title: Na+/K+-ATPase α1 isoform mediates ouabain-induced expression of cyclin D1 and proliferation of rat sertoli cells.
abstract: Novel roles for the interaction of cardiotonic steroids to Na(+)/K(+)-ATPase have been established in recent years. The aim of this study was to investigate the intracellular signaling events downstream the action of ouabain on Na(+)/K(+)-ATPase in Sertoli cell obtained from immature rats. Treatment of Sertoli cells with ouabain (1 μM) induced a rapid and transient increase in the extracellular signal-regulated kinase (ERK1/2 or MAPK3/1) and phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT) phosphorylation. Also, ouabain upregulated the expression of cyclin D1 and incorporation of [methyl-(3)H]thymidine, both of which were dependent on MAPK3/1 but not AKT intracellular cascade, as shown by pretreatment with MEK (MAP2K1/2) inhibitor U0126 and PI3K inhibitor wortmannin respectively. Moreover, the effect of ouabain on these proliferation parameters was completely prevented by phospho-cAMP response element-binding protein (CREB)/CREB-binding protein complex inhibitor KG501 and only partially by nuclear factor κB nuclear translocation inhibitor SN50. Pretreatment with estrogen receptor antagonist ICI 182780 showed that MAPK3/1 activation by ouabain does not involve this receptor. The Na(+)/K(+)-ATPase α1 isoform, but not α4, was detected in Sertoli cells, suggesting that ouabain effects in Sertoli cells are mediated via α1. Taken together, these results show a rapid ouabain action in the Sertoli cells, which in turn can modulate nuclear transcriptional events essential for Sertoli cell proliferation in a critical period of testicular development. Our findings are important to understand the role of ouabain in the testis and its possible implications in male infertility.
authors.affiliation: Setor de Endocrinologia Experimental, Departamento de Farmacologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, São Paulo, Brazil.
authors.forename: Thaís F G
authors.initials: TF
authors.lastname: Lucas
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Amaral
authors.forename: Catarina S
authors.initials: CS
authors.lastname: Porto
authors.forename: Luis E M
authors.initials: LE
authors.lastname: Quintas
mesh_terms: D000818:Animals; D002301:Cardiac Glycosides / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D019938:Cyclin D1 / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012708:Sertoli Cells / Q000187:drug effects* / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D002301:Cardiac Glycosides; C530106:Ccnd1 protein, rat; D017362:Cyclic AMP Response Element-Binding Protein; D016328:NF-kappa B; D020033:Protein Isoforms; D019938:Cyclin D1; D010042:Ouabain; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; C499075:Atp1a1 protein, rat; D000254:Sodium-Potassium-Exchanging ATPase