BRAIN-DERIVED PEPTIDES INCREASE THE EXPRESSION OF A BLOOD-BRAIN-BARRIER GLUT1 GLUCOSE-TRANSPORTER REPORTER GENE

The brain-derived peptide preparation Cerebrolysin (Cl; EBEWE, Austria ) increases the stability of blood-brain barrier (BBB)-GLUT1 transcrip t. To determine if the increase in BBB-GLUT1 mRNA stability is associa ted with an augmentation of gene expression, the present investigation studied the effect of Cl on the expression of a BBB-GLUT1-luciferase reporter gene in brain endothelial cultured (ECL) cells. Dose response studies showed that Cl markedly increased the expression of luciferas e when the BBB-GLUT1-reporter gene was used. On the contrary, Cl produ ced no changes in the expression pattern of the control reporter gene, which lacks the GLUT1 regulatory sequence. Desensitization of the pro tein kinase C (PKC) receptor with the phorbol ester TPA, or inhibition with either 1-(5-isoquinolinylsuIfonyl)-2-methylpiperazine (H7) or st aurosporine, had no effect on the increased levels of luciferase induc ed by Cl. Transfection efficiency was determined by measuring intracel lular levels of the expression vector using a quantitative polymerase chain reaction (PCR) assay. The data presented here demonstrate that C l increases BBB-GLUT1 gene expression in ECL cells through a mechanism that appears to be independent of activation of PKC. Copyright (C) 19 96 Elsevier Science Ireland Ltd.