title: Regulation of pendrin by cAMP: possible involvement in β-adrenergic-dependent NaCl retention.
abstract: The sodium-independent anion exchanger pendrin is expressed in several tissues including the kidney cortical collecting duct (CCD), where it acts as a chloride/bicarbonate exchanger and has been shown to participate in the regulation of acid-base homeostasis and blood pressure. The renal sympathetic nervous system is known to play a key role in the development of salt-induced hypertension. This study aimed to determine whether pendrin may partly mediate the effects of β adrenergic receptors (β-AR) on renal salt handling. We investigated the regulation of pendrin activity by the cAMP/protein kinase A (PKA) signaling pathway, both in vitro in opossum kidney proximal (OKP) cells stably transfected with pendrin cDNA and ex vivo in isolated microperfused CCDs stimulated by isoproterenol, a β-AR agonist. We found that stimulation of the cAMP/PKA pathway in OKP cells increased the amount of pendrin at the cell surface as well as its transport activity. These effects stemmed from increased exocytosis of pendrin and were associated with its phosphorylation. Furthermore, cAMP effects on the membrane expression and activity of pendrin were abolished by mutating the serine 49 located in the intracellular N-terminal domain of pendrin. Finally, we showed that isoproterenol increases pendrin trafficking to the apical membrane as well as the reabsorption of both Cl(-) and Na(+) in microperfused CCDs. All together, our results strongly suggest that pendrin activation by the cAMP/PKA pathway underlies isoproterenol-induced stimulation of NaCl reabsorption in the kidney collecting duct, a mechanism likely involved in the sodium-retaining effect of β-adrenergic agonists.
authors.affiliation: UPMC Université Paris 06, Université Paris 05, INSERM, UMRS872, and CNRS ERL7226, Laboratoire de Génomique, Physiologie et Physiopathologie Rénales, Centre de Recherche des Cordeliers, Paris, France.
authors.forename: Anie
authors.initials: A
authors.lastname: Azroyan
authors.forename: Luciana
authors.initials: L
authors.lastname: Morla
authors.forename: Gilles
authors.initials: G
authors.lastname: Crambert
authors.forename: Kamel
authors.initials: K
authors.lastname: Laghmani
authors.forename: Sureshkrishna
authors.initials: S
authors.lastname: Ramakrishnan
authors.forename: Aurélie
authors.initials: A
authors.lastname: Edwards
authors.forename: Alain
authors.initials: A
authors.lastname: Doucet
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D027321:Anion Transport Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D027963:Chloride-Bicarbonate Antiporters / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology* / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D007545:Isoproterenol / Q000494:pharmacology; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D023421:Models, Animal; D009893:Opossums; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D012965:Sodium Chloride / Q000378:metabolism*; D000076988:Sulfate Transporters
chemical_list: D000318:Adrenergic beta-Agonists; D027321:Anion Transport Proteins; D027963:Chloride-Bicarbonate Antiporters; D011943:Receptors, Adrenergic, beta; C494615:Slc26A4 protein, rat; C494849:Slc26a4 protein, mouse; D000076988:Sulfate Transporters; D012965:Sodium Chloride; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D007545:Isoproterenol