The Depletion of Nuclear Glutathione Impairs Cell Proliferation in 3t3 Fibroblasts

Abstract

BackgroundGlutathione is considered essential for survival in mammalian cells and yeast but not in prokaryotic cells. The presence of a nuclear pool of glutathione has been demonstrated but its role in cellular proliferation and differentiation is still a matter of debate.Principal FindingsWe have studied proliferation of 3T3 fibroblasts for a period of 5 days. Cells were treated with two well known depleting agents, diethyl maleate (DEM) and buthionine sulfoximine (BSO), and the cellular and nuclear glutathione levels were assessed by analytical and confocal microscopic techniques, respectively. Both agents decreased total cellular glutathione although depletion by BSO was more sustained. However, the nuclear glutathione pool resisted depletion by BSO but not with DEM. Interestingly, cell proliferation was impaired by DEM, but not by BSO. Treating the cells simultaneously with DEM and with glutathione ethyl ester to restore intracellular GSH levels completely prevented the effects of DEM on cell proliferation.ConclusionsOur results demonstrate the importance of nuclear glutathione in the control of cell proliferation in 3T3 fibroblasts and suggest that a reduced nuclear environment is necessary for cells to progress in the cell cycle.

Glutathione – linking cell proliferation to oxidative stress

“…For example, the addition of BSO to 3T3 fibroblasts significantly decreased the total cellular GSH pool (108). However, only the cytosolic GSH pool was rapidly depleted in the presence of BSO and the nuclear GSH pool was less depleted (108).…”

“…Data showing that the nuclear GSH pool is more resistant to depletion than the cytosolic pool (108) suggest that mechanisms exist that facilitate GSH sequestration in the nucleus.…”

“…However, only the cytosolic GSH pool was rapidly depleted in the presence of BSO and the nuclear GSH pool was less depleted (108). Similarly, the addition of the sesterpenoid inhibitor Ophiobolin A to tobacco cells blocked the cell cycle at the S/G2 phases, trapping GSH in the nucleus (29).…”

Evaluation of the Role of Glutathione in the Lead-Induced Toxicity in Saccharomyces cerevisiae

“…GSH is depleted due to the reaction with chemicals like diethylmaleate or iodoacetamide; and (ii) by inhibition of GSH biosynthesis with an enzyme inhibitor, such as L-buthionine sulphoximine [13,15]. With the aim to test the effect of the absence of GSH, on Pb toxicity, by a different way (GSH biosynthesis inhibition was tested with Dgsh mutant strains), yeast cells were GSH depleted by treatment with iodoacetamide; this compound was selected due to its efficiency in GSH depletion, in a short…”

Defects in a New Class of Sulfate/Anion Transporter Link Sulfur Acclimation Responses to Intracellular Glutathione Levels and Cell Cycle Control

“…In mammals, low levels of reactive oxygen species stimulate cell cycle entry (Lee et al, 1998;Martindale and Holbrook, 2002;Boonstra and Post, 2004) by activating cell cycle regulators (Shackelford et al, 2000;Boonstra and Post, 2004;Macleod, 2008;Burhans and Heintz, 2009). Moreover, alterations in redox homeostasis can cause defects in cell cycle progression (Esposito et al, 1997;Reichheld et al, 1999;Alic et al, 2001;Menon et al, 2003;Markovic et al, 2009;Tsukagoshi et al, 2010). Glutathione is a thiol-containing tripeptide whose function is not only important to maintain redox homeostasis when coping with biotic and abiotic stresses (Cobbett et al, 1998;Ball et al, 2004;Rouhier et al, 2008;Foyer and Noctor, 2009;Mhamdi et al, 2010;Dubreuil-Maurizi and Poinssot, 2012;Shanmugam et al, 2012) but also acts as a redox signal or sensor for cell cycle control (Chiu et al, 2011;Chiu and Dawes, 2012).…”