Gene transfer to the central nervous system by transplantation of cerebral endothelial cells.

A cerebral endothelial immortalized cell line was used in transplantation experiments to deliver gene products to the adult rat brain. Survival of grafted cells was observed for at least 1 year, without any sign of tumor formation. When genetically modified to express bacterial beta-galactosidase and transplanted into the striatum, these cells were shown, by light and electron microscope analysis, to integrate into the host brain parenchyma and microvasculature.

Nitric oxide and endothelin secretion by brain microvessel endothelial cells: regulation by cyclic nucleotides.

Endothelin (ET)-1 was originally characterized as a potent vasoconstrictor peptide secreted by vascular endothelial cells. It possesses a wide range of biological activities within the cardiovascular system and in other organs, including the brain. Also secreted by endothelial cells, nitric oxide (NO), has recently been identified as a relaxing factor, as well as a pleiotropic mediator, second messenger, immune defence molecule, and neurotransmitter.

Endothelins stimulate c-fos and nerve growth factor expression in astrocytes and astrocytoma.

Endothelin receptors have been identified on astrocytes and astrocytoma, but their physiological significance has remained elusive. It is shown here that endothelins induce c-fos in primary cultures of mouse embryo astrocytes, as well as in two subclones of rat astrocytoma C6 cells, although with different kinetics. In addition, nerve growth factor expression is stimulated, as seen by mRNA accumulation and protein secretion, in primary astrocytes and one of the two C6 subclones, with an apparent correlation with the transience of c-fos induction.

cAMP-dependent down-regulation of endothelin-1 receptors on rat astrocytoma C6 cells.

The density of endothelin-1 (ET-1) receptors on rat astrocytoma C6 cells is down-regulated by activation of protein kinase C (PKC). We have investigated whether intracellular accumulation of cyclic adenosine monophosphate (cAMP) may also modulate surface ET-1 receptor number. The density of ET-1 receptors was measured by binding of [125I]ET-1 on rat astrocytoma C6 intact cells exposed to catecholamines, dibutyryl-cAMP or forskolin.

Immortalization of brain capillary endothelial cells with maintenance of structural characteristics of the blood-brain barrier endothelium.

Early passage bovine brain capillary endothelial cells were immortalized by transfection with the plasmid pSV3 neo. Cells from one clone, SV-BEC, expressed nuclear SV 40 large T antigen, displayed a contact-inhibited and anchorage-dependent proliferation, and a high sensitivity to the addition of exogenous basic fibroblast growth factor. SV-BEC cells are morphologically unaltered and express typical markers of endothelial cells: Factor VIII-related antigen, angiotensin-converting enzyme and Griffonia simplicifolia agglutinin binding site.