated from activin-induced brachyury(+) cells to the kidney capsule of recipient mice resulted in the development of endoderm-derived structures. These findings demonstrate that ES cells can generate endoderm in culture and, as such, establish this differentiation system as a unique murine model for studying the development and specification of this germ layer.

Initiation of Mammalian Liver Development from Endoderm by Fibroblast Growth Factors

Abstract: The signaling molecules that elicit embryonic induction of the liver from the mammalian gut endoderm or induction of other gut-derived organs are unknown. Close proximity of cardiac mesoderm, which expresses fibroblast growth factors (FGFs) 1, 2, and 8, causes the foregut endoderm to develop into the liver. Treatment of isolated foregut endoderm from mouse embryos with FGF1 or FGF2, but not FGF8, was sufficient to replace cardiac mesoderm as an inducer of the liver gene expression program, the latter being the first step of hepatogenesis. The hepatogenic response was restricted to endoderm tissue, which selectively coexpresses FGF receptors 1 and 4. Further studies with FGFs and their specific inhibitors showed that FGF8 contributes to the morphogenetic outgrowth of the hepatic endoderm. Thus, different FGF signals appear to initiate distinct phases of liver development during mammalian organogenesis.