Effects of ouabain on proliferation of human endothelial cells correlate with Na+,K+-ATPase activity and intracellular ratio of Na+ and K+
- 78 Downloads
Side-by-side with inhibition of the Na+,K+-ATPase ouabain and other cardiotonic steroids (CTS) can affect cell functions by mechanisms other than regulation of the intracellular Na+ and K+ ratio ([Na+]i/[K+]i). Thus, we compared the doseand time-dependences of the effect of ouabain on intracellular [Na+]i/[K+]i ratio, Na+,K+-ATPase activity, and proliferation of human umbilical vein endothelial cells (HUVEC). Treatment of the cells with 1-3 nM ouabain for 24-72 h decreased the [Na+]i/[K+]i ratio and increased cell proliferation by 20-50%. We discovered that the same ouabain concentrations increased Na+,K+-ATPase activity by 25-30%, as measured by the rate of 86Rb+ influx. Higher ouabain concentrations inhibited Na+,K+-ATPase, increased [Na+]i/[K+]i ratio, suppressed cell growth, and caused cell death. When cells were treated with low ouabain concentrations for 48 or 72 h, a negative correlation between [Na+]i/[K+]i ratio and cell growth activation was observed. In cells treated with high ouabain concentrations for 24 h, the [Na+]i/[K+]i ratio correlated positively with proliferation inhibition. These data demonstrate that inhibition of HUVEC proliferation at high CTS concentrations correlates with dissipation of the Na+ and K+ concentration gradients, whereas cell growth stimulation by low CTS doses results from activation of Na+,K+-ATPase and decrease in the [Na+]i/[K+]i ratio.
Keywordsproliferation endothelium Na+,K+-ATPase ouabain intracellular Na+ and K+
human umbilical vein endothelial cells
immediate early genes
Unable to display preview. Download preview PDF.
- 7.Koltsova, S. V., Trushina, Y., Haloui, M., Akimova, O. A., Tremblay, J., Hamet, P., and Orlov, S. N. (2012) Ubiquitous [Na+]i/[K+]i-sensitive transcriptome in mammalian cells: evidence for Cai 2+-independent excitation–transcription coupling, PLoS One, 7, e38032.CrossRefPubMedPubMedCentralGoogle Scholar
- 15.Klimanova, E. A., Petrushenko, I. Y., Mitkevich, V. A., Anashkina, A. A., Orlov, S. N., Makarov, A. A., and Lopina, O. D. (2015) Binding of ouabain and marinobufagenin leads to different structural changes in Na, K-ATPase and depends on the enzyme conformation, FEBS Lett., 589, 2668–2674.CrossRefPubMedGoogle Scholar
- 17.Orlov, S. N., Thorin-Trescases, N., Pchejetski, D., Taurin, S., Farhat, N., Tremblay, J., Thorin, E., and Hamet, P. (2004) Na+/K+ pump and endothelial cell survival: [Na+]i/[K+]i-independent necrosis triggered by ouabain, and protection against apoptosis mediated by elevation of [Na+]i, Pflugers Arch., 448, 335–345.CrossRefPubMedGoogle Scholar
- 25.Ren, Y. P., Zhang, M. J., Zhang, T., and Huang, R. W. (2014) Dual effects of ouabain on the regulation of proliferation and apoptosis in human umbelical vein endothelial cells: involvement of Na+,K+-ATPase a-subinits and NFκB, Int. J. Clin. Exp. Med., 7, 1244-1222.Google Scholar
- 27.Holthouse, K. A., Mandal, A., Merchant, M. L., Schelling, J. R., Delamere, N. A., Valdes, R. R., Tyagi, S. C., Lederer, E. D., and Khundmiri, S. J. (2010) Ouabain stimulates NaK-ATPase through a sodium/hydrogen exchanger-1 (NHE1)-dependent mechanism in human kidney proximal tubule cells, Am. J. Physiol. Renal Physiol., 299, F77–F90.CrossRefGoogle Scholar
- 32.Khundmiri, S. J., Metzler, M. A., Ameen, M., Amin, V., Rane, M. J., and Delamere, N. A. (2006) Ouabain induces cell proliferation through calcium dependent phosphorylation of Akt (protein kinase B) in opossum kidney proximal tubule cells, Am. J. Physiol. Cell Physiol., 291, C1247–1257.CrossRefPubMedGoogle Scholar
- 35.Pierre, S., Compe, E., Grillasca, J. P., Plannells, R., Sampol, J., Pressley, T. A., and Maixent, J. M. (2001) RPPCR detection of Na,K-ATPase subunit isoforms in human unbilical vein endothelial cells (HUVEC): evidence for the presence of a1 and b3, Cell. Mol. Biol., 47, 319–324.PubMedGoogle Scholar
- 43.Marakhova, I. I., Vereninov, A. A., Toropova, F. V., and Vinogradova, T. A. (1998) Na,K-ATPase pump in activated human lymphocytes: on the mechanisms of rapid and longterm increase in K influxes during the initiation of phytohemagglutinin-induced proliferation, Biochim. Biophys. Acta, 1368, 61–72.CrossRefPubMedGoogle Scholar