Cytokines and sodium induce protein kinase A-dependent cell-surface Na,K-ATPase recruitment via dissociation of NF-kappaB/IkappaB/protein kinase A catalytic subunit complex in collecting duct principal cells.
Collecting duct (CD) principal cells are exposed to large physiologic variations of apical Na+ influx as a result of variations of Na(+) intake and extrarenal losses. It was shown previously that increasing intracellular [Na+] induces recruitment of Na,K-ATPase to the cell surface in a protein kinase A (PKA)-dependent manner in both native and cultured renal CD principal cells. As described previously in response to cytokines in nonrenal cells, PKA activation in response to increased intracellular [Na+] was independent of cAMP and required proteasomal activity. With the use of cultured mpkCCD(cL4) cells as a model of CD principal cells, whether cytokines and increased intracellular [Na+] share a common signaling pathway leading to cell-surface Na,K-ATPase recruitment was investigated. Results showed that two potent inducers of NF-kappaB, LPS and TNF-alpha, enhance Na+ transport and induce cell-surface Na,K-ATPase recruitment in mpkCCD(cL4) cells via cAMP-independent PKA activation. In addition, increased intracellular [Na+] after selective plasma membrane permeabilization by a low concentration of the Na+ ionophore amphotericin B (1 microg/ml) induced dissociation of the PKA catalytic subunit from p65-NF-kappaB and IkappaBalpha. Moreover, inhibitors of NF-kappaB/IkappaB dissociation prevented both Na+-dependent stimulation of PKA activity and cell-surface Na,K-ATPase recruitment. Altogether, these results revealed the presence of a novel Na+-dependent intracellular signaling pathway leading to Na,K-ATPase cell-surface recruitment via dissociation of the PKA catalytic subunit from a macromolecular complex that contains NF-kappaB and IkappaBalpha in CD epithelial cells.
Service of Nephrology, Foundation for Medical Research, Geneva, Switzerland.
Manlio
M
Vinciguerra
Udo
U
Hasler
David
D
Mordasini
Martine
M
Roussel
Maria
M
Capovilla
Eric
E
Ogier-Denis
Alain
A
Vandewalle
Pierre-Yves
PY
Martin
Eric
E
Feraille
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology; D051550:I-kappa B Kinase / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016207:Cytokines; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D012964:Sodium; D051550:I-kappa B Kinase; D017868:Cyclic AMP-Dependent Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase