title: Uroguanylin inhibits H-ATPase activity and surface expression in renal distal tubules by a PKG-dependent pathway.
abstract: Cumulative evidence suggests that guanylin peptides play an important role on electrolyte homeostasis. We have previously reported that uroguanylin (UGN) inhibits bicarbonate reabsorption in a renal distal tubule. In the present study, we tested the hypothesis that the bicarbonaturic effect of UGN is at least in part attributable to inhibition of H(+)-ATPase-mediated hydrogen secretion in the distal nephron. By in vivo stationary microperfusion experiments, we were able to show that UGN inhibits H(+)-ATPase activity by a PKG-dependent pathway because KT5823 (PKG inhibitor) abolished the UGN effect on distal bicarbonate reabsorption and H89 (PKA inhibitor) was unable to prevent it. The in vivo results were confirmed by the in vitro experiments, where we used fluorescence microscopy to measure intracellular pH (pHi) recovery after an acid pulse with NH4Cl. By this technique, we observed that UGN and 8 bromoguanosine-cGMP (8Br-cGMP) inhibited H(+)-ATPase-dependent pHi recovery and that the UGN inhibitory effect was abolished in the presence of the PKG inhibitor. In addition, by using RT-PCR technique, we verified that Madin-Darby canine kidney (MDCK)-C11 cells express guanylate cyclase-C. Besides, UGN stimulated an increase of both cGMP content and PKG activity but was unable to increase the production of cellular cAMP content and PKA activity. Furthermore, we found that UGN reduced cell surface abundance of H+-ATPase B1 subunit in MDCK-C11 and that this effect was abolished by the PKG inhibitor. Taken together, our data suggest that UGN inhibits H(+)-ATPase activity and surface expression in renal distal cells by a cGMP/PKG-dependent pathway.
authors.affiliation: Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil;
authors.forename: Vanessa
authors.initials: V
authors.lastname: da Silva Lima
authors.affiliation: Heart Institute (InCor), and.
authors.forename: Renato O
authors.initials: RO
authors.lastname: Crajoinas
authors.affiliation: Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, São Paulo, Brazil;
authors.forename: Luciene R
authors.initials: LR
authors.lastname: Carraro-Lacroix
authors.affiliation: Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil;
authors.forename: Alana N
authors.initials: AN
authors.lastname: Godinho
authors.affiliation: Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil;
authors.forename: João L G
authors.initials: JL
authors.lastname: Dias
authors.affiliation: Heart Institute (InCor), and.
authors.forename: Rafael
authors.initials: R
authors.lastname: Dariolli
authors.affiliation: Heart Institute (InCor), and.
authors.forename: Adriana C C
authors.initials: AC
authors.lastname: Girardi
authors.affiliation: Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil; Mackenzie University, São Paulo, São Paulo, Brazil.
authors.forename: Manassés C
authors.initials: MC
authors.lastname: Fonteles
authors.affiliation: Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, São Paulo, Brazil;
authors.forename: Gerhard
authors.initials: G
authors.lastname: Malnic
authors.affiliation: Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil; lucilialessa17@gmail.com.
authors.forename: Lucília M A
authors.initials: LM
authors.lastname: Lessa
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D007686:Kidney Tubules, Distal / Q000187:drug effects* / Q000201:enzymology; D061985:Madin Darby Canine Kidney Cells; D008297:Male; D045265:Natriuretic Peptides / Q000494:pharmacology*; D010477:Perfusion; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021381:Protein Transport; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D050705:Receptors, Guanylate Cyclase-Coupled / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D001639:Bicarbonates; D045265:Natriuretic Peptides; D047428:Protein Kinase Inhibitors; C084362:uroguanylin; D017869:Cyclic GMP-Dependent Protein Kinases; D006180:Proton-Translocating ATPases; D050705:Receptors, Guanylate Cyclase-Coupled; D006152:Cyclic GMP
keywords: H+-ATPase; PKG; cGMP; distal tubule; renal microperfusion; uroguanylin