title: Vasopressin-independent targeting of aquaporin-2 by selective E-prostanoid receptor agonists alleviates nephrogenic diabetes insipidus.
abstract: In the kidney, the actions of vasopressin on its type-2 receptor (V2R) induce increased water reabsorption alongside polyphosphorylation and membrane targeting of the water channel aquaporin-2 (AQP2). Loss-of-function mutations in the V2R cause X-linked nephrogenic diabetes insipidus. Treatment of this condition would require bypassing the V2R to increase AQP2 membrane targeting, but currently no specific pharmacological therapy is available. The present study examined specific E-prostanoid receptors for this purpose. In vitro, prostaglandin E2 (PGE2) and selective agonists for the E-prostanoid receptors EP2 (butaprost) or EP4 (CAY10580) all increased trafficking and ser-264 phosphorylation of AQP2 in Madin-Darby canine kidney cells. Only PGE2 and butaprost increased cAMP and ser-269 phosphorylation of AQP2. Ex vivo, PGE2, butaprost, or CAY10580 increased AQP2 phosphorylation in isolated cortical tubules, whereas PGE2 and butaprost selectively increased AQP2 membrane accumulation in kidney slices. In vivo, a V2R antagonist caused a severe urinary concentrating defect in rats, which was greatly alleviated by treatment with butaprost. In conclusion, EP2 and EP4 agonists increase AQP2 phosphorylation and trafficking, likely through different signaling pathways. Furthermore, EP2 selective agonists can partially compensate for a nonfunctional V2R, providing a rationale for new treatment strategies for hereditary nephrogenic diabetes insipidus.
authors.affiliation: Department of Biomedicine, Water and Salt Research Center, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Emma T B
authors.initials: ET
authors.lastname: Olesen
authors.forename: Michael R
authors.initials: MR
authors.lastname: Rützler
authors.forename: Hanne B
authors.initials: HB
authors.lastname: Moeller
authors.forename: Helle A
authors.initials: HA
authors.lastname: Praetorius
authors.forename: Robert A
authors.initials: RA
authors.lastname: Fenton
mesh_terms: D000527:Alprostadil / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D051399:Aquaporin 2 / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D018500:Diabetes Insipidus, Nephrogenic / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control; D015232:Dinoprostone / Q000031:analogs & derivatives / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D015151:Immunoblotting; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D058307:Receptors, Prostaglandin E, EP2 Subtype / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D017483:Receptors, Vasopressin / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014667:Vasopressins / Q000378:metabolism / Q000494:pharmacology
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D051399:Aquaporin 2; C561931:CAY 10580; D011760:Pyrrolidinones; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D017483:Receptors, Vasopressin; D014667:Vasopressins; D000242:Cyclic AMP; D000527:Alprostadil; C048491:butaprost; D015232:Dinoprostone