A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells.

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells.

Plasminogen activator inhibitor-1 messenger RNA expression is induced in rat hepatocytes in vivo by dexamethasone.

Plasminogen activator inhibitor-1 (PAI-1), the major physiologic inhibitor of tissue plasminogen activator (tPA), plays a crucial role in the regulation of fibrinolysis. Both hepatocytes and endothelial cells have been implicated as major sources of plasma PAI-1. To study the relative contribution of these cell types to hepatic PAI-1 production, we have separated hepatocytes and hepatic sinusoidal endothelial cells by fractionation of freshly isolated rat livers using metrizamide density gradients and centrifugal elutriation.

Homing of a cloned multipotential stem cell line in spleen and intraperitoneal membrane.

B6SUT is a murine cell line cloned from nonadherent cells of viral-infected long-term marrow cultures. In soft agar it can form colonies of three different hemopoietic lineages and is considered to be a hemopoietic stem cell line. We studied its ability to "home" in the spleen of lethally irradiated mice.

Liver endothelium mediates the uptake of iron-transferrin complex by hepatocytes.

We have previously shown that in the liver, transferrin (TF) receptors are limited to endothelial cells, and hepatocytes and Kupffer cells do not have TF receptors. To study the transport of iron into hepatocytes, we fractionated liver cell suspensions into endothelium and hepatocyte fractions. At 4 degrees C liver (but not umbilical cord) endothelium bound Fe-TF with a saturable kinetics.