NADPH oxidase 4 deficiency reduces aquaporin-2 mRNA expression in cultured renal collecting duct principal cells via increased PDE3 and PDE4 activity.
The final control of renal water reabsorption occurs in the collecting duct (CD) and relies on regulated expression of aquaporin-2 (AQP2) in principal CD cells. AQP2 transcription is primarily induced by type 2 vasopressin receptor (V2R)-cAMP-protein kinase A (PKA) signaling but also by other factors, including TonEBP and NF-κB. NAPDH oxidase 4 (NOX4) represents a major source of reactive oxygen species (ROS) in the kidney. Because NOX-derived ROS may alter PKA, TonEBP and NF-κB activity, we examined the effects of NOX4 depletion on AQP2 expression. Depleted NOX4 expression by siRNA (siNOX4) in mpkCCDcl4 cells attenuated increased AQP2 mRNA expression by arginine vasopressin (AVP) but not by hypertonicity, which induces both TonEBP and NF-κB activity. AVP-induced AQP2 expression was similarly decreased by the flavoprotein inhibitor diphenyleneiodonium. siNOX4 altered neither TonEBP nor NF-κB activity but attenuated AVP-inducible cellular cAMP concentration, PKA activity and CREB phosphorylation as well as AQP2 mRNA expression induced by forskolin, a potent activator of adenylate cyclase. The repressive effect of siNOX4 on AVP-induced AQP2 mRNA expression was abolished by the non-selective phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX) and was significantly decreased by selective PDE antagonists cilostamide and rolipram, but not vinpocetine, which respectively target PDE3, PDE4 and PDE1. Thus, by inhibiting PDE3 and PDE4 activity NOX4-derived ROS may contribute to V2R-cAMP-PKA signaling and enhance AQP2 transcription.
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland.
Eric
E
Féraille
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland.
Eva
E
Dizin
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland.
Isabelle
I
Roth
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland.
Jean-Paul
JP
Derouette
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland ; Service of Endocrinology, Diabetology, Hypertension and Nutrition, Department of Medical Specialties, University of Geneva, Geneva, Switzerland.
Ildiko
I
Szanto
Service of Nephrology, Department of Medical Specialties, University of Geneva, Geneva, Switzerland.
Pierre-Yves
PY
Martin
Service of Nephrology, Department of Medical Specialties, University of Geneva, Geneva, Switzerland.
Sophie
S
de Seigneux
Departments of Cellular Physiology and Metabolism, University Medical Center, Geneva, Switzerland.
Udo
U
Hasler
D015056:1-Methyl-3-isobutylxanthine; D000818:Animals; D051399:Aquaporin 2 / Q000235:genetics / Q000378:metabolism*; D001127:Arginine Vasopressin / Q000378:metabolism; D015153:Blotting, Western; D000242:Cyclic AMP / Q000378:metabolism; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3 / Q000378:metabolism*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000166:cytology; D051379:Mice; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000172:deficiency*; D015363:Quinolones; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020889:Rolipram; D015398:Signal Transduction / Q000502:physiology
D051399:Aquaporin 2; D015363:Quinolones; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D001127:Arginine Vasopressin; C021294:cilostamide; D000242:Cyclic AMP; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517289:Pde3a protein, mouse; C095813:Pde4a protein, mouse; D020889:Rolipram; D015056:1-Methyl-3-isobutylxanthine