ECGF AND HEPARIN DETERMINE DIFFERENTIATION OF CLONED CEREBRAL ENDOTHELIAL-CELLS IN-VITRO

Protein expression patterns of morphologically different cloned capill ary endothelial cells from porcine and murine brain cortices were exam ined. Type I cells, grown in medium containing heparin and endothelial cell growth factor (ECGF), exhibited a polygonal, cobblestone appeara nce and appeared to replicate the cells of the blood-brain barrier end othelium. Type II cells, grown in medium without heparin and ECGF, wer e elongated and appeared to replicate capillaries in central nervous s ystem tissue. Cells of both phenotypes stained positive by the specifi c endothelial cell marker Bandeiraea simplicifolia lectin. The express ion of alpha smooth-muscle actin (mRNA and protein) was taken as a mar ker for type II cells. By use of 2-D gel images and the GELLAB II syst em, a data base was created revealing that two proteins (90 kDa, pI 5. 1, and 35 kDa, pI 5.7) were exclusively expressed in type I cells. Fur thermore, the synergistic action of ECGF and heparin in respect to the phenotypic determination of cerebral endothelial cells was demonstrat ed.