Abstract: FR-OR131
Identification of miRNAs Regulating the Water Transport in the Collecting Duct
Session Information
- Urinary Concentration and Acidification
November 03, 2017 | Location: Room 290, Morial Convention Center
Abstract Time: 05:42 PM - 05:54 PM
Category: Fluid, Electrolytes, and Acid-Base
- 702 Water/Urea/Vasopressin, Organic Solutes
Authors
- Petrillo, Federica, University of Campania Luigi Vanvitelli, Napoli, Italy
- Iervolino, Anna, Biogem scarl, Ariano Irpino, Italy
- De Falco, Alfonso, Laboratoire National de Santè, Dudelange, Luxembourg
- Prosperi, Federica, Biogem scarl, Ariano Irpino, Italy
- De la motte, Luigi Regenburgh, University of Campania Luigi Vanvitelli, Napoli, Italy
- Jelen, Sabina K., Biogem S.C.R.L, Ariano Irpino, Italy
- Fenton, Robert A., University of Aarhus, Aarhus, Denmark
- Capasso, Giovambattista, University of Campania Luigi Vanvitelli, Napoli, Italy
- Trepiccione, Francesco, University of Campania, Naples, Italy
Background
Principal cells (PC) contribute to water reabsorption in the collecting duct (CD). In response to vasopressin, they express on their apical membrane the AQP2, and so increase water permeability of the CD. Finally, an interstitium driven osmotic gradient leads the water to be reabsorbed. Although several molecular mechanisms have been identified as master regulators of this process, both dependent and independent by vasopressin stimulation, no miRNAs involved in the water reabsorption are known.
miRNas are post-trascriptional regulators of gene expression and, thus, they are appealing targets for new therapy. We aim to identify the miRNAs involved in urinary concentrating mechanism to fill this gap.
Methods
To identify whether the miRNAs are crucial for the water reabsorption in the CD, we generate a mouse model deficient of dicer selectively in the AQP2 expressing cells. By microarray analysis we compared the miRNAs expressing profile of the inner medulla from Dicer cKO and their littermate control mice. miRNAs target prediction and IPA analysis was used to build a network of interaction between miRNAs and target proteins and to select candidate miRNAs, master regulators of the AQP2 expression. In vitro assay of miRNAs activity has been performed to validate bio-informatic data.
Results
Single segment evaluation of Dicer expression confirmed its ablation only in the CD. Dicer-AQP2 cKO mice present with a severe water concentrating defect that is resistant to dDAVP administration. Loss of expression of AQP2 all along the PC made these mice consistent with an experimental model of neprhogenic diabetes insipidus. Since principal cells keep expressing other cellular markers such as AQP4 and ENaC, our hypothesis was that Dicer suppression targets mostly AQP2 expression. Microarray screening of the miRNas profile reveals potential candidate miRNA, able to directly interfere with the V2R-AQP2 axis. In vitro validation in mpkCCD cells confirms the role of 3 miRNAs in regulating the expression of target mRNA crucial for the water reabsorption.
Conclusion
We identify for the first time miRNAs able to regulate the AQP2 expression in the PC. This is the first step to build a miRNA-based therpy to potentially approach the nephrogenic diabetes insipidus.