Overexpression of Na+/K+-ATPase parallels the increase in sodium transport and potassium recycling in an in vitro model of proximal tubule cellular ageing

• Tipo: Artigo em Revista Científica Internacional
• Data: 2006

Autores

Silva, E (Autor) Outra; Pedro Gomes (Autor) Outra; soares-da-silva, p (Autor) FMUP

Revista

Título: Journal of Membrane Biology

Vol. 212

Páginas: 163-175

ISSN: 0022-2631

Editora: Springer Nature

Indexação

ISI Web of Knowledge - 17 Citações

Scopus - 17 Citações

Outras Informações

ID Authenticus: P-004-GC7

DOI: 10.1007/s00232-005-7017-5

Abstract (EN): Na+/K+-ATPase plays a key role in the transport of Na+ throughout the nephron, but ageing appears to be accompanied by changes in the regulation and localization of the pump. In the present study, we examined the effect of in vitro cell ageing on the transport of Na+ and K+ ions in opossum kidney (OK) cells in culture. Cells were aged by repeated passing, and Na+/K+-ATPase activity and K+ conductance were evaluated using electrophysiological methods. Na+K+-ATPase alpha(1)- and beta(1)-subunit expression was quantified by Western blot techniques. Na+/H+ exchanger activity, changes in membrane potential, cell viability, hydrogen peroxide production and cellular proliferation were determined using fluorimetric assays. In vitro cell ageing is accompanied by an increase in transepithelial Na+ transport, which results from an increase in the number of Na+/K+-ATPase alpha(1)- and beta(1)-subunits, in the membrane. Increases in Na+/K+-ATPase activity were accompanied by increases in K+ conductance as a result of functional coupling between Na+/K+-ATPase and basolateral K+ channels. Cell depolarization induced by both KCl and ouabain was more pronounced in aged cells. No changes in Na+/H+ exchanger activity were observed. H2O2 production was increased in aged cells, but exposure for 5 days to 1 and 10 mu M of H2O2 had no effect on Na+/K+-ATPase expression. Ouabain (100 nM) increased alpha(1)-subunit, but not beta(1)-subunit, Na+/K+-ATPase expression in aged cells only. These cells constitute an interesting model for the study of renal epithelial cell ageing.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 13