Regulation and role of water channel protein, aquaporin in the brain

In the BAS8.1 astroglioma cell lines, TTF-1 transactivated the AQP-1 promoter in a dose-dependent manner. Electrophoretic mobility shift assays showed that TTF-1 binds to specific subsets of its consensus DNA binding sites in the AQP-1 promoter. Assays using cells treated with a high concentration of different solutes revealed a decrease in luciferase activities both of the TTF-1 and AQP-1 promoters. Inhibition of TTF-1 synthesis by antisense oligodeoxynucleotide (ODN) injection decreases AQP-1 synthesis and leads to a decrease in CSF formation. These data suggest that TTF-1 plays an important regulatory role in the transcription of AQP-1, which may be important for formation of cerebrospinal fluid.