Dexamethasone Enhances Vasopressin-Induced Aquaporin-2 Gene Expression in the mpkCCD Cells.

Dexamethasone Enhances Vasopressin-Induced Aquaporin-2 Gene Expression in the mpkCCD Cells. Am J Physiol Renal Physiol. 2017 Oct 25;:ajprenal.00218.2017 Authors: Kuo KT, Yang CW, Yu MJ Abstract The cortical collecting duct cell (mpkCCD) has been an instrumental cell model for studying vasopressin-mediated aquaporin-2 regulation. This cell line was first developed by the Vandewalle's group from a transgenic mouse carrying the transforming SV40 antigens driven by the pyruvate kinase promoter. To immortalize the cells, four hormone supplements (dexamethasone, epidermal growth factor, insulin and triiodothyronine) were used to enhance SV40 antigen expression; however, these hormones appear to have various effects on aquaporin-2 gene expression in the cells. Here, we evaluated the effects of each hormone supplement and found that dexamethasone enhanced vasopressin-induced aquaporin-2 gene expression at both mRNA and protein levels in a dose- and time-dependent manner, without affecting mRNA or protein stability. The effects of dexamethasone were attributed largely to enhanced aquaporin-2 mRNA transcription in association with an enhanced aquaporin-2 promoter activity. Dexamethasone did not affect vasopressin-regulated aquaporin-2 phosphorylation and trafficking. In summary, we optimized the conditions to enhance vasopressin-induced endogenous aquaporin-2 gene expression in the mpkCCD cells. By increasing the amount of aquaporin-2 protein ...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research