Dexamethasone enhances vasopressin-induced aquaporin-2 gene expression in the mpkCCD cells

Kuang-Ting Kuo, Chan-Wei Yang, Ming-Jiun Yu
2018 AJP - Renal Physiology  
Kuo KT, Yang CW, Yu MJ. Dexamethasone enhances vasopressin-induced aquaporin-2 gene expression in the mpkCCD cells. The mouse 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 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
more » ... asone, 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 in the cells, our method will facilitate the study of aquaporin-2 cell physiology regulated by vasopressin.
doi:10.1152/ajprenal.00218.2017 pmid:29070569 fatcat:zglsq4pgwfbspbadjrqh77gycq