title: Long term regulation of aquaporin-2 expression in vasopressin-responsive renal collecting duct principal cells.
abstract: Fine regulation of water reabsorption by the antidiuretic hormone [8-arginine]vasopressin (AVP) occurs in principal cells of the collecting duct and is largely dependent on regulation of the aquaporin-2 (AQP2) water channel. AVP-inducible long term AQP2 expression was investigated in immortalized mouse cortical collecting duct principal cells. Combined RNase protection assay, Western blot, and immunofluorescence analyses revealed that physiological concentrations of AVP added to the basal side, but not to the apical side, of cells grown on filters induced both AQP2 mRNA and apical protein expression. The stimulatory effect of AVP on AQP2 expression followed a V(2) receptor-dependent pathway because [deamino-8-d-arginine]vasopressin (dDAVP), a specific V(2) receptor agonist, produced the same effect as AVP, whereas the V(2) antagonist SR121463B antagonized action of both AVP and dDAVP. Moreover, forskolin and cyclic 8-bromo-AMP fully reproduced the effects of AVP on AQP2 expression. Analysis of protein degradation pathways showed that inhibition of proteasomal activity prevented synthesis of AVP-inducible AQP2 mRNA and protein. Once synthesized, AQP2 protein was quickly degraded, a process that involves both the proteasomal and lysosomal pathways. This is the first study that delineates induction and degradation mechanisms of AQP2 endogenously expressed by a renal collecting duct principal cell line.
authors.affiliation: Division of Nephrology, Fondation pour Recherches Médicales, 64 Avenue de la Roseraie, CH-1211, Genève 4, Switzerland.
authors.forename: Udo
authors.initials: U
authors.lastname: Hasler
authors.forename: David
authors.initials: D
authors.lastname: Mordasini
authors.forename: Marcelle
authors.initials: M
authors.lastname: Bens
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bianchi
authors.forename: Francoise
authors.initials: F
authors.lastname: Cluzeaud
authors.forename: Martine
authors.initials: M
authors.lastname: Rousselot
authors.forename: Alain
authors.initials: A
authors.lastname: Vandewalle
authors.forename: Eric
authors.initials: E
authors.lastname: Feraille
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Martin
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000378:metabolism; D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism; D013997:Time Factors; D014667:Vasopressins / Q000378:metabolism*
chemical_list: C496024:Aqp2 protein, mouse; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D009097:Multienzyme Complexes; D019384:Nucleic Acid Synthesis Inhibitors; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D014667:Vasopressins; C067713:lactacystin; D003609:Dactinomycin; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D012260:Ribonucleases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D003894:Deamino Arginine Vasopressin; D000111:Acetylcysteine