Nfat5 is involved in the hyperosmotic regulation of Tmem184b, which could be involved in ibuprofen transport in renal MDCK I cells

Purpose: To investigate the involvement of Nfat5 in the regulation of an ibuprofen transporter Method: Reverse transfection with siRNA against Nfat5 was used to knockdown Nfat5 in MDCK I cells. The uptake of both radiolabelled taurine and ibuprofen was measured in MDCK I cells, first treated with siRNA against Nfat5 for 24 h and afterwards cultivated with raffinose-supplemented normal growth medium (500 mOsm) for 24 h. The knock down of NFat5 was investigated by qpCR and western blotting. A transcriptome analysis of MDCK I cells treated with siRNA against Nfat5 was performed. Validation of the transcriptome analysis was perform with qPCR and radiolabelled uptake of ibuprofen. Results: The siRNA transfection resulted in a knock down of Nfat5, and the uptake of both taurine and ibuprofen was significant decreased in the transfected MDCK I cells. The transcriptome analysis of MDCK I cells treated with siRNA against Nfat5 revealed genes regulated by Nfat5 during hyperosmotic exposure. qPCR and the transciptome analysis showed an involvement of Nfat5 in the hyperosmotic regulation of Tmem184 and uptake in Tmem184b-siRNA treated MDCK I cells showed that Tmem184b might be involved in uptake of ibuprofen. Conclusion: The regulation of Tmem184b was found regulated by Nfat5 and could be a potential possible candidate for the gene product responsible for the uptake of ibuprofen in MDCK I cells The transcriptome analysis was performed in duplicate (all other experiments were performed in triplicate or more) with both control for the osmotic treatement, the off-target effect of siRNA, and controls for the reagens