Abstract
Thapsigargin has been shown the elevate intracellular Na+ concentration in human lymphocytes, but mechanisms underlying thapsigargin-induced Na+ entry are little understood. In the present study we investigated thapsigargin-induced changes in cytosolic free Na+ and Ca2+ concentration in human lymphocytes after inhibition of the Na+/Ca2+ exchange with two structurally unrelated compounds, dimethylthiourea ad bepridil. The intracellular Na+ increase induced by 5 µM thapsigargin was significantly enhanced in the presence of 5 mM dimethylthiourea or 40 µM bepridil. In contrast, both compounds significantly decreased the thapsigargin-induced intracellular Ca2+ elevation. No effect of dimethylthiourea or bepridil on thapsigargin-induced Ca2+ influx was observed in the absence of extracellular Na+. These observations are consistent with the hypothesis that thapsigargin stimulates Na+/Ca2+ exchange in human lymphocytes. However, Na+/Ca2+ exchange does not mediate Na+ influx in human lymphocytes.
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References
Thastrup O. Role of Ca2+-ATP-ase in regulation of cellular signaling as studied with the selective microsomal Ca2+-ATPase inhibitor, thapsigargin. Agents Actions 1990; 26: 207.
Takemura H, Hughes AR, Thastrup O, Putney JW Jr. Activation of calcium entry by the tumor promoter thapsigargin in parotid acinar cells. Evidence that an intracellular calcium pool and not inositol phosphate regulates calcium fluxes at the plasma membrane. J Biol Chem 1989; 264: 12256.
Demaurex N, Lew DP, Krause KH. Cyclopiazonic acid depletes intracellular Ca2+ stores and activates an influx pathway for divalent cations in HL-60 cells. J Biol Chem 1992; 267: 2318.
Putney JW Jr, Bird GS. The signal for capacitative calcium entry. Cell 1993; 75: 199.
Xu X, Star RA, Tortorici G, Muallem S. Depletion of intracellular Ca2+ stores activates an influx pathway for divalent cations in HL-60 cells. J Biol Chem 1994; 269: 12645
Alvarez J, Montero M, Garcia-Sancho J. Cytochrome P 450 may regulate plasma membrane Ca2+ permeability according to the filling state of the intracellular stores. FASEB J 1992; 6: 786.
Randiamapitha C, Tsien R. Emptying of intracellular Ca2+ stores releases a novell small messenger that stimulates Ca2+ influx. Nature 1993; 364. 809.
Ishikawa S, Fujisawa G, Okada K, Saito T. Thapsigargin increases cellular free calcium and intracellular sodium concentrations in cultured rat glomerular mesangial cells. Biochem Biophys Res Commun 1993; 194: 287.
Tepel M, Kühnapfel SD, Theilmeier G, Teupe C; Schlotmann R, Zidek W. Filling state of intracellular Ca2+ pools triggers trans plasma membrane Na+ and Ca2+ influx by a tyrosine kinase-dependent pathway. J Biol Chem 1994; 269: 26239.
Tepel M, Wischniowski H, Zidek W. Thapsigargin-induced [Ca2+]i increase activates sodium influx in human platelets. Biochem Biophys Acta 1994; 1220: 248.
Wacholtz MC, Cragoe EJ Jr, Lipsky PE. A Na+-dependent Ca2+ exchanger generates the sustained increase in intracellular Ca2+ required for T cell activation. J Immunol 1992; 149: 1912.
Wacholtz Mc, Cragoe EJ Jr, Lipsky PE. Delineation of the role of Na+/Ca2+ exchanger in regulating intracellular Ca2+ in T cells. Cell Immunol 1993; 147: 95.
Ueda T. Na+/Ca2+ exchange activity in rabbit lymphocyte membranes. Biochim Biophys Acta 1983; 734: 342.
Rengasemy A, Saura S, Feinberg H. Platelet Ca2+ homeostsis: Na+/Ca2+ in plasma membrane vesicles. Thromb Haemost 1987; 57: 337.
Simchowitz L, Cragoe EJ Jr. Na+-Ca2+ exchange in human neutrophils. Am J Physiol 1988; 254: C150.
Balasubramanyam M, Kimura M, Aviv P, Gardner JP. Kinetics of Ca2+ transport across the lymphocyte plasma membrane. Am J Physiol 1993; 265: C321.
Herchulez A, Lebrun P. A role for Na/Ca exchanger in the pancreatic B cell. Studies with thapsigargin and caffeine. Biochem Pharmacol 1993; 45: 7.
Chernaya G, Vazquez M, Reeves JP. Sodium-calcium exchange and store-dependent calcium influx in transfected chinese hamster ovary cells expressing the bovine cardiac sodium-calcium exchanger. Acceleration of exchange activity in thapsigargin-treated cells. J Biol Chem 1996; 8: 5378.
Balasubramanyam M, Rohowsky-Kochan C, Reeves JP, Gardner JP. Na+/Ca2+ exchange-mediated calcium entry in human lymphocytes. J Clin Invest 1994; 94: 2002.
Battle DC, Godinich M, Lapointe MS, Munoz E, Carone M, Mehring N. Extracellular Na+ dependency of cytosolic Ca2+ regulation in aortic vascular smooth muscle cells. Am J Physiol 1991; 261: C845.
Ziegelstein RC, Zweier JL, Mellits ED, Younes A, Lakatta EG, Stern MD, Silverman HS. Dimethylthiourea, an oxygen radical scavenger, protects isolated cardiac myocytes from hypoxic injury by inhibition of Na+-Ca2+ exchange and not by its antioxidant effect. Circ Res 1992; 70: 804.
Zhu ZZ, Tepel M, Neusser M, Zidek W. Role of Na+-Ca2+ exchange in agonist-induced changes in cytosolic Ca2+ in vascular smooth muscle cells. Am J Physiol 1994; 266: C794.
Liu KQ, Bunnell SC, Gurniak CB, Berg LJ. T cell receptor-initiated calcium release is uncoupled from capacitative calcium entry in Itk-deficient T cells. J Exp Med 1998; 187: 1721.
Esser MT, Haverstick DM, Fuller CL, Gullo CA, Braciale VL. Ca2+ signaling modulates T lymphocyte effector functions. J Exp Med 1998; 187: 1057.
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Nofer, J.R., Pulawski, E., Junker, R. et al. Na+/Ca2+ exchange inhibitors modulate thapsigargin-induced Ca2+ and Na+ influx in human lymphocytes. Int J Clin Lab Res 29, 89–92 (1999). https://doi.org/10.1007/s005990050070
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DOI: https://doi.org/10.1007/s005990050070