Purpose: Since its inception the hCEMC/D3 cell line has shown to be a promising in vitro model reflecting some of the in vivo situations at the blood-brain barrier (BBB). This study was conducted to establish and compared the gene and protein expression patterns of 15 cerebral microvascular markers, 11 solute carrier transporters, 10 ABC transporters, MAOs, 10 CYPs, reductase, 16 phase II conjugation enzymes, and 3 transcriptional factors in an in vitro model of the human BBB.
Methods: Using qRT-PCR, expression was determined in hCMEC/D3 cells cultured on plastic flasks, Transwell® inserts treated and untreated with 10mM LiCl and in HUVEC cells.
Results: Claudin-1 was detected in hCMEC/D3 cells only. Brain endothelial cells were about 70-fold less fenestrated than HUVEC cells as indicated by PLVAP. SLC2A1/GLUT1 was impoverished in HUVEC as compared to hCMEC/D3 cells. LiCl treatment enriched the negative Wnt regulator marker Axin2, Claudin-3, Claudin-5, JAM-A and VE-Cadherin in hCEMC/D3 cells. The important ABCB1/MDR1 and ABCG2/BCRP transporters expressed at the BBB were enriched in hCMEC/D3 cells treated with LiCl. Similar to BBB, hCEMC/D3 cells expressed CYP1B1, CYP2U1, MAOA, TPMT, HNMT, COMT and GSTs. Interestingly, LiCl treatment enhanced GSTP1 expression.
Conclusions: Taken together, our results indicate that brain and peripheral microvascular endothelia are different in terms of markers, transporters and metabolizing enzymes. Mimicking in vivo BBB phenotype can be enhanced by improving culture conditions of hCEMC/D3 cells.